Flow injection analysis of environmental samples for nitrate using an ion-selective electrode.
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Autoanalysis↗
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Results for “Environmental selection”
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Responses to long-term divergent selection for eight-week body weight in chickens.
Thirty-six generations of divergent selection for body weight at 8 wk of age resulted in approximately an eightfold difference between the high (HWS) and low (LWS) lines for this trait. In both White Plymouth Rock lines, selection intensities declined over generations, with responses about five times greater during the first 18 than the last 18 generations of selection in Line HWS and about two times greater in Line LWS. Also, responses to selection were more irregular in the later than in earlier generations. Sexual dimorphism of body weight (male:female) was greater for Line LWS than HWS. A randombred control line (AC) maintained concurrently with the selected lines did not exhibit environmental trends across generations. Relaxed lines, established at different generations of selection, were used to evaluate effectiveness of selection and monitor environmental changes over short periods.
Animals↗
Environmental whole farm management plans: their character, diversity, and use as agri-environmental indicators in New Zealand.
This paper reports on a nationwide survey of environmental farm plan programmes and plan characteristics, towards determining New Zealand's (NZ's) capability and eligibility for reporting on the Organisation for Economic Cooperation and Development's (OECD) environmental whole farm management plan agri-environmental indicator. Considerations regarding the validity of the indicator are discussed. Environmental farm planning in NZ is widespread, fragmented, and diverse. Nine of NZ's 16 regional authorities have environmental farm plan programmes involving 20 different types of environmental farm plans. Potentially half of NZ's total area of farmland is included, but this is reduced by limited and selective use of environmental farm plans as policy instruments. Three authorities are capable of readily reporting the number and coverage of their environmental farm plans; six would need to manually compile the information. Compliance monitoring is mostly informal, but necessary for checking the implementation of plan works and actions. Eligibility of NZ environmental farm plans cannot be determined until the OECD define acceptance standards. A contemporary definition of environmental farm plans is proposed, along with additional criteria necessary to ensure such plans are credible indicators of issue ownership, adoption of best management practice, and landscape changes intended to improve environmental quality.
Agriculture↗
Character process model for semen volume in AI rams: evaluation of correlation structures for long and short-term environmental effects.
The objective of this study was to build a character process model taking into account serial correlations for the analysis of repeated measurements of semen volume in AI rams. For each ram, measurements were repeated within and across years. Therefore, we considered a model including three environmental effects: the long-term environmental effect, which is a random year(*)subject effect, the short-term environmental effect, which is a random within year subject(*)collection effect, and the classical measurement error. We used a four-step approach to build the model. The first step explored graphically the serial correlations. The second step compared four models with different correlation structures for the short-term environmental effect. We selected fixed effects in the third step. In the fourth step, we compared four correlation structures for the long-term environmental effect. The model, which fitted best the data, used a spatial power correlation structure for the short-term environmental effect and a first order autoregressive process for the long-term environmental effect. The heritability estimate was 0.27 (0.04), the within year repeatability decreased from 0.56 to 0.44 and the repeatability across years decreased from 0.43 to 0.37.
Animals↗
Effect of Plant Species and Environmental Conditions on Ice Nucleation Activity of Pseudomonas syringae on Leaves.
Selected plant species and environmental conditions were investigated for their influences on expression of ice nucleation activity by 15 Pseudomonas syringae strains grown on plants in constant-temperature growth chamber studies. Ice nucleation frequencies (INFs), the fraction of cells that expressed ice nucleation at -5 or -9 degrees C, of individual strains varied greatly, both on plants and in culture. This suggests that the probability of frost injury, which is proportional to the number of ice nuclei on leaf surfaces, is strongly determined by the particular bacterial strains that are present on a leaf surface. The INFs of strains were generally higher when they were grown on plants than when they were grown in culture. In addition, INFs in culture did not correlate closely with INFs on plants, suggesting that frost injury prediction should be based on INF measurements of cells grown on plants rather than in culture. The relative INFs of individual strains varied with plant host and environment. However, none of seven plant species tested optimized the INFs of all 15 strains. Similarly, incubation for 48 h at near 100% relative humidity with short photoperiods did not always decrease the INF when compared with a 72 h, 40% relative humidity, long-photoperiod incubation. Pathogenic strains on susceptible hosts were not associated with higher or lower INFs relative to their INFs on nonsusceptible plant species. The ice nucleation activity of individual bacterial strains on plants therefore appears to be controlled by complex and interacting factors such as strain genotype, environment, and host plant species.
Journal Article↗
Emerging public health issues in Alaska: occupational and environmental health.
The principal purpose of this article is to examine selected Alaskan occupational and environmental health problems and associated issues. Specifically, we focus on two traditional areas of interest in occupational and environmental health: 1) Job-related injuries, illnesses, and fatalities, and 2) accidental spills and uncontrolled waste sites involving hazardous materials. In 1986 the Alaska Department of Labor reported 13,154 recordable occupational injuries and illnesses among workers in the private sector. The injury rate for private sector workers was 10.2 cases per 100, compared to a rate of 7.9 for the U.S. private sector as a whole. There are approximately 550 known hazardous waste sites in Alaska identified by military, other federal, or state sources. One study documents 1,330 hazardous materials incidents in Alaska during a one year period. Effective public health policy for these occupational and environmental health hazards requires the development of an adequate database and a specific plan of action for the future.
Accidents, Occupational↗
The cystic fibrosis heterozygote--advantage in surviving cholera?
Cystic fibrosis (CF) is the most common fatal genetic disorder of caucasians. While it has been hypothesized that there is a CF heterozygote advantage which allowed the gene to achieve such high prevalence, the nature of that advantage remains a mystery. The recent identification and sequencing of the CF gene has increased the probability that the CF heterozygote advantage will be discovered. In this hypothesis we review the information which is known about the selection of the CF mutation and its cellular consequences, and present evidence which suggests that resistance to cholera may have been the environmental factor which selected CF heterozygotes over their 'normal' homozygote cohort. Future lines of experimentation and possible clinical applicability to therapy of secretory diarrhea are presented.
Chloride Channels↗
Health impacts of environmental mycobacteria.
Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are complex and likely much broader than currently recognized. Environmental mycobacteria preferentially survive chlorination in municipal water, using it as a vector to infect humans. Widespread chlorination of water has likely selected more resistant environmental mycobacteria species and potentially explains the shift from M. scrofulaceum to M. avium as a cause of cervical lymphadenitis in children. Thus, human activities have affected mycobacterial ecology. While the slow growth and hydrophobicity of environmental mycobacteria appear to be disadvantages, the unique cell wall architecture also grants high biocide and antibiotic resistance, while hydrophobicity facilitates nutrient acquisition, biofilm formation, and spread by aerosolization. The remarkable stress tolerance of environmental mycobacteria is the major reason they are human pathogens. Environmental mycobacteria invade protozoans, exhibiting parasitic and symbiotic relationships. The molecular mechanisms of mycobacterial intracellular pathogenesis in animals likely evolved from similar mechanisms facilitating survival in protozoans. In addition to outright infection, environmental mycobacteria may also play a role in chronic bowl diseases, allergies, immunity to other pulmonary infections, and the efficacy of bacillus Calmette-Guerin vaccination.
Animals↗
Aggression from a developmental perspective: genes, environments and interactions.
Genetic influences on the social behaviours of non-human mammals are ubiquitous, powerful and readily detected. But demonstrations that social behaviours are influenced by genes constitute only part of the story. Developmental findings have helped complete the picture. Specifically, these studies show that: (1) genetic effects for aggressive behaviours are highly malleable over the course of development; (2) genetic influences on aggressive behaviour are more dynamic, easily achieved and open to rapid manipulation than has been recognized in current models of social evolution and behavioural genetics; (3) developmental timing has a significant impact upon the nature of the genetic effects observed in aggressive behaviours. These empirical results are consistent with the view that social behaviours are among the first features to be influenced by genetic selection and by environmental experience. Social actions have distinctive properties in adaptation because they organize the space between the organism and the environment and promote rapid, selective and novel accommodations. The modern integrative view of the development of individual-in-context brings attention to the correlation between constraints within and external to individuals. This paper reviews findings on how these processes become integrated over time in individuals and species, and their implications for the nurture of nature.
Aggression↗
Development of the aggregation model of adverse environmental and health effects for evaluation of large areas of ecological hazard.
The model of aggregation of 12 parameters describing the environmental and health effects in areas of ecological hazard has been elaborated. The values of particular indices create the characteristic profile useful for selection of dominant environmental problems. The general index of hazard is suitable for establishing priorities among ecological hazard areas.
Environmental Health↗
Genetic trend and environmental effects in a population of cattle selected for twinning.
A selection experiment was established in 1981 to increase twinning rate in cattle. Results reported are through 1993 calf crops. Estimates of genetic parameters for a two-trait twinning and ovulation rate model with genetic groups were as follows: heritabilities of .03 for twinning and .07 for ovulation rates with a genetic correlation of nearly 1.00 and fractional permanent environmental variances of .06 for twinning and .05 for ovulation rate. Corresponding estimates when group effects were ignored were as follows: heritabilities of .08 and .08 and fractional permanent environmental variances of .02 and .04 for twinning and ovulation rates, respectively. Twinning rate (percentage) in the project at the U.S. Meat Animal Research Center has increased in all cows born in the project by year of calving from 3.4% in 1982 to 28.5% in 1993, a phenotypic increase of 25.1%. The estimated genetic change in twinning of cows by year of calving using the groups model has been 15.2%. The increase in average genetic value by year of birth has been 18.2% in twinning and 15.0% in ovulation rate from 1980 through 1991. Solutions for seven selected groups of foundation animals ranged from -6.0 to 33.1% and influenced genetic trend.
Aging↗
Monitoring program of biological status of human populations related to environmental changes.
The paper aims at a synthesis of research carried out hitherto which might serve to evaluate the diagnostic value of human biological traits related to natural, economic and socio-cultural properties of the environment. The development of a monitoring program is the object of research of the Department of Human Ecology, the Polish Academy of Sciences, in the years 1986-1990 in Poland, and also of recommendations of the IUAES Human Ecology Commission for the last decade of the 20th century in various countries over the world. Generally, the stages of ontogenesis that are appropriate for monitoring are those which involve an intense proliferation of cells and a rapid growth. The appropriate subjects are the more ecosensitive individuals, that is the heterozygous ones as well as men. The more ecosensitive traits are those developed after birth in over 50 per cent of their adult value. Traits of the highest diagnostic (discriminant) value with respect to environmental conditions were selected. The results are based on the analysis of: 35 somatic traits in 1034 newborns from Białystok and Zambrów in relation to the traits of their families and parents; 21 somatic traits in 2461 of 11 year-old children from Lublin; 40 somatic, physiological and psychomotor traits in 1186 children, 6-19 years old from Poland; 26 morphological and physiological traits in 4771 subjects of 5-90 years of age in Poland; 9 somatic and 17 motor traits in 127,489 children, 7-19 years old, in relation to economic and demographic conditions in 98 regions of Poland; and 27 somatic, physiological and psychomotor traits in children and their parents from the ages of 3-80 years, from 3995 families from Poland. The age particularly important to the study includes: foetal growth effects recorded as newborn status, child development from about half a year (since weaning) to about 3 years of age, development at the early period of puberty, the period at adolescence, age at the peak value (maximal size, best results) of the main morphological and functional traits (usually between the age of 12 and 30), and finally, the rate of involution of these main traits in older age. For the "minimum program" (for public health and environmental conservation services) among somatic traits, 3 were selected for a minimum program: stature, Kaup index, and cephalic index. Among physiological traits, 2 were selected: forced respiratory volume per second and hemoglobin concentration. Among motor traits, 3 were selected for the minimum program: distant movement accuracy, grip strength, and standing long jump.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
Natural selection and population dynamics.
To what extent, and under which circumstances, are population dynamics influenced by concurrent natural selection? Density dependence and environmental stochasticity are generally expected to subsume any selective modulation of population growth rate, but theoretical considerations point to conditions under which selection can have an appreciable impact on population dynamics. By contrast, empirical research has barely scratched the surface of this fundamental question in population biology. Here, we present a diverse body of mostly empirical evidence that demonstrates how selection can influence population dynamics, including studies of small populations, metapopulations, cyclical populations and host-pathogen interactions. We also discuss the utility, in this context, of inferences from molecular genetic data, placing them within the broader framework of quantitative genetics and life-history evolution.
Adaptation, Biological↗
The origin and maintenance of virulence for the human pathogenic fungus Cryptococcus neoformans.
The origin of virulence in environmental fungi that have no requirement for animal hosts in their life cycle is enigmatic. Cryptococcus neoformans is a human pathogenic fungus with virulence factors for mammalian pathogenesis that also contribute to environmental survival. C. neoformans virulence may originate from selection pressures imposed by environmental predators.
Cryptococcosis↗
Directing the outcome of deoxyribozyme selections to favor native 3'-5' RNA ligation.
Previous experiments have identified numerous RNA ligase deoxyribozymes, each of which can synthesize either 2',5'-branched RNA, linear 2'-5'-linked RNA, or linear 3'-5'-linked RNA. These products may be formed by reaction of a 2'-hydroxyl or 3'-hydroxyl of one RNA substrate with the 5'-triphosphate of a second RNA substrate. Here the inherent propensities for nucleophilic reactivity of specific hydroxyl groups were assessed using RNA substrates related to the natural sequences of spliceosome substrates and group II introns. With the spliceosome substrates, nearly half of the selected deoxyribozymes mediate a ligation reaction involving the natural branch-point adenosine as the nucleophile. In contrast, mostly linear RNA is obtained with the group II intron substrates. Because the two sets of substrates differ at only three nucleotides, we conclude that the location of the newly created ligation junction in DNA-catalyzed branch formation depends sensitively on the RNA substrate sequences. During the experiment that led primarily to branched RNA, we abruptly altered the selection strategy to demand that the deoxyribozymes create linear 3'-5' linkages by introducing an additional selection step involving the 3'-5'-selective 8-17 deoxyribozyme. Although no 3'-5' linkages (<or=1%) were detectable in the pool products at the point that the 3'-5' selection pressure was applied, deoxyribozymes that specifically create 3'-5' linkages quickly emerged within a few selection rounds. Our success in obtaining 3'-5' linkages via this approach shows that the outcome of deoxyribozyme selection experiments can be dramatically redirected by strategic changes in the selection procedure, even at a late stage. These results relate to natural selection, in which abrupt environmental variation can provide a rapid change in selection pressure. Linear 3'-5' RNA linkages are an important practical objective because the native backbone is desirable in site-specifically modified ribozymes assembled by ligation. Therefore, this new approach to obtain 3'-5'-selective RNA ligase deoxyribozymes is particularly important for ongoing selection efforts.
Base Sequence↗
The effect of divergent selection for total plasma phosphorus in Japanese quail on fearfulness and selected blood and heart parameters.
A selection experiment utilizing Japanese quail was initiated to study the genetic relationship of growth and reproduction traits. In this study, lines were selected for increased (HP line) and decreased (LP line) total plasma phosphorus at the beginning of lay. The HP and LP lines were derived from a randombred control population (R1 line) that was maintained with the selected lines to remove environmental variation over generations. During the course of selection, it was observed that blood from HP line females was more viscous than that of the LP and R1 females. In later generations of selection, mortality of females during a 120-d egg production period was higher in the HP line than in the LP and R1 lines. The purpose of this experiment was to identify possible factors contributing to the increased mortality in the HP line. Fearfulness, as measured by tonic immobility, was greater in the HP and LP lines than in the R1 line. Indirect blood pressure measurements were made near the beginning and near the end of the 120-d egg production period. No significant line differences were observed in either measurement. Weight of the heart at the end of the laying period was higher in the HP and LP lines than in the R1 line. Histological study of the hearts of the HP and R1 lines indicated significant increases in the HP line in collagen content of the coronary arteries and in myocardial fibrosis. The data suggest that the increased mortality of females of the HP line relative to the R1 line during the laying period may be related to increased fearfulness and changes in the coronary structure leading to heart abnormalities.
Animals↗
Paternal half-sib heritabilities and genetic, environmental, and phenotypic correlation estimates from randomly selected Hereford cattle.
Growth and carcass data were collected during 10 yr at the Fort Keogh Livestock and Range Research Laboratory in Miles City, MT from a Hereford herd selected at random. The objective was to compare genetic parameter estimates from this randomly selected herd with estimates from published selection studies. Only bulls were included in the data set. Bulls were slaughtered between 14 and 17 mo of age. Genetic parameters were estimated by the paternal half-sib procedure. Data were subdivided into three subgroups: 1) all bulls that had birth weights, 2) bulls with complete records for growth traits, and 3) bulls with complete carcass and growth records. The heritability estimate for birth weight on 736 progeny from 86 sires was .18. The second group included 616 progeny representing 85 sires and heritability estimates were weaning weight, .17; daily gain from birth to weaning, .20; final test weight, .42; and daily gain on test, .47. The third group included 401 progeny from 75 sires and heritability estimates were carcass weight, .38; longissimus muscle area, .51; marbling, .31; slaughter weight, .42; and dressing percentage, .25. Thus, these estimates of heritability were in quite good agreement with previously published values, with a tendency for these estimates to be lower for early growth weights. Phenotypic and environmental correlations were in good agreement and genetic correlations were in general agreement with the data reviewed. Estimates of heritabilities from this herd selected at random were not larger than previous estimates from selected herds.
Adipose Tissue↗
Indicator-based assessment of environmental hazards and health effects in the industrial cities of upper Silesia, Poland.
Using an indicator-based approach, we assessed environmental hazards and related health effects in populations of industrial cities with more than 100,000 inhabitants in Upper Silesia, Poland, and analyzed the relationship between environment and health. We adopted the method developed by Dutkiewicz et al. for assessing large geographic areas. Based on routinely collected environmental and health data, two groups of indicators, environmental indicators (EIs) and health status indicators (HSIs), related to environmental contamination were selected. The EI and HSI values were normalized and aggregated into synthetic measures using Strahl's taxonometric method. The synthetic measures indicated the intensity of environmental hazards and health outcomes. We used a three-level index scale to compare and rank the cities under the study and, consequently, to facilitate decision making. Findings of the assessment identified cities where actions aimed at reducing environmental hazards and improving population health status should be established as priorities. These cities included Chorzów, Katowice, Sosnowiec, Bytom, and Zabrze. We found a high correlation between the synthetic measures of environmental indicators and the synthetic measure of health status indicators (r = 0.77), as well as a high level of consistency between environmental hazard indices and environmental-related health status indices (73%). This may indicate the existence of a causal relationship between the environmental contamination within industrial cities and the health status of their inhabitants.
Adolescent↗