431 research outputs found

    The Hymn That Touched My Heart

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    https://digitalcommons.library.umaine.edu/mmb-vp/5287/thumbnail.jp

    Generation of Arbitrary Frequency Chirps with a Fiber-Based Phase Modulator and Self-Injection-Locked Diode Laser

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    We present a novel technique for producing pulses of laser light whose frequency is arbitrarily chirped. The output from a diode laser is sent through a fiber-optical delay line containing a fiber-based electro-optical phase modulator. Upon emerging from the fiber, the phase-modulated pulse is used to injection-lock the laser and the process is repeated. Large phase modulations are realized by multiple passes through the loop while the high optical power is maintained by self-injection-locking after each pass. Arbitrary chirps are produced by driving the modulator with an arbitrary waveform generator

    The Conserved nhaAR Operon Is Drastically Divergent between B2 and Non-B2 Escherichia coli and Is Involved in Extra-Intestinal Virulence

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    The Escherichia coli species is divided in phylogenetic groups that differ in their virulence and commensal distribution. Strains belonging to the B2 group are involved in extra-intestinal pathologies but also appear to be more prevalent as commensals among human occidental populations. To investigate the genetic specificities of B2 sub-group, we used 128 sequenced genomes and identified genes of the core genome that showed marked difference between B2 and non-B2 genomes. We focused on the gene and its surrounding region with the strongest divergence between B2 and non-B2, the antiporter gene nhaA. This gene is part of the nhaAR operon, which is in the core genome but flanked by mobile regions, and is involved in growth at high pH and high sodium concentrations. Consistently, we found that a panel of non-B2 strains grew faster than B2 at high pH and high sodium concentrations. However, we could not identify differences in expression of the nhaAR operon using fluorescence reporter plasmids. Furthermore, the operon deletion had no differential impact between B2 and non-B2 strains, and did not result in a fitness modification in a murine model of gut colonization. Nevertheless, sequence analysis and experiments in a murine model of septicemia revealed that recombination in nhaA among B2 strains was observed in strains with low virulence. Finally, nhaA and nhaAR operon deletions drastically decreased virulence in one B2 strain. This effect of nhaAR deletion appeared to be stronger than deletion of all pathogenicity islands. Thus, a population genetic approach allowed us to identify an operon in the core genome without strong effect in commensalism but with an important role in extra-intestinal virulence, a landmark of the B2 strains

    Broadband Optical Serrodyne Frequency Shifting

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    We demonstrate serrodyne frequency shifting of light from 200 MHz to 1.2 GHz with an efficiency of better than 60 percent. The frequency shift is imparted by an electro-optic phase modulator driven by a high-frequency, high-fidelity sawtooth waveform that is passively generated by a commercially available Non-Linear Transmission Line (NLTL). We also implement a push-pull configuration using two serrodyne-driven phase modulators allowing for continuous tuning between -1.6 GHz and +1.6 GHz. Compared to competing technologies, this technique is simple and robust, and offers the largest available tuning range in this frequency band.Comment: 3 pages, 4 figure

    Wongi mi bardup (doing it our way)

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    The Birthing on Noongar Boodjar project investigated the cultural birthing practices of Aboriginal women living on country (Noongar Boodjar) in an urbanised environment; and their experiences of interactions with maternal health care providers (especially midwives). The evidence from the five year study identified changes required in health systems to adequately support Aboriginal women and their families during the significant cultural and life event of childbearing. This paper sets out the methodological and theoretical considerations which framed how the Birthing on Noongar Boodjar project was conducted by the Aboriginal and non-Aboriginal investigators. We provide a brief project background before describing the Indigenous research methodologies and practices crucial to exploring the research questions, collecting data in culturally secure ways and using cultural lenses to analyze and interpret the data. The study design and results are reported in other publications

    Fermilab E791

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    Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

    A pilot randomised controlled trial investigating a mindfulness-based stress reduction (MBSR) intervention in individuals with pulmonary arterial hypertension (PAH): the PATHWAYS study

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    Background: Pulmonary arterial hypertension (PAH) is an uncommon condition with progressive heart failure and premature death. Treatment costs up to £120,000 per patient per year, and the psychological burden of PAH is substantial. Mindfulness-based stress reduction (MBSR) is an intervention with the potential to reduce this burden, but to date, it has not been applied to people with pulmonary hypertension. We wished to determine whether a trial of MBSR for people with PAH would be feasible. Methods: A customised gentle MBSR programme of eight sessions was developed for people with physical disability due to PAH, and they were randomised to group-based MBSR or treatment as usual. The completeness of outcome measures including Beck Anxiety Index, Beck Depression Inventory and standard physical assessment at 3 months after randomisation were recorded. Health care utilisation was measured. Attendance at the sessions and the costs involved in delivering the intervention were assessed. Semi-structured interviews were conducted to explore the acceptability of the MBSR intervention and when appropriate the reasons for trial non-participation. Results: Fifty-two patients were recruited, but only 34 were randomised due to patients finding it difficult to travel to sessions. Twenty-two completed all questionnaires and attended all clinics, both routine and additional in order to collect outcomes measures. The MSBR sessions were delivered in Bristol, Cardiff and London, costing, on average, between £2234 (Cardiff) and £4128 (London) per patient to deliver. Attendance at each session averaged between two patients in Bristol and Cardiff and three in London. For those receiving treatment as usual, clinician blinding was achievable. Interviews revealed that people who attended MBSR found it interesting and helpful in managing their symptoms and minimising the psychological component of their disease. Conclusions: We found that attendance at group MBSR was poor in people with chronic PAH within the context of a trial. Achieving better MBSR intervention attendance or use of an Internet-based programme might maximise the benefit of MBSR

    Rev-erbα in the brain is essential for circadian food entrainment.

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    Foraging is costly in terms of time and energy. An endogenous food-entrainable system allows anticipation of predictable changes of food resources in nature. Yet the molecular mechanism that controls food anticipation in mammals remains elusive. Here we report that deletion of the clock component Rev-erbα impairs food entrainment in mice. Rev-erbα global knockout (GKO) mice subjected to restricted feeding showed reduced elevations of locomotor activity and body temperature prior to mealtime, regardless of the lighting conditions. The failure to properly anticipate food arrival was accompanied by a lack of phase-adjustment to mealtime of the clock protein PERIOD2 in the cerebellum, and by diminished expression of phosphorylated ERK 1/2 (p-ERK) during mealtime in the mediobasal hypothalamus and cerebellum. Furthermore, brain-specific knockout (BKO) mice for Rev-erbα display a defective suprachiasmatic clock, as evidenced by blunted daily activity under a light-dark cycle, altered free-running rhythm in constant darkness and impaired clock gene expression. Notably, brain deletion of Rev-erbα totally prevented food-anticipatory behaviour and thermogenesis. In response to restricted feeding, brain deletion of Rev-erbα impaired changes in clock gene expression in the hippocampus and cerebellum, but not in the liver. Our findings indicate that Rev-erbα is required for neural network-based prediction of food availability.journal article2016 Jul 062016 07 06importe
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