868 research outputs found
Responding to change : phenotypic plasticity and local adaptation, case studies using native and invasive Erodium species
Phenotypic plasticity is often postulated to play a role in plant invasions. This thesis explores the role of plasticity in plant invasions with particular emphasis on responses to water availability. The thesis employed two main approaches; the first was a meta-analysis of published literature. The second approach was the use of greenhouse experiments on populations of a congeneric native (Erodium crinitum) - invasive (E. cictuarium ) species pair using seed collected along a natural rainfall gradient. The meta-analysis found that phenotypic plasticity is generally greater in invasive compared to non-invasive species. However this higher plasticity did not always translate to a fitness advantage. In particular, the fitness was partially dependent on whether conditions changed from stressful to average or average to favourable conditions. There were three main greenhouse studies. The first study compared patterns in phenotypic plasticity between wet and dry populations of the native and invasive Erodium species in response to four levels of water availability, ranging from water only at wilting point through to water to saturation daily. Responses in thirty size, growth, leaf morphological, physiological and phenological and fitness traits were measured. Patterns of plasticity in the native and invasive Erodium species were also investigated with respect to responses to water dose applications. Halving the dose at which water was applied had a greater effect on the fitness proxies: seed number and total biomass, than did halving the total amount of water supplied. Consistent with the other greenhouse study, dry site populations of both species displayed higher average seed number across all treatments than did wet site populations. However, the wet site populations maintained superior total biomass. While higher phenotypic plasticity in key traits resulted in higher fitness for seed number, homeostasis in total biomass was associated with lower levels of phenotypic plasticity. The third greenhouse study investigated constraints on plasticity in key traits to water availability and competition. It was expected that constraints would be greater when multiple stresses were present. However, this hypothesis was rejected. Although several constraints to plasticity were detected, such constraints were as common when only one stress was present as when both stresses were imposed. The thesis discusses the findings of these studies in the context of our current knowledge on plant invasions and species adaptation to climate change. Differences between the findings of the meta-analysis in which invasive species were generally more plastic than co-occurring native species, and findings of the greenhouse study, in which little difference was detected between species are also discussed. The results suggest that when range is controlled for invasive species are not inherently more plastic. Both the meta-analysis and the greenhouses studies also suggest that the shorter residency time of invasive species increases the probability that many plastic responses will be maladaptive. Indeed, the greenhouse studies found that species tended to respond more adaptively to situations which were more relevant to their ecological context. For example, dry site populations displayed greater adaptive plasticity than did wet site populations with respect to changes in water availability
Something for the girls : Demeter, Persephone, and Hecate in Eudora Welty\u27s Delta wedding and The Optimist\u27s daughter
Eudora Welty\u27s novels of Southern women and ritual reveal her desire to convey a woman\u27s world and to imbue it with a prelapsarian power of feminine self-knowledge. To create this world, Welty draws upon the mythological signifiers of Demeter, Persephone, and Hecate. Utilizing natural imagery of food and flowers, Welty develops a fecund, spring-like landscape and explores the relationship between character, author, and myth. What begins in Delta Wedding as a search to reaffirm the existence of a world spirit concludes in The Optimist\u27s Daughter as a triumphant rebirth of the feminine spirit. Laurel McKelva Hand, unlike her predecessor Laura McRaven, is no longer confined by a patriarchal system of self-definition; she is able to move freely between the boundaries of time and place and assume control of her own destiny
Academic Libraries and Non-Academic Departments: A Survey and Case Studies on Liaising Outside the Box
Partnering with non-academic departments allows academic libraries to create new programming ideas and reach more students. According to the results of a national survey, academic librarians at institutions of all sizes are partnering with many different types of non-academic departments. These partnerships offer efficiencies through shared cost and staffing and offer additional benefits to all groups involved. This article identifies the non-academic departments that these libraries are partnering with, highlights potential events to raise awareness of services, and describes ways in which these partnerships help engage with students
Healthy Options: A Community-Based Program to Address Food Insecurity
The objectives of this study are to better understand the lived experience of food insecurity in our community and to examine the impact of a community-based program developed to increase access to local, healthy foods. Participants were given monthly vouchers to spend at local farmers’ markets and invited to engage in a variety of community activities. Using a community-based participatory research framework, mixed methods were employed. Survey results suggest that most respondents were satisfied with the program and many increased their fruit and vegetable consumption. However, over 40% of respondents reported a higher level of stress over having enough money to buy nutritious meals at the end of the program. Photovoice results suggest that the program fostered cross-cultural exchanges, and offered opportunities for social networking. Building upon the many positive outcomes of the program, community partners are committed to using this research to further develop policy-level solutions to food insecurity
The Developing Law Governing Employee and Employer Rights Relating to Use of Electronic Media Within and Outside the Workplace
Employees are using electronic media at an increasing rate to communicate with others both in and out of the workplace. While email, social networking sites, blogs, text messages, and online videos may seem to present new and complex challenges for employees and employers, the decisional law suggests that the key to understanding issues presented by electronic media use is to reason by analogy to more “traditional” means of communication. For example, an email string between two people or among a group may be viewed similarly to an in-person conversation; the former is just memorialized in writing. A comment posted on an employee’s Facebook page may be treated like a verbal comment made by an employee to friends and coworkers. The same fundamental questions come up in the cases involving traditional or electronic communications: What was communicated? Who communicated it? When was it communicated? To whom was it communicated
Beautiful institution
These images were captured at the former Lennox Castle Hospital which was called, when it opened in 1936, a Certified Institution for Mental Defectives. The hospital closed in 2002
Fruit and Vegetable Bucks: Adams County Grocery Store Snap Incentive Program
Veggie Bucks provides a 50% discount on all fresh fruits and vegetables sold through Kennie’s Market produce department at the point of sale for the 5 highest cost items. The incentive period ran January - April, 2017. Intended outcomes include an increase in the number of fresh fruits and vegetables purchased by SNAP recipients at Kennie’s Market locations in Biglerville and Gettysburg by 10% in January-April 2017 compared to baseline figures obtained in 2016, and to familiarize SNAP recipients with fresh fruits and vegetables and to provide information about the ACFMA markets’ Double Dollars program. SNAP recipients were invited to sign up for the program upon showing their ID and EBT card and were provided a Kennie\u27s Frequent Shopper card if they did not have one already
Essential structural requirements for specific recognition of HIV TAR RNA by peptide mimetics of Tat protein
The pharmacological disruption of the interaction between the HIV Tat protein and its cognate transactivation response RNA (TAR) would generate novel anti-viral drugs with a low susceptibility to drug resistance, but efforts to discover ligands with sufficient potency to warrant pharmaceutical development have been unsuccessful. We have previously described a family of structurally constrained β-hairpin peptides that potently inhibits viral growth in HIV-infected cells. The nuclear magnetic resonance (NMR) structure of an inhibitory complex revealed that the peptide makes intimate contacts with the 3-nt bulge and the upper helix of the RNA hairpin, but that a single residue contacts the apical loop where recruitment of the essential cellular co-factor cyclin T1 occurs. Attempting to extend the peptide to form more interactions with the RNA loop, we examined a library of longer peptides and achieved >6-fold improvement in affinity. The structure of TAR bound to one of the extended peptides reveals that the peptide slides down the major groove of the RNA, relative to our design, in order to maintain critical interactions with TAR. These conserved contacts involve three amino acid side chains and identify critical interaction points required for potent and specific binding to TAR RNA. They constitute a template of essential interactions required for inhibition of this RN
The caregiving perspective in heart failure: a population based study
Background: Heart failure (HF) is a frequent condition in the elderly and mortality is high. This study sought to describe the profile of those providing care in the community and their needs. Methods: The South Australian Health Omnibus is an annual, random, face-to-face, cross sectional survey conducted within the state. Having standardized data to the whole population, the study describes the subset of the population who identify that they actively cared for someone at the end of life with HF in the five years before survey administration
- …