An Efficient Algorithm for Optimizing Adaptive Quantum Metrology Processes

Quantum-enhanced metrology infers an unknown quantity with accuracy beyond the standard quantum limit (SQL). Feedback-based metrological techniques are promising for beating the SQL but devising the feedback procedures is difficult and inefficient. Here we introduce an efficient self-learning swarm-intelligence algorithm for devising feedback-based quantum metrological procedures. Our algorithm can be trained with simulated or real-world trials and accommodates experimental imperfections, losses, and decoherence

Force Distributions in Frictional Granular Media

We report a joint experimental and theoretical investigation of the probability distribution functions (pdf's) of the normal and tangential (frictional) forces in amorphous frictional media. We consider both the joint pdf of normal and tangential forces together, and the marginal pdf's of normal forces separately and tangential forces separately. A maximum entropy formalism is utilized for all these cases after identifying the appropriate constraints. Excellent agreements with both experimental and simulational data are reported. The proposed joint pdf (which appears new to the literature) predicts giant slip events at low pressures, again in agreement with observations.Comment: 13 pages, 15 figure

The contribution of nitrate respiration to the energy budget of the symbiotic clam Lucinoma aequizonata: a calorimetric study

Heat production and nitrate respiration rates were measured simultaneously in the gill tissue of Lucinoma aequizonata. This marine bivalve contains chemoautotrophic, intracellular, bacterial symbionts in its gill tissue. The symbionts show constitutive anaerobic respiration, using nitrate instead of oxygen as a terminal electron acceptor. An immediate increase in heat production was observed after the addition of nitrate to the perfusion medium of the calorimeter and this was accompanied by the appearance of nitrite in the effluent sea water. The nitrate-stimulated heat output was similar under aerobic and anaerobic conditions, which is consistent with the constitutive nature of nitrate respiration. The amount of heat released was dependent on the concentration of nitrate in the perfusion medium. At nitrate concentrations between 0.5 and 5 mmol l-1, the total heat production was increased over twofold relative to unstimulated baseline values. A mean (±s.e.m.) experimental enthalpy of -130±22.6 kJ mol-1 nitrite (N=13) was measured for this concentration range

Growth rates of interface-feeding spionid polychaetes in simulated tidal currents

Most spionid polychaetes switch from surface deposit feeding to suspension feeding as current speed and the flux of suspended food increase. Previous experiments testing the effects of flow on the growth of facultative, interface feeders have been limited to very simplified flow regimes such as constant, unidirectional currents. To measure the growth of interface-feeding spionids in more realistic currents, we programmed two identical counter-rotating annular flumes to simulate two different semidiurnal tidal currents. Each regime included four speeds that varied in hourly steps. At 5 mm above bottom, speeds in the slower flow regime were 0, 2.5, 5, and 7.5 cm s−1. Speeds in the faster regime were 0, 4, 8, and 12 cm s−11. Every 6 h, after each hour at 0 cm s−11, the flume rotation was reversed to simulate the directional shift between ebb and flood currents. The 12-h periods were repeated over 96 h. The experiment included eight 4-d runs of paired slow- and fast-flow flumes. Field-collected sediment and a nonliving algal slurry were added to control deposited and suspended food. Individuals of four species were measured for body volumes before and after each 4-d run: Polydora cornuta, Streblospio benedicti, Pygospio elegans, and Spio setosa. Each species except S. setosa was divided a priori into two size classes. Both small and large P. cornuta grew significantly faster in the fast-flow regime. Large P. elegans grew significantly faster in the fast-flow regime, but the growth rates of small P. elegans did not differ between regimes. Neither size class of S. benedicti grew at significantly different rates between flow regimes, and the broad size class of S. setosa did not show significant flow-dependent growth. The significant growth responses of two of the four species to moderate differences in tidal flow over a short time period underscore the impact flow can have on the population dynamics of some interface-feeding spionids. The differences among species suggest that variability in tidal currents can influence the structure and dynamics of communities in which spionids are often important and abundant

Nitrate respiration in chemoautotrophic symbionts of the bivalve Lucinoma aequizonata

Chemoautotrophic bacteria live symbiotically in gills of Lucinoma aequizonata, an infaunal clam inhabiting an oxygen-poor environment. These intracellular symbionts respire nitrate, i.e. they use nitrate instead of oxygen as a terminal electron acceptor in the respiratory chain. Nitrate is only reduced to nitrite and not further to nitrogen gas. Nitrate is respired by the symbionts under fully aerobic conditions at the same rate as under anaerobic conditions. The bacterial symbionts contain a nitrate reductase that is associated with the membrane-containing fraction of the symbiont cell and that is sensitive to respiratory inhibitors; both features are consistent with the respiratory role of this enzyme. A review of nitrate reductase in chemoautotrophic syrnbionts suggests that nitrate respiration may be common among these symbioses. Symbiont nitrate reductase may be an ecologically important factor permitting the survival of animal hosts in oxygen-poor environments

Streptomyces axinellae sp. nov., isolated from the Mediterranean sponge Axinella polypoides (Porifera)

An actinomycete strain, isolated from the marine sponge Axinella polypoides collected from Banyuls-sur-Mer, France, was characterized using a polyphasic approach. Based on its chemotaxonomic and morphological characteristics, strain Pol001(T) belongs to the genus Streptomyces. The strain is characterized by ll-diaminopimelic acid in the cell wall, menaquinones MK-9(H(4), H(6), H(8)) and a DNA G+C content of 71.0 mol%. It forms a separate phyletic line based on phylogenetic analyses of the nearly complete 16S rRNA gene sequence. Strain Pol001(T) could be differentiated from other closely related Streptomyces species with validly published names by phenotypic and genotypic analysis. DNA-DNA hybridization between strain Pol001(T) and closely related reference strains further confirmed that strain Pol001(T) represents a novel taxon of the genus Streptomyces. Therefore, it is proposed that strain Pol001(T) represents a novel species in the genus Streptomyces, Streptomyces axinellae sp. nov.; the type strain is Pol001(T) (=DSM 41948(T) =CIP 109838(T))

Sounds Like a Fit! Wording in Recruitment Advertisements and Recruiter Gender Affect Women’s Pursuit of Career Development Programs via Anticipated Belongingness

Following calls for research to increase gender equality, we investigated women's intentions to pursue career opportunities, in the form of career development programs. We built on lack of fit and signaling theory to argue that women's but not men's pursuit of career opportunities would be influenced by recruiter gender and gender‐stereotypical wording in recruitment advertisements. We conducted two studies in Germany. In Study 1 (video‐based experiment with 329 university students), we found that when a male recruiter used stereotypically masculine compared to feminine wording, female students anticipated lower belongingness, expected lower success of an application, and indicated lower application intentions for career opportunities. These differences in female students’ evaluations disappeared when the recruiter was female. While Study 2 (experimental vignette study with 545 employees) replicates the negative effects of masculine wording for female employees; the buffering effect of female recruiters was only replicated for younger, but not for older female employees. Women's anticipated belongingness mediated the relationship between advertisement wording and application intentions when the recruiter was male. Recruiter gender and wording had no effects on men. Our work contributes to a better understanding of when and why contextual characteristics in the recruitment process influence women's pursuit of career opportunities