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Search Results: 1 - 10 of 464934 matches for " Roger A "
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Mitigating Biodiversity Concerns in Eucalyptus Plantations Located in South China  [PDF]
Roger A. Williams
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.36001
Abstract:

China’s growing economy and changes in policies that encourage afforestation, particularly in the industrial sector, have led vast areas in south China to be planted with eucalyptus. These large areas of eucalyptus plantings have elicited environmental concerns for two primary reasons. First there is a concern related to the water demand of eucalyptus, in which it is feared these large areas of eucalyptus will deplete aquifers and create shortages in water supplies. The second concern is in regard to the reduction in biodiversity across large landscapes, leading to further ecological demises. This paper proposes two ideas to possibly mitigate some of the biodiversity concerns. The first is the interplanting of alder-leaf birch (Betula alnoides), a native but dwindling species in south China, to enhance biodiversity and encourage it’s reestablishment across the landscape. The second is to encourage retention harvests of alder-leaf birch planted within eucalyptus plantations to enhance not only biological diversity but also structural diversity across the landscape. Alder-leaf birch has demonstrated great potential in producing high quality timber and wood for use in furniture manufacturing.

An Investigation of the Carbon Neutrality of Wood Bioenergy  [PDF]
Roger A. Sedjo, Xiaohui Tian
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39114
Abstract: Wood biomass has been viewed as “carbon neutral”—its uses as energy have a zero carbon footprint. Some observers argue that the use of wood biofuels will result in a decrease of the forest stock and a net reduction of the carbon captured in the forest. Such assessments take a static, accounting view of forest systems and do not consider the effects of management in renewing the forest and increasing its extent or ability to sequester carbon. This paper addresses the carbon neutrality debate using a dynamic optimization forest management model to examine the effect on the existing and future forests of a changing demand for wood biomass. The results show that under market optimizing conditions, when future demand is anticipated to increase for significant periods, the response of managers will be to increase the intensity of forest production thereby offsetting much of the carbon released in bioenergy production.
Expanding public health professionals’ roles in promoting and supporting breastfeeding as optimal infant feeding: A pilot study with online tutorial implications  [PDF]
Amna Umer, Roger A. Edwards
Open Journal of Preventive Medicine (OJPM) , 2013, DOI: 10.4236/ojpm.2013.32025
Abstract:

Background: Their knowledge of preventive health, coupled with their dynamic roles in the community, puts public health professionals in a key position to expand their roles in the health promotion and support of breastfeeding as optimal infant feeding. This online tutorial was created to increase public health professionals’ knowledge about breastfeeding and to assess their attitudes in supporting healthy behaviors related to infant feeding as a health promotion strategy. Method: The study utilized an online breastfeeding tutorial based on the US Breast-feeding Committee recommendations for minimum breastfeeding knowledge for health professionals. Pre- and post-tutorial questionnaires assessed breastfeeding knowledge, and an attitudinal survey evaluated attitudes of public health professionals after the tutorial. Exposing public health students to this information can facilitate the early shaping of their attitudes and understanding about the importance of breastfeeding. Results: Fifty-two Northeastern University MPH students and alumni (62% response rate) completed the study. There was an overall gain in participants’ fundamental knowledge regarding breastfeeding as assessed by pre- (77%) to post-tutorial (97%) correct responses (p = 0.00001). The post-tutorial attitudinal survey showed that 92% of participants were comfortable in answering questions about breastfeeding as part of their professional responsibilities. Conclusion: This pilot study highlights the important role that a short online tutorial can play in expanding public health professionals’ knowledge about breastfeeding. Greater use of online methods can enhance awareness of critical health behaviors, such as breastfeeding, that have not received adequate attention in public health curricula. This pilot study provides the foundation for a larger study. Integration of breastfeeding into public health professionals’ core training could support broader social change.

Modelling Open Channel Flows with Vegetation Using a Three-Dimensional Model  [PDF]
Guanghai Gao, Roger A. Falconer, Binliang Lin
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.32013
Abstract: The effects of vegetation on the flow structure are investigated in this paper. In previous studies of modelling vegetated flows, two-equation turbulence models, such as the model, were often used. However, this approach involves a level of uncertainty since the empirical coefficients in these two equations have not yet been satisfactorily obtained for such flow conditions. In addition to this, two extra partial differential equations needing which will result in an increase in the computational cost. The main purpose of the study was therefore to try and acquire accurate velocity profiles without the more advanced two-equation turbulence models. A three-dimensional model using a simple two layer mixing length model was therefore used. The governing hydrodynamic equations were refined to include the effects of drag force induced by vegetation on the flow structure. The model was applied to an experiment flume to study the flow field with vegetations, where experiment data are available. Distributions predicted by the model were compared with laboratory measured ones, with very good agreements being obtained. The results showed that the simple mixing length model could produce accurate complex velocity profile predictions requiring fewer coefficient data and less computation.
Numerical Modelling Sediment-Bacteria Interaction Processes in the Severn Estuary  [PDF]
Guanghai Gao, Roger A. Falconer, Binliang Lin
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.31003
Abstract: Faecal bacteria exist in both free-living and attached forms in estuarine waters. The deposition of sediments can take faecal bacteria out of the water column and to the bed. The sediments can subsequently be re-suspended to the water column, which can then lead to re-suspension of the faecal bacteria of the attached forms back to the water column. Therefore, the fate and transport of faecal bacteria is highly related to the governing sediment transport processes, particularly where these processes are significant, such as the Severn Estuary, UK. However, little attempt has been made to model such processes in terms of predicting the impact of the sediment fluxes on faecal bacteria levels. Details are given of the refinement of a numerical model of faecal bacteria transport, where the sediment transport processes are significant. After testing the sediment-bacteria interaction model favourably against known results in previous study, the model was applied to the Severn Estuary and Bristol Channel, UK, to investigate the impact of suspended sediment fluxes on the corresponding faecal bacteria transport processes. The model predictions have proved to be encouraging, with the results being compared to a traditional faecal bacteria modelling approach, where sediment bacteria interactions were not included. The new model provides improved predictions of faecal bacteria concentrations when sediment transport is included and for the Bristol Channel Severn Estuary it can be seen that the effects of the sediments on the bacterial levels in the water column can be significant.
Review. Comparative structures and evolution of mammalian lipase I (LIPI) genes and proteins: A close relative of vertebrate phospholipase LIPH  [PDF]
Roger S. Holmes, Laura A. Cox
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.412A142
Abstract:

Lipase I (enzyme name LIPI or LPDL) (gene name LIPI [human] or Lipi [mouse]) is a phospholipase which generates 2-acyl lysophosphatidic acid (LPA), a lipid mediator required for maintaining homeostasis of diverse biological functions and in activating cell surface recaptors. Bioinformatic methods were used to predict the amino acid sequences, secondary and tertiary structures and gene locations for LIPI genes and encoded proteins using data from several mammalian genome projects. LIPI is located on human chromosome 21 and is distinct from other phospholipase A1-like genes (LIPH and PS-PLA1). Mammalian LIPI genes contained 10 (human) or 11 (mouse) coding exons transcribed predominantly on the negative DNA strand. Mammalian LIPI protein subunits shared 61% - 99% sequence identities and exhibited sequence alignments and identities for key LIPI amino acid residues as well as extensive conservation of predicted secondary and tertiary structures with those previously reported for pancreatic lipase (PL), with “N-signal peptide”, “lipase” and “plat” structural domains. Comparative studies of mammalian LIPI sequences with LIPH, PS-PLA1 and pancreatic lipase (PL) confirmed predictions for LIPI N-terminal signal peptides (residues 1 - 15); predominantly conserved mammalian LIPI N-glycosylation sites (63NNSL and 396NISS for human LIPI); active site “triad” residues (Ser159; Asp183; His253); disulfide bond residues (238 - 251; 275 - 286; 289 - 297; 436 - 455); and a 12 residue “active site lid”, which is shorter than for other lipases examined. Phylogenetic analyses supported a hypothesis that LIPI arose from a vertebrate LIPH gene duplication event within a mammalian common ancestral genome. In addition, LIPI, LIPH and PL-PLA1 genes were distinct from the vascular lipase (LIPG, LIPC and LPL) and pancreatic lipase (PL) gene families.

Filtered Leapfrog Time Integration with Enhanced Stability Properties  [PDF]
Ari Aluthge, Scott A. Sarra, Roger Estep
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.47145
Abstract: The Leapfrog method for the solution of Ordinary Differential Equation initial value problems has been historically popular for several reasons. The method has second order accuracy, requires only one function evaluation per time step, and is non-dissipative. Despite the mentioned attractive properties, the method has some unfavorable stability properties. The absolute stability region of the method is only an interval located on the imaginary axis, rather than a region in the complex plane. The method is only weakly stable and thus exhibits computational instability in long time integrations over intervals of finite length. In this work, the use of filters is examined for the purposes of both controlling the weak instability and also enlarging the size of the absolute stability region of the method.
Use of Maximum Entropy Modeling in Wildlife Research
Roger A. Baldwin
Entropy , 2009, DOI: 10.3390/e11040854
Abstract: Maximum entropy (Maxent) modeling has great potential for identifying distributions and habitat selection of wildlife given its reliance on only presence locations. Recent studies indicate Maxent is relatively insensitive to spatial errors associated with location data, requires few locations to construct useful models, and performs better than other presence-only modeling approaches. Further advances are needed to better define model thresholds, to test model significance, and to address model selection. Additionally, development of modeling approaches is needed when using repeated sampling of known individuals to assess habitat selection. These advancements would strengthen the utility of Maxent for wildlife research and management.
International Conference on the Biology of the Mammary Gland. Tours, France (16-18 September 1999)
Roger A Clegg
Breast Cancer Research , 1999, DOI: 10.1186/bcr32
Abstract: Around 175 participants gathered in France's Loire Valley for this unashamedly multi disciplinary meeting. The location in Tours was particularly appropriate, since it is near to the final resting place of that archetypal multidisciplinarian, Leonardo da Vinci, whose memory it celebrates as an honorary son of the city. The glossy and well-appointed Congress Centre Vinci, in which the conference took place, exemplifies this continuing homage.A core aim of the COST 825 action has been to bring together the different scientific traditions which, while sharing an interest in mammary gland biology, have historically remained separate and even remote from one another. The medical (breast cancer) and the agricultural (lactation and animal production) traditions represent the extremes of this separation. The eight sessions of the conference, most with six invited speakers, complemented by 64 posters, picked out key areas across this multi disciplinary spectrum of mammary gland biology.A strong undercurrent of mammary cell culture technology ran through this session. Catherine Niemann, (reporting on work at the Max Delbrueck Center for Molecular Medicine, Berlin, Germany) used a cell-line, EpH4, cultured on matrigel to demonstrate distinct morphogenic programmes provoked by hepatocyte growth factor and neuregulin, and transduced via independent receptor kinase pathways. Jesus Soriano (University of Geneva Medical School, Switzerland) discussed the ability of oncogenes and tumour suppressors to modify the growth characteristics of TAC-2 cells on plastic and in collagen gels. Clive Dickson (Imperial Cancer Research Fund, London, UK) combined targeted transgene technology with transplantation into cleared mammary fat pads to uncover requirements for fibroblast growth factor (FGF)-receptor and cyclin D1 in overlapping but different aspects of mammary growth and differentiation. Paul Edwards (Department of Pathology, Cambridge, UK) further expounded on his elegant techniques of m
O uso de drogas anti-reumáticas na gravidez
Levy, Roger A.;
Revista Brasileira de Reumatologia , 2005, DOI: 10.1590/S0482-50042005000300007
Abstract: the prescription of anti-rheumatic drugs in fertile patients should take into account the current knowledge about their effects on conception, pregnancy and lactation. judicious advice and pregnancy planning is ideal when possible. with the incorporation of new substances and the constant appearance of recent data in the literature this subject has to be continuously updated. the fda risk factor rating is sometimes contradictory to our practice, in part because results from animal studies may not be directly applicable to humans. biologic response modifiers seem to be safely used during pregnancy, since they are large molecules that are not capable of crossing the placenta. non-steroidal anti-inflammatory drugs including specific cox-2 inhibitors may impair implantation of the ovum but can be used once pregnancy is under way, they should be avoided after 32 weeks, when there is a relationship with fetal complications. cox-2 inhibitors must be avoided due to its risk of renal mal-formation. low-dose aspirin can be used safely during pregnancy. low molecular weight heparins are preferred, since the unfractionated heparins have an increased risk of inducing thrombocytopenia and bleeding. hydroxychloroquine is used and in fact recommended in lupus pregnancy with patients' benefits and no fetal risk. warfarin is teratogenic if given between the 6th and 9th gestational weeks, but can be used during the second and third until 34 weeks, when it should be withdrawn in order to avoid the risk of neonatal bleeding. intravenous immunoglobulin is recommended for difficult antiphospholipid cases and is being studied to prevent the congenital heart block of neonatal lupus. prednisone and prednisolone use is limited to the least effective dose since they do not reach fetal circulation, but can induce maternal side effects. azathioprine and cyclosporine are used when necessary with no apparent fetal harm. methotrexate and leflunomide must be avoided by all means and the treatment st
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