Four-photon correction in two-photon Bell experiments

Correlated photons produced by spontaneous parametric down-conversion are an essential tool for quantum communication, especially suited for long-distance connections. To have a reasonable count rate after all the losses in the propagation and the filters needed to improve the coherence, it is convenient to increase the intensity of the laser that pumps the non-linear crystal. By doing so, however, the importance of the four-photon component of the down-converted field increases, thus degrading the quality of two-photon interferences. In this paper, we present an easy derivation of this nuisance valid for any form of entanglement generated by down-conversion, followed by a full study of the problem for time-bin entanglement. We find that the visibility of two-photon interferences decreases as V=1-2\rho, where \rho is, in usual situations, the probability per pulse of creating a detectable photon pair. In particular, the decrease of V is independent of the coherence of the four-photon term. Thanks to the fact that \rho can be measured independently of V, the experimental verification of our prediction is provided for two different configuration of filters.Comment: 16 pages, 4 figures; published versio

Middle leading in Australian schools: professional standards, positions, and professional development

In Australia, there is a national education agenda for school improvement with an increasing focus on how school leaders can fulfil this agenda. As school principals are arguably faced with increasing demands, the importance of school middle leaders is increasing. This article presents the initial findings from a larger project on middle leadership in Australian schools, the first phase of which is a documentary analysis of significant texts including policy documents, websites and reports. The purpose of the document analysis was to examine expectations placed on, and support provided for, school middle leaders in Australian schools to make explicit the potential implications for policymakers, leaders and researchers investigating this field. We argue there is a lack of clarity about the role of middle leadership across Australia, with unclear policies, and variations in expectations, titles and levels of support. What is evident is that middle leaders play a pivotal role as they lead teaching, learning, and pastoral care. They carry out these roles in subject areas, key stages and classrooms, and among teachers. While there are a range of professional development provisions for middle leaders across different states, middle leadership needs to be an area of increased focus across Australia

Experimental verification of energy correlations in entangled photon pairs

Properties of entangled photon pairs generated in spontaneous parametric down-conversion are investigated in interference experiments. Strong energy correlations are demonstrated in a direct way. If a signal photon is detected behind a narrow spectral filter, then interference appears in the Mach-Zehnder interferometer placed in the route of the idler photon, even if the path difference in the interferometer exceeds the coherence length of the light. Narrow time correlations of the detection instants are demonstrated for the same photon-pair source using the Hong-Ou-Mandel interferometer. Both these two effects may be exhibited only by an entangled state.Comment: 8 pages, 7 figure

What Should a Psychiatrist Know About Genetics? Review and Recommendations From the Residency Education Committee of the International Society of Psychiatric Genetics.

The International Society of Psychiatric Genetics (ISPG) created a Residency Education Committee with the purpose of identifying key genetic knowledge that should be taught in psychiatric training programs. Thirteen committee members were appointed by the ISPG Board of Directors, based on varied training, expertise, gender, and national origin. The Committee has met quarterly for the past 2 years, with periodic reports to the Board and to the members of the Society. The information summarized includes the existing literature in the field of psychiatric genetics and the output of ongoing large genomics consortia. An outline of clinically relevant areas of genetic knowledge was developed, circulated, and approved. This document was expanded and annotated with appropriate references, and the manuscript was developed. Specific information regarding the contribution of common and rare genetic variants to major psychiatric disorders and treatment response is now available. Current challenges include the following: (1) Genetic testing is recommended in the evaluation of autism and intellectual disability, but its use is limited in current clinical practice. (2) Commercial pharmacogenomic testing is widely available, but its utility has not yet been clearly established. (3) Other methods, such as whole exome and whole genome sequencing, will soon be clinically applicable. The need for informed genetic counseling in psychiatry is greater than ever before, knowledge in the field is rapidly growing, and genetic education should become an integral part of psychiatric training

Bright filter-free source of indistinguishable photon pairs

We demonstrate a high-brightness source of pairs of indistinguishable photons based on a type-II phase-matched doubly-resonant optical parametric oscillator operated far below threshold. The cavity-enhanced down-conversion output of a PPKTP crystal is coupled into two single-mode fibers with a mode coupling efficiency of 58%. The high degree of indistinguishability between the photons of a pair is demonstrated by a Hong-Ou-Mandel interference visibility of higher than 90% without any filtering at an instantaneous coincidence rate of 450 000 pairs/s per mW of pump power per nm of down-conversion bandwidth. For the degenerate spectral mode with a linewidth of 7 MHz at 795 nm a rate of 70 pairs/(s mW MHz) is estimated, increasing the spectral brightness for indistinguishable photons by two orders of magnitude compared to similar previous sources.Comment: 7 pages, 3 figure

Individual differences in vicarious pain perception linked to heightened socially elicited emotional states

For some people (vicarious pain responders), seeing others in pain is experienced as pain felt on their own body and this has been linked to differences in the neurocognitive mechanisms that support empathy. Given that empathy is not a unitary construct, the aim of this study was to establish which empathic traits are more pronounced in vicarious pain responders. The Vicarious Pain Questionnaire (VPQ) was used to divide participants into three groups: (1) non-responders (people who report no pain when seeing someone else experiencing physical pain), (2) sensory-localized responders (report sensory qualities and a localized feeling of pain) and (3) affective-general responders (report a generalized and emotional feeling of pain). Participants completed a series of questionnaires including the Interpersonal Reactivity Index (IRI), the Empathy Quotient (EQ), the Helping Attitudes Scale (HAS), and the Emotional Contagion Scale (ECS) as well as The Individualism - Collectivism Interpersonal Assessment Inventory (ICIAI) and a self-other association task. Both groups of vicarious pain responders showed significantly greater emotional contagion and reactivity, but there was no evidence for differences in other empathic traits or self-other associations. Subsequently, the variables were grouped by a factor analysis and three main latent variables were identified. Vicarious pain responders showed greater socially elicited emotional states which included the ECS, the Emotional Reactivity Subscale of EQ and the HAS. These results show that consciously feeling the physical pain of another is mainly linked to heightened emotional contagion and reactivity which together with the HAS loaded on the socially elicited emotional states factor indicating that, in our population, these differences lead to a more helpful rather than avoidant behavior

Bell State Preparation using Pulsed Non-Degenerate Two-Photon Entanglement

We report a novel Bell state preparation experiment. High-purity Bell states are prepared by using femtosecond pulse pumped \emph{nondegenerate} collinear spontaneous parametric down-conversion. The use of femtosecond pump pulse {\em does not} result in reduction of quantum interference visibility in our scheme in which post-selection of amplitudes and other traditional mechanisms, such as, using thin nonlinear crystals or narrow-band spectral filters are not used. Another distinct feature of this scheme is that the pump, the signal, and the idler wavelengths are all distinguishable, which is very useful for quantum communications.Comment: 4 pages, submitted to PR

Involucrin modulates vitamin D receptor activity in the epidermis

Terminally differentiated keratinocytes are critical for epidermal function and are surrounded by involucrin (IVL). Increased IVL expression is associated with a near-selective sweep in European populations compared with those in Africa. This positive selection for increased IVL in the epidermis identifies human adaptation outside of Africa. The functional significance is unclear. We hypothesize that IVL modulates the environmentally sensitive vitamin D receptor (VDR) in the epidermis. We investigated VDR activity in Iv

The intersection between Descriptivism and Meliorism in reasoning research: further proposals in support of 'soft normativism'

The rationality paradox centres on the observation that people are highly intelligent, yet show evidence of errors and biases in their thinking when measured against normative standards. Elqayam and Evans (e.g., 2011) reject normative standards in the psychological study of thinking, reasoning and deciding in favour of a ‘value-free’ descriptive approach to studying high-level cognition. In reviewing Elqayam and Evans’ position, we defend an alternative to descriptivism in the form of ‘soft normativism’, which allows for normative evaluations alongside the pursuit of descriptive research goals. We propose that normative theories have considerable value provided that researchers: (1) are alert to the philosophical quagmire of strong relativism; (2) are mindful of the biases that can arise from utilising normative benchmarks; and (3) engage in a focused analysis of the processing approach adopted by individual reasoners. We address the controversial ‘is–ought’ inference in this context and appeal to a ‘bridging solution’ to this contested inference that is based on the concept of ‘informal reflective equilibrium’. Furthermore, we draw on Elqayam and Evans’ recognition of a role for normative benchmarks in research programmes that are devised to enhance reasoning performance and we argue that such Meliorist research programmes have a valuable reciprocal relationship with descriptivist accounts of reasoning. In sum, we believe that descriptions of reasoning processes are fundamentally enriched by evaluations of reasoning quality, and argue that if such standards are discarded altogether then our explanations and descriptions of reasoning processes are severely undermined

Mapeamento e avaliação ecológica de Áreas de Preservação Permanente do rio Catu, Alagoinhas, Bahia, Brasil

The Catu river micro-basin is part of the North Reconcavo Hydrographic Basin that has been experiencing degradation due to anthropogenic disturbances during recent decades. To better understand the status of the Catu river, the present study evaluated and mapped the ecological integrity of the vegetation fragments in the Permanent Preservation Area along its banks. We used the Relative Ecological Vulnerability index, the landscape connectivity, the Fluvial Functionality Index and a decision-making key for recovering degraded areas. Our results show that forest fragments along the Catu river are very isolated and more than 50% are highly vulnerable to biodiversity losses. The lowest level of fluvial functionality was found in urban areas and the highest in a remnant forest area within the city of Alagoinhas. In addition to the implementation of key actions for the recovery of the areas diagnosed, higher enforcement of environmental laws will be required, as well as urban planning reviews.A microbacia do rio Catu é parte da Bacia Hidrográfica do Recôncavo Norte e vem sendo degradada pela ação antrópica há décadas. Para conhecer melhor a situação do rio Catu, este trabalho avaliou e mapeou a integridade ecológica de fragmentos de vegetação na Área de Preservação Permanente ao longo do seu curso. Nós usamos o índice de Vulnerabilidade Ecológica Relativa, a conectividade da paisagem, o Índice de Funcionalidade Fluvial e uma chave para tomada de decisões na recuperação de áreas degradadas. Nossos resultados mostram que os fragmentos florestais ao longo do rio Catu estão bastante isolados e mais de 50% encontram-se altamente vulneráveis à perda de biodiversidade. O menor nível de funcionalidade fluvial foi encontrado na área urbana e o maior em um remanescente florestal na cidade de Alagoinhas. Além da execução das principais ações para recuperação das áreas diagnosticadas, é necessária maior fiscalização do cumprimento das leis ambientais e uma revisão do planejamento urbano