Cell‐type specific visualization and biochemical isolation of endogenous synaptic proteins in mice

In recent years, the remarkable molecular complexity of synapses has been revealed, with over 1000 proteins identified in the synapse proteome. Although it is known that different receptors and other synaptic proteins are present in different types of neurons, the extent of synapse diversity across the brain is largely unknown. This is mainly due to the limitations of current techniques. Here we report an efficient method for the purification of synaptic protein‐complexes, fusing a high‐affinity tag to endogenous PSD95 in specific cell types. We also developed a strategy which enables the visualization of endogenous PSD95 with fluorescent‐proteins tag in Cre‐recombinase expressing cells. We demonstrate the feasibility of proteomic analysis of synaptic protein‐complexes and visualization of these in specific cell types. We find that the composition of PSD95‐complexes purified from specific cell types differs from those extracted from tissues with diverse cellular composition. The results suggest that there might be differential interactions in the PSD95‐complexes in different brain regions. We have detected differentially interacting proteins by comparing datasets from the whole hippocampus and the CA3 subfield of the hippocampus. Therefore, these novel conditional PSD95 tagging lines will not only serve as powerful tools for precisely dissecting synapse diversity in specific brain regions and subsets of neuronal cells, but also provide an opportunity to better understand brain region‐ and cell type‐specific alterations associated with various psychiatric/neurological diseases. These newly developed conditional gene‐tagging methods can be applied to many different synaptic proteins and will facilitate research on the molecular complexity of synapses

Mercury (Hg) concentrations in predatory bird livers and eggs as an indicator of changing environmental concentrations: a Predatory Bird Monitoring Scheme (PBMS) report

Concern over the potential health effects of mercury (Hg) has prompted an international agreement, the Minamata Convention on Mercury, that aims to control anthropogenic releases to the environment and reduce potential impacts on humans and wildlife. Monitoring is required to determine to what extent the convention is successful. The PBMS has monitored long-term trends in environmental Hg concentration using raptors and fish-eating birds as sentinels to track changes in exposure. Overall, PBMS monitoring of Hg in predatory birds provides an evidence base by which the impact of the Minamata Convention on environmental mercury concentrations in Britain can be assessed. The current study consisted of four main aims that would help rationalize and inform our long-term Hg monitoring. (i) Updating long-term data for liver Hg concentrations in sparrowhawks, (Accipiter nisus), a sentinel for exposure in lowland terrestrial habitats. (ii) Exploration of the use of alternative tissues for monitoring Hg in sparrowhawks. (iii) Comparison of trends in liver Hg residues in sparrowhawks and kestrels (Falco tinnunculus) to examine if trends in sparrowhawks, which feed on relatively mobile avian prey, reflect those in kestrels which mainly feed on small mammals that are more likely to reflect local contamination. (iv) Completion of work initiated last year to explore the potential for using Hg concentrations in the eggs of inland-feeding golden eagles (Aquila chrysaetos) as a sentinel to track changes in Hg bioavailability and uptake by biota in upland terrestrial systems. We measured liver Hg residues in sparrowhawks that had died in 2013 and 2014 to quantify current Hg exposure in lowland terrestrial habitats and to add to previously reported long-term data. Mercury residues in birds that died in 2013 and 2014 were largely consistent with those reported in recent previous years and were below those associated with mortalities. Three birds had residues higher than those associated with potential adverse effects on reproduction. Analysis of long-term data (1990-2014) indicated liver Hg residues in sparrowhawks vary with age and sex; concentrations are highest in adult males. Starvation also elevates liver Hg concentrations. Taking age and sex into account and using only data for non-starved birds, we investigated temporal trends and found that, although there has been between-year variation in liver Hg concentrations, there has been no consistent upward or downward trend. We used the long-term dataset to define “current baseline” liver Hg concentrations against which levels in future years, and consistent time trends, can be quantitatively and rapidly assessed. We found that total Hg concentrations in sparrowhawk liver, kidney and brain were closely related. We conclude it is possible to transfer our long-term monitoring of Hg in sparrowhawks (including retrospective calculation of “current baseline concentrations”) to analysis of kidney or brain. This would preserve [what are relatively small] sparrowhawk livers for other analyses. Comparison of historic trends in liver Hg in sparrowhawks and kestrels indicated that rates of decline during 1980-1998 were similar in the two species. This is consistent with the premise that sparrrowhawks are as likely as kestrels to be representative of changes in environmental exposure to (and associated bioaccumulation of) Hg in lowland terrestrial systems. The conclusion of our work on Hg concentrations in golden eagle eggs enabled us to quantify a “baseline concentration” for eggs laid by females feeding predominantly on terrestrial prey. We can use this to identify significant changes in future exposure and associated bioaccumulation and thereby use our measurements as sentinel of future change in Hg bioavailability in upland habitats in northern Britain

Ordering and finite-size effects in the dynamics of one-dimensional transient patterns

We introduce and analyze a general one-dimensional model for the description of transient patterns which occur in the evolution between two spatially homogeneous states. This phenomenon occurs, for example, during the Freedericksz transition in nematic liquid crystals.The dynamics leads to the emergence of finite domains which are locally periodic and independent of each other. This picture is substantiated by a finite-size scaling law for the structure factor. The mechanism of evolution towards the final homogeneous state is by local roll destruction and associated reduction of local wavenumber. The scaling law breaks down for systems of size comparable to the size of the locally periodic domains. For systems of this size or smaller, an apparent nonlinear selection of a global wavelength holds, giving rise to long lived periodic configurations which do not occur for large systems. We also make explicit the unsuitability of a description of transient pattern dynamics in terms of a few Fourier mode amplitudes, even for small systems with a few linearly unstable modes.Comment: 18 pages (REVTEX) + 10 postscript figures appende

Nonextensivity in Geological Faults?

Geological fault systems, as the San Andreas fault (SAF) in USA, constitute typical examples of self-organizing systems in nature. In this paper, we have considered some geophysical properties of the SAF system to test the viability of the nonextensive models for earthquakes developed in [Phys. Rev. E {\bf 73}, 026102, 2006]. To this end, we have used 6188 earthquakes events ranging in the magnitude interval $2 < m < 8$ that were taken from the Network Earthquake International Center catalogs (NEIC, 2004-2006) and the Bulletin of the International Seismological Centre (ISC, 1964-2003). For values of the Tsallis nonextensive parameter $q \simeq 1.68$, it is shown that the energy distribution function deduced in above reference provides an excellent fit to the NEIC and ISC SAF data.Comment: 9 pages, 1 figure, standard LaTeX fil

On Perturbative Gravity and Gauge Theory

We review some applications of tree-level (classical) relations between gravity and gauge theory that follow from string theory. Together with $D$-dimensional unitarity, these relations can be used to perturbatively quantize gravity theories, i.e. they contain the necessary information for obtaining loop contributions. We also review recent applications of these ideas showing that N=1 D=11 supergravity diverges, and review arguments that N=8 D=4 supergravity is less divergent than previously thought, though it does appear to diverge at five loops. Finally, we describe field variables for the Einstein-Hilbert Lagrangian that help clarify the perturbative relationship between gravity and gauge theory.Comment: Talk presented at Third Meeting on Constrained Dynamics and Quantum Gravity, Villasimius (Sardinia, Italy) September 13-17, 1999 and at the Workshop on Light-Cone QCD and Nonperturbative Hadron Physics, University of Adelaide (Australia) December 13-22, 1999. Latex, 9 page

Making things happen : a model of proactive motivation

Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc

Formation of superdense hadronic matter in high energy heavy-ion collisions

We present the detail of a newly developed relativistic transport model (ART 1.0) for high energy heavy-ion collisions. Using this model, we first study the general collision dynamics between heavy ions at the AGS energies. We then show that in central collisions there exists a large volume of sufficiently long-lived superdense hadronic matter whose local baryon and energy densities exceed the critical densities for the hadronic matter to quark-gluon plasma transition. The size and lifetime of this matter are found to depend strongly on the equation of state. We also investigate the degree and time scale of thermalization as well as the radial flow during the expansion of the superdense hadronic matter. The flow velocity profile and the temperature of the hadronic matter at freeze-out are extracted. The transverse momentum and rapidity distributions of protons, pions and kaons calculated with and without the mean field are compared with each other and also with the preliminary data from the E866/E802 collaboration to search for experimental observables that are sensitive to the equation of state. It is found that these inclusive, single particle observables depend weakly on the equation of state. The difference between results obtained with and without the nuclear mean field is only about 20\%. The baryon transverse collective flow in the reaction plane is also analyzed. It is shown that both the flow parameter and the strength of the ``bounce-off'' effect are very sensitive to the equation of state. In particular, a soft equation of state with a compressibility of 200 MeV results in an increase of the flow parameter by a factor of 2.5 compared to the cascade case without the mean field. This large effect makes it possible to distinguish the predictions from different theoretical models and to detect the signaturesComment: 55 pages, latex, + 39 figures available upon reques

CPsuperH: a Computational Tool for Higgs Phenomenology in the Minimal Supersymmetric Standard Model with Explicit CP Violation

We provide a detailed description of the Fortran code CPsuperH, a newly--developed computational package that calculates the mass spectrum and decay widths of the neutral and charged Higgs bosons in the Minimal Supersymmetric Standard Model with explicit CP violation. The program is based on recent renormalization-group-improved diagrammatic calculations that include dominant higher--order logarithmic and threshold corrections, b-quark Yukawa-coupling resummation effects and Higgs-boson pole-mass shifts. The code CPsuperH is self--contained (with all subroutines included), is easy and fast to run, and is organized to allow further theoretical developments to be easily implemented. The fact that the masses and couplings of the charged and neutral Higgs bosons are computed at a similar high-precision level makes it an attractive tool for Tevatron, LHC and LC studies, also in the CP-conserving case.Comment: 46 pages, LaTeX, 4 eps figures; the code may be obtained from http://theory.ph.man.ac.uk/~jslee/CPsuperH.html (version as to appear in Comput. Phys. Commun.

Forward production of charged pions with incident π±\pi^{\pm} on nuclear targets measured at the CERN PS

Measurements of the double-differential $\pi^{\pm}$ production cross-section in the range of momentum 0.5 \GeVc \leq p \le 8.0 \GeVc and angle 0.025 \rad \leq \theta \le 0.25 \rad in interactions of charged pions on beryllium, carbon, aluminium, copper, tin, tantalum and lead are presented. These data represent the first experimental campaign to systematically measure forward pion hadroproduction. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. Incident particles, impinging on a 5% nuclear interaction length target, were identified by an elaborate system of beam detectors. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP detector. Results are obtained for the double-differential cross-sections ${{\mathrm{d}^2 \sigma}}/{{\mathrm{d}p\mathrm{d}\Omega}}$ mainly at four incident pion beam momenta (3 \GeVc, 5 \GeVc, 8 \GeVc and 12 \GeVc). The measurements are compared with the GEANT4 and MARS Monte Carlo simulationComment: to be published on Nuclear Physics

Gluino Contribution to Radiative B Decays: Organization of QCD Corrections and Leading Order Results

The gluino-induced contributions to the decay b-> s gamma are investigated in supersymmetric frameworks with generic sources of flavour violation. It is shown that, when QCD corrections are taken into account, the relevant operator basis of the Standard Model effective Hamiltonian gets enlarged to contain: i) magnetic and chromomagnetic operators with a factor of alpha_s and weighted by a quark mass m_b or m_c; ii) magnetic and chromomagnetic operators of lower dimensionality, also containing alpha_s; iii) four-quark operators weighted by a factor alpha_s^2. Numerical results are given, showing the effects of the leading order QCD corrections on the inclusive branching ratio for b-> s gamma. Constraints on supersymmetric sources of flavour violation are derived.Comment: 36 pages including 16 postscript figures; uses epsf; journal version: one ref. added; rephrasing of a couple of paragraph