771 resultados para African refugees and migrants


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[EN] Seagrass meadows are deteriorating worldwide. However, numerous declines are still unreported, which avoid accurate evaluations of seagrass global trends. This is particularly relevant for the western African coast and nearby oceanic archipelagos in the eastern Atlantic. The seagrass Cymodocea nodosa is an ecological engineer on shallow soft bottoms of the Canary Islands. A comparative decadal study was conducted in 21 C. nodosa seagrass meadows at Gran Canaria Island to compare the structure (shoot density, leaf length and cover) between 2003 and 2012. Overall, 11 meadows exhibited a severe regression, while 10 remained relatively stable. During this period, natural influences (sea surface temperature, Chlorophyll-a concentration and PAR light, as well as the number of storm episodes detaching seagrasses) had a low predictive power on temporal patterns in seagrass structure. In contrast, proximity from a range of human-mediated influences (e.g. the number of outfalls and ports) seem to be related to the loss of seagrass; the rate of seagrass erosion between 2003 and 2012 was significantly predicted by the number of human-mediated impacts around each meadow. This result highlights promoting management actions to conserve meadows of C. nodosa at the study region through efficient management of local impacts

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[ES] Cada uno de los pueblos negro-africanos presenta un perfil cultural que le hace ser singular y esencialmente semejante a otros, como parte importante de un todo cultural, algunas veces difícil de determinar explícitamente. Los procesos que definían a los negro-africanos experimentaron una acelerada transformación debido al choque cultural que vivieron durante casi cinco siglos de su historia. Este choque debilitó sus estructuras culturales, creando Estados con lenguas extranjeras oficiales, religiones de importación, escuelas desvernacularizadas, etc., y desplazando los tradicionales sistemas sociopolíticos negro-africanos. Esta fuerte aculturación del África negra se ve fortalecida por la dominancia de la cultura exógena, que impide la reconfiguración etnocultural de sus habitantes y sociedades. Este es el gran reto de su futuro: fortalecer sus diversidades y enseñar a sus habitantes a aprender a ser africanos.

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[POR] Partindo do pressuposto de que a ideia de África é, em muito, devedora do entendimento que os nacionalistas africanos tinham das suas sociedades, discute-se o contributo específico de três nacionalistas, conquanto um deles, Frantz Fanon não seja de origem africana, mas sim antilhana. O nacionalismo é, neste contexto, entendido como parte de um movimento mais vasto, o do renascimento africano, ciclicamente evocado pelos líderes africanos e, deste modo, entendido como um movimento de longa duração (longue durée).

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This dissertation presents for the first time a survey of bird pollinated (ornithophilous) Salvia species. Within the approximately 1000 species of the worldwide distributed genus roughly 20% (186 spp.) are bird pollinated. Excepting four species in the Old World (South Africa and Madagascar), ornithophilous species are restricted to the New World where they represent about one third of the species. They occur mainly in higher altitudes (1500-3000m) and usually grow as shrubs or perennial herbs (97%). The bilabiate to tubular flowers are often red (at least 49%), averaging 35mm (7-130mm) in length and produce a large to medium volume of nectar with rather low sugar concentration. Pollination by sunbirds and white-eyes is documented in a South African species, and that by hummingbirds in 16 species of the New World (USA, Mexico, Guatemala and Bolivia). Beside pollinator observations, the functionality of the staminal levers, the process of pollen transfer and the fitting between flowers and birds are tested by inserting museum skins and metal rods into fresh flowers. The most surprising result is the finding of two different main pollen transfer mechanisms. In at least 54% of the species an active staminal lever mechanism enables pollen deposition on the birds body. This is illustrated in detail in the South African S. lanceolata at which birds were observed to release the lever mechanism and became dusted with pollen. In contrast, the lever mechanism in about 35% of the New World species is reduced in different ways. Pollen transfer by inactive ‘levers’ is demonstrated in detail in S. haenkei in Bolivia, at which four pollinating hummingbird species could be observed. The tubular corolla forced the birds in a specific position, thereby causing pollen transfer from the exserted pollen-sacs to the birds body. With respect to the floral diversity and systematic affiliation of the species, parallel evolution of ornithophily and lever reduction is likely. Considering that bird pollinated species might have derived from bee pollinated species and that the staminal levers have become secondarily inactive, it is concluded that the shift in pollinators induced phenotypic changes even disabling such a sophisticated structure as the staminal lever mechanism.

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L’impegno civile di Umberto Zanotti Bianco (1889-1963) intrecciandosi ai principali eventi storici della prima metà del Novecento ha concorso a fare del Mezzogiorno d’Italia un laboratorio per una concreta emancipazione delle fasce sociali più umili. In queste coordinate l’azione di Zanotti Bianco è emblematica: supera la visione conservatrice di un sud incapace di fare emergere saperi e capacità organizzative mirando invece attraverso chiari, determinati e moderni progetti di riforma a far crescere il lievito della consapevolezza e della capacità di governarsi. Si può legittimamente sostenere che la complessa azione di Zanotti Bianco, pur partendo dalle migliori e più avanzate forme del pensiero meridionalista di inizio secolo, nella pratica tende a superare anche queste collocando la questione del Mezzogiorno d’Italia non solo nello scenario nazionale, tipico della fondamentale e già innovativa riflessione intorno al sud sviluppatasi da Villari a Salvemini, ma proietta le problematiche del meridione all’interno di un quadro europeo con una spiccata vocazione mediterranea. In sostanza i piani dell’intervento sociale, studiati e messi a punto inizialmente in Calabria e nelle regioni economicamente depresse del nostro Mezzogiorno, per Zanotti Bianco sembrano essere da modello anche per le più complesse questioni sociali di altri popoli del bacino del Mediterraneo i quali (come le popolazioni dell’Italia meridionale in quegli anni) apparivano deficitarii di strumenti per lo sviluppo economico, sociale, politico: è questa la tesi qui proposta.

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Epigenetic variability is a new mechanism for the study of human microevolution, because it creates both phenotypic diversity within an individual and within population. This mechanism constitutes an important reservoir for adaptation in response to new stimuli and recent studies have demonstrated that selective pressures shape not only the genetic code but also DNA methylation profiles. The aim of this thesis is the study of the role of DNA methylation changes in human adaptive processes, considering the Italian peninsula and macro-geographical areas. A whole-genome analysis of DNA methylation profile across the Italian penisula identified some genes whose methylation levels differ between individuals of different Italian districts (South, Centre and North of Italy). These genes are involved in nitrogen compound metabolism and genes involved in pathogens response. Considering individuals with different macro-geographical origins (individuals of Asians, European and African ancestry) more significant DMRs (differentially methylated regions) were identified and are located in genes involved in glucoronidation, in immune response as well as in cell comunication processes. A "profile" of each ancestry (African, Asian and European) was described. Moreover a deepen analysis of three candidate genes (KRTCAP3, MAD1L and BRSK2) in a cohort of individuals of different countries (Morocco, Nigeria, China and Philippines) living in Bologna, was performed in order to explore genetic and epigenetic diversity. Moreover this thesis have paved the way for the application of DNA methylation for the study of hystorical remains and in particular for the age-estimation of individuals starting from biological samples (such as teeth or blood). Noteworthy, a mathematical model that considered methylation values of DNA extracted from cementum and pulp of living individuals can estimate chronological age with high accuracy (median absolute difference between age estimated from DNA methylation and chronological age was 1.2 years).

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In diesem Arbeitspapier will ich zur künftigen Forschung über soziale Stratifikation in Afrika beitragen, indem ich die theoretischen Implikationen und empirischen Herausforderungen der Konzepte "Elite" und "Mittelklasse" untersuche. Diese Konzepte stammen aus teilweise miteinander konkurrierenden Theorietraditionen. Außerdem haben Sozialwissenschaftler und Historiker sie zu verschiedenen Zeiten und mit Bezug auf verschiedene Regionen unterschiedlich verwendet. So haben Afrikaforscher und -forscherinnen soziale Formationen, die in anderen Teilen der Welt als Mittelklasse kategorisiert wurden, meist als Eliten aufgefasst und tun dies zum Teil noch heute. Elite und Mittelklasse sind aber nicht nur Begriffe der sozialwissenschaftlichen Forschung, sondern zugleich Kategorien der sozialen und politischen Praxis. Die Art und Weise, wie Menschen diese Begriffe benutzen, um sich selbst oder andere zu beschreiben, hat wiederum Rückwirkungen auf sozialwissenschaftliche Diskurse und umgekehrt. Das Arbeitspapier setzt sich mit beiden Aspekten auseinander: mit der Geschichte der theoretischen Debatten über Elite und Mittelklasse und damit, was wir aus empirischen Studien über die umstrittenen Selbstverortungen sozialer Akteure lernen können und über ihre sich verändernden Auffassungen und Praktiken von Elite- oder Mittelklasse-Sein. Weil ich überzeugt bin, dass künftige Forschung zu sozialer Stratifikation in Afrika außerordentlich viel von einer historisch und regional vergleichenden Perspektive profitieren kann, analysiert dieses Arbeitspapier nicht nur Untersuchungen zu afrikanischen Eliten und Mittelklassen, sondern auch eine Fülle von Studien zur Geschichte der Mittelklassen in Europa und Nordamerika sowie zu den neuen Mittelklassen im Globalen Süden.

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Control of contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC), remains an important goal in Africa. Subunit vaccines triggering B and T-cell responses could represent a promising approach. To this aim, the T-cell immunogenicity of four MmmSC lipoproteins (LppA, LppB, LppC and LppQ), present in African strains and able to elicit humoral response, was evaluated. In vitro assays revealed that only LppA was recognized by lymph node lymphocytes taken from three cattle, 3 weeks after MmmSC exposure. Maintenance of the LppA-specific response, relying on CD4 T-cells and IFN gamma production, was then demonstrated 1 year after infection. LppA is thus an important target for the CD4 T-cells generated early after MmmSC infection and persisting in the lymph nodes of recovered cattle. Its role as a protective antigen and ability to in vivo trigger both arms of the host immune response remain to be evaluated.

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This thesis will cover sports controversies throughout the 20th Century in the context of the media’s newspaper coverage of the events. The 1919 Black Sox Scandal, the debate over American participation in the 1936 Olympics, and Muhammad Ali’s conversion to the Nation of Islam, standing as a notorious public figure, and conscientious objection to the Vietnam War will represent the three sports controversies. The media’s adherence to cultural norms is clear in all three cases. The consistent devotion to the cultural and racial atmosphere of their respective eras was constant and helped to perpetuate accepted, mainstream cultural attitudes. Cultural and racial norms were followed in the coverage of the three discussed controversies. The anti-Semitism and racially intolerant sentiments in America during great waves of immigration in the early 1900s allowed for journalists to freely vilify Jews as corrupters of baseball and the ballplayers who were rumored to have thrown the 1919 World Series. The white ballplayers were supported in the press, who protected their own and blamed outsiders. Jim Crow and the Americanization movement forced African American and Jewish newspapers to limit their journalistic bias on both sides of the debate over American participation in the 1936 Berlin Olympics. The white, mainstream press was void of bias as the spirit of isolationism in America triumphed over journalist’s leanings in the Olympic debate. The racial tension created by the Civil Rights movement of the 1960s created an atmosphere that allowed mainstream journalists to heap endless criticism on Muhammad Ali as he gained fame. By portraying him as a villain of society as both a religious radical and traitor to America, journalists created a common enemy in the minds of white America. In all three cases, a pattern of journalists expressing the state of cultural and racial norms of the era is present and significant.

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In June of 2010, at the African American and Juneteenth Festival in Worcester, Massachusetts, Clark University administered a survey directed toward African American residents of the city of Worcester. In the survey, residents who attended the festival were asked to rate the quality of life in the City, public services, and local government and political representation, as well as leadership in the local African-American community. This report presents and analyzes the primary findings of the survey.

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Trypanosoma brucei encodes a relatively high number of genes of the equilibrative nucleoside transporter (ENT) family. We report here the cloning and in-depth characterization of one T. brucei brucei ENT member, TbNT9/AT-D. This transporter was expressed in Saccharomyces cerevisiae and displayed a uniquely high affinity for adenosine (Km = 0.068 +/- 0.013 microM), as well as broader selectivity for other purine nucleosides in the low micromolar range, but was not inhibited by nucleobases or pyrimidines. This selectivity profile is consistent with the P1 transport activity observed previously in procyclic and long-slender bloodstream T. brucei, apart from the 40-fold higher affinity for adenosine than for inosine. We found that, like the previously investigated P1 activity of long/slender bloodstream trypanosomes, the 3'-hydroxy, 5'-hydroxy, N3, and N7 functional groups contribute to transporter binding. In addition, we show that the 6-position amine group of adenosine, but not the inosine 6-keto group, makes a major contribution to binding (DeltaG0 = 12 kJ/mol), explaining the different Km values of the purine nucleosides. We further found that P1 activity in procyclic and long-slender trypanosomes is pharmacologically distinct, and we identified the main gene encoding this activity in procyclic cells as NT10/AT-B. The presence of multiple P1-type nucleoside transport activities in T. brucei brucei facilitates the development of nucleoside-based treatments for African trypanosomiasis and would delay the onset of uptake-related drug resistance to such therapy. We show that both TbNT9/AT-D and NT10/AT-B transport a range of potentially therapeutic nucleoside analogs.

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An appropriate model of recent human evolution is not only important to understand our own history, but it is necessary to disentangle the effects of demography and selection on genome diversity. Although most genetic data support the view that our species originated recently in Africa, it is still unclear if it completely replaced former members of the Homo genus, or if some interbreeding occurred during its range expansion. Several scenarios of modern human evolution have been proposed on the basis of molecular and paleontological data, but their likelihood has never been statistically assessed. Using DNA data from 50 nuclear loci sequenced in African, Asian and Native American samples, we show here by extensive simulations that a simple African replacement model with exponential growth has a higher probability (78%) as compared with alternative multiregional evolution or assimilation scenarios. A Bayesian analysis of the data under this best supported model points to an origin of our species approximately 141 thousand years ago (Kya), an exit out-of-Africa approximately 51 Kya, and a recent colonization of the Americas approximately 10.5 Kya. We also find that the African replacement model explains not only the shallow ancestry of mtDNA or Y-chromosomes but also the occurrence of deep lineages at some autosomal loci, which has been formerly interpreted as a sign of interbreeding with Homo erectus.