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Driven by the loss of energy, isolated rotating neutron stars (pulsars) are gradually slowing down to lower frequencies, which increases the tremendous compression of the matter inside of them. This increase in compression changes both the global properties of rotating neutron stars as well as their hadronic core compositions. Both effects may register themselves observationally in the thermal evolution of such stars, as demonstrated in this Letter. The rotation-driven particle process which we consider here is the direct Urca (DU) process, which is known to become operative in neutron stars if the number of protons in the stellar core exceeds a critical limit of around 11% to 15%. We find that neutron stars spinning down from moderately high rotation rates of a few hundred Hertz may be creating just the right conditions where the DU process becomes operative, leading to an observable effect (enhanced cooling) in the temperature evolution of such neutron stars. As it turns out, the rotation-driven DU process could explain the unusual temperature evolution observed for the neutron star in Cas A, provided the mass of this neutron star lies in the range of 1.5 to 1.9M⊙ and its rotational frequency at birth was between 40 (400 Hz) and 70% (800 Hz) of the Kepler (mass shedding) frequency, respectively.
Paging is one of the most prominent problems in the field of online algorithms. We have to serve a sequence of page requests using a cache that can hold up to k pages. If the currently requested page is in cache we have a cache hit, otherwise we say that a cache miss occurs, and the requested page needs to be loaded into the cache. The goal is to minimize the number of cache misses by providing a good page-replacement strategy. This problem is part of memory-management when data is stored in a two-level memory hierarchy, more precisely a small and fast memory (cache) and a slow but large memory (disk). The most important application area is the virtual memory management of operating systems. Accessed pages are either already in the RAM or need to be loaded from the hard disk into the RAM using expensive I/O. The time needed to access the RAM is insignificant compared to an I/O operation which takes several milliseconds.
The traditional evaluation framework for online algorithms is competitive analysis where the online algorithm is compared to the optimal offline solution. A shortcoming of competitive analysis consists of its too pessimistic worst-case guarantees. For example LRU has a theoretical competitive ratio of k but in practice this ratio rarely exceeds the value 4.
Reducing the gap between theory and practice has been a hot research issue during the last years. More recent evaluation models have been used to prove that LRU is an optimal online algorithm or part of a class of optimal algorithms respectively, which was motivated by the assumption that LRU is one of the best algorithms in practice. Most of the newer models make LRU-friendly assumptions regarding the input, thus not leaving much room for new algorithms.
Only few works in the field of online paging have introduced new algorithms which can compete with LRU as regards the small number of cache misses.
In the first part of this thesis we study strongly competitive randomized paging algorithms, i.e. algorithms with optimal competitive guarantees. Although the tight bound for the competitive ratio has been known for decades, current algorithms matching this bound are complex and have high running times and memory requirements. We propose the algorithm OnlineMin which processes a page request in O(log k/log log k) time in the worst case. The best previously known solution requires O(k^2) time.
Usually the memory requirement of a paging algorithm is measured by the maximum number of pages that the algorithm keeps track of. Any algorithm stores information about the k pages in the cache. In addition it can also store information about pages not in cache, denoted bookmarks. We answer the open question of Bein et al. '07 whether strongly competitive randomized paging algorithms using only o(k) bookmarks exist or not. To do so we modify the Partition algorithm of McGeoch and Sleator '85 which has an unbounded bookmark complexity, and obtain Partition2 which uses O(k/log k) bookmarks.
In the second part we extract ideas from theoretical analysis of randomized paging algorithms in order to design deterministic algorithms that perform well in practice. We refine competitive analysis by introducing the attack rate
parameter r, which ranges between 1 and k. We show that r is a tight bound on the competitive ratio of deterministic algorithms.
We give empirical evidence that r is usually much smaller than k and thus r-competitive algorithms have a reasonable performance on real-world traces. By introducing the r-competitive priority-based algorithm class OnOPT we obtain a collection of promising algorithms to beat the LRU-standard. We single out the new algorithm RDM and show that it outperforms LRU and some of its variants on a wide range of real-world traces.
Since RDM is more complex than LRU one may think at first sight that the gain in terms of lowering the number of cache misses is ruined by high runtime for processing pages. We engineer a fast implementation of RDM, and compare it
to LRU and the very fast FIFO algorithm in an overall evaluation scheme, where we measure the runtime of the algorithms and add penalties for each cache miss.
Experimental results show that for realistic penalties RDM still outperforms these two algorithms even if we grant the competitors an idealistic runtime of 0.
BACKGROUND: Plasminogen deficiency is a rare autosomal recessive disease, which is associated with aggressive periodontitis and gingival enlargement. Previously described treatments of plasminogen deficiency associated periodontitis have shown limited success. This is the first case report indicating a successful therapy approach consisting of a non-surgical supra- and subgingival debridement in combination with an adjunctive systemic antibiotic therapy and a strict supportive periodontal regimen over an observation period of 4 years.
CASE PRESENTATION: The intraoral examination of a 17-year-old Turkish female with severe plasminogen deficiency revealed generalized increased pocket probing depths ranging from 6 to 9 mm, bleeding on probing over 30%, generalized tooth mobility, and gingival hyperplasia. Alveolar bone loss ranged from 30% to 50%. Clinical attachment loss corresponded to pocket probing depths. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Prevotella nigrescens and Eikenella corrodens have been detected by realtime polymerase chain reaction. Periodontal treatment consisted of full mouth disinfection and adjunctive systemic administration of amoxicillin (500 mg tid) and metronidazole (400 mg tid). A strict supportive periodontal therapy regimen every three month in terms of supra- and subgingival debridement was rendered. The reported therapy has significantly improved periodontal health and arrested disease progression. Intraoral examination at the end of the observation period 3.5 years after non-surgical periodontal therapy showed generalized decreased pocket probing depths ranging from 1 to 6 mm, bleeding on probing lower 30%, and tooth mobility class I and II. Furthermore, microbiological analysis shows the absence of Porphyromonas gingivalis, Prevotella intermedia and Treponema denticola after therapy.
CONCLUSION: Adjunctive antibiotic treatment may alter the oral microbiome and thus, the inflammatory response of periodontal disease associated to plasminogen deficiency and diminishes the risk of pseudomembrane formation and progressive attachment loss. This case report indicates that patients with plasminogen deficiency may benefit from non-surgical periodontal treatment in combination with an adjunctive antibiotic therapy and a strict supportive periodontal therapy regimen.
Introduction: Cell salvage (CS) is an integral part of patient blood management (PBM) and aims to reduce allogeneic red blood cell (RBC) transfusion.
Material and methods: This observational study analysed patients scheduled for elective cardiac surgery requiring cardiopulmonary bypass (CPB) between November 2015 and October 2018. Patients were divided into a CS group (patients receiving CS) and a control group (no CS). Primary endpoints were the number of patients exposed to allogeneic RBC transfusions and the number of RBC units transfused per patient.
Results: A total of 704 patients undergoing cardiac surgery were analysed, of whom 338 underwent surgery with CS (CS group) and 366 were without CS (control group). Intraoperatively, 152 patients (45%) were exposed to allogeneic RBC transfusions in the CS group and 93 patients (25%) in the control group (P < 0.001). Considering the amount of intraoperative blood loss, regression analysis revealed a significant association between blood loss and increased use of RBC units in patients of the control compared to the CS group (1000 mL: 1.0 vs. 0.6 RBC units; 2000 mL: 2.2 vs. 1.1 RBC units; 3000 mL: 3.4 vs. 1.6 RBC units). Thus, CS was significantly associated with a reduced number of allogeneic RBCs by 40% for 1000 mL, 49% for 2000 mL, and 52% for 3000 mL of blood loss compared to patients without CS.
Conclusions: Cell salvage was significantly associated with a reduced number of allogeneic RBC transfusions. It supports the beneficial effect of CS in cardiac surgical patients as an individual measure in a comprehensive PBM program.
Background: Iron deficiency (ID) is one of the most common nutritional deficiencies in children worldwide and may result in iron deficiency anemia (IDA). The reticulocyte hemoglobin equivalent (Ret-He) provides information about the current availability of iron in erythropoiesis. This study aims to examine the validation of Ret-He as a screening marker for ID and IDA in children. Methods: Blood samples were retrospectively obtained from medical records. Anemia was defined according to the definition provided by the World Health Organization (WHO) for children. ID was defined by transferrin saturation (TSAT) < 20% and ferritin < 100 ng/mL. Children were classified into four groups: IDA, non-anemia iron deficiency (NAID), control and others. Results: Out of 970 children, 332 (34.2%) had NAID and 278 (28.7%) presented with IDA. Analysis revealed that Ret-He significantly correlates with ferritin (rho = 0.41; p < 0.001), TSAT (rho = 0.66; p < 0.001) and soluble transferrin receptor (sTfR) (rho = −0.72; p < 0.001). For ROC analysis, the area under the curve (AUC) was 0.771 for Ret-He detecting ID and 0.845 for detecting IDA. The cut-off value for Ret-He to diagnose ID was 33.5 pg (sensitivity 90.7%; specificity 35.8%) and 31.6 pg (sensitivity 90.6%; specificity 50.4%) to diagnose IDA. Conclusions: The present study demonstrates Ret-He to be a screening marker for ID and IDA in children. Furthermore, Ret-He can be used as a single screening parameter for ID and IDA in children without considering other iron parameters. Economically, the use of Ret-He is highly relevant, as it can save one blood tube per patient and additional costs.
Background: Approximately one in three patients suffers from preoperative anaemia. Even though haemoglobin is measured before surgery, anaemia management is not implemented in every hospital. Objective: Here, we demonstrate the implementation of an anaemia walk-in clinic at an Orthopedic University Hospital. To improve the diagnosis of iron deficiency (ID), we examined whether reticulocyte haemoglobin (Ret-He) could be a useful additional parameter. Material and Methods: In August 2019, an anaemia walk-in clinic was established. Between September and December 2019, major orthopaedic surgical patients were screened for preoperative anaemia. The primary endpoint was the incidence of preoperative anaemia. Secondary endpoints included Ret-He level, red blood cell (RBC) transfusion rate, in-hospital length of stay and anaemia at hospital discharge. Results: A total of 104 patients were screened for anaemia. Preoperative anaemia rate was 20.6%. Intravenous iron was supplemented in 23 patients. Transfusion of RBC units per patient (1.7 ± 1.2 vs. 0.2 ± 0.9; p = 0.004) and hospital length of stay (13.1 ± 4.8 days vs. 10.6 ± 5.1 days; p = 0.068) was increased in anaemic patients compared to non-anaemic patients. Ret-He values were significantly lower in patients with ID anaemia (33.3 pg [28.6–40.2 pg]) compared to patients with ID (35.3 pg [28.9–38.6 pg]; p = 0.015) or patients without anaemia (35.4 pg [30.2–39.4 pg]; p = 0.001). Conclusion: Preoperative anaemia is common in orthopaedic patients. Our results proved the feasibility of an anaemia walk-in clinic to manage preoperative anaemia. Furthermore, our analysis supports the use of Ret-He as an additional parameter for the diagnosis of ID in surgical patients.
Background: Transfusion of red blood cells (RBC) in patients undergoing major elective cranial surgery is associated with increased morbidity, mortality and prolonged hospital length of stay (LOS). This retrospective single center study aims to identify the impact of RBC transfusions on skull-base and non-skull-base meningioma patients including the identification of risk factors for RBC transfusion.
Methods: From October 2009 - October 2016 we retrospectively analyzed 423 primary meningioma patients undergoing surgery for primary meningioma resection our department.
Results: Of these 423 patients, 68 (16.1%) received RBC transfusion and 355 (83.9%) did not receive RBC units. Preoperative anaemia rate was significantly higher in transfused patients (17.7%) compared to patients without RBC transfusion (6.2%; p = 0.0015). In transfused patients, postoperative complications as well as hospital LOS was significantly higher (p < 00001) compared to non-transfused patients. After multivariate analyses, risk factors for RBC transfusion were preoperative American Society of Anesthesiologists (ASA) physical status score (p = 0.0247), tumor size (p = 0.0006), surgical time (p = 0.0018) and intraoperative blood loss (p < 0.001). Kaplan-Meier curves revealed significant influence on overall survival by preoperative anaemia, RBC transfusion, smoking, cardiovascular disease, preoperative KPS ≤ 60% and age (elderly ≥ 75 years).
Conclusion: We concluded that blood loss due to large tumors or localization near large vessels are the main triggers for RBC transfusion in meningioma patients paired with a potential preselection that masks the effect of preoperative anaemia in multivariate analysis. Further studies evaluating the impact of preoperative anaemia management for reduction of RBC transfusion are needed to improve clinical outcomes of meningioma patients.
Transfusion of red blood cells (RBC) in patients undergoing major elective cranial surgery is associated with increased morbidity, mortality and prolonged hospital length of stay (LOS). This retrospective single center study aims to identify the clinical outcome of RBC transfusions on skull base and non-skull base meningioma patients including the identification of risk factors for RBC transfusion. Between October 2009 and October 2016, 423 patients underwent primary meningioma resection. Of these, 68 (16.1%) received RBC transfusion and 355 (83.9%) did not receive RBC units. Preoperative anaemia rate was significantly higher in transfused patients (17.7%) compared to patients without RBC transfusion (6.2%; p = 0.0015). In transfused patients, postoperative complications as well as hospital LOS was significantly higher (p < 0.0001) compared to non-transfused patients. After multivariate analyses, risk factors for RBC transfusion were preoperative American Society of Anaesthesiologists (ASA) physical status score (p = 0.0247), tumor size (p = 0.0006), surgical time (p = 0.0018) and intraoperative blood loss (p < 0.0001). Kaplan-Meier curves revealed significant influence on overall survival by preoperative anaemia, RBC transfusion, smoking, cardiovascular disease, preoperative KPS ≤ 60% and age (elderly ≥ 75 years). We concluded that blood loss due to large tumors or localization near large vessels are the main triggers for RBC transfusion in meningioma patients paired with a potential preselection that masks the effect of preoperative anaemia in multivariate analysis. Further studies evaluating the impact of preoperative anaemia management for reduction of RBC transfusion are needed to improve the clinical outcome of meningioma patients.
Characterization of neonates born to mothers with SARS-CoV-2 infection: review and meta-analysis
(2020)
Characterization of neonates born to mothers with SARS-CoV-2 infection has been partially carried out. There has been no systematic review providing a holistic neonatal presentation including possible vertical transmission. A systematic literature search was performed using PubMed, Google Scholar and Web of Science up to June, 6 2020. Studies on neonates born to mothers with SARS-CoV-2 infection were included. A binary random effect model was used for prevalence and 95% confidence interval. 32 studies involving 261 neonates were included in meta-analysis. Most neonates born to infected mothers did not show any clinical abnormalities (80.4%). Clinical features were dyspnea in 11 (42.3%) and fever in 9 newborns (19.1%). Of 261 neonates, 120 neonates were tested for infection, of whom 12 (10.0%) tested positive. Swabs from placenta, cord blood and vaginal secretion were negative. Neonates are mostly non affected by the mother's SARS-CoV-2 infection. The risk of vertical transmission is low.