985 resultados para Black Community


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Parameters of provision of the phytoplankton community with inorganic nitrogen compounds in the western Black Sea in April 1993 are analyzed (specifically, dependence of rates of uptake of nitrates and ammonium by microplankton on substrate concentration, diurnal dynamics of assimilation of mineral nitrogen, values of f-ratios, and proportions of carbon and nitrogen fluxes). In most cases all the parameters of degree of phytoplankton provision with mineral nitrogen are shown to vary unidirectionally, both at the surface and in the photosynthesis zone. Individual areas of a relatively small region studied differed markedly in their level of provision of algae with inorganic nitrogen compounds - from complete saturation to high degree of limitation of phytoplankton development due to nitrogen deficiency in the environment. Obtained results allow to estimate provision of Black Sea phytoplankton with nitrogen in terms of limitation of rates of uptake of its inorganic compounds.

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This article considers the opportunities of civilians to peacefully resist violent conflicts or civil wars. The argument developed here is based on a field-based research on the peace community San José de Apartadó in Colombia. The analytical and theoretical framework, which delimits the use of the term ‘resistance’ in this article, builds on the conceptual considerations of Hollander and Einwohner (2004) and on the theoretical concept of ‘rightful resistance’ developed by O’Brien (1996). Beginning with a conflict-analytical classification of the case study, we will describe the long-term socio-historical processes and the organizational experiences of the civilian population, which favoured the emergence of this resistance initiative. The analytical approach to the dimensions and aims of the resistance of this peace community leads to the differentiation of O`Brian’s concept of ‘rightful resistance’.

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This research examines the process of placemaking in LeDroit Park, a residential Washington, DC, neighborhood with a historic district at its core. Unpacking the entwined physical and social evolution of the small community within the context of the Nation’s Capital, this analysis provides insight into the role of urban design and development as well as historic designation on shaping collective identity. Initially planned and designed in 1873 as a gated suburb just beyond the formal L’Enfant-designed city boundary, LeDroit Park was intended as a retreat for middle and upper-class European Americans from the growing density and social diversity of the city. With a mixture of large romantic revival mansions and smaller frame cottages set on grassy plots evocative of an idealized rural village, the physical design was intentionally inwardly-focused. This feeling of refuge was underscored with a physical fence that surrounded the development, intended to prevent African Americans from nearby Howard University and the surrounding neighborhood, from using the community’s private streets to access the City of Washington. Within two decades of its founding, LeDroit Park was incorporated into the District of Columbia, the surrounding fence was demolished, and the neighborhood was racially integrated. Due to increasingly stringent segregation laws and customs in the city, this period of integration lasted less than twenty years, and LeDroit Park developed into an elite African American enclave, using the urban design as a bulwark against the indignities of a segregated city. Throughout the 20th century housing infill and construction increased density, yet the neighborhood never lost the feeling of security derived from the neighborhood plan. Highlighting the architecture and street design, neighbors successfully received historic district designation in 1974 in order to halt campus expansion. After a stalemate that lasted two decades, the neighborhood began another period of transformation, both racial and socio-economic, catalyzed by a multi-pronged investment program led by Howard University. Through interviews with long-term and new community members, this investigation asserts that the 140-year development history, including recent physical interventions, is integral to placemaking, shaping the material character as well as the social identity of residents.

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This study examines the factors facilitating the transfer admission of students broadly classified as Black from a single community college into a selective engineering college. The work aims to further research on STEM preparation and performance for students of color, as well as scholarship on increasing access to four-year institutions from two-year schools. Factors illuminating Underrepresented Racial and Ethnic Minority (URM) student pathways through Science, Technology, Engineering, and Mathematics (STEM) degree programs have often been examined through large-scale quantitative studies. However, this qualitative study complements quantitative data through demographic questionnaires, as well as semi-structured individual and group. The backgrounds and voices of diverse Black transfer students in four-year engineering degree programs were captured through these methods. Major findings from this research include evidence that community college faculty, peer networks, and family members facilitated transfer. Other results distinguish Black African from Black American transfers; included in these distinctions are depictions of different K-12 schooling experiences and differences in how participants self-identified. The findings that result from this research build upon the few studies that account for expanded dimensions of student diversity within the Black population. Among other demographic data, participants’ countries of birth and years of migration to the U.S. (if applicable) are included. Interviews reveal participants’ perceptions of factors impacting their educational trajectories in STEM and subsequent ability to transfer into a competitive undergraduate engineering program. This study is inclusive of, and reveals an important shifting demographic within the United States of America, Black Africans, who represent one of the fastest-growing segments of the immigrant population.

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Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition fluorescence in situ hybridization (CARD FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased with depths from 10(9) to 10(10) cells/mL at the sediment surface to 10(7)-10(9) cells/mL below one meter depth. Based on CARD FISH and Q-PCR analyses overall similar proportions of Bacteria and Archaea were found. The down-core distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes (16S and 18S rRNA) as well as functional genes involved in different biogeochemical processes was quantified using Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 as well as the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were highly abundant. Less abundant but detectable in most of the samples were Eukarya as well as the metal and sulfate-reducing Geobacteraceae (only in the Benguela upwelling influenced sediments). The functional genes cbbL, encoding for the large subunit of RuBisCO, the genes dsrA and aprA, indicative of sulfate-reducers as well as the mcrA gene of methanogens were detected in the Benguela upwelling and Black Sea sediments. Overall, the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea.

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The aim of this thesis was to quantify experimentally in the field the effects of different timing regimes of hypoxia on the structure of benthic communities in a transitional habitat. The experiment was performed from 8 July to 29 July 2019 in a shallow subtidal area in Pialassa Baiona (Italy), a lagoon characterized by mixing regimes dominated by the tide. The benthic community was isolated using cylinders 15,5Cm x 20Cm size. Hypoxic conditions were imposed by covering the treated cylinders with a black plastic bag while control cylinders were left uncovered. We created 4 different timing regimes of hypoxia by manipulating both the duration of hypoxia (4 or 8 days) as well as the ratio between the duration of subsequent periods of hypoxia and the duration of a normoxic period between subsequent hypoxic events (D4R3/2, D8R3/2). At the end of each experimental trial, the benthic communities within each pot were retrieved, sieved in the field and subsequent analyzed in the laboratory where organisms were identified and counted. Results showed that benthic organism were generally negatively affected by hypoxic stress events. As expected, longer hypoxic events caused a stronger decrease of benthic community abundance. When the hypoxic events were interrupted by the normoxic event there were two different results. If the hypoxic period was too long, the normoxic period didn’t cause a positive recovery effect, and further decline of the benthic community was observed. Conversely normoxia had positive effects if the period of hypoxia was short enough not to compromise the benthic community. This resulted in a statistically significant interaction between the tested factors Duration and Ratio. Amphipods were the most sensitive organisms to hypoxia. We conclude that the effects of hypoxia can be greatly relieved by short normoxic periods if they happen frequently enough.

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Mine drainage is an important environmental disturbance that affects the chemical and biological components in natural resources. However, little is known about the effects of neutral mine drainage on the soil bacteria community. Here, a high-throughput 16S rDNA pyrosequencing approach was used to evaluate differences in composition, structure, and diversity of bacteria communities in samples from a neutral drainage channel, and soil next to the channel, at the Sossego copper mine in Brazil. Advanced statistical analyses were used to explore the relationships between the biological and chemical data. The results showed that the neutral mine drainage caused changes in the composition and structure of the microbial community, but not in its diversity. The Deinococcus/Thermus phylum, especially the Meiothermus genus, was in large part responsible for the differences between the communities, and was positively associated with the presence of copper and other heavy metals in the environmental samples. Other important parameters that influenced the bacterial diversity and composition were the elements potassium, sodium, nickel, and zinc, as well as pH. The findings contribute to the understanding of bacterial diversity in soils impacted by neutral mine drainage, and demonstrate that heavy metals play an important role in shaping the microbial population in mine environments.

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In this work the archaea and eubacteria community of a hypersaline produced water from the Campos Basin that had been transported and discharged to an onshore storage facility was evaluated by 16S recombinant RNA (rRNA) gene sequence analysis. The produced water had a hypersaline salt content of 10 (w/v), had a carbon oxygen demand (COD) of 4,300 mg/l and contains phenol and other aromatic compounds. The high salt and COD content and the presence of toxic phenolic compounds present a problem for conventional discharge to open seawater. In previous studies, we demonstrated that the COD and phenolic content could be largely removed under aerobic conditions, without dilution, by either addition of phenol degrading Haloarchaea or the addition of nutrients alone. In this study our goal was to characterize the microbial community to gain further insight into the persistence of reservoir community members in the produced water and the potential for bioremediation of COD and toxic contaminants. Members of the archaea community were consistent with previously identified communities from mesothermic reservoirs. All identified archaea were located within the phylum Euryarchaeota, with 98 % being identified as methanogens while 2 % could not be affiliated with any known genus. Of the identified archaea, 37 % were identified as members of the strictly carbon-dioxide-reducing genus Methanoplanus and 59 % as members of the acetoclastic genus Methanosaeta. No Haloarchaea were detected, consistent with the need to add these organisms for COD and aromatic removal. Marinobacter and Halomonas dominated the eubacterial community. The presence of these genera is consistent with the ability to stimulate COD and aromatic removal with nutrient addition. In addition, anaerobic members of the phyla Thermotogae, Firmicutes, and unclassified eubacteria were identified and may represent reservoir organisms associated with the conversion hydrocarbons to methane.

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Ant foraging on foliage can substantially affect how phytophagous insects use host plants and represents a high predation risk for caterpillars, which are important folivores. Ant-plant-herbivore interactions are especially pervasive in cerrado savanna due to continuous ant visitation to liquid food sources on foliage (extrafloral nectaries, insect honeydew). While searching for liquid rewards on plants, aggressive ants frequently attack or kill insect herbivores, decreasing their numbers. Because ants vary in diet and aggressiveness, their effect on herbivores also varies. Additionally, the differential occurrence of ant attractants (plant and insect exudates) on foliage produces variable levels of ant foraging within local floras and among localities. Here, we investigate how variation of ant communities and of traits among host plant species (presence or absence of ant attractants) can change the effect of carnivores (predatory ants) on herbivore communities (caterpillars) in a cerrado savanna landscape. We sampled caterpillars and foliage-foraging ants in four cerrado localities (70-460 km apart). We found that: (i) caterpillar infestation was negatively related with ant visitation to plants; (ii) this relationship depended on local ant abundance and species composition, and on local preference by ants for plants with liquid attractants; (iii) this was not related to local plant richness or plant size; (iv) the relationship between the presence of ant attractants and caterpillar abundance varied among sites from negative to neutral; and (v) caterpillars feeding on plants with ant attractants are more resistant to ant predation than those feeding on plants lacking attractants. Liquid food on foliage mediates host plant quality for lepidopterans by promoting generalized ant-caterpillar antagonism. Our study in cerrado shows that the negative effects of generalist predatory ants on herbivores are detectable at a community level, affecting patterns of abundance and host plant use by lepidopterans. The magnitude of ant-induced effects on caterpillar occurrence across the cerrado landscape may depend on how ants use plants locally and how they respond to liquid food on plants at different habitats. This study enhances the relevance of plant-ant and ant-herbivore interactions in cerrado and highlights the importance of a tritrophic perspective in this ant-rich environment.

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The objectives were to identify factors associated with decreased life satisfaction in community-dwelling elderly and describe such factors according to gender and age bracket. The study interviewed 2,472 elderly individuals 65 years or older without cognitive deficits suggestive of dementia, in probabilistic samples from seven Brazilian cities. All measures were self-reported except for functional performance, indicated by handgrip and gait speed. Women had more chronic diseases, worse functional performance, and greater social involvement when compared to men. The oldest participants showed worse functional performance and less social involvement when compared to the youngest. Low satisfaction was associated with three or more diseases, memory problems, low social involvement, low handgrip strength, and urinary incontinence. The authors conclude that health, functional performance, and social involvement interact with well-being, so interventions targeting these areas can favor quality of life for the elderly.

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We analyzed the structure of the understory community in the Atlantic Forest sensu lato, for which phytosociological descriptions of the understory are lacking. We delineated 50 plots of 10 × 20 m each at four sites within an Araucaria forest (a subtype of Atlantic Forest), located in the municipalities of Bananal, Campos do Jordão, Itaberá and Barra do Chapéu, all of which are in the state of São Paulo, Brazil. To sample the resident species of the understory, we randomly selected five 1 × 1 m subplots within each plot, resulting in a total sampling area of 250 m² at each site. We identified differences among the locations, mostly due to proportional differences in growth forms, in terms of species richness and the importance values within the community. Factors potentially influencing the understory structure include macroclimatic and microclimatic conditions, as well as forest fragmentation, the abundance of deciduous trees in the canopy, the surrounding vegetation and geographic location.

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OBJECTIVE: This study aimed to compare skeletal, dentoalveolar and soft tissue characteristics in white and black Brazilian subjects presenting normal occlusions. MATERIAL AND METHODS: The sample comprised the lateral cephalograms of 106 untreated Brazilian subjects with normal occlusion, divided into two groups: Group 1- 50 white subjects (25 of each gender), at a mean age of 13.17 years (standard deviation 1.07); and Group 2- 56 black subjects (28 of each gender), at a mean age of 13.24 years (standard deviation 0.56). Variables studied were obtained from several cephalometric analyses. Independent t tests were used for intergroup comparison and to determine sexual dimorphism. RESULTS: black subjects presented a more protruded maxilla and mandible, a smaller chin prominence and a greater maxillomandibular discrepancy than white subjects. Blacks presented a more horizontal craniofacial growth pattern than whites. Maxillary and mandibular incisors presented more protruded and proclined in black subjects. The nasolabial angle was larger in whites. Upper and lower lips were more protruded in blacks than in whites. CONCLUSIONS: The present study found a bimaxillary skeletal, dentoalveolar and soft tissue protrusion in black Brazilian subjects compared to white Brazilian subjects, both groups with normal occlusion. Upper and lower lips showed to be more protruded in blacks, but lip thickness was similar in both groups.

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The oil obtained from Brazilian roasted coffee by supercritical CO2 extraction shows considerable aromatic properties, mainly composed by five aromatic compounds, 2-methylpyrazine; 2-furfurylalcohol, 2,5-dimethylpyrazine; γ-butyrolactone and 2-furfurylacetate. Sensory analyses were used to verify the influence of a mixture of these important classes of aromatic coffee compounds (pyrazines, furans and lactones) and of the roasted coffee aromatic oil on the coffee aroma and flavour of black instant freeze and spray-dried coffee beverages. In the acceptance evaluation of the aroma, the samples prepared with freeze-dried instant coffee without the mixture of volatile compounds (sample 4) were not significantly different from the freeze-dried instant coffee in which the aromatic coffee oil was added (sample 5) and from the sample prepared with freeze-dried coffee in which the mixture of the five volatile was added (sample 3), coincidentally from the same drying process. Therefore, sample (3) did not differ from samples prepared with spray dried instant coffee without (sample 1) and to which (sample 2) the mixture of volatile was added. Therefore, with respect to this attribute, the addition of this mixture did not interfere in this drink acceptance. Taking into consideration the flavor, samples prepared with freeze-dried instant coffee in which the aromatic coffee oil was added (5) and the samples with (3) and without (4) the mixture of the five volatile was added did not differ significantly, however sample (4) did not differ from samples (1) and (2). Regarding this attribute, the addition of the aromatic oil of roasted coffee or a mixture of volatile in samples of freeze-dried instant coffee had a better acceptance than those dried by spray dryer (1) and (2). Thus, the enrichment of drinks with the aromatic oil of roasted coffee, or even with the mixture of the five components did not influence the consumer acceptance with respect to the aroma, but exerts influence with respect to flavour.

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RATIONALE: Benign focal seizures of adolescence (BFSA) described by Loiseau et al in 1972, is considered a rare entity, but maybe underdiagnosed. Although mild neuropsychological deficits have been reported in patients with benign epilepsies of childhood, these evaluations have not so far been described in BFSA. The aim of this study is to evaluate neuropsychological functions in BFSA with new onset seizures (<12 months). METHODS: Eight patients with BFSA (according to Loiseau et al, 1972, focal or secondarily tonic clonic generalized seizures between the ages of 10-18 yrs., normal neurologic examination, normal EEG or with mild focal abnormalities) initiated in the last 12 months were studied between July 2008 to May 2009. They were referred from the Pediatric Emergency Section of the Hospital Universitário of the University of Sao Paulo, a secondary care regionalized facility located in a district of middle-low income in Sao Paulo city, Brazil. The study was approved by the Ethics Committee of the Institution. All patients performed neurological, EEG, brain CT and neuropsychological evaluation which consisted of Raven's Special Progressive Matrices - General and Special Scale (according to different ages), Wechsler Children Intelligence Scale-WISC III with ACID Profile, Trail Making Test A/B, Stroop Test, Bender Visuo-Motor Test, Rey Complex Figure, Rey Auditory Verbal Learning Test-RAVLT, Boston Naming Test, Fluency Verbal for phonological and also conceptual patterns - FAS/Animals and Hooper Visual Organization Test. For academic achievement, we used a Brazilian test for named "Teste do Desempenho Escolar", which evaluates abilities to read, write and calculate according to school grade. RESULTS: There were 2 boys and 6 girls, with ages ranging from 10 yrs. 9 m to 14 yrs. 3 m. Most (7/8) of the patients presented one to two seizures and only three of them received antiepileptic drugs (AEDs). Six had mild EEG focal abnormalities and all had normal brain CT. All were literate, attended regular public schools and scored in a median range for IQ, and seven showed discrete higher scores for the verbal subtests. There were low scores for attention in different modalities in six patients, mainly in alternated attention as well as inhibitory subtests (Stroop test and Trail Making Test part B). Four of the latter cases who showed impairment both in alternated and inhibitory attention were not taking AEDs. Visual memory was impaired in five patients (Rey Complex Figure). Executive functions analysis showed deficits in working memory in five, mostly observed in Digits Indirect Order and Arithmetic tests (WISC III). Reading and writing skills were below the expected average for school grade in six patients according to the achievement scholar performance test utilized. One patient of this series who had the best scores in all tests was taking phenobarbital. CONCLUSIONS: Neuropsychological imbalance between normal IQ and mild dysfunctions such as in attention domain and in some executive abilities like working memory and planning, as well as difficulties in visual memory and in reading and writing, were described in this group of patients with BFSA from community. This may reflect mild higher level neurological dysfunctions in adolescence idiopathic focal seizures probably caused by an underlying dysmaturative epileptogenic process. Although academic problems often have multiple causes, a specific educational approach may be necessary in these adolescents, in order to improve their scholastic achievements, helping in this way, to decrease the stigma associated to epileptic seizures in the community.

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Secondary forests and exotic tree plantations are expanding across tropical landscapes. However, our current understanding of the value of these human-dominated forest landscapes for invertebrate biodiversity conservation is still very poor. In this paper, we use the leaf-litter ant fauna to assess invertebrate diversity in one commercially managed Eucalyptus plantation (four years old), two abandoned plantations of different regeneration ages (16 and 31 years), and one neighboring secondary Atlantic Forest in Southeastern Brazil. There was a clear gradient in species richness from the secondary forest to the managed Eucalyptus plantation; richness and diversity peaked in secondary forest and in the older regenerating Eucalyptus plantation. Significantly more species were recorded in secondary forest samples than in Eucalyptus plantations, but Eucalyptus plantations had a similar level of richness. Furthermore, a non-metric multidimensional scaling analysis revealed clear differences in species composition between the younger managed Eucalyptus plantation (understory absent) and habitats with sub-developed or developed understory. Eucalyptus plantations were characterized by an assemblage of widespread, generalist species very different from those known to occur in core forest habitats of southeastern Brazil. Our results indicate that while older regenerating Eucalyptus plantations can provide habitat to facilitate the persistence of generalist ant species, it is unlikely to conserve most of the primary forest species, such as specialized predators, Dacetini predators, and nomadic species.