3,178 research outputs found
AGE STRUCTURE OR FUNCTIONAL RESPONSE? RECONCILING THE ENERGETICS OF SURPLUS PRODUCTION BETWEEN SINGLE-SPECIES MODELS AND ECOSIM
Whole-ecosystem foodweb models, specifically the dynamic model ECOSIM, contain specific hypotheses for surplus production that differ from traditional single-species management models. Specifically, ECOSIM begins with an assumption that all species are tightly connected and energetic surplus does not arise through fishing, whereas single-species fishing theory implies that fishing leads to surplus by removing larger, older, less-productive fish from populations. Although ECOPATH production ratios and single-species estimated production levels are both derived from the dynamics of von Bertalanffy consumption and growth equations, the dynamics of ECOSIM differ from the implied bioenergetics of fishing as applied to age-structured populations. Specifically, while the ECOSIM “Arena” functional response and the von Bertalanffy equations both lead to the appearance of densitydependence in predator consumption per unit biomass, the difference in starting assumptions between the models leads ECOSIM to “fix production energetics” while age-structured models capture changes in within-population energetics between populations of younger versus older fish. This may cause ECOSIM to greatly overestimate the amount of biomass supportable in “pristine” systems of large, mature fish, especially when projections are based on models of currently exploited ecosystems. However, if the ECOSIM Arena is seen as a proxy for age structure rather than as a function of predator/prey behaviour, the original derivation of von Bertalanffy growth equations, applied as a modification of ECOSIM, may allow the predictions made by biomass dynamics ecosystem models to incorporate critical life-history characteristics of modelled populations. Afr. J. mar. Sci. 26: 289–30
Nearly Four Million California Adults Are Victims of Intimate Partner Violence
Based on 2007 California Health Interview Survey data, analyzes the incidence and nature of physical and/or sexual intimate partner violence by gender, race/ethnicity, nativity, marital status, and sexual orientation
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Cognitive and behavioral improvement in adults with fragile X syndrome treated with metformin-two cases.
BackgroundThe majority of individuals with fragile X syndrome (FXS) have intellectual disability, behavioral problems, autism, and language deficits. IQ typically declines with age in boys with the full mutation. The results of preclinical studies demonstrated that metformin, a biguanide used to treat type 2 diabetes, rescues multiple phenotypes of FXS in both Drosophila and mouse models. Preliminary studies of patients with FXS demonstrated improvements in behavior.MethodsHere, we present two cases of individuals who have been treated with metformin clinically for one year.ResultsBoth patients demonstrated significant cognitive and behavioral improvements. They also improved eating habits and normalization of their weight percentiles.ConclusionMetformin may be a candidate drug for treatment of several types of symptoms in individuals with FXS
Failure of the Standard Coupled-Channels Method in Describing the Inelastic Reaction Data: On the Use of a New Shape for the Coupling Potential
We present the failure of the standard coupled-channels method in explaining
the inelastic scattering together with other observables such as elastic
scattering, excitation function and fusion data. We use both microscopic
double-folding and phenomenological deep potentials with shallow imaginary
components. We argue that the solution of the problems for the inelastic
scattering data is not related to the central nuclear potential, but to the
coupling potential between excited states. We present that these problems can
be addressed in a systematic way by using a different shape for the coupling
potential instead of the usual one based on Taylor expansion.Comment: 10 pages, 4 figures, 1 table, Latex:RevTex4 published in J. Phys. G:
Nucl. Part. Phy
Particle dynamics from aerosol flow
Particles with different sizes are modeled under steady- state laminar flow conditions. For this purpose, a CFD numerical simulation is performed to resolve the fluid flow and particles trajectories
Compact Measurement Station for Low Energy Proton Beams
A compact, remote controlled, cost efficient diagnostic station has been
developed to measure the charge, the profile and the emittance for low energy
proton beams. It has been installed and tested in the proton beam line of the
Project Prometheus at SANAEM of the Turkish Atomic Energy Authority.Comment: 7 pages 2 column
Formation of the sural nerve in foetal cadavers
The purpose of this study was to provide a morphologic description and assessmenton the formation level of the sural nerve (SN) and its components. Alsowe aimed to reveal histological features of the SN components. An anatomicalstudy of the formation of the SN was carried out on 100 limbs from 50 embalmedfoetuses. The results showed that the SN was formed by the union ofthe medial sural cutaneous nerve (MSCN) and the peroneal communicatingbranch (PCB) in 71% of the cases (Type A); the MSCN and PCB are branches ofthe tibial and common peroneal nerve (CPN) or lateral sural cutaneous nerves(LSCN), respectively. Formation level of the SN was at the distal third of the legin 43% of the cases, at the middle third of the leg in 46% of the cases, and atthe upper third of the leg in 11% of the cases. The PCB originated in the CPN in68% and the PCB originated in the LSCN in 3% of the cases. The SN wasformed only by the MSCN in 20% of the cases (Type B). Type C was divided intofour subgroups: in the first group the PCB and fibres of the posterior femoralcutaneous nerve joined the MSCN in 4% of cases; in the second group theMSCN, PCB, and sciatic nerve did not unite and coursed separately in 1% ofcases; in the third group the SN arose directly from the sciatic nerve alone andthe MSCN made a little contribution in 2% of cases; and in the fourth groupthe PCB, fibres of the sciatic nerve, and the MSCN formed the SN in 1% of thecases. The SN was formed only by the PCB in 1% of the cases (Type D). Distancesof the formation level of the SN to the intercondylar line and the lateralmalleolus were measured and also noted. A detailed knowledge of the anatomyof the SN and its contributing nerves are important in many interventionalprocedures
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