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At least 577 records · Page 32Linked to original sources

PubMed1986

Altered synaptic transmission in dentate gyrus of rats reared in complex environments: evidence from hippocampal slices maintained in vitro.

Pre- and postsynaptic responses to activation of medial perforant path (MPP) axons were examined in hippocampal slices taken from rats reared for 3-4 wk in relatively complex (EC) or individual cage (IC) environments. Three types of extracellular field potentials were recorded in the infrapyramidal blade of the dentate gyrus: 1) granule cell population spikes (PSs), which reflect the number and synchrony of discharging granule cells (2), 2) population excitatory postsynaptic potentials (EPSPs), which reflect the amount of excitatory synaptic current flow into dendrites (28), and 3) presynaptic fiber volleys (FVs), which reflect the number of activated axons (28). Stimulation of the MPP evoked significantly larger PSs in slices taken from EC rats. There was no significant effect of rearing environment on PS/EPSP relationships. The slopes of EPSPs recorded at the site of synaptic activation in the dentate molecular layer and at the major current source in the dentate granule cell layer were significantly greater in slices taken from EC rats. The presynaptic FV was recorded at the site of synaptic activation in the molecular layer. FV amplitude did not differ significantly as a function of rearing environment. To examine possible differences in tissue impedance, granule cells were activated by stimulating granule cell axons in the dentate hilus and recording the antidromic PS in the granule cell layer. Antidromic PS amplitude was not significantly affected by rearing environment. The relative permanence of the experience-dependent alterations in synaptic transmission was assessed by comparing slices taken from rats that had been reared for 4 wk in complex environments followed by 3-4 wk in individual cages with those from rats reared for 7-8 wk in individual cages. There were no significant differences in MPP synaptic transmission between these groups of animals. The results suggest that experience in a relatively complex environment is associated with greater MPP synaptic transmission arising from an increased synaptic input to granule cells; the greater MPP synaptic transmission associated with behavioral experience can occur independent of behavioral state, influences from extrahippocampal brain regions and intrahippocampal inhibitory activity; and the experience-dependent synaptic alterations in the dentate gyrus are transient, in contrast to experience-dependent morphological alterations described in occipital cortex. The possible relationship of these alterations to the phenomenon of long-term enhancement is discussed.

Afferent Pathways↗

PubMedDate not supplied

A low calcium environment enhances AP-1 transcription factor-mediated gene expression in the development of osteoblastic MC3T3-E1 cells.

Animals fed a low calcium diet develop hypocalcemia and osteoporotic bone. Earlier we conjectured that a low calcium environment might be one of the factors causing abnormalities in hard tissues. Osteoblastic MC3T3-E1 cells (E1 cells) undergo a process of proliferation and differentiation and then produce small mineralized nodules. In this study, we examined the effects of a low calcium environment on osteoblast-like cells cultured with 10% fetal bovine serum and ascorbic acid. Under the culture condition, nodules with characteristics of normal bone appeared by day 30 regardless of the calcium conditions. However, the low calcium environment enhanced the mRNA expressions of c-fos, c-jun and osteocalcin, a specific marker of the osteoblast phenotype. And the exposure to the low calcium medium inhibited the formation of bone nodules. We further studied the differential expressions of c-fos and c-jun in relation to their responses to serum as a function of phenotypic development in the low calcium environment. Both c-fos and c-jun expressions were highly activated by treatment with epidermal growth factor (EGF), but the magnitude of activation was significantly larger under the low calcium condition than the normal condition at each stage. In addition, DNA-binding activities of activating protein-1 (AP-1), Fos/Jun family dimers, were also accelerated by EGF treatment in the low calcium environment. Our findings suggested that osteocalcin, a bone formation marker, c-fos and c-jun genes, and family protein products (AP-1) interacted to restore the normal cell function which deteriorated in the low calcium environment.

Alkaline Phosphatase↗

PubMed1995

Evolving mobile robots in simulated and real environments.

The problem of the validity of simulation is particularly relevant for methodologies that use machine learning techniques to develop control systems for autonomous robots, as, for instance, the artificial life approach known as evolutionary robotics. In fact, although it has been demonstrated that training or evolving robots in real environments is possible, the number of trials needed to test the system discourages the use of physical robots during the training period. By evolving neural controllers for a Khepera robot in computer simulations and then transferring the agents obtained to the real environment we show that (a) an accurate model of a particular robot-environment dynamics can be built by sampling the real world through the sensors and the actuators of the robot; (b) the performance gap between the obtained behaviors in simulated and real environments may be significantly reduced by introducing a "conservative" form of noise; (c) if a decrease in performance is observed when the system is transferred to a real environment, successful and robust results can be obtained by continuing the evolutionary process in the real environment for a few generations.

Algorithms↗

PubMed1975

Exposure to halogenated hydrocarbons in the indoor environment.

The indoor environment has frequently been ignored as a significant source of exposure to air pollutants. To date there are a number of documented examples of levels of indoor air pollutants greatly exceeding those levels which commonly occur in the outdoor environment. Among these instances are airborne buildup of polynuclear aromatics and cadmium from cigarette smoke, lead from burning candles, and vinyl chloride from use of aerosols containing this substance as a propellant. These examples suggest that there may be additional sources of indoor air pollutants, particularly halogenated hydrocarbons from aerosol products, which have heretofore not been generally recognized as important. The present paper endeavors to review those instances where halogenated hydrocarbons in the indoor air environment may build up to concentrations of potential public health concern. These considerations may be especially relevant in future years as increasing efforts are being made to insulate buildings more efficiently as a means to conserve energy. The available data strongly suggest that halogenated hydrocarbons are an important class of air pollutants in the indoor environment and that their presence in the outdoor environment should also be carefully examined. In this regard, halogenated hydrocarbons in the outdoor environment may also contaminate indoor air spaces.

Aerosol Propellants↗

PubMedDate not supplied

Managing and maintaining a safe environment in the hospital setting.

On entering hospital, patients and visitors assume that they are in a safe environment. Maintaining a safe environment in hospitals depends on not only the infrastructure, but also the equipment and materials that are used on the premises. Complaints about hospitals often include comments on the environment, its lack of cleanliness, poor food and the general look of debilitation. Key legislation for managing a safe environment is the Health and Safety at Work Act 1974. Complementary guidance includes the Control of Substances Hazardous to Health Regulations 1999 and the Environmental Protection Act 1990. The Incorporation of such legislation into local policies and guidelines ensures that healthcare staff can set standards to maintain the integrity of the patient's environment. This article will consider aspects of hospital life involved in maintaining a safe environment.

Food Service, Hospital↗

PubMed2006

Changing the work environment in ICUs to achieve patient-focused care: the time has come.

The American Association of Critical-Care Nurses (AACN) Standards for Establishing and Sustaining Healthy Work Environments and the American College of Chest Physicians (ACCP) Patient-Focused Care Project are complementary initiatives that provide a road map for creating practice environments where interdisciplinary, patient-focused care can thrive. Healthy work environments are so influential that failure to address the issue would result in deleterious effects for every aspect of acute care and critical care practice. Skilled communication and true collaboration are crucial for transforming work environments. The ACCP project on patient-focused care was born out of a realization that medicine as currently practiced is too fragmented, too focused on turf battles that hinder communication, and too divorced from a real understanding of what patients expect and need from their health-care providers. Communication as well as continuity and concordance with the patients' wishes are the foundational premises of care that is patient-focused and safe. Some individuals may achieve some level of genuine patient-focused care even when they practice in a toxic work environment because they are gifted communicators who embrace true collaboration. At best, those efforts will most likely be hit-or-miss, and such heroism will be impossible to sustain if the environment is not transformed into a model that reflects the standards and initiatives set out by the AACN and the ACCP. Other innovative models of care delivery remain unreported. The successes and failures of these models should be shared with the professional community.

Communication↗

PubMedDate not supplied

Cell movement and symmetry of the cellular environment.

The movement of micro-organisms was investigated in different cellular environments. The type of movement was described in terms of the symmetry of the cellular environment: (i) Random movement - isotropic symmetry of the environment, (ii) contact guidance - apolar symmetry of the environment and (iii) directed movement as chemotaxis and galvanotaxis - polar symmetry of the environment. To quantitate cell movement it was necessary to parameterize the environment as well as the cell movement by observables. The random movement was quantitated by the diffusion coefficient. The contact guidance of the nematic type and the contact guidance on a bent surface were quantified by an apolar order parameter. The contact guidance constant for fibroblast on a glass cylinder was 87.5 microns. The directed movement was quantified by a polar order parameter. Dose-response curves were derived and compared for different types of cells: Chemotaxis of granulocytes KCT-1 = 2.2 mm for 10 microM f-Met-Met-Met, galvanotaxis of granulocytes KG-1 = 0.2 V/mm, galvanotaxis of fibroblast KG-1 = 0.28 V/mm, galvanotaxis of spermatozoids of bracken fern KG-1 = 0.024 V/mm.

Cell Movement↗

PubMed2006

The influence of workplace environment on lung function of flour mill workers in Jalgaon urban center.

The workplace environment affects the health of workers. Unhygienic conditions are observed in the workplace environment of flour mills as fine organic flour dust gets airborne in the indoor environment of the flour mills. The present work was undertaken to study the health problems related to the workplace environment of flour mill workers. The results show that flour mill workers are receiving a heavy dose (average exposure concentration, 624 microg/m3) of flour dust. To determine the impact of flour dust on the lung function of the workers spirometric analysis was conducted. Significant declines in forced vital capacity (FVC), peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1) were observed in the flour mill workers as compared to expected values. This study reveals reduced lung efficiency of flour mill workers due to excessive exposure to fine organic dust prevalent in the workplace environment. The impairment in lung efficiency was increased with duration of exposure in the flour mill workers. The analysis of questionnaires used to generate information on self-reported problems reveals that most of the workers were suffering from asthma and respiratory problems. Furthermore, the data shows that 42% of the flour mill workers were having shortness of breath problems, 34% of workers were having frequent coughing, and 19% workers were having respiratory tract irritation. We recommend the compulsory use of personal protective equipment (nose mask) by flour mill workers during working hours. This would help to protect the workers health from the flour dust prevalent in the workplace environment. A regular periodic examination is necessary to measure the impact of particulate matter on the health of the flour mill workers.

Adult↗

PubMed1993

The Work Environment Board and the limits of social democracy in Canada.

A Work Environment Board was established to deal with all workplace health and safety issues within the Potash Corporation of Saskatchewan from 1978 to 1982. The Board was an experiment, established because of the observed deficiencies of the mandatory joint occupational health and safety committees that were legislated by the province in 1972. The administrators of the occupational health and safety program observed the problems faced by workers on these committees. An experiment was therefore established in one of the province's crown corporations that would transform the joint committee into a Work Environment Board with wider powers to deal with work environment matters within the corporation. In addition, a Work Environment Fund was established to enable the worker members on the Board to do their own research and to get the information they wanted. The Work Environment Board was frustrated by the fact that corporate leaders were not prepared to extend worker rights on the health and safety committees within the respective mines. Rather, they viewed health and safety reforms as part of an overall strategy of quality of work life. The social democratic government was not prepared to extend worker rights and to threaten management prerogatives. Now that there are three New Democratic Party (social democratic) governments in Canada, it appears that these governments are prepared to initiate technical improvements, but not the extension of worker rights in work environment matters.

Accidents, Occupational↗

PubMed1991

Effect of heterosis on performance of mice across three environments.

Performance of six genetic groups of mice was studied in three different environments in order to determine the effect of heterosis on consistency of performance in varied environments. Designed as a 3 x 6 factorial, data were analyzed using least squares analyses of variance. Genetic group effects, environmental effects, genetic group x environment interaction, and heterosis were examined for 42-d weight, age and weight at vaginal opening, age and weight at puberty, ovulation rate (determined by total corpora lutea), number of implantations, and number of fetuses at 10 d of gestation. Weight at vaginal opening, ovulation rate, implantation rate and total number of fetuses exhibited significant heterosis. Regression of these traits against an environmental index (mean performance of all genetic groups over environments) provided an estimate of stability of performance. In general, genetic groups exhibiting heterosis expressed more consistent performance across environments than pure lines did. We conclude that a stability model could be used to aid in identification of lines with consistent performance for production traits in variable environments.

Analysis of Variance↗

PubMed1988

Genetic parameter estimates for preweaning traits of beef cattle in a stressful environment.

Data collected from 1957 through 1985 from a Hereford herd located in the Southwest were analyzed separately for each sex to evaluate the heritabilities of and genetic correlations among preweaning growth traits within groups of environmentally similar years. Data were grouped into years with poor, moderate and good environments based on contemporary group means for male calves' weaning weight. A total of 7,690 records were analyzed for birth weight, weaning weight and preweaning daily gain with a model that included year of birth, sire within year of birth, age of dam and a covariate of day of birth for birth weight or age at weaning for the weaning traits. Year of birth was a significant source of variation in all environments for all traits, accounting for more of the variation in the good and poor years than in moderate years. Heritability estimates for all traits were greater in good and moderate years than in poor years for bull calves. For heifers, however, estimates for weaning weight and preweaning daily gain were greater in the poor environment. Genetic correlations among birth weight and preweaning gain increased from the good environment to the poor environment (-.49 +/- .26 to .82 +/- .56 for male calves and -.09 +/- 2.6 to .46 +/- .25 for female calves) but phenotypic correlations were near zero in all environments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Influence of host environment on growth of clonal CD5+B (Lyl+B) cells.

Autoimmune NZB mice have increased percentages of CD5+B (Lyl+B) cells in both the spleen and peritoneum. We have previously reported that as NZB mice age they develop a clonal population of hyperdiploid CD5+B cells in the spleen. These cells can readily be transplanted into unirradiated recipients. The growth characteristics of such transplanted hyperdiploid NZB spleen cells were examined in different recipient strains to determine if the immunological status of the host environments affected the growth of the clonal CD5+B cells. Young NZB and NZB.xid recipients (lacking hyperdiploid CD5+B cells) allowed growth and expansion of unpassaged CD5+B cells derived from primary NZB mice. Similarly, (NZBxDBA/2) and (NZBxBALB/c) F1 recipients allowed for expansion of CD5+B cell clones from primary sources. In a separate experiment, T cell-depleted NZB spleen cells containing a hyperdiploid CD5+B cell clone were transferred to SCID mice. The SCID environment supported the growth of the primary clone. None of these recipients normally have elevated CD5+B cells, yet these recipients allowed growth of primary transferred hyperdiploid cells. However, a difference in the ability of these recipient strains in their ability to expand multiply passaged CD5+B cell clones was observed. These results indicate that while hyperdiploid CD5+B cells are difficult to be maintained in culture, they can readily be passaged in vivo. The host environment may provide growth factors or signals for endogenous growth factors. Although the CD5+B clones arise initially in a hyperactive autoimmune environment, a hyperimmune environment is not necessary to support their growth. Transferred CD5+B cells affect the recipient environment and reduce the percentages of normal B cells.

Animals↗

PubMed1995

Divergent selection for growth in Japanese quail under split and complete nutritional environments. 8. Progress from generations 18 through 30 following change of selection criterion.

Following 17 generations of divergent selection for 4-wk BW under split- (SD) and complete- (CD) diet environments, two sublines were established from high (H-SD and H-CD) BW lines. Subline H-SDG derived from the H-SD line was selected for BW gain from 2 to 4 wk under the SD environment, whereas Subline H-CDG derived from the H-CD line was similarly selected under the CD environment. These two sublines were maintained and reproduced simultaneously with H-SD, L-SD, H-CD, L-CD lines from Generation 18 through 30. The purpose of changing the selection criterion was to investigate genetic variation in BW gain independent of changes that occur immediately following hatch. Selection progress and heritabilities (approximately .3) in BW lines (H-SD, H-CD, and L-SD) were similar from Generation 18 through 30. However, progress and heritability (approximately .1) was not as great in the L-CD line. These responses indicate that considerable additive genetic variation for 4-wk BW remains in these lines. Selection for increased BW gain from 2 to 4 wk in both sublines (H-SDG and H-CDG) resulted in smaller BW at 2 wk of age than did selection for 4-wk BW. Under the SD environment, H-SDG quail were smaller at 4 wk than H-SD quail following 12 generations of selection, whereas under the CD environment, H-CDG quail were larger than H-CD quail. Results indicate that selection for BW gain was more effective under the CD than SD environment and that the lack of improvement in 2-wk BW accompanying the increase in BW gain may adversely influence the potential benefits obtainable from selection for gain.

Animal Husbandry↗

PubMed2006

GIS and remote sensing applications in the assessment of change within a coastal environment in the Niger Delta region of Nigeria.

In the last decades, the Niger Delta region has experienced rapid growth in population and economic activity with enormous benefits to the adjacent states and the entire Nigerian society. As the region embarks upon an unprecedented phase of economic expansion in the 21st century, it faces several environmental challenges fuelled partly by the pressures caused by human activities such as oil and gas exploration, housing development, and road construction for transportation, economic development and demographic changes. This continued growth has resulted in environmental problems such as coastal wetland loss, habitat degradation, and water pollution, gas flaring, destruction of forest vegetation as well as a host of other issues. This underscores the urgent need to design new approaches for managing remote costal resources in sensitive tropical environments effectively in order to maintain a balance between coastal resource conservation and rapid economic development in developing countries for sustainability. Notwithstanding previous initiatives, there have not been any major efforts in the literature to undertake a remote sensing and GIS based assessment of the growing incidence of environmental change within coastal zone environments of the study area. This project is an attempt to fill that void in the literature by exploring the applications of GIS and remote sensing in a tropical coastal zone environment with emphasis on the environmental impacts of development in the Niger Delta region of Southern Nigeria. To deal with some of the aforementioned issues, several research questions that are of great relevance to the paper have been posed. The questions include, Have there been any changes in the coastal environment of the study area? What are the impacts of the changes? What forces are responsible for the changes? Has there been any major framework in place to deal with the changes? The prime objective of the paper is to provide a novel approach for assessing the state of coastal environments while the second objective seeks a contribution to the literature. The third objective is to provide a decision support tool for coastal resource managers in the assessment of environmental impacts of development in tropical areas. The fourth objective is to assess the extent of change in a tropical ecosystem with the latest advances in geo-spatial information technologies and methods. In terms of methodology, the paper draws from primary and census data sources analyzed with descriptive statistics, GIS techniques and remote sensing. The sections in the paper consist of a review of the major environmental effects and factors associated with the problem: initiatives and mitigation measures. The project offers some recommendations as part of the conservation strategies. In spite of concerted efforts by managers to address the problems, results revel that the study area experienced some significant changes in its coastal environments. These changes are attributed to socio-economic and environmental variables.

Demography↗

PubMed2003

Simultaneous spatial updating in nested environments.

When one moves, the spatial relationship between oneself and the entire world changes. Spatial updating refers to the cognitive process that computes these relationships as one moves. In two experiments, we tested whether spatial updating occurs automatically for multiple environments simultaneously. Participants turned relative to either a room or the surrounding campus buildings and then pointed to targets in both the environment in which they turned (updated environment) and the other environment (nonupdated environment). The participants automatically updated the room targets when they moved relative to the campus, but they did not update the campus targets when they moved relative to the room. Thus, automatic spatial updating depends on the nature of the environment. Implications for theories of spatial learning and the structure of human spatial representations are discussed.

Attention↗

PubMedDate not supplied

Laboratory information system test environment: validate upgrades, prevent disasters, and assist training.

A laboratory information system (LIS) test environment allows the laboratory to run and test programs without affecting the current production environment. This is essential for successfully introducing system enhancements and upgrades because it allows the LIS manager to uncover software errors before introducing them into the actual LIS system. A test environment is also a useful tool for training employees. In addition, a test environment enables laboratories to validate software before use in the live environment, which will probably be required by the Food and Drug Administration and the Health Care Financing Administration inspectors now that LISs are considered medical devices. This article examines the benefits, uses, and limitations of an LIS test environment; discusses the computer resources required; and explores the process of installing and validating a software release.

Clinical Laboratory Information Systems↗

PubMed1995

Telematics and protocols of care in critical care environments.

The paper discusses the potential roles for protocols of care within critical care environments from the perspective of providing real-time support for their application. The discussion is based around a conceptual model of care in critical care environments. This model has been developed in the wider context of developing information technology systems to support clinical care in critical care environments. The conceptual model of care is a three layer model which demonstrates both the hierarchical and temporal aspects of the care delivered to patients. It is proposed that if the value of protocols of care is to be realised in critical care environments then they must be seamlessly integrated into the routine data management associated with the care of patients. In order to demonstrate this and to evaluate the utility of this concept in the clinical environment, the systems from the AIM TANIT (Telematics in Anaesthesia and Intensive Therapy) project have been used as prototype platforms. The application of the concepts developed are described in two critical care environments: the anaesthesia department and the intensive care unit. Problems in using protocols of care in intensive care units suggest that integrating these with a problem solving methodology to create an integrated care plan may be a more appropriate approach to patient management.

Anesthesia Department, Hospital↗

PubMed1999

[An Internet-based "distance" learning for health, environment and sustainable development "distance learning without a frontier"].

Quality of the environment is crucial for human health. Environmental hazards may lead to adverse health effects, while a sound environment can support of enable health. It has been clear that health and environment must be understood within the context of social and economic development, which was stressed especially in the Earth Summit held in Rio de Janeiro, Brazil, in 1992. Investing in improvement of people's health and their environment is a prerequisite for sustainable development. The telecommunication revolution enables distance learning without frontiers in a reansparent and interactive environment. Applying the Internet and other telecommunication into public health including environmental health holds the greatest promise for global health. A wide application and access would facilitate and expedite the reduction of inequity prevailing between the south and north in an unprecedented speed. This proposed course is thus designed to provide an overview on health and environment in sustainable development through the Internet.

Environmental Health↗