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Activation of Notch1 signaling in neural progenitor cells (NPCs) induces self-renewal and inhibits neurogenesis. Upon neuronal differentiation, NPCs overcome this inhibition, express proneural genes to induce Notch ligands, and activate Notch1 in neighboring NPCs. The molecular mechanism that coordinates Notch1 inactivation with initiation of neurogenesis remains elusive. Here, we provide evidence that Prox1, a transcription repressor and downstream target of proneural genes, counteracts Notch1 signaling via direct suppression of Notch1 gene expression. By expression studies in the developing spinal cord of chick and mouse embryo, we showed that Prox1 is limited to neuronal precursors residing between the Notch1+ NPCs and post-mitotic neurons. Physiological levels of Prox1 in this tissue are sufficient to allow binding at Notch1 promoter and they are critical for proper Notch1 transcriptional regulation in vivo. Gain-of-function studies in the chick neural tube and mouse NPCs suggest that Prox1-mediated suppression of Notch1 relieves its inhibition on neurogenesis and allows NPCs to exit the cell cycle and differentiate. Moreover, loss-of-function in the chick neural tube shows that Prox1 is necessary for suppression of Notch1 outside the ventricular zone, inhibition of active Notch signaling, down-regulation of NPC markers, and completion of neuronal differentiation program. Together these data suggest that Prox1 inhibits Notch1 gene expression to control the balance between NPC self-renewal and neuronal differentiation.
Etwa 800 000 Bundesbürger leiden an rheumatoider Arthritis (RA), der häufigsten chronisch-entzündlichen Erkrankung der Gelenke. Obwohl die Forschung in den vergangenen Jahren erhebliche Fortschritte gemacht hat, sind die Ursachen dieser schmerzhaften, bisher unheilbaren Krankheit noch nicht im Einzelnen geklärt. In vielerlei Richtungen diskutiert wird eine Fehlsteuerung des Immunsystems, bei der körpereigene Gewebsmatrix, wie der Gelenkknorpel, von Zellen des Immunsystems angegriffen wird. Die Forschungen der Mediziner, auch der Frankfurter Gruppe, konzentrieren sich weltweit auf die entzündungsfördernden Faktoren, spezielle Zytokine, und die Hemmstoffe dieser Zytokine. Aus diesen Ansätzen resultieren die neuartigen "Biologics": gentechnisch hergestellte monoklonale Antikörper, die natürlich vorkommenden Wirkstoffen entsprechen. Sie richten sich spezifisch gegen bestimmte vom menschlichen Organismus gebildete Zytokine.
Dichterhäuser produzieren Mythen. Dies ist bei Hofmannsthals barockem Wohnhaus in Rodaun bei Wien nicht anders. Als Vorbesitzer seines Hauses erwähnt Hofmannsthal in einem Brief an Eberhard von Bodenhausen vom 16. März 1901 beiläufig einen Fürsten Trautson: das Haus sei "zur Zeit der Kaiserin Maria Theresia von einem Fürsten Trautsohn, der ein Schwarzkünstler gewesen sein soll, für seine Geliebte gebaut worden". Das gemeinhin als 'Schlösschen Fuchs' oder 'Fuchs-Schlössel' bezeichnete Anwesen wurde von Hofmannsthal von 1901 bis zu seinem Tod 1929 bewohnt und von seiner Familie noch bis 1937 gemietet. Das Landhaus aus dem 17./18. Jahrhundert, dessen Erbauungs- oder Umgestaltungsdatum nicht belegbar ist, wird in der Forschungsliteratur zu Hofmannsthal, in Zeitungsartikeln und in der Lokalgeschichtsschreibung kaum mit Trautsohn, sondern vielmehr mit einer anderen Vorbesitzerin in Verbindung gebracht: mit einer der Kaiserin Maria Theresia nahestehenden Gräfin Fuchs.
In the absence of an active prophylactic vaccine against HIV-1, passively administered, broadly neutralizing antibodies (bnAbs) identified in some chronically infected persons were shown to prevent HIV-1 infection in animal models. However, passive administration of bnAbs may not be suited to prevent sexual HIV-1 transmission in high-risk cohorts, as a continuous high level of active bnAbs may be difficult to achieve at the primary site of sexual transmission, the human vagina with its acidic pH. Therefore, we used Lactobacillus, a natural commensal in the healthy vaginal microbiome, to express bn nanobodies (VHH) against HIV-1 that we reported previously. After demonstrating that recombinant VHHA6 expressed in E. coli was able to protect humanized mice from mucosal infection by HIV-1Bal, we expressed VHHA6 in a soluble or in a cell-wall-anchored form in Lactobacillus rhamnosus DSM14870. This strain is already clinically applied for treatment of bacterial vaginosis. Both forms of VHHA6 neutralized a set of primary epidemiologically relevant HIV-1 strains in vitro. Furthermore, VHHA6 was still active at an acidic pH. Thus, lactobacilli expressing bn VHH potentially represent an attractive vector for the passive immunization of women in cohorts at high risk of HIV-1 transmission.
Taking blood via venipuncture is part of the necessary surveillance before and after liver transplantation. The spectrum of response from children and their parents is variable, ranging from a short and limited aversion to paralyzing phobia. The aim of this retrospective, cross-sectional study was to determine the level of anxiety amongst children during venipuncture, to compare the anxiety reported by children and parents, and to identify the factors affecting the children’s and parents’ anxiety in order to develop therapeutic strategies. In total, 147 children (aged 0–17 years, 78 female) and their parents completed questionnaires. Statistical analysis was performed using qualitative and quantitative methods. Results showed that the majority of children reported anxiety and pain during venipuncture. Younger children had more anxiety (self-reported or assessed by parents). Children and parental reports of anxiety were highly correlated. However, the child’s anxiety was often reported as higher by parents than by the children themselves. The child’s general anxiety as well as the parents’ perceived stress from surgical interventions (but not the number of surgical interventions) prompted parental report of child anxiety. For children, the main stressors that correlated with anxiety and pain were factors during the blood collection itself (e.g., feeling the puncture, seeing the syringe). Parental anxiety was mainly related to circumstances before the blood collection (e.g., approaching the clinic, sitting in the waiting room). The main stressors mentioned by parents were the child’s discomfort and their inability to calm the child. Results indicate that the children’s fear of factors during the blood collection, along with the parents’ perceived stress and helplessness as well as their anticipatory anxiety are important starting points for facilitating the drawing of blood from children before and after liver transplantation, thereby supporting a better disease course in the future.
The implications of telework are discussed controversially and research on its positive and negative effects has produced contradictory results. We explore voluntariness of employee telework as a boundary condition which may underpin these contradictory findings. Under normal circumstances, individuals who do more telework should perceive fewer disadvantages. However, during the COVID-19 pandemic, employees could no longer voluntarily choose to telecommute, as many organizations were forced to introduce telework by governmental regulations. In two studies, we examine whether the voluntary nature of telework moderates the association between the amount of telework and perceptions of disadvantage. In Study 1, we collected data before and during the COVID-19 pandemic (N = 327). Results show that pre-pandemic participants (who were more likely to voluntarily choose this form of work) reported fewer disadvantages the more telework they did, but this was not the case for employees during the COVID-19 pandemic. To validate these findings, we measured employees’ voluntariness of telework in Study 2 (N = 220). Results support the importance of voluntariness: Individuals who experience a high degree of voluntariness in choosing telework perceive fewer disadvantages the more they telework. However, the amount of telework was not related to reduced perceptions of disadvantages for those who experienced low voluntariness regarding the telecommuting arrangement. Our findings help to understand when telework is related to the perception of disadvantages and they can provide organizations with starting points for practical interventions to reduce the negative effects of telework.
The implications of telework are discussed controversially and research on its positive and negative effects has produced contradictory results. We explore voluntariness of employee telework as a boundary condition which may underpin these contradictory findings. Under normal circumstances, individuals who do more telework should perceive fewer disadvantages. However, during the COVID-19 pandemic, employees could no longer voluntarily choose to telecommute, as many organizations were forced to introduce telework by governmental regulations. In two studies, we examine whether the voluntary nature of telework moderates the association between the amount of telework and perceptions of disadvantage. In Study 1, we collected data before and during the COVID-19 pandemic (N = 327). Results show that pre-pandemic participants (who were more likely to voluntarily choose this form of work) reported fewer disadvantages the more telework they did, but this was not the case for employees during the COVID-19 pandemic. To validate these findings, we measured employees’ voluntariness of telework in Study 2 (N = 220). Results support the importance of voluntariness: Individuals who experience a high degree of voluntariness in choosing telework perceive fewer disadvantages the more they telework. However, the amount of telework was not related to reduced perceptions of disadvantages for those who experienced low voluntariness regarding the telecommuting arrangement. Our findings help to understand when telework is related to the perception of disadvantages and they can provide organizations with starting points for practical interventions to reduce the negative effects of telework.
The ability to respond appropriately to employees' work-related well-being requires leaders to pay attention to their employees' well-being in the first place. We propose that leaders' stress mindset, that is, the belief that stress is enhancing versus debilitating, may bias their perception of employees' well-being. We further propose that this judgment then influences leaders' intention to engage in or refrain from health-oriented leadership behavior, to express higher performance expectations, or to promote their employees. We expect this process to be stronger if leaders strongly identify with their team, increasing their perceived similarity with their employees. In three experiments (N1 = 198, N2 = 292, N3 = 250), we tested the effect of participants' stress mindset on their intention to show certain leadership behaviors, mediated by their perception of employee well-being (emotional exhaustion, somatic symptoms, work engagement) and moderated by their team identification. Our findings largely support the association between stress mindset and the perception of well-being. The results for the proposed mediation and the moderating function of identification were mixed. Overall, the results emphasize the critical role of leaders' stress mindset and may, thus, improve health promotion in organizations by helping leaders to adequately recognize employees' well-being and respond appropriately.
Although researchers and practitioners increasingly focus on health promotion in organizations, research has been mainly fragmented and fails to integrate different organizational levels in terms of their effects on employee health. Drawing on organizational climate and social identity research, we present a cascading model of organizational health climate and demonstrate how and when leaders' perceptions of organizational health climate are linked to employee well‐being. We tested our model in two multisource studies (NStudy 1 = 65 leaders and 291 employees; NStudy 2 = 401 leader–employee dyads). Results showed that leaders' perceptions of organizational health climate were positively related to their health mindsets (i.e., their health awareness). These in turn were positively associated with their health‐promoting leadership behavior, which ultimately went along with better employee well‐being. Additionally, in Study 1, the relationship between perceived organizational health climate and leaders' health mindsets was moderated by their organizational identification. High leader identification strengthened the relationship between perceived organizational health climate and leaders' health mindsets. These findings have important implications for theory and practice as they show how the dynamics of an organizational health climate can unfold in organizations and how it is related to employee well‐being via the novel concept of health‐promoting leadership.
Although researchers and practitioners increasingly focus on health promotion in organizations, research has been mainly fragmented and fails to integrate different organizational levels in terms of their effects on employee health. Drawing on organizational climate and social identity research, we present a cascading model of organizational health climate and demonstrate how and when leaders' perceptions of organizational health climate are linked to employee well-being. We tested our model in two multisource studies (NStudy 1 = 65 leaders and 291 employees; NStudy 2 = 401 leader–employee dyads). Results showed that leaders' perceptions of organizational health climate were positively related to their health mindsets (i.e., their health awareness). These in turn were positively associated with their health-promoting leadership behavior, which ultimately went along with better employee well-being. Additionally, in Study 1, the relationship between perceived organizational health climate and leaders' health mindsets was moderated by their organizational identification. High leader identification strengthened the relationship between perceived organizational health climate and leaders' health mindsets. These findings have important implications for theory and practice as they show how the dynamics of an organizational health climate can unfold in organizations and how it is related to employee well-being via the novel concept of health-promoting leadership.
Despite the increasing interest in leaders’ health-promoting behavior, the employees’ role in the effectiveness of such behavior and the mechanisms underlying how such leadership behavior affects their well-being have largely been ignored. Drawing on implicit leadership theories, we advance the health-oriented leadership literature by examining employees’ ideals, that is, their expectations regarding such leader behavior, as a moderating factor. We propose that higher expectations increase the association between actual health-oriented leader behavior and employee-rated leader-member relationships (LMX) and health-oriented behaviors by employees, which, in turn, positively relate to their well-being (here: exhaustion and work engagement). We tested our theoretical model in three studies, using a cross-sectional design (Study 1, N = 307), a two-wave time-lagged design (Study 2, N = 144) and an experimental design (Study 3, N = 173). We found that the effect of actual health-oriented leader behavior on LMX is contingent on employees’ ideal health-oriented leader behavior. Yet, for employees’ self-care behavior, the proposed moderation was only significant in Study 1. High expectations strengthened the relationship between actual health-oriented leader behavior with LMX and self-care behavior, which, in turn, were associated with less exhaustion and more work engagement (only LMX), supporting most of our mediation hypotheses. Our results highlight the pivotal role of employees’ expectations regarding leaders’ health support and help in building practical interventions with regard to leaders’ health promotion.
Recent studies have proven that Dimethylfumarate (DMF) has a marked anti-proliferative impact on diverse cancer entities e.g., on malignant melanoma. To explore its anti-tumorigenic potential, we examined the effects of DMF on human colon carcinoma cell lines and the underlying mechanisms of action. Human colon cancer cell line HT-29 and human colorectal carcinoma cell line T84 were treated with or without DMF. Effects of DMF on proliferation, cell cycle progression, and apoptosis were analyzed mainly by Bromodeoxyuridine (BrdU)- and Lactatdehydrogenase (LDH)-assays, caspase activation, flowcytometry, immunofluorescence, and immunoblotting. In addition, combinational treatments with radiation and chemotherapy were performed. DMF inhibits cell proliferation in both cell lines. It was shown that DMF induces a cell cycle arrest in G0/G1 phase, which is accompanied by upregulation of p21 and downregulation of cyclin D1 and Cyclin dependent kinase (CDK)4. Furthermore, upregulation of autophagy associated proteins suggests that autophagy is involved. In addition, the activation of apoptotic markers provides evidence that apoptosis is involved. Our results show that DMF supports the action of oxaliplatin in a synergetic manner and failed synergy with radiation. We demonstrated that DMF has distinct anti-tumorigenic, cell dependent effects on colon cancer cells by arresting cell cycle in G0/G1 phase as well as activating both the autophagic and apoptotic pathways and synergizes with chemotherapy.
Background: Peritonitis is responsible for thousands of deaths annually in Germany alone. Even source control (SC) and antibiotic treatment often fail to prevent severe sepsis or septic shock, and this situation has hardly improved in the past two decades. Most experimental immunomodulatory therapeutics for sepsis have been aimed at blocking or dampening a specific pro-inflammatory immunological mediator. However, the patient collective is large and heterogeneous. There are therefore grounds for investigating the possibility of developing personalized therapies by classifying patients into groups according to biomarkers. This study aims to combine an assessment of the efficacy of treatment with a preparation of human immunoglobulins G, A, and M (IgGAM) with individual status of various biomarkers (immunoglobulin level, procalcitonin, interleukin 6, antigen D-related human leucocyte antigen (HLA-DR), transcription factor NF-κB1, adrenomedullin, and pathogen spectrum).
Methods/design: A total of 200 patients with sepsis or septic shock will receive standard-of-care treatment (SoC). Of these, 133 patients (selected by 1:2 randomization) will in addition receive infusions of IgGAM for 5 days. All patients will be followed for approximately 90 days and assessed by the multiple-organ failure (MOF) score, by the EQ QLQ 5D quality-of-life scale, and by measurement of vital signs, biomarkers (as above), and survival.
Discussion: This study is intended to provide further information on the efficacy and safety of treatment with IgGAM and to offer the possibility of correlating these with the biomarkers to be studied. Specifically, it will test (at a descriptive level) the hypothesis that patients receiving IgGAM who have higher inflammation status (IL-6) and poorer immune status (low HLA-DR, low immunoglobulin levels) have a better outcome than patients who do not receive IgGAM. It is expected to provide information that will help to close the knowledge gap concerning the association between the effect of IgGAM and the presence of various biomarkers, thus possibly opening the way to a personalized medicine.
Trial registration: EudraCT, 2016–001788-34; ClinicalTrials.gov, NCT03334006. Registered on 17 Nov 2017.
Trial sponsor: RWTH Aachen University, represented by the Center for Translational & Clinical Research Aachen (contact Dr. S. Isfort).
Es wird über ein mindestens seit dem Jahre 2009 bestehendes Vorkommen des Neophyten Persicaria nepalensis (MEISN.) H. GROSS (Polygonaceae) im Waldgebiet "Die Haard" (Haltern am See, Kreis Recklinghausen) berichtet. Die Art stammt ursprünglich aus den gemäßigten und tropischen Zonen Asiens. Vorkommen in NRW waren bereits aus dem Sauerland und der Wahner Heide bekannt. Die Art stammt aus Wildacker-Ansaaten und ist in der Haard entlang schattiger Waldwege eingebürgert.
Es wird über Vorkommen des Rauen Straußgrases Agrostis scabra WILLD. (Poaceae) in Essen und in Nordrhein-Westfalen berichtet. Die Art stammt ursprünglich aus Nordamerika und Ostasien. Sie ist im Ruhrgebiet mindestens seit 1992 eingebürgert und besiedelt offene Standorte auf Zechenbrachen und an Talsperren.
Das Laerholz an der Grenze zwischen den Bochumer Stadtteilen Querenburg und Laer ist ein strukturreicher Laubmischwald mit Eichen und Buchen hohen Alters. Es wird von der Asbecke durchflossen. Trotz des hohen Bebauungsdrucks im letzten Jahrhundert durch das aufstrebende Universitätsviertel wurde das Laerholz erhalten, sodass der ehemals zum Haus Laer gehörende Forst heute rege zur Naherholung genutzt wird. Nachdem wir das Gebiet von West nach Ost fast komplett durchlaufen hatten, erreichten wir den evangelischen Friedhof an der Schattbachstr. und die Obstwiese des BUND Bochum. Sie wird nach Methoden des
Since the discovery of the reversible intercalation of lithium-ion materials associated with promising electrochemical properties, lithium-containing materials have attracted attention in the research and development of effective cathode materials for lithium-ion batteries. Despite various studies on synthesis, and electrochemical properties of lithium-based materials, fairly little fundamental optical and thermodynamic studies are available in the literature. Here, we report on the structure, optical, magnetic, and thermodynamic properties of Li-excess disordered rocksalt, Li1.3Nb0.3Mn0.4O2 (LNMO) which was comprehensively studied using powder X-ray diffraction, transient absorption spectroscopy, magnetic susceptibility, and low-temperature heat capacity measurements. Charge carrier dynamics and electron–phonon coupling in LNMO were studied using ultra-fast laser spectroscopy. Magnetic susceptibility and specific heat data are consistent with the onset of long-range antiferromagnetic order at the Néel temperatures of 6.5 (1.5) K. The effective magnetic moment of LNMO is found to be 3.60 μB. The temperature dependence of the inverse magnetic susceptibility follows the Curie–Weiss law in the high-temperature region and shows negative values of the Weiss temperature 52 K (3), confirming the strong AFM interactions.
Three new deep-sea species of Thyasiridae (Mollusca: Bivalvia) from the northwestern Pacific Ocean
(2023)
The Thyasiridae is one of the species-richest families in the abyssal and hadal zones of the northwestern Pacific Ocean. Many thyasirid species dominate benthic communities in terms of abundance and play an important role in the functioning of deep-sea ecosystems. Most of the thyasirid species in the region are new to science and have not been described. Based on the material collected from 1954 to 2016 by seven deep-sea expeditions, three new species of Thyasiridae (Parathyasira coani sp. nov., P. pauli sp. nov., and Thyasira kharkovensis sp. nov.) are described from the abyssal and hadal zones (3210–7540 m depth) of the Sea of Okhotsk, the Bering Sea, as well as the Kuril-Kamchatka and Japan trenches. The new species are remarkable among their congeners due to the combination of the following characters: an obliquely-rhomboidal shell with a weak and shallow posterior sulcus and a large prodissoconch with sculpture of lamellated folds. Comparisons with related species are provided.
The pA system is typically regarded in heavy ion collisions as a “cold” nuclear matter environment and thought to isolate and identify initial state effects due to the presence of multiple nucleons in the incoming nucleus. Moreover, pA collisions bridge the gap between peripheral AA collisions and the pp baseline to create a more complete understanding of underlying production mechanisms and how they evolve with multiplicity. Recent measurements at both RHIC and the LHC provide an indication, however, that the “cold” nuclear matter picture may be somewhat naïve.
Recent LHC results from the 2013 p–Pb run at √sNN = 5.02 TeV will be discussed.
A handling study to assess use of the Respimat(®) Soft Mist™ inhaler in children under 5 years old
(2015)
Background: Respimat® Soft Mist™ Inhaler (SMI) is a hand-held device that generates an aerosol with a high, fine-particle fraction, enabling efficient lung deposition. The study objective was to assess inhalation success among children using Respimat SMI, and the requirement for assistance by the parent/caregiver and/or a valved holding chamber (VHC).
Methods: This open-label study enrolled patients aged <5 years with respiratory disease and history of coughing and/or recurrent wheezing. Patients inhaled from the Respimat SMI (air only; no aerosol) using a stepwise configuration: “1” (dose released by child); “2” (dose released by parent/caregiver), and “3” (Respimat SMI with VHC, facemask, and parent/caregiver help). Co-primary endpoints included the ability to perform successful inhalation as assessed by the investigators using a standardized handling questionnaire and evaluation of the reasons for success. Inhalation profile in the successful handling configuration was verified with a pneumotachograph. Patient satisfaction and preferences were investigated in a questionnaire.
Results: Of the children aged 4 to <5 years (n=27) and 3 to <4 years (n=30), 55.6% and 30.0%, respectively, achieved success without a VHC or help; with assistance, another 29.6% and 10.0%, respectively, achieved success, and the remaining children were successful with VHC. All children aged 2 to <3 years (n=20) achieved success with the Respimat SMI and VHC. Of those aged <2 years (n=22), 95.5% had successful handling of the Respimat SMI with VHC and parent/caregiver help. Inhalation flow profiles generally confirmed the outcome of the handling assessment by the investigators. Most parent/caregiver and/or child respondents were satisfied with operation, instructions for use, handling, and ease of holding the Respimat SMI with or without a VHC.
Conclusions: The Respimat SMI is suitable for children aged <5 years; however, children aged <5 years are advised to add a VHC to complement its use.
Wie verfährt man mit einem kanonisierten Text, auf den die Selbstaussagen des Autors ein schiefes Licht werfen? Wenn dies auf Werke eines Autors zutrifft, dessen Briefwechsel ebenso Teil des Kanons ist, steht der Leser vor einer besonders heiklen Aufgabe. Man fühlt sich dazu aufgerufen, den Text gegenüber jener Instanz in Schutz zu nehmen, welche innerhalb der historischen Hermeneutik das letzte Wort hat: dem von Roland Barthes als Gott identifizierten Autor.
Während Tragödien für gewöhnlich mit der Größe des Helden stehen und fallen, drückt sich Friedrich Schiller betont distanziert über den Titelhelden aus Wallenstein aus: "Er hat nichts Edles, er erscheint in keinem einzelnen LebensAkt [sic] groß, er hat wenig Würde und dergleichen." Doch Schiller schickt sogleich eine Erklärung hinterher, weshalb er das dramatische Projekt trotzdem nicht aufzugeben gedenke. Er plane "auf rein realistischem Wege einen dramatisch großen Character in ihm aufzustellen, der ein ächtes Lebensprincip in sich hat." Ohne Verklärung (wie in der Jungfrau von Orleans) oder idealistische Überformung (wie im Don Carlos) solle Wallenstein groß erscheinen, was umso schwerer fällt, weil nichts für den Protagonisten einnimmt: "Seine Unternehmung ist moralisch schlecht, und sie verunglückt physisch. Er ist im Einzelnen nie groß, und im Ganzen kommt er um seinen Zweck. Er berechnet alles auf die Wirkung, und diese mißlingt." Die Beantwortung der Frage aber, wie es Schiller angestellt hätte, die "bloße Wahrheit" des Charakters für sich sprechen zu lassen, blieb zuletzt der Literaturwissenschaft überlassen, die im Laufe der Zeit ein breites Spektrum an Antwortmöglichkeiten zur Verfügung gestellt hat. Seit den 1990er Jahren hat sich der Ansatz verfestigt, dass es sich bei solchen Selbstaussagen nicht um Geburtsschmerzen, sondern um das Eingeständnis eines scheiternden Dramatikers handle. Wenn er Goethe gegenüber erwähnt, dass es ihm "fast zu arg [sei], wie der Wallenstein mir anschwillt" und dennoch bei der großzügigen Organisation des Textes bleibt, weckt er Erinnerungen an den Zauberlehrling, der sich eine Aufgabe stellt, der er letztendlich nicht Herr werden kann.
Observations show that, at the beginning of their existence, neutron stars are accelerated briskly to velocities of up to a thousand kilometers per second. We argue that this remarkable effect can be explained as a manifestation of quantum anomalies on astrophysical scales. To theoretically describe the early stage in the life of neutron stars we use hydrodynamics as a systematic effective-field-theory framework. Within this framework, anomalies of the Standard Model of particle physics as underlying microscopic theory imply the presence of a particular set of transport terms, whose form is completely fixed by theoretical consistency. The resulting chiral transport effects in proto-neutron stars enhance neutrino emission along the internal magnetic field, and the recoil can explain the order of magnitude of the observed kick velocities.
Vorwort
(2004)
Die Europäische Union erlies im Jahr 1992 die Fauna-Flora-Habitat-(FFH)Richtlinie, um einen besseren, grenzübergreifenden Schutz gefährdeter Lebensraume, Tier- und Pflanzenarten als Bestandteil des europäischen Naturerbes zu gewährleisten. Um dieses Ziel zu erreichen, wurde das europaweite Netz von Besonderen Schutzgebieten NATURA 2000 für die in Anhang I und Anhang II der FFH-Richtlinie aufgeführten Lebensraumtypen und Arten ausgewiesen. Ebenfalls von gemeinschaftlicher Bedeutung sind die streng zu schützenden Arten des Anhangs IV der FFH-Richtlinie.
Die Ehle entspringt am westlichen Fläminghang und mündet nach ca. 46 km als östlicher Nebenfluss in Höhe von Lostau in die Eibe. Die Quelle befindet sich bei Schweinitz 95 m über NN in einem Erlenbruch; der Mündungsbereich liegt etwa 44 m über NN. Das durchschnittliche Gefälle des Flusses beträgt 0,11 % (oberhalb Rosian ca. 0,3 %; Rosian-Loburg ca. 0,18 %; Unterlauf ca. 0,07 %). Unterhalb von Gommern (bei Vogelsang) wird die Ehle durch den Ehlekanal in den sogenannten Elbumflutkanal umgeleitet und fließt als Umflutehle durch zahlreiche Altwässer und ausgedehnte seenartige Abschnitte der Eibe zu. Der alte Ehleverlauf zwischen Vogelsang und Heyrothsberge ist nunmehr nur noch ein ichthyofaunistisch wertloser Wiesengraben. Der häufig gebrauchte Begriff "Umflutkanal" für den Abschnitt der Umflutehle ist irreführend. Bei normaler Wasserführung wechseln breite, stehende Gewässerteile mit schmalen und fließenden, niederungsbachähnlichen Gewässerstrecken ab. Nur in extremen Hochwasserzeiten dient dieser Ehleabschnitt der Umleitung eines Teiles des Elbewassers um die Landeshauptstadt Magdeburg herum.
Fische und Rundmäuler
(1995)
Neben der Havel, ihren Altarmen und Altwässern sind auch zahlreiche Meliorationsgräben, Fließe sowie austrocknungsgefährdete kleine Standgewässer für die Fischfauna im beschriebenen Gebiet von Bedeutung. Alle Fließgewässer im Gebiet der unteren Havel sind durchgehend begradigt und weisen die bekannten Nachteile von Flurbereinigungs- und Entwässerungsmaßnahmen auf. Die Hauptvorfluter sind zur Wasserhaltung mit Schöpfwerken und Staueinrichtungen versehen, die die Passierbarkeit für Wassertiere einschränken. Die Havel selbst weist als Bundeswasserstraße durch Uferbefestigungen und Ausbauten nur wenige ichthyologisch wertvolle Strukturen auf. Allen Gewässern gemeinsam ist eine starke Anreicherung mit Pflanzennährstoffen und damit ein hoher Trophiegrad.
Die Biologische Versuchsanstalt in Wien organisierte während der Monate Dezember 1903 und Jänner 1904 eine Reise durch Aegypten und den englisch-ägyptischen Sudan, und zwar zu dem Zwecke, lebendes Untersuchungsmaterial aus der Pflanzen- und Tierwelt jener Länder mit nach Europa zu bringen.
Insbesondere galt es. solche Arten kleinerer Lebewesen aufzufinden, welche sich in irgend einer Beziehung zu Versuchen auf dem Gebiete der experimentellen Morphologie (der Lehre yon den die Formbildung der Organismen verursachenden und beeinflussenden Faktoren) eignen. In dem Bestreben, das gesammelte Material lebend heimzubringen, bestand das Neue dieser Expedition im Vergleiche zu anderen wissenschaftlichen Sammelreisen, welche ihr Hauptaugenmerk auf konserviertes Material zu richten pflegen.
Sollten nun die Transporte und später die Versuche an den mitgebrachten Pflanzen und Tieren gelingen, so stellte sich als erstes Erfordernis die Wahl solcher Pflanzen und Tiere heraus welche bei Veränderungen der äusseren Lebensbedingungen über eine gewisse Widerstandskraft verfügen und daher vor allem auch.die Gefangenhaltung gut ertragen.
Die Teilnehmer der Reise waren: LEOPOLD RITTER v. PORTHEIM als Botaniker, Dr. HANS PRZIBRAM und der Verfasser vorliegender Reiseschilderung als Zoologen, sowie Dr. GUlDO BUNZEL als Jagdfreund und Amateurphotograph.
Use of drug-eluting balloon coronary intervention prior to living donor kidney transplantation
(2014)
Background: Kidney transplantation is the gold standard of therapy in patients with terminal renal insufficiency. Living donor transplantation is a well-established option in this field. Enlarging the donor's pool implicates the acceptance of an increased rate of comorbidities. Among them, coronary artery disease is a growing problem. An increasing number of patients, undergoing living donation, receive antiplatelet therapies due to coronary disease.
Case presentation: Here we report about the perioperative treatment with a drug-eluting balloon in a patient with major cardiac risk factors who underwent kidney transplantation.
Conclusion: At the current time no recommendation can be given for the routine use of drug-eluting balloons.
The human immunodeficiency virus type 1 (HIV-1) coreceptor use and viral evolution were analyzed in blood samples from an HIV-1 infected patient undergoing allogeneic stem cell transplantation (SCT). Coreceptor use was predicted in silico from sequence data obtained from the third variable loop region of the viral envelope gene with two software tools. Viral diversity and evolution was evaluated on the same samples by Bayesian inference and maximum likelihood methods. In addition, phenotypic analysis was done by comparison of viral growth in peripheral blood mononuclear cells and in a CCR5 (R5)-deficient T-cell line which was controlled by a reporter assay confirming viral tropism. In silico coreceptor predictions did not match experimental determinations that showed a consistent R5 tropism. Anti-HIV directed antibodies could be detected before and after the SCT. These preexisting antibodies did not prevent viral rebound after the interruption of antiretroviral therapy during the SCT. Eventually, transplantation and readministration of anti-retroviral drugs lead to sustained increase in CD4 counts and decreased viral load to undetectable levels. Unexpectedly, viral diversity decreased after successful SCT. Our data evidence that only R5-tropic virus was found in the patient before and after transplantation. Therefore, blocking CCR5 receptor during stem cell transplantation might have had beneficial effects and this might apply to more patients undergoing allogeneic stem cell transplantation. Furthermore, we revealed a scenario of HIV-1 dynamic different from the commonly described ones. Analysis of viral evolution shows the decrease of viral diversity even during episodes with bursts in viral load.
Im August 2006 brach die BTD erstmals in Mitteleuropa aus. Zunächst traten Fälle in Holland und Belgien auf, schnell folgten Deutschland und Frankreich, und schließlich auch Luxemburg. Betroffen waren vorwiegend Kühe und Schafe, vereinzelt Ziegen und Wildwiederkäuer. Überraschenderweise erkrankten neben Schafen auch zahlreiche Kühe schwer, und einige verendeten sogar. Als infektiöses Agens konnte der BTV-Serotyp 8 identifiziert werden, der niemals zuvor in Europa aufgetreten war. Bis zum Jahresende konnte sich die BTD insbesondere im Dreiländereck von Holland, Belgien und Deutschland weiter ausbreiten. Nach dem Animal Disease Notification System der EU waren Ende 2006 in den betroffenen fünf Ländern BTD-Ausbrüche in 2047 Viehwirtschaftsbetrieben bestätigt worden: Holland 456, Belgien 695, Deutschland 885, Frankreich 6 und Luxemburg 5 Obwohl die Hoffnung bestand, dass die Ceratopogoniden mit dem Einbruch des Winters verschwinden und keine Virustransmission mehr stattfinden würden, wurden neue Ausbrüche auch nachfolgend verzeichnet (75 weitere bis 1. Februar 2007, davon allein 67 in Deutschland; ProMED-Mail 2007), wobei bisher nicht klar ist, ob es sich tatsächlich um Neuinfektionen oder um verspätet diagnostizierte Infektionen aus 2006 handelt. Die Aktivitätsdichte der Gnitzen nahm gegen Ende 2006 mit sinkenden Temperaturen zwar ab, war jedoch zumindest bis zum 21. Dezember niemals gleich Null (Mehlhorn & al. 2007). Mit fortschreitender Dauer der Epizootie wurde auch eine geografische Ausbreitung nach Osten beobachtet. Anfang Februar 2007 waren fast alle deutschen Bundesländer von den BTD-Schutz- und Überwachungszonen betroffen (Abb. 1), in denen besondere Vorschriften für den Transport und Handel mit Wiederkäuern gelten (EU 2005).
Background A procedure for including activity against enveloped viruses in the post-contamination treatment of hands has been recommended, but so far no European standard is available to implement it. In 2004, the German Robert Koch-Institute (RKI) and the German Association for the Control of Virus Disease (DVV) suggested that vaccinia virus and bovine viral diarrhea virus (BVDV) should be used as test viruses in a quantitative suspension test to determine the activity of a disinfectant against all enveloped viruses. Methods We have studied the activities of three commonly-used alcohol-based hand rubs (hand rub A, based on 45% propan-2-ol, 30% propan-1-ol and 0.2% mecetronium etilsulfate; hand rub B, based on 80% ethanol; hand rub C, based on 95% ethanol) against vaccinia virus and BVDV, and in addition against four other clinically relevant enveloped viruses: herpes simplex virus (HSV) types 1 and 2, and human and avian influenza A virus. The hand rubs were challenged with different organic loads at exposure time of 15, 30 and 60 s. According to the guidelines of both BGA/RKI and DVV, and EN 14476:2005, the reduction of infectivity of each test virus was measured on appropriate cell lines using a quantitative suspension test. Results All three alcohol-based hand rubs reduced the infectivity of vaccinia virus and BVDV by >= 4 log10-steps within 15 s, irrespective of the type of organic load. Similar reductions of infectivity were seen against the other four enveloped viruses within 15 s in the presence of different types of organic load. Conclusions Commonly used alcohol-based hand rubs with a total alcohol concentration >= 75% can be assumed to be active against clinically relevant enveloped viruses if they effectively reduce the infectivities of vaccinia virus and BVDV in a quantitative suspension test.
Fast unbemerkt und wider alle Erwartung ist der Laie ausgerechnet unter den Bedingungen einer modernen, hoch differenzierten, aber inzwischen weitgehend entbürgerlichten Massengesellschaft zum Experten seiner selbst ernannt worden. Konsumenten, Studienfachwähler, Spiritualitätsbegeisterte und andere von ihrer Eigenkompetenz überzeugte Meinungsinhaber bekennen sich inzwischen selbstbewusst zu den Dogmen der Selbstautorisierung, Selbstbestimmung, Selbstermächtigung, Selbstherrlichkeit, Selbsterkenntnis und Selbstverliebtheit, obwohl oder gerade weil sie jedem philosophischen System abhold sind, alle Ideen für weitgehend überflüssigen Ballast und die bürgerliche Gesellschaft längst nicht mehr für eine diskutierende Klasse halten. Das spätestens seit der Reformation geltende Zeugnis vom "Priestertum aller Gläubigen": ist es im Untergang der bürgerlichen Gesellschaft endlich zur selbstverständlichen Wahrheit geworden? Das Fragezeichen ist der Ausgangspunkt der nachfolgenden Überlegungen.
wo different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l.) during the Cloud and Aerosol Characterization Experiment (CLACE 6) in February and March 2007. During mixed phase cloud events ice crystals from 5 μm up to 20 μm were separated from large ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI). During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR) were analyzed for size and composition by two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT) and a commercial Aerosol Time of Flight Mass Spectrometer (ATOFMS, TSI Model 3800). During CLACE 6 the SPLAT instrument characterized 355 individual ice residues that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 particles. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS) and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094). The measurements showed that mineral dust particles were strongly enhanced in the ice particle residues. 57% of the SPLAT spectra from ice residues were dominated by signatures from mineral compounds, and 78% of the ATOFMS spectra. Sulfate and nitrate containing particles were strongly depleted in the ice residues. Sulfate was found to dominate the droplet residues (~90% of the particles). The results from the two different single particle mass spectrometers were generally in agreement. Differences in the results originate from several causes, such as the different wavelength of the desorption and ionisation lasers and different size-dependent particle detection efficiencies.
Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l.) during the Cloud and Aerosol Characterization Experiment (CLACE 6) in February and March 2007. During mixed phase cloud events ice crystals from 5–20 micro m were separated from larger ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI). During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR) were analyzed for size and composition by the two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT) and a commercial Aerosol Time-of-Flight Mass Spectrometer (ATOFMS, TSI Model 3800). During CLACE 6 the SPLAT instrument characterized 355 individual IR that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 IR. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS) and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094). The measurements showed that mineral dust was strongly enhanced in the ice particle residues. Close to all of the SPLAT spectra from ice residues did contain signatures from mineral compounds, albeit connected with varying amounts of soluble compounds. Similarly, close to all of the ATOFMS IR spectra show a mineral or metallic component. Pure sulfate and nitrate containing particles were depleted in the ice residues. Sulfate and nitrate was found to dominate the droplet residues (~90% of the particles). The results from the two different single particle mass spectrometers were generally in agreement. Differences in the results originate from several causes, such as the different wavelength of the desorption and ionisation lasers and different size-dependent particle detection efficiencies.
In the face of the worldwide COVIV-19 pandemic, refugees represent a particularly vulnerable group with respect to access to health care and information regarding preventive behavior. In an online survey the Perceived Vulnerability to Disease Scale, self-reported changes in preventive and risk behaviors, knowledge about COVID-19, and psychopathological symptoms (PHQ-4) were assessed. The convenience sample consisted of n = 76 refugees (n = 45 Arabic speaking, n = 31 Farsi speaking refugees) and n = 76 German controls matched with respect to age and sex. Refugees reported a significantly larger fear of infection, significantly less knowledge about COVID-19, and a higher frequency of maladaptive behavior, as compared to the control group. This study shows that refugees are more vulnerable to fear of infection and maladaptive behaviors than controls. Culturally adapted, easily accessible education about COVID-19 may be beneficial in improving knowledge and preventive behaviors related to COVID-19.
Culturally adapted cognitive behavioral therapy (CA-CBT) is a well-evaluated, transdiagnostic group intervention for refugees that uses psychoeducation, meditation, and stretching exercises. In the current study, we added problem-solving training to CA-CBT and evaluated this treatment (i.e., CA-CBT+) in a randomized controlled pilot trial with a sample of Farsi-speaking refugees. Participants (N = 24) were male refugees diagnosed with DSM-5 PTSD, major depressive disorder, and anxiety disorders who were randomly assigned to either a treatment or waitlist control (WLC) condition. Treatment components were adapted both to the specific cultural background and the current social problems of asylum seekers. Assessments were performed pretreatment, 12-weeks posttreatment, and 1-year follow-up. The primary treatment outcome was the General Health Questionnaire (GHQ-28); secondary outcome measures included the Posttraumatic Stress Disorder Checklist, Patient Health Questionnaire, Somatic Symptom Scale, World Health Organization Quality of Life, and Emotion Regulation Scale. Eleven of 12 participants were randomized to CA-CBT+ completed treatment. Based on intent-to-treat data, large between-group effect sizes were seen at posttreatment in the GHQ-28, d = 3.0, and for most secondary outcome measures. Improvements for individuals in the treatment group decreased at 1-year follow-up, but effect sizes demonstrated continued large improvements on all measures as compared to pretreatment levels. In summary, CA-CBT+ led to large improvements in general psychopathological distress and quality of life, which were maintained in the long term. In addition, the dropout rate was very low, with delivery in group format. Thus, problem-solving training appears to be a promising addition to CA-CBT.
Background: Within the last decades, there has been increasing research on the occurrence of chemicals of emerging concern (CECs) in aquatic ecosystems due to their potential adverse effects on freshwater organisms and risk to human health. However, information on CECs in freshwater environments in sub-Saharan countries is very limited. Here, we investigated the occurrence of CECs in snails and sediments collected from 48 sites within the Lake Victoria South Basin, Kenya, which have been previously investigated for water contamination. Samples were analyzed by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) with a target list of 429 compounds.
Results: In total, 30 compounds have been detected in snails and 78 in sediment samples, compared to 79 previously identified compounds in water. By extending the monitoring of CECs to snails and sediments, we found 68 compounds that were not previously detected in water. These compounds include the anti-cancer drug anastrozole, detected for the first time in the Kenyan environment. Individual compound concentrations were detected up to 480 ng/g wet weight (N-ethyl-o-toluenesulfonamide) in snails and 110 ng/g organic carbon (pirimiphos-methyl) in sediments. Higher contaminant concentrations were found in agricultural sites than in areas not impacted by anthropogenic activities. Crustaceans were the organisms at greatest toxic risk from sediment contamination [toxic unit (TU) up to 0.99] with diazinon and pirimiphos-methyl driving this risk. Acute and chronic risks to algae were driven by diuron (TU up to 0.24), whereas fish were found to be at low-to-no acute risk (TU up to 0.007).
Conclusions: The compound classes present at the highest frequencies in all matrices were pesticides and biocides. This study shows substantial contamination of surface water in rural western Kenya. By filling data gaps on contamination of sediments and aquatic biota, our study reveals that CECs pose a substantial risk to environmental health in Kenya demanding for monitoring and mitigation.
Den 'Gray Room' des künstlerischen Kollektivs Archizoom als Metapher für eine kuratorische Situation avant la lettre nach Bismarck aufgreifend, verbindet Nicole Kandioler diesen mit dem Konzept des "Sensoriums" nach Jacques Rancière, mit dem Letzterer das Setting des Aufeinandertreffens von Kunst und Politik beschreibt. Der als Sensorium gedachte Gray Room entfaltet in der Gegenüberstellung und Konfrontation dreier künstlerischer Positionen (Alfons Mucha, Kara Walker und Kateřina Šedá) konkrete Politiken des Medialen, die sich an post-imperialen, post-kolonialen und post-sozialistischen Motiven abarbeiten.
In der dritten Ausgabe des Periodicals möchten wir nach den Schnittstellen zwischen dem Bereich der Medienkomparatistik und dem Feld des Kuratorischen fragen, wobei wir die Verschiebung des 'Kuratierens' als inszenierende Praxis zum 'Kuratorischen' als Grundbedingung "des Öffentlich-Werdens von Kunst" sowie der Diskursivierung von medienwissenschaftlichem Wissen (über Kunst) zum Ausgangspunkt unserer Überlegungen nehmen.
During January/February 2013, at the High Alpine Research Station Jungfraujoch a measurement campaign was carried out, which was centered on atmospheric ice-nucleating particles (INP) and ice particle residuals (IPR). Three different techniques for separation of INP and IPR from the non-ice-active particles are compared. The Ice Selective Inlet (ISI) and the Ice Counterflow Virtual Impactor (Ice-CVI) sample ice particles from mixed phase clouds and allow for the analysis of the residuals. The combination of the Fast Ice Nucleus Chamber (FINCH) and the Ice Nuclei Pumped Counterflow Virtual Impactor (IN-PCVI) provides ice-activating conditions to aerosol particles and extracts the activated INP for analysis.Collected particles were analyzed by scanning electron microscopy and energy-dispersive X-ray microanalysis to determine size, chemical composition and mixing state. All INP/IPR-separating techniques had considerable abundances (median 20 – 70 %) of instrumental contamination artifacts (ISI: Si-O spheres, probably calibration aerosol; Ice-CVI: Al-O particles; FINCH+IN-PCVI: steel particles). Also, potential sampling artifacts (e.g., pure soluble material) occurred with a median abundance of < 20 %. While these could be explained as IPR by ice break-up, for INP their IN-ability pathway is less clear. After removal of the contamination artifacts, silicates and Ca-rich particles, carbonaceous material and metal oxides were the major INP/IPR particle types separated by all three techniques. Soot was a minor contributor. Lead was detected in less than 10 % of the particles, of which the majority were internal mixtures with other particle types. Sea-salt and sulfates were identified by all three methods as INP/IPR. Most samples showed a maximum of the INP/IPR size distribution at 400 nm geometric diameter. In a few cases, a second super-micron maximum was identified. Soot/carbonaceous material and metal oxides were present mainly in the submicron range. ISI and FINCH yielded silicates and Ca-rich particles mainly with diameters above 1 μm, while the Ice-CVI also separated many submicron IPR. As strictly parallel sampling could not be performed, a part of the discrepancies between the different techniques may result from variations in meteorological conditions and subsequent INP/IPR composition. The observed differences in the particle group abundances as well as in the mixing state of INP/IPR express the need for further studies to better understand the influence of the separating techniques on the INP/IPR chemical
composition.
The Tijanya brotherhood founded by Cheikh Ahmed TIJANI in the second half of the XVIIIth century achieved a spectacular breakthrough in West Africa by the middle of the XIXth century. It was adopted and championed by the main figures of the resistance to the French colonial penetration : Cheikh Umar al-Futi TALL and Ahmadou Mahdiyu BA who were introduced to it respectively by Mohamed el-Ghali in Medina and Mohamed el-Hafez, and Id-on-Ali in Mederdra, Mauritania. Mamadou Lamine Dramé from the Gajaaga and Samba Diadana Ac also were figures of the anticolonial resistance who embraced Tijanya. Ahmadou Cheikhou, Cheikh Umar TALL's successor and eldest son, too was a tijane anticolonial hero whom Archinard's men killed in 1891, after his empire had gone through a long period of turmoil.
Motivated by recent experimental suggestions of charge-order-driven ferroelectricity in organic charge-transfer salts, such as κ-(BEDT-TTF)2Cu[N(CN)2]Cl, we investigate magnetic and charge-ordered phases that emerge in an extended two-orbital Hubbard model on the anisotropic triangular lattice at 3/4 filling. This model takes into account the presence of two organic BEDT-TTF molecules, which form a dimer on each site of the lattice, and includes short-range intramolecular and intermolecular interactions and hoppings. By using variational wave functions and quantum Monte Carlo techniques, we find two polar states with charge disproportionation inside the dimer, hinting to ferroelectricity. These charge-ordered insulating phases are stabilized in the strongly correlated limit and their actual charge pattern is determined by the relative strength of intradimer to interdimer couplings. Our results suggest that ferroelectricity is not driven by magnetism, since these polar phases can be stabilized also without antiferromagnetic order and provide a possible microscopic explanation of the experimental observations. In addition, a conventional dimer-Mott state (with uniform density and antiferromagnetic order) and a nonpolar charge-ordered state (with charge-rich and charge-poor dimers forming a checkerboard pattern) can be stabilized in the strong-coupling regime. Finally, when electron–electron interactions are weak, metallic states appear, with either uniform charge distribution or a peculiar 12-site periodicity that generates honeycomb-like charge order.
Au Tchad, à cause de ses retombées financières une attention particulière est prêtée aux arbres à karité (Vitella- ria paradoxa C.F.Gaertn.). Cependant, cette culture est menacée par les plantes vasculaires parasites de la famille des Lo- ranthaceae. La présente étude a été effectuée dans 3 sites dans la région du Mandoul pour évaluer l’ampleur des attaques de Loranthaceae (gui africain) sur des arbres en fonction des classes de circonférence du tronc à 1,5 cm du sol. Elle a consisté à dénombrer sur une de surface, les arbres à karité infestés et les touffes de parasites rencontrées sur ces arbres, afin de dé- terminer leur taux et leur intensité d’infestation. Les résultats obtenus montrent que Tapinanthus dodoneifolus (DC) Danser a été trouvée comme la seule espèce de Loranthaceae qui parasite les arbres karité étudiés dans la zone d’étude. Le taux moyen d’infestation estimé à 73% augmente avec l’âge des arbres karité. La moyenne d’intensité de l’infestation/arbre (2,75 touffes à Békôh, 2,27 à Yomi and 2,04 à Bébopen) montre que Tapinanthus dodoneifolus constitue une réelle menace pour les peu- plements de karité dans la zone d’étude. Il reste à rechercher le seuil d’infestation qui provoque une réduction significative de la fructification. Pour l’instant, bien que pénible à cause de la hauteur des arbres adultes, la lutte mécanique contre les Ta- pinanthus par la coupe systématique des branches infestées est urgente dans les parcs à karité dans cette zone d’étude.