Temperature-dependent prey capture efficiency and foraging modes of brown trout Salmo trutta

Prey capture success and foraging mode were studied in brown trout Salmo trutta at temperatures ranging from 5.7 to 14.0° C. At low temperatures, there was a positive correlation between prey capture success and the proportion of time that the fish spent holding feeding stations. This correlation was not found at temperatures >10° C.

Impact of ant control technologies on insecticide runoff and efficacy

BACKGROUND

Insecticides are commonly used for ant control around residential homes, but post-treatment runoff may contribute to contamination of surface water in urban watersheds. This study represents the first instance where runoff of insecticides was directly measured after applications around single family residences. During 2007, houses were treated with bifenthrin or fipronil sprays following standard practices. During 2008, pin stream applicators, spray-free zones and restricting sprays to the house foundation were considered as management options.

RESULTS

During 2007, the resulting runoff from the bifenthrin spray in the irrigation water had a mean concentration of 14.9 microg L(-1) at 1 week post-treatment and 2.5 microg L(-1) at 8 weeks, both high enough to be toxic to sensitive aquatic organisms. In comparison, treatments with bifenthrin granules resulted in no detectable concentrations in the runoff water after 8 weeks. The mean concentration for fipronil used as a perimeter spray was 4.2 microg L(-1) at 1 week post-treatment and 0.01 microg L(-1) at 8 weeks, with the first value also suggesting a potential for causing acute aquatic toxicity to sensitive organisms. During 2008, insecticide runoff was reduced by using spray-free zones and pin stream perimeter applications.

CONCLUSIONS

It is shown that insecticide runoff from individual home treatments for ants can be measured and used to improve techniques that minimize runoff. The pin stream application and applications limited to the house foundation should be further evaluated for their potential to reduce pesticide runoff from residential homes.

Genetic component of bee odor in kin recognition

The primitively social sweat bee, Lasioglossum zephyrum, blocks the entry into its nest of most conspecifics from other colonies. Laboratory inbreeding of these bees produced lines which showed a positive linear relationship between the coefficient of relationship of bees tested and how often they permitted non-nestmates to pass them. The most probable mechanism is a genetically determined odor coupled with a learned component by which guard bees discriminate between odors of close kin and other bees.

Efficacy and cardiac safety of adjuvant trastuzumab-based chemotherapy regimens for HER2-positive early breast cancer

BACKGROUND

Trastuzumab-based adjuvant therapy has become the standard of care for human epidermal growth factor receptor-2 (HER2)-positive early breast cancer (EBC). Both anthracycline- and non-anthracycline-containing trastuzumab regimens are approved in the United States, but cardiotoxicity is increased with anthracycline-containing regimens.

DESIGN

This paper reviews published and reported efficacy and cardiac safety data from the adjuvant trastuzumab trials [National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31/North Central Cancer Treatment Group (NCCTG) N9831, Breast Cancer International Research Group (BCIRG) 006, Herceptin Adjuvant (HERA), FinHer, and Programme Adjuvant Cancer Sein (PACS) 04].

RESULTS

The addition of trastuzumab to adjuvant chemotherapy significantly improved disease-free survival (from 24% to 58%) in five of the six trials. Overall survival was significantly improved (23%-35%) in the large trials. In NSABP B-31/ NCCTG N9831, 5.0%-6.6% of patients who received doxorubicin and cyclophosphamide (AC) were unable to receive trastuzumab. Cardiac event rate was highest in the anthracycline-containing trastuzumab arms (1.9%-3.8%) and lowest with the regimen of docetaxel, carboplatin, and trastuzumab (TCH) (0.4%).

CONCLUSIONS

Incorporation of trastuzumab into anthracycline and non-anthracycline adjuvant chemotherapy regimens has substantially improved outcomes in HER2-postive EBC. The TCH regimen has the lowest rates of cardiac dysfunction, but uncertainty exists regarding the relative efficacy of TCH compared with anthracycline-containing trastuzumab regimens. Cardiac risk factor assessment can aid in selection of trastuzumab-based adjuvant therapy regimens.

Queen sex pheromone of the slave-making ant, Polyergus breviceps

Workers of the slave-making ant, Polyergus breviceps, raid nests of Formica ants and return with Formica pupae that mature into worker ants in the slave-makers' colony. These Formica workers then tend the Polyergus brood, workers, and reproductives. During raids in the mating season, winged virgin Polyergus queens accompany the workers in the raiding columns. During the raid, the virgin queens release a pheromone that attracts males that quickly mate with the queens. We report the identification, synthesis, and bioassay of the sex attractant pheromone of the queens as an approximately 1:6 ratio of (R)-3-ethyl-4-methylpentan-1-ol and methyl 6-methylsalicylate. The ants produce exclusively the (R)-enantiomer of the alcohol, and the (S)-enantiomer has no biological activity, neither inhibiting nor increasing attraction to blends of methyl 6-methylsalicylate with the (R)-enantiomer.

Aggressive interactions between Solenopsis invicta and Linepithema humile (Hymenoptera: Formicidae) under laboratory conditions

The Argentine ant, Linepithema humile (Mayr), and the red imported fire ant, Solenopsis invicta Buren, are natural agonists in their country of origin. Since the first report of L. humile in California in 1907 its range expanded statewide, displacing native ant species wherever it spread. Since the discovery of established populations of S. invicta in southern California in 1998, it has been restricted to discrete areas of southern California. However, as these discrete populations expand, they are encountering large populations of L. humile, which are effective competitors for available resources and are particularly aggressive in their encounters with other ant species such as S. invicta. Most Dolichoderine ants such as L. humile do not prefer to forage on baits made with defatted corn grit and soybean oil typically used in red imported fire ant control programs. Applications of these baits in areas where distributions of these species overlap might selectively affect populations of S. invicta and give L. humile a competitive advantage. Three laboratory experiments were conducted to determine the competitive outcomes between S. invicta pitted against L. humile: 1) agonistic behavior of workers in small arenas, 2) colony interactions with different population ratios, and 3) the effects of pyriproxyfen on the competitiveness of S. invicta against L. humile. Populations of S. invicta consisting of major workers killed more L. humile than did minors or a mixture of majors and minors. When paired against L. humile colonies consisting of 1,100 workers, colonies consisting of 38 S. invicta workers were easily defeated by L. humile. Colonies consisting of 450 S. invicta workers plugged their nest entrances, but they were ultimately defeated by L. humile after 13 d. The S. invicta colonies consisting of 1,100 workers took control of the bridge connecting the colonies, invaded the L. humile colony, killed the Argentine ant queens, and removed their brood. Pyriproxyfen-treated fire ant workers took significantly longer to chase the Argentine ants from a connecting bridge than did untreated fire ants. Thus, fire ant baits may have long-term effects on intercolonial aggression between S. invicta and L. humile, especially when Argentine ant populations are high in the summer.

Response of Argentine ants and red imported fire ants to permethrin-impregnated plastic strips: foraging rates, colonization of potted soil, and differential mortality

This study investigated the effects of the permethrin-impregnated plastic on ant mortality and foraging rates, and tested its potential for preventing ants from colonizing potted soil. Direct exposure to the plastic for as short as 1 min caused significant mortality of both red imported fire ants, Solenopsis invicta Buren, and Argentine ants, Linepithema humile (Mayr); however, red imported fire ants were more susceptible than Argentine ants. Knockdown of virtually all ants initially occurred within 15 min after exposure. However, some moribund ants recovered from the effects within 24 h. For example, after 1 min of direct exposure to the permethrin-impregnated plastic, 70% of Argentine ants and 5% of red imported fire ants recovered from the treatment. In established colonies of Argentine ants, significantly fewer ants foraged for food up posts treated with the plastic compared with untreated posts. In addition, colonies responded to introduction of the treatment by significantly reducing their overall foraging rates, even on untreated posts. When pots filled with moistened soil were introduced into established ant colonies, 82% of Argentine ants and 99% of red imported fire ants moved into the soil. In contrast, when a 1-cm-wide coil of the plastic was placed under the pot, no ants moved into the soil. The potential for use of these materials in nursery production is discussed.

Sex Pheromone of Queens of the Slave-Making Ant, Polyergus breviceps

The sex attractant pheromone produced in mandibular glands of queens of the slave-making ant Polyergus breviceps has been identified as a blend of methyl 6-methylsalicylate and 3-ethyl-4-methylpentanol. In field trials, each compound alone was completely unattractive to males, whereas blends of the two compounds attracted hundreds of males within a couple of hours.

Assessing an educational intervention to improve physician violence screening skills

OBJECTIVES

Health professionals play an integral role in assessing the risk of violence in their patients. However, there have been few evaluations of violence prevention education programs for health care personnel. The objective of this study was to evaluate the effects of a violence-screening education program on pediatric residents' and medical students' comfort level and skills in the identification and management of violence risks.

SETTING

Adolescent clinic of a tertiary care pediatric hospital.

PARTICIPANTS

Fifty-six second-year residents and third-year medical students assigned to a 4-week adolescent clinic rotation.

DESIGN

Randomized, controlled comparison study conducted over a 1-year period.

INTERVENTION

On alternate months, medical students and residents in the intervention group participated in a 3-hour workshop on violence prevention. The workshop included a didactic session with an overview of firearm, media, and sexual violence; a discussion of risk factors for adolescent violence; and training on the approach to the adolescent interview. Participants also discussed violence risks in the community with a panel of teen health educators, engaged in one-on-one role play with the youth educators, and received feedback on their violence screening skills. The control group received the standard ambulatory clinic manual with articles on violence prevention.

EVALUATION METHODS

All participants completed prerotation and postrotation questionnaires assessing their self-reported screening practices, as well as perceived importance and confidence in violence screening. Participants also interviewed and examined an adolescent standardized patient (SP) in the clinic. SPs completed evaluations on the content of the residents' and students' screening, their interpersonal skills, and their skill in the identification and management of the violence-related problem.

RESULTS

Over 12 months, 30 control and 26 intervention participants were recruited. There were no differences in prerotation questionnaire scores for intervention and control groups in screening practices, perceived importance and confidence in violence screening. Postrotation intervention participants reported more screening compared with controls on violence in school/neighborhood and fighting history. There was also greater perceived importance in asking about access/use of weapons and violence in school/neighborhood. Intervention participants also had improved performance compared with controls on SP evaluations of screening for violence, identification and management of the violence-related scenario, and interpersonal skills.

CONCLUSION

A violence prevention education program with teen health educators improved participants' self-reported violence questioning, as well as increased perceived comfort and importance in violence screening. Participants in the program also improved their identification and management of a standardized violence-related scenario presented in an adolescent clinic setting. adolescent violence, physician education, violence risk screening.

Considerations in choosing a primary endpoint that measures durability of virological suppression in an antiretroviral trial

OBJECTIVES

At present, many clinical trials of anti-HIV-1 therapies compare treatments by a primary endpoint that measures the durability of suppression of HIV-1 replication. Several durability endpoints are compared.

DESIGN

Endpoints are compared by their implicit assumptions regarding surrogacy for clinical outcomes, sample size requirements, and accommodations for inter-patient differences in baseline plasma HIV-1-RNA levels and in initial treatment response.

METHODS

Virological failure is defined by the non-suppression of virus levels at a prespecified follow-up time T(early virological failure), or by relapse. A binary virological failure endpoint is compared with three time-to-virological failure endpoints: time from (i) randomization that assigns early failures a failure time of T weeks; (ii) randomization that extends the early failure time T for slowly responding subjects; and (iii) virological response that assigns non-responders a failure time of 0 weeks. Endpoint differences are illustrated with Agouron's trial 511.

RESULTS

In comparing high with low-dose nelfinavir (NFV) regimens in Agouron 511, the difference in Kaplan-Meier estimates of the proportion not failing by 24 weeks is 16.7% (P = 0.048), 6.5% (P = 0.29) and 22.9% (P = 0.0030) for endpoints (i), (ii) and (iii), respectively. The results differ because NFV suppresses virus more quickly at the higher dose, and the endpoints weigh this treatment difference differently. This illustrates that careful consideration needs to be given to choosing a primary endpoint that will detect treatment differences of interest.

CONCLUSION

A time from randomization endpoint is usually recommended because of its advantages in flexibility and sample size, especially at interim analyses, and for its interpretation for patient management.

Toxicity and repellency of borate-sucrose water baits to Argentine ants (Hymenoptera: Formicidae)

The oral toxicity of boron compounds to the Argentine ant, Linepithema humile (Mayr), was evaluated in laboratory tests. The ants were provided 25% sucrose water containing 0.5 and 1% boric acid, disodium octaborate tetrahydrate, and borax. Lethal times of these solutions were a function of the concentration of boron. In field tests, the ants showed no discrimination between disodium octaborate tetrahydrate and boric acid. There was a significant reduction in consumption of sucrose water with > 1% boric acid.

Teaching prevention in pediatrics

Pediatrics has attempted to inculcate the "culture of prevention" into practice, both through anticipatory guidance in well-child care and through behavioral interventions in sick care. The effectivenesses of many components of well-child care have not been conclusively demonstrated, particularly in health education, counseling, and anticipatory guidance, nor has teaching prevention in pediatrics been thoroughly evaluated. This article reviews methods of teaching prevention in pediatrics and highlights innovative programs. Teaching programs use the wide range of approaches now common in medical education, in a variety of inpatient and outpatient sites. Programs across the country are trying new approaches to teaching traditional topics or are introducing new topics into their curricula. Examples of specific programs are given, organized by the themes of the programs. The field needs to develop in three major directions. First, there is a need to develop competencies and curricula in prevention issues of contemporary importance, including the new morbidities, cross-cultural issues, cost-effectiveness, quality of care, and practice in managed care and other community settings. Second, further work is needed to evaluate programs and measure educational outcomes. This feedback must in turn be used to redefine competencies, curricula, and programs, Third, there needs to be an accessible clearinghouse, and educational tools need to be disseminated. To be effective, a curriculum for prevention in pediatrics cannot stand alone, but must be part of a vertically and horizontally integrated curriculum. Further, creating horizontally and vertically integrated curricula in prevention teaching across disciplines should be the standard.

Argentine ant (Hymenoptera: Formicidae) trail pheromone enhances consumption of liquid sucrose solution

We investigated whether the Argentine ant, Linepithema humile (Mayr), trail pheromone, Z9-16:Ald, could enhance recruitment to and consumption of liquid sucrose solutions. All tests were done as paired comparisons with a 10% sucrose solution as food. In the laboratory, mixing 20 microl of a 10-microg/ml solution of the pheromone with 50 microl of the 10% sucrose solution increased the number of ants feeding by >150%. In a field test, we combined the trail pheromone with a 10% sucrose solution in 50-ml vials. These vials were covered with a plastic membrane that has 1.5-mm-diameter holes punched uniformly across its surface. Ants could drink from the holes after the vials were inverted. For half of the vials, 1 microg of the pheromone was put onto the plastic membrane before the vials were filled with a 10% sucrose solution. The remaining vials had no pheromone on the plastic membrane. After 4 h we measured the consumption in each vial. Bait consumption with the pheromone was enhanced by 29%. In a 2nd series of tests, vials were left outside for 24 h. The consumption rate was 33% higher with the pheromone compared with the controls that didn't have pheromone.