Pumping current of a Luttinger liquid with finite length

We study transport properties in a Tomonaga-Luttinger liquid in the presence of two time-dependent point like weak impurities, taking into account finite-length effects. By employing analytical methods and performing a perturbation theory, we compute the backscattering pumping current (I_bs) in different regimes which can be established in relation to the oscillatory frequency of the impurities and to the frequency related to the length and the renormalized velocity (by the electron-electron interactions) of the charge density modes. We investigate the role played by the spatial position of the impurity potentials. We also show how the previous infinite length results for I_bs are modified by the finite size of the system.Comment: 9 pages, 7 figure

An Animal Model of Emotional Blunting in Schizophrenia

Schizophrenia is often associated with emotional blunting—the diminished ability to respond to emotionally salient stimuli—particularly those stimuli representative of negative emotional states, such as fear. This disturbance may stem from dysfunction of the amygdala, a brain region involved in fear processing. The present article describes a novel animal model of emotional blunting in schizophrenia. This model involves interfering with normal fear processing (classical conditioning) in rats by means of acute ketamine administration. We confirm, in a series of experiments comprised of cFos staining, behavioral analysis and neurochemical determinations, that ketamine interferes with the behavioral expression of fear and with normal fear processing in the amygdala and related brain regions. We further show that the atypical antipsychotic drug clozapine, but not the typical antipsychotic haloperidol nor an experimental glutamate receptor 2/3 agonist, inhibits ketamine's effects and retains normal fear processing in the amygdala at a neurochemical level, despite the observation that fear-related behavior is still inhibited due to ketamine administration. Our results suggest that the relative resistance of emotional blunting to drug treatment may be partially due to an inability of conventional therapies to target the multiple anatomical and functional brain systems involved in emotional processing. A conceptual model reconciling our findings in terms of neurochemistry and behavior is postulated and discussed

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia's floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region's floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon's tree diversity and its function.Naturali

Work-life balance, management practices and productivity

Do “Anglo-Saxon” management practices generate higher productivity only at the expense of lousy work-life balance (WLB) for workers? Many critics of “neo-libéralisme sauvage” have argued that increased competition from globalisation is damaging employees’ quality of life. Others have argued the opposite that improving work-life balance is actually a competitive tool that companies can use to raise productivity. We try to shed some empirical light on these issues using an innovative survey tool to collect new data on management and work-life balance practices from 732 medium sized manufacturing firms in the US, France, Germany and the UK. First, we show that our measure of work-life balance is a useful summary of a range of policies in the firm – family-friendly policies, flexible working, shorter hours, more holidays, subsidised childcare, etc. We show that this worklife balance measure is significantly associated with better management. Firms in environments that are more competitive and/or who are more productive, however, do not have significantly worse work-life balance for their workers. These findings are inconsistent with the view that competition, globalisation and “Anglo-Saxon” management practices are intrinsically bad for the work-life balance of workers. On the other hand, neither are these findings supportive of the optimistic “winwin” view that work-life balance improves productivity in its own right. Rather we find support for a “hybrid” theory that work-life balance is a choice for managers that is compatible with low or high productivity