scholarly journals Biomechanická analýza štartových skokov v plávaní

2014 ◽  
Vol 8 (1) ◽  
pp. 109-125
Author(s):  
Ivan Matúš
Keyword(s):  
Reaction Time ◽  
Statistical Significance ◽  
Maximum Force ◽  
Vertical Force ◽  
Horizontal Force

Presented research comes up with results representing a role of speed-force and timing parameters in four start types at the track of 7.5 m and 10 m distance. Eighteen performance male swimmers (age 23.4±2.1), specialists in sprint event, participated in this study. We noticed the highest measured vertical force in swimming starts with rearward stretch (ZŠSN, AŠSN) in both track distances. For the horizontal force in the tracks of both distances we noticed the highest values of maximum force in grab starts (ZŠS, ZŠSN), but the average values were the highest in the track starts (AŠSN, AŠS). From the timing parameters on the starting block, the shortest reaction time was measured in swimming starts with rearward stretch (ZŠSN, AŠSN). The shortest movement and starting reaction time from the starting block was measured in the swimming start with rearward stretch (ZŠSN, AŠSN) in both track distances. The shortest time of a flight and gliding phase for the track of 7.5 m and 10 m distance we measured in the track start with rearward. Difference between the first and the second fastest time in the track of 7.5 m distance to 0,02 s, but the track of 10 m distance was doubled. On the basis of these results we recommend to swimmer sprinters to use mainly the track start with rearward. The statistical significance of differences in speed-force parameters pointed on the differences between the four types of swimming starts. In all types of the starts were shown close relations between the track time for 7.5 m and 10 m distance, horizontal force parameters and the time of the flight and gliding phase.

scholarly journals Birds repurpose the role of drag and lift to take off and land

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Diana D. Chin ◽  
David Lentink
Keyword(s):  
Flapping Wings ◽  
Vertical Force ◽  
Horizontal Force ◽  
Aerodynamic Forces ◽  
Braking Force ◽  
Drag And Lift ◽  
Lift And Drag ◽  
Wing Stroke

AbstractThe lift that animal wings generate to fly is typically considered a vertical force that supports weight, while drag is considered a horizontal force that opposes thrust. To determine how birds use lift and drag, here we report aerodynamic forces and kinematics of Pacific parrotlets (Forpus coelestis) during short, foraging flights. At takeoff they incline their wing stroke plane, which orients lift forward to accelerate and drag upward to support nearly half of their bodyweight. Upon landing, lift is oriented backward to contribute a quarter of the braking force, which reduces the aerodynamic power required to land. Wingbeat power requirements are dominated by downstrokes, while relatively inactive upstrokes cost almost no aerodynamic power. The parrotlets repurpose lift and drag during these flights with lift-to-drag ratios below two. Such low ratios are within range of proto-wings, showing how avian precursors may have relied on drag to take off with flapping wings.

scholarly journals The role of extensive recasts in error detection and correction by adult ESL students

2016 ◽  
Vol 6 (1) ◽  
pp. 19-41 ◽  
Author(s):  
Laura Hawkes ◽  
Hossein Nassaji
Keyword(s):  
Reaction Time ◽  
Error Detection ◽  
Statistical Significance ◽  
Communicative Interaction ◽  
Adult Esl ◽  
Error Detection And Correction ◽  
Original Definition ◽  
Written Test ◽  
Definition Of

Most of the laboratory studies on recasts have examined the role of intensive recasts provided repeatedly on the same target structure. This is different from the original definition of recasts as the reformulation of learner errors as they occur naturally and spontaneously in the course of communicative interaction. Using a within-group research design and a new testing methodology (video-based stimulated correction posttest), this laboratory study examined whether extensive and spontaneous recasts provided during small-group work were beneficial to adult L2 learners. Participants were 26 ESL learners, who were divided into seven small groups (3-5 students per group), and each group participated in an oral activity with a teacher. During the activity, the students received incidental and extensive recasts to half of their errors; the other half of their errors received no feedback. Students’ ability to detect and correct their errors in the three types of episodes was assessed using two types of tests: a stimulated correction test (a video-based computer test) and a written test. Students’ reaction time on the error detection portion of the stimulated correction task was also measured. The results showed that students were able to detect more errors in error+recast (error followed by the provision of a recast) episodes than in error-recast (error and no recast provided) episodes (though this difference did not reach statistical significance). They were also able to successfully and partially successfully correct more errors in error+recast episodes than in error-recast episodes, and this difference was statistically significant on the written test. The reaction time results also point towards a benefit from recasts, as students were able to complete the task (slightly) more quickly for error+recast episodes than for error-recast episodes.

Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man

1995 ◽  
Vol 133 (6) ◽  
pp. 723-728 ◽  
Author(s):  
Ettore C degli Uberti ◽  
Maria R Ambrosio ◽  
Marta Bondanelli ◽  
Giorgio Transforini ◽  
Alberto Valentini ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Subjects ◽  
Sympathetic Nerve Activity ◽  
Heart Rate Response ◽  
Statistical Significance ◽  
Inhibitory Effect ◽  
Amino Acid Residues ◽  
Nerve Activity ◽  
Receptor Stimulation

degli Uberti EC, Ambrosio MR, Bondanelli M, Trasforini G, Valentini A, Rossi R, Margutti A, Campo M. Effect of human galanin on the response of circulating catecholamines to hypoglycemia in man. Eur J Endocrinol 1995;133:723–8. ISSN 0804–4643 Human galanin (hGAL) is a neuropeptide with 30 amino acid residues that has been found in the peripheral and central nervous system, where it often co-exists with catecholamines. In order to clarify the possible role of hGAL in the regulation of sympathoadrenomedullary function, the effect of a 60 min infusion of hGAL (80 pmol·kg−1 · min−1) on plasma epinephrine and norepinephrine responses to insulin-induced hypoglycemia in nine healthy subjects was investigated. Human GAL administration significantly reduced both the release of basal norepinephrine and the response to insulin-induced hypoglycemia, whereas it attenuated the epinephrine response by 26%, with the hGAL-induced decrease in epinephrine release failing to achieve statistical significance. Human GAL significantly increased the heart rate in resting conditions and clearly exaggerated the heart rate response to insulin-induced hypoglycemia, whereas it had no effect on the blood pressure. We conclude that GAL receptor stimulation exerts an inhibitory effect on basal and insulin-induced hypoglycemia-stimulated release of norepinephrine. These findings provide further evidence that GAL may modulate sympathetic nerve activity in man but that it does not play an important role in the regulation of adrenal medullary function. Ettore C degli Uberti, Chair of Endocrinology, University of Ferrara, Via Savonarola 9, I-44100 Ferrara, Italy

Fore-Aft Forces in Tire-Wheel Assemblies Generated by Unbalances and the Influence of Balancing

1991 ◽  
Vol 19 (3) ◽  
pp. 142-162 ◽  
Author(s):  
D. S. Stutts ◽  
W. Soedel ◽  
S. K. Jha
Keyword(s):  
Mathematical Model ◽  
Elastic Foundation ◽  
Torsional Oscillation ◽  
Vertical Direction ◽  
Torsional Stiffness ◽  
Rolling Motion ◽  
Vertical Force ◽  
Horizontal Force ◽  
Wheel Rim ◽  
Open Question

Abstract When measuring bearing forces of the tire-wheel assembly during drum tests, it was found that beyond certain speeds, the horizontal force variations or so-called fore-aft forces were larger than the force variations in the vertical direction. The explanation of this phenomenon is still somewhat an open question. One of the hypothetical models argues in favor of torsional oscillations caused by a changing rolling radius. But it appears that there is a simpler answer. In this paper, a mathematical model of a tire consisting of a rigid tread ring connected to a freely rotating wheel or hub through an elastic foundation which has radial and torsional stiffness was developed. This model shows that an unbalanced mass on the tread ring will cause an oscillatory rolling motion of the tread ring on the drum which is superimposed on the nominal rolling. This will indeed result in larger fore-aft than vertical force variations beyond certain speeds, which are a function of run-out. The rolling motion is in a certain sense a torsional oscillation, but postulation of a changing rolling radius is not necessary for its creation. The model also shows the limitation on balancing the tire-wheel assembly at the wheel rim if the unbalance occurs at the tread band.

Chemical Availability of Bromide Dictates CsPbBr3 Nanocrystal Growth

2019 ◽  
Author(s):  
Je-Ruei Wen ◽  
Benjamin Roman ◽  
Freddy Rodriguez Ortiz ◽  
Noel Mireles Villegas ◽  
Nicholas Porcellino ◽  
...  
Keyword(s):  
Reaction Time ◽  
Growth Mechanism ◽  
Chemical Control ◽  
Critical Role ◽  
Phase Evolution ◽  
Detailed Understanding ◽  
Semiconductor Nanocrystal ◽  
Nanocrystal Growth ◽  
Chemical Availability

Lack of detailed understanding of the growth mechanism of CsPbBr3 nanocrystals has hindered sophisticated morphological and chemical control of this important emerging optoelectronic material. Here, we have elucidated the growth mechanism by slowing the reaction kinetics. When 1-bromohexane is used as an alternative halide source, bromide is slowly released into the reaction mixture, extending the reaction time from ~3 seconds to greater than 20 minutes. This enables us to monitor the phase evolution of products over the course of reaction, revealing that CsBr is the initial species formed, followed by Cs4PbBr6, and finally CsPbBr3. Further, formation of monodisperse CsBr nanocrystals is demonstrated in a bromide-deficient and lead-abundant solution. The CsBr can only be transformed into CsPbBr3 nanocubes if additional bromide is added. Our results indicate a fundamentally different growth mechanism for CsPbBr3 in comparison with more established semiconductor nanocrystal systems and reveal the critical role of the chemical availability of bromide for the growth reactions.<br>

Effects of High Intensity Statin Therapy in the Treatment of Diabetic Dyslipidemia in Patients with Coronary Artery Disease

2018 ◽  
Vol 24 (4) ◽  
pp. 427-441 ◽  
Author(s):  
Marija Vavlukis ◽  
Sasko Kedev
Keyword(s):  
Statin Therapy ◽  
High Intensity ◽  
Statistical Significance ◽  
Incident Diabetes ◽  
Moderate Intensity ◽  
Protective Effects ◽  
Pcsk9 Inhibitors ◽  
Diabetic Dyslipidemia ◽  
Patients With Diabetes

Background: Diabetic dyslipidemia has specifics that differ from dyslipidemia in patients without diabetes, which contributes to accelerated atherosclerosis equally as dysglycemia. The aim of this study was to deduce the interdependence of diabetic dyslipidemia and cardiovascular diseases (CVD), therapeutic strategies and the risk of diabetes development with statin therapy. Method: We conducted a literature review of English articles through PubMed, PubMed Central and Cochrane, on the role of diabetic dyslipidemia in atherosclerosis, the antilipemic treatment with statins, and the role of statin therapy in newly developed diabetes, by using key words: atherosclerosis, diabetes mellitus, diabetic dyslipidemia, CVD, statins, nicotinic acid, fibrates, PCSK9 inhibitors. Results: hyperglycemia and dyslipidemia cannot be treated separately in patients with diabetes. It seems that dyslipidemia plays one of the key roles in the development of atherosclerosis. High levels of TG, decreased levels of HDL-C and increased levels of small dense LDL- C particles in the systemic circulation are the most specific attributes of diabetic dyslipidemia, all of which originate from an inflated flux of free fatty acids occurring due to the preceding resistance to insulin, and exacerbated by elevated levels of inflammatory adipokines. Statins are a fundamental treatment for diabetic dyslipidemia, both for dyslipidemia and for CVD prevention. The use of statin treatment with high intensity is endorsed for all diabetes-and-CVD patients, while a moderate - intensity treatment can be applied to patients with diabetes, having additional risk factors for CVD. Statins alone are thought to possess a small, although of statistical significance, risk of incident diabetes, outweighed by their benefits. Conclusion: As important as hyperglycemia and glycoregulation are in CVD development in patients with diabetes, diabetic dyslipidemia plays an even more important role. Statins remain the cornerstone of antilipemic treatment in diabetic dyslipidemia, and their protective effects in CVD progression overcome the risk of statin- associated incident diabetes.

Do we Need Maintenance Chemotherapy in Advanced NSCLC in the Era of Immune and Targeted Therapy?

2019 ◽  
Vol 15 (1) ◽  
pp. 50-55
Author(s):  
Ahmed Nagy ◽  
Omar Abdel Rahman ◽  
Heba Abdullah ◽  
Ahmed Negida
Keyword(s):  
Lung Cancer ◽  
Maintenance Therapy ◽  
Small Cell Lung Cancer ◽  
Cell Lung Cancer ◽  
Statistical Significance ◽  
Small Cell ◽  
Maintenance Chemotherapy ◽  
Small Cell Lung ◽  
The Impact

Background: Although well established for the effective management of hematologic cancers, maintenance chemotherapy has only been recently incorportated as a treatment paradigm for advanced non–small-cell lung cancer. Maintenance chemotherapy aims to prolong a clinically favorable response state achieved after finishing induction therapy which is usually predefined in number before startng treatment. There are 2 modalities for maintenance therapy; continuation maintenance (involving a non-platinum component which was a part of the induction protocol or a targeted agent) and switch maintenance therapy (utilizing a new agent which was not a part of the induction regimen). Methods: The purpose of this article is to review the role of maintenance therapy in the treatment of advanced Non-Small Cell Lung Cancer (NSCLC) and provide a brief overview about induction chemotherapy in NSCLC to address the basis of maintenance therapy as a treatment option. We will also compare the impact of maintenance chemotherapy with the now evolving role of immunotherapy in NSCLC. Results: There have been 4 maintenance studies to date showing prolonged PFS and OS with statistical significance. However, Three out of the four studies (ECOG4599, JMEN, and PARAMOUNT) did not report tumor molecular analysis. As regard Immunotherapy, current data is in favour of strongly an increasing role for immunotherapy in NSCLC. Conclusion: Maintenance therapy in NSCLC continues to be an important therapeutic line to improve outcome in patients with metastatic and recurrent disease.

scholarly journals Chemotherapy alone versus definitive concurrent chemoradiotherapy for cT4b esophageal squamous cell carcinoma: a population-based study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chia-Chin Li ◽  
Chih-Yi Chen ◽  
Ying-Hsiang Chou ◽  
Chih-Jen Huang ◽  
Hsiu-Ying Ku ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Esophageal Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Concurrent Chemoradiotherapy ◽  
Statistical Significance ◽  
Treatment Options ◽  
Population Based ◽  
Primary Analysis

Abstract Background The role of radiotherapy for cT4bNanyM0 esophageal squamous cell carcinoma (ESqCC) is relatively unclear, with both chemotherapy (C/T) alone and definitive concurrent chemoradiotherapy (dCCRT) being treatment options in the current guidelines. We aimed to compare the survival of dCCRT versus C/T for these patients via a population-based approach. Methods Eligible cT4b ESqCC patients diagnosed between 2011 and 2017 were identified via the Taiwan Cancer Registry. We used propensity score (PS) weighting to balance the observable potential confounders between groups. The hazard ratio (HR) of death and incidence of esophageal cancer mortality (IECM) were compared between dCCRT and C/T. We also evaluated OS in subgroups of either low or standard radiotherapy doses. Results Our primary analysis consisted of 247 patients in whom covariates were well balanced after PS weighing. The HR for death when dCCRT was compared with C/T was 0.36 (95% confidence interval 0.24–0.53, P < 0.001). Similar results were found for IECM. Statistical significance was only observed in the standard RT dose but not in the low dose in subgroup analyses. Conclusions In this population-based nonrandomized study of cT4bNanyM0 ESqCC patients from Asia (Taiwan), we found that the use of radiotherapy with chemotherapy was associated with better overall survival than chemotherapy alone. Further studies (especially RCTs) are needed to confirm our findings.

Bacteriophages immunomodulate the response of monocytes

2021 ◽  
pp. 153537022199515
Author(s):  
Lídia Perea ◽  
Lorena Rodríguez-Rubio ◽  
Juan C Nieto ◽  
Carlos Zamora ◽  
Elisabet Cantó ◽  
...  
Keyword(s):  
Cytokine Production ◽  
Statistical Significance ◽  
Control Sample ◽  
Polymyxin B ◽  
Dependent Manner ◽  
Direct Role ◽  
Gram Positive Bacteria ◽  
Hla Dr ◽  
Tnf Α

Bacteriophages are present in fluids from cirrhosis patients. However, their effect on the immune response is unknown. In this work, we explore the role of phages in the phenotype, function, and cytokine production of monocytes. We stimulated healthy monocytes with five different butanol-purified phage suspensions infective for Gram-negative and Gram-positive bacteria. We studied the expression of the monocyte markers involved in lipopolysaccharide recognition (LPS; CD14), antigen presentation (HLA-DR) and co-stimulation (CD86), and the concentration of induced cytokines (TNF-α, IFN-α, and IL-10) by phages. To confirm the direct role of phages without the interference of contaminating soluble LPS in phage suspensions, polymyxin B was added to the cell cultures. Phagocytosis experiments were assessed by flow cytometry using labeled phage suspensions. We observed that butanol-purified phages reduced the surface levels of CD14 and CD86 in monocytes and increased the secreted levels of TNF-α and IL-10 compared with the control sample containing only butanol buffer. All phage suspensions showed downregulation of HLA-DR expression but only Staphylococcus aureus phage contaminated with Escherichia coli reached statistical significance. The addition of polymyxin B did not restore the monocytic response induced by phages, suggesting that the effect was not caused by the presence of LPS. Monocytes were able to phagocyte phages in a dose- and time-dependent manner. To conclude, the phagocytosis of butanol-purified phages altered the phenotype and cytokine production of monocytes suggesting they become tolerogenic.

scholarly journals Report of the Kew Committee for the fourteen months ending December 31, 1891

1892 ◽  
Vol 51 (308-314) ◽  
pp. 152-182
Keyword(s):  
Vertical Force ◽  
Horizontal Force ◽  
Increased Activity

The operations of The Kew Observatory, in the Old Deer Park, Richmond, Surrey, are controlled by the Kew Committee, which is constituted as follows: The magnetographs have worked satisfactorily all through since last report. The curves obtained, representing Declination, Horizontal Force, and Vertical Force, have shown a marked increased activity in terrestrial magnetic changes as compared with the preceding year, although no very large disturbances have been registered.

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