Proximity Effect in Nb/Au/CoFe Trilayers

We have investigated the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au and CoFe thicknesses. Without the CoFe layer the superconducting critical temperatures of Nb/Au bilayers as a function of Au thickness follow the well-known proximity effect between a superconductor and a normal metal. The superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au thickness exhibit a rapid initial increase in the small Au thickness region and increase slowly to a limiting value above this region, accompanied by a small oscillation of Tc. On the other hand, the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of CoFe thickness show non-monotonic behavior with a shallow dip feature. We analyzed the Tc behavior in terms of Usadel formalism and found that most features are consistent with the theory, although the small oscillation of Tc as a function of the Au thickness cannot be accounted for. We have also found quantitative values for the two interfaces: Nb/Au and Au/CoFe.Comment: 25 pages, 6 figure

Effects of Electron Correlations on Hofstadter Spectrum

By allowing interactions between electrons, a new Harper's equation is derived to examine the effects of electron correlations on the Hofstadter energy spectra. It is shown that the structure of the Hofstadter butterfly ofr the system of correlated electrons is modified only in the band gaps and the band widths, but not in the characteristics of self-similarity and the Cantor set.Comment: 13 pages, 5 Postscript figure

A novel route to a finite center-of-mass momentum pairing state; current driven FFLO state

The previously studied Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is stabilized by a magnetic field via the Zeeman coupling in spin-singlet superconductors. Here we suggest a novel route to achieve non-zero center-of-mass momentum pairing states in superconductors with Fermi surface nesting. We investigate two-dimensional superconductors under a uniform external current, which leads to a finite pair-momentum of ${\bf q}_{e}$. We find that an FFLO state with a spontaneous pair-momentum of ${\bf q}_{s}$ is stabilized above a certain critical current which depends on the direction of the external current. A finite ${\bf q}_s$ arises in order to make the total pair-momentum of ${\bf q}_t(={\bf q}_s + {\bf q}_e)$ perpendicular to the nesting vector, which lowers the free energy of the FFLO state, as compared to the superconducting and normal states. We also suggest experimental signatures of the FFLO state.Comment: 4 pages, 5 figure

Effects of Childhood Trauma on the Psychological Distress of Black Homeless Youth: The Moderating Role of Social Support

Youth homelessness is a growing issue in the United States. Black homeless youth are a unique subgroup to be studied because these youth must simultaneously manage stressors that accompany racial minority and homeless statuses during critical stages of development. Using data from the Atlanta Youth Count Needs Assessment, this thesis explores the impact of childhood trauma on psychological distress of Black homeless youth (N=556). In addition, this thesis examines whether the relationship between childhood trauma and psychological distress is conditioned by the level of social support reported by Black homeless youth. Results show that childhood trauma experienced by Black homeless youth is associated with higher levels of psychological distress. Although greater social support is linked to lower levels of psychological distress, social support does not moderate the link between childhood trauma and psychological distress. These findings are intended to inform health policy and resource options for Black homeless youth

Groundwater for People and the Environment: A Globally Threatened Resource

The intensity of global groundwater use rose from 124 m3 per capita in 1950 to 152 m3 in 2021, for a 22.6% rise in the annual per capita use. This rise in global per capita water use reflects rising consumption patterns. The global use of groundwater, which provides between 21% and 30% of the total freshwater annual consumption, will continue to expand due to the sustained population growth projected through most of the 21st century and the important role that groundwater plays in the water-food-energy nexus. The rise in groundwater use, on the other hand, has inflicted adverse impacts in many aquifers, such as land subsidence, sea water intrusion, stream depletion, and deterioration of groundwater-dependent ecosystems, groundwater-quality degradation, and aridification. This paper projects global groundwater use between 2025 and 2050. The projected global annual groundwater withdrawal in 2050 is 1535 km3 (1 km3 = 109 m3 = 810,713 acre-feet). The projected global groundwater depletion, that is, the excess of withdrawal over recharge, in 2050 equals 887 km3, which is about 61% larger than in 2021. This projection signals probable exacerbation of adverse groundwater-withdrawal impacts, which are worsened by climatic trends and the environmental requirement of groundwater flow unless concerted national and international efforts achieve groundwater sustainability

Nonequilibrium effects due to charge fluctuations in intrinsic Josephson systems

Nonequilibrium effects in layered superconductors forming a stack of intrinsic Josephson junctions are investigated. We discuss two basic nonequilibrium effects caused by charge fluctuations on the superconducting layers: a) the shift of the chemical potential of the condensate and b) charge imbalance of quasi-particles, and study their influence on IV-curves and the position of Shapiro steps.Comment: 17 pages, 2 figures, revised version slightly shortene

The organisational and human resource challenges facing primary care trusts : protocol of a multiple case study

BACKGROUND: The study is designed to assess the organisational and human resource challenges faced by Primary Care Trusts (PCTs). Its objectives are to: specify the organisational and human resources challenges faced by PCTs in fulfilling the roles envisaged in government and local policy; examine how PCTs are addressing these challenges, in particular, to describe the organisational forms they have adopted, and the OD/HR strategies and initiatives they have planned or in place; assess how effective these structures, strategies and initiatives have been in enabling the PCTs to meet the organisational and human resources challenges they face; identify the factors, both internal to the PCT and in the wider health community, which have contributed to the success or failure of different structures, strategies and initiatives. METHODS: The study will be undertaken in three stages. In Stage 1 the key literature on public sector and NHS organisational development and human resources management will be reviewed, and discussions will be held with key researchers and policy makers working in this area. Stage 2 will focus on detailed case studies in six PCTs designed to examine the organisational and human resources challenges they face. Data will be collected using semi-structured interviews, group discussion, site visits, observation of key meetings and examination of local documentation. The findings from the case study PCTs will be cross checked with a Reference Group of up to 20 other PCG/Ts, and key officers working in organisational development or primary care at local, regional and national level. In Stage 3 analysis of findings from the preparatory work, the case studies and the feedback from the Reference Group will be used to identify practical lessons for PCTs, key messages for policy makers, and contributions to further theoretical development

Quality care in vesico-vaginal obstetric fistula: case series report from the regional hospital of Maroua-Cameroon

The World Health Organization (WHO) proposes a successful closure rate for first repair of vesico-vaginal obstetric fistula to be at 85% in each facility, with the continence achievement among the closed cases at 90 %. We are reporting the vesico-vaginal obstetric fistula outcome at the provincial hospital of Maroua- Cameroon from 2005 to August 2007. Among the overall 32 patients with vesico-vaginal fistula operated, 25 patients were at their first operation. The complete closure of vesico-vaginal fistula (VVF) was 23/25 (92%) and among the 23 patients with complete closure 17(74%) had good continence. When we consider only the 25 patients who were at their first operation, the overall closure of VVF was 23/25 (92%) and among them 17/23 (74%) were continent. Large lesion, bladder neck lesions, vaginal adherence and rigid margin are associated with failure/incontinence. These factors must be taken into consideration when preparing patients for surgery or when assigning them to a surgeon within the surgical team

Static Charge Coupling of Intrinsic Josephson Junction

A microscopic theory for the coupling of intrinsic Josephson oscillations due to charge fluctuations on the quasi two-dimensional superconducting layers is presented. Thereby in close analogy to the normal state the effect of the scalar potential on the transport current is taken into account consistently. The dispersion of collective modes is derived and an estimate of the coupling constant is given. It is shown that the correct treatment of the quasiparticle current is essential in order to get the correct position of Shapiro steps. In this case the influence of the coupling on dc-properties like the $I-V$-curve is negligible.Comment: 6 pages latex, 5 figures, espcrc2.sty, Invited Contribution to "2nd International Symposiom on Intrinsic Josephson Effects and Plasma Oscillations in High-TC Superconductors", 22-24 August, Sendai, Japan, to be published in Physica