10 resultados para Arabic literature--Africa, North

em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain


Relevância:

100.00% 100.00%

Publicador:

Resumo:

S'han estudiat els nombres cromosómics i l'estructura dels cariotipus de 15 poblacions nordafricanes de Delphinium L. sect. Delphinium. Delphinium balansae Boiss. & Reuter, amb cariotipus mes simétric, apareix com a possible ancestre perenne de la resta d'espécies annuals amb cariotipus mes asimétric i mes curt. Es proposa una reorganització taxonómica de la secció, d'on es descriuen dues series noves (ser. Macropeiala ser. nova i ser. Balansae ser. nova.) i es proposen dues combinacions noves (D. nanum subsp. alboliliaceum i D. nanum subsp. elongatum).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

One of the main findings derived from the analysis of the Neandertal genome was the evidence for admixture between Neandertals and non-African modern humans. An alternative scenario is that the ancestral population of non-Africans was closer to Neandertals than to Africans because of ancient population substructure. Thus, the study of North African populations is crucial for testing both hypotheses. We analyzed a total of 780,000 SNPs in 125 individuals representing seven different North African locations and searched for their ancestral/derived state in comparison to different human populations and Neandertals. We found that North African populations have a significant excess of derived alleles shared with Neandertals, when compared to sub-Saharan Africans. This excess is similar to that found in non-African humans, a fact that can be interpreted as a sign of Neandertal admixture. Furthermore, the Neandertal's genetic signal is higher in populations with a local, pre-Neolithic North African ancestry. Therefore, the detected ancient admixture is not due to recent Near Eastern or European migrations. Sub-Saharan populations are the only ones not affected by the admixture event with Neandertals.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In recent years, new analytical tools have allowed researchers to extract historical information contained in molecular data, which has fundamentally transformed our understanding of processes ruling biological invasions. However, the use of these new analytical tools has been largely restricted to studies of terrestrial organisms despite the growing recognition that the sea contains ecosystems that are amongst the most heavily affected by biological invasions, and that marine invasion histories are often remarkably complex. Here, we studied the routes of invasion and colonisation histories of an invasive marine invertebrate Microcosmus squamiger (Ascidiacea) using microsatellite loci, mitochondrial DNA sequence data and 11 worldwide populations. Discriminant analysis of principal components, clustering methods and approximate Bayesian computation (ABC) methods showed that the most likely source of the introduced populations was a single admixture event that involved populations from two genetically differentiated ancestral regions - the western and eastern coasts of Australia. The ABC analyses revealed that colonisation of the introduced range of M. squamiger consisted of a series of non-independent introductions along the coastlines of Africa, North America and Europe. Furthermore, we inferred that the sequence of colonisation across continents was in line with historical taxonomic records - first the Mediterranean Sea and South Africa from an unsampled ancestral population, followed by sequential introductions in California and, more recently, the NE Atlantic Ocean. We revealed the most likely invasion history for world populations of M. squamiger, which is broadly characterized by the presence of multiple ancestral sources and non-independent introductions within the introduced range. The results presented here illustrate the complexity of marine invasion routes and identify a cause-effect relationship between human-mediated transport and the success of widespread marine non-indigenous species, which benefit from stepping-stone invasions and admixture processes involving different sources for the spread and expansion of their range.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

El WP té com a objectiu examinar per què els països del nord d'Àfrica estan augmentant les seves importacions de Xina i per què la Xina està augmentant les seves inversions estrangeres directes a la zona. la avantatges per als països del nord d'Àfrica es troben en els actuals acords de lliure comerç, el absència de barreres aranzelàries i la seva ubicació geogràfica summament beneficiosa com Hub de la Mediterrània. El paper de la Unió per la Mediterrània és clau per identificar aspectes de la política regional, tenint en compte la participació xinesa a la zona. com conseqüència, concloem que els actors polítics han de trobar un equilibri entre sostenible desenvolupament i els interessos econòmics de la regió.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The Barcelona Euro-Mediterranean Conference (1995) was intended to be a launching pad" for creating a new, innovative relationship between the EU-Fifteen and a selected set of non-member Middle Eastern and North African countries. The Barcelona Process was to become the European Union´s first attempt, of several, to create postmodern inclusive policy spheres as a way to deal with the post-enlargement problems of ´ins´ and outs´ in its immediate periphery. Nevertheless, in spite of geographical proximity, common problems and stated interest in creating amorphous EU borders in different sectors, the Euro-Mediterranean Partnership is today all but abandoned. This paper will examine some of the factors behind the current degeneration of the EU´s post-bipolar foreign policy strategy in the Mediterranean, by exploring the dialectic between the Union´s desire to expand its geopolitical, economic and cultural boundaries and the need to secure its territorial area (from migration, proliferation, social instability etc.). In the final part of the paper some suggestions for how to revive the relationship across the Mare Nostrum will be forwarded.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In a world where poor countries provide weak protection for intellectual property rights (IPRs), market integration shifts technical change in favor of rich nations. Through this channel, free trade may amplify international income differences. At the same time, integration with countries where IPRs are weakly protected can slow down the world growth rate. An important implication of these results is that protection of intellectual property is most beneficial in open countries. This prediction, which is novel in the literature, is consistent with evidence from a panel of 53 countries observed in the years 1965-1990. The paper also provides empirical support for the mechanism linking North-South trade to the direction of technical change: an increase in import penetration from low-wage, low-IPRs, countries is followed by a sharp fall in R&D investment in a panel of US manufacturing sectors.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In a world where poor countries provide weak protection for intellectual propertyrights, market integration shifts technical change in favor of rich nations. Throughthis channel, free trade may amplify international income differences. At the sametime, integration with countries where intellectual property rights are weakly protectedcan slow down the world growth rate. A crucial implication of these results is thatprotection of intellectual property is most beneficial in open countries. This prediction,which is novel in the literature, finds support in the data on a panel of 53 countriesobserved in the years 1965-1990.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Abstract. The ability of 2 Rapid Bioassessment Protocols (RBPs) to assess stream water quality was compared in 2 Mediterranean-climate regions. The most commonly used RBPs in South Africa (SAprotocol) and the Iberian Peninsula (IB-protocol) are both multihabitat, field-based methods that use macroinvertebrates. Both methods use preassigned sensitivity weightings to calculate metrics and biotic indices. The SA- and IB-protocols differ with respect to sampling equipment (mesh size: 1000 lm vs 250 300 lm, respectively), segregation of habitats (substrate vs flow-type), and sampling and sorting procedures (variable time and intensity). Sampling was undertaken at 6 sites in South Africa and 5 sites in the Iberian Peninsula. Forty-four and 51 macroinvertebrate families were recorded in South Africa and the Iberian Peninsula, respectively; 77.3% of South African families and 74.5% of Iberian Peninsula families were found using both protocols. Estimates of community similarity compared between the 2 protocols were .60% similar among sites in South Africa and .54% similar among sites in the Iberian Peninsula (BrayCurtis similarity), and no significant differences were found between protocols (Multiresponse Permutation Procedure). Ordination based on Non-metric Multidimensional Scaling grouped macroinvertebrate samples on the basis of site rather than protocol. Biotic indices generated with the 2 protocols at each site did not differ. Thus, both RBPs produced equivalent results, and both were able to distinguish between biotic communities (mountain streams vs foothills) and detect water-quality impairment, regardless of differences in sampling equipment, segregation of habitats, and sampling and sorting procedures. Our results indicate that sampling a single habitat may be sufficient for assessing water quality, but a multihabitat approach to sampling is recommended where intrinsic variability of macroinvertebrate assemblages is high (e.g., in undisturbed sites in regions with Mediterranean climates). The RBP of choice should depend on whether the objective is routine biomonitoring of water quality or autecological or faunistic studies.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The calculation of time prayer is a key element of the Islam. Therefore specialists in this field, the muwaqqits, appeared. In al-Andalus and the Magrib there are a great number of scholars, some of which, like al-Mu"addib and al-Tájúrí are good examples of the literature that they generated.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

An annual-resolved precipitation reconstruction for the last 800 yr in Southern Spain has been performed using stable carbon isotope (δ13C) of Pinus nigra tree rings. The reconstruction exhibits high- to low-frequency variability and distinguishes a Little Ice Age (LIA, AD 13501850) characterized by lower averaged rainfall than both in the transition from the Medieval Climate Anomaly to the LIA and in the 20th century. The driest conditions are recorded during the Maunder solar Minimum (mid 17thearly 18th centuries), in good agreement with the Spanish documentary archive. Similar linkage between solar activity (maximum/minimum) and precipitation (increase/decrease) is observed throughout the entire LIA. Additionally, the relationship between the hydrological pattern in the Iberian Peninsula and Morocco during the LIA suggests different spatial distribution of precipitation in the south-eastern sector of the North Atlantic region such as it is known currently. Whereas in the instrumental record the precipitation evolves similarly in both regions and opposite to the North Atlantic oscillation (NAO) index, the coldest periods of the LIA shows a contrasting pattern with drier conditions in the South of Spain and wetter in Northern Africa. We suggest an extreme negative NAO conditions, accompanied by a southward excursion of the winter rainfall band beyond that observed in the last century, can explain this contrast. The sustained NAO conditions could have been triggered by solar minima and higher volcanic activity during the LIA.