Primordial Bispectrum Information from CMB Polarization

After the precise observations of the Cosmic Microwave Background (CMB) anisotropy power spectrum, attention is now being focused on the higher order statistics of the CMB anisotropies. Since linear evolution preserves the statistical properties of the initial conditions, observed non-Gaussianity of the CMB will mirror primordial non-Gaussianity. Single field slow-roll inflation robustly predicts negligible non-Gaussianity so an indication of non-Gaussianity will suggest alternative scenarios need to be considered. In this paper we calculate the information on primordial non-Gaussianity encoded in the polarization of the CMB. After deriving the optimal weights for a cubic estimator we evaluate the Signal-to-Noise ratio of the estimator for WMAP, Planck and an ideal cosmic variance limited experiment. We find that when the experiment can observe CMB polarization with good sensitivity, the sensitivity to primordial non-Gaussianity increases by roughly a factor of two. We also test the weakly non-Gaussian assumption used to derive the optimal weight factor by calculating the degradation factor produced by the gravitational lensing induced connected four-point function. The physical scales in the radiative transfer functions are largely irrelevant for the constraints on the primordial non-Gaussianity. We show that the total (S/N)^2 is simply proportional to the number of observed pixels on the sky.Comment: To be submitted to PRD, 25 pages, 6 figure

Consistency relation for single scalar inflation

Single scalar field inflation with a generic, non-quadratic in derivatives, field Lagrangian is considered. It is shown that non-Gaussianity of curvature perturbations is characterized by two dimensionless amplitudes. One of these amplitudes can be expressed in terms of the usual inflationary observables -- the scalar power, the tensor power, and the tensor index. This consistency relation provides an observational test for the single scalar inflation.Comment: 6 page

S and D-wave phase shifts in isospin-2 pi pi scattering from lattice QCD

The isospin-2 pi pi system provides a useful testing ground for determining elastic hadron scattering parameters from finite-volume spectra obtained using lattice QCD computations. A reliable determination of the excited state spectrum of two pions in a cubic box follows from variational analysis of correlator matrices constructed using a large basis of operators. A general operator construction is presented which respects the symmetries of a multi-hadron system in flight. This is applied to the case of pi pi and allows for the determination of the scattering phase-shifts at a large number of kinematic points, in both S-wave and D-wave, within the elastic region. The technique is demonstrated with a calculation at a pion mass of 396 MeV, where the elastic scattering is found to be well described by a scattering length parameterisation.Comment: Tables of little-group CGCs in ancillary file; v2: minor changes to reflect published versio

Helicity operators for mesons in flight on the lattice

Motivated by the desire to construct meson-meson operators of definite relative momentum in order to study resonances in lattice QCD, we present a set of single-meson interpolating fields at non-zero momentum that respect the reduced symmetry of a cubic lattice in a finite cubic volume. These operators follow from the subduction of operators of definite helicity into irreducible representations of the appropriate little groups. We show their effectiveness in explicit computations where we find that the spectrum of states interpolated by these operators is close to diagonal in helicity, admitting a description in terms of single-meson states of identified J^{PC}. The variationally determined optimal superpositions of the operators for each state give rapid relaxation in Euclidean time to that state, ideal for the construction of meson-meson operators and for the evaluation of matrix elements at finite momentum.Comment: 25 pages, 14 figures; v2: minor changes to reflect journal versio

Excited state baryon spectroscopy from lattice QCD

We present a calculation of the Nucleon and Delta excited state spectrum on dynamical anisotropic clover lattices. A method for operator construction is introduced that allows for the reliable identification of the continuum spins of baryon states, overcoming the reduced symmetry of the cubic lattice. Using this method, we are able to determine a spectrum of single-particle states for spins up to and including J = 7/2, of both parities, the first time this has been achieved in a lattice calculation. We find a spectrum of states identifiable as admixtures of SU(6) x O(3) representations and a counting of levels that is consistent with the non-relativistic $qqq$ constituent quark model. This dense spectrum is incompatible with quark-diquark model solutions to the "missing resonance problem" and shows no signs of parity doubling of states.Comment: 29 pages, 18 figure

The role of copper in disulfiram-induced toxicity and radiosensitisation of cancer cells.

Abstract Disulfiram has been used for several decades in the treatment of alcoholism. It now shows promise as an anti-cancer drug and radiosensitizer. Proposed mechanisms of action include the induction of oxidative stress and inhibition of proteasome activity. Our purpose was to determine the potential of disulfiram to enhance the anti-tumor efficacy of external beam -irradiation and 131I-metaiodobenzylguanidine (131I-MIBG), a radiopharmaceutical used for the therapy of neuroendocrine tumors. Methods: The role of copper in disulfiram-induced toxicity was investigated by clonogenic assay after treatment of human SK-N-BE(2c) neuroblastoma and UVW/NAT glioma cells. Synergistic interaction between disulfiram and radiotherapy was evaluated by combination index analysis. Tumor growth delay was determined in vitro using multicellular tumor spheroids and in vivo using human tumor xenografts in athymic mice. Results: Escalating disulfiram dosage caused a biphasic reduction in the surviving fraction of clonogens. Clonogenic cell kill after treatment with disulfiram concentrations less than 4 M was copper-dependent, whereas cytotoxicity at concentrations greater than 10 M was caused by oxidative stress. The cytotoxic effect of disulfiram was maximal when administered with equimolar copper. Likewise, disulfiram’s radiosensitization of tumor cells was copper-dependent. Furthermore, disulfiram treatment enhanced the toxicity of 131I-MIBG to spheroids and xenografts expressing the noradrenaline transporter. Conclusions: The results demonstrate that (i) the cytotoxicity of disulfiram was copper-dependent; (ii) molar excess of disulfiram relative to copper resulted in attenuation of disulfiram-mediated cytotoxicity; (iii) copper was required for the radiosensitizing activity of disulfiram and (iv) copper-complexed disulfiram enhanced the efficacy not only of external beam radiation but also of targeted radionuclide therapy in the form of 131I-MIBG. Therefore disulfiram may have anti-cancer potential in combination with radiotherapy

Model-independent constraints on contact interactions from LEP2 data analysis

We derive model-independent constraints on four-fermion contact interaction-type dynamics from the published preliminary LEP2 experimental data on e^+e^- annihilation into \mu^+\mu^- and \tau^+\tau^- pairs, measured at different energies between 130 and 207 GeV. The basic observables are chosen to be the total cross section and the forward-backward asymmetry, and the analysis realistically takes into account data uncertainties and correlations among measurements at the various energies. The combination of data from different energy points plays an important role in the determination of regions allowed for the contact interaction coupling constants. In contrast to the more common one-parameter analyses, we only obtain constraints on pairs of parameters rather than limits on individual ones.Comment: 13 pages, LaTeX, including figures. v2: Included discussion of tau data, version to appear in EPJ

Imprint of Inhomogeneous Reionization on the Power Spectrum of Galaxy Surveys at High Redshifts

We consider the effects of inhomogeneous reionization on the distribution of galaxies at high redshifts. Modulation of the formation process of the ionizing sources by large scale density modes makes reionization inhomogeneous and introduces a spread to the reionization times of different regions with the same size. After sources photo-ionize and heat these regions to a temperature \ga 10^4K at different times, their temperatures evolve as the ionized intergalactic medium (IGM) expands. The varying IGM temperature makes the minimum mass of galaxies spatially non-uniform with a fluctuation amplitude that increases towards small scales. These scale-dependent fluctuations modify the shape of the power spectrum of low-mass galaxies at high redshifts in a way that depends on the history of reionization. The resulting distortion of the primordial power spectrum is significantly larger than changes associated with uncertainties in the inflationary parameters, such as the spectral index of the scalar power spectrum or the running of the spectral index. Future surveys of high-redshift galaxies will offer a new probe of the thermal history of the IGM but might have a more limited scope in constraining inflation.Comment: 8 pages, 5 figures, replaced to match version accepted by Ap

Review of Student Support Services in USA

The review deals with the issues of organization of a socio-psychological support service for students. The realization of priority projects aimed to attract foreign students to Russian higher education institutions sets the task to design socio-psychological support models for these students. In view of this, it is important to study the experience of organization of such student support abroad. This review describes the approaches to the organization of student support services in the USA. The article provides a detailed description of the TRIO programs which presuppose discretionary and competitive grants for higher education institutions. Funds are awarded to institutions of higher education to provide opportunities for academic development, assist students with basic college requirements, and to motivate students toward the successful completion of their post-secondary education. TRIO projects include: academic tutoring, services in the field of education and counseling to improve the financial and economic literacy of participants, individual counseling for young people who are officially registered as homeless during vacation or live in a foster family. The review emphasizes the importance of development of the student support system in Russian education institutions. The authors define the notion of “social student support” in the following way: in a broad context, as a unity of positive interventions of the closest social environment, and in a narrow context, as direct assistance in stressful situations. The following kinds of social student support have been analyzed: information support, status support, instrumental support, emotional support and diffuse support. Social support should meet the following demands: to be protected, to be recognized, to belong to a community, and to achieve self-realization. The review explores the mediating effect of support on various levels: on the physiological level (lessening of anxiety); on the level of motivation sphere (perception of other people’s attention; it increases students’ inner motivation); on the level of affective sphere (creation of the feeling of security and safety); on the level of cognitive sphere (acquisition of new points of view, alternative context while perceiving stressful situation); on the level of behavior (new ways of problem solving, alternative behavior models, etc.); on the level of personality (encouraging self-respect, provision of emotional support, enhancing the feelings of inner control and competence, critical for inner resources mobilization in stressful situations).Обзор посвящен рассмотрению вопросов организации службы социально-психологической поддержки студентов. Реализация приоритетных проектов по привлечению иностранных студентов в российские вузы ставит задачу разработки моделей социально-психологического сопровождения этих обучающихся. В этой связи важно изучить опыт организации такого сопровождения студентов в других странах. В обзоре представлены подходы к организации служб поддержки студентов в США. Подробно раскрывается программа TRIO, которая предоставляет дискреционные и конкурентные гранты высшим учебным заведениям для достижения студентами академических успехов, оказания им помощи в выполнении основных требований колледжа, поддержку мотивации и психического здоровья студентов для успешного завершения обучения. Проекты программы TRIO включают: академическое наставничество, услуги в области образования и консультирования для улучшения финансовой и экономической грамотности, индивидуальное консультирование для зарегистрированной молодежи, которая во время каникул имеет бездомный статус или проживает в приемной семье. Подчеркивается важность развития системы поддержки в российских образовательных учреждениях. Раскрывается понятие «социальная поддержка студентов»: в широком контексте, как совокупность положительных влияний ближайшей социальной среды, помогающей успешной интеграции человека в системе социальных взаимоотношений, а также в узком контексте, как прямая помощь в стрессовых ситуациях. Проанализированы виды социальной поддержки студентам: информационная, статусная, инструментальная, эмоциональная, диффузная. Раскрыты потребности, которые удовлетворяет социальная поддержка: быть защищенным, признанным, принадлежать общности, иметь возможности самореализации. Проанализировано опосредующее влияние поддержки на различных уровнях: на физиологическом уровне (уменьшение тревожности); на уровне мотивационной сферы (восприятие внешнего внимания, повышает внутреннюю мотивацию студентов); на уровне аффективной сферы (создание чувства защищенности, безопасности); на уровне когнитивной сферы (усвоение новых точек зрения, альтернативный контекст при восприятии стрессовой ситуации); на уровне поведения (новые способы решения проблем, предоставление альтернативных моделей поведения и т. д.); на личностном уровне (поддержка самоуважения, предоставление эмоциональной опоры, поддержка чувств внутреннего контроля, компетентности, имеющие большое значение для мобилизации внутренних ресурсов в стрессовых ситуациях)