531 research outputs found
The Metastatic Receptor Status Impact on First-Line Treatment Plans and Outcomes for Recurrent Metastatic Breast Cancer
Background: For more than two decades, breast cancer researchers have studied the benefits, risks and clinical importance of testing the receptor status of metastatic tumors. While there is a growing consensus that the status should be re-tested and under what circumstances that re-testing should occur, there is little to no evidence that utilizing test results for metastatic tumor receptor status improves the clinical outcomes of patients. In fact, there is evidence that changes to treatment plans based on this re-testing can be harmful to patient outcomes.
Objective: This dissertation evaluates the current state of evidence related to altering patient treatment plans based on the re-test results of metastatic tumors, offers an update to existing national and international standards and executes a retrospective observational study to provide data that supports better informed decisions on first-line metastatic treatment plans where retesting of tumors is an option.
Methods: A thorough literature review was performed on the topic. Afterwards, a retrospective observational study was performed at the University of Tennessee Cancer Institute.
Conclusions: The research outcomes documented in this dissertation demonstrate that basing first-line treatment plans for metastatic breast cancer patients on the receptor status of the primary tumor instead of the metastatic tumor receptor status extends the life expectancy of patients. A standard of care is proposed that impacts national and international guidelines and reflects the risks associated with changing the first-line treatment plans of metastatic breast cancer patients based on the receptor status of metastatic tumors
Two's Company, Three's a Crowd: Experimental Evaluation of the Evolutionary Maintenance of Trioecy in Mercurialis annua (Euphorbiaceae)
Trioecy is an uncommon sexual system in which males, females, and hermaphrodites co-occur as three clearly different gender classes. The evolutionary stability of trioecy is unclear, but would depend on factors such as hermaphroditic sex allocation and rates of outcrossing vs. selfing. Here, trioecious populations of Mercurialis annua are described for the first time. We examined the frequencies of females, males and hermaphrodites across ten natural populations and evaluated the association between the frequency of females and plant densities. Previous studies have shown that selfing rates in this species are density-dependent and are reduced in the presence of males, which produce substantially more pollen than hermaphrodites. Accordingly, we examined the evolutionary stability of trioecy using an experiment in which we (a) indirectly manipulated selfing rates by altering plant densities and the frequency of males in a fully factorial manner across 20 experimental plots and (b) examined the effect of these manipulations on the frequency of the three sex phenotypes in the next generation of plants. In the parental generation, we measured the seed and pollen allocations of hermaphrodites and compared them with allocations by unisexual plants. In natural populations, females occurred at higher frequencies in denser patches, a finding consistent with our expectations. Under our experimental conditions, however, no combination of plant densities and male frequencies was associated with increased frequencies of females. Our results suggest that the factors that regulate female frequencies in trioecious populations of M. annua are independent of those regulating male frequencies (density), and that the stable co-existence of all three sex phenotypes within populations is unlikely
Sex-Differential Herbivory in Androdioecious Mercurialis annua
Males of plants with separate sexes are often more prone to attack by herbivores than females. A common explanation for this pattern is that individuals with a greater male function suffer more from herbivory because they grow more quickly, drawing more heavily on resources for growth that might otherwise be allocated to defence. Here, we test this ‘faster-sex’ hypothesis in a species in which males in fact grow more slowly than hermaphrodites, the wind-pollinated annual herb Mercurialis annua. We expected greater herbivory in the faster-growing hermaphrodites. In contrast, we found that males, the slower sex, were significantly more heavily eaten by snails than hermaphrodites. Our results thus reject the faster-sex hypothesis and point to the importance of a trade-off between defence and reproduction rather than growth
Using natural resource inventory data to improve the management of dryland salinity in the Great Southern, Western Australia
The synoptic assessment of salinity risk and the likely costs and benefits associated with various management options is crucial to natural resource management decision-making in southern Australia. A variety of methods have been proposed and tested for assessing various aspects of salinity risks and costs, but no large region of Australia has ever had a comprehensive risk assessment across the range of biophysical and economic issues with forecasts of the effectiveness of different levels of intervention. This National Land and Water Resources Audit Implementation Project (referred to locally as Salt Scenarios 2020, or SS2020 for short) attempted to provide such an assessment (at a scale of around 1:100,000).
The existing methods of monitoring and predicting salinity (based on variables derived from widely-available Landsat TM data and existing contour data; albeit with improved variable extraction from the DEMs) are being applied to the rest of the agricultural area of WA as part of the Land Monitor Project, funded in part by NHT. Collecting accurate contour data (2-metre) is a major part of the NHT project. This Audit project was proposed to allow other fundamental data sets, and especially groundwater levels from bore-hole data, to be used to significantly improve predictions in lower-rainfall areas as well as refine the predictions in the high rainfall areas.
The Great Southern is an area of considerable economic and environmental value populated by 60,000 people. In 1996, it was estimated that about 30% of the cleared land and associated vegetation and water resources are at risk from becoming salt-affected over the next 30 years unless high-water use farming systems and farm forestry are adopted over large parts of the region(Ferdowsian et al., 1996).
Four key questions arise with respect to the future of this region as affected by dryland salinity:
•How large will the problem eventually be under current land practices? How large might it be in the year 2020?
•What is at risk if the area under threat grows that large?
•To what degree can we change the eventual extent of salinity with land use alternatives that are both feasible and available?
•What are the costs and benefits of intervening with these alternative land uses?
Ultimately, the SS2020 Project aimed to provide some guidance to state, regional and local planners and managers regarding salinity risk in the Great Southern. The analyses underpinning this guidance were based on similar data employed by NLWRA projects under Theme 2 – Dryland Salinit
Probation staff experiences of managing suicidal and self-harming service users
The current study sought to explore the impact of suicidal behaviours on probation staff, in relation to their experiences of working with Probation service users who have carried out suicide, attempted suicide or self-harm. Thirteen in-depth interviews were carried out with probation staff who had direct contact with Probation service users in one Probation area, and had varying degrees of experience of managing suicidal or self-injurious service users. These were analysed using Thematic Analysis and five themes were identified. Findings indicate that staff felt that suicide and self-harm by service users are serious issues which need to be recognised and dealt with in an effective yet compassionate manner. However not attending the Suicide Prevention Training or lack of experience was perceived as restricting their ability to know how to deal with these individuals, and offer support. Furthermore, staff were emotionally affected by these incidents and it is recommend that they should continue to be provided with access to appropriate support services after an incident
Housing options for older people in a reimagined housing system: a case study from England
The housing options of older people now extend far beyond the traditional choice
between staying put and making do, or moving to specialist housing or residential care.
A flexible suite of options has emerged, centred on promoting independence and wellbeing.
Valuable insights have been provided into the development, delivery, costs and
benefits of these options. Light has also been cast on the experiences and preferences
of older people. However, little is know about who gets what housing, where and why.
This reflects a tendency within analysis to consider these different housing options in
isolation. This study responds by situating the housing options of older people within
wider debates about the reimagining of the housing system driven by the neoliberal
transformation in housing politics. Taking a case study approach, it explores the gap
between the ambitions of policy and realities of provision at the local level, relates this
to the particular intersection of state practices and market mechanisms manifest in the
case study and, in doing so, rises to the challenge of extending analysis of the impacts
of the neoliberal approach on the right to housing to new groups and different settings
Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides
This is the publisher’s final pdf. The published article is copyrighted by the Public Library of Science and can be found at: http://www.plosone.org/home.action.With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore, macroalgal competition decreased coral growth rates by an average of 36.8%. Overall, this study found that competition between corals and certain species of macroalgae leads to an altered coral microbiome, providing a potential mechanism by which macroalgae-coral interactions reduce coral health and lead to coral loss on impacted reefs
High genetic diversity at the extreme range edge: nucleotide variation at nuclear loci in Scots pine (Pinus sylvestris L.) in Scotland
Nucleotide polymorphism at 12 nuclear loci was studied in Scots pine populations across an environmental gradient in Scotland, to evaluate the impacts of demographic history and selection on genetic diversity. At eight loci, diversity patterns were compared between Scottish and continental European populations. At these loci, a similar level of diversity (θsil=~0.01) was found in Scottish vs mainland European populations, contrary to expectations for recent colonization, however, less rapid decay of linkage disequilibrium was observed in the former (ρ=0.0086±0.0009, ρ=0.0245±0.0022, respectively). Scottish populations also showed a deficit of rare nucleotide variants (multi-locus Tajima's D=0.316 vs D=−0.379) and differed significantly from mainland populations in allelic frequency and/or haplotype structure at several loci. Within Scotland, western populations showed slightly reduced nucleotide diversity (πtot=0.0068) compared with those from the south and east (0.0079 and 0.0083, respectively) and about three times higher recombination to diversity ratio (ρ/θ=0.71 vs 0.15 and 0.18, respectively). By comparison with results from coalescent simulations, the observed allelic frequency spectrum in the western populations was compatible with a relatively recent bottleneck (0.00175 × 4Ne generations) that reduced the population to about 2% of the present size. However, heterogeneity in the allelic frequency distribution among geographical regions in Scotland suggests that subsequent admixture of populations with different demographic histories may also have played a role
Risk Factors for Post-ERCP Pancreatitis: A Prospective Multicenter Study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75082/1/j.1572-0241.2006.00380.x.pd
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