Stabilising survival selection on pre-senescent expression of a sexual ornament followed by a terminal decline

Senescence is a decrease in functional capacity, increasing mortality rate with age. Sexual signals indicate functional capacity, because costs of ornamentation ensure signal honesty, and are therefore expected to senesce, tracking physiological deterioration and mortality. For sexual traits, mixed associations with age and positive associations with life expectancy have been reported. However, whether these associations are caused by selective disappearance and/or within-individual senescence of sexual signals, respectively, is not known. We previously reported that zebra finches with redder bills had greater life expectancy, based on a single bill colour measurement per individual. We here extend this analysis using longitudinal data and show that this finding is attributable to terminal declines in bill redness in the year before death, with no detectable change in presenescent redness. Additionally, there was a quadratic relationship between presenescent bill colouration and survival: individuals with intermediate bill redness have maximum survival prospects. This may reflect that redder individuals overinvest in colouration and/or associated physiological changes, while below-average bill redness probably reflects poorer phenotypic quality. Together, this pattern suggests that bill colouration is defended against physiological deterioration, because of mate attraction benefits, or that physiological deterioration is not a gradual process, but accelerates sharply prior to death. We discuss these possibilities in the context of the reliability theory of ageing and sexual selection

Nature-based solutions contribution for urban resilience and sustainability

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Evaluating the fire behaviour of cement-based lightweight materials with textile waste incorporation using a cone calorimeter

The conscientious utilization of natural resources and the efficient waste management have become a matter of great concern in recent years due to the harmful impacts on the environment. The construction sector presents itself as one of the sectors that most contributes to raw materials consumption and waste generation, demanding the investigation of more sustainable and ecofriendly building materials, where the valorisation of wastes originated from other industries can be promising. Following the sustainability concept in construction materials, this work investigates the potential use of textile waste in cement-based lightweight construction material, evaluating the fire reaction of the material using the cone calorimeter equipment. The samples were tested at three different radiant heat fluxes (35 kW/m2, 50 kW/m2, 75 kW/m2) to simulate different fire situations. For the highest heat flux, the lightweight construction element with textile waste incorporation showed a Heat Release Rate Average ≤ 18 kW/m2, a peak Heat Release Rate Average ≤ 60 kW/m2, and a Total Heat Release Average ≤ 33 MJ/m2. These results reveal a very satisfactory fire behaviour compared to other materials and show the suitability of using textile waste as lightweight cement-based materials.info:eu-repo/semantics/publishedVersio

Editorial: urban nature-based solutions and green infrastructure as strategies for climate change adaptation

info:eu-repo/semantics/publishedVersio

Edifícios de xisto no concelho de Peso da Régua

A pedra de xisto é um material natural e local comummente utilizado nas construções tradicionais do Concelho de Peso da Régua. Esta zona do Nordeste Português está inserida na região do Douro que é classificada como Património Mundial pela UNESCO. Os muros de divisão de terrenos, de suporte de terras e os edifícios de construção tradicional são os tipos de construção em que a pedra de xisto é o material dominante. Estas construções são parte integrante da paisagem e do património vernacular local, e por isso devem ser valorizados e preservados. Através deste trabalho de investigação foi possível realizar um levantamento dos edifícios de xisto existentes neste concelho, e reunir um conjunto de informações técnicas e construtivas que os caracterizam. Este artigo pretende divulgar informação técnica relativa a detalhes construtivos deste tipo de construção tradicional, focada principalmente nas suas especificidades estruturais. No contexto estrutural, as paredes de alvenaria de pedra de xisto são os elementos estruturais verticais principais. As dimensões e constituição das paredes, dos vãos de janela e de porta, dos cunhais e das padieiras são alguns dos aspectos técnicos e construtivos que merecem especial destaque, tendo em conta que podem influenciar de forma decisiva o comportamento estrutural deste elemento construtivo. Deste modo, pretende-se contribuir para o conhecimento deste tipo de construção, e disponibilizar informação base que possa suportar estudos futuros de modelação numérica e/ou ensaios experimentais do comportamento de paredes em alvenaria de pedra de xisto

Child volunteers in a women's paramilitary organization in World War II have accelerated reproductive schedules

Understanding how conditions experienced during development affect reproductive timing is of considerable cross-disciplinary interest. Life-history theory predicts that organisms will accelerate reproduction when future survival is unsure. In humans, this can be triggered by early exposure to mortality. Previous studies, however, have been inconclusive due to several confounds that are also likely to affect reproduction. Here we take advantage of a natural experiment in which a population is temporarily divided by war to analyze how exposure to mortality affects reproduction. Using records of Finnish women in World War II, we find that young girls serving in a paramilitary organization wait less time to reproduce, have shorter inter-birth intervals, and have more children than their non-serving peers or sisters. These results support the hypothesis that exposure to elevated mortality rates during development can result in accelerated reproductive schedules and adds to our understanding of how participation in warfare affects women. Life history theory predicts that females will adjust reproductive timing in response to environmental challenges. Here the authors show that young girls exposed to higher mortality rates during war give birth earlier and more often than their peers who were not exposed to these conditions

Earth-based render of tabique walls – an experimental work contribution

A research work focused on studying earth render for tabique application purposes is presented. Initially, a brief description of the tabique building technique is provided. The relevance of the application of this traditional building technique is also highlighted. Different compositions of earth render are experimentally analysed and the respective performance is evaluated. Flexural and compressive strengths, workability, drying shrinkage cracking and water resistance are the material properties assessed. A simple earth render is selected as being adequate for tabique building applications and it is applied on the manufacturing of a tabique wall sample. This wall sample is monitored in terms of thermal insulation ability and its thermal transmission coefficient is estimated. Taking into account that there is still a lack of published technical information related to this topic, this paper may contribute to solve this limitation and to give some guidance in future repairing processes of tabique construction. The technological benefit of adding lime or cement with earth is researched. Real tabique timber structure samples are applied in order to validate the obtained experimental results.info:eu-repo/semantics/publishedVersio

Oxidative stress and life histories: unresolved issues and current needs

Life-history theory concerns the trade-offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life-history trade-offs, but the details remain obscure. As life-history theory concerns aspects of investment in the soma that influence survival, understanding the physiological basis of life histories is related, but not identical, to understanding the process of aging. One idea from the field of aging that has gained considerable traction in the area of life histories is that life-history trade-offs may be mediated by free radical production and oxidative stress. We outline here developments in this field and summarize a number of important unresolved issues that may guide future research efforts. The issues are as follows. First, different tissues and macromolecular targets of oxidative stress respond differently during reproduction. The functional significance of these changes, however, remains uncertain. Consequently there is a need for studies that link oxidative stress measurements to functional outcomes, such as survival. Second, measurements of oxidative stress are often highly invasive or terminal. Terminal studies of oxidative stress in wild animals, where detailed life-history information is available, cannot generally be performed without compromising the aims of the studies that generated the life-history data. There is a need therefore for novel non-invasive measurements of multi-tissue oxidative stress. Third, laboratory studies provide unrivaled opportunities for experimental manipulation but may fail to expose the physiology underpinning life-history effects, because of the benign laboratory environment. Fourth, the idea that oxidative stress might underlie life-history trade-offs does not make specific enough predictions that are amenable to testing. Moreover, there is a paucity of good alternative theoretical models on which contrasting predictions might be based. Fifth, there is an enormous diversity of life-history variation to test the idea that oxidative stress may be a key mediator. So far we have only scratched the surface. Broadening the scope may reveal new strategies linked to the processes of oxidative damage and repair. Finally, understanding the trade-offs in life histories and understanding the process of aging are related but not identical questions. Scientists inhabiting these two spheres of activity seldom collide, yet they have much to learn from each other

Oxidative stress and life histories: unresolved issues and current needs.

Life-history theory concerns the trade-offs that mold the patterns of investment by animals between reproduction, growth, and survival. It is widely recognized that physiology plays a role in the mediation of life-history trade-offs, but the details remain obscure. As life-history theory concerns aspects of investment in the soma that influence survival, understanding the physiological basis of life histories is related, but not identical, to understanding the process of aging. One idea from the field of aging that has gained considerable traction in the area of life histories is that life-history trade-offs may be mediated by free radical production and oxidative stress. We outline here developments in this field and summarize a number of important unresolved issues that may guide future research efforts. The issues are as follows. First, different tissues and macromolecular targets of oxidative stress respond differently during reproduction. The functional significance of these changes, however, remains uncertain. Consequently there is a need for studies that link oxidative stress measurements to functional outcomes, such as survival. Second, measurements of oxidative stress are often highly invasive or terminal. Terminal studies of oxidative stress in wild animals, where detailed life-history information is available, cannot generally be performed without compromising the aims of the studies that generated the life-history data. There is a need therefore for novel non-invasive measurements of multi-tissue oxidative stress. Third, laboratory studies provide unrivaled opportunities for experimental manipulation but may fail to expose the physiology underpinning life-history effects, because of the benign laboratory environment. Fourth, the idea that oxidative stress might underlie life-history trade-offs does not make specific enough predictions that are amenable to testing. Moreover, there is a paucity of good alternative theoretical models on which contrasting predictions might be based. Fifth, there is an enormous diversity of life-history variation to test the idea that oxidative stress may be a key mediator. So far we have only scratched the surface. Broadening the scope may reveal new strategies linked to the processes of oxidative damage and repair. Finally, understanding the trade-offs in life histories and understanding the process of aging are related but not identical questions. Scientists inhabiting these two spheres of activity seldom collide, yet they have much to learn from each other

Variation in Reproductive Success Across Captive Populations: Methodological Differences, Potential Biases and Opportunities

Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of model\u27 species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory - the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life-history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency