Efficient tilings of de Bruijn and Kautz graphs

Kautz and de Bruijn graphs have a high degree of connectivity which makes them ideal candidates for massively parallel computer network topologies. In order to realize a practical computer architecture based on these graphs, it is useful to have a means of constructing a large-scale system from smaller, simpler modules. In this paper we consider the mathematical problem of uniformly tiling a de Bruijn or Kautz graph. This can be viewed as a generalization of the graph bisection problem. We focus on the problem of graph tilings by a set of identical subgraphs. Tiles should contain a maximal number of internal edges so as to minimize the number of edges connecting distinct tiles. We find necessary and sufficient conditions for the construction of tilings. We derive a simple lower bound on the number of edges which must leave each tile, and construct a class of tilings whose number of edges leaving each tile agrees asymptotically in form with the lower bound to within a constant factor. These tilings make possible the construction of large-scale computing systems based on de Bruijn and Kautz graph topologies.Comment: 29 pages, 11 figure

Admission hyperglycaemia as a prognostic indicator of outcome in major trauma patients at Bugando Medical Centre, Mwanza, Tanzania

Background: Admission hyperglycemia has been reported to be associated with poor outcomes among patients with major trauma. However, most of the available literature on this subject has been conducted in the developed world. This study aimed to determine the association between admission hyperglycemia and the outcome of major trauma patients admitted to Bugando Medical Centre. Methods: This was a prospective cohort study, involving major trauma patients admitted to Bugando Medical Centre (BMC) within 6 months from Sept 2017 to February 2018. The exposure was admission hyperglycemia (>11.1mmol/l) and non-exposure was normoglycemia (≤11.1mmol/l). Results:  A total of 217 patients (M: F ratio = 4.1: 1) were recruited. Their ages ranged from 4 to 97 years with a median age of 31 years. Out of 217 patients, 106 (48.8%) were hyperglycemic and the remaining 111(51.2%) were normoglycemic. The overall median days of length of hospital stay (LOS) was 15 days. There was no statistically significant association between admission hyperglycemia and LOS (p =0.875). In this study, 73 patients died giving a mortality of 33.6%. Patients with admission hyperglycemia (>11.1mmol/l) had significantly higher mortality as compared to normoglycemic patients (≤11.1mmol/l) (p < 0.001). Conclusion: This study found that admission hyperglycemia was statistically significantly associated with increased mortality among major trauma patients at BMC. Therefore, there is a need to institute regular monitoring of blood sugar levels among these patients and give appropriate treatment to those found with elevated blood sugar levels

Profile of technical support requests in the context of the maintenance of the Brazilian network of institutional repositories and local digital libraries of theses and dissertations

We present a qualitative and quantitative analysis of the profile of requests for technological support to institutions and users in Brazilian networks of open access scientific resources that are supported by IBICT. The information collected was based on a system of control of requests for assistance (Trello), which was adopted in September 2016. The results obtained point to the development of strategies and tools that lead to a greater efficiency in the use of time resources specialized support staff within the institutions

Diagnostic value of pneumoperitoneum on plain abdominal film in patients with suspected visceral perforation at Bugando Medical Centre, Mwanza, Tanzania

Background:  The presence of pneumoperitoneum on plain abdominal film has been widely used in many centres in Tanzania as primary diagnostic imaging in patients with suspected visceral perforation. However, its diagnostic value has not yet been assessed in any hospital in the country including Bugando Medical Centre (BMC), and therefore its use as a diagnostic tool in these patients is not justified. This existing knowledge gap prompted the author to conduct this study. The study aimed to determine the diagnostic value of pneumoperitoneum on plain abdominal film in patients with suspected visceral perforation in our local setting. Methods: This was a prospective cross-sectional study among patients with suspected visceral perforation at BMC from June 2017 to May 2018. Pneumoperitoneum on plain abdominal radiography was evaluated, and the findings were cross-tabulated against operative findings, the gold standard. Then, the sensitivity, specificity, accuracy, Positive Predictive Value, Negative Predictive Value and accuracy were calculated to determine the diagnostic value of pneumoperitoneum on plain abdominal film. The Kappa statistic (қ) was calculated to determine the degree of agreement with operative findings. Results: A total of 132 patients were studied. The median age of patients was 35 years. The diagnostic accuracy of pneumoperitoneum on plain abdominal film in the detection of perforation was 90.9% with sensitivity, specificity, PPV and NPV of 90.1%, 92.7%, 96.5% and 80.9% respectively. There was good agreement with operative findings (κ = 0.86). The perforations of the ileum, gastric, duodenum, colon and appendix accounted for 36.3%, 22.0%, 19.8%, 11.0% and 11.0% of cases, respectively. The sensitivity, specificity, PPV, NPV and accuracy perforations of the ileum, gastric, duodenum, colon and appendix were 61.5-100%, 31.7-46.5%, 10.6-37.7%, 85.1-100% and 38.6-59.1% respectively.  The kappa statistics showed good agreement with the operative findings (ķ = 0.76-0.89). Conclusion: The presence of pneumoperitoneum on plain abdominal film provides high diagnostic value in the detection of visceral perforation and can be employed at BMC to improve the diagnostic value in patients with suspected visceral perforation and subsequently reduce negative laparotomy and complication rates

Patterns of surgical admissions among geriatric patients admitted to Bugando Medical Centre, Mwanza, Tanzania

Background: Surgery in geriatric patients constitutes a major but neglected public health problem. It hence poses a great challenge to surgeons and general practitioners practising in a resource-limited setting. Geriatric patients are increasingly hospitalized in surgical wards in Tanzania and little information is currently available on this group of patients. This study aimed to determine the pattern of diseases and clinical outcomes among geriatric surgical patients at Bugando Medical Centre and to identify the predictors of outcomes among these patients in our local setting. Methods and Patients: It was a cross-sectional study of geriatric surgical patients admitted to BMC from June 2017 to April 2018. Results: Out of 304 geriatric surgical patients enrolled, males outnumbered females by a male to female ratio of 3.1: 1. The majority of patients were in the 7th decade of life.  Associated medical comorbidities were reported in 107 (35.2%) patients. Urology speciality had the highest number of geriatric patients (101; 60.2%) admitted to BMC followed by general surgery in 70 (23.0%) patients. Gynaecology and Neurosurgery had the least number of geriatric patients with 4(1.3%) and 1(0.3%) patients admitted respectively. The majority of geriatric surgical patients, 286(94.1%) were treated surgically. A total of 168 patients (58.7%) developed postoperative complications. The mortality rate was 15.2% and it was significantly associated with loa ng duration of illness, high American Society of Anesthesiologist class, operation under gene anaesthesia and prolonged duration of the operation. Conclusion: This study demonstrated that surgeries among geriatric patients are commonly performed at BMC and are associated with unacceptably high morbidity and mortality. Factors responsible for the high morbidity and mortality in our geriatric surgical patients should be addressed to improve the surgical outcomes in this group of patients

HIV seroprevalence, clinical profile and surgical outcomes among patients with acquired anorectal conditions in two referral hospitals in Mwanza, Tanzania

Background: HIV infection, a major health problem worldwide, has been reported to be prevalent in patients with acquired anorectal conditions. There is a paucity of prospective studies regarding acquired anorectal conditions in Tanzania. This study describes the HIV seroprevalence, clinical profile and surgical outcomes among patients with acquired anorectal conditions at Bugando Medical Centre (BMC) and Sekou-Toure Referral Regional Hospital (SRRH). Methods: This was a cross-sectional study that was conducted among patients with acquired anorectal conditions as seen at BMC and SRRH from January 2019 to June 2019. Results:  A total of 389 patients (M: F ratio = 1.5:1) were studied. The median age at diagnosis was 42 years. Out of 389 patients, 101(26.0%) were HIV positive. Of these, 54(53.5%) were males and 47 (46.5%) were females. Haemorrhoids were the most common acquired anorectal disease accounting for 50.9% of cases. The rate of HIV infection in this study was significantly high in patients with hemorrhoids (p< 0.001), perianal ulcers (p< 0.001), anorectal abscess (p = 0.009), perianal warts (p< 0.001) and rectal prolapse (p = 0.023). A total of 173 (44.5%) patients underwent surgical treatment for acquired anorectal conditions. Hemorrhoidectomy was the most commonly performed surgical procedure in 95(54.9%) patients. Out of 171 patients who underwent surgical treatment and outcomes evaluated, 138 were treated successfully giving an overall success rate of 80.7%.  The success rate was significantly influenced by HIV positivity (p = 0.002). Surgical site infection (SSI) was the most common postoperative complication accounting for 25.8% of cases. The rate of SSI was found to be significantly higher in HIV-positive patients than in HIV-negative patients (39.6% vs 18.5%; p-value = 0.001). Conclusion: HIV infection is prevalent among patients with acquired anorectal conditions in our setting and influences surgical outcomes. We recommend that all patients with acquired anorectal conditions in this region should be screened for HIV infection

"He was shot because america will not give up on racism":Martin Luther King Jr. And the african american civil rights movement in British schools

This article examines how Martin Luther King Jr. and the movement with which he is often synonymous are taught in UK schools, as well as the consequences of that teaching for twenty-first-century understandings of Britain's racial past and present. The UK's King-centric approach to teaching the civil rights movement has much in common with that in the US, including an inattention to its transnational coordinates. However, these shared (mis)representations have different histories, are deployed to different ends, and have different consequences. In the UK, study of the African American freedom struggle often happens in the absence of, and almost as a surrogate for, engagement with the histories of Britain's own racial minorities and imperial past. In short, emphasis on the apparent singularity of US race relations and the achievements of the mid-twentieth-century African American freedom struggle facilitates cultural amnesia regarding the historic and continuing significance of race and racism in the UK. In light of the Windrush scandal and the damning 2018 Royal Historical Society report on “Race, Ethnicity and Equality in UK History,” this article argues both for better, more nuanced and more relevant teaching of King and the freedom struggle in British schools, and for much greater attention to black British history in its own right

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns