612 research outputs found

    Double-real contribution to the quark beam function at N3LO QCD

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    We compute the master integrals required for the calculation of the double-realemission contributions to the matching coefficients of 0-jettiness beam functions at next-to-next-to-next-to-leading order in perturbative QCD. As an application, we combine theseintegrals and derive the double-real gluon emission contribution to the matching coefficient Iqq(t;z) of the quark beam function

    Triple-real contribution to the quark beam function in QCD at next-to-next-to-next-to-leading order

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    JWST observations of stellar occultations by solar system bodies and rings

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    In this paper we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of solar system bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings, and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun-Earth Lagrange-point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a by-product of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.Comment: This paper is one of a series for a special issue on Solar System observations with JWST in PASP. Accepted 2-Oct-2015. Preprint 30 pages, 5 tables, 8 figure

    Grammatical comprehension in italian children with autism spectrum disorder

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    Language deficits represent one of the most relevant factors that determine the clinical phenotype of children with autism spectrum disorder (ASD). The main aim of the research was to study the grammatical comprehension of children with ASD. A sample of 70 well-diagnosed children (60 boys and 10 girls; aged 4.9–8 years) were prospectively recruited. The results showed that language comprehension is the most impaired language domain in ASD. These findings have important clinical implications, since the persistence of grammatical receptive deficits may have a negative impact on social, adaptive and learning achievements. As for the grammatical profiles, persistent difficulties were found during the school-age years in morphological and syntactic decoding in children with relatively preserved cognitive and expressive language skills. These data and the lack of a statistically significant correlation between the severity of ASD symptoms and language skills are in line with the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) perspective that considers the socio-communication disorder as a nuclear feature of ASD and the language disorder as a specifier of the diagnosis and not as a secondary symptom anymore. The presence of receptive difficulties in school-age ASD children with relatively preserved non-verbal cognitive abilities provides important hints to establish rehabilitative treatments

    Pontecorvo neutrino-antineutrino oscillations: theory and experimental limits

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    We study Pontecorvo neutrino-antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac-Majorana mass term. We find that matter effects suppress these oscillations and cannot explain the solar neutrino problem. On the contrary, a vacuum neutrino-antineutrino oscillations solution to this problem exists. We analyze this solution and available data from laboratory experiments giving stringent limits on νe\nu_e and νμ\nu_{\mu} Majorana masses.Comment: 11 pages, Latex2

    Effects of Probiotic Supplementation on Gastrointestinal, Sensory and Core Symptoms in Autism Spectrum Disorders: A Randomized Controlled Trial

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    The microbiota-gut-brain axis has been recently recognized as a key modulator of neuropsychiatric health. In this framework, probiotics (recently named “psychobiotics”) may modulate brain activity and function, possibly improving the behavioral profiles of children with Autism Spectrum Disorder (ASD). We evaluated the effects of probiotics on autism in a double-blind randomized, placebo-controlled trial of 85 preschoolers with ASD (mean age, 4.2 years; 84% boys). Participants were randomly assigned to probiotics (De Simone Formulation) (n=42) or placebo (n=43) for six months. Sixty-three (74%) children completed the trial. No differences between groups were detected on the primary outcome measure, the Total Autism Diagnostic Observation Schedule - Calibrated Severity Score (ADOS-CSS). An exploratory secondary analysis on subgroups of children with or without Gastrointestinal Symptoms (GI group, n= 30; NGI group, n=55) revealed in the NGI group treated with probiotics a significant decline in ADOS scores as compared to that in the placebo group, with a mean reduction of 0.81 in Total ADOS CSS and of 1.14 in Social-Affect ADOS CSS over six months. In the GI group treated with probiotics we found greater improvements in some GI symptoms, adaptive functioning, and sensory profiles than in the GI group treated with placebo. These results suggest potentially positive effects of probiotics on core autism symptoms in a subset of ASD children independent of the specific intermediation of the probiotic effect on GI symptoms. Further studies are warranted to replicate and extend these promising findings on a wider population with subsets of ASD patients which share targets of intervention on the microbiota-gut-brain axis. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT02708901

    A Combined Study on the Use of the Child Behavior Checklist 1½–5 for Identifying Autism Spectrum Disorders at 18 Months

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    The capacity of the Child Behavior Checklist 1½–5 (CBCL 1½–5) to identify children with autism spectrum disorder (ASD) at 18 months was tested on 37 children clinically referred for ASD and 46 children at elevated likelihood of developing ASD due to having an affected brother/sister. At 30 months the clinically referred children all received a confirmatory diagnosis, and 10 out of 46 siblings received a diagnosis of ASD. CBCL 1½-5 profiles were compared with a group of matched children with typical development (effect of cognitive level controlled for). The capacity of the CBCL 1½-5 DSM Oriented-Pervasive Developmental Problems scale to differentiate correctly between children diagnosed with ASD and children with typical development appeared dependent on group ascertainment methodology

    The structure of Chariklo's rings from stellar occultations

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    Two narrow and dense rings (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on 2013 June 3. Following this discovery, we planned observations of several occultations by Chariklo's system in order to better characterize the physical properties of the ring and main body. Here, we use 12 successful occulations by Chariklo observed between 2014 and 2016. They provide ring profiles (physical width, opacity, edge structure) and constraints on the radii and pole position. Our new observations are currently consistent with the circular ring solution and pole position, to within the ±3.3\pm 3.3 km formal uncertainty for the ring radii derived by Braga-Ribas et al. The six resolved C1R profiles reveal significant width variations from 5\sim 5 to 7.5 km. The width of the fainter ring C2R is less constrained, and may vary between 0.1 and 1 km. The inner and outer edges of C1R are consistent with infinitely sharp boundaries, with typical upper limits of one kilometer for the transition zone between the ring and empty space. No constraint on the sharpness of C2R's edges is available. A 1σ\sigma upper limit of 20\sim 20 m is derived for the equivalent width of narrow (physical width <4 km) rings up to distances of 12,000 km, counted in the ring plane

    Short-term variability of a sample of 29 trans-Neptunian objects and Centaurs

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    We present results of 6 years of observations, reduced and analyzed with the same tools in a systematic way. We report completely new data for 15 objects, for 5 objects we present a new analysis of previously published results plus additional data and for 9 objects we present a new analysis of data already published. Lightcurves, possible rotation periods and photometric amplitudes are reported for all of them. The photometric variability is smaller than previously thought: the mean amplitude of our sample is 0.1mag and only around 15% of our sample has a larger variability than 0.15mag. The smaller variability than previously thought seems to be a bias of previous observations. We find a very weak trend of faster spinning objects towards smaller sizes, which appears to be consistent with the fact that the smaller objects are more collisionally evolved, but could also be a specific feature of the Centaurs, the smallest objects in our sample. We also find that the smaller the objects, the larger their amplitude, which is also consistent with the idea that small objects are more collisionally evolved and thus more deformed. Average rotation rates from our work are 7.5h for the whole sample, 7.6h for the TNOs alone and 7.3h for the Centaurs. All of them appear to be somewhat faster than what one can derive from a compilation of the scientific literature and our own results. Maxwellian fits to the rotation rate distribution give mean values of 7.5h (for the whole sample) and 7.3h (for the TNOs only). Assuming hydrostatic equilibrium we can determine densities from our sample under the additional assumption that the lightcurves are dominated by shape effects, which is likely not realistic. The resulting average density is 0.92g/cm^3 which is not far from the density constraint that one can derive from the apparent spin barrier that we observe.Comment: Accepted for publication in A&

    4-Aminopyridine-induced epileptogenesis depends on activation of mitogen-activated protein kinase ERK

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    Extracellular signal-regulated kinases such as ERK1 [p44 mitogen-activated protein kinase (MAPK)] and ERK2 (p42 MAPK) are activated in the CNS under physiological and pathological conditions such as ischemia and epilepsy. Here, we studied the activation state of ERK1/2 in rat hippocampal slices during application of the K+ channel blocker 4-aminopyridine (4AP, 50 lM), a procedure that enhances synaptic transmission and leads to the appearance of epileptiform activity. Hippocampal slices superfused with 4AP-containing medium exhibited a marked activation of ERK1/2 phosphorylation that peaked within about 20 min. These effects were not accompanied by changes in the activation state of c-Jun N-terminal kinase (JNK), another member of the MAP kinase superfamily. 4AP-induced ERK1/2 activation was inhibited by the voltage-gated Na+ channel blocker tetrodotoxin (1 lM). We also found that application of the ERK pathway inhibitors U0126 (50 lM) or PD98059 (100 lM) markedly reduced 4AP-induced epileptiform synchronization, thus abolishing ictal discharges in the CA3 area. The effects induced by U0126 or PD98059 were not associated with changes in the amplitude and latency of the field potentials recorded in the CA3 area following electrical stimuli delivered in the dentate hylus. These data demonstrate that activation of ERK1/2 accompanies the appearance of epileptiform activity induced by 4AP and suggest a cause-effect relationship between the ERK pathway and epileptiform synchronization
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