Renormalization analysis of intermittency in two coupled maps

The critical behavior for intermittency is studied in two coupled one-dimensional (1D) maps. We find two fixed maps of an approximate renormalization operator in the space of coupled maps. Each fixed map has a common relavant eigenvaule associated with the scaling of the control parameter of the uncoupled one-dimensional map. However, the relevant ``coupling eigenvalue'' associated with coupling perturbation varies depending on the fixed maps. These renormalization results are also confirmed for a linearly-coupled case.Comment: 11 pages, RevTeX, 2 eps figure

Ultra-stripped Type Ic supernovae from close binary evolution

Recent discoveries of weak and fast optical transients raise the question of their origin. We investigate the minimum ejecta mass associated with core-collapse supernovae (SNe) of Type Ic. We show that mass transfer from a helium star to a compact companion can produce an ultra-stripped core which undergoes iron core collapse and leads to an extremely fast and faint SN Ic. In this Letter, a detailed example is presented in which the pre-SN stellar mass is barely above the Chandrasekhar limit, resulting in the ejection of only ~0.05-0.20 M_sun of material and the formation of a low-mass neutron star. We compute synthetic light curves of this case and demonstrate that SN 2005ek could be explained by our model. We estimate that the fraction of such ultra-stripped to all SNe could be as high as 0.001-0.01. Finally, we argue that the second explosion in some double neutron star systems (for example, the double pulsar PSR J0737-3039B) was likely associated with an ultra-stripped SN Ic.Comment: ApJ Letters, in press, 6 pages, 5 figures (emulateapj style). Very minor changes to match printed version. Follow DOI link below for online published versio

Outcomes of psychological therapies for prisoners with mental health problems: a systematic review and meta-analysis

Objective: Prisoners worldwide have substantial mental health needs, but the efficacy of psychological therapy in prisons is unknown. We aimed to systematically review psychological therapies with mental health outcomes in prisoners and qualitatively summarize difficulties in conducting randomized clinical trials (RCTs). Method: We systematically identified RCTs of psychological therapies with mental health outcomes in prisoners (37 studies). Effect sizes were calculated and meta-analyzed. Eligible studies were assessed for quality. Subgroup and metaregression analyses were conducted to examine sources of between-study heterogeneity. Thematic analysis reviewed difficulties in conducting prison RCTs. Results: In 37 identified studies, psychological therapies showed a medium effect size (0.50, 95% CI [0.34, 0.66]) with high levels of heterogeneity with the most evidence for CBT and mindfulness-based trials. Studies that used no treatment (0.77, 95% CI [0.50, 1.03]) or waitlist controls (0.71, 95% CI [0.43, 1.00]) had larger effect sizes than those that had treatment-as-usual or other psychological therapies as controls (0.21, 95% CI [0.01, 0.41]). Effects were not sustained on follow-up at 3 and 6 months. No differences were found between group and individual therapy, or different treatment types. The use of a fidelity measure was associated with lower effect sizes. Qualitative analysis identified difficulties with follow-up and institutional constraints on scheduling and implementation of trials. Conclusions: CBT and mindfulness-based therapies are modestly effective in prisoners for depression and anxiety outcomes. In prisons with existing psychological therapies, more evidence is required before additional therapies can be recommended

New Measurements of 71^{71}Ge Decay: Impact on the Gallium Anomaly

A dedicated high-statistics measurement of the $^{71}$Ge half-life is found to be in accurate agreement with an accepted value of 11.43$\pm$0.03 d, eliminating a recently proposed route to bypass the "gallium anomaly" affecting several neutrino experiments. Our data also severely constrain the possibility of $^{71}$Ge decay to low-energy excited levels of the $^{71}$Ga daughter nucleus as a solution to this puzzle. Additional unpublished measurements of this decay are discussed. Following the incorporation of this new information, the gallium anomaly survives with high statistical significance.Comment: 3 pages, 2 figure

On the origin of microturbulence in hot stars

We present results from the first extensive study of convection zones in the envelopes of hot massive stars, which are caused by opacity peaks associated with iron and helium ionization. These convective regions can be located very close to the stellar surface. Recent observations of microturbulence in massive stars from the VLT-Flames survey are in good agreement with our predictions concerning the occurrence and the strength of sub-surface convection in hot stars. We argue further that convection close to the surface may trigger clumping at the base of the stellar wind of massive stars.Comment: to appear in Comm. in Astroseismology - Proceedings of the 38th LIAC/HELAS-ESTA/BAG, 200

Nano granular metallic Fe - oxygen deficient TiO2−δ_{2-\delta} composite films: A room temperature, highly carrier polarized magnetic semiconductor

Nano granular metallic iron (Fe) and titanium dioxide (TiO$_{2-\delta}$) were co-deposited on (100) lanthanum aluminate (LaAlO$_3$) substrates in a low oxygen chamber pressure using a pulsed laser ablation deposition (PLD) technique. The co-deposition of Fe and TiO$_2$ resulted in $\approx$ 10 nm metallic Fe spherical grains suspended within a TiO$_{2-\delta}$ matrix. The films show ferromagnetic behavior with a saturation magnetization of 3100 Gauss at room temperature. Our estimate of the saturation magnetization based on the size and distribution of the Fe spheres agreed well with the measured value. The film composite structure was characterized as p-type magnetic semiconductor at 300 K with a carrier density of the order of $10^{22} /{\rm cm^3}$. The hole carriers were excited at the interface between the nano granular Fe and TiO$_{2-\delta}$ matrix similar to holes excited in the metal/n-type semiconductor interface commonly observed in Metal-Oxide-Semiconductor (MOS) devices. From the large anomalous Hall effect directly observed in these films it follows that the holes at the interface were strongly spin polarized. Structure and magneto transport properties suggested that these PLD films have potential nano spintronics applications.Comment: 6 pages in Latex including 8 figure

Absence of ferromagnetism in Co and Mn substituted polycrystalline ZnO

We discuss the properties of semiconducting bulk ZnO when substituted with the magnetic transition metal ions Mn and Co, with substituent fraction ranging from $x$ = 0.02 to $x$ = 0.15. The magnetic properties were measured as a function of magnetic field and temperature and we find no evidence for magnetic ordering in these systems down to $T$ = 2 K. The magnetization can be fit by the sum of a Curie-Weiss term with a Weiss temperature of $\Theta\gg$100 K and a Curie term. We attribute this behavior to contributions from both \textit{t}M ions with \textit{t}M nearest neighbors and from isolated spins. This particular functional form for the susceptibility is used to explain why no ordering is observed in \textit{t}M substituted ZnO samples despite the large values of the Weiss temperature. We also discuss in detail the methods we used to minimize any impurity contributions to the magnetic signal.Comment: 6 pages, 4 figures (revised

Effective Action of QED in Electric Field Backgrounds II: Spatially Localized Fields

We find the Bogoliubov coefficient from the tunneling boundary condition on a charged particle coupled to a static electric field $E_0 sech^2 (z/L)$ and, using the regularization scheme in Phys. Rev. D 78, 105013 (2008), obtain the exact one-loop effective action in scalar and spinor QED. It is shown that the effective action satisfies the general relation between the vacuum persistence and the mean number of produced pairs. We advance an approximation method for general electric fields and show the duality between the space-dependent and time-dependent electric fields of the same form at the leading order of the effective actions.Comment: RevTex 7 pages, no figure; extension of arXiv:0807.2696 to space-dependent electric fields; new section added on approximate effective actions in general electric fields and conclusion shortened; references added; replaced by the version to be published in Phys. Rev.

Cosmic-Ray Proton and Helium Spectra from the First CREAM Flight

Cosmic-ray proton and helium spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass experiment flown for 42 days in Antarctica in the 2004-2005 austral summer season. High-energy cosmic-ray data were collected at an average altitude of ~38.5 km with an average atmospheric overburden of ~3.9 g cm$^{-2}$. Individual elements are clearly separated with a charge resolution of ~0.15 e (in charge units) and ~0.2 e for protons and helium nuclei, respectively. The measured spectra at the top of the atmosphere are represented by power laws with a spectral index of -2.66 $\pm$ 0.02 for protons from 2.5 TeV to 250 TeV and -2.58 $\pm$ 0.02 for helium nuclei from 630 GeV/nucleon to 63 TeV/nucleon. They are harder than previous measurements at a few tens of GeV/nucleon. The helium flux is higher than that expected from the extrapolation of the power law fitted to the lower-energy data. The relative abundance of protons to helium nuclei is 9.1 $\pm$ 0.5 for the range from 2.5 TeV/nucleon to 63 TeV/nucleon. This ratio is considerably smaller than the previous measurements at a few tens of GeV/nucleon.Comment: 20 pages, 4 figure