380 research outputs found
Generation of Arbitrary Frequency Chirps with a Fiber-Based Phase Modulator and Self-Injection-Locked Diode Laser
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
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
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
Mindfulness-based stress reduction and health-related quality of life in a heterogeneous patient population
This study examined the effects of mindfulness-based stress reduction (MBSR) on health-related quality of life and physical and psychological symptomatology in a heterogeneous patient population. Patients (n=136) participated in an 8-week MBSR program and were required to practice 20 min of meditation daily. Pre- and post-intervention data were collected by using the Short-Form Health Survey (SF-36), Medical Symptom Checklist (MSCL) and Symptom Checklist-90 Revised (SCL-90-R). Health-related quality of life was enhanced as demonstrated by improvement on all indices of the SF-36, including vitality, bodily pain, role limitations caused by physical health, and social functioning (all P\u3c.01). Alleviation of physical symptoms was revealed by a 28% reduction on the MSCL (P\u3c.0001). Decreased psychological distress was indicated on the SCL-90-R by a 38% reduction on the Global Severity Index, a 44% reduction on the anxiety subscale, and a 34% reduction on the depression subscale (all P\u3c.0001). One-year follow-up revealed maintenance of initial improvements on several outcome parameters. We conclude that a group mindfulness meditation training program can enhance functional status and well-being and reduce physical symptoms and psychological distress in a heterogeneous patient population and that the intervention may have long-term beneficial effects
Mindfulness-based stress reduction lowers psychological distress in medical students
Background: Medical students confront significant academic, psychosocial, and existential stressors throughout their training. Mindfulness-based stress reduction (MBSR) is an educational intervention designed to improve coping skills and reduce emotional distress.
Purpose: The purpose of this study was to examine the effectiveness of the MBSR intervention in a prospective, nonrandomized, cohort-controlled study.
Methods: Second-year students (n = 140) elected to participate in a 10-week MBSR seminar. Controls (n = 162) participated in a didactic seminar on complementary medicine. Profile of Mood States (POMS) was administered preintervention and postintervention.
Results: Baseline total mood disturbance (TMD) was greater in the MBSR group compared with controls (38.7 ± 33.3 vs. 28.0 ± 31.2; p \u3c .01). Despite this initial difference, the MBSR group scored significantly lower in TMD at the completion of the intervention period (31.8 ± 33.8 vs. 38.6 ± 32.8; p \u3c .05). Significant effects were also observed on Tension–Anxiety, Confusion–Bewilderment, Fatigue–Inertia, and Vigor–Activity subscales.
Conclusion: MBSR may be an effective stress management intervention for medical students
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Evaluation of [11C]metergoline as a PET Radiotracer for 5HTR in Nonhuman Primates
Metergoline, a serotonin receptor antagonist, was labeled with carbon-11 in order to evaluate its pharmacokinetics and distribution in non-human primates using positron emission tomography. [11C]Metergoline had moderate brain uptake and exhibited heterogeneous specific binding, which was blocked by pretreatment with metergoline and altanserin throughout the cortex. Non-specific binding and insensitivity to changes in synaptic serotonin limit its potential as a PET radiotracer. However, the characterization of [11C]metergoline pharmacokinetics and binding in the brain and peripheral organs using PET improves our understanding of metergoline drug pharmacology.Chemistry and Chemical Biolog
The Effectiveness of the Learning to BREATHE Program on Adolescent Emotion Regulation
This study assessed the effectiveness of a mindfulness-based program, Learning to BREATHE, on adolescent emotion regulation. Participants included 216 regular education public high school students with pretest and posttest data participating in the program or instruction-as-usual comparison condition. Program participants reported statistically lower levels of perceived stress and psychosomatic complaints and higher levels of efficacy in affective regulation. Program participants also evidenced statistically larger gains in emotion regulation skills including emotional awareness, access to regulation strategies, and emotional clarity. These findings provide promising evidence of the effectiveness of Learning to BREATHE on the development of key social-emotional learning skills
Wongi mi bardup (doing it our way)
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
Introduction of highly resistant bacteria into a hospital via patients repatriated or recently hospitalized in a foreign country
AbstractWe describe the prevalence of carriage and variables associated with introduction of highly drug-resistant microorganisms (HDRMO) into a French hospital via patients repatriated or recently hospitalized in a foreign country. The prevalence of HDRMO was 11% (15/132), with nine carbapenamase-producing Enterobacteriaceae, nine carbapenem-resistant Acinetobacter baumannii and six glycopeptide-resistant enterococci. Half of the admitted patients (63/132, 48%) were colonized with extended spectrum beta-lactamase-producing Enterobacteriaceae (ESBLPE). Among the four episodes with secondary cases, three involved A. baumannii
An adapted mindfulness-based stress reduction program for elders in a continuing care retirement community: quantitative and qualitative results from a pilot randomized controlled trial.
The purpose of this study was to test the feasibility and effectiveness of an adapted 8-week Mindfulness-Based Stress Reduction (MBSR) program for elders in a continuing care community. This mixed-methods study used both quantitative and qualitative measures. A randomized waitlist control design was used for the quantitative aspect of the study. Thirty-nine elderly were randomized to MBSR (n = 20) or a waitlist control group (n = 19), mean age was 82 years. Both groups completed pre-post measures of health-related quality of life, acceptance and psychological flexibility, facets of mindfulness, self-compassion, and psychological distress. A subset of MBSR participants completed qualitative interviews. MBSR participants showed significantly greater improvement in acceptance and psychological flexibility and in role limitations due to physical health. In the qualitative interviews, MBSR participants reported increased awareness, less judgment, and greater self-compassion. Study results demonstrate the feasibility and potential effectiveness of an adapted MBSR program in promoting mind-body health for elders
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