The non-Abelian state-dependent gauge field in optics

The covariant formulation of the quantum dynamics in CP(1) should lead to the observable geometrodynamical effects for the local dynamical variable of the light polarization states.Comment: 8 pages, 3 figures, LaTe

Current applications of kinetic resolution in the asymmetric synthesis of substituted pyrrolidines

Chiral substituted pyrrolidines are key elements in various biologically active molecules and are therefore valuable synthetic targets. One traditional method towards enantiomerically pure compounds is the application of kinetic resolution. In this review, current KR methodology used in the synthesis of substituted pyrrolidines is surveyed, including enzymatic methods, cycloadditions and reduction of ketones

Face Familiarity and Image-Specific Memory

Face familiarity produces advantages for both memory and matching. By developing an internal representation through repeated experience, viewers extract identity-specific information that aids subsequent recognition. However, researchers have recently argued that this process may also result in a familiarity disadvantage, whereby specific instances of the face are more difficult to remember, perhaps due to this process of prioritising identity- over image-specific information. Although previous experiments found no evidence of this disadvantage in working memory, initial research has demonstrated an effect in longer term storage. Here, we attempted to replicate this finding by focussing on the ability to learn images of a single (un)familiar identity. Our results failed to demonstrate a familiarity disadvantage while replicating the finding that familiarity influences response bias. As researchers continue to investigate how familiarity alters both internal representations and associated processes, it is important to establish which processes may or may not be affected

Dynamic communities in multichannel data: An application to the foreign exchange market during the 2007--2008 credit crisis

We study the cluster dynamics of multichannel (multivariate) time series by representing their correlations as time-dependent networks and investigating the evolution of network communities. We employ a node-centric approach that allows us to track the effects of the community evolution on the functional roles of individual nodes without having to track entire communities. As an example, we consider a foreign exchange market network in which each node represents an exchange rate and each edge represents a time-dependent correlation between the rates. We study the period 2005-2008, which includes the recent credit and liquidity crisis. Using dynamical community detection, we find that exchange rates that are strongly attached to their community are persistently grouped with the same set of rates, whereas exchange rates that are important for the transfer of information tend to be positioned on the edges of communities. Our analysis successfully uncovers major trading changes that occurred in the market during the credit crisis.Comment: 8 pages, 6 figures, accepted for publication in Chao

Resource Control for Synchronous Cooperative Threads

We develop new methods to statically bound the resources needed for the execution of systems of concurrent, interactive threads. Our study is concerned with a \emph{synchronous} model of interaction based on cooperative threads whose execution proceeds in synchronous rounds called instants. Our contribution is a system of compositional static analyses to guarantee that each instant terminates and to bound the size of the values computed by the system as a function of the size of its parameters at the beginning of the instant. Our method generalises an approach designed for first-order functional languages that relies on a combination of standard termination techniques for term rewriting systems and an analysis of the size of the computed values based on the notion of quasi-interpretation. We show that these two methods can be combined to obtain an explicit polynomial bound on the resources needed for the execution of the system during an instant. As a second contribution, we introduce a virtual machine and a related bytecode thus producing a precise description of the resources needed for the execution of a system. In this context, we present a suitable control flow analysis that allows to formulte the static analyses for resource control at byte code level

Evaluation of bifunctional chiral phosphine oxide catalysts for the asymmetric hydrosilylation of ketimines

A series of bifunctional phosphine oxides have been prepared and evaluated as catalysts for the trichlorosilane mediated asymmetric hydrosilylation of ketimines. bis-Phosphine oxides, hydroxy-phosphine oxides, and biaryl phosphine oxides all demonstrated good catalytic activity, but poor to moderate enantioselectivity. A bis-P-chiral phosphine oxide displayed the highest enantioselectivity of 60%

Understanding the barriers to accessing symptom-specific cognitive behavior therapy (CBT) for distressing voices: reflecting on and extending the lessons learnt from the CBT for psychosis literature

The experience of hearing voices ('auditory hallucinations') can cause significant distress and disruption to quality of life for people with a psychosis diagnosis. Psychological therapy in the form of Cognitive Behavior Therapy for psychosis is recommended for the treatment of positive symptoms, including distressing voices, but is rarely available to patients in the UK. Cognitive Behavior Therapy for psychosis has recently evolved with the development of symptom-specific therapies that focus upon only one symptom of psychosis at a time. Preliminary findings from randomized controlled trials suggest that these symptom-specific therapies can be more effective for distressing voices than the use of broad CBT protocols, and have the potential to target voices trans-diagnostically. Whilst this literature is evolving, consideration must be given to the potential for a symptom-specific approach to overcome some of the barriers to delivery of evidence-based psychological therapies within clinical services. These barriers are discussed in relation to the UK mental health services, and we offer suggestions for future research to enhance our understanding of these barriers

Bargmann invariants and off-diagonal geometric phases for multi-level quantum systems -- a unitary group approach

We investigate the geometric phases and the Bargmann invariants associated with a multi-level quantum systems. In particular, we show that a full set of `gauge-invariant' objects for an $n$-level system consists of $n$ geometric phases and ${1/2}(n-1)(n-2)$ algebraically independent 4-vertex Bargmann invariants. In the process of establishing this result we develop a canonical form for U(n) matrices which is useful in its own right. We show that the recently discovered `off-diagonal' geometric phases [N. Manini and F. Pistolesi, Phys. Rev. Lett. 8, 3067 (2000)] can be completely analysed in terms of the basic building blocks developed in this work. This result liberates the off-diagonal phases from the assumption of adiabaticity used in arriving at them.Comment: 13 pages, latex, no figure

Overcoming challenges in delivering integrated motivational interviewing and cognitive behavioural therapy for bipolar disorder with co-morbid alcohol use:Therapist perspectives

Background: Alcohol misuse is common in bipolar disorder and is associated with worse outcomes. A recent study evaluated integrated motivational interviewing and cognitive behavioural therapy for bipolar disorder and alcohol misuse with promising results in terms of the feasibility of delivering the therapy and the acceptability to participants. Aims: Here we present the experiences of the therapists and supervisors from the trial to identify the key challenges in working with this client group and how these might be overcome. Method: Four therapists and two supervisors participated in a focus group. Topic guides for the group were informed by a summary of challenges and obstacles that each therapist had completed at the end of therapy for each individual client. The audio recording of the focus group was transcribed and data were analysed using thematic analysis.Results:We identified five themes: addressing alcohol use versus other problems; impact of bipolar disorder on therapy; importance of avoidance and overcoming it; fine balance in relation to shame and normalising use; and 'talking the talk' versus 'walking the walk'. Conclusions: Findings suggest that clients may be willing to explore motivations for using alcohol even if they are not ready to change their drinking, and they may want help with a range of mental health problems. Emotional and behavioural avoidance may be a key factor in maintaining alcohol use in this client group and therapists should be aware of a possible discrepancy between clients' intentions to reduce misuse and their actual behaviour

Towards understanding the variability in biospheric CO2 fluxes:Using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO2

Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world