686 research outputs found
{YAGO}2: A Spatially and Temporally Enhanced Knowledge Base from {Wikipedia}
We present YAGO2, an extension of the YAGO knowledge base, in which entities, facts, and events are anchored in both time and space. YAGO2 is built automatically from Wikipedia, GeoNames, and WordNet. It contains 80 million facts about 9.8 million entities. Human evaluation confirmed an accuracy of 95\% of the facts in YAGO2. In this paper, we present the extraction methodology, the integration of the spatio-temporal dimension, and our knowledge representation SPOTL, an extension of the original SPO-triple model to time and space
Overlapping of Ranges of Eastern and Western Hognose Snakes in Southeastern Iowa
Overlapping of ranges of the eastern hognose snake (Heterodon platyrhinos Latreille) and the western hognose snake (Heterodon nasicus nasicus Baird and Girrard) is reported from a sand prairie in Muscatine County, Iowa
Alterations in gene expression and sensitivity to genotoxic stress following HdmX or Hdm2 knockdown in human tumor cells harboring wild-type p53
While half of all human
tumors possess p53 mutations, inactivation of wild-type p53 can also occur
through a variety of mechanisms that do not involve p53 gene mutation or
deletion. Our laboratory has been interested in tumor cells possessing
wild-type p53 protein and elevated levels of HdmX and/or Hdm2, two critical
negative regulators of p53 function. In this study we utilized RNAi to
knockdown HdmX or Hdm2 in MCF7 human breast cancer cells, which harbor
wild-type p53 and elevated levels of HdmX and Hdm2 then examined gene
expression changes and effects on cell growth. Cell cycle and growth assays
confirmed that the loss of either HdmX or Hdm2 led to a significant growth
inhibition and G1 cell cycle arrest. Although the removal of overexpressed
HdmX/2 appears limited to an anti-proliferative effect in MCF7 cells, the
loss of HdmX and/or Hdm2 enhanced cytotoxicity in these same cells exposed
to DNA damage. Through the use of Affymetrix GeneChips and subsequent
RT-qPCR validations, we uncovered a subset of anti-proliferative p53 target
genes activated upon HdmX/2 knockdown. Interestingly, a second set of
genes, normally transactivated by E2F1 as cells transverse the G1-S phase
boundary, were found repressed in a p21-dependent manner following HdmX/2
knockdown. Taken together, these results provide novel insights into the
reactivation of p53 in cells overexpressing HdmX and Hdm2
Gene Expression Profiles from Needle Biopsies Provide Useful Signatures of Non-Small Cell Lung Carcinomas
Gene expression profiles from DNA microarrays can provide molecular signatures that improve tumor classification, prognosis, and treatment options. While much of this work has focused on isolation of RNA from the resected tumor, fewer studies have utilized RNA from fine needle aspirates (FNA). In this pilot study we examined whether the gene signatures obtained from FNA samples would correlate with signatures taken from the resected tumor. Based on NSCLC gene expression profiles obtained from eleven sets of FNA and tumor samples we obtained a high concordance of FNA profiles matching their matched tumor sample. These results suggest that FNA samples may provide informative gene expression signatures regarding the potential aggressiveness of non-small-cell lung carcinomas
Improved Implementation of Point Location in General Two-Dimensional Subdivisions
We present a major revamp of the point-location data structure for general
two-dimensional subdivisions via randomized incremental construction,
implemented in CGAL, the Computational Geometry Algorithms Library. We can now
guarantee that the constructed directed acyclic graph G is of linear size and
provides logarithmic query time. Via the construction of the Voronoi diagram
for a given point set S of size n, this also enables nearest-neighbor queries
in guaranteed O(log n) time. Another major innovation is the support of general
unbounded subdivisions as well as subdivisions of two-dimensional parametric
surfaces such as spheres, tori, cylinders. The implementation is exact,
complete, and general, i.e., it can also handle non-linear subdivisions. Like
the previous version, the data structure supports modifications of the
subdivision, such as insertions and deletions of edges, after the initial
preprocessing. A major challenge is to retain the expected O(n log n)
preprocessing time while providing the above (deterministic) space and
query-time guarantees. We describe an efficient preprocessing algorithm, which
explicitly verifies the length L of the longest query path in O(n log n) time.
However, instead of using L, our implementation is based on the depth D of G.
Although we prove that the worst case ratio of D and L is Theta(n/log n), we
conjecture, based on our experimental results, that this solution achieves
expected O(n log n) preprocessing time.Comment: 21 page
High aldosterone, hypertension and adrenal adenoma in a 36-year-old pregnant patient: Is this primary aldosteronism?
A 36-year-old woman presented at 16 weeks’ gestation with severe hypertension. In comparison to the non-pregnant reference normal ranges, potassium was 3.1-3.9 mmol/L, aldosterone 2570-3000 pmol/L (N 250-2885) renin was unsuppressed (24-76.4 ng/L (N1.7–23.9)), with aldosterone to renin ratios in the reference range. An adrenal MRI scan demonstrated a 1.8 × 1.4 cm left adrenal adenoma. Primary aldosteronism was strongly suspected and surgery considered. However, she was managed conservatively with labetalol and modified-release nifedipine with no obstetric complications. Post-partum blood pressures remained elevated with normal aldosterone (539 pmol/L), unsuppressed renin (5.2 ng/L) and normal aldosterone-to-renin ratio (104 (N \u3c 144)). Suspected primary hyperaldosteronism is challenging to investigate and manage in pregnancy. The accepted screening and confirmatory tests are either contraindicated or not validated in pregnancy. Pregnancy has significant effects on the renin-angiotensin-aldosterone pathway leading to physiologic elevations in both aldosterone and renin. While primary hyperaldosteronism has been associated with poor pregnancy outcomes, optimal management in pregnancy is not clearly established
Well-balanced treatment of gravity in astrophysical fluid dynamics simulations at low Mach numbers
Accurate simulations of flows in stellar interiors are crucial to improving
our understanding of stellar structure and evolution. Because the typically
slow flows are merely tiny perturbations on top of a close balance between
gravity and the pressure gradient, such simulations place heavy demands on
numerical hydrodynamics schemes. We demonstrate how discretization errors on
grids of reasonable size can lead to spurious flows orders of magnitude faster
than the physical flow. Well-balanced numerical schemes can deal with this
problem. Three such schemes were applied in the implicit, finite-volume
Seven-League Hydro (SLH) code in combination with a low-Mach-number numerical
flux function. We compare how the schemes perform in four numerical experiments
addressing some of the challenges imposed by typical problems in stellar
hydrodynamics. We find that the - and deviation well-balancing
methods can accurately maintain hydrostatic solutions provided that
gravitational potential energy is included in the total energy balance. They
accurately conserve minuscule entropy fluctuations advected in an isentropic
stratification, which enables the methods to reproduce the expected scaling of
convective flow speed with the heating rate. The deviation method also
substantially increases accuracy of maintaining stationary orbital motions in a
Keplerian disk on long timescales. The Cargo-LeRoux method fares substantially
worse in our tests, although its simplicity may still offer some merits in
certain situations. Overall, we find the well-balanced treatment of gravity in
combination with low Mach number flux functions essential to reproducing
correct physical solutions to challenging stellar slow-flow problems on
affordable collocated grids.Comment: Accepted for publication in A&
Recommended from our members
Detection probabilities for sessile organisms
Estimation of population sizes and species ranges are central to population and conservation biology. It is widely appreciated that imperfect detection of mobile animals must be accounted for when estimating population size from presence-absence data. Sessile organisms also are imperfectly detected, but correction for detection probability in estimating their population sizes is rare. We illustrate challenges of detection probability and population estimation of sessile organisms using censuses of red wood ant (Formica rufa-group) nests as a case study. These ants, widespread in the northern hemisphere, can make large (up to 2-m tall), highly visible nests. Using data from a mapping campaign by eight observers with varying experience of sixteen 3600-m2 plots in the Black Forest region of southwest Germany, we compared three different statistical approaches (a nest-level data-augmentation patch-occupancy model with event-specific covariates; a plot-level Bayesian and maximum likelihood model; non-parametric Chao-type estimators) for quantifying detection probability of sessile organisms. Detection probabilities by individual observers of red wood ant nests ranged from 0.31 – 0.64 for small nests, depending on observer experience and nest size (detection rates were approximately 0.17 higher for large nests), but not on habitat characteristics (forest type, local vegetation). Robust estimation of population density of sessile organisms – even highly apparent ones such as red wood ant nests – thus requires estimation of detection probability, just as it does when estimating population density of rare or cryptic species. Our models additionally provide approaches to calculate the number of observers needed for a required level of accuracy. Estimating detection probability is vital not only when censuses are conducted by experts, but also when citizenscientists are engaged in mapping and monitoring of both common and rare species.Organismic and Evolutionary Biolog
Motilitätsstörungen des Ösophagus
Zusammenfassung: Motilitätsstörungen des Ösophagus umfassen ein heterogenes Spektrum von Erkrankungen. Primäre Fehlbildungen des Ösophagus sind heute zwar einer verbesserten chirurgischen und gastroenterologischen Therapie zugänglich, führen jedoch zu langfristig persistierender ösophagealer Dysmotilität. Die Achalasie resultiert aus einer gestörten Relaxation des gastroösophagealen Sphinkters. Systemische Erkrankungen können mit einer sekundären ösophagealen Motilitätsstörung einhergehen. Zahlreiche neuromuskuläre Erkrankungen mit viszeraler Manifestation zeigen eine ösophageale Beteiligung. Selten kann eine Aganglionose bis in den Ösophagus reichen. Die wachsende Gruppe der Myopathien schließt metabolische und mitochondriale Störungen ein, deren zunehmende Charakterisierung genetischer Defekte vereinzelt bereits therapeutische Ansätze eröffnet. Infektbedingte Ösophagitiden zeigen besonders bei immunkompromittierten Patienten eine schwere Störung der Motilität. Immunologisch vermittelte Entzündungsprozesse im und um den Ösophagus werden allmählich besser verstanden. Schließlich können seltene Tumoren und tumorartige Läsionen eine Dysmotilität des Ösophagus verursache
Theory for the coupling between longitudinal phonons and intrinsic Josephson oscillations in layered superconductors
In this publication a microscopic theory for the coupling of intrinsic
Josephson oscillations in layered superconductors with longitudinal
c-axis-phonons is developed. It is shown that the influence of lattice
vibrations on the c-axis transport can be fully described by introducing an
effective longitudinal dielectric function. Resonances in the
I-V-characteristic appear at van Hove singularities of both acoustical and
optical longitudinal phonon branches. This provides a natural explanation of
the recently discovered subgap structures in the I-V-characteristic of highly
anisotropic cuprate superconductors. The effect of the phonon dispersion on the
damping of these resonances and the coupling of Josephson oscillations in
different resistive junctions due to phonons are discussed in detail.Comment: submitted to Phys. Rev. B, corrections following referee repor
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