Magnetic Flux Transport at the Solar Surface

After emerging to the solar surface, the Sun's magnetic field displays a complex and intricate evolution. The evolution of the surface field is important for several reasons. One is that the surface field, and its dynamics, sets the boundary condition for the coronal and heliospheric magnetic fields. Another is that the surface evolution gives us insight into the dynamo process. In particular, it plays an essential role in the Babcock-Leighton model of the solar dynamo. Describing this evolution is the aim of the surface flux transport model. The model starts from the emergence of magnetic bipoles. Thereafter, the model is based on the induction equation and the fact that after emergence the magnetic field is observed to evolve as if it were purely radial. The induction equation then describes how the surface flows -- differential rotation, meridional circulation, granular, supergranular flows, and active region inflows -- determine the evolution of the field (now taken to be purely radial). In this paper, we review the modeling of the various processes that determine the evolution of the surface field. We restrict our attention to their role in the surface flux transport model. We also discuss the success of the model and some of the results that have been obtained using this model.Comment: 39 pages, 15 figures, accepted for publication in Space Sci. Re

Sporopollenin, a natural copolymer, is robust under high hydrostatic pressure

Lycopodium sporopollenin, a natural copolymer, shows exceptional stability under high hydrostatic pressures (10 GPa) as determined by in situ high pressure synchrotron source FTIR spectroscopy. This stability is evaluated in terms of the component compounds of the sporopollenin: p-coumaric acid, phloretic acid, ferulic acid, and palmitic and sebacic acids, which represent the additional n-acid and ndiacid components. This high stability is attributed to interactions between these components, rather than the exceptional stability of any one molecular component. We propose a biomimetic solution for the creation of polymer materials that can withstand high pressures for a multitude of uses in aeronautics, vascular autografts, ballistics and light-weight protective materials

A guanosine 5′-triphosphate-dependent protein kinase is localized in the outer envelope membrane of pea chloroplasts

A guanosine 5-triphosphate (GTP)-dependent protein kinase was detected in preparations of outer chloroplast envelope membranes of pea (Pisum sativum L.) chloroplasts. The protein-kinase activity was capable of phosphorylating several envelope-membrane proteins. The major phosphorylated products were 23- and 32.5-kilo-dalton proteins of the outer envelope membrane. Several other envelope proteins were labeled to a lesser extent. Following acid hydrolysis of the labeled proteins, most of the label was detected as phosphoserine with only minor amounts detected as phosphothreonine. Several criteria were used to distinguish the GTP-dependent protein kinase from an ATP-dependent kinase also present in the outer envelope membrane. The ATP-dependent kinase phosphorylated a very different set of envelope-membrane proteins. Heparin inhibited the GTP-dependent kinase but had little effect upon the ATP-dependent enzyme. The GTP-dependent enzyme accepted phosvitin as an external protein substrate whereas the ATP-dependent enzyme did not. The outer membrane of the chloroplast envelope also contained a phosphotransferase capable of transferring labeled phosphate from [-32P]GTP to ADP to yield (-32P]ATP. Consequently, addition of ADP to a GTP-dependent protein-kinase assay resulted in a switch in the pattern of labeled products from that seen with GTP to that typically seen with ATP

Population, sexual and reproductive health, rights and sustainable development: forging a common agenda.

This article suggests that sexual and reproductive health and rights activists seeking to influence the post-2015 international development paradigm must work with sustainable development advocates concerned with a range of issues, including climate change, environmental issues, and food and water security, and that a way of building bridges with these communities is to demonstrate how sexual and reproductive health and rights are relevant for these issues. An understanding of population dynamics, including urbanization and migration, as well as population growth, can help to clarify these links. This article therefore suggests that whether or not sexual and reproductive health and rights activists can overcome resistance to discussing "population", become more knowledgeable about other sustainable development issues, and work with others in those fields to advance the global sustainable development agenda are crucial questions for the coming months. The article also contends that it is possible to care about population dynamics (including ageing and problems faced by countries with a high proportion of young people) and care about human rights at the same time. It expresses concern that, if sexual and reproductive health and rights advocates do not participate in the population dynamics discourse, the field will be left free for those for whom respecting and protecting rights may be less of a priority

Designing Efficient Taxi Pickup Operations at Airports

This paper provides a practical procedure for designing efficient taxi pickup operations at airports. How to do this effectively is an open question. Solutions are not available, and practices vary. They reflect different approaches to and lack of research on the subject. The solutions are often unsatisfactory. At many airports, passengers routinely suffer long waits outdoors, exposed to the elements, after a tiring journey. Such disagreeable experiences are avoidable. Designing efficient taxi pickup operations at airports is problematic. The peculiarities of the process preclude easy solutions. First, the process involves queuing, so system performance is a nonlinear function of the loads. Second, it features unstable transient situations, since travelers typically arrive in bulk over short periods. Third, traffic is significantly differentiated and consists of a wide variety of groups implying different service characteristics. Standard results from queuing theory thus do not have a useful application to this problem. The design process uses simulation that is based on detailed observation of local practices. It involves four steps: (a) detailed local measurements of the arrival of both travelers and taxis, and the service rates provided by taxis in different queuing positions; (b) creation and validation of a simulation model sufficiently detailed to account for these realities; (c) exploration of design alternatives to estimate the characteristics of the service they would provide; and (d) selection of a preferred design that properly balances efforts to minimize average and extreme wait times. The paper demonstrates the procedure through application to Lisbon International Airport, Portugal.SIMUL8 Corporatio

Subsurface Flows in and Around Active Regions with Rotating and Non-rotating Sunspots

The temporal variation of the horizontal velocity in subsurface layers beneath three different types of active regions is studied using the technique of ring diagrams. In this study, we select active regions (ARs) 10923, 10930, 10935 from three consecutive Carrington rotations: AR 10930 contains a fast-rotating sunspot in a strong emerging active region while other two have non-rotating sunspots with emerging flux in AR 10923 and decaying flux in AR 10935. The depth range covered is from the surface to about 12 Mm. In order to minimize the influence of systematic effects, the selection of active and quiet regions is made so that these were observed at the same heliographic locations on the solar disk. We find a significant variation in both components of the horizontal velocity in active regions as compared to quiet regions. The magnitude is higher in emerging-flux regions than in the decaying-flux region, in agreement with earlier findings. Further, we clearly see a significant temporal variation in depth profiles of both zonal and meridional flow components in AR 10930, with the variation in the zonal component being more pronounced. We also notice a significant influence of the plasma motion in areas closest to the rotating sunspot in AR 10930 while areas surrounding the non-rotating sunspots in all three cases are least affected by the presence of the active region in their neighborhood.Comment: Solar Physics (in press), includes 11 figure

Impact of Variant Donor Hepatic Arterial Anatomy on Clinical Graft Outcomes in Liver Transplantation

Standard hepatic arterial anatomy is composed of the common hepatic artery proceeding from the celiac trunk and giving rise to the gastroduodenal artery (GDA) and proper hepatic arteries. Reconstruction of the hepatic arterial supply during liver transplantation, often complex in nature, can be required in cases of accessory or replaced vessels. A recent review summarized the hepatic arterial anatomy reported in over 19,000 cases from 20 individual studies. (1) It has been suggested that the presence of nonstandard donor arterial anatomy may be related to an increased incidence of hepatic artery thrombosis (HAT).(2) Although the overall incidence of HAT is low, it can have devastating effects, including the need for retransplantation, long-term biliary complications, and increased patient mortality. This article describes the arterial anatomy in a large number of liver transplants, with routine anastomosis of a very short hepatic artery and routine reconstruction of the accessory right hepatic artery to the GDA. Study outcomes include incidence of HAT within 30 days of transplant, early graft loss up to 1 year after transplant, and 10-year graft survival

Is female psychopathy linked with child abuse? An empirical investigation using a person-centered approach

Childhood abuse is associated with increased psychopathic features among girls, but most prior research is based on data from correctional samples of female delinquents and less is known about how specific forms of childhood abuse affect specific features of psychopathy. Using a school-based community sample of 696 girls aged 9–17 years from Barbados and Grenada, the current study examined latent profiles of psychopathic personality traits and their associations with physical, emotional, and sexual abuse. Latent profile analysis (LPA) revealed four distinct psychopathy groups among girls, including a ‘low psychopathy’ group (41.9% of girls), ‘high psychopathy’ group (4.8%), ‘high interpersonal manipulation and egocentricity’ group (37.4%), and a ‘moderate psychopathy’ group (16%). There was considerable evidence of physical abuse, emotional abuse, and sexual abuse among participants. Sexual abuse was associated with a 116% increased likelihood of membership in the high psychopathy group and a 57% increased likelihood of membership in the high interpersonal manipulation and egocentricity group. These results indicate that sexual abuse is a powerful distal factor in the development of psychopathic personality functioning, especially more severe variants

Postoperative Atrial Fibrillation and Flutter in Liver Transplantation: An Important Predictor of Early and Late Morbidity and Mortality

Postoperative atrial fibrillation/flutter (POAF) is the most common perioperative arrhythmia and may be particularly problematic after liver transplantation (LT). This study is a single‐center retrospective analysis of POAF to determine its incidence following LT, to identify risk factors, to assess its impact on clinical outcomes, and to summarize management strategies. The records of all patients who underwent LT between 2010 and 2018 were reviewed. Extracted data included pre‐LT demographics and cardiac evaluation, in‐hospital post‐LT cardiac events, early and late complications, and survival. Among 1011 patients, the incidence of post‐LT POAF was 10%. Using binary logistic regression, pre‐LT history of atrial fibrillation was the strongest predictor of POAF (odds ratio [OR], 6.72; 95% confidence interval [CI], 2.00‐22.57; P < 0.001), followed by history of coronary artery disease (CAD; OR, 2.52; 95% CI, 1.10‐5.81; P = 0.03). Cardiac stress testing abnormality and CAD on cardiac catheterization were also associated with higher risk. Median time to POAF onset after LT was 3 days with 72% of cases resolving within 48 hours. POAF patients had greater hospital length of stay, death during the LT admission, and 90‐day and 1‐year mortality. POAF was an independent risk factor for post‐LT mortality (OR, 2.0; 95% CI, 1.3‐3.0; P < 0.01). Amiodarone was administered to 73% of POAF patients with no evidence of increased serum alanine aminotransferase levels. POAF occurred in 10% of post‐LT patients with early onset and rapid resolution in most affected patients. POAF patients, however, had significant morbidity and mortality, suggesting that POAF is an important marker for worse early and late post‐LT outcomes