17,088 research outputs found
Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Hrsg.): Finanzierungsmöglichkeiten für Naturschutzmaßnahmen : Stand: Oktober 2004
Erst die Umsetzung der zahlreichen bestehenden Planungen und Ideen kann positive Folgen für den Naturschutz bedrohter Arten und deren Lebensräume nach sich ziehen. Die Durchführung solcher Maßnahmen kostet aber viel Geld, das den Akteuren häufig fehlt. Trotz geschmälerter öffentlicher Haushalte ist die Chance für das Auffinden von Geldquellen aber gar nicht so schlecht, wie das „Finanzierungshandbuch für Naturschutzmaßnahmen“ des Bundesministeriums für Umwelt, Naturschutz und Reaktorsicherheit erkennen lässt
NAUTILUS: boosting Bayesian importance nested sampling with deep learning
We introduce a novel approach to boost the efficiency of the importance
nested sampling (INS) technique for Bayesian posterior and evidence estimation
using deep learning. Unlike rejection-based sampling methods such as vanilla
nested sampling (NS) or Markov chain Monte Carlo (MCMC) algorithms, importance
sampling techniques can use all likelihood evaluations for posterior and
evidence estimation. However, for efficient importance sampling, one needs
proposal distributions that closely mimic the posterior distributions. We show
how to combine INS with deep learning via neural network regression to
accomplish this task. We also introduce NAUTILUS, a reference open-source
Python implementation of this technique for Bayesian posterior and evidence
estimation. We compare NAUTILUS against popular NS and MCMC packages, including
EMCEE, DYNESTY, ULTRANEST and POCOMC, on a variety of challenging synthetic
problems and real-world applications in exoplanet detection, galaxy SED fitting
and cosmology. In all applications, the sampling efficiency of NAUTILUS is
substantially higher than that of all other samplers, often by more than an
order of magnitude. Simultaneously, NAUTILUS delivers highly accurate results
and needs fewer likelihood evaluations than all other samplers tested. We also
show that NAUTILUS has good scaling with the dimensionality of the likelihood
and is easily parallelizable to many CPUs.Comment: 15 pages, 10 figures, submitted to MNRAS; code available at
https://github.com/johannesulf/nautilu
Constraints on Assembly Bias from Galaxy Clustering
We constrain the newly-introduced decorated Halo Occupation Distribution
(HOD) model using SDSS DR7 measurements of projected galaxy clustering or
r-band luminosity threshold samples. The decorated HOD is a model for the
galaxy-halo connection that augments the HOD by allowing for the possibility of
galaxy assembly bias: galaxy luminosity may be correlated with dark matter halo
properties besides mass, Mvir. We demonstrate that it is not possible to rule
out galaxy assembly bias using DR7 measurements of galaxy clustering alone.
Moreover, galaxy samples with Mr < -20 and Mr < -20.5 favor strong central
galaxy assembly bias. These samples prefer scenarios in which
high-concentration are more likely to host a central galaxy relative to
low-concentration halos of the same mass. We exclude zero assembly bias with
high significance for these samples. Satellite galaxy assembly bias is
significant for the faintest sample, Mr < -19. We find no evidence for assembly
bias in the Mr < -21 sample. Assembly bias should be accounted for in galaxy
clustering analyses or attempts to exploit galaxy clustering to constrain
cosmology. In addition to presenting the first constraints on HOD models that
accommodate assembly bias, our analysis includes several improvements over
previous analyses of these data. Therefore, our inferences supersede
previously-published results even in the case of a standard HOD analysis.Comment: 15 pages, 8 figures. To be submitted to MNRAS. Comments Welcome.
Python scripts to perform this analysis and MCMC chains will all be made
publicly availabl
Maturing Satellite Kinematics into a Competitive Probe of the Galaxy-Halo Connection
The kinematics of satellite galaxies moving in a dark matter halo are a
direct probe of the underlying gravitational potential. Thus, the phase-space
distributions of satellites represent a powerful tool to determine the
galaxy-halo connection from observations. By stacking the signal of a large
number of satellite galaxies this potential can be unlocked even for haloes
hosting a few satellites on average. In this work, we test the impact of
various modelling assumptions on constraints derived from analysing satellite
phase-space distributions in the non-linear, 1-halo regime. We discuss their
potential to explain the discrepancy between average halo masses derived from
satellite kinematics and gravitational lensing previously reported.
Furthermore, we develop an updated, more robust analysis to extract constraints
on the galaxy-halo relation from satellite properties in spectroscopic galaxy
surveys such as the SDSS. We test the accuracy of this approach using a large
number of realistic mock catalogues. Furthermore, we find that constraints
derived from such an analysis are complementary and competitive with respect to
the commonly used galaxy clustering and galaxy-galaxy lensing observables.Comment: 24 pages, 15 figures; resubmitted to MNRAS after first referee repor
Updated Results on the Galaxy-Halo Connection from Satellite Kinematics in SDSS
We present new results on the relationship between central galaxies and dark
matter haloes inferred from observations of satellite kinematics in the Sloan
Digital Sky Survey (SDSS) DR7. We employ an updated analysis framework that
includes detailed mock catalogues to model observational effects in SDSS. Our
results constrain the colour-dependent conditional luminosity function (CLF) of
dark matter haloes, as well as the radial profile of satellite galaxies.
Confirming previous results, we find that red central galaxies live in more
massive haloes than blue galaxies at fixed luminosity. Additionally, our
results suggest that satellite galaxies have a radial profile less centrally
concentrated than dark matter but not as cored as resolved subhaloes in dark
matter-only simulations. Compared to previous works using satellite kinematics
by More et al., we find much more competitive constraints on the galaxy-halo
connection, on par with those derived from a combination of galaxy clustering
and galaxy-galaxy lensing. We compare our results on the galaxy-halo connection
to other studies using galaxy clustering and group catalogues, showing very
good agreement between these different techniques. We discuss future
applications of satellite kinematics in the context of constraining cosmology
and the relationship between galaxies and dark matter haloes.Comment: 18 pages, 10 figures, submitted to MNRAS, comments welcom
Saturation of Cs2 Photoassociation in an Optical Dipole Trap
We present studies of strong coupling in single-photon photoassociation of
cesium dimers using an optical dipole trap. A thermodynamic model of the trap
depletion dynamics is employed to extract absolute rate coefficents. From the
dependence of the rate coefficient on the photoassociation laser intensity, we
observe saturation of the photoassociation scattering probability at the
unitarity limit in quantitative agreement with the theoretical model by Bohn
and Julienne [Phys. Rev. A, 60, 414 (1999)]. Also the corresponding power
broadening of the resonance width is measured. We could not observe an
intensity dependent light shift in contrast to findings for lithium and
rubidium, which is attributed to the absence of a p or d-wave shape resonance
in cesium
Eber und Börge im Vergleich – Auswirkungen der Kastration auf agonistisches und sexuell motiviertes Verhalten unter ökologischen Haltungsbedingungen
Nach dem Verbot der betäubungslosen Ferkelkastration nach VO (EG) 889 (2008) zum 01.01.2012 stellt die Ebermast eine mögliche Alternative für die ökologische Schweinefleischerzeugung dar. Im Rahmen des Projektes „Ebermast im Verbund: Entwicklung eines Konzepts für die Produktion, Schlachtung, Verarbeitung und Vermarktung ökologisch erzeugter Eber entlang der Wertschöpfungskette“ ist es ein Ziel, das Ausmaß möglichen unerwünschten Verhaltens, wie agonistische Interaktionen und Aufreitverhalten der Eber, mit dem von Börgen unter praxisüblichen ökologischen Haltungsbedingungen zu vergleichen und wichtige Einflussfaktoren hierauf zu identifizieren. Auch mögliche Verletzungsfolgen sollen einbezogen werden. Aus einer Zwischenauswertung werden hier erste Ergebnisse zum Ausmaß des genannten Verhaltens und der Verletzungsfolgen vorgestellt. 9 Gruppen Eber und 7 Gruppen Börge wurden mit einem Lebendgewicht von etwa 80 kg auf vier ökologischen Praxisbetrieben beobachtet. Agonistische Interaktionen (Kopfschlagen, Beißen, Kampf und Besteigen ohne sexuelle Motivation) und Besteigen mit sexueller Motivation wurden mittels kontinuierlicher Verhaltenszählung (continuous behaviour sampling) jeweils über die ersten 15 Minuten einer jeden Lichtstunde von zusammenhängenden 48h-Aufnahmen ausgewertet. Zum selben Zeitpunkt wurden zusätzlich die Verletzungen bei den 109 Ebern und 91 Börgen gezählt. Eber zeigten bezüglich aller erhobener Verhaltensparameter gegenüber den Börgen signifikant höhere Häufigkeiten bzw. Dauern. Dagegen konnten hinsichtlich der Verletzungsscores zwischen Ebern und Börgen keine signifikanten Unterschiede festgestellt werden. Die Untersuchung wird fortgesetzt
Prevalence of Exocrine Pancreatic Insufficiency in Women with Obesity Syndrome: Assessment by Pancreatic Fecal Elastase 1
Background. Previous research on the combined association of 25-hydroxyvitamin D [25(OH)D] and exocrine pancreas insufficiency may have been limited by restricted age variability and a lack of representation of both body weight and body mass index. There are still too few conclusive reports about conspicuous vitamin D metabolism according to pancreatic fecal elastase 1 (FE1) in obese patients. Methods. Between May 2004 and July 2008, we investigated in 125 female patients with obesity syndrome at an average age of approximately 52.9 years as well as in age-matched 80 healthy female controls the prevalence of pancreas insufficiency. Serum levels of PTH, total calcium, and D3 vitamins calcitriol and calcifediol, as well as the concentration of fecal elastase 1 (FE1) were determined in patients and controls. Results. In 75 female nondiabetic patients with obesity syndrome (BMI 35 ≤ 40 kg/m2), calcifediol was markedly decreased (25.0 ± 4.9 ng/mL) compared to controls (50.2 ± 14.7 nmol/L; P < 0.01). FE1 level was significantly decreased in obese subjects compared to controls ( P < 0.01). Calcifediol was significantly lower in patients with morbid obesity (for calcifediol, P < 0.05). Conclusion. In obese females, pancreatic FE1 in feces confirms the extent of vitamin D supply, and thus shows a vitamin D3 deficiency, depending on the loss of stool content. There seems to be a connection between the loss of exocrine function and the increasing body mass index. Pancreas insufficiency, as detected by low FE1 concentrations, is frequent in obese patients. However, the BMI is an additional factor for lowered fecal excretion of FE1
Chloramidine/Bisindolylmaleimide-I-Mediated Inhibition of Exosome and Microvesicle Release and Enhanced Efficacy of Cancer Chemotherapy
Microvesicle (MV) release from tumour cells influences drug retention, contributing to cancer drug resistance. Strategically regulating MV release may increase drug retention within cancer cells and allow for lower doses of chemotherapeutic drugs. The contribution of exosomes to drug retention still remains unknown. Potential exosome and MV (EMV) biogenesis inhibitors, tested on human prostate cancer (PC3) cells for their capacity to inhibit EMV release, were also tested on PC3 and MCF-7 (breast cancer) cells for improving chemotherapy. Agents inhibiting EMV release most significantly, whilst maintaining cell viability, were chloramidine (Cl-amidine; 50 µM) and bisindolylmaleimide-I (10 µM). Apoptosis mediated by the chemotherapy drug 5-fluorouracil (5-FU) was significantly enhanced in PC3 cells in the presence of both these EMV inhibitors, resulting in a 62% (Cl-amidine + 5-FU) and 59% (bisindolylmaleimide-I + 5-FU) decrease in numbers of viable PC3 cells compared to 5-FU alone after 24 h. For MCF-7 cells, there were similar increased reductions of viable cells compared to 5-FU treatment alone ranging from 67% (Cl-amidine + 5-FU) to 58% (bisindolylmaleimide-I + 5-FU). Using combinatory treatment, the two EMV inhibitors further reduced the number of viable cancer cells tested. Neither inhibitor affected cell viability. Combining selected EMV inhibitors may pose as a novel strategy to enhance the efficacy of chemotherapeutic drug-mediated apoptosis
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