A theoretical treatment of interval mapping of a disease gene using transmission disequilibrium tests

The genetic basis of the transmission disequilibrium test (TDT) for two-marker loci is explored from first principles. In this case, parents doubly heterozygous for a given haplotype at the pair of marker loci that are each in linkage disequilibrium with the disease gene with the further possibility of a second-order linkage disequilibrium are considered. The number of times such parents transmit the given haplotype to their affected offspring is counted and compared with the frequencies of haplotypes that are not transmitted. This is done separately for the coupling and repulsion phases of doubly heterozygous genotypes. Expectations of the counts for each of the sixteen cells possible with four-marker gametic types (transmitted vs not transmitted) are derived. Based on a test of symmetry in a square 4 × 4 contingency table, chi-square tests are proposed for the null hypothesis of no linkage between the markers and the disease gene. The power of the tests is discussed in terms of the corresponding non-centrality parameters for the alternative hypothesis that both the markers are linked with the disease locus. The results indicate that the power increases with the decrease in recombination probability and that it is higher for a lower frequency of the disease gene. Taking a pair of markers in an interval for exploring the linkage with the disease gene seems to be more informative than the single-marker case since the values of the non-centrality parameters tend to be consistently higher than their counterparts in the single-marker case. Limitations of the proposed test are also discussed

Genetic diversity - conservation and assessment

The biodiversity that we see around us is the outcome of natural evolution which has been going on for the last 3.5 billion years. However, with growing population and rapid modernization, the biodiversity is now getting depleted at an unprecedented rate. This paper examines some of the mechanisms by which the diversity, particularly at the genetic level, is maintained under natural conditions. It discusses the phenomenon of terminal extinction as well as strategies and policies for the conservation and assessment of genetic diversity

Does Disclosure Reduce Pollution? Evidence from India's Green Rating Project

Public disclosure programs that collect and disseminate information about firms’ environmental performance are increasingly popular in both developed and developing countries. Yet little is known about whether they actually improve environmental performance, particularly in the latter setting. We use detailed plant-level survey data to evaluate the impact of India’s Green Rating Project (GRP) on the environmental performance of the country’s largest pulp and paper plants. We find that the GRP drove significant reductions in pollution loadings among dirty plants but not among cleaner ones. This result comports with statistical and anecdotal evaluations of similar disclosure programs. We also find that plants located in wealthier communities were more responsive to GRP ratings, as were single-plant firms.public disclosure, pollution control, India, pulp and paper

Seroma formation after modified radical mastectomy: analysing risk factors and incidence

Background: Breast cancer is a prevalent form that affects women and is a leading cause of death among women. The development of seroma is a frequent complication that can arise after breast cancer surgery, and its underlying mechanisms are still not fully understood. Consequently, data was collected to analyze the occurrence and factors that contribute to the development of seroma in patients. We aimed to enhance our comprehension and ultimately discover methods to mitigate it. Methods: A prospective group research study was conducted on a sample of 86 female patients who underwent mastectomy from August 2020 to August 2023. This study was carried out as part of the senior residency program at Nalanda Medical College and Hospital in Patna, Bihar, India. Patients who develop seroma within four weeks of surgery are usually recommended to undergo, specifically ultrasonography, and radiological evaluation to determine the size. Results: 27 out of 86 patients (31%) were found to have seroma. Several factors are closely linked to the development of seroma. Factors that may contribute to increased risk The minimum age at which seroma production occurs following MRM ≥56 or older, having a BMI of 26.50 or higher, a tumour measuring 4 cm or larger undergoing the removal of more than 12 lymph nodes, and having a level 3 axillary dissection. Conclusions: After surgery, a certain group of people in the study experienced seroma formation within four weeks. These individuals had undergone MRM. Age, BMI, tumour size, level 3 axillary dissection, the removal of more than 12 lymph nodes during surgery, and the occurrence of seroma after MRM were found to be positively correlated. There was no observed connection between seroma production and a range of factors, such as neoadjuvant chemotherapy, the timing of drain removal, shoulder workouts, and the use of breast bandages

Intestinal obstruction caused by tuberculosis: unmasking a silent risk

Background: Intestinal tuberculosis (TB) remains a global health challenge, especially in regions with a high TB prevalence. This manifestation, distinct from pulmonary TB, involves the gastrointestinal tract, often leading to intestinal obstruction. The study addresses the insidious nature of the disease, emphasizing the urgency for timely diagnosis and intervention. Recognizing the multifaceted impact of TB on various organs, the study explores the pathophysiology, clinical presentation, and diagnostic complexities of intestinal TB. Methods: This study was conducted at Nalanda medical college and hospital in Patna, Bihar, India, the retrospective study spans three years focusing on 127 patients with intestinal obstruction due to TB. Inclusion criteria prioritized histopathological confirmation of TB, ensuring cohort accuracy. The study employed preliminary investigations, including hemogram, chest X-ray, abdominal X-ray, ultrasonogram, sputum examination, and Mantoux test and CECT whole abdomen. Clinical presentations were systematically analyzed, guiding tailored management protocols based on the mode of presentation. Results: Demographically, the study identified TB as the cause in 127 cases, with a balanced gender distribution and a peak incidence in the 21-30 years age group. Presentations varied, predominantly with acute symptoms. Common complaints included abdominal pain, vomiting, constipation, and distension. Surgical intervention within 24 hours was crucial in 61.1% of cases. Intraoperatively, findings comprised mesenteric thickening, lymph nodal enlargement, and adhesions. Adhesionolysis was the primary procedure. Postoperative complications, mainly wound infections, were noted but had a limited impact on mortality. Conclusions: This study reveals TB as a significant contributor to intestinal obstruction, emphasizing challenges in early diagnosis. Adhesionolysis emerges as a key operative procedure, underscoring the need for surgical flexibility. Postoperative complications, while notable, have minimal impact on mortality

The M Theory Five-Brane and the Heterotic String

Brane actions with chiral bosons present special challenges. Recent progress in the description of the two main examples -- the M theory five-brane and the heterotic string -- is described. Also, double dimensional reduction of the M theory five-brane on K3 is shown to give the heterotic string.Comment: 13 pages, latex, no figures; ICTP Conference Proceeding

Asymmetric Non-Abelian Orbifolds and Model Building

The rules for the free fermionic string model construction are extended to include general non-abelian orbifold constructions that go beyond the real fermionic approach. This generalization is also applied to the asymmetric orbifold rules recently introduced. These non-abelian orbifold rules are quite easy to use. Examples are given to illustrate their applications.Comment: 30 pages, Revtex 3.