Search results for "cycle"
showing 10 items of 3119 documents
Cycles diurnes de rayonnement solaire et forets en Afrique Centrale.
2018
The sunlightconditions prevailing in Central Africa, and their potential impact on forests traits and functioning, have neverbeen fully explored. Using satellite estimates documenting mostly the period 2005-2013, and accounting forscale interactions between the diurnal and annual cycles, we demonstrate that the seasonality of sunlight levelsstrongly vary across Central Africa forests. Gabon stands out with a main dry season strongly light-deficient,cool and moist. An original map of terra firme forest types developed by CIRAD shows that most of theevergreen forests of Central Africa develop in Gabon. We postulate that despite a mean annual precipitationamount below 2000 mm/yr, the Gabonese …
Theoretical space-time modelling of the diffusion of raw materials and manufactured objects
2013
International audience; Workgroup 3 of ArchaeDyn II programme focuses its study on the diffusion systems of ancient products. In order to be able to structure data in GIS in an appropriate way, we propose a general theoretical modelling integrating the different components of the diffusion systems, and identifying their interactions and the factors affecting the location of products and their transfers. Three dimensions are considered: the Time, the Space and the Function of places. A product's pathway can be apprehended efficiently by distinguishing spatial entities as well as functional entities. This modelling highlights the fact that the approach through the simple notion of "site" is n…
Review of the methods for the development of information security policies at organizations
2016
This thesis aims to have an overview of the current studies in the development of information security policy. The research is based on a systematical literature review. The study focuses on the development process of information security policy and other relevant issues in information security policy development within organizations. There are four research questions are proposed based on this topic: 1) what are the functions of information security policy; 2) what kind of stakeholders should be involved in the development of information security policy; 3) what is the information security policy lifecycle; 4) what are the methods in development of information security policy. The research…
The anthropogenic sealing of soils in urban areas
2009
The sealing of soils by impervious materials is, normally, detrimental to its ecological functions. Exchanges of energy, water and gases are restricted or hampered and an increasing pressure is being exerted on adjacent, non sealed areas. The negative effects span from loss of plant production and natural habitats to increased floods, pollution, and health risks and consequently higher social costs. Environmental Agencies produce periodical reports where the phenomenon of soil consumption by urban infrastructures is monitored with extremely sophisticated geographical tools but little specific research is available that describes the effects of soil sealing. This paper reviews some recent co…
Preliminary Experimental Study on Double Fuel HCCI Combustion
2015
AbstractThis paper regards an experimental study on a particular internal combustion engine process which combines Double Fuel combustion with Homogeneous Charge Compression Ignition (HCCI) using mixtures of natural gas (NG) and gasoline. The tests performed on a CFR engine demonstrate that HCCI combustion can be achieved using NG-gasoline mixtures without knocking occurrence for low to medium engine load varying the proportion between the two fuels. The main advantage of this new combustion process relies on the noticeable higher engine efficiency obtained with respect to conventional spark ignition operation, and on the strong reduction of NOX emissions.
Computational Experiments with the Roots of Fibonacci-like Polynomials as a Window to Mathematics Research
2022
Fibonacci-like polynomials, the roots of which are responsible for a cyclic behavior of orbits of a second-order two-parametric difference equation, are considered. Using Maple and Wolfram Alpha, the location of the largest and the smallest roots responsible for the cycles of period p among the roots responsible for the cycles of periods 2kp (period-doubling) and kp (period-multiplying) has been determined. These purely computational results of experimental mathematics, made possible by the use of modern digital tools, can be used as a motivation for confirmation through not-yet-developed methods of formal mathematics. peerReviewed
The closure of Pak1-dependent macropinosomes requires the phosphorylation of CtBP1/BARS
2007
Membrane fission is an essential process in membrane trafficking and other cellular functions. While many fissioning and trafficking steps are mediated by the large GTPase dynamin, some fission events are dynamin independent and involve C-terminal-binding protein-1/brefeldinA-ADP ribosylated substrate (CtBP1/BARS). To gain an insight into the molecular mechanisms of CtBP1/BARS in fission, we have studied the role of this protein in macropinocytosis, a dynamin-independent endocytic pathway that can be synchronously activated by growth factors. Here, we show that upon activation of the epidermal growth factor receptor, CtBP1/BARS is (a) translocated to the macropinocytic cup and its surroundi…
In vitro evaluation of toxic effects, bioavailability and bioaccesibility of beauvericin, enniatins and fusaproliferin = Evaluación in vitro de los e…
2013
Los hongos de Fusarium pueden producir micotoxinas hexadepsipeptidicas, como beauvericina (BEA) y eniatinas (ENs) e isoprenoides como la fusaproliferina (FUS), las cuales se encuentran de forma natural en los alimentos y piensos. En las últimas décadas se han publicado datos, aunque escasos, sobre su toxicidad potencial en humanos y animales. Los objectivos de esta tesis fueron evaluar: los efectos citotóxicos de las FUS, BEA y ENs A, A1, B y B1 en células Caco-2, CHO-K1 y HT-29; los efectos citotóxicos de las ENs combinadas, la generación de especies reactivas de oxígeno (ROS) y la producción de peroxidación lipídica (LPO) tras exposición a FUS, BEA y ENs en las células Caco-2; la citoprot…
New lithostratigraphy for the Cantabrian Mountains: A common tectono-stratigraphic evolution for the onset of the Alpine cycle in the W Pyrenean real…
2019
The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary ph…
Glacier drainage and sandur formation at Kötlujökull, South Iceland
1985
Abstract Over a number of years research on a stretch of the southeastern glacier margin of Kotlujokull in South Iceland, 8 km in length, has focused on correlating the manner of glacier drainage with the genesis of sandar, exemplified by the recent evolution of the glacier foreland. The research has yielded the following results. During an initial period, beginning prior to 1945 and ending between 1966 and 1975, a belt of moraines about 1 km wide was destroyed in stages, except for a few remnants, by 11 outbreaks of subglacial meltwater at different times and locations along the glacier front. These outbursts were associated with the genesis of “ordinary”; sandar, which are referred to her…