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Desarrollo social de menores a través del deporte en la reglamentación del Departamento de Recreación y Deportes de Puerto Rico
(2023-12-15)
This research consists of examining the guidelines of the theories of positive social development and sport for development in the laws and regulations active in August 2023 applicable to the minor categories of Puerto ...
Los teleproyectos en las redes virtuales de aprendizaje, las gestiones de apoyo a la docencia y el desarrollo de competencias de comunicación para el siglo XXI
(2023-12-07)
La integración de la tecnología en la educación ha transformado la enseñanza tradicional, allanando el camino a estrategias pedagógicas innovadoras que atienden mejor las diversas necesidades del estudiantado del siglo ...
La ergonomía organizacional y la salud ocupacional de los empleados
(2023-12-14)
El estudio realizado pretendió explorar cómo las prácticas de ergonómica organizacional inciden en la salud ocupacional de los empleados. El objetivo principal consistió en abordar los principales factores ergonómicos que ...
El empleador único y la movilidad como elemento de transacción de recursos humanos en el sector público puertorriqueño
(2023-12-11)
Esta investigación estudia la Ley para la Administración y Transformación de los
Recursos Humanos en el Gobierno de Puerto Rico”, Ley Núm. 8 del 4 de febrero de 2017,
resaltando el empleador único y la movilidad como ...
Retos del modelo de consolidación de agencias: El caso del Departamento de Seguridad Pública
(2023-12-15)
En Puerto Rico se ha intentado de diferentes maneras atender el tema de la seguridad y
protección pública. La consolidación de servicios parece ser la solución a muchos de los
problemas que son atendidos por diferentes ...
A comprehensive study of beachrock in Puerto Rico: morphology, texture, cementation and its implications in coastal processes, including coastal erosion.
(2023-06-01)
Beachrocks in Puerto Rico are millennial-scale geologic features formed in coastlines by cementation of heterogeneous coastal sediments (sand and/or gravel). The factors and mechanisms of beachrock formation and its ...
A socioecological approach using watershed health and social vulnerability in a headwater sub-basin of the Río Grande de Arecibo
(2023-05-25)
The Río Grande de Arecibo (RGA) Watershed is a crucial source of water through the North Coast Super Aqueduct for the residents of the Island of Puerto Rico, including those living in the San Juan metropolitan area. It is ...
Titanium oxide nanoparticles in the freshwater ecosystem: Atya lanipes shrimp as a nanotoxicological model
(2023-05-16)
This dissertation specializes in studying and determining the environmental concentrations of an emerging pollutant of which we do not fully know, titanium oxide nanoparticles (TiO<sub>2</sub> NPs). Although we are aware of the extensive use and commercial production of this nanoparticle in the US and that there are various sources of contamination and their entry into rivers, we are almost completely unaware of the environmental concentrations that exist in Puerto Rico. There is little knowledge of the toxicological effects that could be associated with ecologically susceptible species. To date, there are no federal or state regulations for acceptable environmental concentrations in our rivers. This study aims to determine the actual status of urban and rural rivers in Puerto Rico related to the presence/absence of TiO<sub>2</sub> NPs and the specific fate and behavior in a laboratory-controlled environment. Also, we want to understand and measure how the presence of these nanoparticles in the freshwater ecosystem results in lethal and sublethal effects due to the toxicity of the TiO<sub>2</sub> NPs, on the life cycle of an endemic shrimp in Puerto Rico, Atya lanipes. The objectives of this dissertation are: 1) Determine the environmental concentrations of titanium oxide nanoparticles and the fate and behavior laboratory assessment, 2) Describe the early larval development description of the freshwater shrimp Atya lanipes Holthuis, 1963 (Decapoda: Caridea: Atyidae), 3) Establish titanium oxide nanoparticles as emerging aquatic pollutants evaluating the nanotoxicity in the freshwater shrimp larvae Atya lanipes, and 4) Determine the neurotoxicity and oxidative stress development in adult Atya lanipes shrimp exposed to titanium oxide nanoparticles. Through field and laboratory studies, we obtained for the first time the concentrations of titanium oxide nanoparticles in sediment and dissolved titanium in water from the Rio Piedras and Sabana rivers. Also, we were able to elucidate the first nine (9) larval stages of the Atya lanipes shrimp. Then, after acute and chronic exposures, we evaluated lethal and sublethal toxic effects in both larval and adult stages of the Atya lanipes shrimp. This study is an innovative one that contributes significantly to our scientific knowledge of the magnitude of the concentration of TiO<sub>2</sub> NP that we are facing. It provides a starting point to begin public policy and better management in the use and discharge of this type of nanomaterial....
Analysis of population size and food preference of Pterygoplichthys multiradiatus: focus on microplastics in streams with different human impacts
(2023-05-31)
The pollution and accumulation of plastic in the environment, along with its mass production, has grown significantly in recent decades. Plastic can be very persistent due to its durability, and strength. Furthermore, they can disperse to any habitat under the influence of wind, rain, and runoff. In addition, as a direct result of the widespread use of plastics in modern society, plastic waste accumulates, especially in urbanized areas where it often ends up in watercourses and is eventually transported to river bodies. Pollution from fluvial plastic transport, particularly from rivers, remains relatively understudied compared to marine plastic litter. However, recent research efforts to quantify plastic pollution and its effects have begun to focus on freshwater systems because rivers ultimately discharge their waters into the ocean. However, given that research on riverine plastic debris transport is a relatively young science, the need to emphasize the urgency of increasing global knowledge about plastic pollution in freshwater ecosystems is necessarily important.<br />
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Most rivers with high concentrations of plastic debris are located near urban areas, presenting significant risks to aquatic life and biodiversity. Because of this, urban river segments are particularly susceptible to invasion by exotic species, which is common in locations with poor water quality. Introducing exotic species into urban water bodies is a common problem in many cities worldwide. Exotic fish can displace native species, disrupt the ecological balance and contribute to the spread of diseases and parasites. This can be problematic as some exotic fish, such as species in the families Poeciliidae, Cichlidae, and Loricariidae, can be particularly prolific and can expand rapidly, which can further increase their negative impact on the local ecosystem. Pterygoplichthys is a genus of freshwater fish family Loricariidae, commonly known as plecos or armored catfish. These fish are native to Central and South America and are found in rivers and lakes in the region. However, some members of the genus Pterygoplichthys have become invasive species in some parts of the world. Such is the case with Pterygoplichthys multiradiatus, a freshwater fish species popular with aquarists because it controls algal growth in aquariums. It is believed that Pterygoplichthys multiradiatus may compete with other native fish species for resources and habitats and alter algal communities and other aquatic organisms. Similarly, in Puerto Rico, government agencies, such as the Department of Natural and Environmental Resources, have classified plecos as an invasive species, which has caused severe damage to economic sectors such as agriculture and fisheries, as well as adverse effects on the island's biodiversity that represent a threat to the public health of the surrounding communities.<br />
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Pterygoplichthys multiradiatus has detritivorous habits and demersal distribution adapted to attach to the substrate to consume algae, organic sediments, and small invertebrates in river bodies. This may increase the risk of plastic ingestion for bottom-dwelling species as they decompose into smaller fragments that are easier to consume and have a higher probability of carrying contaminants. Therefore, given the accumulation of anthropogenic waste reaching rivers, this has resulted in an increasing generation of plastic debris in a variety of sizes to which aquatic biological organisms are exposed. However, as large plastic waste is broken down into small particles by photodegradation and biodegradation, these plastic fragments, form microplastics.<br />
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However, because populated islands are also potential sources of plastics, the Caribbean islands are a vulnerable point in the degradation of biodiversity resources, including terrestrial and aquatic ecosystems. In Puerto Rico, for example, which along with other islands is part of the Greater Antilles archipelago in the Caribbean region, there is little assessment of plastic contaminants in aquatic ecosystems. Therefore, the present study highlighted the contamination by plastic waste, particularly by microplastics, which were found in the gastrointestinal tract of freshwater fish Pterygoplichthys multiradiatus; being an exotic and invasive species able to tolerate disturbed ecosystems and with a wide distribution in urban streams of Puerto Rico. Because of this, the objectives of this study were: 1) to estimate the population size of Pterygoplichthys multiradiatus and to identify variations in the abundance of the species between urban and suburban streams, in relation to various land use scenarios; 2) to use the P. multiradiatus as a model organism, to determine, quantify and identify the types of microplastics found inside the gastrointestinal tract of the organism; finally, 3) to quantify the degree to which direct exposure to plastic affects the amount ingested by the plecos, in order to know and determine if the impact produced by these residues is a component of the main diet of the species....
American and Puerto Rican sign languages and issues regarding the need for interpreters for the deaf community in Puerto Rico
(2023-08-02)
The origin of language has been debated by many scholars. Among those who believe the use of gestures was critical is Gordon Hewes, an anthropologist at the University of Colorado. Hewes (1973, p. 8) states: “The beginnings ...