LLukas22/scidocs huggingface dataset:
Design and control of biologically inspired wheel-less snake-like robot

This paper describes our research project on snake-like locomotion of robotic platforms and the results of the experiments conducted with a wheel-less snake-like robot prototype. Biological inspiration has been at the hardcore of the mechanical design and the control method applied to the robot. With closed-loop control applied to the present wheel-less prototype, it has succeeded in progressing through lateral undulation, the most common limbless locomotion type observed in natural snakes. Main results consist of the robustness of the locomotion with respect to the variations in initial conditions and external perturbations.
Are changes in mortality from stroke caused by changes in stroke event rates or case fatality? Results from the WHO MONICA Project.

BACKGROUND AND PURPOSE
Mortality from stroke has been declining over recent decades in most countries, except in Eastern Europe. In this analysis, based on the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) Project, we explored to what extent these trends are due to changes in stroke event rate and to changes in case fatality.


METHODS
The WHO MONICA Project collected standardized data from 14 populations in 9 countries. All acute strokes occurring in men and women 35 to 64 years of age were included. Registration was carried out between 1982 and 1995, resulting in time spans from 7 to 13 years. Trends in event rates and case fatality were calculated as average annual percentage change.


RESULTS
Up to 6-fold differences were observed in stroke mortality. Mortality declined in 8 of 14 populations in men and in 10 of 14 populations in women. An increase in mortality was observed in Eastern Europe. In the populations with a declining trend, about two thirds of the change could be attributed to a decline in case fatality. In populations with increasing mortality, the rise was explained by an increase in case fatality.


CONCLUSIONS
In most populations, changes in stroke mortality, whether declining or increasing, were principally attributable to changes in case fatality rather than changes in event rates. Whether this was due to changes in the management of stroke or changes in disease severity cannot be established on the basis of these results.
Stochastic analysis and control of real-time systems with random time delays

The paper discusses modeling and analysis of real-time systems subject to random time delays in the communication network. A new method for analysis of existing schemes is presented. The method is used to evaluate diierent suggested schemes from the literature. A new scheme for handling the random time delays is then developed and successfully compared with previous schemes. The new scheme is based on stochastic control theory and a separation property is shown to hold for the optimal controller. 1. INTRODUCTION Many real-time systems are implemented as distributed control systems, where the control loops are closed over a communication network. There will inevitably be time delays in the communication net. As long as the sampling periods are long compared with these delays there is no need to consider the innuence of the delays. As the demand on the control system increases it will be more and more important to take the delays into account in the analysis and the design of the control system. While inaccuracies, disturbances, etc, have been extensively studied in the control literature the timing problems in real-time systems have just recently attracted attention, and in the communication literature the feedback control aspect has not been treated extensively. This is thus an area where much can be gained by combining ideas from the two elds of control and real-time systems. Several problem formulations have been suggested by previous authors. A general setup would involve a dis
Understanding and measuring student engagement in school: the results of an international study from 12 countries.

The objective of the present study was to develop a scale that is appropriate for use internationally to measure affective, behavioral, and cognitive dimensions of student engagement. Psychometric properties of this scale were examined with data of 3,420 students (7th, 8th, and 9th grade) from 12 countries (Austria, Canada, China, Cyprus, Estonia, Greece, Malta, Portugal, Romania, South Korea, the United Kingdom, and the United States). The intraclass correlation of the full-scale scores of student engagement between countries revealed that it was appropriate to aggregate the data from the 12 countries for further analyses. Coefficient alphas revealed good internal consistency. Test-retest reliability coefficients were also acceptable. Confirmatory factor analyses indicated that the data fit well to a second-order model with affective, behavioral, and cognitive engagement as the first-order factors and student engagement as the second-order factor. The results support the use of this scale to measure student engagement as a metaconstruct. Furthermore, the significant correlations of the scale with instructional practices, teacher support, peer support, parent support, emotions, academic performance, and school conduct indicated good concurrent validity of the scale. Considerations and implications regarding the international use of this student engagement in school measure are discussed.
Fampridine treatment and walking distance in multiple sclerosis: A randomised controlled trial

OBJECTIVE
To explore the benefits of modified-release fampridine on walking distance in MS.


METHODS
This was a randomised double-blind, placebo-controlled crossover trial of fampridine in 25 MS patients. The primary outcome measure was the six minute walk test (6MWT). A p-value<10% led to rejection of the null hypothesis.


RESULTS
The pre-specified criterion for statistical significance was met, with a 17m improvement in 6MWT in the treatment arm. In addition, baseline S2 accommodation, a nerve excitability parameter that reflects slow K+ channel activity, modified the effect of fampridine. For patients who had abnormally high S2 accommodation values, there was a 28m improvement in the 6MWT (p=0.04). In contrast, for patients with low S2 values, a 0m improvement was noted (p=1.0).


CONCLUSION
The study provides evidence that fampridine may improve walking distance. Nerve excitability assessment may be useful in selecting those patients who are most likely to gain benefit from fampridine.


SIGNIFICANCE
Fampridine may improve walking distance in MS. Nerve excitability assessment may assist in identifying those patients most likely to respond to fampridine.
Common skin conditions during pregnancy.

Common skin conditions during pregnancy generally can be separated into three categories: hormone-related, preexisting, and pregnancy-specific. Normal hormone changes during pregnancy may cause benign skin conditions including striae gravidarum (stretch marks); hyperpigmentation (e.g., melasma); and hair, nail, and vascular changes. Preexisting skin conditions (e.g., atopic dermatitis, psoriasis, fungal infections, cutaneous tumors) may change during pregnancy. Pregnancy-specific skin conditions include pruritic urticarial papules and plaques of pregnancy, prurigo of pregnancy, intrahepatic cholestasis of pregnancy, pemphigoid gestationis, impetigo herpetiformis, and pruritic folliculitis of pregnancy. Pruritic urticarial papules and plaques of pregnancy are the most common of these disorders. Most skin conditions resolve postpartum and only require symptomatic treatment. However, there are specific treatments for some conditions (e.g., melasma, intrahepatic cholestasis of pregnancy, impetigo herpetiformis, pruritic folliculitis of pregnancy). Antepartum surveillance is recommended for patients with intrahepatic cholestasis of pregnancy, impetigo herpetiformis, and pemphigoid gestationis.
Incidence of erectile dysfunction in 800 hypertensive patients: a multicenter Egyptian national study.

OBJECTIVES
To evaluate the incidence of erectile dysfunction (ED), its severity, and other sexual function domains in 800 Egyptian patients with hypertension.


METHODS
All patients completed a detailed questionnaire addressing their general medical history, with special emphasis on hypertension (ie, duration of hypertension, type of antihypertensive treatment, compliance, and presence of any complications). Sexual function was evaluated with the International Index of Erectile Function.


RESULTS
The mean +/- SD patient age was 59.2 +/- 2.3 years (range 28 to 75). Of the 800 patients, 739 (92.3%) had regular sexual activity (one to two times per week) and 346 (43.2%) had ED. Of the 346 men, 40 (5%), 96 (12%), and 210 (26.2%) had mild, moderate, and severe ED, respectively. A highly statistically significant correlation was found between the duration of hypertension and the duration of weak erections. Only 41 patients (12%) with ED reported receiving erectogenic drug therapy.


CONCLUSIONS
Our results have shown a greater prevalence of ED in the Egyptian hypertensive population. The presence of another risk factor in addition to elevated blood pressure can increase the incidence of ED further.
Microvascular Density in Glaucomatous Eyes With Hemifield Visual Field Defects: An Optical Coherence Tomography Angiography Study.

PURPOSE
To investigate microcirculation of peripapillary retina and optic disc in eyes with primary open-angle glaucoma (POAG) and hemifield visual field (VF) defects.


DESIGN
Prospective observational case series with normal comparison group.


METHODS
Sixty eyes with POAG (41 with superior and 19 with inferior hemifield VF defects) and 21 normal eyes were included in this study. Optical coherence tomography (OCT) angiography was used to acquire 3 × 3-mm optic disc cubes, and circumpapillary retinal nerve fiber layer thickness was also measured using OCT. Vessel densities in the peripapillary superficial retina and whole-signal-mode optic disc were individually analyzed based on the sectorial division.


RESULTS
The peripapillary vessel densities were significantly reduced at the corresponding location of the VF defects in both non-highly myopic (P < .001, P = .006) and highly myopic glaucomatous eyes (P < .001, P = .005) compared with the normal eyes. Vessel densities of the optic discs were significantly reduced at locations corresponding to the VF defects in eyes without high myopia but with inferior hemifield VF defects (P = .006), but not in the other eyes. The vessel densities in the peripapillary retina were significantly associated with visual field total deviation values at their corresponding sides. The choroidal microvascular reduction in the peripapillary area extended to the α-peripapillary atrophy (PPA) as well as β-PPA zones.


CONCLUSIONS
Microvascular reduction was associated with VF defects in a region-specific manner: significantly and partially in the peripapillary retina and optic disc, respectively.
Content Delivery Networks: State of the Art, Insights, and Imperatives

Over the last decades, users have witnessed the growth and maturity of the Internet which has caused enormous growth in network traffic, driven by the rapid acceptance of broadband access, the increases in systems complexity, and the content richness. The over-evolving nature of the Internet brings new challenges in managing and delivering content to users, since for example, popular Web services often suffer congestion and bottlenecks due to the large demands posed on their services. Such a sudden spike in Web content requests (e.g. the one occurred during the 9/11 incident in USA) is often termed as flash crowds [14] or SlashDot [11] effects. It may cause heavy workload on particular Web server(s), and as a result a “hotspot” [14] can be generated. Coping with such unexpected demand causes significant strain on a Web server and eventually the Web servers are totally overwhelmed with the sudden increase in traffic, and the Web site holding the content becomes temporarily unavailable. A Content Delivery Network (CDN) [47, 51, 54, 61, 63] is a collaborative collection of network elements spanning the Internet, where content is replicated over several mirrored Web servers in order to perform transparent and effective delivery of content to the end users. Collaboration among distributed CDN components can occur over nodes in both homogeneous and heterogeneous environments. CDNs have evolved to overcome the inherent limitations of the Internet in terms of user perceived Quality of Service (QoS) when accessing Web content. They provide services that improve network performance by maximizing bandwidth, improving
Genetic association of the transcription of neuroplasticity-related genes and variation in stress-coping style

INTRODUCTION
Stress coping has been defined as the cognitive and behavioral efforts made to conquer, endure, or decrease external and internal demands and the conflicts between them. It has two main elements: the control or modification of the person-environment relationship causing the stress (i.e., problem-focused coping) and/or regulation of stressful feelings (i.e., emotion-focused coping). Research suggests that the expressions of brain-derived neurotrophic factor (BDNF) and neurotrophic tyrosine kinase receptor type 2 (NTRK2) play important roles in brain adaptation to investigate stress. To clarify the genetic basis of stress coping, we investigated the association of stress-coping strategies and social adaptation with single-nucleotide polymorphisms (SNPs) involved in neural plasticity, anxiety, and depression.


METHODS
In 252 healthy controls (94 women; 158 men), we measured and estimated the stress-coping style using the Lazarus-type stress-coping inventory, ego aptitude scale (EAS), and social adaptation self-evaluation scale (SASS). We investigated one SNP of BDNF (rs6265, Val/Met) and five SNPs of NTRK2 (rs11140800, rs1187286, rs1867283, rs1147198, and rs10868235).


RESULTS
We observed significant associations between BDNF and emotion-focused strategies, seeking social support, self-control, and distancing. We also found significant associations between NTRK2 and cognitive strategies, problem-solving, confrontive- coping, seeking social support, distancing and positive reappraisal. Significant associations were also found between BDNF and critical attitudes and between NTRK2 and all seven ego-related factors on the EAS. In the SASS, the minor allele rs1867283 of NTRK2 had a significantly higher score than the heterozygote.


CONCLUSIONS
These findings may provide insights into the partial effects of genetic mutations in BDNF and NTRK2 on stress tolerance and personality.
Mechanics of high speed cutting with curvilinear edge tools

High speed cutting is advantageous due to the reduced forces and power, increased energy savings, and overall improved productivity for discrete-part metal manufacturing. However, tool edge geometry and combined cutting conditions highly affects the performance of high speed cutting. In this study, mechanics of cutting with curvilinear (round and oval-like) edge preparation tools in the presence of dead metal zone has been presented to investigate the effects of edge geometry and cutting conditions on the friction and resultant tool temperatures. An analytical slip-line field model is utilized to study the cutting mechanics and friction at the tool-chip and tool–workpiece interfaces in the presence of the dead metal zone in machining with negative rake curvilinear PCBN tools. Inserts with six different edge designs, including a chamfered edge, are tested with a set of orthogonal cutting experiments on AISI 4340 steel. Friction conditions in each different edge design are identified by utilizing the forces and chip geometries measured. Finite-element simulations are conducted using the friction conditions identified and process predictions are compared with experiments. Analyses of temperature, strain, and stress fields are utilized in understanding the mechanics of machining with curvilinear tools. r 2007 Elsevier Ltd. All rights reserved.
Lack of pharmacokinetic interaction between ropinirole and theophylline in patients with Parkinson's disease

Objective: Ropinirole and theophylline have the potential to interact, because they use the same hepatic cytochrome P450 (CYP1A2) as their major metabolic pathway. The present study investigated the effect of steady-state oral theophylline on the pharmacokinetics of ropinirole at steady state and the effect of steady-state ropinirole on the pharmacokinetics of a single intravenous (i.v.) dose of theophylline, both in patients with idiopathic Parkinson's disease (PD). Methods: Pharmacokinetic parameters (AUC and Cmax) for i.v. theophylline were compared before and after a 4-week period of oral treatment with ropinirole (2 mg t.i.d.) in 12 patients with PD. Patients were then maintained at this dose of ropinirole, and oral theophylline was co-administered at doses of up to 300 mg b.i.d. The parameters AUC, Cmax and tmax for ropinirole were compared before, during and after oral theophylline co-treatment. Results: Co-administration of ropinirole did not significantly change the pharmacokinetics of i.v. theophylline (mean AUC with and without ropinirole: 68.6 μg · h−1 · ml−1 and 70.0 μ· h−1 · ml−1, respectively; mean Cmax with and without ropinirole: 11.07 μ g · ml−1 and 11.83 μg · ml−1, respectively). Similarly, there were no significant changes in ropinirole pharmacokinetics when the drug was co-administered with oral theophylline (mean AUC for ropinirole with and without theophylline: 21.91 ng · h−1 · ml−1 and 22.09 ng · h−1 · ml−1, respectively; mean Cmax for ropinirole with and without theophylline: 5.65 ng · ml−1 and 5.54 ng · ml−1, respectively; median tmax for ropinirole with and without theophylline: 2.0 h and 1.5 h, respectively). Conclusion: These results suggest a lack of significant pharmacokinetic interaction between the two drugs at current therapeutic doses.
Health-related quality of life in total hip and total knee arthroplasty. A qualitative and systematic review of the literature.

BACKGROUND
Total hip and total knee arthroplasties are well accepted as reliable and suitable surgical procedures to return patients to function. Health-related quality-of-life instruments have been used to document outcomes in order to optimize the allocation of resources. The objective of this study was to review the literature regarding the outcomes of total hip and knee arthroplasties as evaluated by health-related quality-of-life instruments.


METHODS
The Medline and EMBASE medical literature databases were searched, from January 1980 to June 2003, to identify relevant studies. Studies were eligible for review if they met the following criteria: (1). the language was English or French, (2). at least one well-validated and self-reported health-related quality of life instrument was used, and (3). a prospective cohort study design was used.


RESULTS
Of the seventy-four studies selected for the review, thirty-two investigated both total hip and total knee arthroplasties, twenty-six focused on total hip arthroplasty, and sixteen focused on total knee arthroplasty exclusively. The most common diagnosis was osteoarthritis. The duration of follow-up ranged from seven days to seven years, with the majority of studies describing results at six to twelve months. The Short Form-36 and the Western Ontario and McMaster University Osteoarthritis Index, the most frequently used instruments, were employed in forty and twenty-eight studies, respectively. Seventeen studies used a utility index. Overall, total hip and total knee arthroplasties were found to be quite effective in terms of improvement in health-related quality-of-life dimensions, with the occasional exception of the social dimension. Age was not found to be an obstacle to effective surgery, and men seemed to benefit more from the intervention than did women. When improvement was found to be modest, the role of comorbidities was highlighted. Total hip arthroplasty appears to return patients to function to a greater extent than do knee procedures, and primary surgery offers greater improvement than does revision. Patients who had poorer preoperative health-related quality of life were more likely to experience greater improvement.


CONCLUSIONS
Health-related quality-of-life data are valuable, can provide relevant health-status information to health professionals, and should be used as a rationale for the implementation of the most adequate standard of care. Additional knowledge and scientific dissemination of surgery outcomes should help to ensure better management of patients undergoing total hip or total knee arthroplasty and to optimize the use of these procedures.
Mild traumatic brain injury

Mild traumatic brain injury P. E. Vos, Y. Alekseenko, L. Battistin, E. Ehler, F. Gerstenbrand, D. F. Muresanu, A. Potapov, C. A. Stepan, P. Traubner, L. Vecsei and K. von Wild Radboud University Nijmegen Medical Centre, The Netherlands; Vitebsk Medical University, Vitebsk, Belarus; Clinica Neurologica I, Padova, Italy; Neurologicka Klinika, Pradubice, Czech Republic; Ludwig Boltzmann Institute for Restorative Neurology and Neuromodulation, Vienna, Austria; University CFR Hospital, University of Medicine and Pharmacy Iuliu Hatieganu Cluj-Napoca, Romania; Institute of Neurosurgery, Russian Academy of Medical Sciences, Moscow, Russia; Neurological Hospital Rosenh ü gel, Vienna, Austria; Comenius University School of Medicine, Bratislava, Slovak Republic; Szent-Györgyi University Hospital, Szeged, Hungary; and Medical Faculty Westphalien University Münster and International Neuroscience Institute INI, Hannover, Germany
ON AN SO(5) UNIFICATION ATTEMPT FOR THE CUPRATES

We provide a brief critique on the relevance of the quantum critical phenomenon notion for our understanding of the anomalous insulating and conducting states of cuprates. In particular, we focus on Zhang's SO(5) unification idea and the interpretation of the 41 meV neutron resonance as an underlying pseudo goldstone mode.