Substance P regulates puberty onset and fertility in the female mouse

Puberty is a tightly regulated process that leads to reproductive capacity. Kiss1 neurons are crucial in this process by stimulating GnRH, yet how Kiss1 neurons are regulated remains unknown. Substance P (SP), an important neuropeptide in pain perception, induces gonadotropin release in adult mice in a kisspeptin-dependent manner. Here, we assessed whether SP, through binding to its receptor NK1R (neurokinin 1 receptor), participates in the timing of puberty onset and fertility in the mouse. We observed that 1) selective NK1R agonists induce gonadotropin release in prepubertal females; 2) the expression of Tac1 (encoding SP) and Tacr1 (NK1R) in the arcuate nucleus is maximal before puberty, suggesting increased SP tone; 3) repeated exposure to NK1R agonists prepubertally advances puberty onset; and 4) female Tac1-/- mice display delayed puberty; moreover, 5) SP deficiency leads to subfertility in females, showing fewer corpora lutea and antral follicles and leading to decreased litter size. Thus, our findings support a role for SP in the stimulation of gonadotropins before puberty, acting via Kiss1 neurons to stimulate GnRH release, and its involvement in the attainment of full reproductive capabilities in female mice. Copyright © 2015 by the Endocrine Society

Derivation and assessment of risk prediction models using case-cohort data

Background Case-cohort studies are increasingly used to quantify the association of novel factors with disease risk. Conventional measures of predictive ability need modification for this design. We show how Harrell’s C-index, Royston’s D, and the category-based and continuous versions of the net reclassification index (NRI) can be adapted. Methods We simulated full cohort and case-cohort data, with sampling fractions ranging from 1% to 90%, using covariates from a cohort study of coronary heart disease, and two incidence rates. We then compared the accuracy and precision of the proposed risk prediction metrics. Results The C-index and D must be weighted in order to obtain unbiased results. The NRI does not need modification, provided that the relevant non-subcohort cases are excluded from the calculation. The empirical standard errors across simulations were consistent with analytical standard errors for the C-index and D but not for the NRI. Good relative efficiency of the prediction metrics was observed in our examples, provided the sampling fraction was above 40% for the C-index, 60% for D, or 30% for the NRI. Stata code is made available. Conclusions Case-cohort designs can be used to provide unbiased estimates of the C-index, D measure and NRI

A Matrix Model for AdS2

A matrix quantum mechanics with potential $V={q^2 \over r^2}$ and an SL(2,R) conformal symmetry is conjectured to be dual to two-dimensional type 0A string theory on AdS$_2$ with $q$ units of RR flux.Comment: 12 page

Flux Backgrounds in 2D String Theory

We study RR flux backgrounds in two dimensional type 0 string theories. In particular, we study the relation between the 0A matrix model and the extremal black hole in two dimensions. Using T-duality we find a dual flux background in type 0B theory and propose its matrix model description. When the Fermi level is set to zero this system remains weakly coupled and exhibits a larger symmetry related to the structure of flux vacua. Finally, we construct a two dimensional type IIB background as an orbifold of the 0B background.Comment: Harvmac, 40 pages, 6 figs, minor changes, references adde

Magnetic structure of CeRhIn_5 as a function of pressure and temperature

We report magnetic neutron-diffraction and electrical resistivity studies on single crystals of the heavy-fermion antiferromagnet CeRhIn$_{5}$ at pressures up to 2.3 GPa. These experiments show that the staggered moment of Ce and the incommensurate magnetic structure change weakly with applied pressure up to 1.63 GPa, where resistivity, specific heat and NQR measurements confirm the presence of bulk superconductivity. This work places new constraints on an interpretation of the relationship between antiferromagnetism and unconventional superconductivity in CeRhIn$_{5}$.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

A spinor approach to Walker geometry

A four-dimensional Walker geometry is a four-dimensional manifold M with a neutral metric g and a parallel distribution of totally null two-planes. This distribution has a natural characterization as a projective spinor field subject to a certain constraint. Spinors therefore provide a natural tool for studying Walker geometry, which we exploit to draw together several themes in recent explicit studies of Walker geometry and in other work of Dunajski (2002) and Plebanski (1975) in which Walker geometry is implicit. In addition to studying local Walker geometry, we address a global question raised by the use of spinors.Comment: 41 pages. Typos which persisted into published version corrected, notably at (2.15

Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure

Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV

A search for pair-production of supersymmetric particles under the assumption that R-parity is violated via a dominant LQDbar coupling has been performed using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV. The observed candidate events in the data are in agreement with the Standard Model expectation. This result is translated into lower limits on the masses of charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81 GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the 95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure

Search for Doubly-Charged Higgs Boson Production at HERA

A search for the single production of doubly-charged Higgs bosons H^{\pm \pm} in ep collisions is presented. The signal is searched for via the Higgs decays into a high mass pair of same charge leptons, one of them being an electron. The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment at HERA. No evidence for doubly-charged Higgs production is observed and mass dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only decays into an electron and a muon via a coupling of electromagnetic strength h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3, masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl