Life-history evolution under a production constraint

The recently formulated metabolic theory of ecology has profound implications for the evolution of life histories. Metabolic rate constrains the scaling of production with body mass, so that larger organisms have lower rates of production on a mass-specific basis than smaller ones. Here, we explore the implications of this constraint for life-history evolution. We show that for a range of very simple life histories, Darwinian fitness is equal to birth rate minus death rate. So, natural selection maximizes birth and production rates and minimizes death rates. This implies that decreased body size will generally be favored because it increases production, so long as mortality is unaffected. Alternatively, increased body size will be favored only if it decreases mortality or enhances reproductive success sufficiently to override the preexisting production constraint. Adaptations that may favor evolution of larger size include niche shifts that decrease mortality by escaping predation or that increase fecundity by exploiting new abundant food sources. These principles can be generalized to better understand the intimate relationship between the genetic currency of evolution and the metabolic currency of ecology.

Demographic models and the management of endangered species: a case study of the critically endangered Seychelles magpie robin

1. Demographic models are assuming an important role in management decisions for endangered species. Elasticity analysis and scope for management analysis are two such applications. Elasticity analysis determines the vital rates that have the greatest impact on population growth. Scope for management analysis examines the effects that feasible management might have on vital rates and population growth. Both methods target management in an attempt to maximize population growth. 2. The Seychelles magpie robin Copsychus sechellarum is a critically endangered island endemic, the population of which underwent significant growth in the early 1990s following the implementation of a recovery programme. We examined how the formal use of elasticity and scope for management analyses might have shaped management in the recovery programme, and assessed their effectiveness by comparison with the actual population growth achieved. 3. The magpie robin population doubled from about 25 birds in 1990 to more than 50 by 1995. A simple two-stage demographic model showed that this growth was driven primarily by a significant increase in the annual survival probability of first-year birds and an increase in the birth rate. Neither the annual survival probability of adults nor the probability of a female breeding at age 1 changed significantly over time. 4. Elasticity analysis showed that the annual survival probability of adults had the greatest impact on population growth. There was some scope to use management to increase survival, but because survival rates were already high (> 0.9) this had a negligible effect on population growth. Scope for management analysis showed that significant population growth could have been achieved by targeting management measures at the birth rate and survival probability of first-year birds, although predicted growth rates were lower than those achieved by the recovery programme when all management measures were in place (i.e. 1992-95). 5. Synthesis and applications. We argue that scope for management analysis can provide a useful basis for management but will inevitably be limited to some extent by a lack of data, as our study shows. This means that identifying perceived ecological problems and designing management to alleviate them must be an important component of endangered species management. The corollary of this is that it will not be possible or wise to consider only management options for which there is a demonstrable ecological benefit. Given these constraints, we see little role for elasticity analysis because, when data are available, a scope for management analysis will always be of greater practical value and, when data are lacking, precautionary management demands that as many perceived ecological problems as possible are tackled.

Are patterns of growth adaptive?

Models which define fitness in terms of per capita rate of increase of phenotypes are used to analyse patterns of individual growth. It is shown that sigmoid growth curves are an optimal strategy (i.e. maximize fitness) if (Assumption 1a) mortality decreases with body size; (2a) mortality is a convex function of specific growth rate, viewed from above; (3) there is a constraint on growth rate, which is attained in the first phase of growth. If the constraint is not attained then size should increase at a progressively reducing rate. These predictions are biologically plausible. Catch-up growth, for retarded individuals, is generally not an optimal strategy though in special cases (e.g. seasonal breeding) it might be. Growth may be advantageous after first breeding if birth rate is a convex function of G (the fraction of production devoted to growth) viewed from above (Assumption 5a), or if mortality rate is a convex function of G, viewed from above (Assumption 6c). If assumptions 5a and 6c are both false, growth should cease at the age of first reproduction. These predictions could be used to evaluate the incidence of indeterminate versus determinate growth in the animal kingdom though the data currently available do not allow quantitative tests. In animals with invariant adult size a method is given which allows one to calculate whether an increase in body size is favoured given that fecundity and developmental time are thereby increased.

Forecasting extinction risk of ectotherms under climate warming: an evolutionary perspective

1. It has been postulated that climate warming may pose the greatest threat species in the tropics, where ectotherms have evolved more thermal specialist physiologies. Although species could rapidly respond to environmental change through adaptation, little is known about the potential for thermal adaptation, especially in tropical species. 2. In the light of the limited empirical evidence available and predictions from mutation-selection theory, we might expect tropical ectotherms to have limited genetic variance to enable adaptation. However, as a consequence of thermodynamic constraints, we might expect this disadvantage to be at least partially offset by a fitness advantage, that is, the ‘hotter-is-better’ hypothesis. 3. Using an established quantitative genetics model and metabolic scaling relationships, we integrate the consequences of the opposing forces of thermal specialization and thermodynamic constraints on adaptive potential by evaluating extinction risk under climate warming. We conclude that the potential advantage of a higher maximal development rate can in theory more than offset the potential disadvantage of lower genetic variance associated with a thermal specialist strategy. 4. Quantitative estimates of extinction risk are fundamentally very sensitive to estimates of generation time and genetic variance. However, our qualitative conclusion that the relative risk of extinction is likely to be lower for tropical species than for temperate species is robust to assumptions regarding the effects of effective population size, mutation rate and birth rate per capita. 5. With a view to improving ecological forecasts, we use this modelling framework to review the sensitivity of our predictions to the model’s underpinning theoretical assumptions and the empirical basis of macroecological patterns that suggest thermal specialization and fitness increase towards the tropics. We conclude by suggesting priority areas for further empirical research.

Pregnant Adolescents in Vietnam : Social context and health care needs

Background: The number of childbearing adolescents in Vietnam is relatively low but they are more prone to experience adverse outcome than adult women. Reports of increasing rates of abortion and prevalence of STIs including HIV among youth indicate a need to improve services and counselling for these groups. Midwives are key persons in the promotion of young people’s sexual and reproductive health in Vietnam. Aim: The overall aim of this thesis is to describe the prevalence and outcome of adolescent pregnancies in Vietnam (I), to explore the social context and health care seeking behavior of pregnant adolescents (II), as well as to explore the perspectives of health care providers and midwifery students regarding adolescent sexuality and reproductive health service needs (III, IV). Methods: The studies were conducted from 2002 to 2005, combining qualitative and quantitative research methods. A population based prospective survey was used to estimate rates and outcomes of adolescent pregnancies (I). Pregnant and newly delivered adolescents’ experiences of childbearing and their encounters with health care providers were studied using qualitative interviews (II). Health care providers’ perspective on adolescent sexual and reproductive health (ASRH) and views on how to improve the quality of abortion care was explored in focus group discussions (FGD). The values and attitudes of midwifery students about ASRH were investigated using questionnaires and interviews (IV). Descriptive statistics was used to analyse quantitative data (I, IV) and content analysis were applied for qualitative data (II, III, and IV). Findings: Adolescent birth rate was similar to previously reported in Vietnam but lower when compared to other Asian countries. The incidence of stillborn among adolescents was higher than for women in higher reproductive ages. The proportion of preterm deliveries was 20 % of all births, higher than previous findings from Vietnam. About 2 % of the deliveries were home deliveries, more common among women with low education, belonging to ethnic minority and/or living in mountainous areas (I). Ambivalence facing motherhood, pride and happiness but also worries and lack of self-confidence emerged as themes from the interviews; and experience of ‘being in the hands of others’ in a positive, caring sense but also in a sense of subordination in relation to husband, family and health care providers (II). Health care providers at abortion clinics and midwifery students generally disapproved of pre-marital sex, but had a pragmatic view on the need for contraceptive services and counselling to reduce the burden of unwanted pregnancies and abortions for young women. Providers and midwifery students expressed a need for training on ASRH issues (III, IV). Conclusion: Cultural norms and gender inequity make pregnant adolescent women in Vietnam vulnerable to sexual and reproductive health risks. Health care providers experience ethical dilemmas while counselling unmarried adolescents who come for abortion and this has a negative impact on the quality of care. Integrated ASRH in education and training programmes for health care providers, including midwives, as well as continued in-service training on these issues are suggested to improve reproductive health care services in Vietnam.

Perfil hormonal anual de machos e fêmeas adultos de saguis (callithrix jacchus)

Many behavioral and biological variables of animals are expressed in the form of biological rhytms, down by the Circadian Timing System, that synchronize them with the environment from external stimuli such as light. One of them is the secretion profile of most circulating hormones regulated by the hypothalamuspirtuitary axis, which controls functions essential for the survival and reproduction of organisms. The sagüi, Callithrix jacchus, one of the most studied species about their endocrine physiology, is an appropriate subject for evaluating the profile of plasma prolactin and cortisol of adult males and females born in captivity throughout the year. Three male and two adult femelas were housed individually and subjected to natural environmental conditions over two years. Blood samples were used to measure the circulating levels of both hormones by methods radioimmunoassay (RIA) and immunoassay (ELISA), respectively. The analysis during the year of the plasmatic values of both hormones test was performed by ANOVA for repeated measures, the correlation of Spearman, and the test of Friedman and Student's t-test. The levels of prolactin in plasma were higher during the months in which there is a greater incidence of births of baby in the colony, possibly serving for modulating the expression of the behavior of parental care in both sexes. The plasma cortisol showed a lift in anticipation of the station with the highest birth rate and may be associated with the preparation of individual participation in caring for the baby, and also with the establishment of emotional bond between reproductive partners. Thus, this study shows that, despite the variations observed in the environment in which the animals live, plasma levels of prolactin and cortisol vary little throughout the year.

Single-embryo transfer reduces clinical pregnancy rates and live births in fresh IVF and Intracytoplasmic Sperm Injection (ICSI) cycles: a meta-analysis

Background: It has become an accepted procedure to transfer more than one embryo to the patient to achieve acceptable ongoing pregnancy rates. However, transfers of more than a single embryo increase the probability of establishing a multiple gestation. Single-embryo transfer can minimize twin pregnancies but may also lower live birth rates. This meta-analysis aimed to compare current data on single-embryo versus double-embryo transfer in fresh IVF/ICSI cycles with respect to implantation, ongoing pregnancy and live birth rates.Methods: Search strategies included on-line surveys of databases from 1995 to 2008. Data management and analysis were conducted using the Stats Direct statistical software. The fixed-effect model was used for odds ratio (OR). Fixed-effect effectiveness was evaluated by the Mantel Haenszel method. Seven trials fulfilled the inclusion criteria.Results: When pooling results under the fixed-effect model, the implantation rate was not significantly different between double-embryo transfer (34.5%) and single-embryo transfer group (34.7%) (P = 0.96; OR = 0.99, 95% CI 0.78, 1.25). on the other hand, double-embryo transfer produced a statistically significantly higher ongoing clinical pregnancy rate (44.5%) than single-embryo transfer (28.3%) (P < 0.0001; OR: 2.06, 95% CI = 1.64,2.60). At the same time, pooling results presented a significantly higher live birth rate when double-embryo transfer (42.5%) (P < 0.001; OR: 1.87, 95% CI = 1.44,2.42) was compared with single-embryo transfer (28.4%).Conclusion: Meta-analysis with 95% confidence showed that, despite similar implantation rates, fresh double-embryo transfer had a 1.64 to 2.60 times greater ongoing pregnancy rate and 1.44 to 2.42 times greater live birth rate than single-embryo transfer in a population suitable for ART treatment.

A saúde bucal do idoso brasileiro: revisão sistemática sobre o quadro epidemiológico e acesso aos serviços de saúde bucal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Productive and reproductive performance in cattle infected with bovine leukosis virus

Economic losses caused by enzootic bovine leukosis (EBL) have been of interest since World War II, when the neoplastic form of EEL increased dramatically in Europe. Olson (1974) and House et al. (1975) ed that animals with lymphosarcoma caused by the bovine leukosis virus (BLV) had reduced milk yields. a less efficient reproductive performance and high veterinary costs and mortality rates, while many carcasses were rejected at slaughter. However, the actual impact of BLV infection in cattle without lymphosarcoma is not; clear. The purpose of the study reported here was to compare some productive and reproductive responses of cattle that were antibody-positive (BLV+) or negative (BLV-) for BLV.Holstein dairy cows in commercial dairy farms were used in this study. Blood samples were collected and subjected to BLV serological examination by the agar gel immunodiffusion test of Miller & van der Maaten (1976). Animals were then grouped as BLV+ or BLV- according to their serological response to the BLV antigen. Productive and reproductive histories were obtained from individual animal records and the following factors were considered: milk production, calving interval and birth rate. For milk production, we had the daily milk yields of 547 animals, and for calving interval the time between two successive parturitions for 444 cows. These values were examined by ANOVA and when this was significant a Student's t test was carried out for each age group. Birth rates, the percentage of animals that calved in 1 gear, were available for 557 animals and were examined with the Z-two proportion test. For all analyses, P < 0.05 was considered significant.

Turismo e dinâmica demográfica: reflexos da atividade turística no comportamento reprodutivo da mulher no município de Salinópolis, PA

A discussão das relações de mútua dependência entre população e desenvolvimento econômico é complexa e reflete uma preocupação teórica e prática bastante antiga, o que tematraído a atenção de pensadores e pesquisadores ao longo do tempo. A discussão teórica que envolve os fatores motivadores do turismo são também fatores demográficos que têm particular importância na determinação dos níveis e padrões da fecundidade, ou seja, os meios utilizados para se programar a atividade turística em um lugar, impulsionam novos padrões produtivos, que estimulam novos valores, modelos de consumo e estilos de vida, impactando o comportamento reprodutivo da mulher residente no lugar turístico. Diante desses argumentos, o objetivo desta dissertação é analisar e explicar de que forma as transformações geradas pelo desenvolvimento da atividade turística têm afetado a dinâmica da população, especialmente os níveis e padrões da fecundidade da mulher residente no município de Salinópolis (PA). O estudo parte da hipótese geral de que a reorganização socioeconômica e espacial de Salinópolis a partir do desenvolvimento da atividade turística promoveu alterações em sua dinâmica demográfica, particularmente no comportamento reprodutivo da mulher a partir de 1970. Tendo em vista essas considerações, desenvolveu-se um estudo interpretativo onde a base de dados utilizada foram os censos demográficos de 1970 a 2000 e Contagem da População 2007 do IBGE, dados da Secretaria Municipal de Saúde de Salinópolis (SMSS) vinculada ao Sistema de Nascimentos do Ministério da Saúde (Sinasc) e a pesquisa empírica que se desenvolveu por meio de amostragem probabilística estratificada aleatória. Os resultados encontrados evidenciam que a atividade turística não trouxe para a sociedade salinopolitana melhorias significativas no campo da educação, qualificação profissional e geração de emprego e renda, fatores que têm particular importância na determinação dos níveis e padrões da fecundidade, no entanto, a atividade turística afetou o comportamento reprodutivo da mulher em dois momentos distintos. Primeiro com a prevalência de taxas de fecundidade elevadas dado a cultura da valorização de família numerosa associada ao grande contingente de mulher imigrante em idade fértil no município; num segundo momento, a queda acentuada da fecundidade diante as mensagens da modernidade trazidas pela atividade turística, o crescimento do espaço urbano e, principalmente, pela ação das políticas públicas no que diz respeito ao controle da natalidade. No entanto, os resultados da pesquisa dimensionam a prevalência das elevadas taxas da fecundidade em Salinópolis, tal como no estado do Pará e na região Norte, quando comparadas em nível nacional. Nesse contexto, as implicações demográficas geradas pela atividade turística em Salinópolis requerem a elaboração de diagnósticos setoriais e políticas públicas apropriadas.

Immunization of Wistar female rats with 255-Gy-irradiated Toxoplasma gondii: Preventing parasite load and maternofoetal transmission

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parâmetros genéticos para características de desempenho e reprodutivas de aves poedeiras por inferência bayesiana

Pós-graduação em Genética e Melhoramento Animal - FCAV

Mating behaviour, nympho-imaginal development and description of a new Mesabolivar species (Araneae: Pholcidae) from the Brazilian dry forest

A new species of Mesabolivar is described from Brazilian forests: Mesabolivar delclaroi. The mating behaviour, postembryonic development, number of egg sacs and eggs, birth rate, number of instars, developmental time until adulthood, sex ratio and size of cephalothorax (per instar) were recorded. The sexual behaviour was described and categorized into four steps: courtship, pre-copulation, copulation and post-copulation. After hatching, individuals presented five instars until maturity. The mean number of eggs (42 +/- 16.6) and live births (31.5 +/- 3.4) of the first egg sac were significantly greater than that of a second one (23.8 +/- 3.8, and 19.25 +/- 3.9, respectively). The developmental time from birth to adulthood (130.8 +/- 9.6 days) did not differ significantly between egg sacs produced (128.61 +/- 11.1). The size of the cephalothorax did not differ among adults or between sexes. The sex ratio revealed a shift in favour of females (4: 3).

The Emergence of the Post-Socialist Welfare State - The Case of the Baltic States : Estonia, Latvia and Lithuania

This dissertation takes a step towards providing a better understanding of post-socialist welfare state development from a theoretical as well as an empirical perspective. The overall analytical goal of this thesis has been to critically assess the development of social policies in Estonia, Latvia and Lithuania using them as illustrative examples of post-socialist welfare state development in the light of the theories, approaches and typologies that have been developed to study affluent capitalist democracies. The four studies included in this dissertation aspire to a common aim in a number of specific ways. The first study tries to place the ideal-typical welfare state models of the Baltic States within the well-known welfare state typologies. At the same time, it provides a rich overview of the main social security institutions in the three countries by comparing them with each other and with the previous structures of the Soviet period. It examines the social insurance institutions of the Baltic States (old-age pensions, unemployment insurance, short-term benefits, sickness, maternity and parental insurance and family benefits) with respect to conditions of eligibility, replacement rates, financing and contributions. The findings of this study indicate that the Latvian social security system can generally be labelled as a mix of the basic security and corporatist models. The Estonian social security system can generally also be characterised as a mix of the basic security and corporatist models, even if there are some weak elements of the targeted model in it. It appears that the institutional changes developing in the social security system of Lithuania have led to a combination of the basic security and targeted models of the welfare state. Nevertheless, as the example of the three Baltic States shows, there is diversity in how these countries solve problems within the field of social policy. In studying the social security schemes in detail, some common features were found that could be attributed to all three countries. Therefore, the critical analysis of the main social security institutions of the Baltic States in this study gave strong supporting evidence in favour of identifying the post-socialist regime type that is already gaining acceptance within comparative welfare state research. Study Two compares the system of social maintenance and insurance in the Soviet Union, which was in force in the three Baltic countries before their independence, with the currently existing social security systems. The aim of the essay is to highlight the forces that have influenced the transformation of the social policy from its former highly universal, albeit authoritarian, form, to the less universal, social insurance-based systems of present-day Estonia, Latvia and Lithuania. This study demonstrates that the welfare–economy nexus is not the only important factor in the development of social programs. The results of this analysis revealed that people's attitudes towards distributive justice and the developmental level of civil society also play an important part in shaping social policies. The shift to individualism in people’s mentality and the decline of the labour movement, or, to be more precise, the decline in trade union membership and influence, does nothing to promote the development of social rights in the Baltic countries and hinders the expansion of social policies. The legacy of the past has been another important factor in shaping social programs. It can be concluded that social policy should be studied as if embedded not only in the welfare-economy nexus, but also in the societal, historical and cultural nexus of a given society. Study Three discusses the views of the state elites on family policy within a wider theoretical setting covering family policy and social policy in a broader sense and attempts to expand this analytical framework to include other post-socialist countries. The aim of this essay is to explore the various views of the state elites in the Baltics concerning family policy and, in particular, family benefits as one of the possible explanations for the observed policy differences. The qualitative analyses indicate that the Baltic States differ significantly with regard to the motives behind their family policies. Lithuanian decision-makers seek to reduce poverty among families with children and enhance the parents’ responsibility for bringing up their children. Latvian policy-makers act so as to increase the birth rate and create equal opportunities for children from all families. Estonian policy-makers seek to create equal opportunities for all children and the desire to enhance gender equality is more visible in the case of Estonia in comparison with the other two countries. It is strongly arguable that there is a link between the underlying motives and the kinds of family benefits in a given country. This study, thus, indicates how intimately the attitudes of the state bureaucrats, policy-makers, political elite and researchers shape social policy. It confirms that family policy is a product of the prevailing ideology within a country, while the potential influence of globalisation and Europeanisation is detectable too. The final essay takes into account the opinions of welfare users and examines the performances of the institutionalised family benefits by relying on the recipients’ opinions regarding these benefits. The opinions of the populations as a whole regarding government efforts to help families are compared with those of the welfare users. Various family benefits are evaluated according to the recipients' satisfaction with those benefits as well as the contemporaneous levels of subjective satisfaction with the welfare programs related to the absolute level of expenditure on each program. The findings of this paper indicate that, in Latvia, people experience a lower level of success regarding state-run family insurance institutions, as compared to those in Lithuania and Estonia. This is deemed to be because the cash benefits for families and children in Latvia are, on average, seen as marginally influencing the overall financial situation of the families concerned. In Lithuania and Estonia, the overwhelming majority think that the family benefit systems improve the financial situation of families. It appears that recipients evaluated universal family benefits as less positive than targeted benefits. Some universal benefits negatively influenced the level of general satisfaction with the family benefits system provided in the countries being researched. This study puts forward a discussion about whether universalism is always more legitimate than targeting. In transitional economies, in which resources are highly constrained, some forms of universal benefits could turn out to be very expensive in relative terms, without being seen as useful or legitimate forms of help to families. In sum, by closely examining the different aspects of social policy, this dissertation goes beyond the over-generalisation of Eastern European welfare state development and, instead, takes a more detailed look at what is really going on in these countries through the examples of Lithuania, Latvia and Estonia. In addition, another important contribution made by this study is that it revives ‘western’ theoretical knowledge through ‘eastern’ empirical evidence and provides the opportunity to expand the theoretical framework for post-socialist societies.

Latino Teen Pregnancy in Texas: Prevalence, Prevention, and Policy

Texas is home to over one million Latino teens who are at risk for negative reproductive health outcomes, such as teen pregnancy and STIs. Teen pregnancy disproportionately impacts the health of Latino teens in Texas and places them at risk of continued high rates of poverty, school dropout, and unemployment unless Texas makes a concerted effort to reduce its teen pregnancy rate. The birth rate among Latina girls is astonishing: 98 per 1000 Latinas (aged 15-19) are giving birth. This translates to over 32,000 births each year among Latina teens, costing almost $98 million in direct medical expenditures and well over $638 million if other costs are included. Most teens become sexually experienced while they are of school age, which translates to an estimated 414,583 sexually experienced Latino students attending Texas public schools. Of these Latino youth, 237,466 report being currently sexually active, and 89,000 report having had four or more sexual partners in their lifetime. While causes of teen pregnancy are complex, the solutions to teen pregnancy are known. Texas needs an effective, comprehensive approach to address the sexual health needs of Texas Latino youth that includes: statewide implementation and monitoring of evidence-based sex education for middle school and high school students, access to reproductive health services for students who are already sexually experienced, and widespread training on adolescent sexual health for teachers, service providers, and parents. By tackling teen pregnancy, we can positively impact the future and well-being of not only Latinos, but of all Texans, and subsequently can contribute to the social and economic success of Texas.