Content of radioactive elements of the small mammal biological material in the anthropogenic impact zones and background areas

В данной статье рассматриваются особенности содержания химических элементов урана (U), и тория (Th), изученные методом инструментального нейтронно-активационного анализа, в пробах эмбриона, плаценты и печени мелкого млекопитающего вида Полевка рыжая (Myodes glareolus), отобранных около крупного медеплавильного завода (г. Ревда, Свердловская область). As the title implies the article describes a specific of content of chemical elements uranium (U), and thorium (Th), studied with Instrumental neutron-activation analysis in samples of embryo, placenta and liver of small mammal species Vole red (Myodes glareolus), sampled near large copper-smelting plant (Revda, Sverdlovsk region)

Incidence, mechanisms, and consequences of adaptive habitat selection by the dickcissel (Spiza americana)

Most animals display preferences when faced with the choice of habitats in which to settle. A key question that arises from these behaviors is whether preferences represent adaptive habitat selection—do animals occupying preferred habitats incur fitness benefits? A prediction based on natural selection suggests that preferences should increase fitness, but this prediction is not always supported. Several factors may cause preference-fitness mismatches, including temporal variability of variables driving reproductive success, tradeoffs across spatial scales or among fitness components, and anthropogenic changes disrupting historic relationships between habitat preferences and habitat quality. This dissertation presents three studies I conducted on the habitat preferences and reproductive success of dickcissels (Spiza americana) in the Grand River Grasslands of southern Iowa. I first tested for signals of adaptive habitat selection, examining whether male and female birds’ preferences among territories and larger habitat patches improve their ability to attract mates, avoid parasitism by brown-headed cowbirds (Molothrus ater), and produce robust offspring. Dickcissels engaged in adaptive habitat selection in some respects—such as preferring territories associated with high offspring condition and patches where parasitism was infrequent—but there was strong variation across sexes, spatial scales, years, and reproductive components. Next, I examined whether dickcissels used vegetation cues to select high-quality habitats. I measured multiple vegetation features in territories and patches and compared these to dickcissel habitat preferences and fitness metrics. Although dickcissels preferred specific vegetation features (again, with variation across sexes and scales), and specific vegetation features were associated with fitness (again, with variation across reproductive metrics), I found limited evidence that vegetation mediated adaptive habitat selection. Finally, I further studied the impacts of vegetation on dickcissel reproduction by focusing on the relative impacts of human-altered habitat components (invasive plants and broad-scale land cover) on nest survival and parasitism. I found that an invasive grass common throughout the Midwest region (tall fescue, Schedonorus arundinaceus) reduced nest survival and increased parasitism, whereas increasing woodland cover in the landscape reduced parasitism. In these studies, I illuminated proximate and ultimate forces shaping the reproductive ecology of dickcissels. I demonstrated that habitat preferences—and thus the spatiotemporal dynamics of population distributions—benefit specific components of reproductive success at particular spatial scales, while benefits to other reproductive metrics are variable across time. These results show that because fitness results from a wide variety of ecological processes, accurate assessments of adaptive habitat selection require a complex perspective. In addition, I have contributed to our knowledge of how vegetation influences dickcissel settlement patterns, while showing that preferred vegetation components have little influence on fitness. Other mechanisms (e.g., site fidelity, conspecific attraction, food availability, predator abundance) may thus play a stronger role in facilitating adaptive habitat selection. At the same time, I found strong evidence that vegetation altered by human activity shapes dickcissel habitat quality, and my results suggest that controlling invasive tall fescue may improve dickcissel nest success

The Higgs as a Portal to Plasmon-like Unparticle Excitations

12 LaTeX pages, 2 figures.-- Published in: JHEP04(2008)028.-- Final full-text version available at: http://dx.doi.org/10.1088/1126-6708/2008/04/028.A renormalizable coupling between the Higgs and a scalar unparticle operator O_U of non-integer dimension d_U<2 triggers, after electroweak symmetry breaking, an infrared divergent vacuum expectation value for O_U. Such IR divergence should be tamed before any phenomenological implications of the Higgs-unparticle interplay can be drawn. In this paper we present a novel mechanism to cure that IR divergence through (scale-invariant) unparticle self-interactions, which has properties qualitatively different from the mechanism considered previously. Besides finding a mass gap in the unparticle continuum we also find an unparticle pole reminiscent of a plasmon resonance. Such unparticle features could be explored experimentally through their mixing with the Higgs boson.Work supported in part by the European Commission under the European Union through the Marie Curie Research and Training Networks “Quest for Unification” (MRTN-CT- 2004-503369) and “UniverseNet” (MRTN-CT-2006-035863); by the Spanish Consolider- Ingenio 2010 Programme CPAN (CSD2007-0042); by a Comunidad de Madrid project (P-ESP-00346) and by CICYT, Spain, under contracts FPA 2007-60252 and FPA 2005-02211

The cognitive neuroscience of prehension: recent developments

Prehension, the capacity to reach and grasp, is the key behavior that allows humans to change their environment. It continues to serve as a remarkable experimental test case for probing the cognitive architecture of goal-oriented action. This review focuses on recent experimental evidence that enhances or modifies how we might conceptualize the neural substrates of prehension. Emphasis is placed on studies that consider how precision grasps are selected and transformed into motor commands. Then, the mechanisms that extract action relevant information from vision and touch are considered. These include consideration of how parallel perceptual networks within parietal cortex, along with the ventral stream, are connected and share information to achieve common motor goals. On-line control of grasping action is discussed within a state estimation framework. The review ends with a consideration about how prehension fits within larger action repertoires that solve more complex goals and the possible cortical architectures needed to organize these actions

Mirror Symmetric Bimanual Movement Priming Can Increase Corticomotor Excitability and Enhance Motor Learning

Repetitive mirror symmetric bilateral upper limb may be a suitable priming technique for upper limb rehabilitation after stroke. Here we demonstrate neurophysiological and behavioural after-effects in healthy participants after priming with 20 minutes of repetitive active-passive bimanual wrist flexion and extension in a mirror symmetric pattern with respect to the body midline (MIR) compared to an control priming condition with alternating flexion-extension (ALT). Transcranial magnetic stimulation (TMS) indicated that corticomotor excitability (CME) of the passive hemisphere remained elevated compared to baseline for at least 30 minutes after MIR but not ALT, evidenced by an increase in the size of motor evoked potentials in ECR and FCR. Short and long-latency intracortical inhibition (SICI, LICI), short afferent inhibition (SAI) and interhemispheric inhibition (IHI) were also examined using pairs of stimuli. LICI differed between patterns, with less LICI after MIR compared with ALT, and an effect of pattern on IHI, with reduced IHI in passive FCR 15 minutes after MIR compared with ALT and baseline. There was no effect of pattern on SAI or FCR H-reflex. Similarly, SICI remained unchanged after 20 minutes of MIR. We then had participants complete a timed manual dexterity motor learning task with the passive hand during, immediately after, and 24 hours after MIR or control priming. The rate of task completion was faster with MIR priming compared to control conditions. Finally, ECR and FCR MEPs were examined within a pre-movement facilitation paradigm of wrist extension before and after MIR. ECR, but not FCR, MEPs were consistently facilitated before and after MIR, demonstrating no degradation of selective muscle activation. In summary, mirror symmetric active-passive bimanual movement increases CME and can enhance motor learning without degradation of muscle selectivity. These findings rationalise the use of mirror symmetric bimanual movement as a priming modality in post-stroke upper limb rehabilitation