48 research outputs found

    Nonequilibrium Josephson effect in mesoscopic ballistic multiterminal SNS junctions

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    We present a detailed study of nonequilibrium Josephson currents and conductance in ballistic multiterminal SNS-devices. Nonequilibrium is created by means of quasiparticle injection from a normal reservoir connected to the normal part of the junction. By applying a voltage at the normal reservoir the Josephson current can be suppressed or the direction of the current can be reversed. For a junction longer than the thermal length, LξTL\gg\xi_T, the nonequilibrium current increases linearly with applied voltage, saturating at a value equal to the equilibrium current of a short junction. The conductance exhibits a finite bias anomaly around eVvF/LeV \sim \hbar v_F/L. For symmetric injection, the conductance oscillates 2π2\pi-periodically with the phase difference ϕ\phi between the superconductors, with position of the minimum (ϕ=0\phi=0 or π\pi) dependent on applied voltage and temperature. For asymmetric injection, both the nonequilibrium Josephson current and the conductance becomes π\pi-periodic in phase difference. Inclusion of barriers at the NS-interfaces gives rise to a resonant behavior of the total Josephson current with respect to junction length with a period λF\sim \lambda_F. Both three and four terminal junctions are studied.Comment: 21 pages, 19 figures, submitted to Phys. Rev.

    Efficacy of the new long-acting formulation of lanreotide (lanreotide Autogel) in somatostatin analogue naive patients with acromegaly

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    ABSTRACT. Objective: To evaluate efficacy and safety of lanreotide autogel (ATG) 120 mg injections every 4-8 weeks in somatostatin analogue-na\uefve patients with acromegaly. Design: Open, non-comparative, phase III, multicenter clinical study. Methods: Fifty-one patients (28 women, aged 19-78 yr): 39 newly diagnosed (de novo) and 12 who had previously undergone unsuccessful surgery (post-op, 11 macro and 1 micro) were studied. ATG 120 mg was initially given every 8 weeks for 24 weeks and subsequently changed according to GH levels: if !2.5 \u3bcg/l every 8 weeks (group A, 17patients); if 2.5-5 \u3bcg/l every 6 weeks (group B, 15 patients); and if >5 \u3bcg/l every 4 weeks (group C, 19 patients). Treatment duration was 48-52 weeks. The primary objective was to control GH and IGF-I levels (GH!2.5 \u3bcg/l and IGF-I normalized for age/gender). Secondary objectives were to assessGH, IGF-I, and acid-labile subunit (ALS) decrease, improvement of clinical symptoms and quality of life (QoL). Results:GH levels normalized in 32 patients (63%), similarly in de novo and post-op patients (72% vs 50%, p=0.48); in100% of group A, in 73% of group B and in 21% of group C(p<0.0001). IGF-I levels normalized in 19 patients (37%), similarly in the de novo and post-op patients (33% vs 50%,p=0.48): in 65% of group A, 33% of group B, and in 16% of group C. Circulating GH levels decreased by 80\ub117%, IGF I levels by 44\ub127%, and ALS by 30\ub117%. Symptoms (hyperhidrosis (68.6%), swelling (68.6%), asthenia (58.8%),spine arthralgia (54.9%), and paresthesias (52.9%) and QoL(from 9.1\ub17.9 to 6.1\ub16.6) significantly improved (p<0.001).No patient withdrew from the study because of adverse events (AE). The most frequent AE was diarrhea (76.2% of patients): at study end 16 mild and 1 moderate diarrhea were recorded. Gallstones developed in 12% of patients. Conclusion: ATG 120 mg in somatostatin-na\uefve patients with acromegaly controls GH secretion in 63% and IGF-I secretion in 37% during a 48-52 week period without any difference between de novo and post-op patients. The treatment was associated with improvement in clinical symptoms and QoL and with a good, safe profile. (J. Endocrinol. Invest. 32: 202-209, 2009

    Baryons: What, When and Where?

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    We review the current state of empirical knowledge of the total budget of baryonic matter in the Universe as observed since the epoch of reionization. Our summary examines on three milestone redshifts since the reionization of H in the IGM, z = 3, 1, and 0, with emphasis on the endpoints. We review the observational techniques used to discover and characterize the phases of baryons. In the spirit of the meeting, the level is aimed at a diverse and non-expert audience and additional attention is given to describe how space missions expected to launch within the next decade will impact this scientific field.Comment: Proceedings Review for "Astrophysics in the Next Decade: JWST and Concurrent Facilities", ed. X. Tielens, 38 pages, 10 color figures. Revised to address comments from the communit

    Effect of a home based, low intensity, physical exercise program in older adults dialysis patients: A secondary analysis of the EXCITE trial

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    Background: Older adults dialysis patients represent the frailest subgroup of the End Stage Renal Disease (ESRD) population and physical exercise program may mitigate the age-related decline in muscle mass and function. Methods: Dialysis patients of the EXCITE trial aged > 65 years (n = 115, active arm, n = 53; control arm, n = 62) were submitted in random order to a home based, low intensity physical exercise program. At baseline and 6 months after exercise training 6-min walking distance (6MWD) and 5-time sit-to-stand test (5STS) were performed, and quality of life (QoL) was tested. Results: The training program improved both the 6MWD (6-months: 327 \ub1 86 m versus baseline: 294 \ub1 74 m; P < 0.001) and the 5STS time (6-months: 19.8 \ub1 5.6 s versus baseline: 22.5 \ub1 5.1 s; P < 0.001) in the exercise group whereas they did not change in the control group (P = 0.98 and 0.25, respectively). The between-arms differences (6 months-baseline) in the 6MWD (+ 34.0 m, 95% CI: 14.4 to 53.5 m) and in the 5STS time changes (- 1.9 s, 95% CI: -3.6 to - 0.3 s) were both statistically significant (P = 0.001 and P = 0.024, respectively). The cognitive function dimension of QoL significantly reduced in the control arm (P = 0.04) while it remained unchanged in the active arm (P = 0.78) (between groups difference P = 0.05). No patient died during the trial and the training program was well tolerated. Conclusions: This secondary analysis of the EXCITE trial shows that a home-based, exercise program improves physical performance and is well tolerated in elderly ESRD patients. Trial registration: The trial was registered in ClinicalTrials.Gov (Clinicaltrials.gov identifier: NCT01255969) on December 8, 2010

    NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

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    Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

    Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

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    We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society
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