Volkov solution for two laser beams and ITER

We find the solution of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an alectron. The practical meaning of the two laser beams is, that two laser beams impinging on a targed which is constituted from material in the form of a foam, can replace 100-200 laser beams impinging on a normal targed. It means that the nuclear fusion with two laser beams is realistic in combination with the nuclear reactor such as ITER.Comment: 13 page

Percutaneous angioplasty for infrainguinal graft-related stenoses

Objective:To assess the success of percutaneous transluminal angioplasty (PTA) in treating infrainguinal graft-related stenoses.Design:Retrospective analysis of stenoses undergoing PTA over 6 years.Materials:Fifty-seven stenoses in 42 grafts.Methods:Site, length and type of stenoses recorded. Follow-up till discharge, graft occlusion or death.Results:PTA was successful in 48/57 stenoses in 36 grafts (G), with a poor result in seven. Further PTA was required in seven stenoses (7 G). One graft occluded at PTA and one stenosis was inaccessible. Overall graft (G) patency (median 13 months) was 82% (1 year patency 84%). Of 48 successful PTAs (37 G), 36 remained patent (28 G), eight (4 G) occluded and four were lost to follow-up (4 G). Fourteen of thirty-six stenoses which remained patent required further intervention (seven PTA, six jump grafts, one vein patch). The four occlusions were associated with small veins (two), multiple stenoses (one) and a PTFE graft which occluded 10 days following PTA. Of the seven PTAs with a poor angiographic result, five remained patent, three after further intervention.Conclusion:PTA is the best treatment for localised stenoses. Stenoses >2 cm or multiple (three or more) stenoses are best treated surgically. Follow-up is essential, as 20% require further intervention

The Neutral Gas Dynamics of the Nearby Magellanic Irregular Galaxy UGCA 105

We present new low-resolution HI spectral line imaging, obtained with the Karl G. Jansky Very Large Array (JVLA), of the star-forming Magellanic irregular galaxy UGCA 105. This nearby (D = 3.39+/-0.25 Mpc), low mass [M_HI=(4.3+/-0.5)x10^8 Solar masses] system harbors a large neutral gas disk (HI radius ~7.2 kpc at the N_HI=10^20 cm^-2 level) that is roughly twice as large as the stellar disk at the B-band R_25 isophote. We explore the neutral gas dynamics of this system, fitting tilted ring models in order to extract a well-sampled rotation curve. The rotation velocity rises in the inner disk, flattens at 72+/-3 km/s, and remains flat to the last measured point of the disk (~7.5 kpc). The dynamical mass of UGCA 105 at this outermost point, (9+/-2)x10^9 Solar masses, is ~10 times as large as the luminous baryonic components (neutral atomic gas and stars). The proximity and favorable inclination (55 degrees) of UGCA 105 make it a promising target for high-resolution studies of both star formation and rotational dynamics in a nearby low-mass galaxy.Comment: The Astronomical Journal, in pres

Deconstructing and Reconstructing. Embracing Alternative Ways of Producing, Classifying and Disseminating Knowledge

U ovom kratkom radu autori se zalažu za temeljito preispitivanje i reorganizaciju proizvodnje znanja. Intelektualna i kulturna nejednakost dio su socioekonomske nejednakosti. Kako možemo stvoriti bolji svijet ako nismo načisto s premisama znanja koje o tom svijetu imamo te načinom na koji se ono proizvodi? Moramo pažljivo razmotriti što je utišano, a što se glasno izgovara, što je zamagljeno, neprimjetno iako je očigledno ili čemu je dano središnje mjesto. Zadatak nije samo jasno razabrati ono što se ukazuje nakon što se iskopaju te duboko ugrađene pretpostavke. Riječ je i o tome da je potrebno stvoriti nove riječi, nove metode i nove institucije koje neće ponoviti iste greške. Zalog je sljedeću generaciju odgojiti drugačije kako bi bila spremna ucrtati novi put za proizvodnju, klasifikaciju i korištenje znanja na konstruktivniji i inkluzivniji način.In this short piece, we argue for a fundamental reconsideration and reorganization of knowledge production. Intellectual and cultural inequality are part and parcel of socioeconomic inequality. How can we create a better world if we are not clear about the premises behind the knowledge that we have about that world and how it is produced? We need to look carefully at what is silenced and what is said out loud; at what is obscured, hiding in plain sight, or given centre stage. Not only is the task at hand to see clearly what comes into view when these embedded assumptions are excavated. It is also to create new words, new methods, and new institutions that do not repeat the same mistakes. It is a plea to train the next generation differently, so they are prepared to chart a new path toward producing, classifying, and using knowledge in more constructive and inclusive ways

A UK wide cohort study describing management and outcomes for infants with surgical Necrotising Enterocolitis

The Royal College of Surgeons have proposed using outcomes from necrotising enterocolitis (NEC) surgery for revalidation of neonatal surgeons. The aim of this study was therefore to calculate the number of infants in the UK/Ireland with surgical NEC and describe outcomes that could be used for national benchmarking and counselling of parents. A prospective nationwide cohort study of every infant requiring surgical intervention for NEC in the UK was conducted between 01/03/13 and 28/02/14. Primary outcome was mortality at 28-days. Secondary outcomes included discharge, post-operative complication, and TPN requirement. 236 infants were included, 43(18%) of whom died, and eight(3%) of whom were discharged prior to 28-days post decision to intervene surgically. Sixty infants who underwent laparotomy (27%) experienced a complication, and 67(35%) of those who were alive at 28 days were parenteral nutrition free. Following multi-variable modelling, presence of a non-cardiac congenital anomaly (aOR 5.17, 95% CI 1.9-14.1), abdominal wall erythema or discolouration at presentation (aOR 2.51, 95% CI 1.23-5.1), diagnosis of single intestinal perforation at laparotomy (aOR 3.1 95% CI 1.05-9.3), and necessity to perform a clip and drop procedure (aOR 30, 95% CI 3.9-237) were associated with increased 28-day mortality. These results can be used for national benchmarking and counselling of parents

Discovery of a Disrupting Open Cluster Far into the Milky Way Halo: A Recent Star Formation Event in the Leading Arm of the Magellanic Stream?

We report the discovery of a young (tau similar to 117 Myr), low-mass (M similar to 1200 M.), metal-poor ([Fe H] similar to -1.14) stellar association at a heliocentric distance D approximate to 28.7 kpc, placing it far into the Milky Way (MW) halo. At its present Galactocentric position (R, z) similar to (23, 15) kpc, the association is (on the sky) near the leading arm of the gas stream emanating from the Magellanic Cloud system, but is located approximate to 60 degrees from the Large Magellanic Cloud center on the other side of the MW disk. If the cluster is colocated with H I gas in the stream, we directly measure the distance to the leading arm of the Magellanic stream. The measured distance is inconsistent with Magellanic stream model predictions that do not account for ram pressure and gas interaction with the MW disk. The estimated age of the cluster is consistent with the time of last passage of the leading arm gas through the Galactic midplane; we therefore speculate that this star formation event was triggered by its last disk midplane passage. Most details of this idea remain a puzzle: the Magellanic stream has low column density, the MW disk at large radii has low gas density, and the relative velocity of the leading arm and MW gas is large. However it formed, the discovery of a young stellar cluster in the MW halo presents an interesting opportunity for study. This cluster was discovered with Gaia astrometry and photometry alone, but follow-up DECam photometry was crucial for measuring its properties.National Science Foundation (NSF) [AST-1813881]; Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory (NOAO) [2018A-0251]; Center for Computational AstrophysicsThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

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

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 middle-income 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 low-income 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 low-income, 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

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