399 resultados para antecedent wetness
Resumo:
Northern white cedar (Thuja occidentalis L.) (NWC) swamps are valuable both commercially and ecologically. Unfortunately, many NWC swamps are degraded and information about them is not abundant. Especially there have been no definitive studies about mosses in northern white cedar swamps and how they react to disturbances. Mosses are sensitive to changes in their environment and thus they could be used to assess ecosystem conditions of NWC swamps. The objective of this study was to determine if mosses could be used to asses conditions in NWC swamps and if there are differences between moss communities in disturbed and undisturbed sites. Seventeen sample plots were taken from 12 disturbed and undisturbed sites around upper Michigan and northern Minnesota in the summer of 2012. All mosses occurring on the plots were identified and several associated environmental parameters were measured. The main environmental conditions affecting moss communities were identified with non-metric multidimensional scaling (NMS). Multiple response permutation procedures (MRPP) were run to ascertain if there were significant differences in community composition between disturbances. Indicator species analysis was then done to identify species that are related to different types of disturbances. A one-way ANOVA was used to check for significant differences between species richness and moss cover of undisturbed and disturbed sites. Over all sixty-two moss species were identified. The results indicate that there was no significant difference in species richness or moss cover between disturbed and undisturbed sites. However, moss community composition was affected by disturbance and strongly divided by a wetness gradient. Dicranum fuscescens was found to indicate undisturbed conditions. Calliergon cordifolium and Climacium dendroides indicated disturbed sites with wet conditions. Brotherella recurvans and Eurhynchium pulchellum indicated swamps with other disturbances.
Resumo:
It has been claimed that employee engagement can harness public service motivation in ways that lead to better improve functioning and positive organizational outcomes, and can help address the increasingly complex challenges associated with public service in an era of austerity. Despite this, there has not yet been a systematic review of the literature that would enable researchers to understand more about the antecedent factors and the outcomes of engagement in the public sector. To address this issue, we undertook a systematic narrative synthesis of the empirical research on engagement that yielded 5111 published studies, of which just 59 were conducted in public sector settings and met our inclusion criteria. Studies generally found that motivational features of jobs (such as autonomy), group (such as social support), management (such as leader consideration), and organizations (such as voice mechanisms) as well as psychological resources were key antecedents of engagement within the public sector; and that engagement was associated with positive employee health/morale and enhanced performance behaviors. The evidence was far from conclusive, suggesting a need for much more rigorous research focused on the specific challenges of public sector settings. We make recommendations for further research on this important topic, particularly with regards to understanding the connection between public service motivation and engagement and the need to examine engagement across different public sector/service contexts.
Resumo:
Introducción: La implicación social dentro de la problemática ambiental, establece una relación causal entre hábitos e impacto ambiental; aspectos del comportamiento humano tales como la conveniencia, familiaridad, presión social y actitud, nos permiten realizar un acercamiento acerca de la decisión de reciclar o no en un hogar. Objetivo: identificar los factores ambientales asociados con el manejo de residuos domésticos entre los miembros de una comunidad residencial en la ciudad de Bogotá. Materiales y métodos: Se realizó un estudio transversal realizado a 200 personas de una comunidad residencial. La evaluación de la conducta pro-ambiental se llevó a cabo por medio de la utilización de la Escala del Comportamiento Pro-ambiental desarrollada por Corral-Verdugo unida a la escala de Reciclaje de Sidique. Para el tratamiento estadístico se empleó el análisis de regresión lineal múltiple. Resultados: La mayoría de los encuestados fueron hombres (55%), con una mediana de edad de 37,5 años. Más de la mitad tenía por lo menos formación en pregrado (53%), el 55,5% contaban con un empleo al momento de la entrevista, cerca del 50% de las personas refirieron tener casa propia y la mediana del tamaño de las mismas fue de 80 m2. De los aspectos sociodemográficos, el tipo de vivienda, sexo y edad, estuvieron relacionados con los factores ambientales pro reciclaje. Mientras que las conductas proambientales relacionadas fueron: altruismo, frugalidad, conducta ecológica general, indignación y aprecio por la naturaleza. Conclusiones: Las conductas proambientales Altruismo, Frugalidad, Conducta Ecológica, Indignación y Aprecio por lo natural, están relacionadas con la intención de reciclar. Para futuras investigaciones es necesario constatar la realización del comportamiento proambiental, para aseverar de manera irrebatible que las dimensiones analizadas pueden soportar una acción real y no un auto reporte de una conducta.
Resumo:
Se exponen algunos antecedentes y diagnósticos a escala regional. Se precisan desigualdades regionales, a partir de la identificación de una competencia urbano-regional, contrastes socio-económicos profundos entre San Isidro del General y, por ejemplo, Buenos Aires. También se revisan los esfuerzos de planificación efectuados y tipos de proyectos sectoriales y específicos propuestos a escala urbano-regional. SUMMARY Some antecedent and diagnostic studies are explained at a regional level. Regional inequalities are determined, beginning with the identification of urban-regional struggles. Profound social-economic contrasts between San Isidro de El General and Buenos Aires, for example, are also identified. Planning efforts that have been carried out in the past and the types of sectorial and the specific projects proposed at an urban-regional level are also revised. RESUME On décrit quelques antécédents et diagnostiques à l’échelle régionale. On remarque les inégalités régionales, parmi l’indentification d’une concurrence urbain-régionale, différentiation socio-économique profonde entre San Isidro de El General et Buenos Aires. Aussi, on étudie les efforts de planification qu’ont été faites, tel comme les types de projets sectoriels et spécifiques dessinés á l’échelle urbaine-régionale.
Resumo:
Canopy and aerodynamic conductances (gC and gA) are two of the key land surface biophysical variables that control the land surface response of land surface schemes in climate models. Their representation is crucial for predicting transpiration (λET) and evaporation (λEE) flux components of the terrestrial latent heat flux (λE), which has important implications for global climate change and water resource management. By physical integration of radiometric surface temperature (TR) into an integrated framework of the Penman?Monteith and Shuttleworth?Wallace models, we present a novel approach to directly quantify the canopy-scale biophysical controls on λET and λEE over multiple plant functional types (PFTs) in the Amazon Basin. Combining data from six LBA (Large-scale Biosphere-Atmosphere Experiment in Amazonia) eddy covariance tower sites and a TR-driven physically based modeling approach, we identified the canopy-scale feedback-response mechanism between gC, λET, and atmospheric vapor pressure deficit (DA), without using any leaf-scale empirical parameterizations for the modeling. The TR-based model shows minor biophysical control on λET during the wet (rainy) seasons where λET becomes predominantly radiation driven and net radiation (RN) determines 75 to 80 % of the variances of λET. However, biophysical control on λET is dramatically increased during the dry seasons, and particularly the 2005 drought year, explaining 50 to 65 % of the variances of λET, and indicates λET to be substantially soil moisture driven during the rainfall deficit phase. Despite substantial differences in gA between forests and pastures, very similar canopy?atmosphere "coupling" was found in these two biomes due to soil moisture-induced decrease in gC in the pasture. This revealed the pragmatic aspect of the TR-driven model behavior that exhibits a high sensitivity of gC to per unit change in wetness as opposed to gA that is marginally sensitive to surface wetness variability. Our results reveal the occurrence of a significant hysteresis between λET and gC during the dry season for the pasture sites, which is attributed to relatively low soil water availability as compared to the rainforests, likely due to differences in rooting depth between the two systems. Evaporation was significantly influenced by gA for all the PFTs and across all wetness conditions. Our analytical framework logically captures the responses of gC and gA to changes in atmospheric radiation, DA, and surface radiometric temperature, and thus appears to be promising for the improvement of existing land?surface?atmosphere exchange parameterizations across a range of spatial scales.
Resumo:
Canopy and aerodynamic conductances (gC and gA) are two of the key land surface biophysical variables that control the land surface response of land surface schemes in climate models. Their representation is crucial for predicting transpiration (?ET) and evaporation (?EE) flux components of the terrestrial latent heat flux (?E), which has important implications for global climate change and water resource management. By physical integration of radiometric surface temperature (TR) into an integrated framework of the Penman?Monteith and Shuttleworth?Wallace models, we present a novel approach to directly quantify the canopy-scale biophysical controls on ?ET and ?EE over multiple plant functional types (PFTs) in the Amazon Basin. Combining data from six LBA (Large-scale Biosphere-Atmosphere Experiment in Amazonia) eddy covariance tower sites and a TR-driven physically based modeling approach, we identified the canopy-scale feedback-response mechanism between gC, ?ET, and atmospheric vapor pressure deficit (DA), without using any leaf-scale empirical parameterizations for the modeling. The TR-based model shows minor biophysical control on ?ET during the wet (rainy) seasons where ?ET becomes predominantly radiation driven and net radiation (RN) determines 75 to 80?% of the variances of ?ET. However, biophysical control on ?ET is dramatically increased during the dry seasons, and particularly the 2005 drought year, explaining 50 to 65?% of the variances of ?ET, and indicates ?ET to be substantially soil moisture driven during the rainfall deficit phase. Despite substantial differences in gA between forests and pastures, very similar canopy?atmosphere "coupling" was found in these two biomes due to soil moisture-induced decrease in gC in the pasture. This revealed the pragmatic aspect of the TR-driven model behavior that exhibits a high sensitivity of gC to per unit change in wetness as opposed to gA that is marginally sensitive to surface wetness variability. Our results reveal the occurrence of a significant hysteresis between ?ET and gC during the dry season for the pasture sites, which is attributed to relatively low soil water availability as compared to the rainforests, likely due to differences in rooting depth between the two systems. Evaporation was significantly influenced by gA for all the PFTs and across all wetness conditions. Our analytical framework logically captures the responses of gC and gA to changes in atmospheric radiation, DA, and surface radiometric temperature, and thus appears to be promising for the improvement of existing land?surface?atmosphere exchange parameterizations across a range of spatial scales.
Resumo:
A partire dalla caduta di Costantinopoli (1453) il problema dell’espansionismo ottomano acquisì progressiva importanza negli equilibri politici europei, scandendo con momenti di tregua e ostilità i rapporti tra Ponente e Levante per i successivi due secoli. Le conseguenze di tali tensioni politiche si riversarono sulla ritrattistica dei principi europei, il cui nuovo ruolo di eroi antiturchi trovò espressione, coerentemente con la diffusa lettura del problema ottomano in un’ottica di comparatio temporum, nell’istituzione di parallelismi con figure d’eroi antecedenti, della storia o del mito. Tali immagini allegoriche principesche hanno costituito il soggetto del presente studio e sono state indagate attraverso tre focus su altrettanti contesti cronologici, compresi tra la presa turca della capitale dell’Impero bizantino e la riconquista cristiana di Tunisi (1535). La considerazione di questo arco temporale, meno indagato rispetto a cronologie successive, ha consentito di individuare e rendere ragione di alcune specificità iconografiche delle immagini allegoriche dei principi antiturchi: tra queste in primis è emerso un movimento oscillatorio tra il riuso di iconografie sacrali-cavalleresche, di matrice crociata, e l’impiego di un repertorio di modelli eroici antichi, elaborato ad hoc nel detto frangente storico-culturale, le cui origini sono state rintracciate negli scritti encomiastici ed esortativi degli umanisti italiani attivi nel secondo Quattrocento. I casi di studio presi in esame hanno inoltre conferito alla ricerca un carattere d’interesse anche in rapporto agli studi sulla ritrattistica d’identificazione, annoverando una serie di diverse forme di espressione visiva della comparazione eroica, delle quali il ritratto in veste eroica costituisce la manifestazione più compiuta. Sia sul frangente iconografico sia su quello tipologico, i risultati ottenuti della ricerca sono infine stati verificati, in sede di conclusioni, su un succinto corpus di opere esteso al tardo Cinquecento e al Seicento.
Resumo:
The study of the combined reforming (CR) process to produce synthesis gas (CO + H2) feeding Clean Biogas (CB, biogas in which the main pollutants have been removed) has been performed on Ni-based bimetallic catalysts promoted by small amounts of Rh or Cu, prepared by incipient wetness impregnation or coprecipitation of different precursors on mixed oxides Mg/Al/O obtained by calcination of hydrotalcite-type (Ht) coprecipitates. It has been observed as the formation of bimetallic particles promoted the catalytic activity and limited the deactivation phenomena, allowing to operate at lower temperature and feeding lower amounts of steam. By this way, it was possible to define the best promoter, to tune its amount and the formation of the bimetallic nanoparticles. Finally, it has been simulated the scale-up of the CR process to industrial level, evaluating the feasibility and economic degree by comparison with the industrially exploited Autothermal reforming (ATR) process, evidencing the possible scalability and the advantages at environmental and energetic level in comparison to the current reforming processes.
Resumo:
Finding the optimum location for placing a dam on a river is usually a complicated process which generally forces thousands of people to flee their homes because they will be inundated during the filling of the dam. Dams could also attract people living in the surrounding area after their construction. The goal of this research is to check for dam attractiveness for people by comparing growth rates of population density in surrounding areas after dam construction to those associated with the period antecedent to the dam construction. To this aim, 1859 dams across the United States of America and high-resolution population distribution from 1790 to 2010 are examined. By grouping dams as a function of their main purpose, water supply dams are found to be, as expected, the most attractive dams for people, with the biggest growth in population density. Irrigation dams are next, followed by hydroelectricity, flood control, Navigation, and finally Recreation dams. Fishery dams and dams for other uses suffered a decrease in population in the years after their construction. The regions with the greatest population growth were found approximately 40-45 km from the dam and at distances greater than 90 km, whereas the regions with the greatest population decline or only a modest gain were located within 10-15 km of the dam.