bluuebunny/crossref_metadata_2025 huggingface dataset:
The ancestral Andalusian water courts: a resilient model for contemporary Islamic banking and finance
Authors: Martín-Cervantes Pedro Antonio , Cruz Rambaud Salvador , Valls Martínez María del Carmen
Published: March 2021

Purpose

This paper aims to examine the functioning and organizational structure of the historic Andalusian water courts, institutions of Islamic origin whose basic model should be considered in light of the regulation of modern Islamic banking and finance.

Design/methodology/approach

The methodology of this study has been focused on the contextualization of al-Andalus during the European Middle Ages, highlighting its enormous contributions and implications in the creation of Western knowledge. In the same way, the ordinances of the Castilian-Aragonese kings, aimed at the persistence of the Andalusian water courts in the Southeast of Spain after the Muslim period, have been used as the main sources of reference.

Findings

This research has detected that the main features of the Andalusian water courts, i.e. integrity, democracy, transparency, credibility, moral authority or simplicity (among many others), can be conveniently replicated in the scope of the current Islamic banking and finance.

Research limitations/implications

Several implications can be derived from this study: first, it highlights the total resilience of a regulatory model that “it was already there,” given by the history of the Andalusian civilization. This model will be always welcomed by the Muslim community in Western countries as it is a matter of regulating themselves according to the way their ancestors did. The main limitation faced by this research is the relative scarcity of original sources, which is justifiable given that most of the royal ordinances come from the 13th century, having unfortunately lost a good number of sources over time.

Originality/value

This paper seeks a feasible alternative to the controversy arising from the resolution of possible disputes in Islamic banking and finance taking into account that Western judges do not know (nor do they have to) the principles on which this discipline is based. The application of the historical Andalusian model would allow the creation of an independent jurisdiction, while subordinated to the established juridic power, without contravening the principle of “jurisdictional unity.” The last element that gives an added value to this research is spreading the achievements of the Andalusian culture and civilization, unjustly omitted by a great part of the existing literature.
Promoting sustainable ventures among university students in Pakistan: an empirical study based on the theory of planned behavior
Authors: Waris Idrees , Farooq Muhammad , Hameed Irfan , Shahab Atif
Published: March 2021

Purpose

This study aims to examine the drivers of sustainable entrepreneurship intention (SEI) among university students in Pakistan.

Design/methodology/approach

A survey-based methodology was used to collect the data from the participants. Further, this study used covariance-based structural equation modeling to test the proposed hypotheses.

Findings

The findings of this study confirm that the model of sustainable entrepreneurship is effective as it explains 83% variance to predict SEI among the students.

Originality/value

This research has contributed to the literature of sustainable entrepreneurship and proposed valuable insights in understanding the influence of sustainability education, sustainability attitude, self-efficacy and self-identity on SEI.
Producing wood at least cost to biodiversity: integrating Triad and sharing–sparing approaches to inform forest landscape management
Authors: Betts Matthew G. , Phalan Benjamin T. , Wolf Christopher , Baker Susan C. , Messier Christian , Puettmann Klaus J. , Green Rhys , Harris Scott H. , Edwards David P. , Lindenmayer David B. , Balmford Andrew
Published: March 2021

Forest loss and degradation are the greatest threats to biodiversity worldwide. Rising global wood demand threatens further damage to remaining native forests. Contrasting solutions across a continuum of options have been proposed, yet which of these offers most promise remains unresolved. Expansion of high‐yielding tree plantations could free up forest land for conservation provided this is implemented in tandem with stronger policies for conserving native forests. Because plantations and other intensively managed forests often support far less biodiversity than native forests, a second approach argues for widespread adoption of extensive management, or ‘ecological forestry’, which better simulates natural forest structure and disturbance regimes – albeit with compromised wood yields and hence a need to harvest over a larger area. A third, hybrid suggestion involves ‘Triad’ zoning where the landscape is divided into three sorts of management (reserve, ecological/extensive management, and intensive plantation). Progress towards resolving which of these approaches holds the most promise has been hampered by the absence of a conceptual framework and of sufficient empirical data formally to identify the most appropriate landscape‐scale proportions of reserves, extensive, and intensive management to minimize biodiversity impacts while meeting a given level of demand for wood. In this review, we argue that this central challenge for sustainable forestry is analogous to that facing food‐production systems, and that the land sharing–sparing framework devised to establish which approach to farming could meet food demand at least cost to wild species can be readily adapted to assess contrasting forest management regimes. We develop this argument in four ways: (i) we set out the relevance of the sharing–sparing framework for forestry and explore the degree to which concepts from agriculture can translate to a forest management context; (ii) we make design recommendations for empirical research on sustainable forestry to enable application of the sharing–sparing framework; (iii) we present overarching hypotheses which such studies could test; and (iv) we discuss potential pitfalls and opportunities in conceptualizing landscape management through a sharing–sparing lens. The framework we propose will enable forest managers worldwide to assess trade‐offs directly between conservation and wood production and to determine the mix of management approaches that best balances these (and other) competing objectives. The results will inform ecologically sustainable forest policy and management, reduce risks of local and global extinctions from forestry, and potentially improve a valuable sector's social license to operate.
Feeling Heard: Inclusive Education, Transformative Learning, and Productive Struggle
Authors: Murdoch Diana , English Andrea R. , Hintz Allison , Tyson Kersti
Published: March 2021

Abstract

Developments in international inclusive education policy, including in prominent UN documents, often refer to the aim of a quality education for all. Yet, it remains unclear: What exactly is meant by quality education? And, under what conditions are quality educational experiences possible for all learners? In this essay, Diana Murdoch, Andrea English, Allison Hintz, and Kersti Tyson bring together research on inclusive education with philosophy of transformative learning, in particular John Dewey and phenomenology, to further the discussion on these two questions. The authors argue that teacher–learner relationships, of a particular kind, are necessary for fostering environments wherein all learners have access to quality educational experiences associated with productive struggle as an indispensable aspect of transformative learning processes. They define such relationships as “educational relationships that support students to feel heard.” In developing their argument, the authors first analyze the concept of productive struggle, an aspect of learning increasingly recognized in research and policy as an indicator of quality education. Second, they discuss three necessary, though not sufficient, conditions for the teacher to cultivate educational relationships that support students to feel heard. Third, they draw out connections between environments that support feeling heard and those that support productive struggle, and they discuss teachers' challenges and risk‐taking in creating such environments. The authors close with a discussion of implications for international policy, practice, and research.
Prestimulus alpha power but not phase influences visual discrimination of long‐duration visual stimuli
Authors: Michail Georgios , Toran Jenner Lino , Keil Julian
Published: March 2021

Occipital oscillations in the alpha band are closely related to visual perception and attention. In multiple studies, increased alpha power has been shown to reduce detection rates of hard‐to‐detect visual stimuli. Recent studies explain this finding by a shift in perceptual bias. Moreover, the phase of alpha oscillations prior to stimulus onset appears to be critical for the detection of visual stimuli. This is explained by a shift in cortical excitability over the course of each alpha cycle. However, prior studies often used short presentation times of visual stimuli at the perceptual threshold. Here, we use longer presentation times to elucidate whether the same mechanisms hold for the perception of salient but challenging visual stimuli presented for up to 1,500 ms. To this end, we presented participants with hard to distinguish but salient upright or tilted Gaussian gratings in a two‐alternative forced choice task, while recording occipital electroencephalographic activity. Previous reports link alpha power to stimulus detection hit rates, and we found that low prestimulus power at the individual alpha frequency relates to higher perceptual accuracy. Contrary to recent findings, we neither found an influence of alpha power on criterion, nor an influence of alpha phase on perception or response speed. We argue that longer presentation times might attenuate a possible response bias, and increased excitability might sharpen the discrimination ability, thereby leading to increased perceptual accuracy and unaffected response criterion.
Effect of surface chemistry‐modified polycaprolactone scaffolds on osteogenic differentiation of stem cells from human exfoliated deciduous teeth
Authors: Jitpibull Jirasak , Tangjit Nathaphon , Dechkunakorn Surachai , Anuwongnukroh Niwat , Srikhirin Toemsak , Vongsetskul Thammasit , Sritanaudomchai Hathaitip
Published: March 2021

The aim of this study was to investigate the effect of surface modification of a polycaprolactone scaffold on promoting osteogenic differentiation of stem cells from human exfoliated deciduous teeth. Four different polycaprolactone scaffold were evaluated: untreated; coated with hyaluronic acid; coated with gelatin; and coated with hyaluronic acid and then with gelatin. The resulting scaffolds were characterized using scanning electron microscopy and attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR). Human stem cells were cultured on the modified scaffolds placed in osteogenic differentiation medium. During culture, the osteogenic potential of the stem cells was examined by evaluating alkaline phosphatase activity and staining intensity, expression of osteoblastic‐specific genes, and matrix mineralization. Scanning electron microscopy and ATR‐FTIR confirmed productive biomacromolecular surface treatment of the polycaprolactone scaffold. All scaffolds permitted differentiation of stem cells into osteoblastic cells, but the gelatin‐coated polycaprolactone scaffold facilitated osteogenesis of a larger number of stem cells than the untreated and the hyaluronic acid‐coated scaffolds. We demonstrate that gelatin is an appropriate macromolecule for modifying the surface of an electrospun polycaprolactone fibre scaffold that is used subsequently in bone tissue engineering applications.
FIRM DYNAMICS WITH FRICTIONAL PRODUCT AND LABOR MARKETS
Authors: Kaas Leo , Kimasa Bihemo
Published: March 2021

We analyze the joint dynamics of prices, productivity, and employment across firms, building a dynamic equilibrium model of heterogeneous firms who compete for workers and customers in frictional labor and product markets. Using panel data on prices and output for German manufacturing firms, the model is calibrated to evaluate the quantitative contributions of productivity and demand for the labor market. Product market frictions decisively dampen the firms' employment adjustments to productivity shocks. We further analyze the impact of aggregate shocks to the first and second moments of productivity and demand and relate them to business‐cycle features in our data.
Intraprostatic prophylactic antibiotic injection in patients undergoing transrectal ultrasonography‐guided prostate biopsy
Authors: Shobeirian Farzaneh , Zerafatjou Nikan , Ghomi Zahra , Vafaei Mohamad , Darabi Mohsen
Published: March 2021

Objectives

To evaluate the efficacy of intraprostatic injection of prophylactic antibiotics for the prevention of infections following transrectal ultrasonography‐guided prostate biopsy.

Methods

In this prospective interventional study, patients aged between 40 and 70 years with clinical indications for transrectal ultrasonography‐guided prostate biopsy were enrolled. Consecutive patients who received intraprostatic injection of amikacin coupled with oral ciprofloxacin were compared with historical controls receiving only prophylactic oral fluoroquinolones prior to biopsy. Patients were followed for 7 days after biopsy for signs and symptoms of infection.

Results

A total of 210 patients were included in this study (mean age 65.7 ± 7.8 years). Among patients without intraprostatic injection, nine (8.6%) developed infectious complications (lower urinary tract infection in seven patients, and prostatitis in two), which led to hospitalization in six patients (5.7%). None of the patients who received intraprostatic antibiotic injection developed infectious complications. The difference in the incidence of post‐transrectal ultrasonography‐guided biopsy infections between the two groups was statistically significant (P = 0.003).

Conclusion

Local intraprostatic antibiotic injection during transrectal ultrasonography‐guided prostate biopsy adjuvant to oral fluoroquinolones can significantly reduce the rate of post‐biopsy infectious complications.
Saudi Arabia's sustainable tourism development model: New empirical insights
Authors: Iswan  , Khan Aqeel , Kadir Firdaus Khairi Abdul , Jabor Mohd Khata , Anis Siti Nisrin Mohd , Zaman Khalid
Published: March 2021

The study extended the conventional Autoregressive Distributed Lag (ARDL) model into the lead model, supported with a partial adjustment model and adaptive expectation model. The ARDL‐LEAD modelling is applied to Saudi Arabia's tourism industry to assess the country's environmental sustainability agenda (ESA) by using monthly time series data from 1995M01‐2018M12. The short‐run results confirmed the Environmental Kuznets Curve (EKC) hypothesis with the lag variables, while the U‐shaped relationship was found between economic growth (EG) and CO2 emissions with the leads variable. The inbound tourism and trade openness (TOP) decrease CO2 emissions at the lead factor in the short‐run. The long‐run relationship verified the U‐shaped relationship between EG and CO2 emissions, while TOP openness increases CO2 emissions to substantiate 'pollution haven hypothesis (PHH)' in a country. The Wald Granger causality shows the different variations at the current period and forecasted estimates. The Granger estimates at the current level confirmed the growth‐led emissions (GLE), tourism‐led emissions (TLE), and tourism‐led growth (TLG) hypotheses, while at forecast estimates, the results substantiate the TLE and emissions‐led growth (ELD) hypotheses in a country.
Factors affecting psychosocial development of very low birth weight infants at 18 and 36 months of age
Authors: Inoue Miyuki , Nemoto Atsushi , Naito Atsushi , Shiozawa Yukimi , Kobayashi Ayaka
Published: March 2021

Aim

To identify relationships between neonatal factors including conditions and treatments, nurturing environment, and psychosocial development of children born at very low birth weight (VLBW).

Methods

In this longitudinal study, the medical records of 113 VLBW infants were examined, and the children were then followed up at 18 and 36 months of age. Their developmental quotient (DQ) was assessed using the Kyoto Scale of Psychological Development (KSPD), and their parents were asked about their own health, financial situation, education, and family support. Pearson's correlation and stepwise multiple regression analyses were used to explore relationships between DQ, potentially significant predictors on the KSPD, and nurturing environment.

Results

DQ at 18 months was associated with the following neonatal factors: mechanical ventilation days (β = −.241, p = .020), Apgar score at 5 min (β = .278, p = .005), periventricular leukomalacia (β = −.218, p = .006), and treatment for retinopathy of prematurity (β = −.171, p = .048) (adjusted R2 = .32). DQ at 36 months was associated with the following neonatal and parenting factors: mechanical ventilation days (β = −.354, p < .001), periventricular leukomalacia (β = −.207, p = .009), sex (β = −.199, p = .011), mother's educational background (β = −.304, p < .001), mother's health status (β = −.159, p = .042) (adjusted R2 = .35).

Conclusions

These findings suggest that in addition to neonatal clinical parameters including conditions and treatments, the nurturing environment after discharge from the neonatal intensive care unit influences the psychosocial development of VLBW infants.
Developmental regulation of barrier‐ and non‐barrier blood vessels in the CNS
Authors: Ben‐Zvi A. , Liebner S.
Published: March 2021

The blood–brain barrier (BBB) is essential for creating and maintaining tissue homeostasis in the central nervous system (CNS), which is key for proper neuronal function. In most vertebrates, the BBB is localized to microvascular endothelial cells that acquire barrier properties during angiogenesis of the neuroectoderm. Complex and continuous tight junctions, and the lack of fenestrae combined with low pinocytotic activity render the BBB endothelium a tight barrier for water‐soluble molecules that may only enter the CNS via specific transporters. The differentiation of these unique endothelial properties during embryonic development is initiated by endothelial‐specific flavours of the Wnt/β‐catenin pathway in a precise spatiotemporal manner. In this review, we summarize the currently known cellular (neural precursor and endothelial cells) and molecular (VEGF and Wnt/β‐catenin) mechanisms mediating brain angiogenesis and barrier formation. Moreover, we introduce more recently discovered crosstalk with cellular and acellular elements within the developing CNS such as the extracellular matrix. We discuss recent insights into the downstream molecular mechanisms of Wnt/β‐catenin in particular, the recently identified target genes like Foxf2, Foxl2, Foxq1, Lef1, Ppard, Zfp551, Zic3, Sox17, Apcdd1 and Fgfbp1 that are involved in refining and maintaining barrier characteristics in the mature BBB endothelium. Additionally, we elute to recent insight into barrier heterogeneity and differential endothelial barrier properties within the CNS, focussing on the circumventricular organs as well as on the neurogenic niches in the subventricular zone and the hippocampus. Finally, open questions and future BBB research directions are highlighted in the context of taking benefit from understanding BBB development for strategies to modulate BBB function under pathological conditions.
The therapeutic effects of journal writing for parents of PICU patients: A research brief
Authors: Board Rhonda
Published: March 2021

Purpose

The admission of a critically ill child to the Pediatric Intensive Care Unit (PICU) is well known to be a stressful experience for parents. The overall aim of this study was to explore whether the use of journal writing would be acceptable and feasible to PICU parents as a stress‐reducing intervention.

Design and Methods

A longitudinal, quasi‐experimental two‐group study design was conducted with a convenience sample of 28 parents. Experimental group parents were given instructions on how to journal write each day their child was hospitalized, while control group parents received usual care. Data were collected at three evaluation time points.

Results

The response rates at the final time point (6–8 weeks after discharge) were 93% for the control group and 71% for the experimental group. Outcome measure trends were similar for parents in both groups, with most perceiving mild‐to‐moderate stress from the PICU environment. A significant correlation was found between the perceived stress from the PICU environment and parental traumatic stress symptoms 6–8 weeks postdischarge for the experimental group (Time 1 r = .919, p = .00; Time 2 r = .969, p = .00). The majority of the experimental group parents wrote in their journals daily and found the intervention helpful.

Practice Implications

Although further research is warranted, journal writing is a simple‐to‐do intervention that should be considered for use with future PICU parents.
Coagulation status, fibrinolysis, and platelet dynamics in dogs with chronic inflammatory enteropathy
Authors: Jablonski Wennogle Sara A. , Olver Christine S. , Shropshire Sarah B.
Published: March 2021

Background

Coagulation status is poorly understood in dogs with chronic inflammatory enteropathy (CIE). Fibrinolytic activity and platelet dynamics have not been evaluated in CIE dogs.

Objectives

To assess coagulation status and fibrinolysis in normoalbuminemic CIE dogs (CIE‐N) and CIE dogs with protein‐losing enteropathy (CIE‐PLE) compared to healthy controls (HC). To evaluate thromboelastography (TEG) variable differences between groups and for correlations with clinicopathologic data. To report platelet dynamics in CIE dogs.

Animals

Twenty‐five client‐owned dogs with CIE (n = 16 CIE‐N; n = 9 CIE‐PLE); 14 HC beagle dogs.

Methods

All dogs had tissue factor + tissue plasminogen activator TEG. Nine of 25 CIE dogs had whole blood impedance platelet aggregometry. The TEG variables and coagulation data were compared between all CIE vs HC dogs, CIE‐N dogs vs HC, and CIE‐PLE dogs vs HC. Clinicopathologic and coagulation data were available for CIE dogs and assessed for correlation to TEG variables.

Results

Dogs with CIE had higher maximum amplitude (MA; P < .001), longer clot lysis times (CLTs; P < .001), lower % lysis after 30 minutes (LY30; P < .001), and % lysis after 60 minutes (LY60; P < .001) compared to HC, suggesting hypercoagulability and hypofibrinolysis. When separated out, both CIE‐N and CIE‐PLE dogs had higher MA, longer CLT, and lower LY30 and LY60 compared to HC. Serum albumin and 25‐hydroxyvitamin D (25[OH]D) concentrations, and plasma antithrombin and fibrinogen concentrations moderately correlated with MA.

Conclusions and Clinical Importance

Normoalbuminemic and hypoalbuminemic CIE dogs were considered hypercoagulable based on TEG compared to HC. Some CIE dogs displayed hypofibrinolytic phenotypes on TEG.
Superficial mycoses, a matter of concern: Global and Indian scenario‐an updated analysis
Authors: Sharma Bharti , Nonzom Skarma
Published: March 2021

Superficial mycoses of skin, nails and hair are among the common fungal infections. They are caused by dermatophytes, non‐dermatophyte moulds, yeasts and yeast‐like fungi. Such fungal infections are widespread all over the world and are predominant in tropical as well as subtropical regions. Environmental factors, such as warm, humid and pitiable hygienic conditions, are conducive for their growth and proliferation. Although it does not cause mortality, it is known to be associated with excessive morbidity which may be psychological or physical. This affects the quality of life of the infected individuals which leads to a negative impact on their occupational, emotional and social status. Such infections are increasing on a global scale and, therefore, are of serious concern worldwide. This review article covers the global and Indian scenario of superficial mycoses taking into account the historical background, aetiological agents, prevalence, cultural and environmental factors, risk factors, pathogenesis and hygienic practices for the prevention of superficial mycoses.
Mesophyll‐derived sugars are positive regulators of light‐driven stomatal opening
Authors: Flütsch Sabrina , Santelia Diana
Published: March 2021

Guard cell membrane ion transport and metabolism are deeply interconnected, and their coordinated regulation is integral to stomatal opening. Whereas ion transport is exceptionally well understood, how guard cell metabolism influences stomatal movements is less well known. Organic metabolites, such as malate and sugars, fulfill several functions in guard cells during stomatal opening as allosteric activators, counter‐ions, energy source and osmolytes. However, their origin and exact fate remain debated. Recent work revealed that the guard cell carbon pool regulating stomatal function and plant growth is mostly of mesophyll origin, highlighting a tight correlation between mesophyll and guard cell metabolism. This review discusses latest research into guard cell carbon metabolism and its impact on stomatal function and whole plant physiology.
Right heart failure considerations in pediatric ventricular assist devices
Authors: Law Sabrina P. , Morales David L. S. , Si Ming‐Sing , Friedland‐Little Joshua M. , Joong Anna , Bearl David W. , Bansal Neha , Sutcliffe David L. , Philip Joseph , Mehegan Mary , Simpson Kathleen E. , Conway Jennifer , Peng David M. ,   the ACTION Learning Network
Published: March 2021

Right heart failure (RHF) is a vexing problem in children after left ventricular assist device (LVAD) implantation that can negatively impact transplant candidacy and survival. Anticipation, prevention, early identification and appropriate medical and device management of RHF are important to successful LVAD outcomes. However, there is limited pediatric evidence to guide practice. This pediatric‐focused review summarizes the relevant literature and describes the harmonized approach to RHF from the Advanced Cardiac Therapies Improving Outcomes Network (ACTION). This review seeks to improve RHF outcomes through the sharing of best practices and experience across the pediatric VAD community.
Product Decoys: A Supply Chain Perspective
Authors: Zheng Quan , Pan Xiajun Amy , Vakharia Asoo J.
Published: March 2021

Conventional wisdom suggests that by including a decoy product in the choice set for consumers, a firm can drive consumers to select more profitable non‐decoy products. Explanations offered to explain such outcomes are rooted in the psychology of consumer behavior. A scan of retail practice, however, indicates that decoys might also be included in a product assortment for economic reasons. For example, products with very low sales potential are often included in offerings by bricks‐and‐mortar and online retailers. This leads us to investigate and offer an alternative supply side explanation for the presence of decoy products in a supply chain. More specifically, we show that in a distribution channel with multiple asymmetric manufacturers and a single retailer, there exists the possibility of an equilibrium which includes a decoy product. Such an equilibrium is characterized by the retailer stocking positive quantities of products from a subset of low‐cost manufacturers (active manufacturers) and negligible or even zero stock of a decoy product sourced from a higher cost manufacturer. The retailer includes a decoy product in the assortment since it helps to obtain better contractual terms from the active manufacturers. Recognizing this, upstream active manufacturers not only compete for market share but are also induced to cooperate (in setting wholesale prices) so as to ensure that the manufacturer of the decoy product is driven out of the market. We also find that the degree of product substitutability moderates which manufacturer's product is a decoy. Our findings provide theoretical support for industry practice as well as implications for retail assortment decisions.
Response of growth, photosynthetic electron transfer, and chloroplast ultrastructure to different LED light combination in green onion (Allium fistulosum L.)
Authors: Gao Song , Liu Xuena , Liu Ying , Cao Bili , Chen Zijing , Xu Kun
Published: March 2021

With the rapid development of facility agriculture, it has become popular to study the influences of different light qualities on the growth, material metabolism, and morphology of horticultural crops. Last several years, green onions cultivation models have undergone major changes, and facility cultivation has developed rapidly. To determine the impact of light quality on the green onions, we studied the parameters connected to photosynthesis, incorporating growth, and development, photosynthetic rate (Pn), chlorophyll fluorescence, light response curve, photosynthetic electron transfer, and chloroplast ultrastructure. We roundly analyzed the influences of different LED light combination (white: W, white‐blue combination 3:1:WB, white‐green combination 3:1:WG, white‐yellow combination 3:1:WY, and white‐red combination 3:1:WR, light intensity: 500 ± 10 μmol photons m−2 s−1) on the photosynthetic performance of green onions. The WB light led to better results than those of the WR, WG, and WY. There were significant performance improvements in leaf area, plant height, stem thickness, relative growth rate (RGR), pigment content, photosynthetic capacity, photosynthetic electron transfer efficiency, and chloroplast ultrastructure integrity. In contrast, plants treated with WG and WY were exposed to appreciably blocked light, but they effectively formed a light protection mechanism. The results of this research not only provided insight into the response mechanism of crop photosynthesis to different light qualities, but they also provided a scientific foundation for better planting green onions.
The novel HLA‐DPA1 allele, HLA‐DPA1*04:03, first described in a Brazilian individual
Authors: Vianna Romulo , Lopes Giovanna , Secco Danielle , Porto Luís Cristóvão
Published: March 2021

The novel HLA‐DPA1*04:03 allele, first described in a potential bone marrow donor from Brazil.
Consumo de alcohol en mujeres universitarias del Sur del Estado de Veracruz, México
Authors: Cortaza Ramírez Leticia , Blanco Enríquez Francisca Elvira
Published: March 2021

Introducción: el consumo de alcohol en las mujeres es una problemática cada día mayor, debido al aumento en los patrones nocivos y la edad a la que inician el consumo, por lo que representa un tema de vital relevancia en la agenda de la salud pública mundial. Objetivo: identificar el consumo de alcohol en mujeres universitarias del Sur del Estado de Veracruz, México. Método: estudio cuantitativo, descriptivo y transversal. Participaron 229 mujeres estudiantes de una universidad tecnológica de la zona sur del estado de Veracruz México, seleccionadas mediante muestreo probabilístico aleatorio simple, estratificado. Se utilizó un instrumento de recolección de datos personales y el Test de Identificación de los Trastornos debidos al Consumo de Alcohol (Audit). Resultados: se identificó que la media de edad de inicio de consumo fue de 17.1 años, 55.8% de las participantes refirieron consumo de alcohol en el último año, la bebida preferida fue la cerveza (27%), 67.2% de las universitarias tiene consumo de bajo riesgo, 27.3% consumo de riesgo, 4.7% consumo perjudicial y 0.8% consumo dependiente. Las estudiantes de Ingeniería Química Industrial reportan mayor consumo de riesgo (11.7%), perjudicial (1.6%) y dependiente (0.8%). Conclusiones: más de la mitad de las participantes reportaron ingerir bebidas alcohólicas, con patrones de consumo de riesgo, mostrando la vulnerabilidad en la que se encuentran para adoptar conductas que ponen en riesgo su salud.
A Mesh Reduction Approach to Parametric Surface Polygonization
Authors: Khan M. Asif , Vance Judy M.
Published: March 2021

Surface polygonization is the process by which a representative polygonal mesh of a surface is constructed for rendering or analysis purposes. This work presents a new surface polygonization algorithm specifically tailored to be applied to a large class of models which are created with parametric surfaces. This method has particular application in the area of building virtual environments from computer-aided-design (CAD) models. The algorithm is based on an edge reduction scheme that collapses two vertices of a given polygon edge onto one new vertex. A two step approach is implemented consisting of boundary edge reduction followed by interior edge reduction. A maximin optimization is used to determine the location of the new vertex. The concept of a visible region as the location space of the new vertex is introduced.

The method presented here differs from existing methods in that it takes advantage of the fact that for many models, the exact surface representation of the model is known before the polygonization is attempted. Because the precise surface definition is known, a maximin optimization procedure, that uses the surface information, can be used to locate the new vertex. The algorithm attempts to overcome the deficiencies in existing techniques while minimizing the number of polygons required to represent a surface and still maintaining surface integrity in the rendered model. This paper presents the algorithm and testing results.
A Genetic Design Methodology for Structure Configuration
Authors: Roston Gerald P. , Sturges Robert H.
Published: March 2021

Human designers and optimization codes are very good at improving the performance of existing designs, however, due to time and resource constraints, human designers tend to limit the range of alternative configurations considered. This paper presents a methodology, called Genetic Design (GD), to aid the designer by generating viable design alternatives. GD uses formal grammars for artifact description and representation, evaluates the artifacts automatically and manipulates the representations with genetic programming-like operations. GD can explore a wide breadth of the available design space, though at shallow depth, and presents alternatives to the human designer. The combination of GD’s ability to explore the design space and the human engineer’s ability to optimize existing configurations, promotes the production of viable, new design concepts by avoiding the inefficiencies associated with trial and error methods. This paper explores one application of GD: the design of simple truss bridges.
A General Design Program Based on Genetic Algorithms With Applications
Authors: Kalker Cornelia M. , Offermans Marcel F.
Published: March 2021

When designing constructions, a number of decisions must be made as to types of constructions, values of geometric or other design variables, choices of materials and selection of standard values. These decisions are often based on conflicting requirements. In the present paper, a genetic algorithm is proposed for finding an optimal solution for those problems.

The genetic algorithm has been implemented in an interactive program. The problem is formulated in terms of design parameters and relations (equalities, inequalities or procedures) between them. This information is parsed by a preprocessor and results in a problem definition that can be optimized with the genetic algorithm.

During the optimization, the process can be followed and controlled by the designer. The values of all design parameters can be monitored, search intervals can be changed and parameters of the algorithm modified. All this speeds up the algorithm and improves the designer’s insight in the problem.

As an example the design of navigation locks is treated.
Construction of a CAD Model From 3D Homogenization Output
Authors: Marsan Anne L. , Dutta Deba
Published: March 2021

A homogenization method has been recently developed to optimize the topology of a structure. This method will suggest a structural topology, but the results will be in a discretized, finite element form. Most engineering applications, however, require smooth structures, whether the faces of the structures be planar or curved. Given the topology of a three-dimensional structure as suggested by the homogenization method, an algorithm is developed to interpret the structure and generate a smooth, manufacturable surface representation of the structure. Some steps of the algorithm require designer inputs. An example is given which demonstrates this algorithm.
Illustration of Bilevel Formulations in Concurrent Design Modeling
Authors: Badhrinath K. , Rao J. R. Jagannatha
Published: March 2021

Multi-player mathematical games can potentially be very useful modeling tools in concurrent design. The purpose of this paper is to illustrate a variety of concurrent decision-making models that arise in two simple applications where explicit models can be obtained to represent the typical stages of design and manufacturing in product development. The resulting models are bilevel formulations and have the interpretation of a Stackelberg game between two players. The solutions in these models show that while a rich class of concurrent designs are obtained, such bilevel models also lead to different types of singularities in their solution sets.
Micromechanical Modeling of Composites Fracture
Authors: Kobelev V.
Published: March 2021

The paper considers the new micromechanical models of fracture of fiber-reinforced composites. The main emphasis is made on the determination of the exact analytical solutions of appearing fracture problems, which allow derivation of the closed functional formulas for limit fracture stresses. These expressions are suited for subsequent use in the formulations of optimal design problems. The model presented here describes the deformation and tearing of cloth. The material under study is made up of two families of orthogonal fibers. The object of investigation is the distribution of stresses in the neighborhood of the end of a semi-infinite tear. The description of the stress-strain state in the neighborhood of the end of the tear reduces to the solution of a mixed boundary-value problem for an infinite system of difference equations. When cast in terms of generating functions for an infinite vector of unknowns, the problem reduces to a RIEMANN-HELBERT problem. The analytical solution to the problem shows that the character of tearing of the material depends critically on the stresses in the fibers parallel to the direction of the tear: if the fibers parallel to the tear are stretched, then a finite rip in the material has an elliptical shape and the asymptotic behavior of the stresses around the end of the tear is similar to behavior of a solid elastic body with a crack. Conversely, if there is no stretching of the fibers parallel to the tear, then the sides of the tear intersect at a right angle, and the first unbroken fiber bears a considerably larger load than when stresses in parallel fibers are absent.
A Shape Annealing Approach to Optimal Truss Design With Dynamic Grouping of Members
Authors: Shea Kristina , Cagan Jonathan , Fenves Steven J.
Published: March 2021

A shape annealing approach to truss topology design considering the tradeoff between the mass of a structure and multiple members of the same size, called a class of members, is presented. The problem of optimal grouping involves finding a structural design with an optimal number of classes and the optimal sizes of those classes; cross-sectional area is considered as the measure of size in this paper. Multiple members of a uniform cross-sectional area is advantageous when considering the cost of purchasing and fabricating materials to build a structure. The shape annealing method (Reddy and Cagan 1994) is used as an approach to solve this problem by incorporating a method for dynamic grouping of members into classes and adding a constraint for the number of allowable classes. This method is demonstrated on arch and truss problems. As well, results from an imposed symmetry constraint for the truss problem will be shown.
Topology Optimization With Multiple Constraints
Authors: Yang R. J.
Published: March 2021

Topology optimization is used for determining the best layout of structural components to achieve predetermined performance goals. The density method which uses material density of each finite element as the design variable is employed. Unlike the most common approach which uses the optimality criteria methods, the topology design problem is formulated as a general optimization problem and is solved by the mathematical programming method. One of the major advantages of this approach is its generality; thus it can solve various problems, e.g. multi-objective and multi-constraint problems. In this study, the structural weight is chosen as the objective function and structural responses such as the compliances, displacements, and the natural frequencies are treated as the constraints. The MSC/NASTRAN finite element code is employed for response analyses. One example with four different optimization formulations was used to demonstrate this approach.
An Algorithm for Automated Design Variable Selection in Structural Shape Optimization With Intrinsically Defined Geometry
Authors: Widmann James M. , Sheppard Sheri D.
Published: March 2021

A major difficulty encountered in the shape optimization of structural components is the selection of an adequate set of shape design variables. The quality of the solution and the value of the optimal objective function depend on the chosen set of design variables. This paper presents an algorithm for the automated selection of intrinsically defined design variables to solve two-dimensional structural shape optimization problems. The algorithm arrives at a sufficient set of design variables by solving a series of optimization problems. Using the results of intermediate solutions, the algorithm adaptively refines the set of design variables until the solution converges. The algorithm specifies the addition and deletion of design variables and makes use of a model compatibility constraint to determine whether the analysis model must be updated. Two examples are presented which illustrate the effectiveness of the algorithm.
Computerized Design and Generation of Cycloidal Gearing
Authors: Litvin Faydor L. , Feng Pin-Hao
Published: March 2021

The generation and design of cycloidal (trochoidal) gearing that have found application in Wankel engines, and Root’s blowers and pumps are considered.

The following topics will be covered: (i) the generation and geometry of planar cycloidal gearing and rotors of screw Root’s blowers, and (ii) an improved design that avoids profile and surface singularities.

Computer programs have been developed that support the proposed analytical solutions.

The developed theory is illustrated with examples.
Computerized Design and Generation of a Helical Gear Drive in Substitution of a Worm-Gear Drive
Authors: Litvin Faydor L. , Kim David H.
Published: March 2021

The design and generation of a gear drive formed by an involute helical gear and an involute worm is considered. Such a drive is applied as a low-power one in substitution of a conventional worm-gear drive.

The authors have developed the geometry of the drive, simulated the meshing and contact via a computer program, and have developed the design of the grinding (cutting) wheel for generation of the worm.

A numerical example is provided for illustration of the developed theory.
Computer Aided Collision Control Using Extended Octree Representations
Authors: Bao Zhuojun
Published: March 2021

In this paper a new method for the computer aided collision control between moving bodies is presented. A dynamic and continuous collision control is reduced to static testes by subdividing a given time interval into sufficingly small pieces and the introduction of an effective space (domain) of a moving body for each time interval. Using the recursive hierarchical exdended octree representations the intersection of a body with the effected space of another moving body is reduced to the distance determination between nodes (cubes) of extended octrees. The use of the exdended octree representations leads to a quick elimination of non-relevant nodes. In case of a possible collision the collision zone can be recognized and presented by the intersection between relevant nodes using analytic tests. For this, both a discrete and a continuous collision control are developed. The proposed method is useful for the collision control in robotics, mechanics, manufacturing and assembling process.
Trajectory Generation for High-Speed Machinery With Minimal Residual Vibration Using Low-Harmonic Rational Curves
Authors: Ge Q. J. , Rastegar J.
Published: March 2021

For a given high-speed machinery, a significant source of the internally induced vibrational excitation is the presence of high frequency harmonics in the trajectories that the system is forced to follow. We develop a method for synthesizing a low-harmonic joint trajectory to reduce the potential vibration and related control problems using low-harmonic rational curves. Continuity conditions for these curves are studied and are used to develop a geometric algorithm for designing low-harmonic rational spline curves. Finally, we discuss how these low-harmonic curves may be used for trajectory generation of high-speed machinery with minimal residual vibration.
Contact Stress Analysis in Ball Screw Mechanism Using the Tubular Medial Axis Representation of Contacting Surfaces
Authors: Huang Huai-Te T. , Ravani Bahram
Published: March 2021

A simple method is presented for analysis of contact stresses and deformation conditions between the bearing balls, screw, and nut of the Ball Screw Mechanism. The method is based on representation of contact geometry and curvature analysis of contacting surfaces using a generalization of Medial Axis Transform (MAT) to tubular surfaces developed in this paper. Simplified Hertzian contact solutions are obtained using the curvature relationship in MAT. The results are approximate but do include the effect of complex thread profiles as a result of the helical grooves and are suitable for mechanical design purposes.
A Geometric Inspection of Two 3-R Robots Manipulating a Four-Bar Linkage Payload: The Velocity Problems
Authors: Mattson Keith G. , Pennock Gordon R.
Published: March 2021

This paper presents solutions to the forward and inverse velocity problems of two planar three-degree-of-freedom robots, with all revolute joints, manipulating a planar four-bar linkage payload. These kinematic problems are formulated in terms of two Jacobian matrices: one associated with the independent inputs to the robots, and the other associated with the payload outputs. The paper emphasizes how both Jacobian matrices can be obtained from a geometric inspection of the system. This provides kinematic insight into the system and is believed to be important in the design and control of cooperating robot workcells. The paper also shows that the inverse of the Jacobian matrix associated with the independent inputs can be obtained directly from inspection. The inverse of the Jacobian matrix associated with the outputs is obtained from geometric inspection by considering a four-input mechanism equivalent to the passive part of the system. Choosing one input at a time, the instantaneous centers of zero velocity provide relationships between the outputs of the mechanism and each input. The matrix is then formulated from these relationships using the principle of superposition of the outputs. The paper also presents the singular and stationary configurations associated with the system and emphasizes the geometric interpretation of these configurations. For illustrative purposes, a numerical example is included which shows how singular and stationary configurations effect the solutions to the velocity problems.