Association between haematozoan infections and reproduction in the Pied Flycatcher

1. Parasites may affect breeding success of their host since they compete for the same resources as their hosts. Reproduction may also increase the susceptibility of a host to parasite infections owing to lowered resistance to parasites during breeding.
2. We studied the association between breeding performance and haematozoan parasite infection in the Pied Flycatcher ( Ficedula hypoleuca ) by using both natural data on reproduction and data from clutch size manipulations.
3. The most frequent blood parasites of the Pied Flycatcher in central Finland were Haemoproteus pallidus , Haemoproteus balmorali and Trypanosoma avium complex.
4. We did not find evidence that these haematozoan parasites have any debilitating effects on either reproduction or survival. The variation in reproductive effort did not seem to influence susceptibility to new blood parasite infections.
5. The intensity of Haemoproteus balmorali tended to increase in infected males as the brood size was artificially enlarged. Also, in females intensity of H. pallidus infection tended to increase with the level of clutch size manipulation. Thus, increased reproductive effort seems to debilitate the ability of Pied Flycatcher to control chronic infections.
6. Individuals with enlarged clutches/broods increased their reproductive effort at the expense of defence towards parasites. The cost of current reproduction may then be at least partly mediated by haematozoan infections.     

Effects of elevated O3 and CO2 concentrations on photosynthesis and stomatal conductance in Scots pine

Naturally regenerated Scots pines (Pinus sylvestris L.), aged 28–30 years old, were grown in open-top chambers and subjected in situ to three ozone (O₃) regimes, two concentrations of CO₂, and a combination of O₃ and CO₂ treatments From 15 April to 15 September for two growing seasons (1994 and 1995). The gas exchanges of current-year and 1-year-old shoots were measured, along with the nitrogen content of needles. In order to investigate the factors underlying modifications in photosynthesis, five parameters linked to photosynthetic performance and three to stomatal conductance were determined. Elevated O₃ concentrations led to a significant decline in the CO₂ compensation point (Г^*), maximum RuP₂-saturated rate of carboxylation (V_cmax), maximum rate of electron transport (J_max), maximum stomatal conductance (g_smax), and sensitivity of stomatal conductance to changes in leaf-to-air vapour pressure difference (?g_s/?D_v) in both shoot-age classes. However, the effect of elevated O₃ concentrations on the respiration rate in light (R_d) was dependent on shoot age. Elevated CO₂(700 μmol mol^?1) significantly decreased J_max and g_smax but increased R_d in 1-year-old shoots and the ?g_s/?D_v in both shoot-age classes. The interactive effects of O₃ and CO₂ on some key parameters (e.g. V_cmax and J_max) were significant. This may be closely related to regulation of the maximum stomatal conductance and stomatal sensitivity induced by elevated CO₂. As a consequence, the injury induced by O₃ was reduced through decreased ozone uptake in 1-year-old shoots, but not in the current-year shoots. Compared to ambient O₃ concentration, reduced O₃ concentrations (charcoal-filtered air) did not lead to significant changes in any of the measured parameters. Compared to the control treatment, calculations showed that elevated O₃ concentrations decreased the apparent quantum yield by 15% and by 18%, and the maximum rate of photosynthesis by 21% and by 29% in the current-year and 1-year-old shoots, respectively. Changes in the nitrogen content of needles resulting from the various treatments were associated with modifications in photosynthetic components.     

LIKING FOR ICE CREAM MEASURED WITH THREE PROCEDURES: SIDE-BY-SIDE, AFTER CONSUMPTION AND SINGLE SAMPLES

The purpose of this study was to compare how similar results are achieved by three different procedures of measuring liking for ice cream. Subjects (N=56) assessed their liking for three brands of vanilla ice cream on a 9-point scale in seven sessions within three weeks. The examined procedures were (1) tasting and rating all three brands simultaneously side-by-side within the same session, (2) rating each brand in separate sessions after ad libitum consumption and (3) tasting (without consumption) and rating each brand in separate sessions. The liking scores for brands differed significantly but the differences were small because all samples were well-liked. In all procedures, the ratings of liking differed clearly between those who ranked the brand first and those who ranked it second or third, even if there was a considerable number of tied first places. Correlations among the three different measurements of liking were relatively low for all brands of ice cream (r = 0.16 – 0.37). The most preferred brand for most respondents changed from one procedure to another. The perceived characteristics were close to ideal in all brands, and all three procedures gave similar mean results. The distance of mouthfeel, creaminess, sweetness, and vanilla aroma from ideal differed between those who liked the brand best and those who rated it second or third. These differences were larger in side-by-side and after consumption conditions compared to single sample presentation.     

Night,day, sunrise,sunset: do fish under snow and ice recognize the difference?

1. Although boreal lakes are ice‐covered for several months annually, little is known about the behaviour of fish under ice. To consider the reasons for diel vertical migrations (DVM) it is important to compare periods under ice as opposed to under open water. Echosounding provides a tool for non‐intrusive continuous monitoring of fish, even in winter. 2. Changes in the vertical distribution of fish through six 48‐h periods were monitored using a stationary, mounted echosounder that beamed vertically either from the bottom up or from the surface down from February to April, 2003. The up‐beaming and down‐beaming transducers were run alternately for 24 h each over the 48‐h period. Standard echo analysis software was used to detect fish traces and estimate the vertical and temporal distribution of fish abundance. Fish were sampled with a winter seine. 3. Prominent diel vertical migration in response to changing light level was detected throughout the study period (late winter to spring). Fish were highest in the water column at sunset and sunrise. In daylight, most detected fish were well below 10‐m depth. The number of fish detected was greatest during the night when they occurred throughout almost the whole water column, sometimes with a considerable number very close to the ice. Fish were mostly vendace and whitefish. 4. It became evident from data from the up‐beaming transducer that at night fish may occupy the layer closest to the surface. These fish would not have been detected if we had only used the down‐beaming transducer. The overall pattern of DVM in winter was very similar to that in summer. The results support the suggestion that DVM is a genetically fixed behavioural trait responding to the contemporary level of illumination.     

X-linked megalocornea caused by mutations in CHRDL1 identifies an essential role for ventroptin in anterior segment development

X-linked megalocornea (MGC1) is an ocular anterior segment disorder characterized by an increased cornea diameter and deep anterior chamber evident at birth and later onset of mosaic corneal degeneration (shagreen), arcus juvenilis, and presenile cataracts. We identified copy-number variation, frameshift, missense, splice-site and nonsense mutations in the Chordin-like 1 gene (CHRDL1) on Xq23 as the cause of the condition in seven MGC1 families. CHRDL1 encodes ventroptin, a bone morphogenic protein antagonist with a proposed role in specification of topographic retinotectal projections. Electrophysiological evaluation revealed mild generalized cone system dysfunction and, in one patient, an interhemispheric asymmetry in visual evoked potentials. We show that CHRDL1 is expressed in the developing human cornea and anterior segment in addition to the retina. We explored the impact of loss of ventroptin function on brain function and morphology in vivo. CHRDL1 is differentially expressed in the human fetal brain, and there is high expression in cerebellum and neocortex. We show that MGC1 patients have a superior cognitive ability despite a striking focal loss of myelination of white matter. Our findings reveal an unexpected requirement for ventroptin during anterior segment development and the consequences of a lack of function in the retina and brain.     

Atmospheric impact of bioenergy based on perennial crop (reed canary grass,Phalaris arundinaceae,L.) cultivation on a drained boreal organic soil

Marginal organic soils, abundant in the boreal region, are being increasingly used for bioenergy crop cultivation. Using long‐term field experimental data on greenhouse gas (GHG) balance from a perennial bioenergy crop [reed canary grass (RCG), Phalaris arundinaceae L.] cultivated on a drained organic soil as an example, we show here for the first time that, with a proper cultivation and land‐use practice, environmentally sound bioenergy production is possible on these problematic soil types. We performed a life cycle assessment (LCA) for RCG on this organic soil. We found that, on an average, this system produces 40% less CO₂‐equivalents per MWh of energy in comparison with a conventional energy source such as coal. Climatic conditions regulating the RCG carbon exchange processes have a high impact on the benefits from this bioenergy production system. Under appropriate hydrological conditions, this system can even be carbon‐negative. An LCA sensitivity analysis revealed that net ecosystem CO₂ exchange and crop yield are the major LCA components, while non‐CO₂ GHG emissions and costs associated with crop production are the minor ones. Net bioenergy GHG emissions resulting from restricted net CO₂ uptake and low crop yields, due to climatic and moisture stress during dry years, were comparable with coal emissions. However, net bioenergy emissions during wet years with high net uptake and crop yield were only a third of the coal emissions. As long‐term experimental data on GHG balance of bioenergy production are scarce, scientific data stemming from field experiments are needed in shaping renewable energy source policies.