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Full-Text Articles in Physical Sciences and Mathematics

Sun Exposure And Protective Behaviors Among U.S. Hispanic Farmworkers, Claudia Marie Delgado Cebollero Jan 2023

Sun Exposure And Protective Behaviors Among U.S. Hispanic Farmworkers, Claudia Marie Delgado Cebollero

Walden Dissertations and Doctoral Studies

Sun exposure increases the risk of sun-related illnesses and skin cancer among U.S. Hispanic farmworkers. Reinforced by the health belief model, the purpose of this study was to determine the association between socio-demographic factors (i.e., age, educational attainment, gender, income, and marital status) and skin cancer with the level of sun exposure (sun’s effect on skin, sunburn reported) and protective behaviors (use of cap/visor, use of sunscreen) among adult Hispanic farmworkers in the United States. The study included Hispanic farmworkers aged 21 or older (N = 112) who responded to the 2015 National Health Interview Survey. Ordinal logistic regression showed …


Crop Modeling For Assessing And Mitigating The Impacts Of Extreme Climatic Events On The Us Agriculture System, Zhenong Jin Apr 2016

Crop Modeling For Assessing And Mitigating The Impacts Of Extreme Climatic Events On The Us Agriculture System, Zhenong Jin

Open Access Dissertations

The US agriculture system is the world’s largest producer of maize and soybean, and typically supplies more than one-third of their global trading. Nearly 90% of the US maize and soybean production is rainfed, thus is susceptible to climate change stressors such as heat waves and droughts. Process-based crop and cropping system models are important tools for climate change impact assessments and risk management. As data- science is becoming a new frontier for agriculture growth, the incoming decade calls for operational platforms that use hyper-local growth monitoring, high-resolution real-time weather and satellite data assimilation and cropping system modeling to help …


Anaerobic Digester Use In Dairy Farms In The United States, Shaun Elsasser May 2006

Anaerobic Digester Use In Dairy Farms In The United States, Shaun Elsasser

UNLV Theses, Dissertations, Professional Papers, and Capstones

Anaerobic digestion is a highly efficient process, trapping the methane gas from cow manure and processing it into energy. The steep initial capital costs make anaerobic digesters short-term liabilities, but the long-term benefits far outweigh the long-term costs. An anaerobic digester unit will begin to show a profit after approximately five years of operation. During the lifetime of the unit, estimated at 15 years, the digester will have produced about $ 1,000,000 in profits for the dairy farm, while also providing invaluable benefits to society as a whole.


Modeling Plankton Community Structure Under Environmental Forcing On The Southeastern United States Continental Shelf, Andrew Glenn Edward Haskell Jan 1997

Modeling Plankton Community Structure Under Environmental Forcing On The Southeastern United States Continental Shelf, Andrew Glenn Edward Haskell

OES Theses and Dissertations

A system of coupled ordinary differential equations was developed to investigate the time-dependent behavior of phytoplankton, copepod, and doliolid populations associated with upwelling features on the outer southeastern U.S. continental shelf. Model equations describe the interactions of nitrate, ammonium, two phytoplankton size fractions, five copepod developmental stages, doliolids, and a detrital pool. Model dynamics are based primarily upon data obtained from field and laboratory experiments made for southeastern U.S. continental shelf plankton populations. Numerous simulations were performed to investigate the effects of environmental variability on the temporal distribution of the structure of resident plankton populations. Variations on a reference simulation, …