bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid organ transplant–specific antibiogram in a tertiary pediatric hospital in Canada
Authors: Kitano Taito , Science Michelle , Nalli Nadya , Timberlake Kathryn , Allen Upton , Teoh Chia Wei , Campigotto Aaron
Published: February 2021

SOT recipients are more vulnerable to infections with antimicrobial‐resistant organisms, and therefore, it may be useful for transplant centers to create transplant‐specific antibiograms to direct empirical antimicrobial regimens and monitor trends in antimicrobial resistance. SOT‐specific antibiograms were created using antimicrobial susceptibility data on isolates from 2012 to 2018 at The Hospital for Sick Children, Toronto, Ontario, Canada. The CLSI guidelines were followed to generate the antibiograms except that results from 2 years of data were pooled on a rolling basis to achieve larger sample sizes. The 3 most frequent organisms in one analysis period of the SOT antibiogram were Escherichia coli (average sample size ±standard deviation; n = 28.7 ± 3.8), Staphylococcus aureus (n = 27.8 ± 5.0), and Pseudomonas aeruginosa (non‐CF) (n = 19.8 ± 8.8). For E.coli, susceptibilities in the SOT antibiogram were significantly lower than those in the hospital‐wide antibiogram in 2017–2018 for ampicillin (27% vs 47%; p = .014), piperacillin/tazobactam (55% vs 88%; p < .001), cefotaxime (59% vs 89%; p < .001), ciprofloxacin (71% vs 88%; p = .007), and trimethoprim‐sulfamethoxazole (41% vs 69%; p = .001), but not significantly different for aminoglycosides and meropenem. In the SOT antibiogram of E. coli, decreased susceptibility trend was confirmed in some antibiotics, including piperacillin/tazobactam (83% in 2012–2013 vs 55% in 2017–2018). At our center, the solid organ transplant–specific antibiogram revealed important differences in E. coli susceptibilities and trends in antimicrobial resistance. Developing a SOT antibiogram will assist in revising and improving empiric treatment guidelines as well as monitoring antimicrobial resistance in this population.
Effects of Online–Offline Service Integration on e‐Healthcare Providers: A Quasi‐Natural Experiment
Authors: Huang Ni , Yan Zhijun , Yin Haonan
Published: February 2021

E‐healthcare platforms start to integrate medical services across online and offline channels, where providers can perform online consultations, schedule patients’ offline visits, synchronize relevant medical records, and finally, answer online inquiries regarding follow‐up and recovery anytime and anywhere within one operations management function (i.e., online–offline service integration). In this study, we seek to quantify the effects of online–offline service integration on the e‐healthcare providers’ demand and reputational outcomes, noting that it is not altogether clear how the service integration function will affect the providers who adopt such a function in e‐healthcare platforms. Leveraging a quasi‐natural experiment on an e‐healthcare platform, we conducted difference‐in‐differences analyses in tandem with a variety of matching strategies, including propensity score matching and look‐ahead propensity score matching. Furthermore, we explored the moderating roles of provider‐specific characteristics. Our results reveal a set of robust and interesting findings: (i) e‐healthcare providers, on average, experience increases in online demand and decreases in offline demand post online–offline service integration; (ii) the service integration function also improves the professional reputation of participating providers; (iii) the impact of channel integration on the outcomes is weaker for providers with lower (vs. higher) professional titles; and (iv) the providers who specialize in treating chronic (vs. acute) diseases experience greater increases in online demand and reputational outcomes, yet insignificant changes in offline demand. This work contributes to related prior literatures on healthcare operations management, e‐healthcare, and online–offline channel integration, offering design implications for the service operations of e‐healthcare platforms.
Adapting our Flood Risk Policies to Changing Conditions
Authors: Kousky Carolyn , Kunreuther Howard , Xian Siyuan , Lin Ning
Published: February 2021

Flooding causes more damage and severely impacts more people worldwide than any other natural disaster. Flood risk in many parts of the United States is projected to increase due to both continued floodplain development and climate change. Many of our institutions and public policies are not designed to address these changing risk conditions. The practice of grandfathering insurance premiums in the National Flood Insurance Program (NFIP)—allowing an insured to keep a lower rate even when risk has increased—is one such policy. We link a flood hazard model to a flood insurance premium calculator in order to provide illustrative calculations of the possible impact of grandfathering on program revenue and policyholder premiums due to sea level rise for a New York City neighborhood. We conclude by discussing how to preserve the financial soundness of the NFIP while addressing the affordability of insurance in the face of increasing flood risk.
Introduction to the Forum: Bordering, Ordering and Othering
Authors: Van Melik Rianne
Published: February 2021

‘Bordering, Ordering and Othering’ (2002) by Henk van Houtum and Ton van Naerssen is one of the most cited and read papers published in TESG in the last two decades. This Introduction to the third TESG Forum briefly summarises the key points of the paper, followed by contributions of four border scholars who reflect upon the paper’s contribution and continued relevance to the field, but also discuss some of its shortcomings. Van Houtum closes this Forum with a reflection on these commentaries. Jointly, these five scholars also present a future border research agenda.
Heterogeneous impacts of finance on firm exports: Evidence from export deregulation in a large developing country
Authors: Cheng Dong , Hu Zhongzhong , Tan Yong
Published: February 2021

This paper investigates the heterogeneous effects of finance on firm exports through the lens of differential exporting modes. China's WTO accession leads to an export deregulation, which empowers private domestic firms with low registered capital to export directly. This quasinatural experiment encourages firms switching from indirect to direct exporting, and thus provides an ideal setting to explore the heterogeneous effects of finance on exports among switchers and non‐switchers. Applying the difference‐in‐differences (DID) approach to a comprehensive survey data on Chinese manufacturing firms, we find that finance improves exports more for firms switching from indirect to direct exporting, relative to continuous indirect exporters. Our mechanism analysis shows that finance manifests a more pronounced encouraging effect on firm‐level operation efficiency and productivity among switchers. Moreover, we show that the heterogeneous effects of finance on exports among switchers and non‐switchers are more pronounced in the post‐WTO accession period. The time‐varying heterogeneous impacts suggest an economic loss caused by the export distortion before China's WTO accession because it prevents productive yet financially constrained private domestic firms from direct exporting.
Job creation and job destruction: The effect of trade shocks on U.S. manufacturing employment
Authors: Liang Yang
Published: February 2021

This paper studies the effect of export expansion on the US labour market over the last two decades. Exploiting foreign emerging markets’ unilateral liberalisation, this paper provides new empirical evidence for the importance of export expansion to the US labour market at the industry level. Using a novel instrumental variable strategy, the result confirms that US exports played a critical role in supporting manufacturing employment. Reduced‐form estimates imply that US exports to different markets created more than 1.6 million manufacturing jobs between 1991 and 2007, which is comparable to the estimated job losses attributed to the import competition from China. Meanwhile, there is substantial heterogeneity in this positive employment effect across export destinations and industries. Industries not only respond differently to various export shocks, but could also experience differential employment growth facing the same export shock. I find that the job creation effect is larger for industries with a higher initial share of workers who are older, less‐educated or non‐white, and performing routine‐based tasks. In addition, the effect is more pronounced for industries that had higher labour market concentration.
Patterns of red‐cell transfusion use in obstetric practice in Sweden 2003‐2017: A nationwide study
Authors: Brynolf Anne , Zhao Jingcheng , Wikman Agneta , Öberg Sara , Sandström Anna , Edgren Gustaf
Published: February 2021

Background

There is a paucity of data on patterns of red‐cell transfusions in obstetrical care, but some studies have suggested an increase in transfusion rates during the last decade. The purpose of this study was to investigate maternal characteristics, temporal trends and hospital variations in red‐cell use in a large contemporary obstetric cohort in Sweden.

Study design and methods

Nationwide observational cohort study of maternal red‐cell transfusions for all deliveries in Sweden between 2003 and 2017.

Results

The proportion of deliveries that received red‐cell transfusions was stable during the study period, although the number of red‐cell units administered per delivery declined. Among transfused women, most received a low‐volume transfusion of 1 or 2 units. Red‐cell transfusion was more common among the nulliparous, for instrumental and caesarean deliveries, and with increased maternal age. We saw large variations in transfusion rates between hospitals in Sweden, despite adjusting for age and parity.

Conclusions

In comparison to other high‐resource countries we see a high proportion of deliveries with maternal red‐cell transfusions. However, we do not see an increase in red‐cell use over time.
Automatic Lithofacies Classification with t-SNE and K-Nearest Neighbors Algorithm
Authors: Potratz Guilherme Loriato , Canchumuni Smith Washington Arauco , Castro Jose David Bermudez , Potratz Júlia , Pacheco Marco Aurélio C.
Published: February 2021

One of the critical processes in the exploration of hydrocarbons is the identification and prediction of lithofacies that constitute the reservoir. One of the cheapest and most efficient ways to carry out that process is from the interpretation of well log data, which are often obtained continuously and in the majority of drilled wells. The main methodologies used to correlate log data to data obtained in well cores are based on statistical analyses, machine learning models and artificial neural networks. This study aims to test an algorithm of dimension reduction of data together with an unsupervised classification method of predicting lithofacies automatically. The performance of the methodology presented was compared to predictions made with artificial neural networks. We used the t-Distributed Stochastic Neighbor Embedding (t-SNE) as an algorithm for mapping the wells logging data in a smaller feature space. Then, the predictions of facies are performed using a KNN algorithm. The method is assessed in the public dataset of the Hugoton and Panoma fields. Prediction of facies through traditional artificial neural networks obtained an accuracy of 69%, where facies predicted through the t-SNE + K-NN algorithm obtained an accuracy of 79%. Considering the nature of the data, which have high dimensionality and are not linearly correlated, the efficiency of t SNE+KNN can be explained by the ability of the algorithm to identify hidden patterns in a fuzzy boundary in data set. It is important to stress that the application of machine learning algorithms offers relevant benefits to the hydrocarbon exploration sector, such as identifying hidden patterns in high-dimensional datasets, searching for complex and non-linear relationships, and avoiding the need for a preliminary definition of mathematic relations among the model’s input data.
Classifying the emotional speech content of participants in group meetings using convolutional long short-term memory network
Authors: Morgan Mallory M. , Bhattacharya Indrani , Radke Richard J. , Braasch Jonas
Published: February 2021

Emotion is a central component of verbal communication between humans. Due to advances in machine learning and the development of affective computing, automatic emotion recognition is increasingly possible and sought after. To examine the connection between emotional speech and significant group dynamics perceptions, such as leadership and contribution, a new dataset (14 group meetings, 45 participants) is collected for analyzing collaborative group work based on the lunar survival task. To establish a training database, each participant's audio is manually annotated both categorically and along a three-dimensional scale with axes of activation, dominance, and valence and then converted to spectrograms. The performance of several neural network architectures for predicting speech emotion are compared for two tasks: categorical emotion classification and 3D emotion regression using multitask learning. Pretraining each neural network architecture on the well-known IEMOCAP (Interactive Emotional Dyadic Motion Capture) corpus improves the performance on this new group dynamics dataset. For both tasks, the two-dimensional convolutional long short-term memory network achieves the highest overall performance. By regressing the annotated emotions against post-task questionnaire variables for each participant, it is shown that the emotional speech content of a meeting can predict 71% of perceived group leaders and 86% of major contributors.
Group Dance and Motivational Coaching for Walking: A Physical Activity Program for South Asian Indian Immigrant Women Residing in the United States
Authors: Daniel Manju , Marquez David , Ingram Diana , Fogg Louis
Published: February 2021

Background: South Asian Indian immigrants residing in the United States are at high risk of cardiovascular disease (prevalence ≥35%), diabetes (prevalence 45.4%), and stroke (prevalence 26.5%). This study examined the effect of culturally relevant physical activity interventions on the improvement of physiological measures and average daily steps in at-risk midlife South Asian Indian immigrant women. Methods: In this 2-arm interventional research design, the dance (n = 25) and the motivational phone calls group (n = 25), attended social cognitive theory–based motivational workshops every 2 weeks for the first 12 weeks. Data for weight, waist circumference, blood pressure, blood sugar, cholesterol level, and 12-lead electrocardiogram were collected at the baseline, 12 weeks, and 24 weeks. Results: Significant differences were seen in body weight (F2,94 = 4.826, P = .024; ), waist circumference (F2,92 = 7.496, P = .001; ), systolic blood pressure (F2,94 = 19.865, P = .000; ), triglyceride (F2,94 = 11.111, P = .000; ), cholesterol (F2,94 = 8.925, P = .001; ), blood sugar level (F2,94 = 8.851, P = .000; ), and average daily steps across both intervention groups over time (F2,96 = 30.94, P = .000; ). Conclusion: Culturally relevant motivational workshops with Indian dance and walking are an innovative approach to increasing lifestyle physical activity among South Asian Indian immigrant women.
Speedy robots gather spectra for sky surveys
Authors: Clery Daniel
Published: February 2021

Telescopes retrofitted with hundreds of optical fibers dissect the light of stars and galaxies.
Study shows winners, losers as desert warms
Authors: Pennisi Elizabeth
Published: February 2021

In 100-year record, small mammals burrow to beat the heat, but birds either fly away or die.
A hydrophobic FeMn@Si catalyst increases olefins from syngas by suppressing C1 by-products
Authors: Xu Yanfei , Li Xiangyang , Gao Junhu , Wang Jie , Ma Guangyuan , Wen Xiaodong , Yang Yong , Li Yongwang , Ding Mingyue
Published: February 2021

Keeping water away

Syngas, a mixture of carbon monoxide (CO) and hydrogen, allows nonpetroleum resources such as biomass and natural gas to be converted to chemical products through Fischer-Tropsch synthesis. However, for the production of olefins, a key feedstock for other chemicals, about 50% of the CO is transformed to carbon dioxide and methane. Xu
et al.
decreased the selectivity for these undesired by-products to under 25% by modifying their catalyst, nanoparticles of iron doped with manganese and coated with a silica, with methyl groups (see the Perspective by Xie). This hydrophobic surface shortens the retention time of water on the catalyst surface to avoid the unwanted side reactions, and also suppresses oxidation of the metal carbide catalyst that forms under reaction conditions.

Science
, this issue p.
610
; see also p.
577
Phosphorylation and chromatin tethering prevent cGAS activation during mitosis
Authors: Li Tuo , Huang Tuozhi , Du Mingjian , Chen Xiang , Du Fenghe , Ren Junyao , Chen Zhijian J.
Published: February 2021

Keeping cGAS silent

Cells detect microbial and self-DNA in the cytosol as a danger signal that triggers immune and inflammatory responses. Paradoxically, a large fraction of a DNA-sensing enzyme called cGAS is tightly associated with the chromatin, especially during mitosis. Li
et al.
uncovered two mechanisms that prevent cGAS from being activated by the chromatin DNA (see the Perspective by Ablasser). First, cGAS is hyperphosphorylated as cells enter mitosis, thereby inhibiting its DNA-binding and liquid-liquid phase separation, which promotes cGAS activation. Second, chromatin-bound cGAS is unable to oligomerize, a process required for its activation. Together, these mechanisms ensure cGAS inactivation during cell division to prevent autoimmune reactions.

Science
, this issue p.
eabc5386
; see also p.
1204
Exposure to climate change drives stability or collapse of desert mammal and bird communities
Authors: Riddell E. A. , Iknayan K. J. , Hargrove L. , Tremor S. , Patton J. L. , Ramirez R. , Wolf B. O. , Beissinger S. R.
Published: February 2021

Microhabitat matters

Understanding how our warming climate affects vulnerable species is of paramount importance. However, predicting responses is complicated because species are complex and may adapt or respond in distinct ways. Riddell
et al.
compared a century-old dataset on species richness in the Mojave against modern surveys to measure climate-related changes in bird and small mammal communities. They found little change in mammal richness or occupancy but large declines across birds. They attribute these differences to differences in microclimate opportunities: Specifically, mammals can mitigate temperature impacts through burrowing, whereas birds are generally more exposed.

Science
, this issue p.
633
Fecal microbiota transplant overcomes resistance to anti–PD-1 therapy in melanoma patients
Authors: Davar Diwakar , Dzutsev Amiran K. , McCulloch John A. , Rodrigues Richard R. , Chauvin Joe-Marc , Morrison Robert M. , Deblasio Richelle N. , Menna Carmine , Ding Quanquan , Pagliano Ornella , Zidi Bochra , Zhang Shuowen , Badger Jonathan H. , Vetizou Marie , Cole Alicia M. , Fernandes Miriam R. , Prescott Stephanie , Costa Raquel G. F. , Balaji Ascharya K. , Morgun Andrey , Vujkovic-Cvijin Ivan , Wang Hong , Borhani Amir A. , Schwartz Marc B. , Dubner Howard M. , Ernst Scarlett J. , Rose Amy , Najjar Yana G. , Belkaid Yasmine , Kirkwood John M. , Trinchieri Giorgio , Zarour Hassane M.
Published: February 2021

New fecal microbiota for cancer patients

The composition of the gut microbiome influences the response of cancer patients to immunotherapies. Baruch
et al.
and Davar
et al.
report first-in-human clinical trials to test whether fecal microbiota transplantation (FMT) can affect how metastatic melanoma patients respond to anti–PD-1 immunotherapy (see the Perspective by Woelk and Snyder). Both studies observed evidence of clinical benefit in a subset of treated patients. This included increased abundance of taxa previously shown to be associated with response to anti–PD-1, increased CD8
+
T cell activation, and decreased frequency of interleukin-8–expressing myeloid cells, which are involved in immunosuppression. These studies provide proof-of-concept evidence for the ability of FMT to affect immunotherapy response in cancer patients.

Science
, this issue p.
602
, p.
595
; see also p.
573
Ultrafast generation of optical hyperbolicity
Authors: Deng Shaozhi , Chen Huanjun
Published: February 2021

A new strategy actively controls the trapping and manipulation of light
Electric field–tunable superconductivity in alternating-twist magic-angle trilayer graphene
Authors: Hao Zeyu , Zimmerman A. M. , Ledwith Patrick , Khalaf Eslam , Najafabadi Danial Haie , Watanabe Kenji , Taniguchi Takashi , Vishwanath Ashvin , Kim Philip
Published: February 2021

A twisty trilayer

The discovery of superconductivity in bilayers consisting of graphene sheets twisted with respect to each other by just the right “magic” angle has inspired enormous interest in twisted materials. Hao
et al.
constructed twisted trilayer graphene, in which the middle layer is twisted with respect to the bottom layer and the top layer is roughly parallel to the bottom layer (see the Perspective by Yazdani). Such trilayers exhibited superconductivity that was tunable by an external electric field and consistent with having an unconventional nature.

Science
, this issue p.
1133
; see also p.
1098
The origins of 'Oumuamua
Extraterrestrial: The First Sign of Intelligent Life Beyond Earth
Avi Loeb
Houghton Mifflin Harcourt, 2021. 240 pp.
Authors: Greenbaum Dov
Published: February 2021

A high-profile astronomer argues that the strange interstellar object may be an alien signal
A genome to celebrate
Authors: Fraser Claire M.
Published: February 2021

This week,
Science
celebrates the impending 20th anniversary of the publication of the draft human genome sequence—a landmark achievement by any measure. The American Association for the Advancement of Science (AAAS, the publisher of
Science
) also looks forward to next week's annual meeting, whose theme is “Understanding Dynamic Ecosystems.” At first glance, these two events may seem unrelated. But the successful completion of the human genome sequence ushered in biology's era of “big science” and created a research ecosystem for tackling complex, technology-driven, and data-intensive multidisciplinary projects that continue to improve our understanding of cancer, the microbiome, the brain, and other areas of biology.
Fatal Waterhouse-Friderichsen syndrome in an adult due to serogroup YNeisseria meningitidis
Authors: Carvalho Rúben , Henriques Fernando , Teixeira Sónia , Coimbra Paulo
Published: February 2021

Waterhouse-Friderichsen syndrome (WFS), defined as severe adrenal insufficiency due to bilateral adrenal gland haemorrhagic necrosis, occurred in a 59-year-old woman. An underlying serogroup YNeisseria meningitidis(NM) infection was diagnosed, with a rapid progression to purpura fulminans, disseminated intravascular coagulation and WFS. Intensive treatment including fluid resuscitation, broad-spectrum antibiotic therapy, ventilatory support, platelet and factor replacement were administered. The meningococcaemia in the presence of WFS had a fulminant progression, leading to a fatal outcome within 24 hours of symptom onset. This case details the diagnosis and management challenges of the WFS, a rare complication of NM septicaemia, and describes the identification of a NM serogroup that is rare in Portugal in middle-aged patients.
Primary versus secondary nature of mesenteric neuroendocrine tumours
Authors: Park Ariel , Martin Alicia , Carlos Ramos , Neychev Vladimir
Published: February 2021

Neuroendocrine tumours (NETs) are rare group of malignancy that originate from neuroendocrine cells present throughout the body. Most patients with NET first present with symptoms associated with metastasis, and up to 20% of patients have unknown primary site of tumour. Most common metastatic sites for small intestine NETs (SI-NETs) are the locoregional lymph nodes and liver. Although mesenteric metastasis through direct extension or lymphatic spread from SI-NETs is common, mesenteric extranodal involvement is extremely rare, and its biology and primary versus secondary nature are not well understood. Due to their small size and location, SI-NETs are frequently undetected on anatomical imaging or indium-111-pentetreotide single-photon emission computed tomography/CT (Octreoscan) and are difficult to be found via endoscopy. Gallium-68-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-octreotate positron emission tomography (68Ga-DOTATATE PET)/CT has been increasingly used for accurate staging, unknown primary tumour site localisation and appropriate management planning. We present a case of an incidentally found mesenteric NET with occult SI-NETs localised preoperatively by68Ga-DOTATATE PET/CT.
Metastatic neuroendocrine tumour presenting as a testicular mass
Authors: Heijkoop Bridget , Perera Marlon , Kelly Brian D , Bolton Damien
Published: February 2021

In this manuscript, we describe a rare case of neuroendocrine tumour metastatic to the testicle, presenting with testicular mass as an isolated symptom. We describe the investigations and management leading us to this uncommon histological diagnosis and explore its significance and impact on further management.
Rare paraneoplastic syndromes in digestive systems caused by lung cancer
Authors: Kamimura Hiroteru , Iwasaki Tomohiro , Hayashi Kazunao , Terai Shuji
Published: February 2021

We observed a rare case of two different digestive paraneoplastic syndromes that improved with the treatment of the neoplasms. The first syndrome was chronic intestinal pseudo-obstruction (CIPO), which is a subtype of paraneoplastic syndromes called a paraneoplastic neurological syndrome (PNS). The second was Stauffer’s syndrome, which is a unique paraneoplastic syndrome characterised by non-metastatic intrahepatic cholestasis associated with neoplasms. Here, we report the case of a 55-year-old man who presented with two concurrent paraneoplastic syndromes in the digestive system. The intestinal pseudo-obstruction and elevated biliary enzyme levels improved as the lung cancer responded to chemotherapy. In this case, CIPO as a PNS led to the detection of lung cancer. To our knowledge, this is the first report of Stauffer’s syndrome caused by lung adenocarcinoma.
Perianal Paget’s disease: one century later and still a challenge
Authors: Guidi Gonçalo João , Pinto de Sousa João , Marques Rita , Ferreira Cátia
Published: February 2021

Perianal Paget disease (PPD) is a rare neoplastic condition defined by the presence of atypical Paget cells in the perianal skin, the aetiology of which remains largely unknown. It can be divided in primary forms, arising as an intraepithelial disease or manifestation of an underlying skin adenocarcinoma or secondary forms resulting from epidermotropic spread or metastasis of a concealed carcinoma. Indeed, because of its rarity, clear options regarding the treatment of these patients are yet to be clarified. A high level of suspicion is needed whenever dealing with any unhealed perianal skin lesions and, therefore, the need for close long-term follow-up must be highlighted. Herein, two cases of PPD, one primary and another secondary, treated at the same institution, are presented in an attempt to document the involved complexity and to bring further insight into the understanding of this entity.
Cuboid nutcracker fracture in a 9-year-old child
Authors: Sassine Tannous Jorge , Terra Bernardo Barcellos , Giordano Vincenzo , Ejnisman Benno
Published: February 2021

A 9-year-old girl presented to the emergency department reporting intense pain and inability to bear weight on her left foot after a classmate tripped over it. Imaging studies confirmed a fracture of the cuboid bone due to compression of the lateral column of the foot (also known as nutcracker fracture). The patient was treated surgically, with direct reduction of the compression fracture and definitive fixation with two Kirschner wires. Cuboid nutcracker fracture is rare in children and adolescents, and potential consequences can occur if it is not correctly diagnosed and adequately managed. Literature on this type of fracture is scarce, along with information on treatment options and results over medium-term and long-term follow-up. We describe this case and review the literature on this particular topic.
A new positive SARS-CoV-2 test months after severe COVID-19 illness: reinfection or intermittent viral shedding?
Authors: Tuan Jessica , Spichler-Moffarah Anne , Ogbuagu Onyema
Published: February 2021

We present a case of a patient who had a history of severe coronavirus disease (COVID-19) 4 months prior to this current presentation and, after a long asymptomatic period, subsequently tested positive for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by a RNA PCR assay, after several interval negative SARS-CoV-2 RNA tests. We present this potential case of SARS-CoV-2 reinfection in order to incite discussion around differentiating persistent infection with intermittent viral shedding and reinfection, as well as to discuss evolving knowledge and approaches to the clinical management, follow-up molecular testing and treatment of COVID-19 reinfection.
A Parallel Machine Scheduling Problem Maximizing Total Weighted Early Work
Authors: Choi Byung-Cheon , Park Myoung-Ju , Kim Kyung Min , Min Yunhong
Published: February 2021

We consider the total weighted early work maximization problem on identical machines in parallel such that the weights are identical, or the due date is the same. First, we present an approach to solve the case with a fixed number of machines in pseudo-polynomial time. Then, we develop approximation algorithms for the two cases with identical weights and with a common due date. For the case with identical weights, furthermore, we show that the parallel-machine and a single-machine cases are strongly NP-hard and weakly NP-hard, respectively, even if the due date of each job is equal to the processing time multiplied by a constant.
Multispinon excitations in the spin S = 1/2 antiferromagnetic Heisenberg model
Authors: LIU Yu-Liang
Published: February 2021

With the commutation relations of the spin operators, we first write out the equations of motion of the spin susceptibility and related correlation functions that have a hierarchical structure, then under the “soft cut-off” approximation, we give a set of equations of motion of spin susceptibilities for a spin [Formula: see text] antiferromagnetic Heisenberg model that is independent of whether or not the system has a long-range order in the low energy/temperature limit. Applying for a chain, a square lattice and a honeycomb lattice, respectively, we obtain the upper and the lowest boundaries of the low-lying excitations by solving this set of equations. For a chain, the upper and the lowest boundaries of the low-lying excitations are the same as that of the exact ones obtained by the Bethe ansatz, where the elementary excitations are the spinon pairs. For a square lattice, the spin wave excitation (magnons) resides in the region close to the lowest boundary of the low-lying excitations, and the multispinon excitations take place in the high-energy region close to the upper boundary of the low-lying excitations. For a honeycomb lattice, we have one kind of “mode” of the low-lying excitation. The present results obey the Lieb–Schultz–Mattis theorem, and they are also consistent with recent neutron scattering observations and numerical simulations for a square lattice.
A Layer-Wise Ensemble Technique for Binary Neural Network
Authors: Xi Jiazhen , Yamauchi Hiroyuki
Published: February 2021

Binary neural networks (BNNs) have drawn much attention because of the most promising techniques to meet the desired memory footprint and inference speed requirements. However, they still suffer from the severe intrinsic instability of the error convergence, resulting in increase in prediction error and its standard deviation, which is mostly caused by the inherently poor representation with only two possible values of [Formula: see text]1 and [Formula: see text]1. In this work, we have proposed a cost-aware layer-wise ensemble method to address the above issue without incurring any excessive costs, which is characterized by (1) layer-wise bagging and (2) cost-aware layer selection for the bagging. One of the experimental results has shown that the proposed method reduces the error and its standard deviation by 15% and 54% on CIFAR-10, respectively, compared to the BNN serving as a baseline. This paper demonstrated and discussed such error reduction and stability performance with high versatility based on the comparison results under the various cases of combinations of the network base model with the proposed and the state-of-the-art prior techniques while changing the network sizes and datasets of CIFAR-10, SVHN, and MNIST for the evaluation.
Adaptively Allocating Constraint-Handling Techniques for Constrained Multi-objective Optimization Problems
Authors: Yang Ning , Liu Hai-Lin
Published: February 2021

For solving constrained multi-objective optimization problems (CMOPs), an effective constraint-handling technique (CHT) is of great importance. Recently, many CHTs have been proposed for solving CMOPs. However, no single CHT can outperform all kinds of CMOPs. This paper proposes an algorithm, namely, ACHT-M2M, which adaptively allocates the existing CHTs in an M2M framework for solving CMOPs. To be more specific, a CMOP is first decomposed into several constrained multi-objective optimization subproblems by ACHT-M2M. Each subproblem has a subpopulation in a subregion. CHT for each subregion is adaptively allocated according to a proposed composite performance measure. Population for the next generation is selected from subregions by selection operators with different CHTs and the obtained nondominated feasible solutions in each generation are used to update a predefined archive. ACHT-M2M assembles the advantages of different CHTs and makes them cooperate with each other. The proposed ACHT-M2M is finally compared with the other 12 representative algorithms on benchmark CMOPs and the experimental results further confirm the effectiveness of ACHT-M2M for solving CMOPs.
ν − ν interactions in supernovae environments as a function of density and temperature
Authors: Colombi M. P. , Civitarese O. , Penacchioni A. V.
Published: February 2021

Neutrinos in astrophysical environments, such as Supernovae (SNe), may interact through pair interactions. These interactions are density and temperature-dependent. Under certain conditions, a neutrino-condensate may form. In this work, we have adapted the separable nonlocal pairing interactions to the SN conditions and studied the temperature and density dependence of the pairing gap as well as the collective response with respect to these variables. We have applied the Bogoliubov transformations and solved the Bardeen, Cooper and Schrieffer (BCS) equations to construct the free quasi-particle sector of the Hamiltonian. The residual two-quasi-particle terms have been treated by applying the Tamm–Dancoff approximation (TDA) and random-phase approximation (RPA), suited to the extended neutrino media. With this, we have constructed neutrino energy distributions both in the superfluid and normal regimes and extracted critical values of the density and temperature.
Local wave numbers on an n-spheres
Authors: Gutti Sashideep , Thiruvikraman P. K. , Raviteja K. , Haque Asrarul
Published: February 2021

We consider Eigen-functions of the Laplace–Beltrami Operator on n-Spheres and characterize them in terms of their local plane wave behavior. We estimate the local spectrum of wave numbers by approximating the Spherical harmonics in the locally flat neighborhood around a point on the Spheres. These local wave numbers are shown to obey an interesting Pythagorean type relation. Based on this relation, we propose a question whether there are integer triples for 2-spheres and their generalization to n-spheres. We apply the local spectrum to define quantities such as phase velocity and group velocity on a sphere and outline the relevance of the analysis for the case fields on de Sitter space.
Recognition of complex and multiple power quality disturbances using wavelet packet-based fast kurtogram and ruled decision tree algorithm
Authors: Mahla Rajendra , Khan Baseem , Mahela Om Prakash , Singh Anup
Published: February 2021

This paper introduces an algorithm based on wavelet packet supported fast kurtogram and decision rules for the identification and classification of complex power quality (PQ) disturbances. Features are extracted from the signals using fast kurtogram, envelope of filtered voltage signal and amplitude spectrum of squared envelop. Proposed algorithm can be implemented for the recognition of the complex PQ disturbances, which include the combination of voltage sag and harmonics, voltage momentary interruption (MI) and oscillatory transient (OT), voltage MI and harmonics, voltage sag and impulsive transient (IT), voltage sag, OT, IT and harmonics. Proposed work has been performed using the MATLAB software. Performance of the algorithm is compared with performance of algorithm supported by discrete wavelet transform (DWT) and fuzzy C-means clustering (FCM).
A mathematical study of a tuberculosis model with fractional derivatives
Authors: Abboubakar Hamadjam , Kumar Pushpendra , Erturk Vedat Suat , Kumar Anoop
Published: February 2021

In this work, we use a Predictor–Corrector method to implement and derive an iterative solution of an existing Tuberculosis (TB) model with two fractional derivatives, namely, Caputo–Fabrizio fractional derivative and the new generalized Caputo fractional derivative. We begin by recalling some existing results such as the basic reproduction number [Formula: see text] and the equilibrium points of the model. Then, we study the global asymptotic stability of disease-free equilibrium of the fractional models. We also prove, for each fractional model, the existence and uniqueness of solutions. An iterative solution of the two models is computed using the Predictor–Corrector method. Using realistic parameter values, we perform numerical simulations for different values of the fractional order. Simulation results permit to conclude that the new generalized Caputo fractional derivative provides a more realistic analysis than the Caputo–Fabrizio fractional derivative and the classical integer-order TB model.
Oscillatory Properties for Second-Order Impulsive Neutral Dynamic Equations with Positive and Negative Coefficients on Time Scales
Authors: Zhang Shuang , Li Qiaoluan
Published: February 2021

We study oscillatory properties for second-order impulsive neutral dynamic equations with positive and negative coefficients on time scales. By using variable substitution, we obtain sufficient conditions for several dynamic equations to be oscillatory.
Determinants and Prevalence of Tobacco Smoking among Medical Students at Jazan University, Saudi Arabia
Authors: Alkhalaf Mohammed , Suwyadi Abdullatif , AlShamakhi Eissa , Oribi Hassan , Theyab Zain , Sumayli Ibrahim , Yassin Abuobaida , Aqeeli Abdulwahab , Alqassim Ahmad , Mohamed Haniki
Published: February 2021

Tobacco smoking has a significant role in health deterioration worldwide; it can lead to many dangerous diseases. Tobacco smoking among medical students is common worldwide, but the prevalence and determinants vary from one community to another. Data from medical students in Saudi Arabia is limited. This study was conducted to estimate the prevalence and determinants of smoking among medical students at the College of Medicine, Jazan University, Saudi Arabia. A cross-sectional study using a self-administered electronic survey was conducted to estimate tobacco smoking’s prevalence and characteristics among medical students at Jazan University. The survey includes information on the gender, academic year, academic performance, type of tobacco smoking, and age of onset of the participants’ tobacco smoking. Other data, like the prevalence of passive smoking and social factors, were considered, too. The sample size was 354, 51.7% males and 48.3% females, students with a response rate of 38.02%. The prevalence of smoking among medical students was 12.4%, while passive smoking prevalence was 39.9% of all medical students. The research shows that 18.6% of male and 5.9% of female medical students were active smokers. Regarding the type of tobacco, we found that 47% of male smokers used waterpipe, while the percentage among female smokers using waterpipe reached 77.8%. The age of onset of smoking for 34.9% of the smokers was between 18 and 21 years old. The prevalence of smoking is inversely proportional to the GPA. Additionally, 71.1% of the smokers did not have a smoker friend, and only 13.3% of the smokers were motivated to quit. University age is critical for smoking habits, and the smoking cessation rate was low. More campaigns should be done in universities to increase smoking cessation awareness, and smoking cessation clinics should be activated at universities.
The Influence of Longitudinal Force on the Internal Force Distribution and Deformation Coordination Mechanism for Segment Lining
Authors: Songyu Cao , Kun Feng , Xun Liu , Chuan He , Mingqing Xiao
Published: February 2021

A series of local prototype tests are conducted on the Sutong GIL (Gas‐Insulated Line) and Shiziyang Tunnel. These tests investigate the redistribution law of segment deformation and the bending moment during construction. The results reveal that the transfer ability of deformation and the bending moment improve with an increase in the longitudinal force. Stage characteristics are observed for the effect of the longitudinal force on the opening of the circumferential joints. Segments are fully contacted for the circumferential joints when the joint opening is not observed. The frictions between the segments are the key factors for the bending moment and segment deformation control. The opening of the circumferential joint with an increase in the joint opening then becomes the primary control factor. The transfer ability becomes stable when the load continues increasing after mortise and tenon contact. Better transfer ability occurs with a general segment with four pairs of mortises and tenons. This was presented as a smaller value of an increasing rate and the stable magnitude of the joint opening. From the perspective of practical engineering, mortises and tenons can be added to the vault to increase the load and deformation transfer ability of the general segment after the loss of the longitudinal force.
Numerical Simulation of Deep Foundation Pit Construction under Complex Site Conditions
Authors: Liu Huifen , Li Kezeng , Wang Jianqiang , Cheng Chunxiang
Published: February 2021

Based on the deep foundation pit project of Laoguancun station of Wuhan rail transit line 16 and according to the engineering characteristics of the construction conditions and the site surrounding the environment, the method of combining field monitoring and finite element numerical simulation is adopted to analyze the law of stress and deformation of the deep foundation pit during excavation and support construction; it includes the horizontal displacement of the underground diaphragm wall, supporting axial force, and the ground surface settlement, which can be compared with measured data. Finally, some suggestions for monitoring and construction of the deep foundation pit in the subway station have been put forward and have certain reference value and practical guiding significance for the design and construction of similar engineering projects. The deformation monitoring of the retaining structure at the middle of the long side of the foundation pit should be strengthened during the construction process.
Numerical and Field Investigations on Rockburst Risk Adjacent to Irregular Coal Pillars and Fault
Authors: He Zhi-long , Lu Cai-ping , Zhang Xiu-feng , Wang Chao , Wang Bao-qi , Zhou Tao
Published: February 2021

Irregular coal pillars are often reserved in the upper coal seam in multiseam mining due to the limitation of geological conditions and mining methods. Diffused and transmitted stress in the pillars will form the stress concentrated areas in the lower coal seam and will increase the risk of rockburst. Based on the upper irregular pillars and fault encountered in the 7301 working face of the Zhaolou coal mine, this paper studies the evolution of stress and energy when the working face passed through the area affected by pillars. The adopted methods include numerical simulations and field monitoring. The change in stress concentration factor and stress gradient because of the mining activities in lower coal seam was analyzed by numerical simulation, indicating that the stress gradient reaches a peak when the working face is closed to the area under the edge and junction of pillars, which has the high risk of inducing rockburst. The sources’ location, variation rule of microseismic (MS) total energy and events, frequency spectrum distributions, and source parameters are discussed, respectively, based on the field monitoring data. The main conclusions were obtained as follows: (1) The total energy and event counts reach the peak when working face is close to the area under the edge and the junction of pillars. (2) The dominant frequency transfers from high frequency to low frequency, the stress drop reaches the peak value, the energy index decreases sharply, and the cumulative apparent volume increases sharply, which all are obvious precursory characteristics before rockburst.
Effect of Different Modified Atmosphere Packaging on the Quality of Mulberry Fruit (Morus alba L. cv Kokuso 21)
Authors: Tinebra Ilenia , Sortino Giuseppe , Inglese Paolo , Fretto Silvia , Farina Vittorio
Published: February 2021

The control of temperature and gas composition is essential to maintain the fresh flavor and quality of perishable fruits like mulberry. This study presented a modified atmosphere experiment (MAP) for fresh fruit showing the potential benefits of innovative gas mixing with argon. The effects of MAP were studied on the physicochemical and qualitative attributes of mulberry preserved at4±1°C and90±5%R.H. Fresh mulberries were packaged with different gas combinations: MAP1 (4%O2+6%CO2+90%N2), MAP2 (10%O2+5%CO2+85%Ar), CTR1 (20.9%O2+0.04%CO2), and CTR2 (10%O2+5%CO2+85%N2). Changes in quality parameters were evaluated after 0, 4, 8, and 12 days of storage. Mulberries packaged with MAP had a lower weight loss than CTR samples which lost more than 80% of their initial weight. Furthermore, the results showed that the argon treatment was the best in keeping the fruit juice content, preserving its structure. Despite not showing great differences with MAP1 treatment, Ar allowed to maintain high TSS up to 8 storage days, slowed CO2 production. The sensory profile of mulberry fruit was not significantly affected by storage in modified atmospheres, and the production of potential unpleasant odors in MAP2 could not be perceived. The results of this study confirm that this innovative approach, using MAP technology, has a potential use in maintaining mulberry fruit quality for a longer time.