In the present article we give a brief overview of the theories of the 0.7 anomaly of the ballistic conductance. The special attantion is given to the concept of a fractional quantization of the ballistic conductance arising from exchange interaction of the Heisenberg type between the carrier localized in the region of the quantum point contact and freely propagating carriers in electron and hole systems. ----- Brotask\"ommtun skotlei{\eth}ninnar \'i einv\'i{\eth}um rafeinda og holukerfum \'I grein {\th}essari ver{\eth}ur sk\"ommtun skotlei{\eth}ninnar \'i einv\'i{\eth}um kerfum \'utsk\'yr{\eth} og fari{\eth} yfir n\'yjustu og helstu fr{\ae}{\eth}il\'ik\"on \'a svi{\eth}i \LDQ 0,7 fr\'aviksins \RDQ og tengdra fyrirbrig{\eth}a \'i einv\'i{\eth}um rafeinda og holukerfum. Vi{\eth} kynnum hugmynd okkar um a{\eth} brotask\"ommtun skotlei{\eth}ninnar lei{\eth}i af Heisenberg skiptaverkun milli sta{\eth}bundins rafbera \'i skammtapunktsnertunni og frj\'alsra lei{\eth}nirafbera og s\'ynum fram \'a a{\eth} heg{\eth}un lei{\eth}ninnar er eigindlega \'ol\'ik milli rafeinda og holukerfa.

{p=Data assimilation has been used in meteorology and oceanography to combine dynamical models and observations to predict changes in state variables. Along similar lines of development, we have created a geomagnetic data assimilation system, MoSST-DAS, which includes a numerical geodynamo model, a suite of geomagnetic and paleomagnetic field models dating back to 5000 BCE, and a data assimilation component using a sequential assimilation algorithm. To reduce systematic errors arising from the geodynamo model, a prediction-correction iterative algorithm is applied for more accurate forecasts. This system and the new algorithm are tested with 7-year geomagnetic forecasts. The results are compared independently with CHAOS and IGRF field models, and they agree very well. Utilizing the geomagnetic field models up to 2009, we provide our prediction of 5-year mean secular variation (SV) for the period 2010–2015 up to degree L = 8. Our prediction is submitted to IGRF-11 as a candidate SV model., h1=Abstract}

Stem cell therapies for neurodegenerative disorders require accurate delivery of the transplanted cells to the sites of damage. Numerous studies have established that fluid injections to the hippocampus can induce lesions in the dentate gyrus (DG) that lead to cell death within the upper blade. Using a mouse model of temporal lobe epilepsy, we previously observed that embryonic stem cell-derived neural progenitors (ESNPs) survive and differentiate within the granule cell layer after stereotaxic delivery to the DG, replacing the endogenous cells of the upper blade. To investigate the mechanisms for ESNP migration and repair in the DG, we examined the role of the chemokine CXCL12 in mice subjected to kainic acid-induced seizures. We now show that ESNPs transplanted into the DG show extensive migration through the upper blade, along the septotemporal axis of the hippocampus. Seizures upregulate CXCL12 and infusion of the CXCR4 antagonist AMD3100 by osmotic minipump attenuated ESNP migration. We also demonstrate that seizures promote the differentiation of transplanted ESNPs toward neuronal rather than astrocyte fates. These findings suggest that ESNPs transplanted into the adult rodent hippocampus migrate in response to cytokine-mediated signals.

We study general models of holographic superconductors away from the probe limit. We find that the backreaction of the spacetime can bring richer physics in the phase transition. Moreover we observe that the ratio $\omega_g/T_c$ changes with the strength of the backreaction and is not a universal constant.

The essentially unique reduction of the Euler-Poinsot problem may be performed in different sets of variables. Action-angle variables are usually preferred because of their suitability for approaching perturbed rigid-body motion. But they are just one among the variety of sets of canonical coordinates that integrate the problem. We present an alternate set of variables that, while allowing for similar performances than action-angles in the study of perturbed problems, show an important advantage over them: Their transformation from and to Andoyer variables is given in explicit form.

This short note presents a peculiar generalization of the Riemann hypothesis, as the action of the permutation group on the elements of continued fractions. The problem is difficult to attack through traditional analytic techniques, and thus this note focuses on providing a numerical survey. These results indicate a broad class of previously unexamined functions may obey the Riemann hypothesis in general, and even share the non-trivial zeros in particular.

{p=[Background, Men who have sex with men (MSM) remain the group most at risk of acquiring HIV in the UK and new HIV prevention strategies are needed. In this paper, we examine what contact MSM currently have with HIV prevention activities and assess the extent to which these could be utilised further., Methods, Anonymous, self-complete questionnaires and Orasure™ oral fluid collection kits were distributed to men visiting the commercial gay scenes in Glasgow and Edinburgh in April/May 2008. 1508 men completed questionnaires (70.5% response rate) and 1277 provided oral fluid samples (59.7% response rate); 1318 men were eligible for inclusion in the analyses., Results, 82.5% reported some contact with HIV prevention activities in the past 12 months, 73.1% obtained free condoms from a gay venue or the Internet, 51.1% reported accessing sexual health information (from either leaflets in gay venues or via the Internet), 13.5% reported talking to an outreach worker and 8.0% reported participating in counselling on sexual health or HIV prevention. Contact with HIV prevention activities was associated with frequency of gay scene use and either HIV or other STI testing in the past 12 months, but not with sexual risk behaviours. Utilising counselling was also more likely among men who reported having had an STI in the past 12 months and HIV-positive men., Conclusions, Men at highest risk, and those likely to be in contact with sexual health services, are those who report most contact with a range of current HIV prevention activities. Offering combination prevention, including outreach by peer health workers, increased uptake of sexual health services delivering behavioural and biomedical interventions, and supported by social marketing to ensure continued community engagement and support, could be the way forward. Focused investment in the needs of those at highest risk, including those diagnosed HIV-positive, may generate a prevention dividend in the long term.], h1=Abstract}

{p=[Background, The synchrony of an organism with both its external and internal environment is critical to well-being and survival. As a result, organisms display daily cycles of physiology and behavior termed circadian rhythms. At the cellular level, circadian rhythms originate via interlocked autoregulatory feedback loops consisting of circadian clock genes and their proteins. These regulatory loops provide the molecular framework that enables the intracellular circadian timing system necessary to generate and maintain subsequent 24 hr rhythms. In the present study we examine the daily control of circadian clock genes and regulation of the inflammatory response by the circadian clock in the spleen., Results, Our results reveal that circadian clock genes as well as proinflammatory cytokines, including Tnfά and IL-1β, display rhythmic oscillations of mRNA abundance over a 24 hr cycle. LPS-induced systemic inflammation applied at midday vs. midnight reveals a differential response of proinflammatory cytokine induction in the spleen, suggesting a daily rhythm of inflammation. Exogenous melatonin administration at midday prior to LPS stimulation conveys pleiotropic effects, enhancing and repressing inflammatory cytokines, indicating melatonin functions as both a pro- and anti-inflammatory molecule in the spleen., Conclusion, In summary, a daily oscillation of circadian clock genes and inflammatory cytokines as well as the ability of melatonin to function as a daily mediator of inflammation provides valuable information to aid in deciphering how the circadian timing system regulates immune function at the molecular level. However, further research is needed to clarify the precise mechanisms by which the circadian clock and melatonin have an impact upon daily immune functions in the periphery.], h1=Abstract}

{p=Methanothermus fervidus Stetter 1982 is the type strain of the genus Methanothermus . This hyperthermophilic genus is of a thought to be endemic in Icelandic hot springs. M. fervidus was not only the first characterized organism with a maximal growth temperature (97°C) close to the boiling point of water, but also the first archaeon in which a detailed functional analysis of its histone protein was reported and the first one in which the function of 2,3-cyclodiphosphoglycerate in thermoadaptation was characterized. Strain V24S^T is of interest because of its very low substrate ranges, it grows only on H_2 + CO_2. This is the first completed genome sequence of the family Methanothermaceae . Here we describe the features of this organism, together with the complete genome sequence and annotation. The 1,243,342 bp long genome with its 1,311 protein-coding and 50 RNA genes is a part of the G enomic E ncyclopedia of B acteria and A rchaea project., h1=Abstract}