Optomechanical Cavity Cooling of an Atomic Ensemble

We demonstrate cavity sideband cooling of a single collective motional mode of an atomic ensemble down to a mean phonon occupation number of 2.0(-0.3/+0.9). Both this minimum occupation number and the observed cooling rate are in good agreement with an optomechanical model. The cooling rate constant is proportional to the total photon scattering rate by the ensemble, demonstrating the cooperative character of the light-emission-induced cooling process. We deduce fundamental limits to cavity-cooling either the collective mode or, sympathetically, the single-atom degrees of freedom.Comment: Paper with supplemental material: 4+6 pages, 4 figures. Minor revisions of text. Supplemental material shortened by removal of supplementary figur

Bacterial translocation in the newborn rabbit: effect of age on frequency of translocation

Sepsis is a significant cause of morbidity and mortality in neonates, and in a significant number of cases no predisposing factors can be identified. We hypothesize that bacterial translocation (BT) may be the etiology of neonatal sepsis when no source is identified. Mesenteric lymph nodes (MLN), spleen (SPL), and liver (LIV) were harvested from 36 rabbit pups ranging in age from 4 to 24 days and divided into three groups based on their age: group I, 4–6 days; group II, 13–15 days; and group III, 22–24 days. Tissues from each organ were homogenized and placed in both aerobic and anaerobic environments. After 48 h the number of colony-forming units/g tissue was identified. The total percentage of positive growth was significantly higher in group I for MLN (33%) and LIV (23%) when compared to groups II and III (<4% for both groups). Gram-negative growth (as selected by MacConkey [MC] media) was significantly higher in all tissue specimens from group I (MLN + 35%, SPL = 20%, LIV = 25%) compared to groups II and III (0% growth in all MC plates, P <0.01). These data support the hypothesis that spontaneous BT occurs with significant frequency in the neonate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47149/1/383_2004_Article_BF00171174.pd

Anxiety-like behavior of prenatally stressed rats is associated with a selective reduction of glutamate release in the ventral hippocampus

Abnormalities of synaptic transmission and plasticity in the hippocampus represent an integral part of the altered programming triggered by early life stress. Prenatally restraint stressed (PRS) rats develop long-lasting biochemical and behavioral changes, which are the expression of an anxious/depressive-like phenotype. We report here that PRS rats showed a selective impairment of depolarization- or kainate-stimulated glutamate and 3HD-aspartate release in the ventral hippo campus, a region encoding memories related to stress and emotions. GABA release was un affected in PRS rats. As a consequence of reduced glutamate release, PRS rats were also highly resistant to kainate-induced seizures. Abnormalities of glutamate release were associated with large reductions in the levels of synaptic vesicle-related proteins, such as VAMP (synaptobrevin), syntaxin-1, synaptophysin, synapsin Ia/b and IIa, munc-18, and Rab3A in the ventral hippocampus of PRS rats. Anxiety-like behavior in male PRS (and control) rats was inversely related to the extent of depolarization-evoked glutamate release in the ventral hippocampus. A causal relationship between anxiety-like behavior and reduction in glutamate release was demonstrated usingamixtureofthemGlu2/3 receptor antagonist, LY341495, and the GABAB receptor antagonist, CGP52432, which was shown to amplify depolarization-evoked 3HD-aspartate release in the ventral hippocampus. Bilateral micro infusion of CGP52432 plus LY341495 in the ventral hippocampus abolished anxiety-like behavior in PRS rats. These findings indicate that an impairment of glutamate release in the ventral hippocampus is a key component of the neuro plastic program induced by PRS, and that strategies aimed at enhancing glutamate release in the ventral hippocampus correct the "anxious phenotype" caused by early life stress

Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring

Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip discharge spots traditionally monitored in caves and aims to support modelling approaches of karst hydrological processes

Determinants of methotrexate adherence in rheumatoid arthritis patients

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Where do the elderly die? The impact of nursing home utilisation on the place of death. Observations from a mortality cohort study in Flanders

BACKGROUND: Most of the research concerning place of death focuses on terminally ill patients (cancer patients) while the determinants of place of death of the elderly of the general population are not intensively studied. Studies showed the influence of gender, age, social-economical status and living arrangements on the place of death, but a facet not taken into account so far is the influence of the availability of nursing homes. METHODS: We conducted a survey of deaths, between January 1999 and December 2000 in a small densely populated area in Belgium, with a high availability of nursing homes (within 5 to 10 km of the place of residence of every elderly). We determined the incidence of total mortality (of subjects >60 years) from local official death registers that we consulted via the priest or the mortician of the local parish, to ask where the decedent had died and whether the deceased had lived in a nursing home. We compared the distribution of the places of death between parishes with a nursing home and with parishes without nursing home. RESULTS: 240 women and 217 men died during the two years study period. Only 22% died at home, while the majority (78%) died in an institutional setting, either a hospital (50%) or a nursing home (28%). Place of death was influenced by individual factors (age and gender) and the availability of a nursing home in the 'own' parish. The chance of in-hospital death was 65% higher for men (95% Confidence Interval [CI]: 14 to 138%; p = 0.008) and decreased by 4% (CI: -5.1% to -2.5%; p < 0.0001) for each year increase in age. Independent of gender and age, the chance of in-hospital death was 41% (CI: -60% to -13%; p = 0.008) lower in locations with a nursing home. CONCLUSION: Demographic, but especially social-contextual factors determine where elderly will end their life. The majority of elderly in Flanders die in an institution. Age, gender and living situation are predictors of the place of death but the embedment of a nursing home in the local community seems to be a key predictor

Retrieving hydrological connectivity from empirical causality in karst systems

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Updated tests of scaling and universality for the spin-spin correlations in the 2D and 3D spin-S Ising models using high-temperature expansions

We have extended, from order 12 through order 25, the high-temperature series expansions (in zero magnetic field) for the spin-spin correlations of the spin-S Ising models on the square, simple-cubic and body-centered-cubic lattices. On the basis of this large set of data, we confirm accurately the validity of the scaling and universality hypotheses by resuming several tests which involve the correlation function, its moments and the exponential or the second-moment correlation-lengths.Comment: 21 pages, 8 figure

Retrieving hydrological connectivity from empirical causality in karst systems

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