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PubMed1998

A simultaneous task comparison of differentiated and undifferentiated hemispheric resource theories.

Multiple resource theory and related principles hold that resources are differentiated both within and between cerebral hemispheres (C. D. Wickens, 1984, 1991, 1992). An opposing view is that each hemisphere constitutes a pool of undifferentiated resources (A. Friedman, M. C. Polson, C. G. Dafoe, & S. J. Gaskill, 1982; M. C. Polson & A. Friedman, 1988). Here the authors compare the theories by using dual-task methodology, drawing on tasks emerging from factor analytic studies of lateralized processes. Selective interference occurs when 2 tasks draw on the same process in the same hemisphere but not otherwise, a conclusion further supported by analyses of difficulty trade-off. Differentiation indeed exists within and between hemispheres, but evidence is found for resources not envisaged in multiple resource theory. The results suggest that orthogonal processes represent orthogonal resources, and a full accounting of them is likely to be needed in any complete multiple resource model.

Brain↗
PubMed1997

Everyday functioning and successful aging: the impact of resources.

The goal of this article is to examine differential aging in everyday functioning between resource-rich and resource-poor older adults. Four groups of older adults were identified on the basis of 2 distinct resource factors: a Sensorimotor-Cognitive factor and a Social-Personality factor. The resource-richest group consisted of those participants who were above the median in both factors; those falling below the median in both factors comprised the resource-poorest group; and 2 additional groups consisted of older adults who were above the median in either 1 of the 2 factors. At the level of mean differences, the 4 groups differed in the length of the waking day, the variability in activities, the frequency of intellectual-cultural and social-relational activities, and resting times. Considering age differences there are more and larger negative age effects in the resource-poorest group than in the resource-richest one. The metamodel of selective optimization with compensation is used to interpret the findings.

Activities of Daily Living↗
PubMed1988

Utilization of path-analytic procedures to investigate the role of processing resources in cognitive aging.

Data from two batteries of tests administered to 129 and 233 adults, ranging from 20 to 79 years of age, were analyzed to explore the viability of models postulating that age differences in the quantity or efficiency of processing resources are responsible for many of the age differences observed in cognitive functioning. Path-analysis procedures were used to estimate the direct and indirect, or resource-mediated, effects of age on cognitive performance. Results, with simple speed and memory measures serving as the indexes of processing resources, indicated that there was little support for a strong resource model, and evidence derived from a weak resource model suggested that resource-mediated contributions to age differences are small, relative to those not mediated by processing resources.

Adult↗
PubMed1998

Implications of resource-ratio theory for oral microbial ecology.

The ability to compete for the limited nutrients available to the microorganisms of dental plaque is a strong ecological determinant of the structure of the subgingival ecosystem. This paper introduces a new concept from the field of ecology, resource-ratio theory, and applies it to the dynamics of microbial dental plaque with emphasis on the putative periodontal pathogens. Resource-ratio theory is a mechanistic theory of resource competition that utilizes pairs of growth-limiting nutrients in a stoichiometric fashion to predict zones of competitive dominance, exclusion, and coexistence for organisms competing for these resources. Once these resource pairs are identified for plaque organisms, resource-ratio theory may provide predictions of changes in the microbial community structure of plaque based on directional changes in their resource supply ratios.

Bacteria↗
PubMed2003

Nurse practitioner-client interaction as resource exchange in a women's health clinic: an exploratory study.

Empirical research has thoroughly documented the success of nurse practitioners (NPs) in terms of patient satisfaction and cost-effectiveness. What is missing is the in-depth knowledge of the interactive process through which this is accomplished during a clinic visit. The aim of this study was to understand the special nature and processes of NP and client encounters in the ambulatory primary care context using a resource exchange perspective. An exploratory descriptive design was used to address the following research questions: (i) What do midlife female clients expect in terms of resources to be exchanged prior to a visit with a NP in an ambulatory clinic visit? (ii) What resources are actually exchanged during the clinic visit? (iii) To what extent is there congruence between a woman's expectations and what she is actually receiving from the clinic visit in terms of resources exchanged? The participants included two women health NPs and eight midlife female clients. Data for the study were comprised of audiotaped pre- and postencounter interviews with the clients, audiotapes of the entire clinic visits with the NP and field notes recorded by the researcher of the client visits. Content analysis was conducted using ETHNOGRAPH software. Findings indicated that clients of both NPs had surprisingly similar expectations of receipt of services as well as actual receipt of services. Resources expected and received from the visits included some combination of services, health information, trust, self-disclosure, support, affirmation, time, acceptance and respect. Results of this study suggest that resource exchange theoretical formulations can be applied to NP-client interactions to understand and explain the specific nature of resources the clients expect and receive from a NP during a woman's health clinic visit.

Adult↗
PubMed2003

Temperature dependent larval resource allocation shaping adult body size in Drosophila melanogaster.

Geographical variation in Drosophila melanogaster body size is a long-standing problem of life-history evolution. Adaptation to a cold climate invariably produces large individuals, whereas evolution in tropical regions result in small individuals. The proximate mechanism was suggested to involve thermal evolution of resource processing by the developing larvae. In this study an attempt is made to merge proximate explanations, featuring temperature sensitivity of larval resource processing, and ultimate approaches focusing on adult and pre-adult life-history traits. To address the issue of temperature dependent resource allocation to adult size vs. larval survival, feeding was stopped at several stages during the larval development. Under these conditions of food deprivation, two temperate and two tropical populations reared at high and low temperatures produced different adult body sizes coinciding with different probabilities to reach the adult stage. In all cases a phenotypic trade-off between larval survival and adult size was observed. However, the underlying pattern of larval resource allocation differed between the geographical populations. In the temperate populations larval age but not weight predicted survival. Temperate larvae did not invest accumulated resources in survival, instead they preserved larval biomass to benefit adult weight. In other words, larvae from temperate populations failed to re-allocate accumulated resources to facilitate their survival. A low percentage of the larvae survived to adulthood but produced relatively large flies. Conversely, in tropical populations larval weight but not age determined the probability to reach adulthood. Tropical larvae did not invest in adult size, but facilitated their own survival. Most larvae succeeded in pupating but then produced small adults. The underlying physiological mechanism seemed to be an evolved difference in the accessibility of glycogen reserves as a result of thermal adaptation. At low rearing temperatures and in the temperate populations, glycogen levels tended to correlate positively with adult size but negatively with pupation probability. The data presented here offer an explanation of geographical variation in body size by showing that thermal evolution of resource allocation, specifically the ability to access glycogen storage, is the proximate mechanism responsible for the life-history trade-off between larval survival and adult size.

Adaptation, Physiological↗
PubMedDate not supplied

A comparison of the psychological resources of adolescents at low and high risk of mistreating their children.

OBJECTIVE: Our objective was to compare the psychological resources of pregnant teenagers who are at low and high risk for mistreating their children. METHOD: We studied 71 participants in a comprehensive, adolescent-oriented maternity program. During the prenatal period, the Family Stress Checklist was used to quantify child abuse potential, with scores > or =25 defining high risk. Information about the social context of the pregnancy and maternal psychological resources was obtained with self-administered questionnaires. A composite psychological resource variable was computed by summing the z scores for intelligence, mental health, and mastery, with scores < or =0 defining the low-resource group. RESULTS: Of the 71 teenagers, 26 (36.6%) were classified as high risk for child abuse and neglect. Compared with low-risk teens, high-risk teens had more behavioral problems, lower psychological resource scores (mean +/- SD of z score: -0.98 +/- 2.02 compared with 0.39 +/- 1.79; P =.004), and were more likely to have low psychological resources (69.2% compared with 44.4%; P =.04). CONCLUSIONS: Pregnant teenagers who are at risk for child abuse and neglect exhibit fewer psychological resources than their low-risk peers do, and may therefore benefit preferentially from intensive, in-home intervention.

Adaptation, Psychological↗
PubMed1999

Plant genetic resources: what can they contribute toward increased crop productivity?

To feed a world population growing by up to 160 people per minute, with >90% of them in developing countries, will require an astonishing increase in food production. Forecasts call for wheat to become the most important cereal in the world, with maize close behind; together, these crops will account for approximately 80% of developing countries' cereal import requirements. Access to a range of genetic diversity is critical to the success of breeding programs. The global effort to assemble, document, and utilize these resources is enormous, and the genetic diversity in the collections is critical to the world's fight against hunger. The introgression of genes that reduced plant height and increased disease and viral resistance in wheat provided the foundation for the "Green Revolution" and demonstrated the tremendous impact that genetic resources can have on production. Wheat hybrids and synthetics may provide the yield increases needed in the future. A wild relative of maize, Tripsacum, represents an untapped genetic resource for abiotic and biotic stress resistance and for apomixis, a trait that could provide developing world farmers access to hybrid technology. Ownership of genetic resources and genes must be resolved to ensure global access to these critical resources. The application of molecular and genetic engineering technologies enhances the use of genetic resources. The effective and complementary use of all of our technological tools and resources will be required for meeting the challenge posed by the world's expanding demand for food.

Agriculture↗
PubMed1990

Learned resourcefulness, drinking, and smoking in young adults.

The purpose of this study was to examine the relationship between learned resourcefulness and two common addictive behaviors, namely, drinking and smoking. Male and female college students (N = 175) completed the Self-Control Schedule (SCS), the Quantity-Frequency-Variability questionnaire, and a smoking history form. Learned resourcefulness was related to self-reported patterns of alcohol consumption; specifically, heavy drinking subjects were lower in learned resourcefulness than were light and moderate drinkers who, in turn, were lower in learned resourcefulness than were infrequent drinkers and abstainers. Learned resourcefulness was only modestly related to smoking, with students who had never smoked evidencing somewhat higher learned resourcefulness than ex-smokers and current smokers. Overall, these data provide correlational support for the notion that learned resourcefulness may protect young adults against substance abuse.

Adult↗
PubMed2002

Predictors of resourcefulness in school-aged children.

Children need to develop appropriate cognitive-behavioral repertoires to maintain mental health and prevent depression. Resourcefulness is learned throughout life in the context of one's environment. However, environmental or situational factors and individual factors in children's development of resourcefulness have not been studied. This study examined the effects of the situational factors of family context (one or two parents, and number of siblings) and maternal characteristics (employment, learned resourcefulness, and adaptive functioning), and individual (child) factors (gender, academic performance, and automatic thoughts) on learned resourcefulness in school-aged children. A convenience sample of 122 fifth and sixth graders was recruited from four public schools. The child's automatic thoughts and maternal resourcefulness were predictors of child's resourcefulness. Further research is needed to examine additional factors that may promote resourcefulness in school-aged children, so that appropriate nursing strategies can be implemented.

Adaptation, Psychological↗
PubMed2006

Impact of physical and psychological resources on functional autonomy in old age.

Functional autonomy is a core condition of successful ageing. To maximize autonomous functioning is not only a claim of social policy but also primarily an individual need. Part of the challenge of preventing unnecessary dependence in old age is to recognize the diversity among the elderly and the different availability of their physical, psychological and social resources. The aim of this study is to examine the age- and time-related changes in functional autonomy (activities of daily living, ADL, and instrumental activities of daily living, IADL) and the psychophysical resources correlated with these changes in a sample of 441 healthy elderly persons aged 65-95. Furthermore, we are interested in the long-term predictive power of physical resources (objective and subjective health, physical strength) and psychological resources (memory) on functional autonomy. Results show significant age- and time-related deteriorations in functional autonomy and in most psychophysical resources. Structural equation model analyses were performed to test the long-term predictive power of these resources. Results suggest that ADL is better predicted by physical resources than by psychological ones, but for IADL the reverse is the case; here memory variables play a dominant role. Physical and psychological variables are thus specifically related to different components of functional autonomy. This has to be taken into account in the development of preventive and intervention programmes.

Activities of Daily Living↗
PubMed2004

Priority versus brute force: when should males begin guarding resources?

When should males begin guarding a resource when both resources and guarders vary in quality? This general problem applies, for example, to migrant birds occupying territories in the spring and to precopula in crustaceans where males grab females before they molt and become receptive. Previous work has produced conflicting predictions. Theory on migrant birds predicts that the strongest competitors should often arrive first, whereas some models of mate guarding have predicted that the strongest competitors wait and then simply usurp a female from a weaker competitor. We build a general model of resource guarding that allows varying the ease with which takeovers occur. The model is phrased in terms of mate-guarding crustaceans, but the same logic can be applied to other forms of resource acquisition where priority plays a role but takeovers might be possible too. The race to secure breeding positions can lead to strong competitors (large males) taking females earliest, even though this means accepting a lower-quality female. Paradoxically, this means that small males, which have fewer breeding opportunities, are more choosy than larger ones. Such solutions are found when takeovers are impossible. The easier the takeovers and the higher the rate of finding guarded resources, the more likely are solutions where guarding durations are short, where strong competitors begin guarding only just before breeding, and where they do this by usurping the resource. The relationship between an individual's competitive ability and its timing of resource acquisition can also be nonlinear if takeovers are moderately common; if this is the case, then males of intermediate size guard the longest.

Animals↗
PubMed2006

Optimizing time and resource allocation trade-offs for investment into morphological and behavioral defense.

Prey organisms are confronted with time and resource allocation trade-offs. Time allocation trade-offs partition time, for example, between foraging effort to acquire resources and behavioral defense. Resource allocation trade-offs partition the acquired resources between multiple traits, such as growth or morphological defense. We develop a mathematical model for prey organisms that comprise time and resource allocation trade-offs for multiple defense traits. Fitness is determined by growth and survival during ontogeny. We determine optimal defense strategies for environments that differ in their resource abundance, predation risk, and defense effectiveness. We compare the results with results of simplified models where single defense traits are optimized. Our results indicate that selection acts in favor of integrated traits. The selective advantage of expressing multiple defense traits is most pronounced at intermediate environmental conditions. Optimizing single traits generally leads to a more pronounced response of the defense traits, which implies that studying single traits leads to an overestimation of their response to predation. Behavioral defense and morphological defense compensate for and augment each other depending on predator densities and the effectiveness of the defense mechanisms. In the presence of time constraints, the model shows peak investment into morphological and behavioral defense at intermediate resource levels.

Animals↗
PubMed2001

Age differences in stress, social resources, and well-being in middle and older age.

The present study examines the interrelationships among the constructs of social resources, stress, and well-being in middle-aged and older adults. Two samples of 489 middle-aged adults (41-43 years) and 449 older adults (61-63 years) from the Interdisciplinary Longitudinal Study of Adult Development were compared with respect to the availability of social resources, levels of stress, and well-being. The data were used to construct separate structural equation models explaining the influence of stress and social resources on well-being in the two groups. The results indicate higher levels of health-related stress and similar levels of social resources in the older group. Structural equation models and examination of total and indirect effects confirmed that a stress-suppression model has the best fit in explaining the interrelationships between stress, social resources, and well-being. There was a strong effect of stress on well-being, no direct effect of social resources on well-being, and a mediating effect of stress on well-being. The relative contributions of stress and resources to well-being were comparable between age groups.

Adult↗
PubMed2006

Are socially disadvantaged neighbourhoods deprived of health-related community resources?

BACKGROUND: Recent work in a number of countries has identified growing geographical inequalities in health between deprived and non-deprived neighbourhoods. The health gaps observed cannot be entirely explained by differences in the characteristics of individuals living in those neighbourhoods, which has led to a concerted international public health research effort to determine what contextual features of neighbourhoods matter. This article reports on access to potentially health-promoting community resources across all neighbourhoods in New Zealand. Prevailing international opinion is that access to community resources is worse in deprived neighbourhoods. METHODS: Geographical Information Systems were used to calculate geographical access to 16 types of community resources (including recreational amenities, and shopping, educational and health facilities) in 38,350 small census areas across the country. The distribution of these access measures by neighbourhood socioeconomic deprivation was determined. RESULTS: For 15 out of 16 measures of community resources, access was clearly better in more deprived neighbourhoods. For example, the travel time to large supermarkets was approximately 80% greater in the least deprived quintile of neighbourhoods compared with the most deprived quintile. CONCLUSIONS: These results challenge the widely held, but largely untested, view that areas of high social disadvantage have poorer access to community resources. Poor locational access to community resources among deprived neighbourhoods in New Zealand does not appear to be an explanation of poorer health in these neighbourhoods. If anything, a pro-equity distribution of community resources may be preventing even wider disparities in neighbourhood inequalities in health.

Community Networks↗
PubMedDate not supplied

Patient flow based allocation of hospital resources.

The current practice of allocating resources within a hospital introduces peaks and troughs in the workloads of departments and leads therefore to loss of capacity. This happens when requirements for capacity coordination are not adequately taken into account in the decision making process of allocating resources to specialties. The first part of this research involved an analysis of the hospital's production system on dependencies between resources, resulting in a number of capacity coordination requirements that need to be fulfilled for optimized resource utilization. The second, modelling, part of the study involved the development of a framework for resource management decision making, of a set of computer models to support hospital managerial decision making on resource allocation issues in various parts of the hospital, and of an implementation strategy for the application of the models to concrete hospital settings. The third part of the study was devoted to a number of case-studies, illustrating the use of the models when applied in various resource management projects, such as a reorganization of an operating theatre timetable, or the development of a master plan for activities of a group of general surgeons serving two locations of a merged hospital system. The paper summarizes the main findings of the study and concludes with a discussion of results obtained with the new allocation procedure and with recommendations for future research.

Bed Occupancy↗
PubMedDate not supplied

Resource loss predicts depression and anxiety among patients treated with an implantable cardioverter defibrillator.

OBJECTIVE: Many patients treated with an implantable cardioverter defibrillator (ICD) experience clinically significant depression and anxiety after ICD implantation. As ICD use continues to evolve, it is important to understand the correlates of depression and anxiety to identify patients at greatest risk of poor psychological functioning. Conservation of resources theory, a general theory of stress, states that people experience greater stress if they perceive that they are losing personal, social, and material resources. We hypothesized that perceptions of resource loss would be related to symptoms of depression and anxiety after controlling for other known predictors. METHODS: One hundred patients treated with an ICD completed standardized depression and anxiety questionnaires along with questionnaires assessing social support, physical functioning, and resource loss. Clinical variables for patients were obtained from prospectively obtained medical records. RESULTS: Over 20% of the sample exhibited elevated symptoms of depression and anxiety. Patients' depression levels were associated with poor social support, poor physical functioning, a history of depression, and a greater length of time since ICD implantation. Having experienced one or more clinical ICD shocks was related to depression but not anxiety. Higher levels of perceived resource loss were associated with higher levels of both depression and anxiety after controlling for all other predictors. CONCLUSIONS: Resource loss may help to determine psychological distress after ICD implantation. Understanding how resource loss contributes to depression and anxiety may help to identify patients at greatest risk of poor psychological functioning and may suggest treatment strategies.

Adult↗
PubMed2000

Developmental trade-offs and life histories: strategic allocation of resources in caddis flies.

Resource allocation trade-offs during development are potentially very important in the evolution of organism morphology and life-history strategy However, they have rarely been demonstrated empirically. To what extent the division of limited resources between growing organs is a consequence of particular developmental pathways or varies strategically in line with life-history predictions is unknown. It has been demonstrated in a number of holometabolous insects that altering the resources available at pupation changes the pattern of allocation to adult tissues, but this has not been examined in a life-history context. Using caddis flies (Trichoptera), we show here that the effect of depleted larval resources on the pattern of somatic and reproductive investment is not fixed but varies between species with different life-history patterns. In particular, we demonstrate that, in a long-lived species, thorax size is preserved, which contrasts with the pattern previously observed in a short-lived species. That the adult body can be differentially altered by the same resource depletion in the larvae demonstrates that the allocation of resources amongst body parts is not a consequence of fixed pathways during development. Rather, the allocation of resources during development can occur in a manner consistent with the minimization of the effects on adult fitness.

Animals↗