CNT effective interfacial energy and pre-exponential kinetic factor from measured NaCl crystal nucleation time distributions in contracting microdroplets

Nucleation, the birth of a stable cluster from disorder, is inherently stochastic. Yet up to date, there are no quantitative studies on NaCl nucleation that accounts for its stochastic nature. Here, we report the first stochastic treatment of NaCl-water nucleation kinetics. Using a recently developed microfluidic system and evaporation model, our measured interfacial energies extracted from a modified Poisson distribution of nucleation time show an excellent agreement with theoretical predictions. Furthermore, analysis of nucleation parameters in 0.5 pL, 1.5pL and 5.5 pL microdroplets reveals an interesting interplay between kinetic confinement and shifting of nucleation mechanisms. Overall, our findings highlight the need to treat nucleation stochastically rather deterministically to bridge the gap between theory and experiment

Particle size distributions and performance of preferential crystallization of L-asparagine·H2O with tailor-made additives

Preferential crystallization (PC) is a process to separate enantiomers. The efficiency of seeded, isothermal PC was enhanced using tailor-made additives to inhibit the crystallization of the counter-enantiomer. The inhibition of D-asparagine (D-Asn) monohydrate using D-glutamic acid (D-Glu) and D-aspartic acid (D-Asp) as additives in PC was investigated by comparing the purity, yield, and particle size distribution after PC of L-Asn·H2O from DL-Asn·H2O. The amount of pure L-Asn·H2O solid product that can be produced before crystallization of the counter-enantiomer is higher when using the additives D-Asp and D-Glu. However, the crystal size of L-Asn·H2O increases faster in PC without additives than in PC with additives. This means that the additives inhibit not only the crystallization of D-Asn·H2O but also the crystal growth of L-Asn·H2O

Effect of additives on the preferential crystallization of L-asparagine monohydrate

Preferential Crystallization (PC) is a popular process to separate enantiomers, however the nucleation and growth of the counter enantiomer during the process can compromise the enantiopurity of the final crystalline product. This research investigates the use of additives to inhibit the nucleation and growth of the counter enantiomer. In this study, we use L-asparagine monohydrate (L-Asn·H2O) as the preferred enantiomer in crystallization from DL-Asn·H2O solutions. Additives include both pure enantiomers of several related amino acid species. This allows investigation of differences in inhibition caused by additives that are of the same chirality and different chirality as the preferred enantiomer. The additives had no discernible effect on the solubility but had a small effect on the metastable limit, with additives tending to slightly widen the metastable zone but also make the zone widths more disperse. D-additives have a small effect on the growth rate of L-Asn·H2O but L-Asp and L-Glu strongly inhibit the growth rate of L-Asn·H2O in DL-Asn·H2O solution; there must also be a corresponding effect for D-Asp and D-Glu on D-Asn·H2O. Indeed, PC experiments showed that in order to obtain L-Asn·H2O from a PC while preventing the formation of D-Asn·H2O, D-Asp and D-Glu are suitable additives, leading to high yield and purity of pure L-Asn·H2O

Adherence to dietary guideline and 15-year risk of all-cause mortality

Past investigation of diet in relation to disease or mortality has tended to focus on individual nutrients. However, there has been a recent shift to now focus on overall patterns of food intake. The present study aims to investigate the relationship between diet quality reflecting adherence to dietary guidelines and mortality in a sample of older Australians, and to report on the relationship between core food groups and diet quality. This was a population-based cohort study of persons aged 49 years or older at baseline, living in two postcode areas west of Sydney, Australia. Baseline dietary data were collected during 1992–4, from 2897 people using a 145-item Willett-derived FFQ. A modified version of the Healthy Eating Index for Australians was developed to determine diet quality scores. The Australian National Death Index provided 15-year mortality data using multiple data linkage steps. Hazard risk (HR) ratios and 95 % CI for mortality were assessed for diet quality. Subjects in quintile 5 (highest) of the Total Diet Score had a 21 % reduced risk of all-cause mortality (HR 0·79, 95 % CI 0·63, 0·98, Ptrend = 0·04) compared with those in quintile 1 (lowest) after multivariate adjustment. The present study provides longitudinal support for a reduced risk of all-cause mortality in an older population who have greater compliance with published dietary guidelines

Forward to the past: reinventing intelligence-led policing in Britain

Drawing on archival, secondary material and primary research, this paper examines 'Total Policing', the strategy recently adopted by London's Metropolitan Police. It situates that analysis within a critical examination of other innovative policing strategies previously employed in Britain. It argues that the prospects for Total Policing depend upon the resolution of long-standing problems such as: the inadequacy and inefficiency of local intelligence work; the paucity of evidence for the success of commanders' previous efforts to harness together the component parts of their forces in pursuit of a single mission; and, above all, a seeming inability to learn the lessons of the past. © 2013 © 2013 Taylor & Francis

Validity of self-reported weight, height, and body mass index among university students in Thailand: Implications for population studies of obesity in developing countries

<p>Abstract</p> <p>Background</p> <p>Large-scale epidemiological studies commonly use self-reported weights and heights to determine weight status. Validity of such self-reported data has been assessed primarily in Western populations in developed countries, although its use is widespread in developing countries. We examine the validity of obesity based on self-reported data in an Asian developing country, and derive improved obesity prevalence estimates using the "reduced BMI threshold" method.</p> <p>Methods</p> <p>Self-reported and measured heights and weights were obtained from 741 students attending an open university in Thailand (mean age 34 years). Receiver operator characteristic techniques were applied to derive "reduced BMI thresholds."</p> <p>Results</p> <p>Height was over-reported by a mean of 1.54 cm (SD 2.23) in men and 1.33 cm (1.84) in women. Weight was under-reported by 0.93 kg (3.47) in men and 0.62 kg (2.14) in women. Sensitivity and specificity for determining obesity (Thai BMI threshold 25 kg/m²) using self-reported data were 74.2% and 97.3%, respectively, for men and 71.9% and 100% for women. For men, reducing the BMI threshold to 24.5 kg/m²increased the estimated obesity prevalence based on self-reports from 29.1% to 33.8% (true prevalence was 36.9%). For women, using a BMI threshold of 24.4 kg/m², the improvement was from 12.0% to 15.9% (true prevalence 16.7%).</p> <p>Conclusion</p> <p>Young educated Thais under-report weight and over-report height in ways similar to their counterparts in developed countries. Simple adjustments to BMI thresholds will overcome these reporting biases for estimation of obesity prevalence. Our study suggests that self-reported weights and heights can provide economical and valid measures of weight status in high school-educated populations in developing countries.</p

How does risk flow in the credit default swap market?

We develop a framework to analyse the credit default swap (CDS) market as a network of risk transfers among counterparties. From a theoretical perspective, we introduce the notion of flow-of-risk and provide sufficient conditions for a bow-tie network architecture to endogenously emerge as a result of intermediation. This architecture shows three distinct sets of counterparties: (i) Ultimate Risk Sellers (URS), (ii) Dealers (indirectly connected to each other), (iii) Ultimate Risk Buyers (URB). We show that the probability of widespread distress due to counterparty risk is higher in a bow-tie architecture than in more fragmented network structures. Empirically, we analyse a unique global dataset of bilateral CDS exposures on major sovereign and financial reference entities in 2011–2014. We find the presence of a bow-tie network architecture consistently across both reference entities and time, and that the flow-of-risk originates from a large number of URSs (e.g. hedge funds) and ends up in a few leading URBs, most of which are non-banks (in particular asset managers). Finally, the analysis of the CDS portfolio composition of the URBs shows a high level of concentration: in particular, the top URBs often show large exposures to potentially correlated reference entities