401 research outputs found
Social Media Use For Work: Does Work Experience Really Matter?
Social media are in the top of the agenda for many companies to date, however there seems to be very limited understanding of the usage of social media for work purposes. In this study, we investigate what values increase this usage, and whether that usage is related with employeesâ performance. Additionally, we explore the impact of employeesâ work experience on their social media behaviour. Our study is based on responses from 1799 employees in the insurance industry. Results confirmed that both utilitarian and hedonic values influence employees to use more social media for their work. In addition, this study confirms that there is an important relation between the use of social media and work performance. Last but not least, employeesâ work experience is found to be a significant moderator of the relationship between social media use for work and work performance
Wind and Tide-Induced Hydrodynamics and Sedimentation of Two Tidal Inlets in Western Greece
To quantify the detailed mechanisms that cause sedimentation at the tidal inlets in the Messolonghi-Aetoliko lagoonal system, the MIKE 21 FM (HD & ST) numerical simulation models were applied. The study focuses on the hydrodynamic circulation in the vicinity of the tidal inlets and the associated wind and tide-induced currents, as well as sediment transport, bed level evolution and total sediment load accumulation, with emphasis on the vicinity of two tidal inlets, where the problem is more acute. Based on the numerical predictions, which have been qualitatively corroborated via satellite images from Google Earth, it is shown that under the prevailing winds and tidal action, sandbars are formed in front or behind the tidal inlets depending on the wind direction, resulting in a gradual decrease of the mean water level at the mouths. Under the combined action of the tide and the wind the characteristic horizontal structure of the flow includes cyclonic and anti-cyclonic eddies that form at the near tip area of the jetties, which are associated with sediment transport mechanisms
Development of wind turbines to operate in modified axial flows which contain swirl velocities and non-uniform distributions
In pan A of this thesis, a procedure based on lifting line theory for the design of wind turbines operating in non-uniform, non-axial but axisymmetric flows is presented. This procedure was used for the design of conventional turbines which were compared with turbine designs produced by momentum theory. The overall trends of both theories were found to be similar, although the lifting line procedure was found to produce a more conservative estimate of the turbine performance. The above mentioned design procedure was also used for the turbine blade design of the wind power systems presented in parts B and C of the thesis.
Part B of the thesis deals with the development of the delta wing-turbine system: The system was scaled-up using the results of a previously developed design model, and its dimensions were compared with those of equivalent conventional turbines. It was found that the system compares well with conventional turbines up to rated power values equal to 100 kW. Its advantages were found to be the lower turbine diameter required for a given power output and the opportunity it provides for direct connection of the turbines to generators. The cost of this advantage is the relatively large delta wing required.
A system prototype with power output in the order of 1 kW was designed for testing. The prototype turbine blades were designed taking into account Reynolds number effects. In order to overcome the detrimental Re effects, use of a low Re aerofoil (GOE 795), reduction of the turbine number of blades to 10, increase of the blade chord, linear blade chord distribution and variable optimum angle of attack were found to be necessary, leading to a reduction of the turbine power coefficient drop to 4.7% below that of the original high Re design.
The prototype off design performance was predicted and it was found that increase of the blade chord at the hub region (for strength) and linearisation of the blade optimum twist angle (for ease of manufacture) did not affect the turbine performance significantly.
The generator to be used with the prototype turbine was bench-tested. Its model parameters and power losses were identified. For matching the generator with the turbine, an appropriate load for the generator was found. The prototype long-term performance was also estimated using the turbine performance characteristics, the generator test results and the Weibull distribution of wind occurrence probability. It was found that the generator is not ideally suited for the prototype turbine and that a generator of larger ratings would be more suitable.
Finally, the effects of yaw on the delta wing vortices were investigated experimentally. This was done in order to determine the feasibility of using the delta wing yaw to regulate the system power output. It was found that the above mentioned regulation technique can be used, provided that undue blade vibrations due to turbine-vortex misalignment and vortex bursting will not occur.
In part C, a procedure for the design of the counter-rotating turbine blades was developed. The above mentioned lifting line procedure as well as the existing knowledge of wind turbine wakes and counter-rotating rotor aerodynamics were used for the design of the counter-rotating turbine blades and the semi-empirical modelling of the two rotors' interaction.
The optimum axial distance between the two rotors was found to be equal to 1.4 times the rotors' radius. It was demonstrated that proper design of the turbine blades and appropriate axial positioning of the two rotors could increase the turbine performance by 27.4% above that of the original counter-rotating turbine design, called Trimble Mill.
It was also found that a considerable increase of the generator effective rotational speed (equal to 58%) can be achieved by the counter-rotating turbine, compared to that of a conventional turbine with the same number of blades, while the two turbines' power output was found to be at the same levels
Evaluation of the patients with syncope during the first month after coronary artery bypass graft
Background: Syncope is a well-known risk factor for adverse cardiovascular event in patients with coronary artery disease, especially those with previous myocardial infarction (MI) or left ventricular dysfunction. The aim of this study was to assess electrophysiologic findings and results of head-up tilt test (HUTT) in patients with syncope and without orthostatic changes in blood pressure during the first month after coronary artery bypass graft (CABG). Materials and Methods: A total of 20 patients with syncope during the first month after CABG were prospectively enrolled in this study from June 2002 to April 2006. Electrophysiologic study (EPS) was performed in all of them. HUTT was performed in all of the patients regardless of the result of EPS. Results: The mean age of patients was 60.311 years. Twelve patients were males. EPS was negative in 18 patients. HUTT was positive in 10 patients. Six patients had old MI. Ischemic insult occurred in one patient after CABG. Left bundle branch was present in two patients. There was a significant relationship between the duration of bed rest after CABG and positive HUTT (P value = 0.021). All of the patients except one did not experience syncope during the follow-up period. Conclusion: In patients with syncope during the first month post CABG, in whom an arrhythmic cause is suspected, the other cause of syncope like orthostatic intolerance should be considered. Being bedridden for an extended period of time post CABG can be a predisposing factor
Lâadaptation du virus de la clavelĂ©e sur les cellules rĂ©nales du mouton
Lang R., Leftheriotis E. Lâadaptation du virus de la clavelĂ©e sur les cellules rĂ©nales du mouton. In: Bulletin de l'AcadĂ©mie VĂ©tĂ©rinaire de France tome 114 n°8, 1961. pp. 337-343
Surveillance tensionnelle par automesure des patients cancéreux traités par anti-angiogénique (Comparaison de deux méthodes d'automesure et de leur impact sur la qualité de vie)
Les traitements anti-angiogĂ©niques (AAGG) occupent une place importante dans la prise en charge thĂ©rapeutique de nombreux cancers. De par leur action systĂ©mique, ils sont souvent responsables d'hypertension artĂ©rielle (HTA), ce qui implique une surveillance tensionnelle rĂ©guliĂšre pour maintenir une balance bĂ©nĂ©fice-risque favorable. A ce jour, l'apport de l'automesure tensionnelle et de la tĂ©lĂ©surveillance tensionnelle n'a pas Ă©tĂ© Ă©valuĂ© dans cette indication. Huit patients recrutĂ©s au CHU d'Angers et Ă l'ICO Paul Papin et traitĂ©s par un AAGG (Sunitinib - Sutent ou Bevacizumab - Avastin) ont bĂ©nĂ©ficiĂ© d'une surveillance tensionnelle selon 2 protocoles d'automesure diffĂ©rents, l'un suivant les recommandations de la HAS et l'autre celles du NCI-CTCAE, durant 2 cycles de traitement. Sept patients, recrutĂ©s dans les mĂȘmes conditions mais ne bĂ©nĂ©ficiant pas d'un traitement AAGG ont Ă©tĂ© suivi selon le mĂȘme protocole. L'impact psychologique du suivi par automesure couplĂ©e ou non Ă une tĂ©lĂ©surveillance a Ă©galement Ă©tĂ© Ă©valuĂ©e par une enquĂȘte. Les rĂ©sultats montrent un impact significatif du protocole d'automesure pour la dĂ©tection des Ă©pisodes d'HTA, malgrĂ© une contrainte plus importante liĂ©e Ă la rĂ©pĂ©tition des mesures (protocole HAS). L'utilisation d'un systĂšme de tĂ©lĂ©surveillance de l'automesure s'accompagne d'une amĂ©lioration de la qualitĂ© du recueil des donnĂ©es, facilite la dĂ©tection d'une HTA, permet une rĂ©duction des dĂ©lais d'interventions et augmente le sentiment de sĂ©curitĂ© du patient pour son suivi. Ces rĂ©sultats prĂ©liminaires encouragent le recourt Ă des systĂšmes de tĂ©lĂ©surveillance pour la prise en charge des patients traitĂ©s par AAGG.Anti-angiogenic treatments ( AAGG ) occupy an important place in management of many cancers. Arterial hypertension is a commonly reported side-effect. To date, the contribution of remote blood pressure monitoring was not evaluated. Eight patients recruited at the CHU of Angers and ICO Paul Papin and treated by AAGG ( Sunitinib - Sutent or Bevacizumab - Avastin ) benefited from monitoring blood pressure self-measurement (by HAS and NCI-CTCAE recommendations) during two cycles of treatment. Seven patients were recruited in the same conditions but does not benefit from AAGG treatment were followed too. The psychological impact of monitoring was evaluated by an inquiry .The results show a significant impact of self-measurement protocol for the detection of hypertension. A remote monitoring system is accompanied by an improvement quality of data, facilitates the detection of hypertension, reduces the intervention time and increases the sense of security. These preliminary results encourage the uses of remote monitoring systems for the management of patients treated with AAGG.ANGERS-BU MĂ©decine-Pharmacie (490072105) / SudocSudocFranceF
External Validation of the âWalking Estimated Limitation Calculated by Historyâ (WELCH) Questionnaire in Patients with Claudication
ObjectiveTo externally validate the recently proposed âWalking Estimated Limitation Calculated by Historyâ (WELCH) questionnaire.MethodsA prospective study was performed on 450 new patients referred to our laboratory for treadmill testing (constant load 3.2 km/h and 10% slope for 15 minutes and then incremental increases). Results are presented as mean ± SD or median [25thâ75th percentiles] or number (percentage). An ankle brachial index <0.90 defined the presence of peripheral artery disease (PAD). Typical âvascular-type claudicationâ is a lower-limb pain or discomfort that is absent at rest, appears at exercise, forces stopping, and disappears within 10 minutes of exercise stopping. The Spearman r coefficient of correlation between maximal walking time (MWT) on treadmill and WELCH scores was calculated for patients with (PAD+) or without (PADâ) PAD, and reporting typical vascular-type claudication (VTC+) or not (VTCâ).ResultsThe WELCH score was obtained in all included patients. The number (%) of patients with a WELCH score <25 was 37 (54%), 198 (65%), 14 (44%), and 18 (38%), and the Spearman correlation coefficient between WELCH score and treadmill MWT was 0.588, 0.609, 0.581, and 0.591 in the VTCâ/PAD+, VTC+/PAD+, VTCâ/PADâ, and VTC+/PADâ groups respectively (all p < .001). In PAD+/VTC+ patients, the WELCH positive predictive value for the inability to walk for 5 minutes on the treadmill was 79%.ConclusionThe WELCH score correlates moderately with treadmill-walking capacity in patients with or without PAD, and with or without typical VTC. It appears to be a simple to complete and easily scored instrument to help clinicians standardise the subjective estimation of walking capacity in their patients
BIPV-Powered Smart Windows Utilizing Photovoltaic and Electrochromic Devices
A BIPV-powered smart window comprising a building-integrated photovoltaic (BIPV) panel and an all-solid-state electrochromic (EC) stack is proposed. In the proposed device, the output voltage of the BIPV panel varies in accordance with the intensity of the incident light and is modulated in such a way as to generate the EC stack voltage required to maintain the indoor illuminance within a specified range. Two different EC stacks are fabricated and characterized, namely one stack comprising ITO/WO3/Ta2O5/ITO and one stack comprising ITO/WO3/lithium-polymer electrolyte/ITO. It is shown that of the two stacks, the ITO/WO3/lithium-polymer electrolyte/ITO stack has a larger absorptance (i.e., approximately 99% at a driving voltage of 3.5 V). The experimental results show that the smart window incorporating an ITO/WO3/lithium-polymer electrolyte/ITO stack with an electrolyte thickness of 1.0 ÎŒm provides an indoor illuminance range of 750â1,500 Lux under typical summertime conditions in Taiwan
Sensibilité des Porcs Miniatures au Virus de la Peste Porcine Classique
Favre H., Leftheriotis E., Terré Jean. Sensibilité des porcs miniatures au virus de la peste porcine classique. In: Bulletin de l'Académie Vétérinaire de France tome 119 n°8, 1966. pp. 9-272
- âŠ