Shade is defined as the coolness and darkness caused by shelter from solar radiation. In freshwater, shade is most commonly provided by riparian vegetation, which can affect water quality through its effects on temperature and light. The purpose of this research was to explore riparian shade influences on (1) fish distribution along reservoir littorals and (2) diel water quality patterns. Sampling was conducted in shaded and non-shaded paired sites in Columbus Lake, Mississippi, U.S.A. Differences in species distribution revealed that, in general, clupeids and most centrarchids were better represented in unshaded sites, while percids were better represented in shaded sites. Diel cycles of water quality variables were measured in situ over 24-h periods with auto-samplers and assessed using trigonometric polynomial regression to describe daily cycles. Analysis of covariance revealed all water quality variables differed between sites and most also varied between shaded and unshaded sites and exhibited daily cycles.

No description available.

Tesis por compendio / [EN] DELLA proteins are plant-specific transcriptional regulators known to relay environmental information to the transcriptional networks to modulate growth and development accordingly. The view of DELLAs as signalling hubs is justified by two characteristics: first, they control the activity of a large number of transcriptional factors (TFs) and other transcriptional regulators through physical interaction; and, second, they are degraded by the 26S proteasome in response to the phytohormone gibberellin (GA), whose metabolism is very sensitive to environmental stimuli (e.g. light, temperature, salt stress). However, at least two observations indicate that this mechanistic framework is still incomplete: (i) warm temperature destabilizes the GA-insensitive DELLA rga-¿17, indicating that DELLAs cannot be destabilized only by changes in GA levels; and (ii) when found at the chromatin, DELLAs are localized not only in gene promoters, but also in gene bodies, suggesting that DELLAs may regulate transcription through interactions with proteins other than TFs. In this Thesis, we provide evidence that shows how a different E3 ubiquitin ligase controls the stability of DELLAs in a GA-independent manner, and how DELLAs regulate gene expression by directly interacting with the basal transcriptional machinery. In the first chapter, using a combination of genetic, physiological, and molecular approaches we demonstrate that DELLAs are targeted to proteolytic degradation by the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1). We show that COP1 interacts with the DELLAs GAI and RGA in vitro and in vivo, and that it promotes their polyubiquitination. We propose that COP1 represents a major pathway to degrade DELLAs in response to shade or to warm temperature. In the second chapter, we describe the interaction between DELLAs and the transcription elongation complex Polymerase-Associated Factor 1 (Paf1c). We show that Paf1c is required for the genome-wide deposition of monoubiquitinated H2B (H2Bub), a mark necessary for the progression of RNA polymerase II (RNAPII), and that this function is largely dependent on the presence of DELLAs. Likewise, impaired Paf1c or DELLA function results in a similar alteration in the accumulation and distribution of RNAPII in the Paf1c-target genes. We propose that DELLAs would exert this action by modulating the recruitment of Paf1c to the chromatin. These two new mechanisms underscore the importance of DELLAs as a central node in the environmental signalling network and should be considered in any potential application of DELLAs as biotechnological targets. / [ES] Las proteínas DELLA son reguladores transcripcionales específicos de plantas que transmiten información ambiental a las redes transcripcionales que modulan el crecimiento y el desarrollo. La propuesta de que las DELLAs actúan como "hubs" en redes de señalización se justifica por dos razones: primero, controlan la actividad de un gran número de factores de transcripción (FTs) y otros reguladores transcripcionales mediante interacción física; y segundo, son degradadas por el proteosoma 26S en respuesta a la fitohormona giberelina (GA), cuyo metabolismo es muy sensible a los estímulos ambientales (p. ej. luz, temperatura, estrés salino). Sin embargo, al menos dos observaciones sugieren que la información relativa a estos mecanismos no es completa: (i) las temperaturas altas desestabilizan incluso a rga-¿17, una versión de DELLA insensible a GAs, lo que indica que la estabilidad de las DELLAs no depende sólo de cambios en los niveles de GAs; y (ii) cuando se encuentran en la cromatina, las DELLAs no solo se posicionan en los promotores, sino también a lo largo de las regiones codificantes, lo que sugiere que las DELLAs podrían regular la transcripción mediante interacciones con otras proteínas diferentes a FTs. En esta Tesis, proporcionamos evidencia sobre una nueva E3 ubicuitina ligasa que controla la estabilidad de las DELLAs de una manera independiente a las GAs, y cómo las DELLA regulan la expresión génica interaccionando directamente con la maquinaria de transcripción basal. En el primer capítulo, usando una combinación de aproximaciones genéticas, fisiológicas y moleculares, demostramos que las DELLAs son marcadas para su degradación proteolítica por la E3 ubicuitina ligasa CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1). Mostramos que COP1 interacciona al menos con las DELLAs GAI y RGA in vitro e in vivo, y que promueve su poliubicuitinación. Proponemos que COP1 representa una vía importante de degradación de DELLAs en respuesta a sombra y temperaturas altas. En el segundo capítulo, describimos la interacción entre las DELLAs y el complejo de elongación transcripcional Polymerase-Associated Factor 1 (Paf1c). Mostramos que, como en animales, Paf1c se requiere para la deposición a nivel genómico de la H2B monoubiquitinada (H2Bub), una marca necesaria para la progresión de la RNA polimerasa II (RNAPII), y que esta función depende en gran medida de la presencia de DELLAs. Asimismo, la reducción de la función de las DELLAs provoca defectos equivalentes a los de la pérdida de función de Paf1c en cuanto a la acumulación y distribución de la RNAPII en los genes diana de Paf1c. Proponemos que las DELLAs podrían por tanto regular la transcripción modulando el reclutamiento de Paf1c a la cromatina. Estos nuevos mecanismos inciden en la importancia de las DELLAs como nodos centrales en las redes de señalización al ambiente y podrían ser considerados como dianas biotecnológicas en aproximaciones futuras. / [CA] Les proteïnes DELLA són reguladors transcripcionals específics de les plantes conegudes per transmetre informació mediambiental a les xarxes transcripcionals per modular el creixement i desenvolupament. La visió actual de DELLAs com a "hubs" de senyalització es justifica per dues característiques: en primer lloc, controlen l'activitat d'un gran nombre de factors transcripcionals (FTs) i d'altres reguladors transcripcionals mitjançant la interacció física; i, en segon lloc, es degraden pel proteosoma 26S en resposta a la fitohormona giberel.lina (GA), el metabolisme de la qual és molt sensible als estímuls ambientals (per exemple, la llum, la temperatura, l'estrès salí). No obstant això, almenys dues observacions indiquen que aquest marc mecanicista encara és incomplet: (i) la temperatura càlida desestabilitza la DELLA rga-¿17, que és insensible a GAs, indicant que les DELLA no es desestabilitzen només per canvis en els nivells d'aquesta fitohormona; i (ii) quan es troben a la cromatina, les DELLA no només es localitzen en els promotors dels gens, sinó també a la regió que es transcriu, cosa que suggereix que poden regular la transcripció mitjançant interaccions amb proteïnes diferents de FTs. En aquesta tesi, proporcionem evidències que mostren com una ubiquitina E3 lligasa diferent controla l'estabilitat de les proteïnes DELLA de manera independent de GAs, i com les DELLA regulen l'expressió gènica interactuant directament amb la maquinària transcripcional basal. En el primer capítol, mitjançant una combinació d'enfocaments genètics, fisiològics i moleculars, demostrem que les DELLA s'envien a la degradació proteolítica mitjançant la ubiquitina E3 lligasa CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1). Mostrem que la COP1 interacciona amb els DELLA GAI i RGA in vitro i in vivo, i que afavoreix la seva poliubiquitinació. Proposem que COP1 representa la via principal per degradar les DELLA en resposta a l'ombra o a la temperatura càlida. Al segon capítol, es descriu la interacció entre les DELLA i el complex d'allargament de transcripció Polymerase Associated Factor 1 (Paf1c). Mostrem que Paf1c es requereix per a la deposició a tot el genoma de H2B monoubiquitinada (H2Bub), una marca necessària per a la progressió de l'ARN Polimerasa II (RNAPII), i que aquesta funció depèn en gran part de la presència de DELLA. De la mateixa manera, quan la funció Paf1c o DELLA està deteriorada, es produeix una alteració similar en l'acumulació i distribució de RNAPII als gens diana de Paf1c. Proposem que les DELLA realitzen aquesta acció modulant el reclutament de Paf1c a la cromatina. Aquests dos nous mecanismes posen de manifest la importància de les proteïnes DELLA com a node central de la xarxa de senyalització ambiental i haurien de ser considerats en qualsevol aplicació potencial de DELLA com a objectius biotecnològics. / La realización de esta Tesis Doctoral ha sido posible gracias a un contrato predoctoral para la formación de doctores (BES-2014-068868) y a la ayuda a la movilidad predoctoral para la realización de estancias breves (EEBB-I-16-11070) del Ministerio de Economía y Competitividad, y a una beca EMBO Short-Term (number 8047). / Blanco Touriñán, N. (2020). New mechanisms of DELLA protein regulation and activity in Arabidopsis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149477 / TESIS / Compendio

No description available.

No description available.

Trees in silvopastures may provide forage-livestock systems with multiple goods and services, including shade, shelter, and browse. Reports of forage and animal productivity from these systems indicate that, in some cases, animal gains are similar or better despite lower forage yield. The relationship between grazing system, body temperature, grazing behavior, and animal performance was explored in this study. Black walnut and honeylocust-based silvopasture systems were compared with open pastures in a randomized complete block design (r = 3) over three summers. Pastures were rotationally stocked with 5-7 lambs depending on forage availability. Lambs were weighed every four weeks. Behavior measures were recorded within a replicate within a week, and these measures were taken sequentially within three experimental periods. Ewe lambs (n = 3) were equipped with a vaginal temperature sensor (3 days) and an audio recording device (1 day) to detect prehension events. Cameras documented lamb behavior every 60 seconds. Forage measurements taken with a rising plate meter indicated greater productivity in the honeylocust silvopasture (5020 ± 30 kg · ha⁻¹ ) compared to the open pasture (4930 ± 30 kg · ha⁻¹ ; P = 0.0281), though forage availability in the black walnut silvopastures (3560 ± 30 kg · ha⁻¹ ) was lower than within the other treatments (P < 0.0001). There was no difference in animal gains between systems (P ≥ 0.4813), though gains were highest in the honeylocust silvopastures (25.6 ± 3.4 kg · period⁻¹ ), followed by the gains of the black walnut silvopastures (22.3 ± 3.4 kg · period⁻¹ ), and the gains of the open pastures (22.2 ± 3.4 kg · period- 1 ). Lambs in silvopastures spent more time lying down than animals in the open pastures (P ≤ 0.01), while lambs in the open spent more than two hours longer each day standing (P < 0.0001). During the hottest part of the day, ewes in the open pasture were 0.4 °C hotter than ewes in the black walnut silvopastures (P ≤ 0.0202). Lambs in the black walnut silvopastures grazed more (488 ± 14 minutes · day⁻¹ ) than lambs in the honeylocust silvopastures (438 ± 15 minutes · day⁻¹ ; P = 0.0192) and the open pastures (417 ± 14 minutes · day⁻¹ ; P = 0.0009), with no difference between the latter two systems (P = 0.3073). There was no difference in daily bites taken (P ≥ 0.7222), though lambs in the silvopastures grazed more frequently than lambs in the open pastures. In one six week winter grazing study, animal performance in the honeylocust silvopastures was compared with the productivity of lambs grazing the open pastures and the black walnut silvopastures. The objective of this study was to determine the effect of these pods on lamb growth when animals grazed stockpiled tall fescue (Schedonorus arundinaceus). Preand post-graze forage mass was estimated with a double sampling technique using a rising plate meter. Treatment pastures were rotationally stocked with three (walnut) or six lambs per experimental unit depending on forage availability. Fescue grab samples were collected every other rotation. Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and total digestible nutrients (TDN) were estimated with a robust equation using NIR spectroscopy. Pre- and post-graze pod mass per hectare was estimated using randomly placed quadrats. Lambs were naïve to pods and did not readily consume the fodder until four weeks into the trial, and the methods for estimating pod intake were not sufficient to detect pod differences in pre- and post-graze pod mass. Forage availability in the honeylocust silvopastures (5130 ± 90 kg · ha⁻¹ ) and open pastures (5050 ± 90 kg · ha⁻¹ ; P=0.7580) was greater (P < 0.0001) than forage availability in the black walnut silvopastures (3790 ± 90 kg · ha⁻¹ ). Treatment had no effect (P = 0.3763) on average daily gains across the six weeks of the study. However, lambs within the honeylocust silvopastures had greater (P = 0.0251) average daily gains in the final period (0.12 ± 0.02 kg · day⁻¹ ) than lambs within the open pastures (0 ± 0.02 kg · day⁻¹ ), and lambs were observed consuming the pods. These data suggest that honeylocust pods may support greater gains of lambs, but that previous exposure and longer study periods in pasture settings may be necessary to see their nutritional benefit when grazing high quality forages. / Ph. D.

Three tree species, Freeman maple (Acer x. freemanii), swamp white oak (Quercus bicolor (Willd.)) and shingle oak (Quercus imbricaria (Michx.)) were tested before and after pruning to determine the effectiveness of pruning on reducing drag and bending moment. Pruning methods were thin, reduce and raise and meet the requirements set by the American National Standard Institute A300 standards for Tree Care Operations Trees, Shrub, and Other Woody Plant Maintenance - Standard Practices (Pruning). Trees were tested up to speeds of 22.4m*s-1 over 1.6km by driving them in the bed of a truck. Drag, based on a centroid of the crown, and a bending moment was calculated. Drag and bending moment were also normalized by tree mass and crown area. Reduction pruning worked more effectively for Freeman maple and raise pruning for swamp white oak at reducing drag. Simple to measure tree characteristics were analyzed to determine the best predictors of drag and bending moment in the field. Tree mass frequently was the best predictor of drag and bending moment. Information should be used with caution due to the fact that the trees tested were small stature and a limited number of trees were tested. / Master of Science

Greenhouse and field studies were conducted to determine the effects of shade on photosynthetic, growth and yield responses of "Redchief" strawberries. Plants were exposed to 0 , 30 , 47 and 63 percent shade in the greenhouse. Net photosynthesis (Pn) as measured under the shade treatments demonstrated a curvilinear decrease. Pn as measured under saturating light levels of 790 μ-tmol· m-2 · s·1 began to decrease in plants grown under 30 percent or higher shade levels. Light saturation curves for leaves expanded in full sun and then transferred to shade treatments for seven days showed a decrease in Pn saturation rate and light saturation point at 63 percent shade. Saturation curves for leaves expanded under the shade treatments exhibited a decreasing trend in saturation rate and point at all shade levels. Heavy shade (63%) reduced leaf thickness and depth of the palisade cell layers. Individual leaf area was not affected by shade treatments. As percent shade increased, total plant dry weight decreased linearly as did specific leaf weight. Shade treatments of 0, 30, 63 or 95 percent were applied over field-grown plants either in the fall during flower bud initiation, or in the fall and spring, during flower bud initiation and spring vegetative growth. Berry number was reduced as percent shade increased. Plants shaded only in the fall had higher berry number than plants shaded both in the fall and spring. Berry weight was also reduced as percent shade increased. Sugar concentration, pH and titratable acidity were not affected by shade levels or time of shade application. / Master of Science

This study determined winter and summer shading coefficients for six commonly used landscape trees in Tucson using a photographic dot-matrix method. Tree types were developed from this data reflecting canopy density, shape, and foliage periods, then applied to SPS and MICROPAS computer programs to model effects of tree shade on annual energy loads for three residential construction types. Statistical analysis showed pruning to have a significant effect for 5 of the 6 species tested. Significant differences were also found among species and within species due to seasonal effects in foliage density. Shading scenarios manipulated the number and location of tree types were modeled. Greatest net annual savings were from 3 African sumac trees located on the west side of a masonry house typical of the 1950s (121). Shade from tree species found to have significantly different shading coefficients (10%) did not substantially increase energy savings ($5-12).

Thesis advisor: Janet E. Helms / Black women are often confronted with social-systemic barriers and differential treatment based on the shade of their skin color. Colorism, a derivative of racism, is the use of skin-color shade as the basis for interactions with and evaluations of Black women. Some theoretical and empirical literature suggests that Black women may encounter and respond to colorism in various social contexts. Nevertheless, without an adequate measure to assess these contextually based experiences, it is difficult to explore the complex dynamics of the colorism that Black women face. In the present study, socioecological theory (Brenner, Zimmerman, Bauermeister, & Caldwell, 2013) was adapted to frame a contextual model of colorism in order to develop a measure that assesses Black women’s perceptions of and responses to colorism across social contexts, including in their families, within and outside of their racial community, and in society. Black women (N = 299) responded to 98 contextual items derived from personal accounts of colorism, focus groups, and theoretical literature. Various scale development techniques including item analysis, exploratory factor analyses, and parallel analyses yielded four dimensions of perceived colorism experiences (i.e., racial out-group, family, racial in-group, society) and seven dimensions of perceived colorism responses (i.e., racial out-group/society, family and racial in-group cognitive-emotional reactions, family and non-family positive colorism, negative self-concept, attractiveness). To investigate validity evidence, multivariate multiple regression analyses (MMRAs) and hierarchical multiple regression analyses were conducted to examine relationships between the factor-derived subscales of the Perceived Colorism Scale and internalized colorism, racial identity, and self-esteem. Overall, results of the analyses supported the importance of four contexts for colorism experiences (racial out-group, family, racial in-group, and society). However, context-related responses to colorism were more complex than initially hypothesized. The factor-derived PCS subscales were predictive of internalized colorism, racial identity and self-esteem. Nonetheless, the subscales varied in the extent to which they were related to the validity measures and some of the significant relationships were not in hypothesized directions. Methodological limitations, along with implications for future theory, research, and practice are discussed. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental and Educational Psychology.