Dry Down Tolerance of the Florida Apple Snail (Pomacea paludosa, Say): Effects of Age and Season

This Research Work Order includes three experiments to look at apple snail dry down survival as a function of age and season. Two of those experiments have been completed and the third one will likely run through February (depending on snail survival). The third experiment began on September 2 1, 1998. The detailed results of Experiment # 1 and #2 were reported in the update report of 10/15/98. The overall survival for Experiments #I and #2 are included herein for comparison with Experiment #3. (7 page document

Contamination in complex healthcare trials:the falls in care homes (FinCH) study experience

BACKGROUND: Trials are at risk of contamination bias which can occur when participants in the control group are inadvertently exposed to the intervention. This is a particular risk in rehabilitation studies where it is easy for trial interventions to be either intentionally or inadvertently adopted in control settings. The Falls in Care Homes (FinCH) trial is used in this paper as an example of a large randomised controlled trial of a complex intervention to explore the potential risks of contamination bias. We outline the FinCH trial design, present the potential risks from contamination bias, and the strategies used in the design of the trial to minimise or mitigate against this. The FinCH trial was a multi-centre randomised controlled trial, with embedded process evaluation, which evaluated whether systematic training in the use of the Guide to Action Tool for Care Homes reduced falls in care home residents. Data were collected from a number of sources to explore contamination in the FinCH trial. Where specific procedures were adopted to reduce risk of, or mitigate against, contamination, this was recorded. Data were collected from study e-mails, meetings with clinicians, research assistant and clinician network communications, and an embedded process evaluation in six intervention care homes. During the FinCH trial, there were six new falls prevention initiatives implemented outside the study which could have contaminated our intervention and findings. Methods used to minimise contamination were: cluster randomisation at the level of care home; engagement with the clinical community to highlight the risks of early adoption; establishing local collaborators in each site familiar with the local context; signing agreements with NHS falls specialists that they would maintain confidentiality regarding details of the intervention; opening additional research sites; and by raising awareness about the importance of contamination in research among participants. CONCLUSION: Complex rehabilitation trials are at risk of contamination bias. The potential for contamination bias in studies can be minimized by strengthening collaboration and dialogue with the clinical community. Researchers should recognise that clinicians may contaminate a study through lack of research expertise

Assessing the impact of the Lake Kissimmee restoration on apple snails

Seasonal fluctuations in rainfall occur naturally in Florida, historically producing correspondingly large intra-annual and inter-annual fluctuations in lake water levels. As a result, "normal" lake levels are elusive; the norm is for wide fluctuations, a pattern which earned them the descriptive title, "astatic", or unstable (Brenner et. al. 1990). Lake Kissimmee, in Osceola County, FL, had a mean average water level fluctuation of 1.4 meters, but over several years varied as much as 3.7 meters (Grocki 1975).The substrate and vegetative communities, in part, reflect the pattern of hydrologic fluctuations, their timing, duration, and frequency. Topographic variability in lake systems, coupled with their hydrologic patterns, yield a mosaic of shrubby, emergent and submerged plant habitats in the littoral zone of the lake. Fish and wildlife have adapted accordingly, and successfully forage and reproduce in these highly fluctuating systems. Installation and operation of water control structures over the past 40 to 50 years have dampened the degree of hydrologic fluctuations in many Florida lakes, resulting in long term stabilization oflake levels [Holcomb and Wegener 1971, Wegener et. al. 1974, Fox et. al. 1977, Moyer and Williams 1982, Florida Game and Fresh Water Fish Commission (GFC) 1995]. The mean annual flux on Lake Kissimmee was reduced from 1.4 meters to 0.9 meters (Wegener et al 1973). In addition, increased nutrient inputs to Florida's watersheds from agricultural and urban development have resulted in lake eutrophication (Wegener et. al. 1974, Moyer and Williams 1982). As nutrients increased and water levels stabilized, rooted aquatic macrophytes expanded and organic debris accumulated to form undesirable lake substrates. Fish populations suffer from drops in accumulated to form undesirable lake substrates. Fish populations suffer from drops in dissolved oxygen associated with decaying algae and plant matter, the alteration of plant community composition, and poor habitat quality of the substrate (Wegener and Williams 1974). To remedy these problems in Florida lakes, the Florida Game and Fresh Water Fish Commission initiated a lake restoration program in 1971 which emphasizes the use of a lake draw down to expose sediments (GFC 95). The objective ofthe program is to reduce undesirable plant species, expand desirable plant communities, and consolidate flocculent organic sediments (Holcomb and Wegener 1971, Wegener et. al. 1974, Fox et. al. 1977, Cooke 1980, Tarver 1980, GFC 1995). In addition, muck removal operations following lake level draw downs are meant to resolve the problem of extensive build up of organic sediments (GFC 1995, Moyer et. al. 1995). The goal of the draw down and restoration activity is to improve aquatic habitat in support of fisheries and wildlife while improving lake quality for recreational usage (e.g. sport fishing) (Wegener and Williams 1974, Tarver 1980,. GFC 1995). The Florida Game and Fresh Water Fish Commission (GFC), in cooperation with the South Florida Water Management District (SFWMD), conducted a draw down of Lake Kissimmee from December 1995- June 1996, dropping lake levels by approximately 1.7 meters. The Lake Kissimmee draw down provided an excellent opportunity to investigate the impact of management techniques on an invertebrate which is a critical component of the central lakes food web, the Florida apple snail (Pomacea paludosa, SAY). Although data on the responses of some invertebrate species 2 to draw downs in central Florida are available (Wegener et. al. 1974, Fox et. al. 1977, Butler et. al. 1992), no published studies document the responses of P. paludosa. The Florida apple snail belongs to the tropical family of aquatic snails, Pilidae, which inhabitant wetland areas in Florida, Central and South America, Africa and India. Most Pilidae habitat typically (under natural hydrologic patterns) experiences a seasonal dry down, and the Florida apple snail is no exception. Pilidae snails utilize both a lung and gill for respiration (Andrews 1965). The dual respiratory system enables these animals to tolerate daily and seasonal dissolved oxygen fluctuations, permits egg-laying above water level (eggs thus avoid hypoxia and predation), and, in some Pilid species, enables adults to maintain aerobic respiration during the dry-season (McClary 1964, Burky et al. 1972, Aldridge 1983). Apple snails are critical components of lake food webs in Florida. They are prey to alligators (Alligator mississippiensis)( Delany and Abercrombie 1986), fish (Lepomis microlophus)(Chable 1947), turtles (Trionyxferox) (Dalrymple 1977), and ibis (Eudocimus albus)(Kushlan 1974). Apple snails comprise over 75% ofthe diet of the limpkins (Aramus guaraunaXCottam 1942), and nearly 100% ofthe diet of endangered snail kite (Rostramus sociabilis)(Snyder and Snyder 1969). Although the majority of the snail kite population occupies wetland habitats in south Florida throughout the year, they have been found to emigrate from this area when the dry season escalates into a prolonged drought (Beissinger and Takekawa 1983, Bennetts and Kitchens 1997). Researchers have identified the central lakes system as a critical refuge for the snail kite during these droughts (Beissinger and Takekawa 1983, Bennetts and Kitchens 1997). In 3 addition, the kites have been consistently nesting (even in non-drought years) on Lake Kissimmee and Lake Tohopekaliga since the early 1980's, providing further support (in the form of suitable foraging and nesting habitat) for the endangered kite population (Beissinger and Takekawa 1983, Bennetts and Kitchens 1997). The impetus for the Lake Kissimmee draw down is habitat improvement for fisheries and wildlife (GFC 1995). A conservation priority ranking system for Florida wildlife identifies the snail kite and limpkin, largely due to their specialized diet of apple snails, as deserving special attention for monitoring and management (Milsap et. a1. 1990).Moyer et a1. 1991 specifically recommended an evaluation ofthe impact of lake draw downs on apple snails. In this report we present the findings of a three-year study ofthe immediate and long term impacts ofthe Lake Kissimmee draw down and restoration activity on apple snail populations. The objectives ofthis research are as follows: • To study the impacts oflake restoration activity (e.g. draw down, muck removal) on snail populations in several sites throughout the lake by assessing pre-draw down and post-draw down snail abundance~ • To study the movement patterns of snails to find out what proportion ofthe population migrates to deeper water or become stranded in the dry down area as lake levels recede; • To study the capacity for snails to survive in dry down conditions (Document has 55 pages

Neuronal and non-neuronal signals regulate <i>Caernorhabditis elegans</i> avoidance of contaminated food

One way in which animals minimise the risk of infection is to reduce their contact with contaminated food. Here we establish a model of pathogen-contaminated food avoidance using the nematode worm Caernorhabditis elegans. We find that avoidance of pathogen-contaminated food protects C. elegans from the deleterious effects of infection and, using genetic approaches, demonstrate that multiple sensory neurons are required for this avoidance behaviour. In addition, our results reveal that avoidance of contaminated food requires bacterial adherence to non-neuronal cells in the tail of C. elegans that are also required for the cellular immune response. Previous studies in C. elegans have contributed significantly to our understanding of molecular and cellular basis of host-pathogen interactions and our model provides a unique opportunity to gain basic insights into how animals avoid contaminated food

Willingness to pay for locally produced foods: A customer intercept study of direct market and grocery store shoppers

Increasingly, grocery stores are marketing foods differentiated as locally produced. Freshness and taste are obvious reasons for consumer preference for these goods, but also important may be home-bias. Whatever the motive, there is substantial evidence that some consumers are willing to pay premium prices for food characterized as locally produced. A customer-intercept survey and a choice experiment of food shoppers in direct markets and traditional grocery stores was analyzed using Conjoint methods to evaluate WTP for characteristics related to locally grown fresh strawberries. Our results suggest that consumers are willing to pay more for locally produced berries: Customers intercepted in grocery stores would pay an average of 64 cents more per quart, while those intercepted at direct markets would pay nearly $1.17 more per carton of strawberries that was grown locally rather than berries identified simply as "produced in the U.S." These conclusions provide a solid rationale for the existence of niche market potential for local berry producers.Consumer/Household Economics,

Paclitaxel inhibits the activity and membrane localization of PKCα and PKCβI/II to elicit a decrease in stimulated calcitonin gene-related peptide release from cultured sensory neurons

Peripheral neuropathy is a dose-limiting and debilitating side effect of the chemotherapeutic drug, paclitaxel. Consequently, elucidating the mechanisms by which this drug alters sensory neuronal function is essential for the development of successful therapeutics for peripheral neuropathy. We previously demonstrated that chronic treatment with paclitaxel (3–5 days) reduces neuropeptide release stimulated by agonists of TRPV1. Because the activity of TRPV1 channels is modulated by conventional and novel PKC isozymes (c/nPKC), we investigated whether c/nPKC mediate the loss of neuropeptide release following chronic treatment with paclitaxel (300 nM; 3 and 5 days). Release of the neuropeptide, calcitonin gene-related peptide (CGRP), was measured as an index of neuronal sensitivity. Following paclitaxel treatment, cultured dorsal root ganglia sensory neurons were stimulated with a c/nPKC activator, phorbol 12,13-dibutyrate (PDBu), or a TRPV1 agonist, capsaicin, in the absence and presence of selective inhibitors of conventional PKCα and PKCβI/II isozymes (cPKC). Paclitaxel (300 nM; 3 days and 5 days) attenuated both PDBu- and capsaicin-stimulated release in a cPKC-dependent manner. Under basal conditions, there were no changes in the protein expression, phosphorylation or membrane localization of PKC α, βI or βII, however, paclitaxel decreased cPKC activity as indicated by a reduction in the phosphorylation of cPKC substrates. Under stimulatory conditions, paclitaxel attenuated the membrane translocation of phosphorylated PKC α, βI and βII, providing a rationale for the attenuation in PDBu- and capsaicin-stimulated release. Our findings suggest that a decrease in cPKC activity and membrane localization are responsible for the reduction in stimulated peptide release following chronic treatment with paclitaxel in sensory neurons

The effect of relative plasma plume delay on the properties of complex oxide films grown by multi-laser multi-target combinatorial pulsed laser deposition

We report the effects of relative time delay of plasma plumes on thin garnet crystal films fabricated by dual-beam, combinatorial pulsed laser deposition. Relative plume delay was found to affect both the lattice constant and elemental composition of mixed Gd3Ga5O12 (GGG) and Gd3Sc2Ga5O12 (GSGG) films. Further analysis of the plasmas was undertaken using a Langmuir probe, which revealed that for relative plume delays shorter than ~200 µs, the second plume travels through a partial vacuum created by the first plume, leading to higher energy ion bombardment of the growing film. The resulting in-plane stresses are consistent with the transition to a higher value of lattice constant normal to the film plane that was observed around this delay value. At delays shorter than ~10 µs, plume propagation was found to overlap, leading to scattering of lighter ions from the plume and a change in stoichiometry of the resultant films