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1.
Opt Express ; 21(2): 2263-78, 2013 Jan 28.
Article in English | MEDLINE | ID: mdl-23389206

ABSTRACT

We report on design, manufacture, and testing of a Slewing Mirror Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash Observatory-pathfinder (UFFO-p) for space-based prompt measurement of early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT can deliver the images of GRB optical counterparts to the intensified CCD detector within 1.5~1.8 s over ± 35 degrees in the slewing field of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides a 17 × 17 arcmin² instantaneous field of view. Technical details of design, construction, the laboratory performance tests in space environments for this unique SMT are described in conjunction with the plan for in-orbit operation onboard the Lomonosov satellite in 2013.


Subject(s)
Lenses , Radiometry/instrumentation , Spacecraft/instrumentation , Telescopes , Equipment Design , Equipment Failure Analysis , Gamma Rays , Photons , Ultraviolet Rays
2.
Proc Biol Sci ; 268(1470): 921-4, 2001 May 07.
Article in English | MEDLINE | ID: mdl-11370964

ABSTRACT

If individuals occupy habitats in a way that maximizes their fitness, if they are free to occupy the habitats they choose and if fitness declines with population density, then their abundance across habitats should follow an ideal free distribution. But, if individuals are genetically related, this simple fitness-maximization mechanism breaks down. Habitat occupation should obey Hamilton's rule (natural selection favours traits causing a loss in individual fitness as long as they result in an equal or greater gain in inclusive fitness) and depends more on inclusive fitness than it does on individual fitness. We demonstrate that the resulting inclusive-fitness distribution inflates the population density in habitats of poorer inherent quality, creating pronounced source sink dynamics. We also show that density-dependent habitat selection among relatives reinforces behaviours such as group defence and interspecific territoriality, and that it explains many anomalies in dispersal and foraging.


Subject(s)
Biological Evolution , Environment , Models, Biological , Animals , Models, Statistical , Mole Rats , Population Density , Selection, Genetic
3.
Trends Ecol Evol ; 15(11): 460-464, 2000 Nov 01.
Article in English | MEDLINE | ID: mdl-11050349

ABSTRACT

One of the most ubiquitous phenomena of all natural populations is their variability in numbers in space and time. However, there are notable differences among populations in the way the population size fluctuates. One of the major challenges in population and community ecology is to explain and understand this variety and to find possible underlying rules that might be modified from case-to-case. Population variability also has a spatial component because fluctuations are often synchronized over relatively large distances. Recently, this has led to growing interest in how 'internal' (density-dependent) processes interact with 'external' factors such as environmental variability.

4.
Am Nat ; 151(3): 256-63, 1998 Mar.
Article in English | MEDLINE | ID: mdl-18811356

ABSTRACT

We examine the effects of environmental noise on populations that are parts of simple two-species food webs. We assume that the species are strongly interacting and that one or the other population is affected by the noise signal. Further assuming that a stable equilibrium with positive population densities exists, we are able to perform a complete frequency analysis of the system. If only one of the populations is subject to noise, the relative noise response by both populations is fully determined by the sign of a single element of the Jacobian matrix. The analysis is readily extended to cases when both species are affected by noise or when the food web has more than two species. The general conclusion about relative responses to noise is then less unambiguous, but the power spectra describing the frequency composition of the population variabilities are nevertheless completely determined. These results are entirely independent on the exact nature of the interaction (i.e., predation, competition, mutualism) between the populations. The results show that the interpretation of the "color" of ecological time series (i.e., the frequency composition of population variability over time) may be complicated by species interactions. The propagation of noise signals through food webs and the importance of web structure for the expected response of all parts of the web to such signals is a challenging field for future studies.

6.
Educ Med Salud ; 14(4): 355-70, 1980.
Article in Spanish | MEDLINE | ID: mdl-7449703

ABSTRACT

The authors regard every hospital as a fertile field for scientific research, by which they do not, however, imply that it must be converted into a research center. They assert that both medical and biopsychosocial research and administrative research in hospitals should go forward in harmony with the medical care provided to the community and with medical education. For them research in hospitals is a necessary activity, which should therefore be endowed with personnel motivated to conduct it and with sufficient material resources and financing. The director of the hospital has a fundamental part to play in promoting scientific research in his establishment. They state that research work should be formally programmed on the basis of the circumstances of each institution and of priorities resting on objective criteria.


Subject(s)
Health Services Research , Hospital Administration , Brazil
7.
Educación Médica y Salud (OPS) ; 14(4): 355-70, 1980.
Article in Spanish | PAHO | ID: pah-5666

ABSTRACT

The authors regard every hospital as a fertile field for scientific research, by which they do not, however, imply that it must be converted into a research center. They assert that both medical and biopsychosocial research and administrative research in hospitals should go forward in harmony with the medical care provided to the community and with medical education. For them research in hospitals is a necessary activity, which should therefore be endowed with personnel motivated to conduct it and with sufficient material resources and financing. The director of the hospital has a fundamental part to play in promoting scientific research in his establishment. They state that research work should be formally programmed on the basis of the circumstances of each institution and of priorities resting on objective criteria (Au)


Subject(s)
Health Services Research , Hospital Administration , Brazil
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