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The boll weevil spread across the South from 1892 to 1922 with devastating effect on cotton cultivation. The resulting shift away from this child labor–intensive crop lowered the opportunity cost of school attendance. We investigate the insect’s long-run effect on educational attainment using a sample of adults from the 1940 census linked back to their childhood census records. Both white and black children who were young (ages 4 to 9) when the weevil arrived saw increased educational attainment by 0.24 to 0.36 years. Our results demonstrate the potential for conflict between child labor in agriculture and educational attainment.
Microwave plasma chemical vapor deposition (MPCVD) was used to diffuse boron into tantalum using plasma initiated from a feedgas mixture containing hydrogen and diborane. The role of substrate temperature and substrate bias in influencing surface chemical structure and hardness was investigated. X-ray diffraction shows that increased temperature results in increased TaB2 formation (relative to TaB) along with increased strain in the tantalum body-centered cubic lattice. Once the strained tantalum becomes locally supersaturated with boron, TaB and TaB2 precipitate. Additional boron remains in a solid solution within the tantalum. The combination of precipitation and solid solution hardening along with boron-induced lattice strain may help explain the 40 GPa average hardness measured by nanoindentation. Application of negative substrate bias did not further increase the hardness, possibly due to etching from increased ion bombardment. These results show that MPCVD is a viable method for synthesis of superhard borides based on plasma-assisted diffusion.
The past decade has seen a surge of reports and investigations into cases of autoimmune-mediated encephalitis. The increasing recognition of these disorders is especially of relevance to the fields of neurology and psychiatry. Autoimmune encephalitis involves antibodies against synaptic receptors, neuronal cell surface proteins and intracellular targets. These disorders feature prominent symptoms of cognitive impairment and behavioural changes, often associated with the presence of seizures. Early in the clinical course, autoimmune encephalitis may manifest as psychiatric symptoms of psychosis and involve psychiatry as an initial point of contact. Although commonly associated with malignancy, these disorders can present in the absence of an inciting neoplasm. The identification of autoimmune encephalitis is of clinical importance as a large proportion of individuals experience a response to immunotherapy. This review focuses on the current state of knowledge on n-methyl-d-aspartate (NMDA) receptor-associated encephalitis and limbic encephalitis, the latter predominantly involving antibodies against the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, the γ-aminobutyric acid (GABA)B receptor and leucine-rich glioma-inactivated 1 (LGI1) protein. In addition, we briefly describe anti-dopamine D2 receptor encephalitis. A summary of the literature will focus on common clinical presentations and course, diagnostic approaches and response to treatment. Since a substantial proportion of patients with autoimmune encephalitis exhibit symptoms of psychosis, the relevance of this disorder to theories of psychosis and schizophrenia will also be discussed.
The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
Chemically defended benthic macroalgae that dominate shallow, hard bottom communities along the western Antarctic Peninsula support very high densities of mesograzers, particularly amphipods but also small gastropods. Previous studies have demonstrated that the macroalgae and amphipods form a mutualistic relationship. The chemically defended macroalgae provide the amphipods with a refuge from predation while the macroalgae benefit from the amphipods greatly reducing surface fouling by smaller algae. One of the three most important macroalgae in terms of overstory cover, Himantothallus grandifolius, forms huge blades that can carpet the benthos. Field observations suggest that gastropods may be higher in relative abundance in proportion to amphipods on H. grandifolius than on other overstory macroalgae. The present study documents the finding that natural abundances of gastropods on H. grandifolius maintained in mesocosms reduce fouling by microscopic algae, primarily diatoms. However, amphipods are probably also important in keeping the macroalga clean of diatoms in nature. In a smaller scale experiment, three gastropod species were differentially effective at reducing diatom coverage on H. grandifolius. The hypothesis that gastropods benefit from associating with H. grandifolius in potentially gaining a refuge from sea-star predation was also tested but not supported by the experimental results.
Small perturbations to a steady uniform granular chute flow can grow as the material moves downslope and develop into a series of surface waves that travel faster than the bulk flow. This roll wave instability has important implications for the mitigation of hazards due to geophysical mass flows, such as snow avalanches, debris flows and landslides, because the resulting waves tend to merge and become much deeper and more destructive than the uniform flow from which they form. Natural flows are usually highly polydisperse and their dynamics is significantly complicated by the particle size segregation that occurs within them. This study investigates the kinematics of such flows theoretically and through small-scale experiments that use a mixture of large and small glass spheres. It is shown that large particles, which segregate to the surface of the flow, are always concentrated near the crests of roll waves. There are different mechanisms for this depending on the relative speed of the waves, compared to the speed of particles at the free surface, as well as on the particle concentration. If all particles at the surface travel more slowly than the waves, the large particles become concentrated as the shock-like wavefronts pass them. This is due to a concertina-like effect in the frame of the moving wave, in which large particles move slowly backwards through the crest, but travel quickly in the troughs between the crests. If, instead, some particles on the surface travel more quickly than the wave and some move slower, then, at low concentrations, large particles can move towards the wave crest from both the forward and rearward sides. This results in isolated regions of large particles that are trapped at the crest of each wave, separated by regions where the flow is thinner and free of large particles. There is also a third regime arising when all surface particles travel faster than the waves, which has large particles present everywhere but with a sharp increase in their concentration towards the wave fronts. In all cases, the significantly enhanced large particle concentration at wave crests means that such flows in nature can be especially destructive and thus particularly hazardous.
In this paper we show that the natural action of the symmetric group acting on the product space
endowed with a Bernoulli measure is approximately transitive. We also extend the result to a larger class of probability measures.
Azaperone can reduce stress caused by weaning and relocation of breeding sows, but its effects on reproductive processes are still poorly understood. The primary aim of this study was to describe and compare the endocrine and ovarian activity in ultrasonographically monitored second parity sows, with or without azaperone treatment at weaning (2 mg/kg BW i.m.). The intervals from weaning to the onset of estrus and ovulation were both greater (P<0.05) in azaperone-treated (n=12) than in control sows (n=12) by ~12 h. Mean daily growth rates of identified antral follicles were less (P<0.05) in azaperone-treated than in control sows (1.08±0.17 v.1.23±0.18 mm/day; mean±SD) and treated animals exceeded (P<0.05) controls in the mean ovulation rate (13.7±1.3 v. 12.6±1.2). A transient suppression of cortisol release was observed in the treatment group (at 10 and 30 min after azaperone injections) but circulating cortisol concentrations were variable in both groups of sows for the remainder of the study. The preovulatory rise in LH and estradiol secretion was delayed (P<0.05), and the duration of the LH surge was greater (P<0.001) in azaperone-treated sows compared with their control counterparts. The amplitude of episodic fluctuations in serum cortisol concentrations was correlated with the number of stillborn piglets in control sows (r=0.63, P=0.04). The amplitude and concentration of the preovulatory rise in estradiol secretion were negatively correlated with ovulatory response and litter size (r=−0.63 to −0.82, P<0.05), whereas the time at which the LH surge ended was directly related to the number of live-born piglets (r=0.82, P=0.002) in azaperone-treated animals. The present results indicate that administration of azaperone at weaning had a profound effect on preovulatory LH secretion as well as growth kinetics and estrogenicity of ovarian antral follicles. However, the causative associations among various characteristics of the preovulatory LH discharge, ovarian and adrenal steroid secretion post-weaning, and reproductive variables in sows remain equivocal.
Introduction: The majority of attempts to stop smoking end in failure. One way to improve success may be to explore different combinations of existing cessation medications.
Aims: This observational study examined ‘triple therapy’ (varenicline + nicotine patch + nicotine lozenge) in 36 smokers trying to quit.
Methods: A 12-week, observational study exploring tolerability, via adverse events (AEs) elicited at each of nine phone assessments. Secondary outcomes included satisfaction rates, medication changes and self-reported quit rates at week 12.
Results: Thirty five of thirty six participants reported at least one AE. Insomnia (75%), abnormal dreams (72%) and nausea (64%) were most common. Most were mild to moderate. No deaths, hospitalisations, cardiovascular events or suicidality were reported. Six participants (17%) decreased the dose of at least one medication, 5 (14%) decreased the dose then discontinued at least one medication and 13 (36%) discontinued at least one medication without trying a lesser dose. Participants were highly satisfied with their medications, and 58% reported quitting at 12 weeks, with 38% reporting prolonged abstinence.
Conclusions: Despite high rates of AEs and medication changes, high rates of satisfaction and self-reported quitting, with no serious AEs, were observed with triple therapy. Additional data on tolerability and efficacy are needed.
Predicting recurrent Clostridium difficile infection (rCDI) remains difficult. METHODS. We employed a retrospective cohort design. Granular electronic medical record (EMR) data had been collected from patients hospitalized at 21 Kaiser Permanente Northern California hospitals. The derivation dataset (2007–2013) included data from 9,386 patients who experienced incident CDI (iCDI) and 1,311 who experienced their first CDI recurrences (rCDI). The validation dataset (2014) included data from 1,865 patients who experienced incident CDI and 144 who experienced rCDI. Using multiple techniques, including machine learning, we evaluated more than 150 potential predictors. Our final analyses evaluated 3 models with varying degrees of complexity and 1 previously published model.
Despite having a large multicenter cohort and access to granular EMR data (eg, vital signs, and laboratory test results), none of the models discriminated well (c statistics, 0.591–0.605), had good calibration, or had good explanatory power.
Our ability to predict rCDI remains limited. Given currently available EMR technology, improvements in prediction will require incorporating new variables because currently available data elements lack adequate explanatory power.
The years 1289–1313 witnessed particularly prolific minting activities at different southern and central Greek mints on behalf of different polities. The coin issues are of great economic and political relevance, and therefore of interest to modern historians. Our understanding of these is based on traditional sources, either numismatic (types and finds), or historical. This paper aims to investigate the possibilities of adding further details to the picture through archaeometry. Specifically, tournois pennies of the three main mints of the region (Clarentza, Thebes, Naupaktos) excavated at Ancient Corinth were analysed according to two different non-destructive methods, X-ray fluorescence spectrometry (XRF) and laser-induced breakdown spectroscopy (LIBS). The resulting relative silver percentages and the fingerprints of the trace elements have supported our attempts to put the different coin types in chronological order and to add detail to the context and intent for each one of these. A vivid picture of monetary production emerges. The different issuing authorities were usually intent on maintaining a decent standard while variously trying to put pressure on rivals or to harmonise their productions with their allies. All the analysed mints were commercial in character, though they were subject to the great political changes affecting Greece in this period, the ambitions of the Angevin dynasty, the various challenges which it faced in Athens, the Peloponnese and the western Mainland, and finally the destructive arrival of the Catalans. In times of need, specifically military, these same mints could therefore rely on further bullion which reached them through internal or external political channels.
In this project we have involved four high-achieving pre-university summer placement students in the development of undergraduate teaching materials, namely tutorial videos for first year undergraduate Electrical and Electronic Engineering lab, and computer simulations of didactic semiconductor structures for an Electrical Science first year compulsory taught module. Here we describe our approach and preliminary results.