ABSTRACT We report the Fermi Large Area Telescope (LAT) detections of high-energy (>100 MeV) γ-ray emission from two recent optically bright classical novae, V1369 Centauri 2013 and V5668 Sagittarii ...2015. At early times, Fermi target-of-opportunity observations prompted by their optical discoveries provided enhanced LAT exposure that enabled the detections of γ-ray onsets beginning ∼2 days after their first optical peaks. Significant γ-ray emission was found extending to 39-55 days after their initial LAT detections, with systematically fainter and longer-duration emission compared to previous γ-ray-detected classical novae. These novae were distinguished by multiple bright optical peaks that encompassed the time spans of the observed γ-rays. The γ-ray light curves and spectra of the two novae are presented along with representative hadronic and leptonic models, and comparisons with other novae detected by the LAT are discussed.
We present the analysis of Fermi Large Area Telescope gamma -ray observations of HB 21 (G89.0+4.7). We detect significant gamma -ray emission associated with the remnant; the flux > 100 MeV is 9.4 + ...or - 0.8 (stat) + or - 1.6 (syst) x 10 super(-11) erg cm super(-2) s super(-1). HB 21 is well modeled by a uniform disk centered at l = 88degrees.75 + or - 0degrees.04, b = +4degrees.65 + or - 0degrees.06 with a radius of 1degrees.19 + or - 0degrees.06. The gamma -ray spectrum shows clear evidence of curvature, suggesting a cutoff or break in the underlying particle population at an energy of a few GeV. We complement gamma -ray observations with the analysis of the WMAP 7 yr data from 23 to 93 GHz, achieving the first detection of HB 21 at these frequencies. In combination with archival radio data, the radio spectrum shows a special break, which helps to constrain the relativistic electron spectrum, and, in turn, parameters of simple non-thermal radiation models. In one-zone models multi wavelength data favor the origin of gamma rays from nucleon-nucleon collisions. A single population of electrons cannot produce both gamma rays through bremsstrahlung and radio emission through synchrotron radiation. A predominantly inverse-Compton origin of the gamma -ray emission is disfavored because it requires lower interstellar densities than are inferred for HB 21. In the hadronic-dominated scenarios, accelerated nuclei contribute a total energy of ~3 x 10 super(49) erg, while, in a two-zone bremsstrahlung-dominated scenario, the total energy in accelerated particles is ~1 x 10 super(49) erg.
Clear and data-driven bioregionalizations can provide a framework to test hypotheses and base biodiversity conservation. Here we used occurrence and abundance data in combination with objective ...analytical methods to propose two bioregionalization schemes for tree species of the Cerrado and the Pantanal in South America. We also evaluated the contribution of three sets of determinants of the occurrence- and abundance-based subregions. We compiled data on tree species composition from 894 local assemblages based on species occurrences, and from 658 local assemblages based on species abundances. We used an unconstrained community-level modelling approach and clustering techniques to identify and map tree subregions for the occurrence and the abundance data sets, separately. Hierarchical clustering analyses were conducted to investigate floristic affinities between the subregions and to map broader floristic regions. We used multinomial logistic regression models, deviance partitioning, and rank-sum tests to assess the main subregion correlates. We identified 18 occurrence- and four abundance-based subregions in the Cerrado-Pantanal. The hierarchical classifications grouped the occurrence-based subregions into nine floristic zones and abundance-based subregions into two broad floristic zones. Variation in subregions were explained mainly by environmental factors and spatial structure in both occurrence and abundance data sets. The occurrence- and abundance-based subregions are complementary approaches to disentangle macroecological patterns and to plan conservation efforts in the Cerrado and the Pantanal. Our findings based on occurrence data revealed more complex and interdigitated boundaries between subregions of tree species than previously reported. The environment, historical stability, and human effects act in a synergetic way on the distribution of the subregions. Finally, the relevance of contemporary environmental factors to the subregion patterns we found alert us to the profound impact global warming may have on the spatial organization of the Cerrado-Pantanal tree flora.
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The Cerrado savanna and Pantanal wetlands comprise 18 tree occurrence-based subregions and four abundance-based subregions.
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These subregions are complementary approaches that reveal concomitant macroecological patterns and help conservation planning.
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The Pantanal wetland is dominated by species in common with the Cerrado but has an exclusive set of rare species.
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The drivers of subregions floristic variation were mainly current environmental factors and spatial structure.
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The spatial organization of the Cerrado-Pantanal tree flora may suffer a profound impact due to global warming.
Abstract
Background
Isolated scaphotrapeziotrapezoid is a relatively rare condition, and there is still not complete consensus on the treatment of this pathology.
Purpose
The aim of the present ...study is to assess the utility of implant interposition after arthroscopic scaphoid distal pole resection for scaphotrapeziotrapezoid arthritis.
Material and Methods
The authors present a prospective study after the arthroscopic resection of the distal pole of the scaphoid in 24 patients. In a group of 11 patients, the simple resection was performed while in the other 13 patients the scaphoid resection and pyrocarbone implant interposition.
Results
All patients were clinically evaluated with disability of arm, shoulder, hand score. Dorsal intercalated segment instability deformity was also measured from X-ray analysis. Grip and pinch strength were measured too, and patients were also given a visual analog scale questionnaire. Both clinical and radiographic assessments were done at 24 months postoperatively.
Conclusions
The study showed comparable results with both the techniques.
Level of Evidence II
A prospective comparative study.
Background: Chronic exertional compartment syndrome of the forearm is an uncommon condition, occurring in some populations such as athletes. The standard surgical treatment for professional athletes ...who cannot avoid trigger activity is an open forearm fasciotomy, which may require a long recovery time. The aim of this study is to present a new endoscopic single approach forearm fasciotomy technique and outcomes of at least 3 years follow up.
Methods: We performed the endoscopic single approach forearm fasciotomy in 4 forearms in 3 men with the mean age of 25 years. All of the patients were evaluated at a mean follow up of 46 months using the Visual Analog Scale (VAS) for pain and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire.
Results: DASH improved from 21.71 to 5.39, VAS score improved too All the patients referred pain absence after the stress test performed at 20 kilos and 40 kilos. In our series no post-operative complications were observed.
Conclusions: The new mini-invasive technique has proved to be safe, reliable in a long-term follow-up. The main advantage is the shortening of the recovering time, that leads to a faster return to the professional activity.
With the amazing increasing in number of participants, rock climbing has become a popular sport in the last decade. A growing number of participants, with different skill level, inevitably leads to ...an increased number of injuries related to this practice. The kind of lesions that can be observed in rock-climbers is very specific and often involves the hand. For this reason is very important for any hand surgeon that is exposed to sport injuries to know which and the most common injuries related to this sport and which are the basic principles for the treatment of those. The aim of this article is to review the literature that has been published in the last ten year in this topic. On the NCBI database 22 articles where found that where related to rock climbing lesion affecting the hand or the whole body. Differences where found according to kind of rock climbing activity that was analyzed, alpine climb leads to more serious injuries, often affecting the lower limb, while in sport and recreational rock climbing the upper limb and the hand are definitely the most affected parts. Flexor pulley lesions, followed by fractures and strains are the most common lesions affecting the hand that are related to this practice.
The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some of the most dark matter (DM) dominated objects known. We report on γ-ray observations of Milky Way dSphs based on six years ...of Fermi Large Area Telescope data processed with the new Pass8 event-level analysis. None of the dSphs are significantly detected in γ rays, and we present upper limits on the DM annihilation cross section from a combined analysis of 15 dSphs. These constraints are among the strongest and most robust to date and lie below the canonical thermal relic cross section for DM of mass ≲100 GeV annihilating via quark and τ-lepton channels.
We report on the search for spectral irregularities induced by oscillations between photons and axion-like particles (ALPs) in the gamma-ray spectrum of NGC 1275, the central galaxy of the Perseus ...cluster. Using 6 years of Fermi Large Area Telescope data, we find no evidence for ALPs and exclude couplings above 5 times 10 (sup -12) per gigaelectronvolt for ALP masses less than or approximately equal to 0.5 apparent magnitude (m (sub a)) less than or approximately equal to 5 nanoelectronvolts at 95 percent confidence. The limits are competitive withthe sensitivity of planned laboratory experiments, and, together with other bounds, strongly constrain thepossibility that ALPs can reduce the gamma-ray opacity of the Universe.
We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the ...spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of 3.07±0.02(stat+syst)±0.04(energy measurement). An exponential cutoff lower than 1.8 TeV is excluded at 95% CL.
The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with ...Pass 8, the newest event-level analysis, which significantly improves the acceptance and angular resolution of the instrument. Most of the 2FHL sources at high Galactic latitude are blazars. Using detailed Monte Carlo simulations, we measure, for the first time, the source count distribution, dN/dS, of extragalactic γ-ray sources at E>50 GeV and find that it is compatible with a Euclidean distribution down to the lowest measured source flux in the 2FHL (∼8×10^{-12} ph cm^{-2} s^{-1}). We employ a one-point photon fluctuation analysis to constrain the behavior of dN/dS below the source detection threshold. Overall, the source count distribution is constrained over three decades in flux and found compatible with a broken power law with a break flux, S_{b}, in the range 8×10^{-12},1.5×10^{-11} ph cm^{-2} s^{-1} and power-law indices below and above the break of α_{2}∈1.60,1.75 and α_{1}=2.49±0.12, respectively. Integration of dN/dS shows that point sources account for at least 86_{-14}^{+16}% of the total extragalactic γ-ray background. The simple form of the derived source count distribution is consistent with a single population (i.e., blazars) dominating the source counts to the minimum flux explored by this analysis. We estimate the density of sources detectable in blind surveys that will be performed in the coming years by the Cherenkov Telescope Array.
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