Organisms are expected to balance energy allocation in such a way that fitness is maximized. While much research has focussed on allocation strategies of reproducing parents, in particular birds, relatively little attention has been paid to how nestlings allocate energy while in the nest. Nestling birds are faced with a trade-off between devoting energy to growth or to thermoregulation, and in altricial species it is likely that the thermal environment of the nest site influences the nature of this trade-off. Here, we experimentally investigate how altering the microclimate of nests affects the growth, size and survival, as well as cell-mediated immune (CMI) response, of nestling tree swallows (Tachycineta bicolor) in a temperate environment. We place air-activated heating pads in nests of swallows when young were between 4 days and 16 days of age, and compared performance of offspring to control nests. Our manipulation raised temperatures of heated nests by approximately 5 degrees C compared to control nests. Offspring in heated nests had enhanced survival while in the nest, and we also found that they were heavier and had longer ninth primary feathers at 16 days of age. In addition, heating nest boxes resulted in significantly faster growth of primaries, and there was a trend for growth rates of mass to also be higher in heated nests. There were no significant differences between heated and control nests in growth rate or size of tarsus at age 16 days, and we speculate that this lack of response to elevated nest temperatures may be due to growth of skeletal structures being limited by other factors such as calcium availability. We also found no difference between heated and control nests in CMI response. Nonetheless, our results show overall that increasing temperatures of nests has significant benefits that enhance the fitness of offspring. As provisioning rates to offspring did not differ between heated and control nests, we suspect that the beneficial effects of heating were not the consequence of changes in parental behaviour. Our results provide insight into factors, other than food supply, that have important consequences in determining reproductive success of birds breeding in temperate environments.

We compared haematocrits and blood haemoglobin concentrations of nestling House Wrens Troglodytes aedon in nests with relatively large numbers of haematophagous larvae of the blow fly Protocalliphora parorum (>6.4 large larvae/nestling) and nests in which exposure to larvae was severely reduced or eliminated (0–2.0 larvae/nestling). Heavily parasitized nestlings showed no reduction in haematocrit levels but a significant 28% reduction in haemoglobin levels. Previous research on avian response to chronic blood loss suggests that parasitized nestlings may show normal volumes of red blood cells as a result of a rapid production of new cells in response to blood loss and, additionally, as a result of swelling of individual cells left in the bloodstream after parasite feeding. Rapid erythropoiesis places high numbers of haemoglobin‐poor, immature cells into the bloodstream which would explain the reduced haemoglobin levels of parasitized nestlings. Our results refute the conclusion that larval feeding has “little direct effect” on nestling wrens in this parasite–host system, drawn earlier by Johnson and Albrecht (1993) based on examination of haematocrits alone. Our results also strongly suggest that researchers wanting to measure effects of blood‐feeding parasites on birds measure haemoglobin levels, not haematocrits.

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Twenty-four novel 2,5-diaryl-1,3,4-oxadiazoline analogs of combretastatin A-4 (CA-4, 1) were designed, synthesized and evaluated for biological activities. The compounds represent two structural classes; the Type I class has three methoxy groups on the A ring and the Type II class has a single methoxy group on the A ring. Biological evaluations demonstrate that multiple structural features control the biological potency. Four of the compounds, 2-(3'-bromophenyl)-5-(3",4",5"-trimethoxyphenyl)-2-acetyl-2,3-dihydro-1,3,4-oxadiazoline (9l), 2-(2',5'-dimethoxyphenyl)-5-(3"-methoxyphenyl)-2-acetyl-2,3-dihydro-1,3,4-oxadiazoline (10h), 2-(3',4',5'-trimethoxyphenyl)-5-(3"-methoxyphenyl)-2-acetyl-2,3-dihydro-1,3,4-oxadiazoline (10i) and 2-(3',5'-dimethoxyphenyl)-5-(3"-methoxyphenyl)-2-acetyl-2,3-dihydro-1,3,4-oxadiazoline (10j), have potent antiproliferative activities against multiple cancer cell lines. Mechanistic studies indicate that they retain the microtubule disrupting effects of compound 1 including microtubule loss, the formation of aberrant mitotic spindles, and mitotic arrest. Compound 10i inhibits purified tubulin polymerization and circumvents drug resistance mediated by P-glycoprotein and βIII tubulin expression. The oxadiazoline analog 10i is a promising lead candidate worthy of further investigation.

Many species of birds line their nests with feathers, and it has been hypothesized that this functions to provide a thermally stable microenvironment for the development of eggs and nestlings. Feathers in the nest may also function as a mechanism for parasite control, providing a physical barrier that protects nestlings from ectoparasites. We tested these hypotheses by performing a feather removal and addition experiment in tree swallows Tachycineta bicolor, a species wellknown for lining their nests with feathers. While we found no evidence that quantity of feathers in nests influenced the ability of females to produce and incubate eggs, offspring in well-feathered nests had longer flight feathers and were structurally larger just prior to fledging that those in nests with fewer feathers. Furthermore, we also demonstrated a positive correlation between feathers and the abundance of larval blow flies Protocalliphora spp. in nests, a result opposite to that predicted by the anti-parasite hypothesis. While our study provides strong support for the insulation hypothesis, we also discuss the possibility that devoting time to feather gathering may result in males losing paternity in their nests, although manipulative studies will be necessary to fully evaluate this idea.

Re-establishing plant cover is essential for restoring ecosystem functions, but revegetation can be difficult in severe sites, such as salt marshes that experience hypersalinity and sedimentation. We tested three treatments (adding tidal creeks, planting seedlings in tight clusters, and rototilling kelp compost into the soil) in a site that was excavated to reinstate tidal flows and restore salt marsh. The magnitude of responses was the reverse of expectations, with tidal creeks having the least effect and kelp compost the most. On the marsh plain, kelp compost significantly increased soil organic matter (by 17% at 0-5 cm; p = 0.026 and 11.5% at 5-20 cm; p = 0.083), total Kjeldahl nitrogen (45% at 5-8 cm; p < 0.001) and inorganic nitrogen (35% at 5-8 cm; p < 0.006), and decreased bulk density (16% at 0-5 cm; p < 0.001 and 21% at 5-8 cm depth; p < 0.001) compared to control plots. Survivorship of kelp compost treated plantings increased, along with growth (>50% increase in a growth index at 20 months after planting; p < 0.0001). In Spartina foliosa plots, kelp compost did not affect soil organic matter, but plants were taller (by $11 cm; p = 0.003) and denser (47% more stems; p = 0.003). Planting seedlings 10-cm apart in tight clusters on the marsh plain increased survivorship by 18% (compared to 90-cm apart in loose clusters; p = 0.053), but not growth. Tidal creek networks increased survivorship of Batis maritima and Jaumea carnosa by ‡20% (p = 0.060 and 0.077, respectively). Kelp compost had a strong, positive influence on vegetation establishment by ameliorating some of the abiotic stress.

In this study we examined the nature of college-student depression and its relation to personality variables and to experiences unique to college life. Thirty-five depressed and 39 nondepressed students completed a depression inventory, a series of personality scales, and a survey developed to investigate the impact of potentially distressing components of college life. Results revealed that college-student depression, though mild in intensity, represents a serious problem: Three quarters of depressed students had been depressed for more than 3 months, and half had contemplated suicide. Both personality characteristics and experiential variables were found to be significantly related to depression, together accounting for approximately half the variance. We examined individual personality traits and experiential variables that were found to differ between depressed and nondepressed subjects, and we discuss the implications of the findings for counseling and for future research.Depression is considered to be the leading psychiatric disorder on college campuses (Beck & Young, 1978) and has been implicated as a precipitating factor in most suicides (Teuting, Koslow, & Hirschfeld, 1981), which are 50% more common among college students than among nonstudents of the same age (Beck & Young, 1978). Despite the gravity of the problem, however, very little research has been devoted to the investigation of depressed college students beyond their roles as analogues for depressed psychiatric patients. Thus, the present study sought to examine the nature of collegestudent depression. Personality characteristics and experiences unique to college life were investigated in relation to depression to provide both practitioners and researchers with a more in-depth and comprehensive understanding of this most serious problem.