Underwater visibility constrains the foraging behaviour of a diving pelagic seabird.

Understanding the sensory ecology of species is vital if we are to predict how they will function in a changing environment. Visual cues are fundamentally important for many predators when detecting and capturing prey. However, many marine areas have become more turbid through processes influenced by climate change, potentially affecting the ability of marine predators to detect prey. We performed the first study that directly relates a pelagic seabird species's foraging behaviour to oceanic turbidity. We collected biologging data from 79 foraging trips and 5472 dives of a visually dependent, pursuit-diving seabird, the Manx shearwater (Puffinus puffinus). Foraging behaviour was modelled against environmental variables affecting underwater visibility, including water turbidity, cloud cover and solar angle. Shearwaters were more likely to initiate area-restricted search and foraging dives in clearer waters. Underwater visibility also strongly predicted dive rate and depth, suggesting that fine-scale prey capture was constrained by the detectability of prey underwater. Our novel use of dynamic descriptors of underwater visibility suggests that visual cues are vital for underwater foraging. Our data indicate that climate change could negatively impact seabird populations by making prey more difficult to detect, compounded by the widely reported effects of reduced prey populations.

A high-density SNP chip for genotyping great tit (Parus major) populations and its application to studying the genetic architecture of exploration behaviour.

High-density SNP microarrays ("SNP chips") are a rapid, accurate and efficient method for genotyping several hundred thousand polymorphisms in large numbers of individuals. While SNP chips are routinely used in human genetics and in animal and plant breeding, they are less widely used in evolutionary and ecological research. In this article, we describe the development and application of a high-density Affymetrix Axiom chip with around 500,000 SNPs, designed to perform genomics studies of great tit (Parus major) populations. We demonstrate that the per-SNP genotype error rate is well below 1% and that the chip can also be used to identify structural or copy number variation. The chip is used to explore the genetic architecture of exploration behaviour (EB), a personality trait that has been widely studied in great tits and other species. No SNPs reached genomewide significance, including at DRD4, a candidate gene. However, EB is heritable and appears to have a polygenic architecture. Researchers developing similar SNP chips may note: (i) SNPs previously typed on alternative platforms are more likely to be converted to working assays; (ii) detecting SNPs by more than one pipeline, and in independent data sets, ensures a high proportion of working assays; (iii) allele frequency ascertainment bias is minimized by performing SNP discovery in individuals from multiple populations; and (iv) samples with the lowest call rates tend to also have the greatest genotyping error rates.

Personality predicts individual responsiveness to the risks of starvation and predation.

Theory suggests that individual personality is tightly linked to individual life histories and to environmental variation. The reactive-proactive axis, for example, is thought to reflect whether individuals prioritize productivity or survival, mutually exclusive options that can be caused by conflicts between foraging and anti-predation behaviour. Evidence for this trade-off hypothesis, however, is limited. Here, we tested experimentally whether exploration behaviour (EB), an assay of proactivity, could explain how great tits (Parus major) respond to changes in starvation and predation risk. Individuals were presented with two feeders, holding good or poor quality food, which interchanged between safe and dangerous positions 10 m apart, across two 24 h treatments. Starvation risk was assumed to be highest in the morning and lowest in the afternoon. The proportion of time spent feeding on good quality food (PTG) rather than poor quality food was repeatable within treatments, but individuals varied in how PTG changed with respect to predation- and starvation-risk across treatments. This individual plasticity variation in foraging behaviour was linked to EB, as predicted by the reactive-proactive axis, but only among individuals in dominant social classes. Our results support the trade-off hypothesis at the level of individuals in a wild population, and suggest that fine-scale temporal and spatial variation may play important roles in the evolution of personality.

Data depth, data completeness, and their influence on quantitative genetic estimation in two contrasting bird populations.

Evolutionary biologists increasingly use pedigree-based quantitative genetic methods to address questions about the evolutionary dynamics of traits in wild populations. In many cases, phenotypic data may have been collected only for recent parts of the study. How does this influence the performance of the models used to analyse these data? Here we explore how data depth (number of years) and completeness (number of observations) influence estimates of genetic variance and covariance within the context of an existing pedigree. Using long-term data from the great tit Parus major and the mute swan Cygnus olor, species with different life-histories, we examined the effect of manipulating the amount of data included on quantitative genetic parameter estimates. Manipulating data depth and completeness had little influence on estimated genetic variances, heritabilities, or genetic correlations, but (as expected) did influence confidence in these estimates. Estimated breeding values in the great tit were not influenced by data depth but were in the mute swan, probably because of differences in pedigree structure. Our analyses suggest the 'rule of thumb' that data from 3 years and a minimum of 100 individuals per year are needed to estimate genetic parameters with acceptable confidence, and that using pedigree data is worthwhile, even if phenotypes are only available toward the tips of the pedigree.

Effect of serotonin depletion on 5-HT2A-mediated learning in the rabbit: evidence for constitutive activity of the 5-HT2A receptor in vivo.

RATIONALE: Associative learning during Pavlovian eyeblink conditioning has been shown to be regulated by 5-HT2A receptors. The existence of inverse agonists that retard learning through an action at the 5-HT2A receptor suggests the existence of constitutive activity at that receptor and that depletion of serotonin should have minimal effects on learning. OBJECTIVES: We examined whether depletion of serotonin would impair trace eyeblink conditioning or the enhancement of conditioning produced by the agonist lysergic acid diethylamide (LSD) and the retardation of conditioning produced by the inverse agonist MDL11,939. METHODS: Animals received bilateral intraventricular injections of 5,7-dihydroxytryptamine (5,7-DHT) at doses of 760 or 1,140 microg/side (1.88 or 2.82 micromol/side) and were later exposed to eight daily conditioning sessions. RESULTS: Serotonin depletion produced by the lower dose of 5,7-DHT was 71 and 72% in cortex and hippocampus, respectively, with no change in 5-HT2A receptor density, no effect on learning, and no effect on the ability of LSD to enhance and MDL11,939 to retard learning. The higher dose of 5,7-DHT produced serotonin decreases of 85 and 90% in cortex and hippocampus, respectively, accompanied by a 96% decrease in the density of the serotonin transporter, but no significant effect on learning. CONCLUSIONS: Pavlovian trace eyeblink conditioning is regulated predominantly by the constitutive activity of the 5-HT2A receptor rather than by serotonin release onto the receptor during learning. It was suggested that the 5-HT2A receptor regulates learning by modulating the release of dopamine, acetylcholine, and glutamate, transmitters known to affect eyeblink conditioning.

Good foragers can also be good at detecting predators.

The degree to which foraging and vigilance are mutually exclusive is crucial to understanding the management of the predation and starvation risk trade-off in animals. We tested whether wild-caught captive chaffinches that feed at a higher rate do so at the expense of their speed in responding to a model sparrowhawk flying nearby, and whether consistently good foragers will therefore tend to respond more slowly on average. First, we confirmed that the time taken to respond to the approaching predator depended on the rate of scanning: as head-up rate increased so chaffinches responded more quickly. However, against predictions, as peck rate increased so head-up rate increased and mean length of head-up and head-down periods decreased. Head-up rate was probably dependent on peck rate because almost every time a seed was found, a bird raised its head to handle it. Therefore chaffinches with higher peck rates responded more quickly. Individual chaffinches showed consistent durations of both their head-down and head-up periods and, therefore, individuals that were good foragers were also good detectors of predators. In relation to the broad range of species that have a similar foraging mode to chaffinches, our results have two major implications for predation/starvation risk trade-offs: (i) feeding rate can determine vigilance scanning patterns; and (ii) the best foragers can also be the best at detecting predators. We discuss how our results can be explained in mechanistic terms relating to fundamental differences in how the probabilities of detecting food rather than a predator are affected by time. In addition, our results offer a plausible explanation for the widely observed effect that vigilance continues to decline with group size even when there is no further benefit to reducing vigilance.

Physician collective bargaining: all eyes are on Texas.

In June of 1999, Texas became the first state to pass a law allowing physicians to collectively bargain with managed care plans for fee-related activities. Whether this law will give physicians renewed control over patient care remains to be seen. Notwithstanding the intention of its drafters, it is likely that the law and its proposed regulations may only provide physicians with costly and time-consuming procedures that present multiple risks instead of renewed power.

Germline brca2 sequence variants in patients with ocular melanoma.

On the basis, chiefly, of anecdotal reports of cases of ocular melanoma (OM) occurring in families with inherited susceptibility to breast cancer due to brca2 germline mutations, we examined the frequency of brca2 alterations in a series of 62 ocular melanoma cases. These cases were preferentially selected on the basis of reported family history of breast or ovarian cancer, or OM, although the series also included a randomly selected set of cases without family history of cancer. A total of 7 germline alterations were found, of which 3 were likely to be associated with disease. While all 3 deleterious mutations were found in patients who also had a personal history of breast cancer, only 1 of the 3 families had a family history of breast/ovarian cancer or OM. Although germline brca2 mutations may account for a small proportion of all OM cases, there may be additional loci that contribute to familial aggregation of OM and to the familial association between OM and breast cancer.

Childbearing history associated with improved survival in choroidal melanoma.

BACKGROUND: Research in cutaneous melanoma suggests that women may experience better tumor-dependent survival than men, and some studies have shown that the advantage is specific to childbearing. OBJECTIVE: To examine whether childbearing may be a favorable prognostic factor in melanoma of the uveal tract. DESIGN: Prospective follow-up study. SETTING: Hospital. MAIN OUTCOME MEASURE: Death from metastatic choroidal melanoma. METHODS: We evaluated a consecutive series of 1818 patients with choroidal melanoma, 748 parous and 165 nulliparous women and 905 men, after treatment with proton irradiation. Three hundred fifty-two deaths from metastasis were documented in follow-up. RESULTS: Overall multivariate-adjusted death rates from metastasis were approximately 25% higher in nulliparous women (relative risk [RR], 1.23; 95% confidence interval [CI], 0.83-1.82) and men (RR, 1.25; 95% CI, 1.00-1.56) than in women who had given birth. The protective influence of parity was strongest in the early period following diagnosis and treatment (RR, 1.58; 95% CI, 0.88-2.86, and RR, 1.51; 95% CI, 1.04-2.19, in nulliparous women and men, respectively, during the first 36 months of follow-up). The level of protection increased with the number of live births (P for trend, .04). CONCLUSION: These data provide support for the hypothesis that a history of childbearing confers protection from death in choroidal melanoma.

Community care management across the continuum. Study results from a Medicare health maintenance plan.

A large national health plan piloting a community care management (CCM) model for its high-risk, chronically ill, Medicare population has demonstrated a significant reduction in overall medical costs for its participants. The key elements include: the proactive identification and risk stratification of members; assignment of advanced practice nurses to physicians with high-volume high-risk members; and ongoing clinical management across the continuum, establishing a continuous relationship with the member. The results are derived from a retrospective study comparing 6 months of claim data prior to the member entering CCM, with 6 months of claim data while participants received community, care management. Members in the pilot study experienced both a 42% reduction in institutional days and a 53% reduction in admissions to acute care settings. In addition, physician and specialists fees were reduced by 37%. This resulted in a 6-month net savings of $3,602 per participant. To be extremely conservative, the savings were reduced by 50% to reflect the possible impact of regression to the mean. Even accounting for this, the program's projected cost savings are $1,801 per participant in 6 months. The total projected savings for community care managed members in a fully implemented program divided by the entire enrolled population of 27,000 is $6.60 per member per month (PM/PM). The results of this study of care management across the continuum signal a new approach for medical management at a time when health care and the needs of the population are changing.

Worksite wellness programs and lifestyle behaviors.

Do employees who participate in worksite wellness programs differ from those who do not? What health-related lifestyle behaviors are practiced most frequently by which employees? A descriptive, correlational, comparative design was used to investigate these questions. Four hundred employees at a large public university were selected through stratified random sampling to complete a demographic sheet and the Health Promoting Lifestyle Profile (HPLP). Study findings revealed that men used self-actualization and exercise behaviors more frequently than women. Women practiced more health responsibility behaviors than men. Employees who were members of the wellness program more frequently practiced health responsibility and exercise behaviors than nonmembers. Overall, wellness program members used a greater number of the total health-related behaviors than other employees. Membership in the wellness program and the number of times per week a person exercised explained 21% of the variance in the HPLP scores.

Histogenesis of vascular tumors in the Proteus syndrome.

Proteus syndrome (PS) is a congenital disorder manifesting with severe deformities, the salient features being gigantism and vascular tumors. The disorder is poorly understood, and there has been much discrepancy in the terminology regarding the vascular tumors in PS. The purpose of this study was to elucidate the histogenesis of these tumors by correlating microscopic observations with immunohistologic information. The value of immunoperoxidase studies in the pathologic evaluation of PS was also assessed. Fourteen formalin-fixed, paraffin-embedded tissue specimens obtained from vascular tumors of six children with PS were stained with Ulex europaeus agglutinin I (UEA-I) lectin and the following immunohistochemical reagents: anti-factor VIII-related antigen (FVIII-RAg) and anti-CD34. The tumors showed varied proportions of vascular, lipomatous, and fibrous tissue components consistent with vascular hamartomas. The predominant vascular channels of the tumors were morphologically consistent with lymphatic vessels. Immunostaining of the endothelium of these vessels was most consistently positive with UEA-I lectin. Although a color reaction product was present in small vessels and some larger blood vessels, anti-CD34 immunostaining spared the lumens of lymphatic channels. In addition, a striking population of dendritic spindle cells was noted with the anti-CD34 but was unnoticed with the other reagents. We concluded that the vascular tumors of PS are primarily lymphatic hamartomas. The spindle cells noted with anti-CD34 immunostaining may relate to angiogenesis and need further delineation.

Granular cell tumor of the biliary tree. A report of two cases and a review of the literature.

Granular cell tumors are relatively uncommon soft tissue tumors usually presenting in the skin and subcutaneous tissues or tongue, although many sites have been described. Two cases arising in the extrahepatic biliary tree are described, and the previously reported cases of this rare presentation are reviewed. These tumors may mimic sclerosing cholangitis and cholangiocarcinoma clinically, and occasionally histologically, in this relatively young group of patients. The histogenesis appears to be related to Schwann cells as in granular cell tumors of other sites, evidenced by histologic, immunohistochemical, and electron microscopic findings. Granular cell tumors, albeit rare, should be considered in the differential diagnosis of biliary tract disease in young patients, particularly black women, and are curable by surgical excision.

Diagnosis of Pneumocystis carinii pneumonia by induced sputum in a city with moderate incidence of AIDS.

Examination of induced sputum from AIDS patients has been reported to provide the noninvasive diagnosis of PCP in 10 to 76 percent of cases. Since previous studies were done in centers with a high incidence of AIDS, we asked whether this test could be implemented successfully in a center with a lower incidence of AIDS. Over a 13-month period 25 of 38 (66 percent) AIDS patients with PCP had positive Giemsa (Diff-Quik) stains of induced sputum. We were unable to predict before sputum induction which patients would be positive based on clinical severity (increased A-a gradient or serum LDH levels). We confirmed prior observations that a normal serum LDH level was found in only 5 percent of documented PCP cases. This noninvasive technique significantly decreased the number of bronchoscopies performed and led to a considerable cost savings.