bluuebunny/crossref_metadata_2025 huggingface dataset:
Combating Leishmaniasis through Awareness Campaigning: A Mathematical Study on Media Efficiency
Authors: Biswas Dibyendu , Datta Abhirup , Roy Priti Kumar
Published: March 2019

Leishmaniasis is a complex vector-borne disease that is originated by protozoa of the genus Leishmania. The disease is transmitted to human or animals through bites of infected female Phlebotominae sand-fly. Awareness campaign plays a significant role to restrict the spreading of disease cutaneous leishmaniasis. Here, we have considered a mathematical model of cutaneous leishmaniasis (CL) consisting susceptible and infected population of human and vector. Increase in growth of aware population impulsively leading to reduction of incompetence for environmental factors. Our analytical and numerical results reveal that circulating of the campaigning periodically minimizes the disease prevalence. The efficiency of the awareness programme contributes a better regime on the system moving towards healthy and hygienic environment.
Diffusion of Innovations: Patenting or Standardization
Authors: Aronov Iosif , Zazhigalkin Aleksandr
Published: March 2019

In this paper, the authors proposed provisions under which the standards are more preferable than patents. They are defined in duopoly model of Standard - Patent. The article shows that the observed criterion (criteria) of efficiency standards in comparison with patents is a small scatter of royalties specific to the assessment of the cost of the license. Based on this criterion, sectors of the economy in which the standard can be more effective than patent for user were identified.
Stochastic Formulation of Fault Severity Based Multi Release SRGM Using the Effect of Logistic Learning
Authors: Singh Jagvinder , Bhati Suneeta , Prasanan A. R. , Vayas Ashok
Published: March 2019

In today’s environment, software reliability is one of the major concerns for Software firms. Many Software Reliability Growth Model (SRGM) has been developed and many are under process. In order to meet the requirements of consumer and to excel in competitive environment, companies are coming up with multiple add –ons. We design the model as stochastic with continuous state space because of large software system, the count of failures observed is huge and so, the variation in count of errors detected/ removed in each debugging is petite compared to original error content at the beginning of testing. This study is an add on to the software reliability literature where we have developed multi release SRGM’s based on available concept of depending on previous releases. The errors have been categorically divided upon the severity of their removal as one stage, two stage, three stage fault removal process is applied in an environment of irregular fluctuations.
SIL Implementation on Safety Functions in Mass Transit System
Authors: Li James
Published: March 2019

The concept of Safety Integrity Level (SIL) has been developed within different systems of standards (IEC 61508, EN50129 and DEF-STAN 00-56). These standards are applied in different areas: control technology (IEC 61508), railway technology (EN50128 and EN 50129), and defense technology (DEF-STAN-00-56). Nowadays, a lot of the mass transit turnkey projects around the world demand the contractors to follow CENELEC standards and SIL concept for the safety function implementation. Although the concept of SIL is mentioned in these standards, the interpretation of the concept of SIL in these standards is not consistent and unequivocal. This paper is written to elaborate the anomalies of SIL interpretation among these various standards in order for safety engineers to obtain a more detailed view on the concept of SIL over these standards.
An Improved CPU Time in Triangle Splitting Method for Solving a Biobjective Mixed Integer Program
Authors: Al-Hasani Ali , Al-Rabeeah Al-Rabeeah , Kumar Santosh , Eberhard Andrew
Published: March 2019

In this paper, an existing algorithm known as Triangle Splitting Method (TSM) for the Bi-Objective Mixed Integer Program (BOMIP) has been modified, which has been named “An Improved Triangle Splitting Method (ITSM)”. The TSM solves many unnecessary single objectives Mixed Integer Programs (MIP) to split each triangle with two rectangles, and second, it doesn’t find the all efficient frontiers. The proposed ITSM has resulted in redaction of CPU time by solving one MIP at each triangle and finds more number of nondominated frontiers compared to the TSM. The proposed modification has been tested in many instances.
A General Class of Tests for Testing Homogeneity of Location Parameters against Umbrella Alternatives
Authors: Goyal Manish , Kumar Narinder
Published: March 2019

In this paper, a general class of non-parametric tests for testing homogeneity of location parameter against umbrella alternatives is proposed. Testing for umbrella alternatives has many applications in the field of biology, medicine, botany, dose level testing, engineering, economics, psychology, zoology. As an example, the effectiveness of a drug is likely to increase with increase of dose up to a certain level and then its effect begins to decrease. The proposed test is based on linear combination of two-sample U-statistics. The null distribution of the test statistics is developed. We compare the test with some other competing tests in terms of Pitman asymptotic relative efficiency. To see execution of the test, a numerical example is provided. Simulation study is carried out to assess the power of proposed class of tests.
Eosinophilic Gastroenteritis with Appendix Involvement: Role of Intestinal Ultrasound
Authors: Bertè Roberto , Soru Pietro , Vecchi Maurizio , Fraquelli Mirella
Published: March 2019

Eosinophilic gastroenteritis (EG) is a rare condition characterized by patchy eosinophilic inflammation of one or more layers of the gastrointestinal tract with no secondary causes of eosinophilia. EG is a treatable disease and, generally, patients show a positive response to steroid therapy. Sometimes the disease can present as acute abdomen, and appendicular involvement has seldom been described in the course of EG. In our case report we aimed to emphasize how useful gastrointestinal ultrasound is as a valuable tool for diagnosing and monitoring intestinal involvement during EG, avoiding invasive tests and unnecessary surgery.
Virtual Inertia and Mechanical Power-Based Control Strategy to Provide Stable Grid Operation under High Renewables Penetration
Authors: Mehrasa Majid , Pouresmaeil Edris , Soltani Hamid , Blaabjerg Frede , Calado Maria R. A. , Catalão João P. S.
Published: March 2019

This paper presents a virtual inertia and mechanical power-based control strategy to provide a stable operation of the power grid under high penetration of renewable energy sources (RESs). The proposed control technique is based on a new active and reactive power-based dynamic model with the permanent magnet synchronous generator (PMSG) swing equation, in which all PMSG features i.e., inertia and mechanical power are embedded within the controller as the main contribution of this paper. To present an accurate analysis of the virtual PMSG-based parameters, the desired zero dynamics of the grid angular frequency are considered to evaluate the effects of virtual mechanical power (VMP) on the active and reactive power sharing, as well as the investigation of virtual inertia variations for the grid angular frequency responses. Moreover, by considering various active power errors and virtual inertia, the impacts of active power error on reactive power in the proposed control technique, are precisely assessed. Simulation results are employed in Matlab/Simulink software to verify the stabilizing abilities of the proposed control technique.
Correlation between Spatial-Temporal Variation in Landscape Patterns and Surface Water Quality: A Case Study in the Yi River Watershed, China
Authors: Bian Ziqi , Liu Lyuyi , Ding Shengyan
Published: March 2019

The evidence for a correlation between landscape patterns and surface water quality is still weak. We chose the Yi River watershed in China as a study area. We selected and determined the chemical oxygen demand, ammonia nitrogen, total phosphorus, dissolved oxygen, and electric conductivity to represent the surface water quality. We analyzed the spatial distribution of the surface water quality. Buffer zones with five different radii were built around each sampling site to analyze landscape patterns on different scales. A correlation analysis was completed to examine the influencing rules and the response mechanisms between landscape patterns and surface water quality indicators. The results show that: (1) Different landscape composition types impact the surface water quality differently and increasing the area of forest land can effectively reduce non-point source pollution, (2) an increase in urban area may threaten the surface water quality, and (3) landscape compositional change has a greater influence on surface water quality compared to landscape configurational change. This study provides a scientific foundation for the spatial development of watersheds and outlines a strategy for improving the sustainability of surface water quality and the surrounding environment.
An Algorithm for Scene Text Detection Using Multibox and Semantic Segmentation
Authors: Qin Hongbo , Zhang Haodi , Wang Hai , Yan Yujin , Zhang Min , Zhao Wei
Published: March 2019

An outside mutual correction (OMC) algorithm for natural scene text detection using multibox and semantic segmentation was developed. In the OMC algorithm, semantic segmentation and multibox were processed in parallel, and the text detection results were mutually corrected. The mutual correction process was divided into two steps: (1) The semantic segmentation results were employed in the bounding box enhancement module (BEM) to correct the multibox results. (2) The semantic bounding box module (SBM) was used to optimize the adhesion text boundary of the semantic segmentation results. Non-maximum suppression (NMS) was adopted to merge the SBM and BEM results. Our algorithm was evaluated on the ICDAR2013 and SVT datasets. The experimental results show that the developed algorithm had a maximum increase of 13.62% in the F-measure score and the highest F-measure score was 81.38%.
Cellular and Immunohistochemical Changes in Anaphylactic Shock Induced in the Ovalbumin-Sensitized Wistar Rat Model
Authors: Al-Salam Suhail , Aburawi Elhadi H. , Al-Hammadi Suleiman , Dhanasekaran Sekhar , Shafiuallah Mohamed , Yasin Javed , Sudhadevi Manjusha , Awwad Aktham , Alper Seth L. , Kazzam Elsadig E. , Bellou Abdelouahab
Published: March 2019

Anaphylactic shock (AS) is a life-threatening, multisystem disorder arising from sudden release of mast cell- and basophil-derived mediators into the circulation. In this study, we have used a Wistar rat model to investigate AS-associated histopathologic changes in various organs. Rats were sensitized with ovalbumin (1 mg s.c), and AS was induced by intravenous injection of ovalbumin (1 mg). Experimental groups included nonallergic rats (n = 6) and allergic rats (n = 6). Heart rate and blood pressure were monitored during one hour. Organs were harvested at the end of the experiment and prepared for histologic and immunohistochemical studies. Lung, small bowel mucosa and spleen were found to undergo heavy infiltration by mast cells and eosinophils, with less prominent mast cell infiltration of cardiac tissue. The mast cells in lung, small bowel and spleen exhibited increased expression of tryptase, c-kit and induced nitric oxide synthase (iNOS). Increased expression of endothelial nitric oxide synthase (eNOS) by vascular endothelial cells was noted principally in lung, heart and small bowel wall. The Wistar rat model of AS exhibited accumulation of mast cells and eosinophils in the lung, small bowel, and spleen to a greater extent than in the heart. We conclude that lung and gut are principal inflammatory targets in AS, and likely contribute to the severe hypotension of AS. Targeting nitric oxide (NO) production may help reduce AS mortality.
ADRB2-Targeting Therapies for Prostate Cancer
Authors: Kulik George
Published: March 2019

There is accumulating evidence that β-2 adrenergic receptor (ADRB2) signaling contributes to the progression and therapy resistance of prostate cancer, whereas availability of clinically tested β-blocker propranolol makes this pathway especially attractive as potential therapeutic target. Yet even in tumors with active ADRB2 signaling propranolol may be ineffective. Inhibition of apoptosis is one of the major mechanisms by which activation of ADRB2 contributes to prostate cancer pathophysiology. The signaling network that controls apoptosis in prostate tumors is highly redundant, with several signaling pathways targeting a few critical apoptosis regulatory molecules. Therefore, a comprehensive analysis of ADRB2 signaling in the context of other signaling mechanisms is necessary to identify patients who will benefit from propranolol therapy. This review discusses how information on the antiapoptotic mechanisms activated by ADRB2 can guide clinical trials of ADRB2 antagonist propranolol as potential life-extending therapy for prostate cancer. To select patients for clinical trials of propranolol three classes of biomarkers are proposed. First, biomarkers of ADRB2/cAMP-dependent protein kinase (PKA) pathway activation; second, biomarkers that inform about activation of other signaling pathways unrelated to ADRB2; third, apoptosis regulatory molecules controlled by ADRB2 signaling and other survival signaling pathways.
Light Modulation of Human Clocks, Wake, and Sleep
Authors: Prayag Abhishek S. , Münch Mirjam , Aeschbach Daniel , Chellappa Sarah L. , Gronfier Claude
Published: March 2019

Light, through its non-imaging forming effects, plays a dominant role on a myriad of physiological functions, including the human sleep–wake cycle. The non-image forming effects of light heavily rely on specific properties such as intensity, duration, timing, pattern, and wavelengths. Here, we address how specific properties of light influence sleep and wakefulness in humans through acute effects, e.g., on alertness, and/or effects on the circadian timing system. Of critical relevance, we discuss how different characteristics of light exposure across the 24-h day can lead to changes in sleep–wake timing, sleep propensity, sleep architecture, and sleep and wake electroencephalogram (EEG) power spectra. Ultimately, knowledge on how light affects sleep and wakefulness can improve light settings at home and at the workplace to improve health and well-being and optimize treatments of chronobiological disorders.
Qualitative Analysis of Satisfying and Dissatisfying Factors in a University–Industry Cooperation Programme
Authors: Luo Jian Ming , Lam Chi Fung
Published: March 2019

Using qualitative semistructured interviews, this study aims to analyse the satisfying and dissatisfying factors in a university–industry cooperation programme. Work experience, monetary benefit, HR policies, language and time are important factors determining the satisfaction and dissatisfaction of students towards a university–industry cooperation programme. Results help in evaluating and identifying the sustainability of a programme. Marketing practitioners can consider the results in designing corresponding marketing strategies, and HR managers and programme coordinators can formulate guidelines for future improvements of related programmes.
Network-Oriented Real-Time Embedded System Considering Synchronous Joint Space Motion for an Omnidirectional Mobile Robot
Authors: Delgado Raimarius , Choi Byoung Wook
Published: March 2019

This paper proposes a real-time embedded system for joint space control of omnidirectional mobile robots. Actuators driving an omnidirectional mobile robot are connected in a line topology which requires synchronization to move simultaneously in translation and rotation. We employ EtherCAT, a real-time Ethernet network, to control servo controllers for the mobile robot. The first part of this study focuses on the design of a low-cost embedded system utilizing an open-source EtherCAT master. Although satisfying real-time constraints is critical, a desired trajectory on the center of the mobile robot should be decomposed into the joint space to drive the servo controllers. For the center of the robot, a convolution-based path planner and a corresponding joint space control algorithm are presented considering its physical limits. To avoid obstacles that introduce geometric constraints on the curved path, a trajectory generation algorithm considering high curvature turning points is adapted for an omnidirectional mobile robot. Tracking a high curvature path increases mathematical complexity, which requires precise synchronization between the actuators of the mobile robot. An improvement of the distributed clock—the synchronization mechanism of EtherCAT for slaves—is presented and applied to the joint controllers of the mobile robot. The local time of the EtherCAT master is dynamically adjusted according to the drift of the reference slave, which minimizes the synchronization error between each joint. Experiments are conducted on our own developed four-wheeled omnidirectional mobile robot. The experiment results confirm that the proposed system is very effective in real-time control applications for precise motion control of the robot even for tracking high curvature paths.
Design of Neural Network Quantizers for Networked Control Systems
Authors: Rodriguez Ramirez Juan Esteban , Minami Yuki
Published: March 2019

Nowadays, networked control systems (NCSs) are being widely implemented in many applications. However, several problems negatively affect and compromise the design of practical NCSs. One of them is the performance degradation of the system due to quantization. This paper aims to develop dynamic quantizers for NCSs and their design methods that alleviate the effects of the quantization problem. In this paper, we propose a type of dynamic quantizers implemented with neural networks and memories, which can be tuned by a time series data of the plant inputs and outputs. Since the proposed quantizer can be designed without the model information of the system, the quantizer could be applied to any system with uncertainty or nonlinearity. This paper gives two types of quantizers, and they differ from each other in the neural networks structure. The effectiveness of these quantizers and their design method are verified using numerical examples. Besides, their performances are compared among each other using statistical analysis tools.
Combining Distributed Consensus with Robust H∞-Control for Satellite Formation Flying
Authors: Scharnagl Julian , Kempf Florian , Schilling Klaus
Published: March 2019

Control methods that guarantee stability in the presence of uncertainties are mandatory in space applications. Further, distributed control approaches are beneficial in terms of scalability and to achieve common goals, especially in multi-agent setups like formation control. This paper presents a combination of robust H ∞ control and distributed control using the consensus approach by deriving a distributed consensus-based generalized plant description that can be used in H ∞ synthesis. Special focus was set towards space applications, namely satellite formation flying. The presented results show the applicability of the developed distributed robust control method to a simple, though realistic space scenario, namely a spaceborne distributed telescope. By using this approach, an arbitrary number of satellites/agents can be controlled towards an arbitrary formation geometry. Because of the combination with robust H ∞ control, the presented method satisfies the high stability and robustness demands as found e.g., in space applications.
A Passivity-Based Strategy for Manual Corrections in Human-Robot Coaching
Authors: Talignani Landi Chiara , Ferraguti Federica , Fantuzzi Cesare , Secchi Cristian
Published: March 2019

In recent years, new programming techniques have been developed in the human-robot collaboration (HRC) field. For example, walk-through programming allows to program the robot in an easy and intuitive way. In this context, a modification of a portion of the trajectory usually requires the teaching of the path from the beginning. In this paper we propose a passivity-based method to locally change a trajectory based on a manual human correction. At the beginning the robot follows the nominal trajectory, encoded through the Dynamical Movement Primitives, by setting high control gains. When the human grasps the end-effector, the robot is made compliant and he/she can drive it along the correction. The correction is optimally joined to the nominal trajectory, resuming the path tracking. In order to avoid unstable behaviors, the variation of the control gains is performed exploiting energy tanks, preserving the passivity of the interaction. Finally, the correction is spatially fixed so that a variation in the boundary conditions (e.g., the initial/final points) does not affect the modification.
An Orphan CpG Island Drives Expression of a let-7 miRNA Precursor with an Important Role in Mouse Development
Authors: Koerner Martha V. , Chhatbar Kashyap , Webb Shaun , Cholewa-Waclaw Justyna , Selfridge Jim , De Sousa Dina , Skarnes Bill , Rosen Barry , Thomas Mark , Bottomley Joanna , Ramirez-Solis Ramiro , Lelliott Christopher , Adams David J. , Bird Adrian
Published: March 2019

Most human genes are associated with promoters embedded in non-methylated, G + C-rich CpG islands (CGIs). Not all CGIs are found at annotated promoters, however, raising the possibility that many serve as promoters for transcripts that do not code for proteins. To test this hypothesis, we searched for novel transcripts in embryonic stem cells (ESCs) that originate within orphan CGIs. Among several candidates, we detected a transcript that included three members of the let-7 micro-RNA family: Let-7a-1, let-7f-1, and let-7d. Deletion of the CGI prevented expression of the precursor RNA and depleted the included miRNAs. Mice homozygous for this mutation were sub-viable and showed growth and other defects. The results suggest that despite the identity of their seed sequences, members of the let-7 miRNA family exert distinct functions that cannot be complemented by other members.
Large-Scale Station-Level Crowd Flow Forecast with ST-Unet
Authors: Zhou Yirong , Chen Hao , Li Jun , Wu Ye , Wu Jiangjiang , Chen Luo
Published: March 2019

High crowd mobility is a characteristic of transportation hubs such as metro/bus/bike stations in cities worldwide. Forecasting the crowd flow for such places, known as station-level crowd flow forecast (SLCFF) in this paper, would have many benefits, for example traffic management and public safety. Concretely, SLCFF predicts the number of people that will arrive at or depart from stations in a given period. However, one challenge is that the crowd flows across hundreds of stations irregularly scattered throughout a city are affected by complicated spatio-temporal events. Additionally, some external factors such as weather conditions or holidays may change the crowd flow tremendously. In this paper, a spatio-temporal U-shape network model (ST-Unet) for SLCFF is proposed. It is a neural network-based multi-output regression model, handling hundreds of target variables, i.e., all stations’ in and out flows. ST-Unet emphasizes stations’ spatial dependence by integrating the crowd flow information from neighboring stations and the cluster it belongs to after hierarchical clustering. It learns the temporal dependence by modeling the temporal closeness, period, and trend of crowd flows. With proper modifications on the network structure, ST-Unet is easily trained and has reliable convergency. Experiments on four real-world datasets were carried out to verify the proposed method’s performance and the results show that ST-Unet outperforms seven baselines in terms of SLCFF.
Sub-ppb Level Detection of BTEX Gaseous Mixtures with a Compact Prototype GC Equipped with a Preconcentration Unit
Authors: Lara-lbeas Irene , Rodríguez-Cuevas Alberto , Andrikopoulou Christina , Person Vincent , Baldas Lucien , Colin Stéphane , Le Calvé Stéphane
Published: March 2019

In this work, a compact gas chromatograph prototype for near real-time benzene, toluene, ethylbenzene and xylenes (BTEX) detection at sub-ppb levels has been developed. The system is composed of an aluminium preconcentrator (PC) filled with Basolite C300, a 20 m long Rxi-624 capillary column and a photoionization detector. The performance of the device has been evaluated in terms of adsorption capacity, linearity and sensitivity. Initially, PC breakthrough time for an equimolar 1 ppm BTEX mixture has been determined showing a remarkable capacity of the adsorbent to quantitatively trap BTEX even at high concentrations. Then, a highly linear relationship between sample volume and peak area has been obtained for all compounds by injecting 100-ppb samples with volumes ranging from 5–80 mL. Linear plots were also observed when calibration was conducted in the range 0–100 ppb using a 20 mL sampling volume implying a total analysis time of 19 min. Corresponding detection limits of 0.20, 0.26, 0.49, 0.80 and 1.70 ppb have been determined for benzene, toluene, ethylbenzene, m/p-xylenes and o-xylene, respectively. These experimental results highlight the potential applications of our device to monitor indoor or outdoor air quality.
Conformation and Dynamics of Long-Chain End-Tethered Polymers in Microchannels
Authors: Roy Tamal , Szuttor Kai , Smiatek Jens , Holm Christian , Hardt Steffen
Published: March 2019

Polyelectrolytes constitute an important group of materials, used for such different purposes as the stabilization of emulsions and suspensions or oil recovery. They are also studied and utilized in the field of microfluidics. With respect to the latter, a part of the interest in polyelectrolytes inside microchannels stems from genetic analysis, considering that deoxyribonucleic acid (DNA) molecules are polyelectrolytes. This review summarizes the single-molecule experimental and molecular dynamics simulation-based studies of end-tethered polyelectrolytes, especially addressing their relaxation dynamics and deformation characteristics under various external forces in micro-confined environments. In most of these studies, DNA is considered as a model polyelectrolyte. Apart from summarizing the results obtained in that area, the most important experimental and simulation techniques are explained.
Preparation and Characterization of Transparent Polyimide–Silica Composite Films Using Polyimide with Carboxylic Acid Groups
Authors: Moon Kwan Ho , Chae Boknam , Kim Ki Seung , Lee Seung Woo , Jung Young Mee
Published: March 2019

Polyimide (PI) composite films with thicknesses of approximately 100 µm were prepared via a sol–gel reaction of 3-aminopropyltrimethoxysilane (APTMS) with poly(amic acid) (PAA) composite solutions using a thermal imidization process. PAA was synthesized by a conventional condensation reaction of two diamines, 3,5-diaminobenzoic acid (DABA), which has a carboxylic acid side group, and 2,2′-bis(trifluoromethyl)benzidine (TFMB), with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc). The PAA–silica composite solutions were prepared by mixing PAA with carboxylic acid side groups and various amounts of APTMS in a sol–gel process in DMAc using hydrochloric acid as a catalyst. The obtained PI–silica composite films showed relatively good thermal stability, and the thermal stability increased with increasing APTMS content. The optical properties and in-plane coefficient of thermal expansion (CTE) values of the PI–silica composite films were investigated. The CTE of the PI–silica composite films changed from 52.0 to 42.1 ppm/°C as the initial content of APTMS varied. The haze values and yellowness indices of the composite films increased as a function of the APTMS content.
Buildup of Multi-Ionic Supramolecular Network Facilitated by In-Situ Intercalated Organic Montmorillonite in 1,2-Polybutadiene
Authors: Liu Jinhui , Li Di , Zhao Xiangshuai , Geng Jieting , Hua Jing , Wang Xin
Published: March 2019

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions.
Shock-Driven Decomposition of Polymers and Polymeric Foams
Authors: Dattelbaum Dana M. , Coe Joshua D.
Published: March 2019

Polymers and foams are pervasive in everyday life, as well as in specialized contexts such as space exploration, industry, and defense. They are frequently subject to shock loading in the latter cases, and will chemically decompose to small molecule gases and carbon (soot) under loads of sufficient strength. We review a body of work—most of it performed at Los Alamos National Laboratory—on polymers and foams under extreme conditions. To provide some context, we begin with a brief review of basic concepts in shockwave physics, including features particular to transitions (chemical reaction or phase transition) entailing an abrupt reduction in volume. We then discuss chemical formulations and synthesis, as well as experimental platforms used to interrogate polymers under shock loading. A high-level summary of equations of state for polymers and their decomposition products is provided, and their application illustrated. We then present results including temperatures and product compositions, thresholds for reaction, wave profiles, and some peculiarities of traditional modeling approaches. We close with some thoughts regarding future work.
Ascertainment of Surfactin Concentration in Bubbles and Foam Column Operated in Semi-Batch
Authors: Firmani Perna Rafael , Pereira Gonçalves Maria Carolina , Costapinto Santana Cesar
Published: March 2019

This paper describes a mathematical model for the convection, diffusion, and balance phenomena for predicting the depletion curves, i.e., variations in the timed surface-active molecule concentration for fractionation processes in bubbles and foam column, operated in semi-batch. The model was applied for the purification of the surfactin solution and the results were compared with experimental data. Gibbs adsorption curves were obtained for the biosurfactant at different temperatures, and then adjusted with estimated parameters, according to the Langmuir adsorption model. The gas bubble sizes were optically determined. The isotherm adsorption parameters and bubble average diameter are crucial for the attainment of the depletion curves, generated by the model described. The results demonstrate that the process is most effective when operating a column with reduced gas flow and low initial concentration. A top product with two or thirty times greater concentration than the initial one was achieved and the highest biosurfactant concentrations were attained for higher operating temperatures. It was also observed that bubble diameter increased with a higher gas flow. The adjustment obtained for the adsorption curves of Gibbs was satisfactory. Therefore, there was evidence that surfactin molecules adsorb in monolayers in the liquid–gas interface.
Paul, Timothy, and the Respectability Politics of Race: A Womanist Inter(con)textual Reading of Acts 16:1–5
Authors: Smith Mitzi J.
Published: March 2019

In this paper, I interpret the story of the Apostle Paul’s circumcision of Timothy in the New Testament text The Acts of the Apostles (16:1–5) from a womanist perspective. My approach is intersectional and inter(con)textual. I construct a hermeneutical dialogue between African American women’s experiences of race/racism, respectability politics, and the Acts’ narrative. In conversation with critical race theorists Naomi Zack, Barbara and Karen Fields, and black feminist E. Frances White, I discuss the intersection of race/racism, gender, geopolitical Diasporic space, and the burden and failure of respectability politics. Respectability politics claim that when non-white people adopt and exhibit certain proper behaviors, the reward will be respect, acceptance, and equality in the white dominated society, thereby ameliorating or overcoming race/racism. Race and racism are modern constructions that I employ heuristically and metaphorically as analytical categories for discussing the rhetorical distinctions made between Jews and Greeks/Gentiles, Timothy’s bi-racial status, and to facilitate comparative dialogue between Acts and African American women’s experiences with race and racism. I argue that Paul engages in respectability politics by compelling Timothy to be circumcised because of his Greek father and despite the Jerusalem Council’s decision that Gentile believers will not be required to be circumcised.
Municipal Solid Waste as a Source of Electric Power Generation in Colombia: A Techno-Economic Evaluation under Different Scenarios
Authors: Alzate Santiago , Restrepo-Cuestas Bonie , Jaramillo-Duque Álvaro
Published: March 2019

This work evaluates the techno-economic prefeasibility of waste to energy projects in Colombia using four different conversion technologies of incineration, gasification, anaerobic digestion and landfill gas. Three study cases were selected to represent typical urban centers in Colombia, which were namely Guayatá, Andes and Pasto. After feasible technologies were identified for each case, their energy recovery potential was calculated based on the mathematical models and publicly available information about the composition of the wastes produced in these three municipalities. A subsequent economic analysis was conducted by applying the incentives established in Law 1715 for projects involving non-conventional renewable energy sources. The cash flows produced by each technology in the three scenarios were evaluated to obtain the Internal Rate of Return (IRR), which was found to be influenced by the benefits of this legislation. However, the economic benefits were not significant in the small municipality of Guayatá. In turn, in Andes, a high electricity price (100 USD/MWh) would entail a positive IRR of 2.6%. In Pasto, which is the biggest city of the three, the maximum IRR of landfill gas and anaerobic digestion reached 13.59% and 14.27%, respectively. The results show that these types of projects can have positive economic results if tax and government incentives are taken into account.
Tight Fusion of a Monocular Camera, MEMS-IMU, and Single-Frequency Multi-GNSS RTK for Precise Navigation in GNSS-Challenged Environments
Authors: Li Tuan , Zhang Hongping , Gao Zhouzheng , Niu Xiaoji , El-sheimy Naser
Published: March 2019

Precise position, velocity, and attitude is essential for self-driving cars and unmanned aerial vehicles (UAVs). The integration of global navigation satellite system (GNSS) real-time kinematics (RTK) and inertial measurement units (IMUs) is able to provide high-accuracy navigation solutions in open-sky conditions, but the accuracy will be degraded severely in GNSS-challenged environments, especially integrated with the low-cost microelectromechanical system (MEMS) IMUs. In order to navigate in GNSS-denied environments, the visual–inertial system has been widely adopted due to its complementary characteristics, but it suffers from error accumulation. In this contribution, we tightly integrate the raw measurements from the single-frequency multi-GNSS RTK, MEMS-IMU, and monocular camera through the extended Kalman filter (EKF) to enhance the navigation performance in terms of accuracy, continuity, and availability. The visual measurement model from the well-known multistate constraint Kalman filter (MSCKF) is combined with the double-differenced GNSS measurement model to update the integration filter. A field vehicular experiment was carried out in GNSS-challenged environments to evaluate the performance of the proposed algorithm. Results indicate that both multi-GNSS and vision contribute significantly to the centimeter-level positioning availability in GNSS-challenged environments. Meanwhile, the velocity and attitude accuracy can be greatly improved by using the tightly-coupled multi-GNSS RTK/INS/Vision integration, especially for the yaw angle.
Community Science as a Pathway for Resilience in Response to a Public Health Crisis in Flint, Michigan
Authors: Carrera Jennifer S. , Key Kent , Bailey Sarah , Hamm Joseph A. , Cuthbertson Courtney A. , Lewis E. Yvonne , Woolford Susan J. , DeLoney E. Hill , Greene-Moton Ella , Wallace Kaneesha , Robinson DeWaun E. , Byers Ismael , Piechowski Patricia , Evans Luther , McKay Athena , Vereen Don , Sparks Arlene , Calhoun Karen
Published: March 2019

While the story of the Flint water crisis has frequently been told, even sympathetic analyses have largely worked to make invisible the significant actions of Flint residents to protect and advocate for their community. Leaving the voices of these stakeholders out of narratives about the crisis has served to deepen distrust in the community. Our project responds to these silences through a community-driven research study aimed explicitly at elevating the frame of Flint residents in and around the Flint water crisis. This paper describes the coming together of the research team, the overall project design for each of the three research efforts, and lessons learned. The three sub-projects include: (1) a qualitative analysis of community sentiment provided during 17 recorded legislative, media, and community events, (2) an analysis of trust in the Flint community through nine focus groups across demographic groups (African American, Hispanic, seniors, and youth) of residents in Flint, and (3) an analysis of the role of the faith-based community in response to public health crises through two focus groups with faith based leaders from Flint involved with response efforts to the water crisis. Our study offers insight for understanding trust in crisis, which could be valuable to other communities and researchers seeking to address similar situations. The project offers community science as a model for considering community engagement in research as part of the process of resilience.
The Sustainability of Cruise Tourism Onshore: The Impact of Crowding on Visitors’ Satisfaction
Authors: Sanz-Blas Silvia , Buzova Daniela , Schlesinger Walesska
Published: March 2019

The sustainability of cruise tourism has been questioned in relation to its negative effects on ports of call, among which crowding has recently become more pronounced. However, an understanding of how crowdedness influences cruise tourists’ experience onshore is lacking. The study analyzed online reviews on onshore experiences in the main European ports of call through Leximancer, an automated text analytics software. The results revealed that the perceived destination crowding was not always negatively evaluated by tourists, but was also discussed as a factor adding up to the authenticity of the visit under certain circumstances. Nevertheless, the evidence indicates that only human crowding might be positively assessed, while the spatial crowdedness was always reported as detracting from the enjoyment of the visit. The analysis also showed that the crowding phenomenon was represented differently in the accounts of the low, average and high satisfaction cruise tourists’ groups. The role of the guide, as well as the attractiveness of the sightseeing were identified as factors that can ameliorate the negative effect of crowding on the destination visit. The findings yield relevant implications for all actors involved in the cruise tourism activity, which should manage destination crowdedness in a more sustainably innovative way.
Response of Nitrogen Losses to Excessive Nitrogen Fertilizer Application in Intensive Greenhouse Vegetable Production
Authors: Zhao Hui , Li Xuyong , Jiang Yan
Published: March 2019

Excessive nitrogen fertilizer application in greenhouse vegetable production (GVP) is of scientific and public concern because of its significance to international environmental sustainability. We conducted a meta-analysis using 1174 paired observations from 69 publications on the effects of nitrogen fertilizer application and reducing nitrogen fertilizer application on the nitrogen losses on a broad scale. We found that the increase in nitrogen loss is much higher than that in production gain caused by excessive application of nitrogen fertilizer: nitrate leaching (+187.5%), ammonium leaching (+28.1%), total nitrogen leaching (+217.0%), nitrous oxide emission (+202.0%), ammonia emission (+176.4%), nitric oxide emission (+543.3%), yield (+35.7%) and nitrogen uptake (+24.5%). Environmental variables respond nonlinearly to nitrogen fertilizer application, with severe nitrate leaching and nitrous oxide emission when the application rate exceeds 570 kg N/ha and 733 kg/N, respectively. The effect of nitrogen fertilizer on yield growth decreases when the application rate exceeds 302 kg N/ha. Appropriate reduction in nitrogen fertilizer application rate substantially mitigates the environmental cost, for example, decreasing nitrate leaching (−32.4%), ammonium leaching (−6.5%), total nitrogen leaching (−37.3%), ammonia emission (−28.4%), nitrous oxide emission (−38.6%) and nitric oxide emission (−8.0%), while it has no significant effect on the nitrogen uptake and yield.
Barriers and Enablers for Short Sea Shipping in the Southern African Development Community
Authors: Konstantinus Abisai , Zuidgeest Mark , Christodoulou Anastasia , Raza Zeeshan , Woxenius Johan
Published: March 2019

The Southern African Development Community (SADC) region is an economic community comprised of 16 countries in Southern Africa with a goal to achieve development, peace, security, and economic growth. Developing the regional freight transport system is essential for accomplishing these objectives. This paper investigates the potential of short sea shipping (SSS) in an African context, highlighting policy initiatives related to SSS development and identifying barriers and enablers of SSS to support international trade in the SADC region. According to our findings, SSS has the theoretical potential to work in the SADC given the large geographic region, projected freight volumes, and customs and trade policies the SADC region is pursuing. Such a system would have three main roles: to offer unimodal freight transport between port cities, to offer the main leg of an intermodal route, and to offer feeder services to deep sea shipping in a hub-and-spoke cycle. However, freight transport in the SADC region has a number of shortfalls that need to be addressed—of note, port competitiveness, customs provisions, and policies for intra-regional trade require impetus. Additional work is required in terms of policy to support SSS. Furthermore, considering the importance of synergies, the role of policy makers in improving trust, and developing cooperation among transport chain members needs to be explored.
Recent Updates on Mouse Models for Human Immunodeficiency, Influenza, and Dengue Viral Infections
Authors: Krishnakumar Vinodhini , Durairajan Siva Sundara Kumar , Alagarasu Kalichamy , Li Min , Dash Aditya Prasad
Published: March 2019

Well-developed mouse models are important for understanding the pathogenesis and progression of immunological response to viral infections in humans. Moreover, to test vaccines, anti-viral drugs and therapeutic agents, mouse models are fundamental for preclinical investigations. Human viruses, however, seldom infect mice due to differences in the cellular receptors used by the viruses for entry, as well as in the innate immune responses in mice and humans. In other words, a species barrier exists when using mouse models for investigating human viral infections. Developing transgenic (Tg) mice models expressing the human genes coding for viral entry receptors and knock-out (KO) mice models devoid of components involved in the innate immune response have, to some extent, overcome this barrier. Humanized mouse models are a third approach, developed by engrafting functional human cells and tissues into immunodeficient mice. They are becoming indispensable for analyzing human viral diseases since they nearly recapitulate the human disease. These mouse models also serve to test the efficacy of vaccines and antiviral agents. This review provides an update on the Tg, KO, and humanized mouse models that are used in studies investigating the pathogenesis of three important human-specific viruses, namely human immunodeficiency (HIV) virus 1, influenza, and dengue.
Heterotypic Neuraminidase Antibodies Against Different A(H1N1) Strains are Elicited after Seasonal Influenza Vaccination
Authors: Mendez-Legaza Jose Manuel , Ortiz de Lejarazu Raúl , Sanz Ivan
Published: March 2019

Neuraminidase (NA) content is not standardized in current seasonal influenza vaccines; neither anti-NA antibodies (anti-NA Abs) are measured nor is it well-defined as a correlate of humoral protection. In this work, the presence of NA1 antibodies against classical A(H1N1) and A(H1N1) pdm09 subtypes was studied before and after vaccination with seasonal vaccines containing A/California/07/2009 strain (A(H1N1) pdm09 subtype). By Enzyme-Linked Lectin Assay (ELLA; Consortium for the Standardization of Influenza Seroepidemiology), we analyzed serum samples from two different cohorts (adults and elderly). The presence of anti-NA Abs at titers ≥1/40 against classical A(H1N1) and A(H1N1) pdm09 subtypes were frequently found in both age groups, in 81.3% and 96.3% of adults and elderly, respectively. The higher titers of anti-NA Abs (NAI titers) were detected more frequently against classical A(H1N1) strains according to the expected age when the first flu infection takes place. In this way, an Original Antigenic Sin phenomenon related to NA seems to be part of the immune response against flu. Seasonal-vaccination induced homologous seroconversion against NA of A(H1N1) pdm09 subtype in 52.5% and 55.0%, and increased the Geometric Mean Titers (GMTs) in 70.0% and 78.8% of adults and elderly, respectively. Seasonal vaccination also induced a heterotypic anti-NA Abs response against classical A(H1N1) strains (seroconversion at least in 8.8% and 11.3% of adults and elderly, respectively, and an increase in GMTs of at least 28.0% in both age groups). These anti-NA Abs responses occur even though the seasonal vaccine does not contain a standardized amount of NA. This work demonstrates that seasonal vaccines containing the A(H1N1) pdm09 subtype induce a broad antibody response against NA1, that may be a target for future influenza vaccines. Our study is one of the first to analyze the presence of Abs against NA and the response mediated by NAI titers after seasonal influenza vaccination.