An evaluation of self-administering arithmetic enrichment activities for grades 4, 5, and 6

Thesis (Ed.M.)--Boston Universit

Thresholds for adding degraded tropical forest to the conservation estate

Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems1 that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value4. Here we present empirically defined thresholds for categorizing the conservation value of logged forests, using one of the most comprehensive assessments of taxon responses to habitat degradation in any tropical forest environment. We analysed the impact of logging intensity on the individual occurrence patterns of 1,681 taxa belonging to 86 taxonomic orders and 126 functional groups in Sabah, Malaysia. Our results demonstrate the existence of two conservation-relevant thresholds. First, lightly logged forests (68%) of their biomass removed, and these are likely to require more expensive measures to recover their biodiversity value. Overall, our data confirm that primary forests are irreplaceable5, but they also reinforce the message that logged forests retain considerable conservation value that should not be overlooked

Three-dimensional ultrastructural and immunohistochemical study of immature neurons in the subgranular zone of the rat dentate gyrus

The present study is devoted to three dimensional ultrastructural organization of mitotically dividing immature neurons in dentate gyrus using biophysical approaches. In adult vertebrate brain, cell proliferation persists throughout life mainly in dentate gyrus of the hippocampus (DG) and olfactory bulb. Neurogenesis has been demonstrated using tagged thymidine analogues incorporated into the S phase of the cell cycle, but these may also detect repaired DNA in postmitotic neurons. Recent retroviral labelling has shown that neuronal progenitors/neuroblasts divide and produce functional neurons. Providing ultrastructural evidence of mitotically active cells has proven problematical, not only because of technical issues of identifying dividing cells at electron microscope level, but also because it is difficult to demonstrate unequivocally that neurons identified in the electron microscope are really post mitotic. However by characterising post mitotic cells labelled with BrdU and doublecortin and comparing these with post mitotic cells reconstructed in 3 dimensions from ultrathin serial sections, we have been able to illustrate individual mitotic elements and phases of cells within the GC layer of adult rat dentate gyrus. Here we show dividing cells in metaphase within clusters of immature GCs in subgranular zone (SGZ). These reconstructions provide ultrastructural confirmation that cells expressing doublecortin (DCX), a microtubule associated protein expressed in migrating neurons, localize as clusters in the subgranular zone (SGZ) of dentate gyrus (DG) in the hippocampus during all animal life. Such DG cells with clear synaptic specializations, somatic spines and basal dendrites are exclusive to immature GC that appear to reenter the cell cycle, suggesting the possibility that newly generated neurons within the DG might arise not only from precursors, but also from clusters of immature GC

Risk factors for lymphoproliferative disorders after allogeneic hematopoietic cell transplantation

We evaluated 26 901 patients who underwent allogeneic hematopoietic cell transplantation (HCT) at 271 centers worldwide to define patterns of posttransplantation lymphoproliferative disorders (PTLDs). PTLDs developed in 127 recipients, with 105 (83%) cases occurring within 1 year after transplantation. In multivariate analyses, we confirmed that PTLD risks were strongly associated (P < .001) with T-cell depletion of the donor marrow, antithymocyte globulin (ATG) use, and unrelated or HLA-mismatched grafts (URD/HLA mismatch). Significant associations were also confirmed for acute and chronic graft-versus-host disease. The increased risk associated with URD/HLA-mismatched donors (RR = 3.8) was limited to patients with T-cell depletion or ATG use (P = .004). New findings were elevated risks for age 50 years or older at transplantation (RR = 5.1; P < .001) and second transplantation (RR = 3.5; P < .001). Lower risks were found for T-cell depletion methods that remove both T and B cells (alemtuzumab and elutriation, RR = 3.1; P = .025) compared with other methods (RR = 9.4; P = .005 for difference). The cumulative incidence of PTLDs was low (0.2%) among 21 686 patients with no major risk factors, but increased to 1.1%, 3.6%, and 8.1% with 1, 2, and more than 3 major risk factors, respectively. Our findings identify subgroups of patients who underwent allogeneic HCT at elevated risk of PTLDs for whom prospective monitoring of Epstein-Barr virus activation and early treatment intervention may be particularly beneficial

Thresholds for adding degraded tropical forest to the conservation estate

Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems1 that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value4. Here we present empirically defined thresholds for categorizing the conservation value of logged forests, using one of the most comprehensive assessments of taxon responses to habitat degradation in any tropical forest environment. We analysed the impact of logging intensity on the individual occurrence patterns of 1,681 taxa belonging to 86 taxonomic orders and 126 functional groups in Sabah, Malaysia. Our results demonstrate the existence of two conservation-relevant thresholds. First, lightly logged forests (68%) of their biomass removed, and these are likely to require more expensive measures to recover their biodiversity value. Overall, our data confirm that primary forests are irreplaceable5, but they also reinforce the message that logged forests retain considerable conservation value that should not be overlooked

Thresholds for adding degraded tropical forest to the conservation estate.

Acknowledgements: This study was supported by funding to the Stability of Altered Forest Ecosystems Project by the Sime Darby Foundation. Research permission and site access were provided by the Maliau Basin Management Committee, the Sabah Foundation, Benta Wawasan, Sabah Softwoods, the Innoprise Foundation, the Sabah Forestry Department and the Sabah Biodiversity Centre. R.M.E. is supported by the NOMIS Foundation. Data collection was financed by Australian Research Council grant DP140101541; Bat Conservation International; the British Council Newton-Ungku Omar Fund 216433953; British Ecological Society grant 3256/4035; the Cambridge Trust; the Cambridge University Commonwealth Fund; the Czech Science Foundation (14-32302S); the European Research Council (281986); the European Social Fund and the Czech Republic (CZ.1.07/2.3.00/20.0064); the Fundamental Research Grant Scheme (FRG0302-STWN-1/ 2011), Ministry of Higher Education, Malaysia; FFWS CZU (IGA number A_26_22); the Jardine Foundation; Malaysia Industry Group for High Technology (216433953); the Ministry of Education, Youth and Sports of the Czech Republic (INTER-TRANSFER LTT19018); the Panton Trust; the Primate Society of Great Britain; ProForest; Royal Society of London grant RG130793; the Sime Darby Foundation; the S. T. Lee Fund; the Sir Philip Reckitt Educational Trust; the Tim Whitmore Fund; the Universiti Malaysia Sabah; the University of East Anglia; the University of Kent; the University of Florida Institute of Food and Agricultural Sciences; UK Research and Innovation Natural Environment Research Council grants NE/H011307/1, NE/K016253/1, NE/K016407/1, NE/K016148/1, NE/K0106261/1, NE/K015377/1, NE/L002515/1, NE/L002582/1 and NE/P00363X/1 and studentship 1122589; the Varley Gradwell Travelling Fellowship; and the World Wildlife Fund for Nature. Data collection was supported by R. Adzhar, A. Afendy, N. Arumugam, S. Benedick, V. Bignet, S. Butler, K. Graves, H. E. Hah, H. Heroin, A. Kendall, H. H. Mahsol, D. Mann, J. Miller, S. Milne, J. Mumford, D. Norman, H. Rossleykho, D. Shapiro, K. Sieving, J. Sugau, B. Udell, B. E. Yahya and M. A. Zakaria.Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems1 that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value4. Here we present empirically defined thresholds for categorizing the conservation value of logged forests, using one of the most comprehensive assessments of taxon responses to habitat degradation in any tropical forest environment. We analysed the impact of logging intensity on the individual occurrence patterns of 1,681 taxa belonging to 86 taxonomic orders and 126 functional groups in Sabah, Malaysia. Our results demonstrate the existence of two conservation-relevant thresholds. First, lightly logged forests (68%) of their biomass removed, and these are likely to require more expensive measures to recover their biodiversity value. Overall, our data confirm that primary forests are irreplaceable5, but they also reinforce the message that logged forests retain considerable conservation value that should not be overlooked