236 research outputs found

    The role of forest genetic resources in responding to biotic and abiotic factors in the context of anthropogenic climate change

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    The current distribution of forest genetic resources on Earth is the result of a combination of natural processes and human actions. Over time, tree populations have become adapted to their habitats including the local ecological disturbances they face. As the planet enters a phase of human-induced climate change of unprecedented speed and magnitude, however, previously locally-adapted populations are rendered less suitable for new conditions, and ‘natural’ biotic and abiotic disturbances are taken outside their historic distribution, frequency and intensity ranges. Tree populations rely on phenotypic plasticity to survive in extant locations, on genetic adaptation to modify their local phenotypic optimum or on migration to new suitable environmental conditions. The rate of required change, however, may outpace the ability to respond, and tree species and populations may become locally extinct after specific, but as yet unknown and unquantified, tipping points are reached. Here, we review the importance of forest genetic resources as a source of evolutionary potential for adaptation to changes in climate and other ecological factors. We particularly consider climate-related responses in the context of linkages to disturbances such as pests, diseases and fire, and associated feedback loops. The importance of management strategies to conserve evolutionary potential is emphasised and recommendations for policy-makers are provided

    Morphology of the archaellar motor and associated cytoplasmic cone in Thermococcus kodakaraensis

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    Archaeal swimming motility is driven by archaella: rotary motors attached to long extracellular filaments. The structure of these motors, and particularly how they are anchored in the absence of a peptidoglycan cell wall, is unknown. Here, we use electron cryotomography to visualize the archaellar basal body in vivo in Thermococcus kodakaraensis KOD1. Compared to the homologous bacterial type IV pilus (T4P), we observe structural similarities as well as several unique features. While the position of the cytoplasmic ATPase appears conserved, it is not braced by linkages that extend upward through the cell envelope as in the T4P, but rather by cytoplasmic components that attach it to a large conical frustum up to 500 nm in diameter at its base. In addition to anchoring the lophotrichous bundle of archaella, the conical frustum associates with chemosensory arrays and ribosome‐excluding material and may function as a polar organizing center for the coccoid cells

    On Central Charges and Hamiltonians for 0-brane dynamics

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    We consider general properties of central charges of zero branes and associated duality invariants, in view of their double role, on the bulk and on the world volume (quantum-mechanical) theory. A detailed study of the BPS condition for the mass spectrum arising from toroidal compactifications is given for 1/2, 1/4 and 1/8 BPS states in any dimensions. As a byproduct, we retreive the U-duality invariant conditions on the charge (zero mode) spectrum and the orbit classification of BPS states preserving different fractions of supersymmetry. The BPS condition for 0-branes in theories with 16 supersymmetries in any dimension is also discussed.Comment: 23 pages, latex fil

    The Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis examined long-term glomerular dysfunction in childhood cancer survivors

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    This investigation aimed to evaluate glomerular dysfunction among childhood cancer survivors in comparison with matched controls from the general population. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis, a nationwide cross-sectional cohort study, 1024 survivors five or more years after diagnosis, aged 18 or more years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated. In addition, 500 age- and sex-matched controls from Lifelines, a prospective population-based cohort study in the Netherlands, participated. At a median age of 32.0 years (interquartile range 26.6-37.4), the glomerular filtration rate was under 60 ml/min/1.73m2 in 3.7% of survivors and in none of the controls. Ten survivors had kidney failure. Chronic kidney disease according to age-thresholds (glomerular filtration rate respectively under 75 for age under 40, under 60 for ages 40-65, and under 40 for age over 65) was 6.6% in survivors vs. 0.2% in controls. Albuminuria (albumin-to-creatinine ratio over3 mg/mmol) was found in 16.2% of survivors and 1.2% of controls. Risk factors for chronic kidney disease, based on multivariable analyses, were nephrectomy (odds ratio 3.7 (95% Confidence interval 2.1-6.4)), abdominal radiotherapy (1.8 (1.1-2.9)), ifosfamide (2.9 (1.9-4.4)) and cisplatin over 500 mg/m2 (7.2 (3.4-15.2)). For albuminuria, risk factors were total body irradiation (2.3 (1.2-4.4)), abdominal radiotherapy over 30 Gy (2.6 (1.4- 5.0)) and ifosfamide (1.6 (1.0-2.4)). Hypertension and follow-up 30 or more years increased the risk for glomerular dysfunction. Thus, lifetime monitoring of glomerular function in survivors exposed to these identified high risk factors is warranted.</p

    Hypertension in long-term childhood cancer survivors after treatment with potentially nephrotoxic therapy; DCCSS-LATER 2:Renal study

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    Purpose: To evaluate the prevalence of and risk factors for hypertension in childhood cancer survivors (CCSs) who were treated with potentially nephrotoxic therapies. Methods: In the Dutch Childhood Cancer Survivor Study LATER cohort part 2 renal study, 1024 CCS ≄5 years after diagnosis, aged ≄18 years at study participation, treated between 1963 and 2001 with nephrectomy, abdominal radiotherapy, total body irradiation (TBI), cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide (≄1 g/m2 per single dose or ≄10 g/m2 total) or haematopoietic stem cell transplantation participated and 500 controls from Lifelines. Hypertension was defined as blood pressure (BP) (mmHg) systolic ≄140 and/or diastolic ≄90 or receiving medication for diagnosed hypertension. At the study visit, the CKD-EPI 2012 equation including creatinine and cystatin C was used to estimate the glomerular filtration rate (GFR). Multivariable regression analyses were used. For ambulatory BP monitoring (ABPM), hypertension was defined as BP daytime: systolic ≄135 and/or diastolic ≄85, night time: systolic ≄120 and/or diastolic ≄70, 24-h: systolic ≄130 and/or diastolic ≄80. Outcomes were masked hypertension (MH), white coat hypertension and abnormal nocturnal dipping (aND). Results: Median age at cancer diagnosis was 4.7 years (interquartile range, IQR 2.4–9.2), at study 32.5 years (IQR 27.7–38.0) and follow-up 25.5 years (IQR 21.4–30.3). The prevalence of hypertension was comparable in CCS (16.3%) and controls (18.2%). In 12% of CCS and 17.8% of controls, hypertension was undiagnosed. A decreased GFR (<60 ml/min/1.73 m2) was associated with hypertension in CCS (OR 3.4, 95% CI 1.4–8.5). Risk factors were abdominal radiotherapy ≄20 Gy and TBI. The ABPM-pilot study (n = 77) showed 7.8% MH, 2.6% white coat hypertension and 20.8% aND. Conclusion: The prevalence of hypertension was comparable among CCS who were treated with potentially nephrotoxic therapies compared to controls, some of which were undiagnosed. Risk factors were abdominal radiotherapy ≄20 Gy and TBI. Hypertension and decreased GFR were associated with CCS. ABPM identified MH and a ND

    Familial pulmonary alveolar proteinosis caused by mutations in CSF2RA

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    Primary pulmonary alveolar proteinosis (PAP) is a rare syndrome characterized by accumulation of surfactant in the lungs that is presumed to be mediated by disruption of granulocyte/macrophage colony-stimulating factor (GM-CSF) signaling based on studies in genetically modified mice. The effects of GM-CSF are mediated by heterologous receptors composed of GM-CSF binding (GM-CSF-Rα) and nonbinding affinity-enhancing (GM-CSF-RÎČ) subunits. We describe PAP, failure to thrive, and increased GM-CSF levels in two sisters aged 6 and 8 yr with abnormalities of both GM-CSF-Rα–encoding alleles (CSF2RA). One was a 1.6-Mb deletion in the pseudoautosomal region of one maternal X chromosome encompassing CSF2RA. The other, a point mutation in the paternal X chromosome allele encoding a G174R substitution, altered an N-linked glycosylation site within the cytokine binding domain and glycosylation of GM-CSF-Rα, severely reducing GM-CSF binding, receptor signaling, and GM-CSF–dependent functions in primary myeloid cells. Transfection of cloned cDNAs faithfully reproduced the signaling defect at physiological GM-CSF concentrations. Interestingly, at high GM-CSF concentrations similar to those observed in the index patient, signaling was partially rescued, thereby providing a molecular explanation for the slow progression of disease in these children. These results establish that GM-CSF signaling is critical for surfactant homeostasis in humans and demonstrate that mutations in CSF2RA cause familial PAP

    Psychosexual development, sexual functioning and sexual satisfaction in long-term childhood cancer survivors:DCCSS-LATER 2 sexuality substudy

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    Objectives: Childhood cancer may negatively impact childhood cancer survivors' (CCS) sexuality. However, this is an understudied research area. We aimed to describe the psychosexual development, sexual functioning and sexual satisfaction of CCS, and identify determinants for these outcomes. Secondarily, we compared the outcomes of a subsample of emerging adult CCS to the Dutch general population. Methods: From the Dutch Childhood Cancer Survivor Study LATER cohort (diagnosed 1963–2001), 1912 CCS (18–71 years, 50.8% male) completed questions on sexuality, psychosocial development, body perception, mental and physical health. Multivariable linear regressions were used to identify determinants. Sexuality of CCS age 18–24 (N = 243) was compared to same-aged references using binomial tests and t-tests. Results: One third of all CCS reported hindered sexuality due to childhood cancer, with insecure body the most often reported reason (44.8%). Older age at study, lower education, surviving central nervous system cancer, poorer mental health and negative body perception were identified as determinants for later sexual debut, worse sexual functioning and/or sexual satisfaction. CCS age 18–24 showed significantly less experience with kissing (p = 0.014), petting under clothes (p = 0.002), oral (p = 0.016) and anal sex (p = 0.032) when compared to references. No significant differences with references were found for sexual functioning and sexual satisfaction, neither among female CCS nor male CCS age 18–24. Conclusions: Emerging adult CCS reported less experience with psychosexual development, but similar sexual functioning and sexual satisfaction compared to references. We identified determinants for sexuality, which could be integrated in clinical interventions for CCS at risk for reduced sexuality.</p

    Beyond timber: balancing demands for tree resources between concessionaires and villagers

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    Extensive areas of the Congo Basin forest are allocated to timber concessionaires. These forests also harbour and support village populations, including indigenous Baka people, who depend on forest foods obtained directly from trees (fruits, oils and caterpillars). Most food-producing tree species are harvested by concessionaires for timber. We documented the availability and abundance of three food tree species around four villages and in two neighboring timber concessions in Cameroon. Data was used to determine the importance of timber concessions as sources of food for local people to provide a foundation for governance arrangements that consider local needs for foods from timber trees. Discussions with concessionaires revealed that some of them have voluntarily refrained from extracting timber species of interest to villagers for their nontimber products. This is either to avoid conflict with villagers, or because regulations have been promulgated to safeguard these resources. The interplay between internal village dynamics, regulations and their implementation by forest guards, and the actions of timber concessions create a complex arena for addressing rights to forest resources. This paper provides information on the accessibility and availability of multiple use timber species as a foundation for negotiations and governance arrangements between concessionaires and local communities
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