The synthesis and characterisation of four new antimony sulphides incorporating transition-metal complexes

Four new antimony sulphides, [T(dien)(2)]Sb6S10 center dot xH(2)O [T = Ni (1), Co (2) x approximate to 0.45], [Co(en)(3)]SbsSI(3) (3) and [Ni(en)(3)]Sb12S19 (4), have been synthesised under solvothermal conditions. In compounds (1) - (3), Sb12S228- secondary building units are connected to form layered structures. In (1) and (2), Sb-6 S-2- layers containing Sb16S16 heterorings are separated by [T(dien]2](2+) cations, whilst in (3), Sb8 S2- layers 10 13 contain [Co(en)3]2+ cations within large Sb22S22 pores. Compound (4) adopts a three-dimensional structure in which [Ni(en)3 12 cations lie within ca. 5 A wide channels. (c) 2007 Elsevier Ltd. All rights reserved.

The transition of the Polish real estate market within a Central and Eastern European context

The real estate market in Poland is a relatively immature market, but one that has been experiencing substantial transformation. The development of the market has been encouraged by a number of factors, including changes arising as a result of new legislation and the migration of capital between capital markets. The progress of the real estate sector towards a western style competitive market has taken place within the gradual transformation of the Polish economy into a free market economy. As investment grade property is in relatively short supply in Poland, investors consider opportunities within the wider CEE block. An analysis of the risk-return characteristics of the three largest CEE real estate markets namely, Poland, Hungary and Czech Republic, shows that the returns in these markets have been negatively correlated with the UK. As these economies and markets evolve, and being part of the wider EU trading block, their economic performance will slowly converge and become more synchronized with their western counterparts. However, the catch-up of the CEE markets to western European performance cycles will be protracted and consequently there are likely to be significant ongoing portfolio risk reduction opportunities

Turning on the alarm: the neural mechanisms of the transition from innocuous to painful sensation

The experience of pain occurs when the level of a stimulus is sufficient to elicit a marked affective response, putatively to warn the organism of potential danger and motivate appropriate behavioral responses. Understanding the biological mechanisms of the transition from innocuous to painful levels of sensation is essential to understanding pain perception as well as clinical conditions characterized by abnormal relationships between stimulation and pain response. Thus, the primary objective of this study was to characterize the neural response associated with this transition and the correspondence between that response and subjective reports of pain. Towards this goal, this study examined BOLD response profiles across a range of temperatures spanning the pain threshold. 14 healthy adults underwent functional magnetic resonance imaging (fMRI) while a range of thermal stimuli (44-49oC) were applied. BOLD responses showed a sigmoidal profile along the range of temperatures in a network of brain regions including insula and mid- cingulate, as well as a number of regions associated with motor responses including ventral lateral nuclei of the thalamus, globus pallidus and premotor cortex. A sigmoid function fit to the BOLD responses in these regions explained up to 85% of the variance in individual pain ratings, and yielded an estimate of the temperature of steepest transition from non-painful to painful heat that was nearly identical to that generated by subjective ratings. These results demonstrate a precise characterization of the relationship between objective levels of stimulation, resulting neural activation, and subjective experience of pain and provide direct evidence for a neural mechanism supporting the nonlinear transition from innocuous to painful levels along the sensory continuum.

Revealing ensemble state transition patterns in multi-electrode neuronal recordings using hidden Markov models

In order to harness the computational capacity of dissociated cultured neuronal networks, it is necessary to understand neuronal dynamics and connectivity on a mesoscopic scale. To this end, this paper uncovers dynamic spatiotemporal patterns emerging from electrically stimulated neuronal cultures using hidden Markov models (HMMs) to characterize multi-channel spike trains as a progression of patterns of underlying states of neuronal activity. However, experimentation aimed at optimal choice of parameters for such models is essential and results are reported in detail. Results derived from ensemble neuronal data revealed highly repeatable patterns of state transitions in the order of milliseconds in response to probing stimuli.

Easing transition and promoting a positive student experience within an international partnership scheme for British and Chinese teachers

This article investigates the needs and challenges of a group of Chinese secondary school teachers in their transition to postgraduate studies in the UK in the context of a British-Chinese partnership. The strategies and efforts of the host institution, local community and the Chinese students themselves to help ease the transition and promote a positive student experience are discussed. The article highlights the sociological processes of international postgraduate student transition and contributes to our understanding of issues of student support pertinent to international partnership arrangements.

Transition of pupils from Key Stage 2 to 3 deemed gifted and talented in mathematics: an initial study

In this article Geoff Tennant and Dave Harries report on the early stages of a research project looking to examine the transition from Key Stage (KS) 2 to 3 of children deemed Gifted and Talented (G&T) in mathematics. An examination of relevant literature points towards variation in definition of key terms and underlying rationale for activities. Preliminary fieldwork points towards a lack of meaningful communication between schools, with primary school teachers in particular left to themselves to decide how to work with children deemed G&T. Some pointers for action are given, along with ideas for future research and a request for colleagues interested in working with us to get in touch.

Reversible thermal transition of polydiacetylene based on KTTKS collagen sequence

Here we explore the physico-chemical properties of a peptide amphiphile obtained by chemical conjugation of the collagenstimulating peptide KTTKS with 10,12-pentacosadiynoic acid which photopolymerizes as a stable and extended polydiacetylene. We investigate the self-assembly of this new polymer and rationalize its peculiar behavior in terms of a thermal conformational transition. Surprisingly, this polymer shows a thermal transition associated with a non-cooperative increase in b-sheet content at high temperature.

The relationship between El Niño and the western North Pacific summer climate in a coupled GCM: role of the transition of El Niño decaying phases

This study investigates the impacts of the transition of El Niño decaying phases on the western North Pacific anticyclone (WNPAC) anomalies in the subsequent summer with a coupled GCM. The modeling results suggest that the El Niños with short decaying phases lead to significant WNPAC anomalies in the following summer, which are contributed to mainly by the El Niños followed by La Niñas, in comparison with those not followed by La Niñas. In contrast, the long decaying cases are associated with the disappearance of WNPAC anomalies in the summer. These differences in the WNP circulation anomalies can be explained by the different configurations of simultaneous SSTs in the Indian Ocean and in the central and eastern tropical Pacific: positive SSTs in the former region and negative ones in the latter region constructively induce significant WNPAC anomalies for the short decaying cases, while the roles of positive SSTs in both regions for the long decaying cases work destructively and lead to weak WNP circulation anomalies. Further analysis indicates that the different lengths of El Niño decaying phases are predicted by the strength of Indian Ocean SSTs in the mature winter. The warmer wintertime Indian Ocean SSTs favor the anomalous easterly wind over the western and central equatorial Pacific in the subsequent summer, leading to a short decaying of El Niño. Thus, the strength of wintertime Indian Ocean SSTs is one of the important factors that affect the length of El Niño decaying phase and resultant WNPAC anomalies in the following summer.

All-or-none (or something in between) transition of DNA

DNA compaction can be caused by multivalent ions as condensing agents. Both discontinuous (all-or-none) and continuous (pearl-necklace structure) transitions have been observed in experiments as the concentration of the condensing agent was increased. We have investigated the DNA transition by analytical calculations in the infinite-chain limit. A mechanism for pearl-necklace structures could be a combinatorial entropy term, which favours a mixture of globules and coils in a single chain. However, when a surface term is taken into account, it gives rise to a discontinuous transition. We also consider the role of surface charges on the globule.

Transition from an anti-phase error-correction-mode to a synchronization mode in the mutual hand tracking

Proactive motion in hand tracking and in finger bending, in which the body motion occurs prior to the reference signal, was reported by the preceding researchers when the target signals were shown to the subjects at relatively high speed or high frequencies. These phenomena indicate that the human sensory-motor system tends to choose an anticipatory mode rather than a reactive mode, when the target motion is relatively fast. The present research was undertaken to study what kind of mode appears in the sensory-motor system when two persons were asked to track the hand position of the partner with each other at various mean tracking frequency. The experimental results showed a transition from a mutual error-correction mode to a synchronization mode occurred in the same region of the tracking frequency with that of the transition from a reactive error-correction mode to a proactive anticipatory mode in the mechanical target tracking experiments. Present research indicated that synchronization of body motion occurred only when both of the pair subjects operated in a proactive anticipatory mode. We also presented mathematical models to explain the behavior of the error-correction mode and the synchronization mode.

The troposphere-to-stratosphere transition in kinetic energy spectra and nonlinear spectral fluxes as seen in ECMWF analyses

Global horizontal wavenumber kinetic energy spectra and spectral fluxes of rotational kinetic energy and enstrophy are computed for a range of vertical levels using a T799 ECMWF operational analysis. Above 250 hPa, the kinetic energy spectra exhibit a distinct break between steep and shallow spectral ranges, reminiscent of dual power-law spectra seen in aircraft data and high-resolution general circulation models. The break separates a large-scale ‘‘balanced’’ regime in which rotational flow strongly dominates divergent flow and a mesoscale ‘‘unbalanced’’ regime where divergent energy is comparable to or larger than rotational energy. Between 230 and 100 hPa, the spectral break shifts to larger scales (from n 5 60 to n 5 20, where n is spherical harmonic index) as the balanced component of the flow preferentially decays. The location of the break remains fairly stable throughout the stratosphere. The spectral break in the analysis occurs at somewhat larger scales than the break seen in aircraft data. Nonlinear spectral fluxes defined for the rotational component of the flow maximize between about 300 and 200 hPa. Large-scale turbulence thus centers on the extratropical tropopause region, within which there are two distinct mechanisms of upscale energy transfer: eddy–eddy interactions sourcing the transient energy peak in synoptic scales, and zonal mean–eddy interactions forcing the zonal flow. A well-defined downscale enstrophy flux is clearly evident at these altitudes. In the stratosphere, the transient energy peak moves to planetary scales and zonal mean–eddy interactions become dominant.

Self-assembly of a peptide amphiphile: transition from nanotape fibrils to micelles

A thermal transition is observed in the peptide amphiphile C16-KTTKS (TFA salt) from nanotapes at 20 degrees C to micelles at higher temperature (the transition temperature depending on concentration). The formation of extended nanotapes by the acetate salt of this peptide amphiphile, which incorporates a pentapeptide from type I procollagen, has been studied previously [V. Castelletto et al., Chem. Commun., 2010, 46, 9185]. Here, proton NMR and SAXS provide evidence for the TFA salt spherical micelles at high temperature. The phase behavior, with a Krafft temperature separating insoluble aggregates (extended nanotapes) at low temperature from the high temperature micellar phase resembles that for conventional surfactants, however this has not previously been reported for peptide amphiphiles.

Mechanism for synchronized motion between two humans in mutual tapping experiments: Transition from alternative mode to synchronization mode

We performed mutual tapping experiments between two humans to investigate the conditions required for synchronized motion. A transition from an alternative mode to a synchronization mode was discovered under the same conditions when a subject changed from a reactive mode to an anticipation mode in single tapping experiments. Experimental results suggest that the cycle time for each tapping motion is tuned by a proportional control that is based on synchronization errors and cycle time errors. As the tapping frequency increases, the mathematical model based on the feedback control in the sensory-motor closed loop predicts a discrete mode transition as the gain factors of the proportional control decease. The conditions of the synchronization were shown as a consequence of the coupled dynamics based on the subsequent feedback loop in the sensory-motor system.

Reversible helical unwinding transition of a self-assembling peptide amphiphile

A designed peptide amphiphile C16-KKFFVLK self-assembles into nanotubes and helical ribbons in aqueous solution at room temperature. A remarkable unwinding transition, leading to twisted tapes, is observed on heating. Nanotubes and ribbons re-form on cooling.