15,666 research outputs found
Functional morphology of shortleaf pine (Pinus echinata Mill) fire-adapted traits
Shortleaf pine is one of the most important trees in the southeastern United States for lumber, plywood, and pulpwood production. Throughout its range, shortleaf pine is subjected to frequent fires that can be detrimental to seedlings, often leading to death of the stem (top-kill). Frequent fire occurrence has led to the development of fire-adapted traits in shortleaf pine, specifically thick bark and sprouting from the basal crook after top-kill. The thick bark of shortleaf pine acts as a protective barrier for the cambium layer during a fire; while the basal crook is insulated from fire in the soil, protecting auxiliary buds that can initiate sprouts after top-kill. Our study aims to determine what fire adapted traits are responsible for protecting shortleaf pine throughout its life, from seedling to mature tree. The objectives of our study were to characterize shortleaf pine sprouting after top-kill and the development of bark thickness in relation to stem size. To address our objectives, we top-killed shortleaf pines in the Clemson Experimental Forest, SC and the Ouachita National Forest, AR, and measured bark thickness and counted sprouts from the basal crook after a growing season. We found defense mechanism varied by tree size: smaller trees relied on sprouting after top-kill, while larger trees did not sprout as readily. We hypothesize that the larger trees did not sprout because the thicker bark would have protected the cambium layer to decrease the probability of mortality, ultimately demonstrating a shift in fire-defense mechanisms throughout the life of the tree
Thermal evolution history after collision of North China plate with Yangtze plate
对采自苏北一胶南一大别高压变质构造混杂岩带的片麻岩、糜棱岩和郑庐断裂带上的片麻岩中9个钾长石进行了40Ar-39Ar 年龄测定和多重扩散域(MDD)模式处理, 9个样品的热演化史表明上述地区存在5个不同的快速冷却时段, 并就其可能的构造含义, 提出了华北与扬子板块碰撞后的折返历史过程。40Ar-39Ar analyses and MDD(multiple diffusion domain)model treatements were performed for 9 K-feldspar samples. They were collected from gneiss and mylonite of North Jiangsu-Jiaonan-Dabie tectonic melange belt and Tancheng-Lujiang fault zone. The thermal evolution history exhibits five fast ccoling stages found in these samples.In relation with their possible tectonic implications a recovery process after the collision of the North China plate with the Yangtze plate is suggested here.published_or_final_versio
STUDY ON THE RELATIONSHIP BETWEEN PHYSICAL STRUCTURAL INTEGRALITY AND ECOSYSTEM SERVICES VALUE IN THE RIPARIAN ZONE
Riparian zone is crucial to the health of streams and their surrounding environment. A healthy riparian zone can provide food, habitats, protecting water quality and many other ecological functions and environmental benefits. Evaluating riparian quality is essential to achieve and maintain good stream health, as well as to guarantee the ecological functions that riparian areas provide. In this study, we addressed the consistency of characterizing integrality of ecosystem of a riparian zone in Northeast China with physical structural integrality (PSI) and ecosystem service value (ESV), and explored the relationship between the PSI and ESV. The procedures included (1) evaluation of PSI of the riparian zone based on remote sensing; (2) calculation of the riparian ESV based on basic evaluation units (BEUs); (3) exploration of statistical relationships between the PSI and the ESV by the performance of linear regression. The study concluded that the trend of PSI was the same as the ESV, and they were consistent in describing the quantitative trend of the riparian zone’s ecosystem integrity. There was statistically significant correlation (R = 0.66, P \u3c 0.01 level) between PSI and ESV
A potato NOA gene increased salinity tolerance in Arabidopsis thaliana
The purpose of this study is to produce recombinant StNOA1 in transgenic plants and to test its potential role in plant salt stress responses. The newly cloned StNOA1 gene from Solanum tuberosum L. was inserted into AtnOA1 mutant plant genome by Agrobaterium-mediated floral dip method. Transgene integration was verified by polymerase chain reaction (PCR) in 4 different lines of transgenic Atnoa1. Expression of StNOA1 gene was further analyzed by reverse trancription (RT)-PCR. Physiological analyses indicated that the transgenic line TL9 had higher proline, soluble protein and chlorophyll contents as well as lower content of malondialdehyde (MDA) compared to its receptor, Atnoa1 mutant, under salt stress condition. Root elongation and survival rate in TL9 were significantly higher than those in Atnoa1 seedlings under salt stress. Present study proved that StNOA1 participated in Arabidopsis thaliana salt stress responses and increased its salinity tolerance.Keywords: StNOA1 transformation, Solanum tuberosum, Atnoa1 mutant, salt toleranceAfrican Journal of Biotechnology Vol. 9(36), pp. 5869-5878, 6 September, 201
A numerical study of the impact of climate and emission changes on surface ozone over South China in Autumn time in 2000-2050
2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe
Understanding cohort differences in appraisals of reconstruction priorities of mental health systems in postconflict Liberia
Objective: This study analyzes the relationship between informants’ age and their assessment of mental health needs in postconflict society and examines if mental health needs assessment priorities differ depending upon whether or not the informant was exposed to the Liberian civil war.Method: A cross-sectional survey was conducted in March 2009 to obtain data on mental health needs of Liberian children, adolescents and young adults. A total of 171 individuals were interviewed. The data were analyzed using a two- way ANOVA.Results: Elder respondents expressed a preference for young adults to receive services in a church/mosque (F = 4.020, p < .05); for adolescents in volunteer programs (F = 3.987, p < .05) and for children in sports programs (F = 4.396, p < .05). Experiencing conflict did exert some influence on treatment setting preferences. Those who resided outside Liberia during the conflict cited a preference for traditional healers and medical clinics. However, this preference was for the children and young adult age categories. Those who experienced the civil war reported significantly higher preferences for adolescent services to be located in medical clinics, with traditional healers, and in churches/mosques.Conclusion: This study provides additional support for the premise that the utilization of psychiatric services needs to be viewed from the perspective of Liberians and that there are differences in preferences across groups. Our results suggest that service providers and policy makers take into account the age of the patient when deciding where to locate treatment settings for the population.Keywords: Mental Health; Liberia; Treatment Settings; Elders; Needs AssessmentAfrican Journal of Psychiatry • November 2013, 16(6
Myositis ossificans in the diabetic foot: A review of the literature with an illustrative case series
We report the first cases (to our knowledge) of myositis ossificans (MO) in the ‘diabetic foot’
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Rethinking how external pressure can suppress dendrites in lithium metal batteries
We offer an explanation for how dendrite growth can be inhibited when Li metal pouch cells are subjected to external loads, even for cells using soft, thin separators. We develop a contact mechanics model for tracking Li surface and sub-surface stresses where electrodes have realistically (micron-scale) rough surfaces. Existing models examine a single, micron-scale Li metal protrusion under a fixed local current density that presses more or less conformally against a separator or stiff electrolyte. At the larger, sub-mm scales studied here, contact between the Li metal and the separator is heterogeneous and far from conformal for surfaces with realistic roughness: the load is carried at just the tallest asperities, where stresses reach tens of MPa, while most of the Li surface feels no force at all. Yet, dendrite growth is suppressed over the entire Li surface. To explain this dendrite suppression, our electrochemical/mechanics model suggests that Li avoids plating at the tips of growing Li dendrites if there is sufficient local stress; that local contact stresses there may be high enough to close separator pores so that incremental Li+ ions plate elsewhere; and that creep ensures that Li protrusions are gradually flattened. These mechanisms cannot be captured by single-dendrite-scale analyses
Assessment of the needs of vulnerable youth populations in post-conflict Liberia
Objective: The study examined key informants’ perceptions of the emotional impact of traumatic events, major problems, functional limitations and appropriate treatment settings for children, adolescents, and young adults in post-conflict Liberia.Method: This research is a based on cross-sectional survey conducted between March 30, 2009 and April 30, 2009 in Liberia with 171 local key Liberian informants. Analysis was conducted using mixed methods. The findings we will report were collected in the qualitative portion of the survey. Results: We found that while different interventions were preferred for different types of young people, some interventions were mentioned for all youth and by all age and gender groups of key informants. These includedcounseling, education, and skills training. Also frequently chosen were housing, community reintegration, recreation, and medical care. In general, key informants reported similar concerns regardless of their ages or genders. Notable exceptions to this were in interventions for youth who joined fighting forces. Men over 50 were the only ones to recommend apology and reparations. Similarly, in recommendations for criminals and violent youth, a number of men mentioned prison, whereas the women did not.Conclusion: Our findings suggest that the needs of post-conflict Liberian youth span a variety of domains, including physical, emotional, medical, psychological, and educational. These findings can be used to guide the development of treatment programs for these young people.Keywords: Post-Conflict Liberia; Mental Health Needs Assessment; Children and Adolescent
Manganese dioxide nanosheet functionalized sulfur@PEDOT core-shell nanospheres for advanced lithium-sulfur batteries
MnO2 nanosheet functionalized S@PEDOT core–shell nanospheres demonstrate highly enhanced electrochemical performance for Li–S batteries, benefitting from effectively trapping polysulfides, minimizing polysulfide dissolution, and improving cathode conductivity and wettability.This is the accepted manuscript. The final version is available at http://pubs.rsc.org/en/content/articlelanding/2016/ta/c6ta03211g#!divAbstract
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