The Condor 86:443-l54 0 The Cooper Ornithological Society 1984 ALTITUDINAL VARIATIONS IN NESTS OF THE HAWAIIAN HONEYCREEPER HEMIGNATHUS VIRENS VIRENS

ABSTRACT. -We examined more than 90 nests of the Common Amakihi (Hemignathus virens virens) from the Island of Hawaii to determine if their placement, composition, or insulation varied with meteorological conditions at the time of nesting. Common Amakihi nest chiefly during the wet season. The nests were always within the canopy of the nest trees and consequently were probably shielded from rain. The nests from a warm rain forest on Kohala Mountain were significantly higher in the canopy and nearer each tree' s center than the nests from Mauna Kea, a cold upland Savannah. On Mauna Kea, nests were nearer the edge of the canopy at higher elevations, i.e., in a location where they would benefit from radiant solar energy. Nests from Kohala Mountain lacked liners and were more porous than those from Mauna Kea. These features permitted the nests to dry rapidly. Nests from Mauna Kea, in contrast, were always lined, which retarded drying and increased their insulating capacity-features appropriate for the drier, colder conditions in areas where they were built. All of the nests were excellent windscreens. The thermal conductance of nests from Mauna Kea diminished with altitude, i.e., nests at higher elevations had more insulation than those at lower elevations. This trend was associated with differences in the nests' walls, which were denser (but not thicker) at higher elevations. The nest' s thermal conductance can be used to estimate the energetic expense of incubation. For Common Amakihi, the energy required to keep a clutch at incubation temperature may be as much as 0.115 W or 47% of the birds' metabolic rate at rest. We speculated that the small size of the amakihi (13-l 4 g), coupled with the extreme variations in moisture and temperature to which populations are exposed while nesting, might have led to altitudinal differences in nest structure. For example, breeding success in rain forests might require a nest that will drain readily and dry quickly, but one that need not be highly insulated because of the mild and fairly constant temperatures in such habitats. In fact, amakihi on the Island of Kauai sometimes brace their nests against tree trunks where they are soaked by water running down the bark during heavy rains. In contrast, amakihi nesting at high elevations on the Island of Hawaii, where it is decidedly drier and colder, may require a more highly insulated nest, but one that is still capable of drying efficiently. Here, a nest with a liner might be more adaptive. In order to address these possibilities, we conducted qualitative and quantitative studies of m&e than 90 amakihi nests collected at many different elevations on the Island of Hawaii. MATERIALS AND METHODS STUDY SITES Most of our nests came from elevations between 1,600 and 2,600 m above sea level, around Puu Laau on the Island of Hawaii (2O"N, lSS.S' W). Puu Laau is on the southwestern or leeward slope of a dormant volcano, Mauna Kea, which rises 4,205 m above sea level. Since the mountain effectively blocks out the tradewinds, our study sites were in its rain shadow. The area is relatively dry and cold: rainfall is about 5 1 cm annually and temperatures frequently fall below 0°C in most months of the year; they rarely exceed 30°C (van Riper 1980). Puu Laau is one of the few remaining native dry forest ecosystems in Ha- [443

Characterisation of CD154+ T cells following ex vivo allergen stimulation illustrates distinct T cell responses to seasonal and perennial allergens in allergic and non-allergic individuals

Background Allergic sensitisation has been ascribed to a dysregulated relationship between allergen-specific Th1, Th2 and regulatory T cells. We sought to utilise our short-term CD154 detection method to further analyse the relationship between these T cell subsets and investigate differences between seasonal and perennial allergens. Using peripheral blood samples from grass-allergic, cat-allergic and healthy non-atopic subjects, we compared the frequencies and phenotype of CD154-positive T helper cells following stimulation with seasonal (grass) and perennial (cat dander) allergens. Results We identified a higher frequency of CD154+ T cells in grass-allergic individuals compared to healthy controls; this difference was not evident following stimulation with cat allergen. Activated Th1, Th2 and Tr1-like cells, that co-express IFNγ, IL4 and IL10, respectively, were identified in varying proportions in grass-allergic, cat-allergic and non-allergic individuals. We confirmed a close correlation between Th1, Th2 and Tr1-like cell frequency in non-allergic volunteers, such that the three parameters increased together to maintain a low Th2: Th1 ratio. This relationship was dysregulated in grass-allergic individuals with no correlation between the T cell subsets and a higher Th2: Th1 ratio. We confirmed previous reports of a late-differentiated T cell phenotype in response to seasonal allergens compared to early-differentiated T cell responses to perennial allergens. Conclusions The findings confirm our existing work illustrating an important balance between Th1, Th2 and Tr1-like responses to allergens in health, where Th2 responses are frequently observed, but balanced by Th1 and regulatory responses. We confirm previous tetramer-based reports of phenotypic differences in T cells responding to seasonal and perennial allergens

A review of seismic observations of Kepler and K2-Observed sdBV stars

This paper reviews recent seismic findings from Kepler and K2 data. Using three years of short cadence Kepler (K1) data, it is possible to examine time evolution of pulsations in an unprecedented way. While K2 observations are shorter, only three months, they are important as they are finding more sdBV stars than K1 did. Most importantly, K2 is discovering more p-mode pulsators with coverage not possible to get from the ground

Growth of (110) Diamond using pure Dicarbon

We use a density-functional based tight-binding method to study diamond growth steps by depositing dicarbon species onto a hydrogen-free diamond (110) surface. Subsequent C_2 molecules are deposited on an initially clean surface, in the vicinity of a growing adsorbate cluster, and finally, near vacancies just before completion of a full new monolayer. The preferred growth stages arise from C_2n clusters in near ideal lattice positions forming zigzag chains running along the [-110] direction parallel to the surface. The adsorption energies are consistently exothermic by 8--10 eV per C_2, depending on the size of the cluster. The deposition barriers for these processes are in the range of 0.0--0.6 eV. For deposition sites above C_2n clusters the adsorption energies are smaller by 3 eV, but diffusion to more stable positions is feasible. We also perform simulations of the diffusion of C_2 molecules on the surface in the vicinity of existing adsorbate clusters using an augmented Lagrangian penalty method. We find migration barriers in excess of 3 eV on the clean surface, and 0.6--1.0 eV on top of graphene-like adsorbates. The barrier heights and pathways indicate that the growth from gaseous dicarbons proceeds either by direct adsorption onto clean sites or after migration on top of the existing C_2n chains.Comment: 8 Pages, 7 figure