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Pre-marital cohabitation has become a mainstream practice among couples in the United States, yet initial empirical evidence demonstrated significant correlations between cohabitation and subsequent marital instability. Later studies disputed a causal relation and have attempted to show a weakened connection over time, but have themselves suffered from the use of exclusively older and/or unreliable data. This paper uses figures from the National Longitudinal Survey of Youth (1997-08) and the National Survey of Family Growth (2006-08) to provide an updated analysis of cohabitation’s effect on marriage over the past decade. Using proportional hazard and competing risk models, this paper confirms a now minimal impact of cohabitation on marriage stability, with possible exceptions for serial cohabitation and cohabitation begun prior to engagement. Moreover, this study finds that cohabitation overwhelmingly remains a step toward, rather than serious substitute for, marriage.

IMPORTANCE: Advanced stage head and neck cancers are often deemed unresectable due to the aggressive nature of the cancer. In evaluating survival patterns of patients with stage IVb tumors, it is valuable to determine whether patients who undergo oncological surgery have favorable outcomes in order to deem surgery as a viable treatment option and demonstrate that these patients can survive with adequate treatment. OBJECTIVE: To determine whether patients with stage IVb cancers who undergo oncological surgery have favorable survival outcomes. MATERIALS AND METHODS: Of 320 cases reviewed of patients treated for head and neck cancer at Boston Medical Center between June 2009 and October 2014, 18 patients with stage IVb tumors were identified. Information regarding date of initial diagnosis, date and type of treatment, and date of death were extrapolated from medical records. Mean survival rates were calculated to compare survival outcomes of those who received and those who did not receive surgical intervention. RESULTS: The mean survival rate for patients who underwent surgical intervention was found to be 29.5 months while those who did not receive surgical intervention had a mean survival of 20.83 months. CONCLUSION: Cancers of the head and neck are associated with poor prognoses and are often deemed unresectable. Patients should be offered definitive treatment despite recommended palliative treatment, as, with adequate treatment, favorable survival outcomes are attainable.

American black duck (Anas rubripes) populations declined throughout North America from 1950–1990, but the breeding population since has stabilized. However, limited information exists on black ducks in the Mississippi Flyway, where wintering populations continue to decline. I radiomarked 111 female black ducks at Tennessee National Wildlife Refuge (TNWR) in winters 2010–2012 to estimate winter survival and investigate patterns of habitat selection. Winter survival (83–85%) was greater than or comparable to previous estimates for black duck populations in North America. Interval survival increased 0.6% with a 100 g increase in body mass, but survival differed between years and waterfowl hunting seasons relative to body mass. Black ducks selected habitats on TNWR and emergent/scrub-shrub wetlands throughout winter regardless of hunting season or time of day. High winter survival rates and consistent use of TNWR suggest the refuge provides an important complex of habitats for black ducks wintering in Tennessee.

The freshwater mussel fauna of the Clinch River in Southwest Virginia has declined in recent decades, principally due to habitat degradation from poor land-use patterns and pollutants. A study was undertaken to determine the feasibility of using river water in a flow-through culture system to rear juvenile freshwater mussels. The culture method placed juvenile mussels, confined in small dishes, into oval troughs supplied with untreated river water. Two of three years produced acceptable survival rates of 27% and 19% to an age of 90 days or greater. The third year yielded very low survival rates of less than 3%, demonstrating that failures in culture production can occur. Growth rates of juveniles in the culture system using river water were almost double those in laboratory culture systems, provided that juveniles were placed in the oval troughs during June. Otherwise, growth was comparable to that attained in laboratory culture systems. / Ph. D.

Microorganisms are known to tolerate a variety of extreme environments, such as high and low pH, desiccation and a wide range of temperatures that would prove uninhabitable for most eukaryotic cells. However, extreme radiation exposure is a ubiquitous hazard to pro- and eukaryotic viability. Ionising and non-ionising radiation, and their associated high energies, cause damage to a cell in the form of DNA double-strand breaks, membrane deterioration, and lethal mutations. Radiation also induces secondary effects such as the production of reactive oxygen species, which attack and degrade organic compounds. It is therefore not surprising that radiation is considered by the scientific community to be one of the main influencing factors when regarding habitability on the early Earth, as well as other planets, such as present-day Mars. This thesis explores the response of select microbes that have been exposed to extreme radiation environments, i.e. both high and ultra-low radiation. Understanding how radiation affects the geochemical environment is key to the assessment of its potential to support life and to harbour molecules associated with life. The effect of radiation-induced photochemistry on the early terrestrial and present-day Martian surface is explored in conjunction with Fenton chemistry. Iron oxides are abundant on both Earth and Mars and act as catalysts in Photo-Fenton reactions, enabling the production of free radicals. The resulting consequences for habitability are shown to be antagonistic, with iron oxide enabling both the protection or destruction of cells, depending on the local geochemistry. In addition, the photo-reactivity of perchlorate is investigated. The UV-induced activation of the strong oxidant, and recently confirmed Martian surface constituent, is demonstrated, revealing its severe bacteriocidal effect on microbes. It is also shown to significantly reduce microbial viability when combined with further Martian soil constituents and components required for Photo-Fenton chemistry. In order to accurately analyse the effects of low earth orbit radiation on prokaryotic life, cyanobacterial samples were attached to the outside of the International Space Station as part of the EXPOSE-R2 mission for 1.5 years. The samples were subjected to various conditions, including exposure to a minimally filtered space radiation environment and simulated Mars conditions. The experiment is designed to test the protection that biogenic and non-biogenic substances may provide to cells. The results in this work present the post-flight analysis of the samples and demonstrate the ability of these substances to maintain cyanobacteria viability. They also show that the cyanobacterial cells themselves can effectively act as a shield for a secondary, co-cultured bacteria species. On the other end of the radiation dose scale, this work addresses the gaps in knowledge with regard to the little-understood effects of low, sub-background radiation on prokaryotes. Using the Boulby Underground Lab in the functioning Boulby Mine, Cleveland UK, microbes are cultivated under regulated, extremely low radiation environments to test multiple dose-response models. The results show no change in cell's growth rates or gradients in low radiation exposure when compared to surface-dose controls. They also fail to exhibit any enhanced susceptibility to stress factors, such as UV irradiation, as suggested by previous work in the field. These experiments mark the first extensive and tightly controlled research into microbial responses in the near-absence of radiation. This work illustrates the importance of understanding both primary and secondary effects of radiation on microbes and begins to bridge the knowledge gap from both ends of the dose axis. These approaches show the far-reaching influence radiation has on astrobiologically relevant topics, such as habitat geochemistry and life detection, and demonstrate the capacity of life to survive in extreme radiation environments.

As compared to pediatric and older adult cancer patients, young adults are the only oncology group that has not demonstrated an increase in survival rates. Low treatment adherence rates have been one explanation for this discrepancy, although this hypothesis has not been explored specifically. Guided by the biopsychosocial model of health and wellness, this study compared the treatment adherence rates of 46 young adult cancer patients (ages 18-39 years) to 46 older adult cancer patients (ages 40 years and older). Adherence was measured by a dichotomized variable, as yes/no, adhering to radiation treatment and follow-up appointments recommended by the physician, 95% of the time. Additionally, gender and race were explored in relationship to adherence to radiation treatment and follow-up appointments. Demographic data were first extracted from the Cancer Registry of a Midwestern Hospital. Then radiation appointments and follow-up appointments were examined for each patient, in paper and/or computerized charts, to determine adherence rates. McNemar's test was used to compare young adults and older adult oncology patients' adherence rates, and Chi-square analysis was used to explore gender and race in relationship to adherence. Results indicated a lower adherence rate to follow-up appointments for younger adults as compared to older adults, with older adults adhering 3 -½ times more than younger adults. Gender was also related to follow-up appointment adherence, with males adhering better than females. This study contributes to positive social change by increasing the knowledge base of healthcare providers on adherence rates of young adult patients and reducing the dollars spent on treatment for re occurrences.

The study was conducted to examine the effect of exploitation on population parameters of coyotes (Canis latrans). Hypotheses tested were: (1) Substantial levels of exploitation do not change spring and fall coyote densities significantly; (2) Coyote recruitment (reproduction and immigration) rates are unaffected by substantial levels of exploitation; (3) Annual coyote survival rates are not related to intensity of harvest rates; (4) Coyote emigration rates remain unchanged by substantial levels of exploitation. Coyote demographic parameters were measured from 1975 to 1978 for a treatment population subject to substantial exploitation (Curlew Valley, Utah and Idaho), and for an unexploited to lightly exploited control population (Idaho National Engineering Laboratory, INEL). Treatment and control populations were about 100 km apart on environmentally similar areas. Availability and utilization of prey also were similar for the two populations, with the major difference being in the type of lagomorph consumed. Relative spring densities, estimated by scent station indices, increased for both populations over the study period. Relative fall densities in the two areas were estimated by scent station lines, scat indices, and catch-effort indices and increased from 1975 to 1976, but were relatively constant thereafter. Estimates of absolute fall density from isotope labeling of feces also were similar within each area for 1977 and 1978. Neither spring nor fall density estimates were significantly different between areas in any given year or overall. Recruitment rates, as estimated from spring to fall increase in scent station visitation rates generally decreased over the study period, while estimates from age and sex structure of coyotes trapped in the fall increased for both populations over the study period. Estimated recruitment to fall populations (Pf) was consistently greater in Curlew Valley each of the four years, and overall was significantly greater than recruitment at the INEL. Spring to fall change in scent station indices was greater for Curlew Valley for all years except 1975. Annual survival rates were estimated for adults and juveniles marked with transmitters and/or ear tags using methods of statistical inference from band recovery data. Estimated survival rates for adults and juveniles were constant over the study period for each population and did not differ significantly between populations. Estimates of adult and juvenile survival and/or recovery (mortality) rates were significantly different within the Curlew Valley and INEL populations. Estimated hunting mortality rates for adults and juveniles remaining in the treatment population were 56 and 350 percent higher than similar estimates for the control population. Significantly higher in situ juvenile hunting mortality rates were associated with significantly lower nonhunting mortality and emigration rates. Emigration was not only greater from the control population, but it was distributed more evenly over the fall and winter. The following conclusions resulted from the study. Exploitation (kill) rates were substantially higher in the treatment population as expected. Observed differences in fall-winter adult and juvenile in situ kill rates did not produce significant differences in spring or fall densities, or in annual survival rates. Recruitment rates were related directly to hunting mortality rates, while emigration rates were related inversely.

A demanda por projetos de restauração ecológica, com a utilização de técnicas de plantio total, tem aumentado nos últimos anos, com a consequente necessidade de otimização dos insumos para tal atividade que, além de garantir maior sobrevivência das mudas a campo, é essencial para o setor. Assim, as compensações ambientais, geradas pela obra do trecho sul do Rodoanel Mário Covas (São Paulo), proporcionaram uma importante oportunidade de se realizar alguns estudos nessa temática. O objetivo deste trabalho foi avaliar a taxa de sobrevivência e o crescimento inicial (12 meses), de 30 espécies arbóreas nativas, provenientes de mudas acondicionadas em recipientes com 3 volumes distintos (tubetão 290 cm3, tubetinho 56 cm3 e bandeja 9 cm3), com e sem utilização de hidrogel no plantio, e submetidas às mesmas ações de manutenção. As espécies nativas regionais contemplaram todos os grupos sucessionais (pioneira e não pioneiras), pertencentes a 17 famílias botânicas. Como resultados deste trabalho, pode-se concluir que as espécies provenientes do recipiente tubetão obtiveram as menores porcentagens de mortalidade, seguidas de tubetinho e bandeja, entretanto algumas espécies de bandeja mostraram-se com índices de mortalidade menores, se comparadas a outras espécies provenientes de tubetinhos, apresentando assim possibilidades de uso, desde que adotados manejos diferenciados (irrigação pós-plantio e controle de competidores) visando a garantir o aumento da sobrevivência inicial das mudas. O hidrogel não interferiu no estabelecimento e nem no crescimento das mudas nos diferentes recipientes, para o período em que o experimento foi avaliado. Quanto ao desenvolvimento das mudas em crescimento e incremento de altura, pode-se concluir que, uma vez garantido o estabelecimento das mudas, não houve diferenças entre os recipientes, reforçando que, com manejos diferenciados, os custos da restauração poderão ser significativamente reduzidos, para as situações que exijam como metodologia o plantio total na restauração ecológica de uma dada área. / The demand for ecological restorations project, using total planting techniques, has increased in recent years, with the consequent optimizations need of inputs for such activity that, besides increasing the seedlings survival in the field, is essential for the sector. Thus, environmental compensation, generated by the work of the southern section of the Rodoanel Mário Covas (São. Paulo), provided a valuable opportunity to conduct some studies in this area. This studys aim was to evaluate the survival rate and early growth (12 months) of 30 native species from plants in containers packed with three separate volumes (290 cm3 tubetão, tubetinho 56 cm3 and bandeja 9 cm3), with and without hydrogels use at planting, and subordinated to the same maintenance actions. The regional native species, contemplated at all successional groups (pioneer and non-pioneer), belonging to 17 botany families. As a result of this work, we can conclude that species from the container tubetão had the lowest percentage of mortality, followed by tubetinho and bandeja, however some bandeja species have come out with lower mortality rates, compared to other species from tubetinhos, thus presenting use opportunities since different management are adopted (irrigation after planting and control of competitors) in order to guarantee the increase of initial survival of seedlings. The hydrogel did not affect the establishment and neither the growth of seedlings in different containers, during the period in which the experiment was evaluated. Concerning the seedlings development in growth and increase in height, one can conclude that once guaranteed the seedlings establishment of, there were no differences between the containers, reinforcing that with different managements, the restoration costs may be significantly reduced for situations that require the total planting as a methodology in ecological restoration of a given area.