The Cowl - v.11 - n.5 - Nov 10, 1948

The Cowl - student newspaper of Providence College. Volume 11, Number 5 - November 10, 1948. 6 pages

Document Type De�nition (DTD) Metrics

In this paper, we present two complexity metrics for the assessment of schema quality written in Document Type De�finition (DTD) language. Both "Entropy (E) metric: E(DTD)" and "Distinct Structured Element Repetition Scale (DSERS) metric: DSERS(DTD)" are intended to measure the structural complexity of schemas in DTD language. These metrics exploit a directed graph representation of schema document and consider the complexity of schema due to its similar structured elements and the occurrences of these elements. The empirical and theoretical validations of these metrics prove the robustness of the metrics

Genetic diversity and population structure of Peronosclerospora sorghi isolates of Sorghum in Uganda

Sorghum is the third most important staple cereal crop in Uganda after maize and millet. Downy mildew disease is one of the most devastating fungal diseases which limits the production and productivity of the crop. The disease is caused by an obligate fungus, Peronosclerospora sorghi (Weston & Uppal) with varying symptoms. Information on the genetic diversity and population structure of P.sorghi in sorghum is imperative for the screening and selection for resistant genotypes and further monitoring possible mutant(s) of the pathogen. Isolates of P. sorghi infecting sorghum are difficult to discriminate when morphological descriptors are used. The use of molecular markers is efficient, and reliably precised for characterizing P. sorghi isolates. This study was undertaken to assess the level of genetic diversity and population structure that exist in P. sorghi isolates in Uganda. A total of 195 P. sorghi isolates, sampled from 13 different geographic populations from 10 different regions (agro-ecological zones) was used. Eleven (11) molecular markers, comprising of four Random amplified microsatellite (RAM) and seven (7) Inter-Simple Sequence Repeat (ISSR) markers were used in this study. The analysis of molecular variation (AMOVA) based on 11 microsatellite markers showed significant (P < 0.001) intra-population (88.9 %, PhiPT = 0.111) and inter-population (8.4 %, PhiPR = 0.083) genetic variation, while the genetic variation among regions (2.7 %, PhiRT = 0.022) was not significant. The highest genetic similarity value (0.987 = 98.7 %) was recorded between Pader and Lira populations and the lowest genetic similarity (0.913 = 91.3 %) was observed between Namutumba and Arua populations. The mean Nei's genetic diversity index (H) and Shannon Information Index (I) were 0.308 and 0.471 respectively. Seven distinct cluster groups were formed from the 195 P. sorghi isolates based on their genetic similarity. Mantel test revealed no association between genetic differentiation and geographical distance (R2 = 0.0026, p = 0.02) within the 13 geographic populations

Phylogenetic relationships of eleven Kobresia accessions from the Tibetan plateau

In the past, identification of the genus Kobresia was mostly dependent on morphological characteristics. This study used random amplified polymorphic DNA (RAPD), sequences of nrDNA ITS, cpDNA trnT-L-F spacer and cpDNA ndhF to assess the phylogenetic relationships among the accessions of Kobresia plants collected from the Tibetan plateau. In the dendrograms, Kobresia macrentha (L) species formed a separate clade suggesting a remote relationship with other accessions. These trees showed that species found in similar habitats or having similar adaptations tended to cluster together. Thus, the genetic variation and adaptation seen in these Kobresia accessions may be due to their remote geographic and high altitudinal position in the Tibetan plateau. This study highlights the importance of molecular analysis in understanding the genetic diversity and structure of Kobresia accessions, and contributes to the knowledge of conservation of genetic resources

Diarrhea as a potential cause and consequence of reduced gut microbial diversity among undernourished children in Peru

BACKGROUND: Detrimental effects of diarrhea on child growth and survival are well documented, but details of the underlying mechanisms remain poorly understood. Recent evidence demonstrates that perturbations to normal development of the gut microbiota in early life may contribute to growth faltering and susceptibility to related childhood diseases. We assessed associations between diarrhea, gut microbiota configuration, and childhood growth in the Peruvian Amazon. METHODS: Growth, diarrhea incidence, illness, pathogen infection, and antibiotic exposure were assessed monthly in a birth cohort of 271 children aged 0-24 months. Gut bacterial diversity and abundances of specific bacterial taxa were quantified by sequencing 16S rRNA genes in fecal samples collected at 6, 12, 18, and 24 months. Linear and generalized linear models were used to determine whether diarrhea was associated with altered microbiota and, in turn, if features of the microbiota were associated with the subsequent risk of diarrhea. RESULTS: Diarrheal frequency, duration, and severity were negatively associated with bacterial diversity and richness (P \u3c .05). Children born stunted (length-for-age z-score [LAZ] ≤ -2) who were also severely stunted (LAZ ≤ -3) at the time of sampling exhibited the greatest degree of diarrhea-associated reductions in bacterial diversity and the slowest recovery of bacterial diversity after episodes of diarrhea. Increased bacterial diversity was predictive of reduced subsequent diarrhea from age 6 to 18 months. CONCLUSIONS: Persistent, severe growth faltering may reduce the gut microbiota\u27s resistance and resilience to diarrhea, leading to greater losses of diversity and longer recovery times. This phenotype, in turn, denotes an increased risk of future diarrheal disease and growth faltering

Efficiency Analysis of Major Container Ports in Asia: Using DEA and Shannon’s Entropy

This paper attempts to evaluate performance (i.e. efficiency) of Asias container ports. Measurement of the ports performance is critical to increase the competitiveness of maritime transport, ultimately leading to one nations competitive advantages over other countries. Data Envelopment Analysis (DEA), which is a non-parametric method widely used for assessing efficiency of units which have similar characteristics, was selected to analyse the data. Due to the limitations of the DEA method producing diverse results according to different models, and to the complexities of choosing a specific model among several DEA models, Shannons Entropy was also employed. By including Shannons Entropy, the efficiency results calculated from each model were integrated in order to rank the ports. The results in this study will provide port managers with valuable information in order to understand the current status of Asias container ports in terms of their efficiency

Sorting Methods in Self-Organization of Models and Clusterizations (Review of New Basic Ideas) - Iterative (Multirow) Polynomial GMDH Algorithms

Review of the Group Method of Data Handling approac

Riparian corridor vegetation structure and soil function along urban, suburban, and rural streams in Louisville, KY, USA.

Stream riparian zones are ecotones between terrestrial and aquatic environments. Studying these areas in urban environments is important since they lie adjacent to stream water supplies. I conducted a study of riparian woody and groundcover vegetation along urban, suburban, and rural streams (land-use designations based on % impervious surface) to assess how cities are affecting plant community structure. I also studied riparian soil gas flux (carbon dioxide, methane, and nitrous oxide) in relation to water table depth and groundwater nutrient concentrations spanning a 10-month period (January to October, 2008). I found distinct woody and groundcover communities associated with proportion of impervious surface surrounding the research sites. These communities differed regarding diversity and proportion of native, exotic, and wetland species distributions. The most urban communities generally had lower species richness, more exotic species, and fewer wetland species when compared to rural areas. Urban areas also exhibited the highest streambanks and lowest water tables. Carbon dioxide gas flux rates were higher in urban areas, but methane and nitrous oxide fluxes did not respond uniformly to site differences as classified by proportion of impervious surface. Methane and nitrous oxide differences, in addition to seasonal variability, were more greatly affected by local site level differences in substrate and nutrient ratios as well as soil moisture