Comparison of factors affecting daily variation of blood pressure in Filipino-American and Caucasian nurses in Hawaii

Although several studies have examined differences in daily blood pressure variability between African-American and Caucasian groups in the United States, little is known about the blood pressure variation of other ethnic groups. This study examined the effects of emotional state, setting, posture, and ethnicity on the ambulatory blood pressure of female health care workers (nurses and nurse's aides) from 2 ethnic groups: Filipino-Americans (N = 38) and Caucasians (N = 22). Ambulatory blood pressure measurements were obtained at 15-min intervals during a typical work day. Participants reported in a diary their setting (work or home), posture, mood, and specific activity at each measurement. The effects of these factors and ethnicity were examined using analysis of variance (ANOVA). The results show that for all subjects blood pressure was higher at work (P < 0.05), while standing (P < 0.05), during reports of negative moods (anxiety, anger, or sadness) (P < 0.05), and while engaging in activities such as interacting with fellow staff members at work and “washing up” at home. However, the Filipino-American women reported negative moods more frequently than their Caucasian counterparts (P < 0.05), had a greater proportion of readings taken while standing at work, and reacted differently than the Caucasian women to some specific activities; for instance, their blood pressure was not elevated when doing household chores. These results suggest that the extent of blood pressure variation in daily life may depend upon cognitive processes which are influenced by the cultural background and emotional state of the individual. They further suggest that ethnicity has an important impact on blood pressure variation. Am J Phys Anthropol 106:373–383, 1998. © 1998 Wiley-Liss, Inc.     

Logit effect values and efficiency of significance tests when a noncollapsible variable is omitted

For linear models, randomization of the assignment to the levels of a variable A is a sufficient condition to obtain correct estimates of the effect of A on another variable B. For logit models, the omission of a relevant variable Z often results in invalid estimates of the effect of A and in a loss of power of the significance test. The values of this underestimation and of the loss of power are evaluated here asymptotically and from simulation studies. Consequences for practical use of logit models in randomized settings are underlined.     

Ecological consequences of altered hydrological regimes in fragmented ecosystems in southern Australia: Impacts and possible management responses

Abstract Although the potential impacts of rising water tables and secondary salinization on agricultural land in southern Australia have been recognized for some time, it is only recently that the impacts on native vegetation have been considered. Despite the likely extent and severity of the problem, no comprehensive approach to assessing the impact of salinity upon native vegetation has been attempted to date. In the present paper, we discuss the causes and impacts of rising water tables and dryland salinity, assess the levels of risk in different ecosystem types and consider the possibilities for the maintenance of biodiversity and ecosystem function in vegetation at risk. We examine the salinity risk to woodland vegetation in the Western Australian (WA) wheatbelt, and consider both broad‐scale context and finer‐scale variation within individual patches of vegetation. From this information, we develop a set of conceptual models of the potential impacts of shallow saline water tables on ecosystem structure and processes in remnant vegetation in agricultural areas, particularly in the WA wheatbelt. First, we suggest that fine‐scale variability in surface topography and soil characteristics may play an important role in limiting the impacts of rising saline water tables. The outcome will depend on the interaction of the heterogeneity of the impact, species distribution in relation to small‐scale environmental heterogeneity and variation in species response to hydrological change. Second, we suggest that shallow saline water tables can be considered to cause an ‘edge effect’, which moves inwards from the edge of remnants of native vegetation. Finally, we consider how saline surface flows exacerbate the effects of shallow saline water tables and hasten vegetation decline in remnant areas. We put these models forward as hypotheses to be tested in different situations. We contrast the situation of secondary salinization in Australian vegetation with that of naturally saline systems in Australia and elsewhere, and suggest that these systems may provide important signposts toward developing management approaches for vegetation at risk. In conclusion, we consider the need to set priorities for the protection and restoration of natural vegetation at risk from altered hydrology, based on an assessment of relative threat and probability of persistence or recovery. We highlight the urgency for action that protects native vegetation from the increasing risks of rising water tables.     

东北草原羊草种群结实特性与气候年变化的关系

对３个固定样地的羊草（Ｌｅｙｍｕｓ ｃｈｉｎｅｎｓｉｓ（Ｔｒｉｎ．）Ｔｚｖｅｌ．）种群连续１２￣１６年的调查和测定及其与不同生长发育阶段气候因子的相关分析,表明羊草种群结实数量和籽实重量均与形成这些性状的生育期内,及其以前各生育期不同阶段的光照时间、积温、降水量有着一定程度的相关关系。从分蘖株的营养生长到生殖生长,包括开花、授粉、受精、胚珠发育为种子形成的整个过程中,较低的温度和生长季前期较多的光     

东北草原羊草种群结实特性与气候年变化的关系

Leymus chinensis（Trin.）Tzvel. is a fine herbage, which is a perennial rhizome grass species with high potentiality of vegetative propagation. The quantitative characters of fruit-bearing and grain weight of the population were successively investigated in three fixed stands from 1983 to 1998,analyzing the relationship between these characters and the climatic factors in different growing and developing stages. Certain degree of correlations were found between the number of seeds and grain weight of the population and different time of sunshine, temperature and rainfall accumulation before and during the growing and developing stages. From vegetative to reproductive growth of the tiller, including flowering, pollination, fertilization, and ovule development and seed formation, lower accumulated temperature and longer day light during the early growth season promoted fruit-bearing of the population, and vice versa. From turning green to fruit-ripening stage, longer sunshine duration benefited while higher accumulated temperature inhibitted nutrient deposition in the grain. Furthermore rainfall was also good to nutrient collection in the grain from turning green to milky stage,not from milky stage to mature stage. Growth and development of the winter tillers would affect the flowering, fruit-bearing, as well as the quality and quantity of seed production in the following year. Therefore, the number of fruit-bearing and the grain weight of the population could be predicted by the length of sunshine duration from August to September of the previous year and amount of rainfall in May of the present year,but the quantitative variation that estimated by simple climatic factor model was only 29.27%-35.76%.     

Vernalization,a Switch in Initiation of Flowering,Promotes Differentiation and Development of Spikelet in Winter Wheat

Vernalization is a decisive physiological process for heading, flowering and graining of biennial plants. Variable duration of low-temperature treatment has effects on lateral morphogenesis, such as spike initiation, floral development and graining rate in winter wheat ( Triticum aestivum L.). The investigation data showed that the duration of vernalization treatment was a decisive factor for the initiation of spike relevant to the time of initiation; the longer the duration at low temperature, the earlier the spike initiation in winter wheat. In the process of the spike differentiation, relatively lower temperature and longer differential time benefited for spike differentiation. Under laboratory condition, a low-temperature treatment for 45 d was optial for flower differentiation and graining in winter wheat. It is novelly recognized that vernalization treatment is essential for development of both spikes and spikelets, besides for promoting initiation of differentiation in winter wheat.     

Effects of Changing Rainfall on the Limnology of a Mediterranean,Flowthrough‐Seepage Chain of Lakes

Relationships between groundwater and lake ecology are often overlooked, but they may be strong, particularly in seepage lakes. As a result, the nature and degree of groundwater effects on lakes are usually neglected. In this study interactions among rainfall, groundwater and surface water and their limnological effects were traced seasonally for two years of changing rainfall in a Spanish flowthrough, seepage lake complex. Cumulative rainfall dictated recharge of groundwater with delays of nine months. Groundwater discharge, in turn, increased surface discharge downstream. Mediated by the geographical setting of lakes, both fluxes impinged on lake water renewal time, but effects of the latter on limnological variables were much stronger at the district scale than at the single lake scale. These water‐renewal effects included the following: decreasing salinity, total phosphorus concentration and phytoplankton biomass and increasing water transparency and total nitrogen concentration as water renewal shortened, the nitrogen effect arising because of nitrate‐rich water entering the lakes as groundwater levels rose. This complex response of a Mediterranean lake district to water availability may also be expected in cold temperate lakes as climate change effects become stronger. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effects of budget constraints on conservation network design for biodiversity and ecosystem services

Limited budgets and budget cuts hamper the development of effective biodiversity conservation networks. Optimizing the spatial configuration of conservation networks given such budget constraints remains challenging. Systematic conservation planning addresses this challenge. Systematic conservation planning can integrate both biodiversity and ecosystem services as conservation targets, and hence address the challenge to operationalize ecosystem services as an anthropocentric argument for conservation. We create two conservation scenarios to expand the current conservation network in the Dutch province of Limburg. One scenario focuses on biodiversity only and the other integrates biodiversity and ecosystem services. We varied conservation budgets in these scenarios and used the software Marxan to assess differences in the resulting network configurations. In addition, we tested the network’s cost-effectiveness by allocating a conservation budget either in one or in multiple steps. We included twenty-nine biodiversity surrogates and five ecosystem services. The inclusion of ecosystem services to expand Limburg’s conservation network only moderately changed prioritized areas, compared to only conserving biodiversity. Network expansion in a single time-step is more efficient in terms of compactness and cost-effectiveness than implementing it in multiple time-steps. Therefore, to cost-effectively plan conservation networks, the full budget should ideally be available before the plans are implemented. We show that including ecosystem services to cost-effectively expand conservation networks can simultaneously encourage biodiversity conservation and stimulate the protection of conservation-compatible ecosystem services.     

REFOCUSING THE RESPONSIVENESS REQUIREMENT

Many guidelines for international research require that studies be responsive to host community health needs or health priorities. Although responsiveness possesses great intuitive and rhetorical appeal, existing conceptions are confusing and difficult to apply. Not only are there few examples of what research the responsiveness requirement permits and what it rejects, but its application can lead to contradictory results. Because of the practical difficulties in applying responsiveness and the danger that misapplying responsiveness could harm the interests of developing countries, we argue that responsiveness should be refocused in three ways: in terms of (1) who enforces it, (2) under what standard, and (3) in what cases. We conclude that responsiveness should be applied by host country officials at the policy level with the exercise of judgment when externally funded research threatens to displace scarce local resources.     

Using Realistic Evaluation to understand how interventions work on dairy farms

Interventions that aim to help farmers change on-farm practices recommend that advisors communicate effectively with farmers, work collaboratively to set goals and provide farmers with resources that are applicable to the farm context. We developed an intervention that aimed to help farmers modify and use a standard operating procedure (SOP) for colostrum management; failure of passive transfer of immunoglobulins is common on dairy farms and SOPs for colostrum management are increasingly required by farm animal welfare assurance programs. We used Realistic Evaluation to evaluate whether, how and why our intervention to help farmers modify and use SOPs for colostrum management facilitated change and provide recommendations based on our approach that can improve the design and implementation of future interventions. We used a multiple case study on five farms over 8 months, collecting data through interviews, participant observation, document analysis and field notes. We identified three mechanisms that influenced whether participants modified and used their SOP. The purpose mechanism distinguished between participants who thought the aim of the SOP was for farm staff to learn and understand how to complete a task versus those who thought that the SOP was only useful for compliance with assurance programs. The utility mechanism distinguished between participants who thought that the SOP would be helpful for daily use on their farm, versus those who did not. The physical text mechanism distinguished between participants who used the templates we provided to modify and use their SOP, versus those who did not. A key contextual factor on all farms was participant belief of having capable and engaged staff on their farm; modification and use of the SOP did not occur unless this was the case. To facilitate change, intervention developers should actively participate in the intervention to develop an understanding of farmer needs, understand the purpose behind different goals set by farmers and integrate tools, advice and resource demonstrations when possible. We conclude that Realistic Evaluation is a useful framework for evaluating how contexts and mechanisms generate outcomes on farms, and to understand how, and in which contexts, complex interventions facilitate change. We suggest that this approach can improve the success of interventions and help direct the approaches used on different farms.