5,996 research outputs found
Extended search for point sources of neutrinos below and above the horizon: Covering energies from TeV to EeV with IceCube
Point source searches with neutrino telescopes like IceCube are normally
restricted to one hemisphere, due to the selection of up-going events as a way
of rejecting the atmospheric muon background. In this work we show that the
down-going region above the horizon can be included in the search by
suppressing the background through energy-sensitive selection procedures. This
approach increases the reach to the EeV regime of the signal spectrum, which
was previously not accessible due to the absorption of neutrinos with energies
above a PeV inside the Earth. We present preliminary results of this analysis,
which for the first time includes up-going as well as down-going muon events in
a combined approach. We used data collected with IceCube in a configuration of
22 strings. No significant excess above the atmospheric background is observed.
While other analyses provided results for the Northern hemisphere, this new
approach extends the field of view to a large part of the Southern sky, which
was previously not covered with IceCube.Comment: 4 pages, 1 figure. To be published in the proceedings of the 2nd
Heidelberg workshop "High-Energy Gamma-rays and Neutrinos from Extra-Galactic
Sources", 2009 (Journal of Modern Physics D
Digital signal processing for segmented HPGe detectors preprocessingalgorithms and pulse shape analysis
MINIBALL is an versatile spectrometer consisting of 24 longitudinally six-fold segmented HPGe detectors, build for the efficient detection of rare γ decays in nuclear reactions of radioactive ion beams. MINIBALL was the first spectrometer equipped with digital electronics. Pulse shape analysis algorithms to determine the interaction position of γ -rays were implemented on a Digital Signal Processor and validated in an experiment using a collimated γ -ray source. Emphasis was placed on the properties of the different digital signal processing algorithms, the consequences for the implementation and the applicability for position determination. The next generation of γ -ray spectrometers will consist of highly segmented HPGe detectors equipped with digital electronics, resulting in a more than ten-fold increase in complexity compared to current spectrometers. To enable the construction of a γ -ray tracking spectrometer, new and powerful digital electronics will be developed. Preprocessing algorithms, giving the γ -ray energy and generating event triggers, were implemented on a VME module equipped with fast A/D converters and tested with different detectors and sources. Emphasis was placed on the detailed simulation and understanding of the algorithms as well as the influence of electronics and detector onto the energy resolution
Parental investment and child health in a Yanomamö village suffering short-term food stress
The 1998 El Niño significantly reduced garden productivity in the
Upper Orinoco region in Venezuela. Consequently, parents were forced to
allocate food carefully to their children. Nutrition data collected from village
children combined with genealogical data allowed the determination of which
children suffered most, and whether the patterns of food distribution
accorded with predictions from parental investment theory. For boys, three
social variables accounted for over 70% of the variance in subcutaneous fat
after controlling for age: number of siblings, age of the mother’s youngest
child, and whether the mother was the senior or junior co-wife, or was
married monogamously. These results accord well with parental investment
theory. Parents experiencing food stress faced a trade-off between quantity
and quality, and between investing in younger versus older offspring. In
addition, boys with access to more paternal investment (i.e. no stepmother)
were better nourished. These variables did not account for any of the
variance in female nutrition. Girls’ nutrition was associated with the size of
their patrilineage and the number of non-relatives in the village, suggesting
that lineage politics may have played a role. An apparent lack of relationship
between orphan status and nutrition is also interesting, given that orphans
suffered high rates of skin flea infections. The large number of orphans being
cared for by only two grandparents suggests that grooming time may have
been the resource in short supply.
Introductio
Quantitative evaluation of multiband photographic techniques Final report
Quantitative evaluation of multiband photographic techniques using combination of black and white and color photo
Epigenetic Buffering in Introduced House Sparrows
Epigenetic buffering, as an environmentally induced increase in variance of epigenetic states that increases phenotypic variation to buffer populations against decreased fitness, may be a factor that resolves the genetic paradox of introduced species. DNA methylation is a molecular mechanism that could facilitate epigenetic buffering by changing in response to environmental stress. Therefore, epigenetic buffering can be detected through increased variance in DNA methylation in novel or heterogeneous environments. Introduced house sparrows (Passer domesticus) have well-documented phenotypic changes with low genetic diversity, high epigenetic diversity, and high variance in DNA methylation that provide a characteristic signature of epigenetic buffering. Here, we screened DNA methylation among introduced and native house sparrows from multiple widely separated geographic locations to test for evidence of epigenetic buffering. We used epiRADseq to detect differentially methylated regions and estimate total DNA methylation. We found that introduction history explained the patterns of DNA methylation among introduced and native house sparrows in a manner that supports epigenetic buffering. Recently introduced house sparrows had the highest variance in DNA methylation, and the most significantly different methylated sites. Established introduced house sparrows also had higher variance than native house sparrows. House sparrows from British Columbia and Brazil were more similar to recently introduced sparrows in methylation patterns, while the older established introduced sparrows, South Africa and Florida USA, were more similar to native house sparrows. We show that variance in DNA methylation is highest in the novel environments for the house sparrow. As environmental novelty encompasses intense stress and potentially heterogeneous environments, we suggest that epigenetic buffering is likely an important phenomenon for response to such conditions
ADEPT - Next Generation Process Management Technology
In the ADEPT project we have been working on the design and implementation of a next generation process management technology for several years. Based on a conceptual framework for dynamic process changes, on innovative process support functions, and on advanced implementation concepts, the developed system enables the realization of adaptive, process-aware information systems (PAIS). Basically, process changes can take place at the process type as well as the process instance level: Changes of single process instances may have to be carried out in an ad-hoc manner (e.g., to deal with an exceptional situation) and must not affect system robustness and consistency. Process type changes, in turn, must be quickly accomplished in order to adapt the PAIS to business process changes. This may also include the migration of (thousands of) instances to the new process schema (if desired). Important requirements are to perform respective migrations on-the-fly, to preserve correctness, and to avoid performance penalties
ADEPT2 - Next Generation Process Management Technology
If current process management systems shall be applied to a broad spectrum of applications, they will have to be significantly improved with respect to their technological capabilities. In particular, in dynamic environments it must be possible to quickly implement and deploy new processes, to enable ad-hoc modifications of single process instances at runtime (e.g., to add, delete or shift process steps), and to support process schema evolution with instance migration, i.e., to propagate process schema changes to already running instances. These requirements must be met without affecting process consistency and by preserving the robustness of the process management system. In this paper we describe how these challenges have been addressed and solved in the ADEPT2 Process Management System. Our overall vision is to provide a next generation process management technology which can be used in a variety of application domains
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