bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy and Safety of Robot‐Assisted Drilling Decompression for Osteonecrosis of the Femoral Head
Authors: Luo Jin , Yan Ya‐jing , Wang Xiao‐dong , Long Xu‐dong , Lan Hai , Li Kai‐nan
Published: May 2020

Objective

To investigate the safety and superiority of robot‐assisted femoral head drilling decompression in the treatment of femoral head necrosis.

Methods

A total of 63 patients who underwent borehole decompression of the femoral head in our hospital from January 2016 to March 2019 were recruited. Patients were divided into two groups for comparison according to surgical methods. In the robot‐assisted surgery group, there were 30 cases with 41 femoral heads. The conventional group had 33 cases and 46 femoral heads. All patients signed the consent form before the operation. The follow‐up time was 6 months. The incision lengths, operation times, intraoperative blood loss, intraoperative fluoroscopies, guide needle punctures, postoperative Harris scores, and postoperative complications of the two groups were compared.

Results

The incision length of the robot surgery group was 5.16 ± 0.41 cm, while that of the traditional surgery group was 7.42 ± 0.50 cm. The operation time of the robot surgery group was 46.99 ± 4.94 min, while that of the traditional surgery group was 55.01 ± 6.19 min. The fluoroscopy frequency of the robot surgery group was 10.50 ± 1.78 times, while that of the traditional surgery group was 17.91 ± 2.20 times. The intraoperative blood loss in the robotic surgery group was 20.62 ± 2.52 mL, while that in the conventional surgery group was 52.72 ± 3.39 mL. In the robot operation group, each femoral head guide needle was punctured three times, and the puncture was successful one time. The number of guided needle punctures in the traditional group was 8.02 ± 1.73. The difference between the two groups was statistically significant (P < 0.05). The Harris score was 69.53 ± 7.51 in the robot surgery group and 68.38 ± 7.26 in the traditional surgery group one month after surgery, 78.52 ± 6.49 in the robot surgery group and 76.41 ± 7.95 in the traditional surgery group three months after surgery, and 83.32 ± 8.62 in the robot surgery group and 81.74 ± 6.20 in the traditional surgery group six months after surgery. There was no significant difference between the two groups (P > 0.05). In the traditional group, there was one case of incision infection and one case of femoral head collapse during follow‐up. In the robot group, there were no complications, such as incision infection and deep vein thrombosis. No collapse of the femoral head was found in the robot group during follow‐up.

Conclusion

The positioning system of the orthopaedic robot is an ideal method for the treatment of femoral head necrosis. This method has the advantages of simple operation, accurate drilling, a short operation time, less surgical trauma, less radioactivity, and good recovery of hip joint function.
Clustered cases of acral perniosis: Clinical features, histopathology, and relationship to COVID‐19
Authors: Cordoro Kelly M. , Reynolds Sean D. , Wattier Rachel , McCalmont Timothy H.
Published: May 2020

Background/Objectives

A recent marked increase in pediatric and adult patients presenting with purpuric acral lesions concerning for ischemia, thrombosis and necrosis has been observed in COVID‐19 prevalent regions worldwide. The clinical and histopathological features and relationship to COVID‐19 have not been well described. The objective of this case series is to describe the clinical features and determine the histopathologic findings and clinical implications of the clusters of acral perniosis cases identified in pediatric patients.

Methods

We describe six otherwise healthy adolescents—three siblings per family from two unrelated families—presented within a 48‐hour period in April, 2020, with acral perniosis‐like lesions in the context of over 30 similar patients who were evaluated within the same week.

Results

Affected patients had mild symptoms of viral upper respiratory infection (URI) or contact with symptomatic persons 1‐2 weeks preceding the rash. They all presented with red to violaceous macules and dusky, purpuric plaques scattered on the mid and distal aspects of the toes. Skin biopsies performed on each of the six patients demonstrated near identical histopathologic findings to those of idiopathic perniosis, with a lymphocytic inflammatory infiltrate without evidence of thromboembolism or immune complex vasculitis. While SARS‐CoV‐2 polymerase chain reaction was negative, testing was performed 1‐2 weeks after URI symptoms or sick contact exposure.

Conclusion

We offer a clinical approach to evaluation of patients with this presentation and discuss the possibility that these skin findings represent a convalescent‐phase cutaneous reaction to SARS‐CoV‐2 infection.
Policy Analysis and Political Sustainability
Authors: Patashnik Eric M. , Weaver R. Kent
Published: May 2020

Policies usually have to be sustained for a substantial period of time to have their intended impact, but they may face a number of important political challenges after enactment that can result in their repeal or erosion. These challenges follow recurrent patterns and frequently can be predicted in advance, at least in their broad parameters. Policy analysts should, therefore, consider political sustainability as an important criterion in designing policies and evaluating policy alternatives. Drawing on research on the ways that policies create self‐reinforcing and self‐undermining feedbacks, this article provides a “checklist” of potential sources, risk factors, and warning signs for potential challenges to political sustainability. It also identifies and discusses a set of strategies that both program defenders and challengers can use to achieve their objectives. The article applies this analysis to the case of the Affordable Care Act.
The use of spatially patterned methods for vegetation restoration and management across systems
Authors: Shaw Julea A. , Roche Leslie M. , Gornish Elise S.
Published: May 2020

Widespread degradation of natural lands has created an urgent need for restoration. However, the high cost of conventional techniques limits the extent and success of restoration efforts. As a result, practitioners have developed new cost‐effective techniques. Spatially patterned restoration methods, where established clusters of plant species serve as propagule sources across a broad target area, have been proposed as practical restoration techniques. The spatial patterning is expected to reduce initial costs and provide ecological benefits such as increasing habitat heterogeneity. Over the past three decades, multiple spatially patterned restoration methods have emerged around the globe; however, it is unclear whether applications and theoretical foundations have been connected across methods. We conducted a literature review and bibliometric network analyses to (1) examine patterns in focal study systems, cost‐effectiveness, and ecological outcomes for spatially patterned restoration methods and (2) analyze connectivity among the bodies of literature associated with common spatially patterned restoration methods to identify knowledge gaps and synergies. We found the three most commonly studied methods are applied nucleation, slot seeding, and strip seeding. Applied nucleation studies mainly occurred in tropical forests and emphasized plant diversity and seed‐dispersing animal visitation. Slot‐seeding and strip‐seeding studies both primarily occurred in temperate grasslands and emphasized plant establishment and production. Applied nucleation and slot‐seeding approaches had distinct theoretical bases, as evidenced by patterns in reference citation, while strip‐seeding approaches did not draw from a unified body of literature. We discuss the need for full economic analyses and theoretical links between the different methods.
Do vertical spillovers differ by investors’ productivity? Theory and evidence from Vietnam
Authors: Ni Bin , Kato Hayato
Published: May 2020

Developing countries are eager to host foreign direct investment to receive positive technology spillovers to their local firms. However, what types of foreign firms are desirable for the host country to achieve spillovers best? We address this question using firm‐level panel data from Vietnam to investigate whether foreign Asian investors in downstream sectors with different productivity affect the productivity of local Vietnamese firms in upstream sectors differently. Using endogenous structural breaks, we divide Asian investors into low‐, middle‐, and high‐productivity groups. The results suggest that the presence of the middle group has the strongest positive spillover effect. The differential spillover effects can be explained by a simple model with vertical linkages and productivity‐enhancing investment by local suppliers. The theoretical mechanism is also empirically confirmed.
Examining preservice teachers' responses to area conservation tasks
Authors: Hong Dae S. , Runnalls Cristina
Published: May 2020

The purpose of this work was to explore how elementary preservice teachers responded to area conservation tasks. We administered written pre‐assessments, followed by semi‐structured interviews with 23 preservice teachers, asking them to respond to and reason with area conservation tasks. Findings highlighted several interesting preservice teachers' struggles when assessing area conservation tasks. In many cases, preservice teachers exhibited struggles similar to students, especially with regards to the justification of their area conservation claims. We provide recommendations to assist preservice teachers in their development of mathematical content knowledge in their teacher education programs, so that in the future they may better plan area lessons that promote procedural fluency from conceptual understanding in area measurement.
Functional redundancy between flavodiiron proteins and NDH‐1 in Synechocystis sp. PCC 6803
Authors: Nikkanen Lauri , Santana Sánchez Anita , Ermakova Maria , Rögner Matthias , Cournac Laurent , Allahverdiyeva Yagut
Published: May 2020

In oxygenic photosynthetic organisms, excluding angiosperms, flavodiiron proteins (FDPs) catalyze light‐dependent reduction of O2 to H2O. This alleviates electron pressure on the photosynthetic apparatus and protects it from photodamage. In Synechocystis sp. PCC 6803, four FDP isoforms function as hetero‐oligomers of Flv1 and Flv3 and/or Flv2 and Flv4. An alternative electron transport pathway mediated by the NAD(P)H dehydrogenase‐like complex (NDH‐1) also contributes to redox hemostasis and the photoprotection of photosynthesis. Four NDH‐1 types have been characterized in cyanobacteria: NDH‐11 and NDH‐12, which function in respiration; and NDH‐13 and NDH‐14, which function in CO2 uptake. All four types are involved in cyclic electron transport. Along with single FDP mutants (∆flv1 and Δflv3) and the double NDH‐1 mutants (∆d1d2, which is deficient in NDH‐11,2 and ∆d3d4, which is deficient in NDH‐13,4), we studied triple mutants lacking one of Flv1 or Flv3, and NDH‐11,2 or NDH‐13,4. We show that the presence of either Flv1/3 or NDH‐11,2, but not NDH‐13,4, is indispensable for survival during changes in growth conditions from high CO2/moderate light to low CO2/high light. Our results show functional redundancy between FDPs and NDH‐11,2 under the studied conditions. We suggest that ferredoxin probably functions as a primary electron donor to both Flv1/3 and NDH‐11,2, allowing their functions to be dynamically coordinated for efficient oxidation of photosystem I and for photoprotection under variable CO2 and light availability.
CaMKII activity contributes to homeometric autoregulation of the heart: A novel mechanism for the Anrep effect
Authors: Reil Jan‐Christian , Reil Gert‐Hinrich , Kovács Árpád , Sequeira Vasco , Waddingham Mark T. , Lodi Maria , Herwig Melissa , Ghaderi Shahrooz , Kreusser Michael M. , Papp Zoltán , Voigt Niels , Dobrev Dobromir , Meyhöfer Svenja , Langer Harald F. , Maier Lars S. , Linz Dominik , Mügge Andreas , Hohl Mathias , Steendijk Paul , Hamdani Nazha
Published: May 2020

Key points

The Anrep effect represents the alteration of left ventricular (LV) contractility to acutely enhanced afterload in a few seconds, thereby preserving stroke volume (SV) at constant preload. As a result of the missing preload stretch in our model, the Anrep effect differs from the slow force response and has a different mechanism.

The Anrep effect demonstrated two different phases. First, the sudden increased afterload was momentary equilibrated by the enhanced LV contractility as a result of higher power strokes of strongly‐bound myosin cross‐bridges. Second, the slightly delayed recovery of SV is perhaps dependent on Ca2+/calmodulin‐dependent protein kinase II activation caused by oxidation and myofilament phosphorylation (cardiac myosin‐binding protein‐C, myosin light chain 2), maximizing the recruitment of available strongly‐bound myosin cross‐bridges.

Short‐lived oxidative stress might present a new facet of subcellular signalling with respect to cardiovascular regulation.

Relevance for human physiology was demonstrated by echocardiography disclosing the Anrep effect in humans during handgrip exercise.

The present study investigated whether oxidative stress and Ca2+/calmodulin‐dependent protein kinase II (CaMKII) activity are involved in triggering the Anrep effect. LV pressure–volume (PV) analyses of isolated, preload controlled working hearts were performed at two afterload levels (60 and 100 mmHg) in C57BL/6N wild‐type (WT) and CaMKII‐double knockout mice (DKOCaMKII). In snap‐frozen WT hearts, force–pCa relationship, H2O2 generation, CaMKII oxidation and phosphorylation of myofilament and Ca2+ handling proteins were assessed. Acutely raised afterload showed significantly increased wall stress, H2O2 generation and LV contractility in the PV diagram with an initial decrease and recovery of stroke volume, whereas end‐diastolic pressure and volume, as well as heart rate, remained constant. Afterload induced increase in LV contractility was blunted in DKOCaMKII‐hearts. Force development of single WT cardiomyocytes was greater with elevated afterload at submaximal Ca2+ concentration and associated with increases in CaMKII oxidation and phosphorylation of cardiac‐myosin binding protein‐C, myosin light chain and Ca2+ handling proteins. CaMKII activity is involved in the regulation of the Anrep effect and associates with stimulation of oxidative stress, presumably starting a cascade of CaMKII oxidation with downstream phosphorylation of myofilament and Ca2+ handling proteins. These mechanisms improve LV inotropy and preserve stroke volume within few seconds.
Field emission scanning probe lithography with GaN nanowires on active cantilevers
Authors: Behzadirad Mahmoud , Rishinaramangalam Ashwin K. , Feezell Daniel , Busani Tito , Reuter Christoph , Reum Alexander , Holz Mathias , Gotszalk Teodor , Mechold Stephan , Hofmann Martin , Ahmad Ahmad , Ivanov Tzvetan , Rangelow Ivo W.
Published: May 2020

Field emission scanning probe lithography (FE-SPL) is based on the exposure of a resist covered substrate with low energy electrons emitted from an ultra-sharp tip placed in close vicinity to a sample. GaN nanowires (NWs) present high mechanical stability, suitable geometry for FE-SPL, and controllable electrical properties achieved by adjusting dopant concentration. Here, the authors will present long time exposure results performed using GaN NWs tips, mounted on active scanning probes, working as field electron emitters. Using GaN NW tips, features down to the sub-10 nm were achieved in the FE-SPL process. A systematic study of the field emission current stability, exposure reproducibility, and results on exemplary high-resolution exposure and nanostructure imaging done with the same GaN tips will also be presented.
Framing Social Comparison Feedback With Financial Incentives for Physical Activity Promotion: A Randomized Trial
Authors: Patel Mitesh S. , Asch David A. , Rosin Roy , Small Dylan S. , Bellamy Scarlett L. , Hoffer Karen , Shuttleworth David , Hilbert Victoria , Zhu Jingsan , Yang Lin , Wang Xingmei , Volpp Kevin G.
Published: May 2020

Background: Social comparison feedback is often used in physical activity interventions but the optimal design of feedback is unknown.Methods: This 4-arm, randomized trial consisted of a 13-week intervention period and 13-week follow-up period. During the intervention, 4-person teams were entered into a weekly lottery valued at about $1.40/day and contingent on the team averaging ≥7000 steps per day. Social comparison feedback on performance was delivered weekly for 26 weeks, and varied by reference point (50th vs 75th percentile) and forgiveness in use of activity data (all 7 d or best 5 of 7 d). The primary outcome was the mean proportion of participant-days achieving the 7000-step goal.Results: During the intervention period, the unadjusted mean proportion of participant-days that the goal was achieved was 0.47 (95% confidence interval [CI]: 0.38 to 0.56) in the 50th percentile arm, 0.38 (95% CI: 0.30 to 0.37) in the 75th percentile arm, 0.40 (95% CI: 0.31 to 0.49) in the 50th percentile with forgiveness arm, and 0.47 (95% CI: 0.38 to 0.55) in the 75th percentile with forgiveness arm. In adjusted models during the intervention and follow-up periods, there were no significant differences between arms.Conclusions: Changing social comparison feedback did not impact physical activity.
Don Hellison’s Scholarship Reconsidered
Authors: Wright Paul M. , Fuerniss Karisa , Cutforth Nicholas
Published: May 2020

Purpose: Don Hellison’s scholarship made a lasting impact on the academic literature, policy, and practice of physical education and sport pedagogy. In this essay, we summarize and interpret Don’s perspective on scholarship, his own work, and the literature that it spawned.Method: Don’s work, published and unpublished, as well as the rapidly expanding body of teaching personal and social responsibility literature was analyzed using Boyer’s comprehensive framework for scholarship reconsidered.Results: Don was a strong advocate for broader definitions of scholarship in kinesiology, whose work integrated the scholarship of discovery, integration, application, and teaching. This influence remains evident in the teaching personal and social responsibility literature.Discussion/Conclusions: Amid calls for broader and more flexible definitions of scholarship in higher education, Don was a role model who demonstrated what is possible in this regard in the field of kinesiology.
Ancestral Resurrection and Directed Evolution of Fungal Mesozoic Laccases
Authors: Gomez-Fernandez Bernardo J. , Risso Valeria A. , Rueda Andres , Sanchez-Ruiz Jose M. , Alcalde Miguel
Published: May 2020

The broad variety of biotechnological uses of fungal laccases is beyond doubt (food, textiles, pulp and paper, pharma, biofuels, cosmetics, and bioremediation), and protein engineering (in particular, directed evolution) has become the key driver for adaptation of these enzymes to harsh industrial conditions. Usually, the first requirement for directed laccase evolution is heterologous expression, which presents an important hurdle and often a time-consuming process. In this work, we resurrected a fungal Mesozoic laccase node which showed strikingly high heterologous expression and pH stability. As a proof of concept that the ancestral laccase is a suitable blueprint for engineering, we performed a quick directed evolution campaign geared to the oxidation of the β-diketone 1,3-cyclopentanedione, a poor laccase substrate that is used in the polymerization of vinyl monomers.
A Forgotten Episode of Marburg Virus Disease: Belgrade, Yugoslavia, 1967
Authors: Ristanović Elizabeta S. , Kokoškov Nenad S. , Crozier Ian , Kuhn Jens H. , Gligić Ana S.
Published: May 2020

In 1967, several workers involved in poliomyelitis vaccine development and production fell ill at three different locations in Europe with a severe and often lethal novel disease associated with grivets (Chlorocebus aethiops) imported from Uganda. This disease was named Marburg virus disease (MVD) after the West German town of Marburg an der Lahn, where most human infections and deaths had been recorded. Consequently, the Marburg episode received the most scientific and media attention.
Vaccine Candidate Brucella melitensis 16M
ΔvjbR
Is Safe in a Pregnant Sheep Model and Confers Protection
Authors: Hensel Martha E. , Garcia-Gonzalez Daniel G. , Chaki Sankar P. , Hartwig Airn , Gordy Paul W. , Bowen Richard , Ficht Thomas A. , Arenas-Gamboa Angela M.
Published: May 2020

Brucellosis is one of the most commonly reported zoonotic disease with a worldwide distribution. Of the 12
Brucella
species,
Brucella melitensis
is considered the most virulent and causes reproductive failure (abortions/stillbirths) in small ruminants, which can spread the disease to other animals or to humans. Vaccination of small ruminants is a key measure used to protect both human and animal health. However, the commercially available live-attenuated vaccine for
Brucella melitensis
Rev. 1 retains virulence and can cause disease in animals and humans. In order to evaluate the safety and efficacy in sheep, we vaccinated pregnant sheep with 16M
ΔvjbR
. Our results indicate that 16M
ΔvjbR
was safer for use during pregnancy, provided a similar level of protection as Rev. 1, and could be considered an improved candidate for future vaccine trials.
Can Unconventional Immunomodulatory Agents Help Alleviate COVID-19 Symptoms and Severity?
Authors: Mamber Stephen W. , Krakowka Steven , Osborn Jeffrey , Saberski Lloyd , Rhodes Ryan G. , Dahlberg Albert E. , Pond-Tor Sunthorn , Fitzgerald Kara , Wright Neal , Beseme Sarah , McMichael John
Published: May 2020

Severe acute respiratory syndrome coronavirus 2 (SARS coronavirus 2, or SARS-CoV-2) is the cause of the respiratory infection known as COVID-19. From an immunopathological standpoint, coronaviruses such as SARS-CoV-2 induce increased levels of a variety of T-helper 1 (Th1) and inflammatory cytokines and chemokines, including interleukin-1 (IL-1), IL-6, CCL2 protein, and CXCL10 protein. In the absence of proven antiviral agents or an effective vaccine, substances with immunomodulatory activity may be able to inhibit inflammatory and Th1 cytokines and/or yield an anti-inflammatory and/or Th2 immune response to counteract COVID-19 symptoms and severity.
The genesis of a giant mud canopy by catastrophic failure of a thick evaporite sealing layer
Authors: Kirkham Chris , Cartwright Joe , Bertoni Claudia , Van Rensbergen Pieter
Published: May 2020

Three-dimensional seismic imaging and well calibration reveal a large allochthonous mud edifice that is composed of several mud extrusions and covers an area >740 km2 on the outer shelf slope of the Nile Delta. The allochthonous material was sourced from beneath the ∼1-km-thick Messinian evaporites in the Eastern Mediterranean and extruded synchronously as eight large mud volcanoes directly on top of the Messinian evaporites in a catastrophic remobilization event at the end of the Messinian salinity crisis. These large extrusive flows coalesced to form a single edifice with an exceptional volume of ∼292 km3 that is connected to eight widely spaced conduits. We argue that this large mud body represents a new morphological type and scale of mud extrusion. We propose that mud extrusions that coalesce on a surface forming a multi-conduit-fed edifice be referred to as mud canopies, by analogy with salt canopies, with implications for basin reconstruction, paleo–overpressure release events, and fluid migration.
Environmental land-cover classification for integrated watershed studies: Cape Bounty, Melville Island, Nunavut
Authors: Hung Jacqueline K.Y. , Treitz Paul
Published: May 2020

Thematic maps developed from remote sensing data are extremely useful for designing intensive field studies, particularly for large areas that are logistically challenging to access. The integrated watershed studies at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut, rely heavily on land cover for establishing sampling locations regardless of the type of research being conducted (e.g., permafrost degradation, greenhouse gas exchange, surface water chemistry, etc.). Here, we present an environmental land-cover classification of the CBAWO that was developed through an iterative process employing parametric and non-parametric classification algorithms applied to WorldView-2 satellite data and topographic variables. The support vector machine classification of eight-band WorldView-2 spectral data and a topographic wetness index produced the highest classification accuracy for eight land-cover classes (overall classification accuracy: 90.7%; Kappa coefficient (κ): 0.89). This analysis also provided a more precise classification scheme, particularly in the context of the relationship between vegetation type and moisture regime. The environmental land-cover classification derived will better inform future integrated studies of the watershed and allow for upscaling of site-level characteristics to the watershed-scale using the updated vegetation classes.
Could acceleration of a pulsar affect braking index?
Authors: Chang Zhe , Zhu Qing-Hua
Published: May 2020

In the coming era of multi-messenger astrophysics, pulsars might be one of the most possible electromagnetic counterparts of the gravitational wave. The braking indices, which are related closely to the electromagnetic radiation of pulsars, are shown to be larger for the pulsars with companion. It motivates us to set up a modified spin-down equation for accelerated pulsars. In this model, we attempt to figure out whether acceleration of a pulsar can cause a larger braking index.
Numerical and theoretical treatment based on the compact finite difference and spectral collocation algorithms of the space fractional-order Fisher’s equation
Authors: Khader M. M. , Adel M.
Published: May 2020

This paper presents an accurate numerical algorithm to solve the space fractional-order Fisher’s equation where the derivative operator is described in the Caputo derivative sense. In the presented discretization process, first, we use the compact finite difference (CFD) for a semi-discrete occurrence in time derivative and implement the Chebyshev spectral collocation method (CSCM) of the third-kind to discretize the spatial fractional derivative. The presented method converts the problem understudy to be a system of algebraic equations which can be easily solved. To study the convergence and stability analysis, some theorems are given with their proofs. A numerical simulation is outputted to test the accuracy and applicability of our presented algorithm.
IPO UNDERPRICING AND INFORMATION QUALITY OF PROSPECTUSES
Authors: ZHOU KUO , ZHOU BAICHENG , LIU HUAXIAO
Published: May 2020

Effective information disclosure is the cornerstone of sustainable operation of the capital market. In the IPO market, whether public information in the prospectus can be fully captured by investors largely depends on the quality of valuation-relevant information. Based on Chinese prospectuses, we create five unique indicators to measure the information quality and examine the relationship between information quality and IPO underpricing. We find that high quality of information disclosure results in less underpricing because they relieve serious information asymmetry between issuing companies and investors. We provide a new method to supervise and improve the quality of non-financial information disclosure.
Hardware-Efficient Bartlett Spectral Density Estimator Based on Optimized R22FFT Processor Using CCSSI Method
Authors: Sadaghiani Abdolvahab Khalili , Sheikhaei Samad
Published: May 2020

This paper offers a novel, low-power, hardware-efficient, yet high-frequency architecture for a power spectral density (PSD) estimator, based on the Bartlett method, for low-power biomedical applications. The Bartlett method is a nonparametric method for PSD estimation. The proposed architecture operates based on a modified multiplierless 64-point optimized radix-22single-path delay feedback (R22SDF) FFT processor. To obtain the final result, it also uses modified safe-scaling in a way that removes the need to use several extra hardware units. It takes advantage of combined coefficient selection and shift-and-add implementation (CCSSI) for computing twiddle factors which is a new algorithm based on digital computer coordinate rotation (CORDIC) for generating trigonometric values. The proposed method has the capability of operating on short word lengths (WLs). Artix-7 is the FPGA used in this research and Verilog is the language used for hardware design. For 8-bit WL and 244-mW power, a frequency of 286 MHz has been achieved. Several vital signals are used for performance comparison of the proposed technique with state-of-the-art designs.
High-Throughput, Resource-Efficient Multi-Dimensional Parallel Architecture for Space-Borne Sea-Land Segmentation
Authors: Zhang Cunguang , Jiang Hongxun , Pan Riwei , Cao Haiheng , Zhou Mingliang
Published: May 2020

Sea-land segmentation based on edge detection is commonly utilized in ship detection, coastline extraction, and satellite system applications due to its high accuracy and rapid speed. Pixel-level distribution statistics do not currently satisfy the requirements for high-resolution, large-scale remote sensing image processing. To address the above problem, in this paper, we propose a high-throughput hardware architecture for sea-land segmentation based on multi-dimensional parallel characteristics. The proposed architecture is well suited to wide remote sensing images. Efficient multi-dimensional block level statistics allow for relatively infrequent pixel-level memory access; a boundary block tracking process replaces the whole-image scanning process, markedly enhancing efficiency. The tracking efficiency is further improved by a convenient two-step scanning strategy that feeds back the path state in a timely manner for a large number of blocks in the same direction appearing in the algorithm. The proposed architecture was deployed on Xilinx Virtex k7-410t to find that its practical processing time for a [Formula: see text] remote sensing image is only about 0.4[Formula: see text]s. The peak performance is 1.625[Formula: see text]gbps, which is higher than other FPGA implementations of segmentation algorithms. The proposed structure is highly competitive in processing wide remote sensing images.
DNA origami and unknotted A-trails in torus graphs
Authors: Morse Ada , Adkisson William , Greene Jessica , Perry David , Smith Brenna , Ellis-Monaghan Jo , Pangborn Greta
Published: May 2020

Motivated by problem of determining the unknotted routes for the scaffolding strand in DNA origami self-assembly, we examine the existence and knottedness of A-trails in graphs embedded on the torus. We show that any A-trail in a checkerboard-colorable torus graph is unknotted and characterizes the existence of A-trails in checkerboard-colorable torus graphs in terms of pairs of quasitrees in associated embeddings. Surface meshes are frequent targets for DNA nanostructure self-assembly, and so we study both triangular and rectangular torus grids. We show that aside from one exceptional family, a triangular torus grid contains an A-trail if and only if it has an odd number of vertices, and that such an A-trail is necessarily unknotted. On the other hand, while every rectangular torus grid contains an unknotted A-trail, we also show that any torus knot can be realized as an A-trail in some rectangular grid. Lastly, we use a gluing operation to construct infinite families of triangular and rectangular grids containing unknotted A-trails on surfaces of arbitrary genus. We also give infinite families of triangular grids containing no unknotted A-trail on surfaces of arbitrary nonzero genus.
Measure of complexity for dynamical self-gravitating structures
Authors: Yousaf Z. , Bhatti M. Z. , Naseer T.
Published: May 2020

We consider the definition of complexity for dynamical spherically self-gravitating matter distribution in the presence of heat dissipation introduced by Herrera [L. Herrera, A. Di Prisco and J. Ospino, Phys. Rev. D 98 (2018) 104059] and generalize it in [Formula: see text] gravity, where [Formula: see text] and [Formula: see text] are the Ricci scalar and the trace of energy–momentum tensor, respectively. We measure the complexity of structure as well as pattern of evolution of the fluid distribution and examine these under the effects of dark source terms of modified gravity. Some dynamical and kinematical equations are observed in the dissipative and nondissipative cases in the background of modified theory. Finally, we discuss evolution of the structure scalars and stability of a condition where the complexity factor vanishes.
Polarization property of light scattered on dielectric nanorods at oblique incident angle
Authors: Isro Suhandoko D. , Iskandar Alexander A. , Tjia May On
Published: May 2020

We report the study of light polarization property upon scattering off a dielectric nanorod in which the direction of the incident light is at an angle with respect to the cylinder main axis. The numerical work is done on the basis of the cylindrical Mie theory. It is shown that for incident light with different polarization, the resulted scattering cross-section spectra will also show different characteristics with varying incident angles. For TE case, resonance splitting is observed due to excitation of a new resonance mode, while for TM case, resonance merging is observed. An interference effect between different resonance modes due to variation of incident angle is then resulted in suppression of backward scattering intensity for TM case. Meanwhile, for TE case, at illumination angle approaching grazing angle, a spectral range exists whereby the scattered wave’s angular intensity profile forms a perpendicular dipolar feature with different polarization. The reported results may be useful for aplication of nanoantenna, photovoltaic, and polarization conversion.
殘疾人士與倡導工作
Authors: 甘 炳光
Published: May 2020

本文主要探討殘疾人士與倡導工作的關係，指出若要打破主流社會對殘疾人士的負面定型及對殘疾的定義，社工要多反思傳統的個人或病態模式對殘疾的定義所帶來的問題。社工應要採用社會模式及社會建構殘疾的角度去看殘疾問題，將著重點由關心個人適應轉化為去改變環境，令殘疾不再被視為個人問題，反而是社會環境及社會政策出現的障礙所做成的問題。要移除和打破環境及社會政策的障礙，倡導工作是不可或缺及要積極推動的工作。要有效地協助殘疾人士推動倡導工作，社工要多採用「權利為本」及「強項為本」的工作模式。本文會重點討論倡導工作的意義和作用，以及提出倡導工作為殘疾人士帶來充權效果。
探討中學生抱負取向與職業生涯探索的關係
Authors: 崔 永康 , 張 偉良 , 譚 子豪 , 金 秋萍
Published: May 2020

本文從自我決定理論 (Self Determination Theory) 的觀點出發，探討香港中學生的抱負取向（包括外在期望及內在期望）與職業生涯探索的關係。是次研究以問卷形式進行，從10間中學總共2,122名中一至中六的學生得到有效數據。結果顯示在控制了人口因素、成績及社會支持後，學生的抱負取向與職業生涯探索有顯著的關係。對比以上各項因素，發現學生的內在期望對職業生涯探索起較大的預測作用。最後，本文會探討結果在實踐及研究的應用。

Based on Self Determination Theory, this paper explores the relationship between different aspirations (intrinsic aspirations and extrinsic aspirations) and career exploration among Hong Kong secondary school students. The sample consisted of 2,122 secondary school students from 10 secondary schools. The results found that both intrinsic and extrinsic aspirations are significant predictors of career exploration after controlling for demographic, academic results and perceived social support variables. Among the predictors examined, intrinsic aspirations explained more variance of career exploration than others. Implications of the results for theory and practice were discussed.
Detection of Structural Damage in Rotating Beams Using Modal Sensitivity Analysis and Sparse Regularization
Authors: Yang Dahao , Lu Zhong-Rong , Wang Li
Published: May 2020

Rotating beams are often encountered in the wind turbines and the rotors, and detection of the damages in rotating beams as earlier as possible is central to ensuring the safety and serviceability of practical structures. To this end, a modal sensitivity approach in conjunction with the sparse regularization is proposed in this paper. First, the eigen equations for the flap-wise and chord-wise vibrations of a rotating beam are established upon Hamilton’s principle. Then, damage detection is formulated as a nonlinear least-squares problem that finds the damage coefficients to minimize the error between the measured and calculated data. To solve the nonlinear least-squares problem, the sensitivity method that requires the modal sensitivity analysis is developed. In real applications, damage detection is usually an ill-posed problem and to circumvent the ill-posedness, the sparse regularization is introduced due to the fact that the numbers of actual damage locations are often scarce. Numerical examples are studied and results show that the proposed approach is more accurate than the enhanced sensitivity approach and the flap-wise modal data outperforms the chord-wise modal data in damage detection of rotating beams.
Simplified error bounds for turning point expansions
Authors: Dunster T. M. , Gil A. , Segura J.
Published: May 2020

Recently, the present authors derived new asymptotic expansions for linear differential equations having a simple turning point. These involve Airy functions and slowly varying coefficient functions, and were simpler than previous approximations, in particular being computable to a high degree of accuracy. Here we present explicit error bounds for these expansions which only involve elementary functions, and thereby provide a simplification of the bounds associated with the classical expansions of Olver.
The Influence of Patents on Purchase Intention Through the Technology Acceptance Model
Authors: Chang Yu-Hsin , Lai Kuei-Kuei , Yang Ming-Chung , Hsu Ya-Ting
Published: May 2020

This study aims to apply the TAM in a situation where the customers have not purchased and utilized the products. To achieve its purpose, this study adopts the perceived reliability as an internal variable, and the patent as an external variable. In the context of various levels of technological content and familiarity of consumers with technology products, this study explores whether patents give the technological image to consumers before they use a specific technology will enhance their perceived reliability, perceived usefulness, and perceived ease of use and purchase intentions. The results showed that when consumers have a low level of familiarity with high-tech products, products labeled with relevant patent information will increase consumers’ awareness of reliability, usefulness, ease of use, and purchase intention.
The Simplest Iron μ-oxo Species. The Molecular Structure of {[Fe(porphine)]2O}
Authors: Li Ming , Scheidt W. Robert
Published: May 2020

We have prepared a new [Formula: see text]-oxo iron(III) porphyrin complex based on the simplest possible porphyrin ligand, porphine. Our structure determination for {[Fe(porphine)]2O}shows that it has a decidedly different molecular structure compared to all other [Formula: see text]-oxo iron(III)porphyrin complexes with two independent porphyrin ligands. The Fe–O–Fe angle is 153.21 (16)[Formula: see text]which leads to a small interplanar angle of 22.7[Formula: see text]between the two porphine rings. This also leads to C[Formula: see text]C nonbonded contact as short as 3.35Å between the two rings. The twist angle of the two porphine rings is 16.8[Formula: see text]. Other structural features are in general accord with those expected for high-spin iron(III) porphyrinates.
FARMERS’ PERCEPTION OF CLIMATE CHANGE COMPARED WITH OBJECTIVE DATA: EVIDENCE FROM THE CENTRAL REGION OF GHANA
Authors: DADZIE SAMUEL KWESI NDZEBAH
Published: May 2020

Many studies of climate change adaptation have relied on farmers’ perceptions of climate change to explain why farmers are adopting new farming methods, and to advise adaptation policy framework that justifies Climate Smart Agriculture (CSA) especially in Africa. These studies have rarely verified whether farmers’ perceptions are consistent with observed changes in meteorological conditions to establish sufficient premise. This study compares farmers’ perceptions of changes in precipitation and temperature in a rainfed agriculture region of Ghana against objective measurements made in nearby weather stations in the region. The study finds that farmers correctly perceived the increase in temperature over time but incorrectly perceived a reduction in precipitation, while objective data showed high fluctuations with no clear trend. It is possible that farmers mistakenly assumed reduction in soil moisture meant to support crop growth requirements was caused by less rainfall when in fact it was caused by higher temperature.
Econometric Models of Network Formation
Authors: de Paula Áureo
Published: May 2020

This article provides a selective review of the recent literature on econometric models of network formation. I start with a brief exposition on basic concepts and tools for the statistical description of networks; then I offer a review of dyadic models, focusing on statistical models on pairs of nodes, and I describe several developments of interest to the econometrics literature. I also present a discussion of nondyadic models in which link formation might be influenced by the presence or absence of additional links, which themselves are subject to similar influences. This argument is related to the statistical literature on conditionally specified models and the econometrics of game theoretical models. I close with a (nonexhaustive) discussion of potential areas for further development.
Retinal Ganglion Cell Axon Wiring Establishing the Binocular Circuit
Authors: Mason Carol , Slavi Nefeli
Published: May 2020

Binocular vision depends on retinal ganglion cell (RGC) axon projection either to the same side or to the opposite side of the brain. In this article, we review the molecular mechanisms for decussation of RGC axons, with a focus on axon guidance signaling at the optic chiasm and ipsi- and contralateral axon organization in the optic tract prior to and during targeting. The spatial and temporal features of RGC neurogenesis that give rise to ipsilateral and contralateral identity are described. The albino visual system is highlighted as an apt comparative model for understanding RGC decussation, as albinos have a reduced ipsilateral projection and altered RGC neurogenesis associated with perturbed melanogenesis in the retinal pigment epithelium. Understanding the steps for RGC specification into ipsi- and contralateral subtypes will facilitate differentiation of stem cells into RGCs with proper navigational abilities for effective axon regeneration and correct targeting of higher-order visual centers.
Lower oxygen consumption and Complex I activity in mitochondria isolated from skeletal muscle of fetal sheep with intrauterine growth restriction
Authors: Pendleton Alexander L. , Antolic Andrew T. , Kelly Amy C. , Davis Melissa A. , Camacho Leticia E. , Doubleday Kevin , Anderson Miranda J. , Langlais Paul R. , Lynch Ronald M. , Limesand Sean W.
Published: May 2020

Fetal sheep with placental insufficiency-induced intrauterine growth restriction (IUGR) have lower hindlimb oxygen consumption rates (OCRs), indicating depressed mitochondrial oxidative phosphorylation capacity in their skeletal muscle. We hypothesized that OCRs are lower in skeletal muscle mitochondria from IUGR fetuses, due to reduced electron transport chain (ETC) activity and lower abundances of tricarboxylic acid (TCA) cycle enzymes. IUGR sheep fetuses ( n = 12) were created with mid-gestation maternal hyperthermia and compared with control fetuses ( n = 12). At 132 ± 1 days of gestation, biceps femoris muscles were collected, and the mitochondria were isolated. Mitochondria from IUGR muscle have 47% lower State 3 (Complex I-dependent) OCRs than controls, whereas State 4 (proton leak) OCRs were not different between groups. Furthermore, Complex I, but not Complex II or IV, enzymatic activity was lower in IUGR fetuses compared with controls. Proteomic analysis ( n = 6/group) identified 160 differentially expressed proteins between groups, with 107 upregulated and 53 downregulated mitochondria proteins in IUGR fetuses compared with controls. Although no differences were identified in ETC subunit protein abundances, abundances of key TCA cycle enzymes [isocitrate dehydrogenase (NAD+) 3 noncatalytic subunit β (IDH3B), succinate-CoA ligase ADP-forming subunit-β (SUCLA2), and oxoglutarate dehydrogenase (OGDH)] were lower in IUGR mitochondria. IUGR mitochondria had a greater abundance of a hypoxia-inducible protein, NADH dehydrogenase 1α subcomplex 4-like 2, which is known to incorporate into Complex I and lower Complex I-mediated NADH oxidation. Our findings show that mitochondria from IUGR skeletal muscle adapt to hypoxemia and hypoglycemia by lowering Complex I activity and TCA cycle enzyme concentrations, which together, act to lower OCR and NADH production/oxidation in IUGR skeletal muscle.
Replacing Detonation by Compressed Balloon Approaches in Finite Element Models
Authors: Legrand Pierre , Kerampran S. , Arrigoni M.
Published: May 2020

The evaluation of blast effects from malicious or accidental detonation of an explosive device is really challenging especially on large buildings. Indeed, the time and space scales of the explosion together with the chemical reactions and fluid mechanics make the numerical model really difficult to achieve acceptable structural design. Nevertheless, finite element methods and especially Arbitrary Lagrangian Eulerian (ALE) have been extensively used in the past few decades with some simplifications. Among them, the replacement of the explosive event by a compressed balloon of detonation products has been proven useful in numerous different situations. Unfortunately, the ALE algorithm does not achieve a proper energy balance through the numerical integration of the discrete scheme; this important drawback is not compensated by the use of the classical compressed balloon approach. The paper focuses on increasing the radius of the equivalent ideal gas balloon in order to achieve better energy balance and thus better results at later stages of the blast wave propagation.
Determination of an Optimal Oil Jet Nozzle Layout for Helical Gear Lubrication: Mathematical Modeling, Numerical Simulation, and Experimental Validation
Authors: Dai Yu , Jia Jifu , Ouyang Bin , Bian Jianeng
Published: May 2020

To provide a basic guidance for the selection of nozzle layout, a mathematical model of the impingement depth for helical gears under oil jet lubrication is established. Furthermore, computational fluid dynamics (CFD) methods are adopted to validate the effectiveness and accuracy of the derived impingement model. Firstly, the distribution characteristics of the oil volume fraction and oil-gas pressure in meshing area were obtained in flow field simulation. Meanwhile, the influence of spray angle, jet velocity, and gear ratio on lubrication effect was obtained. Then, the transient temperature field of the tooth surface was simulated by the method of thermal-fluid coupling analysis, and the lowest temperature distribution and the corresponding oil jet velocity were determined. Finally, experiments on the temperature characteristics measured by an infrared thermal imager of helical gears with different nozzle parameters were carried out in a gear test rig. The simulation results of transient temperature field are in good agreement with those obtained by experiments, and it indicates that the thermal-fluid coupling analysis method is correct and feasible to predict the temperature field of the helical gear pair under oil injection jet lubrication.