982 resultados para Statistics of extremes


Relevância:

90.00% 90.00%

Publicador:

Resumo:

Climate variability and changes in the frequency of extremes events have a direct impact on crop damages and yield. In a former work of Capa et al. (2013) the crop yield variability has been studied using different reanalyses datasets with the aim of extending the time series of potential yield. The reliability of these time series have been checked using observational data. The influence of the sea surface temperature on the crop yield variability has been studied, finding a relation with El Niño phenomenon. The highest correlation between El Niño and yield was during 1960-1980. This study aims to analyse the dynamical mechanism of El Niño impacts on maize yield in Spain during 1960-1980 by comparison with atmospheric circulation patterns.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The different theoretical models related with storm wave characterization focus on determining the significant wave height of the peak storm, the mean period and, usually assuming a triangle storm shape, their duration. In some cases, the main direction is also considered. Nevertheless, definition of the whole storm history, including the variation of the main random variables during the storm cycle is not taken into consideration. The representativeness of the proposed storm models, analysed in a recent study using an empirical maximum energy flux time dependent function shows that the behaviour of the different storm models is extremely dependent on the climatic characteristics of the project area. Moreover, there are no theoretical models able to adequately reproduce storm history evolution of the sea states characterized by important swell components. To overcome this shortcoming, several theoretical storm shapes are investigated taking into consideration the bases of the three best theoretical storm models, the Equivalent Magnitude Storm (EMS), the Equivalent Number of Waves Storm (ENWS) and the Equivalent Duration Storm (EDS) models. To analyse the representativeness of the new storm shape, the aforementioned maximum energy flux formulation and a wave overtopping discharge structure function are used. With the empirical energy flux formulation, correctness of the different approaches is focussed on the progressive hydraulic stability loss of the main armour layer caused by real and theoretical storms. For the overtopping structure equation, the total volume of discharge is considered. In all cases, the results obtained highlight the greater representativeness of the triangular EMS model for sea waves and the trapezoidal (nonparallel sides) EMS model for waves with a higher degree of wave development. Taking into account the increase in offshore and shallow water wind turbines, maritime transport and deep vertical breakwaters, the maximum wave height of the whole storm history and that corresponding to each sea state belonging to its cycle's evolution is also considered. The procedure considers the information usually available for extreme waves' characterization. Extrapolations of the maximum wave height of the selected storms have also been considered. The 4th order statistics of the sea state belonging to the real and theoretical storm have been estimated to complete the statistical analysis of individual wave height

Relevância:

90.00% 90.00%

Publicador:

Resumo:

A method is presented for computing the average solution of problems that are too complicated for adequate resolution, but where information about the statistics of the solution is available. The method involves computing average derivatives by interpolation based on linear regression, and an updating of a measure constrained by the available crude information. Examples are given.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The SWISS-PROT group at EBI has developed the Proteome Analysis Database utilising existing resources and providing comparative analysis of the predicted protein coding sequences of the complete genomes of bacteria, archaea and eukaryotes (http://www.ebi.ac.uk/proteome/). The two main projects used, InterPro and CluSTr, give a new perspective on families, domains and sites and cover 31–67% (InterPro statistics) of the proteins from each of the complete genomes. CluSTr covers the three complete eukaryotic genomes and the incomplete human genome data. The Proteome Analysis Database is accompanied by a program that has been designed to carry out InterPro proteome comparisons for any one proteome against any other one or more of the proteomes in the database.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Polyethylene chains in the amorphous region between two crystalline lamellae M unit apart are modeled as random walks with one-step memory on a cubic lattice between two absorbing boundaries. These walks avoid the two preceding steps, though they are not true self-avoiding walks. Systems of difference equations are introduced to calculate the statistics of the restricted random walks. They yield that the fraction of loops is (2M - 2)/(2M + 1), the fraction of ties 3/(2M + 1), the average length of loops 2M - 0.5, the average length of ties 2/3M2 + 2/3M - 4/3, the average length of walks equals 3M - 3, the variance of the loop length 16/15M3 + O(M2), the variance of the tie length 28/45M4 + O(M3), and the variance of the walk length 2M3 + O(M2).

Relevância:

90.00% 90.00%

Publicador:

Resumo:

We analyzed the photoluminescence intermittency generated by a single paramagnetic spin localized in an individual semiconductor quantum dot. The statistics of the photons emitted by the quantum dot reflect the quantum fluctuations of the localized spin interacting with the injected carriers. Photon correlation measurements, which are reported here, reveal unique signatures of these fluctuations. A phenomenological model is proposed to quantitatively describe these observations, allowing a measurement of the spin dynamics of an individual magnetic atom at zero magnetic field. These results demonstrate the existence of an efficient spin-relaxation channel arising from a spin exchange with individual carriers surrounding the quantum dot. A theoretical description of a spin-flip mechanism involving spin exchange with surrounding carriers gives relaxation times in good agreement with the measured dynamics.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: Map of Hillsboro Co., New Hampshire, from actual surveys by J. Chace, Jr. It was published by Smith, Mason & Co. in 1858. Scale [ca. 1:53,000]. This layer is image 1 of 4 total images, representing the northwest portion of the four sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the New Hampshire State Plane coordinate system (NAD 1983 in Feet) (Fipszone 2800). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town and school district boundaries, and more. Relief shown by hachures. Includes table of distances, agricultural goods, religious affiliations, business directory, statistics of education and other information, and a list of county officers.This layer is part of a selection of digitally scanned and georeferenced historic maps of New England from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates, scales, and map purposes.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: Map of Hillsboro Co., New Hampshire, from actual surveys by J. Chace, Jr. It was published by Smith, Mason & Co. in 1858. Scale [ca. 1:53,000]. This layer is image 2 of 4 total images, representing the southwest portion of the four sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the New Hampshire State Plane coordinate system (NAD 1983 in Feet) (Fipszone 2800). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town and school district boundaries, and more. Relief shown by hachures. Includes table of distances, agricultural goods, religious affiliations, business directory, statistics of education and other information, and a list of county officers.This layer is part of a selection of digitally scanned and georeferenced historic maps of New England from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates, scales, and map purposes.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: Map of Hillsboro Co., New Hampshire, from actual surveys by J. Chace, Jr. It was published by Smith, Mason & Co. in 1858. Scale [ca. 1:53,000]. This layer is image 3 of 4 total images, representing the southeast portion of the four sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the New Hampshire State Plane coordinate system (NAD 1983 in Feet) (Fipszone 2800). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town and school district boundaries, and more. Relief shown by hachures. Includes table of distances, agricultural goods, religious affiliations, business directory, statistics of education and other information, and a list of county officers.This layer is part of a selection of digitally scanned and georeferenced historic maps of New England from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates, scales, and map purposes.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: Map of Hillsboro Co., New Hampshire, from actual surveys by J. Chace, Jr. It was published by Smith, Mason & Co. in 1858. Scale [ca. 1:53,000]. This layer is image 4 of 4 total images, representing the northeast portion of the four sheet source map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the New Hampshire State Plane coordinate system (NAD 1983 in Feet) (Fipszone 2800). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town and school district boundaries, and more. Relief shown by hachures. Includes table of distances, agricultural goods, religious affiliations, business directory, statistics of education and other information, and a list of county officers.This layer is part of a selection of digitally scanned and georeferenced historic maps of New England from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates, scales, and map purposes.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Drawing from confidential firm-level balance sheets in 11 European countries, the paper presents a novel sectoral database of comparable productivity indicators built by members of the Competitiveness Research Network (CompNet) using a newly developed research infrastructure. Beyond aggregate information available from industry statistics of Eurostat or EU KLEMS, the paper provides information on the distribution of firms across several dimensions related to competitiveness, e.g. productivity and size. The database comprises so far 11 countries, with information for 58 sectors over the period 1995-2011. The paper documents the development of the new research infrastructure, the construction of the database, and shows some preliminary results. Among them, it shows that there is large heterogeneity in terms of firm productivity or size within narrowly defined industries in all countries. Productivity, and above all, size distribution are very skewed across countries, with a thick left-tail of low productive firms. Moreover, firms at both ends of the distribution show very different dynamics in terms of productivity and unit labour costs. Within-sector heterogeneity and productivity dispersion are positively correlated to aggregate productivity given the possibility of reallocating resources from less to more productive firms. To this extent, we show how allocative efficiency varies across countries, and more interestingly, over different periods of time. Finally, we apply the new database to illustrate the importance of productivity dispersion to explain aggregate trade results.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

See AGRICULTURE:Animal Production, Statistics of in "EU Annual Reports" below for additional information on this topic.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

See AGRICULTURE:Animal Production, Statistics of in "EU Annual Reports" below for additional information on this topic.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Smart et al. (2014) suggested that the detection of nitrate spikes in polar ice cores from solar energetic particle (SEP) events could be achieved if an analytical system with sufficiently high resolution was used. Here we show that the spikes they associate with SEP events are not reliably recorded in cores from the same location, even when the resolution is clearly adequate. We explain the processes that limit the effective resolution of ice cores. Liquid conductivity data suggest that the observed spikes are associated with sodium or another nonacidic cation, making it likely that they result from deposition of sea salt or similar aerosol that has scavenged nitrate, rather than from a primary input of nitrate in the troposphere. We consider that there is no evidence at present to support the identification of any spikes in nitrate as representing SEP events. Although such events undoubtedly create nitrate in the atmosphere, we see no plausible route to using nitrate spikes to document the statistics of such events.