High-use Areas Research Articles

Fifteen-year survival outcomes following primary androgen-deprivation therapy for localized prostate cancer.

One in 6 American men will be diagnosed as having prostate cancer during their lifetime. Although there are no data to support the use of primary androgen-deprivation therapy (ADT) for early-stage prostate cancer, primary ADT has been widely used for localized prostate cancer, especially among older patients. To determine the long-term survival impact of primary ADT in older men with localized (T1/T2) prostate cancer. This was a population-based cohort study of 66,717 Medicare patients 66 years or older diagnosed from 1992 through 2009 who received no definitive local therapy within 180 days of prostate cancer diagnosis. The study was conducted in predefined US geographical areas covered by the Surveillance, Epidemiology, and End Results (SEER) Program. Instrumental variable analysis was used to assess the impact of primary ADT and control for potential biases associated with unmeasured confounding variables. The instrumental variable comprised combined health services areas with various usage rates of primary ADT. The analysis compared survival outcomes in the top tertile areas with those in the bottom tertile areas. Prostate cancer-specific survival and overall survival. With a median follow-up of 110 months, primary ADT was not associated with improved 15-year overall or prostate cancer-specific survival following the diagnosis of localized prostate cancer. Among patients with moderately differentiated cancers, the 15-year overall survival was 20.0% in areas with high primary ADT use vs 20.8% in areas with low use (difference: 95% CI, -2.2% to 0.4%), and the 15-year prostate cancer survival was 90.6% in both high- and low-use areas (difference: 95% CI, -1.1% to 1.2%). Among patients with poorly differentiated cancers, the 15-year cancer-specific survival was 78.6% in high-use areas vs 78.5%, in low-use areas (difference: 95% CI, -1.8% to 2.4%), and the 15-year overall survival was 8.6% in high-use areas vs 9.2% in low-use areas (difference: 95% CI, -1.5% to 0.4%). Primary ADT is not associated with improved long-term overall or disease-specific survival for men with localized prostate cancer. Primary ADT should be used only to palliate symptoms of disease or prevent imminent symptoms associated with disease progression.

Spatial and temporal occurrence of blue whales off the U.S. West Coast, with implications for management.

Mortality and injuries caused by ship strikes in U.S. waters are a cause of concern for the endangered population of blue whales (Balaenoptera musculus) occupying the eastern North Pacific. We sought to determine which areas along the U.S. West Coast are most important to blue whales and whether those areas change inter-annually. Argos-monitored satellite tags were attached to 171 blue whales off California during summer/early fall from 1993 to 2008. We analyzed portions of the tracks that occurred within U.S. Exclusive Economic Zone waters and defined the ‘home range’ (HR) and ‘core areas’ (CAU) as the 90% and 50% fixed kernel density distributions, respectively, for each whale. We used the number of overlapping individual HRs and CAUs to identify areas of highest use. Individual HR and CAU sizes varied dramatically, but without significant inter-annual variation despite covering years with El Niño and La Niña conditions. Observed within-year differences in HR size may represent different foraging strategies for individuals. The main areas of HR and CAU overlap among whales were near highly productive, strong upwelling centers that were crossed by commercial shipping lanes. Tagged whales generally departed U.S. Exclusive Economic Zone waters from mid-October to mid-November, with high variability among individuals. One 504-d track allowed HR and CAU comparisons for the same individual across two years, showing similar seasonal timing, and strong site fidelity. Our analysis showed how satellite-tagged blue whales seasonally used waters off the U.S. West Coast, including high-risk areas. We suggest possible modifications to existing shipping lanes to reduce the likelihood of collisions with vessels.

Aligning conservation and research priorities for proactive species and habitat management: the case of dugongsDugong dugonin Johor, Malaysia

AbstractConservation efforts use scientific data to provide an adaptive framework wherein habitat and wildlife sustainability can co-exist with human activities. Good science informs decision-makers and facilitates the development of successful conservation approaches. However, conservation concerns for the dugongDugong dugonin South-east Asia are sufficiently urgent that action must be taken quickly, even though science has not provided complete answers to critical questions. In Johor, Malaysia, aerial surveys were conducted to assess dugong numbers, dugong high-use areas and overlap of dugong sightings with areas of seagrass. Dugong distribution included existing marine parks and locations where known conservation threats exist. We conclude that the Johor islands may represent a significant congregation site for dugongs in Peninsular Malaysia, with as many as 20 dugongs recorded in a single day. The existence of a marine park where the dugong sightings were most prominent is encouraging but only 38% of those sightings fell within the boundaries of the park. Anthropogenic threats need to be assessed and addressed prior to complex development activities such as dredging and coastal reclamation for tourism development in this critical area. We use this case to explore the concept of advancing species conservation through focused research and management, particularly where uncertainties exist because data are scarce.

Resource configuration and abundance affect space use of a cooperatively breeding resident bird

ABSTRACT Movement and space use of birds is driven by activities associated with acquiring and maintaining access to critical resources. Thus, the spatial configuration of resources within home ranges should influence bird movements, and resource values should be relative to their locations. We radio-tracked 22 Brown-headed Nuthatches (Sitta pusilla) and related their space use and home range sizes to available resources while taking nest site locations into account. We developed utilization distributions (UDs) from nuthatch locations, and treated the area of each 95% isopleth as home range size and the height of the UD as relative probability of use. We fit models relating home range size to mean resource measures within home ranges, and used lognormal regression to relate intensity of use to resource metrics at random points by ranking linear mixed models. Nuthatch home ranges typically had two centers of activity. Areas of high use were associated with the density of recently killed snags (likely a for...

Seasonal Resource Selection and Distributional Response by Elk to Development of a Natural Gas Field

Global energy demand is predicted to increase dramatically, suggesting the need to understand the role of disturbance from energy development better and to develop more efficient conservation strategies for affected wildlife populations. We evaluated elk (Cervus elaphus) response to disturbance associated with natural gas development in summer and winter, including shifts in resource selection and concomitant distribution. We collected elk locations prior to (1992–1995) and during (2008–2010) coal bed natural gas (CBNG) development in the ∼ 498-km2 Fortification Creek Area (FCA) of northeastern Wyoming, USA, where approximately 700 CBNG wells and 542 km of collector, local, and resource roads were developed from 2000 through 2010. We developed resource selection functions for summer and winter using coordinate data from VHF-collared female elk prior to CBNG development and similar location data from GPS-collared female elk during CBNG development to assess spatial selection shifts. By pooling across all locations we created population level models for each time period (e.g., pre- and during development) and incorporated individual variation through bootstrapping standard errors for parameter estimates. Comparison of elk resource selection prior to and during natural gas development demonstrated behavioral and distributional shifts whereby during development, elk demonstrated a higher propensity to use distance and escape cover to minimize exposure to roads. Specifically, during-development elk selected areas with greater Rocky Mountain juniper (Juniperus scopulorum Sarg.) cover, increased terrain ruggedness, and farther from CBNG roads than prior to development. Elk distributional changes resulting from avoidance behavior led to a loss of high-use areas by 43.1% and 50.2% in summer and winter, respectively. We suggest reducing traffic, protecting woody escape cover, and maintaining refugia within the energy-development footprint to promote persistence of elk within energy fields.

Use of a towed camera system to investigate benthic habitat use by inter-nesting female hawksbill sea turtles

The types of marine benthic habitats utilised by hawksbill sea turtles Eretmochelys imbricata nesting at Needham's Point, Barbados, were investigated using an underwater drop camera. Habitats used preferentially (i.e. those within high-use areas) tended to be high relief and densely covered with biota, characterised by high abundance of hard corals and shallower than less frequented areas. These structurally complex habitats offered opportunities for rest and refuge, but not for foraging, with females showing no preference for sites with high sponge abun- dance. Females appeared to trade off site quality (i.e. based on benthic relief, cover and species composition) against the energy expended to get there, travelling long distances (up to 21.2 km) to higher-quality sites.

A tradeoff frontier for global nitrogen use and cereal production

Nitrogen fertilizer use across the world’s croplands enables high-yielding agricultural production, but does so at considerable environmental cost. Imbalances between nitrogen applied and nitrogen used by crops contributes to excess nitrogen in the environment, with negative consequences for water quality, air quality, and climate change. Here we utilize crop input-yield models to investigate how to minimize nitrogen application while achieving crop production targets. We construct a tradeoff frontier that estimates the minimum nitrogen fertilizer needed to produce a range of maize, wheat, and rice production levels. Additionally, we explore potential environmental consequences by calculating excess nitrogen along the frontier using a soil surface nitrogen balance model. We find considerable opportunity to achieve greater production and decrease both nitrogen application and post-harvest excess nitrogen. Our results suggest that current (circa 2000) levels of cereal production could be achieved with ∼50% less nitrogen application and ∼60% less excess nitrogen. If current global nitrogen application were held constant but spatially redistributed, production could increase ∼30%. If current excess nitrogen were held constant, production could increase ∼40%. Efficient spatial patterns of nitrogen use on the frontier involve substantial reductions in many high-use areas and moderate increases in many low-use areas. Such changes may be difficult to achieve in practice due to infrastructure, economic, or political constraints. Increases in agronomic efficiency would expand the frontier to allow greater production and environmental gains.

A critical review of habitat use by feral cats and key directions for future research and management

Feral cats (Felis catus) have a wide global distribution and cause significant damage to native fauna. Reducing their impacts requires an understanding of how they use habitat and which parts of the landscape should be the focus of management. We reviewed 27 experimental and observational studies conducted around the world over the last 35 years that aimed to examine habitat use by feral and unowned cats. Our aims were to: (1) summarise the current body of literature on habitat use by feral and unowned cats in the context of applicable ecological theory (i.e. habitat selection, foraging theory); (2) develop testable hypotheses to help fill important knowledge gaps in the current body of knowledge on this topic; and (3) build a conceptual framework that will guide the activities of researchers and managers in reducing feral cat impacts. We found that feral cats exploit a diverse range of habitats including arid deserts, shrublands and grasslands, fragmented agricultural landscapes, urban areas, glacial valleys, equatorial to sub-Antarctic islands and a range of forest and woodland types. Factors invoked to explain habitat use by cats included prey availability, predation/competition, shelter availability and human resource subsidies, but the strength of evidence used to support these assertions was low, with most studies being observational or correlative. We therefore provide a list of key directions that will assist conservation managers and researchers in better understanding and ameliorating the impact of feral cats at a scale appropriate for useful management and research. Future studies will benefit from employing an experimental approach and collecting data on the relative abundance and activity of prey and other predators. This might include landscape-scale experiments where the densities of predators, prey or competitors are manipulated and then the response in cat habitat use is measured. Effective management of feral cat populations could target high-use areas, such as linear features and structurally complex habitat. Since our review shows often-divergent outcomes in the use of the same habitat components and vegetation types worldwide, local knowledge and active monitoring of management actions is essential when deciding on control programs.

Impact of Regular Collaboration Between Infectious Diseases and Critical Care Practitioners on Antimicrobial Utilization and Patient Outcome*

Antimicrobial stewardship programs have been shown to help reduce the use of unnecessary antimicrobial agents in the hospital setting. To date, there has been very little data focusing on high-use areas, such as the medical ICU. A prospective intervention was done to assess guideline compliance, antimicrobial expenditure, and healthcare cost when an infectious disease fellow interacts regularly with the medical ICU team. A 3-month retrospective chart review was followed by a 3-month prospective intervention the following year. Two hundred forty-six total charts were reviewed to assess generally accepted guideline compliance, demographics, and microbiologic results. Twenty-four-bed medical ICU at an 861-bed tertiary care, university teaching hospital in North Carolina. Patients receiving antibiotics in the medical ICU. During the intervention period, the infectious disease fellow reviewed the charts, including physician notes and microbiology data, and discussed antimicrobial use with the medical ICU team. Antimicrobial use, treatment duration, Acute Physiology and Chronic Health Evaluation II scores, length of stay, mechanical ventilation days, and mortality rates were compared during the two periods. No baseline statistically significant differences in the two groups were noted (i.e., age, gender, race, or Acute Physiology and Chronic Healthcare Evaluation II scores). Indications for antibiotics included healthcare-associated (53%) and community-acquired pneumonias (17%). Significant reductions were seen in extended-spectrum penicillins (p=0.0080), carbapenems (p=0.0013), vancomycin (p=0.0040), and metronidazole (p=0.0004) following the intervention. Antimicrobial modification led to an increase in narrow-spectrum penicillins (p=0.0322). The intervention group had a significantly lower rate of treatments that did not correspond to guidelines (p<0.0001). There was a reduction in mechanical ventilation days (p=0.0053), length of stay (p=0.0188), and hospital mortality (p=0.0367). The annual calculated healthcare savings was $89,944 in early antibiotic cessation alone. Active communication with an infectious disease practitioner can significantly reduce medical ICU antibiotic overuse by earlier modification or cessation of antibiotics without increasing mortality. This in turn can reduce healthcare costs, foster prodigious education, and strengthen relations between the subspecialties.

Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems: a spatial approach

The introduced feral cat (Felis catus) is a widespread generalist with flexible social behaviour and an apex predator without major interspecific competitors in insular ecosystems that evolved in the absence of predators. Mechanistic definitions consider an animal’s home range to be the spatial expression of a cognitive map that is kept up-to-date with the status of critical resources that contribute to animal fitness. We assumed there are two major determinants structuring the home range of cats as apex predators in insular ecosystems: the distribution of critical food resources and conspecific distribution. We hypothesized that cats structure their home ranges by optimizing the use of staple critical food resources and that as a consequence of the presence of rich resources cats tend to socialise, aggregate and share space. We carried out spatial analyses using location data for feral cats tracked using lightweight GPS collars in conjunction with the suitability value of rabbit patches and their associated ownership costs for cats within a New Zealand braided-river environment. Cat home ranges and spatial distribution, especially for females, were related to the inclusion of rabbit patches within home ranges with higher mean value than the average of neighbourhood patches in the landscape. Cats showed solitary behaviour but tolerance to conspecific presence by sharing high-use areas and high-value rabbit patches, mostly at different times, resulting in occasional encounters among males and females. Home range size and patterns of spatial overlap were dependant on sex and season. Solitary spacing patterns as consequence of innate preferences together with resource constraints may regulate feral cat population densities.

High-use areas, seasonal movements and dive patterns of juvenile loggerhead sea turtles in the Southwestern Atlantic Ocean

Characterizing the behaviors of sea turtles and identifying high-use areas as they vary in time and space is important for conservation planning, particularly when turtles overlap with fisheries that may unintentionally harm them. Between July 2006 and March 2010, 27 satel- lite transmitters were deployed at sea on juvenile loggerheads Caretta caretta captured as bycatch in the Uruguayan and Brazilian pelagic longline fisheries operating in the Southwestern Atlantic Ocean. Tracking duration ranged from 3 to 639 d (mean ± SD: 259 ± 159 d; n = 27), during which turtles moved between latitudes of 25 to 45° S and longitudes 35 to 54° W. High-use areas for the tracked turtles were over the continental shelf and slope within the Uruguayan, Argentin- ian, and Brazilian exclusive economic zones and in adjacent international waters. Diving informa- tion was available for 5 turtles. The maximum dive depth recorded varied between 100 and 300 m. Two turtles demonstrated potential bottom-feeding behaviors by diving to depths that corre- sponded closely with the depth of the seafloor (<200 m) at their given location. The sea surface temperature encountered by tagged turtles was on average 19.8 ± 2.3°C (range: 10.2 to 28.4°C), and turtles showed an affinity for waters supporting moderate to high primary productivity levels (0.43 ± 0.89 mg m �3 chlorophyll a). Latitudinal movements varied by season and sea surface tem- perature. These findings, along with those of other studies conducted in the region, demonstrate the need to strengthen ongoing collaborative efforts between neighboring countries and other international partnerships to further the research and management of sea turtles in this area.

Quantifying fine-scale resource selection by introduced European hedgehogs (Erinaceus europaeus) in ecologically sensitive areas

Introduced predators are important drivers of ecosystem change and can threaten native species. The European hedgehog (Erinaceus europaeus) was introduced from Britain into New Zealand where it is currently widespread, including in braided-river environments of the interior cold drylands where it might threaten native species such as riparian ground-nesting birds. The establishment of hedgehogs in braided-river environments may be facilitated by adjacent pastoral landscapes that provide food, primarily invertebrates, and dry shelter. Forays by hedgehogs into native prey habitats, such as riverbed floodplains, increase predation pressure. Understanding the spatial ecology of introduced predators can improve effectiveness of control measures. We assessed spatial resource selection by hedgehogs in a braided-river environment by tracking 27 individuals for 4–8 days in summer and autumn using microGPS-backpacks. We extracted fine-scale landscape variables from a map created using very high resolution satellite imagery to model home range placement within the study area. We also assessed habitat composition and ranking within high-use areas using compositional analysis. Hedgehogs established home ranges in pastoral landscapes containing abundant edges and high vegetation productivity (mainly green pastures and shrubs), and selected pastures and patches of shrubs as high-use areas. Hedgehogs avoided riverbed floodplains, suggesting that reported predation events on ground-nesting birds might be a consequence of secondary predation or individual specialization. We recommend that predation of native species by hedgehogs might be best alleviated if trapping is focused on those areas selected by native fauna of conservation concern (e.g. riverbed floodplains), as well some biologically-determined buffer surrounding these sites.

Ecological risk assessment of atrazine in North American surface waters

The triazine herbicide atrazine (2-chloro-4-ethylamino-6-isopropyl-amino-s-triazine) is one of the most used pesticides in North America. Atrazine is principally used for control of certain annual broadleaf and grass weeds, primarily in corn but also in sorghum, sugarcane, and, to a lesser extent, other crops and landscaping. Atrazine is found in many surface and ground waters in North America, and aquatic ecological effects are a possible concern for the regulatory and regulated communities. To address these concerns an expert panel (the Panel) was convened to conduct a comprehensive aquatic ecological risk assessment. This assessment was based on several newly suggested procedures and included exposure and hazard subcomponents as well as the overall risk assessment. The Panel determined that use of probabilistic risk assessment techniques was appropriate. Here, the results of this assessment are presented as a case study for these techniques. The environmental exposure assessment concentrated on monitoring data from Midwestern watersheds, the area of greatest atrazine use in North America. This analysis revealed that atrazine concentrations rarely exceed 20 μg/L in rivers and streams that were the main focus of the aquatic ecological risk assessment. Following storm runoff, biota in lower-order streams may be exposed to pulses of atrazine greater than 20 μg/L, but these exposures are short-lived. The assessment also considered exposures in lakes and reservoirs. The principal data set was developed by the U.S. Geological Survey, which monitored residues in 76 Midwestern reservoirs in 11 states in 1992-1993. Residue concentrations in some reservoirs were similar to those in streams but persisted longer. Atrazine residues were widespread in reservoirs (92% occurrence), and the 90th percentile of this exposure distribution for early June to July was about 5 μg/L. Mathematical simulation models of chemical fate were used to generalize the exposure analysis to other sites and to assess the potential effects of reduction in the application rates. Models were evaluated, modified, and calibrated against available monitoring data to validate that these models could predict atrazine runoff. PRZM-2 overpredicted atrazine concentrations by about an order of magnitude, whereas GLEAMS underpredicted by a factor of 2 to 5. Thus, exposure models were not used to extrapolate to other regions of atrazine use in this assessment. The effects assessment considered both freshwater and saltwater toxicity test results. Phytoplankton were the most sensitive organisms, followed, in decreasing order of sensitivity, by macrophytes, benthic invertebrates, zooplankton, and fish. Atrazine inhibits photophosphorylation but typically does not result in lethality or permanent cell damage in the short term. This characteristic of atrazine required a different model than typically used for understanding the potential impact in aquatic systems, where lethality or nonreversible effects are usually assumed. In addition, recovery of phytoplankton from exposure to 5 to 20 μg/L atrazine was demonstrated. In some mesocosm field experiments, phytoplankton and macrophytes were reduced after atrazine exposures greater than 20 μg/L. However, populations were quickly reestablished, even while atrazine residues persisted in the water. Effects in field studies were judged to be ecologically important only at exposures of 50 μg/L or greater. Mesocosm experiments did not reveal disruption of either ecosystem structure or function at atrazine concentrations typically encountered in the environment (generally 5 μg/L or less). Based on an integration of laboratory bioassay data, field effects studies, and environmental monitoring data from watersheds in high-use areas in the Midwestern United States, the Panel concluded that atrazine does not pose a significant risk to the aquatic environment. Although some inhibitory effects on algae, phytoplankton, or macrophyte production may occur in small streams vulnerable to agricultural runoff, these effects are likely to be transient, and quick recovery of the ecological system is expected. A subset of surface waters, principally small reservoirs in areas with intensive use of atrazine, may be at greater risk of exposure to atrazine. Therefore, it is recommended that site-specific risk assessments be conducted at these sites to assess possible ecological effects in the context of the uses to which these ecosystems are put and the effectiveness and cost-benefit aspect of any risk mitigation measures that may be applied.

Range and primary habitats of Hawaiian insular false killer whales: informing determination of critical habitat

For species listed under the US Endangered Species Act, federal agencies must des- ignate 'critical habitat', areas containing features essential to conservation and/or that may require special management considerations. In November 2010, the National Marine Fisheries Service proposed listing a small demographically isolated population of false killer whales Pseudorca crassidens in Hawai'i as endangered but has not yet proposed designating critical habitat. We assessed the population's range and heavily used habitat areas using data from 27 satellite tag deployments. Assessment of independence of individuals with temporally overlap- ping data indicated that data were from 22 'groups'. Further analyses were restricted to 1 individ- ual per group. Tag data were available for periods of between 13 and 105 d (median = 40.5 d), with 8513 locations (93.4% from JulyJanuary). Analyses of photo-identification data indicated that the population is divided into 3 large associations of individuals (social clusters), with tag data from 2 of these clusters. Ranges for these 2 clusters were similar, although one used significantly deeper waters, and their high-use areas differed. A minimum convex polygon range encompassing all locations was ~82 800 km 2 , with individuals ranging from Ni'ihau to Hawai'i Island and up to 122 km offshore. Three high-use areas were identified: (1) off the north half of Hawai'i Island, (2) north of Maui and Moloka'i and (3) southwest of Lana'i. Although this analysis provides informa- tion useful for decision-making concerning designation of critical habitat, there are likely other high-use areas that have not yet been identified due to seasonal limitations and availability of data from only 2 of the 3 main social clusters.

Coordinated nocturnal behavior of foraging jumbo squid Dosidicus gigas

We used split-beam acoustic techniques to observe free-swimming of jumbo squid Dosidicus gigas during 4 cruises in the Gulf of California. Four-dimensional spatio-temporal data revealed that at night in shallow water, jumbo squid were using ascending, spiral-like swimming paths to emerge from extremely dense aggregations, and were likely foraging on potential prey that were found overlapping in depth with their tracks. Within small regions at the vertices of these swimming paths, individual squid swam back and forth repetitively before continuing their ascent. The behaviors observed in these high-use regions, described using density kernel statis- tics, are consistent with other observations of prey capture behavior by squid. Often, the observed swimming paths of individual squid were found to parallel those of other squid in depth over time. In addition to being coordinated in depth, movements of individuals within a group of up to 40 individuals were coordinated in horizontal space so that high-use areas were overlapping in hor- izontal space but separated vertically. The resulting groups of tracks look like interwoven multiple helices anchored at their vertices by bouts of presumed feeding. These highly polarized, complex, coordinated movement patterns constitute schooling. Polarization in these groups did not break down during apparent feeding events as has been observed in other species. In fact, the feeding events themselves may define the anchor for group behavior. Schooling of jumbo squid school will likely be critical in understanding many aspects of their biology.

Estimation of Upper Centile Concentrations Using Historical Atrazine Monitoring Data from Community Water Systems

A survey sampling approach is presented for estimating upper centiles of aggregate distributions of surface water pesticide measurements obtained from datasets with large sample sizes but variable sampling frequency. It is applied to three atrazine monitoring programs of Community Water Systems (CWS) that used surface water as their drinking water source: the nationwide Safe Drinking Water Act (SDWA) data, the Syngenta Voluntary Monitoring Program (VMP), and the Atrazine Monitoring Program (AMP).The VMP/AMP CWS were selected on the basis of atrazine monitoring history (CWS having at least one annual average concentration from SDWA ≥ 1.6 ppb atrazine since 1997 in the AMP). Estimates of the raw water 95th, 99th, and 99.9th centile atrazine concentrations for the VMP/AMP CWS are 4.82, 11.85, and 34.00 ppb, respectively. The corresponding estimates are lower for the finished drinking water samples, with estimates of 2.75, 7.94, and 22.66 ppb, respectively. Finished water centile estimates for the VMP/AMP CWS using only the SDWA data for these sites are consistent with the results. Estimates are provided for the April through July period and for CWS based on surface water source type (static, flowing, or mixed). Requisite sample sizes are determined using statistical tolerance limits, relative SE, and the Woodruff interval sample size criterion. These analyses provide 99.9% confidence that the existing data include the 99.9th centile atrazine concentration for CWS raw and finished water in the Midwest atrazine high-use areas and in the nationwide SDWA dataset. The general validity of this approach is established by a simulation that shows estimates to be close to target quantities for weights based on sampling probabilities or time intervals between samples. Recommendations are given for suitable effective sample sizes to reliably determine interval estimates.

685 OUTCOMES OF RADIOTHERAPY AMONG MEN WITH LOW-RISK LOCALIZED PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Localized III1 Apr 2012685 OUTCOMES OF RADIOTHERAPY AMONG MEN WITH LOW-RISK LOCALIZED PROSTATE CANCER Grace Lu-Yao, Sung Kim, Dirk Moore, Weichung Shih, Yong Lin, Robert DiPaola, Anthony Zietman, Hui Li, Yu-Hsuan Shao, and Siu-Long Yao Grace Lu-YaoGrace Lu-Yao New Brunswick, NJ More articles by this author , Sung KimSung Kim New Brunswick, NJ More articles by this author , Dirk MooreDirk Moore New Brunswick, NJ More articles by this author , Weichung ShihWeichung Shih New Brunswick, NJ More articles by this author , Yong LinYong Lin New Brunswick, NJ More articles by this author , Robert DiPaolaRobert DiPaola New Brunswick, NJ More articles by this author , Anthony ZietmanAnthony Zietman Boston, MA More articles by this author , Hui LiHui Li New Brunswick, NJ More articles by this author , Yu-Hsuan ShaoYu-Hsuan Shao New Brunswick, NJ More articles by this author , and Siu-Long YaoSiu-Long Yao New Brunswick, NJ More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.768AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Although radiotherapy is commonly employed for localized prostate cancer, little data exist regarding whether primary radiotherapy lowers the risk of mortality, metastases, or usage of secondary androgen deprivation therapy (ADT). METHODS A population-based cohort study was performed using Medicare data linked to Surveillance, Epidemiology, and End Results cancer data to evaluate outcomes in 56,657 men aged 65-85 years treated with either primary radiotherapy or surveillance for T1-T2 prostate cancer diagnosed in 1992-2007. Instrumental variable analysis (IVA), a pseudo-randomization technique that captures the randomness associated with geographic variation in the use of radiotherapy was utilized to control for overt and hidden confounders. Secondary ADT was defined as the use of ADT beyond 3 years of cancer diagnosis. RESULTS Radiotherapy use was common among low-risk patients and there was wide geographic variation in utilization. For low-risk group, 10-year disease specific mortality in high- and low radiotherapy areas is identical (5.7% vs. 5.7%; hazard ratio [HR] =1.00; 95% CI 0.82-1.22) and the overall mortality is higher in high-radiotherapy areas (HR=1.06, 95% CI 1.02 – 1.11). In addition radiotherapy was not associated with a lower 10-year risk of secondary ADT use (23.2% in high-use areas, 22.5% in low-use areas at 10-year, HR=1.04, 95% C.I. 0.89-1.20) or metastasis (15.1% in high-use areas, 12.8% in low-use areas at 10-year, HR=1.20, 95% CI 0.97-1.49). CONCLUSIONS In patients aged 65-85 years with low-risk prostate cancer, primary radiotherapy does not reduce mortality, secondary ADT use, or metastases. The potential risks and benefits of radiotherapy and other therapies should be considered when making treatment decisions for localized prostate cancer. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e279 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Grace Lu-Yao New Brunswick, NJ More articles by this author Sung Kim New Brunswick, NJ More articles by this author Dirk Moore New Brunswick, NJ More articles by this author Weichung Shih New Brunswick, NJ More articles by this author Yong Lin New Brunswick, NJ More articles by this author Robert DiPaola New Brunswick, NJ More articles by this author Anthony Zietman Boston, MA More articles by this author Hui Li New Brunswick, NJ More articles by this author Yu-Hsuan Shao New Brunswick, NJ More articles by this author Siu-Long Yao New Brunswick, NJ More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Steller sea lion spatial‐use patterns derived from a Bayesian model of opportunistic observations

AbstractDespite acquisition of a substantial catalog of telemetry data from Steller sea lions (Eumetopias jubatus) over the past two decades, scientists still lack comprehensive regionally explicit knowledge about Steller sea lion habitat use. The Platforms of Opportunity data contain records of Steller sea lion sightings throughout the species’ entire range and have potential to fill gaps in knowledge about their spatial use; however, the data have not previously been used because effort (e.g., time spent surveying or area sampled) was not recorded when sightings were obtained. For this study a novel approach was used to overcome the lack of effort data through development of an effort index and a Bayesian negative binomial model. The model quantified Steller sea lion encounter rates and associated uncertainty within 15 × 15 km2 grid cells across the species’ entire range. Year‐round, as well as breeding and nonbreeding season encounter rates were estimated. The results of this analysis identify several previously undocumented areas of high use by Steller sea lions, indicate that only 37% of Steller sea lion high‐use areas fall within designated critical habitat, and demonstrate that use of depth and distance from shore as indicators of Steller sea lion habitat is contraindicated.

Use of SOFEA to Predict 1,3‐D Concentrations in Air in High‐Use Regions of California

Methyl bromide, a commonly used soil fumigant, is being phased out per the Montreal Protocol and multiple fumigants are being positioned as replacements. Most effective soil fumigants, including methyl bromide, have the potential for inhalation exposure if the material volatilizes from soil. Chronic exposures for the fumigant 1,3-dichloropropene (1,3-D) are managed in part by the California Department of Pesticide Regulation by limiting the annual amount that can be used within a given township. A stochastic/deterministic numerical system (SOil Fumigant Exposure Assessment system [SOFEA]) was developed using the USEPA air dispersion model ISCST3, field study observations for flux loss, and links to Geographic Information Systems (GIS). SOFEA was used retrospectively to simulate concentrations of 1,3-D in air for direct comparison with monitoring program observations conducted by California Air Resources Board in Fresno County. These results indicated slight overprediction but correct magnitudes for regional air concentrations, especially at the higher percentiles, and provide a performance test. SOFEA was also used, prospectively, to predict air concentrations in potential future-use scenarios. These simulations of chronic air concentrations in two high-use 1,3-D counties of California (Ventura, Merced) consisted of 25 contiguous townships treated either at 1.5 times the current township allocation (40,937 kg) or at the maximum levels of 1,3-D used between 1999 and 2006. Exposure predictions for large regions are necessary to evaluate chronic population-based lifetime exposure and risk to 1,3-D should use patterns change. SOFEA provides a tool to estimate regional air concentrations within high-use areas required for such risk assessments.

Large-scale movements and high-use areas of western Pacific leatherback turtles,Dermochelys coriacea

The western Pacific leatherback turtle (Dermochelys coriacea), one of three genetically distinct stocks in the Indo-Pacific region, has declined markedly during past decades. This metapopulation nests year-round at beaches of several western Pacific island nations and has been documented through genetic analysis and telemetry studies to occur in multiple regions of the Pacific Ocean. To provide a large-scale perspective of their movements, high-use areas, and habitat associations, we report and synthesize results of 126 satellite telemetry deployments conducted on leatherbacks at western Pacific nesting beaches and at one eastern Pacific foraging ground during 2000–2007. A Bayesian switching state-space model was applied to raw Argos-acquired surface locations to estimate daily positions and behavioral mode (either transiting or area-restricted search) for each turtle. Monthly areas of high use were identified for post-nesting periods using kernel density estimation. There was a clear separation of migratory destinations for boreal summer vs. boreal winter nesters. Leatherbacks that nested during boreal summer moved into Large Marine Ecosystems (LMEs) of the temperate North Pacific Ocean or into tropical waters of the South China Sea. Turtles that nested during boreal winter moved into temperate and tropical LMEs of the southern hemisphere. Area-restricted search occurred in temperate and tropical waters at diverse pelagic and coastal regions exhibiting a wide range of oceanographic features, including mesoscale eddies, coastal retention areas, current boundaries, or stationary fronts, all of which are known mechanisms for aggregating leatherback prey. Use of the most distant and temperate foraging ground, the California Current LME, required a 10–12 month trans-Pacific migration and commonly involved multiple years of migrating between high-latitude summer foraging grounds and low-latitude eastern tropical Pacific wintering areas without returning to western Pacific nesting beaches. In contrast, tropical foraging destinations were reached within 5–7 months and appeared to support year-round foraging, potentially allowing a more rapid return to nesting beaches. Based on these observations, we hypothesize that demographic differences are likely among nesting females using different LMEs of the Indo-Pacific. The differences in movements and foraging strategies underscore the importance of and the need for ecosystem-based management and coordinated Pacific-wide conservation efforts.