Abiotic modulation of Spartina maritima photobiology in different latitudinal populations

Spartina maritima has a very wide distribution in the northern hemisphere salt marshes crossing a wide variety of climatic environments. Therefore, it is not strange that some differences arise when observing the photosynthetic mechanisms of different populations inhabiting different latitudes. During this study it could be observed that climate is the most important factor controlling the photosynthetic traits of different populations distributed along a climatic gradient, namely the air temperature, humidity and light environment. Also some sediment physicochemical parameters such as pH and pore water salinity showed important influences driving the photosynthetic mechanisms in S. maritima. Furthermore S. maritima is one of the most abundant halophytes colonizing the Portuguese salt marshes. These facts have greater importance if one considers the large abundance of this halophytic species and how climate change will affect their metabolism and thus the ecosystem services provided by this species to the estuarine system.The authors would like to thank to the “ Fundação para a Ciência e Tecnologia (FCT)” for funding the research in the Centre of Oceanography throughout the project PEst-OE/MAR/UI0199/2011 and this specific work throughout the projects ECOSAM (PTDC/ AAC-CLI/104085/2008) and 3M RECITAL (LTER/BIA-BEC/0019/ 2009). B. Duarte investigation was supported by FCT throughout a PhD grant (SFRH/BD/75951/2011)

Production system of organic orange and its implications: Study in the SOS site Agroecological, Northeast of Pará

The organic production of produce in Brazil has been increasing very year due higher demand for more health food, and many farmers are migrating to these concept of food production. Therefore, the aim of this study is to understand the philosophic concept, as well as doing a description and analyzing the implications of the production system of organic orange. The research was done at Sítio SOS Agroecológico, localized in the city of CapitãoPoço, northeast of Pará. The qualitative exploratory research was done with the owner of the area, who is also a producer of organic orange, through, mainly, visits, semi structured surveys, transect walks in the area, and photographic records. The production of the site is considered adequate; their main market are organic fairs and big supermarkets; however, price and logistic are the main obstacles, besides the certification, where in Brazil is still an onerous process. The production system of Sitio SOS shows certain similarities with the concept of biologic and natural agriculture since both systems goals are the reduction of the rural producer costs, the use of alternative products and/or natural available on the property

Biomassa aérea e estimativa do carbono orgânico em Agrossistema do coqueiro (Cocus nucifera, L.) anão verde irrigado

Objetivou-se com o presente trabalho estimar os quantitativos da biomassa verde e seca da parte aérea do coqueiro e o estoque de carbono acumulados nos respectivos compartimentos. Buscou-se ainda verificar se esta variável pode ser utilizada como indicador consistente de sustentabilidade, de modo a oferecer uma contribuição direta aos estudos nesta área. A avaliação do estoque de carbono imobilizado é importante não apenas porque a cultura do coqueiro irrigado em Sousa/PB é relevante do ponto de vista socioeconômico, mas também por essa cultura ser a opção preferencial de cultivo e apresentar uma tendência à expansão na região. Para obtenção das amostras foram previamente selecionadas três planas representativas da população, as quais foram derrubadas e em seguida determinadas as biomassas frescas totais das diversas partes aéreas e retirados às respectivas amostras para determinar a biomassa seca. Na sequência aplicando-se o fator de conversão 0,48 para palmeiras encontrou-se o teor de carbono imobilizado total de cada árvore e de seus diversos compartimentos. Em seguida, por estimativa, determinou-se a biomassa fresca e seca total e o teor de carbono imobilizado do ecossistema em estudo. Dos resultados conclui-se que o estipe e as folhas verdes concentram a maior quantidade de carbono imobilizado da planta. O cultivo do coqueiro anão verde irrigado constitui-se em um importante mecanismo de imobilizar carbono, propiciando o estoque de 22.648 kg de carbono por hectare, na biomassa aérea

Interdependence between training and magnetization reversal in granular Co-CoO exchange bias systems

The interdependence between training and magnetization reversal in granular Co-CoO exchange bias (EB) systems prepared byOion implantation inCo thin films is demonstrated by polarized neutron reflectometry. While high-fluence O-implanted thin films show reduced relative training values and no asymmetry in magnetization reversal (all reversals take place by domain wall nucleation and motion), low-fluence O ion implantation results in an increased relative training and a magnetization reversal asymmetry between the first descending and the first ascending branches. Whereas the untrained decreasing field reversal occurs mainly by domain wall nucleation and motion, traces of a domain rotation contribution are evidenced in the increasing field reversal. This is explained by the evolution of the CoO structure and the contribution of the out-of-plane magnetization with ion implantation. The amount of incorporated O, which determines the threshold between both behaviors, is around 20 at.%. This reveals that the interdependence between training and magnetization reversal is insensitive to the morphology of the constituents (i.e., granular or layered), indicating that this is an intrinsic EB effect, which can be conveniently tailored by the interplay between the intrinsic properties of the investigated materials and ion implantation

Results of the third Marine Ice Sheet Model Intercomparison Project (MISMIP+)

We present the result of the third Marine Ice Sheet Model Intercomparison Project, MISMIP+. MISMIP+ is intended to be a benchmark for ice-flow models which include fast sliding marine ice streams and floating ice shelves and in particular a treatment of viscous stress that is sufficient to model buttressing, where upstream ice flow is restrained by a downstream ice shelf. A set of idealized experiments first tests that models are able to maintain a steady state with the grounding line located on a retrograde slope due to buttressing and then explore scenarios where a reduction in that buttressing causes ice stream acceleration, thinning, and grounding line retreat. The majority of participating models passed the first test and then produced similar responses to the loss of buttressing. We find that the most important distinction between models in this particular type of simulation is in the treatment of sliding at the bed, with other distinctions - notably the difference between the simpler and more complete treatments of englacial stress but also the differences between numerical methods - taking a secondary role. © 2020 Wolters Kluwer Medknow Publications. All rights reserved

Results of the third Marine Ice Sheet Model Intercomparison Project (MISMIP+)

We present the result of the third Marine Ice Sheet Model Intercomparison Project, MISMIP+. MISMIP+ is intended to be a benchmark for ice-flow models which include fast sliding marine ice streams and floating ice shelves and in particular a treatment of viscous stress that is sufficient to model buttressing, where upstream ice flow is restrained by a downstream ice shelf. A set of idealized experiments first tests that models are able to maintain a steady state with the grounding line located on a retrograde slope due to buttressing and then explore scenarios where a reduction in that buttressing causes ice stream acceleration, thinning, and grounding line retreat. The majority of participating models passed the first test and then produced similar responses to the loss of buttressing. We find that the most important distinction between models in this particular type of simulation is in the treatment of sliding at the bed, with other distinctions – notably the difference between the simpler and more complete treatments of englacial stress but also the differences between numerical methods – taking a secondary role

Landscape dynamics and diversification of the megadiverse South American freshwater fish fauna

Landscape dynamics are widely thought to govern the tempo and mode of continental radiations, yet the effects of river network rearrangements on dispersal and lineage diversification remain poorly understood. We integrated an unprecedented occurrence dataset of 4,967 species with a newly compiled, time-calibrated phylogeny of South American freshwater fishes—the most species-rich continental vertebrate fauna on Earth—to track the evolutionary processes associated with hydrogeographic events over 100 Ma. Net lineage diversification was heterogeneous through time, across space, and among clades. Five abrupt shifts in net diversification rates occurred during the Paleogene and Miocene (between 30 and 7 Ma) in association with major landscape evolution events. Net diversification accelerated from the Miocene to the Recent (c. 20 to 0 Ma), with Western Amazonia having the highest rates of in situ diversification, which led to it being an important source of species dispersing to other regions. All regional biotic interchanges were associated with documented hydrogeographic events and the formation of biogeographic corridors, including the Early Miocene (c. 23 to 16 Ma) uplift of the Serra do Mar and Serra da Mantiqueira and the Late Miocene (c. 10 Ma) uplift of the Northern Andes and associated formation of the modern transcontinental Amazon River. The combination of high diversification rates and extensive biotic interchange associated with Western Amazonia yielded its extraordinary contemporary richness and phylogenetic endemism. Our results support the hypothesis that landscape dynamics, which shaped the history of drainage basin connections, strongly affected the assembly and diversification of basin-wide fish fauna

Determinants of reef fish assemblages in tropical Oceanic islands

Diversity patterns are determined by biogeographic, energetic, and anthropogenic factors, yet few studies have combined them into a large‐scale framework in order to decouple and compare their relative effects on fish faunas. Using an empirical dataset derived from 1527 underwater visual censuses (UVC) at 18 oceanic islands (five different marine provinces), we determined the relative influence of such factors on reef fish species richness, functional dispersion, density and biomass estimated from each UVC unit. Species richness presented low variation but was high at large island sites. High functional dispersion, density, and biomass were found at islands with large local species pool and distance from nearest reef. Primary productivity positively affected fish richness, density and biomass confirming that more productive areas support larger populations, and higher biomass and richness on oceanic islands. Islands densely populated by humans had lower fish species richness and biomass reflecting anthropogenic effects. Species richness, functional dispersion, and biomass were positively related to distance from the mainland. Overall, species richness and fish density were mainly influenced by biogeographical and energetic factors, whereas functional dispersion and biomass were strongly influenced by anthropogenic factors. Our results extend previous hypotheses for different assemblage metrics estimated from empirical data and confirm the negative impact of humans on fish assemblages, highlighting the need for conservation of oceanic islands.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Rabdomiólise em militares: uma missão de reconhecimento para prevenção.

O treinamento físico regular faz parte do cotidiano militar, com intuito de aprimorar competências físicas essenciais para tarefas de combate. No entanto, quando executado de forma extenuante ou desenvolvido em condições climáticas adversas pode ocasionar o desenvolvimento da rabdomiólise por esforço físico. A rabdomiólise por esforço físico é definida como uma síndrome decorrente da necrose das células musculares, com sintomas variáveis, como dor muscular, fraqueza e aumento plasmático de enzimas musculares. A severidade da rabdomiólise por esforço físico varia individualmente, porém, pode se tornar clinicamente relevante, contribuindo para a hospitalização, insuficiência renal aguda, incapacidade permanente ou óbito. Sendo assim, o objetivo desta revisão narrativa é apresentar possíveis causas e fatores de risco para rabdomiólise, discutir sua fisiopatologia, seus possíveis diagnósticos e suas principais complicações, enfatizando o contexto militar

Didactic Sequence for Teaching Exponential Function

This paper presents a methodological proposal for the teaching of exponential function, resulting from the application of a didactic sequence involving exponential function, where evidence of learning and the consolidation and application of mathematical concepts in problem solving were identified and analyzed. The Didactic Engineering of Michèle Artigue (1988) was used as a research methodology. As theoretical contributions that guided and enabled the development of the research, we chose the use of Mathematical Investigation in the classroom; Didactic Sequence in the conception of Zabala (1999); the Articulated Units of Conceptual Reconstruction proposed by Cabral (2017) and assumptions of Vygotsky\u27s theory. A didactic sequence composed of five UARC\u27s was elaborated to work the exponential function, with a view to minimizing the difficulties naturally imposed by the content to be explained. Microgenetic analysis of verbal interactions between teacher and students was used to analyze the results of the application. The results show that the students participating in the experiment showed evidence of learning, recorded during the process, and began to have a good understanding of the concepts and properties related to the topic, in addition to a good performance in carrying out the activities, facts that corroborate the potential of the didactic sequence proposed herein