Fortress defense in social aphids

Dissertação de mestrado em Evolução e Biologia Humanas, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A idade à morte é um dos parâmetros a ser estimado pelo antropólogo forense, aquando da construção do perfil de um determinado indivíduo. O objectivo de tal análise é tentar estabelecer uma relação entre a idade cronológica e a idade biológica dos resquícios ósseos. São várias as metodologias utilizadas, sendo que a abordagem morfológica, se apresenta como mais recorrente, pois é, de certa forma, mais intuitiva. Contudo, os métodos microscópicos podem, em determinadas situações, revelar-se de extrema utilidade. A estimativa da idade em adultos baseia-se na observação da senescência intrínseca ao indivíduo. Este processo fisiológico tem bases celulares, logo não é de estranhar que a histologia tenha vindo a ser usada como ferramenta para aceder às microestruturas, que permitem estabelecer uma relação com a idade. O ponto fulcral deste projecto é testar a aplicabilidade da histomorfometria óssea na estimativa da idade, através do uso de metodologias práticas e de fácil execução. Esta investigação pretende, com base numa amostra forense de clavículas provenientes de 18 indivíduos, 10 do sexo feminino e 8 do sexo masculino, estabelecer uma relação entre a idade à morte e dois componentes histológicos, a percentagem de osso não remodelado e aérea cortical relativa. Os resultados obtidos foram altamente condicionados pelo número da amostra tendo um carácter preliminar. Não foi possível estabelecer uma relação entre a percentagem de osso não remodelado e a idade, devido a um conjunto de situações condicionantes. Em relação à área cortical relativa, foi possível observar que esta exibe uma tendência para diminuir em indivíduos mais velhos, já que segundo os resultados obtidos, as principais diferenças encontram-se nos dois extremos etários. Os indivíduos mais jovens apresentam uma área cortical relativa superior (63,66%) quando comparados aos indivíduos mais velhos (57,96%). Esta variável parece ser ainda influenciada pelo sexo, chegando mesmo a existir, no grupo etário dos 40 aos 49 anos, uma diferença de aproximadamente 16%. Sempre que possível, os resultados obtidos, ou a falta destes, foram analisados criticamente, sendo que o condicionamento da amostra revelou-se um grande impedimento ao presente estudo. Um balanço geral da metodologia usada, quer ao nível da preparação para a histologia, quer na análise microscópica e com recurso ao scâner. Esta última revelou-se de mais fácil aplicação, embora careça de resultados mais fidedignos. O desenvolvimento de investigações, que visem a aplicação da histologia na estimativa da idade, é um processo premente e basilar, dado existirem empiricamente menos estudos na área, comparativamente aos métodos morfológicos. Deste modo, pensa-se que apesar dos resultados obtidos, novos projectos poderão ser alcançados, com base na temática em estudo.Age at death is one of the key objectives that need to be estimated by the forensic anthropologist, when building the profile of an individual. The aim of this analysis is to establish a relationship between chronological age and the age observed in human skeletal remains. Several methods are used for this purpose, and the morphological approach seems to be the most recurrent, because somehow it is more intuitive. However, the microscopic methods can, under certain circumstances, be extremely useful. The age estimation in adults is based on the observation of the natural senescence, inherent to the individual. This physiological process has a cellular basis, so it is not unpredictable that histology has been used as a tool to access these microstructures, which ultimately may de related with age. The main goal of this project is to test the applicability of bone histomorphometry in the estimation of age at death, through the use of methods that are, at its core, practical and easy to perform. The current investigation is based on forensic samples of clavicles from 18 individuals (10 females and 8 males). It was intended to establish a relationship between age at death and two histological components, the percentage of unremodeled bone and the relative cortical area. The results were highly conditioned by the sample. Therefore emphasis is placed in the preliminary character of those. It was not possible to establish an association between the percentage of unremodeled bone and age at death, due to a set of circumstances that restricted all the analysis. Regarding the analysis of the cortical relative area, it was possible to verify that this component presents a downward trend in older individuals, since the main differences were found in extreme ages. Thereby younger individuals present a higher value of cortical area (63,66%) when compared with older individuals (57,96%). This variable seems to be sexrelated, since in the age group of 40 to 49 years, it was possible to verify about 16% of difference between sexes. Whenever possible, all the results, or the lack of them, were critically analyzed. It is important to state that the sample size was a major drawback to this study. Nevertheless it was still possible to come up with some hypotheses that may in theory explain the results. A general deliberation of the methodology used was performed both in terms of the preparation for histology as well as towards the analysis of the microstructures per se. The examination that used the scanner proved to be easier to implement, although it lacks of reliable results. The development of investigations concerning the application of histology in age at death estimation is an urgent and fundamental process, since there are empirically fewer studies in the area when compared to macroscopic approach. Thus, in spite of the results we think that a path was opened to the enlargement of future studies that use histology as a tool for age estimation in a Portuguese sample

Hydrogen-terminated detonation nanodiamond:impedance spectroscopy and thermal stability studies

In this paper, we investigated the effect of hydrogen termination on the electrical properties and impedance spectra of detonation nanodiamond. The impedance spectra revealed that the hydrogen-termination process increases the electrical conductivity by four orders of magnitude at room temperature. An equivalent circuit has been proposed to correlate with the conduction mechanism. Arrhenius plot showed that there were two different activation energy levels located at 0.089 eV and 0.63 eV between 50 °C and 400 °C. The possible physical mechanism corresponding to these activation energy levels has been discussed. Hydrogen-terminated detonation nanodiamond has been further annealed at different temperatures prior to FTIR and XPS measurements in order to understand their thermal stability. The results demonstrated that the surface oxidization occurred between 100 °C and 150 °C. However, the C-H bonds could partially survive when the temperature reaches 400 °C in air

Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs

Shallow Water ’06 : a joint acoustic propagation/nonlinear internal wave physics experiment

Author Posting. © Oceanography Society, 2007. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 20, 4 (2007): 156-167.Since the end of the Cold War, the US Navy has had an increasing interest in continental shelves and slopes as operational areas. To work in such areas requires a good understanding of ocean acoustics, coastal physical oceanography, and, in the modern era, autonomous underwater vehicle (AUV) operations

Capacity Building for a New Multicenter Network Within the ECHO IDeA States Pediatric Clinical Trials Network

Introduction: Research capacity building is a critical component of professional development for pediatrician scientists, yet this process has been elusive in the literature. The ECHO IDeA States Pediatric Clinical Trials Network (ISPCTN) seeks to implement pediatric trials across medically underserved and rural populations. A key component of achieving this objective is building pediatric research capacity, including enhancement of infrastructure and faculty development. This article presents findings from a site assessment inventory completed during the initial year of the ISPCTN. Methods: An assessment inventory was developed for surveying ISPCTN sites. The inventory captured site-level activities designed to increase clinical trial research capacity for pediatrician scientists and team members. The inventory findings were utilized by the ISPCTN Data Coordinating and Operations Center to construct training modules covering 3 broad domains: Faculty/coordinator development; Infrastructure; Trials/Research concept development. Results: Key lessons learned reveal substantial participation in the training modules, the importance of an inventory to guide the development of trainings, and recognizing local barriers to clinical trials research. Conclusions: Research networks that seek to implement successfully completed trials need to build capacity across and within the sites engaged. Our findings indicate that building research capacity is a multi-faceted endeavor, but likely necessary for sustainability of a unique network addressing high impact pediatric health problems. The ISPCTN emphasis on building and enhancing site capacity, including pediatrician scientists and team members, is critical to successful trial implementation/completion and the production of findings that enhance the lives of children and families

Shallow Water '06: A Joint Acoustic Propagation/Nonlinear Internal Wave Physics Experiment

Since the end of the Cold War, the US Navy has had an increasing interest in continental shelves and slopes as operational areas. To work in such areas requires a good understanding of ocean acoustics, coastal physical oceanography, and, in the modern era, autonomous underwater vehicle (AUV) operations. Each area presents challenges for both the scientist and the Navy. In physical oceanography, a complex interplay among winds, rivers, tides, and local bathymetry drives a non-stationary, shelf-break front and the nonlinear internal wave (NLIW) field. These strongly affect acoustic systems but are not adequately understood. A key oceanographic challenge is to model the fully four-dimensional ocean from the large-scale circulation down to fine scales, which include NLIW packets, internal tides, jets, and density fronts. Both Navy acoustics systems and Navy operations need the “local ocean weather” as well as the “ocean climate” as part of the routine forecast, but the former is not yet available.Keywords: Ocean acoustics, Coastal physical oceanography, AUV operations, Autonomous underwater vehicle operations, Acoustic propagatio

Miombo woodland under threat : Consequences for tree diversity and carbon storage

Agriculture is expanding rapidly in the miombo woodlands of sub-Saharan Africa. Clear felling results in the loss of species and ecosystem services. The remaining woodland is used as a vital support system for the farming communities, and the impact of this utilisation on biodiversity and ecosystem service provision is not clear. Understanding these effects will aid the development of effective, sustainable land management strategies for multiple outcomes, including biodiversity conservation and resource utilisation. This study provides new data on miombo woodland tree species diversity, structure and carbon storage from a 8766km2 landscape in south-western Tanzania, which is undergoing rapid conversion to tobacco cultivation.Human utilisation of the woodland was classified by ground surveys which recorded evidence of use (e.g. cut poles and timber, removal of bark and roots, access routes). Nine sites were surveyed and categorised into three groups: high, medium and low utilisation. To determine the effect of utilisation on the tree community stem density, diameter at breast height, tree species richness and carbon storage were recorded. In the low utilisation sites carbon storage was similar to that found in other miombo woodlands (28tHa-1), and the Shannon Wiener diversity score for tree species diversity was 3.44. However, in the high utilisation sites, tree species diversity (2.86) and carbon storage declined (14.6tHa-1). In areas of moderate utilisation diversity and carbon storage were maintained, but the structure of the woodland was affected, with a reduction of Class 1 (Diameter at Breast Height (DBH)<10cm) stems, demonstrating low recruitment which leads to a reduction in sustainability. Tree species richness and abundance demonstrated an intermediate disturbance effect in relation to utilisation, with highest levels at medium utilisation sites.Key miombo woodland species from the subfamily Caesalpinioideae in the two genera Brachystegia and Julbernardia were present in all sites, but the frequency of Brachystegia species declined by 60% from low to high utilisation. The IUCN near-threatened timber species Pterocarpus angolensis, highly protected in Tanzania, was harvested throughout the study site, and the majority of trees recorded were immature (DBH. ≤. 20. cm), suggesting that it is commercially extinct for the foreseeable future.These findings illustrate that in miombo woodlands with low to medium utilisation levels key miombo species are retained, and tree species diversity and carbon storage remains optimal. Sustainable land management plans need to regulate utilisation within miombo landscapes and retain areas of woodland. This will ensure their long term viability, and continue to support the 100. million people who are reliant on miombo woodlands for their goods and services