Proto-Sotho and the Sotho-Group

From the early years of the Nineteenth Century, language investigation had been undertaken to show what the relationship was between the languages of Africa, and in particular, Southern Africa. Perhaps one of the earliest informed investigators who postulated the concept of distinctive language "types" among the languages of Southern Africa and particularly with the Southern Bantu languages, was Heinrich » Lichtenstein. Writing in 1 808, he divided the peoples and languages of Southern Africa into two distinctive groups: the "Hottentots" and the Hottentot class, of languages, and the "Kaffirs", and the "Kaffir" class of languages. He clarified this relationship by stating, "All linguistic types of the South African aborigines must be classified as dialects of 2 either one or the other of these two principal classes." Implied in this statement is the concept that within the group composed of all the languages of his "Kaffir" class, as indeed of his "Hottentot" class, distinctive dialectical qualities came about through dialectical divergence. Despite this implication he did not attempt to analyse the relational aspects of each of the dialects composing his "principal ("Kaffir") class". 1 .0.01 It was not until twenty-seven years later, in 1837» that William Boyce, in his introduction to Archbell’s "Grammar of the Bechuana Language", enlarged upon Lichtenstein's division by stating, "....(that) the second division or family, of his South African languages....(is composed of) the sister dialects spoken by the Kafir and Bechuana tribes." The linguistic boundaries were now enlarged to include two distinctive linguistic families, rather than "types", viz. the Hottentot family and the Nguni ("Kafir") and Sotho (Bechuana) families. In 18 5O, J. W.Appleyard, produced his "The Kafir Language; comprising a sketch of its History; remarks upon its Nature and a Grammar". In this work he postulates four groups within our future Bantu family, those of Congo, Damara (i.e. Herero), Sechuana and "Kafir" It is noteworthy that in this work he classified Sotho under the "Sechuana"^ group, from which it could be implied that Sotho was either a dialect or a separate Cluster of the Tswana group. This is the first discernible effort to note that under the main families of the Southern Africa geographical areas there could be dialects that were affiliated to larger groups

Shrinkage estimators for multiple parameters

The estimation of a parameter vector for multivariate distributions has been studied extensively in the classical, Bayesian, empirical Bayes, and James-Stein framework. Shrinkage estimation procedures of Thompson and Albert are extended to form new estimators of such parameter vectors. These estimators are given for the normal, Poisson and gamma setting and the consequences of varying the focus and flexibility of the shrinkers are studied. When possible, the resulting estimators are given an empirical Bayes interpretation;These estimators are also utilized in estimating the mean of a stratified normal population;Using the method of moments technique, an empirical Bayes estimator of a multivariate scale parameter vector is developed and studied;Also, multivariate estimators are proposed that improve upon the simultaneous estimation procedures of Brown and Shinozaki. The major tool is the use of integration by parts techniques in solving basic differential inequalities;When possible, the estimators are evaluated through simulation studies

Crowdsourcing Job Satisfaction Data: Examining the Construct Validity of Glassdoor.com Ratings

Researchers, practitioners, and job seekers now routinely use crowdsourced data about organizations for both decision-making and research purposes. Despite the popularity of such websites, empirical evidence regarding their validity is generally absent. In this study, we tackled this problem by combining two curated datasets: (a) the results of the 2017 Federal Employee Viewpoint Survey (FEVS), which contains facet-level job satisfaction ratings from 407,789 US federal employees, and which we aggregated to the agency level, and (b) current overall and facet ratings of job satisfaction of the federal agencies contained within FEVS from Glassdoor.com as scraped from the Glassdoor application programming interface (API) within a month of the FEVS survey’s administration. Using these data, we examined convergent validity, discriminant validity, and methods effects for the measurement of both overall and facet-level job satisfaction by analyzing a multitrait-multimethod matrix (MTMM). Most centrally, we provide evidence that overall Glassdoor ratings of satisfaction within US federal agencies correlate moderately with aggregated FEVS overall ratings (r = .516), supporting the validity of the overall Glassdoor rating as a measure of overall job satisfaction aggregated to the organizational level. In contrast, the validity of facet-level measurement was not well-supported. Overall, given varying strengths and weaknesses with both Glassdoor and survey data, we recommend the combined use of both traditional and crowdsourced data on organizational characteristics for both research and practice

Quantitative modeling of the emergence of macroscopic grid-like representations

When subjects navigate through spatial environments, grid cells exhibit firing fields that are arranged in a triangular grid pattern. Direct recordings of grid cells from the human brain are rare. Hence, functional magnetic resonance imaging (fMRI) studies proposed an indirect measure of entorhinal grid-cell activity, quantified as hexadirectional modulation of fMRI activity as a function of the subject’s movement direction. However, it remains unclear how the activity of a population of grid cells may exhibit hexadirectional modulation. Here, we use numerical simulations and analytical calculations to suggest that this hexadirectional modulation is best explained by head-direction tuning aligned to the grid axes, whereas it is not clearly supported by a bias of grid cells toward a particular phase offset. Firing-rate adaptation can result in hexadirectional modulation, but the available cellular data is insufficient to clearly support or refute this option. The magnitude of hexadirectional modulation furthermore depends considerably on the subject’s navigation pattern, indicating that future fMRI studies could be designed to test which hypothesis most likely accounts for the fMRI measure of grid cells. Our findings also underline the importance of quantifying the properties of human grid cells to further elucidate how hexadirectional modulations of fMRI activity may emerge

Pay for Performance, Satisfaction and Retention in Longitudinal Crowdsourced Research

In the social and cognitive sciences, crowdsourcing provides up to half of all research participants. Despite this popularity, researchers typically do not conceptualize participants accurately, as gig-economy worker-participants. Applying theories of employee motivation and the psychological contract between employees and employers, we hypothesized that pay and pay raises would drive worker-participant satisfaction, performance, and retention in a longitudinal study. In an experiment hiring 359 Amazon Mechanical Turk Workers, we found that initial pay, relative increase of pay over time, and overall pay did not have substantial influence on subsequent performance. However, pay significantly predicted participants\u27 perceived choice, justice perceptions, and attrition. Given this, we conclude that worker-participants are particularly vulnerable to exploitation, having relatively low power to negotiate pay. Results of this study suggest that researchers wishing to crowdsource research participants using MTurk might not face practical dangers such as decreased performance as a result of lower pay, but they must recognize an ethical obligation to treat Workers fairly

Magnetic resonance imaging plaque hemorrhage for risk stratification in carotid artery disease with moderate risk under current medical therapy

Background and Purpose—Magnetic resonance imaging (MRI)–defined carotid plaque hemorrhage (MRIPH) can predict recurrent cerebrovascular ischemic events in severe symptomatic carotid stenosis. It is less clear whether MRIPH can improve risk stratification despite optimized medical secondary prevention in those with moderate risk. Methods—One-hundred fifty-one symptomatic patients with 30% to 99% carotid artery stenosis (median age: 77, 60.5% men) clinically deemed to not benefit from endarterectomy were prospectively recruited to undergo MRI and clinical follow-up (mean, 22 months). The clinical carotid artery risk score could be evaluated in 88 patients. MRIPH+ve was defined as plaque intensity >150% that of adjacent muscle. Survival analyses were performed with recurrent infarction (stroke or diffusion-positive cerebral ischemia) as the main end point. Results—Fifty-five participants showed MRIPH+ve; 47 had low, 36 intermediate, and 5 high carotid artery risk scores. Cox regression showed MRIPH as a strong predictor of future infarction (hazard ratio, 5.2; 95% confidence interval, 1.64–16.34; P=0.005, corrected for degree of stenosis), also in the subgroup with 50% to 69% stenosis (hazard ratio, 4.1; 95% confidence interval, 1–16.8; P=0.049). The absolute risk of future infarction was 31.7% at 3 years in MRIPH+ve versus 1.8% in patients without (P<0.002). MRIPH increased cumulative risk difference of future infarction by 47.1% at 3 years in those with intermediate carotid artery risk score (P=0.004). Conclusions—The study confirms MRIPH to be a powerful risk marker in symptomatic carotid stenosis with added value over current risk scores. For patients undergoing current secondary prevention medication with clinically uncertain benefit from recanalization, that is, those with moderate degree stenosis and intermediate carotid artery risk scores, MRIPH offers additional risk stratification

Looking for pulsations in HgMn stars through CoRoT lightcurves

HgMn Chemically Peculiar stars are among the quietest stars of the main-sequence. However, according to theoretical predictions, these stars could have pulsations related to the very strong overabundances of iron peak elements, which are produced by atomic diffusion in upper layers. Such pulsations have never been detected from ground based observations. Our aim is to search for signatures of pulsations in HgMn stars using the high quality lightcurves provided by the CoRoT satellite. We identified three faint stars (V>12), from VLT-GIRAFFE multiobject spectrograph survey in a field which was planned for observation by CoRoT. They present the typical characteristics of HgMn stars. They were observed by the CoRoT satellite during the long run (131 days) which started from the 24th of October 2007, with the exoplanets CCD's (Additional Programme). In the present work, we present the analysis of the ground based spectra of these three stars and the analysis of the corresponding CoRoT lightcurves. Two of these three HgMn candidates show low amplitude (less than 1.6 mmag) periodic variations (4.3 and 2.53 days respectively, with harmonics) which are compatible with periods predicted by theoretical models.Comment: Accepted paper in A&A (7 May 2009

The Cambridge Centre for Ageing and Neuroscience (Cam-CAN) data repository : structural and functional MRI, MEG, and cognitive data from a cross-sectional adult lifespan sample

Peer reviewe

Individuals with higher metabolic rates have lower levels of reactive oxygen species in vivo

There is increasing interest in the effect of energy metabolism on oxidative stress, but much ambiguity over the relationship between the rate of oxygen consumption and the generation of reactive oxygen species (ROS). Production of ROS (such as hydrogen peroxide, H2O2) in the mitochondria is primarily inferred indirectly from measurements in vitro, which may not reflect actual ROS production in living animals. Here, we measured in vivo H2O2 content using the recently developed MitoB probe that becomes concentrated in the mitochondria of living organisms, where it is converted by H2O2 into an alternative form termed MitoP; the ratio of MitoP/MitoB indicates the level of mitochondrial H2O2 in vivo. Using the brown trout Salmo trutta, we tested whether this measurement of in vivo H2O2 content over a 24 h-period was related to interindividual variation in standard metabolic rate (SMR). We showed that the H2O2 content varied up to 26-fold among fish of the same age and under identical environmental conditions and nutritional states. Interindividual variation in H2O2 content was unrelated to mitochondrial density but was significantly associated with SMR: fish with a higher mass-independent SMR had a lower level of H2O2. The mechanism underlying this observed relationship between SMR and in vivo H2O2 content requires further investigation, but may implicate mitochondrial uncoupling which can simultaneously increase SMR but reduce ROS production. To our knowledge, this is the first study in living organisms to show that individuals with higher oxygen consumption rates can actually have lower levels of H2O2