The Extremely Luminous Quasar Survey in the Pan-STARRS 1 Footprint (PS-ELQS)

We present the results of the Extremely Luminous Quasar Survey in the $3\pi$ survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint ($\sim12,000\,\rm{deg}^2$) to a much larger area ($\sim\rm{21486}\,\rm{deg}^2$). This spectroscopic survey targets the most luminous quasars ($M_{1450}\le-26.5$; $m_{i}\le18.5$) at intermediate redshifts ($z\ge2.8$). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts ($z_{\rm{reg}}$) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at $z_{\rm{reg}}\ge2.8$ from a parent sample of 74318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new $z\ge2.8$ quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at $z\ge2.8$, our quasar selection method has a selection efficiency of at least $77\%$. At lower declinations $-30\le\rm{Decl.}\le0$ we approximately triple the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars ($m_{i}\le18.5$, $z\ge2.8$). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.Comment: 34 pages, 10 figures, accepted to ApJ

Preface : causes of obesity, theories, conjectures and evidence

Peer reviewedPublisher PD

Public Awareness of Medical Imaging as a Source of Ionizing Radiation Exposure

Background. Biological effects of exposure to ionizing radiation (IR) are well known. Literature suggests most patients and physicians lack proficient understanding of risks associated with ionizing radiation. Our study goals were to: assess the extent to which productive, informed conversations regarding ionizing radiation are occurring between patients and providers; characterize public awareness of medical imaging procedures as sources of IR exposure; and investigate best practices in patientprovider communications. Methods. We developed and administered a 17-question survey to 303 adults at five locations across Chittenden County, Vermont, over a 6-week period in fall 2016. Descriptive and statistical analyses were conducted using SPSS. Results. The three age groups of respondents had different knowledge levels about ionizing radiation (p Conclusions/Recommendations. 1. A standard oral presentation for pre-imaging patient-provider communication, along with a written handout, be developed; 2. A section of the electronic medical record (also accessible through the patient portal) containing IR exposure be created for patients and physicians to track individuals\u27 information.https://scholarworks.uvm.edu/comphp_gallery/1249/thumbnail.jp

A study of patent thickets

Report analysing whether entry of UK enterprises into patenting in a technology area is affected by patent thickets in the technology area

Deep Exclusive Electroproduction of \u3ci\u3eπ\u3c/i\u3e\u3csup\u3e0\u3c/sup\u3e at High \u3ci\u3eQ\u3c/i\u3e\u3csup\u3e2\u3c/sup\u3e in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of B (0.36, 0.48, and 0.60) and Q2 (3.1 to 8.4  GeV2) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσT/dt+εdσL/dt, dσTT/dt, dσLT/dt, and dσLT′/dt are extracted as a function of the proton momentum transfer t−tmin. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon

Translating dosage compensation to trisomy 21

Down syndrome is the leading genetic cause of intellectual disabilities, occurring in 1 out of 700 live births. Given that Down syndrome is caused by an extra copy of chromosome 21 that involves over-expression of 400 genes across a whole chromosome, it precludes any possibility of a genetic therapy. Our lab has long studied the natural dosage compensation mechanism for X chromosome inactivation. To “dosage compensate” X-linked genes between females and males, the X-linked XIST gene produces a large non-coding RNA that silences one of the two X chromosomes in female cells. The initial motivation of this study was to translate the natural mechanisms of X chromosome inactivation into chromosome therapy for Down syndrome. Using genome editing with zinc finger nucleases, we have successfully inserted a large XIST transgene into Chromosome 21 in Down syndrome iPS cells, which results in chromosome-wide transcriptional silencing of the extra Chromosome 21. Remarkably, deficits in proliferation and neural growth are rapidly reversed upon silencing one chromosome 21. Successful trisomy silencing in vitro surmounts the major first step towards potential development of “chromosome therapy” for Down syndrome. The human iPSC-based trisomy correction system we established opens a unique opportunity to identify therapeutic targets and study transplantation therapies for Down syndrome

International patent families: from application strategies to statistical indicators

This paper provides an in-depth analysis of the characteristics of international patent families, including their domestic component. We exploit a relatively under-studied feature of patent families, namely the number of patents covering the same invention within a given jurisdiction. Using this information, we highlight common patterns in the structure of international patent families, which reflect both the patenting strategies of innovators and the peculiarities of the different patent systems. While the literature has extensively used family size, i.e. the number of countries in which a given invention is protected, as a measure of patent value, our results suggest that the number of patent filings in the priority country within a patent family as well as the timespan between the first and last fillings within a family are other insightful indicators of the value of patented innovations

Can lepton flavor violating interactions explain the atmospheric neutrino problem?

We investigate whether flavor changing neutrino interactions (FCNIs) can be sufficiently large to provide a viable solution to the atmospheric neutrino problem. Effective operators induced by heavy boson exchange that allow for flavor changing neutrino scattering off quarks or electrons are related by an $SU(2)_L$ rotation to operators that induce anomalous tau decays. Since $SU(2)_L$ violation is small for New Physics at or above the weak scale, one can use the upper bounds on lepton flavor violating tau decays or on lepton universality violation to put severe, model-independent bounds on the relevant non-standard neutrino interactions. Also $Z$-induced flavor changing neutral currents, due to heavy singlet neutrinos, are too small to be relevant for the atmospheric neutrino anomaly. We conclude that the FCNI solution to the atmospheric neutrino problem is ruled out.Comment: 16 pages, no figures, Late

Are Messages of R-parity Violating Supersymmetry Hidden within Top Quark Signals ?

In an R-parity nonconserving supersymmetric theory, the lighter stop can dominantly decay into $b\mu$ and $b\tau$ if R-parity breaking has to explain the neutrino mass and mixing pattern suggested by the data on atmospheric muon neutrinos. This should give rise to $dilepton+dijet$ and $single-lepton+jets$, signals resembling those of the top quark at the Fermilab Tevatron. One can thus constrain the stop parameter space using the current top search data, and similarly look for the first signals of supersymmetry at the upgraded runs of the Tevatron.Comment: 13 pages, RevTeX, 2 PS figures, uses epsfig.sty, few comments and references added, version to appear in Phys. Rev. Let