Light bullets in Bessel optical lattices with spatially modulated nonlinearity

We address the stability of light bullets supported by Bessel optical lattices with out-of-phase modulation of the linear and nonlinear refractive indices. We show that spatial modulation of the nonlinearity significantly modifies the shapes and stability domains of the light bullets. The addressed bullets can be stable, provided that the peak intensity does not exceed a critical value. We show that the width of the stability domain in terms of the propagation constant may be controlled by varying the nonlinearity modulation depth. In particular, we show that the maximum energy of the stable bullets grows with increasing nonlinearity modulation depth.Peer ReviewedPostprint (published version

Growth hormone secretagogues exert differential effects on skeletal muscle calcium homeostasis in male rats depending on the peptidyl/non-peptidyl structure

TheorexigenicandanaboliceffectsinducedbyghrelinandthesyntheticGHsecretagogues(GHSs) are thought to positively contribute to therapeutic approaches and the adjunct treatment of a number of diseases associated with muscle wasting such as cachexia and sarcopenia. However, manyquestionsaboutthepotentialutilityandsafetyofGHSsinboththerapyandskeletalmuscle functionremainunanswered.Byusingfura-2cytofluorimetrictechnique,wedeterminedtheacute effectsofghrelin,aswellasofpeptidylandnonpeptidylsyntheticGHSsoncalciumhomeostasis, a critical biomarker of muscle function, in isolated tendon-to-tendon male rat skeletal muscle fibers.ThesyntheticnonpeptidylGHSs,butnotpeptidylghrelinandhexarelin,wereabletosignificantlyincreaserestingcytosoliccalcium[Ca2]i.ThenonpeptidylGHS-induced[Ca2] iincrease was independent of GHS-receptor 1a but was antagonized by both thapsigargin/caffeine and cyclosporineA,indicatingtheinvolvementofthesarcoplasmicreticulumandmitochondria.EvaluationoftheeffectsofapseudopeptidylGHSandanonpeptidylantagonistoftheGHS-receptor 1a together with a drug-modeling study suggest the conclusion that the lipophilic nonpeptidyl structureofthetestedcompoundsisthekeychemicalfeaturecrucialfortheGHS-inducedcalcium alterationsintheskeletalmuscle.Thus,syntheticGHSscanhavedifferenteffectsonskeletalmuscle fibersdependingontheirmolecularstructures.Thecalciumhomeostasisdysregulationspecifically induced by the nonpeptidyl GHSs used in this study could potentially counteract the beneficial effects associated with these drugs in the treatment of muscle wasting of cachexia- or other age-related disorders

Black hole entropy in 3D gravity with torsion

The role of torsion in quantum three-dimensional gravity is investigated by studying the partition function of the Euclidean theory in Riemann-Cartan spacetime. The entropy of the black hole with torsion is found to differ from the standard Bekenstein-Hawking result, but its form is in complete agreement with the first law of black hole thermodynamics.Comment: 17 pages, RevTeX, minor revision

Does hypoglycemia following a glucose challenge test identify a high risk pregnancy?

<p>Abstract</p> <p>Objective</p> <p>An association between maternal hypoglycemia during pregnancy with fetal growth restriction and overall perinatal mortality has been reported. In a retrospective pilot study we found that hypoglycemia was linked with a greater number of special care/neonatal intensive care unit admissions and approached significance in the number of women who developed preeclampsia. That study was limited by its retrospective design, a narrow patient population and the inability to perform multivariate analysis because of the limitations in the data points collected. This study was undertaken to compare the perinatal outcome in pregnancies with hyoglycemia following a glucose challenge test (GCT) to pregnancies with a normal GCT.</p> <p>Methods</p> <p>Obstetric patients (not pre-gestational diabetics or gestational diabetes before 24 weeks were eligible. Women with a 1 hour glucose ≤ 88 mg/dL (4.8 m/mol) following a 50-gram oral GCT were matched with the next patient with a 1 hour glucose of 89–139 mg/dL. Pregnancy outcomes were evaluated.</p> <p>Results</p> <p>Over 22 months, 436 hypoglycemic patients and 434 normal subjects were identified. Hypoglycemia was increased in women < 25 (p = 0.003) and with pre-existing medical conditions (p < 0.001). Hypoglycemia was decreased if pre-pregnancy BMI ≥ 30 (p = 0.008).</p> <p>Preeclampsia/eclampsia was more common in hypoglycemic women. (OR = 3.13, 95% CI 1.51 – 6.51, p = 0.002) but not other intrapartum and perinatal outcomes.</p> <p>Conclusion</p> <p>Hypoglycemic patients are younger, have reduced pre-pregnancy weight, lower BMIs, and are more likely to develop preeclampsia than normoglycemic women.</p

Preventing Falls in Older Californians: State of the Art

In February 2003, the Foundation convened over 150 leaders in academic, legislative, community-based services, consumer advocates, aging network, housing, public health, public safety, and other leaders who worked for two days on a statewide blueprint on fall prevention.  In preparation for the convening, a Preconference White Paper was created and used to build the blueprint.  The California Blueprint describes state-of-the-art approaches to reducing the risks of falls, and the challenges to implementing fall prevention in California.  One of the top recommendations from this blueprint was the creation of a coordination center that could serve as a statewide resource and lead efforts in fall prevention.  This recommendation eventually led to the creation of the Fall Prevention Center of Excellence (FPCE)

Observation of Pulsed Gamma-rays Above 25 GeV from the Crab Pulsar with MAGIC

One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we lowered the threshold of the Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 GeV. In this configuration, we detected pulsed gamma-rays from the Crab pulsar that were greater than 25 GeV, revealing a relatively high cutoff energy in the phase-averaged spectrum. This indicates that the emission occurs far out in the magnetosphere, hence excluding the polar-cap scenario as a possible explanation of our measurement. The high cutoff energy also challenges the slot-gap scenario.Comment: Slight modification of the analysis: Fitting a more general function to the combined data set of COMPTEL, EGRET and MAGIC. Final result and conclusion is unchange

First bounds on the high-energy emission from isolated Wolf-Rayet binary systems

High-energy gamma-ray emission is theoretically expected to arise in tight binary star systems (with high mass loss and high velocity winds), although the evidence of this relationship has proven to be elusive so far. Here we present the first bounds on this putative emission from isolated Wolf-Rayet (WR) star binaries, WR 147 and WR 146, obtained from observations with the MAGIC telescope.Comment: (Authors are the MAGIC Collaboration.) Manuscript in press at The Astrophysical Journal Letter