Search results for "gravity"
showing 10 items of 537 documents
Slope Failures and MTDs along a Cretaceous Escarpment in Western Sicily (Italy)
2018
In the last decades, many contributions have examined the Mass Transport Deposits (MTDs) in both modern and ancient examples for the comprehension of the sedimentary dynamics along the carbonate escarpments. Such sedimentary bodies have a great economic significance, since they are widely considered prone to the development of petroleum systems. In particular, MTDs from Cretaceous escarpments are well known from many regions of the world, since they are typically rich in rudists aragonite fragments determining high percentages of porosity. In these respect the deep knowledge on the facies architecture of these depositional systems is of broad interest as can offer examples for the predictio…
The factor content of regional bilateral trade: The role of technology and demand
2011
Abstract The Heckscher–Ohlin–Vanek (HOV) model in its strict form has been strongly rejected by the data. Relaxing some assumptions of the standard HOV model is key to find improvements in its performance. We apply the Davis and Weinstein (2001) methodology to analyse the validity of the HOV model using regions rather than countries. Surprisingly, our results using data for 17 Spanish regions are similar to theirs with international data for OECD countries. Accounting for technological differences improves the predictive capacity of the factor proportions model and including trade costs and geography reduces significantly the missing trade problem. However, relaxing the assumption of factor…
Is the ‘euro effect’ on trade so small after all? New evidence using gravity equations with panel cointegration techniques
2014
In this paper we present new evidence on the aggregate effect of the euro on trade using data for 26 OECD countries for the period 1967–2008. We strive to fill the gaps present in the previous literature through a second-generation panel cointegration tests and estimators that account for both cross-section dependence in the data and discontinuities in the deterministic and the cointegrating vector in the time dimension. This approach allows us to put the adoption of the euro by EMU members in historical perspective. We argue that the creation of the EMU is best interpreted as a progression of policy changes. Once we control for all of them the euro effect decreases considerably but is stil…
The effect of the great recession on foreign direct investment: global empirical evidence with a gravity approach
2013
This article estimates the effect of the present global systemic banking crisis on foreign direct investment (FDI) using the gravity equation on a sample of 161 countries over the period 2003 to 2010. Systemic banking crises, through demand shocks and credit constraints, may impact FDI in two ways: aggregate monetary flows and individual projects count. Since gravity equations account for output variations, our research relies on the financial constraints channel. We find that the great recession, through credit constraints on home supply markets, has reduced the number of FDI projects, but not their size, forcing investors to become more selective on their international endeavours.
Estimating the gravity equation with the actual number of exporting firms
2013
Para estimar correctamente el efecto de los costes de comerciar sobre las exportaciones de las empresas, la ecuación de gravedad debe controlar por el número de empresas que opera en el mercado internacional. Debido a la ausencia de datos, estudios anteriores han controlado esta variable mediante técnicas econométricas que también pueden generar estimaciones sesgadas. Para superar estos problemas este trabajo estima una ecuación de gravedad utilizando una nueva base de datos de la OCDE y EUROSTAT , que incluye el número de empresas exportadoras en cada relación bilateral. Nuestros resultados muestran que no controlar el margen extensivo genera sesgos muy importantes en la estimación de los …
Segmental contribution to forces in vertical jump.
1978
Performance of a vertical jump was analyzed with respect to the contribution of the different body segments to the forces acting on the whole body center of gravity. Both cinematograph and force-platform techniques were employed. The data disclosed that the take-off velocity in vertical jumps was caused by the different components as follows: knee extension 56%, plantar flexion 22%, trunk extension 10%, arm swing 10%, and head swing 2%. However, the average take-off velocity of the total performance (3.03 m/s) was only 76% from the theoretical maximum calculated from the segmental analyses. Optimal timing of the segmental performances was calculated to increase this “efficiency” to 84%. Gre…
Arm end-point trajectories under normal and micro-gravity environments.
2001
Abstract The purpose of the present experiment was to study the way in which the CNS represents gravitational force during vertical arm pointing movements. Movements in upward and downward directions were executed by two cosmonauts in normal-gravity and weightlessness. Analyses focused upon finger kinematics in the sagittal plane. In normal-gravity, downward direction movements showed smaller curvatures and greater relative times to peak velocity ( AT MT ) when compared with upward direction movements. Data from the weightlessness experiments showed that whilst downward movements decreased their curvature during space flight, curvatures of upward movements changed slightly. Furthermore, AT …
Effects of Rapid Weight Loss on Kidney Function in Combat Sport Athletes
2021
Even though scientific literature shows numerous heath complications and performance decrements associated with rapid weight loss (RWL), its prevalence remains exceedingly high across various combat sports. The aim of this study was to thoroughly search the existing literature to explore the influence of RWL on kidney function in Olympic and non-Olympic combat sport athletes. PubMed and Web of Science were searched for the relevant studies. Only original articles published from 2005 onwards, written in English, that included healthy males and females who prompted ~5% weight loss within a week or less, were included in the study. Retrieved studies showed that creatinine, blood urea nitrogen …
Initial information prior to movement onset influences kinematics of upward arm pointing movements
2016
International audience; To elaborate a motor plan and perform online control in the gravity field, the brain relies on priors and multisensory integration of information. In particular, afferent and efferent inputs related to the initial state are thought to convey sensorimotor information to plan the upcoming action. Yet it is still unclear to what extent these cues impact motor planning. Here we examined the role of initial information on the planning and execution of arm movements. Participants performed upward arm movements around the shoulder at three speeds and in two arm conditions. In the first condition, the arm was outstretched horizontally and required a significant muscular comm…
''Active Collisions in Altered Gravity Reveal Eye-Hand Coordination Strategies''
2012
White, Olivier | Lefevre, Philippe | Wing, Alan M. | Bracewell, R. Martyn | Thonnard, Jean-Louis; International audience; ''Most object manipulation tasks involve a series of actions demarcated by mechanical contact events, and gaze is usually directed to the locations of these events as the task unfolds. Typically, gaze foveates the target 200 ms in advance of the contact. This strategy improves manual accuracy through visual feedback and the use of gaze-related signals to guide the hand/ object. Many studies have investigated eye-hand coordination in experimental and natural tasks; most of them highlighted a strong link between eye movements and hand or object kinematics. In this experime…