3,016 research outputs found
Paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial Krems-Wachtberg record (NE Austria)
The complex interplay of dust sedimentation, pedogenesis, and erosion/reworking in the formation of loess-paleosol sequences (LPS) challenges paleoenvironmental proxies. Here we show that color and grain size are essential parameters characterizing loess profiles and support robust stratigraphies as a basis for reconstructions in the context of local geo-ecological and large-scale paleoclimatic evolution. Detailed paleoenvironmental records from the period since the arrival of anatomically modern humans to the last glacial maximum are scarce in the Alpine surroundings. The c. 7.5 m thick LPS Krems-Wachtberg, NE Austria, known for its well-preserved Upper Paleolithic context at a depth of 5.5 m, formed between 40 and 20 ka BP by quasi-continuous dust-sedimentation, interrupted by phases of incipient pedogenesis and local reworking. The new KW2015 composite is based on three sections studied and sampled at 2.5 cm resolution. Color and grain size data support a robust stratigraphy for reconstructions of the pedosedimentary evolution. The marked transition from oxidized to reduced paleosols of KW2015 around 34â35 ka corresponds to the Middle-to Upper Pleniglacial transition as part of a general cooling trend from marine isotope stage (MIS) 3 to 2, intensely modulated by millennial-scale climatic fluctuations as recorded in the Greenland ice core data. The distinct response of KW2015 to these trends highlights that reconstructing LPS evolution based on a robust stratigraphy is a prerequisite to paleoenvironmental proxy interpretation
B cell fate mapping reveals their contribution to the memory immune response against helminths
An estimated quarter of the human world population is infected with gastrointestinal helminths causing major socioeconomic problems in endemic countries. A better understanding of humoral immune responses against helminths is urgently needed to develop effective vaccination strategies. Here, we used a fate mapping (FM) approach to mark germinal center (GC) B cells and their developmental fates by induced expression of a fluorescent protein during infection of mice with the helminth Nippostrongylus brasiliensis. We could show that FM+ cells persist weeks after clearance of the primary infection mainly as CD80+CD73+PD-L2+ memory B cells. A secondary infection elicited expansion of helminth-specific memory B cells and plasma cells (PCs). Adoptive transfers and analysis of somatic mutations in immunoglobulin genes further revealed that FM+ B cells rapidly convert to PCs rather than participating again in a GC reaction. These results provide new insights in the population dynamics of the humoral immune response against helminths
Increased Incidence of Perforated Appendicitis in Children During COVID-19 Pandemic in a Bavarian Multi-Center Study
Introduction: Since early 2020 the COVID-19 pandemic and statutory preventive reorganization of treatment capacities with cancellation of elective surgery as well as curfew regulations led to vastly decreased utilization of primary health care.
Materials and Methods: To assess whether there are negative effects on pediatric acute care in Bavaria during the spring 2020 lockdown a state-wide retrospective multi-center study was performed to analyze the rate of perforated appendicitis during lockdown. Children who have been operated on during the corresponding period in 2018/19 served as control group.
Results: Overall, 514 patients (292 boys, 222 girls) were included (2020: 176 patients; 2019: 181 patients; 2018: 157 patients). Median age was 11.2 years. Four hundred thirty-nine patients (85.4%) underwent laparoscopic surgery, 69 (13.4%) open surgery and 1.2% underwent conversion from laparoscopic to open surgery. In 2020 a perforation rate of 27.8% (49/176 patients) was found, in 2018â2019 perforation rate was 20.7% (70/338 patients, p = 0.0359, Cochran-Mantel-Haenszel-Test). Subgroup analysis showed that in younger patients (†11.2 years), in 2020 perforation rate was significantly higher with 37.6% (32/85 patients), while 22.2% (39/176) in 2018/2019 (p = 0.014, Fisher's exact test).In boys perforation rate was significantly higher in 2020 with 35.0% (35/100 patients) compared to 21.4% in 2018â2019 (p = 0.0165, Fisher's exact test).
Conclusion: During the period of curfew regulations in Bavaria the rate of perforated appendicitis in childhood increased significantly, especially in younger children and boys. Potentially this has to be attributed to delayed presentation to pediatric surgery care. Because of potential long-term sequelae of perforated appendicitis these adverse effects during curfew have to be taken into account for future political decision making to ensure reasonable patient care and avoid collateral damage in near-future or on-going pandemic situations
Mellin moments of spin dependent and independent PDFs of the pion and rho meson
We compute the second moments of pion and rho parton distribution functions in lattice QCD with Nf=2+1 flavors of improved Wilson fermions. We determine both singlet and nonsinglet flavor combinations and, for the first time, take disconnected contributions fully into account. In the case of the rho, we also calculate the additional contribution arising from the b1 structure function. The numerical analysis includes 26 ensembles, mainly generated by the CLS effort, with pion masses ranging from 420 down to 214 MeV and with 5 different lattice spacings in the range of 0.1 to 0.05 fm. This enables us to take the continuum limit, as well as to resolve the quark mass dependencies reliably. Additionally we discuss the contaminations of rho correlation functions by two-pion states
Handbuch methodischer Grundfragen zur Masterplan-Erstellung - Kommunale MasterplĂ€ne fĂŒr 100 % Klimaschutz
Masterplan-Kommunen sind die Vorreiter unter den Klimaschutzkommunen und mĂŒssen ĂŒber das bisher
in der Breite bereits Begonnene hinausgehen. Sie stehen vor groĂen strukturellen und finanziellen
Herausforderungen, aber auch vor groĂen Chancen. Die Chancen ergeben sich insbesondere fĂŒr ein
verbessertes und lebenswerteres Umfeld in der Kommune und damit auch fĂŒr eine gesteigerte LebensqualitĂ€t.
Die Einbindung aller Akteure in der Kommune, innerhalb und auĂerhalb der Verwaltung, ist
ein wichtiger Baustein auf dem Weg zum Ziel âNull Emissionenâ. Vor allem die Einbindung der Wirtschaft
vor Ort und der BĂŒrgerinnen und BĂŒrger ist essenziell, wenn eine Transformation angestoĂen
und umgesetzt werden soll. Das Handbuch unterstĂŒtzt die Masterplan-Kommunen mit der vorliegenden
methodischen Herangehensweise auf ihrem Weg
The removal of shear-ellipticity correlations from the cosmic shear signal: Influence of photometric redshift errors on the nulling technique
Cosmic shear is regarded one of the most powerful probes to reveal the
properties of dark matter and dark energy. To fully utilize its potential, one
has to be able to control systematic effects down to below the level of the
statistical parameter errors. Particularly worrisome in this respect is
intrinsic alignment, causing considerable parameter biases via correlations
between the intrinsic ellipticities of galaxies and the gravitational shear,
which mimic lensing. In an earlier work we have proposed a nulling technique
that downweights this systematic, only making use of its well-known redshift
dependence. We assess the practicability of nulling, given realistic conditions
on photometric redshift information. For several simplified intrinsic alignment
models and a wide range of photometric redshift characteristics we calculate an
average bias before and after nulling. Modifications of the technique are
introduced to optimize the bias removal and minimize the information loss by
nulling. We demonstrate that one of the presented versions is close to optimal
in terms of bias removal, given high quality of photometric redshifts. For
excellent photometric redshift information, i.e. at least 10 bins with a small
dispersion, a negligible fraction of catastrophic outliers, and precise
knowledge about the redshift distributions, one version of nulling is capable
of reducing the shear-intrinsic ellipticity contamination by at least a factor
of 100. Alternatively, we describe a robust nulling variant which suppresses
the systematic signal by about 10 for a very broad range of photometric
redshift configurations. Irrespective of the photometric redshift quality, a
loss of statistical power is inherent to nulling, which amounts to a decrease
of the order 50% in terms of our figure of merit.Comment: 26 pages, including 16 figures; minor changes to match accepted
version; published in Astronomy and Astrophysic
Simultaneous measurement of cosmology and intrinsic alignments using joint cosmic shear and galaxy number density correlations
Cosmic shear is a powerful method to constrain cosmology, provided that any
systematic effects are under control. The intrinsic alignment of galaxies is
expected to severely bias parameter estimates if not taken into account. We
explore the potential of a joint analysis of tomographic galaxy ellipticity,
galaxy number density, and ellipticity-number density cross-correlations to
simultaneously constrain cosmology and self-calibrate unknown intrinsic
alignment and galaxy bias contributions. We treat intrinsic alignments and
galaxy biasing as free functions of scale and redshift and marginalise over the
resulting parameter sets. Constraints on cosmology are calculated by combining
the likelihoods from all two-point correlations between galaxy ellipticity and
galaxy number density. The information required for these calculations is
already available in a standard cosmic shear dataset. We include contributions
to these functions from cosmic shear, intrinsic alignments, galaxy clustering
and magnification effects. In a Fisher matrix analysis we compare our
constraints with those from cosmic shear alone in the absence of intrinsic
alignments. For a potential future large area survey, such as Euclid, the extra
information from the additional correlation functions can make up for the
additional free parameters in the intrinsic alignment and galaxy bias terms,
depending on the flexibility in the models. For example, the Dark Energy Task
Force figure of merit is recovered even when more than 100 free parameters are
marginalised over. We find that the redshift quality requirements are similar
to those calculated in the absence of intrinsic alignments.Comment: 22 pages, 10 figures; extended discussion, otherwise minor changes to
match accepted version; published in Astronomy and Astrophysic
On DABAL-Meâ promoted formation of amides
The range and utility of DABAL-Me3 couplings of methyl esters and free carboxylic acids with primary and secondary amines under a variety of conditions (reflux, sealed tube, microwave) has been compared for a significant range of coupling partners of relevance to the preparation of amides of interest in pharmaceutical chemistry. Commercial microwave reactors promote the fastest couplings and allow the use of significantly sterically hindered amines (primary and secondary) and carboxylic acids derivatives. The influence of microwave energy on the reaction system was shown to be typically related to thermal effects (over-pressuring and superheating)
The inhibitory receptor SiglecâG controls the severity of chronic lymphocytic leukemia
Chronic Lymphocytic Leukemia (CLL) is the most common leukemia in adults in the Western world. B cell receptor (BCR) signaling is known to be crucial for the pathogenesis and maintenance of CLL cells which develop from mature CD5+ B cells. BCR signaling is regulated by the inhibitory coâreceptor SiglecâG and SiglecâGâdeficient mice have an enlarged CD5+ B1a cell population. Here, we determine how SiglecâG expression influences the severity of CLL. Our results show that SiglecâG deficiency leads to earlier onset and more severe course of the CLLâlike disease in the murine EÎŒâTCL1 model. In contrast, mice overexpressing SiglecâG on the B cell surface are almost completely protected from developing CLLâlike disease. Furthermore, we observe a downmodulation of the human ortholog Siglecâ10 from the surface of human CLL cells. These results demonstrate a critical role for SiglecâG in disease progression in mice, and suggest that a similar mechanism for Siglecâ10 in human CLL may exist.Synopsis image Deficiency of the inhibitory receptor SiglecâG in mice leads to earlier onset and more severe chronic lymphocytic leukemia (CLL). In contrast, overexpression of SiglecâG on B cells protects mice from CLL. Deficiency of SiglecâG in a mouse model leads to more severe chronic lymphocytic leukemia. Mice overexpressing SiglecâG on the B cell surface are protected from CLL disease. Siglecâ10, the human ortholog to SiglecâG, is downâmodulated on CLL cells of human patients. Deficiency of the inhibitory receptor SiglecâG in mice leads to earlier onset and more severe chronic lymphocytic leukemia (CLL). In contrast, overexpression of SiglecâG on B cells protects mice from CLL. image Deutsche Forschungsgemeinschaft (DFG
Changes of hemodynamic and cerebral oxygenation after exercise in normobaric and hypobaric hypoxia: associations with acute mountain sickness
Objective: Normobaric (NH) and hypobaric hypoxia (HH) are associated with acute mountain sickness (AMS) and cognitive dysfunction. Only few variables, like heart-rate-variability, are correlated with AMS. However, prediction of AMS remains difficult. We therefore designed an expedition-study with healthy volunteers in NH/HH to investigate additional non-invasive hemodynamic variables associated with AMS.Methods: Eleven healthy subjects were examined in NH (FiO(2) 13.1%;equivalent of 3.883m a.s.l;duration 4h) and HH (3.883ma.s.l.;duration 24h) before and after an exercise of 120min. Changes in parameters of electrical cardiometry (cardiac index (CI), left-ventricular ejection time (LVET), stroke volume (SV), index of contractility (ICON)), near-infrared spectroscopy (cerebral oxygenation, rScO(2)), Lake-Louise-Score (LLS) and cognitive function tests were assessed. One-Way-ANOVA, Wilcoxon matched-pairs test, Spearman's-correlation-analysis and Student's t-test were performed.Results: HH increased heart rate (HR), mean arterial pressure (MAP) and CI and decreased LVET, SV and ICON, whereas NH increased HR and decreased LVET. In both NH and HH cerebral oxygenation decreased and LLS increased significantly. After 24h in HH, 6 of 11 subjects (54.6%) developed AMS. LLS remained increased until 24h in HH, whereas cognitive function remained unaltered. In HH, HR and LLS were inversely correlated (r=-0.692;p<0.05). More importantly, the rScO2-decrease after exercise in NH significantly correlated with LLS after 24h in HH (r=-0.971;p<0.01) and rScO2 correlated significantly with HR (r=0.802;p<0.01), CI (r=0.682;p<0.05) and SV (r=0.709;p<0.05) after exercise in HH.Conclusion: sBoth acute NH and HH altered hemodynamic and cerebral oxygenation and induced AMS. Subjects, who adapted their CI had higher rScO2 and lower LLS. Furthermore, rScO2 after exercise under normobaric conditions was associated with AMS at high altitudes
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