Showing papers by "University of Perugia published in 2010"
TL;DR: The first Fermi-LAT catalog (1FGL) as mentioned in this paper contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma.
Abstract: We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), the primary science instrument on the Fermi Gamma-ray Space Telescope (Fermi), during the first 11 months of the science phase of the mission, which began on 2008 August 4. The First Fermi-LAT catalog (1FGL) contains 1451 sources detected and characterized in the 100 MeV to 100 GeV range. Source detection was based on the average flux over the 11 month period, and the threshold likelihood Test Statistic is 25, corresponding to a significance of just over 4 sigma. The 1FGL catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and power-law spectral fits as well as flux measurements in five energy bands for each source. In addition, monthly light curves are provided. Using a protocol defined before launch we have tested for several populations of gamma-ray sources among the sources in the catalog. For individual LAT-detected sources we provide firm identifications or plausible associations with sources in other astronomical catalogs. Identifications are based on correlated variability with counterparts at other wavelengths, or on spin or orbital periodicity. For the catalogs and association criteria that we have selected, 630 of the sources are unassociated. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, with the result that 161 sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having properties that are strongly dependent on the model or as potentially being due to incorrectly modeled structure in the Galactic diffuse emission.
1,412 citations
TL;DR: It is acknowledged that a single cure for Alzheimer's disease is unlikely to be found and that the approach to drug development for this disorder needs to be reconsidered, but several promising randomised controlled trials are ongoing and increased collaboration between pharmaceutical companies, basic researchers, and clinical researchers has the potential to bring us closer to developing an optimum pharmaceutical approach.
Abstract: Alzheimer's disease is the most common cause of dementia in elderly people. Research into Alzheimer's disease therapy has been at least partly successful in terms of developing symptomatic treatments, but has also had several failures in terms of developing disease-modifying therapies. These successes and failures have led to debate about the potential deficiencies in our understanding of the pathogenesis of Alzheimer's disease and potential pitfalls in diagnosis, choice of therapeutic targets, development of drug candidates, and design of clinical trials. Many clinical and experimental studies are ongoing, but we need to acknowledge that a single cure for Alzheimer's disease is unlikely to be found and that the approach to drug development for this disorder needs to be reconsidered. Preclinical research is constantly providing us with new information on pieces of the complex Alzheimer's disease puzzle, and an analysis of this information might reveal patterns of pharmacological interactions instead of single potential drug targets. Several promising randomised controlled trials are ongoing, and the increased collaboration between pharmaceutical companies, basic researchers, and clinical researchers has the potential to bring us closer to developing an optimum pharmaceutical approach for the treatment of Alzheimer's disease.
1,134 citations
TL;DR: In this paper, Kalogera et al. presented an up-to-date summary of the rates for all types of compact binary coalescence sources detectable by the initial and advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo.
Abstract: We present an up-to-date, comprehensive summary of the rates for all types of compact binary coalescence sources detectable by the initial and advanced versions of the ground-based gravitational-wave detectors LIGO and Virgo. Astrophysical estimates for compact-binary coalescence rates depend on a number of assumptions and unknown model parameters and are still uncertain. The most confident among these estimates are the rate predictions for coalescing binary neutron stars which are based on extrapolations from observed binary pulsars in our galaxy. These yield a likely coalescence rate of 100 Myr−1 per Milky Way Equivalent Galaxy (MWEG), although the rate could plausibly range from 1 Myr−1 MWEG−1 to 1000 Myr−1 MWEG−1 (Kalogera et al 2004 Astrophys. J. 601 L179; Kalogera et al 2004 Astrophys. J. 614 L137 (erratum)). We convert coalescence rates into detection rates based on data from the LIGO S5 and Virgo VSR2 science runs and projected sensitivities for our advanced detectors. Using the detector sensitivities derived from these data, we find a likely detection rate of 0.02 per year for Initial LIGO–Virgo interferometers, with a plausible range between 2 × 10−4 and 0.2 per year. The likely binary neutron–star detection rate for the Advanced LIGO–Virgo network increases to 40 events per year, with a range between 0.4 and 400 per year.
1,011 citations
TL;DR: The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented in this article, which includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs.
Abstract: The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The second LAT AGN catalog (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. However, some of these are affected by analysis issues and some are associated with multiple AGNs. Consequently, we define a Clean Sample which includes 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310 flat-spectrum radio quasars (FSRQs), 157 candidate blazars of unknown type (i.e., with broadband blazar characteristics but with no optical spectral measurement yet), 8 misaligned AGNs, 4 narrow-line Seyfert 1 (NLS1s), 10 AGNs of other types, and 2 starburst galaxies. Where possible, the blazars have been further classified based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. While almost all FSRQs have a synchrotron-peak frequency 1015 Hz. The 2LAC represents a significant improvement relative to the first LAT AGN catalog (1LAC), with 52% more associated sources. The full characterization of the newly detected sources will require more broadband data. Various properties, such as γ-ray fluxes and photon power-law spectral indices, redshifts, γ-ray luminosities, variability, and archival radio luminosities and their correlations are presented and discussed for the different blazar classes. The general trends observed in 1LAC are confirmed.
981 citations
Abstract: We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log nu-log nu F-nu representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low-and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(ro), and optical to X-ray, alpha(ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (nu(S)(peak)) is positioned between 10(12.5) and 10(14.5) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(13) and 10(17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter gamma-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum gamma-ray sources, the correlation between nu(S)(peak) and gamma-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars.
882 citations
TL;DR: In this article, different results on the fabrication of nanocomposites based on biodegradable polymers for specific field of tissue engineering are presented, and the combination of bioresorbable polymer and nanostructures open new perspectives in the self-assembly of nanomaterials for biomedical applications with tuneable mechanical, thermal and electrical properties.
850 citations
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2197 more•Institutions (149)
TL;DR: The pre-print version of the Published Article can be accessed from the link below - Copyright @ 2010 Springer Verlag as discussed by the authors, which can be viewed as a preprint of the published article.
Abstract: This is the pre-print version of the Published Article, which can be accessed from the link below - Copyright @ 2010 Springer Verlag
717 citations
TL;DR: The first Fermi Large Area Telescope measurements of the so-called "extragalactic" diffuse gamma-ray emission (EGB) are reported, finding the spectrum is featureless, less intense, and softer than that derived from EGRET data.
Abstract: We report on the first Fermi Large Area Telescope (LAT) measurements of the so-called "extra-galactic" diffuse gamma-ray emission (EGB). This component of the diffuse gamma-ray emission is generally considered to have an isotropic or nearly isotropic distribution on the sky with diverse contributions discussed in the literature. The derivation of the EGB is based on detailed modelling of the bright foreground diffuse Galactic gamma-ray emission (DGE), the detected LAT sources and the solar gamma-ray emission. We find the spectrum of the EGB is consistent with a power law with differential spectral index g = 2.41+/-0.05 and intensity, I(> 100 MeV) = (1.03+/-0.17) 10^-5 cm^-2 s^-1 sr^-1, where the error is systematics dominated. Our EGB spectrum is featureless, less intense, and softer than that derived from EGRET data.
582 citations
TL;DR: The first catalog of active galactic nuclei (AGN) detected by the LAT, corresponding to 11 months of data collected in scientific operation mode, is presented in this article, which includes 671 gamma-ray sources located at high Galactic latitudes (|b| > 10 deg) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs.
Abstract: We present the first catalog of active galactic nuclei (AGN) detected by the LAT, corresponding to 11 months of data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 gamma-ray sources located at high Galactic latitudes (|b| > 10 deg) that are detected with a test statistic (TS) greater than 25 and associated statistically with AGNs. Some LAT sources are associated with multiple AGNs, and consequently, the catalog includes 709 AGNs, comprising 300 BL Lacertae objects (BL Lacs), 296 flat-spectrum radio quasars (FSRQs), 41 AGNs of other types, and 72 AGNs of unknown type. We also classify the blazars based on their spectral energy distributions (SEDs) as archival radio, optical, and X-ray data permit. In addition to the format 1LAC sample, we provide AGN associations for 51 low-latitude LAT sources and AGN "affiliations" (unquantified counterpart candidates) for 104 high-latitude LAT sources without AGN associations. The overlap of the 1LAC with existing gamma-ray AGN catalogs (LBAS, EGRET, AGILE, Swift, INTEGRAL, TeVCat) is briefly discussed. Various properties--such as gamma-ray fluxes and photon power law spectral indices, redshifts, gamma-ray luminosities, variability, and archival radio luminosities--and their correlations are presented and discussed for the different blazar classes. We compare the 1LAC results with predictions regarding the gamma-ray AGN populations, and we comment on the power of the sample to address the question of the blazar sequence.
536 citations
TL;DR: In this article, the authors presented 46 high-confidence pulsed detections using the first six months of data taken by the Large Area Telescope (LAT), Fermi's main instrument.
Abstract: The dramatic increase in the number of known gamma-ray pulsars since the launch of the Fermi Gamma-ray Space Telescope (formerly GLAST) offers the first opportunity to study a population of these high-energy objects. This catalog summarizes 46 high-confidence pulsed detections using the first six months of data taken by the Large Area Telescope (LAT), Fermi's main instrument. Sixteen previously unknown pulsars were discovered by searching for pulsed signals at the positions of bright gamma-ray sources seen with the LAT, or at the positions of objects suspected to be neutron stars based on observations at other wavelengths. Pulsed gamma-ray emission was discovered from twenty-four known pulsars by using ephemerides (timing solutions) derived from monitoring radio pulsars. Eight of these new gamma-ray pulsars are millisecond pulsars. The pulsed energy spectra can be described by a power law with an exponential cutoff, with cutoff energies in the range 1 to 5 GeV. The rotational energy loss rate (\dot{E}) of these neutron stars spans 5 decades, from ~3x10^{33} erg/s to 5x10^{38} erg/s, and the apparent efficiencies for conversion to gamma-ray emission range from ~0.1% to unity, although distance uncertainties complicate efficiency estimates. The pulse shapes show substantial diversity, but roughly 75% of the gamma-ray pulse profiles have two peaks, separated by >0.2 of rotational phase. For most of the pulsars, gamma-ray emission appears to come mainly from the outer magnetosphere, while polar-cap emission remains plausible for a remaining few. Finally, these discoveries suggest that gamma-ray-selected young pulsars are born at a rate comparable to that of their radio-selected cousins and that the birthrate of all young gamma-ray-detected pulsars is a substantial fraction of the expected Galactic supernova rate.
512 citations
TL;DR: In this article, the authors performed searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon with the entire data set of (963 +/- 7) x 10(6) tau decays collected by the BABAR detector near the Y(4S), Y(3S) and Y(2S) resonances.
Abstract: Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963 +/- 7) x 10(6) tau decays collected by the BABAR detector near the Y(4S), Y(3S) and Y(2S) resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of B(tau(+/-) -> e(+/-)gamma) mu(+/-)gamma) < 4.4 X 10(-8) at 90% confidence level.
Vardan Khachatryan, Albert M. Sirunyan, Armen Tumasyan, Wolfgang Adam1 +2087 more•Institutions (132)
TL;DR: In this article, the authors measured the transverse momentum and pseudorapidity distributions in proton-proton collisions at root s = 7 TeV with the inner tracking system of the CMS detector at the LHC.
Abstract: Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at root s = 7 TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/d eta vertical bar(vertical bar eta vertical bar<0.5) = 5.78 +/- 0.01(stat) +/- 0.23(stat) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from root s = 0.9 to 7 TeV is [66.1 +/- 1.0(stat) +/- 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 +/- 0.005(stat) +/- 0.015(syst) GeV/c. The results are compared with similar measurements at lower energies.
TL;DR: In this article, the morphology of the technical fibres of the Malvaceae family (Abelmoschus esculentus) was investigated through optical and electron microscopy and their thermal behaviour through thermogravimetric analysis.
TL;DR: In this paper, the authors evaluated the efficacy, complication, and reoperation rates of midurethral tapes compared with other surgical treatments for female SUI, and found that patients treated with RT experienced slightly higher continence rates than those treated with Burch colposuspension, but they faced a much higher risk of intraoperative complications.
TL;DR: The most important aspects of the pathogenesis and development of endothelial dysfunction are summarized, with particular attention to the role of traditional CV risk factors, the usefulness of vasoreactivity tests, and the future perspectives opened by genetic studies.
TL;DR: In this paper, a catalogue of 753 rainfall events that have resulted in landslides in Italy was compiled and used to determine the minimum rainfall conditions necessary for landslide occurrence in Italy and in the Abruzzo Region, central Italy.
Abstract: . In Italy, rainfall is the primary trigger of landslides that frequently cause fatalities and large economic damage. Using a variety of information sources, we have compiled a catalogue listing 753 rainfall events that have resulted in landslides in Italy. For each event in the catalogue, the exact or approximate location of the landslide and the time or period of initiation of the slope failure is known, together with information on the rainfall duration D, and the rainfall mean intensity I, that have resulted in the slope failure. The catalogue represents the single largest collection of information on rainfall-induced landslides in Italy, and was exploited to determine the minimum rainfall conditions necessary for landslide occurrence in Italy, and in the Abruzzo Region, central Italy. For the purpose, new national rainfall thresholds for Italy and new regional rainfall thresholds for the Abruzzo Region were established, using two independent statistical methods, including a Bayesian inference method and a new Frequentist approach. The two methods proved complementary, with the Bayesian method more suited to analyze small data sets, and the Frequentist method performing better when applied to large data sets. The new regional thresholds for the Abruzzo Region are lower than the new national thresholds for Italy, and lower than the regional thresholds proposed in the literature for the Piedmont and Lombardy Regions in northern Italy, and for the Campania Region in southern Italy. This is important, because it shows that landslides in Italy can be triggered by less severe rainfall conditions than previously recognized. The Frequentist method experimented in this work allows for the definition of multiple minimum rainfall thresholds, each based on a different exceedance probability level. This makes the thresholds suited for the design of probabilistic schemes for the prediction of rainfall-induced landslides. A scheme based on four probabilistic thresholds is proposed. The four thresholds separate five fields, each characterized by different rainfall intensity-duration conditions, and corresponding different probability of possible landslide occurrence. The scheme can be implemented in landslide warning systems that operate on rainfall thresholds, and on precipitation measurements or forecasts.
TL;DR: Low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied over a 6-year period, which raises important new possibilities for treatment and prevention.
Abstract: Background: To our knowledge, no prospective study has examined the association between vitamin D and cognitive decline or dementia. Methods: We determined whether low levels of serum 25-hydroxyvitamin D (25[OH]D) were associated with an increased risk of substantial cognitive decline in the InCHIANTI population–based study conducted in Italy between 1998 and 2006 with follow-up assessments every 3 years. A total of 858 adults 65 years or older completed interviews, cognitive assessments, and medical examinations and provided blood samples. Cognitive decline was assessed using the Mini-Mental State Examination (MMSE), and substantial decline was defined as 3 or more points. The Trail-Making Tests A and B were also used, and substantial decline was defined as the worst 10% of the distribution of decline or as discontinued testing. Results: The multivariate adjusted relative risk (95% confidence interval [CI]) of substantial cognitive decline on the MMSE in participants who were severely serum 25 (OH)D deficient (levels25 nmol/L) in comparison with those with sufficient levels of 25(OH)D (75 nmol/L) was 1.60 (95% CI, 1.19-2.00). Multivariate adjusted random-effects models demonstrated that the scores of participants who were severely 25(OH)D deficient declined by an additional 0.3 MMSE points per year more than those with sufficient levels of 25(OH)D. The relative risk for substantial decline on Trail-Making Test B was 1.31 (95% CI, 1.03-1.51) among those who were severely 25(OH)D deficient compared with those with sufficient levels of 25(OH)D. No significant association was observed for Trail-Making Test A. Conclusion: Low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied over a 6-year period, which raises important new possibilities for treatment and prevention. Arch Intern Med. 2010;170(13):1135-1141
TL;DR: The history, chemistry, and factors governing the intestinal bacterial formation of equol, a metabolite of the soy isoflavones, are described and the wide range of biological activities these enantiomers possess warrants their investigation for the treatment of a number of hormone-related conditions involving estrogen-dependent and androgen- related conditions.
Abstract: Equol, first isolated from equine urine in 1932 and identified 50 years later in human urine as a metabolite of the soy isoflavones, daidzin and daidzein, is produced by intestinal bacteria in some, but not all, adults. This observation led to the term equol-producers to define those adults that could make equol in response to consuming soy isoflavones and the hypothesis that the health benefits of soy-based diets may be greater in equol-producers than in equol nonproducers. By virtue of a chiral center, equol occurs as a diastereoisomer and intestinal bacteria are enantiospecific in synthesizing exclusively the S-(-)equol enantiomer, an enantiomer that has selective affinity for the estrogen receptor-β. Both enantiomers are of interest from a clinical and pharmacological perspective and are currently being developed as nutraceutical and pharmacological agents. The wide range of biological activities these enantiomers possess warrants their investigation for the treatment of a number of hormone-related conditions involving estrogen-dependent and androgen-related conditions. The following review describes the history, chemistry, and factors governing the intestinal bacterial formation of equol.
TL;DR: In this article, the authors present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gammaray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory.
Abstract: We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gammaray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E-peak = 3.9 +/- 0.3 MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 +/- 0.03 that dominates the emission below approximate to 20 keV and above approximate to 100 MeV. The onset of the high-energy spectral component appears to be delayed by similar to 0.1 s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5 s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5(-2.6)(+5.8) GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Gamma greater than or similar to 1200, using simple.. opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the approximate to 100 keV-few MeV flux. Stricter high confidence estimates imply Gamma greater than or similar to 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.
TL;DR: The use of an add-on package for the R statistical software is described, which allows for the estimation of the semiparametric proportional hazards model for the subdistribution of a competing risk analysis as proposed by Fine and Gray.
Abstract: We describe how to conduct a regression analysis for competing risks data. The use of an add-on package for the R statistical software is described, which allows for the estimation of the semiparametric proportional hazards model for the subdistribution of a competing risk analysis as proposed by Fine and Gray. J Am Stat Assoc 1999; 94: 496-509.
TL;DR: In this article, the authors present light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS) weekly light curves of this sample, obtained during the first 11 months of the FERi survey (2008 August 4-2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis.
Abstract: This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS) Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4–2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks Variable sources of the sample have weekly and 3–4 day bin light curves that can be described by 1/f α PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)—measured for a few blazars showing strong activity—complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 15 and 17, respectively The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars
TL;DR: This review focuses on the optimal diagnostic strategy and management, according to the clinical presentation, for Pulmonary embolism.
Abstract: Pulmonary embolism should be suspected in all patients who present with new or worsening dyspnea, chest pain, or sustained hypotension without a clear alternative cause. This review focuses on the optimal diagnostic strategy and management, according to the clinical presentation.
TL;DR: In this paper, a gamma (γ)-ray flare with a dramatic change of optical polarization angle is reported, which provides evidence for co-spatiality of optical and γ-ray emission regions and indicates a highly ordered jet magnetic field.
Abstract: It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight1. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma (γ)-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and γ-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 105 gravitational radii.
King's College London1, Karolinska Institutet2, Wolfson Centre for Age-Related Diseases3, Roskilde University4, University of Perugia5, University of Eastern Finland6, Aristotle University of Thessaloniki7, GlaxoSmithKline8, National Institutes of Health9, Johns Hopkins University10, McGill University11
TL;DR: These results demonstrate an important role of clusterin in the pathogenesis of AD and suggest that alterations in amyloid chaperone proteins may be a biologically relevant peripheral signature of AD.
Abstract: CONTEXT: Blood-based analytes may be indicators of pathological processes in Alzheimer disease (AD). OBJECTIVE: To identify plasma proteins associated with AD pathology using a combined proteomic and neuroimaging approach. DESIGN: Discovery-phase proteomics to identify plasma proteins associated with correlates of AD pathology. Confirmation and validation using immunodetection in a replication set and an animal model. SETTING: A multicenter European study (AddNeuroMed) and the Baltimore Longitudinal Study of Aging. PARTICIPANTS: Patients with AD, subjects with mild cognitive impairment, and healthy controls with standardized clinical assessments and structural neuroimaging. MAIN OUTCOME MEASURES: Association of plasma proteins with brain atrophy, disease severity, and rate of clinical progression. Extension studies in humans and transgenic mice tested the association between plasma proteins and brain amyloid. RESULTS: Clusterin/apolipoprotein J was associated with atrophy of the entorhinal cortex, baseline disease severity, and rapid clinical progression in AD. Increased plasma concentration of clusterin was predictive of greater fibrillar amyloid-beta burden in the medial temporal lobe. Subjects with AD had increased clusterin messenger RNA in blood, but there was no effect of single-nucleotide polymorphisms in the gene encoding clusterin with gene or protein expression. APP/PS1 transgenic mice showed increased plasma clusterin, age-dependent increase in brain clusterin, as well as amyloid and clusterin colocalization in plaques. CONCLUSIONS: These results demonstrate an important role of clusterin in the pathogenesis of AD and suggest that alterations in amyloid chaperone proteins may be a biologically relevant peripheral signature of AD.
TL;DR: The evidence for and against the hypothesis that hypoglycemia is a risk factor for cardiovascular events is discussed, and the possible mechanisms that might be involved are discussed.
Abstract: Diabetes is at epidemic proportions in the U.S. Patients with diabetes are at increased risk for micro- and macrovascular complications. The benefit of glycemic control in decreasing the risk for microvascular disease is well established. However, the role of glycemic control in decreasing macrovascular complications has been controversial. Several large clinical trials looking at this issue have either shown no benefit or even potential harm. The possibility of hypoglycemia as a risk factor for cardiovascular events is a topic of much debate. In this review article, we discuss the evidence for and against this hypothesis and the possible mechanisms that might be involved.
Patients with diabetes have an increased risk of cardiovascular disease. The link between glycemic control and microvascular complications has been firmly established (1,2). However, the association between glycemic control and macrovascular disease is mainly obtained from epidemiological studies, and intensive glucose control has often failed to reduce macrovascular events. Intensive glucose control invariably increases the risk of hypoglycemia and sometimes the severity of hypoglycemia (2) Several epidemiological studies and smaller prospective studies have linked hypoglycemia to increased cardiovascular risk (3⇓–5). Recent large randomized trials looking at intensive glycemic control have either shown no benefit (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation [ADVANCE] and Veterans Affairs Diabetes Trial [VADT]) or increased all cause mortality (Action to Control Cardiovascular Risk in Diabetes [ACCORD]) (6). While the reason for the increased mortality is unclear and hypoglycemia has not been implicated as a cause of death, these studies have increased the debate about the degree of glycemic control required to decrease diabetes complications and the role of hypoglycemia in cardiovascular morbidity and mortality.
The modern definition of hypoglycemia is plasma glucose <70 mg/dl (7⇓–9). At plasma glucose …
Sheba Medical Center1, University of Münster2, University of Zurich3, University of Colorado Denver4, University of Toronto5, McMaster University6, University of California, San Francisco7, Harvard University8, Otto-von-Guericke University Magdeburg9, Goethe University Frankfurt10, Charité11, University of Perugia12, University of Kiel13, Southampton General Hospital14, University College London15, Ludwig Maximilian University of Munich16, National Institutes of Health17, Medical University of Vienna18, Royal Children's Hospital19, University of Amsterdam20, University of Pennsylvania21, Innsbruck Medical University22, University of Padua23, University of Southern California24
TL;DR: It is indicated that thrombophilias serve as risk factors for incident stroke through a meta-analysis of published observational studies and no significant heterogeneity was discerned across studies, and no publication bias was detected.
Abstract: BACKGROUND: The aim of this study was to estimate the impact of thrombophilia on risk of first childhood stroke through a meta-analysis of published observational studies. METHODS AND RESULTS: A systematic search of electronic databases (Medline via PubMed, EMBASE, OVID, Web of Science, The Cochrane Library) for studies published from 1970 to 2009 was conducted. Data on year of publication, study design, country of origin, number of patients/control subjects, ethnicity, stroke type (arterial ischemic stroke [AIS], cerebral venous sinus thrombosis [CSVT]) were abstracted. Publication bias indicator and heterogeneity across studies were evaluated, and summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with fixed-effects or random-effects models. Twenty-two of 185 references met inclusion criteria. Thus, 1764 patients (arterial ischemic stroke [AIS], 1526; cerebral sinus venous thrombosis [CSVT], 238) and 2799 control subjects (neonate to 18 years of age) were enrolled. No significant heterogeneity was discerned across studies, and no publication bias was detected. A statistically significant association with first stroke was demonstrated for each thrombophilia trait evaluated, with no difference found between AIS and CSVT. Summary ORs (fixed-effects model) were as follows: antithrombin deficiency, 7.06 (95% CI, 2.44 to 22.42); protein C deficiency, 8.76 (95% CI, 4.53 to 16.96); protein S deficiency, 3.20 (95% CI, 1.22 to 8.40), factor V G1691A, 3.26 (95% CI, 2.59 to 4.10); factor II G20210A, 2.43 (95% CI, 1.67 to 3.51); MTHFR C677T (AIS), 1.58 (95% CI, 1.20 to 2.08); antiphospholipid antibodies (AIS), 6.95 (95% CI, 3.67 to 13.14); elevated lipoprotein(a), 6.27 (95% CI, 4.52 to 8.69), and combined thrombophilias, 11.86 (95% CI, 5.93 to 23.73). In the 6 exclusively perinatal AIS studies, summary ORs were as follows: factor V, 3.56 (95% CI, 2.29 to 5.53); and factor II, 2.02 (95% CI, 1.02 to 3.99). CONCLUSIONS: The present meta-analysis indicates that thrombophilias serve as risk factors for incident stroke. However, the impact of thrombophilias on outcome and recurrence risk needs to be further investigated.
TL;DR: The protocol was amended and patients in both arms received once-weekly instead of the initial twice-weekly bortezomib infusions to decrease neurologic toxicities, and an improvement in safety did not appear to affect efficacy.
TL;DR: In this paper, the results of analysis of cosmic-ray electrons using about 8 x 10(6) electron candidates detected in the first 12 months on-orbit by the Fermi Large Area Telescope were presented.
Abstract: We present the results of our analysis of cosmic-ray electrons using about 8 x 10(6) electron candidates detected in the first 12 months on-orbit by the Fermi Large Area Telescope. This work extend ...
TL;DR: Assessment of the effect of FXR activation by 6-ethyl-chenodeoxycholic acid, (6E-CDCA, 10 mg/kg) on insulin resistance and liver and muscle lipid metabolism in fa/fa rats and compared its activity with rosiglitazone found it to be protective against body weight gain, correct lipid metabolism abnormalities in an obesity animal model.
TL;DR: Optical scattering by PNB and its diameter has been varied with the fluence of laser pulse, and this has demonstrated the tunable nature of PNB.
Abstract: We have used short laser pulses to generate transient vapor nanobubbles around plasmonic nanoparticles. The photothermal, mechanical, and optical properties of such bubbles were found to be different from those of plasmonic nanoparticle and vapor bubbles, as well. This phenomenon was considered as a new complex nanosystem—plasmonic nanobubble (PNB). Mechanical and optical scattering properties of PNB depended upon the nanoparticle surface and heat capacity, clusterization state, and the optical pulse length. The generation of the PNB required much higher laser pulse fluence thresholds than the explosive boiling level and was characterized by the relatively high lower threshold of the minimal size (lifetime) of PNB. Optical scattering by PNB and its diameter (measured as the lifetime) has been varied with the fluence of laser pulse, and this has demonstrated the tunable nature of PNB.