Direct, Non-Destructive Imaging of Magnetization in a Spin-1 Bose Gas

Polarization-dependent phase-contrast imaging is used to spatially resolve the magnetization of an optically trapped ultracold gas. This probe is applied to Larmor precession of degenerate and nondegenerate spin-1 $^{87}$Rb gases. Transverse magnetization of the Bose-Einstein condensate persists for the condensate lifetime, with a spatial response to magnetic field inhomogeneities consistent with a mean-field model of interactions. Rotational symmetry implies that the Larmor frequency of a spinor condensate be density-independent, and thus suitable for precise magnetometry with high spatial resolution. In comparison, the magnetization of the noncondensed gas decoheres rapidly.Comment: 4 pages, 4 figure

Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles

Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity

Using atomic interference to probe atom-surface interaction

We show that atomic interference in the reflection from two suitably polarized evanescent waves is sensitive to retardation effects in the atom-surface interaction for specific experimental parameters. We study the limit of short and long atomic de Broglie wavelength. The former case is analyzed in the semiclassical approximation (Landau-Zener model). The latter represents a quantum regime and is analyzed by solving numerically the associated coupled Schroedinger equations. We consider a specific experimental scheme and show the results for rubidium (short wavelength) and the much lighter meta-stable helium atom (long wavelength). The merits of each case are then discussed.Comment: 11 pages, including 6 figures, submitted to Phys. Rev. A, RevTeX sourc

Non-destructive, dynamic detectors for Bose-Einstein condensates

We propose and analyze a series of non-destructive, dynamic detectors for Bose-Einstein condensates based on photo-detectors operating at the shot noise limit. These detectors are compatible with real time feedback to the condensate. The signal to noise ratio of different detection schemes are compared subject to the constraint of minimal heating due to photon absorption and spontaneous emission. This constraint leads to different optimal operating points for interference-based schemes. We find the somewhat counter-intuitive result that without the presence of a cavity, interferometry causes as much destruction as absorption for optically thin clouds. For optically thick clouds, cavity-free interferometry is superior to absorption, but it still cannot be made arbitrarily non-destructive . We propose a cavity-based measurement of atomic density which can in principle be made arbitrarily non-destructive for a given signal to noise ratio

Dynamics of Dipolar Spinor Condensates

We study the semiclassical dynamics of a spinor condensate with the magnetic dipole-dipole interaction included. The time evolution of the population imbalance and the relative phase among different spin components depends greatly on the relative strength of interactions as well as on the initial conditions. The interplay of spin exchange and dipole-dipole interaction makes it possible to manipulate the atomic population on different components, leading to the phenomena of spontaneous magnetization and Macroscopic Quantum Self Trapping. Simple estimate demonstrates that these effects are accessible and controllable by modifying the geometry of the trapping potential.Comment: 13 pages,3 figure

Incorporation of DPP6a and DPP6K Variants in Ternary Kv4 Channel Complex Reconstitutes Properties of A-type K Current in Rat Cerebellar Granule Cells

Dipeptidyl peptidase-like protein 6 (DPP6) proteins co-assemble with Kv4 channel α-subunits and Kv channel-interacting proteins (KChIPs) to form channel protein complexes underlying neuronal somatodendritic A-type potassium current (ISA). DPP6 proteins are expressed as N-terminal variants (DPP6a, DPP6K, DPP6S, DPP6L) that result from alternative mRNA initiation and exhibit overlapping expression patterns. Here, we study the role DPP6 variants play in shaping the functional properties of ISA found in cerebellar granule (CG) cells using quantitative RT-PCR and voltage-clamp recordings of whole-cell currents from reconstituted channel complexes and native ISA channels. Differential expression of DPP6 variants was detected in rat CG cells, with DPP6K (41±3%)>DPP6a (33±3%)>>DPP6S (18±2%)>DPP6L (8±3%). To better understand how DPP6 variants shape native neuronal ISA, we focused on studying interactions between the two dominant variants, DPP6K and DPP6a. Although previous studies did not identify unique functional effects of DPP6K, we find that the unique N-terminus of DPP6K modulates the effects of KChIP proteins, slowing recovery and producing a negative shift in the steady-state inactivation curve. By contrast, DPP6a uses its distinct N-terminus to directly confer rapid N-type inactivation independently of KChIP3a. When DPP6a and DPP6K are co-expressed in ratios similar to those found in CG cells, their distinct effects compete in modulating channel function. The more rapid inactivation from DPP6a dominates during strong depolarization; however, DPP6K produces a negative shift in the steady-state inactivation curve and introduces a slow phase of recovery from inactivation. A direct comparison to the native CG cell ISA shows that these mixed effects are present in the native channels. Our results support the hypothesis that the precise expression and co-assembly of different auxiliary subunit variants are important factors in shaping the ISA functional properties in specific neuronal populations

Good prenatal detection rate of major birth defects in HIV-infected pregnant women in Italy

What's already known about this topic? Exposure to antiretroviral treatment in pregnancy does not seem to increase the risk of birth defects, but there is no information on the rate of prenatal detection of such defects. What does this study adds? We provide for the first time, in a national case series, information about prenatal detection rate in women with HIV (51.6% for any major defect, 66.7% for chromosomal abnormalities, and 85% for severe structural defect

Male Mating Rate Is Constrained by Seminal Fluid Availability in Bedbugs, Cimex lectularius

Sexual selection, differences in reproductive success between individuals, continues beyond acquiring a mating partner and affects ejaculate size and composition (sperm competition). Sperm and seminal fluid have very different roles in sperm competition but both components encompass production costs for the male. Theoretical models predict that males should spend ejaculate components prudently and differently for sperm and seminal fluid but empirical evidence for independent variation of sperm number and seminal fluid volume is scarce. It is also largely unknown how sperm and seminal fluid variation affect future mating rate. In bedbugs we developed a protocol to examine the role of seminal fluids in ejaculate allocation and its effect on future male mating rate. Using age-related changes in sperm and seminal fluid volume we estimated the lowest capacity at which mating activity started. We then showed that sexually active males allocate 12% of their sperm and 19% of their seminal fluid volume per mating and predicted that males would be depleted of seminal fluid but not of sperm. We tested (and confirmed) this prediction empirically. Finally, the slightly faster replenishment of seminal fluid compared to sperm did not outweigh the faster decrease during mating. Our results suggest that male mating rate can be constrained by the availability of seminal fluids. Our protocol might be applicable to a range of other organisms. We discuss the idea that economic considerations in sexual conflict research might benefit from distinguishing between costs and benefits that are ejaculate dose-dependent and those that are frequency-dependent on the mating rate per se

Atazanavir and darunavir in pregnant women with HIV: Evaluation of laboratory and clinical outcomes from an observational national study

Background: Atazanavir and darunavir represent the main HIV PIs recommended in pregnancy, but comparativedata in pregnant women are limited.We assessed the safety and activity profile of these two drugs in pregnancyusing data from a national observational study.Methods: Women with atazanavir or darunavir exposure in pregnancy were evaluated for laboratory measuresand main pregnancy outcomes (e.g. preterm delivery, low birthweight, non-elective caesarean section and neonatalgestational age-adjusted birthweight Z-score).Results: Final analysis included 500 pregnancies with either atazanavir (n"409) or darunavir (n"91) exposure.No differences in pregnancy outcomes, weight gain in pregnancy, drug discontinuations, undetectable HIV-RNA,haemoglobin, ALT, total cholesterol, HDL cholesterol and LDL cholesterol were observed between the twogroups. At third trimester, exposure to darunavir was associated with higher levels of plasma triglycerides(median 235.5 versus 179 mg/dL; P"0.032) and a higher total cholesterol/HDL cholesterol ratio (median 4.03versus 3.27; P"0.028) and exposure to atazanavir was associated with higher levels of plasma bilirubin (1.54versus 0.32 mg/dL; P<0.001).Conclusions: In this observational study, the two main HIV PIs currently recommended by perinatal guidelinesshowed similar safety and activity in pregnancy, with no evidence of differences between the two drugs in termsof main pregnancy outcomes. Based on the minor differences observed in laboratory measures, prescribingphysicians might prefer either drug in some particular situations where the different impacts of treatment onlipid profile and bilirubin may have clinical relevance