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Purpose: To evaluate the efficacy of the virtual reality training simulator Eyesi to prepare surgeons for performing pars plana vitrectomies and its potential to predict the surgeons’ performance.
Methods: In a preparation phase, four participating vitreoretinal surgeons performed repeated simulator training with predefined tasks. If a surgeon was assigned to perform a vitrectomy for the management of complex retinal detachment after a surgical break of at least 60 hours it was randomly decided whether a warmup training on the simulator was required (n = 9) or not (n = 12). Performance at the simulator was measured using the built-in scoring metrics. The surgical performance was determined by two blinded observers who analyzed the video-recorded interventions. One of them repeated the analysis to check for intra-observer consistency. The surgical performance of the interventions with and without simulator training was compared. In addition, for the surgeries with simulator training, the simulator performance was compared to the performance in the operating room.
Results: Comparing each surgeon’s performance with and without warmup trainingshowed a significant effect of warmup training onto the final outcome in the operating room. For the surgeries that were preceeded by the warmup procedure, the performance at the simulator was compared with the operating room performance. We found that there is a significant relation. The governing factor of low scores in the simulator were iatrogenic retinal holes, bleedings and lens damage. Surgeons who caused minor damage in the simulation also performed well in the operating room.
Conclusions: Despite the large variation of conditions, the effect of a warmup training as well as a relation between the performance at the simulator and in the operating room was found with statistical significance. Simulator training is able to serve as a warmup to increase the average performance.
Cryptochromes, blue-light absorbing proteins involved in the circadian clock, have been proposed to be the receptor molecules of the avian magnetic compass. In birds, several cryptochromes occur: Cryptochrome 2, Cryptochrome 4 and two splice products of Cryptochrome 1, Cry1a and Cry1b. With an antibody not distinguishing between the two splice products, Cryptochrome 1 had been detected in the retinal ganglion cells of garden warblers during migration. A recent study located Cry1a in the outer segments of UV/V-cones in the retina of domestic chickens and European robins, another migratory species. Here we report the presence of cryptochrome 1b (eCry1b) in retinal ganglion cells and displaced ganglion cells of European Robins, Erithacus rubecula. Immuno histochemistry at the light microscopic and electron microscopic level showed eCry1b in the cell plasma, free in the cytosol as well as bound to membranes. This is supported by immuno blotting. However, this applies only to robins in the migratory state. After the end of the migratory phase, the amount of eCry1b was markedly reduced and hardly detectable. In robins, the amount of eCry1b in the retinal ganglion cells varies with season: it appears to be strongly expressed only during the migratory period when the birds show nocturnal migratory restlessness. Since the avian magnetic compass does not seem to be restricted to the migratory phase, this seasonal variation makes a role of eCry1b in magnetoreception rather unlikely. Rather, it could be involved in physiological processes controlling migratory restlessness and thus enabling birds to perform their nocturnal flights.
Background and Objectives: Tick-borne encephalitis (TBE) still represents a considerable medical and health economic problem in Europe and entails a potential threat to travellers. The aim of this study was to characterise the conditions of severe TBE by precisely recording its clinical variants, the related neuroimaging features, and the variant-specific long-term outcome and by identifying predictors for severe courses.
Methods: A cohort of 111 TBE patients (median age 51, range 17–75 years; 42% females) was analysed prospectively. Data were acquired from the department of neurology, University Hospital Heidelberg, and the infectious diseases registry of the Robert-Koch institute Berlin. Neurological status was ascertained by protocol at admission and discharge and the degree of disability was scored using the modified RANKIN Scale (mRS; clinical score addressing neurological disability, range from 0, healthy to 6, dead) at admission and at follow-up. Follow-up examination was conducted by means of a telephone interview. To identify independent predictors for severe TBE and functional outcome, modelled logistic regression was performed. MRI changes were correlated with infection variants. To assess alpha-motor neuron injury patterns, we used high resolution magnetic resonance neurography (hrMRN). Analyses were performed at the Department of Neurology, University Hospital, University of Heidelberg from April 2004 through September 2014
Results: Acute course: 3.6% of patients died during the acute infection. All patients with a lethal course suffered from meningoencephaloradiculitis (MER, 14.4% of the cohort), which is associated with a significantly higher risk of requiring intensive care (p = 0.004) and mechanical ventilation (p<0.001) than menigoencephalitis (ME, 27.9% of the cohort). At admission, both MER and ME groups were severely affected, with the MER group having a statistically higher mRS score (median of 5 in the MER groups versus 4 in the ME group; p<0.001). Long-term outcome: outcome for MER was considerably worse (median mRS = 4) than for ME (mRS = 1, p<0.0001) and meningitis (mRS = 0, 57.7% of the cohort). Risk factors: advanced age (p<0.001) and male gender (p = 0.043) are independent risk factors for a severe infection course. Furthermore, we identified pre-existing diabetes mellitus (p = 0.024) as an independent risk factor for MER. In MER, alpha-motor neuron injury accounts for the poor prognosis confirmed by hrMRN.
Conclusion and Relevance: These data provide critical information for neurologists and other health professionals to use in evaluating TBEV patients who live in or travel to endemic areas. This information can be used to classify clinical presentation and estimate infection-associated complications and individual prognosis. Furthermore, the risk for severe, disabling infections in older patients should prompt general practitioners to recommend and encourage vaccination to those patients living in or travelling to endemic areas.
Anpassung an den Klimawandel am Beispiel Namibia +++ TransImpact – wissenschaftliche Grundlagen für transdisziplinäres Forschen +++ ISOE-Publikation zur Evaluierung von Wasser-Partnerschaften erschienen +++ Wissenschaft und Zivilgesellschaft: Ziemlich beste Freunde? +++ Für ein neues Verständnis von Wissenschaftskommunikation +++ Aus dem ISOE: Biodiversitätsexpertin in internationalen Beirat OpenNESS berufen +++ Termine +++ Publikationen
Institutsbericht 2015 des ISOE ist erschienen +++ Arzneimittelrückstände im Wasserkreislauf: Empfehlungen aus dem Forschungsprojekt Sauber+ +++ Mobiles Baden-Württemberg – Neues Forschungsprojekt zu nachhaltiger Mobilität +++ ISOE-Lecture: Transdisziplinäre Forschung in einem neuen Erdzeitalter? Die Debatte um das Anthropozän +++ ISOE-Forscherinnen beim Future Earth Summit in Berlin +++ Aus dem ISOE: Nachhaltigkeitsstrategie Hessen: ISOE unterschreibt Zielvereinbarung für nachhaltige Beschaffung +++ Termine +++ Publikationen
„Keine Gesellschaft ohne Natur“ – Beiträge zur Entwicklung der Sozialen Ökologie erschienen +++ ISOE beim Symposium deutscher Mobilitäts- und Verkehrsforscher in Berlin +++ Arzneimittelrückstände im Wasserkreislauf: Technische Lösungen stoßen an ihre Grenzen +++ Stakeholder im Forschungsprozess – für den naturnahen Umbau der Nidda +++ Neuer Stromspiegel für Deutschland: Ergebnisse aus Forschungsprojekt von ISOE und Öko-Institut +++ Best Paper Award der Zeitschrift GAIA: ISOE-Beitrag unter den drei Erstplatzierten +++ Aus dem ISOE: Girls'Day 2016: Zukunftstag für Mädchen am ISOE +++ Termine +++ Publikationen
Franz von Assisi is seen as a champion of charity in favour of the poor ones. However that is not true. Poverty has not to be eliminated but praised as the most essential quality of human existence.
Hygroscopicity of nanoparticles produced from homogeneous
nucleation in the CLOUD experiments
(2016)
Sulfuric acid, amines and oxidized organics have been found to be important compounds in the nucleation and initial growth of atmospheric particles. Because of the challenges involved in determining the chemical composition of objects with very small mass, however, the properties of the freshly nucleated particles and the detailed pathways of their formation processes are still not clear. In this study, we focus on a challenging size range, i.e., particles that have grown to diameters of 10 and 15 nm following nucleation, and measure their water uptake. Water uptake is useful information for indirectly obtaining chemical composition of aerosol particles. We use a nanometer-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) at subsaturated conditions (ca. 90 % relative humidity at 293 K) to measure the hygroscopicity of particles during the seventh Cosmics Leaving OUtdoor Droplets (CLOUD7) campaign performed at CERN in 2012. In CLOUD7, the hygroscopicity of nucleated nanoparticles was measured in the presence of sulfuric acid, sulfuric acid–dimethylamine, and sulfuric acid–organics derived from α-pinene oxidation. The hygroscopicity parameter κ decreased with increasing particle size, indicating decreasing acidity of particles. No clear effect of the sulfuric acid concentration on the hygroscopicity of 10 nm particles produced from sulfuric acid and dimethylamine was observed, whereas the hygroscopicity of 15 nm particles sharply decreased with decreasing sulfuric acid concentrations. In particular, when the concentration of sulfuric acid was 5.1 × 106 molecules cm−3 in the gas phase, and the dimethylamine mixing ratio was 11.8 ppt, the measured κ of 15 nm particles was 0.31 ± 0.01: close to the value reported for dimethylaminium sulfate (DMAS) (κDMAS ∼ 0.28). Furthermore, the difference in κ between sulfuric acid and sulfuric acid–imethylamine experiments increased with increasing particle size. The κ values of particles in the presence of sulfuric acid and organics were much smaller than those of particles in the presence of sulfuric acid and dimethylamine. This suggests that the organics produced from α-pinene ozonolysis play a significant role in particle growth even at 10 nm sizes.
This thesis develops a conceptual framework for a better understanding of the impact of slow-onset climate and environmental changes on human migration in developing countries. Its regional focus is on the West African Sahel, where the majority of the population depends on agriculture and thus is highly vulnerable to environmental changes. Migration from fragile environments is predominantly considered one of several household strategies to adapt to and minimise the risk of environmental stress. Based on qualitative and quantitative data from two selected rural study areas, Bandiagara in Mali and Linguère in Senegal, this thesis analyses the drivers of migration from the two areas.
The findings illustrate that, even though people highly depend on the natural environment, migration motives are manifold and that migration often is not a household strategy to cope with environmental changes. Although environmental conditions shape migration in the region and the migrants’ support is crucial for most households, environmental stress plays a relatively small role as a driver of migration - at least in Mali, where it is considerably less important than in Senegal. On the contrary, migration is often driven by better opportunities elsewhere rather than by livelihood stressors in the home area. Particularly the migration of young people is often an individual rather than a household decision and influenced by individual aspirations, such as aspirations for consumer goods or a better future, rather than by environmental stress.
This thesis claims that research should consider people’s capabilities to migrate or to stay as well as their individual aspirations and preferences - in addition to the household’s needs and the opportunities elsewhere. This is important in order to explain why some people stay in and others migrate from an area affected by environmental stress, though living under similar conditions. Depending on people’s capabilities to choose freely between staying and migrating and their preferences and aspirations for one or the other activity, people can either be “voluntary migrants”, “voluntary non-migrants”, “forced migrants” or “trapped people”.
Moreover, it is important to consider social trends and transformation processes in the analysis of the linkages between environment change and migration. Higher education levels and aspirations to a “modern” lifestyle among young people, for instance, might decrease the impact of environmental factors on migration, despite worsening environmental conditions.
U radu se raspravlja o leksikografskome statusu dvorječnih pozdrava dobro jutro, dobar dan, dobra večer i laku noć u hrvatskim rječnicima te se upućuje i na strane leksikografske pristupe. Naglasak je na značenjskim i komunikacijskim obilježjima pozdrava koja ih određuju kao posebnu leksičku skupinu te se predlaže da dvorječni pozdravi kao i jednorječni (zdravo, zbogom, doviđenja) postanu samostalne rječničke natuknice.
Donose se neke nove spoznaje o Lajpciškom lekcionaru, ćiriličnom rukopisu najvjerojatnije iz šestog ili sedmog desetljeća XVI. stoljeća. Ponajprije je riječ o rezultatima analize vodenih znakova, što je osobito važno jer je datacija rukopisa u literaturi bila prijeporna, a zatim i o novim podacima o knjižnici i signaturi rukopisa. Također se, u bliskoj vezi s analizom folijacije rukopisa, izlaže jedna važna tekstološka spoznaja koja pouzdano pokazuje da je predložak bio cjelovit, što indirektno osnažuje tezu da rukopisu na početku nedostaje devet listova, a ne, kako je tvrdio Joseph Schütz, samo jedan.
The growth of aerosol due to the aqueous phase oxidation of sulfur dioxide by ozone was measured in laboratory-generated clouds created in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN). Experiments were performed at 10 and −10 °C, on acidic (sulfuric acid) and on partially to fully neutralised (ammonium sulfate) seed aerosol. Clouds were generated by performing an adiabatic expansion – pressurising the chamber to 220 hPa above atmospheric pressure, and then rapidly releasing the excess pressure, resulting in a cooling, condensation of water on the aerosol and a cloud lifetime of approximately 6 min. A model was developed to compare the observed aerosol growth with that predicted using oxidation rate constants previously measured in bulk solutions. The model captured the measured aerosol growth very well for experiments performed at 10 and −10 °C, indicating that, in contrast to some previous studies, the oxidation rates of SO2 in a dispersed aqueous system can be well represented by using accepted rate constants, based on bulk measurements. To the best of our knowledge, these are the first laboratory-based measurements of aqueous phase oxidation in a dispersed, super-cooled population of droplets. The measurements are therefore important in confirming that the extrapolation of currently accepted reaction rate constants to temperatures below 0 °C is correct.
Der Beitrag untersucht das in jüngerer Zeit verstärkt diskutierte Phänomen einer – tatsächlichen oder vermeintlichen – „anglo-amerikanischen Rechts-hegemonie“. Es geht dabei um die Frage, ob die Rechtsordnungen Deutschlands und der Europäischen Union unter eine Vormachtstellung des amerikanischen Rechtsdenkens und amerikanischer Regelungsmuster geraten sind oder eine solche vielleicht sogar selbst aktiv befördert haben. In dem Beitrag wird diese Diskussion aus zivilrechtlicher Perspektive aufgegriffen. Nach einer Konkretisierung des Topos der Rechtshegemonie werden dabei zunächst einige Grundcharakteristika des amerikanischen Rechtssystems und des deutschen Rechtssystems gegenübergestellt und zusammengefasst, in welchen Bereichen das deutsche und das europäische Recht in den vergangenen Jahrzehnten durch amerikanische Denk- und Regelungsmuster überformt worden sind. Im Anschluss erfolgt eine Bewertung der zuvor skizzierten Entwicklung, wobei die Unterscheidung zwischen einem intrinsisch orientierten und einem funktional orientierten Verständnis von Rechtskultur als ein Kernproblem der jüngeren rechtsvergleichenden Diskussion im Zentrum steht. Im Ergebnis wird eine tendenziell skeptische Perspektive gegenüber dem suggestiven Bild eines Wettbewerbs der Rechtsordnungen eingenommen und die in jüngerer Zeit häufig geäußerte These der globalfunktionalen Überlegenheit eines wettbewerbsorientierten Rechtsmodells in Zweifel gezogen.
Im Jahre 2011 feierte der Slowakische Deutschlehrer- und Germanistenverband SUNG das zwanzigjährige Jubiläum seiner Gründung mit einer Reihe von Veranstaltungen, in denen er sowohl alle an der deutschen Sprache und der deutschsprachigen Kultur Interessierten als auch alle an ihrer Förderung und Erforschung Beteiligten zum Dialog einlud. Den Auftakt der Reihe bildete das wissenschaftliche Seminar zum Thema 20 Jahre Germanistik in der Slowakei“, das in Kooperation mit dem Lehrstuhl für Germanistik der Cyril und Methodius Universität in Trnava im Juni 2011 veranstaltet wurde und den Stand der germanistischen Forschung in der Slowakei gut zwei Jahrzehnte nach dem gesellschaftlichen Umbruch fokussierte. Im Heft 2/2011 veröffentlichte die Slowakische Zeitschrift für Germanistik den linguistischen Teil der retrospektiven Studien, die durch diese Initiative angeregt wurden.
Das Heft [...] bietet Raum zur Fortsetzung dieser Bilanz, indem es die Bereiche Literaturwissenschaft (mit den Schwerpunkten Schweizer Literatur, österreichische Literatur, DDR-Literatur, Komparatistik) und Translationswissenschaft (literarische Übersetzung, Übersetzungskritik, germanistische Translationswissenschaft in Banská Bystrica) in den Fokus rückt. Mehrere slowakische Literaturwissenschaftler und Übersetzungswissenschaftler, die der Einladung des Verbands folgten, bemühen sich in den hier publizierten Studien, die bisherige germanistische Forschung ihrer Themenfelder zu reflektieren und die fachlichen Entwicklungen seit dem Epocheneinschnitt geschichtlich einzuordnen. Jüngere Forscher nutzen dieses Forum, um die Leistungen von namhaften Vertretern der slowakischen germanistischen Literaturwissenschaft genauer in den Blick zu nehmen, sie neu zu hinterfragen und im geschichtlichen Kontext zu verorten. In allen Aufsätzen wird jedoch die Unabgeschlossenheit der Ausführungen zugegeben. Die Studien wenden sich ausgewählten Forschungsschwerpunkten zu und das Bild, das am Ende entsteht, muss ausschnitthaft und unvollständig bleiben. Die Beiträge dienen jedoch keineswegs der heute so häufigen Selbstinszenierung, sondern zeugen von Respekt vor der Leistung der anderen und sind das Ergebnis einer ehrlichen Bemühung um ihre Dokumentation.
An den Schnittpunkten der Fachgeschichte und der Forschungsgegenwart sollen auch aktuelle Fragestellungen aufgegriffen werden und zugleich Anregungen zu den Diskussionen um die Perspektiven der slowakischen Germanistik entstehen. Auf diese Weise möchte die Slowakische Zeitschrift für Germanistik einen Beitrag dazu leisten, bestehende wissenschaftliche Aktivitäten in der slowakischen Forschungslandschaft zu vernetzen und unterschiedliche, oft vereinzelte Forschungstrends der hiesigen Germanistik zu bündeln.
Biopharmazeutika sind heutzutage ein wichtiger Bestandteil des Arzneimittelmarktes. Ihr komplexer Aufbau und ihre Mikroheterogenität erfordern eine genaue strukturelle Charakterisierung auf verschiedenen Ebenen der Moleküle, wobei die Anwendung neuer Methoden von den entsprechenden Richtlinien durchaus erwünscht ist. Die Massenspektrometrie als Analysemethode hat sich in diesem Gebiet bereits fest etabliert. Verschiedenste massenspektrometrische Untersuchungen können an den intakten Biopharmazeutika sowie an größeren und kleineren Bruchstücken derselben durchgeführt werden. Trotzdem wird meist auf wenige, lange etablierte Protokolle zurückgegriffen, die häufig mit langwieriger Probenvorbereitung verbunden sind. Bei der Analyse der Glykosylierung wird immer noch die chromatographische Trennung mit anschließender Detektion durch UV- oder Fluoreszenzmessung bevorzugt.
In dieser Arbeit sollten die Möglichkeiten der Massenspektrometrie bei der Analyse von Biopharmazeutika genauer untersucht werden. Dazu gehört auch, den hohen Informationsgehalt der üblichen chromatographischen Auftrennung von Peptiden aus einem proteolytischen Verdau vollständig zu nutzen. Es wurde gezeigt, dass die manuelle Auswertung der Analyse zusätzliche Ergebnisse bringt, und dass gleichzeitig eine Analyse von posttranslationalen und prozessbedingten Modifikationen möglich ist. Zudem wurde der Verdau mit der Protease Trypsin auf das jeweilige Biopharmazeutikum und auf das Ziel der Analyse optimiert. Da mit Trypsin eine vollständige Sequenzabdeckung nicht erreichbar war, wurden zusätzlich verschiedene weniger spezifische Proteasen angewendet. Alle untersuchten weniger spezifischen Proteasen (Elastase, Chymotrypsin und Thermolysin) waren für eine solche Analyse gut geeignet. Die Komplementarität von MALDI- und ESI-MS-Analysen konnte durch ihre Kombination optimal ausgeschöpft werden. Zudem wurden weitere Methoden zur Erhöhung der Sequenzabdeckung wie die Derivatisierung der Peptide mit TMTzero vorgestellt.
Für die Analyse intakter Biopharmazeutika wurden neben der Größenausschlusschromatograph und gelelektrophoretischen Trennungen sowohl MALDI- als auch ESI-MS-Analysen verwendet. Die Trennung großer Proteinmoleküle in kleinere Untereinheiten erleichterte dabei die massenspektrometrische Analyse maßgeblich. Die Fragmentierung der Biopharmazeutika mittels MALDI-ISD war für die Bestimmung der Protein-N- und C-Termini sehr gut geeignet.
Die Analyse der Glykosylierung wurde an den freien N-Glykanen aus einem PNGaseF-Verdau sowie an Glykopeptiden aus einem Verdau mit Pronase durchgeführt. Die freien N-Glykane konnten zudem für die MALDI-MS-Analyse mit der MALDI-Matrix 3-Aminochinolin direkt auf dem Probenteller derivatisiert werden. Die Derivatisierung und Vermessung der N-Glykane wurde zunächst an verschiedenen Standardoligosacchariden, Humanmilcholigosacchariden und N-Glykanen aus Standardglykoproteinen optimiert. Durch die Fragmentierung der N-Glykane konnten diese sequenziert und isomere Strukturen unterschieden werden.
Bei einem Pronaseverdau wurden Proteine so weit verdaut, dass nur noch einzelne Aminosäuren bzw. Di- oder Tripeptide übrig blieben. Lediglich die Glykosylierungsstellen waren durch die voluminösen Glykanstrukturen vor dem Verdau geschützt und behielten eine kurze Peptidsequenz, die für eine Identifizierung der Glykosylierungsstelle ausreichend war. So konnten die N- und O-Glykopeptide direkt ohne Aufreinigung mittels MALDI-MS aus den Verdauansätzen analysiert werden, ohne dass nicht glykosylierte Peptide störten. Das Verdauprotokoll wurde zunächst an mehreren Standard-N- und -O-Glykoproteinen optimiert und anschließend auf die untersuchten Biopharmazeutika angewendet. N- und O-Glykopeptide konnten sogar nebeneinander analysiert werden. Die hohe Massengenauigkeit des verwendeten MALDI LTQ-Orbitrap Massenspektrometers ließ eine eindeutige Identifizierung der Glykopeptide mit Hilfe eines dafür entwickelten Programms zu. Weiterhin konnte die Identifizierung durch die Fragmentierung der Glykopeptide unterstützt werden.
Somit konnten in dieser Arbeit verschiedene massenspektrometrische Analysen von Biopharmazeutika neu entwickelt, optimiert oder vereinfacht werden. Dabei wurden für jede Strukturebene (intaktes Molekül, größere und kleinere Fragmente) sowohl Ansätze mit MALDI-MS als auch mit ESI-MS verfolgt. Einige Methoden, die in der Proteomforschung bereits Anwendung fanden, konnten erfolgreich auf Biopharmazeutika übertragen werden. Die Arbeit zeigt, dass die Massenspektrometrie ein großes Potential in der Analyse der Biopharmazeutika besitzt, das aber bisher noch nicht vollständig ausgeschöpft wird. Durch die Wahl der richtigen Methoden und der geeigneten Instrumentierung wird eine vollständige strukturelle Charakterisierung ermöglicht.
Die vorliegende Bachelorarbeit leistet einen Beitrag zur wissenschaftlichen Identifikation von intergenerationalen Unterschieden verschiedener Arbeitnehmergruppen. Insbesondere werden sowohl die Unterschiede zwischen den Generationen X und Y, in der Arbeitsbereitschaft, in unterschiedlichen Abschnitten des Berufslebens, als auch die Unterschiede zwischen der Wahrnehmung der Wichtigkeit von Arbeitgeberattraktivitätsattributen jener Generationen betrachtet. Ein besonderes Augenmerk liegt hierbei auf der Betrachtung von High-Potentials.
In der Atom- und Molekülphysik werden häufig Multichannelplate Detektoren mit Delay-Line-Auslese eingesetzt. Um eine große Präzision und eine hohe Reaktionsrate zu erhalten, ist es wichtig, dass alle Daten genau analysiert werden können. Die aktuelle Methode der Datenanalyse stößt dabei auf Probleme, wenn mehrere Teilchen kurz hintereinander auf den Detektor treffen. In dieser Arbeit wird versucht, ein neuronales Netz so zu trainieren, dass es eine bessere Datenanalyse liefert. Hierzu wird im ersten Kapitel der Detektoraufbau beschrieben, um zu verstehen, woher die einzelnen Signale kommen und wie sie zu interpretieren sind. Im zweiten Kapitel wird dann die Theorie vorgestellt, auf der neuronale Netze basieren. Das dritte Kapitel gibt einen kurzen Überblick über die benutzte Technik. Im vierten und fünften Kapitel werden die Ergebnisse dieser Arbeit vorgestellt. Im abschließenden sechsten Kapitel werden die Ergebnisse zusammengefasst und ein Ausblick auf weitere mögliche Projekte gegeben.
IWF aktuell : [Nr. 3] 2/1977
(1977)
IWF aktuell : [Nr. 9] 1/1981
(1981)
IWF aktuell : Nr. 17
(1987)
IWF aktuell : Nr. 20
(1992)
IWF aktuell : Nr. 21
(1992)
IWF aktuell : Nr. 28
(1998)
Construction and commissioning of a setup to study ageing phenomena in high rate gas detectors
(2014)
In high-rate heavy-ion experiments, gaseous detectors encounter big challenges in terms of degradation of their performance due to a phenomenon dubbed ageing. In this thesis, a setup for high precision ageing studies has been constructed and commissioned at the GSI detector laboratory. The main objective is the study of ageing phenomena evoked by materials used to build gaseous detectors for the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR).
The precision of the measurement, e.g., of the gain of a gaseous detector, is a key element in ageing studies: it allows to perform the measurement at realistic rates in an acceptable time span. It is well known the accelerating ageing employing high intensity sources might produce misleading results. The primary objective is to build an apparatus which allows very accurate measurements and is thus sensitive to minute degradations in detector performance. The construction and commissioning of the
setup has been carried out in two steps. During the first step of this work, a simpler setup which already existed in the detector laboratory of GSI had been utilised to define all conditions related to ageing studies. The outcome of these studies defined the properties and characteristics that must be met to build and operate a new, sophisticated and precise setup. The already existing setup consisted of two identical Multi Wire Proportional Chambers (MWPCs), a gas mixing station, an 55Fe source, an x-ray generator, an outgassing box and stainless steel tubing. In a first step, the gain and electric field configuration of the MWPCs were simulated by a combination of a gas simulation (Magboltz) and electric field simulation program (Garfield). The performance and operating conditions of the chambers have been thoroughly characterised before utilising them in first preparatory ageing test. The main diagnostic parameter in ageing studies is the detector gain, thus it is mandatory for precise ageing studies to minimise the systematic and statistical variation of the pressure and temperature corrected gain. To achieve the required accuracy, several improvements of the chamber design and the gas system have been implemented. In addition, the temperature measurement has been optimised. During the preparatory tests, several ageing studies have been carried out. The ageing effect of seven materials and gases have been carried out during these tests: RTV-3145, Ar/CO2 gas, Durostone flushed with Ar/Isobutane gas, Vetronit G11, Vetronit G11 contaminated with Micro 3000 and Gerband 705. The results of these studies went into the design of the new sophisticated ageing setup. For example some tests revealed that there was, even after cleaning, a certain level of contamination with "ageing agents" in the existing setup, which made it imperative to ensure a very high level cleanness of all components during the construction of the setup. The curing period of some testing samples like glues or the gas flow rate were found to be very important factors that must be taken into account to obtain comparable results. Very important changes in the chamber design have been made, i.e., the aluminium-Kapton cathodes used in MWPCs have been replaced with multi-wire planes and the fibreglass housing of the chamber has been changed to metal. The second step started with building the new setup which was designed based on the findings from the first step. The new ageing setup consists of three MWPCs, two moving platforms, an 55Fe source, a copper-anode x-ray generator, two outgassing boxes, both flexible and rigid stainless steel tubes. Before fabrication of the chambers, simulations of their electric field and the gain have been done using Magboltz and Garfield programs. After that, the chambers were installed and tested. A 0.3% peak-to-peak residual variation of the corrected gain has been achieved. Finally, the complete setup has been operated with full functionality in no-ageing conditions during one week. This test revealed very stable gain in all three chambers. After that two materials (Gerban 705 and RTV-3145) have been inserted in the two outgassing boxes and tested. They revealed an ageing rate of about 0.3%/mC/cm and 3%/mC/cm respectively. The final test proves the stability and accuracy of the ageing measurements carried out with the ageing setup at the detector laboratory at GSI which is ready to conduct the envisaged systematic ageing studies.
IWF aktuell : Nr. 24
(1994)
IWF aktuell : Nr. 25
(1995)
The fauna of Dynastinae (Scarabaeidae) on the island of Saba, Dutch Caribbean, was investigated through fi eldwork during 2006 to 2015. Three species, belonging to the three tribes Cyclocephalini, Pentodontini and Phileurini, are newly recorded from Saba and are discussed, with summaries of all relevant information from the West Indies. Detailed locality data, temporal distributions, and habitus photographs are presented for each species.
The checklist revealed 40 species of scale insects (Hemiptera: Coccoidea) intercepted at Korean ports of entry on dracaena and fi cus plants from southern Asia from 1996 to 2014. Brief diagnostic criteria and related information of the intercepted species are given to assist in the identifi cation of specimens of scale insects intercepted from these plant hosts. Additionally, this preliminary checklist of scale insects could be utilized as a basis for preventive measures in quarantine.
The Colombian fluted scale (CFS), Crypticerya multicicatrices Kondo & Unruh (Hemiptera: Monophlebidae) is a polyphagous scale insect which affects about 100 species of plants. Between 2010–2013, the species was reported as an invasive pest on the islands of San Andres and Old Providence, Colombian territory in the Caribbean sea.
Currently, populations of the CFS also have increased in the city of Cali, Valle del Cauca State, mainland Colombia, affecting different host plants, especially leguminous trees such as Caesalpinia peltophoroides Benth., Pithecellobium dulce (Roxb.) Benth., P. saman (Jacq.) Benth. (Fabaceae) and mango, Mangifera indica L. (Anacardiaceae). With the aim of searching for natural enemies to control the CFS, field studies were conducted in the city of Cali between February 2013 and October 2014. As a result of this study, two species of lady beetles were found feeding on CFS, i.e., Anovia punica Gordon and Rodolia cardinalis (Mulsant) (Coleoptera: Coccinellidae). This is the first record of R. cardinalis preying on CFS.
Erythemis Hagen, 1861 (Odonata: Libellulidae: Sympetrinae) is a Neotropical genus with ten species in which morphological characters vary widely. The aim of this paper is to study the taxonomic diversity of the genus Erythemis and to test the diagnostic value of morphological characters used to discriminate species. The diagnostic value of the morphometric characters is tested using discriminant function analysis, principal component analysis, and graphical exploration of the data. A total of 134 characters were studied; of those, 53 are recoded and 81 are proposed in this work. Discrete characters such as color, genitalia, ventral teeth of male cercus, extension of dark basal area in hind wing, and morphometric characters of abdominal carinae and antenodal wing venation are the most useful for species determination. In contrast, abdomen length/HW length ratio, vulvar lamina length, and spines of femoral structure are highly variable. A lectotype is designated for Diplax credula Hagen, 1861. Taxonomic keys for males and females are included, and variation in several characters is presented.
Lectotypes are designated for the following species-level taxa, based on specimens in the Museum of Comparative Zoology, Harvard University: Tetratomidae (Hallomenus scapularis Melsheimer, 1846; Hallomenus serricornis LeConte, 1878); Melandryidae (Hypulus bicinctus Horn, 1888; Dircaea liturata LeConte, 1866; Dircaea fusca LeConte, 1878; Dircaea prona LeConte, 1878; Dircaea riversi LeConte, 1884; Hypulus trifasciatus Melsheimer, 1846; Microtonus sericans LeConte, 1862; Scraptia fl avicollis Haldeman, 1848; Scraptia rugosa Haldeman, 1848; Melandrya maculata LeConte, 1850; Melandrya striata var. bicolor Melsheimer, 1846; Melandrya striata var.
thoracica Melsheimer, 1846; Hypulus fulminans LeConte, 1859; Microscapha arctica Horn, 1893; Microscapha clavicornis LeConte, 1866; Orchesia castanea Melsheimer, 1846; Orchesia gracilis Melsheimer, 1846; Orchesia ornata Horn, 1888; Amblyctis praeses LeConte, 1879; Dircaea sericea Haldeman, 1848; Serropalpus obsoletus Haldeman, 1848; Serropalpus substriatus Haldeman, 1848; Carebara longula LeConte, 1866; Hallomenus quadripustulata Melsheimer, 1846); Mycteridae (Mycterus canescens Horn, 1879; Mycterus quadricollis Horn, 1874); and Boridae (Crymodes discicollis LeConte, 1850).
At Topes de Collantes Natural Park, Alturas de Trinidad, in the mountains of Guamuhaya province of Sancti Spiritus, Cuba, 30 species of scale insects belonging to 21 genera, four families and an endemic species were identifi ed. Specimens were deposited at the insect zoological collection of the Ecology and Systematics Institute (CZACC), Cuba. A literature review was carried out and the world data base on scale insects, ScaleNet was consulted. A cartographic map indicating the collecting sites at the scale of 1: 250,000 was created using MapInfo Professional Version 4.5 program. Twelve species are recorded for the fi rst time for the mountains of Guamuhaya and further 10 species are recorded for other locations. 82% of the species were polyphagous, 11% were oligophagous and 7% were monophagous. 57% were introduced species, 43% were native and 79% are cosmopolitan or widely distributed species. 30 species and 21 families of host plants were identifi ed, of which 23 plant species were new host plant records for 19 scale insect species, and 11 botanical families are for the fi rst time recorded as hosts for 10 scale insect species. There were signifi cant differences in the distribution of scale insects and their host plant species, botanical families and vegetation type.