Isostaticity and the solidification of semiflexible polymer melts

Using molecular dynamics simulations of a tangent-soft-sphere bead-spring polymer model, we examine the degree to which semiflexible polymer melts solidify at isostaticity. Flexible and stiff chains crystallize when they are isostatic as defined by appropriate degree-of-freedom-counting arguments. Semiflexible chains also solidify when isostatic if a generalized isostaticity criterion that accounts for the slow freezing out of configurational freedom as chain stiffness increases is employed. The dependence of the average coordination number at solidification $Z(T_s)$ on chains' characteristic ratio $C_\infty$ has the same functional form [$Z \simeq a - b\ln(C_\infty)$] as the dependence of the average coordination number at jamming $Z(\phi_J)$ on $C_\infty$ in athermal systems, suggesting that jamming-related phenomena play a significant role in thermal polymer solidification

Fair Values: A Framework For Teaching The Standards On Accounting For Financial Instruments

This paper presents a conceptual framework for an integration of financial reporting objectives and principles related to financial instruments.  We believe this integrated approach to be a superior strategy for discussing this diverse and challenging topic.  In our experience, the typical piecemeal coverage of individual instruments scattered in financial accounting texts and other literature is not effective in providing students with a critical appreciation of the evolution in financial reporting requirements in this area. Our approach in this paper is to classify financial instruments into groups according to their special characteristics as a basis for understanding their relevant financial reporting attributes.  Within this conceptual framework, we then present a synthesis of reporting objectives and existing FASB pronouncements on financial instruments.  Using this framework as a roadmap, students should be able to study current and emerging pronouncements in a conceptually organized and integrated fashion. 

What are the opportunities for manufacturing in the “one belt one road” initiative? The case of Hong Kong’s textiles and clothing sector

The One Belt, One Road (hereafter OBOR) initiative is a development strategy launched by China in 2015. Its aim is to increase economic co-operation among countries along the China’s Silk Road Economic Belt and 21st Century Maritime Silk Road that connect Asia, Europe and Africa. As one of China’s important economic drivers, Hong Kong’s anticipated gains taking part in this initiative are substantial. This is particularly true for companies in the textiles and clothing (T&C) sectors, as the OBOR initiative offers investment opportunities in developing low-cost production bases in developing countries and promotes global trade. The main objective of this paper is twofold. First, it investigates how Hong Kong can strengthen its “superconnector” role, facilitating sustainable trade and development in the T&C industries among some OBOR countries. Specific measures are identified so that T&C companies in Hong Kong can establish and facilitate technological upgrades and transformation to potential production facilities in some developing countries under the OBOR initiative. This would contribute to the sustainable development of the T&C sectors in Hong Kong. Second, the study extends the gravity trade model to analyze the development of T&C trade patterns between Hong Kong and OBOR countries. Especially it covered some of the key factors not considered in previous studies, such as Logistics Performance Index (LPI), demographical factors, and those related to the business environment and policies. The analysis covers the impacts of country-specific, social, economic and supply chain factors on T&C trade. Based on the results, recommendations are provided to address how Hong Kong helps to facilitate trade and development of the T&C sectors under the OBOR initiative

Vector lattice model for stresses in granular materials

A vector lattice model for stresses in granular materials is proposed. A two dimensional pile built by pouring from a point is constructed numerically according to this model. Remarkably, the pile violates the Mohr Coulomb stability criterion for granular matter, probably because of the inherent anisotropy of such poured piles. The numerical results are also compared to the earlier continuum FPA model and the (scalar) lattice $q$-model

#Bieber + #Blast = #BieberBlast: Early Prediction of Popular Hashtag Compounds

Compounding of natural language units is a very common phenomena. In this paper, we show, for the first time, that Twitter hashtags which, could be considered as correlates of such linguistic units, undergo compounding. We identify reasons for this compounding and propose a prediction model that can identify with 77.07% accuracy if a pair of hashtags compounding in the near future (i.e., 2 months after compounding) shall become popular. At longer times T = 6, 10 months the accuracies are 77.52% and 79.13% respectively. This technique has strong implications to trending hashtag recommendation since newly formed hashtag compounds can be recommended early, even before the compounding has taken place. Further, humans can predict compounds with an overall accuracy of only 48.7% (treated as baseline). Notably, while humans can discriminate the relatively easier cases, the automatic framework is successful in classifying the relatively harder cases.Comment: 14 pages, 4 figures, 9 tables, published in CSCW (Computer-Supported Cooperative Work and Social Computing) 2016. in Proceedings of 19th ACM conference on Computer-Supported Cooperative Work and Social Computing (CSCW 2016

Mass spectrometry imaging identifies palmitoylcarnitine as an immunological mediator during Salmonella Typhimurium infection

Salmonella Typhimurium causes a self-limiting gastroenteritis that may lead to systemic disease. Bacteria invade the small intestine, crossing the intestinal epithelium from where they are transported to the mesenteric lymph nodes (MLNs) within migrating immune cells. MLNs are an important site at which the innate and adaptive immune responses converge but their architecture and function is severely disrupted during S. Typhimurium infection. To further understand host-pathogen interactions at this site, we used mass spectrometry imaging (MSI) to analyse MLN tissue from a murine model of S. Typhimurium infection. A molecule, identified as palmitoylcarnitine (PalC), was of particular interest due to its high abundance at loci of S. Typhimurium infection and MLN disruption. High levels of PalC localised to sites within the MLNs where B and T cells were absent and where the perimeter of CD169+ sub capsular sinus macrophages was disrupted. MLN cells cultured ex vivo and treated with PalC had reduced CD4+CD25+ T cells and an increased number of B220+CD19+ B cells. The reduction in CD4+CD25+ T cells was likely due to apoptosis driven by increased caspase-3/7 activity. These data indicate that PalC significantly alters the host response in the MLNs, acting as a decisive factor in infection outcome

Dosage Compensation in the Mouse Balances Up-Regulation and Silencing of X-Linked Genes

Dosage compensation in mammals involves silencing of one X chromosome in XX females and requires expression, in cis, of Xist RNA. The X to be inactivated is randomly chosen in cells of the inner cell mass (ICM) at the blastocyst stage of development. Embryonic stem (ES) cells derived from the ICM of female mice have two active X chromosomes, one of which is inactivated as the cells differentiate in culture, providing a powerful model system to study the dynamics of X inactivation. Using microarrays to assay expression of X-linked genes in undifferentiated female and male mouse ES cells, we detect global up-regulation of expression (1.4- to 1.6-fold) from the active X chromosomes, relative to autosomes. We show a similar up-regulation in ICM from male blastocysts grown in culture. In male ES cells, up-regulation reaches 2-fold after 2–3 weeks of differentiation, thereby balancing expression between the single X and the diploid autosomes. We show that silencing of X-linked genes in female ES cells occurs on a gene-by-gene basis throughout differentiation, with some genes inactivating early, others late, and some escaping altogether. Surprisingly, by allele-specific analysis in hybrid ES cells, we also identified a subgroup of genes that are silenced in undifferentiated cells. We propose that X-linked genes are silenced in female ES cells by spreading of Xist RNA through the X chromosome territory as the cells differentiate, with silencing times for individual genes dependent on their proximity to the Xist locus

Health workers' views on quality of prevention of mother-to-child transmission and postnatal care for HIV-infected women and their children

<p>Abstract</p> <p>Background</p> <p>Prevention of mother-to-child transmission has been considered as not a simple intervention but a comprehensive set of interventions requiring capable health workers. Viet Nam's extensive health care system reaches the village level, but still HIV-infected mothers and children have received inadequate health care services for prevention of mother-to-child transmission. We report here the health workers' perceptions on factors that lead to their failure to give good quality prevention of mother-to-child transmission services.</p> <p>Methods</p> <p>Semistructured interviews with 53 health workers and unstructured observations in nine health facilities in Hanoi were conducted. Selection of respondents was based on their function, position and experience in the development or implementation of prevention of mother-to-child transmission policies/programmes.</p> <p>Results</p> <p>Factors that lead to health workers' failure to give good quality services for prevention of mother-to-child transmission include their own fear of HIV infection; lack of knowledge on HIV and counselling skills; or high workloads and lack of staff; unavailability of HIV testing at commune level; shortage of antiretroviral drugs; and lack of operational guidelines. A negative attitude during counselling and provision of care, treating in a separate area and avoidance of providing service at all were seen by health workers as the result of fear of being infected, as well as distrust towards almost all HIV-infected patients because of the prevailing association with antisocial behaviours. Additionally, the fragmentation of the health care system into specialized vertical pillars, including a vertical programme for HIV/AIDS, is a major obstacle to providing a continuum of care.</p> <p>Conclusion</p> <p>Many hospital staff were not being able to provide good care or were even unwilling to provide appropriate care for HIV-positive pregnant women The study suggests that the quality of prevention of mother-to-child transmission service could be enhanced by improving communication and other skills of health workers, providing them with greater support and enhancing their motivation. Reduction of workload would also be important. Development of a practical strategy is needed to strengthen and adapt the referral system to meet the needs of patients.</p

СПЕКТРАЛЬНО-ВРЕМЕННАЯ ДИНАМИКА НЕСТАЦИОНАРНОГО ПОГЛОЩЕНИЯ МНОГОСЛОЙНЫХ ПЕРИОДИЧЕСКИХ ПЛАЗМОННЫХ НАНОСТРУКТУР

The features of the induced changes in the optical density spectra of multilayer Ag-Na3 AlF6 nanostructures under a femtosecond laser pulses exitation in the band of surface plasmonic resonance of absorption (SPRA) were studied. The dependence of the amplitude of the induced changes on the thickness of the dielectric Na3 AlF6 films separating the monolayeres of silver nanoparticles was registered. A significant increase of the optical response amplitude (up to 80 %) was found for the nanostructures with the quarter-wavelength Na3 AlF6 interlayers. For nanostructures with different-thickness dielectric Na3 AlF6 interlayers the characteristic relaxation times of induced changes at an excitation energy of 5–10 μJ do not practically vary, are equal to ~2 ps and coincide with the kinetic response time parameters of the used silver nanoparticle monolayers. Изучены особенности наведенных изменений в спектрах оптической плотности многослойных наноструктур Ag-Na3 AlF6 при их возбуждении фемтосекундными лазерными импульсами в полосе плазмонного поверхностного резонанса поглощения (ППРП). Зарегистрирована зависимость амплитуды наведенных изменений в области ППРП от толщины диэлектрических пленок Na3 AlF6 , разделяющих монослои наночастиц серебра. Обнаружено существенное увеличение амплитуды оптического отклика (до 80 %) для наноструктуры с четвертьволновыми прослойками Na3 AlF6 . Характеристические времена релаксации наводимых изменений при энергиях возбуждения 5–10 мкДж для наноструктур с различной толщиной диэлектрических прослоек Na3 AlF6 практически не изменяются, составляют ~2 пс и совпадают с временными параметрами кинетического отклика, характерными для используемого монослоя наночастиц Ag.