987 resultados para Age diversity
Resumo:
The complex interactions among endangered ecosystems, landowners` interests, and different models of land tenure and use, constitute an important series of challenges for those seeking to maintain and restore biodiversity and augment the flow of ecosystem services. Over the past 10 years, we have developed a data-based approach to address these challenges and to achieve medium and large-scale ecological restoration of riparian areas on private lands in the state of Sao Paulo, southeastern Brazil. Given varying motivations for ecological restoration, the location of riparian areas within landholdings, environmental zoning of different riparian areas, and best-practice restoration methods were developed for each situation. A total of 32 ongoing projects, covering 527,982 ha, were evaluated in large sugarcane farms and small mixed farms, and six different restoration techniques have been developed to help upscale the effort. Small mixed farms had higher portions of land requiring protection as riparian areas (13.3%), and lower forest cover of riparian areas (18.3%), than large sugarcane farms (10.0% and 36.9%, respectively for riparian areas and forest cover values). In both types of farms, forest fragments required some degree of restoration. Historical anthropogenic degradation has compromised forest ecosystem structure and functioning, despite their high-diversity of native tree and shrub species. Notably, land use patterns in riparian areas differed markedly. Large sugarcane farms had higher portions of riparian areas occupied by highly mechanized agriculture, abandoned fields, and anthropogenic wet fields created by siltation in water courses. In contrast, in small mixed crop farms, low or non-mechanized agriculture and pasturelands were predominant. Despite these differences, plantations of native tree species covering the entire area was by far the main restoration method needed both by large sugarcane farms (76.0%) and small mixed farms (92.4%), in view of the low resilience of target sites, reduced forest cover, and high fragmentation, all of which limit the potential for autogenic restoration. We propose that plantations should be carried out with a high-diversity of native species in order to create biologically viable restored forests, and to assist long-term biodiversity persistence at the landscape scale. Finally, we propose strategies to integrate the political, socio-economic and methodological aspects needed to upscale restoration efforts in tropical forest regions throughout Latin America and elsewhere. (C) 2010 Elsevier BA/. All rights reserved.
Resumo:
The diversity and beneficial characteristics of endophytic microorganisms have been studied in several host plants. However, information regal-ding naturally, occurring seed-associated endophytes and vertical transmission among different life-history stages of hosts is limited. Endophytic bacteria were isolated from seeds and seedlings of 10 Eucalyptus species and two hybrids. The results showed that endophytic bacteria, Such as Bacillus, Enterococcus, Paenibacillus and Methylobacterium, are vertically transferred from seeds to seedlings. In addition, the endophytic bacterium Pantoea agglomerans was tagged with the gfp gene, inoculated into seeds and further reisolated from seedlings. These results suggested it novel approach to change the profile of the plants, where the bacterium is a delivery vehicle for desired traits. This is the first report of an endophytic bacterial community residing in Eucalyptus seeds and the transmission of these bacteria from seeds to seedlings. The bacterial species reported ill this work have been described as providing benefits to host plants. Therefore, we Suggest that endophytic bacteria can be transmitted vertically from seeds to seedlings, assuring the support of the bacterial community in the host plant.
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Background: Cobalamin (Cbl) and folate deficiencies and gene polymorphism of key enzymes or carriers can impair homocysteine metabolism and may change the serum values of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). We investigated the nutritional and genetic determinants for total homocysteine (tHcy), methylmalonic acid (MMA) and SAM/SAH in healthy Brazilian childbearing-age women. Methods: Serum concentrations of Cbl, folate, red blood cell folate, ferritin, tHcy, MMA, SAM, SAH and other metabolites were measured in 102 healthy unrelated women. The genotypes for MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G, TC2 C776G, TC2 A67G and RFCI A80G gene polymorphisms were identified by PCR-RFLP. Results: Serum folate and Cbl were inversely correlated with tHcy and serum MMA, respectively. Cbl deficiency was associated with increased MMA and reduced alpha-aminobutyrate, serine and N-methylglycine concentrations. No variable was associated with SAM/SAH ratio. In addition, gene polymorphisms were not selected as determinants for tHcy, MMA and SAM/SAH ratio. Iron, Cbl and folate deficiencies were found respectively in 30.4%, 22.5% and 2.0% of individuals studied. Conclusions: There was a high frequency of Cbl and iron deficiency in this group of childbearing-age women. Serum folate and Cbl were the determinants of serum tHcy and MMA concentration, respectively. (c) 2007 Elsevier B.V. All rights reserved.
Resumo:
The palladium catalyzed cross-coupling reaction of phenyltrifluoroborate with a chemoenzymatically derived bromoazidoconduritol, combined with 1,3-dipolar cycloaddition, with a variety of alkynes is described. Fourteen new compounds were synthesized in moderate to good yields. The click chemistry reaction can be effected by using sodium ascorbate and CuSO(4) center dot 5H(2)O as catalyst in toluene-H(2)O at room temperature.
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The Kluyveromyces marxianus strains CBS 6556, CBS 397 and CBS 712(T) were cultivated on a defined medium with either glucose, lactose or sucrose as the sole carbon source, at 30 and 37A degrees C. The aim of this work was to evaluate the diversity within this species, in terms of the macroscopic physiology. The main properties evaluated were: intensity of the Crabtree effect, specific growth rate, biomass yield on substrate, metabolite excretion and protein secretion capacity, inferred by measuring extracellular inulinase activity. The strain Kluyveromyces lactis CBS 2359 was evaluated in parallel, since it is the best described Kluyveromyces yeast and thus can be used as a control for the experimental setup. K. marxianus CBS 6556 presented the highest specific growth rate (0.70 h(-1)) and the highest specific inulinase activity (1.65 U mg(-1) dry cell weight) among all strains investigated, when grown at 37A degrees C with sucrose as the sole carbon source. The lowest metabolite formation and highest biomass yield on substrate (0.59 g dry cell weight g sucrose(-1)) was achieved by K. marxianus CBS 712(T) at 37A degrees C. Taken together, the results show a systematic comparison of carbon and energy metabolism among three of the best known K. marxianus strains, in parallel to K. lactis CBS 2359.
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Chemical compounds on the cuticle are a rich source of information used during interactions among social insects. Despite the multitude of studies on these substances and their function in ants, wasps, and honeybees, little is known about this subject in stingless bees (Hymenoptera: Apidae, Meliponini). We studied the chemical composition of the cuticle of the stingless bee, Frieseomelitta varia, by gas chromatography-mass spectrometry (GC-MS), to investigate potential chemical variation among castes, gender, age, and reproductive status. We found differences in the cuticular hydrocarbon composition among workers, males, and queens, recording both qualitative and quantitative differences among individuals of different ages and gender. The cuticle of physogastric queens presented a chemical profile that was distinct from all other groups in the analysis, with high relative abundances of alkenes and alkadienes with 27, 29, and 31 carbon atoms. We discuss the possibility that these compounds signal a queen`s presence to the colony, thereby initiating all vital worker-queen interactions.
Resumo:
Objective: To describe an outbreak of imipenem-resistant metallo-beta-lactamase-producing Pseudomonas aeruginosa, enzyme type bla, by horizontal transmission in patients admitted to a mixed adult ICU. Methods: A case-control study was carried out, including 47 patients (cases) and 122 patients (control) admitted to the mixed ICU of a university hospital in Minas Gerais. Brazil from November 2003 to July 2005. The infection site, risk factors, mortality, antibiotic susceptibility, metallo-beta-lactamase (MBL) production, enzyme type, and clonal diversity were analyzed, Results: A temporal/spatial relationship was detected in most patients (94%), overall mortality was 55.3%, and pneumonia was the predominant infection (85%). The majority of isolates (95%) were resistant to imipenem and other antibiotics, except for polymyxin, and showed MBL production (76.7%). Only bla SPM-1 (33%) was identified in the 15 specimens analyzed. In addition, 4 clones were identified, with a predominance of clone A (61.5%) and B (23.1%). On multivariate analysis, advanced age, mechanical ventilation, tracheostomy, and previous imipenem use were significant risk factors for imipenem-resistant P. aeruginosa infection. Conclusions: Clonal dissemination of MBL-producing P. aeruginosa strains with a spatial/temporal relationship disclosed problems in the practice of hospital infection control, low adherence to hand hygiene, and empirical antibiotic use. (C) 2008 Elsevier Espana, S.L. All rights reserved.
Resumo:
Age is a critical determinant of an adult female mosquito's ability to transmit a range of human pathogens. Despite its central importance, relatively few methods exist with which to accurately determine chronological age of field-caught mosquitoes. This fact is a major constraint on our ability to fully understand the relative importance of vector longevity to disease transmission in different ecological contexts. It also limits our ability to evaluate novel disease control strategies that specifically target mosquito longevity. We report the development of a transcriptional profiling approach to determine age of adult female Aedes aegypti under field conditions. We demonstrate that this approach surpasses current cuticular hydrocarbon methods for both accuracy of predicted age as well as the upper limits at which age can be reliably predicted. The method is based on genes that display age-dependent expression in a range of dipteran insects and, as such, is likely to be broadly applicable to other disease vectors.
Resumo:
Age is a critical determinant of the ability of most arthropod vectors to transmit a range of human pathogens. This is due to the fact that most pathogens require a period of extrinsic incubation in the arthropod host before pathogen transmission can occur. This developmental period for the pathogen often comprises a significant proportion of the expected lifespan of the vector. As such, only a small proportion of the population that is oldest contributes to pathogen transmission. Given this, strategies that target vector age would be expected to obtain the most significant reductions in the capacity of a vector population to transmit disease. The recent identification of biological agents that shorten vector lifespan, such as Wolbachia, entomopathogenic fungi and densoviruses, offer new tools for the control of vector-borne diseases. Evaluation of the efficacy of these strategies under field conditions will be possible due to recent advances in insect age-grading techniques. Implementation of all of these strategies will require extensive field evaluation and consideration of the selective pressures that reductions in vector longevity may induce on both vector and pathogen.
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The Asian tiger mosquito, Aedes albopictus (Skuse), is a known vector of dengue in South America and Southeast Asia. It is naturally superinfected with two strains of Wolbachia endosymbiont that are able to induce cytoplasmic incompatibility (CI). In this paper, we report the strength of CI expression in crosses involving field-caught males. CI expression was found to be very strong in all crosses between field males and laboratory-reared uninfected or wAlbA infected young females. In addition, crossing experiments with laboratory colonies showed that aged super- infected males could express strong CI when mated with young uninfected or wAlbA infected females. These results provide additional evidence that the CI properties of Wolbachia infecting Aedes albopictus are well suited for applied strategies that seek to utilise Wolbachia for host population modification.
Resumo:
This article provides a review of recent developments in two topical areas of research in contemporary organizational behavior: diversity and emotions. In the section called “Diversity,”we trace the history of diversity research, explore the definitions and paradigms used in treatments of diversity, and signal new areas of interest. We conclude that organizational behavior in the 21st century is evolving to embrace a more eclectic and holistic view of humans at work. In the section called “Emotions,” we turn our attention to recent developments in the study of emotions in organizations. We identify four major topics: mood theory, emotional labor, affective events theory (AET), and emotional intelligence, and argue that developments in the four domains have significant implications for organizational research, and the progression of the study of organizational behavior. As with the study of diversity, the topic of emotions in the workplace is shaping up as one of the principal areas of development in management thought and practice for the next decade. Finally, we discuss in our conclusion how these two areas are being conceptually integrated, and the implications for management scholarship and research in the contemporary world.
Letters of the Great Kings of the Ancient Near East: The Royal Correspondence of the Late Bronze Age