Transmission Rate in Partial Differential Equation in Epidemic Models

The rate at which susceptible individuals become infected is called the transmission rate. It is important to know this rate in order to study the spread and the effect of an infectious disease in a population. This study aims at providing an understanding of estimating the transmission rate from mathematical models representing the population dynamics of an infectious diseases using two different methods. Throughout, it is assumed that the number of infected individuals is known. In the first chapter, it includes historical background for infectious diseases and epidemic models and some terminology needed to understand the problems. Specifically, the partial differential equations SIR model is presented which represents a disease assuming that it varies with respect to time and a one dimensional space. Later, in the second chapter, it presents some processes for recovering the transmission rate from some different SIR models in the ordinary differential equation case, and from the PDE-SIR model using some similar techniques. Later, in the third chapter, it includes some terminology needed to understand inverse problems and Tikhonov regularization, and the process followed to recover the transmission rate using the Tikhonov regularization in the non-linear case. And finally, in the fourth chapter, it has an introduction to an optimal control method followed to use Tikhonov regularization to recover the transmission rate

Sheehan’s Syndrome: It Is Time to Become More Proactive in Identifying This Disease

Sheehan’s syndrome typically occurs as a result of ischemic pituitary necrosis due to severe postpartum hemorrhage and can present with varying degrees of pituitary insufficiency. It is more common in underdeveloped countries, and is frequently diagnosed years after delivery due to its nonspecific signs and symptoms. Failure to lactate is a common initial symptom, while many women also report amenorrhea or oligomenorrhea. This article presents a 26-year-old female with a history of hypertension, who presented to the hospital for diarrhea, vomiting, and dizziness. Her blood pressure was 80/40 mmHg, requiring aggressive fluid resuscitation, after which it remained borderline. Further testing resulted in an ACTH stimulation test with inadequate response, secondary hypothyroidism, and low prolactin. Her menstrual period could not be assessed due to daily progesterone therapy for contraception. MRI of the brain showed an empty sella, after which she was diagnosed with Sheehan’s syndrome, and started on hydrocortisone and levothyroxine

Sheehan’s Syndrome: It Is Time to Become More Proactive in Identifying This Disease

Sheehan’s syndrome typically occurs as a result of ischemic pituitary necrosis due to severe postpartum hemorrhage and can present with varying degrees of pituitary insufficiency. It is more common in underdeveloped countries, and is frequently diagnosed years after delivery due to its nonspecific signs and symptoms. Failure to lactate is a common initial symptom, while many women also report amenorrhea or oligomenorrhea. This article presents a 26-year-old female with a history of hypertension, who presented to the hospital for diarrhea, vomiting, and dizziness. Her blood pressure was 80/40 mmHg, requiring aggressive fluid resuscitation, after which it remained borderline. Further testing resulted in an ACTH stimulation test with inadequate response, secondary hypothyroidism, and low prolactin. Her menstrual period could not be assessed due to daily progesterone therapy for contraception. MRI of the brain showed an empty sella, after which she was diagnosed with Sheehan’s syndrome, and started on hydrocortisone and levothyroxine

Experiences during the first four years of a postpartum perineal clinic in the USA

ObjectiveTo assess the characteristics of patients seen at a postpartum perineal clinic in the USA during the first 4 years of its existence, and to identify factors contributing to the clinic’s success.MethodsIn a retrospective study, the charts of patients presenting to the clinic between July 1, 2007, and June 30, 2011, were reviewed for presenting complaint, findings, treatment, number of visits, and referral source. Strategies that led to successful clinic implementation were reviewed.ResultsA total of 247 patients were seen during the 4‐year period. Indications for referral included lacerations, pain, urinary and fecal incontinence, and fistulas. The most common referral indication was a third‐ or fourth‐degree laceration, which affected 154 (62.3%) patients. Overall, 53 (21.5%) patients required a procedure, of whom 20 (8.1%) underwent surgery. Most women were counseled about pelvic floor exercises, and 39 (15.8%) were referred for pelvic floor physical therapy. Nurse‐led triage, patient education, and follow‐up were key to the success of the program.ConclusionThe postpartum perineal clinic is sustainable and offers an opportunity for early assessment and treatment of pelvic floor dysfunction after a complicated vaginal delivery.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135192/1/ijgo68.pd

Measuring Coverage in MNCH:A Validation Study Linking Population Survey Derived Coverage to Maternal, Newborn, and Child Health Care Records in Rural China

Accurate data on coverage of key maternal, newborn, and child health (MNCH) interventions are crucial for monitoring progress toward the Millennium Development Goals 4 and 5. Coverage estimates are primarily obtained from routine population surveys through self-reporting, the validity of which is not well understood. We aimed to examine the validity of the coverage of selected MNCH interventions in Gongcheng County, China.We conducted a validation study by comparing women's self-reported coverage of MNCH interventions relating to antenatal and postnatal care, mode of delivery, and child vaccinations in a community survey with their paper- and electronic-based health care records, treating the health care records as the reference standard. Of 936 women recruited, 914 (97.6%) completed the survey. Results show that self-reported coverage of these interventions had moderate to high sensitivity (0.57 [95% confidence interval (CI): 0.50-0.63] to 0.99 [95% CI: 0.98-1.00]) and low to high specificity (0 to 0.83 [95% CI: 0.80-0.86]). Despite varying overall validity, with the area under the receiver operating characteristic curve (AUC) ranging between 0.49 [95% CI: 0.39-0.57] and 0.90 [95% CI: 0.88-0.92], bias in the coverage estimates at the population level was small to moderate, with the test to actual positive (TAP) ratio ranging between 0.8 and 1.5 for 24 of the 28 indicators examined. Our ability to accurately estimate validity was affected by several caveats associated with the reference standard. Caution should be exercised when generalizing the results to other settings.The overall validity of self-reported coverage was moderate across selected MNCH indicators. However, at the population level, self-reported coverage appears to have small to moderate degree of bias. Accuracy of the coverage was particularly high for indicators with high recorded coverage or low recorded coverage but high specificity. The study provides insights into the accuracy of self-reports based on a population survey in low- and middle-income countries. Similar studies applying an improved reference standard are warranted in the future

A prevalence survey of every-day activities in pregnancy

<p>Abstract</p> <p>Background</p> <p>Research into the effects of common activities during pregnancy is sparse and often contradictory. To examine whether common activities are an acute trigger of pregnancy complications the prevalence of these activities are necessary to determine sample size estimates. The aim of this study is to ascertain the prevalence of selected activities in any seven day period during pregnancy.</p> <p>Methods</p> <p>The study was conducted in the antenatal clinic of a teaching hospital with tertiary obstetric and neonatal care in Sydney, Australia between August 2008 and April 2009. Women who were at least 20 weeks pregnant and able to read English completed a questionnaire to assess whether they had performed a list of activities in the seven days prior to survey completion. Results were analysed using frequency tabulations, contingency table analyses and chi square tests.</p> <p>Results</p> <p>A total of 766 surveys were completed, 29 surveys were excluded as the women completing them were less than 20 weeks pregnant, while 161 women completed the survey more than once. Ninety seven per cent of women completed the survey when approached for the first time, while 87% completed the survey when approached a subsequent time. In the week prior to completing the survey 82.6% of women had consumed a caffeinated beverage, 42.1% had had sexual intercourse, 32.7% had lifted something over 12 kilograms, 21.4% had consumed alcohol and 6.4% had performed vigorous exercise. The weekly prevalence of heavy lifting was higher for multiparous women compared to nulliparous women.</p> <p>Conclusions</p> <p>The results of this study can be used to inform future research into activities as acute triggers of pregnancy complications.</p

Record linkage to obtain birth outcomes for the evaluation of screening biomarkers in pregnancy: a feasibility study

<p>Abstract</p> <p>Background</p> <p>Linking population health data to pathology data is a new approach for the evaluation of predictive tests that is potentially more efficient, feasible and efficacious than current methods. Studies evaluating the use of first trimester maternal serum levels as predictors of complications in pregnancy have mostly relied on resource intensive methods such as prospective data collection or retrospective chart review. The aim of this pilot study is to demonstrate that record-linkage between a pathology database and routinely collected population health data sets provides follow-up on patient outcomes that is as effective as more traditional and resource-intensive methods. As a specific example, we evaluate maternal serum levels of PAPP-A and free <it>β</it>-hCG as predictors of adverse pregnancy outcomes, and compare our results with those of prospective studies.</p> <p>Methods</p> <p>Maternal serum levels of PAPP-A and free <it>β</it>-hCG for 1882 women randomly selected from a pathology database in New South Wales (NSW) were linked to routinely collected birth and hospital databases. Crude relative risks were calculated to investigate the association between low levels (multiples of the median ≤ 5^thpercentile) of PAPP-A or free <it>β</it>-hCG and the outcomes of preterm delivery (<37 weeks), small for gestational age (<10^thpercentile), fetal loss and stillbirth.</p> <p>Results</p> <p>Using only full name, sex and date of birth for record linkage, pregnancy outcomes were available for 1681 (89.3%) of women included in the study. Low levels of PAPP-A had a stronger association with adverse pregnancy outcomes than a low level of free <it>β</it>-hCG which is consistent with results in published studies. The relative risk of having a preterm birth with a low maternal serum PAPP-A level was 3.44 (95% CI 1.96–6.10) and a low free <it>β</it>-hCG level was 1.31 (95% CI 0.55–6.16).</p> <p>Conclusion</p> <p>This study provides data to support the use of record linkage for outcome ascertainment in studies evaluating predictive tests. Linkage proportions are likely to increase if more personal identifiers are available. This method of follow-up is a cost-efficient technique and can now be applied to a larger cohort of women.</p

Statistical Analyses of "Randomly Sourced Data"

Warner in 1965 introduced randomized response, and since then many extensions and improvements to the Warner model have been done. In this study a randomized response model applicable to continuous data that considers a mixture of two normal distributions is considered and analyzed. This includes a study of the efficiency, an estimation of some unknown parameters and a discussion of contaminated data issues and an application of this method to the problem of estimating Oakland University student income is presented and discussed. Also, this study includes inference for two or more populations of the same structure as the randomized response model introduced. The impact of this randomized response model on ranking and selection method is quantified for an indifference-zone procedure and a subset selection procedure. A study on how to choose the best population between k distinct populations using an indifference-zone procedure is presented and some tables for the required sample size needed to have a probability of correct selection higher than some specified value in the preference zone for the randomized response model considered are provided. An application of the subset selection procedure on the considered randomized response model is discussed. The subset selection study is provided for 2 configurations, the slippage configuration and the equi-spaced configuration, and tables are provided for both configurations. Finally, a discussion on the use of the data obtained from the Bayesian Improved Surname and Geocoding analysis (BISG) tool in hypothesis testing for disparity between different populations. Two approaches are provided on how to use the information arising from the BISG