bluuebunny/crossref_metadata_2025_split huggingface dataset:
Power analysis of longitudinal studies with piecewise linear growth and attrition
Authors: Moerbeek Mirjam 
Published: February 2022

AbstractIn longitudinal research, the development of some outcome variable(s) over time (or age) is studied. Such relations are not necessarily smooth, and piecewise growth models may be used to account for differential growth rates before and after a turning point in time. Such models have been well developed, but the literature on power analysis for these models is scarce. This study investigates the power needed to detect differential growth for linear–linear piecewise growth models in further detail while taking into account the possibility of attrition. Attrition is modeled using the Weibull survival function, which allows for increasing, decreasing or constant attrition across time. Furthermore, this work takes into account the realistic situation where subjects do not necessarily have the same turning point. A multilevel mixed model is used to model the relation between time and outcome, and to derive the relation between sample size and power. The required sample size to achieve a desired power is smallest when the turning points are located halfway through the study and when all subjects have the same turning point. Attrition has a diminishing effect on power, especially when the probability of attrition is largest at the beginning of the study. An example on alcohol use during middle and high school shows how to perform a power analysis. The methodology has been implemented in a Shiny app to facilitate power calculations for future studies.
Risk factors associated with depression among chronic heart failure patients in Pakistan; A Systematic Review
Authors: Dastgeer Saima , Saleem Muhammad 
Published: February 2022

Abstract

Objective: To systematically review the number of studies carried out to find the risk factors associated with depression among chronic heart failure patients in Pakistan.
Methods: A systematic and methodological search strategy was established by using key words i.e., depression, heart failure, Pakistan, risk factors on databases such as Science Direct, PubMed, Research Gate, PakMedinet, JSTER and Emerald Insight. Data screening for a period of ten years i.e., 2010 to 2020 identified 771 studies while only 59 met the inclusion criteria. Only 6 out of 59 studies were declared eligible for meticulous review.
Results: Out of total search result of 771 articles, 59 (8%) full text Pakistani articles were found. Altogether 06(10%) studies met the inclusion criteria and selected for systematic review.
Conclusion: Depression among chronic heart failure patients in Pakistan is predominately linked with lack of social support, lower socioeconomic status, sedentary life style, sleep disturbance and old age. Furthermore, severity and duration of the disease, prior history of acute myocardial infarction, repeated hospitalization and co-morbidities were also reported as disease linked depression risk factors.
Keywords: Depression, Chronic heart failure, risk factors, Pakistan
6 Minute Walk Test (6MWT) for Healthy Adult Volunteers
Authors: Hussain Syed Muarraf , Tausif Faizania , Aziz Nauman , Hussain Syed Mukarram 
Published: February 2022

Objectives: To determine the 6-minute walk test (6MWT) for healthy volunteers in our population and find out the factors affecting 6MWT. Furthermore, comparing our results with published National and International data.
Study Design: Cross-sectional study.
Place and Duration of Study: This study was carried in the physiology department of Rawalpindi Medical College, from 1st July 2019 to 31st December 2019.
Materials and Methods: A total of 129 adult healthy volunteers between 18 and 60 years of age were included in this study after the application of inclusion and exclusion criteria. A 6-minute walk test (6MWT) was carried out in a standardized procedure. The height, weight, and BMI were recorded on predesigned Performa. Distance covered in 6-minute, heart rate, systolic BP, Diastolic BP, SPO2, Borg Scale Dyspnea score, Borg Scale Fatigue score were recorded before and after the 6-minute walk test. Correlation and its significance were calculated among anthropometric and physiological variables.
Results: Seventy (54%) men and Fifty-nine (46%) women participated in the study. The mean distance covered for all subjects was 430.412±63.0150. The distance covered by the female subject was 388.720±30.104 and 439.533±68.355 by male subjects. The mean age of the subjects was 31.64 ±12.36, while the mean BMI was 22.06 ±4.15. The mean heart rate value before the test is 77.72±1.48 and after the test is 92.84±1.12. The mean systolic BP value before the walk was 122.65±11.75 and after the walk, it was 106.5±9.83. Mean diastolic BP before the walk was 80.55±12.61 and after the walk, it was 76.5±9.83. SPO2 mean value before the walk was 96.23±1.4 and after the walk is 98.2±1.17. Borg scale dyspnea score mean value before the test is 0 ± 0 and after the test it was 0.67±0.76 and Borg scale fatigue score mean value before the walk is 1.32±0.73 and after the walk is 1.62±0.92. A positive correlation was noted with height, while a negative correlation was noted with age and BMI. Gender also showed a significant relationship with the 6MWD.
Conclusion: The distance covered in 6-minute is shorter than the studies carried out in different parts of the world. Age, gender, height, and BMI showed a significant relationship with 6MWD. Those reference values for the 6MWD should not be used in our population, as it overestimates the distance and may interfere with the significance of the test.
Outcomes of patients presenting with Cholecystitis in terms of Early vs Delayed Cholecystectomy
Authors: Qaiser Maryam , Rehan Maryyam , Siddique Khurram , Anwar Muhammad Idrees , Khan Omer Habib , Rehan Kausar 
Published: February 2022

Introduction: Biliary tract diseases comprise the most frequently occurring pathology in the abdomen, among which cholelithiasis affects 10-15% of the population. Early laparoscopic cholecystectomy, performed within 72 hours 2) Interval laparoscopic cholecystectomy, performed within 72 hours to 6 weeks 3) Delayed laparoscopic cholecystectomy in which patients are treated with antibiotics and given date of surgery within 6-8 weeks according to international criteria.
Objective: To find out the variability between hot, urgent, and delayed laparoscopic cholecystectomy in terms of clinical complications and to find out the readmission rate, the persistence of symptoms, and the safety of the procedure.
Materials and Methods: This is a retrospective study carried out in the Surgical Unit ll, Holy Family Hospital, Rawalpindi from January 2018 to March 2018. All adult male and female patients presenting with acute cholecystitis and pancreatitis were included in the study.
Results: Total number of patients included in our study is 82. Most of the patients were female 80.5% with a mean age of 44 years. Most of the patients were categorized under delayed laparoscopic cholecystectomy 93.9%, 6.1% underwent interval/urgent cholecystectomy, and 1.2% early/hot cholecystectomy. Diagnosis in the study showed acute cholecystitis in 79.3% of patients, pancreatitis in 7.3%, empyema /gangrene of gallbladder in 6.1% mucocele in 6.1%, and choledocholithiasis in 1.2% of patients. Hence we figured out that performing early cholecystectomy leads to lesser complications.
Conclusion: Early laparoscopic cholecystectomy was found out to be a safe and cost-effective procedure. There is an increased incidence of readmission and complications with delayed laparoscopic cholecystectomy. We suggest that measures must be taken in Pakistan to follow international guidelines in health practices to improve patient care.
Discovery of 16 New Members of the Solar Neighborhood Using Proper Motions from CatWISE2020
Authors: Kota Tarun , Kirkpatrick J. Davy , Caselden Dan , Marocco Federico , Schneider Adam C. , Gagné Jonathan , Faherty Jacqueline K. , Meisner Aaron M. , Kuchner Marc J. , Casewell Sarah , Kacholia Kanishk , Bickle Tom , Beaulieu Paul , Colin Guillaume , Hamlet Leslie K. , Schümann Jörg , Tanner Christopher ,   The Backyard Worlds: Planet 9 Collaboration
Published: February 2022

Abstract
In an effort to identify nearby and unusual cold objects in the solar neighborhood, we searched for previously unidentified moving objects using CatWISE2020 proper motion data combined with machine learning methods. We paired the motion candidates with their counterparts in 2MASS, UHS, and VHS. Then we searched for white dwarf, brown dwarf, and subdwarf outliers on the resulting color–color diagrams. This resulted in the discovery of 16 new dwarfs, including 2 nearby M dwarfs (<30 pc), a possible young L dwarf, a high-motion early-T dwarf, and 3 later-T dwarfs. This research represents a step forward in completing the census of the Sun’s neighbors.
SN 2020sck: Deflagration in a Carbon-Oxygen White Dwarf
Authors: Dutta Anirban , Sahu D. K. , Anupama G. C. , Joharle Simran , Kumar Brajesh , J Nayana A , Singh Avinash , Kumar Harsh , Bhalerao Varun , Barway Sudhansu 
Published: February 2022

Abstract
We present optical UBVRI photometry and low-to-medium resolution spectroscopic observations of type Iax supernova SN 2020sck spanning −5.5 days to +67 days from maximum light in the B-band. From the photometric analysis we find Δm

B
(15) = 2.03 ± 0.05 mag and M

B
= −17.81 ± 0.22 mag. Radiation diffusion model fit to the quasi-bolometric light curve indicates 0.13 ± 0.02 M
⊙ of 56Ni and 0.34 M
⊙ of ejecta are synthesized in the explosion. Comparing the observed quasi-bolometric light curve with the angle-averaged bolometric light curve of a three-dimensional pure deflagration explosion of M
ch carbon-oxygen white dwarf, we find agreement with a model in which 0.16 M
⊙ of 56Ni and 0.37 M
⊙ of ejecta is formed. By comparing the +1.4 days spectrum of SN 2020sck with synthetic spectrum generated using SYN++, we find absorption features due to C ii, C iii, and O i. These are unburned materials in the explosion and indicate a C–O white dwarf. One-dimensional radiative transfer modeling of the spectra with TARDIS shows higher density in the ejecta near the photosphere and a steep decrease in the outer layers with an ejecta composition dominated mostly by C, O, Si, Fe, and Ni. The star-formation rate of the host galaxy computed from the luminosity of the Hα (λ6563) line is 0.09 M
⊙ yr−1, indicating a relatively young stellar environment.
PSP/IS⊙IS Observation of a Solar Energetic Particle Event Associated with a Streamer Blowout Coronal Mass Ejection during Encounter 6
Authors: Getachew T. , McComas D. J. , Joyce C. J. , Palmerio E. , Christian E. R. , Cohen C. M. S. , Desai M. I. , Giacalone J. , Hill M. E. , Matthaeus W. H. , McNutt R. L. , Mitchell D. G. , Mitchell J. G. , Rankin J. S. , Roelof E. C. , Schwadron N. A. , Szalay J. R. , Zank G. P. , Zhao L.-L. , Lynch B. J. , Phan T. D. , Bale S. D. , Whittlesey P. L. , Kasper J. C. 
Published: February 2022

Abstract
In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS⊙IS’s Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the open radial magnetic field. The event shows velocity dispersion, and strong particle anisotropies are observed throughout the event, showing that more particles are streaming outward from the Sun. We do not see a shock in the in situ plasma or magnetic field data throughout the event. Heavy ions, such as O and Fe, were detected in addition to protons and 4He, but without significant enhancements in 3He or energetic electrons. Our analysis shows that this event is associated with a slow streamer blowout coronal mass ejection (SBO-CME), and the signatures of this small CME event are consistent with those typical of larger CME events. The time–intensity profile of this event shows that the Parker Solar Probe encountered the western flank of the SBO-CME. The anisotropic and dispersive nature of this event in a shockless local plasma gives indications that these particles are most likely accelerated remotely near the Sun by a weak shock or compression wave ahead of the SBO-CME. This event may represent direct observations of the source of the low-energy SEP seed particle population.
Discovering Supernovae at the Epoch of Reionization with the Nancy Grace Roman Space Telescope
Authors: Moriya Takashi J. , Quimby Robert M. , Robertson Brant E. 
Published: February 2022

Abstract
Massive stars play critical roles for the reionization of the universe. Individual massive stars at the reionization epoch (z > 6) are too faint to observe and quantify their contributions to reionization. Some massive stars, however, explode as superluminous supernovae (SLSNe) or pair-instability supernovae (PISNe) that are luminous enough to observe even at z > 6 and allow for the direct characterization of massive star properties at the reionization epoch. In addition, hypothetical long-sought-after PISNe are expected to be present preferentially at high redshifts, and their discovery will have a tremendous impact on our understanding of massive star evolution and the formation of stellar mass black holes. The near-infrared Wide Field Instrument on the Nancy Grace Roman Space Telescope will excel at discovering such rare high-redshift supernovae. In this work, we investigate the best survey strategy to discover and identify SLSNe and PISNe at z > 6 with Roman. We show that the combination of the F158 and F213 filters can clearly separate both SLSNe and PISNe at z > 6 from nearby supernovae through their colors and magnitudes. The limiting magnitudes are required to be 27.0 mag and 26.5 mag in the F158 and F213 filters, respectively, to identify supernovae at z > 6. If we conduct a 10 deg2 transient survey with these limiting magnitudes for five years with a cadence of one year, we expect to discover 22.5 ± 2.8 PISNe and 3.1 ± 0.3 SLSNe at z > 6, depending on the cosmic star formation history. The same survey is estimated to discover 76.1 ± 8.2 PISNe and 9.1 ± 0.9 SLSNe at 5 < z < 6. Such a supernova survey requires the total observational time of approximately 525 hr in five years. The legacy data acquired with the survey will also be beneficial for many different science cases including the study of high-redshift galaxies.
Acute on Chronic Limb Ischemia Treatment: Case Series
Authors: Prasetio Renaldi , Harta I Komang Adhi Parama 
Published: February 2022

ABSTRACT

BACKGROUND: Acute on chronic limb ischemia is a condition caused by acute disruption in chronic vessel disease. The major cause is peripheral arterial disease or embolism. Treating the acute phase while considering the origin of disease is important to treat acute on chronic limb ischemia.
CASE DESCRIPTION: 3 cases were described on this serial case report. The first and second case represent acute on chronic limb ischemia conditions with history of intermittent claudication (IC) and signs of acute limb ischemia (ALI) upon arrival. They were both treated with surgical intervention for ALI. Despite of adequate surgical intervention, both cases showed suboptimal limb recovery. Both patients were referred for further evaluation of chronic vessel disease with angiography. Third case represent chronic limb ischemia as end point of treatment from the first and second case. Patient with worsening IC despite adequate medical and exercise treatment underwent angiography examination. Angiography result found two sites of total occlusion of right common iliac artery and superficial femoral artery. Angioplasty and primary stenting were done on common iliac artery. Drug coated balloon and stenting was also performed on superficial femoral artery.
CONCLUSION: Patients with acute on chronic limb ischemia need to be treated during acute phase and the remaining chronic vessel disease. Consideration and care should be taken when managing similar cases for optimal treatment.

KEYWORDS: Acute on chronic limb ischemia, Thrombectomy, Angioplasty, Drug-coated Balloon.
Liver Environment–Imposed Constraints Diversify Movement Strategies of Liver-Localized CD8 T Cells
Authors: Rajakaruna Harshana , O’Connor James H , Cockburn Ian A , Ganusov Vitaly V 
Published: February 2022

Abstract
Pathogen-specific CD8 T cells face the problem of finding rare cells that present their cognate Ag either in the lymph node or in infected tissue. Although quantitative details of T cell movement strategies in some tissues such as lymph nodes or skin have been relatively well characterized, we still lack quantitative understanding of T cell movement in many other important tissues, such as the spleen, lung, liver, and gut. We developed a protocol to generate stable numbers of liver-located CD8 T cells, used intravital microscopy to record movement patterns of CD8 T cells in livers of live mice, and analyzed these and previously published data using well-established statistical and computational methods. We show that, in most of our experiments, Plasmodium-specific liver-localized CD8 T cells perform correlated random walks characterized by transiently superdiffusive displacement with persistence times of 10–15 min that exceed those observed for T cells in lymph nodes. Liver-localized CD8 T cells typically crawl on the luminal side of liver sinusoids (i.e., are in the blood); simulating T cell movement in digital structures derived from the liver sinusoids illustrates that liver structure alone is sufficient to explain the relatively long superdiffusive displacement of T cells. In experiments when CD8 T cells in the liver poorly attach to the sinusoids (e.g., 1 wk after immunization with radiation-attenuated Plasmodium sporozoites), T cells also undergo Lévy flights: large displacements occurring due to cells detaching from the endothelium, floating with the blood flow, and reattaching at another location. Our analysis thus provides quantitative details of movement patterns of liver-localized CD8 T cells and illustrates how structural and physiological details of the tissue may impact T cell movement patterns.
Prevalence and risk factors of myopia amongst Grade 8 learners in the Vhembe district, South Africa
Authors: Tshivhase Shonisani E. , Mashau Ntsieni S. , Mathebula Dephney 
Published: February 2022

Background: Myopia is the most common cause of refractive errors in both adults and children in many countries. However, it is not a simple refractive error but sometimes and eyesight-threatening disorder. The disorder has a great impact on public health and the socio-economic well-being of people, particularly children.Aim: The study aimed to assess the prevalence of myopia amongst secondary school learners.Setting: The study was conducted in the Vhembe District, South Africa.Methods: A cross-sectional study was carried out amongst 297 Grade 8 students of 13 to 14 years of age. The students were selected using a multi-stage-stratified cluster sampling technique from three secondary schools. Two public secondary schools and one private secondary school. The learners’ socioeconomic background, type of school and parental myopia were assessed by a questionnaire before visual acuity assessment. Learners with visual acuity of less than or equal to 6/12 in the worse eye, who showed vision improvement with pinhole, underwent non-cycloplegic retinoscopy and subjective refraction were selected. Myopia was defined as a spherical equivalent of less than or equal to −0.50 dioptre (D). Data were analysed using descriptive statistics.Results: A total of 289 learners completed the study (156 aged 14 years and 133 aged 13 years). A total of 30 learners were identified to have myopic refractive error making the prevalence of 10.4%. Of the 154 females, 14 (47.0%) had myopia, whilst 16 (53.0%) of the 135 males had myopia making males slightly more myopic than females. From the total learners diagnosed to have refractive error (n = 40), myopia constituted 30/40 (75.0%) of the learners indicating that it is the commonest type of refractive error amongst secondary learners. Myopia was more common amongst older age children (14 years; 57.0%). About 18 (60.0%) participants were from the urban area. A total of 17 (57%) of the myopic learners attended private school and about 63% of the participants’ parents were myopic.Conclusion: Spending more time indoor and continuous reading without resting are risk factors of myopia whilst increased outdoor activities were observed as protective environmental factors against myopia in secondary school learners. Doing more outdoors activities may be beneficial to protect against myopia onset.
Long-Term Impact of Global Pediatrics Curriculum, Experience, and Mentorship in Pediatric Residency
Authors: Ojo Ifelayo , Wu Andrew , Lauden Stephanie , Slusher Tina , Gladding Sophia , Danich Emily , Howard Cynthia 
Published: February 2022

ABSTRACT.
Global health education is offered increasingly during residency training. The University of Minnesota has offered a global pediatrics track to residents since 2005. This study aimed to understand the impacts of a global pediatrics track on graduates’ career choices, skills, and current engagement in global health. An electronic survey was sent to 110 track graduates in February to April 2020. Data were analyzed with descriptive statistics and paired t-tests. Content analysis of written comments was conducted. The response rate was 62% overall, varying by question. Overall, 75% of responding graduates reported global pediatrics track participation affected their career choices. Eighty-four percent recalled plans to work in global health after graduation and 64% of respondents reported working in global health abroad or at home at the time of the survey. Incorporation of public health and global research represented the greatest percentage change in career plans from the time of enrollment to graduation (24% and 27%, respectively). Ninety-five percent of respondents reported that track participation improved their ability to elicit information about cultural beliefs and practices, and 86% reported improvement in cost-conscious care. An increase in global health knowledge and skills was the most common category of impact cited by respondents. Neonatal resuscitation, bubble continuous positive airway pressure, and homemade spacers for metered-dose inhalers were the most used global health-adapted skills. Our study found that graduates of the global pediatrics track perceive their participation affected their knowledge, skills, and attitudes positively, with the potential to improve clinical care and promote health equity locally and globally.