Ammonia oxidizer populations vary with nitrogen cycling across a tropical montane mean annual temperature gradient.

Functional gene approaches have been used to better understand the roles of microbes in driving forest soil nitrogen (N) cycling rates and bioavailability. Ammonia oxidation is a rate limiting step in nitrification, and is a key area for understanding environmental constraints on N availability in forests. We studied how increasing temperature affects the role of ammonia oxidizing archaea (AOA) and bacteria (AOB) in soil N cycling and availability by using a highly constrained natural mean annual temperature (MAT) elevation gradient in a tropical montane wet forest. We found that net nitrate (NO3- ) bioavailability is positively related to MAT (r2  = 0.79, P = 0.0033), and AOA DNA abundance is positively related to both NO3- availability (r2  = 0.34, P = 0.0071) and MAT (r2  = 0.34, P < 0.001). In contrast, AOB DNA was only detected in some soils across the gradient. We identified three distinct phylotypes within the AOA which differed from one another in abundance and relative gene expression. In addition, one AOA phylotype increased in abundance with MAT, while others did not. We conclude that MAT is the primary driver of ecosystem N availability across this gradient, and AOA population size and structure appear to mediate the relationship between the nitrification and N bioavailability. These findings hold important implications for nutrient limitation in forests and feedbacks to primary production under changing climate.

Ethanol isotope method (EIM) for uncovering illegal wine.

Isotopic methods have proven to be a powerful analytical tool for the determination of origin and authenticity of wine. In addition, measuring the stable isotope ratio provides useful information for the detection of many illegal practices in the production of wine. The determinations of the stable isotope composition of compounds are based on measuring the relative ratios using isotope ratio mass spectrometry. This article describes a new isotopic method for measuring the δD value of non-exchangeable hydrogen stable isotopes in ethanol for investigating adulteration practices in wine making. With this new method, we are able to determine the addition of water and sugar in wine with higher accuracy, repeatability and reliability.

Temperature as a control over ecosystem CO2 fluxes in a high-elevation, subalpine forest.

We evaluated the hypothesis that CO(2) uptake by a subalpine, coniferous forest is limited by cool temperature during the growing season. Using the eddy covariance approach we conducted observations of net ecosystem CO(2) exchange (NEE) across two growing seasons. When pooled for the entire growing season during both years, light-saturated net ecosystem CO(2) exchange (NEE(sat)) exhibited a temperature optimum within the range 7-12 degrees C. Ecosystem respiration rate ( R(e)), calculated as the y-intercept of the NEE versus photosynthetic photon flux density (PPFD) relationship, increased with increasing temperature, causing a 15% reduction in net CO(2) uptake capacity for this ecosystem as temperatures increased from typical early season temperatures of 7 degrees C to typical mid-season temperatures of 18 degrees C. The ecosystem quantum yield and the ecosystem PPFD compensation point, which are measures of light-utilization efficiency, were highest during the cool temperatures of the early season, and decreased later in the season at higher temperatures. Branch-level measurements revealed that net photosynthesis in all three of the dominant conifer tree species exhibited a temperature optimum near 10 degrees C early in the season and 15 degrees C later in the season. Using path analysis, we statistically isolated temperature as a seasonal variable, and identified the dynamic role that temperature exhibits in controlling ecosystem fluxes early and late in the season. During the spring, an increase in temperature has a positive effect on NEE, because daytime temperatures progress from near freezing to near the photosynthetic temperature optimum, and R(e )values remain low. During the middle of the summer an increase in temperature has a negative effect on NEE, because inhibition of net photosynthesis and increases in R(e). When taken together, the results demonstrate that in this high-elevation forest ecosystem CO(2) uptake is not limited by cool-temperature constraints on photosynthetic processes during the growing-season, as suggested by some previous ecophysiological studies at the branch and needle levels. Rather, it is warm temperatures in the mid-summer, and their effect on ecosystem respiration, that cause the greatest reduction in the potential for forest carbon sequestration.

Leaf carbon isotope discrimination and nitrogen content for riparian trees along elevational transects.

Leaf carbon isotope discrimination (Δ), seasonal estimates of the leaf-to-air water vapor gradient on a molar basis (ω), and leaf nitrogen contents were examined in three riparian tree species (Populus fremontii, P. angustifolia, and Salix exigua) along elevational transects in northern and southern Utah USA (1500-2670 m and 600-1820 m elevational gradients, respectively). The ω values decreased with elevation for all species along transects. Plants growing at higher elevations exhibited lower Δ values than plants at lower elevations (P. fremontii, 22.9‰ and 19.5‰, respectively; P. angustifolia, 23.2‰ and 19.2‰, respectively; and S.␣exigua, 21.1‰ and 19.1‰, respectively). Leaf nitrogen content increased with elevation for all species, suggesting that photosynthetic capacity at a given intercellular carbon dioxide concentration was greater at higher elevations. Leaf Δ and nitrogen content values were highly correlated, implying that leaves with higher photosynthetic capacities also had lower intercellular carbon dioxide concentrations. No significant interannual differences were detected in carbon isotope discrimination.

Rugby football injuries, 1980-1983.

The injuries sustained by the boys at one English public school have been recorded and analysed by age, experience, position, phase, duration of the game and of the season. Few injuries have been serious. Detailed reference is made to concussion, injuries from collapsed scrums and injuries of the cervical spine. The paper emphasises that the tackle leads to most injuries. This paper presents the Rugby football injuries sustained by the boarders of Rugby School in the four seasons 1980-1983. The injury rate was 194 per 10,000 player hours, compared with the rate of 198 per 10,000 player hours for the thirty seasons 1950-1979 (Sparks, 1981). Tables I-VI list the injuries by different criteria. Table VII lists the sites of injury; Table VIII the time off Rugby football after injury; Table IX lists some of the more important injuries; Table XI summarises the playing results of the various school teams; Table XIII compares some of the Rugby School figures with those recorded in the Accident and Emergency Department of Christchurch Hospital during the 1979 New Zealand Rugby football season (Inglis and Stewart, 1981); Table XIV records information on three aspects of Rugby football that have occasioned much recent concern, viz:--Time off playing after concussion, injuries caused by collapsed scrums and neck injuries.

Mumps surveillance in England and Wales 1962-81.

A study of routine data on mumps in England and Wales suggests that its epidemiological features are changing from those of an epidemic disease in young adults and older children to a more endemic disease in younger children. Infection now occurs at an earlier age, at which complications are less frequent and symptomless infection may be more common. The incidence of clinical disease may be falling. The high proportion of registered deaths in the middle aged and elderly may be an artifact due to misclassification of causes of death and to misdiagnosis. These changes lessen the need for routine immunisation. Indeed with low acceptance rates of measles vaccination of 50% at age 15 months, mumps/measles routine vaccination at the same age is contraindicated because similarly low acceptance rates might lead to an increase in the number of cases of mumps in older children and young adults, at which ages complications are more frequent.

Half a million hours of rugby football. The injuries.

In 30 seasons at Rugby School half a million hours of Rugby football have led to 9,885 injuries, an incidence of 197.7 injuries per 10.000 player hours. This incidence is compared with those from other school games, and with those of other series of Rugby football injuries. The injuries are compared regionally with those of other series, and the more important are listed.