bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of rhinoceros keratin using direct analysis in real time time‐of‐flight mass spectrometry and multivariate statistical analysis
Authors: Price Erin R. , McClure Pamela J. , Jacobs Rachel L. , Espinoza Edgard O.
Published: September 2018

Rationale

Trade in rhinoceros horn is regulated or banned internationally in recognition of its impact on wild populations worldwide. Enforcement of the laws and regulations depends on successfully identifying when violations occur, which is complicated by the presence of alternative/imitation rhinoceros horn keratin (e.g., bovid horn keratin). In this study, we assess the potential for Direct Analysis in Real Time (DART) ionization paired with Time‐Of‐Flight Mass Spectrometry (DART‐TOFMS) to classify different keratin types from four taxonomic groups: rhinoceros, bovid, domestic horse, and pangolin.

Methods

The spectra of 156 keratin samples from all five rhinoceros species (horn keratin), eight genera of bovids (horn keratin), domestic horses (hoof keratin), and all extant species of pangolins (scale keratin) were collected. Fisher ratio analysis identified the most important ions that characterized each class and these ions were used for the training model, which consisted of 143 spectra. Kernel Discriminant Analysis (KDA) was used to classify the different groups.

Results

The spectra collected for each taxonomic group are distinctive. The chemotypes demonstrate that the spectra of rhinoceros, bovids, and domestic horse are similar to each other, whereas the chemotypes of pangolins show a different chemical profile. The model built by KDA resolved each taxonomic group: 95% of samples were correctly assigned using leave‐one‐out cross validation. The 13 blind samples not used in model development were all correctly classified to taxonomic source.

Conclusions

DART‐TOFMS appears to be a reliable approach for taxonomic identification of keratin. This analysis can be carried out with a small sliver of keratin, with minimal sample preparation, inexpensively and quickly, making it a potential valuable tool for identification of rhinoceros horn and other keratin types.
On the sliding mode control of MIMO nonlinear systems: An input‐output approach
Authors: Sira‐Ramírez H. , Aguilar‐Orduña M.A. , Zurita‐Bustamante E.W.
Published: September 2018

We address the sliding mode control design problem for output reference trajectory tracking problems in the special class of MIMO flat systems known as static feedback linearizable systems. We assume unavailable system state components but rely on available inputs and measurable flat outputs. Each controller will largely ignore state and control input couplings by adopting a standard sliding mode controller scheme derived from the SISO case and used this as decoupled input‐to‐flat‐output model. The standard controller arises from a vastly simplified pure integration, additively perturbed, system. The simplified pure integration system controlled trajectories are shown to be time‐scale homotopically equivalent to those of the nonlinear flat system. The basic sliding surface coordinate function design is approached from the perspective of structural integral reconstructors requiring only the inputs and the flat outputs of the system. Integral structural reconstructors were introduced by Fliess et al for the control of linear SISO and MIMO systems, giving rise to the generalized proportional integral control method. Simulations are presented for SISO and MIMO systems and experimental results are reported for a two‐degree‐of‐freedom fully actuated robotic manipulator.
Leader‐following consensus of general linear fractional‐order multiagent systems with input delay via event‐triggered control
Authors: Ye Yanyan , Su Housheng
Published: September 2018

In this paper, the event‐triggered leader‐following consensus problem of general linear fractional‐order multiagent systems subject to input delay on directed graph is investigated. A distributed event‐triggered control protocol with input delay is proposed firstly. By applying the properties of the Mittag‐Leffler function, the technique of inequality, and the matrix theory, some consensus criteria for the fractional‐order multiagent systems are obtained. It is shown that the dynamic leader can be tracked by the followers for any bounded delay, and the followers receive and update their control protocol at some discrete time instants. Some simulation results are presented to illustrate the effectiveness of the theoretical analysis.
The Future Is Voice
Authors: Boonrod Arpapat , Ketavan Prachawan
Published: September 2018

Why brands should take notice
When artificial intelligence meets human intelligence
Authors: Bordenave Richard
Published: September 2018

Customer Experience insights
How technology is impacting jobs and market research
Authors: Pingitore Gina , Lorch Jackie , Hagel John
Published: September 2018

And how should researchers prepare for the coming changes?
Toward a critical theory of science, technology, engineering, and mathematics doctoral persistence: Critical capital theory
Authors: Bancroft Senetta F.
Published: September 2018

The proportion of Black, Latinx, and American Native individuals annually earning science, technology, engineering, and mathematics (STEM) doctoral degrees in the United States (US) has been enduringly and inequitably low for decades compared to their White peers. Despite the intransigent connection between race and STEM doctoral outcomes, US STEM education policy documents typically fail to identify racism as influencing this racial inequity. This paper presents critical capital theory (CCT)—an integration of critical race theory, forms of capital, and fictive kinship—to give racism full explanatory power within the context of US STEM doctoral outcomes. CCT proposes that access to large and affluent social networks containing supportive individuals who have knowledge of how to successfully navigate institutions of power is currently core to STEM doctoral success. This access reinforces STEM identity and belonging, but has been and continues to be primarily preserved for White students via an ever‐evolving system of racism. CCT proposes systems supporting STEM faculty’s consistent provision of high‐quality mentorship experiences for all their students—coupled with accountability for providing this mentorship—would result in more equitable STEM doctoral outcomes.
Poverty alleviation among persons with disabilities via United Nations' sustainable development goals in Ghana: Voices of stakeholders with disabilities
Authors: Opoku Maxwell P. , J‐F  , Swabey Karen , Pullen Darren , Dowden Tony
Published: September 2018

Consistently, it has been reported that persons with disabilities face multiple challenges in societies and thus it is important that deliberate intervention programs are initiated to empower them to overcome exclusion. The United Nations has taken the lead through the Sustainable Development Goals (SDGs) project, which is a framework for assisting countries and donors in their efforts to alleviate poverty. This article documented the experiences of persons with disabilities with respect to global efforts towards poverty reduction via SDGs. Face‐to‐face interviews were conducted with 48 individuals with disabilities (hearing loss n = 11, visual impairment n = 15, and physical disability n = 22) who were drawn from four districts in the Northern Region of Ghana. Analysis of the interview data revealed common themes related to hardship, poverty, limited access to education, and underemployment. The results indicated that the SDG project engendered little tangible improvement in the lives of persons with disabilities. The need for concerted efforts to address barriers faced by individuals with disabilities is discussed extensively.
Boosting the Electrochemical Performance of Li–S Batteries with a Dual Polysulfides Confinement Strategy
Authors: Yao Yu , Feng Wanlin , Chen Minglong , Zhong Xiongwu , Wu Xiaojun , Zhang Haibin , Yu Yan
Published: September 2018

Lithium–sulfur (Li–S) batteries have attracted more and more attention because they represent one of the most promising candidates to satisfy emerging energy storage demands. The biggest challenge regarding the application of the Li–S battery is to suppress the polysulfide shuttle while maintaining a high sulfur loading mass. Here, a dual polysulfide confinement strategy is designed by confinement of sulfur in polydopamine‐coated MXene nanosheets (denoted as S@Mxe@PDA) that performs as a high‐performance cathode for Li–S cells owing to their inherently high underlying metallic conductivity and chemical bonding and strong chemical adsorption to lithium polysulfides (LPs). This dual LPs confinement strategy is supported by the results of density functional theory calculations. It is demonstrated that the S@Mxe@PDA cathode exhibits outstanding electrochemical properties, including high reversible capacity (1044 mAh g−1 after 150 cycles at 0.2 C), superior rate capability (624 mAh g−1 at 6 C) and excellent cycling stability (556 mAh g−1 after 330 cycles at 0.5 C with 4.4 mg cm−2 sulfur loading). This work offers a facile and effective method for boosting Li–S batteries into practical applications.
Recent Developments in the Biosynthesis of Cu‐Based Recyclable Nanocatalysts Using Plant Extracts and their Application in the Chemical Reactions
Authors: Nasrollahzadeh Mahmoud , Ghorbannezhad Fatemeh , Issaabadi Zahra , Sajadi S. Mohammad
Published: September 2018

Copper nanoparticles (NPs) are one of the most commercialized nanomaterials. From the standpoint of nanotechnology copper‐based nanostructured materials have many applications in biological process, folk medicine, electronics, and industrial fields. With growing concern regarding the energy crisis and problems of chemical and physical procedures to prepare the metal nanoparticles, efforts for alternative traditional chemistry attracted particular considerations. A widespread of researches have studied on biological methods which do not generate hazardous waste and therefore, don't need the purification processes. Plants could be remarkably valuable to exploring the biogenic synthesis of metal nanoparticles. The aim of this review is to provide further insight in to connections between plant extracts and synthesis of copper NPs. The utilization of living plants for biosynthesis of metal nanoparticles (MNPs) is a cost‐effective and eco‐friendly procedure. To date, the obtained results demonstrated several aspects of the plant physiology and their relations to nanoparticle synthesis. This work describes the state of the art and future challenges in green synthesis of copper NPs. This review has proven recent elevation in the green synthesis of Cu NPs, CuO NPs, Cu2O NPs, CuS NPs, CuAl2O4 and immobilized copper nanoparticles on the numerous supports such as Natrolite, bentonite, perlite, ZnO, MgO, MnO2, reduced graphene oxide (RGO), and Fe3O4 by a wide range of plant extracts. Therefore, detailed description of green synthesis and stabilizing agents concerning copper nanoparticles using these green sources is presented. Also, the catalytic activities of synthesized Cu‐based recyclable nanocatalysts using various plant extracts in several chemical reactions such as oxidation, reduction, hydration, cyanation, cycloaddition, and coupling reactions were consciously investigated.
Development of High Performance Heterogeneous Catalysts for Selective Cleavage of C−O and C−C Bonds of Biomass‐Derived Oxygenates
Authors: Mizugaki Tomoo , Kaneda Kiyotomi
Published: September 2018

The environmental impact of CO2 emissions via the use of fossil resources as chemical feedstock and fuels has stimulated research to utilize renewable biomass feedstock. The biogenic compounds such as polyols are highly oxygenated and their valorization requires the new methods to control the oxygen to carbon ratio of the chemicals. The catalytic cleavage of C−O bonds and C−C bonds is promising methods, but the conventional catalyst systems encounter the difficulty to obtain the high yields of the desired products. This review describes our recent development of the high performance heterogeneous catalysts for the valorization of the biogenic chemicals such as glycerol, furfural, and levulinic acid via selective cleavage of C−O bonds and C−C bonds in the liquid‐phase. Selective C−O bond cleavage by hydrogenolysis enables production of various diols useful as engineering plastics, antifreeze, and cosmetics in high yields. The success of the selective C−C bond scission of levulinic acid can be applied to a wide range of the biogenic oxygenates such as carboxylic acids, esters, lactones, and primary alcohols, in which the selective C−C bond scission at adjacent to the oxygen functional groups are achieved. Furthermore, valorization of glycerol by selective acetylation and acetalization, and of levulinic acid by hydrogenation is described. Our catalysts show excellent performance compared to the reported catalysts in the aforementioned valorization.
Nanoarchitectonic‐Based Material Platforms for Environmental and Bioprocessing Applications
Authors: Ariga Katsuhiko , Jackman Joshua A. , Cho Nam‐Joon , Hsu Shan‐hui , Shrestha Lok Kumar , Mori Taizo , Takeya Jun
Published: September 2018

The challenges of pollution, environmental science, and energy consumption have become global issues of broad societal importance. In order to address these challenges, novel functional systems and advanced materials are needed to achieve high efficiency, low emission, and environmentally friendly performance. A promising approach involves nanostructure‐level controls of functional material design through a novel concept, nanoarchitectonics. In this account article, we summarize nanoarchitectonic approaches to create nanoscale platform structures that are potentially useful for environmentally green and bioprocessing applications. The introduced platforms are roughly classified into (i) membrane platforms and (ii) nanostructured platforms. The examples are discussed together with the relevant chemical processes, environmental sensing, bio‐related interaction analyses, materials for environmental remediation, non‐precious metal catalysts, and facile separation for biomedical uses.
Impact of mining on human health in and around mines
Authors: Yadav Akhilesh Kumar , Jamal Aarif
Published: September 2018

In the structure of the systematic investigation of the environment of the Singrauli coal field of the Singrauli and Sonbhadra Districts, mining activities are among the primary pollutant‐producing sources of particulate matter. In this study, the age group found to receive the highest dose—and to be at highest risk for adverse health effects—was children at the age of 1 year. Furthermore, the inhalation dose and health risks are 1.4 times higher for actual mine workers when they are in the mine areas than for persons in non‐mining, areas. Furthermore, inhalation doses were observed to be higher in summer than in winter and the rainy season.
Gamma irradiation of polyethylene nanocomposites for food packaging applications against stored‐product insect pests
Authors: Eyssa Hanan M. , Sawires Sameh G. , Senna Magdy M.
Published: September 2018

Films of high‐density polyethylene (HDPE) incorporated with different nanoparticles, ZnO or Ag, were prepared to protect food products from the stored‐product insect pests. The developed composites were irradiated at different radiation doses and the associated properties were investigated in terms of gel content percent, tensile mechanical properties, thermal properties, and morphology. The possible application of the irradiated products in food industry via the insect pest test was investigated. The gel content percentage of the irradiated HDPE films loaded with ZnO and Ag nanoparticles demonstrated higher values than those of unirradiated unloaded films and unirradiated loaded HDPE. The mechanical measurements indicated significant increments by loading with nanoparticles as well as by irradiation. The tensile strength raised up to about 177 and 158% by adding 2% ZnO and Ag, respectively. Conversely, the elongation percentage was decreased by increasing nanoparticle concentration and by radiation dose. Thermogravimetric analysis elaborated that the thermal stability of the nanocomposites was lesser than that of HDPE unloaded films, yet improved by irradiation. The insect pest test revealed that the adults of Sitophilus granarius could not penetrate the loaded and irradiated HDPE film. The most efficient formulation was reported for the HDPE films incorporated with 2% Ag irradiated with a dose of 75 kGy. J. VINYL ADDIT. TECHNOL., 25:E120–E129, 2019. © 2018 Society of Plastics Engineers
Comparing rotor plane induction determined from full‐scale measurements and CFD simulations
Authors: Ghadirian Amin , Larsen Gunner Chr. , Troldborg Niels
Published: September 2018

This paper investigates the flow field in the rotor plane of a full‐scale operating wind turbine using full‐scale light detection and ranging (LiDAR) measurements for the first time. Comparison of the measured flow field with results from large eddy simulations (LES) combined with an actuator line approach is also presented for in‐depth study of the induction field in the rotor plane. The measurements include data from two synchronized LiDAR systems—one scanning the undisturbed upstream inflow field and one measuring in the rotor plane. The standard deviation of the mean of velocity time series are and presented as a measure of reliability. The method for calculating the axial velocity based on the line‐of‐sight velocity is explained and the uncertainty of such method is presented. The process of calculating the yaw misalignment is described.

The time‐averaged and phase‐averaged axial velocity and induction factors are presented relative to radius and azimuth, and the general behavior is described relative to the flow regimes around the blades, tower and nacelle. Simulations and measurements are compared with special emphasis on the flow structures in the vicinity of the individual rotor blades. A convincing agreement between measurements and simulations is demonstrated. The uncertainties originated from the imprecise positions and angles of the measurement instruments are shown. The uncertainties are limited to the middle parts of the blades between 15 m to 25 m from the root. In addition, longer selected time series show smaller uncertainties. This proves the reliability of the application of the methodology for even longer time series.
Survey of neural network‐based models for short‐term traffic state prediction
Authors: Do Loan N. N. , Taherifar Neda , Vu Hai L.
Published: September 2018

Traffic state prediction is a key component in intelligent transport systems (ITS) and has attracted much attention over the last few decades. Advances in computational power and availability of a large amount of data have paved the way to employ advanced neural network (NN) models for ITS, including deep architectures. There have been various NN‐based approaches proposed for short‐term traffic state prediction that are surveyed in this article, where the existing NN models are classified and their application to this area is reviewed. An in‐depth discussion is provided to demonstrate how different types of NNs have been used for different aspects of short‐term traffic state prediction. Finally, possible further research directions are suggested for additional applications of NN models, especially using deep architectures, to address the dynamic nature in complex transportation networks.

This article is categorized under:

Technologies > Prediction

Technologies > Machine Learning

Application Areas > Science and Technology
Market and nonmarket valuation of North Carolina's tundra swans among hunters, wildlife watchers, and the public
Authors: Frew Kristin N. , Peterson M. Nils , Sills Erin , Moorman Christopher E. , Bondell Howard , Fuller Joseph C. , Howell Douglas L.
Published: September 2018

Wildlife‐related tourism represents an important and growing economic sector for many rural communities and may be inadequately considered during regional planning. Providing robust estimates of wildlife values can help address this challenge. We used both market and nonmarket valuation methods to estimate the value of tundra swans (Cygnus columbianus) in North Carolina, USA, and compared tundra swan values among hunters, wildlife watchers, and general public. Wildlife watchers reported the greatest willingness‐to‐pay (US$35.2/wildlife watcher/yr), followed by hunters (US$30.53/hunter/yr), and residents (US$16.27/resident/yr). We used the Impact Analysis for Planning system software to estimate market values or economic activity associated with tundra swans. Tundra swan hunters spent an average of US$408.34/hunter/year. Depending on assumptions over the substitutability of tundra swan hunting, we estimate that it generates value added of between US$306,155/year and US$920,161/year for the state economy. Wildlife watchers spent an average of US$171.25/wildlife watcher/year. We estimate that this generates value added of between US$14 million/year and US$42.9 million/year for the state economy, again depending on assumptions about whether watching tundra swans would be substituted with other leisure activities in eastern North Carolina or out‐of‐state. Compared with studies of international nature tourism, we found relatively low leakage rates (i.e., loss of economic benefits outside the study region), suggesting that enhancing opportunities for hunting and wildlife‐viewing may be an effective economic development strategy for rural areas in the United States. Presenting both market and nonmarket values provides a more complete picture of the value of wildlife and may facilitate more effective management decisions; therefore, we recommend that both market and nonmarket values be considered to optimize tradeoffs between development and wildlife recreation. © 2018 The Wildlife Society.
Selective Synthesis and Complexation of Novel N,N′‐Alkylene‐Bridged Bis(5‐pyridyltetrazole)
Authors: Voitekhovich Sergei V. , Mosalkova Anastasiya P. , Lyakhov Alexander S. , Ivashkevich Ludmila S. , Schmorl Sara , Kersting Berthold , Ivashkevich Oleg A.
Published: September 2018

A novel N,N′‐alkylene‐bridged bis(5‐pyridyltetrazole) ligand, namely 2,5‐bis[5‐(2‐pyridyl)‐tetrazol‐2‐yl]‐2,5‐dimethylhexane (bpt), was prepared by regioselective N2‐alkylation of 5‐(2‐pyridyl)tetrazole with 2,5‐dimethylhexane‐2,5‐diol in perchloric acid. The ligand bpt was found to react with copper(II) chloride to give the dinuclear complex [Cu2(bpt)Cl4]. According to single‐crystal X‐ray analysis of the complex, bpt acts as a chelating ligand, coordinated by the metal through the tetrazole ring N4 and the pyridine ring nitrogen atoms. In the complex molecule, two copper atoms are linked by double chlorido bridges, and ligand bpt plays the role of the third bridge. The temperature‐dependent magnetic susceptibility measurements of the complex revealed that the copper(II) ions were weakly antiferromagnetically coupled showing a coupling constant J of –1.04 cm–1.
Self-consistent analytic solutions in twisted ℂPN−1 model in the large-N limit
Authors: Nitta Muneto , Yoshii Ryosuke
Published: September 2018

Abstract

We construct self-consistent analytic solutions in the ℂP

N −1 model in the large-N limit, in which more than one Higgs scalar component take values inside a single or multiple soliton on an infinite space or on a ring, or around boundaries of a finite interval.
Heavy quark jet fragmentation
Authors: Dai Lin , Kim Chul , Leibovich Adam K.
Published: September 2018

Abstract

In this paper we study the fragmentation of a parton into a jet containing a heavy quark. When heavy quarks are involved in a jet, the quark mass can lead to a numerically significant correction to the jet cross section and its substructure. With this motivation, we calculated the heavy quark mass effects to next-to-leading order in αs on the fragmentation functions to a jet (FFJs) and the jet fragmentation functions (JFFs), where the former describes fragmentation of parton into a jet and the latter describes fragmenting processes inside a jet. The finite size of the heavy quark mass does not change the ultraviolet behaviors, but it can give significant corrections to the finite contributions. When we take the zero mass limit, we find that the FFJs and the JFFs reproduce established results for massless partons. If we define the heavy quark jet as one that include at least one heavy (anti-)quark, the tagged heavy quark jet production is sensitive to the heavy quark mass and produces large logarithms of the mass. Taking advantage of the FFJs and JFFs, we formulate a factorization theorem for heavy quark jet production in order to resum these large logarithms systematically. As an application, we study inclusive b-jet production and show phenomenological implications due to keeping a non-zero quark mass.
225Ac-PSMA-617 in chemotherapy-naive patients with advanced prostate cancer: a pilot study
Authors: Sathekge Mike , Bruchertseifer Frank , Knoesen Otto , Reyneke Florette , Lawal Ismaheel , Lengana Thabo , Davis Cindy , Mahapane Johncy , Corbett Ceceila , Vorster Mariza , Morgenstern Alfred
Published: September 2018

Background

A remarkable therapeutic efficacy has been demonstrated with 225Ac-prostate-specific membrane antigen (PSMA)-617 in heavily pre-treated metastatic castration-resistant prostate cancer (mCRPC) patients. We report our experience with 225Ac-PSMA-617 therapy in chemotherapy-naïve patients with advanced metastatic prostate carcinoma.

Methods

Seventeen patients with advanced prostate cancer were selected for treatment with 225Ac-PSMA-617 in 2-month intervals, with initial activity of 8 MBq, then de-escalation to 7 MBq, 6 MBq or 4 MBq in cases of good response. In one patient, activity was escalated to 13 MBq in the third cycle. Fourteen patients had three treatment cycles administered, while in three patients treatment was discontinued after two cycles due to good response. Six out of 17 patients received additional treatments after the third cycle. Prostate-specific antigen (PSA) was measured every 4 weeks for PSA response assessment. 68Ga-PSMA-PET/CT was used for functional response assessment before each subsequent treatment cycle. Serial full blood count, renal function test, and liver function were obtained to determine treatment-related side effects.

Results

Good antitumor activity assessed by serum PSA level and 68Ga-PSMA-PET/CT was seen in 16/17 patients. In 14/17 patients, PSA decline ≥90% was seen after treatment, including seven patients with undetectable serum PSA following two (2/7) or three cycles (5/7) cycles of 225Ac-PSMA-617. Fifteen of 17 patients had a > 50% decline in lesions avidity for tracer on 68Ga-PSMA-PET/CT including 11 patients with complete resolution (PET-negative and either stable sclerosis on CT for bone or resolution of lymph node metastases) of all metastatic lesions. Grade 1/2 xerostomia was seen in all patients, and none was severe enough to lead to discontinuation of treatment. One patient had with extensive bone marrow metastases and a background anemia developed a grade 3 anemia while another patient with solitary kidney and pre-treatment grade 3 renal failure developed grade 4 renal toxicity following treatment. The group presented with significant palliation of bone pain and reduced toxicity to salivary glands due to de-escalation.

Conclusions

225Ac-PSMA-617 RLT of chemotherapy-naïve patients with advanced metastatic prostate carcinoma led to a ≥ 90% decline in serum PSA in 82% of patients including 41% of patients with undetectable serum PSA who remained in remission 12 months after therapy. The remarkable therapeutic efficacy reported in this study could be achieved with reduced toxicity to salivary glands due to de-escalation of administered activities in subsequent treatment cycles. This necessitates further exploration for informing clinical practice and clinical trial design.
Laparoscopy in Rwanda: A National Assessment of Utilization, Demands, and Perceived Challenges
Authors: Robertson Faith , Mutabazi Zeta , Kyamanywa Patrick , Ntakiyiruta Georges , Musafiri Sanctus , Walker Tim , Kayibanda Emmanuel , Mukabatsinda Constance , Scott John , Costas‐Chavarri Ainhoa
Published: September 2018

Background

Laparoscopy has proven to be feasible and effective at reducing surgical morbidity and mortality in low resource settings. In Rwanda, the demand for and perceived challenges to laparoscopy use remain unclear.

Methods

A mixed‐methods study was performed at the four Rwandan national referral teaching hospitals. Retrospective logbook reviews (July 2014–June 2015) assessed procedure volume and staff involvement. Web‐based surveys and semi‐structured interviews investigated barriers to laparoscopy expansion.

Results

During the study period, 209 laparoscopic procedures were completed: 57 (27.3%) general surgery cases; 152 (72.7%) ob/gyn cases. The majority (58.9%, 125/209) occurred at the private hospital, which performed 82.6% of cholecystectomies laparoscopically (38/46). The three public hospitals, respectively, performed 25% (7/28), 15% (12/80), and 0% (denominator indeterminate) of cholecystectomies laparoscopically. Notably, the two hospitals with the highest laparoscopy volume relied on a single surgeon for more than 85% of cases. The four ob/gyn departments performed between 4 and 87 laparoscopic cases (mostly diagnostic). Survey respondents at all sites listed a dearth of trainers as the most significant barrier to performing laparoscopy (65.7%; 23/35). Other obstacles included limited access to training equipment and courses. Equipment and material costs, equipment functionality, and material supply were perceived as lesser barriers. Twenty‐two interviews revealed widespread interest in laparoscopy, insufficient laparoscopy exposure, and a need for trainers.

Conclusion

While many studies identify cost as the most prohibitive barrier to laparoscopy utilization in low resource settings, logbook review and workforce perception indicate that a paucity of trainers is currently the greatest obstacle in Rwanda.
Improved acid-stress tolerance of Lactococcus lactis NZ9000 and Escherichia coli BL21 by overexpression of the anti-acid component recT
Authors: Zhu Zhengming , Ji Xiaomei , Wu Zhimeng , Zhang Juan , Du Guocheng
Published: September 2018

Acid accumulation caused by carbon metabolism severely affects the fermentation performance of microbial cells. Here, different sources of the recT gene involved in homologous recombination were functionally overexpressed in Lactococcus lactis NZ9000 and Escherichia coli BL21, and their acid-stress tolerances were investigated. Our results showed that L. lactis NZ9000 (ERecT and LRecT) strains showed 1.4- and 10.4-fold higher survival rates against lactic acid (pH 4.0), respectively, and that E. coli BL21 (ERecT) showed 16.7- and 9.4-fold higher survival rates than the control strain against lactic acid (pH 3.8) for 40 and 60 min, respectively. Additionally, we found that recT overexpression in L. lactis NZ9000 improved their growth under acid-stress conditions, as well as increased salt- and ethanol-stress tolerance and intracellular ATP concentrations in L. lactis NZ9000. These findings demonstrated the efficacy of recT overexpression for enhancing acid-stress tolerance and provided a promising strategy for insertion of anti-acid components in different hosts.
Cigarette Smoking and All-Cause and Cause-Specific Adult Mortality in the United States
Authors: Lariscy Joseph T. , Hummer Robert A. , Rogers Richard G.
Published: September 2018

This study illuminates the association between cigarette smoking and adult mortality in the contemporary United States. Recent studies have estimated smoking-attributable mortality using indirect approaches or with sample data that are not nationally representative and that lack key confounders. We use the 1990–2011 National Health Interview Survey Linked Mortality Files to estimate relative risks of all-cause and cause-specific mortality for current and former smokers compared with never smokers. We examine causes of death established as attributable to smoking as well as additional causes that appear to be linked to smoking but have not yet been declared by the U.S. Surgeon General to be caused by smoking. Mortality risk is substantially elevated among smokers for established causes and moderately elevated for additional causes. We also decompose the mortality disadvantage among smokers by cause of death and estimate the number of smoking-attributable deaths for the U.S. adult population ages 35+, net of sociodemographic and behavioral confounders. The elevated risks translate to 481,887 excess deaths per year among current and former smokers compared with never smokers, 14 % to 15 % of which are due to the additional causes. The additional causes of death contribute to the health burden of smoking and should be considered in future studies of smoking-attributable mortality. This study demonstrates that smoking-attributable mortality must remain a top population health priority in the United States and makes several contributions to further underscore the human costs of this tragedy that has ravaged American society for more than a century.
Trends and Outcomes After Prenatal Diagnosis of Congenital Cardiac Defects: Experience of a Dedicated Fetal Medicine Centre from South India
Authors: Devadasan Shyama , Balakrishnan Bijoy , Batra Meenu , Sreeja P. S. , Patil Swapneel N. , Gopinathan K. K.
Published: September 2018

The primary objective of the study was to present a 5-year data on the outcomes after prenatal diagnosis of CHD. This is a retrospective descriptive study, conducted in the fetal medicine unit of an academic tertiary care referral centre in South India. The details of all cases with a prenatal diagnosis of fetal cardiac lesions from January 2012 through December 2016 were collected. All cases were systematically analyzed for type of lesion, associated malformations, chromosomal abnormalities, prognosis of the lesion, the decision taken by the couples and the information regarding post natal outcome, wherever available. Prenatally diagnosed fetal cardiac lesions were identified in 310 cases. In 220 (76.1%) cases, the couple opted for termination of pregnancy. In this group, 52% of them had an isolated cardiac defect with good prognosis. In the rest of the 69 cases who decided to continue, 7 cases had an IUD. In the 62 cases that culminated in a live birth, 46 cases opted for postnatal cardiac care. Corrective surgery was attempted in 18 neonates with 2 resulting in neonatal death. Prenatal diagnosis of isolated CHD provides an opportunity for an improved immediate neonatal outcome. A thorough evaluation for extracardiac and genetic abnormality will facilitate better utilization of health care resources by triaging patients with isolated CHD having good prognosis for targeted postnatal care. Also, antenatal pediatric cardiology counselling will enable the couple to make decisions regarding postnatal management options.
Temporal variations of cryoconite holes and cryoconite coverage on the ablation ice surface of Qaanaaq Glacier in northwest Greenland
Authors: Takeuchi Nozomu , Sakaki Ryutaro , Uetake Jun , Nagatsuka Naoko , Shimada Rigen , Niwano Masashi , Aoki Teruo
Published: September 2018

Cryoconite holes are water-filled cylindrical holes formed on ablation ice surfaces and commonly observed on glaciers worldwide. Temporal changes of cryoconite holes characteristically <5 cm in diameter were monitored with a time-lapse interval camera over 15 d during the melting season on Qaanaaq Glacier in northwest Greenland. The holes drastically changed their dimensions and synchronously collapsed twice during the study period. When the holes collapsed, the coverage of cryoconite on the ice surface increased from 1.0 to 3.5% in the field of view of the camera, and then decreased again to 0.4% after the holes reformed. Comparison with meteorological data showed that the collapses occurred in cloudy and rainy or windy weather conditions, corresponding to low shortwave solar radiation (68–126 W m−2, 40–55% of the incoming flux). In contrast, holes developed in sunny conditions correspond to high solar radiation (186–278 W m−2, 63–88%). Results suggest that the dimensions of holes drastically changed depending on the weather conditions and that frequent cloudy, warm and windy conditions would cause a decay of holes and weathering crust, inducing an increase in the cryoconite coverage on the ice, consequently darkening the glacier surface.
The impact of dynamic roughness elements on marginally separated boundary layers
Authors: Servini P. , Smith F. T. , Rothmayer A. P.
Published: September 2018

It has been shown experimentally that dynamic roughness elements – small bumps embedded within a boundary layer, oscillating at a fixed frequency – are able to increase the angle of attack at which a laminar boundary layer will separate from the leading edge of an airfoil (Grager et al., in 6th AIAA Flow Control Conference, 2012, pp. 25–28). In this paper, we attempt to verify that such an increase is possible by considering a two-dimensional dynamic roughness element in the context of marginal separation theory, and suggest the mechanisms through which any increase may come about. We will show that a dynamic roughness element can increase the value of

$\unicode[STIX]{x1D6E4}_{c}$

as compared to the clean airfoil case;

$\unicode[STIX]{x1D6E4}_{c}$

represents, mathematically, the critical value of the parameter

$\unicode[STIX]{x1D6E4}$

below which a solution exists in the governing equations and, physically, the maximum angle of attack possible below which a laminar boundary layer will remain predominantly attached to the surface. Furthermore, we find that the dynamic roughness element impacts on the perturbation pressure gradient in two possible ways: either by decreasing the magnitude of the adverse pressure peak or by increasing the streamwise extent in which favourable pressure perturbations exist. Finally, we discover that the marginal separation bubble does not necessarily have to exist at

$\unicode[STIX]{x1D6E4}=\unicode[STIX]{x1D6E4}_{c}$

in the time-averaged flow and that full breakaway separation can therefore occur as a result of the bursting of transient bubbles existing within the length scale of marginal separation theory.
Axial mixing and vortex stability to in situ radial injection in Taylor–Couette laminar and turbulent flows
Authors: Wilkinson Nikolas A. , Dutcher Cari S.
Published: September 2018

Taylor–Couette flows have been widely studied in part due to the enhanced mixing performance from the variety of hydrodynamic flow states accessible. These process improvements have been demonstrated despite the traditionally limited injection mechanisms from the complexity of the Taylor–Couette geometry. In this study, using a newly designed, modified Taylor–Couette cell, axial mass transport behaviour is experimentally determined over two orders of magnitude of Reynolds number. Four different flow states, including laminar and turbulent Taylor vortex flows and laminar and turbulent wavy vortex flows, were studied. Using flow visualization techniques, the measured dispersion coefficient was found to increase with increasing $Re$, and a single, unified regression is found for all vortices studied. In addition to mass transport, the vortex structures’ stability to radial injection is also quantified. A dimensionless stability criterion, the ratio of injection to diffusion time scales, was found to capture the conditions under which vortex structures are stable to injection. Using the stability criterion, global and transitional stability regions are identified as a function of Reynolds number, $Re$.
Hydrodynamic interactions between aerosol particles in the transition regime
Authors: Corson James , Mulholland G. W. , Zachariah M. R.
Published: September 2018

We present a method for calculating the hydrodynamic interactions between particles in the kinetic (or transition regime), characterized by non-negligible particle Knudsen numbers. Such particles are often present in aerosol systems. The method is based on our extended Kirkwood–Riseman theory (Corson et al., Phys. Rev. E, vol. 95 (1), 2017c, 013103), which accounts for interactions between spheres using the velocity field around a translating sphere as a function of Knudsen number. Results for the two-sphere problem at small Knudsen numbers are in good agreement with those obtained using Felderhof’s interaction actions for mixed slip-stick boundary conditions, which are accurate to order

$r^{-7}$

(Felderhof, Physica A, vol. 89 (2), 1977, pp. 373–384). The strength of the interactions decreases with increasing Knudsen number. Results for two fractal aggregates demonstrate that one can apply a point force approach for interactions between particles in the transition regime; the interaction tensor is similar to the Oseen tensor for continuum flow. Using this point force approach, we present an analysis for the settling of an unbounded cloud of particles. Our analysis shows that for sufficiently high volume fractions and cloud radii, the cloud behaves as a gas droplet in continuum flow even when the individual particles are small relative to the mean free path of the gas. The method presented here can be applied in a Brownian dynamics simulation analogous to Stokesian dynamics to study the behaviour of a dense aerosol system.
On viscous propulsion in active transversely isotropic media
Authors: Cupples G. , Dyson R. J. , Smith D. J.
Published: September 2018

Very low Reynolds number propulsion is a topic of enduring interest due to its importance in biological systems such as sperm migration in the female reproductive tract. Motivated by the fibrous nature of cervical mucus, several recent studies have considered the effect of anisotropic rheology; these studies have generally employed the classical swimming sheet model of G. I. Taylor. The models of Cupples et al. (J. Fluid Mech. vol. 812, 2017, pp. 501–524) and Shi & Powers (Phys. Rev. Fluids vol. 2, 2017, 123102) consider related problems which in a common limit (passive, slightly anisotropic) make different predictions regarding how swimming speed depends on alignment angle. In the present paper we find that this discrepancy is due to missing terms in the analysis of Cupples et al., and that when these terms are correctly included, the models agree in their common limit. We further explore the predictions of the corrected model for both passive and active cases; it is found that for certain combinations of alignment angle and activity parameter, propulsion is halted; in other cases the small amplitude asymptotic expansion is no longer valid, motivating future numerical study.
Wind turbine wakes over hills
Authors: Shamsoddin Sina , Porté-Agel Fernando
Published: September 2018

Understanding and predicting the behaviour of wind turbine wake flows over hills is important for optimal design of wind-farm configurations on topography. In this study, we present an analytical modelling framework together with large-eddy simulation (LES) results to investigate turbine wakes over two-dimensional hills. The analytical model consists of two steps. In the first step, we deal with the effect of the pressure gradient on the wake evolution; and in the second step, we consider the effect of the hill-induced streamline distortion on the wake. This model enables us to obtain the wake recovery rate, the mean velocity and velocity deficit profiles and the wake trajectory in the presence of the hill. Moreover, we perform LES to test our model and also to obtain new complementary insight about such flows. Especially, we take advantage of the LES data to perform a special analysis of the behaviour of the wake on the leeward side of the hill. It is found that the mainly favourable pressure gradient on the windward side of the hill accelerates the wake recovery and the adverse pressure gradient on the leeward side decelerates it. The wake trajectory for a hill of the same height as the turbine’s hub height is found to closely follow the hill profile on the windward side, but it maintains an almost constant elevation (a horizontal line) downstream of the hilltop. The trajectory of the wake on the leeward side is also studied for a limiting case of an escarpment, and it is shown that an internal boundary layer forms on the plateau which leads to an upward displacement of the wake centre. Finally, a parametric study of the position of the turbine with respect to the hill is performed to further elucidate the effect of the hill-induced pressure gradient on the wind turbine wake recovery.
Workgroup accord and change-oriented behavior in public service organizations: Mediating and contextual factors
Authors: Campbell Jesse W
Published: September 2018

Workgroup relationships are characterized by interdependence and intensity and can produce powerful norms that shape how work is performed. This study focuses on the effect of workgroup accord, defined as positive exchange, cooperation, and consensus among workgroup members, on change-oriented behavior in public service organizations. Change-oriented behavior denotes discretionary corrective or creative initiatives on the part of employees, and workgroup accord is hypothesized to increase change-oriented behavior both directly and indirectly via organizational commitment. The theoretical model is operationalized using survey data collected from employees of the Australian Public Service. The results of regression analysis are consistent with the hypothesis that workgroup accord positively influences organizational commitment, which in turn facilitates change-oriented behavior. However, a negative direct effect renders the total effect of workgroup accord on change-oriented behavior non-significant. Additionally, the findings suggest that innovation climate and employee performance agreement efficacy each positively moderate the negative relationship between workgroup accord and change-oriented behavior.
Dramatic reduction in size of the lowland Macquarie River in response to Late Quaternary climate-driven hydrologic change
Authors: Hesse Paul P. , Williams Rory , Ralph Timothy J. , Larkin Zacchary T. , Fryirs Kirstie A. , Westaway Kira E. , Yonge David
Published: September 2018

Palaeochannels of lowland rivers provide a means of investigating the sensitivity of river response to climate-driven hydrologic change. About 80 palaeochannels of the lower Macquarie River of southeastern Australia record the evolution of this distributive fluvial system. Six Macquarie palaeochannels were dated by single-grain optically stimulated luminescence. The largest of the palaeochannels (Quombothoo, median age 54 ka) was on average 284 m wide, 12 times wider than the modern river (24 m) and with 21 times greater meander wavelength. Palaeo-discharge then declined, resulting in a younger, narrower, group of palaeochannels, Bibbijibbery (125 m wide, 34 ka), Billybingbone (92 m, 20 ka), Milmiland (112 m, 22 ka), and Mundadoo (86 m, 5.6 ka). Yet these channels were still much larger than the modern river and were continuous downstream to the confluence with the Barwon-Darling River. At 5.5 ka, a further decrease in river discharge led to the formation of the narrow modern river, the ecologically important Macquarie Marshes, and Marra Creek palaeochannel (31 m, 2.1 ka) and diminished sediment delivery to the Barwon-Darling River as palaeo-discharge fell further. The hydrologic changes suggest precipitation was a driving forcing on catchment discharge in addition to a temperature-driven runoff response.