Machine learning forecasting of solar PV production using single and hybrid models over different time horizons.

This study uses operational data from a 180 kWp grid-connected solar PV system to train and compare the performance of single and hybrid machine learning models in predicting solar PV production a day-ahead, a week-ahead, two weeks ahead and one month-ahead. The study also analyses the trend in solar PV production and the effect of temperature on solar PV production. The performance of the models is evaluated using R2 score, mean absolute error and root mean square error. The findings revealed the best-performing model for the day ahead forecast to be Artificial Neural Network. Random Forest gave the best performance for the two-week and a month-ahead forecast, while a hybrid model composed of XGBoost and Random Forest gave the best performance for the week-ahead prediction. The study also observed a downward trend in solar PV production, with an average monthly decline of 244.37 kWh. Further, it was observed that an increase in the module temperature and ambient temperature beyond 47 °C and 25 °C resulted in a decline in solar PV production. The study shows that machine learning models perform differently under different time horizons. Therefore, selecting suitable machine learning models for solar PV forecasts for varying time horizons is extremely necessary.

Clinical algorithms for management of fetal heart rate abnormalities during labour.

OBJECTIVE: To construct algorithms with a sequential decision analysis pathway for monitoring of the fetal heart rate and managing fetal heart rate bradycardia, late decelerations and tachycardia during labour. POPULATION: Low-risk pregnant women in labour with singleton cephalic term pregnancies. SETTING: Institutional births in low- and middle-income countries. SEARCH STRATEGY: We sought relevant published clinical algorithms, guidelines and randomised trials/reviews by searching the Cochrane Library, PubMed and Google on the terms: "fetal AND heart AND rate AND algorithm AND (labour OR intrapartum)", up to March 2020. CASE SCENARIOS: The two scenarios included were fetal heart rate bradycardia or late decelerations (potentially related to uterine rupture, placental abruption, cord prolapse, maternal hypotension, uterine hyperstimulation or unexplained) and fetal heart rate tachycardia (potentially related to maternal hyperthermia, infection, dehydration or unexplained). The algorithms provide pathways for definition, assessment, diagnosis, interventions to correct the abnormalities and ongoing monitoring leading to mode of birth, and linking to other algorithms in the series. CONCLUSIONS: The algorithms provide a framework for monitoring and managing fetal heart rate bradycardia, late decelerations and tachycardia during labour. We emphasise the inherent diagnostic inaccuracy of fetal heart rate monitoring, the tendency to over-diagnose fetal compromise, the need to consider fetal heart rate information in the context of other clinical features and the need to engage in informed, shared, family-centred decision-making. We note the need for further research on methods of fetal assessment during labour including clinical fetal arousal testing and the rapid biophysical profile test. TWEETABLE ABSTRACT: Decision analysis algorithms for fetal bradycardia, late decelerations and tachycardia highlight diagnostic limitations.

Declining maternal mortality in the face of persistently high HIV prevalence in a middle-income country.

OBJECTIVE: To estimate maternal mortality ratio (MMR) and determine maternal death causes and trends in Greater Soweto, Johannesburg, South Africa. DESIGN: Cross-sectional study. SETTING: Chris Hani Baragwanath Maternity Hospital (CHBMH) in Greater Soweto. POPULATION: Maternal deaths at CHBMH. METHODS: Record review of maternal deaths from 1997 to 2012, using hospital death records, with denominator data from the district health information system and the hospital. MAIN OUTCOME MEASURES: Maternal mortality ratio per 100,000 live births, and causes of death classified as in the South African confidential enquiries. RESULTS: There were 479 deaths, with a peak MMR of 139 in 2004 and a decline to 86 in 2012. Of 332 women tested, 245 (74%) were HIV-infected. Nonpregnancy-related infection (40%) was the most frequent cause of death, followed by hypertension (16%) and obstetric haemorrhage (13%). HIV infection rates in these groups were 92%, 30% and 61%, respectively. Previous caesarean section was associated with obstetric haemorrhage death (odds ratio [OR] 3.2, 95% confidence interval [95% CI] 1.7-6.0), maternal age ≥35 years with hypertension death (OR 2.2, 95% CI 1.2-3.7) and antenatal anaemia with nonpregnancy-related infection death (OR 4.0, 95% CI 2.3-6.9), compared with other causes of death. CONCLUSION: There is evidence of a decline in MMR since HIV treatment for pregnant women was introduced in 2004. Previous caesarean section, advanced maternal age, and anaemia were associated with death from obstetric haemorrhage, hypertensive disorders of pregnancy and nonpregnancy-related infections, respectively. MMR may be further reduced with accelerated initiation of HIV treatment during pregnancy.

Does human immunodeficiency virus infection protect against preeclampsia-eclampsia?

OBJECTIVE: In view of recent suggestions that human immunodeficiency virus (HIV) infection may protect against preeclampsia, this study was done to evaluate whether untreated HIV-positive pregnant women have a lower rate of preeclampsia-eclampsia than HIV-negative women. METHODS: Subjects for this study were pregnant women from Soweto, South Africa, who gave birth from March to December 2002 at midwife-run clinics or at the Chris Hani Baragwanath Hospital and in whom the HIV status was known. A sample size calculation indicated that 2,588 subjects would be required to show statistical significance at P <.05 with a power of 80% for a reduction in the rate of preeclampsia from 8% to 5% with HIV seropositivity, assuming an HIV seroprevalence rate of 30%. Data collection was by record review from randomly selected patient files and birth registers. RESULTS: In the total sample of 2,600 women, 1,797 gave birth at the hospital and 803 at the midwife-run clinics. The HIV seroprevalence rate was 27.1%. Hypertension was found in 17.3% of women, with 5.3% having preeclampsia-eclampsia. The rates of preeclampsia-eclampsia were 5.2% in HIV-negative and 5.7% in HIV-positive women (P =.61). CD4 count results were available for only 13 women (0.5%). CONCLUSION: Human immunodeficiency virus seropositivity was not associated with any reduction in the risk of developing preeclampsia-eclampsia.

Longitudinal effects of integrated treatment on alcohol use for persons with serious mental illness and substance use disorders.

A randomized experimental design was used to assign participants to an integrated mental health and substance use treatment program or to standard hospital treatment. A multilevel, nonlinear model was used to estimate hospital treatment effects on days of alcohol use for persons with serious mental illness and substance use disorders over 18 months. The integrated treatment program had a significant effect on the rate of alcohol use at 2 months postdischarge, reducing the rate of use by 54%. Motivation for sobriety at hospital discharge, posttreatment self-help attendance, and social support for sobriety were also found to reduce the rate of use during the follow-up period. Implications for mental health treatment and aftercare support are discussed.

Prune-belly syndrome with prostatic hypoplasia, bladder wall rupture, and massive ascites in a fetus with trisomy 18.

An association has been noted between trisomy 18 and genitourinary abnormalities, with six previous reports of the prune-belly syndrome occurring in patients with trisomy 18. We have observed a 120-g fetus of 18 weeks' gestational age at autopsy in whom there was severe prune-belly syndrome and trisomy 18. Serial histologic sections and reconstruction of the lower urinary tract demonstrated severe prostatic hypoplasia with a dilated, angulated prostatic urethra. Obstruction appeared to be present at the internal sphincter as a result of loss of prostatic support of the bladder. The bladder was distended and hypertrophic, and had a disruption of its wall near the apex. Massive ascites and intraabdominal urine accumulation had produced abdominal distention and pulmonary hypoplasia. The findings in this case lend support to the concept of prostatic hypoplasia as a cause of prune-belly syndrome and to the unexplained association between trisomy 18 and genitourinary anomalies including the prune-belly syndrome.

The surgical clerkship experience: self, departmental, and institutional assessment.

The purpose of this study was to investigate to what extent students' assessments of their clerkship experiences varied in relation to perceptions of self-improvement, the time of year in which the clerkship experience took place, and the origin of the assessment device (departmental versus institutional). All students enrolled in each of six surgery clerkship rotations over the course of 1 academic year (224 students) were administered two questionnaires on completion of the clerkship. One questionnaire was institutionally developed and supported, whereas the other was departmentally sponsored. Results of multiple regression analyses indicated that (1) when students felt their medical skills had improved as a result of clerkship participation, the clerkship was considered of high quality; (2) students' perceived improvement in communication skills decreased as the academic year progressed; and (3) students did not alter their responses to the questionnaires based on whether the instrument was institutionally or departmentally sponsored.

Sclerotium formation in an Aspergillus flavus wound infection.

A patient studied at autopsy was found to have a post-operative wound infection with Aspergillus flavus in which there was the formation of fungal structures resembling sclerotia. The ability of Aspergillus to form sclerotia in tissue appears to be rare and is related to the strain of Aspergillus flavus. Since sclerotia are considered as structures capable of withstanding dramatic shifts in the environment, the production of these in tissue may affect the efficacy of antifungal therapy.

Psychologic treatment for the type A behavior pattern and for coronary heart disease: a meta-analysis of the literature.

The Type A behavior pattern (TABP) is a recognized risk factor for coronary heart disease (CHD), and yet treatments aimed at its modification are not in widespread use. We reviewed the literature of controlled studies (N = 18) of the psychologic treatment of the TABP and of CHD with the statistical method of "meta-analysis." The results of each study were converted to a standardized "Effect Size" (ES). The mean ES for TABP measures was 0.61 +/- 0.20 (95% confidence interval) (p less than 0.001), indicating that after treatment subjects across all studies reduced their TABP scores by half a standard deviation. The combined significance probability (pc) across studies for reduction in 3-year combined mortality and myocardial infarction was pc less than 0.0001, corresponding to a reduction in coronary events of roughly 50% after psychologic treatment. This finding must be approached with caution because it is based on only two studies. The analysis suggested that a combination of treatment techniques is most effective in reducing TABP and CHD recurrences. The literature was critiqued, and limitations of the findings are discussed. We conclude that psychologic intervention to reduce TABP may improve clinical outcome of CHD and that this deserves further study and preliminary clinical application.

Type A behavior and blood pressure during general surgery.

The Type A behavior pattern (TABP) has been demonstrated as a risk factor for the development of coronary heart disease (CHD). Psychophysiologic studies suggest that the TABP may be associated with autonomic hyperreactivity to a variety of stressors. Recent studies report an association of TABP with autonomic hyperreactivity in patients under general anesthesia for coronary artery bypass surgery. The present study did not find a significant correlation between the TABP and intraoperative rise in blood pressure for 44 noncardiac patients undergoing anesthesia for elective general surgical procedures. Suggestive associations were found in sub-samples with family history of CHD or age greater than 60 years. Thus, the TABP may be correlated with heightened physiologic response under anesthesia only in selected populations.

Psychological and behavioral responses after coronary artery bypass surgery.

One hundred consecutive patients who underwent coronary artery bypass surgery at the Columbia-Presbyterian Medical Center from December 1972 through February 1975 were evaluated at surgery and then followed for as long as 4 1/2 years to study their postoperative psychosocial and behavioral course. One patient died during the first 30 days. At 4 1/2 years, 23 patients were reported as deceased, 15 from cardiac causes. The majority of the long-term survivors had substantially less angina and greater exercise capacity; surgery did not increase the number of patients who were employed, but led to substantial improvements in the quality of life, including general pleasure, reduction of anxiety and depression and subjective improvement in job and family roles. Sexual adjustment improved the least; the frequency of sexual relations tended to decrease. Compliance with the medical regimen was relatively good for smoking and exercise, but not for diet or type A behavior, suggesting a need for psychological intervention.

Type A behavior and the thallium stress test.

Several recent studies have examined the association between Type A personality and coronary artery disease (CAD) by coronary angiography. Most of these studies have reported a significant association. The present study is an attempt at further confirmation, using a new non-invasive technique for measuring CAD. Subjects were 53 patients undergoing routine exercise stress tests with concomitant thallium-201 myocardial perfusion studies. Five aspects of Type A behavior were assessed by the use of the Rosenman-Friedman Semistructured Interview, and each was rated on a three-point scale. Severity of CAD was independently estimated on a four-point scale. Pearson correlation coefficients were separately computed for patients with and without reported history of myocardial infarction (MI). For 37 patients without reported MI, CAD severity was significantly correlated with Overall Type A (r = -0.53), Vocal Characteristics (r = -0.53), Job Involvement (r = -0.36) and Aggressiveness (r = -0.48), but not Time Urgency (r = -0.25). For 16 patients with reported MI, CAD severity was significantly correlated with Job Involvement only (r = +0.49). The data are consistent with the association of Type A personality and coronary atherogenesis, but may also reflect Type A psychological and physiological characteristics. Future studies may be able to examine these and other aspects of Type A behavior using this noninvasive technique in more diverse patient populations.

Type A behavior and blood pressure during coronary artery bypass surgery.

Systemic hypertension has been reported as common during coronary artery bypass surgery. The coronary-prone Type A behavior pattern has been associated with heightened reactivity of the sympathetic nervous system. Therefore, the possible relationships between the two was explored. Significant correlations were found between systolic blood pressure rise during surgery and interview ratings of overall Type A (p < 0.05), aggressive content (p < 0.01), and job commitment (p < 0.001). A statistically association was also found between diastolic pressure rise and the job commitment rating (p < 0.01). Significant correlations were still present after controlling for the role of physical predictors of blood pressure rise by statistical multiple regression analysis. The data suggest that patients with Type A behavior characteristics manifest an autonomic hyperactivity which is present under general anesthesia. This hyperactivity may contribute to the association of Type A behavior pattern and coronary heart disease.

Psychological intervention in coronary heart disease: a review.

Psychological intervention studies designed to reduce cardiac morbidity are reviewed. Preliminary findings suggest that various psychotherapeutic modalities may be effective. Such studies also provide an avenue through which the physical and psychological mechanisms involved in coronary heart disease and their interactions may be clarified. Implications for clinical interventions are also discussed.

Type A behavior pattern and coronary angiographic findings.

One hundred forty-seven consecutive patients scheduled to undergo coronary angiography were classified according to the type-A behavior pattern. Statistically significant correlations were found between diseases severity and the physical risk factors cholesterol, smoking, hypertension, sex, and age. The correlation of the behavior pattern with angiographic disease severity was of the same magnitude as that of the other risk factors except cholesterol, which was greater. The association between the behavior pattern and severity persisted after adjustments had been made for the effects of five other major risk factors.

Delirium after coronary artery bypass surgery.

The incidence of postoperative delirium following coronary artery bypass surgery was 28%. This rate is comparable to that after open-heart surgery. However, of those variables which were previously found to correlate with delirium in the open-heart group, only severity of postoperative illness in the recovery room significantly correlated with delirium in patients having bypass. The relationship between personality type and delirium, previously found to be signficant, was suggestively associated in these patients. A history of myocardial infarction prior to surgery was significantly associated with delirium.