Modifiable risk of breast cancer in Northeast Iran: Hope for the future. a case-control study

Background: Breast cancer is the most common cancer in women. Its prevalence is increasing annually by 2. The determination of modifiable risk factors has been the subject of various studies. The aim of this study was to determine risk factors of breast cancer in women in Golestan Province. Patients and Methods: This case-control study was conducted among women with breast cancer recorded in the cancer registry system between 2004 and 2006 (n = 134), and their agematched healthy neighbors (n = 133). Data were statistically analyzed. Results: Age at marriage, menarche and pregnancy, breast feeding, positive family history, marital status, and educational level were not significantly correlated with risk of breast cancer, but age at menopause (< 46.6 years) was significantly correlated (95 confidence interval 1.15-7.37; p = 0.021). Live births, still births, and infant deaths were not significantly different between the 2 groups. For other variables, such as smoking history, no odds ratio was calculated. Conclusion: Results show that there is no significant correlation between variables and risk of breast cancer in our population, except for age at menopause. A large cohort study is recommended. © 2011 S. Karger GmbH, Freiburg

Nonlinear Time-Domain Analysis of a Sliding Block on a Plane

A time domain finite difference numerical model of a sliding rigid block on a plane is developed using a simple elastic-perfectly plas-tic Mohr-Coulomb interface model. The model is shown to accurately predict the slip-stick and slip-slip behavior deduced from an analytical solution for behavior of a sliding block on a horizontal plane and the results of physical model tests of a block on both hori-zontal and inclined planes subject to harmonic and non-uniform excitation provided the appropriate interface strength is employed. Back analyses of the physical model tests show that for some geosynthetic interfaces, the interface shear strength depends upon the velocity of sliding. The numerical model developed herein provides a basis for rigorous evaluation of several important problems in geotechnical earthquake engineering, including the cumulative permanent seismic deformation of landfills, embankments, slopes, and retaining walls and the stresses induced by seismic loading in geosynthetic elements of landfill liner and cover systems

Institutional Change in the Syrian Rangelands

Summaries During the past forty years, the Syrian rangelands have been the focal point of government interventions. These had four major components: assertion of state ownership over rangelands, settlement and transformation of herders into farmers, formal reorganization of the Bedouin population into range improvement and sheep husbandry cooperatives, and development of rangeland reserves. Each of these interventions has had many implications for livestock production, on rangeland management as well as on the livelihood strategies of herding households and communities. In 1994, the Syrian government took a major decision by banning cultivation in rangelands and committed itself to enhancing livestock production through better conservation, improvement and management of rangeland resources. The ban on cultivation, which is transforming sheep production systems and livelihood strategies of herding communities, is forcing herding communities to devise new strategies for overcoming their production constraints. Under present range conditions, it is clear that herding communities cannot stay there all year round and have, necessarily, to seek alternative feed resources. This article asks the questions: are herding communities likely to revert to old Bedouin livestock production systems based on trans?humance and reciprocity or will they opt to use more individualistic and market?based feed resources? Are feed access strategies differentiated by livestock ownership? How will these changes affect their production systems and livelihood strategies

Teacher’s Questioning Effects on Students Communication in Classroom Performance

Classroom questioning has been more of a puzzle regarding its role in learning output among school students. Research studies point to its significance in affecting students’ performance and achievement. The purpose of this study is to investigate how students perceive teachers’ questions in the classroom and relate them to their academic participation. The study also inquires question-types that are more or less favorably received and their consequences. The study is conducted in three schools (Grade V to VIII), and a sample of 50 students was purposively selected and interviewed through semi-structured interviews. A qualitative method is used to analyze the data; where the primary data is supported by secondary information and previous scholarly arguments. The discussion reveals that questioning in the classroom is positively associated. The study recommends that training sessions and workshops should be organized for teachers along with induction of practical courses on how to use effective questions in the classroom. Furthermore, developmental questions can be used by developmental managers in the workplace as they encourage their employees to think for themselves when taking care of customers and increasing productivity. Keywords: Teachers, classroom, questioning, high-order question, low-order question, wait time

How and Why is An Answer (Still) Correct? Maintaining Provenance in Dynamic Knowledge Graphs

Knowledge graphs (KGs) have increasingly become the backbone of many critical knowledge-centric applications. Most large-scale KGs used in practice are automatically constructed based on an ensemble of extraction techniques applied over diverse data sources. Therefore, it is important to establish the provenance of results for a query to determine how these were computed. Provenance is shown to be useful for assigning confidence scores to the results, for debugging the KG generation itself, and for providing answer explanations. In many such applications, certain queries are registered as standing queries since their answers are needed often. However, KGs keep continuously changing due to reasons such as changes in the source data, improvements to the extraction techniques, refinement/enrichment of information, and so on. This brings us to the issue of efficiently maintaining the provenance polynomials of complex graph pattern queries for dynamic and large KGs instead of having to recompute them from scratch each time the KG is updated. Addressing these issues, we present HUKA which uses provenance polynomials for tracking the derivation of query results over knowledge graphs by encoding the edges involved in generating the answer. More importantly, HUKA also maintains these provenance polynomials in the face of updates---insertions as well as deletions of facts---to the underlying KG. Experimental results over large real-world KGs such as YAGO and DBpedia with various benchmark SPARQL query workloads reveals that HUKA can be almost 50 times faster than existing systems for provenance computation on dynamic KGs

Evolution of dust in the Orion Bar with Herschel: I. Radiative transfer modelling

Interstellar dust is a key element in our understanding of the interstellar medium and star formation. The manner in which dust populations evolve with the excitation and the physical conditions is a first step in the comprehension of the evolution of inter- stellar dust. Within the framework of the Evolution of interstellar dust Herschel key program, we have acquired PACS and SPIRE spec- trophotometric observations of various photodissociation regions, to characterise this evolution. The aim of this paper is to trace the evolution of dust grains in the Orion Bar photodissociation region. We use Herschel/PACS (70 and 160 mic) and SPIRE (250, 350 and 500 mic) together with Spitzer/IRAC observations to map the spatial distribution of the dust populations across the Bar. Brightness profiles are modelled using the DustEM model coupled with a radiative transfer code. Thanks to Herschel, we are able to probe finely the dust emission of the densest parts of the Orion Bar with a resolution from 5.6" to 35.1". These new observations allow us to infer the temperature of the biggest grains at different positions in the Bar, which reveals a gradient from \sim 80 K to 40 K coupled with an increase of the spectral emissivity index from the ionization front to the densest regions. Combining Spitzer/IRAC observations, which are sensitive to the dust emission from the surface, with Herschel maps, we have been able to measure the Orion Bar emission from 3.6 to 500 mic. We find a stratification in the different dust components which can be re- produced quantitatively by a simple radiative transfer model without dust evolution. However including dust evolution is needed to explain the brightness in each band. PAH abundance variations, or a combination of PAH abundance variations with an emissivity enhancement of the biggest grains due to coagulation give good results.Comment: 11 pages, 12 figure

Physical structure of the photodissociation regions in NGC 7023: Observations of gas and dust emission with <i>Herschel</i>

The determination of the physical conditions in molecular clouds is a key step towards our understanding of their formation and evolution of associated star formation. We investigate the density, temperature, and column density of both dust and gas in the photodissociation regions (PDRs) located at the interface between the atomic and cold molecular gas of the NGC 7023 reflection nebula. We study how young stars affect the gas and dust in their environment. Our approach combining both dust and gas delivers strong constraints on the physical conditions of the PDRs. We find dense and warm molecular gas of high column density in the PDRs

Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate and low mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant HII region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset towards our side of the Large Magellanic Cloud.Comment: 20 pages, 22 Figures, 3 Tables, Photometric Catalogs and Mosaiced images will be available for download upon publication, accepted for publication on ApJ