2,242 research outputs found

    Spatial and temporal patterns of Pseudo-nitzschia genetic diversity in the North Pacific Ocean from the Continuous Plankton Recorder survey

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    Several species of the marine diatom Pseudo-nitzschia can produce the neurotoxin domoic acid that is responsible for the seafood-borne illness amnesic shellfish poisoning in humans, marine wildlife mortalities and prolonged closures of fisheries resulting in economic losses to coastal communities. Since the year 2000, Pseudo-nitzschia species have been monitored in the Pacific Ocean with the Continuous Plankton Recorder (CPR). We used a combination of scanning electron microscopy with high-throughput and Sanger sequencing of CPR survey samples to compare the diversity of phytoplankton, including Pseudo-nitzschia species, from the north-eastern Pacific Ocean over 3 climatically different years: 2002, 2005 and 2008. A Pseudo-nitzschia-specific primer set targeting a partial region of the large subunit ribosomal DNA (rDNA) revealed spatially separated communities of Pseudo-nitzschia. The coastal region was dominated by a diverse array of P. fraudulenta unique sequences (operational taxonomic units), whereas the offshore region was rich in P. multiseries and contained a wide range of other Pseudo-nitzschia taxa, many not previously observed in this region. In 2008, exceptionally cold sea surface temperatures were recorded, influenced by a strong negative Pacific Decadal Oscillation signal. In that year, a more diverse assemblage of species was present in a spring open water sample, whereas P. fraudulenta was unusually rare from a coastal autumn sample. This is the first application of high-throughput genetic methods to uncover patterns of Pseudo-nitzschia genetic diversity from archival CPR samples, demonstrating the value of using CPR for plankton community analysis in rarely sampled regions of the oceans

    Do red deer stags (Cervus elaphus) use roar fundamental frequency (F0) to assess rivals?

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    It is well established that in humans, male voices are disproportionately lower pitched than female voices, and recent studies suggest that this dimorphism in fundamental frequency (F0) results from both intrasexual (male competition) and intersexual (female mate choice) selection for lower pitched voices in men. However, comparative investigations indicate that sexual dimorphism in F0 is not universal in terrestrial mammals. In the highly polygynous and sexually dimorphic Scottish red deer Cervus elaphus scoticus, more successful males give sexually-selected calls (roars) with higher minimum F0s, suggesting that high, rather than low F0s advertise quality in this subspecies. While playback experiments demonstrated that oestrous females prefer higher pitched roars, the potential role of roar F0 in male competition remains untested. Here we examined the response of rutting red deer stags to playbacks of re-synthesized male roars with different median F0s. Our results show that stags’ responses (latencies and durations of attention, vocal and approach responses) were not affected by the F0 of the roar. This suggests that intrasexual selection is unlikely to strongly influence the evolution of roar F0 in Scottish red deer stags, and illustrates how the F0 of terrestrial mammal vocal sexual signals may be subject to different selection pressures across species. Further investigations on species characterized by different F0 profiles are needed to provide a comparative background for evolutionary interpretations of sex differences in mammalian vocalizations

    Enduring community value from mining: measuring the employment impacts of mine closure for remote communities and considering issues for transformation

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    Tracking and mapping the employment impacts from mine closure forms an important element in planning for the economic transformation of remote communities and delivering enduring value from mining. This paper presents the results from two case studies of the employment impacts from mine closure: 1) the Ranger uranium mine in the Northern Territory and 2) the Leigh Creek coal mine in South Australia. The impacts for both locations are significant and link to a number of supporting industries, particularly construction, but also more broadly across other sectors of the economy. The spatial impacts are principally felt locally, but are also distributed more broadly at regional, state and national scales because of modern-day work commuting practices. Loss of jobs and associated income to Aboriginal and Torres Strait Islander people are also significant. Developing policy options to prepare for managing imminent mine closures in remote locations requires careful analysis of the structure of the local economy, within the context of a globalised world, in order to help identify sustainable transformation opportunities for these remote communities

    Mentoring programs for medical students - a review of the PubMed literature 2000 - 2008

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    Abstract Background Although mentoring is acknowledged as a key to successful and satisfying careers in medicine, formal mentoring programs for medical students are lacking in most countries. Within the framework of planning a mentoring program for medical students at Zurich University, an investigation was carried out into what types of programs exist, what the objectives pursued by such programs are, and what effects are reported. Methods A PubMed literature search was conducted for 2000 - 2008 using the following keywords or their combinations: mentoring, mentoring program, medical student, mentor, mentee, protégé, mentorship. Although a total of 438 publications were identified, only 25 papers met the selection criteria for structured programs and student mentoring surveys. Results The mentoring programs reported in 14 papers aim to provide career counseling, develop professionalism, increase students' interest in research, and support them in their personal growth. There are both one-to-one and group mentorships, established in the first two years of medical school and continuing through graduation. The personal student-faculty relationship is important in that it helps students to feel that they are benefiting from individual advice and encourages them to give more thought to their career choices. Other benefits are an increase in research productivity and improved medical school performance in general. Mentored students also rate their overall well-being as higher. - The 11 surveys address the requirements for being an effective mentor as well as a successful mentee. A mentor should empower and encourage the mentee, be a role model, build a professional network, and assist in the mentee's personal development. A mentee should set agendas, follow through, accept criticism, and be able to assess performance and the benefits derived from the mentoring relationship. Conclusion Mentoring is obviously an important career advancement tool for medical students. In Europe, more mentoring programs should be developed, but would need to be rigorously assessed based on evidence of their value in terms of both their impact on the career paths of juniors and their benefit for the mentors. Medical schools could then be monitored with respect to the provision of mentorships as a quality characteristic.</p

    Plasma and Muscle Myostatin in Relation to Type 2 Diabetes

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    OBJECTIVE: Myostatin is a secreted growth factor expressed in skeletal muscle tissue, which negatively regulates skeletal muscle mass. Recent animal studies suggest a role for myostatin in insulin resistance. We evaluated the possible metabolic role of myostatin in patients with type 2 diabetes and healthy controls. DESIGN: 76 patients with type 2 diabetes and 92 control subjects were included in the study. They were matched for age, gender and BMI. Plasma samples and biopsies from the vastus lateralis muscle were obtained to assess plasma myostatin and expression of myostatin in skeletal muscle. RESULTS: Patients with type 2 diabetes had higher fasting glucose (8.9 versus 5.1 mmol/L, P<0.001), plasma insulin (68.2 versus 47.2 pmol/L, P<0.002) and HOMA2-IR (1.6 versus 0.9, P<0.0001) when compared to controls. Patients with type 2 diabetes had 1.4 (P<0.01) higher levels of muscle myostatin mRNA content than the control subjects. Plasma myostatin concentrations did not differ between patients with type 2 diabetes and controls. In healthy controls, muscle myostatin mRNA correlated with HOMA2-IR (r = 0.30, P<0.01), plasma IL-6 (r = 0.34, P<0.05) and VO2 max (r = -0.26, P<0.05), however, no correlations were observed in patients with type 2 diabetes. CONCLUSIONS: This study supports the idea that myostatin may have a negative effect on metabolism. However, the metabolic effect of myostatin appears to be overruled by other factors in patients with type 2 diabetes

    International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy

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    Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered

    LED Arrays as Cost Effective and Efficient Light Sources for Widefield Microscopy

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    New developments in fluorophores as well as in detection methods have fueled the rapid growth of optical imaging in the life sciences. Commercial widefield microscopes generally use arc lamps, excitation/emission filters and shutters for fluorescence imaging. These components can be expensive, difficult to maintain and preclude stable illumination. Here, we describe methods to construct inexpensive and easy-to-use light sources for optical microscopy using light-emitting diodes (LEDs). We also provide examples of its applicability to biological fluorescence imaging
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