139 research outputs found
Higgs Boson Phenomenology in a Simple Model with Vector Resonances
In this paper we consider a simple scenario where the Higgs boson and two
vector resonances are supposed to arise from a new strong interacting sector.
We use the ATLAS measurements of the dijet spectrum to set limits on the masses
of the resonances. Additionally we compute the Higgs boson decay to two photons
and found, when compare to the Standard Model prediction, a small excess which
is compatible with ATLAS measurements. Finally we make prediction for
Higgs-strahlung processes for the LHC running at 14 TeV
Search for sterile neutrinos decaying into pions at the LHC
We study the possibility to observe sterile neutrinos with masses in the
range between 5 GeV and 20 GeV at the LHC, using the exclusive semileptonic
modes involving pions, namely W to lepton + N to n pions + lepton+lepton (n =
1, 2, 3). The two pion and three pion modes require extrapolations of form
factors to large time-like , which we do using vector dominance models as
well as light front holographic QCD, with remarkable agreement. This mass
region is difficult to explore with inclusive dilepton+dijet modes or trilepton
modes and impossible to explore in rare meson decays. While particle
identification is a real challenge in these modes, vertex displacement due to
the long living neutrino in the above mass range can greatly help reduce
backgrounds. Assuming a sample of W bosons at the end of the LHC Run 2,
these modes could discover a sterile neutrino in the above mass range or
improve the current bounds on the heavy-to-light lepton mixings by an order of
magnitude, . Moreover, by studying the equal
sign and opposite sign dileptons, the Majorana or Dirac character of the
sterile neutrino may be revealed.Comment: 18 pages, 4 double figure
Probing Neutrino Dirac Mass in Left-Right Symmetric Models at the LHC and Next Generation Colliders
We assess the sensitivity of the LHC, its high energy upgrade, and a
prospective 100 TeV hadronic collider to the Dirac Yukawa coupling of the heavy
neutrinos in left-right symmetric models (LRSMs). We focus specifically on the
trilepton final state in regions of parameter space yielding prompt decays of
the right-handed gauge bosons () and neutrinos (). In the minimal
LRSM, the Dirac Yukawa couplings are completely fixed in terms of the mass
matrices for the heavy and light neutrinos. In this case, the trilepton signal
provides a direct probe of the Dirac mass term for a fixed and
mass. We find that while it is possible to discover the at the LHC,
probing the Dirac Yukawa couplings will require a 100 TeV collider. We
also show that the observation of the trilepton signal at the LHC would
indicate the presence of a non-minimal LRSM scenario.Comment: 28 pages, 10 figures, references adde
Towards a Cosmological Hubble Diagram for Type II-P Supernovae
We present the first high-redshift Hubble diagram for Type II-P supernovae
(SNe II-P) based upon five events at redshift up to z~0.3. This diagram was
constructed using photometry from the Canada-France-Hawaii Telescope Supernova
Legacy Survey and absorption line spectroscopy from the Keck observatory. The
method used to measure distances to these supernovae is based on recent work by
Hamuy & Pinto (2002) and exploits a correlation between the absolute brightness
of SNe II-P and the expansion velocities derived from the minimum of the Fe II
516.9 nm P-Cygni feature observed during the plateau phases. We present three
refinements to this method which significantly improve the practicality of
measuring the distances of SNe II-P at cosmologically interesting redshifts.
These are an extinction correction measurement based on the V-I colors at day
50, a cross-correlation measurement for the expansion velocity and the ability
to extrapolate such velocities accurately over almost the entire plateau phase.
We apply this revised method to our dataset of high-redshift SNe II-P and find
that the resulting Hubble diagram has a scatter of only 0.26 magnitudes, thus
demonstrating the feasibility of measuring the expansion history, with present
facilities, using a method independent of that based upon supernovae of Type
Ia.Comment: 36 pages, 16 figures, accepted for publication in Ap
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
CSF Tau phosphorylation at Thr205 is associated with loss of white matter integrity in autosomal dominant Alzheimer disease
BACKGROUND: Hyperphosphorylation of tau leads to conformational changes that destabilize microtubules and hinder axonal transport in Alzheimer\u27s disease (AD). However, it remains unknown whether white matter (WM) decline due to AD is associated with specific Tau phosphorylation site(s).
METHODS: In autosomal dominant AD (ADAD) mutation carriers (MC) and non-carriers (NC) we compared cerebrospinal fluid (CSF) phosphorylation at tau sites (pT217, pT181, pS202, and pT205) and total tau with WM measures, as derived from diffusion tensor imaging (DTI), and cognition. A WM composite metric, derived from a principal component analysis, was used to identify spatial decline seen in ADAD.
RESULTS: The WM composite explained over 70% of the variance in MC. WM regions that strongly contributed to the spatial topography were located in callosal and cingulate regions. Loss of integrity within the WM composite was strongly associated with AD progression in MC as defined by the estimated years to onset (EYO) and cognitive decline. A linear regression demonstrated that amyloid, gray matter atrophy and phosphorylation at CSF tau site pT205 each uniquely explained a reduction in the WM composite within MC that was independent of vascular changes (white matter hyperintensities), and age. Hyperphosphorylation of CSF tau at other sites and total tau did not significantly predict WM composite loss.
CONCLUSIONS: We identified a site-specific relationship between CSF phosphorylated tau and WM decline within MC. The presence of both amyloid deposition and Tau phosphorylation at pT205 were associated with WM composite loss. These findings highlight a primary AD-specific mechanism for WM dysfunction that is tightly coupled to symptom manifestation and cognitive decline
Cerebrospinal fluid proteomics define the natural history of autosomal dominant Alzheimerâs disease
Alzheimerâs disease (AD) pathology develops many years before the onset of cognitive symptoms. Two pathological processesâaggregation of the amyloid-ÎČ (AÎČ) peptide into plaques and the microtubule protein tau into neurofibrillary tangles (NFTs)âare hallmarks of the disease. However, other pathological brain processes are thought to be key disease mediators of AÎČ plaque and NFT pathology. How these additional pathologies evolve over the course of the disease is currently unknown. Here we show that proteomic measurements in autosomal dominant AD cerebrospinal fluid (CSF) linked to brain protein coexpression can be used to characterize the evolution of AD pathology over a timescale spanning six decades. SMOC1 and SPON1 proteins associated with AÎČ plaques were elevated in AD CSF nearly 30 years before the onset of symptoms, followed by changes in synaptic proteins, metabolic proteins, axonal proteins, inflammatory proteins and finally decreases in neurosecretory proteins. The proteome discriminated mutation carriers from noncarriers before symptom onset as well or better than AÎČ and tau measures. Our results highlight the multifaceted landscape of AD pathophysiology and its temporal evolution. Such knowledge will be critical for developing precision therapeutic interventions and biomarkers for AD beyond those associated with AÎČ and tau.Fil: Johnson, Erik C. B.. University of Emory; Estados UnidosFil: Bian, Shijia. University of Emory; Estados UnidosFil: Haque, Rafi U.. University of Emory; Estados UnidosFil: Carter, E. Kathleen. University of Emory; Estados UnidosFil: Watson, Caroline M.. University of Emory; Estados UnidosFil: Gordon, Brian A.. Washington University in St. Louis; Estados UnidosFil: Ping, Lingyan. University of Emory; Estados UnidosFil: Duong, Duc M.. University of Emory; Estados UnidosFil: Epstein, Michael P.. University of Emory; Estados UnidosFil: McDade, Eric. Washington University in St. Louis; Estados UnidosFil: BarthĂ©lemy, Nicolas R.. Washington University in St. Louis; Estados UnidosFil: Karch, Celeste M.. Washington University in St. Louis; Estados UnidosFil: Xiong, Chengjie. Washington University in St. Louis; Estados UnidosFil: Cruchaga, Carlos. Washington University in St. Louis; Estados UnidosFil: Perrin, Richard J.. Washington University in St. Louis; Estados UnidosFil: Wingo, Aliza P.. Washington University in St. Louis; Estados UnidosFil: Wingo, Thomas S.. University of Emory; Estados UnidosFil: Chhatwal, Jasmeer P.. Harvard Medical School; Estados UnidosFil: Day, Gregory S.. University of Emory; Estados UnidosFil: Noble, James M.. Harvard Medical School; Estados UnidosFil: Berman, Sarah B.. Mayo Clinic; Estados UnidosFil: Martins, Ralph. Edith Cowan University; AustraliaFil: Graff Radford, Neill R.. Univeristy of Pittsburgh. School of Medicine; Estados Unidos. Mayo Clinic; Estados UnidosFil: Surace, Ezequiel Ignacio. FundaciĂłn para la Lucha Contra las Enfermedades NeurolĂłgicas de la Infancia. Instituto de Investigaciones NeurolĂłgicas "RaĂșl Carrea"; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Ortiz, Ana Luisa Sosa. Washington University in St. Louis; Estados UnidosFil: Daniels, Alisha. Washington University in St. Louis; Estados UnidosFil: Courtney, Laura. Washington University in St. Louis; Estados UnidosFil: Supnet Bell, Charlene. Washington University in St. Louis; Estados UnidosFil: Xu, Jinbin. No especifĂca;Fil: Ringman, John. No especifĂca
Insulin/IGF and Sex Hormone Axes in Human Endometrium and Associations with Endometrial Cancer Risk Factors
Given an ordered set of points and an ordered set of geometric objects in the plane, we are interested in finding a non-crossing matching between point-object pairs. In this paper, we address the algorithmic problem of determining whether a non-crossing matching exists between a given point-object pair. We show that when the objects we match the points to are finite point sets, the problem is NP-complete in general, and polynomial when the objects are on a line or when their size is at most 2. When the objects are line segments, we show that the problem is NP-complete in general, and polynomial when the segments form a convex polygon or are all on a line. Finally, for objects that are straight lines, we show that the problem of finding a min-max non-crossing matching is NP-complete. © 2012 Elsevier B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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