The predictability of precipitation episodes during the West African dry season

Precipitation episodes in tropical West Africa (7-15°N, 10°W-10°E) during the dry season from November to March are rare, but can have significant impacts on human activities reaching from greening of pastures to spoiling harvests and health implications. Previous work has shown a link between these unseasonal rainfalls and extratropical disturbances via a decrease of surface pressure over the Sahara/Sahel and a subsequent inflow of moist air from the Gulf of Guinea. This paper supports the previously stated hypothesis that the extratropical influence leads to a high rainfall predictability through a careful analysis of operational 5 day forecasts from the European Centre for Medium-Range Weather Forecasts' (ECMWF) ensemble prediction system (EPS), which are evaluated using Global Precipitation Climatology Project (GPCP) and Tropical Rainfall Measuring Mission (TRMM) precipitation estimates for the 11 dry seasons 1998/99-2008/09. The long-term regional average of ensemble-mean precipitation lies between the two observational datasets, with GPCP being considerably wetter. Temporal correlations between the ensemble mean and observations are 0.8. Standard probabilistic evaluation methods such as reliability and relative operating characteristic (ROC) diagrams indicate remarkably good reliability, sharpness and skill across a range of precipitation thresholds. However, a categorical verification focusing on the most extreme ensemble mean values indicates too many false alarms. Despite the considerable observational uncertainty the results show that the ECMWF EPS is capable of predicting winter rainfall events in tropical West Africa with good accuracy, at least on regional spatial and synoptic time-scales, which should encourage West African weather services to capitalize more on the valuable information provided by ensemble prediction systems during the dry season

High Resolution, Differential, Near-infrared Transmission Spectroscopy of GJ 1214b

The nearby star GJ 1214 hosts a planet intermediate in radius and mass between Earth and Neptune, resulting in some uncertainty as to its nature. We have observed this planet, GJ 1214b, during transit with the high-resolution, near-infrared NIRSPEC spectrograph on the Keck II telescope, in order to characterize the planet's atmosphere. By cross-correlating the spectral changes through transit with a suite of theoretical atmosphere models, we search for variations associated with absorption in the planet atmosphere. Our observations are sufficient to rule out tested model atmospheres with wavelength-dependent transit depth variations >5e-4 over the wavelength range 2.1 - 2.4 micron. Our sensitivity is limited by variable slit loss and telluric transmission effects. We find no positive signatures but successfully rule out a number of plausible atmospheric models, including the default assumption of a gaseous, H-dominated atmosphere in chemical equilibrium. Such an atmosphere can be made consistent if the absorption due to methane is reduced. Clouds can also render such an atmosphere consistent with our observations, but only if they lie higher in the atmosphere than indicated by recent optical and infrared measurements. When taken in concert with constraints from other groups, our results support a consensus model in which the atmosphere of GJ 1214b contains significant H and He, but where methane is depleted. If this depletion is the result of photochemical processes, it may also produce a haze that suppresses spectral features in the optical.Comment: 32 pages, 15 figures, preprint, accepted to ApJ, responded to referee's comments. Comments welcom

A Comparison of Balance and Postural Stability Assessment Tools: BESS Versus NeuroCom Balance Manager

Postural stability assessment tools are one of the many ways concussions can be assessed and return to play decisions can be made; two of which are the Balance Error Scoring System (BESS) and force plate technology. OBJECTIVE: Validate the modified BESS used by Utah State University by comparing it to equivalent tests on the NeuroCom Balance Manager System. METHODS: 114 current or previous Utah State football players ranging in age from 18-24. Each athlete conducted a baseline BESS test during their pre-participation physical and NeuroCom testing was conducted during the summer of 2011. NeuroCom testing included a modified Clinical Test of Sensory Interaction on Balance (mCTSIB) both on a firm and foam surface, a single leg stance test with eyes open and closed on both a firm and foam surface, and a tandem walk test where end sway was recorded. BESS testing was done depending on when the athlete arrived at Utah State. Correlations were reported for athletes that arrived for the current year and also for the athletes that arrived for any year prior to that. A Welch\u27s T-Test was conducted to analyze any differences between the two groups. The tandem stance on the foam condition for the BESS had a statistically significant difference, so that variable was excluded and the adjusted correlations were then reported. There were eight correlation conditions that were determined by the individuals who could and could not complete the entire time on the single leg stance with eyes closed on a firm as well as a foam surface. RESULTS: The only variable associated with the NeuroCom Balance Manager that had consistent correlations with the composite BESS score was the CTSIB foam condition; with a 0.28 correlation with individuals regardless of single leg stance with eyes closed, 0.39 with individuals who completed the whole time on the firm without consideration for the foam, 0.27 with individuals who did not complete the whole time on the foam without consideration for the firm and 0.39 with individuals who could complete the whole time on the firm but not on the foam. CONCLUSION: There appears to be some correlation with CTSIB foam conditions and the composite BESS

Climatic and oceanic associations with daily rainfall extremes over southern Africa

Changes in climate variability and, in particular, changes in extreme climate events are likely to be of far more significance for environmentally vulnerable regions than changes in the mean state. It is generally accepted that sea-surface temperatures (SSTs) play an important role in modulating rainfall variability. Consequently, SSTs can be prescribed in global and regional climate modelling in order to study the physical mechanisms behind rainfall and its extremes. Using a satellite-based daily rainfall historical data set, this paper describes the main patterns of rainfall variability over southern Africa, identifies the dates when extreme rainfall occurs within these patterns, and shows the effect of resolution in trying to identify the location and intensity of SST anomalies associated with these extremes in the Atlantic and southwest Indian Ocean. Derived from a Principal Component Analysis (PCA), the results also suggest that, for the spatial pattern accounting for the highest amount of variability, extremes extracted at a higher spatial resolution do give a clearer indication regarding the location and intensity of anomalous SST regions. As the amount of variability explained by each spatial pattern defined by the PCA decreases, it would appear that extremes extracted at a lower resolution give a clearer indication of anomalous SST regions

Input variable selection in time-critical knowledge integration applications: A review, analysis, and recommendation paper

This is the post-print version of the final paper published in Advanced Engineering Informatics. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.The purpose of this research is twofold: first, to undertake a thorough appraisal of existing Input Variable Selection (IVS) methods within the context of time-critical and computation resource-limited dimensionality reduction problems; second, to demonstrate improvements to, and the application of, a recently proposed time-critical sensitivity analysis method called EventTracker to an environment science industrial use-case, i.e., sub-surface drilling. Producing time-critical accurate knowledge about the state of a system (effect) under computational and data acquisition (cause) constraints is a major challenge, especially if the knowledge required is critical to the system operation where the safety of operators or integrity of costly equipment is at stake. Understanding and interpreting, a chain of interrelated events, predicted or unpredicted, that may or may not result in a specific state of the system, is the core challenge of this research. The main objective is then to identify which set of input data signals has a significant impact on the set of system state information (i.e. output). Through a cause-effect analysis technique, the proposed technique supports the filtering of unsolicited data that can otherwise clog up the communication and computational capabilities of a standard supervisory control and data acquisition system. The paper analyzes the performance of input variable selection techniques from a series of perspectives. It then expands the categorization and assessment of sensitivity analysis methods in a structured framework that takes into account the relationship between inputs and outputs, the nature of their time series, and the computational effort required. The outcome of this analysis is that established methods have a limited suitability for use by time-critical variable selection applications. By way of a geological drilling monitoring scenario, the suitability of the proposed EventTracker Sensitivity Analysis method for use in high volume and time critical input variable selection problems is demonstrated.E

Shakespeare and the Cultural Capital Tension: Advancing Literacy in Rural Arkansas

A multi-faceted Shakespeare festival in a small town in rural east central Arkansas, part of a larger Community Literacy Advocacy Project, represents a concerted effort to alter the discourse of decline in this economically troubled region, but it also raises some challenging issues about how such projects distribute social and cultural capital among their participants

Perceptual grouping abilities in individuals with Autism Spectrum Disorder: exploring patterns of ability in relation to grouping type and levels of development

This study further investigates findings of impairment in Gestalt, but not global processing in Autism Spectrum Disorder (ASD) [Brosnan, Scott, Fox, & Pye, 2004]. Nineteen males with ASD and nineteen typically developing (TD) males matched by nonverbal ability, took part in five Gestalt perceptual grouping tasks. Results showed that performance differed according to grouping type. The ASD group showed typical performance for grouping by proximity and by alignment, impairment on low difficulty trials for orientation and luminance similarity, and general impairment for grouping by shape similarity. Group differences were also observed developmentally; for the ASD group, with the exception of grouping by shape similarity, perceptual grouping performance was poorer at lower than higher levels of nonverbal ability. In contrast, no developmental progression was observed in the TD controls

Soft topographic map for clustering and classification of bacteria

In this work a new method for clustering and building a topographic representation of a bacteria taxonomy is presented. The method is based on the analysis of stable parts of the genome, the so-called “housekeeping genes”. The proposed method generates topographic maps of the bacteria taxonomy, where relations among different type strains can be visually inspected and verified. Two well known DNA alignement algorithms are applied to the genomic sequences. Topographic maps are optimized to represent the similarity among the sequences according to their evolutionary distances. The experimental analysis is carried out on 147 type strains of the Gammaprotebacteria class by means of the 16S rRNA housekeeping gene. Complete sequences of the gene have been retrieved from the NCBI public database. In the experimental tests the maps show clusters of homologous type strains and present some singular cases potentially due to incorrect classification or erroneous annotations in the database

Dietary patterns in infancy and cognitive and neuropsychological function in childhood

Trials in developing countries suggest that improving young children's diet may benefit cognitive development. Whether dietary composition influences young children's cognition in developed countries is unclear. Although many studies have examined the relation between type of milk received in infancy and subsequent cognition, there has been no investigation of the possible effect of variations in the weaning diet

What are the living conditions and health status of those who don't report their migration status? a population-based study in Chile

BACKGROUND: Undocumented immigrants are likely to be missing from population databases, making it impossible to identify an accurate sampling frame in migration research. No population-based data has been collected in Chile regarding the living conditions and health status of undocumented immigrants. However, the CASEN survey (Caracterizacion Socio- Economica Nacional) asked about migration status in Chile for the first time in 2006 and provides an opportunity to set the base for future analysis of available migration data. We explored the living conditions and health of self-reported immigrants and respondents who preferred not to report their migration status in this survey. METHODS: Cross-sectional secondary analysis of CASEN survey in Chile in 2006. Outcomes: any disability, illness/accident, hospitalization/surgery, cancer/chronic condition (all binary variables); and the number of medical/emergency attentions received (count variables). Covariates: Demographics (age, sex, marital status, urban/rural, ethnicity), socioeconomic status (education level, employment status and household income), and material standard of living (overcrowding, sanitation, housing quality). Weighted regression models were estimated for each health outcome, crude and adjusted by sets of covariates, in STATA 10.0. RESULTS: About 1% of the total sample reported being immigrants and 0.7% preferred not to report their migration status (Migration Status - Missing Values; MS-MV). The MS-MV lived in more deprived conditions and reported a higher rate of health problems than immigrants. Some gender differences were observed by health status among immigrants and the MS-MV but they were not statistically significant. Regressions indicated that age, sex, SES and material factors consistently affected MS-MVs’ chance of presenting poor health and these patterns were different to those found among immigrants. Great heterogeneity in both the MS-MV and the immigrants, as indicated by wide confidence intervals, prevented the identification of other significantly associated covariates. CONCLUSION: This is the first study to look at the living conditions and health of those that preferred not to respond their migration status in Chile. Respondents that do not report their migration status are vulnerable to poor health and may represent undocumented immigrants. Surveys that fail to identify these people are likely to misrepresent the experiences of immigrants and further quantitative and qualitative research is urgently required