2,152 research outputs found
Developing numerical libraries in Java
The rapid and widespread adoption of Java has created a demand for reliable
and reusable mathematical software components to support the growing number of
compute-intensive applications now under development, particularly in science
and engineering. In this paper we address practical issues of the Java language
and environment which have an effect on numerical library design and
development. Benchmarks which illustrate the current levels of performance of
key numerical kernels on a variety of Java platforms are presented. Finally, a
strategy for the development of a fundamental numerical toolkit for Java is
proposed and its current status is described.Comment: 11 pages. Revised version of paper presented to the 1998 ACM
Conference on Java for High Performance Network Computing. To appear in
Concurrency: Practice and Experienc
Acute complete heart block in dogs
A study has been conducted immediately and up to 18 days after the surgical production of complete heart block in dogs. Immediately after surgery cardiac output, coronary flow, and mean arterial pressure were reduced in rough proportion to the degree of bradycardia. In time, these measures began to return toward preoperative levels. Paralleling the diminished left ventricular work was a diminished left ventricular oxygen consumption with little consequent change in myocardial efficiency. Small rises were detected in central venous pressure. At autopsy, the only unequivocal abnormality was myocardial hypertrophy which became measurable between 2 and 18 days after operation
Spatial patterns of African ungulate aggregation reveal complex but limited risk effects from reintroduced carnivores
Striatal dopamine D2 receptor binding of risperidone in schizophrenic patients as assessed by 123I-iodobenzamide SPECT: a comparative study with olanzapine
The aim of this investigation was to compare the degree of striatal dopamine-(D2) receptor blockade by two atypical antipsychotic drugs, risperidone and olanzapine. The percentage of D2 receptor occupancy during treatment was calculated by comparing the results of 123I-iodobenzamide SPECT with those from healthy control subjects. Twenty inpatients suffering from schizophrenia or schizoaffective psychosis according to DSM IV/ICD-10 criteria were treated with clinically recommended doses of risperidone and compared with 13 inpatients treated with up to 20 mg olanzapine. Neuroleptic dose and D2 receptor blockade correlated strongly for both risperidone (Pearson r = –0.86, p = 0.0001) and olanzapine (Pearson r = –0.77, p = 0.002). There was no significant difference between the D2 receptor occupancy of the two substances when given in the clinically recommended dose range (unpaired t-test, t= –0.112, p=0.911)
Spatial variation in leopard (Panthera pardus) site use across a gradient of anthropogenic pressure in Tanzania's Ruaha landscape
Understanding large carnivore occurrence patterns in anthropogenic landscapes adjacent to protected areas is central to developing actions for species conservation in an increasingly human-dominated world. Among large carnivores, leopards (Panthera pardus) are the most widely distributed felid. Leopards occupying anthropogenic landscapes frequently come into conflict with humans, which often results in leopard mortality. Leopards’ use of anthropogenic landscapes, and their frequent involvement with conflict, make them an insightful species for understanding the determinants of carnivore occurrence across human-dominated habitats. We evaluated the spatial variation in leopard site use across a multiple-use landscape in Tanzania’s Ruaha landscape. Our study region encompassed i) Ruaha National Park, where human activities were restricted and sport hunting was prohibited; ii) the Pawaga-Idodi Wildlife Management Area, where wildlife sport hunting, wildlife poaching, and illegal pastoralism all occurred at relatively low levels; and iii) surrounding village lands where carnivores and other wildlife were frequently exposed to human-carnivore conflict related-killings and agricultural habitat conversion and development. We investigated leopard occurrence across the study region via an extensive camera trapping network. We estimated site use as a function of environmental (i.e. habitat and anthropogenic) variables using occupancy models within a Bayesian framework. We observed a steady decline in leopard site use with downgrading protected area status from the national park to the Wildlife Management Area and village lands. Our findings suggest that human-related activities such as increased livestock presence and proximity to human households exerted stronger influence than prey availability on leopard site use, and were the major limiting factors of leopard distribution across the gradient of human pressure, especially in the village lands outside Ruaha National Park. Overall, our study provides valuable information about the determinants of spatial distribution of leopards in human-dominated landscapes that can help inform conservation strategies in the borderlands adjacent to protected areas
The Messy Nature of Fiber Spectra: Star-Quasar Pairs Masquerading as Dual Type 1 AGNs
Theoretical studies predict that the most significant growth of supermassive
black holes occurs in late-stage mergers, coinciding with the manifestation of
dual active galactic nuclei (AGNs), and both major and minor mergers are
expected to be important for dual AGN growth. In fact, dual AGNs in minor
mergers should be signposts for efficient minor merger-induced SMBH growth for
both the more and less massive progenitor. We identified two candidate dual
AGNs residing in apparent minor mergers with mass ratios of 1:7 and
1:30. SDSS fiber spectra show broad and narrow emission lines in the
primary nuclei of each merger while only a narrow [O III] emission line and a
broad and prominent H/[N II] complex is observed in the secondary
nuclei. The FWHMs of the broad H lines in the primary and secondary
nuclei are inconsistent in each merger, suggesting that each nucleus in each
merger hosts a Type 1 AGN. However, spatially-resolved LBT optical spectroscopy
reveal rest-frame stellar absorption features, indicating the secondary sources
are foreground stars and that the previously detected broad lines are likely
the result of fiber spillover effects induced by the atmospheric seeing at the
time of the SDSS observations. This study demonstrates for the first time that
optical spectroscopic searches for Type 1/Type 1 pairs similarly suffer from
fiber spillover effects as has been observed previously for Seyfert 2 dual AGN
candidates. The presence of foreground stars may not have been clear if an
instrument with more limited wavelength range or limited sensitivity had been
used.Comment: 15 pages including appendix and references, 6 figures, 1 table.
Accepted for publication in Ap
Neural field model for measuring and reproducing time intervals
The continuous real-time motor interaction with our environment requires the capacity to measure and produce time intervals in a highly flexible manner. Recent neurophysiological evidence suggests that the neural computational principles supporting this capacity may be understood from a dynamical systems perspective: Inputs and initial conditions determine how a recurrent neural network evolves from a “resting state” to a state triggering the action. Here we test this hypothesis in a time measurement and time reproduction experiment using a model of a robust neural integrator based on the theoretical framework of dynamic neural fields. During measurement, the temporal accumulation of input leads to the evolution of a self-stabilized bump whose amplitude reflects elapsed time. During production, the stored information is used to reproduce on a trial-by-trial basis the time interval either by adjusting input strength or initial condition of the integrator. We discuss the impact of the results on our goal to endow autonomous robots with a human-like temporal cognition capacity for natural human-robot interactions.The work received financial support from FCT through the PhD fellowship
PD/BD/128183/2016, the project ”Neurofield” (POCI-01-0145-FEDER-031393)
and the research centre CMAT within the project UID/MAT/00013/2013
Updated full range of Eliciting Dose values for Cow’s milk for use in food allergen risk assessment
Access to Eliciting Doses (ED) for allergens enables advanced food allergen risk assessment. Previously, the full ED range for 14 allergenic foods, including milk, and recommendations for their use were provided (Houben et al., 2020). Additional food challenge studies with cow’s milk-allergic patients added 247 data points to the original dataset. Using the Stacked Model Averaging statistical method for interval-censored data on the 697 individual NOAELs and LOAELs for milk generated an updated full ED distribution. The ED01 and ED05, the doses at which 1% and 5% of the milk-allergic population would be predicted to experience any objective allergic reaction, were 0.3 and 3.2 mg milk protein for the discrete and 0.4 mg and 4.3 mg milk protein for the cumulative dose distribution, respectively. These values are slightly higher but remain within the 95% confidence interval of previously published EDs. We recommend using the updated EDs for future characterization of risks of exposure of milk-allergic individuals to milk protein. This paper contributes to the discussion on the Reference Dose for milk in the recent Ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens. It will also benefit harmonization of food allergen risk assessment and risk management globally
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