California State University (CSU): Open Journal Systems
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Investigations in Patterns in Last Digits of Square Numbers and Higher Powers
Get PDFIt is interesting to see what patterns exist in the final digits of powers of integers; the goal of this work is to introduce some new problems and results, which are ideally suited for interested readers to pursue further. We start our investigation with squares and say a square is a k-square good number if its last k digits base 10 are the same non-zero number, and the last k + 1 digits are not identical. We completely analyze k-square good numbers; when k = 1 we can have final digits of 1, 4, 5, 6 and 9 (with the second to last digit different), when k = 2 we can end with 44 but not 444, when k = 3 we can end with 444 but not 4444, and there are no 4-square good numbers. We then generalize these arguments to look at k-cube and k-fourth good numbers, completely analyzing these cases. Noting that any even power 2m is the same as squaring an mth power, we can extend our results to even powers more easily than to odd, as the behavior has to be a subset of what we have seen for squares. There are complications arising from powers of 2 dividing our numbers, but using results from elementary number theory (in particular concerning the totient function and Euler’s theorem), we reduce the problem for even powers to a tractable finite computation, and completely resolve this case, and then end with a list of accessible next problems
Changes in microbial enzyme activity in response to long- term dry season nitrogen inputs in semi-arid shrublands
Get PDFAtmospheric nitrogen (N) deposition has the capacity to alter soil microbial activity and organic matter decomposition. β-glucosidase, N-acetylglucosaminidase (NAGase), phosphatase, and peroxidase activity was measured in soils exposed to experimental N inputs for 13 years. We hypothesized that soils exposed to high N would have lower extracellular enzyme activity. Surface (0-10 cm) soil was sampled from the Sky Oaks Field Station and Santa Margarita Ecological Reserve in the spring of 2003, 2005, 2007, 2009, 2011, 2013, and 2015. The experimental design consisted of eight-10 x 10 m plots arranged in a paired-design. N plots have been fertilized annually since 2003 with 50 kgN/ha of dry N fertilizer, which is applied during the summer and fall of each year. β-glucosidase and phosphatase activity declined over time in added N plots at SOFS but not SMER, while peroxidase (Fig. 5) activity increased in added N plots at SOFS but not SMER. NAGase activity was not affected by N addition at either site. We found that added N stimulated peroxidase activity but inhibited b-glucosidase and phosphatase activity over time for SOFS, which is contrary to other experiments in deciduous forest. Decomposition and enzyme activity are affected by organic matter quality. Decomposition of more recalcitrant organic matter (SOFS) may be inhibited by N while more labile litter (SMER) may not be affected by added N
A Review of the Physiological Mechanisms Used to Combat Limited Water Availability in Reptiles, Mammals, Birds and Beetles Living in a Desert Environment
Get PDFDesert environments can be particularly harsh and unforgiving to their inhabitants which make it an ideal setting to study mechanisms of osmoregulation in different organisms. In this paper, we will be examining four different types of organisms that live in deserts around the world, comparing and contrasting their methods of osmoregulation. The South African Springhare (Pedetes capensis) concentrates its urine and dries out its feces in order to conserve water while the Gila Monster (Heloderma suspectum) reabsorbs water from its bladder to rehydrate itself in times of drought. The Namib Desert Beetle (Onymacris unguicularis) collects atmospheric moisture and uses metabolic water to stay hydrated, whereas the Turkey Vulture (Cathartes aura) concentrates urine and eliminates excess nitrogen to avoid poisoning its blood. Each of these organisms has a unique method of survival, showcasing the different mechanisms desert animals adapt in order to survive these harsh dry environments
Maternidades emergentes en La hija única de Guadalupe Nettel
Get PDFThis essay suggests that Guadalupe Nettel’s latest novel, La hija única (2020), translated into English as Stillborn, challenges the stereotypical views Mexican society has on mothers and mothering practices. Through the literary analysis of three female characters, who approach mothering from different perspectives, we’ll have a better understanding of the social pressures and personal hardships mothers face. The two-fold objective is to give visibility to the pressures and complications of motherhood to stop idealizing it as the best thing that can happen to women and to stop criticizing those who reject it.Este ensayo propone que La hija única (2020), la novela más reciente de Nettel, cuestiona las formas estereotípicas de entender a la madre y sus prácticas maternales. Por medio del análisis de tres personajes femeninos, quienes se aproximan al ejercicio del cuidado maternal desde diferentes perspectivas, comprenderemos las vicisitudes a las que las madres están atadas. El objetivo es darle visibilidad a las presiones y complicaciones de la maternidad para, por un lado, dejar de idealizarla como lo mejor que le puede pasar a una mujer y, por otro, dejar de estigmatizar a las que la rechazan
Mujer negra y cultura afrocubana en Reyita, sencillamente (Testimonio de una cubana negra nonagenaria) de Daisy Rubiera Castillo: de la percepción a la inclusión en la formación de la nación cubana
Get PDFThis article aims to discover new images of the Cuban black woman as well as to determine the vision she has of the Afro-Cuban culture from a feminine perspective from the analysis of the work Reyita, sencillamente (Testimonio de una negra cubana nonagenaria) by Daisy Rubiera Castillo. In this work, Reyita\u27s testimony reveals the image of an active black woman committed at different levels of life to the future of the Cuban nation. Giving value to herself, she vindicates the importance of her culture of African origin in the cultural panorama of Cuba.Resumen: Este artículo tiene como objetivo descubrir nuevas imágenes de la mujer negra cubana, así como determinar la visión que esta tiene de la cultura afrocubana desde una perspectiva femenina a partir del análisis de la obra Reyita, sencillamente (Testimonio de una negra cubana nonagenaria) de Daisy Rubiera Castillo. En esta obra, el testimonio de Reyita revela la imagen de una mujer negra activa comprometida en diferentes niveles de la vida para el devenir de la nación cubana. Dándose valor a sí misma, reivindica la importancia de su cultura de origen africano en el panorama cultural de Cuba
