Hacia una administración consensuada de los recursos hídricos en ecociudades / Towards a consensus management of water resources in ecocities

La administración de los recursos hídricos es un tema de suma discusión ya que de ella depende la construcción de una ciudad sustentable en su agenda, gestión y participación. Empero, las políticas públicas relativas al abastecimiento de agua parecen estar centradas en una oferta desmedida ya no por la disponibilidad ni el consumo, sino por la información que los medios difunden acerca de una fuente de abastecimientoo conflicto entre autoridades y usuarios. En este sentido, es menester revisar los conceptos de oportunidades, capacidades, responsabilidades, habitus y espacialidades para discutir su vinculación con otros tales como encuadre, agenda o sustentabilidad. En el marco de la ciudad sustentable, tal ejercicio, permitirá anticipar la relación existente entre autoridades y usuarios en referencia a los medios de comunicación. Precisamente, la administración sería sustentable si el sistema de tarifas incluyera los conceptos que explican las relaciones entre los actores políticos, mediáticos y civiles implicados.

The management of water resources is subject to a payment system from which the state regulates public service water supply. These are rates that promote or restrict water consumption as water availability, the cost of extraction, treatment and distribution, or the degree of local human development. In either case the authorities determine the supply and demand assuming that civil society will adjust their life styles to public policy. In this sense, the media spread information that may be consistent or not the tariff policy and supply, however as the information is disseminated to the social sectors, a phenomenon known as emerging public agenda. It is the construction of public opinion on the evaluation of public policies and the inclusion of issues management for the sustainability of water resources. This is how the public agenda on water supply is limited to two axes: saving or waste of water resources. In the first case, the increase of tariffs favors an austere life in the vulnerable, marginalized and excluded. In the second case, the rates encourage wasteful life style in those social groups with higher incomes. Indeed, public policies for billing system generate a gap between the social sectors. It is therefore required to discuss other psychological factors as setting an agenda for the management of water resources is shaped not only by authorities but by users of public services. Given that the right to the city means access to resources, citizenship as a user of urban services, is a co-participant and co-responsible for water conservation for future generations. In the context of sustainable cities, government decisions are carried out considering not only the freedoms, opportunities, capabilities and responsibilities of users, it is also necessary to analyze their influence processes concerning compliance, obedience and innovation that derived from a schedule and fare system of water service. In a situation of scarcity, the majority influence has been studied from hoarding water while in the minority influence has been investigated from reuse. Both phenomena impact people's opinions because those who inhabit the periphery of cities are forced to kidnap pipes, boycott installations confront its authorities, or have developed styles of trust and cooperation that allow them to survive droughts or floods. Consequently, the assessment of water supply and pricing policy is determined by lifestyle and those put forth by these psychological processes. This means that the establishment of a public agenda includes issues such as influence, identity, reliability, entrepreneurship, social capital, sense of community, social representations, habitus, and fields of power, attitudes, beliefs, perceptions, skills, motives, decisions and behaviors. The elucidation of the relationship of each of these elements will anticipate the impact of public policies on current and future civil spheres, as well as public participation in the conservation of water resources, the public poured in social networks and their impact on the dissemination of media. Indeed, the objective of this work lies in the presentation, analysis and discussion of the relationship between users and public administrators in situations of irregular water supply and tariff increases. The media disseminated information about a source of supply or conflict between authorities and users. In this sense, it is necessary to review the concepts of opportunity, skills, responsibilities, habitus and spatialities to discuss their relationship with others such as framing, book or sustainability. As part of the sustainable city, this year, will anticipate the relationship between authorities and users in reference to the media. Indeed, the administration would be sustainable if the fare system to include concepts that explain the relationships between political, media and civil actors.

Respostas agudas de pressão arterial e variabilidade da frequência cardíaca são dependentes do volume total do exercício aeróbio em adultos saudáveis / Acute blood pressure and heart rate variability responses in healthy adults are dependent on the total volume of aerobic exercise

A hipotensão pós-exercício (HPE) é um fenômeno de relevância clínica, mas dúvidas persistem no tocante ao efeito do modo e da forma de execução (contínua vs. acumulada) do exercício aeróbio para sua manifestação, bem como o papel do controle autonômico cardíaco como mecanismo fisiológico associado à HPE. Assim, a presente tese objetivou: a) investigar a HPE induzida por sessões aeróbias de exercício isocalórico contínuo e acumulado; b) comparar as respostas de pressão arterial sistólica (PAS) e diastólica (PAD) após teste cardiopulmonar de exercício máximo (TCPE) em três modalidades; c) verificar a influência do modo de exercício e do controle autonômico cardíaco em repouso sobre a reativação vagal após TCPE. No primeiro estudo, 10 homens saudáveis (idade: 27,6 ± 3,5 anos) realizaram TCPEs de corrida e ciclismo para medida do consumo de oxigênio de pico (VO2pico) e sessões contínuas (400 kcal) e acumuladas (2 x 200 kcal) de corrida e ciclismo à 75%VO2reserva. A PAS e PAD reduziram similarmente após exercício contínuo e acumulado (4,6 ± 2,3 vs. 5,2 ± 2,3 mmHg, 2,6 ± 2,5 vs. 3,6 ± 2,5 mmHg, respectivamente, P > 0,05). Porém, a corrida provocou maior declínio na PAS do que o ciclismo (P < 0.05). A atividade simpática (componente de baixa frequência, LF) e parassimpática (componente de alta frequência, HF) aumentou (P < 0,001) e diminuiu (P < 0,001) em relação à sessão controle, elevando o balanço simpato-vagal (razão LF:HF) (P < 0,001) que foi inversamente correlacionado ao ΔPAS e ΔPAD (r = -0,41 a -0,70; P < 0.05). No segundo e terceiro estudos, 20 homens saudáveis (idade: 21.2 ± 3.0 anos) realizaram três TCPEs (ciclismo, caminhada e corrida). No segundo estudo, investigou-se a resposta aguda da PA, débito cardíaco (Q), resistência vascular periférica (RVP), sensibilidade do barorreflexo arterial (SBR), variabilidade da frequência cardíaca (VFC) e dispêndio energético durante 60 min após os TCPEs e sessão controle...

Postexercise hypotension (PEH) is a phenomenon of clinical relevance, but doubts persist regarding the effect of the mode and manner of execution (continuous vs. cumulative) of aerobic exercise for its manifestation, as well as the role of cardiac autonomic control as physiological mechanisms associated with PEH. Thus, this thesis aimed to: a) investigate the PEH elicited by isocaloric bouts of continuous and accumulative aerobic exercise; b) to compare the acute responses of systolic (SBP) and diastolic blood pressure (DBP) after maximal cardiopulmonary exercise tests (CPET) performed using three exercise modalities; and c) to determine the influence of exercise mode and cardiac autonomic control at rest on the vagal reactivation after CPET. In the first study, ten healthy men (age: 27.6 ± 3.5 yrs) performed maximal CPETs to determine the peak oxygen uptake (VO2peak), and continuous (400 kcal) and accumulated (2 x 200 kcal) exercise bouts of running and cycling at 75% VO2reserve. The SBP and DBP decreased similarly after continuous and accumulated exercise (4.6 ± 2.3 vs. 5.2 ± 2.3 mmHg, 2.6 ± 2.5 vs. 3.6 ± 2.5 mmHg, respectively, P > 0.05). However, running elicited greater SBP reductions than cycling (P < 0.05). The sympathetic (low frequency component, LF) and parasympathetic (high frequency component, HF) activity increased (P < 0.001) and decreased (P < 0.001) from baseline, increasing the sympathovagal balance (LF:HF ratio) (P < 0.001) that was inversely related to ΔSBP and ΔDBP (r = -0.41 to -0.70; P < 0.05). In the second and third studies, 20 healthy men (age: 21.2 ± 3.0 yrs) performed three CPETs (cycling, walking and running). The second study investigated the acute response of BP, cardiac output (Q), peripheral vascular resistance (PVR), spontaneous baroreflex sensitivity (SBR), heart rate variability (HRV) and energy expenditure during 60 min after exercise and a control session...

Comparison of energy cost between genders during treadmill walking at a self-selected pace / Comparação do gasto energético entre os gêneros durante a caminhada na esteira em ritmo autosselecionado

The purpose of this study was to compare the energy cost between genders during treadmill walking at self-selected pace; and to verify if the energy cost achieve the values recommended for weight maintenance or loss proposed by the American College of Sports Medicine (ACSM). Seventeen men and seventeen women, mean age of 23.32 ± 3.06 years, undertaken two experimental sessions: (I) anthropometric measurements and a load-incremental maximum test; and, (II) a 20-min walking test at self-selected pace on treadmill. Men showed a greater energy cost than women (146.18 ± 47.66 and 100.86 ± 17.04 kcal, respectively). This difference was maintained after adjust by body weight (2.2 ± 0.5 and 1.7 ± 0.2 kcal kg-1, respectively). The greater energy cost found in men can be explained by the self-selected treadmill speed that lead to a greater O2 in men. However, the exercise intensity selected by both genders did not elicit an effective energy cost that can promote weight maintenance or loss. Nonetheless, if participants performed a longer walking (> 20 minutes), they probably would achieve the energy cost recommended by the ACSM guidelines.

O objetivo do presente estudo foi comparar o gasto energético entre os gêneros durante a caminhada na esteira em ritmo auto-selecionado e verificar se a intensidade que os sujeitos buscam caminhar promove um dispêndio energético dentro do recomendado para a manutenção e/ou redução do peso corporal conforme proposto pelas diretrizes do ACSM. Participaram 17 homens e 17 mulheres com média de idade de 23,32 ± 3,06 anos, submetidos a duas sessões experimentais: (I) avaliação antropométrica e teste incremental máximo, e (II) um teste de 20 minutos de caminhada na esteira em ritmo auto-selecionado. Os homens apresentaram um gasto energético superior ao das mulheres (146,18 ± 47,66 e 100,86 ± 17,04 kcal, respectivamente). Essas diferenças persistiram após correção da massa corporal (2,2 ± 0,5 e 1,7 ± 0,2 kcal kg-1, respectivamente). Pode-se concluir que o maior gasto energético encontrado nos homens, foi decorrente da velocidade de caminhada auto-selecionada, proporcionando um O2 superior. Contudo a intensidade de caminhada selecionada por ambos os gêneros não foi suficiente para propiciar um gasto energético considerado efetivo para manutenção e/ou redução do peso corporal. Entretanto, é possível especular que se a atividade fosse realizda por um periodo mais longo (> 20 minutos), os indivíduos poderiam atingir as diretrizes propostas pelo ACSM.

Respostas metabólicas ao treinamento de força: uma ênfase no dispêndio energético / Metabolic responses to strength training: an emphasis on energy expenditure

O presente estudo revisa os resultados encontrados, até então, na literatura, relativos ao dispêndio energético (DE) no treino de força (TF). Para tanto, foi realizado um levantamento bibliográfico nas bases de dados Medline e Sport Discus, utilizando as palavras-chave: strength training, energy expenditure e excess post exercise oxygen consumption (EPOC). Os estudos analisados referem que protocolos de TF que envolvam exercícios para grandes grupos musculares, com grandes intensidades e volumes de treinamento, e menores intervalos de recuperação entre séries e exercícios são os que apresentam maior impacto metabólico na sessão de treino. Essas mesmas variáveis também demonstram interferir na magnitude e na duração do EPOC.

The present study reviews the results reported in the literature regarding energy expenditure in strength training (ST). For this purpose, a search was conducted in the Medline and Sport Discus databases using the following key words: strength training, energy expenditure, and excess post-exercise oxygen consumption (EPOC). The studies analyzed report that ST protocols involving exercises for the major muscle groups characterized by high-intensity and high-volume training and low resting intervals between sets and exercises have a greater metabolic impact on ST. These variables also interfere with the magnitude and duration of EPOC.

Desempenho agronômico e econômico do milho irrigado em sucessão a espécies invernais de cobertura de solo e/ou para produção de grãos / Agronomic and economic performance of maize irrigated in succession to winter cover crops and/or to species for grain production

As espécies de cobertura de solo no inverno melhoram as características de solo, podendo apresentar também vantagens econômicas. Assim, é importante introduzir espécies de inverno que, além de palha, possam produzir grãos para aumentar a rentabilidade e a sustentabilidade da atividade agrícola. O objetivo desta pesquisa foi avaliar, em três estações de crescimento, os desempenhos agronômico e econômico do milho irrigado em sucessão a espécies invernais para cobertura de solo e/ou para produção de grãos, cultivado sob dois níveis de nitrogênio (N) em cobertura. A pesquisa foi conduzida nas estações de crescimento 2003/04, 2004/05 e 2005/06, no município de Eldorado do Sul, RS. Nos três anos, os tratamentos constaram do cultivo do milho irrigado em sucessão a cinco espécies de inverno e ao pousio, como testemunha. O custo de produção do milho em sucessão à ervilhaca comum é menor do que o da aveia preta e do nabo forrageiro. Das espécies invernais de cobertura de solo e de produção de grãos, a margem bruta obtida com o trigo é maior que a com a aveia branca. As vantagens econômicas do uso do nabo forrageiro e da ervilhaca comum como culturas antecessoras ao milho irrigado em relação às espécies poáceas apenas ocorrem sob baixos níveis de N aplicados em cobertura no milho.

The growing of winter crop species results in benefits on soil characteristics, and can present economic advantages. Thus, it is important to introduce winter species that, besides straw, produce grains to increase the performance and the sustentability of agricultural activity. The objective of this research was to evaluate, in three growing seasons, the agronomic and economic performance of maize crop grown in succession to five winter cover crops and/or for grain production, cultivated under two rates of side dressing N fertilization. The experiment was carried out in the growing seasons of 2003/04, 2004/05 and 2005/06, in the state of Rio Grande do Sul, Brazil. In the three years, the treatments consisted of irrigated maize crop grown in succession to five winter cover crops species and to a control without cover crop. The maize cost production in succession to common vetch is lower than in succession to black oat and to wild radish. Comparing the winter cover crops for grain production, the gross income was higher when wheat was grown in relation to oat. The economic advantages of the use of wild radish and common vetch as previous crops to irrigated maize in relation to the poaceae species are only evident under conditions of low N availability in the soil.