Runaway evaporation for optically dressed atoms

Forced evaporative cooling in a far-off-resonance optical dipole trap is proved to be an efficient method to produce fermionic- or bosonic-degenerated gases. However in most of the experiences, the reduction of the potential height occurs with a diminution of the collision elastic rate. Taking advantage of a long-living excited state, like in two-electron atoms, I propose a new scheme, based on an optical knife, where the forced evaporation can be driven independently of the trap confinement. In this context, the runaway regime might be achieved leading to a substantial improvement of the cooling efficiency. The comparison with the different methods for forced evaporation is discussed in the presence or not of three-body recombination losses

Numerical modeling of collisional dynamics of Sr in an optical dipole trap

We describe a model of inelastic and elastic collisional dynamics of atoms in an optical dipole trap that utilizes numerical evaluation of statistical mechanical quantities and numerical solution of equations for the evolution of number and temperature of trapped atoms. It can be used for traps that possess little spatial symmetry and when the ratio of trap depth to sample temperature is relatively small. We compare simulation results with experiments on Sr88 and Sr84, which have well-characterized collisional properties

Tubular structures of GaS

In this Brief Report we demonstrate, using density-functional tight-binding theory, that gallium sulfide (GaS) tubular nanostructures are stable and energetically viable. The GaS-based nanotubes have a semiconducting direct gap which grows towards the value of two-dimensional hexagonal GaS sheet and is in contrast to carbon nanotubes largely independent of chirality. We further report on the mechanical properties of the GaS-based nanotubes

11^{11}B NMR study of pure and lightly carbon doped MgB2_2 superconductors

We report a $^{11}$B NMR line shape and spin-lattice relaxation rate ($1/(T_1T)$) study of pure and lightly carbon doped MgB$_{2-x}$C$_{x}$ for $x=0$, 0.02, and 0.04, in the vortex state and in magnetic field of 23.5 kOe. We show that while pure MgB$_2$ exhibits the magnetic field distribution from superposition of the normal and the Abrikosov state, slight replacement of boron with carbon unveils the magnetic field distribution of the pure Abrikosov state. This indicates a considerable increase of $H_{c2}^c$ with carbon doping with respect to pure MgB$_2$. The spin-lattice relaxation rate $1/(T_1T)$ demonstrates clearly the presence of a coherence peak right below $T_c$ in pure MgB$_2$, followed by a typical BCS decrease on cooling. However, at temperatures lower than $\approx 10$K strong deviation from the BCS behavior is observed, probably from residual contribution of the vortex dynamics. In the carbon doped systems both the coherence peak and the BCS temperature dependence of $1/(T_1T)$ weaken, an effect attributed to the gradual shrinking of the $\sigma$ hole cylinders of the Fermi surface with electron doping.Comment: 8 pages, 6 figures, submitted to Phys. Rev.

Adult attachment styles and the psychological response to infant bereavement

Background: Based on Bowlby's attachment theory, Bartholomew proposed a four-category attachment typology by which individuals judged themselves and adult relationships. This explanatory model has since been used to help explain the risk of psychiatric comorbidity. Objective: The current study aimed to identify attachment typologies based on Bartholomew's attachment styles in a sample of bereaved parents on dimensions of closeness/dependency and anxiety. In addition, it sought to assess the relationship between the resultant attachment typology with a range of psychological trauma variables. Method: The current study was based on a sample of 445 bereaved parents who had experienced either peri- or post-natal death of an infant. Adult attachment was assessed using the Revised Adult Attachment Scale (RAAS) while reaction to trauma was assessed using the Trauma Symptom Checklist (TSC). A latent profile analysis was conducted on scores from the RAAS closeness/dependency and anxiety subscales to ascertain if there were underlying homogeneous attachment classes. Emergent classes were used to determine if these were significantly different in terms of mean scores on TSC scales. Results: A four-class solution was considered the optimal based on fit statistics and interpretability of the results. Classes were labelled “Fearful,” “Preoccupied,” “Dismissing,” and “Secure.” Females were almost eight times more likely than males to be members of the fearful attachment class. This class evidenced the highest scores across all TSC scales while the secure class showed the lowest scores. Conclusions: The results are consistent with Bartholomew's four-category attachment styles with classes representing secure, fearful, preoccupied, and dismissing types. While the loss of an infant is a devastating experience for any parent, securely attached individuals showed the lowest levels of psychopathology compared to fearful, preoccupied, or dismissing attachment styles. This may suggest that a secure attachment style is protective against trauma-related psychological distress

Brown and black in white: The social adjustment and academic performance of Chicano and black students in a predominately white university

This article explores the academic and social experiences of Chicago and black students at UCLA. The analysis proceeds by examining differences in social backgrounds, high school and college experiences, and explores the relationship between these factors and college adjustment and achievement (GPA). Drawing upon recent theory on class reproduction and schooling we show particular concern with the role of social class in explaining differential outcomes. The findings indicate that blacks are more likely than Chicanos to feel alienated and perform poorly, and that social class makes no difference in these outcomes for blacks. However, middle class Chicanos perform better and are better adjusted than working class Chicanos. We discuss our findings in the light of theories of class reproduction, cultural capital, and racial signaling, suggesting that theories of reproduction must acknowledge the role of race in unequal school outcomes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43870/1/11256_2005_Article_BF01141631.pd

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems

NME5 frameshift variant in Alaskan Malamutes with primary ciliary dyskinesia

Author summary Motile cilia are required for clearing mucous, infectious agents and inhaled dust from the airways. Primary ciliary dyskinesia (PCD) is a hereditary defect of motile cilia. Clinical findings may include recurrent airway infections, fertility problems, and sometimes hydrocephalus. We analyzed an Alaskan Malamute family, in which two out of six puppies were affected by an autosomal recessive form of PCD. Whole genome sequencing of an affected dog identified a one base pair deletion in the NME5 gene, c.43delA, leading to an early frame-shift and premature stop codon. Later in the study, we became aware of a previously published Alaskan Malamute with PCD involving respiratory infections and hydrocephalus. We observed perfect concordance of the NME5 genotypes with the PCD phenotype in all three affected Alaskan Malamutes and more than 1000 controls. The fact that the third case, which had no documented close relationship to the initial two cases, was homozygous for the same rare mutant NME5 allele, strongly supports our hypothesis that NME5:c.43delA causes the PCD phenotype. We confirmed absence of NME5 protein expression in nasal epithelium of an affected dog. Our results enable genetic testing in dogs and identify NME5 as novel candidate gene for unsolved human PCD cases.Peer reviewe

Carbon Nanotube Solar Cells

We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement