Entanglement between a qubit and the environment in the spin-boson model

The quantitative description of the quantum entanglement between a qubit and its environment is considered. Specifically, for the ground state of the spin-boson model, the entropy of entanglement of the spin is calculated as a function of α, the strength of the ohmic coupling to the environment, and ɛ, the level asymmetry. This is done by a numerical renormalization group treatment of the related anisotropic Kondo model. For ɛ=0, the entanglement increases monotonically with α, until it becomes maximal for α→1-. For fixed ɛ>0, the entanglement is a maximum as a function of α for a value, α=αM

The potential of virulent Wolbachia to modulate disease transmission by insects

A virulent strain of Wolbachia has recently been identified in Drosophila that drastically reduces adult lifespan. It has been proposed that this phenotype might be introduced into insect disease vector populations to reduce pathogen transmission. Here we model the requirements for spread of such an agent and the associated reduction in disease transmission. First, a simulation of mosquito population age structure was used to describe the age distribution of mosquitoes transmitting dengue virus. Second, given varying levels of cytoplasmic incompatibility and fecundity effect, the maximum possible longevity reduction that would allow Wolbachia to invade was obtained. Finally, the two models were combined to estimate the reduction in disease transmission according to different introduction frequencies. With strong CI and limited effect of fecundity, an introduction of Wolbachia with an initial frequency of 0.4 could result in a 60–80% reduction of transmitting mosquitoes. Greater reductions are possible at higher initial release rates.

Emotional awareness and emotional intelligence in leadership teaching

Recent research has highlighted the importance of emotional awareness and emotional intelligence in organizations, and these topics are attracting increasing attention. In this article, the authors present the results of a preliminary classroom study in which emotion concepts were incorporated into an undergraduate leadership course. In the study, students completed self report and ability tests of emotional intelligence. The test results were compared with students' interest in emotions and their performance in the course assessment. Results showed that interest in and knowledge of emotional intelligence predicted team performance, whereas individual performance was related to emotional intelligence.

Myb-binding Protein 1a is a Nucleocytoplasmic Shuttling Protein that Utilizes CRM1-dependent and Independent Nuclear Export Pathways

Myb-binding protein 1a (Mybbp1a) is a novel nuclear protein localized predominantly, but not exclusively, in nucleoli. Although initially isolated as a c-Myb interacting protein, Mybbp1a is expressed ubiquitously, associates with a number of different transcription factors, and may play a role in both RNA polymerase I- and II-mediated transcriptional regulation. However, its precise function remains unclear. In this study we show that Mybbp1a is a nucleocytoplasmic shuttling protein and investigate the mechanisms responsible for both nuclear import and export. The carboxyl terminus of Mybbp1a, which contains seven short basic amino acid repeat sequences, is responsible for both nuclear and nucleolar localization, and this activity can be transferred to a heterologous protein. Deletion mapping demonstrated that these repeat sequences appear to act incrementally, with successive deletions resulting in a corresponding increase in the proportion of protein localized in the cytoplasm. Glutathione S-transferase pulldown experiments showed that the nuclear receptor importin-alpha/beta mediates Mybbp1a nuclear import. Interspecies heterokaryons were used to demonstrate that Mybbp1a was capable of shuttling between the nucleus and the cytoplasm. Deletion analysis and in vivo export studies using a heterologous assay system identified several nuclear export sequences which facilitate Mybbp1a nuclear export of Mybbp1a by CRM1-dependent and -independent pathways. (C) 2003 Elsevier Science (USA). All rights reserved.

Extrinsic versus intrinsic factors in the decline and extinction of Australian marsupials

Recent attempts to explain the susceptibility of vertebrates to declines worldwide have largely focused on intrinsic factors such as body size, reproductive potential, ecological specialization, geographical range and phylogenetic longevity. Here, we use a database of 145 Australian marsupial species to test the effects of both intrinsic and extrinsic factors in a multivariate comparative approach. We model five intrinsic (body size, habitat specialization, diet, reproductive rate and range size) and four extrinsic (climate and range overlap with introduced foxes, sheep and rabbits) factors. We use quantitative measures of geographical range contraction as indices of decline. We also develop a new modelling approach of phylogenetically independent contrasts combined with imputation of missing values to deal simultaneously with phylogenetic structuring and missing data. One extrinsic variable-geographical range overlap with sheep-was the only consistent predictor of declines. Habitat specialization was independently but less consistently associated with declines. This suggests that extrinsic factors largely determine interspecific variation in extinction risk among Australian marsupials, and that the intrinsic factors that are consistently associated with extinction risk in other vertebrates are less important in this group. We conclude that recent anthropogenic changes have been profound enough to affect species on a continent-wide scale, regardless of their intrinsic biology.

Most lymphoid organ dendritic cell types are phenotypically and functionally immature

Dendritic cells (DCs) have been thought to follow a life history, typified by Langerhans cells (LCs), with 2 major developmental stages: an immature stage that captures antigens in the periphery and a mature stage that presents those antigens in the lymphoid organs. However, a systematic assessment of the maturity of lymphoid organ DCs has been lacking. We have analyzed the maturity of the DC types found in the steady state in the spleen, lymph nodes (LNs), and thymus. The DCs that migrate into the iliac, mesenteric, mediastinal, or subcutaneous LNs from peripheral tissues were mature and therefore could not process and present newly encountered antigens. However, all the other DC types were phenotypically and functionally immature: they expressed low levels of surface major histocompatibility complex class 11 (MHC 11) and CD86, accumulated MHC 11 in their endosomes, and could present newly encountered antigens. These immature DCs could 1346 induced to mature by culture in vitro or by Inoculation of inflammatory stimuli in vivo. Therefore, the lymphoid organs contain a large cohort of immature DCs, most likely for the maintenance of peripheral tolerance, which can respond to infections reaching those organs and mature in situ. (C) 2003 by The American Society of Hematology.

Low symbiont diversity in southern Great Barrier Reef corals, relative to those of the Caribbean

The specific identity of endosymbiotic dinoflagellates (Symbiodinium spp.) from most zooxanthellate corals is unknown. In a survey of symbiotic cnidarians from the southern Great Barrier Reef (GBR), 23 symbiont types were identified from 86 host species representing 40 genera. A majority (>85%) of these symbionts belong to a single phylogenetic clade or subgenus (C) composed of closely related (as assessed by sequence data from the internal transcribed spacer region and the ribosomal large subunit gene), yet ecologically and physiologically distinct, types. A few prevalent symbiont types, or generalists, dominate the coral community of the southern GBR, whereas many rare and/or specific symbionts, or specialists, are found uniquely within certain host taxa. The comparison of symbiont diversity between southern GBR and Caribbean reefs shows an inverse relationship between coral diversity and symbiont diversity, perhaps as a consequence of more-rapid diversification of Caribbean symbionts. Among clade C types, generalists C1 and C3 are common to both Caribbean and southern GBR symbiont assemblages, whereas the rest are regionally endemic. Possibly because of environmental changes in the Caribbean after geographic isolation through the Quaternary period, a high proportion of Caribbean fauna associate with symbiont taxa from two other distantly related Symbiodinium clades (A and B) that rarely occur in Pacific hosts. The resilience of Porites spp. and the resistance of Montipora digitata to thermal stress and bleaching are partially explained by their association with a thermally tolerant symbiont type, whereas the indiscriminant widespread bleaching and death among certain Pacific corals, during El Nino Southern Oscillation events, are influenced by associations with symbionts possessing higher sensitivity to thermal stress.

Sodium channel alpha 1-subunit mutations in severe myoclonic epilepsy of infancy and infantile spasms

Background: Mutations in SCN1A, the gene encoding the alpha1 subunit of the sodium channel, have been found in severe myoclonic epilepsy of infancy (SMEI) and generalized epilepsy with febrile seizures plus (GEFS(+)). Mutations in SMEI include missense, nonsense, and frameshift mutations more commonly arising de novo in affected patients. This finding is difficult to reconcile with the family history of GEFS(+) in a significant proportion of patients with SMEI Infantile spasms (IS), or West syndrome, is a severe epileptic encephalopathy that is usually symptomatic. In some cases, no etiology is found and there is a family history of epilepsy. Method: The authors screened SCN1A in 24 patients with SMEI and 23 with IS. Results: Mutations were found in 8 of 24 (33%) SMEI patients, a frequency much lower than initial reports from Europe and Japan. One mutation near the carboxy terminus was identified in an IS patient. A family history of seizures was found in 17 of 24 patients with SMEI. Conclusions: The rate of SCN1A mutations in this cohort of SMEI patients suggests that other factors may be important in SMEI. Less severe mutations associated with GEFS(+) could interact with other loci to cause SMEI in cases with a family history of GEFS(+). This study extends the phenotypic heterogeneity of mutations in SCN1A to include IS.

Palliative care at home: general practitioners working with palliative care teams

Home care is the preferred option for most people with a terminal illness. Providing home care relies on good community-based services, and a general practice workforce competent in palliative care practice and willing to accommodate patients' needs. Structured palliative care training of general practitioners is needed at undergraduate and postgraduate level, with attention to barriers to teamwork and communication. Good palliative care-can be delivered to patients at home by GPs (supported by specialist palliative care teams) and community nurses, with access to an inpatient facility when required. To optimise patient care, careful planning and good communication between all members of the healthcare team is crucial.

Social class and cultural mobility - Reconfiguring the cultural omnivore thesis

This article explores the idea of 'cultural mobility' both as a way of thinking about the polarizing logic of class relations and practices in contemporary society and as a means by which the debate over the cultural omnivore might be advanced. The concept of cultural mobility refers to the differential capacity to engage with or consume cultural goods and services across the entire spectrum of cultural life, an ability which is itself premised upon an unequal, class-related distribution in cultural competence. Cultural mobility, then, is the ability to move at will between cultural realms, a freedom to choose where one is positioned in the cultural landscape. I argue that the concept provides fertile ground for exploring possible interconnections between a number of divergent strands in current social theory which have largely developed independently of each other. At the same time much of this theoretical effort remains divorced from concrete research agendas. Using data collected as part of a major study of Australian cultural consumption, the article provides a case study of cultural mobility and its class moorings which serves to clarify some of the existing confusions concerning the cultural omnivore.

Screening for leprosy in immigrants: A decision analysis model

Almost all leprosy cases reported in industrialized countries occur amongst immigrants or refugees from developing countries where leprosy continues to be an important health issue. Screening for leprosy is an important question for governments in countries with immigration and refugee programmes. A decision analysis framework is used to evaluate leprosy screening. The analysis uses a set of criteria and parameters regarding leprosy screening, and available data to estimate the number of cases which would be detected by a leprosy screening programme of immigrants from countries with different leprosy prevalences, compared with a policy of waiting for immigrants who develop symptomatic clinical diseases to present for health care. In a cohort of 100,000 immigrants from high leprosy prevalence regions (3.6/10,000), screening would detect 32 of the 42 cases which would arise in the destination country over the 14 years after migration; from medium prevalence areas (0.7/10,000) 6.3 of the total 8.1 cases would be detected, and from low prevalence regions (0.2/10,600) 1.8 of 2.3 cases. Using Australian data, the migrant mix would produce 74 leprosy cases from 10 years intake; screening would detect 54, and 19 would be diagnosed subsequently after migration. Screening would only produce significant case-yield amongst immigrants from regions or social groups with high leprosy prevalence. Since the number of immigrants to Australia from countries of higher endemnicity is not large routine leprosy screening would have a small impact on case incidence.

Willingness to pay for different degrees of abundance of elephants

This paper presents an application of the contingent valuation method (CVM) to determine how the willingness to pay (WTP) for conservation of Asian elephants varies with hypothetical variations in their population. Results from a CVM survey of a sample of urban residents in Colombo, the capital of Sri Lanka are used for this purpose. We find, consistent with the basic principles of consumer demand theory, the marginal change in the respondents’ WTP amounts is positive but appears to diminish in parallel to the increases in the current wild elephant population (CWEP). In contrast to theoretical expectations, however, we find that the WTP for preserving this species increases at an increasing rate in relation to decreases in the CWEP. This is probably because respondents perceive that extinction becomes more imminent as the abundance of the elephant is reduced and therefore it becomes more urgent to act. However, this adds a new complication to the interpretation of the WTP findings.