bluuebunny/crossref_metadata_2025 huggingface dataset:
How do species barriers decay? Concordance and local introgression in mosaic hybrid zones of mussels
Authors: Simon Alexis , Fraïsse Christelle , El Ayari Tahani , Liautard‐Haag Cathy , Strelkov Petr , Welch John J. , Bierne Nicolas
Published: October 2020

The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study ‘replicated’ instances of secondary contact between closely related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry‐informative panel of such SNPs. We then compared their frequencies in newly sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi‐stable variants (Dobzhansky‐Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact.
Do the ages of parents or helpers affect offspring fitness in a cooperatively breeding bird?
Authors: Cooper Eve B. , Bonnet Timothée , Osmond Helen , Cockburn Andrew , Kruuk Loeske E. B.
Published: October 2020

Age‐related changes in parental phenotypes or genotypes can impact offspring fitness, but separating germline from nongermline transgenerational effects of ageing is difficult for wild populations. Further, in cooperatively breeding species, in addition to parental ages, the age of ‘helpers’ attending offspring may also affect juvenile performance. Using a 30‐year study of a cooperative breeder with very high rates of extra‐pair paternity, the superb fairy‐wren (Malurus cyaneus), we investigated the effects of maternal, paternal and helper ages on three measures of offspring performance: nestling weight, juvenile survival to independence and recruitment to the breeding population. Mothers with a longer lifespan had offspring with higher juvenile survival, indicating selective disappearance, but the effect of maternal age on juvenile survival was of similar magnitude but negative. For extra‐pair offspring, there was no evidence of any effect of the ages of either the genetic sire or the cuckolded ‘social’ father. However, for within‐pair offspring, there was a positive effect of paternal age on juvenile survival, which we suggest may be driven by sexual selection. There were positive associations between the average age of helpers attending a nest and two of the three aspects of offspring performance; these effects were stronger than any of the effects of parental age. In general, the multiple associations between offspring fitness and the ages of adults around them appeared to be driven more by age‐related changes in environmental effects than by age‐related changes in the germline.
Genetic and morphological assessment of a vulnerable large catfish, Silonia silondia (Hamilton, 1822), in natural populations from India
Authors: Mandal Sangeeta , Singh Achal , Sah Priyanka , Singh Rajeev K. , Kumar Raj , Lal Kuldeep K. , Mohindra Vindhya
Published: October 2020

Silonia silondia is a commercially important fish distributed in Asian countries, which is under threat due to overexploitation. This study focuses on the morphological analysis and genetic variation of S. silondia individuals, through truss network and sequencing of two mitochondrial regions, respectively, from six wild populations of the Ganga and Mahanadi river systems in India. A total of 38 haplotypes was observed by analysing combined mitochondrial genes (cytochrome b + ATPase 6/8) in 247 individuals of S. silondia collected from six populations. Average haplotype and nucleotide diversities were 0.8508 and 0.00231, respectively. Genetic structure analysis showed the predominant cause of genetic variation to be within populations. The two clades were observed among the haplotypes and time of divergence from their most probable ancestor was estimated to be around 0.3949 mya. Analysis of combined mitochondrial genes in six populations of S. silondia resulted into three management units or genetic stocks. The truss network analysis was carried out by interconnecting 12 landmarks from digital images of specimens to identify phenotypic stocks. Sixty‐five truss morphometric variables were analysed for geometric shape variation which revealed morphological divergence in River Son specimens. The present study presents molecular markers and genetic diversity data which can be critical input for conservation and management of differentiated populations and future monitoring of the genetic bottleneck. The morphological shape analysis clearly shows that variation in the insertion of adipose fin is an important parameter influencing the morphological discrimination.
Heat and mass transport analysis of the drying of freshwater fishes by a forced convective air‐dryer
Authors: Khan M. Arif , Moradipour Mahsa , Obeidullah Md. , Quader A. K. M. Abdul
Published: October 2020

The drying behavior of different freshwater fishes (with/without scales) is investigated using a simple convective heated air dryer. Drying processes are analyzed to study the kinetics of drying, shrinkage dependent variable effective diffusivity, convective heat and mass transport, and the energy aspect of drying. Among the drying kinetic models, Hasibuan–Daud and Haghi–Angiz‐I models produce the best fit for fishes with scales and Hii model produces the best fit for fish without scales. Diffusion analysis performed based on simplified solution of Fick's diffusion equation shows higher effective diffusivity for fish without scales, proving additional barrier from scales (for fish with scales) that need to be considered during dryer design. Calculated instantaneous heat and mass transfer coefficients (different for fish with or without scales) also agree with this observation, accentuating the difference based on scales. Drying process for all fishes obeys the heat‐mass transfer correlation. Estimated parameters such as effective diffusivity (0.2–1 × 10−9 m2/s) and convective heat and mass transfer coefficients (7–14 W/m2/K and 2.8–4.5 × 10−6 m/s, respectively) can be utilized in designing different fish drying systems. Average and instantaneous total energy consumption, specific moisture extraction ratio, and specific energy consumption are evaluated in order to provide a comprehensive picture of the drying process.

Practical Applications

Fresh‐ and salt‐water fishes account for major sources of protein‐rich food for substantial parts of the population in underdeveloped and developing nations. To circumvent the wastage associated with microbial contaminations during prolific seasons, fish drying has been widely employed as a way of preserving this perishable food. Convective drying of agricultural products as well as marine foods is a commonly employed drying method for food preservation. This study investigates the drying behavior of three different freshwater fishes using an in‐house constructed forced convective air dryer. The experimental drying characteristics and estimated parameters by model fitting during fish drying will be particularly applicable in the wide field of fish drying. The outcome of this study can also be utilized for more effectively designing and evaluating low‐cost convective fish dryers.
Catechol‐O‐Methyltransferase Genotype, Frailty, and Gait Speed in a Biracial Cohort of Older Adults
Authors: Mance Shannon , Rosso Andrea , Bis Joshua , Studenski Stephanie , Bohnen Nico , Rosano Caterina
Published: October 2020

OBJECTIVE

To examine whether the association between dopamine‐related genotype and gait speed differs according to frailty status or race.

DESIGN

Cross‐sectional population‐based study (Cardiovascular Health Study).

SETTING

Multicenter study, four U.S. sites.

PARTICIPANTS

Volunteer community‐dwelling adults aged 65 years and older, without evidence of Parkinsonʼs disease (N = 3,744; 71 years; 82% White; 39% male).

MEASUREMENTS

Gait speed (usual pace; m/s), physical frailty (Fried definition), and genetic polymorphism of catechol‐O‐methyltransferase (COMT; rs4680), an enzyme regulating tonic brain dopamine levels, were assessed. Interaction of COMT by frailty and by race predicting gait speed were tested, and, if significant, analyses were stratified. Multivariable regression models of COMT predicting gait speed were adjusted for demographics and locomotor risk factors. Sensitivity analyses were repeated, stratified by clinical cutoffs of gait speed (0.6 and 1.0 m/s) instead of frailty status.

RESULTS

The interaction of COMT by frailty and COMT by race were P = .02 and P = .01, respectively. Compared with Met/Met (higher dopaminergic signaling), the Val/Val group (lower dopaminergic signaling) walked marginally more slowly in the full cohort (0.87 vs 0.89 m/s; P = .2). Gait speed differences were significant for frail (n = 220; 0.55 vs 0.63 m/s; P = .03), but not for prefrail (n = 1,691; 0.81 vs 0.81 m/s; P = .9) or nonfrail (n = 1,833; 0.98 vs 0.97 m/s; P = .7); results were similar in fully adjusted models. Among frail, associations were similar for Whites and Blacks, with statistical significance for Whites only. Associations stratified by clinical cutoffs of gait speed were not significant.

CONCLUSION

The association of dopamine‐related genotype with gait speed is stronger among adults with frailty compared with those without frailty. The potential effects of dopaminergic signaling on preserving physical function in biracial cohorts of frail adults should be further examined.
Kidney Function Modifies the Effect of Intraoperative Opioid Dosage on Postoperative Delirium
Authors: Davani Arman B. , Snyder Scott H. , Oh Esther S. , Mears Simon C. , Crews Deidra C. , Wang Nae‐Yuh , Sieber Frederick E.
Published: October 2020

BACKGROUND

There are few studies demonstrating how kidney function affects the risk of developing delirium in older adult surgical patients administered opioids. This study determined whether baseline kidney function influences the relationship between morphine equivalent dose and the development of delirium on postoperative day (POD) 2 in patients with hip fracture.

METHODS

This retrospective study analyzed emergency department (ED) estimated glomerular filtration rate (eGFR), perioperative serum creatinine, intravenous morphine equivalents, and POD2 delirium assessment by the Confusion Assessment Method in 652 patients aged 65 years or older without preoperative delirium. ED eGFR was used to divide subjects into groups by presence or absence of chronic kidney disease (CKD), and associations of opioid dose with POD2 delirium were compared using multivariable logistic regression.

RESULTS

POD2 delirium incidence was 29.8% (N = 194). Intraoperative and postanesthesia care unit (PACU) morphine equivalent dosage as well as ED eGFR were similar comparing patients with and without POD2 delirium. Age, American Society of Anesthesiologists status, and dementia were associated with delirium on POD2. The odds of POD2 delirium increased significantly with increase of intraoperative opioid in patients with CKD (odds ratio = 1.6; 95% confidence interval = 1.2–2.2), but not in patients without CKD (P‐interaction = .04). PACU or POD1 opioid doses were not associated with POD2 delirium after covariate adjustment.

CONCLUSION

This study suggests that incremental increases in intraoperative opioids combined with CKD increase odds of POD2 delirium after hip fracture repair, compared with patients without CKD.
Arginine supplementation in plant‐rich diets affects growth, feed utilization, body composition, blood biochemical indices and gene expressions of the target of rapamycin signaling pathway in juvenile Asian red‐tailed catfish (Hemibagrus wyckoiides)
Authors: Gu Dahai , Zhao Jingying , Limbu Samwel Mchele , Liang Yunan , Deng Junming , Bi Baoliang , Kong Lingfu , Yan Hui , Wang Xiaowen , Hu Qing , Gao Yu , Jia Dan , Rong Hua
Published: October 2020

Arginine (Arg) is an important essential amino acid required for optimum fish growth. However, its role in plant‐rich diets on growth and the required level in juvenile Hemibagrus wyckioides are currently unknown. This study evaluated the effects of Arg supplementation in plant‐rich diets on growth, feed utilization, whole body composition, blood biochemical indicators and gene expressions of the target of rapamycin (TOR) signaling pathway in juvenile H. wyckioides. A total of 450 fish (6.40 ± 0.06 g) were randomized into six equal groups and fed on diets with graded Arg levels: 0 (control), 3, 6, 9, 12 and 15 g/kg of dry feed for eight weeks. The results revealed that specific growth rate (SGR) and feed conversion ratio of juvenile H. wyckioides were significantly improved and reduced, respectively in fish fed on 9 g/kg of Arg supplementation (p < .05). The optimum amount of dietary Arg content in plant‐rich diets for H. wyckioides was 63.77 g/kg diet based on SGR. Feeding fish with dietary Arg supplementation ranging from 9 to 12 g/kg improved significantly (p < .05) whole body protein contents and decreased lipid deposition. The mRNA levels of TOR, eukaryotic translation initiation factor 4E (4EBP) and ribosomal protein S6 kinase 1 (S6K1) in muscle and liver were significantly affected by increasing dietary Arg levels. Meanwhile, the mRNA relative expression levels of TOR and S6K1 in the liver and muscle increased significantly as Arg supplementation increased. On the other hand, the mRNA relative expression levels of 4EBP was significantly higher in fish fed on the 9 g/kg Arg diet compared to those fed on the control and 15 g/kg Arg diets. In conclusion, our current results indicate that dietary Arg supplementation in plant‐rich diets, might activate the TOR signaling pathway, which promotes protein synthesis and reduces lipid accumulation of H. wyckioides, resulting in improved growth.
Reflections about Newman and Wittgenstein on Knowledge, Certainty and Language
Authors: McHugh Paul
Published: October 2020

In breaking out from the analytic paradigm of certainty, St John Henry Newman is credited with keeping channels open for new streams of thought to irrigate philosophy in the century after his. Contemporary commentators sometimes see themes in Newman that anticipate ones taken up by Wittgenstein after him. This paper explores some simple convergences and divergences between Newman's and Wittgenstein's tendency of thought. It draws mainly on Newman's philosophical writings, in such as the Oxford University Sermons and the Grammar of Assent, and from Wittgenstein's mid to later writings, from such works as The Blue Book, Philosophical Investigations and, of course, On Certainty. It argues that Newman's attention to speech as distinct from the rest of what might be called language is critical. This paper eventually challenges the assumption that Wittgenstein has provided the last word on approaches to knowledge such as Locke's. Instead, it proposes that within Newman there is already a more powerful critique, one that would cast Wittgenstein as the last protesting exemplar of an approach he is thought to have dismantled.
Multiple rapid swallows and rapid drink challenge in patients with esophagogastric junction outflow obstruction on high‐resolution manometry
Authors: Krause Amanda J. , Su Hui , Triggs Joseph R. , Beveridge Claire , Baumann Alexandra J. , Donnan Erica , Pandolfino John E. , Carlson Dustin A.
Published: October 2020

Background

Esophagogastric junction outflow obstruction (EGJOO) as defined by Chicago Classification of esophageal motility disorders (CCv3.0) encompasses a broad range of diagnoses, thus posing clinical challenges. Our aims were to evaluate multiple rapid swallow (MRS) and rapid drink challenge (RDC) during high‐resolution manometry (HRM) to aid identifying clinically relevant EGJOO.

Methods

Patients with a HRM diagnosis of EGJOO based on CCv3.0 that also completed MRS and RDC during HRM and barium esophagram were retrospectively identified. Radiographic EGJOO (RAD‐EGJOO) was defined by either liquid barium retention or delayed passage of a barium tablet on barium esophagram. Thirty healthy asymptomatic controls that completed HRM were also included. MRS involved drinking 2 mL for 5 successive swallows. RDC involved rapid drinking of 200 mL liquid. Integrated relaxation pressure (IRP) and presence of panesophageal pressurization (PEP) during MRS and RDC were assessed.

Key Results

One hundred one patients, mean (SD) age 56 (16) years, were included; 32% had RAD‐EGJOO, 68% did not. RAD‐EGJOO patients more frequently had elevated (>12 mmHg) upright IRP (100%), MRS‐IRP (56%), RDC‐IRP (53%), and PEP during RDC (66%) than both controls [17%; 0%; 7%; 3%] and patients without RAD‐EGJOO [83%; 35%; 39%; 41%] Having IRP >12 mmHg during both MRS and RDC was twice as likely to be associated with RAD‐EGJOO (19%) than those without RAD‐EGJOO (9%) among patients with upright IRP >12 mmHg.

Conclusions and Inferences

Adjunctive HRM maneuvers MRS and RDC appear to help identify clinically significant EGJOO. While future outcome studies are needed, comprehensive multimodal evaluation helps clarify relevance of EGJOO on HRM.
Statistical modeling of monthly rainfall variability in Soummam watershed of Algeria, between 1967 and 2018
Authors: Aieb Amir , Lefsih Khalef , Scarpa Marco , Bonaccorso Brunella , Cicero Nicola , Mimeche Omar , Madani Khodir
Published: October 2020

The monthly precipitations obtained during 51 years of measurement in 24 stations of Soummam watershed in Algeria were analyzed to describe rainfall trends and aridity state of the area using statistical modeling. The choice of distribution laws was justified by comparing fitting results of different distributions laws used in literature reviews. Hence, the p values proved that Generalized Extreme Value, Weibull (3) and Logistic the distribution law are more adequate to analyze rainfall frequencies in different part of the watershed. The diagnostic given by Q‐Q plot, P‐P plot and survival regression curve showed the period of wetness and dryness in the northeastern and the southwestern part of the watershed, respectively. Moreover, the study given by the De Martonne index explains the consequences of climate change by a new form of aridity in the watershed between 1994 and 2018.

Recommendations for Resource Managers

The annual rainfall of Soummam watershed has a moderate and irregular rainfall distribution between 1967 and 2018.

Using distribution function on monthly rainfall in each bioclimatic floor to analyze the trend of rainfall frequency gives a spatio‐temporal description of climate in the area.

Fitting by Kolmogorov‐Smirnov test allows us to choose generalized extreme value, Weibull (3) and Logistic for modeling monthly rainfall variability in each part of the watershed.

The diagnostic obtained by P‐P plot, Q‐Q plot and survival regression curve proved a change of aridity in the northeastern and southwestern part of the watershed between 1994 and 2018.
Effectiveness of Multi‐Modal Blood Management in Bernese Periacetabular Osteotomy and Periacetabular Osteotomy with Proximal Femoral Osteotomy
Authors: Shang Ji‐jun , Zhang Zhen‐dong , Luo Dian‐zhong , Cheng Hui , Zhang Hong
Published: October 2020

Objective

Bernese periacetabular osteotomy (PAO), an effective treatment for patients with developmental dysplasia of the hip (DDH), is characterized by wide exposure, cancellous bone surgery, and difficult techniques. In addition, the hip joint is deep and of rich muscles and neurovascular supply, which significantly increases bleeding. For patients who had combined proximal femoral osteotomy (PFO), the blood loss may be tremendous. The blood management for PAO is still challenging. We aimed to evaluate the effectiveness of multi‐modal blood management for PAO and PAO combined with PFO.

Patients and Methods

We retrospectively evaluated patients who had PAO with or without combined procedures from June 2010 to December 2018 in our department. The multi‐modal blood management protocol included three parts: (i) pre‐operation – autologous component blood donation and iron supplement/erythropoietin; (ii) during operation – controlled hypotension anesthesia, intraoperative auto‐blood transfusion, tranexamic acid (20 mg/kg, IV / 0.5 g local), and standardized surgical procedure to shorten surgical time; and (iii) post‐operation – no drainage used, selective allo‐blood transfusion, and ice packing technique. As the lacking of the above standard blood management protocol during PAO or PAO + PFO initially, we divided all the patients into three groups: Group A (PAO) – before protocol started, 74 hips; Group B (PAO) – after protocol finalized, 178 hips; Group C (PAO + PFO) – after protocol finalized, 55 hips. The intraoperative blood loss, surgical time, allo‐transfusion rate, pre‐ and postoperative hemoglobin were compared among groups.

Results

Both the general characteristics and preoperative hemoglobin were comparable among the three groups (P < 0.001). The intraoperative blood loss was 797.1 ± 312.2, 381.7 ± 144.0 and 544.1 ± 249.1 mL, respectively. The surgical time was 109.6 ± 18.5, 80.2 ± 20.0 and 154.3 ± 44.7 min, respectively. The allo‐transfusion rate was 86.5%, 0%, and 2%, respectively. The mean decreased value of hemoglobin on the first postoperative day of group B and group C was greater than that of group A, which was associated with the higher allo‐transfusion rate of group A. However, on the third postoperative day, the mean decreased value of hemoglobin of group B was less than that of group A and group C.

Conclusion

Perioperative multi‐modal blood management for PAO or PAO + PFO can significantly decrease intraoperative blood loss, reduce allo‐transfusion rate from over 80% to 0%, and ensure the rapid recovery of postoperative hemoglobin level.
Long‐term outcome after liver transplantation in children with type 1 glycogen storage disease
Authors: Yuen Wing Yan , Quak Seng Hock , Aw Marion M. , Karthik Sivaramakrishnan Venkatesh
Published: October 2020

Patients with GSD type 1 (von Gierke disease) are initially managed medically to maintain normoglycemia. However, if they do not achieve good metabolic control, LT is then considered. We describe the long‐term outcome of 6 children with GSD type 1 who underwent LT. Retrospective chart review of the data of 6 children with GSD type 1 who underwent LT at National University Hospital, Singapore, from May 1998 to October 2018, was performed. The median (IQR) age at diagnosis of the GSD was 1 year (0.92‐5.50) and at transplant was 13.88 years (11.46‐16.38). All of the patients had elevated liver enzymes, hypercholesterolemia, hypertriglyceridemia, and hyperlactatemia prior to transplant. All of the patients are alive at the time of analysis and follow‐up. None of them required a re‐transplant. For the three patients who had hypoglycemia pretransplant, there was no recurrence post‐transplant. All of the patients had normalization of liver enzymes by 1 year post‐transplant. Long‐term outcome of patients with GSD who underwent LT has been positive with improvement in metabolic control for most patients. We report the unusual finding of two siblings with persistent hyperuricemia post‐transplant requiring allopurinol.
The impact of regular bisoprolol on the response to salbutamol in asthma: A double‐blind randomized placebo‐controlled crossover trial
Authors: Bennett Miriam R. , Chang Catherina L. , Tuffery Chris , Hopping Sandra , Hancox Robert J.
Published: October 2020

Background and objective

Non‐selective beta‐blockers impair the bronchodilator response to beta2‐agonists. Cardio‐selective beta1‐blockers are less likely to cause this effect, yet they remain relatively contraindicated in asthma. We investigated whether the response to salbutamol is impaired during cardio‐selective beta1‐blocker treatment in people with asthma.

Methods

A random‐order, double‐blind, placebo‐controlled, non‐inferiority, crossover study was conducted comparing up to 5 mg bisoprolol daily for 2 weeks with matching placebo, with an open‐label extension of up to 10 mg bisoprolol daily. After each treatment period, mannitol was inhaled to induce bronchoconstriction with a 15% fall in forced expiratory volume in 1 s (FEV1). Immediately after mannitol challenge, salbutamol (100, 100 and 200 μg) was administered via spacer at 5‐min intervals with repeated FEV1 measures. The FEV1 recovery with salbutamol was measured as an area under recovery curve (AUC). Based on earlier research, a clinically relevant non‐inferiority limit of a 30% reduction in the AUC was set.

Results

A total of 19 adults with mild asthma and positive inhaled mannitol challenge completed the study. Adjusting for the FEV1 fall induced by mannitol and treatment sequence, the mean AUC response to salbutamol after bisoprolol was 5% lower than after placebo, with a one‐sided 95% confidence interval (CI) of 26% lower. Thirteen participants completed the open‐label extension up to 10 mg bisoprolol daily with mean AUC 11% higher after bisoprolol with a 95% CI of 5% lower.

Conclusion

The bronchodilator response to rescue salbutamol after mannitol‐induced bronchoconstriction is non‐inferior during regular treatment with the cardio‐selective beta1‐blocker, bisoprolol, compared to placebo.

Clinical Trial Registration: ACTRN12618000306213 at https://www.anzctr.org.au
Quantification of evolving moisture profiles in concrete samples subjected to temperature gradient by means of rapid neutron tomography: Influence of boundary conditions, hygro‐thermal loading history and spalling mitigation additives
Authors: Tengattini A. , Dal Pont S. , Cheikh Sleiman H. , Kisuka F. , Briffaut M.
Published: October 2020

Concrete has a tendency to spall, that is, to eject layers when subjected to high temperatures. This is an erratic phenomenon, and our understanding of the underlying physical process is still limited. A driving process is moisture transfer, whose experimental investigation has so far mostly been limited to macroscopic or point‐wise observations, limiting both our understanding and the validation of the proposed models. In this paper, a non‐contact technique, neutron imaging, is used to extract a the full‐field distribution of moisture in 3D and in real time, while the concrete is heated at high temperatures. This reveals a number of processes often underestimated or ignored in the traditional experimental approaches reported in the literature. Notably, the effect on the evolving moisture profiles of varying heating rates for multiple insulation techniques as well the strong influence of the addition of spalling‐mitigating additives is presented. The first ever example of neutron tomography of a spalled sample is also reported, and some preliminary analyses of the effect that moisture clog formation and heating rates have on it are revealed.
Ultrasonographic evaluation of the width, thickness, and length of the normal linea alba in standing and dorsal recumbent horses
Authors: Verkade Maria E. , Suthers Joanna , Wiemer Peter , Martens Ann , De Clercq Eva , Burford John
Published: October 2020

Objective

To determine the variability in length, width, and thickness of the equine linea alba (LA) and the effect of a standing vs dorsal recumbent position on these measurements.

Study design

Descriptive anatomical comparative study.

Animals

Standing horses (N = 75; in 30 horses, measurements were obtained in dorsal recumbency first and repeated after horses were standing).

Methods

Linea alba length was measured in standing position from xiphoid to umbilicus, and transverse ultrasonographic images were obtained at five reference points to measure LA width and thickness. In 30 horses, measurements were obtained in dorsal recumbency first and repeated after horses were standing.

Results

There was wide variation in LA width and thickness between standing horses, with gradual increase from xiphoid (range, 0.14‐0.64 cm) to umbilicus (range, 0.2‐2.97 cm). Linea alba length in standing position was 51.09 ± 6.219 cm. Width was independent of the size of the horse; thickness and length were correlated at some reference points to height (r = 0.346‐585, P < .05) and weight (r = 0.324‐0.642, P < .05). Different LA shapes could be identified. In dorsal recumbency, the LA was smaller in width at all reference points (15%–23%, P < .05) and shorter (20%, P < .001) compared with standing.

Conclusion

In addition to the wide variability in LA measurements and shapes between horses, there was a significant decrease in LA width and length when horses changed from standing to dorsal recumbency.

Clinical significance

The difference in LA length and width between dorsal recumbency and when standing could increase tension on sutures after laparotomy and should be taken into account when surgeons are closing the abdomen.
Pore-Scale Study of the Thermochemical Process in Porous Media With Immiscible Phase by Lattice Boltzmann Method
Authors: Xu Zhiguo , Zhou Xiao
Published: October 2020

Reactive flow happens in carbonate rocks which are porous media during acidification. In this study, a thermochemical dissolution model based on the lattice Boltzmann method (LBM) is established to investigate the complex thermochemical process in porous media with immiscible phase at pore scale. In the model, the immiscible fluid flow, solute transport, and heat transfer are solved by Shan–Chen multicomponent LB model, mass transport LB model, and multicomponent thermal LB model, respectively. The porous media is generated by the quartet structure generation set, and the evolution of solid phase is addressed by volume of pixel (VOP) method. The detailed thermochemical process in porous media with immiscible phase is revealed, and the effects of velocity, concentration, and temperature on mass and heat transfer are further analyzed. The results show that increasing inlet velocity, inlet concentration, and temperature accelerates acidizing process and influences the temperature evolution in porous media significantly.
Reconfigurable Acoustic Arrays With Deployable Structure Based on a Hoberman–Miura System Synthesis
Authors: Zhao Ningxiner , Harne Ryan L.
Published: October 2020

Curved surfaces are often used to radiate and focus acoustic waves. Yet, when tessellated into reconfigurable surfaces for sake of deployability needs, origami-inspired acoustic arrays may be challenging to hold into curved shape and may not retain flat foldability. On the other hand, deployable mechanisms such as the Hoberman ring are as low-dimensional as many origami tessellations and may maintain curved shape with ease due to ideal rigid bar compositions. This research explores an interface between a Hoberman ring and Miura-ori tessellation that maintain kinematic and geometric compatibility for sake of maintaining curved shapes for sound focusing. The Miura-ori facets are considered to vibrate like baffled pistons and generate acoustic waves that radiate from the ring structure. An analytical model is built to reveal the near field acoustic behavior of acoustic arrays resulting from a Hoberman–Miura system synthesis. Acoustic wave focusing capability is scrutinized and validated through proof-of-principle experiments. Studies reveal wave focusing phenomena distinct to this manifestation of the acoustic array and uncover design and operational influences on wave focusing effectiveness. The results encourage exploration of new interfaces between reconfigurable mechanisms and origami devices where low-dimensional shape change is desired.
Uncertainty Quantification With Sparsely Characterized Parameters: An Example Applied to Femoral Stem Mechanics
Authors: Wanki Godlove , Ekwaro-Osire Stephen , Dias João Paulo , Cunha Americo
Published: October 2020

The advent of state-of-the-art additive manufacturing (AM) processes has facilitated the manufacturing of complex orthopedic metallic implants such as femoral stems with porous portions based on lattice structures. These struts often have rough and not smooth textured surfaces, for which the irregularities may influence mechanical properties. To make robust predictions about the behavior of this kind of system, the variability effect of its parameters on the stem stiffness must be considered in the processes of modeling and design of porous femoral stems. Also, to improve the credibility of computational models used for hip implant analysis, which involves numerous uncertainties, there is a need for rigorous uncertainty quantification (UQ) framework for proper model assessment following a credible-modeling standard. This work proposes a UQ framework in the presence of sparsely characterized input parameters using the maximum entropy principle for analyzing a femoral stem implant model and thus to clarify how uncertainties impact the key properties of a porous femoral stem. In this study, uncertainties in the strut thickness, pore size, Young's modulus, and external forcing are considered. The UQ framework is validated using experimental results available from literature, following the guidelines set in an ASME standard.
Code Verification of a Pressure-Based Solver for Subsonic Compressible Flows
Authors: Muralha João , Eça Luís , Klaij Christiaan M.
Published: October 2020

Although most flows in maritime applications can be modeled as incompressible, for certain phenomena like sloshing, slamming, and cavitation, this approximation falls short. For these events, it is necessary to consider compressibility effects. This paper presents the first step toward a solver for multiphase compressible flows: a single-phase compressible flow solver for perfect gases. The main purpose of this work is code verification of the solver using the method of manufactured solutions. For the sake of completeness, the governing equations are described in detail including the changes to the SIMPLE algorithm used in the incompressible flow solver to ensure mass conservation and pressure–velocity–density coupling. A manufactured solution for laminar subsonic flow was therefore designed. With properly defined boundary conditions, the observed order of grid convergence matches the formal order, so it can be concluded that the flow solver is free of coding mistakes, to the extent tested by the method of manufactured solutions. The performance of the pressure-based SIMPLE solver is quantified by reporting iteration counts for all grids. Furthermore, the use of pressure–weighted interpolation (PWI), also known as Rhie–Chow interpolation, to avoid spurious pressure oscillations in incompressible flow, though not strictly necessary for compressible flow, does show some benefits in the low Mach number range.
Comparison of Neutron-Gamma Separation Qualities of Various Organic Scintillation Materials and Liquid Scintillator LSB-200
Authors: Matěj Zdeněk , Mravec Filip , Jančár Aleš , Košťál Michal , Kučera František , Cvachovec František , Prenosil Václav , Kopecký Zdeněk , Čulen Jiří , Pecák Oldřich
Published: October 2020

In this work, we compare the pulse-shape discrimination (PSD) properties of newly developed liquid scintillator LSB-200, EJ-299-33A, BC-501A, stilbene, p-terphenyl, and Hidex Aqualight in neutron field generated by the LVR-15 reactor with silicon filter utilization. Pulses from the scintillators are processed by the Neutron-Gamma spectrometer. This spectrometric system with fast digitizer card contains two analog–digital converters with a resolution of 12 bits and sampling frequency 500 × 106 Hz. For photomultiplier linearity improvement, the active divider has been used. Measured data from scintillators have been processed using the integration method and compared. The results are presented.
Analysis of a FAME/MLL Screw Multi-Stage Compressor for High Temperature, High Pressure Vapor Compression Refrigeration Cycle
Authors: Anderson Kevin R. , Steele Trevor
Published: October 2020

This paper presents the analysis and design of a compressor for application to a Fatty Acid Methyl Ester (FAME) Methyl Linoleate (MLL) bio-refrigerant cascade working cycle. This working fluid is being used in the topping cycle of an active electronics payload cooling system design to operate at elevated temperatures and pressures such as those witnessed by a Venus lander. The twin-screw, three-stage compressor operates at escalated temperatures of approximately 520 °C (960 °F). The total compressor power of 143.4 W is shared as 43.5 W, 47.7 W, and 53.3 W over stages 1, 2, and 3, respectively. The screw compressor is baselined with a D = 1 inch diameter rotor and an L/D (stroke/bore) ratio of L/D = 2 per stage. The compression ratio corresponds to a volume ratio of 6.5. The swept volume for a 4+6 rotor configuration is estimated to be 1.13 CFM at 2000 RPM with an asymmetric profile and no leakage. The volumetric efficiency of the compressor is estimated to be on the order of 80% due to the higher molecular weight of the FAME/MLL working fluid. The SCORG turbomachinery software is used to verify the thermodynamics analysis and affords a volumetric displacement of 0.025 L/rev at 2000 RPM and 80% adiabatic efficiency.
Numerical Simulation of Twin-Parachute Inflation Process for Aircraft Ejection Escape
Authors: Wang Liwu , Tang Mingzhang , Zhang Sijun
Published: October 2020

In order to study the safe distance between twin-parachute during their inflation process for fighter ejection escape, the fighter was equipped with two canopies and two seats, two types of parachute were used to numerically simulate their inflation process, respectively. One of them is C-9, the other a slot-parachute (S-P). Their physical models were built, then the meshes inside and around both parachutes were generated for fluid-structure interaction (FSI) simulation. The penalty function and the arbitrary Lagrangian-Eulerian (ALE) method were employed in the FSI simulation. To validate the numerical model for FSI simulation, at first the single parachute of the twin-parachute was used for the FSI simulation, the predicted inflation times for both types of parachute were compared with the experimental data. The computed results are in good agreement with experimental data. As a result, the inflation times were predicted with twin-parachute for both kinds of parachute. On the basis of the locations of ejected seats after the separation of seat and pilot, the initial locations and orientations of twin-parachute were also obtained. The numerical simulations for both kinds of parachute were performed by the FSI method, respectively. Our results illustrate that when the interval time for two seats ejected is greater than 0.25s, two pilots attached the twin-parachute are safe, and the twin-parachute would not interfere each other. Moreover, our results also indicate that the FSI simulation for twin-parachute inflation process is feasible for engineering applications and have a great potential for wide use.
Machine Learning for Turbulence Modeling and Predictions
Authors: Bhushan S. , Burgreen Greg W. , Martinez D. , Brewer Wes
Published: October 2020

A stand-alone machine learned turbulence model is applied for the solution of integral boundary layer equations, and issues and constraints associated with the model are discussed. The results demonstrate that grouping flow variables into a problem relevant parameter for input during machine learning is desirable to improve accuracy of the model. Further, the accuracy of the model can be improved significantly by incorporation of physics-based constraints during training. Data driven machine learning training requires trial-and-error approach, shows oscillations in a posteriori predictions, and shows unphysical results when used with arbitrary initial condition, as the query is essentially extrapolations. Physics informed machine learning addresses the above limitations, and is identified to be a viable approach for development of machine learned turbulence model.
Blood Flow Simulations of Particle Trapping in Models of Arterial Bifurcations
Authors: Xu Qihang , Agarwal Ramesh K.
Published: October 2020

This paper describes the particle trapping mechanism in blood flow in different arterial bifurcation models. For validation of CFD calculations, a T-junction model and a Y-junction model are analyzed. In both the models, there is one inlet pipe with two outlet pipes creating a symmetric bifurcation at some angle from the centerline of the inlet pipe. Naiver-Stokes (RANS) equations are solved for single phase laminar flow using the commercial CFD software ANSYS Fluent. After validation, Eulerian simulations are performed by using the Discrete Phase Model (DPM) for two-phase flow with particles injected in different bifurcation models with bifurcation angle of an outlet pipe varying from 80° to 100° w.r.t the centerline of the inlet pipe (90° being the bifurcation angle of T-junction). By changing the average Reynolds number of the flow and the injected particle diameters, the mechanism of particle trapping is investigated in laminar flow. The contours of velocity magnitude, pressure and wall shear stress are also obtained and analyzed. It is found that the particle trapping increases as the bifurcation angle decreases from 90° and becomes negligible as the bifurcation angle increases from 90°. This is a very important result which has never been reported in the previous literature. In addition, turbulent flow computations for T-junction flow are performed using the SST k-ω and Wray-Agarwal turbulence models. Finally, the influence of stenosis in Y-junction is studied and analyzed. The results have implications in understanding the hemodynamic flows in arterial bifurcations without and with stenosis.
Using Liquid Spray Formations to Improve Aerodynamic Performance of Airfoils
Authors: Loubimov George , Fontes Douglas , Loving Garett , Kinzel Michael
Published: October 2020

Previous research on firefighting aircraft which employ dumping water from their lower surface to extinguish flames has shown that there are added lift benefits during dumping maneuvers which do not directly correlate to the exchange in water mass. In this case study, the effects of liquid spray formations on two dimensional aerodynamics are investigated by use of a numerical approach. Studies include chord-wise variation of liquid-jets and variation of spray momentum ratios. Comparisons are also made to previous, single-phase, jet-flap numerical experiments and show favorable agreement. Findings show that increases in lift coefficient and decreases in drag coefficient are observed with the presences of liquid jets located on the lower surface.
Part Load Instability and Rotating Stall in a Multistage Low Specific Speed Pump
Authors: Vermunt E. M. A. , Bruurs K. A. J. , van der Schoot M. S. , van Esch B. P. M.
Published: October 2020

A new diffuser design is developed for a low specific speed, multistage pump. In this design the diffuser and the de-swirl vanes are integrated into single vanes. This creates diffuser channels that extend from behind the impeller exit through the cross-over, up to the eye of the next stage impeller. Experiments show the occurrence of a saddle type instability in the head curve. At a critical flow rate of close to 50% of the flow rate at Best Efficiency Point (BEP), the head drops by 7% of the head at BEP. In this study Computational Fluid Dynamics (CFD) are used in an effort to understand the underlying flow phenomena.

The head curve that is obtained with the transient CFD simulations contains a saddle type instability at a flow rate that is approximately the same as in the experiments, but with a lower magnitude. At flow rates higher than the critical flow rate, the predicted head and power are in very good agreement with the experimental data. At flow rates lower than the critical flow rate, the head and power are slightly over-predicted. An analysis of the pressure distribution in the pump reveals that the head loss at different flow rates in the diffuser shows a discontinuity at the critical flow rate. Since both the impeller head and the head loss in the vaneless gap increase continuously for decreasing flow rate, this is an indication that the cause of the head instability lies in the diffuser. Moreover, a strong increase in the variability of head and power at flow rates below the critical flow suggests that the phenomenon is unsteady.

Flow patterns in the impeller and in the diffuser, as calculated by CFD, show a high degree of periodicity and are very similar for flow rates down to the critical flow rate. However, for lower flow rates the flow pattern changes completely. A single rotating stall cell is observed that causes two or three neighboring diffuser channels to stall, leading to a significantly lower flow rate or even a reversed flow. This stall pattern rotates in the direction of impeller rotation at a very low frequency of approximately 3.3% of the impeller rotation frequency.
Evaluation of Reattaching Shear-Layer in Compressible Turbulent Flows: A Large Eddy Simulation Approach
Authors: Zangeneh Rozie
Published: October 2020

The boundary-layer separation and subsequent reattachment due to the free shear-layer and Shockwave interaction have a significant impact on the aerothermal design of supersonic aerospace systems. This problem is prevalent in high-speed flights and can significantly affect the skin friction, aerodynamic loads, and heat transfer. In recent years, considerable progress has been achieved in the prediction of turbulent compressible flows using high-fidelity models. However, the prediction of reattaching free shear-layer and shockwave interactions still needs to be modified for accurate predictivity. The objective of this study is to investigate the ability of a new computational fluid dynamics model to predict these critical flow phenomena accurately. The new high-fidelity model is based on a collocated central scheme, which has the advantage of being a Riemann free solver, and therefore easy to implement on unstructured grids. It is developed to capture any discontinuities at shocks while it is able to capture broadband spatial and temporal variations in turbulent flows with minimal dissipation and dispersion. Large Eddy Simulation is performed on a compression corner at a Mach number of 2.92 and a high Reynolds number. The geometry of the model is specifically designed to isolate the reattachment process of a high-speed separated flow. To examine the accuracy of the predicted results, results of velocity profiles in the free shear-layer, boundary layer development, turbulent fluctuations, and pressure are compared to an experimental effort by Princeton. Excellent agreement is observed, and it is recommended that the model can be used to investigate the physics of the shock unsteadiness due to interaction with a free shear-layer.