First Detection of the Crab Pulsar above 100 GeV

We present the detection of pulsed gamma-ray emission from the Crab pulsar above 100 GeV with the VERITAS array of atmospheric Cherenkov telescopes. Gamma-ray emission at theses energies was not expected in pulsar models. The detection of pulsed emission above 100 GeV and the absence of an exponential cutoff makes it unlikely that curvature radiation is the primary production mechanism of gamma rays at these energies.Comment: 5 pages, proceedings of the TAUP 2011 conference in Munich, German

Mild-temperature hydrodeoxygenation of vanillin a typical bio-oil model compound to creosol a potential future biofuel

This study reports mild temperature hydrodeoxygenation (HDO) of vanillin an oxygenated phenolic compound found in bio-oil to creosol. It investigates the sensitivity of vanillin HDO reaction to changes in solvent, catalyst support and active metal type, and processing parameters using 100 ml batch reactor. The processing parameters considered include temperature (318 K – 338 K), hydrogen gas pressure (1 MPa – 3 MPa), catalyst loading (0.1 kg/m3 – 0.5 kg/m3), and agitation speed (500 rpm–900 rpm). As expected, significant variation in conversion and product selectivity was displayed in the results. Among the solvents considered, 2-propanol and ethyl acetate produced the best performance with conversion close to 100 % and selectivity toward creosol above 90 %. Remarkable differences were found in the H2 uptake during VL HDO reaction under different catalyst. The hierarchy in H2 uptake of the catalysts include: Pd/C > PdRh/Al2O3 > Pd/Al2O3 = Pt/C > Pt/SiO2 >> Rh/Al2O3. This was correlated to catalytic performance; Pd/C emerged as the best among the monometallic catalysts with 71 % selectivity toward creosol, but consumed 9 mmol of hydrogen per mol of vanillin converted. While the prepared bimetallic PdRh/Al2O3 catalyst consumed slightly lower amount of hydrogen (8 mmol), and produced significantly higher selectivity toward creosol (99 %). Even after three cycles the prepared catalyst demonstrated superior performance over the monometallic catalysts with selectivity toward creosol above 80 %. The reaction condition that maximises the degree of deoxygenation to creosol derived via Taguchi analysis includes temperature 338 K, hydrogen gas partial pressure 3.0 MPa, catalyst loading 0.5 kg/m3, and agitation speed 500 rpm

Gamma-Ray Emission from Two Blazars Behind the Galactic Plane: B2013+370 & B2023+336

B2013+370 and B2023+336 are two blazars at low-galactic latitude that were previously proposed to be the counterparts for the EGRET unidentified sources, 3EG J2016+3657 and 3EG J2027+3429. Gamma-ray emission associated with the EGRET sources has been detected by the Fermi Gamma-ray Space Telescope, and the two sources, 1FGL J2015.7+3708 and 1FGL J2027.6+3335, have been classified as unidentified in the 1-year catalog. This analysis of the Fermi-LAT data collected during 31 months reveals that the 1FGL sources are spatially compatible with the blazars, and are significantly variable, supporting the hypothesis of extragalactic origin for the gamma-ray emission. The gamma-ray light curves are compared with 15 GHz radio light curves from the 40-m telescope at the Owens Valley Radio Observatory (OVRO). Simultaneous variability is seen in both bands for the two blazar candidates. The study is completed with the X-ray analysis of 1FGL J2015.7+3708 using Swift observations that were triggered in August 2010 by a Fermi-detected flare. The resulting spectral energy distribution shows a two-component structure typical of blazars. We also identify a second source in the field of view of 1FGL J2027.6+3335 with similar characteristics to the known LAT pulsars. This study gives solid evidence favoring blazar counterparts for these two unidentified EGRET and Fermi sources, supporting the hypothesis that a number of unidentified gamma-ray sources at low galactic latitudes are indeed of extragalactic origin.Comment: 10 pages, 7 figures, 6 tables, accepted for publication in The Astrophysical Journa

Phase-resolved Crab pulsar measurements from 25 to 400 GeV with the MAGIC telescopes

We report on observations of the Crab pulsar with the MAGIC telescopes. Our data were taken in both monoscopic (> 25GeV) and stereoscopic (> 50GeV) observation modes. Two peaks were detected with both modes and phase-resolved energy spectra were calculated. By comparing with Fermi- LAT measurements, we find that the energy spectrum of the Crab pulsar does not follow a power law with an exponential cutoff, but has an additional hard component, extending up to at least 400 GeV. This suggests that the emission above 25 GeV is not dominated by curvature radiation, as suggested in the standard scenarios of the OG and SG models.Comment: 4 pages, 2 figures, Proc. TAUP 2011, submitted for publication in JCP

Approach to the virilizing girl at puberty

Virilization is the medical term for describing a female who develops characteristics associated with male hormones (androgens) at any age, or when a newborn girl shows signs of prenatal male hormone exposure at birth. In girls, androgen levels are low during pregnancy and childhood. A first physiologic rise of adrenal androgens is observed at the age of 6 to 8 years and reflects functional activation of the zona reticularis of the adrenal cortex at adrenarche, manifesting clinically with first pubic and axillary hairs. Early adrenarche is known as “premature adrenarche.” It is mostly idiopathic and of uncertain pathologic relevance but requires the exclusion of other causes of androgen excess (eg, nonclassic congenital adrenal hyperplasia) that might exacerbate clinically into virilization. The second modest physiologic increase of circulating androgens occurs then during pubertal development, which reflects the activation of ovarian steroidogenesis contributing to the peripheral androgen pool. However, at puberty initiation (and beyond), ovarian steroidogenesis is normally devoted to estrogen production for the development of secondary female bodily characteristics (eg, breast development). Serum total testosterone in a young adult woman is therefore about 10- to 20-fold lower than in a young man, whereas midcycle estradiol is about 10- to 20-fold higher. But if androgen production starts too early, progresses rapidly, and in marked excess (usually more than 3 to 5 times above normal), females will manifest with signs of virilization such as masculine habitus, deepening of the voice, severe acne, excessive facial and (male typical) body hair, clitoromegaly, and increased muscle development. Several medical conditions may cause virilization in girls and women, including androgen-producing tumors of the ovaries or adrenal cortex, (non)classical congenital adrenal hyperplasia and, more rarely, other disorders (also referred to as differences) of sex development (DSD). The purpose of this article is to describe the clinical approach to the girl with virilization at puberty, focusing on diagnostic challenges. The review is written from the perspective of the case of an 11.5-year-old girl who was referred to our clinic for progressive, rapid onset clitoromegaly, and was then diagnosed with a complex genetic form of DSD that led to abnormal testosterone production from a dysgenetic gonad at onset of puberty. Her genetic workup revealed a unique translocation of an abnormal duplicated Y-chromosome to a deleted chromosome 9, including the Doublesex and Mab-3 Related Transcription factor 1 (DMRT1) gene

Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics

Very-high energy (VHE) gamma quanta contribute only a minuscule fraction - below one per million - to the flux of cosmic rays. Nevertheless, being neutral particles they are currently the best "messengers" of processes from the relativistic/ultra-relativistic Universe because they can be extrapolated back to their origin. The window of VHE gamma rays was opened only in 1989 by the Whipple collaboration, reporting the observation of TeV gamma rays from the Crab nebula. After a slow start, this new field of research is now rapidly expanding with the discovery of more than 150 VHE gamma-ray emitting sources. Progress is intimately related with the steady improvement of detectors and rapidly increasing computing power. We give an overview of the early attempts before and around 1989 and the progress after the pioneering work of the Whipple collaboration. The main focus of this article is on the development of experimental techniques for Earth-bound gamma-ray detectors; consequently, more emphasis is given to those experiments that made an initial breakthrough rather than to the successors which often had and have a similar (sometimes even higher) scientific output as the pioneering experiments. The considered energy threshold is about 30 GeV. At lower energies, observations can presently only be performed with balloon or satellite-borne detectors. Irrespective of the stormy experimental progress, the success story could not have been called a success story without a broad scientific output. Therefore we conclude this article with a summary of the scientific rationales and main results achieved over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic rays, gamma rays and neutrinos: A survey of 100 years of research

Search for a Correlation Between Very-High-Energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar

We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ \u3e 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits

A new, very massive modular Liquid Argon Imaging Chamber to detect low energy off-axis neutrinos from the CNGS beam. (Project MODULAr)

The paper is considering an opportunity for the CERN/GranSasso (CNGS) neutrino complex, concurrent time-wise with T2K and NOvA, to search for theta_13 oscillations and CP violation. Compared with large water Cherenkov (T2K) and fine grained scintillators (NOvA), the LAr-TPC offers a higher detection efficiency and a lower backgrounds, since virtually all channels may be unambiguously recognized. The present proposal, called MODULAr, describes a 20 kt fiducial volume LAr-TPC, following very closely the technology developed for the ICARUS-T60o, and is focused on the following activities, for which we seek an extended international collaboration: (1) the neutrino beam from the CERN 400 GeV proton beam and an optimised horn focussing, eventually with an increased intensity in the framework of the LHC accelerator improvement program; (2) A new experimental area LNGS-B, of at least 50000 m3 at 10 km off-axis from the main Laboratory, eventually upgradable to larger sizes. A location is under consideration at about 1.2 km equivalent water depth; (3) A new LAr Imaging detector of at least 20 kt fiducial mass. Such an increase in the volume over the current ICARUS T600 needs to be carefully considered. It is concluded that a very large mass is best realised with a set of many identical, independent units, each of 5 kt, "cloning" the technology of the T600. Further phases may foresee extensions of MODULAr to meet future physics goals. The experiment might reasonably be operational in about 4/5 years, provided a new hall is excavated in the vicinity of the Gran Sasso Laboratory and adequate funding and participation are made available.Comment: Correspondig Author: C. Rubbia (E-mail: [email protected]), 33 pages, 11 figure

Analytic Calculation of Neutrino Mass Eigenvalues

Implicaion of the neutrino oscillation search for the neutrino mass square difference and mixing are discussed. We have considered the effective majorana mass m_{ee}, related for \beta\beta_{0\nu}decay. We find limits for neutrino mass eigen value m_{i} in the different neutrino mass spectrum,which explain the different neutrino data.Comment: 10 page