Finite semifields and their applications

This thesis is concerned with finite semi fields. The objective of this thesis is to give a full description of Knuth orbits of known commutative semi fields. We also describe planar functions corresponding to commutative semi fields. Results are presented by tables. Nuclei of semi fields are studied. Finally we consider applications of semi fields, planar functions and spreads to construction of mutually unbiased bases

Seasonality of COVID-19 incidence in the United States

BackgroundThe surges of Coronavirus Disease 2019 (COVID-19) appeared to follow a repeating pattern of COVID-19 outbreaks regardless of social distancing, mask mandates, and vaccination campaigns.ObjectivesThis study aimed to investigate the seasonality of COVID-19 incidence in the United States of America (USA), and to delineate the dominant frequencies of the periodic patterns of the disease.MethodsWe characterized periodicity in COVID-19 incidences over the first three full seasonal years (March 2020 to March 2023) of the COVID-19 pandemic in the USA. We utilized a spectral analysis approach to find the naturally occurring dominant frequencies of oscillation in the incidence data using a Fast Fourier Transform (FFT) algorithm.ResultsOur study revealed four dominant peaks in the periodogram: the two most dominant peaks show a period of oscillation of 366 days and 146.4 days, while two smaller peaks indicate periods of 183 days and 122 days. The period of 366 days indicates that there is a single COVID-19 outbreak that occurs approximately once every year, which correlates with the dominant outbreak in the early/mid-winter months. The period of 146.4 days indicates approximately 3 peaks per year and matches well with each of the 3 annual outbreaks per year.ConclusionOur study revealed the predictable seasonality of COVID-19 outbreaks, which will guide public health preventative efforts to control future outbreaks. However, the methods used in this study cannot predict the amplitudes of the incidences in each outbreak: a multifactorial problem that involves complex environmental, social, and viral strain variables

Effect montmorillonite clay as aggregate in lightweight concrete cement-free

Light weight concrete has many advantages that can be used in the construction of buildings. Perhaps one of the most important of these features is its light weight, which contributes a lot to reducing stress on the soil, which provides the possibility of rising buildings and increasing the number of floors. In addition to its role in thermal insulation and its impact on reducing the consumption of energy sources in cooling and heating, light weight concrete is considered one of the sustainability factors in buildings. One of the second major factors in sustainability is to reduce or avoid the use of cement in the manufacture of this concrete, because of the harmful effects of cement on the environment and global warming. Cement-free concrete is considered a sustainable material in terms of its depletion of the waste materials and spin-off products from different industries apposite of consumption of natural resources in the cement industry (mud, limestone). In this research first aim is to produce lightweight cement-free concrete using pozolanic material and montmorillonite clay as coarse and fine aggregate. Studying some properties of producing light weight concrete (density, compression, tensile,) with different ages (7, 28, 56) days

Leaving Against Medical Advice Among Patients With Brain Tumours in the Middle East: Khoula Hospital Experience

Background: Leaving against medical advice (LAMA) can be defined broadly as a patient’s insistence upon leaving the hospital against the treating team has expressed advice, which is both a challenge and concern for physicians, as these patients lost to follow-up, and their outcomes remain unknown. There is no previous study conducted to find the prevalence and causes of LAMA in brain tumors patients in the Middle East to the best of our knowledge.Methods: Patients studied in this research are those who were diagnosed with any type of brain tumors and were admitted to the Neurosurgical Department in Khoula Hospital (KH) but signed LAMA in the two years between January 2017 to December 2018 by going through the electronic medical records. Data obtained from the health information system includes socioeconomic characteristics, health status-related data, diagnosis-related data, and the reasons for LAMA.Results: A total number of 302 patients with brain tumors included in this study. Twenty-eight patients (9.2%) signed LAMA with a majority of those who signed LAMA were in the young adult’s group (3-39 years) and represented 18 (64%). Eight patients (28.57%) among the LAMA group and 43 patients (15.69%) in the non-LAMA group have tumors in the frontal lobe, which has found to be the most familiar location (29%). There was a significant relationship between the reason for LAMA and gender (P = 0.020).Conclusion: Younger patients, male, Omani, newly diagnosed tumors, and tumors in the frontal lobe were all risk factors for LAMA. Education and awareness about LAMA recommended in order to avoid readmission and loss of follow up

Development and Testing of A Wearable Vibrotactile Haptic Feedback System For Proprioceptive Rehabilitation

The human sense of touch is an integral part of daily life. For tasks involving grasping and manipulation of objects, force feedback is a key requirement. Most of the systems give contact point or complete grasping force feedback; for precision grasping and other physical interactions, finger awareness and force feedback from independent fingers is essential. In this study a novel, wearable proprioceptive rehabilitation system is designed which restores the ability of identifying and distinguishing between individual fingers of a prosthetic hand or an exoskeleton in a non-invasive manner. Moreover, it provides different levels of force feedback from every finger as well, which enables the user to distinguish and control force in precision grasping activities. For testing the system accuracy, classical psychophysical methods were used on a group of 14 voluntary disabled subjects. The tests were conducted in both, ideal and real-world conditions i.e. without and with distractions and accuracies were calculated accordingly. A p-test was also conducted to observe significance between the samples of with and without distraction datasets. The system performed with an overall accuracy of 82.04% which was well above the min. performance measure of 60%. Vi-HaB is standalone system and can be mounted on any upper limb rehabilitation (prosthesis, exoskeleton) system for finger awareness and force feedback

Assembly of Smart Microgels and Hybrid Microgels on Graphene Sheets for Catalytic Reduction of Nitroarenes

Poly (N-isopropylacrylamide-acrylic acid) [p(NIPAM-AAc)] microgel was successfully fabricated using the precipitation polymerization method. Silver (Ag) nanoparticles and graphene oxide (G) were used to fabricate the following hybrid microgels: Ag-p(NIPAM-AAc) (Ag-HMG), Ag-G-p(NIPAM-AAc) (Ag-G-HMG), and G-p(NIPAM-AAc) (G-HMG). Ag-HMG, Ag-G-HMG, and G-HMG were characterized using a Zetasizer and UV-Vis spectroscopy. The reduction of a series of different compounds with comparable and distinct chemical structures was catalyzed by synthesized Ag-HMG, Ag-G-HMG, and G-HMG hybrid microgels. The average size of Ag nanoparticles was found to be ~50 nm. Ag nanoparticles were synthesized within microgels attached to G sheets. Ag-p(NIPAM-AAc), Ag-G-p(NIPAM-AAc), and G-p(NIPAM-AAc) hybrid microgels were used for the catalytic reduction of nitroarenes and dyes. By comparing their apparent rate constant (kapp), reduction duration, and percentage reduction, the activity of HMG (hybrid microgel) as a catalyst towards different substrates was investigated. Graphene sheets play role in electron relay among Ag nanoparticles and microgels.publishedVersio

Maternal anaemia and the risk of postpartum haemorrhage: a cohort analysis of data from the WOMAN-2 trial

Background: Worldwide, more than half a billion women of reproductive age are anaemic. Each year, about 70 000 women who give birth die from postpartum haemorrhage. Almost all deaths are in low-income or middle-income countries. We examined the association between anaemia and the risk of postpartum haemorrhage. Methods: We did a prospective cohort analysis of data from the World Maternal Antifibrinolytic-2 (WOMAN-2) trial. This trial enrols women with moderate or severe anaemia giving birth vaginally in hospitals in Pakistan, Nigeria, Tanzania, and Zambia. Hospitals in each country where anaemia in pregnancy is common were identified from a network established during previous obstetric trials. Women who were younger than 18 years without permission provided by a guardian, had a known tranexamic acid allergy, or developed postpartum haemorrhage before the umbilical cord was cut or clamped were excluded from the study. Prebirth haemoglobin, the exposure, was measured after hospital arrival and just before giving birth. Postpartum haemorrhage, the outcome, was defined in three ways: (1) clinical postpartum haemorrhage (estimated blood loss ≥500 mL or any blood loss sufficient to compromise haemodynamic stability); (2) WHO-defined postpartum haemorrhage (estimated blood loss of at least 500 mL); and (3) calculated postpartum haemorrhage (calculated estimated blood loss of ≥1000 mL). Calculated postpartum haemorrhage was estimated from the peripartum change in haemoglobin concentration and bodyweight. We used multivariable logistic regression to examine the association between haemoglobin and postpartum haemorrhage, adjusting for confounding factors. Findings: Of the 10 620 women recruited to the WOMAN-2 trial between Aug 24, 2019, and Nov 1, 2022, 10 561 (99·4%) had complete outcome data. 8751 (82·9%) of 10 561 women were recruited from hospitals in Pakistan, 837 (7·9%) from hospitals in Nigeria, 525 (5·0%) from hospitals in Tanzania, and 448 (4·2%) from hospitals in Zambia. The mean age was 27·1 years (SD 5·5) and mean prebirth haemoglobin was 80·7 g/L (11·8). Mean estimated blood loss was 301 mL (SD 183) for the 8791 (83·2%) women with moderate anaemia and 340 mL (288) for the 1770 (16·8%) women with severe anaemia. 742 (7·0%) women had clinical postpartum haemorrhage. The risk of clinical postpartum haemorrhage was 6·2% in women with moderate anaemia and 11·2% in women with severe anaemia. A 10 g/L reduction in prebirth haemoglobin increased the odds of clinical postpartum haemorrhage (adjusted odds ratio [aOR] 1·29 [95% CI 1·21–1·38]), WHO-defined postpartum haemorrhage (aOR 1·25 [1·16–1·36]), and calculated postpartum haemorrhage (aOR 1·23 [1·14–1·32]). 14 women died and 68 either died or had a near miss. Severe anaemia was associated with seven times higher odds of death or near miss (OR 7·25 [95% CI 4·45–11·80]) than was moderate anaemia. Interpretation: Anaemia is strongly associated with postpartum haemorrhage and the risk of death or near miss. Attention should be given to the prevention and treatment of anaemia in women of reproductive age. Funding: The WOMAN-2 trial is funded by Wellcome and the Bill & Melinda Gates Foundation

Burden of injury along the development spectrum : associations between the Socio-demographic Index and disability-adjusted life year estimates from the Global Burden of Disease Study 2017

Background The epidemiological transition of non-communicable diseases replacing infectious diseases as the main contributors to disease burden has been well documented in global health literature. Less focus, however, has been given to the relationship between sociodemographic changes and injury. The aim of this study was to examine the association between disability-adjusted life years (DALYs) from injury for 195 countries and territories at different levels along the development spectrum between 1990 and 2017 based on the Global Burden of Disease (GBD) 2017 estimates. Methods Injury mortality was estimated using the GBD mortality database, corrections for garbage coding and CODEm-the cause of death ensemble modelling tool. Morbidity estimation was based on surveys and inpatient and outpatient data sets for 30 cause-of-injury with 47 nature-of-injury categories each. The Socio-demographic Index (SDI) is a composite indicator that includes lagged income per capita, average educational attainment over age 15 years and total fertility rate. Results For many causes of injury, age-standardised DALY rates declined with increasing SDI, although road injury, interpersonal violence and self-harm did not follow this pattern. Particularly for self-harm opposing patterns were observed in regions with similar SDI levels. For road injuries, this effect was less pronounced. Conclusions The overall global pattern is that of declining injury burden with increasing SDI. However, not all injuries follow this pattern, which suggests multiple underlying mechanisms influencing injury DALYs. There is a need for a detailed understanding of these patterns to help to inform national and global efforts to address injury-related health outcomes across the development spectrum.Peer reviewe