Electromagnetic form factors of the nucleon in effective field theory

We calculate the electromagnetic form factors of the nucleon to third chiral order in manifestly Lorentz-invariant effective field theory. The rho and omega mesons as well as the Delta(1232) resonance are included as explicit dynamical degrees of freedom. To obtain a self-consistent theory with respect to constraints we consider the proper relations among the couplings of the effective Lagrangian. For the purpose of generating a systematic power counting, the extended on-mass-shell renormalization scheme is applied in combination with the small-scale expansion. The results for the electric and magnetic Sachs form factors are analyzed in terms of experimental data and compared to previous findings in the framework of chiral perturbation theory. The pion-mass dependence of the form factors is briefly discussed.Comment: 26 pages, 9 figure

Environmental changes and violent conflict

This letter reviews the scientific literature on whether and how environmental changes affect the risk of violent conflict. The available evidence from qualitative case studies indicates that environmental stress can contribute to violent conflict in some specific cases. Results from quantitative large-N studies, however, strongly suggest that we should be careful in drawing general conclusions. Those large-N studies that we regard as the most sophisticated ones obtain results that are not robust to alternative model specifications and, thus, have been debated. This suggests that environmental changes may, under specific circumstances, increase the risk of violent conflict, but not necessarily in a systematic way and unconditionally. Hence there is, to date, no scientific consensus on the impact of environmental changes on violent conflict. This letter also highlights the most important challenges for further research on the subject. One of the key issues is that the effects of environmental changes on violent conflict are likely to be contingent on a set of economic and political conditions that determine adaptation capacity. In the authors' view, the most important indirect effects are likely to lead from environmental changes via economic performance and migration to violent conflict. © 2012 IOP Publishing Ltd

Proprioceptive isokinetic exercise test

Proprioception, the reception of stimuli within the body that indicates position, is an important mechanism for optimal human performance. People exposed to prolonged bed rest, microgravity, or other deconditioning situations usually experience reduced proprioceptor and kinesthetic stimuli that compromise body balance, posture, and equilibrium. A new proprioceptive test is described that utilizes the computer-driven LIDO isokinetic ergometer. An overview of the computer logic, software, and testing procedure for this proprioceptive test, which can be performed with the arms or legs, is described

A Collaborative Filtering Approach for Protein-Protein Docking Scoring Functions

A protein-protein docking procedure traditionally consists in two successive tasks: a search algorithm generates a large number of candidate conformations mimicking the complex existing in vivo between two proteins, and a scoring function is used to rank them in order to extract a native-like one. We have already shown that using Voronoi constructions and a well chosen set of parameters, an accurate scoring function could be designed and optimized. However to be able to perform large-scale in silico exploration of the interactome, a near-native solution has to be found in the ten best-ranked solutions. This cannot yet be guaranteed by any of the existing scoring functions

The size of the proton - closing in on the radius puzzle

We analyze the recent electron-proton scattering data from Mainz using a dispersive framework that respects the constraints from analyticity and unitarity on the nucleon structure. We also perform a continued fraction analysis of these data. We find a small electric proton charge radius, r_E^p = 0.84_{-0.01}^{+0.01} fm, consistent with the recent determination from muonic hydrogen measurements and earlier dispersive analyses. We also extract the proton magnetic radius, r_M^p = 0.86_{-0.03}^{+0.02} fm, consistent with earlier determinations based on dispersion relations.Comment: 4 pages, 2 figures, fit improved, small modifications, section on continued fractions modified, conclusions on the proton charge radius unchanged, version accepted for publication in European Physical Journal

Levels of rna for TNF-α and receptors during the prereplicative period of liver regeneration

During the prereplicative period of liver regeneration the changes of the tnRNA contents for tumor necrosis factor-α (TNF-α) and its receptors were examined in total liver RNA with the help of reverse transcriptase-polymera.se chain reaction (RT-PCR) and compared with those after sham operation or stimulation with lipopolysaccharide (LPS). In regenerating liver all the changes are nearly synchronous with a slight delay (or the TNF receptor RNAs. The mRNA levels reach their maximum at 1–3 h after operation and exceed the values for intact animals about ten-fold. The corresponding changes induced by sham operation are quantitatively less than those in the regenerating liver and manifest themselves at the end of the prereplicative period. LPS stimulation induced an increase of TNF-α and TNF receptor production comparable with during regeneration. Analysis of the expression of the 55 kDa TNF receptor revealed qualitative changes, e. g. an increased polyadenylation and an imbalance between the amplification of the whole molecule and its 5'-terminal half pointing to as yet unidentified changes at the 3' end of the molecule.Протягом пререплікативного періоду регенерації печінки спостерігалися зміни, вмісту мРНК фактора некроза пухлини (TNF-α) i його рецепторів у сумарній РНК печінки за допомогою зворотної транскрипції та полімеразної ланцюгової реакції. Для порівняння ці ж величини визначали у печінці теля несправжньої операції або ліпополісахаридної стимуляції. У регенеруючі печінці вci зміни майже синхронні, з невели­ким запізненням для РНК рецепторів TNF. Рівні мРНК досягають максимальних значень через 1–3 год. теля операції i приблизно у 10 разів перевищують такі для штатних тварин. Зміни, викликані несправжньою операщею, меньші за величиною, ніж при регенерації, i проявляються у кінці пререплікативного перюду. Стимуляція ліпополісахаридами призводить до росту продукції TNF-α i його рецепторів, порівнянно з таким при регенерації. Аналіз мРНК рецептора TNF масою 55 000 засвідчив якісні зміни, у тому числі збільшення поліаденілювання, i невідповідність ампліфікації щодо молекули та и частини, прилеглої до 5'-кінця, що вказує на поки що не визначені зміни на З'-кінці молекули.В течении пререпликативного периода регенерации печени наблюдались изменения, содержания мРНК фактора некроза опухоли (TNF α ) и его рецепторов в суммарной РНК печени с помощью обратной транскрипции и полимеразной цепной реакции. Для сравнения эти же величины определяли в печени теленка псевдооперации или липополисахаридный стимуляции. В регенерирующие печени вcе изменения почти синхронные, с небольшим опозданием для РНК рецепторов TNF . Уровни мРНК достигают максимальных значений через 1–3 час. теленок операции i примерно в 10 раз превышают таковые для штатных животных. Изменения, вызванные ложной операщею , меньшие по величине , чем при регенерации, и проявляются в конце пререпликативного периода . Стимуляция липополисахаридами приводит к росту продукции TNF -α и его рецепторов, по сравнению с таковым при регенерации. Анализ мРНК рецептора TNF массой 55000 показал качественные изменения, в том числе увеличение полиаденилирования , и несоответствие амплификации по молекулы и и части , прилегающей к 5' - конца , что указывает на пока не определены изменения на З' - конце молекулы

A Large-Scale FPGA-Based Trigger and Dead-Time Free DAQ System for the Kaos Spectrometer at MAMI

The Kaos spectrometer is maintained by the A1 collaboration at the Mainz Microtron MAMI with a focus on the study of (e,e'K^+) coincidence reactions. For its electron-arm two vertical planes of fiber arrays, each comprising approximately 10 000 fibers, are operated close to zero degree scattering angle and in close proximity to the electron beam. A nearly dead-time free DAQ system to acquire timing and tracking information has been installed for this spectrometer arm. The signals of 144 multi-anode photomultipliers are collected by 96-channel front-end boards, digitized by double-threshold discriminators and the signal time is picked up by state-of-the-art F1 time-to-digital converter chips. In order to minimize background rates a sophisticated trigger logic was implemented in newly developed Vuprom modules. The trigger performs noise suppression, signal cluster finding, particle tracking, and coincidence timing, and can be expanded for kinematical matching (e'K^+) coincidences. The full system was designed to process more than 4 000 read-out channels and to cope with the high electron flux in the spectrometer and the high count rate requirement of the detectors. It was successfully in-beam tested at MAMI in 2009.Comment: Contributed to 17th IEEE Real Time Conference (RT10), Lisbon, 24-28 May 201