Reduced Density-Matrix Functional Theory: correlation and spectroscopy

In this work we explore the performance of approximations to electron correlation in reduced density-matrix functional theory (RDMFT) and of approximations to the observables calculated within this theory. Our analysis focuses on the calculation of total energies, occupation numbers, removal/addition energies, and spectral functions. We use the exactly solvable Hubbard molecule at 1/4 and 1/2 filling as test systems. This allows us to analyze the underlying physics and to elucidate the origin of the observed trends. For comparison we also report the results of the $GW$ approximation, where the self-energy functional is approximated, but no further hypothesis are made concerning the approximations of the observables. In particular we focus on the atomic limit, where the two sites of the molecule are pulled apart and electrons localize on either site with equal probability, unless a small perturbation is present: this is the regime of strong electron correlation. In this limit, using the Hubbard molecule at 1/2 filling with or without a spin-symmetry-broken ground state, allows us to explore how degeneracies and spin-symmetry breaking are treated in RDMFT. We find that, within the used approximations, neither in RDMFT nor in $GW$ the signature of strong correlation are present in the spin-singlet ground state, whereas both give the exact result for the spin-symmetry broken case. Moreover we show how the spectroscopic properties change from one spin structure to the other. Our findings can be generalized to other situations, which allows us to make connections to real materials and experiment

Photoemission Spectra from Reduced Density Matrices: the Band Gap in Strongly Correlated Systems

We present a method for the calculation of photoemission spectra in terms of reduced density matrices. We start from the spectral representation of the one-body Green's function G, whose imaginary part is related to photoemission spectra, and we introduce a frequency-dependent effective energy that accounts for all the poles of G. Simple approximations to this effective energy give accurate spectra in model systems in the weak as well as strong correlation regime. In real systems reduced density matrices can be obtained from reduced density-matrix functional theory. Here we use this approach to calculate the photoemission spectrum of bulk NiO: our method yields a qualitatively correct picture both in the antiferromagnetic and paramagnetic phases, contrary to mean-field methods, in which the paramagnet is a metal

Relationship of family involvement and functioning among mentally ill adults

The purposes of the present study were to find a relationship between family/caregiver involvement in treatment of mentally ill adults that they care for and clients\u27 overall Axis IV and V assessments. Support and education groups were held at Family Service in New Jersey over a six-month period. The population (n=12) came from the Hattie Tallie program at Family Service. These clients and their family members/social supports and caregivers attended meetings for six months to gain education and to support each other in dealing with clients\u27 treatment. Global Assessment of Functioning scores (Axis V) and Severity of stressors (Axis IV) were taken before these groups began and again at the completion of the six months. Correlation analysis revealed an overall maintenance of these scores throughout the six months. Research on family involvement and education for caregivers was discussed

Surfaces with surjective endomorphisms of any given degree

We present a complete classification of complex projective surfaces X with nontrivial self-maps (i.e. surjective morphisms f:X→X which are not isomorphisms) of any given degree. The starting point of our classification are results contained in Fujimoto and Nakayama that provide a list of surfaces that admit at least one nontrivial self-map. We then proceed by a case by case analysis that blends geometrical and arithmetical arguments in order to exclude that certain prime numbers appear as degrees of nontrivial self-maps of certain surfaces

Indian nurses in Italy: a qualitative study of their professional and social integration

AIMS AND OBJECTIVES: To investigate the lived subjective experiences of immigrant Indian nurses in Italy and specifically their professional and social integration. BACKGROUND: To study the worldwide, nursing flux is a health priority in the globalised world. The growth in migration trends among nurses, not only from Philippines or India, has proliferated in recent years. The research on nurses' mobility for Southern European countries is underexplored, and in Italy, the out-migration flows of Indian nurses were never analysed. DESIGN: Qualitative methodological approach. METHODS: Semi-structured interviews (n = 20) were completed with Indian clinical nurses working in Italy for more than one year mainly in private organisations. A purposive sampling technique was used for recruitment. The data were then content-analysed using an inductive method. RESULTS: The findings were categorised into four themes: (1) aspects of professional integration and working experience, (2) intra- and interprofessional relationships and perceptions of the IPASVI Regulatory Nursing Board, (3) initial nursing education and continuous professional development and (4) perceptions of social integration. CONCLUSION: The results show that for Indian nurses in Italy emigration is important to gain opportunities to expand economic and social privileges as well as escape from historical assumptions of stigma associated with nursing work, especially for women. However, these conclusions have to be seen in wider socio-cultural complexities that are at the basis of transnational fluxes (Prescott & Nichter ). RELEVANCE TO CLINICAL PRACTICE: The research offers an insight into the complicated reasons for Indian nurses out-migration to Italy. Without comprehending the interwoven textures of the political and social relations that are continually constructed and re-constructed among different nations, it is difficult to understand nurses out-migration and consequently have a better and safer collaborative teamwork in the host countries

Effectiveness of Interventions to Increase Screening for Breast, Cervical, and Colorectal Cancers Nine Updated Systematic Reviews for the Guide to Community Preventive Services

Context: Screening reduces mortality from breast, cervical, and colorectal cancers. The Guide to Community Preventive Services previously conducted systematic reviews on the effectiveness of 11 interventions to increase screening for these cancers. This article presents results of updated systematic reviews for nine of these interventions. Evidence acquisition: Five databases were searched for studies published during January 2004–October 2008. Studies had to (1) be a primary investigation of one or more intervention category; (2) be conducted in a country with a high-income economy; (3) provide information on at least one cancer screening outcome of interest; and (4) include screening use prior to intervention implementation or a concurrent group unexposed to the intervention category of interest. Forty-fıve studies were included in the reviews. Evidence synthesis: Recommendations were added for one-on-one education to increase screening with fecal occult blood testing (FOBT) and group education to increase mammography screening. Strength of evidence for client reminder interventions to increase FOBT screening was upgraded from suffıcient to strong. Previous fındings and recommendations for reducing out-of-pocket costs (breast cancer screening); provider assessment and feedback (breast, cervical, and FOBT screening); one-on-one education and client reminders (breast and cervical cancer screening); and reducing structural barriers (breast cancer and FOBT screening) were reaffırmed or unchanged. Evidence remains insuffıcient t

Speed limit to the Abrikosov lattice in mesoscopic superconductors

We study the instability of the superconducting state in a mesoscopic geometry for the low pinning material Mo$_3$Ge characterized by a large Ginzburg-Landau parameter. We observe that in the current driven switching to the normal state from a nonlinear region of the Abrikosov flux flow, the mean critical vortex velocity reaches a limiting maximum velocity as a function of the applied magnetic field. Based on time dependent Ginzburg-Landau simulations we argue that the observed behavior is due to the high velocity vortex dynamics confined on a mesoscopic scale. We build up a general phase diagram which includes all possible dynamic configurations of Abrikosov lattice in a mesoscopic superconductor.Comment: 7 pages, 6 figure