143 research outputs found
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Transversals as generating sets in finitely generated groups
We explore transversals of finite index subgroups of finitely generated groups. We show that when is a subgroup of a rank- group and has index at least in , we can construct a left transversal for which contains a generating set of size for ; this construction is algorithmic when is finitely presented. We also show that, in the case where has rank , there is a simultaneous left–right transversal for which contains a generating set of size for . We finish by showing that if is a subgroup of a rank- group with index less than , and contains no primitive elements of , then is normal in and .This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/S000497271500098
Autosomal recessive and sporadic non syndromic hearing loss and the incidence of Cx26 mutations in a province of Iran
Despite the enormous heterogeneity of genetic hearing loss, mutations in the GJB2 (connexin 26) gene located on "DFNB1" locus (13q12) account for up to 50 of cases of autosomal recessive non-syndromic hearing loss (ARNSHL) in some populations. This study describes the analysis of 100 autosomal recessive and sporadic nonsyndromic hearing loss individuals from 79 families each having at least one deaf child in Chehar Mahal va Bakhtiari province in west of Iran. We have investigated the prevalence of the connexin 26 gene mutations using nested PCR strategy to screen the predominant 35delG mutation and subsequent direct sequencing to detect other Cx26 mutations. Seven different genetic variants were detected from which one novel variant was including 363delC. The 35delG was the most common mutation found in 5 of 79 families (6.3). Cx26 related deafness mutations (35delG,V27I; E114G) and R127H) were found in 12 of 158 chromosomes studied (7.8%). We conclude that the association of Cx26 mutations with deafness in Chehar Mahal va Bakhtiari province is low and looks like most other populations of Iran
The Human Ecology and Geography of Burning in an Unstable Savanna Environment
According to new ecological theories, many savannas are inherently in disequilibrium and can flip from tree-dominated to grass-dominated landscapes depending upon the disturbance regime. In particular, a shift in a fire regime to a more frequent and intensive one can radically alter the tree-to-grass ratio in a given savanna. Drawing upon the ecological buffering model we argue that savanna persistence requires a relatively stable fire regime. We hypothesize that anthropogenic burning practices perform this function by producing a regular annual spatiotemporal pattern of fire that is linked to vegetation type. We test this hypothesis using a study of two areas, one in Mali and the other Burkina Faso. We use two sources of satellite data to produce an 11-year time series of the spatiotemporal pattern of fires and an example of the annual burned area pattern these fires produce. We combine the analysis of satellite imagery with interviews of rural inhabitants who set fires to understand the logic underlying the patterns of fire. Analysis of a time series of imagery reveals a strikingly regular annual spatiotemporal pattern of burning for both study areas, which cannot be explained by the regional climatic pattern alone. We conclude that the regularity of the annual fire regime in West Africa is a human-ecological phenomenon closely linked to vegetation type and controlled by people\u27s burning practices. We argue that the anthropogenic burning regime serves to buffer the savanna and maintain its ecological stability
Molecular detection of prostate specific antigen in patients with prostate cancer or benign prostate hyperplasia the first investigation from Iran
Prostate cancer is the second common form of cancer in men. Detection of circulating Prostate Specific Antigen (PSA) transcripts has effectively been used for early diagnosis of prostate cancer cells. This investigation employed a reverse transcriptase polymerase chain reaction (RT-PCR) technique to distinguish the patients with either localized or metastatic prostate cancer (CaP) vs. Benign Prostate Hyperplasia (BPH) and control subjects, as compared with clinical and pathological records. With reservation of ethical issues, blood samples were collected from 60 cases. Based on pathological and clinical findings, 25 patients (20 with localized cancer, 5 with metastatic), 22 with BPH, and 13 healthy (including 3 females) subjects as negative controls, were selected from Shariati, Mehrad, Sina,, Khatam and Atie Hospitals in Tehran, Iran. RT-PCR for a 260 bp PSA transcript was then performed. Clinical and pathological records were used for the assessment and comparison of PSA RT-PCR results. None of the control subjects and BPH (with 7 exceptions) were found positive by RT-PCR (Relative specificity= 72.7). In patients with prostate cancer, 21 out of 25 were found PSA positive (Relative sensitivity= 83.4) and the remaining 3 have been shown to be PSA negative (Positive predictive value= 83.4). All of 5 metastatic patients (100) revealed PSA positive results. Our data reflects the clinical relevance and significance of RT-PCR results as assessed with clinical and pathological examinations. PSA RT-PCR might be used as a powerful means for diagnosis, even when either pathological or clinical findings are negative, and could be employed for further molecular epidemiology surveys
“Try, Try, Try Again:” Sequence Analysis of User Interaction Data with a Voice User Interface
Global burned area and biomass burning emissions from small fires
[1] In several biomes, including croplands, wooded savannas, and tropical forests, many small fires occur each year that are well below the detection limit of the current generation of global burned area products derived from moderate resolution surface reflectance imagery. Although these fires often generate thermal anomalies that can be detected by satellites, their contributions to burned area and carbon fluxes have not been systematically quantified across different regions and continents. Here we developed a preliminary method for combining 1-km thermal anomalies (active fires) and 500 m burned area observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate the influence of these fires. In our approach, we calculated the number of active fires inside and outside of 500 m burn scars derived from reflectance data. We estimated small fire burned area by computing the difference normalized burn ratio (dNBR) for these two sets of active fires and then combining these observations with other information. In a final step, we used the Global Fire Emissions Database version 3 (GFED3) biogeochemical model to estimate the impact of these fires on biomass burning emissions. We found that the spatial distribution of active fires and 500 m burned areas were in close agreement in ecosystems that experience large fires, including savannas across southern Africa and Australia and boreal forests in North America and Eurasia. In other areas, however, we observed many active fires outside of burned area perimeters. Fire radiative power was lower for this class of active fires. Small fires substantially increased burned area in several continental-scale regions, including Equatorial Asia (157%), Central America (143%), and Southeast Asia (90%) during 2001–2010. Globally, accounting for small fires increased total burned area by approximately by 35%, from 345 Mha/yr to 464 Mha/yr. A formal quantification of uncertainties was not possible, but sensitivity analyses of key model parameters caused estimates of global burned area increases from small fires to vary between 24% and 54%. Biomass burning carbon emissions increased by 35% at a global scale when small fires were included in GFED3, from 1.9 Pg C/yr to 2.5 Pg C/yr. The contribution of tropical forest fires to year-to-year variability in carbon fluxes increased because small fires amplified emissions from Central America, South America and Southeast Asia—regions where drought stress and burned area varied considerably from year to year in response to El Nino-Southern Oscillation and other climate modes
Influence of parent-adolescent relationship on early sexual debut and number of partners among Mexican youth
Objective: To evaluate whether parents-adolescents relationship was associated with early sexual debut and having multiple partners in a low socioeconomic suburb in Mexico City.
Methods: An anonymous questionnaire about sexual activity and relationships with parents during adolescence was responded by 936 participants, aged 20-30. Logistic regression was conducted.
Results: The majority of participants reported being sexually active (78.3%). Among them, 70% of males and 55% of females had first sex before age 18. Good communication with parents during adolescence was inversely associated with sexual debut 2 sexual partners (OR=0.47; IC95% 0.33-0.68). Sexual debut <18 was associated with having had multiple partners (OR=3.86; IC95% 2.60-5.73).
Conclusion: Good parental communication during adolescence may help prevent adolescents from choosing early sexual debut and having multiple partners and, consequently, from acquiring sexually transmitted diseases. Efforts are necessary to support parents in their relationship with their adolescent children
Religious affiliation modulates weekly cycles of cropland burning in Sub-Saharan Africa
Research ArticleVegetation burning is a common land management practice in Africa, where fire is used
for hunting, livestock husbandry, pest control, food gathering, cropland fertilization, and
wildfire prevention. Given such strong anthropogenic control of fire, we tested the hypotheses
that fire activity displays weekly cycles, and that the week day with the fewest fires
depends on regionally predominant religious affiliation.We also analyzed the effect of land
use (anthrome) on weekly fire cycle significance. Fire density (fire counts.km-2) observed
per week day in each region was modeled using a negative binomial regression model, with
fire counts as response variable, region area as offset and a structured random effect to
account for spatial dependence. Anthrome (settled, cropland, natural, rangeland), religion
(Christian, Muslim, mixed) week day, and their 2-way and 3-way interactions were used as
independent variables. Models were also built separately for each anthrome, relating
regional fire density with week day and religious affiliation. Analysis revealed a significant
interaction between religion and week day, i.e. regions with different religious affiliation
(Christian, Muslim) display distinct weekly cycles of burning. However, the religion vs. week
day interaction only is significant for croplands, i.e. fire activity in African croplands is significantly
lower on Sunday in Christian regions and on Friday in Muslim regions. Magnitude of
fire activity does not differ significantly among week days in rangelands and in natural
areas, where fire use is under less strict control than in croplands. These findings can contribute
towards improved specification of ignition patterns in regional/global vegetation fire
models, and may lead to more accurate meteorological and chemical weather forecastinginfo:eu-repo/semantics/publishedVersio
Rural Livelihoods and Burning Practices in Savanna Landscapes of Nusa Tenggara Timur, Eastern Indonesia
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