Xem 1-20 trên 39 kết quả Abiotic factors
  • Growth and productivity of higher plants are adversely affected by various environmental stresses which are of two main types, biotic and abiotic, depending on the source of stress. Broad range of abiotic stresses includes osmotic stress caused by drought, salinity, high or low temperatures, freezing, or flooding, as well as ionic, nutrient, or metal stresses, and others caused by mechanical factors, light, or radiation.

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  • Forests play a major role in global carbon (C) cycle, and the carbon density (CD) could reflect its ecological function of C sequestration. Study on the CD of different forest types on a community scale is crucial to characterize in depth the capacity of forest C sequestration.

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  • To investigate delays in the diagnosis and treatment of inpatients with smear-positive pulmonary tuberculosis and to identify factors affecting these delays. Materials/Methods: 204 hospitalized patients with smear-positive pulmonary tuberculosis were identified. The clinical files of the patients were analyzed and questionnaires were created. Results: Mean application interval was 31.4 days, mean referral interval was 22.1 days, mean diagnosis interval was 3.3 days, and mean initiation of treatment interval was 1.4 days. Patient delay was present in 34.8 percent of the patients.

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  • Plants are continuously affected by a variety of environmental factors. Whereas biotic environmental factors are other organisms such as symbionts, parasites, pathogens, herbivores, and competitors, abiotic factors include parameters and resources which determine plant growth like temperature, relative humidity, light, availability of water, mineral nutrients, and CO 2 , as well as wind, ionizing radiation, or pollutants (Schulze et al. 2002 ) . The effect each abiotic factor has on the plant depends on its quantity or intensity.

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  • Permanganate may be applied to sites as either potassium permanganate (KMnO4) or sodium permanganate (NaMnO4). Where cost dominates over engineering factors at a site, potassium permanganate is the preferred chemical form because it is more widely available, less costly, and is available in solid form, which facilitates transport and handling. Where other factors are more important, the liquid form of sodium permangante is preferable.

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  • Metabolism of pesticides denotes that any foreign substance that enters in the living system and how it will be changed into non-toxic and thrown out due to the enzymatic activity and other mode of action. When chemical toxins applied to nonliving substance (soil and water) that will lose the toxic principles by degradation process due to the action of biotic and abiotic factors. The time to nullify the toxicity is of prime importance and it vary depending upon the chemical molecule and environmental conditions.

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  • Over the past decade, our understanding of plant adaptation to environmental stress, including both constitutive and inducible determinants, has grown con- siderably. This book focuses on stress caused by the inanimate components of the environment associated with climatic, edaphic and physiographic factors that substantially limit plant growth and survival. Categorically these are abiotic stresses, which include drought, salinity, non-optimal temperatures and poor soil nutrition.

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  • Does this mean that differences in genetic diversity levels will have predictable ecological consequences? The answer is no, because only one portion of genetic diversity is connected to ecological factors, i.e. adaptation. Ecological adaptation is a significant factor for example, in range expansion of plant species. Plants with different genotypes conferring the highest levels of fitness are expected to survive and reproduce better, shifting the gene pool over time towards higher frequencies of the alleles making up the more successful genotypes (Ward et al., 2008).

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  • The same amount of water has been present on our planet for about 4 billion years, since shortly after the Earth was formed. Since then it has cycled through evaporation, condensation, precipitation and surface runoff multiple times. Water scarcity as an abiotic factor ranging from moderate to severe stress levels, accompanied by loss of moisture in the soil, is extremely hard for most organisms to cope with, particularly terrestrial plants and their food-chain dependents.

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  • While most consumers still base their travel decisions largely on price, value for money, service and availability, more and more people are taking environmental factors into account. The railway community is therefore working hard to provide customers with comprehensive information on climate change, air pollution and the ‘external costs’ of transport. New internet-based tools, such as EcoPassenger and EcoTransIT (see Figure 6), are making a range of data available to customers.

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  • IN BOTH NATURAL AND AGRICULTURAL CONDITIONS, plants are frequently exposed to environmental stresses. Some environmental factors, such as air temperature, can become stressful in just a few minutes; others, such as soil water content, may take days to weeks, and factors such as soil mineral deficiencies can take months to become stressful. It has been estimated that because of stress resulting from climatic and soil conditions (abiotic factors) that are suboptimal, the yield of field-grown crops in the United States is only 22% of the genetic potential yield (Boyer 1982).

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  • 22 The Abiotic Environment 1. Introduction The development and reproduction of insects are greatly influenced by a variety of abiotic factors. These factors may exert their effects on insects either directly or indirectly (through their effects on other organisms) and in the short- or long-term.

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  • In a book titled Photosynthesis it is easy to forget that light is not simply the energy driving plant metabolism. Light also is the central environmental factor that affects plant size, shape and development. In fact, light activation of photomorphogenic signaling pathways sets the stage for photosynthesis and ensures the maintenance of the apparatus. The effects of specific wavebands of light exert their influence on plant biology from the molecular level all the way up to the higher morphological level, and even contribute to the canopy form as a whole.

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  • Canadian GAAP requires the use of bid prices for long positions and ask prices for short positions in the fair valuation of investments traded in an active market, rather than the use of closing prices currently used for the purpose of determining Net Asset Value (“NAV”). For investments that are not traded in an active market, Canadian GAAP requires the use of valuation techniques, incorporating factors that market participants would consider in setting a price.

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  • Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress

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  • We approximate credit risk developments at the bank level by considering non- performing loans of each institution and rating changes at the individual security level. Importantly, our database allows us to identify not only the rating of these securities at the time of origination but also their evolution over time. We also analyze to what extent housing prices, securitization activity and lending may have asymmetric effects across institutions and geographically (at the regional level) by identifying the role of each of these factors.

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  • A popular approach to measuring the interest-rate risk exposure of a bank is to run regressions of the bank’s stock return on a risk factor, such as an interest rate. The regression coefficient on the interest rate — often referred to as the interest-rate beta, is a measure of the bank’s average exposure to interest rate changes over the sample period considered (Flannery and James 1984a). Interest rate betas do not tell us where the bank’s exposure comes from, that is, what positions generate it.

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  • This paper lays out the key considerations underlying the choice between branch and subsidiary structure for cross-border banking groups and their home and host countries. It examines the relative advantages of different organizational structures for cross-border banking groups and discusses the issues for financial stability from home and host country perspectives.

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  • Science is occurring all around you, and the opening photo of each chapter will preview the science you will be learning about. The Chapter Preview will give you an idea of what you will be learning about, and you can try the Launch Lab to help get your brain headed in the right direction. The Foldables exercise is a fun way to keep you organized.

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  • Since the early 1970s, a variety of issues relating to energy supply have disrupted the energy marketplace. The oil crises of the 1970s, the deregulation of electricity and gas markets, the ebb and flow of various conflicts in the Middle East, Y2K fears, air-quality concerns, the recognition of global warming, and California’s recent energy supply woes are just some of the events and concerns that have affected both consumer perceptions and market prices.

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