Bifurcation of drift shells near the dayside magnetopause

Close to the dayside magnetopause, there is a region of space where each field line has two magnetic field minima, one near each cusp. That region is located around local noon, and extends about 1-2 R-e from the magnetopause. Particles that enter this region with equatorial pitch angles sufficiently close to 90 degrees will cross the dayside not along an equatorial path, but along one of the two branches on either side of the equatorial plane. The two branches are joined again past local noon. This process of drift-shell bifurcation (DSB) is nonadiabatic even under static conditions. Two physical mechanisms can cause this nonadiabaticity: one that is operative for nearly all magnetospheric magnetic field configurations and another that depends on a particular combination of north-south and east-west asymmetry in the magnetic field. This paper deals only with the first mechanism. For configurations with north-south and east-west symmetry, DSB changes the second invariant I of the motion by a small amount that is of the order of the gyroradius (the first invariant is intact). For near-equatorial particles (I approximate to 0) the change can be significantly larger. Assuming north-south and dawn-dusk symmetry, we present general theoretical expressions for the second-invariant jump Delta I, which can be applied to a variety of magnetic field models. The results show that Delta I is sensitively dependent on the bounce phase of the particle at the bifurcation line. The RMS value of Delta I over a bounce-phase ensemble increases with decreasing mirror field and with increasing kinetic energy. We verify these results with test-particle simulations using model magnetic fields.Publisher's Versio

An Analysis of Graduate Theses on Early Childhood Education: The Case of Turkey

The primary concern of this study is to reveal the general tendencies (genders of the authors/supervisors, change in the number of graduate theses by year, number of research problems-results-suggestions, focal points, the corpus by research models/methods, data collection meth-ods/tools, and population/sample group) of graduate on early childhood education in Turkey between 2005 and 2017. The sampling of the present research study consists of 182 graduate theses. The study relies on the retrieval of the desired data by document analysis through a systematic examination of the available theses by using a thesis examination form developed by the researchers. The results revealed that 85% of the authors were female and almost half of the supervisors were assistant professors and moreover 59% of the supervisors were female. The study also showed that a great majority of the examined theses contained 0-10 research problems, results and suggestions. It was also fig-ured out in the study that the focal point of the thesesis majorly qualifications of preschool teachers, characteristics and tendencies of parents, effects of different approaches/methods on early childhood education, characteristics of children in early childhood education or at preschool age. It was observed that 68.1% of graduate theses were quantitative studies and that the least employed research method was observation (0.5%), case study (1.1%), interview (1.6%) and phenomenological method (1.6%), while the most frequently administered data collection tool, accounting for 65%, was questionnaire

Parallelized preconditioned model building algorithm for matrix factorization

Matrix factorization is a common task underlying several machine learning applications such as recommender systems, topic modeling, or compressed sensing. Given a large and possibly sparse matrix A, we seek two smaller matrices W and H such that their product is as close to A as possible. The objective is minimizing the sum of square errors in the approximation. Typically such problems involve hundreds of thousands of unknowns, so an optimizer must be exceptionally efficient. In this study, a new algorithm, Preconditioned Model Building is adapted to factorize matrices composed of movie ratings in the MovieLens data sets with 1, 10, and 20 million entries. We present experiments that compare the sequential MATLAB implementation of the PMB algorithm with other algorithms in the minFunc package. We also employ a lock-free sparse matrix factorization algorithm and provide a scalable shared-memory parallel implementation. We show that (a) the optimization performance of the PMB algorithm is comparable to the best algorithms in common use, and (b) the computational performance can be significantly increased with parallelizatio

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Evaluation of genial tubercle anatomy using cone beam computed tomography

WOS: 000356203400013PubMed ID: 26062865The purpose of this study was to characterize the anatomy of the genial tubercle using cone beam computed tomography (CBCT). The morphology and detailed anatomy of the genial tubercle were assessed retrospectively in 201 patients (101 females, 100 males) using CBCT images. The parameters examined were the height (GH) and width (GW) of the genial tubercle, the distance from the lower incisors to the superior border of the tubercle (I-SGT), the distance from the inferior margin of the tubercle to the inferior margin of the mandible (IGM-IBM), and the anterior mandible thickness (AMT). Statistical analysis was performed to assess relationships among these parameters, gender, and orthodontic malocclusion (P 0.05). However, IGM-IBM was larger for class III than for class I and class II male patients, and larger than for class I female patients. AMT in class III patients was greater than in class I and II patients (P < 0.05). The use of CBCT, which employs less radiation, is important for dental professionals, especially those performing surgery for obstructive sleep apnea (OSA), in order to avoid possible surgical complications

Parallelized preconditioned model building algorithm for matrix factorization

Matrix factorization is a common task underlying several machine learning applications such as recommender systems, topic modeling, or compressed sensing. Given a large and possibly sparse matrix A, we seek two smaller matrices W and H such that their product is as close to A as possible. The objective is minimizing the sum of square errors in the approximation. Typically such problems involve hundreds of thousands of unknowns, so an optimizer must be exceptionally efficient. In this study, a new algorithm, Preconditioned Model Building is adapted to factorize matrices composed of movie ratings in the MovieLens data sets with 1, 10, and 20 million entries. We present experiments that compare the sequential MATLAB implementation of the PMB algorithm with other algorithms in the minFunc package. We also employ a lock-free sparse matrix factorization algorithm and provide a scalable shared-memory parallel implementation. We show that (a) the optimization performance of the PMB algorithm is comparable to the best algorithms in common use, and (b) the computational performance can be significantly increased with parallelization

Chitosan-coated alginate membranes for cultivation of limbal epithelial cells to use in the restoration of damaged corneal surfaces

Some chemicals or thermal burns may result in abnormal reepithelialization by conjunctival epithelial cells and it causes different types of damage on the cornea surface: When reepithelialization does not occur, chronic inflammation and neovascularization develop, often leading to stroma scarring and/or ulceration. The aim of this study is to restore the human corneal surface with autologous corneal epithelial sheets generated by serial cultivation of the limbal epithelial cells over the different compositions of composite membranes. The composite membranes were prepared by coating the alginate membrane with chitosan. In this method, alginate membrane was prepared by precipitation of the sodium alginate solution in calcium chloride solution. Alginate membranes were washed; dried anti immersed into the chitosan solutions to prepare composite membranes. The composite membranes were characterized based on their morphology, hydrophilicity, swellability, and chemical structure. In the last part of the study, composite membranes were used as base matrices for limbal epithelial cell cultivation. The cell cultivation on polymeric membranes was investigated as the in vitro studies. In these studies cell attachment, spreading and growth on polymeric membranes were evaluated

EGF loaded chitosan sponges as wound dressing material

The aim of this study was to prepare and characterize chitosan sponges using epidermal growth factor (EGF) for wound healing. Chitosan sponges were prepared by solvent evaporation (or precipitation) combined with chemical cross-linking techniques. The chitosan polymer was weighed and dissolved in aqueous acetic acid solution (5% v/v) and injected into absolute ethanol containing a cross-linker (ethylene glycol diglycydyl ether). The growth factor (EGF) was loaded into sponges by adding it into the chitosan solution. The EGF loaded chitosan sponges were used in fibroblast cell culture studies to investigate the effects of EGF released on cell proliferation and to determine the effects of the different variables on EGF release; such as, chitosan Mw, crosslinker, the needle injecting the chitosan solution into the precipitation medium, chitosan/EGF ratio and pH of the medium. The swelling of the sponges was higher in the lower molecular weight chitosan, with less cross-linker and using a small diameter injection needle. The swelling increased with decreasing chitosan/EGF ratio and the EGF release rate was increased by increasing the sponge swelling. The cell proliferation (cell growth) increased with increasing swelling ratio

An unusual complication of posterior packing in epistaxis

WOS: 000434665900014PubMed ID: 30374485Endonasal or transnasal procedures are sometimes necessary in patients with head trauma. Before these procedures, the integrity of the skull base must be considered to avoid penetration of the cranial vault. A 54-year-old man was taken to a district hospital following a car accident. After the initial assessment and emergency treatment, he was transferred to our emergency clinic for further examination. The patient had massive nasal bleeding, though a Foley catheter had been inserted to control posterior bleeding. Computed tomography (CT) revealed that the catheter was not positioned correctly and was in the cranial vault. Several fractures of the maxillofacial and cranial bones and cervical vertebrae were detected on CT. He also had right hemothorax and bilateral brain contusions. Endonasal insertion of catheters or tubes in trauma patients without a complete assessment of the skull base can cause serious complications