bluuebunny/crossref_metadata_2025 huggingface dataset:
Hearing status in vitamin B12‐deficient children
Authors: Akyay Arzu , Soylu Erkan , Ünsal Selim , Demirol Hatice , Bahçeci Semiha
Published: February 2021

Aim

The aim of this study is to investigate the effects of vitamin B12 deficiency on hearing in school‐aged children by pure‐tone audiometry.

Methods

Forty‐three vitamin B12‐deficient children and 37 age‐matched control subjects were enrolled in the study. Tympanometric evaluations and pure‐tone audiometry including high frequencies were performed on the subjects. The results were compared between the two groups.

Results

Both right and left ear pure‐tone hearing thresholds (PTHTs) at 0.25–4 kHz, and four‐frequency pure‐tone average values were significantly better in the control group compared with the patient group (P < 0.05). However, PTHTs at 8–16 kHz were not different between the two groups (P > 0.05). Vitamin B12 level also did not show any significant correlation with the PTHTs at 0.25–16 kHz (P > 0.05).

Conclusion

This study indicates that vitamin B12 deficiency may contribute to hearing impairment at low frequencies as a possible aetiological factor in children.
Meat goat diet supplementation with crude glycerine: Ruminal fermentation metabolism, blood chemistry profile, animal performance and carcass traits
Authors: Gurung Nar K. , Tuoho Kweku B. , Abrahamsen Frank W. , Min Byeng R.
Published: February 2021

The objective of this experiment was to determine the effects of feeding varying levels of crude glycerine (CG) on dry matter intake (DMI), animal performance, carcass traits and rumen volatile fatty acids (VFA) concentration in meat goats. Twenty‐four intact male Boer goats (23.9 ± 1.0 kg initial BW and 4–5 months of age) were randomly assigned to one of four experimental diets (n = 6) containing 30% bermudagrass hay plus 70% concentrate mix with 0, 5, 10 or 15% CG in the diet on an as‐fed basis, substituted for the corn portion of the concentrate. Feed offered and refusals were monitored daily for 84 days. Goats were weighed at 28‐days interval. Blood and rumen samples were collected on day 84. At the end of the 84‐days feeding period, goats were harvested, and carcass characteristics measured. Feed intake, average daily gain (ADG), gain‐to‐feed ratio (G:F), carcass traits and VFA concentrations were analysed as a completely randomized design. The CG did not influence animal body weight (BW) changes, ADG and G:F ratio but tended to (p = 0.06) decrease DMI. Molar per cent propionic acid increased linearly (p < 0.05) with increasing CG. The acetate: propionate (A:P) ratio decreased (p < 0.05) with increasing amounts of CG in the diet. The CG addition tended to increase (p = 0.09) the longissimus muscle (LM area) in meat goats. In conclusion, CG can replace corn in diet for growing meat goats when fed up to 15% of diet, improving ruminal propionate concentration, but decreasing A:P ratio without affecting animal performance and carcass traits.
ACVIM consensus statement on pancreatitis in cats
Authors: Forman Marnin A. , Steiner Joerg M. , Armstrong P. Jane , Camus Melinda S. , Gaschen Lorrie , Hill Steve L. , Mansfield Caroline S. , Steiger Katja
Published: February 2021

Background

Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges.

Objective

To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field.

Animals

None.

Methods

A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations.

Results

There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats.

Conclusions and Clinical Importance

Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.
A natural laboratory to elucidate the evolution of endogenous‐exogenous retroviral interactions
Authors: Chiu Elliott S. , Gagne Roderick B.
Published: February 2021

The advent of whole genome sequencing has revealed much about the genomes of animals including the relatively large percentage of the genome consisting of endogenous retroviruses (ERV; International Human Genome Sequencing Consortium, 2001). An ERV arises when a retrovirus integrates into a host germ cell genome through normal infection processes. Germline infections can be transmitted to offspring through Mendelian inheritance and at times become fixed elements of the host genome (Weiss, 2006). At their inception, these endogenized retroviruses maintain all the functions of their exogenous progenitors and can produce infectious virus (Figure 1). Mutations in the ERV randomly accumulate over time and can lead to the loss of the deleterious effects. In addition, the ERV can provide benefits to the host often via limiting exogenous viral infections (Chiu and VandeWoude, 2020a). However, most of these endogenous viruses are evolutionary relics representing historical infections and have no contemporary exogenous virus. This limits the opportunities to understand the evolution of ERVs and their interactions with exogenous viruses. In this issue of Molecular Ecology, Quigley et al. (2020) use a novel approach to show that koala retrovirus (KoRV) is undergoing endogenization along a geographic gradient with a variety of exogenous variants dispersed across the landscape. This system provides an opportunity to further elucidate the complex mechanisms in which endogenous and exogenous viruses interact and follow the evolution of an ERV in real time.
What, After All, Is the Work of Culture?
Authors: Colapietro Vincent
Published: February 2021

This paper offers an overview of Joseph Margolis’s philosophy of culture, highlighting how Margolis’s radical historicism is not inconsistent with our realistic intuitions regrading facts and objectivity. While Margolis identifies interpretation as the work of culture, the paper suggests that a much more basic sense of human labor needs to be thematized more fully than Margolis does in any defensible account of culture. Margolis of course appreciates work in this sense, but he does not consistently make it integral to his conception of culture. Even so, what he so forcefully defends is, as one commentator has put it, “beautiful. It’s also erudite, elegant, and insightful (and frightfully, dialectically intricate).”
Pixel‐level multicategory detection of visible seismic damage of reinforced concrete components
Authors: Miao Zenghui , Ji Xiaodong , Okazaki Taichiro , Takahashi Noriyuki
Published: February 2021

The detection of visible damage (i.e., cracking, concrete spalling and crushing, reinforcement exposure, buckling and fracture) plays a key role in postearthquake safety assessment of reinforced concrete (RC) building structures. In this study, a novel approach based on computer‐vision techniques was developed for pixel‐level multicategory detection of visible seismic damage of RC components. A semantic segmentation database was constructed from test photos of RC structural components. Series of datasets were generated from the constructed database by applying image transformations and data‐balancing techniques at the sample and pixel levels. A deep convolutional network architecture was designed for pixel‐level detection of visible damage. Two sets of parameters were optimized separately, one to detect cracks and the other to detect all other types of damage. A postprocessing technique for crack detection was developed to refine crack boundaries, and thus improve the accuracy of crack characterization. Finally, the proposed vision‐based approach was applied to test photos of a beam‐to‐wall joint specimen. The results demonstrate the accuracy of the vision‐based approach to detect damage, and its high potential to estimate seismic damage states of RC components.
Toward incorporating epigenetics into regulation of gene expression in the parasite Trichomonasvaginalis
Authors: Lizarraga Ayelen , Muñoz Daniela , Strobl‐Mazzulla Pablo H. , de Miguel Natalia
Published: February 2021

Trichomonas vaginalis is an extracellular parasite that colonizes the human urogenital tract, causing a highly prevalent sexually transmitted infection. The parasite must change its transcriptional profile in order to establish and maintain infection. However, few core regulatory elements and transcription factors have been identified to date and little is known about other mechanisms that may control these rapid changes in gene expression during parasite infection. In the last years, epigenetic mechanisms involved in the regulation of gene expression have been gaining major attention in this parasite. In this review, we summarize and discuss the major advances of the last few years with regard to epigenetics (DNA methylation, post‐translational histone modifications, and histone variants) in the parasite T. vaginalis. These studies can shed light into our current understanding of this parasite's biology with far‐reaching implications for the prognosis and treatment of trichomoniasis.
Impact of the combined use of intracardiac ultrasound and a steerable sheath visualized by a 3D mapping system on pulmonary vein isolation
Authors: Wakamatsu Yuji , Nagashima Koichi , Kurokawa Sayaka , Otsuka Naoto , Hayashida Satoshi , Yagyu Seina , Hirata Shu , Ohkubo Kimie , Nakai Toshiko , Okumura Yasuo
Published: February 2021

Background

A novel steerable sheath visualized on a three‐dimensional mapping system has become available in this era in which a durable pulmonary vein (PV) isolation (PVI) with reduced fluoroscopy is required.

Methods

In 60 patients who underwent a PVI with a visualized sheath (n = 30) and non‐visualized conventional sheath (n = 30), the fluoroscopic time and catheter stability during the PVI were analyzed.

Results

The fluoroscopic time during the transseptal access (0 [0, 0.1] vs. 1.4 [0.8, 2.3] minutes, P < .001) and PVI (0 [0, 0.1] vs. 0.4 [0.2, 1.1] minutes, P < .001) were shorter in the visualized sheath group than conventional sheath group. The procedure time during the PVI (32.0 [26.8, 36.3] vs. 41.0 [31.8, 47.3] minutes, P = .01), particularly during the right PVI (15.0 [12.8, 18.0] vs. 23.0 [15.8, 26.3] minutes, P = .009), was shorter in the visualized sheath group than conventional sheath group, however, that during the other steps was equivalent. The standard deviation of the catheter contact force during each radiofrequency application was smaller in the visualized sheath group than conventional sheath group (4.5 ± 2.7 vs. 4.9 ± 3.1 g, P = .001). The impedance drop for each lesion was larger in the visualized sheath group than conventional sheath group (10.7 ± 6.5 vs. 9.8 ± 5.5 ohms, P < .001). The incidence of acute PV reconnections per patient (30% vs. 23%, P = .56) and per PV segment (2.5% vs. 2.3%, P = .83) were similar between the two groups. No major complications occurred in either sheath group.

Conclusions

The use of visualized sheaths may reduce the fluoroscopic time and improve the catheter stability during the PVI.
Data integration for the numerical simulation of cardiac electrophysiology
Authors: Pagani Stefano , Dede’ Luca , Manzoni Andrea , Quarteroni Alfio
Published: February 2021

The increasing availability of extensive and accurate clinical data is rapidly shaping cardiovascular care by improving the understanding of physiological and pathological mechanisms of the cardiovascular system and opening new frontiers in designing therapies and interventions. In this direction, mathematical and numerical models provide a complementary relevant tool, able not only to reproduce patient‐specific clinical indicators but also to predict and explore unseen scenarios. With this goal, clinical data are processed and provided as inputs to the mathematical model, which quantitatively describes the physical processes that occur in the cardiac tissue. In this paper, the process of integration of clinical data and mathematical models is discussed. Some challenges and contributions in the field of cardiac electrophysiology are reported.
Associations between Environmental dust composition and Atopic Dermatitis in urban and rural settings
Authors: Trikamjee Thulja , Basera Wisdom , Botha Maresa , Facey‐Thomas Heidi E. , Gaunt Ben , Genuneit Jon , Gray Claudia L. , Hadebe Sabelo , Hlela Carol , Kirstein Frank , Lunjani Nonhlanhla , Mankahla Avumile , Ramjith Jordache , Levin Michael
Published: February 2021

Background

Environmental exposures are involved in the pathogenesis of the allergic phenotype and in determining which individual triggers a person becomes sensitized to. Atopic dermatitis (AD) may modulate these effects through increased penetration through the skin modifying the immune system and AD may be triggered or intensified by environmental exposures. These exposures and immune‐modulating factors may differ in urban and rural environments.

Objectives

To compare house dust composition in urban and rural settings and correlate them with AD outcomes.

Methods

Dust samples were collected from the beds of 156 children aged 6 months to 3 years. 42% of participants had atopic dermatitis. Samples were analyzed for bacterial endotoxin, fungal (β‐1,3‐glucan) levels, and house dust mite, cockroach, dog, cat, mouse, and peanut allergen. Exposures were compared in urban and rural environments and in participants with and without AD.

Results

Endotoxin but not fungal β‐glucan exposure is higher in the environment of healthy controls than children with AD in both urban and rural settings. House dust mite allergen exposure is high in urban and rural settings with Dermatophagoides detected in 100% of samples. Cat and dog allergen exposure mirrors pet ownership patterns which differ slightly between groups and environments. Mouse allergen exposure is higher in urban homes.

Conclusion

Environmental endotoxin may be protective against AD in both urban and rural settings. There are marked differences in allergen exposure in urban and rural settings, but these are unlikely to be important protective or risk factors.
Testing the predictive and theoretical validity of the network uncertainty measure
Authors: Stein James B.
Published: February 2021

The present study explores the network uncertainty measure (NUM) as a longitudinal determinant of both relational uncertainty and biased cognitions (the perception that relational talk is threatening) at a later time. Using relational turbulence theory (RTT) as a framework, the NUM was tested for predictive and theoretical validity. Results indicated that network uncertainty at time 1 predicted self and partner, and relationship uncertainty at time 2 with varying strength of relationships. Moreover, the NUM predicted biased cognitions at time 2 when controlling for self, partner, and relationship uncertainty. Efforts were made to see if relational uncertainty mediates the relationship between network uncertainty and biased cognitions. Those results were nonsignificant. These clarify the nature of uncertainties both within and outside of close relationships. Implications are discussed in terms of both theoretical and conceptual development.
Reasons for resentment of high school teenagers with friends
Authors: Öztürk Nilgün , Atli Abdullah
Published: February 2021

The purpose of this qualitative study was to examine the reasons for resentment of high school teenagers of their friends, and to categorize these reasons under overarching themes. As a result of the thematic analyses of the qualitative conversations made with 90 (45 = girls, 45 = boys) high school students aged 15–18, the reasons for resentment were collected under the following five main themes: “Jealousy,” “Gossiping and sharing secrets,” “Disagreement on common events,” “Falling in love with my friend's boyfriend/girlfriend” and “Pranks.” We believe that this study provides data in contributing to the in‐depth understanding of the feelings and experiences of resentful teenagers who have problems in friendships.
Drought tolerance inBrassica napusis accompanied with enhanced antioxidative protection, photosynthetic and hormonal regulation at seedling stage
Authors: Ayyaz Ahsan , Miao Yilin , Hannan Fakhir , Islam Faisal , Zhang Kangni , Xu Jianxiang , Farooq Muhammad Ahsan , Zhou Weijun
Published: February 2021

Climate change, food insecurity, water scarcity, and population growth are some of today's world's frightening problems. Drought stress exerts a constant threat to field crops and is often seen as a major constraint on global agricultural productivity; its intensity and frequency are expected to increase in the near future. The present study investigated the effects of drought stress (15% w/v polyethylene glycol PEG‐6000) on physiological and biochemical changes in fiveBrassica napuscultivars (ZD630, ZD622, ZD619, GY605, and ZS11). For drought stress induction, 3‐week‐old rapeseed oil seedlings were treated with PEG‐6000 in full strength Hoagland nutrient solution for 7 days. PEG treatment significantly decreased the plant growth and photosynthetic efficiency, including primary photochemistry (Fv/Fm) of PSII, intercellular CO2, net photosynthesis, chlorophyll contents, and water‐use efficiency of all studiedB. napuscultivars; however, pronounced growth retardations were observed in cultivar GY605. Drought‐stressedB. napuscultivars also experienced a sharp rise in H2O2generation and malondialdehyde (MDA) content. Additionally, the accumulation of ROS was accompanied by increased activity of enzymatic antioxidants (superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase), although the increase was more obvious in ZD622 and ZS11. Drought stress also caused an increased endogenous hormonal biosynthesis (abscisic acid, jasmonic acid, salicylic acid) and accumulation of total soluble proteins and proline content, but the extent varies inB. napuscultivars. These results suggest thatB. napuscultivars have an efficient drought stress tolerance mechanism, as shown by improved antioxidant enzyme activities, photosynthetic and hormonal regulation.
Survival and sexual maturity of sexually propagated Acropora verweyi corals 4 years after outplantation
Authors: Ligson Charlon A. , Cabaitan Patrick C.
Published: February 2021

Most coral reef restoration efforts are carried out over 1–2 years, and few have assessed long‐term (over 3 years) outcomes. Although studies of outplantation of sexually propagated corals have reported promising initial results, few studies have followed outplanted corals to maturity. Here, we monitored sexually propagated Acropora verweyi corals for 4 years post‐outplantation to determine their survival and sexual maturity. These corals were outplanted when 4 months old in two size classes (small = 0.3–0.5 cm; large = 1.0–1.5 cm) at two sites in the northwestern Philippines. Four years after outplantation, the 240 colonies of A. verweyi exhibited 17.9% survival, with mean diameters ranging from 7.48–26.8 cm. Most of the surviving outplants were gravid (81.4% of the 43 colonies) with mean diameters of at least 11.8 cm. Higher survivorship was detected in the initial large size class outplants than in the small ones at the natal site, but not at the other site. However, 4 years after outplantation, there was no significant difference in terms of geometric mean diameter between the initial size classes or between the sites. Results show that 4‐month‐old outplants of sexually propagated corals can survive until sexual maturity and are already capable of contributing gametes for the potential recovery of degraded coral communities at age 4 years.
Zooplankton functional diversity as an indicator of a long‐term aquatic restoration in an Amazonian lake
Authors: Josué Iollanda I. P. , Sodré Elder O. , Setubal Rayanne B. , Cardoso Simone J. , Roland Fabio , Figueiredo‐Barros Marcos P. , Bozelli Reinaldo L.
Published: February 2021

Mining is an important economic activity that can have severe impacts on aquatic ecosystems. Plankton communities are commonly used as bioindicators of human‐related threats to freshwater environments due to their rapid response to environmental conditions changes. Here, we used zooplankton functional diversity to understand the recovery patterns of an Amazonian lake impacted by mining activity (input of bauxite tailings) after 30 years of natural attenuation and active restoration processes. Zooplankton species richness and functional diversity (Rao's quadratic entropy—FDQ and community‐level weighted means of trait values—CWM) were compared in impacted and reference areas during the flood period, in March 2015. We found a significant negative influence of turbidity on zooplankton FDQ, and similar FDQ and CWM values between the active restoration area and the reference area. These results suggest a positive effect of vegetation restoration efforts for the zooplankton community of Batata Lake. We demonstrated the utility of zooplankton functional diversity metrics as bioindicators of freshwater restoration, the response of the aquatic ecosystem to vegetation restoration and, consequently, water quality.
Health and Economic Outcomes Associated with Polio Vaccine Policy Options: 2019–2029
Authors: Kalkowska Dominika A. , Thompson Kimberly M.
Published: February 2021

The polio endgame remains complicated, with many questions about future polio vaccines and national immunization policies. We simulated possible future poliovirus vaccine routine immunization policies for countries stratified by World Bank Income Levels and estimated the expected costs and cases using an updated integrated dynamic poliovirus transmission, stochastic risk, and economic model. We consider two reference cases scenarios: one that achieves the eradication of all wild polioviruses (WPVs) by 2023 and one in which serotype 1 WPV (WPV1) transmission continues. The results show that the addition of inactivated poliovirus vaccine (IPV) to routine immunization in all countries substantially increased the expected costs of the polio endgame, without substantially increasing its expected health or economic benefits. Adding a second dose of IPV to the routine immunization schedules of countries that currently include a single IPV dose further increases costs and does not appear economically justified in the reference case that does not stop WPV transmission. For the reference case that includes all WPV eradication, adding a second IPV dose at the time of successful oral poliovirus vaccine (OPV) cessation represents a cost‐effective option. The risks and costs of needing to restart OPV use change the economics of the polio endgame, although the time horizon used for modeling impacts the overall economic results. National health leaders will want to consider the expected health and economic net benefits of their national polio vaccine strategies recognizing that preferred strategies may differ.
Interpretation of contextual influences with explanatory tools: Travel mode likelihood mapping using GPS trajectories
Authors: Lee Kangjae , Kwan Mei‐Po
Published: February 2021

Past studies have failed to address the spatially and temporally varying impacts of environmental factors regarding the uncertain geographic context problem. This study seeks to provide an innovative framework to facilitate the understanding of spatially and temporally varying impacts of multiple contexts on individuals' travel modes using GIS and machine learning techniques. It adopts machine learning techniques to create likelihood maps to predict the spatiotemporal patterns of individual travel behaviors and uses explanatory tools to explore the spatially and temporally varying impacts. The most notable change at a local level in the spatial dimension was that assaults and offenses involving children turned out to be important in two selected communities in Chicago. Regarding the temporally varying impact, batteries, other offenses, and robberies showed negative associations with the walking prediction to some extent at the afternoon peak (5–7:59 p.m.) during weekdays. The proposed approach will enable meaningful interpretation of complex interactions between multiple environmental factors and individual travel behaviors to suggest policies in urban planning and design.
LcERF2 modulates cell wall metabolism by directly targeting a UDP‐glucose‐4‐epimerase gene to regulate pedicel development and fruit abscission of litchi
Authors: Yi Jun‐Wen , Wang Yi , Ma Xiao‐Sha , Zhang Jie‐Qiong , Zhao Ming‐Lei , Huang Xu‐Ming , Li Jian‐Guo , Hu Gui‐Bing , Wang Hui‐Cong
Published: February 2021

Elucidating the biochemical and molecular basis of premature abscission in fruit crops should help develop strategies to enhance fruit set and yield. Here, we report that LcERF2 contributes to differential abscission rates and responses to ethylene in Litchi chinensis (litchi). Reduced LcERF2 expression in litchi was observed to reduce fruit abscission, concurrent with enhanced pedicel growth and increased levels of hexoses, particularly galactose, as well as pectin abundance in the cell wall. Ecoptic expression of LcERF2 in Arabidopsis thaliana caused enhanced petal abscission, together with retarded plant growth and reduced pedicel galactose and pectin contents. Transcriptome analysis indicated that LcERF2 modulates the expression of genes involved in cell wall modification. Yeast one‐hybrid, dual‐luciferase reporter and electrophoretic mobility shift assays all demonstrated that a UDP‐glucose‐4‐epimerase gene (LcUGE) was the direct downstream target of LcERF2. This result was further supported by a significant reduction in the expression of the A. thaliana homolog AtUGE2‐4 in response to LcERF2 overexpression. Significantly reduced pedicel diameter and enhanced litchi fruit abscission were observed in response to LcUGE silencing. We conclude that LcERF2 mediates fruit abscission by orchestrating cell wall metabolism, and thus pedicel growth, in part by repressing the expression of LcUGE.
NOL‐mediated functional stay‐green traits in perennial ryegrass (Lolium perenne L.) involving multifaceted molecular factors and metabolic pathways regulating leaf senescence
Authors: Yu Guohui , Xie Zheni , Zhang Jing , Lei Shanshan , Lin Wenjing , Xu Bin , Huang Bingru
Published: February 2021

Loss of chlorophyll (Chl) is a hallmark of leaf senescence, which may be regulated by Chl catabolic genes, including NON‐YELLOW COLORING 1 (NYC1)‐like (NOL). The objective of this study was to determine molecular factors and metabolic pathways underlying NOL regulation of leaf senescence in perennial grass species. LpNOL was cloned from perennial ryegrass (Lolium perenne L.) and found to be highly expressed in senescent leaves. Transient overexpression of LpNOL accelerated leaf senescence and Chl b degradation in Nicotiana benthamiana. LpNOL RNA interference (NOLi) in perennial ryegrass not only significantly blocked Chl degradation in senescent leaves, but also delayed initiation and progression of leaf senescence. This study found that NOL, in addition to functioning as a Chl b reductase, could enact the functional stay‐green phenotype in perennial grass species, as manifested by increased photosynthetic activities in NOLi plants. Comparative transcriptomic analysis revealed that NOL‐mediated functional stay‐green in perennial ryegrass was mainly achieved through the modulation of Chl catabolism, light harvesting for photosynthesis, photorespiration, cytochrome respiration, carbohydrate catabolism, oxidative detoxification, and abscisic acid biosynthesis and signaling pathways.
Using the flow regimes framework to de‐hierarchise the analysis of commercial movements: Case studies from the Central African Copperbelt
Authors: Blaszkiewicz Hélène
Published: February 2021

Observing trade flows at a Southern African border reveals that different commodities move differently, raising the question of why some commodities stop when others flow, and why some flows move faster when others experience speed reductions and stoppages. This paper is concerned with presenting a theoretical framework – the flow regime framework – to make sense of the uneven rhythms and manners of the flow of commodities. Building on a review of four economic geography trends (transport geography, logistics studies, thing‐following studies, and scalar analysis) and of the orderings and dichotomies they create, I argue that we need a non‐hierarchical way to understand the complexity and variability of trade flows and traders’ strategies along different paces and rhythms. The flow regimes, defined as lasting socio‐technical agencements of practices, actors, infrastructure uses, and ideologies, comprise the proposed theoretical solution to make sense of the variability of commodities’ paces. This theoretical framework is illustrated empirically through the examples of the three flow regimes identified in the Central African Copperbelt, based on 11 months of ethnographic fieldwork: the off‐road regime, characterised by modular and flexible rhythms; the spare‐wheel regime, whose flows are subjected to state‐induced accelerations and stoppages; and the power‐steering regime, based on costly public and private technologies allowing for fast and fluid commercial movements. Without attempting to describe a particular scale of action, the concept of regimes makes it possible to analyse head‐on activities that are usually studied separately (such as “small” border trade and flows driven by large logistics firms). I conclude by suggesting that the flow regimes framework allows to highlight how the globalisation of flows features irregularity and lumpiness.
Pandemic trade: COVID‐19, remote work and global value chains
Authors: Espitia Alvaro , Mattoo Aaditya , Rocha Nadia , Ruta Michele , Winkler Deborah
Published: February 2021

This paper studies the trade effects of COVID‐19 using monthly disaggregated trade data for 28 countries and multiple trading partners from the beginning of the pandemic to June 2020. Regression results based on a sector‐level gravity model show that the negative trade effects induced by COVID‐19 shocks varied widely across sectors. Sectors more amenable to remote work contracted less throughout the pandemic. Importantly, participation in global value chains increased traders’ vulnerability to shocks suffered by trading partners, but it also reduced their vulnerability to domestic shocks.
COVID‐19, public procurement regimes and trade policy
Authors: Hoekman Bernard , Shingal Anirudh , Eknath Varun , Ereshchenko Viktoriya
Published: February 2021

This paper analyses a prominent dimension of the initial policy response to the COVID‐19 pandemic observed in many countries: the imposition of export restrictions and actions to facilitate imports. Using weekly data on the use of trade policy instruments during the first seven months of the COVID‐19 pandemic (January–July, 2020), we assess the relationship between the use of trade policy instruments and attributes of pre‐crisis public procurement regulation. Controlling for country size, government effectiveness and economic factors, we find that use of export restrictions targeting medical products is strongly positively correlated with the total number of steps and average time required to complete procurement processes in the pre‐crisis period. Membership of trade agreements encompassing public procurement disciplines is associated with actions to facilitate trade in medical products. These findings suggest future empirical assessments of the drivers of trade policy during the pandemic should consider public procurement systems.
The effect of autologous repair and voluntary wheel running on force recovery in a rat model of volumetric muscle loss
Authors: Washington Tyrone A. , Perry Richard A. , Kim John T. , Haynie Wesley S. , Greene Nicholas P. , Wolchok Jeffrey C.
Published: February 2021

New Findings

What is the central question of this study?

Following large traumatic loss of muscle tissue (volumetric muscle loss; VML), permanent functional and cosmetic deficits present themselves and regenerative therapies alone have not been able to generate a robust regenerative response: how does the addition of rehabilitative therapies affects the regenerative response?

What is the main finding and its importance?

Using exercise along with autologous muscle repair, we demonstrated accelerated muscle force recovery response post‐VML. The accentuated force recovery 2 weeks post‐VML would allow patients to return home sooner than allowed with current therapies.

Skeletal muscle can regenerate from damage but is overwhelmed with extreme tissue loss, known as volumetric muscle loss (VML). Patients suffering from VML do not fully recover force output in the affected limb. Recent studies show that replacement tissue (i.e., autograph) into the VML defect site plus physical activity show promise for optimizing force recovery post‐VML. The purpose of this study was to measure the effects of autologous repair and voluntary wheel running on force recovery post‐VML. Thirty‐two male Sprague–Dawley rats had 20% of their left tibialis anterior (LTA) excised then replaced and sutured into the intact muscle (autologous repair). The right tibialis anterior (RTA) acted as the contralateral control. Sixteen rats were given free access to a running wheel (Wheel) whereas the other 16 remained in a cage with the running wheel locked (Sed). At 2 and 8 weeks post‐VML, the LTA underwent force testing; then the muscle was removed and morphological and gene expression analysis was conducted. At 2 weeks post‐injury, normalized LTA force was 58% greater in the Wheel group compared to the Sed group. At 8 weeks post‐VML, LTA force was similar between the Wheel and Sed groups but was still lower than the uninjured RTA. Gene expression analysis at 2 weeks post‐VML showed the wheel groups had lower mRNA content of interleukin (IL)‐1β, IL‐6 and tumour necrosis factor α compared to the Sed group. Overall, voluntary wheel running promoted early force recovery, but was not sufficient to fully restore force. The accentuated early force recovery is possibly due to a more pro‐regenerative microenvironment.
Impact of resveratrol‐mediated increase in uterine artery blood flow on fetal haemodynamics, blood pressure and oxygenation in sheep
Authors: Aujla Tanroop , Darby Jack R. T. , Saini Brahmdeep S. , Lock Mitchell C. , Holman Stacey L. , Bradshaw Emma L. , Perumal Sunthara R. , McInnes Steven J. P. , Voelcker Nicolas H. , Wiese Michael D. , Macgowan Christopher K. , Seed Mike , Morrison Janna L.
Published: February 2021

New Findings

What is the central question of this study?

Uterine artery blood flow helps to maintain fetal oxygen and nutrient delivery. We investigated the effects of increased uterine artery blood flow mediated by resveratrol on fetal growth, haemodynamics, blood pressure regulation and oxygenation in pregnant sheep.

What is the main finding and its importance?

Fetuses from resveratrol‐treated ewes were significantly larger and exhibited a haemodynamic profile that might promote peripheral growth. Absolute uterine artery blood flow was positively correlated with umbilical vein oxygen saturation, absolute fetal oxygen delivery and fetal growth. Increasing uterine artery blood flow with compounds such as resveratrol might have clinical significance for pregnancy conditions in which fetal growth and oxygenation are compromised.

High placental vascular resistance hinders uterine artery (UtA) blood flow and fetal substrate delivery. In the same group of animals as the present study, we have previously shown that resveratrol (RSV) increases UtA blood flow, fetal weight and oxygenation in an ovine model of human pregnancy. However, the mechanisms behind changes in growth and the effects of increases in UtA blood flow on fetal circulatory physiology have yet to be investigated. Twin‐bearing ewes received s.c. vehicle (VEH, n = 5) or RSV (n = 6) delivery systems at 113 days of gestation (term = 150 days). Magnetic resonance imaging was performed at 123−124 days to quantify fetal volume, blood flow and oxygen saturation of major fetal vessels. At 128 days, i.v. infusions of sodium nitroprusside and phenylephrine were administered to study the vascular tone of the fetal descending aorta. Maternal RSV increased fetal body volume (P = 0.0075) and weight (P = 0.0358), with no change in brain volume or brain weight. There was a positive relationship between absolute UtA blood flow and umbilical vein oxygen saturation, absolute fetal oxygen delivery and combined fetal twin volume (all P ≤ 0.05). There were no differences between groups in fetal haemodynamics or blood pressure regulation except for higher blood flow to the lower body in RSV fetuses (P = 0.0170). The observed increase in fetal weight might be helpful in pregnancy conditions in which fetal growth and oxygen delivery are compromised. Further preclinical investigations on the mechanism(s) accounting for these changes and the potential to improve growth in complicated pregnancies are warranted.
Immobilisation induces sizeable and sustained reductions in forearm glucose uptake in just 24 h but does not change lipid uptake in healthy men
Authors: Burns Aisling M. , Nixon Aline , Mallinson Joanne , Cordon Sally M. , Stephens Francis B. , Greenhaff Paul L.
Published: February 2021

Key points

The trajectory, magnitude and localisation of metabolic perturbations caused by immobilisation (IMM) are unresolved.

Forearm glucose uptake (FGU) in response to glucose feeding was determined in healthy men before and during 72 h of forearm IMM, and the same measurements were made in the non‐IMM contralateral limb at baseline and 72 h. In a similar study design, FGU and forearm lipid uptake were determined after a high fat mixed‐meal (HFMM) in IMM and non‐IMM limbs.

FGU was reduced by 38%, 57% and 46% following 24, 48 and 72 h IMM, respectively, but was unchanged in the non‐IMM limb. A similar FGU response to IMM was observed after a HFMM, and forearm lipid uptake was unchanged.

A sizeable reduction in FGU occurs in just 24 h of IMM, which is sustained thereafter and specific to the IMM limb, making unloading per se the likely rapid driver of dysregulation.

The trajectory and magnitude of metabolic perturbations caused by muscle disuse are unknown yet central to understanding the mechanistic basis of immobilisation‐associated metabolic dysregulation. To address this gap, forearm glucose uptake (FGU) was determined in 10 healthy men (age 24.9 ± 0.6 years, weight 71.9 ± 2.6 kg, BMI 22.6 ± 0.6 kg/m2) during a 180 min oral glucose challenge before (0) and after 24, 48 and 72 h of arm immobilisation, and before and after 72 h in the contralateral non‐immobilised arm (Study A). FGU was decreased from baseline at 24 h (38%, P = 0.04), 48 h (57%, P = 0.01) and 72 h (46%, P = 0.06) of immobilisation, and was also 63% less than the non‐immobilised limb at 72 h (P = 0.002). In a second study, FGU and forearm lipid uptake were determined in nine healthy men (age 22.4 ± 1.3 years, weight 71.4 ± 2.8 kg, BMI 22.6 ± 0.8 kg/m2) during a 420 min mixed‐meal challenge before (0) and after 24 and 48 h of arm immobilisation and before and after 72 h in the contralateral non‐immobilised arm (Study B). FGU responses were similar to Study A, and forearm lipid uptake was unchanged from pre‐immobilisation in both arms over the study. A sizeable decrement in FGU in response to glucose feeding occurred within 24 h of immobilisation that was sustained and specific to the immobilised limb. Increasing lipid availability had no additional impact on the rate or magnitude of these responses or on lipid uptake. These findings highlight a lack of muscle contraction per se as a fast‐acting physiological insult to FGU.
An Open Architecture Framework for the Integration of Virtual Prototyping Software Tools
Authors: Jayaram Uma , Jayaram Sankar , Tilton Donald , Seaney Kevin
Published: February 2021

The use of virtual prototyping tools typically results in products with lower costs, better quality, and shorter development cycles. However, there are many interface/configuration problems that occur in the process of obtaining a design solution using the typical gamut of virtual prototyping tools. This paper presents the architecture, design, and implementation of a framework to support the integration of the multiple software systems used in the virtual prototyping of mechanical components. Some of the virtual prototyping software systems considered in the implementation of this framework were customer input systems, solid modeling systems, finite-element systems, knowledge-based systems, NC code generator systems, and virtual assembly systems. There is a pressing need for the different software systems to talk to each other while transferring the required data at varying levels of abstraction without compromising data integrity.

Of special significance is the fact that the philosophy of the framework is widely applicable to any mechanical system, and is almost independent of specific software utilities. Thus, this design incorporates a clear path towards expansion to encompass other independent tools/systems. The architecture was designed using object-oriented methods. The framework was very successfully demonstrated for a well-defined subset of software systems being used at Isothermal Systems Research (ISR) Inc., a leader in proprietary spray cooling systems for multi-chip modules. This framework effectively supports the strong industry push towards integrated design, manufacturing, and virtual prototyping. The work presented in this paper was supported by an SBIR grant from the Department of Commerce, DOC contract 50-DKNB-5-00117.
Toward an Automatic Method of Geometric Error Analysis
Authors: Cardew-Hall Michael , West Geoff A. W. , Rolfe Bernard
Published: February 2021

In this paper a method of determining geometric error components from a large amount of sensed (measured) data in line with a given tolerancing scheme is described. The approach is based on the deformation of a nominal CAD model to yield a deformation vector which quantifies the deviations in specified and constrained control parameters. The proposed advantages of this approach are that it allows analysis of measured data against a CAD model without relating specific data to set model features and that specific error modes are isolated in line with the tolerances applied to the CAD model.
Reconstruction of Sculptured Surface on Reverse Engineering
Authors: Wang Gou-Jen , Wang Chung-Chang
Published: February 2021

In this article, solutions for redundant measured data elimination and surface reconstruction on reverse engineering are presented. In redundant data elimination, we propose a simple algorithm that can efficiently discard those redundant measured points according to the required degree of accuracy. While in the surface reconstruction, we try first convert all eliminated column or row data into spline (B-Spline, Beizer and Cubic-Spline) curves. Methods for two dimensional spline (u, v directions) curve construction are described. Non-meshed two dimensional spline curves are then blended to a surface model by formatting data points into a sparse matrix data structure. Experimental results show that the proposed characteristic points extraction method can remarkably reduce the reconstruction time only on the cost of a little extracting time and minor modeling errors. Comparisons among B-spline, Beizer and Cubic-spline on data structure, computing time, and accuracy demonstrate that the B-spline algorithm is superior to other algorithms in surface reconstruction.
Vertical Partnering Implementation for Supplier Integration
Authors: Gardner Ann , Nugent Nancy , Fitzgerald Edward , Laford Thomas , Babish James
Published: February 2021

This paper will present an approach that takes the concept of vertical partnering first demonstrated under an AF ManTech pathfinder program and provides a plan for its commercial implementation. The vertical partnering concept provides small and medium-sized Enterprises (SME) secure access to Raytheon’s CAD / CAM software and engineering databases. The system is being extended from an X-based client / server technology to a World Wide Web (WWW) based system. This project establishes the first team of seven Raytheon suppliers using this system for actual product delivery. The Scranton Electronic Commerce Resource Center will provide the guidance and support necessary to make this approach available to all interested contractor / SME partnerships throughout the United States. It is anticipated that benefits will come from drastically reducing the time to move data from the procurement agencies to the subcontractors and from reducing the time it takes for the subcontractor to be able to assemble and comprehend data packages.
A Software Structure for JIT Supply Chain Production Synchronization System Using Internet and EDI
Authors: Yang Wensheng , Sarin Sanjiv
Published: February 2021

This paper presents a software structure for a fully computer integrated JIT Supply Chain Production Synchronization System using Internet and EDI technology. Forming a JIT supply chain makes the production scheduling activity much more complex because: (i) while a manufacturer is trying to synchronize its internal production activity, it needs to synchronize with the activities of external partners on the same chain as well; and (ii) under JIT, suppliers typically make smaller and more frequent deliveries, resulting in a significant increase in related business transactions and the variations of the inputs to the scheduling process is increased accordingly. This paper discusses why and how the application of Internet and EDI technology can improve the production synchronization of a JIT supply chain System. A software structure for system integration is also presented.
A Framework for Cooperating Engineering Knowledge Agents
Authors: Erickson Douglas M. , Brown Don R. , Hwang Kuo-Yen , Pan Yoong-Keong , Daga Anand
Published: February 2021

Computers offer many tools to aid the engineer in producing better designs. Some of these tools are expert systems that, historically, have been expensive to develop and difficult to market. Other tools are complex, general-purpose applications that require training and expertise to be correctly applied to specific problems. A framework which allows such tools to cooperate in a networked environment would eliminate duplication of programming effort and allow cheaper development of expert systems. Being available on the Internet also offers an attractive means of distributing the product to engineers who need it. This paper describes a framework that allows engineering software on the Internet to cooperate in order to solve a user’s problem.
Flashover: A Study of Parameter Effects on the Time to Reach Flashover Conditions
Authors: Kim Hyeong-Jin , Lilley David G.
Published: February 2021

Flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. The objective of the present contribution is to calculate the development of flashover in a typical single room fire, and show the effect of ten key parameters on the time required to reach flashover conditions. It is found that the major parameters affecting flashover are fire growth rate, ventilation opening area, and room area.