bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retrograde-rotating Exoplanets Experience Obliquity Excitations in an Eccentricity-enabled Resonance
Authors: Kreyche Steven M. , Barnes Jason W. , Quarles Billy L. , Lissauer Jack J. , Chambers John E. , Hedman Matthew M. 
Published: April 2020

Abstract
Previous studies have shown that planets that rotate retrograde (backward with respect to their orbital motion) generally experience less severe obliquity variations than those that rotate prograde (the same direction as their orbital motion). Here, we examine retrograde-rotating planets on eccentric orbits and find a previously unknown secular spin–orbit resonance that can drive significant obliquity variations. This resonance occurs when the frequency of the planet’s rotation axis precession becomes commensurate with an orbital eigenfrequency of the planetary system. The planet’s eccentricity enables a participating orbital frequency through an interaction in which the apsidal precession of the planet’s orbit causes a cyclic nutation of the planet’s orbital angular momentum vector. The resulting orbital frequency follows the relationship

, where

and

are the rates of the planet’s changing longitude of periapsis and longitude of ascending node, respectively. We test this mechanism by simulating cases of a simple Earth–Jupiter system and confirm the predicted resonance. Over the course of 100 Myr, the test Earths with rotation axis precession rates near the predicted resonant frequency experienced pronounced obliquity variations of the order of 10°–30°. These variations can be significant and suggest that while retrograde rotation is a stabilizing influence most of the time, retrograde rotators can experience large obliquity variations if they are on eccentric orbits and enter this spin–orbit resonance.
Vernal pool amphibian breeding ecology monitoring from 1931 to present: A harmonised historical and ongoing observational ecology dataset
Authors: Garretson Alexis , Napoli Megan , Feldsine Natalie , Adler-Colvin Penelope , Long Elizabeth 
Published: April 2020

For 88 years (1931-present), the Mohonk Preserve's Daniel Smiley Research Center has been collecting data on occupancy and reproductive success of amphibian species, as well as associated water quality of 11 vernal pools each spring (February to May). Though sampling effort has varied over the dataset range, the size of the dataset is unprecedented within the field of amphibian ecology. With more than 2,480 individual species sampling dates and more than 151,701 recorded individual occurrences of the nine amphibian species, the described dataset represents the longest and largest time-series of herpetological sampling with paired water quality data.
We describe the novel publication of a paired dataset of amphibian occurrence with environmental indicators spanning nearly 90 years of data collection. As of February 2020, the dataset includes 2,480 sampling dates across eleven vernal pools and 151,701 unique occurrences of egg masses or individuals recorded across nine species of amphibian. The dataset also includes environmental conditions associated with the species occurrences with complete coverage for air temperature and precipitation records and partial coverage for a variety of other weather and water quality measures. Data collection has included species, egg mass and tadpole counts; weather conditions including precipitation, sky and wind codes; water quality measurements including water temperature and pH; and vernal pool assessment including depth and surface vegetation coverage. Collection of data was sporadic from 1931–1991, but data have been collected consistently from 1991 to present. We also began monitoring dissolved oxygen, nitrate concentrations and conductivity of the vernal pools using a YSI Sonde Professional Plus Instrument and turbidity using a turbidity tube in February 2018. The dataset (and periodic updates), as well as metadata in the EML format, are available in the Environmental Data Initiative Repository under package edi.398.
Burning issues in blood pressure control
Authors: Ker J. A. , Outhoff K. 
Published: April 2020

Globally more than 1 billion people have hypertension and it is predicted that because of ageing populations and increasing sedentary lifestyles, this figure will rise to about 1.5 billion by 2025. Elevated blood pressure (BP) is the leading cause of premature death and morbidity due to stroke and ischemic heart disease. Hypertension is also a major risk factor for heart failure, atrial fibrillation, chronic kidney disease, peripheral arterial disease and cognitive decline. This article discusses the current evidencebased treatment guidelines and pressing temporal issues in optimal blood pressure control.
Brand innovator versus multisource cefpodoxime in respiratory tract infections: A comparative study
Authors: Snyman J. R. , Medlen C. E. 
Published: April 2020

Purpose: In everyday practice clinicians are overwhelmed by claims from the pharmaceutical industry and, due to marketing efforts, they often view generic multisource products with scepticism despite proof and registration by regulatory authorities of bioequivalence. The primary aim of this study was exploratory and aimed to compare the acceptability of generic cefpodoxime (Cepodem®) versus the innovator brand product (Orelox®) in terms of effectiveness, safety and tolerability in a general private practice setting in South Africa in the treatment of upper and lower respiratory tract infections.Methods and patients: Ninety patients were recruited and randomised to receive either product for 10 days after clinical diagnoses of either tonsillo-pharyngitis or rhino-sinusitis or pneumonia.Results: It was demonstrated that both products resulted in similar clinical and bacteriological cure rates with also no difference in tolerability profiles.Conclusion: These findings support the bioequivalence data as submitted for regulatory approval, of the generic Cepodem® translating into clinical effectiveness and argues against the need for a clinical non-inferiority study to demonstrate sameness.
Optimising the learning environment for undergraduate students in the Department of Family Medicine at Sefako Makgatho Health Sciences University
Authors: Govender I. , De Villiers M. 
Published: April 2020

Background: An important determinant of a medical student’s behaviour and performance is the department’s teaching and learning environment. Evaluation of such an environment can explore methods to improve educational curricula and optimise the academic learning environment.Aim: The aim is to evaluate the educational environment of undergraduate students in the Department of Family Medicine as perceived by students.Setting: This descriptive quantitative study was conducted with one group of final-year students (n = 41) enrolled in 2018, with a response rate of 93% (n = 39). Students were in different training sites at SMU.Methods: Data were collected using the Dundee Ready Educational Environmental Measure (DREEM) questionnaire. Total and mean scores for all questions were calculated.Results: The learning environment was given a mean score of 142/200 by the students. Individual subscales show that ‘academic self-perception’ was rated the highest (25/32), while ‘social self-perception’ had the lowest score (13/24). Positive perception aspects of the academic climate included: student competence and confidence; student participation in class; constructive criticism provided; empathy in medical profession; and friendships created. Areas for improvement included: provision of good support systems for students; social life improvement; course coordinators being less authoritarian and more approachable; student-centred curriculum with less emphasis on factual learning and factual recall.Conclusion: Students’ perceptions of their learning environment were more positive than negative. The areas of improvement will be used to draw lessons to optimise the curriculum and learning environment, improve administrative processes and develop student support mechanisms in order to improve students’ academic experience.
Caregivers of children with diabetes mellitus: challenges of caring for and perceptions of consultations in a South African public sector context
Authors: Dhada B. L. , Blackbeard D. R. 
Published: April 2020

Background: Understanding caregivers’ challenges in caring for children with diabetes mellitus (DM) and their perceptions of consultations with the multidisciplinary team (MDT) may be valuable in assisting in achieving control.Methods: Using a qualitative descriptive design, anonymised, transcribed recorded data from semi-structured interviews with a purposive sample of caregivers were thematically analysed in three areas: (a) challenges experienced in caring for their child, (b) feelings around MDT consultations pertaining to helpfulness, support and diabetes education, and (c) suggestions for clinic improvement. University of KwaZulu-Natal ethics committee approval and informed consent were obtained.Results: All caregivers (n = 14) were female with a mean age of 38 years. Total diabetes caring experience was 47.4 years. The primary caregiver was the mother in nine interviews. Ten interviewees were unemployed. The children’s ages ranged from 3 to 15 years with mean age at diagnosis of 6.7 years. Caregivers’ challenges in caring were reflected in two global themes: ‘DM care is difficult’ and needs a ‘process of adjustment’ over time to accept and meet demands. These included emotional, practical, financial, behavioural and social challenges. Caregivers’ feelings regarding overall consultations were mostly positive, including satisfaction. The MDT’s helpfulness and support were perceived as patient-centred and meeting education and care needs. Negative feelings were frustration and boredom. Clinic improvement suggestions included shorter waiting times and seeing the same doctor for continuity of care.Conclusion: Caregivers in South Africa experienced caring for children with DM as difficult, requiring an adjustment process. Perceptions of consultations were mostly positive. Relevant clinic improvements were suggested.
An HIV-free generation: review of prevention strategies
Authors: Moodley I. 
Published: April 2020

Globally South Africa has the largest HIV epidemic, with an estimated 7.7 million people living with HIV (PLHIV). The burden of HIV in South Africa varies by age, gender and key population groups. Prevalence is highest among adults between the ages of 15 and 49 years and is higher among females than males. The prevalence rate also varies by province with the highest rates observed in KwaZulu-Natal, Free State, Eastern Cape, Mpumalanga and Northwest.While greater access to anti-retroviral treatment (ART) has significantly reduced the number of deaths and new infections, the number of new infections is still relatively high, highlighting the need for prevention.Initial prevention strategies focus on behavioural change through increased education and awareness to ensure safer sex, mainly through peer education, condom distribution and voluntary medical male circumcision (VMMC), all of which are in place with varying degrees of success. More recently newer approaches are being considered such as pre-exposure prophylaxis (PrEP) and treatment as prevention (TasP). The major challenge is still behavioural change.This review sets out to critically evaluate the current and newer approaches. Studies suggest that to achieve greater impact, rather than targeting the general population, prevention strategies should focus on vulnerable populations and in provinces with the highest HIV burden.
A profile of Caesarean sections performed at a district hospital in Tshwane, South Africa
Authors: Govender I. , Steyn C. , Maphasha O. , Abdulrazak A. T. 
Published: April 2020

Introduction: Caesarean section (CS) is a common obstetric procedure that prevents neonatal and maternal death when performed correctly if indicated; however, CS can give rise to complications that lead to maternal and perinatal morbidity and mortality. Rates of CS are increasing worldwide, although the World Health Organization (WHO) has indicated an ideal rate of 5–15%. South African CS rates are higher than the ideal.Methods: Maternity records of 2015 were reviewed at Odi District Hospital (ODH) to assess whether ODH complies with the ideal CS rate. In this study, extracted data include date and time of CS, maternal age, parity, gestational age, total number of previous CSs, elective or emergency, indications, anaesthesia used and registration of the surgeon.Results: There were 3 336 deliveries and 1 064 CSs (32%). The majority of women were aged from 19 to 34 years (59%), 72.8% were multiparous and 54% between 37–39 weeks’ gestation. The most common (40.1%) overall and emergency indication was foetal distress. Most CSs were emergencies (61.70%). Most elective CSs were because of a previous CS and spinal anaesthesia was used in 91.73%. Medical officers performed most of the CSs (79.0%) during working hours. The CS rate of 32% was significantly higher than the ideal 5–15% and higher than in other sub-Saharan countries with similar maternal characteristics. Indications for emergency and elective CSs were similar to previous research.Conclusion: The Caesarean section rate at ODH is higher than the recommended rate. Potential CSs therefore need to be evaluated more intensely to assess the true need for surgical intervention.
The Trace Form Over Cyclic Number Fields
Authors: Bolaños Wilmar , Mantilla-Soler Guillermo 
Published: April 2020

AbstractIn the mid 80’s Conner and Perlis showed that for cyclic number fields of prime degree p the isometry class of integral trace is completely determined by the discriminant. Here we generalize their result to tame cyclic number fields of arbitrary degree. Furthermore, for such fields, we give an explicit description of a Gram matrix of the integral trace in terms of the discriminant of the field.
Steiner symmetry in the minimization of the first eigenvalue of a fractional eigenvalue problem with indefinite weight
Authors: Anedda Claudia , Cuccu Fabrizio , Frassu Silvia 
Published: April 2020

AbstractLet
$\Omega \subset \mathbb {R}^N$
,

$N\geq 2$
, be an open bounded connected set. We consider the fractional weighted eigenvalue problem

$(-\Delta )^s u =\lambda \rho u$
in

$\Omega $
with homogeneous Dirichlet boundary condition, where

$(-\Delta )^s$
,

$s\in (0,1)$
, is the fractional Laplacian operator,

$\lambda \in \mathbb {R}$
and

$ \rho \in L^\infty (\Omega )$
.We study weak* continuity, convexity and Gâteaux differentiability of the map

$\rho \mapsto 1/\lambda _1(\rho )$
, where

$\lambda _1(\rho )$
is the first positive eigenvalue. Moreover, denoting by

$\mathcal {G}(\rho _0)$
the class of rearrangements of

$\rho _0$
, we prove the existence of a minimizer of

$\lambda _1(\rho )$
when

$\rho $
varies on

$\mathcal {G}(\rho _0)$
. Finally, we show that, if

$\Omega $
is Steiner symmetric, then every minimizer shares the same symmetry.
Association of RETN − 420 C/G Genotypes with CRP, Brain Edema, GCS, and GOS Among Patients with Traumatic Cerebral Hemorrhagic Contusion
Authors: Ibrahim Samah Abdelrahman Hassan , Arbab Mohamed Abdel Rahman , Musa Hassan Hussein 
Published: April 2020

Background: Traumatic cerebral hemorrhage is a common type of traumatic brain injury. This medical condition exists in two phases: primary, which occurs at the time of trauma, and secondary, which occurs later as a result of multiple biochemical, metabolic, and inflammatory changes that develop over time. The secondary injury is mainly irreversible and worsens the primary injury. Single nucleotide polymorphism (SNP) in RETN gene − 420 C/G is involved in the secondary injury by enhancing the inflammatory process. This study aims to find out the association of − 420 C/G RETN genotypes with C-reactive protein (CRP), brain edema, Glasgow Coma Scale (GCS), and Glasgow Outcome Score (GOS) among traumatic cerebral hemorrhagic contusions. Methods: Ninety patients with traumatic cerebral hemorrhagic contusion were enrolled in this study. Patients with hemorrhagic contusion associated with other types of brain bleeding and those with chronic diseases were excluded. GCS score was assessed upon admission and GOS was assessed upon discharge. CRP level was measured in serum by a Nyco-Card Reader II system. RETN genotypes were defined by using PCR-RFLP. Results: Ninety patients were included, 93.3% were males, and 78.9% of the patients were below 44 years old. The most common mechanism of trauma was RTA constituting 68.9%. The RETN genotypes were 25.6%, 41.1%, and 33.3% for CC, GG, and CG, respectively. G mutant allele was significantly associated with brain edema (P = 0.019) but not significantly associated with CRP, GCS, and GOS. Conclusions: SNP in RETN − 420 C/G gene was significantly associated with brain edema (P = 0.019).
Prevalence of Latent Tuberculosis in the Multiple Sclerosis Clinic and Effect of Multiple Sclerosis Treatment on Tuberculosis Testing
Authors: Bouley Andrew J. , Baber Ursela , Egnor Emily , Samaan Soleil , Sloane Jacob A. 
Published: April 2020

Abstract

Background:
Patients with a compromised immune system are at risk for converting from latent tuberculosis infection (LTBI) to active tuberculosis (TB) infection. Multiple sclerosis (MS) therapies may put individuals with LTBI at higher risk of TB.

Methods:
Patients at the Beth Israel Deaconess Medical Center MS Clinic were screened for TB as part of routine testing with the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay (Cellestis Ltd) from 2013 to 2017. Patients were tested either before or during immunomodulatory therapy.

Results:
Four of 222 patients (1.8%; 95% CI, 0.1%–3.6%) had positive QFT-GIT results; three patients had risk factors for TB, having emigrated from TB-endemic countries or worked in the health care industry. Twenty-eight of 222 patients (12.6%) had an indeterminate assay result, and 75.0% of these occurred in patients taking dimethyl fumarate. Fingolimod, natalizumab, or anti-CD20 treatments showed 0% to 7.7% indeterminate results.

Conclusions:
The prevalence of LTBI was 1.8% in the Beth Israel Deaconess Medical Center MS Clinic. Not all LTBI cases were associated with known risk factors for TB. Screening for LTBI before starting immunosuppressive agents for MS could help prevent activation of TB. Dimethyl fumarate use is associated with indeterminate QFT-GIT results, possibly due to functional effects on lymphocytes and levels of cytokines, such as interferon gamma. In contrast, fingolimod use was rarely associated with indeterminate QFT-GIT results despite a high rate of lymphopenia in virtually all patients.
Magnetic Resonance Imaging of Spinal Cord Lesions in Patients with Multiple Sclerosis in Saskatchewan, Canada
Authors: Saini Aman , Bach Kevin , Poliakov Ilia , Knox Katherine B. , Levin Michael C. 
Published: April 2020

Abstract

Background:
Spinal cord lesions (SCLs) contribute to disability in multiple sclerosis (MS). Data in Saskatchewan, Canada, concerning SCLs and their association with disability levels in patients with MS are lacking. The study objectives were to identify clinicodemographic profiles of patients with MS with respect to spinal cord magnetic resonance imaging (MRI) involvement; determine the frequency of individuals with MRI SCLs; and explore differences between patients with MS with and without SCLs with respect to disability and disease-modifying therapy status.

Methods:
A monocentric, cross-sectional, retrospective review of prospectively collected data from 532 research-consented patients seen at Saskatoon MS Clinic was performed. Data were collected from a database and electronic medical records.

Results:
Of the 356 patients (66.9%) with an SCL, 180 (50.6%) had only cervical cord lesions. Median Expanded Disability Status Scale (EDSS), ambulation, and pyramidal scores of patients with SCLs were higher than those of patients without SCLs. Of patients with EDSS scores of at least 6, those with SCLs were younger than those without SCLs (P = .01). Patients with SCLs were 55% less likely to have been on continuous disease-modifying therapy since diagnosis than patients without SCLs (adjusted odds ratio, 0.45; 95% CI, 0.25–0.81; P = .008).

Conclusions:
Prevalence and association with disability of SCLs in patients with MS are comparable with existing literature. Patients with MS with SCLs have higher levels of disability and attain EDSS scores of at least 6 at a younger age.
Nomograms for predicting overall survival and cancer-specific survival in young patients with pancreatic cancer in the US based on the SEER database
Authors: Shi Min , Zhou Biao , Yang Shu-Ping 
Published: April 2020

Background
The incidence of young patients with pancreatic cancer (PC) is on the rise, and there is a lack of models that could effectively predict their prognosis. The purpose of this study was to construct nomograms for predicting the overall survival (OS) and cancer-specific survival (CSS) of young patients with PC.

Methods
PC patients younger than 50 years old from 2004 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database were selected and randomly divided into training set and validation set. Univariable and forward stepwise multivariable Cox analysis was used to determine the independent factors affecting OS. The Fine and Gray competing risk regression model was used to determine the independent factors affecting CSS. We used significant variables in the training set to construct nomograms predicting prognosis. The discrimination and calibration power of models were evaluated by concordance index (C-index), calibration curve and 10-flod cross-validation.

Results
A total of 4,146 patients were selected. Multivariable Cox analysis showed that gender, race, grade, pathological types, AJCC stage and surgery were independent factors affecting OS. The C-index of the nomogram predicting OS in training and validation was 0.733 (average = 0.731, 95% CI [0.724–0.738]) and 0.742 (95% CI [0.725–0.759]), respectively. Competing risk analysis showed that primary site, pathological types, AJCC stage and surgery were independent factors affecting CSS. The C-index of the nomogram predicting CSS in training and validation set was 0.792 (average = 0.765, 95% CI [0.742–0.788]) and 0.776 (95% CI [0.773–0.779]), respectively. C-index based on nomogram was better in training and validation set than that based on AJCC stage. Calibration curves showed that these nomograms could accurately predict the 1-, 3- and 5-year OS and CSS both in training set and validation set.

Conclusions
The nomograms could effectively predict OS and CSS in young patients with PC, which help clinicians more accurately and quantitatively judge the prognosis of individual patients.