433 research outputs found

    Body Mass Index and Cognitive Decline in Mild Cognitive Impairment

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    This is the author's accepted manuscript.Objective To examine the relationship between body mass index (BMI) and cognitive decline in subjects diagnosed with mild cognitive impairment (MCI). Methods Neuropsychologic and clinical evaluations were conducted at baseline, 6-months, and 1-year on 286 MCI subjects enrolled in the Alzheimer’s Disease Neuroimaging Initiative. A global cognitive composite score was derived (mean Z-score) from performance on 9 neuropsychologic subtests. Height and weight were assessed at baseline and used to calculate BMI. Generalized estimating equations (linear and logistic) assessed the relationships of baseline BMI with cognitive outcomes, clinician judgment of “clinically significant decline” over 1-year, and diagnostic progression from MCI to Alzheimer disease. Results Lower baseline BMI was associated with significant declines in cognitive performance in individuals with MCI over 1 year (Mini-Mental State Examination, Alzheimer Disease Assessment Scale-Cognitive subscale, and a global cognitive composite; all P<0.05). We observed a significant protective effect of baseline BMI in reducing the risk of a clinically significant decline in Alzheimer Disease Assessment Scale-Cognitive subscale and mini-mental state examination (P<0.05). No association was found between BMI and changes in the clinical dementia rating sum of boxes or conversion to Alzheimer disease. Conclusions Lower baseline BMI is associated with more rapid cognitive decline in MCI. This relationship suggests either body composition may influence the rate of cognitive decline in MCI or factors related to MCI influence body composition

    Age and structure of the Shyok Suture in the Ladakh region of Northwestern India: Implications for slip on the Karakoram Fault System

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    A precise age for the collision of the Kohistan-Ladakh block with Eurasia along the Shyok suture zone (SSZ) is one key to understanding the accretionary history of Tibet and the tectonics of Eurasia during the India-Eurasia collision. Knowing the age of the SSZ also allows the suture to be used as a piercing line for calculating total offset along the Karakoram Fault, which effectively represents the SE border of the Tibetan Plateau and has played a major role in plateau evolution. We present a combined structural, geochemical, and geochronologic study of the SSZ as it is exposed in the Nubra region of India to test two competing hypotheses: that the SSZ is of Late Cretaceous or, alternatively, of Eocene age. Coarse-continental strata of the Saltoro Molasse, mapped in this area, contain detrital zircon populations suggestive of derivation from Eurasia despite the fact that the molasse itself is deposited unconformably onto Kohistan-Ladakh rocks, indicating that the molasse is postcollisional. The youngest population of detrital zircons in these rocks (approximately 92 Ma) and a U/Pb zircon date for a dike that cuts basal molasse outcrops (approximately 85 Ma) imply that deposition of the succession began in the Late Cretaceous. This establishes a minimum age for the SSZ and rules out the possibility of an Eocene collision between Kohistan-Ladakh and Eurasia. Our results support correlation of the SSZ with the Bangong suture zone in Tibet, which implies a total offset across the Karakoram Fault of approximately 130–190 km

    The immune cell infiltrate populating meningiomas is composed of mature, antigen-experienced T and B cells

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    BACKGROUND: Meningiomas often harbor an immune cell infiltrate that can include substantial numbers of T and B cells. However, their phenotype and characteristics remain undefined. To gain a deeper understanding of the T and B cell repertoire in this tumor, we characterized the immune infiltrate of 28 resected meningiomas representing all grades. METHODS: Immunohistochemistry was used to grossly characterize and enumerate infiltrating lymphocytes. A molecular analysis of the immunoglobulin variable region of tumor-infiltrating B cells was used to characterize their antigen experience. Flow cytometry of fresh tissue homogenate and paired peripheral blood lymphocytes was used to identify T cell phenotypes and characterize the T cell repertoire. RESULTS: A conspicuous B and T cell infiltrate, primarily clustered in perivascular spaces, was present in the microenvironment of most tumors examined. Characterization of 294 tumor-infiltrating B cells revealed clear evidence of antigen experience, in that the cardinal features of an antigen-driven B cell response were present. Meningiomas harbored populations of antigen-experienced CD4+ and CD8+ memory/effector T cells, regulatory T cells, and T cells expressing the immune checkpoint molecules PD-1 and Tim-3, indicative of exhaustion. All of these phenotypes were considerably enriched relative to their frequency in the circulation. The T cell repertoire in the tumor microenvironment included populations that were not reflected in paired peripheral blood. CONCLUSION: The tumor microenvironment of meningiomas often includes postgerminal center B cell populations. These tumors invariably include a selected, antigen-experienced, effector T cell population enriched by those that express markers of an exhausted phenotype

    Community management does not equate to participation: fostering community participation in rural water supplies

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    Community management has remained the dominant paradigm for managing rural water supplies in sub-Saharan Africa. There is a widespread perception that community participation principles are inherently embedded in the community management model. In this paper, we analyze how an international nongovernmental organization engages rural communities in their rural water projects, and the ways in which community members are able to participate in the management and governance of their water supplies. Qualitative data were collected in 18 study communities – six each in Ghana, Kenya, and Zambia – through interviews, focus group discussions, and participatory mapping with community and water committee members. We argue that community management does not inherently lead to broader community participation, but rather that fostering community participation requires intentionality. We recommend implementers use collaborative planning processes and explicitly engage with intra-community diversity and inequalities in order to facilitate the opportunity for all community members to meaningfully participate in decision-making. Collaborative planning with diverse groups will also allow community members to realize their rights to transparency and accountability once community management structures are in place

    Soil seed bank of the invasive Robinia pseudoacacia in planted Pinus nigra stands

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    Pinus nigra and Robinia pseudoacacia are exotic trees used for afforestation in Hungary. Pinus nigra was non-invasive, however R. pseudoacacia escaped from cultivation and invaded several vegetation types including pine plantations. It has recently been planned to cut P. nigra plantations and replace them by native tree stands, especially in nature reserves. The scattered presence of R. pseudoacacia specimens in pine stands might place constraints on planned tree replacement because of their vegetative resprouting and recolonization from an established seed bank. The aim of this study was to investigate the soil seed bank under the canopy of solitary R. pseudoacacia specimens found in P. nigra plantations. Altogether 250 soil samples were collected from the 0–6 and 6–12 cm soil layers under solitary Robinia trees of varying ages (with basal areas between 62.4 and 1089.3 cm2). Seeds were separated by sieving then scarified and germinated. Seed bank density ranged between 640 and 2285 seedsm–2 with an average distribution of 82.7% and 17.3% in the upper and lower soil layer, respectively. Total density of the seed bank and also the seed bank ratio of the lower soil layer increased with tree age. The accumulated seed bank of R. pseudoacacia should be considered in the careful planning of tree replacement operations in Pinus nigra stands

    Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L

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    [EN] Rhamnus ludovici-salvatoris, endemic to the Gymnesian Islands, coexists with the related and widespread R. alaternus in Mallorca and Menorca. In both species, the population genetic structure using RAPD, and flowering during a 3-year period to check for possible phenological barriers, were analyzed. Rhamnus ludovici-salvatoris showed lower genetic diversity and stronger population structure than R. alaternus, the Cabrera population being less diverse and the most differentiated. Rhamnus ludovici-salvatoris flowered one month later, although flowering of both species coincided sporadically. These congeners seem to have diverged through isolation by time and differentiation in habitat. The population genetic structure of R. ludovici-salvatoris could mainly be due to the existence of small populations on the one hand, and a gene flow caused by rare hybridization events on the other, which may also explain the presence of morphologically intermediate individuals in Menorca. The conservation of R. ludovici-salvatoris populations may include population reinforcements and other in situ interventions.Ferriol Molina, M.; Llorens García, L.; Gil, L.; Boira Tortajada, H. (2009). Influence of phenological barriers and habitat differentiation on the population genetic structure of the balearic endemic Rhamnus ludovici-salvatoris Chodat and R. alaternus L. Plant Systematics and Evolution. 277(1-2):105-116. doi:10.1007/s00606-008-0110-3S1051162771-2Affre L, Thompson JD, Debussche M (1997) Genetic structure of continental and island populations of the Mediterranean endemic Cyclamen balearicum (Primulaceae). Amer J Bot 84(4): 437–451BOIB (2005) Decreto 75/2005. BOIB 106: 29–32Bolmgren K, Oxelman B (2004) Generic limits in Rhamnus L. s.l. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies. Taxon 53(2):383–390Bolòs O, Molinier R (1958) Recherches phytosociologiques dans l’île de Majorque. Collectanea Botanica 34:699–865Cardona MA (1979) Consideracions sobre l’endemisme i l’origen de la flora de las Illes Balears. Butlletí del Institut Catalá de Historia Natural 44 (Sec. Bot. 3):7–15Cardona MA, Contandriopoulos J (1979) Endemism and evolution in the islands of the Western Mediterranean. In: Bramwell D (ed) Plants and islands. Academic Press, London, pp 133–169Chodat L (1924) Contributions à la Géo-Botanique de Majorque. PhD Thesis, Université de Genève—Institut de Botanique, SwitzerlandCollins D, Mill RR, Moller M (2003) Species separation of Taxus baccata, T. canadensis, and T. cuspidata (Taxaceae) and origins of their reputed hybrids inferred from RAPD and cpDNA data. Amer J Bot 90(2):175–182Cronk QCB (1997) Islands: stability, diversity, conservation. Biodivers Conserv 6(3):477–493Doyle JJ, Doyle JL (1990) Isolation of plant DNA from fresh tissue. Focus 12:13–15Ducarme V, Wesselingh RA (2005) Detecting hybridization in mixed populations of Rhinanthus minor and Rhinanthus angustifolius. Folia Geobot 40(2/3):151–161Englishloeb GM, Karban R (1992) Consequences of variation in flowering phenology for seed head herbivory and reproductive success in Erigeron glaucus (Compositae). Oecologia 89:588–595Gautier F, Caluzon G, Suk JP, Violanti D (1994) Age et durée de la crise de salinité Messinienne. Comptes Rendus de l’Académie des Sciences de Paris 318:1103–1109Gerard PR, Fernandez-Manjarres JF, Frascaria-Lacoste N (2006) Temporal cline in a hybrid zone population between Fraxinus excelsior L. and Fraxinus angustifolia Vahl. Molec Ecol 15:3655–3667Gil L, Llorens L, Tébar FJ, Costa M (1995) La vegetación de la isla de Cabrera. In: Guía de la excursión geobotánica de las XV Jornadas de Fitosociología. Datos sobre la vegetación de Cabrera. Palma de Mallorca: Universitat de les Illes Balears, pp 51–77Gulías J, Flexas J, Abadía A, Medrano H (2002) Photosynthetic responses to water deficit in six Mediterranean sclerophyll species: possible factors explaining the declining distribution of Rhamnus ludovici-salvatoris, and endemic Balearic species. Tree Physiol 22:687–697Gulías J, Traveset A, Riera N, Mus M (2004) Critical stages in the recruitment process of Rhamnus alaternus L. Ann Bot 93:723–731Gustafsson S, Sjögren-Gulve P (2002) Genetic diversity in the rare orchid, Gymnadenia odoratissima and a comparison with the more common congener, G. conopsea. Conserv Genet 3:225–234Gustafsson S (2003) Population genetic analyses in the orchid genus Gymnadenia—a conservation genetic perspective. PhD Thesis, Uppsala University, SwedenGustafsson S, Lönn M (2003) Genetic differentiation and habitat preference of flowering-time variants within Gymnadenia conopsea. Heredity 91:284–292Harris W (1996) Genecological aspects of flowering patterns of populations of Kunzea ericoides and K. sinclairii (Myrtaceae). New Zealand J Bot 34:333–354Hendry AP, Dray T (2005) Population structure attributable to reproductive time: isolation by time and adaptation by time. Molec Ecol 14:901–916Hosokawa K, Minami M, Kawahara K, Nakamura I, Shibata T (2000) Discrimination among three species of medicinal Scutellaria plants using RAPD markers. Pl Med 66:270–272Huang Z, Liu L, Zhou T, Ju B (2005) Effects of environmental factors on the population genetic structure in chukar partridge (Alectoris chukar). J Arid Environ 62:427–434Juan A, Crespo MB, Cowan RS, Lexer C, Fay F (2004) Patterns of variability and gene flow in Medicago citrina, an endangered endemic of islands in the western Mediterranean, as revealed by amplified fragment length polymorphism (AFLP). Molec Ecol 13:2679–2690Krijgsman W, Hilgen FJ, Raffi I, Sierro FJ, Wilson DS (1999) Chronology, causes and progression of the Messinian salinity crisis. Nature 400:652–655Lamont BB, He T, Enright NJ, Krauss SL, Miller BP (2003) Anthropogenic disturbance promotes hybridization between Banksia species by altering their biology. J Evol Biol 16:551–557Lennartsson T (1997) Seasonal differentiation—a conservative reproductive barrier in two grassland Gentianella (Gentianaceae) species. Pl Syst Evol 208:45–69Martinez-Solis I, Iranzo J, Estrelles E, Ibars AM (1993) Leaf domatia in the section Alaternus (Miller) DC. of the genus Rhamnus (Rhamnaceae). Bot J Linn Soc 112:311–318McIntosh ME (2002) Flowering phenology and reproductive output in two sister species of Ferocactus (Cactaceae). Pl Ecol 159:1–13Nei M (1973) Analysis of gene diversity in subdivided populations. Proc Natl Acad Sci USA 70:3321–3323Nei M (1978) Estimation of average heterozigosity and genetic distance from a small number of individuals. Genetics 89:583–590Nei M, Li W (1979) Mathematical model for studying genetic variation in terms of restriction endonucleases. Proc Natl Acad Sci USA 79:5269–5273Nybom H, Bartish IV (2000) Effects of life history traits and sampling strategies on genetic diversity estimates obtained with RAPD markers in plants. Perspect Pl Ecol Evol Syst 3(2):93–114Oostermeijer JGB, Luijten SH, Ellis-Adam AC, den Nijs JCM (2002) Future prospects for the rare, late-flowering Gentianella germanica and Gentianopsis ciliata in Dutch nutrient-poor calcareous grasslands. Biol Conserv 104:339–350Pease CM, Lande R, Bull JJ (1989) A model of population growth, dispersal and evolution in a changing environment. Ecology 70(6):1657–1664Perron M, Gordon AG, Bousquet J (1995) Species-specific RAPD fingerprints for the closely related Picea mariana and P. rubens. Theor Appl Genet 91:142–149Pierce S, Ceriani RM, Villa M, Cerabolini B (2006) Quantifying relative extinction risks and targeting intervention for the orchid flora of a natural park in the European prealps. Conserv Biol 20(6):1804–1810Richardson JE, Fay MF, Cronk QCB, Bowman D, Chase MW (2000) A phylogenetic analysis of Rhamnaceae using rbcL and trnL-F plastid DNA sequences. Amer J Bot 87(9):1309–1324Roselló JA, Sáez L (2000) Index Balearicum: an annotated check-list of the vascular plants described from the Balearic Islands. Collect Bot 25(1):3–203Roselló JA, Cebrián MC, Mayol M (2002) Testing taxonomic and biogeographical relationships in a narrow mediterranean endemic complex (Hippocrepis balearica) using RAPD markers. Ann Bot 89:321–327Sales E, Nebauer SG, Mus M, Segura J (2001) Population genetic study in the Balearic plant species Digitalis minor (Scrophulariaceae) using RAPD markers. Amer J Bot 88(10):1750–1759Sherwin WB, Moritz C (2000) Managing and monitoring genetic erosion. In: Young AG, Clarke GM (eds) Genetics, demography and viability of fragmented populations. Cambridge University Press, Cambridge, pp 9–34Sneath PHA, Sokal RR (1973) Numerical taxonomy. Freeman and Co., San FranciscoTraveset A, Gulías J, Riera N, Mus M (2003) Transition probabilities from pollination to establishment in a rare dioecious shrub species (Rhamnus ludovici-salvatoris) in two habitats. J Ecol 91:427–437Tutin TG, Heywood VH, Burges NA, Valentine DH, Walters SM, Webb DA (eds) (2001) Flora Europaea, vol 2. Rosaceae to Umbelliferae. Cambridge University Press, CambridgeWright S (1931) Evolution in Mendelian populations. Genetics 16:97–159Zimmerman M (1980a) Reproduction in Polemonium: pre-dispersal seed predation. Ecology 61:502–506Zimmerman M (1980b) Reproduction in Polemonium: competition for pollinators. Ecology 61:497–50

    Taxonomic surrogacy in biodiversity assessments, and the meaning of Linnaean ranks

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    Copyright © 2006 The Natural History MuseumThe majority of biodiversity assessments use species as the base unit. Recently, a series of studies have suggested replacing numbers of species with higher ranked taxa (genera, families, etc.); a method known as taxonomic surrogacy that has an important potential to save time and resources in assesments of biological diversity. We examine the relationships between taxa and ranks, and suggest that species/higher taxon exchanges are founded on misconceptions about the properties of Linnaean classification. Rank allocations in current classifications constitute a heterogeneous mixture of various historical and contemporary views. Even if all taxa were monophyletic, those referred to the same rank would simply denote separate clades without further equivalence. We conclude that they are no more comparable than any other, non-nested taxa, such as, for example, the genus Rattus and the phylum Arthropoda, and that taxonomic surrogacy lacks justification. These problems are also illustrated with data of polychaetous annelid worms from a broad-scale study of benthic biodiversity and species distributions in the Irish Sea. A recent consensus phylogeny for polychaetes is used to provide three different family-level classifications of polychaetes. We use families as a surrogate for species, and present Shannon–Wiener diversity indices for the different sites and the three different classifications, showing how the diversity measures rely on subjective rank allocations.Y. Bertrand, F. Pleijel and G. W. Rous

    Identification of Novel Antimalarial Chemotypes via Chemoinformatic Compound Selection Methods for a High-Throughput Screening Program against the Novel Malarial Target, PfNDH2: Increasing Hit Rate via Virtual Screening Methods

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    Malaria is responsible for approximately 1 million deaths annually; thus, continued efforts to discover new antimalarials are required. A HTS screen was established to identify novel inhibitors of the parasite's mitochondrial enzyme NADH:quinone oxidoreductase (PfNDH2). On the basis of only one known inhibitor of this enzyme, the challenge was to discover novel inhibitors of PfNDH2 with diverse chemical scaffolds. To this end, using a range of ligand-based chemoinformatics methods, ~17000 compounds were selected from a commercial library of ~750000 compounds. Forty-eight compounds were identified with PfNDH2 enzyme inhibition IC(50) values ranging from 100 nM to 40 μM and also displayed exciting whole cell antimalarial activity. These novel inhibitors were identified through sampling 16% of the available chemical space, while only screening 2% of the library. This study confirms the added value of using multiple ligand-based chemoinformatic approaches and has successfully identified novel distinct chemotypes primed for development as new agents against malaria

    Degree of urbanization and gender differences in substance use among Slovak adolescents

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    Substance use among adolescents varies with gender and between countries. Urbanization may contribute to this. The aim of our study is to explore the association between the degree of urbanization and gender differences in adolescent smoking, binge drinking, and cannabis use. A cross-sectional questionnaire survey of Slovak adolescents was used (N = 3,493; mean age = 14.33), stratified by degree of urbanization. The effects of gender and urbanization of the area and their interaction on substance use (smoking, binge drinking, and cannabis) were analyzed using a logistic regression model adjusted for age. Gender and area and their interaction had statistically significant (p <0.01) associations with substance use. The lower the urbanization of the area, the less riskily females behaved. An exception was found in the case of binge drinking where the results of the interaction of gender and degree of urbanization were not significant for the second least urbanized area. Prevalence rate of substance use among girls increased along with an increasing degree of urbanization, while the prevalence rate of substance use among boys remained constant
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