Solving mate shortages: Lowering standards, searching farther, and abstaining

Although much work on mating psychology has focused on mate preferences and responses to desirable sexual and romantic offers, less is known about what happens when individuals face a lack of mating options. We present 2 studies on (hypothetical) compensatory mating tactics. In Study 1 (N = 299), participants were asked to imagine they were struggling to find long-term and short-term mates and we revealed sex differences and context-specific effects consistent with parental investment theory. In Study 2 (N = 282), participants were asked to imagine they had been incapable of finding a short-term and long-term mate for 6 months despite actively trying to find one and then report the likelihood of abstaining, lowering their standards, and traveling farther to find a satisfactory partner; results largely (and conceptually) replicated those from Study 1 but document the role of attachment and (self-reported) mate value in accounting for individual differences in adopting the 3 mating tactics. We frame our results in terms of how people might solve mate shortages

Highly indistinguishable single photons from incoherently and coherently excited GaAs quantum dots

Semiconductor quantum dots are converging towards the demanding requirements of photonic quantum technologies. Among different systems, quantum dots with dimensions exceeding the free-exciton Bohr radius are appealing because of their high oscillator strengths. While this property has received much attention in the context of cavity quantum electrodynamics, little is known about the degree of indistinguishability of single photons consecutively emitted by such dots and on the proper excitation schemes to achieve high indistinguishability. A prominent example is represented by GaAs quantum dots obtained by local droplet etching, which recently outperformed other systems as triggered sources of entangled photon pairs. On these dots, we compare different single-photon excitation mechanisms, and we find (i) a "phonon bottleneck" and poor indistinguishability for conventional excitation via excited states and (ii) photon indistinguishablilities above 90% for both strictly resonant and for incoherent acoustic- and optical-phonon-assisted excitation. Among the excitation schemes, optical phonon-assisted excitation enables straightforward laser rejection without a compromise on the source brightness together with a high photon indistinguishability

Association between body weight, physical activity and food choices among metropolitan transit workers

<p>Abstract</p> <p>Background</p> <p>Associations between body weight, physical activity and dietary intake among a population of metropolitan transit workers are described.</p> <p>Methods</p> <p>Data were collected during October through December, 2005, as part of the baseline measures for a worksite weight gain prevention intervention in four metro transit bus garages. All garage employees were invited to complete behavioral surveys that assessed food choices and physical activity, and weight and height were directly measured. Seventy-eight percent (N = 1092) of all employees participated.</p> <p>Results</p> <p>The prevalence of obesity (BMI >= 30 kg/m²) was 56%. Over half of the transit workers reported consuming fruit (55%) and vegetables (59%) ≥ 3/week. Reported fast food restaurant frequency was low (13% visited ≥ 3/week). Drivers reported high levels of physical activity (eg. walking 93 minutes/day). However, an objective measure of physical activity measured only 16 minutes moderate/vigorous per day. Compared to other drivers, obese drivers reported significantly less vigorous physical activity, more time sitting, and more time watching television. Healthy eating, physical activity and weight management were perceived to be difficult at the worksite, particularly among obese transit workers, and perceived social support for these behaviors was modest. However, most workers perceived weight management and increased physical activity to be personally important for their health.</p> <p>Conclusion</p> <p>Although transit workers' self-report of fruit and vegetable intake, and physical activity was high, perceived access to physical activity and healthful eating opportunities at the worksite was low. Obese workers were significantly less physically active and were more likely to report work environmental barriers to physical activity.</p

Engineering of ecological niches to create stable artificial consortia for complex biotransformations

The design of controllable artificial microbial consortia has attracted considerable interest in recent years to capitalize on the inherent advantages in comparison to monocultures such as the distribution of the metabolic burden by division of labor, the modularity and the ability to convert complex substrates. One promising approach to control the consortia composition, function and stability is the provision of defined ecological niches fitted to the specific needs of the consortium members. In this review, we discuss recent examples for the creation of metabolic niches by biological engineering of resource partitioning and syntrophic interactions. Moreover, we introduce a complementing process engineering approach to provide defined spatial niches with differing abiotic conditions (e.g. O2, T, light) in stirred tank reactors harboring biofilms. This enables the co-cultivation of microorganisms with non-overlapping abiotic requirements and the control of the strain ratio in consortia characterized by substrate competition

Co-hydrolysis of hydrothermal and dilute acid pretreated populus slurries to support development of a high-throughput pretreatment system

Background The BioEnergy Science Center (BESC) developed a high-throughput screening method to rapidly identify low-recalcitrance biomass variants. Because the customary separation and analysis of liquid and solids between pretreatment and enzymatic hydrolysis used in conventional analyses is slow, labor-intensive and very difficult to automate, a streamlined approach we term 'co-hydrolysis' was developed. In this method, the solids and liquid in the pretreated biomass slurry are not separated, but instead hydrolysis is performed by adding enzymes to the whole pretreated slurry. The effects of pretreatment method, severity and solids loading on co-hydrolysis performance were investigated. Results For hydrothermal pretreatment at solids concentrations of 0.5 to 2%, high enzyme protein loadings of about 100 mg/g of substrate (glucan plus xylan) in the original poplar wood achieved glucose and xylose yields for co-hydrolysis that were comparable with those for washed solids. In addition, although poplar wood sugar yields from co-hydrolysis at 2% solids concentrations fell short of those from hydrolysis of washed solids after dilute sulfuric acid pretreatment even at high enzyme loadings, pretreatment at 0.5% solids concentrations resulted in similar yields for all but the lowest enzyme loading. Conclusions Overall, the influence of severity on susceptibility of pretreated substrates to enzymatic hydrolysis was clearly discernable, showing co-hydrolysis to be a viable approach for identifying plant-pretreatment-enzyme combinations with substantial advantages for sugar production

Work hours, weight status, and weight-related behaviors: a study of metro transit workers

<p>Abstract</p> <p>Background</p> <p>Associations between hours worked per week and Body Mass Index (BMI), food intake, physical activity, and perceptions of eating healthy at work were examined in a sample of transit workers.</p> <p>Methods</p> <p>Survey data were collected from 1086 transit workers. Participants reported hours worked per week, food choices, leisure-time physical activity and perceptions of the work environment with regard to healthy eating. Height and weight were measured for each participant. Multivariate linear and logistic regressions were conducted to examine associations between work hours and behavioral variables. Associations were examined in the full sample and stratified by gender.</p> <p>Results</p> <p>Transit workers working in the highest work hour categories had higher BMI and poorer dietary habits, with results differing by gender. Working 50 or more hours per week was associated with higher BMI among men but not women. Additionally, working 50 or more hours per week was significantly associated with higher frequency of accessing cold beverage, cold food, and snack vending machines among men. Working 40 or more hours per week was associated with higher frequency of accessing cold food vending machines among women. Reported frequency of fruit and vegetable intake was highest among women working 50 or more hours per week. Intake of sweets, sugar sweetened beverages, and fast food did not vary with work hours in men or women. Physical activity and perception of ease of eating healthy at work were not associated with work hours in men or women.</p> <p>Conclusions</p> <p>Long work hours were associated with more frequent use of garage vending machines and higher BMI in transit workers, with associations found primarily among men. Long work hours may increase dependence upon food availability at the worksite, which highlights the importance of availability of healthy food choices.</p

Force Based Measurement Method for Cooling Flow Quantification

AbstractQuantification of heat exchanger performance in its operative environment is in many engineering applications an essential task, and the air flow rate through the heat exchanger core is an important optimizing parameter. This paper explores an alternative method for quantifying the air flow rate through compact heat exchangers positioned in the underhood of a passenger car. Unlike conventional methods, typically relying on measurements of direct flow characteristics at discrete probe locations, the proposed method is based on the use of load-cells for direct measurement of the total force acting on the heat exchanger. The air flow rate is then calculated from the force measurement. A direct comparison with a conventional pressure based method is presented as both methods are applied on a passenger car’s radiator tested in a full scale wind tunnel using six different grill configurations. The measured air flow rates are presented and discussed over a wide range of test velocities. The advantages and draw backs of both approaches are compared and discussed in detail. The proposed method is non-intrusive, leaving the heat exchanger core intact, with no need for integration of measurement points over the core region. Due to the measuring principle, the load-cell method will inherently over-predict the air-flow rate. This error is quantified and an empirical correction function is investigated. This paper shows that the corrected force based method determines the air flow rate through a heat exchanger with an accuracy similar to that of traditional pressure/velocity methods while offering a considerable number of advantages

Robust excitation of C-band quantum dots for quantum communication

Building a quantum internet requires efficient and reliable quantum hardware, from photonic sources to quantum repeaters and detectors, ideally operating at telecommunication wavelengths. Thanks to their high brightness and single-photon purity, quantum dot (QD) sources hold the promise to achieve high communication rates for quantum-secured network applications. Furthermore, it was recently shown that excitation schemes, such as longitudinal acoustic phonon-assisted (LA) pumping, provide security benefits by scrambling the coherence between the emitted photon-number states. In this work, we investigate further advantages of LA-pumped quantum dots with emission in the telecom C-band as a core hardware component of the quantum internet. We experimentally demonstrate how varying the pump energy and spectral detuning with respect to the excitonic transition can improve quantum-secured communication rates and provide stable emission statistics regardless of network-environment fluctuations. These findings have significant implications for general implementations of QD single-photon sources in practical quantum communication networks

Modifiable risk-factors for keratinocyte cancers in Australia: a case-control study

Keratinocyte cancer is the most common malignancy in Caucasians. The aim of this study was to investigate risk-factors responsible for development of keratinocyte cancer in Australia. A case-control study was conducted, including 112 cases of squamous cell carcinoma (SCC), 95 cases of basal cell carcinoma (BCC) and 122 controls. Freckling during adolescence (SCC: odds ratio (OR) 1.04, p < 0.01; BCC: OR 1.05, p < 0.01), propensity to sunburn (SCC: OR 2.75, p = 0.01, BCC: OR 2.68 p = 0.01) and high cumulative sun-exposure (SCC: OR 2.43, p = 0.04; BCC: OR 2.36 p = 0.04) were independent risk-factors for both SCC and BCC. This study provides further evidence that a sun-sensitive phenotype and excessive sun-exposure during adulthood contribute to the risk of developing keratinocyte cancer. Wearing a hat, long-sleeved shirts, and sunscreen did not significantly reduce the risk of keratinocyte cancer in this study