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1.
S. J. Vermeiden B. M. Campbell G. E. Matzke 《Human ecology: an interdisciplinary journal》1996,24(4):479-491
The objectives of this paper are to quantify the annual household consumption of wood for different purposes and to investigate the types of wood used for each purpose. Households in part of Gokwe Communal Area, a rural Zimbabwean study area in which wood is considered plentiful, use a mean 4.8 tons per household per year (t hh
–1
yr
–1
) of wood for fuel, comprising 4.0 t to meet day-to-day requirements and 0.8 t for special occasions and beer brewing. In addition, building and repairing wooden structures require 3.5 t hh
–1
yr
–1
The total annual consumption is at most 8.3 t hh
–1
yr
–1
depending on the amount of wood in wooden structures that is recycled into new structures or as firewood. Wide variation around the mean annual consumption is expected because of differences among households and errors associated with calculation. The different purposes to which wood is put require wood of different types. Firewood for day-to-day use consists of small dead pieces collected in headloads. For brewing and special occasions large logs are used. Poles and small branches are freshly cut for wooden structures, with poles of particular girths and lengths being used for different components of the structures. Species is also taken into account in the collection of wood for fuel and construction. Disaggregation of the yearly consumption by site and species is important to the assessment of supply and demand of wood. 相似文献
2.
Gerald McKenna P Finbarr Allen Noel Woods Denis O’Mahony Cristiane DaMata Michael Cronin Charles Normand 《Gerodontology》2013,30(3):207-213
doi: 10.1111/j.1741‐2358.2012.00665.x A preliminary report of the cost‐effectiveness of tooth replacement strategies for partially dentate elders Objective: To compare the cost‐effectiveness of conventional treatment using partial dentures with functionally orientated treatment to replace missing teeth for partially dentate elders using a randomised controlled clinical trial. Background: In many countries, including the Republic of Ireland, the only publically funded treatment option offered to partially dentate older patients is a removable partial denture. However, evidence suggests that these removable prostheses are unpopular with patients and can potentially increase the risk of further dental disease and subsequent tooth loss. Materials and Methods: Fourty‐four partially dentate patients aged 65 years and older were recruited. Patients were randomly assigned to the two treatment arms of the study. The conventional treatment group received removable partial dentures to replace all missing natural teeth. The functionally orientated group was restored to a Shortened Dental Arch (SDA) of 10 occluding contacts using resin‐bonded bridgework (RBB). The costs associated with each treatment were recorded. Effectiveness was measured in terms of the impact on oral health‐related quality of life (OHRQoL) using OHIP‐14. Results: Both groups reported improvements in OHRQoL 1 month after completion of treatment. The conventional treatment group required 8.3 clinic visits as compared to 4.4 visits for the functionally orientated group. The mean total treatment time was 183 min 19 s for the conventional group vs. 124 min 8 s for the functionally orientated group. The average cost of treatment for the conventional group was 487.74 Euros compared to 356.20 Euros for the functional group. Conclusions: Functionally orientated treatment was more cost‐effective than conventional treatment in terms of treatment effect and opportunity costs to the patients’ time. 相似文献
3.
目的 筛选稀有鮈鲫HAN近交系遗传质量检测标记.方法 采用鳞片活体移植和同工酶聚丙烯酰胺凝胶电泳法对稀有鮈鲫HAN近交系的遗传纯度进行检测.结果 在免疫标记分析中,鳞片同体移植存活率为96.7%以上,野生群体移植存活率为7.4%,而HAN系F22鳞片异体移植的成功率为80%,显著高于野生群体.在生化标记分析中,在HAN系F22中无多态性位点,不同个体的同工酶谱呈现高度一致,在野生群体中有2个多态位点即est2和est3,多态位点的比例为15.56%.结论 经过多代近亲交配,稀有鮈鲫HAN近交系生化标记基因已经纯合,鳞片异体移植存活率达到80%,表明HAN系具有较高的遗传均一性.选用鳞片的异体移植及酯酶和肌蛋白分别作为免疫和生化标记对稀有鮈鲫HAN近交系进行遗传质量检测是可行的. 相似文献
4.
利用17对微卫星引物对稀有鮈鲫(Gobiocypris rarus)野生群体和近交系F20和F22进行了遗传分析。结果表明在野生群体中17个微卫星位点均为多态位点,但在F20中仅有6个多态位点,F22中则仅有4个多态位点。在野生群体中共检测到64个等位基因,F20、F22分别为26、21个。近交系的平均基因纯合率均较高,其中F20为86.18%,F22达91.96%,而野生群体平均基因纯合率为46.84%。近交系平均杂合度和平均多态信息含量均较野生群体低。在近交系F20和F22中,群体间遗传相似性指数最大,其遗传距离最小,说明二者之间的亲缘关系最近。HAN系遗传多样性明显降低,已具有较高的遗传纯度。 相似文献
5.
Mortola JP 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2004,137(4):723-730
In the avian embryo at term we measured the ventilatory response to hyperoxia, which lowers the chemoreceptor activity, to test the hypothesis that the peripheral chemoreceptors are tonically functional. Measurements of pulmonary ventilation (VE) were conducted in chicken embryos during the external pipping phase, at 38 degrees C, during air and hyperoxia, and during hypercapnia in air or in hyperoxia. Hyperoxia (95% O2) maintained for 30 min lowered VE by 15-20%, largely because of a reduction in breathing frequency (f). The oxygen consumption and carbon dioxide production of the embryo were not altered. The hyperoxic drop of VE was more marked in those embryos, which had higher values of normoxic VE. Hypercapnia, whether 2 or 5% CO2, increased VE, almost exclusively because of the increase in tidal volume (VT). The increase in VT was less pronounced when hypercapnia was associated with hyperoxia, and f slightly decreased. Hence, in hyperoxia, the VE response to CO2 was less than in air. The results are in support of the hypothesis that in the avian embryo, after the onset of breathing, the peripheral chemoreceptors exert a tonic facilitatory input on . This differs from neonatal mammals, where the chemoreceptors have minimal or no activity at birth, presumably because the increased arterial oxygenation with the onset of air breathing is a much more sudden phenomenon in mammals than it is in birds. 相似文献
6.
平菇对不同碳氮比麦草培养料主要组分的降解研究 总被引:4,自引:0,他引:4
研究平菇对不同碳氮比麦草培养料主要组分的降解结果表明,麦草栽培平菇后,C/N比值普遍下降,下降幅度随C/N比增加而加大,下降趋势与基物失重、粗纤维降解、呼吸消耗相一致。菇产量以C/N比50—60:1最高,但菇产量的高低与基物失重、粗纤维减少、呼吸损耗多少没有关系,而与培养料的C/N比值却有明显的曲线关系。 相似文献
7.
In the UK, wood cricket (Nemobius sylvestris) is a ‘Species of Conservation Concern’, being restricted to only three areas in southern England. Little information is
available on the specific habitat requirements of this species. In 2006, a field investigation within three woodlands on the
Isle of Wight was undertaken to identify its habitat preferences. Factors positively influencing wood cricket presence within
woodlands included the presence of a well-developed leaf litter layer, relatively low ground vegetation cover and height,
low canopy cover and relatively short distances between individual populations. Regression models identified the degree of
isolation and variables describing vegetation structure as the main predictors for wood cricket presence within woodland fragments.
The results of this study indicate the preference of wood cricket for open wooded edges. Conservation efforts for this species
should focus on continuation of regular management activities aimed at providing permanent open edge habitat within woodlands,
to maintain viable populations. 相似文献
8.
Improvements in pancreatic islet transplantation for treatment of diabetes are hindered by the absence of meaningful islet quality assessment methods. Oxygen consumption rate (OCR) has previously been used to assess the quality of organs and primary tissue for transplantation. In this study, we describe and characterize a stirred microchamber for measuring OCR with small quantities of islets. The device has a titanium body with a chamber volume of about 200 microL and is magnetically stirred and water jacketed for temperature control. Oxygen partial pressure (pO(2)) is measured by fluorescence quenching with a fiber optic probe, and OCR is determined from the linear decrease of pO(2) with time. We demonstrate that measurements can be made rapidly and with high precision. Measurements with betaTC3 cells and islets show that OCR is directly proportional to the number of viable cells in mixtures of live and dead cells and correlate linearly with membrane integrity measurements made with cells that have been cultured for 24 h under various stressful conditions. 相似文献
9.
Effect of chitosan on physiological, morphological, and ultrastructural characteristics of wood-degrading fungi 总被引:2,自引:0,他引:2
Tripti Singh Damiano Vesentini Adya P. Singh Geoffrey Daniel 《International biodeterioration & biodegradation》2008,62(2):116-124
An investigation was undertaken to understand the mechanism(s) by which chitosan exerts its antifungal effects against the wood-degrading fungi Sphaeropsis sapinea and Trichoderma harzianum. Exposure to increasing concentrations of chitosan caused an increase in the amount of hydrogen peroxide accumulation in cultures of S. sapinea, which was accompanied by a decrease in superoxide formation. The same effect was not observed in T. harzianum. Potassium ion leakage was an early event for both test fungi, leakage being more pronounced for S. sapinea than T. harzianum for the first 5 min, particularly at higher concentrations of chitosan treatment. Fluorescence microscopy provided evidence that the effect of chitosan on fungal hyphae was mediated through alterations in the plasma membrane properties. Chitosan also severely affected fungal morphology. Increasing concentrations of chitosan induced excessive branching, vacuolation, and a reduction in hyphal diameter. Transmission electron microscopy, which showed more severe ultrastructural changes in S. sapinea hyphae from chitosan treatment as compared to T. harzianum, provided valuable complementary information. The data suggest that the plasma membrane may be the primary target of chitosan action, and that the two fungi differ in the extent to which they are affected. 相似文献
10.
Three wild-type diploid yeast strains Saccharomyces ellipsoideus and Saccharomyces cerevisiae and five radiosensitive mutants of S. cerevisiae in the diploid state were irradiated with gamma-rays from 60Co and alpha-particles from 239Pu in the stationary phase of growth. Survival curves and the kinetics of the liquid holding recovery were measured. It was shown that the irreversible component was enhanced for the densely ionizing radiation in comparison to the low-LET radiation while the probability of the recovery was identical for both the low- and high-LET radiations for all the strains investigated. It means that the recovery process itself is not damaged after densely ionizing radiation and the enhanced RBE of the high-LET radiation may be caused by the increased yield of the irreversible damage. A parent diploid strain and all its radiosensitive mutants showed the same probability for recovery from radiation damage. Thus, the mechanism of the enhanced radiosensitivity of the mutant cells might not be related to the damage of the repair systems themselves but with the production of some kind of radiation damage from which cells are incapable to recover. 相似文献
11.
基于光温的温室标准切花菊品质预测模型 总被引:3,自引:2,他引:1
根据光温对菊花品质的影响,通过不同定植期和不同品种试验,建立了以生理辐热积(physiological product of thermal effectiveness and PAR, PTEP)为尺度的温室标准切花菊品质预测模型,并用独立的试验数据对模型进行检验.结果表明:模型对温室标准切花菊的展叶数、单株叶面积、株高、茎粗、节间长和花径的模拟值与实测值的符合度较好,模拟值与实测值基于1∶1线的决定系数(R2)和预测相对误差(RSE)分别为0.99、0.98、0.98、0.92、0.87、0.88和5.5%、6.5%、5.9%、4.1%、11.2%、12.4%.表明该品质预测模型预测精度高、实用性强,可为温室标准切花菊生产中的光温调控提供理论依据和决策支持. 相似文献
12.
目前国内对生态系统服务的研究多是从供给的角度对生态系统服务的功能量和价值量进行评估,对生态系统服务的消费及其与供给的相互关系重视不够。以传统农业区贵州省从江县为例,利用不同计量方法对当地居民对生态系统服务的消费进行测算,并对当地的生态系统服务供给-消费平衡关系进行衡量。结果表明:(1)价值量方法、能值分析方法和生态足迹方法的计量结果都说明,从江县居民对供给服务的消费构成了生态系统服务消费的主体部分;(2)运用能值分析方法和生态足迹方法得到的负荷能力系数表明,从江县2007年基本上处于生态系统服务供需平衡状态。尽管几种方法各有优缺点,但都不失为计量生态系统服务消费的有效方法。 相似文献
13.
Geiziane Tessarolo Richard Ladle Thiago Rangel Joaquin Hortal 《Ecology and evolution》2017,7(17):6863-6870
Spatial and/or temporal biases in biodiversity data can directly influence the utility, comparability, and reliability of ecological and evolutionary studies. While the effects of biased spatial coverage of biodiversity data are relatively well known, temporal variation in data quality (i.e., the congruence between recorded and actual information) has received much less attention. Here, we develop a conceptual framework for understanding the influence of time on biodiversity data quality based on three main processes: (1) the natural dynamics of ecological systems—such as species turnover or local extinction; (2) periodic taxonomic revisions, and; (3) the loss of physical and metadata due to inefficient curation, accidents, or funding shortfalls. Temporal decay in data quality driven by these three processes has fundamental consequences for the usage and comparability of data collected in different time periods. Data decay can be partly ameliorated by adopting standard protocols for generation, storage, and sharing data and metadata. However, some data degradation is unavoidable due to natural variations in ecological systems. Consequently, changes in biodiversity data quality over time need be carefully assessed and, if possible, taken into account when analyzing aging datasets. 相似文献
14.
Disperser effectiveness is the contribution a disperser makes to the future reproduction of a plant. Although it is a key notion in studies of seed dispersal by animals, we know little about what determines the effectiveness of a disperser. The role of the present paper is to review the available information and construct a hierarchical framework for viewing the components of disperser effectiveness.Effectiveness has both quantitative and qualitative components. The quantity of seed dispersal depends on (A) the number of visits made to the plant by a disperser and (B) the number of seeds dispersed per visit. The quality of seed dispersal depends on (A) the quality of treatment given a seed in the mouth and in the gut and (B) the quality of seed deposition as determined by the probability that a deposited seed will survive and become an adult. In this paper I review the ways disperser behavior, morphology and physiology can influence these major components of disperser effectiveness, and when data permit present preliminary analyses of relationships among components. 相似文献
15.
R. Lal 《Critical Reviews in Plant Sciences》1998,17(4):319-464
Soil erosion is a global issue because of its severe adverse economic and environmental impacts. Economic impacts on productivity may be due to direct effects on crops/plants on-site and off-site, and environmental consequences are primarily off-site due either to pollution of natural waters or adverse effects on air quality due to dust and emissions of radiatively active gases. Off-site economic effects of erosion are related to the damage to civil structure, siltation of water ways and reservoirs, and additional costs involved in water treatment. There are numerous reports regarding the on-site effects of erosion on productivity. However, a vast majority of these are from the U.S., Canada, Australia, and Europe, and only a few from soils of the tropics and subtropics. On-site effects of erosion on agronomic productivity are assessed with a wide range of methods, which can be broadly grouped into three categories: agronomic/soil quality evaluation, economic assessment, and knowledge surveys. Agronomic methods involve greenhouse and field experiments to assess erosion-induced changes in soil quality in relation to productivity. A widely used technique is to establish field plots on the same soil series but with different severity of past erosion. Different erosional phases must be located on the same landscape position. Impact of past erosion on productivity can also be assessed by relating plant growth to the depth of a root-restrictive horizon. Impact of current erosion rate on productivity can be assessed using field runoff plots or paired watersheds, and that of future erosion using topsoil removal and addition technique. Economic evaluation of the on-site impact involves assessment of the losses of plant available water and nutrients and other additional inputs needed due to erosion. Knowledge surveys are conducted as a qualitative substitute for locations where quantitative data are not available. Results obtained from these different techniques are not comparable, and there is a need to standardize the methods and develop scaling procedures to extrapolate the data from plot or soil level to regional and global scale. There is also a need to assess on-site impact of erosion in relation to soil loss tolerance, soil life, soil resilience or ease of restoration, and soil management options for sustainable use of soil and water resources. Restoration of degraded soils is a high global priority. If about 1.5×109?ha of soils in the world prone to erosion can be managed to effectively control soil erosion, it would improve air and water quality, sequester C in the pedosphere at the rate of about 1.5?Pg/year, and increase food production. The risks of global annual loss of food production due to accelerated erosion may be as high as 190×106?Mg of cereals, 6×106?Mg of soybeans, 3×106?Mg of pulses, and 73×106?Mg of roots and tubers. The actual loss may depend on weather conditions during the growing season, farming systems, soil management, and soil ameliorative input used. Erosion-caused losses of food production are most severe in Asia, Sub-Saharan Africa, and elsewhere in the tropics rather than in other regions. 相似文献
16.
The Functional Role of β Subunits in Oligomeric P-Type ATPases 总被引:5,自引:0,他引:5
Käthi Geering 《Journal of bioenergetics and biomembranes》2001,33(5):425-438
Na,K-ATPase and gastric and nongastric H,K-ATPases are the only P-type ATPases of higher organisms that are oligomeric and are associated with a subunit, which is obligatory for expression and function of enzymes. Topogenesis studies suggest that subunits have a fundamental and unique role in K+-transporting P-type ATPases in that they facilitate the correct membrane integration and packing of the catalytic subunit of these P-type ATPases, which is necessary for their resistance to cellular degradation, their acquisition of functional properties, and their routing to the cell surface. In addition to this chaperone function, subunits also participate in the determination of intrinsic transport properties of Na,K- and H,K-ATPases. Increasing experimental evidence suggests that assembly is a highly ordered, isoform-specific process, which is mediated by multiple interaction sites that contribute in a coordinate, multistep process to the structural and functional maturation of Na,K- and H,K-ATPases. 相似文献
17.
Sikorski J Lapidus A Chertkov O Lucas S Copeland A Glavina Del Rio T Nolan M Tice H Cheng JF Han C Brambilla E Pitluck S Liolios K Ivanova N Mavromatis K Mikhailova N Pati A Bruce D Detter C Tapia R Goodwin L Chen A Palaniappan K Land M Hauser L Chang YJ Jeffries CD Rohde M Göker M Spring S Woyke T Bristow J Eisen JA Markowitz V Hugenholtz P Kyrpides NC Klenk HP 《Standards in genomic sciences》2010,2(1):57-65
Veillonella parvula (Veillon and Zuber 1898) Prévot 1933 is the type species of the genus Veillonella in the family Veillonellaceae within the order Clostridiales. The species V. parvula is of interest because it is frequently isolated from dental plaque in the human oral cavity and can cause opportunistic infections. The species is strictly anaerobic and grows as small cocci which usually occur in pairs. Veillonellae are characterized by their unusual metabolism which is centered on the activity of the enzyme methylmalonyl-CoA decarboxylase. Strain Te3(T), the type strain of the species, was isolated from the human intestinal tract. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the large clostridial family Veillonellaceae, and the 2,132,142 bp long single replicon genome with its 1,859 protein-coding and 61 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project. 相似文献
18.
19.
为了探讨顶坛花椒(Zanthoxylum planispimum var. dintanensis)衰老退化的原因,实现林分稳定与可持续性经营,该文以开黄花为典型标志的衰老退化植株和正常生长的植株为研究对象,采用土壤农业化学和环境矿物学的方法,分析不同植株根区土壤矿质元素含量,评价土壤综合质量。结果表明:(1)正常生长植株根区土壤的C、P、K、S、Se、Sr、Mo、氧化物等总体水平显著高于衰老退化植株,总氮、速效磷、速效氮、Cu、Pb、Zn、Cr无显著差异,其他元素的变化规律不明显。元素的有效态含量亦对植株生长产生影响。从植物营养需求角度看,大量、中量、微量元素均对土壤质量产生支配效应。(2)根区土壤质量指数表现为正常生长植株3最高、衰老退化植株1最低,说明土壤质量对顶坛花椒衰老退化具有影响。(3)顶坛花椒林分经营时,应培育良好的土壤结构,注重土壤养分的全面性和均衡性,关注矿质元素过低引起的亏缺效应。 相似文献
20.
The «living floors of the Acheulean huntersof Terra Amata are situated in their stratigraphical framework; they are included in a beach ridge and in a dune ascribed to the Mindelian glaciation and followed by a substantial paleosol ascribed to the Mindel-Riss interglacial. Palynological studies made in the deposits of the Middle Pleistocene show a rather great rate of forest-trees. The relative importance of trees growing in cool and wet areas and of thermophilous or typically mediterranean species, in every layers, allows to indicate a succession of climatic oscillations inside of a long and rather mild period. Among large mammals, the absence of any archaic form and of any recently appeared form, does not make it possible neither to confirm nor to exclude the hypothesis of a «Mindelian age for this fauna. The faunistic assemblage likewise corresponds to a temperate climate and a forest environment. 相似文献