70 research outputs found
Deformations of modules of maximal grade and the Hilbert scheme at determinantal schemes
Let R be a polynomial ring and M a finitely generated graded R-module of
maximal grade (which means that the ideal I_t(\cA) generated by the maximal
minors of a homogeneous presentation matrix, \cA, of M has maximal codimension
in R). Suppose X:=Proj(R/I_t(\cA)) is smooth in a sufficiently large open
subset and dim X > 0. Then we prove that the local graded deformation functor
of M is isomorphic to the local Hilbert (scheme) functor at X \subset Proj(R)
under a week assumption which holds if dim X > 1. Under this assumptions we get
that the Hilbert scheme is smooth at (X), and we give an explicit formula for
the dimension of its local ring. As a corollary we prove a conjecture of R. M.
Mir\'o-Roig and the author that the closure of the locus of standard
determinantal schemes with fixed degrees of the entries in a presentation
matrix is a generically smooth component V of the Hilbert scheme. Also their
conjecture on the dimension of V is proved for dim X > 0. The cohomology
H^i_{*}({\cN}_X) of the normal sheaf of X in Proj(R) is shown to vanish for 0 <
i < dim X-1. Finally the mentioned results, slightly adapted, remain true
replacing R by any Cohen-Macaulay quotient of a polynomial ring.Comment: 24 page
Randomized Clinical Trial of Laparoscopic Versus Open Repair of the Perforated Peptic Ulcer: The LAMA Trial
Background: Laparoscopic surgery has become popular during the last decade, mainly because it is associated with fewer postoperative complications than the conventional open appr
Preconceptional smoking alters spermatozoal miRNAs of murine fathers and affects offspringâs body weight
Background
Active smoking has been reported among 7% of teenagers worldwide, with ages ranging from 13 to 15 years. An epidemiological study suggested that preconceptional paternal smoking is associated with adolescent obesity in boys. We developed a murine adolescent smoking model before conception to investigate the paternal molecular causes of changes in offspringâs phenotype.
Method
Male and female C57BL/6J mice were exposed to increasing doses of mainstream cigarette smoke (CS) from onset of puberty for 6 weeks and mated with room air (RA) controls.
Results
Thirteen miRNAs were upregulated and 32 downregulated in the spermatozoa of CS-exposed fathers, while there were no significant differences in the count and morphological integrity of spermatozoa, as well as the proliferation of spermatogonia between CS- and RA-exposed fathers. Offspring from preconceptional CS-exposed mothers had lower body weights (pâ=â0.007). Moreover, data from offspring from CS-exposed fathers suggested a potential increase in body weight (pâ=â0.062).
Conclusion
We showed that preconceptional paternal CS exposure regulates spermatozoal miRNAs, and possibly influences the body weight of F1 progeny in early life. The regulated miRNAs may modulate transmittable epigenetic changes to offspring, thus influence the development of respiratory- and metabolic-related diseases such as obesity, a mechanism that warrants further studies for elaborate explanations
Extent of exposure to environmental tobacco smoke (ETS) and its dose-response relation to respiratory health among adults
BACKGROUND: There is a dearth of standardized studies examining exposure to environmental tobacco smoke (ETS) and its relationship to respiratory health among adults in developing countries. METHODS: In 2004, the Syrian Center for Tobacco Studies (SCTS) conducted a population-based survey using stratified cluster sampling to look at issues related to environmental health of adults aged 18â65 years in Aleppo (2,500,000 inhabitants). Exposure to ETS was assessed from multiple self-reported indices combined into a composite score (maximum 22), while outcomes included both self-report (symptoms/diagnosis of asthma, bronchitis, and hay fever), and objective indices (spirometric assessment of FEV(1 )and FVC). Logistic and linear regression analyses were conducted to study the relation between ETS score and studied outcomes, whereby categorical (tertiles) and continuous scores were used respectively, to evaluate the association between ETS exposure and respiratory health, and explore the dose-response relationship of the association. RESULTS: Of 2038 participants, 1118 were current non-smokers with breath CO levels †10 ppm (27.1% men, mean age 34.7 years) and were included in the current analysis. The vast majority of study participants were exposed to ETS, whereby only 3.6% had ETS score levels †2. In general, there was a significant dose-response pattern in the relationship of ETS score with symptoms of asthma, hay fever, and bronchitis, but not with diagnoses of these outcomes. The magnitude of the effect was in the range of twofold increases in the frequency of symptoms reported in the high exposure group compared to the low exposure group. Severity of specific respiratory problems, as indicated by frequency of symptoms and health care utilization for respiratory problems, was not associated with ETS exposure. Exposure to ETS was associated with impaired lung function, indicative of airflow limitation, among women only. CONCLUSIONS: This study provides evidence for the alarming extent of exposure to ETS among adult non-smokers in Syria, and its dose-response relationship with respiratory symptoms of infectious and non-infectious nature. It calls for concerted efforts to increase awareness of this public health problem and to enforce regulations aimed at protecting non-smokers
Real-time correlation functions in the O ( N ) model from the functional renormalization group
Asthma Is a Risk Factor for Respiratory Exacerbations Without Increased Rate of Lung Function Decline:Five-Year Follow-up in Adult Smokers From the COPDGene Study
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