bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Repeated Sprint Ability of Amateur Football Players According to Age and Playing Positions
Authors: Can Ibrahim
Published: April 2018

The purpose of this study is to compare the repeated sprint ability of amateur footbal players according to age andplaying positions. For this purpose, 174 young amateur soccer players (age: 17.2±1.8 years, height: 175.8±7.5 cm,weight: 67.0±9.8 kg) struggling in different playing positions participated voluntarily to the study. The players dividedinto six categories as goalkeepers (n: 16; age: 17.4±1.4 years, height: 181.9±6.1 cm, weight: 77.4±9.8 kg), centraldefenders (n: 30; age: 16.9±1.9 years, height: 179.3±8.2 weight: 69.5±11.2 kg), full-backs (n: 34; age: 17.3±1.9 years,height: 174.9±5.9 cm, weight: 66.6±7.8 kg), central midfielders (n: 36; age: 17.9±1,6 years; height: 174.3±7.1 cm;weight: 67.1±9.3 kg), wide midfielders (n: 30; age: 16.8±1.6 years, height: 171.5± 5.1 cm, weight: 60.8±7.4 kg) andforwards (n: 28; age: 16.6±1.9 years, height: 175.9±8.3 cm, weight: 65.6±8.0 kg). In the study, a repeated sprint testwas used to determine the repeated sprint ability of the football players, with an in field 34.2 meter long sprint run anda 25 second rest period after each run. In evaluating the data; descriptive statistics, one-way ANOVA andkruskal-wallis tests were used. According to the analysis results; the best test time (BTT), mean test time (MTT), andtotal test time (TTT) values in the repeated sprint test showed a statistically significant difference according to playingpositions and age factor (p<.05); On the other hand, fatigue index (FI) value showed a statistically significantdifference according to playing positions (p<.05), but it didn’t show any significant difference according to age (p>.05).As a result, it can be argued that repeated sprint ability differs according to age and playing positions.
Universal Design for Learning to Support Access to the General Education Curriculum for Students with Intellectual Disabilities
Authors: Al Hazmi Adnan Nasser , Ahmad Aznan Che
Published: April 2018

The issue concerned with enhancing support to the intellectually disabled students for enabling them to access thegeneral education has gained significant importance in the recent years all over the world. The intellectually disabledstudents suffer from neurodevelopmental disorders that acts as a barrier to the normal functioning of the brain andslow down the learning abilities and proper development of an individual. The presence of intellectual disabilitiesaffects both the mental and physical well-being of the students by causing issues for them to understand, thinklogically, speak, remembering things, and find solutions to the problems. Many research studies are conducted acrossthe world for finding the ways and designing innovative models that can help in increasing the access to generaleducation for these students with special needs. The universal design for learning framework also aims at providingsupport to the intellectually disabled students for gaining access to general education by enhancing their intellectualfunctioning and ability to adapt.
Peer Observation: A Professional Learning Tool for English Language Teachers in an EFL Institute
Authors: Ahmed Ejaz , Nordin Zaimuariffudin Shukri , Shah Sayyed Rashid , Channa Mansoor Ahmed
Published: April 2018

The key aim of this study is to explore the perceptions of English as foreign language (EFL) teachers about peerobservation as a tool for professional development that is implemented in an English Language Institute of a SaudiArabian university. This paper reviews literature on peer observation to develop a conceptual and theoreticalunderstanding of peer observation systems in different contexts. It utilizes a mix-method approach and applies aquestionnaire and semi-structured interviews as data collection tools. Questionnaire is used to get information aboutEFL teachers’ perceptions whereas semi-structured interviews provide an insight into their practices in the form ofpeer observation and future amendments for PD. The participants share their lived experiences who consider thecurrent practice of peer observation a consistent professional challenge due to several factors, i.e. their lack ofautonomy in deciding about the peers, trust deficit between administration and EFL teachers, rarely heldpre-observation conferences due to the loads of teaching hours, observers’ insufficient training and qualifications inconducting PO, and the element of threat and insecurity. Based on the findings, recommendations are made toimprove the existing peer observation system for the benefit of the EFL teachers, English language learners and theinstitute.
Desdobramentos do Programa Territórios da Cidadania no Nordeste Paraense: desenvolvimento ou controle social?
Authors: Silva Arthur Boscariol da
Published: April 2018

No contexto da implementação das políticas públicas territoriais no Brasil, o Programa Territórios da Cidadania é apresentado como uma nova forma de gestão do território pautada na delimitação de áreas semelhantes contando com a participação da sociedade civil organizada. A proposta se anuncia como inovadora, no entanto, acompanha princípios do desenvolvimento anteriormente aplicado. Os documentos oficiais que sugerem mudanças nas ações estatais, mas são desacompanhadas das mecanismos que viabilizem seu funcionamento. Assim, através da análise funcionamento do Programa no território Nordeste Paraense, com foco em suas realizações materiais, a presente dissertação buscou desvendar a concepção de desenvolvimento norteadora das ações realizadas, contrapondo seu discurso à sua prática.
A territorialidade e o território na obra de Robert David Sack
Authors: Soares Junior Amilton Quintela , Santos Mauro Augusto
Published: April 2018

Um dos autores mais citados em trabalhos científicos que abordam a temática territorial, Robert David Sack é constantemente mencionado, de maneira superficial, com base nos conceitos iniciais de território e territorialidade humana apresentados em Human Territoriality: Its theory and history. A obra, que ainda não foi traduzida oficialmente para o português, é o foco do presente artigo, que busca produzir uma síntese da teoria de Sack e uma relação entre seus conteúdos e a visão de outros autores, explorando aspectos potencialmente mais profundos e demonstrando a sua importante contribuição para a compreensão da territorialidade como estratégia espacial de controle e influência, capaz de produzir efeitos e combinações de efeitos que impactam diretamente as relações entre as pessoas e os fenômenos que se manifestam em um território.
Distal Femoral Varus Osteotomy for the Management of Valgus Deformity of the Knee
Authors: Sherman Seth L. , Thompson Samuel F. , Clohisy John C. F.
Published: April 2018

Distal femoral varus osteotomy is a well-described treatment option for patients with valgus malalignment associated with a variety of underlying conditions. This procedure may be the definitive treatment option in active patients with isolated lateral compartment osteoarthritis or posttraumatic arthritis. It may be a useful concomitant procedure in young patients with lateral meniscus deficiency, focal chondral defects, chronic medial collateral ligament insufficiency, and/or patellofemoral instability. Distal femoral varus osteotomy can be performed with medial closing wedge or lateral opening wedge techniques. Variable outcomes and complication rates have been reported. A framework for the use of distal femoral varus osteotomy can aid the orthopaedic surgeon in the evaluation and treatment of patients with symptomatic valgus malalignment.
Impact of Morocco-ECOWAS Economic Relations on Economic Growth in Morocco: An Analysis Using the ARDL Model
Authors: Khattabi Hidaya EL , Karim Mohamed
Published: April 2018

Over the last decade, Morocco has undertaken numerous reforms in order to successfully integrate itself into the global economy in general, and Africa in particular, with the aim of diversifying and strengthening its competitive export potential.In fact, the analysis of trade relations between Morocco and ECOWAS reveals an increasing volume of trade, reflecting a continuous dynamization of their commercial relations. A similar trend is observed in foreign direct investment, which has been growing steadily over the last few years, reflecting Morocco’s desire to become a major player in the development of the African continent.The analysis of Morocco’s trade opening and foreign direct investment (FDI) in ECOWAS on Morocco’s economic growth, using ARDL (Autorégressive distribution Lag) modelling, shows that Moroccan foreign direct investment to ECOWAS has a significant impact on its GDP per capita in the short and long term. With regard to bilateral trade between the two partners, no long-term equilibrium relationship could be established due to the still low weight of trade volumes.
Impact of Financial Inclusion on Consumption Expenditure in Kenya
Authors: Mwangi Isaac , Atieno Rosemary
Published: April 2018

This study looked at the impact of financial inclusion on households’ welfare in Kenya based on both the single (transactionary, credit, savings and investment, insurance and pension) and composite measures (portfolio usage) of financial inclusion. The study used repeated household Financial Access datasets for the period 2009 to 2016 to run five autoregressive distribution models to capture the welfare impact. Estimation results established that the impact of financial inclusion on household welfare varies by product with the credit channel taking the lions share. A shift from non-usage (control) to usage (treatment) of financial services (zero one change) among the sampled respondents raises household welfare by 126, 110 and 49 percent with respect to credit, transactionary and insurance products respectively ceteris paribus. Conversely, a counterfactual assessment revealed a 56, 52 and 33 percent drop in welfare from the non-usage of credit, transactionary and insurance products respectively. Portfolio usage of financial services as captured by the index of financial inclusion raises household welfare by 347 percent other factors held constant. Given the positive welfare impact of financial inclusion, the study recommends increase in the range of formal financial products to increase competition in financial markets lowering transaction costs for welfare improvement. Policies targeting welfare improvement through finance should also be aligned to specific financial inclusion transmission channels to be more effective as opposed to blanket proposals.
Examining Risk-Weighted Assets (RWA) Performance after Recent Financial Crisis in Malaysian Banking System
Authors: Mohamad Siti Nor Amira , Basah Mohamad Yazis Ali , Ab Aziz Muhammad Ridhwan
Published: April 2018

Until recently, there has been only muted debate on the stability of RWA and after the recent financial crisis, the new regulatory framework was introduced that will enrich the quality and level of capital ratios for the banking system. However these capital ratios required to be based on specific risk measurement that permits for appropriate comparison as these gives new prominence to the stability of the underlying RWA. The aim of this paper is to examine the RWA performance after recent global financial crisis in Malaysian banking system. The study uses quantitative approach to examine in detail the RWA performance from year 2012 to 2016 using secondary analysis of bank’s annual report.
Monetary Seigniorage in an Emerging Economy: Empirical Evidences
Authors: Chakraborty Lekha
Published: April 2018

It is often emphasised that monetary seigniorage financing of public sector deficits is technically a “free lunch” if the economy has not attained the full employment levels. However, conservative macroeconomic policies in many emerging and developing economies, especially in the last two decades, have moved away from seigniorage financing to debt financing of deficits to give greater autonomy to the central banks. Against this backdrop, the paper analyses the fiscal and monetary policy co-ordination in India by constructing a monetary seigniorage Laffer curve.  If such a curve exists, it is possible to derive a seigniorage-maximizing inflation rate to estimate the optimal level of seigniorage financing of deficits. The illustrative estimates from the Indian data using error correction mechanism models confirm the possibility of a monetary seigniorage Laffer curve.
A Cultural Semiotic Aesthetic Approach for a Virtual Heritage Project
Authors: Voutounos Chrysanthos , Lanitis Andreas ,   Philosophy Documentation Center
Published: April 2018

Continuing from Part A (2016), in which we discuss the semiotic foundation for designing a virtual museum of Byzantine art, Part B presents an applied methodology for the representation of cultural artifacts through virtual technologies and semiotic techniques. We discuss how our semiotic model, case study semiosphere, contributes to design and evaluation research of such unique art-form representation and why the approach contributes as a whole to the field of Virtual Heritage (VH). Theorizing further the design implications integrating the overall approach including the evaluation experiment of three VH applications with the participation of young users and its semiotic analysis, we formulate design guidelines that can be applied also to other types of cultural heritage and art.
Role of Metal Ions, Surfactants and Solvents on Enzymatic Activity of Partial Purified Glucoamylase from Aspergillus niger ER05
Authors: Erum Hanif  , Shah Ali Ul Qader  , Raheela Rahmat Zohra
Published: April 2018

The glucoamylase requirement of different industries should vary in their physiochemical and functional properties, so the investigation of new sources for the novel enzymes is the only solution. The current study describe the production of glucoamylase from Aspergillus niger ER05 in a submerged fermentation. The enzyme then partially purified and then effect of thirteen different metal ions (Cs+, K+, Na+, Ba2+, Ca2+ Co2+, Cu2+ , Hg2+, Mg2+, Mn2+, Ni2+, Zn2+ , Fe3+), surfactant as well as organic solvent on catalytic performance of glucoamylase was studied. A newly isolated Aspergillus niger ER05 is hyper producing strain of glucoamylase. Specific activity for the crude enzyme was found to be 6.87 KU/mg. The crude enzyme was partially purified via fractional ammonium sulphate precipitation. Ammonium sulphate saturation from 40-80% was found suitable to precipitate the enzyme. After dialyzing precipitates, the specific activities were found to be 66.33KU/mg with percent yield of 26.5. The inhibitory influence of all metal studies was interestingly found on glucoamylase activity. The strong inhibition was demonstrated in presence of Hg2+, Ni2+, Zn2+, Cu2+, Fe3+. Only Na+ ions were able to maintain the 101% relative activity at 1mM concentration. The SDS completely inhibits the enzyme activity and in presence of tween-80 and triton X-100 glucoamylase exhibited less than 45% relative activity. Furthermore, formaldehyde, isopropanol, ethanol, methanol, and DMSO stabilized the enzyme activity while chloroform inhibits enzyme activity by 48%.
Construction and Deconstruction of a Homicide Reduction Policy: The Case of Pact for Life in Pernambuco, Brazil
Authors: Ratton José Luiz , Daudelin Jean
Published: April 2018

This paper tries to demonstrate that both the fall in homicides in Pernambuco (from 2007-2013) and the resurgence in them that followed (2014-2017) are fundamentally linked to two explanatory variables, which are in turn connected: the model of governance of public security produced in Pernambuco at the level of state government strategy and the capacity for deterrence produced in the framework of the Criminal Justice System (especially that of state police, who are under the responsibility and “control” of the executive power of the state). This article argues that the construction of this specific model of governance of Public Security and the definition, monitoring and realization of deterrence strategies within the police were crucial to the reduction of the number of homicides in the most violent areas of the state. On the other hand, the dissolution of the capacity for integrated governance of the police, with the consequent dismantling of the deterrence capacity aimed primarily at the reduction of homicides and crimes against life that had been successfully conceived and realized between 2007 and 2013, explains the increase in intentional violent crimes that has been observed since 2014.
Nearest points on toric varieties
Authors: Helmer Martin , Sturmfels Bernd
Published: April 2018

We determine the Euclidean distance degree of a projective toric variety. This extends the formula of Matsui and Takeuchi for the degree of the $A$-discriminant in terms of Euler obstructions. Our primary goal is the development of reliable algorithmic tools for computing the points on a real toric variety that are closest to a given data point.
Stability of rank two Ulrich bundles on projective $K3$ surfaces
Authors: Casnati Gianfranco , Galluzzi Federica
Published: April 2018

Let $F\subseteq \mathbb{P}^{N}$ be a $K3$ surface of degree $2a$, where $a\ge 2$. In this paper we deal with Ulrich bundles on $F$ of rank $2$. We deal with their stability and we construct $K3$ surfaces endowed with families of non-special Ulrich bundles of rank $2$ for each $a\ge 2$.
Mappings preserving approximate orthogonality in Hilbert $C^*$-modules
Authors: Moslehian Mohammad Sal , Zamani Ali
Published: April 2018

We introduce a notion of approximate orthogonality preserving mappings between Hilbert $C^*$-modules. We define the concept of $(\delta , \varepsilon )$-orthogonality preserving mapping and give some sufficient conditions for a linear mapping to be $(\delta , \varepsilon )$-orthogonality preserving. In particular, if $\mathscr {E}$ is a full Hilbert $\mathscr {A}$-module with $\mathbb {K}(\mathscr {H})\subseteq \mathscr {A} \subseteq \mathbb {B}(\mathscr {H})$ and $T, S\colon \mathscr {E}\to \mathscr {E}$ are two linear mappings satisfying $|\langle Sx, Sy\rangle | = \|S\|^2|\langle x, y\rangle |$ for all $x, y\in \mathscr {E}$ and $\|T - S\| \leq \theta \|S\|$, then we show that $T$ is a $(\delta , \varepsilon )$-orthogonality preserving mapping. We also prove whenever $\mathbb {K}(\mathscr {H})\subseteq \mathscr {A} \subseteq \mathbb {B}(\mathscr {H})$ and $T\colon \mathscr {E} \to \mathscr {F}$ is a nonzero $\mathscr {A}$-linear $(\delta , \varepsilon )$-orthogonality preserving mapping between $\mathscr {A}$-modules, then \[ \bigl \|\langle Tx, Ty\rangle - \|T\|^2\langle x, y\rangle \bigr \|\leq \frac {4(\varepsilon - \delta )}{(1 - \delta )(1 + \varepsilon )} \|Tx\|\|Ty\|\qquad (x, y\in \mathscr {E}). \] As a result, we present some characterizations of the orthogonality preserving mappings.
The bounded approximation property of variable Lebesgue spaces and nuclearity
Authors: Delgado Julio , Ruzhansky Michael
Published: April 2018

In this paper we prove the bounded approximation property for variable exponent Lebesgue spaces, study the concept of nuclearity on such spaces and apply it to trace formulae such as the Grothendieck-Lidskii formula. We apply the obtained results to derive criteria for nuclearity and trace formulae for periodic operators on $\mathbb{R}^n$ in terms of global symbols.
$k$-shellable simplicial complexes and graphs
Authors: Rahmati-Asghar Rahim
Published: April 2018

In this paper we show that a $k$-shellable simplicial complex is the expansion of a shellable complex. We prove that the face ring of a pure $k$-shellable simplicial complex satisfies the Stanley conjecture. In this way, by applying an expansion functor to the face ring of a given pure shellable complex, we construct a large class of rings satisfying the Stanley conjecture.Also, by presenting some characterizations of $k$-shellable graphs, we extend some results due to Castrillón-Cruz, Cruz-Estrada and Van Tuyl-Villareal.
Clark measures and a theorem of Ritt
Authors: Chalendar Isabelle , Gorkin Pamela , Partington Jonathan R. , Ross William T.
Published: April 2018

We determine when a finite Blaschke product $B$ can be written, in a non-trivial way, as a composition of two finite Blaschke products (Ritt's problem) in terms of the Clark measure for $B$. Our tools involve the numerical range of compressed shift operators and the geometry of certain polygons circumscribing the numerical range of the relevant operator. As a consequence of our results, we can determine, in terms of Clark measures, when two finite Blaschke products commute.
Topological rigidity of quasitoric manifolds
Authors: Metaftsis Vassilis , Prassidis Stratos
Published: April 2018

Quasitoric manifolds are manifolds that admit an action of the torus that is locally the same as the standard action of $T^n$ on $\mathbb{C}^n$. It is known that the quotients of such actions are nice manifolds with corners. We prove that a class of locally standard manifolds, that contains the quasitoric manifolds, is equivariantly rigid, i.e., that any manifold that is $T^n$-homotopy equivalent to a quasitoric manifold is $T^n$-homeomorphic to it.
Pencils and nets on curves arising from rank $1$ sheaves on K3 surfaces
Authors: Rasmussen Nils Henry
Published: April 2018

Let $S$ be a K3 surface, $C$ a smooth curve on $S$ with $\mathcal{O} _S(C)$ ample, and $A$ a base-point free $g^2_d$ on $C$ of small degree. We use Lazarsfeld-Mukai bundles to prove that $A$ is cut out by the global sections of a rank $1$ torsion-free sheaf $\mathcal{G} $ on $S$. Furthermore, we show that $c_1(\mathcal{G} )$ with one exception is adapted to $\mathcal{O} _S(C)$ and satisfies $\operatorname{Cliff} (c_1(\mathcal{G} )_{|C})\leq \operatorname{Cliff} (A)$, thereby confirming a conjecture posed by Donagi and Morrison. We also show that the same methods can be used to give a simple proof of the conjecture in the $g^1_d$ case.In the final section, we give an example of the mentioned exception where $h^0(C,c_1(\mathcal{G} )_{|C})$ is dependent on the curve $C$ in its linear system, thereby failing to be adapted to $\mathcal{O} _S(C)$.
Community involvement works where enforcement fails: conservation success through community-based management of Amazon river turtle nests
Authors: Norris Darren , Michalski Fernanda , Gibbs James P
Published: April 2018

Law enforcement is widely regarded as a cornerstone to effective natural resource management. Practical guidelines for the optimal use of enforcement measures are lacking particularly in areas protected under sustainable and/or mixed use management regimes and where legal institution are weak. Focusing on the yellow-spotted river turtles (Podocnemis unifilis) along 33 km of river that runs between two sustainable–use reserves in the Brazilian Amazon as an illustrative example, we show that two years of patrols to enforce lawful protection regulations had no effect on nest harvesting. In contrast, during one year when community-based management approaches were enacted harvest levels dropped nearly threefold to a rate (26%) that is likely sufficient for river turtle population recovery. Our findings support previous studies that show how community participation, if appropriately implemented, can facilitate effective natural resource management where law enforcement is limited or ineffective.
Kernelized relative entropy for direct fault detection in industrial rotary kilns
Authors: Hamadouche Anis , Kouadri Abdelmalek , Bensmail Abderazak
Published: April 2018

The objective of this work is to use a 1‐dimensional signal that reflects the dissimilarity between multidimensional probability densities for detection. With the modified Kullback‐Leibler divergence, faults can be directly detected without any normality assumption or joint monitoring of related test statistics in different subspaces such as theT2andSPEin principal component analysis–based methods. To relieve the difficulty associated with asymptotic high‐dimensional density estimates, we have estimated the density ratio rather than the densities themselves. This can be done by approximating the density ratio with kernel basis functions and learn the weights from the available data. The developed algorithm is generic and can be applied to any industrial system as long as process historical data is available. As a case study, we apply this algorithm to a real rotary kiln in operation, which is an integral part of the cement manufacturing plant of Ain El Kebira, Algeria.
Fault detection and identification for a class of continuous piecewise affine systems with unknown subsystems and partitions
Authors: Moustakis Nikolaos , Zhou Bingyu , Le Quang Thuan , Baldi Simone
Published: April 2018

This paper establishes a novel online fault detection and identification strategy for a class of continuous piecewise affine (PWA) systems, namely, bimodal and trimodal PWA systems. The main contributions with respect to the state‐of‐the‐art are the recursive nature of the proposed scheme and the consideration of parametric uncertainties in both partitions and in subsystems parameters. In order to handle this situation, we recast the continuous PWA into its max‐form representation and we exploit the recursive Newton‐Gauss algorithm on a suitable cost function to derive the adaptive laws to estimate online the unknown subsystem parameters, the partitions, and the loss in control authority for the PWA model. The effectiveness of the proposed methodology is verified via simulations applied to the benchmark example of a wheeled mobile robot.
Robust RBF neural network–based backstepping controller for implantable cardiac pacemakers
Authors: Karar Mohamed Esmail
Published: April 2018

Implantable cardiac pacemaker is a standard medical device to treat heart rhythm disorders. In this paper, a new adaptive backstepping controller is developed to enhance the performance of dual‐sensor pacemakers for regulating the heart rate based on radial basis function neural networks. The robust design of adaptive backstepping controller using Lyapunov functions allows to guarantee the stability and performance of the rate‐adaptive pacing system for accurately accomplishing the heart rate regulation at different preset or desired values. The developed control system has been successfully validated using 12 cases of the preset heart rates for 4 patients during 3 body activities, namely, at rest, walking, and jogging. The resulting root mean square error and maximum error are less than 0.9 and 1.7%, respectively. Moreover, the comparative results of this study showed that the performance of developed backstepping controller is superior to other pacemaker controllers in the previous studies. Therefore, it is potentially valid to be applied in dual‐sensor cardiac pacemakers for the clinical use.
Mechanically Robust, Ultraelastic Hierarchical Foam with Tunable Properties via 3D Printing
Authors: Chen Qiyi , Cao Peng‐Fei , Advincula Rigoberto C.
Published: April 2018

A mechanically robust, ultraelastic foam with controlled multiscale architectures and tunable mechanical/conductive performance is fabricated via 3D printing. Hierarchical porosity, including both macro‐ and microscaled pores, are produced by the combination of direct ink writing (DIW), acid etching, and phase inversion. The thixotropic inks in DIW are formulated by a simple one‐pot process to disperse duo nanoparticles (nanoclay and silica nanoparticles) in a polyurethane suspension. The resulting lightweight foam exhibits tailorable mechanical strength, unprecedented elasticity (standing over 1000 compression cycles), and remarkable robustness (rapidly and fully recover after a load more than 20 000 times of its own weight). Surface coating of carbon nanotubes yields a conductive elastic foam that can be used as piezoresistivity sensor with high sensitivity. For the first time, this strategy achieves 3D printing of elastic foam with controlled multilevel 3D structures and mechanical/conductive properties. Moreover, the facile ink preparation method can be utilized to fabricate foams of various materials with desirable performance via 3D printing.
Perovskite‐Initiated Photopolymerization for Singly Dispersed Luminescent Nanocomposites
Authors: Wong Ying‐Chieh , De Andrew Ng Jun , Tan Zhi‐Kuang
Published: April 2018

Metal halide perovskites have demonstrated rich photophysics and remarkable potential in photovoltaic and electroluminescent devices. However, the photoactivity of perovskite semiconductors in chemical processes remains relatively unexplored. Here, a general approach toward the synthesis of luminescent perovskite–polymer nanocomposites is reported, whereby perovskite nanocrystals are used as photoinitiators in the polymerization of vinyl monomers. The white‐light illumination of a perovskite–monomer mixture triggers a free‐radical chain‐growth polymerization process, giving rise to high molecular weight polymers of ≈200 kDa. The in situ growth of polymer chains from the perovskite crystal surface allows the formation of individually dispersed nanocrystal cores within an encapsulating polymer matrix, and leads to a significant threefold enhancement in photoluminescence quantum yield. This photoluminescence enhancement is attributed to the spatial separation of the perovskite nanocrystals and hence the deactivation of energy transfer to dark crystals. The resulting perovskite–polymer nanocomposites exhibit excellent stability against moisture and are shown to be useful as functional downconversion phosphor films for luminescent displays and lighting.
Care Like Kin: Community Based Youth Serving Organizations and the Social Reproduction of Disconnected Youth in Rural America
Authors: Visser M. Anne
Published: April 2018

Increasing economic insecurity faced by older youth in rural America presents a crisis of social reproduction for disconnected youth in these areas. Increasingly community based youth serving organizations (CBYSOs) are recognizing and responding to the social reproduction needs of this particularly vulnerable youth population. Such responses are often hidden from funders, government agencies, and community residents. Yet these institutions play an important substitution function for disconnected youth and provide critical social support and social leverage for this population. Based on case studies of three CBYSOs in the San Joaquin Valley of California, this article explores how and why CBYSOs play a substitution function for disconnected youth in rural communities. It is the argument of this article that the social reproduction work of CBYSOs is undertaken with a ethic of care that may have the capacity to transform the political, social, and economic contexts that face this marginalized youth population.
Cancer mortality update with an exposure response analysis among styrene‐exposed workers in the reinforced plastics boatbuilding industry
Authors: Bertke Stephen J. , Yiin James H. , Daniels Robert D.
Published: April 2018

Background

There is sparse and inconsistent evidence of an association between styrene exposure and cancer.

Methods

This study examines mortality patterns in a previously studied cohort of 5201 workers employed in two Washington boat‐building facilities, extending follow‐up 5 years. Standardized mortality ratios (SMR) were calculated using state rates as referent. Cox regression calculated rate ratios (RR) per year employed in styrene‐exposed exposed jobs.

Results

No excess deaths from lymphohematopoietic cancers (LHCs) were observed (SMR: 0.99, 95%CI: 0.74‐1.30) when compared to the referent population; however, the relative risk increased with duration of employment in internal analyses. Conversely, lung cancer mortality was significantly elevated (SMR: 1.24, 95%CI: 1.08‐1.41), but there was no evidence of a dose‐response relationship.

Conclusion

We found evidence that occupational exposure to styrene was associated with increased LHC risk, while no such association was observed for lung cancer.
Blood pressure and risk of incident Alzheimer's disease dementia by antihypertensive medications and APOE ε4 allele
Authors: Rajan Kumar B. , Barnes Lisa L. , Wilson Robert S. , Weuve Jennifer , McAninch Elizabeth A. , Evans Denis A.
Published: April 2018

Objective

To examine the association of blood pressure (BP) with incident Alzheimer's disease (AD) dementia.

Methods

This work is based on a longitudinal, cohort study of 18 years, the Chicago Health and Aging Project (CHAP) performed in 2,137 participants (55% black) with systolic BP measured around 8.1 years before incident AD dementia.

Results

The association of BP with risk of AD dementia was U‐shaped, with the lowest risks of AD dementia near the center of the systolic BP (SBP) and diastolic BP (DBP) distributions, and modestly elevated risk at lower BPs, and greater risk at higher BPs. The degree of U‐shape and the range of lowest risk (threshold ranges) varied with antihypertensive medication use and presence of the APOE ε4 allele. The U‐shape was most prominent for the subgroup not taking antihypertensive medications and having an APOE ε4 allele. At higher BPs, those having the APOE ε4 allele and not receiving antihypertensive medication were at greater risk of AD dementia than other groups: The risk of incident AD dementia increased by 100% (relative risk [RR] = 2.00; 95% confidence interval [CI] = 1.70, 2.31) for every 10 mm Hg increase in SBP above 140 mm Hg. For DBP, the risk of incident of AD dementia increased by 57% (RR = 1.57; 95% CI = 1.33, 1.86) for every 5 mm Hg increase in DBP above 76 mm Hg.

Interpretation

The BP risk of AD dementia association is U‐shaped, with elevated risk at lower and higher BPs. People having the APOE ε4 allele and not receiving antihypertensive medication with higher BPs have notably elevated risk of AD dementia. Ann Neurol 2018;83:935–944
Core Electron Topologies in Chemical Compounds: Case Study of Carbon versus Silicon
Authors: Yoshida Daisuke , Raebiger Hannes , Shudo Ken‐ichi , Ohno Koichi
Published: April 2018

The similarities and differences between carbon and silicon have attracted the curiosity of chemists for centuries. Similarities and analogies can be found in their saturated compounds, but carbon exhibits a cornucopia of unsaturated compounds that silicon (and most other elements) cannot replicate. While this qualitative difference is empirically well known, quantum chemistry has previously only described quantitative differences related to orbital overlap, steric effects, or orbital energies. We study C2 and Si2 and their hydrides X2H2n (X=C, Si; n=1, 2, 3) by first‐principles quantum chemical calculation, and find a qualitative difference in the topologies of the core electrons: carbon has the propensity to alter its core electron topology when forming unsaturated compounds, and silicon has not. We draw a connection between the core electron topologies and ionization energies, and identify other elements we expect to have similarly flexible core topologies as carbon.
Reconstruction of Supported Metal Nanoparticles in Reaction Conditions
Authors: Duan Manyi , Yu Jian , Meng Jun , Zhu Beien , Wang Yong , Gao Yi
Published: April 2018

Metal nanoparticles (NPs) dispersed on a high‐surface‐area support are normally used as heterogeneous catalysts. Recent in situ experiments have shown that structure reconstruction of the NP occurs in real catalysis. However, the role played by supports in these processes is still unclear. Supports can be very important in real catalysis because of the new active sites at the perimeter interface between nanoparticles and supports. Herein, using a developed multiscale model coupled with in situ spherical aberration‐corrected (Cs‐corrected) TEM experiments, we show that the interaction between the support and the gas environment greatly changes the contact surface area between the metal and support, which further leads to the critical change in the perimeter interface. The dynamic changes of the interface in reactive environments can thus be predicted and be included in the rational design of supported metal nanocatalysts. In particular, our multiscale model shows quantitative consistency with experimental observations. This work offers possibilities for obtaining atomic‐scale structures and insights beyond the experimental limits.
Facile, Quick, and Gram‐Scale Synthesis of Ultralong‐Lifetime Room‐Temperature‐Phosphorescent Carbon Dots by Microwave Irradiation
Authors: Jiang Kai , Wang Yuhui , Gao Xiaolu , Cai Congzhong , Lin Hengwei
Published: April 2018

Long‐lifetime room‐temperature phosphorescence (RTP) materials are important for many applications, but they are highly challenging materials owing to the spin‐forbidden nature of triplet exciton transitions. Herein, a facile, quick and gram‐scale method for the preparation of ultralong RTP (URTP) carbon dots (CDs) was developed via microwave‐assisted heating of ethanolamine and phosphoric acid aqueous solution. The CDs exhibit the longest RTP lifetime, 1.46 s (more than 10 s to naked eye) for CDs‐based materials to date. The doping of N and P elements is critical for the URTP which is considered to be favored by a n→π* transition facilitating intersystem crossing (ISC) for effectively populating triplet excitons. In addition, possibilities of formation of hydrogen bonds in the interior of the CDs may also play a significant role in producing RTP. Potential applications of the URTP CDs in the fields of anti‐counterfeiting and information protection are proposed and demonstrated.
Modeling and simulation of particle dispersion in dense particle‐laden flow
Authors: Li Guohui , Li Xiangli
Published: April 2018

Traditional drag force coefficient with regard to modeling gas–particle flows is generally established on the semiempirical or full empirical measurement data with isotropic hypothesis resulting in neglection of true particle dispersions, especially for anisotropic characteristics. A developed drag force coefficient to fully consider the anisotropics was applied to model and simulate dense particle‐laden flows. Coupled with a unified second‐order moment, 2‐fluid turbulent model consisting of a set of fluctuation velocity Reynolds transport equations was employed for predicting dense particle‐laden flows in pseudo‐2D horizontal chamber. Simulated results showed that they are in good agreement with measurement data. Particle Reynolds stresses have been redistributed by the momentum transfer interaction term between gas and particle phases, the turbulent diffusion term, and the particle collision term. Compared with traditional Wen's model, horizontal and vertical root‐mean‐square of particle velocities exhibited much more flatter and wider distribution behaviors. Due to limitation of two‐dimensional model and wall conditions, errors near wall regions should be improved in future work.
Semiaromatic polyamide poly(hexamethylene terephthalamide)‐co‐polycaprolactam: Thermal and flame‐retardant properties
Authors: Peng Wei‐Ming , Tong Xin , Zhang Mei‐Lin , Wang Xiao‐Jun , Zhang Gang , Long Sheng‐Ru , Yang Jie
Published: April 2018

The poly(hexamethylene terephthalamide)‐co‐polycaprolactam (PA6T/6; 50:50) copolymer was synthesized with a reactive extrusion method and subsequently mixed with a certain content of glass fibers (GFs) and different ratios of flame‐retardant aluminum diethyl phosphinate (AlPi) to fabricate a series of composites. These resulting composites were found to have excellent mechanical (tensile strength = 119–154 MPa) and thermal properties (heat‐deflection temperature = 263–293 °C). It is particularly worth mentioning that the value of the limiting oxygen index reached 29.5% and a UL‐94 V‐0 rating (1.6 mm) was achieved with the addition of 20 portions of AlPi. Also, the values of the peak heat‐release rate and total heat release in cone calorimetry were found to decrease with the addition of the flame‐retardant AlPi, which acted mainly as a flame inhibitor in the gas phase. Through visual observation, scanning electron microscopy after cone calorimetry testing, and thermogravimetric analysis, the condensed‐phase flame‐retardant mechanism of the PA6T/6–GF–AlPi system was confirmed to have a synergetic role. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46451.
TFC reverse osmosis polyamide membranes—Effect of increasing sulfonic group concentration on water flux and salt rejection performance
Authors: Yam‐Cervantes Marcial , Pérez‐Padilla Yamile , Aguilar‐Vega Manuel
Published: April 2018

Thin film composite (TFC) membranes for reverse osmosis were prepared with a polyamide top layer with an increasing concentration of sulfonic groups obtained with mixtures of m‐phenylenediamine (MPD), and the sulfonated diamine, 4‐diaminobenzensulfonic acid (DABS) crosslinked with trimesoyl chloride via interfacial polymerization. The presence of sulfonic groups in the top layer diminishes the roughness of the surface of the membrane as observed by scanning electron microscopy and atomic force microscopy. It was also found that the best curing temperature for stabilization of the top polyamide layer in the TFC membrane was 90 °C. Increased hydrophilicity with an increasing concentration of DABS in the top layer of the membrane was confirmed by contact angle measurements. The results show that concentrations above 5 wt % DABS were detrimental for the membrane flux and salt rejection, R(%). The incorporation of sulfonic groups up to 5 wt % DABS improves the flux and R(%) as compared to a TFC membrane without ionic groups. Constant salt rejection was observed in the TFC membrane with 5 wt % DABS which at least maintain a nearly constant water flux after three cycles and improve R(%) after repeated testing of the same membrane in a RO high pressure cell. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46500.
Synergistic effect of kaolinite/halloysite on the flammability and thermostability of polypropylene
Authors: Sun Wenxiang , Tang Wufei , Gu Xiaoyu , Zhang Sheng , Sun Jun , Li Hongfei , Liu Xiaodong
Published: April 2018

Kaolinite (Kaol) and halloysite nanotubes (HNT) are both aluminosilicate clays with similar chemical formulation and different microshapes. In this article, nanotubular HNT and nanoplate Kaol together were introduced into polypropylene (PP) containing intumescent flame retardant (IFR). The flammability of the PP composites was characterized by limiting oxygen index (LOI), vertical burning (UL‐94), and cone calorimeter tests (CCT). The results showed that for the composite with 75 wt % PP and 25 wt % IFR, its LOI was 31.0% and it obtained a UL‐94 grade of V‐2. For the composite of 75 wt % PP, 23.5 wt % IFR, and 1.5 wt % (Kaol/HNT = 9/1), its LOI increased to 36.9 and it obtained a UL‐94 grade of V‐0; at the same time, its peak heat release rate value in CCT decreased by 82.2% compared to neat PP. The thermostability analysis indicated that the mixture of Kaol/HNT could improve the thermostability and final char yield. The char residues were comprehensively analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy. The results illustrated that the Kaol/HNT combination was beneficial to forming a crosslinked network and promoting formation of a compact char with higher strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46507.
Methodologies for “Wiring” Redox Proteins/Enzymes to Electrode Surfaces
Authors: Yates Nicholas D. J. , Fascione Martin A. , Parkin Alison
Published: April 2018

The immobilization of redox proteins or enzymes onto conductive surfaces has application in the analysis of biological processes, the fabrication of biosensors, and in the development of green technologies and biochemical synthetic approaches. This review evaluates the methods through which redox proteins can be attached to electrode surfaces in a “wired” configuration, that is, one that facilitates direct electron transfer. The feasibility of simple electroactive adsorption onto a range of electrode surfaces is illustrated, with a highlight on the recent advances that have been achieved in biotechnological device construction using carbon materials and metal oxides. The covalent crosslinking strategies commonly used for the modification and biofunctionalization of electrode surfaces are also evaluated. Recent innovations in harnessing chemical biology methods for electrically wiring redox biology to surfaces are emphasized.
Induction of immunity following vaccination with a chemically attenuated malaria vaccine correlates with persistent antigenic stimulation
Authors: Reiman Jennifer M , Kumar Sanjai , Rodriguez Ingrid B , Gnidehou Sedami , Ito Koichi , Stanisic Danielle I , Lee Moses , McPhun Virginia , Majam Victoria , Willemsen Nicole M , Batzloff Michael R , Raja Amber I , Dooley Brad , Hoffman Stephen L , Yanow Stephanie K , Good Michael F
Published: April 2018

Objectives

Blood stage malaria parasites attenuated with seco‐cyclopropyl pyrrolo indole (CPI) analogues induce robust immunity in mice to homologous and heterologous malaria parasites and are being considered for the development of a human vaccine. However, it is not understood how attenuated parasites induce immunity. We showed that following vaccination, parasite DNA persisted in blood for several months, raising the possibility that ongoing immune stimulation may be critical. However, parasites were not seen microscopically beyond 24 h postvaccination. We aimed to provide a mechanistic understanding of immune induction.

Methods

Mice were vaccinated with chemically attenuated Plasmodium chabaudi parasites. PCR and adoptive transfer studies were used to determine the presence of parasites and antigen in vivo. In other experiments, Plasmodium falciparum parasitised red blood cells were attenuated in vitro and RNA and antigen expression studied.

Results

We show that blood transferred from vaccinated mice into naïve mice activates T cells and induces complete protective immunity in the recipient mice strongly suggesting that there is persistence of parasite antigen postvaccination. This is supported by the presence of parasite RNA in vaccinated mice and both RNA and antigen expression in P. falciparum cultures treated with CPI drugs in vitro. In addition, drugs that block parasite growth also prevent the induction of immunity in vaccinated mice, indicating that some growth of attenuated parasites is required for immune induction.

Conclusions

Attenuated parasites persist at submicroscopic levels in the blood of mice postvaccination with the ability to activate T cells and induce ongoing protective immune responses.
Multi‐impurity divertor simulation using a Monte Carlo kinetic impurity transport model
Authors: Hoshino K. , Homma Y. , Tokunaga S. , Shimizu K.
Published: April 2018

The effects of multi‐impurity transport are important for the divertor plasma performance. To simulate the radiative divertor plasma precisely, we have extended the integrated divertor code, SONIC, to the simulation with multi‐impurity species. For SONIC extension, a new integrated modelling framework using the multiple‐program multiple‐data approach and message passing interface data exchange has been developed. In the framework, two impurities and more can be treated simultaneously with several Monte Carlo kinetic impurity codes. The extended SONIC code has been applied to analyse the JT‐60SA radiative divertor plasma. The SONIC simulation including multi‐impurity transport demonstrates that the radiative divertor plasma scenario compatible with the steady‐state high‐β plasma can be achieved.