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Social polyandry, parental investment, sexual selection, and evolution of reduced female gamete size.

Sexual selection in the form of sperm competition is a major explanation for small size of male gametes. Can sexual selection in polyandrous species with reversed sex roles also lead to reduced female gamete size? Comparative studies show that egg size in birds tends to decrease as a lineage evolves social polyandry. Here, a quantitative genetic model predicts that female scrambles over mates lead to evolution of reduced female gamete size. Increased female mating success drives the evolution of smaller eggs, which take less time to produce, until balanced by lowered offspring survival. Mean egg size is usually reduced and polyandry increased by increasing sex ratio (male bias) and maximum possible number of mates. Polyandry also increases with the asynchrony (variance) in female breeding start. Opportunity for sexual selection increases with the maximum number of mates but decreases with increasing sex ratio. It is well known that parental investment can affect sexual selection. The model suggests that the influence is mutual: owing to a coevolutionary feedback loop, sexual selection in females also shapes initial parental investment by reducing egg size. Feedback between sexual selection and parental investment may be common.

Animals↗

Social group size, potential sperm competition and reproductive investment in a hermaphroditic leech, Helobdella papillornata (Euhirudinea: Glossiphoniidae).

Social group size may affect the potential for sperm competition, and this in turn may favour ontogenetic adjustments in testicular mass according to the likely requirements for sperm and spermatophore production. In a number of comparative analyses of testis mass among vertebrate species that differ in mating system or social organization, increasing potential for sperm competition is associated with larger testis size. Intraspecific phenotypic plasticity should be able to produce the same pattern if social group size is heterogenous and reflects differing degrees of average sperm competition, but this intraspecific effect is less well studied. We tested the effect of social groups on both male and female investment in the simultaneously hermaphroditic leech, Helobdella papillornata. Leeches were placed in groups of one, two, four or eight. Sexual investment at the onset of reproductive maturity was quantified as the total testisac volume for male function and total egg volume for female function. We found that testisac volume (statistically adjusted for body size) showed a significant increase with increasing group size. Total egg volume (also adjusted for body size) was unaffected by group size. Our findings indicate adaptive developmental plasticity in male gonad investment in response to the potential for sperm competition.

Animals↗

Female common lizards (Lacerta vivipara) do not adjust their sex-biased investment in relation to the adult sex ratio.

Sex allocation theory predicts that facultative maternal investment in the rare sex should be favoured by natural selection when breeders experience predictable variation in adult sex ratios (ASRs). We found significant spatial and predictable interannual changes in local ASRs within a natural population of the common lizard where the mean ASR is female-biased, thus validating the key assumptions of adaptive sex ratio models. We tested for facultative maternal investment in the rare sex during and after an experimental perturbation of the ASR by creating populations with female-biased or male-biased ASR. Mothers did not adjust their clutch sex ratio during or after the ASR perturbation, but produced sons with a higher body condition in male-biased populations. However, this differential sex allocation did not result in growth or survival differences in offspring. Our results thus contradict the predictions of adaptive models and challenge the idea that facultative investment in the rare sex might be a mechanism regulating the population sex ratio.

Animals↗

Atmospheric CO2 enrichment alters energy assimilation, investment and allocation in Xanthium strumarium.

Energy-use efficiency and energy assimilation, investment and allocation patterns are likely to influence plant growth responses to increasing atmospheric CO2 concentration ([CO2]). Here, we describe the influence of elevated [CO2] on energetic properties as a mechanism of growth responses in Xanthium strumarium. Individuals of X. strumarium were grown at ambient or elevated [CO2] and harvested. Total biomass and energetic construction costs (CC) of leaves, stems, roots and fruits and percentage of total biomass and energy allocated to these components were determined. Photosynthetic energy-use efficiency (PEUE) was calculated as the ratio of total energy gained via photosynthetic activity (Atotal) to leaf CC. Elevated [CO2] increased leaf Atotal, but decreased CC per unit mass of leaves and roots. Consequently, X. strumarium individuals produced more leaf and root biomass at elevated [CO2] without increasing total energy investment in these structures (CCtotal). Whole-plant biomass was associated positively with PEUE. Whole-plant construction required 16.1% less energy than modeled whole-plant energy investment had CC not responded to increased [CO2]. As a physiological mechanism affecting growth, altered energetic properties could positively influence productivity of X. strumarium, and potentially other species, at elevated [CO2].

Atmosphere↗

Achievement goals and perceived ability predict investment in learning a sport task.

BACKGROUND: Contemporary views on motivation suggest that expectancy-value and social-cognitive perspectives can shed light on the important issue of student motivation. AIMS: To test the predictive value of achievement goals on the investment in learning a sport task. Two studies investigated whether investment in learning is affected by achievement goals and perceived ability. SAMPLES: Study 1: 57 school pupils selected from an initial sample of 212. Study 2: 99 pupils selected from 400. Selection was based on motivation and perceived ability scores from questionnaires. Pupils were aged 13-15 years and attended schools in northern France. METHODS: In Study 1 pupils prepared themselves for a sport task with a five-minute period of training. Study 2 pupils prepared themselves with a five-minute period of training after prior failure. RESULTS: Study 1 showed that those who were ego-involved with a low perceived ability had a weaker investment in the training situation than those ego-involved with a high perceived ability, or those task-involved regardless of their perceived ability. Ego-involved pupils used an attributional bias to minimise the effect of effort on performance. Study 2 confirmed these results by underlining the motivational deficits of ego involvement for those with a low perceived ability. CONCLUSIONS: School pupils with high ego involvement in a sport task and low perceived ability show motivational deficits which manifest themselves in less time spent on practising a task. A social-cognitive and expectancy-value perspective appears to be valid for the study of motivational processes in school physical education.

Adolescent↗

Darwinian grandparenting: preferential investment in more certain kin.

Studies on grandparental investment have revealed that mothers' fathers are emotionally closer to their grandchildren than are fathers' mothers. In the current study, it was hypothesized that this difference is caused by the fact that fathers' mothers often have the potential to invest in genetically more certain kin (children through their daughters). To test this hypothesis, 787 participants rated their emotional closeness and exposure to their grandparents and indicated whether they had cousins through paternal and maternal aunts and uncles. Results indicated that participants felt closer to mothers' fathers than fathers' mothers only when alternate investment outlets for fathers' mothers were available. Closeness ratings to fathers' fathers also were reduced when they had grandchildren through their daughters. Exposure to grandparents revealed a similar pattern of findings but did not show the same sensitivity to the presence of more certain kin and did not appear to account for the closeness ratings.

Adolescent↗

Maternal and paternal nitrogen investment in Blattella germanica (L.) (Dictyoptera; Blattellidae).

The investment of nitrogenous materials by female and male German cockroaches Blattella germanica (L.) into their progeny was examined. Adult females maintained on dog food invested 34% of their dry mass and 26% of their nitrogen into an oothecae during their first gonadotrophic cycle. Females maintained on a low- (5%) protein diet and injected simultaneously with [3H]leucine and [14C]hypoxanthine incorporated less [3H]leucine-derived radiolabel in their oothecae than those on a dog food diet (25% crude protein). Females on the low-protein diet incorporated more [14C]hypoxanthine-derived material (primarily as [14C]urates) into their oothecae than they retained in their bodies. Stored [14C]urates were metabolized more readily by females on the low-protein diet. Oothecae obtained from females provided with an [15N]urate-amended diet contained at least four 15N-enriched amino acids, which supports the hypothesis that urates are utilized as a nitrogen resource in these insects. Dietary effects on paternal investment were also found to be significant. Females fed a low-protein diet and their oothecae contained 63% of the radiolabel made available to them at mating when paired with males injected simultaneously with [3H]leucine and [14C]hypoxanthine, whereas dog-food-fed females and their oothecae contained only 17% of the total radiolabel made available to them at mating.

Animals↗

[Investment of time resource in prenatal care by family health staff].

This study is about low-risk pregnant women attended by a family health unit. It aims to describe the time resource the health staff invested and to analyze its configuration in the prenatal monitoring process. Data were collected from 47 women between 20 and 29 years old, who were attended from 2001 to 2003, in the eastside of São Paulo City. The pregnant women were classified according to the health care they received: a first group without health problems, a second with early expert intervention and a third with patients needing dental treatment. In the three groups, more time was invested by health professionals with higher education, followed by community health agents during home visits. Average total time per pregnant woman was 10 hours for the first group and 12 hours for the second and the third group. The time invested in direct care ranged from 59.40% to 80.51%.

Adolescent↗

Changing investment in activities and interests in elders' lives: theory and measurement.

Socioemotional selectivity and gerotranscendence, newer theories with roots in the disengagement theory of aging, provided the theoretical framework for a new measure of perceived change in investment in a variety of pursuits. The 30-item Change in Activity and Interest Index (CAII) was given to a sample of 327 outpatients aged 65-94. Items with at least 30% decreased investment responses included Entertaining in my home, Concern with others' opinions, Shopping and buying things, and Attending social events with new people. Principal Components Analysis of the index with dichotomous recoding (less vs. more or same investment) resulted in four factors: Active Instrumental (AI), Social Intellectual (SI), Spiritual Concerns (SC), and Transcendence (TR). Support for socioemotional selectivity and gerotranscendence is evident in the reported increase of importance of SI pursuits, with concurrent decrease in importance of AI activities among these respondents. Zero-order correlations of component scores with study variables suggest that AI and SI are more clearly related to older age, functional impairment, and negative affect than are SC and TR. The CAII appears to tap several dimensions of change in interests; the index gives geriatric mental health practitioners and researchers a tool to measure an aspect of social development that has been neglected in gerontology.

Activities of Daily Living↗

Investing for efficiency.

The French Revolution set out to abolish hospitals but in fact strengthened them, made them the core of medicine and improved their effectiveness. Mortality rates more than halved between 1789 and 1850. This reduction was bought about by improvement and investment in old hospitals, appropriate separation of institutions and new administrative organisations. Our modern hospitals and institutions started with the French Revolution and have been going through similar cycles of neglect and abolition or concern and investment. This paper will look at the effects of investments, neglect and "pork- barrelling " by successive governments which has led to inappropriate locations of hospitals, sub-standard facilities, inefficient location of facilities within hospitals, outdated equipment, insufficient maintenance and dangers to public health and human safety. Operating costs, consequences of inefficient layout, buildings and sites within a number of Australian hospitals are then analysed. It is then suggested that orderly capital funding on a triennium basis be established in a similar way to university capital funding.

Australia↗

Investment in Research as a National Priority.

The first time a nation made research a national priority was probably in 15th Century Portugal. While the Spanish built large galleons to ferry gold from the New World to Madrid, the Portuguese built small caravels to return with something more valuable: information. A National Navigational Institute was established in Sagres, where Prince Henry collated the raw data being delivered by the caravels: latitude, longitude, ocean depths, coastal landmarks, and current. Slowly, the caravels moved down the western coast of Africa, overcame the nautical and psychological obstacle of rounding the Horn, and slowly pushed up the Eastern coast. Each new voyage built on the incremental knowledge gleaned from the last and the certain knowledge of the ultimate goal. When Vasco DiGama reached India, the price of pepper in Venice plunged. A new route to the spice trade had been established, a route which did not require the payment of costly tributes at regular intervals along the land route, and a wealthy Empire which would last two centuries was established. The National Institutes of Health represent this nation's commitment to the importance of basic research. In the history of all mankind there has never been a greater, more consistent, and publically funded investment to understand the biology of human disease. Like the caravels, research laboratories and clinical trials have steadily moved forward with incremental progress toward a clearly visualized goal-the prevention and treatment of human disease. In the area of cancer research, we have clearly rounded the horn. The understanding of cancer at a basic level has now brought new targets for cancer treatment into sharper focus. We now understand cancer as a genetic disease. No longer do our therapies target a single cancer feature, uncontrolled growth. Instead, new vaccines like MART-1, gp100, p53 and ras peptides are targeting the cancer cell's ability to evade immune surveillance. Anti-angiogenesis agents like endostatin, Col-3, and angiostatin promise to inhibit the tumor's ability to make new blood vessels and convert cancer to a static, chronic disease. One advantage to these new angiogenesis inhibitors is their action against normal endothelial cells, rather than targeting the cancer itself. For this reason, the genetic plasticity of tumor cells, and their ability to develop drug resistance, is no longer relevant. The Clinton administration has recently announced its intention to add $4.7 billion to cancer research, essentially reaffirming the nation's initial investment of the National Cancer Act. The commitment could not have been better timed. When grants are funded at the 20th percentile, peer review does not work well. And when managed care makes clinical research nearly impossible, we erode the purpose of basic research and undermine the essence of our mission: the prevention and cure of human disease. The Administration's investment will prove to be wise. With the knowledge at hand, and the ability to translate this knowledge into new diagnostic, preventive and treatment approaches, we can begin to realistically vision cancer cures. A new era is at hand.

Journal Article↗

Trade-offs between flower number and investment to a flower in selfing and outcrossing varieties of Impatiens hypophylla (Balsaminaceae).

Floral resource allocation was compared on a whole-plant basis between two varieties of Impatiens hypophylla that differ in flower size. There were significant negative correlations between flower number and investments to a flower at both the within-population and between-variety levels. In individual flowers, var. hypophylla with larger flowers invested significantly more resources to male and pollinator-attractive functions, whereas investments to female function did not differ between the varieties. In experimental populations placed in the field, pollinators preferred the larger flowers of var. hypophylla even within the same habitat of var. microhypophylla, which has smaller flowers. There was a significant lack of observed heterozygosity only in var. microhypophylla. Thus, the outcrossing variety had more attractive but fewer flowers, while the selfing variety had less attractive but more abundant flowers.

Journal Article↗

Medical education for women: how good an investment?

Reluctance to train women for medical careers has been justified by the failure of women to use their education. Using data from studies of physician practice patterns and of educational costs, this article presents a preliminary estimate of the "loss" of investment involved in educating women for medicine. Women physicians are estimated to practice an average of two-fifths fewer hours over their lifetimes than do men, with a consequent loss of educational investment of about $55,000. Suggestions are made for reducing this loss. The finding of some loss of investment should not be used as an argument for discriminatory treatment of women seeking a medical education, as the rights of women as individuals must be recognized.

Costs and Cost Analysis↗

5 rules for effective IT investment planning.

For effective IT investment planning, healthcare administrators should: Have a clear business strategy in mind. Use the same comprehensive planning process the organization would for any other significant investment. Anticipate and develop responses to changing dynamics of both the healthcare business and technology environments. Develop an effective governance structure to guide the planning process. Prepare to adapt as IT investment planning needs change.

Capital Expenditures↗

What will it take for disease management to demonstrate a return on investment? New perspectives on an old theme.

BACKGROUND: Disease management programs are expected (and usually contractually required) to reduce total costs in the diseases they manage. OBJECTIVES: To discuss the appropriateness of using utilization indexes in lieu of cost and the importance of reviewing utilization trends to determine whether sufficient opportunity exists for a program to be financially effective; and to conduct an analysis to determine the number of admissions that must be reduced for a program to achieve various levels of return on investment. STUDY DESIGN: Descriptive. METHODS: Historical inpatient cost trends, discharges per 10,000 population, the mean length of stay, and emergency department visits per 10,000 population for acute myocardial infarction, congestive heart failure, asthma, and diabetes mellitus are presented. A "number-needed-to-decrease" analysis is performed to determine the number of admissions or emergency department visits that must be reduced to meet varying levels of return on investment. RESULTS: (1) Hospital days per 10,000 population for these conditions trended downward, while costs during the same period escalated. (2) Discharge and emergency department visit rates per 10,000 population were flat and low during the observation period, while the mean length of stay declined. Results of the number-needed-to-decrease analysis suggest that disease management programs will have to decrease admissions 10% to 30% to cover program fees alone. CONCLUSION: A review of historical utilization trends and a number-needed-to-decrease analysis should be conducted before disease management program implementation to determine whether sufficient opportunity exists to reduce utilization to levels that will ensure a positive return on investment.

Chronic Disease↗

[How to measure efficiency of health investments in enterprises: selected issues].

BACKGROUND: World trends and international organization recommendations point out the necessity of OHS economic appraisal methods improvement in order to ensure effective resources management in companies. MATERIALS AND METHODS: Published world literature on economic appraisal results, recommendations of international organizations, results of the own studies on economic appraisal in the field of health and safety at work in the companies in Poland were the background of the economic appraisal model for Polish companies. Several project assumptions have been adopted. The model of the return of the investment, model based on the company participation and some elements of the net costs formula are recommended for Polish companies in order to appraise efficiency of the health investment. The basic ratio in economic evaluation should be cost/benefit ratio. The project of the economic evaluation algorithm has been elaborated. RESULTS AND CONCLUSIONS: The economic analysis of the health protection and safety at work should include clear division between the internal and external costs. The proposed model could be used for the companies management needs in two directions: to microeconomic efficiency appraisal of investment in programs/intervensions in health and safety at workplace and to analyze the influence of the costs of accidents and occupational diseases and costs of preventive programs on finance management on the company level.

Health Promotion↗

Personal investment predictors of adolescent motivational orientation toward exercise.

The primary purpose of this study was to determine the relationship between the psychosocial components of Personal Investment Theory and exercise behavior among 237 adolescents. Specifically, the adolescents' personal incentives for exercise, perceptions of sense of self, and perceived options for exercise were examined as predictors of physical activity level. A secondary purpose was to determine the interdependence between the components reflecting personal investment and self-reported exercise behavior separately by gender and activity level. Multiple regression analysis revealed that the personal investment variables accounted for 19% of the variance in exercise behavior among male adolescents and 25% of the variance in exercise behavior among female adolescents. Discriminant analysis correctly classified 76.5% of the males and 71.8% of the females as well as 80.4% of high-active adolescents and 73.3% of low-active adolescents on the basis of the three meaning components. Further, the results indicated that the significant predictors of exercise behavior varied as a function of gender as well as the adolescents' level of physical activity.

Adolescent↗

Effect of investments in water supply and sanitation on health status: a threshold-saturation theory.

A general theory on the relationship between water supply and sanitation investments and health, the threshold-saturation theory, is proposed. The theory takes into consideration three variables: health status, socioeconomic status, and sanitation level, and attempts to encompass, for the first time in one general theoretical framework, numerous conflicting empirical findings. The two-tiered S-shaped logistic form of the relationship that is proposed assumes that at the lower end of the socioeconomic spectrum there is a threshold below which investments in community water supplies and/or excreta disposal facilities alone result in little detectable improvement in health status. Similarly, at the higher end of the socioeconomic scale, it is suggested that a point of saturation is reached beyond which further significant health benefits cannot be obtained by investments in conventional community sanitation facilities.A preliminary attempt to validate this model using published data on sanitation level (defined as access to water supply), life expectancy, and adult literacy rates, for 65 developing countries, appears to provide preliminary support for the threshold saturation theory but further empirical validation is required before a quantitative predictive model can be developed.

Developing Countries↗