Sydney Davis - Academia.edu (original) (raw)

Papers by Sydney Davis

SPORA: A Journal of Biomathematics, 2020

The large, long-lived, epiphytic bromeliad Tillandsia utriculata is currently listed as state-end... more The large, long-lived, epiphytic bromeliad Tillandsia utriculata is currently listed as state-endangered in Florida due to significant population reduction from predation by an invasive weevil, Metamasius callizona. We have developed a novel demographic model of a population of T. utriculata in Myakka River State Park (MRSP) in Sarasota, Florida using a stage-structured matrix model. Analysis of the model revealed conditions for population viability over a variety of parameter scenarios. Model analysis showed that without weevil predation the minimum germination rate required for population viability is low (4–16%), and that given a viable population at structural equilibrium we would expect to find <1% of the population in flower or post-flowering each year and, at most, about 10% of rosettes with longest leaf length (LLL) > 15 cm in flower or post-flowering each year. Additionally, the model presented here provides a basis for further analyses which explore specific conserva...

Interdisciplinary Science Reviews, 2000

Abstract Drug delivery systems have an important role to play in the administration of drugs, vac... more Abstract Drug delivery systems have an important role to play in the administration of drugs, vaccines, and diagnostic agents. Systems based on biodegradable polymers can be especially advantageous for use as implants that provide a slow, steady release of a pharmacological agent. Materials include poly--hydroxy acids, polyanhydrides, and polyphosphazenes. The products of biotechnology in the form of peptides and proteins are challenging compounds that are difficult to deliver. Novel methods of delivery include polymeric microspheres and microcapsules. Polymers can be used to deliver antigens in order to obtain improved responses after injection. Nanoparticles based on polymeric materials can be employed to deliver drugs to specific target sites, especially via the bloodstream or lymphatic system. Natural polymers also have an important role in drug delivery, for example chitosan is of special interest for its ability to interact with mucosal surfaces and to provide a bioadhesive effect that will retain drugs at target sites.

Environmental Toxicology, 2013

The objective of this study was to assess whether subchronic exposure to benzo(a)pyrene (BaP) via... more The objective of this study was to assess whether subchronic exposure to benzo(a)pyrene (BaP) via oral ingestion alter endpoints of the reproductive system of mice. Hsd: ICR (CD1) 10-week-old males (n 5 8) were randomly assigned to the exposure group and control group. Mice were administered BaP for 30 and 60 days by daily gavage at doses of 1, 10, 50, and 100 mg/kg body weight per day. At the end of the experiments, mice were anesthetized and reproductive organs, including testes, seminal vesicles, prostate, and cauda epididymis, were removed and examined. Spermatozoa quality and DNA strand breaks were assessed-1 and 10 mg/kg/day of BaP for 30 and 60 days did not significantly induce altered morphology or weights of testes, prostate, seminal vesicle, and epididymis, and spermatozoa quality of mice; 100 mg/kg/day of BaP for 60 days decreased weights of testes, seminal vesicle, and cauda epididymis. BaP exposure also significantly decreased motility, normal head morphology, vitality, and concentration of mature spermatozoa. In addition, BaP exposure induced a significant increase in DNA strand breaks.

Canadian Journal of Native Education, 1986

EJ342977 - The Participation of Indian and Metis Parents in the School System.

SPORA: A Journal of Biomathematics, 2020

The large, long-lived, epiphytic bromeliad Tillandsia utriculata is currently listed as state-end... more The large, long-lived, epiphytic bromeliad Tillandsia utriculata is currently listed as state-endangered in Florida due to significant population reduction from predation by an invasive weevil, Metamasius callizona. We have developed a novel demographic model of a population of T. utriculata in Myakka River State Park (MRSP) in Sarasota, Florida using a stage-structured matrix model. Analysis of the model revealed conditions for population viability over a variety of parameter scenarios. Model analysis showed that without weevil predation the minimum germination rate required for population viability is low (4–16%), and that given a viable population at structural equilibrium we would expect to find <1% of the population in flower or post-flowering each year and, at most, about 10% of rosettes with longest leaf length (LLL) > 15 cm in flower or post-flowering each year. Additionally, the model presented here provides a basis for further analyses which explore specific conserva...

Interdisciplinary Science Reviews, 2000

Abstract Drug delivery systems have an important role to play in the administration of drugs, vac... more Abstract Drug delivery systems have an important role to play in the administration of drugs, vaccines, and diagnostic agents. Systems based on biodegradable polymers can be especially advantageous for use as implants that provide a slow, steady release of a pharmacological agent. Materials include poly--hydroxy acids, polyanhydrides, and polyphosphazenes. The products of biotechnology in the form of peptides and proteins are challenging compounds that are difficult to deliver. Novel methods of delivery include polymeric microspheres and microcapsules. Polymers can be used to deliver antigens in order to obtain improved responses after injection. Nanoparticles based on polymeric materials can be employed to deliver drugs to specific target sites, especially via the bloodstream or lymphatic system. Natural polymers also have an important role in drug delivery, for example chitosan is of special interest for its ability to interact with mucosal surfaces and to provide a bioadhesive effect that will retain drugs at target sites.

Environmental Toxicology, 2013

The objective of this study was to assess whether subchronic exposure to benzo(a)pyrene (BaP) via... more The objective of this study was to assess whether subchronic exposure to benzo(a)pyrene (BaP) via oral ingestion alter endpoints of the reproductive system of mice. Hsd: ICR (CD1) 10-week-old males (n 5 8) were randomly assigned to the exposure group and control group. Mice were administered BaP for 30 and 60 days by daily gavage at doses of 1, 10, 50, and 100 mg/kg body weight per day. At the end of the experiments, mice were anesthetized and reproductive organs, including testes, seminal vesicles, prostate, and cauda epididymis, were removed and examined. Spermatozoa quality and DNA strand breaks were assessed-1 and 10 mg/kg/day of BaP for 30 and 60 days did not significantly induce altered morphology or weights of testes, prostate, seminal vesicle, and epididymis, and spermatozoa quality of mice; 100 mg/kg/day of BaP for 60 days decreased weights of testes, seminal vesicle, and cauda epididymis. BaP exposure also significantly decreased motility, normal head morphology, vitality, and concentration of mature spermatozoa. In addition, BaP exposure induced a significant increase in DNA strand breaks.

Canadian Journal of Native Education, 1986

EJ342977 - The Participation of Indian and Metis Parents in the School System.