460 research outputs found
PARSEC: A Parametrized Simulation Engine for Ultra-High Energy Cosmic Ray Protons
We present a new simulation engine for fast generation of ultra-high energy
cosmic ray data based on parametrizations of common assumptions of UHECR origin
and propagation. Implemented are deflections in unstructured turbulent
extragalactic fields, energy losses for protons due to photo-pion production
and electron-pair production, as well as effects from the expansion of the
universe. Additionally, a simple model to estimate propagation effects from
iron nuclei is included. Deflections in galactic magnetic fields are included
using a matrix approach with precalculated lenses generated from backtracked
cosmic rays. The PARSEC program is based on object oriented programming
paradigms enabling users to extend the implemented models and is steerable with
a graphical user interface.Comment: 10 pages, 6 figures, accepted for publication in Astroparticle
Physic
Der Einfluà von körperlicher Leistung auf das Immunsystem bei Patienten mit variablem Immundefekt (CVID)
Mit unserer Studie sollte der EinfluĂ von körperlicher Belastung auf Lymphozytenpopulationen bei Patienten mit variablem Immundefektsysndrom CVID untersucht werden. Um eine Verbindung zu alltĂ€glichen Situationen zu schaffen, wĂ€hlten wir eine moderate Belastung, in Form einer Laufstrecke von 3.5 km. Es wurden vielfach signifikante Unterschiede der Zellverteilung zwischen der Patienten- und Kontrollgruppe deutlich bei der CD8 T-Zellpopulation, bei den CD4 Helferzellen sowie bei den CD45RO - und CD95 - positiven CD4 Helferzellen und bei den NatĂŒrlichen Killerzellen. Wir konnten sehen, daĂ bei den Patienten in der CD8 T-Zellpopulation bereits vor der Belastung eine höhere Zellzahl vorlag als bei den Kontrollpersonen. Die körperliche Belastung hatte bei dieser Zellgruppe dann zur Folge, daĂ direkt im AnschluĂ, durch einen Zellzahlanstieg bei den Patienten, ein signifikanter Unterschied der Zellzahl vorlag. Bei den T4-Helferzellen war bereits zum Ausgangszeitpunkt eine signifikant erniedrigte CD4-Zellzahl bei der Patientengruppe zu erkennen (p = 0.02; Median 616 Zellen/”l; Range 450 - 677 Zellen/”l ). Unter Belastung kam es hierbei zu einem signifikanten Zellzahlanstieg (p 0.05). Bei der nĂ€heren Betrachtung der CD4-Untergruppen ergab sich, daĂ sich die Zellzahlerhöhung in erster Linie in der Population der CD45RO positiven Memory-Zellen abspielte. Desweiteren war ein Anstieg in der Gruppe der CD95 exprimierenden CD4-Zellen zu sehen. In der Kontrollgruppe war hierbei, wie zu erwarten, keine auffĂ€llige Entwicklung in der Zellzahl zu erheben. Bei den NatĂŒrlichen Killerzellen, die, wie in der Literatur beschrieben, sehr sensibel auf körperliche Belastung reagieren, zeigte sich ein Ă€hnlicher Verlauf in den beiden Gruppen. Erst zu den MeĂpunkten 90 Minuten und 120 Minuten nach Belastung war dann bei den Patienten eine grenzwertig (p=0.053) signifikante Zellzahlerniedrigung auffĂ€llig. Inwieweit diese Abweichungen nun als pathologische Erscheinungen bzw. als Kompensationsmechanismen zu werten sind, ist anhand der bislang vorliegenden Daten schwer zu beurteilen. WeiterfĂŒhrende Studien sollten zusĂ€tzlich Bezug auf die ZellaktivitĂ€t, bzw. die ZytotoxizitĂ€t nehmen. Andererseits wĂ€re eine Langzeitbetrachtung der Patienten unter körperlicher Leistung wĂŒnschenswert, um Entwicklungen erkennen und eventuell nĂŒtzen zu können, im Sinne eines gezielten "immununterstĂŒtzenden" Trainings
Unzerschnittene FreirÀume als Schutzgut? Landschaftszerschneidung in Deutschland mit besonderem Fokus auf Sachsen
Dieser Beitrag widmet sich der Entwicklung der Thematik Landschaftszerschneidung in
Deutschland, dem gegenwÀrtigen Stand der Auswertungen und der Integration in Monitoring
und Planung. Eingegangen wird auch auf die unterschiedlichen Indikatoren, die
sich zur Messung des Zerschneidungsgrades etabliert haben. Nach einem Ăberblick
ĂŒber die aktuell vorliegenden bundes- und landesweiten Untersuchungen zur Landschaftszerschneidung
werden am Beispiel von Sachsen Untersuchungsergebnisse zur
Entwicklung der Landschaftszerschneidung von 1930 bis heute sowie eine Prognose fĂŒr
2020 dargestellt. FĂŒr Sachsen und die angrenzenden BundeslĂ€nder wurde untersucht, ob
und wie das Schutzgut âUnzerschnittene FreirĂ€umeâ in PlĂ€ne der Regional- und Landesplanung
aufgenommen wurde. Ăberblicksartig werden der aktuelle Stand der Diskussion
zur Einbindung der Landschaftszerschneidung in Planinstrumente gegeben und
aktuelle Entwicklungen aufgezeigt.This paper concerns the development of interest in the topic of the fragmentation of the
German countryside; it considers the current state of analysis and integration of the
issue in both monitoring and planning. It also includes discussion of the various indicators
which have become established for measuring the degree of fragmentation. Following
a survey of recent studies into the fragmentation of the countryside, at both federal
and state levels, the paper focuses for illustration on the federal state of Saxony and
lays out the findings of studies tracing the development of landscape fragmentation
from 1930 to the present day, as well as offering a prognosis for 2020. For both Saxony
and its neighbouring states, the question at issue was whether, and in what ways, the
protected asset referred to as ânon-fragmented open spacesâ has been adopted within
plans at the levels of regional and state-level planning. The paper offers an overview of
the current state of discussion on the inclusion of the issue of landscape fragmentation
in planning instruments and points to developments currently in process
CRPropa 3.0 - a Public Framework for Propagating UHE Cosmic Rays through Galactic and Extragalactic Space
The interpretation of experimental data of ultra-high energy cosmic rays
(UHECRs) above 10^17 eV is still under controversial debate. The development
and improvement of numerical tools to propagate UHECRs in galactic and
extragalactic space is a crucial ingredient to interpret data and to draw
conclusions on astrophysical parameters. In this contribution the next major
release of the publicly available code CRPropa (3.0) is presented. It reflects
a complete redesign of the code structure to facilitate high performance
computing and comprises new physical features such as an interface for galactic
propagation using lensing techniques and inclusion of cosmological effects in a
three-dimensional environment. The performance is benchmarked and first
applications are presented.Comment: 4 pages, 3 figures. Proceedings of the 33rd International Cosmic Ray
Conference (ICRC), Rio de Janeiro, Brazil, 2-9 July 201
An IMERG-Based Optimal Extended Probabilistic Climatology (EPC) as a Benchmark Ensemble Forecast for Precipitation in the Tropics and Subtropics
Current numerical weather prediction models show limited skill in predicting low-latitude precipitation. To aid future improvements, be it with better dynamical or statistical models, we propose a well-defined benchmark forecast. We use the arguably best available high-resolution, gauge-calibrated, gridded precipitation product, the Integrated Multisatellite Retrievals for GPM (IMERG) âfinal runâ in a ±15-day window around the date of interest to build an empirical climatological ensemble forecast. This window size is an optimal compromise between statistical robustness and flexibility to represent seasonal changes. We refer to this benchmark as extended probabilistic climatology (EPC) and compute it on a 0.1° Ă 0.1° grid for 40°Sâ40°N and the period 2001â19. To reduce and standardize information, a mixed BernoulliâGamma distribution is fitted to the empirical EPC, which hardly affects predictive performance. The EPC is then compared to 1-day ensemble predictions from the European Centre for Medium-Range Weather Forecasts (ECMWF) using standard verification scores. With respect to rainfall amount, ECMWF performs only slightly better than EPS over most of the low latitudes and worse over high-mountain and dry oceanic areas as well as over tropical Africa, where the lack of skill is also evident in independent station data. For rainfall occurrence, EPC is superior over most oceanic, coastal, and mountain regions, although the better potential predictive ability of ECMWF indicates that this is mostly due to calibration problems. To encourage the use of the new benchmark, we provide the data, scripts, and an interactive web tool to the scientific community
Development and deployment of a precision underwater positioning system for in situ laser Raman spectroscopy in the deep ocean
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 52 (2005): 2376-2389, doi:10.1016/j.dsr.2005.09.002.The field of ocean geochemistry has recently been expanded to include in
situ laser Raman spectroscopic measurements in the deep ocean. While this
technique has proved to be successful for transparent targets, such as fluids and
gases, difficulty exists in using deep submergence vehicle manipulators to
position and control the very small laser spot with respect to opaque samples of
interest, such as many rocks, minerals, bacterial mats, and seafloor gas hydrates.
We have developed, tested, and successfully deployed by remotely operated
vehicle (ROV) a precision underwater positioner (PUP) which provides the
stability and precision movement required to perform spectroscopic
measurements using the Deep Ocean In Situ Spectrometer (DORISS) instrument
on opaque targets in the deep ocean for geochemical research. The positioner is
also adaptable to other sensors, such as electrodes, which require precise control
and positioning on the seafloor. PUP is capable of translating the DORISS
optical head with a precision of 0.1 mm in three dimensions over a range of at
least 15 cm, at depths up to 4000 m, and under the normal range of oceanic
conditions (T, P, current velocity). The positioner is controlled, and spectra are
obtained, in real time via Ethernet by scientists aboard the surface vessel. This
capability has allowed us to acquire high quality Raman spectra of targets such
as rocks, shells, and gas hydrates on the seafloor, including the ability to scan
the laser spot across a rock surface in sub-millimeter increments to identify the
constituent mineral grains. These developments have greatly enhanced the
ability to obtain in situ Raman spectra on the seafloor from an enormous range
of specimens.Funding was provided by a grant to MBARI from the David and Lucile Packard
Foundation
Role of CâXâC chemokines as regulators of angiogenesis in lung cancer
Lung cancer is the leading cause of malignancyârelated mortality in the U.S. and is predicted to increase over the remainder of this decade. Despite attempts to advance early diagnosis and use combination therapies, the clinical response of this cancer yields an overall 5âyear survival rate of less than 15%. Clearly, new strategies for therapy are indicated. Although carcinogenesis is complex, tumor growth beyond 1â2 mm3 is dependent on angiogenesis. One of the potential mechanisms that allows for tumorigenesis is dysregulation of the balance of angiogenic and angiostatic factors that favors net neovascularization within the primary tumor. Numerous studies have investigated the role of a variety of molecules in the regulation of angiogenesis. Recently, interleukinâ8 (ILâ8), a member of the CâXâC chemokine family, has been found to be an angiogenic factor. In contrast, platelet factor 4 (PF4), another CâXâC chemokine, has been shown to have angiostatic properties. It is interesting that the major structural difference between ILâ8 and PF4 is the presence of the NH2âterminal ELR (GluâLeuâArg) motif that precedes the first cysteine amino acid residue of ILâ8 and is important in ligand/receptor interactions. We hypothesize that angiogenesis associated with tumorigenesis is dependent on members of the CâXâC chemokine family acting as either angiogenic or angiostatic factors. This paradigm predicts that the biological balance in the expression of these CâXâC chemokines dictates whether the neoplasm grows and develops metastatic potential or regresses. In this review we discuss our recent laboratory findings that support this contention and suggest that further elucidation of the biology of CâXâC chemokines in the context of neovascularization of nonsmall cell lung cancer will permit novel targeted therapy aimed specifically at attenuating tumor growth and metastasis. J. Leukoc. Biol. 57: 752â762; 1995.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141888/1/jlb0752.pd
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