Biomass allocation and canopy development in spruce model ecosystems under elevated CO2 and increased N deposition

Ecosystem-level experiments on the effects of atmospheric CO₂ enrichment and N deposition on forest trees are urgently needed. Here we present data for nine model ecosystems of spruce (Picea abies) on natural nutrient-poor montane forest soil (0.7 m² of ground and 350 kg weight). Each system was composed of six 7-year-old (at harvest) trees each representing a different genotype, and a herbaceous understory layer (three species). The model ecosystems were exposed to three different CO₂ concentrations (280, 420, 560 μl l⁻¹) and three different rates of wet N deposition (0, 30, 90 kg ha⁻¹ year⁻¹) in a simulated annual course of Swiss montane climate for 3 years. The total ecosystem biomass was not affected by CO₂ concentration, but increased with increasing N deposition. However, biomass allocation to roots increased with increasing CO₂ leading to significantly lower leaf mass ratios (LMRs) and leaf area ratios (LARs) in trees grown at elevated CO₂. In contrast to CO₂ enrichment, N deposition increased biomass allocation to the aboveground plant parts, and thus LMR and LAR were higher with increasing N deposition. We observed no CO₂ ×  N interactions on growth, biomass production, or allocation, and there were also no genotype × treatment interactions. The final leaf area index (LAI) of the spruce canopies was 19% smaller at 420 and 27% smaller at 560 than that measured at 280 μl CO₂ l⁻¹, but was not significantly altered by increasing N deposition. Lower LAIs at elevated CO₂ largely resulted from shorter branches (less needles per individual tree) and partially from increased needle litterfall. Independently of N deposition, total aboveground N content in the spruce communities declined with increasing CO₂ (−18% at 420 and −31% at 560 compared to 280 μl CO₂ l⁻¹). N deposition had the opposite effect on total above ground N content (+18% at 30 and +52% at 90 compared to 0 kg N ha⁻¹ year⁻¹). Our results suggest that under competitive conditions on natural forest soil, atmospheric CO₂ enrichment may not lead to higher ecosystem biomass production, but N deposition is likely to do so. The reduction in LAI under elevated CO₂ suggests allometric down-regulation of photosynthetic carbon uptake at the canopy level. The strong decline in the tree nitrogen mass per unit ground area in response to elevated CO₂ may indicate CO₂-induced reductions of soil N availability. Received: 11 May 1997 / Accepted: 4 August 1997     

Association between VDR ApaI Polymorphism and Hip Bone Mineral Density Can Be Modified by Body Mass Index： A Study on Postmenopausal Chinese Women

Osteoporosis is a major public health problem for old people. Genetic factors are considered to be major contributors to the pathogenesis of postmenopausal osteoporosis. The vitamin D receptor (VDR) gene is a prominent candidate gene for the regulation of postmenopausal bone mass; however, despite extensive studies, controversy remains regarding its association with postmenopausal body mineral density (BMD) variation. In this study, a total of 260 healthy postmenopausal Chinese women were genotyped at the VDR ApaI locus using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Raw hip BMD was significantly associated with VDR ApaI polymorphism with and without adjusting for age (P=0.015 and 0.040, respectively). This genetic effect can explain 3.32% of hip BMD variation. However, the significant association vanished after correcting for both age and body mass index (BMI) (P=0.169). In addition, we observed a significant association between VDR ApaI polymorphism with unadjusted BMI(P=0.042) or BMI adjusted for age (P=0.049). The raw hip BMD was also found to be significantly correlated with BMI (r=0.517, P=0.0001), with BMI explaining 26.35% of the variation of hip BMD. All of these facts prompt us to conclude that the significant association between the VDR ApaI genotype and hip BMD may be modified by BMI in postmenopausal Chinese women. Our findings may partially explain the earlier inconsistent association results concerning the VDR gene and BMD, and highlight the importance of incorporating covariates such as BMI into osteoporosis association studies.     

An empirical assessment of human development through remote sensing: Evidences from Italy

The Human Development Index (HDI) based on life expectancy, education and per-capita income, is one of the most used indicators of human development. However, undeniable problems in data collection limit between-countries comparisons reducing the practical applicability of the HDI in official statistics. Elvidge et al. (2012) proposed an alternative index of human development (the so called Night Light Development Index, NLDI) derived from nighttime satellite imagery and population density, with improved comparability over time and space. The NLDI assesses inequality in the spatial distribution of night light among resident inhabitants and has proven to correlate with the HDI at the country scale. However, the NLDI presents some drawbacks, since similar NLDI values may indicate very different levels of human development. A modified NLDI overcoming such a drawback is proposed and applied to assessment of human development at 3 spatial scales (the entire country, 5 geographical divisions and 20 administrative regions) in Italy, a country with relevant territorial disparities in various socioeconomic dimensions. The original and modified NLDI were correlated with 5 independent indicators of economic growth, sustainable development and environmental quality. The spatial distribution of the original and modified NLDI is not coherent with the level of human development in Italy being indeed associated with various indexes of environmental quality. Further investigation is required to identify in which socioeconomic context (and at which spatial scale) the NDLI approach correctly estimates the level of human development in affluent countries.     

Challenges in calculation of the gamma index in radiotherapy – Towards good practice

The gamma index (γ) is one of the most commonly used metrics for the verification of complex modulated radiotherapy. The mathematical definition of the γ is computationally expensive and various techniques have been reported to speed up the calculation either by mathematically refining the γ or employing various computational techniques. These techniques can cause variation in output with different software implementations. The γ has traditionally been used to compare a 2D measured plane against a 2D or 3D dose distribution. Recently, software algorithm and hardware improvements have led to the possibility of using measured 2D data from commercial detector arrays to reconstruct a 3D-dose distribution and perform a volumetric comparison against the treatment planning system (TPS). A limitation in this approach is that commercial detector arrays have so far been limited by their spatial resolution which may affect the accuracy of the reconstructed 3D volume and subsequently the γ calculation. Additionally, 3D versus 3D γ comparison adds a layer of complication in the calculation of the γ given the increase in the number of calculation points and the result cannot be as easily interpreted in the same way as 2D comparison. This review summarises and highlights the computational challenges of the γ calculation and sheds light on some of these issues by means of a bespoke MATLAB software to demonstrate the impact of interpolation, γ search distance, resolution and 2D and 3D calculations. Finally, a recommendation is made on the minimum information that should be reported when publishing γ results.     

Testes investment and spawning mode in pipefishes and seahorses (Syngnathidae)

Externally fertilizing fishes are predicted to invest heavily in testes, because large numbers of sperm should be favoured by the high risk of sperm competition from sneaker males, and/or the dilution of ejaculates when shed into open water. Using museum specimens, we measured testes mass and body mass of 83 mature males, belonging to 21 genera of the family Syngnathidae (pipefishes and seahorses). In this family all species show paternal care, ranging in degree from eggs being attached to the skin of the male, to eggs being completely enclosed and nurtured within a brood pouch. The former, 'unprotected' group, is thought to have external fertilization, whereas in the latter, 'protected' group, males fertilize the eggs internally in their brood pouch. Smaller relative testes investment was thus predicted for genera that have protected compared with unprotected brood care. However, we found this not to be the case. Instead, all genera showed the same relationship between testes and body mass, regardless of brooding type. The possible implications of this surprising result are discussed, including the possibility that the mode of fertilization might have been misjudged for the pouchless syngnathids.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 369–376.     

Sensitivity of volatile monoterpene emission to changes in canopy structure: a model-based exercise with a process-based emission model

This paper investigates the dependence of monoterpene emissions at the canopy scale on total leaf area and leaf distribution. Simulations were carried out for a range of hypothetical but realistic forest canopies of the evergreen Quercus ilex (holm oak). Two emission models were applied that either did (SIM-BIM2) or did not (G93) account for cumulative responses to temperature and light. Both were embedded into a canopy model that considered spatial and temporal variations of foliage properties. This canopy model was coupled to a canopy climate model (CANOAK) to determine the micrometeorological conditions at the leaf scale. Structural properties considerably impacted monoterpene emission. The sensitivities to changes in total leaf area and to leaf area distribution were found to be of similar magnitude. The two different models performed similarly on a whole-year basis but showed clear differences during certain episodes. The analysis showed that structural indices have to be carefully evaluated for proper scaling of emission from leaves to canopy. Further research is encouraged on seasonal dynamics of emission potentials.     

Beyond HDL-cholesterol increase: phospholipid enrichment and shift from HDL3 to HDL2 in alcohol consumers

The reduction of cardiovascular mortality associated with moderate alcohol consumption is chiefly thought to be mediated by an increase of high density lipoprotein cholesterol (HDL-CH). This study highlights additional qualitative changes of HDL that might augment this antiatherogenic effect. In 279 healthy men, alcohol and nutrient consumption were evaluated. Groups 1 (n=62), 2 (n=172), and 3 (n=45) comprised subjects with alcohol consumption of 0-5.0, 5.1-30.0, and 30.1-75 g/day, respectively. Lipid analysis was performed in nonfractionated and fractionated plasma, including subfractions HDL(2a), HDL(2b), and HDL(3). No difference in LDL-cholesterol was observed. Compared with group 1, groups 2 and 3 exhibited significant increases of HDL-CH (group 1, 44 +/- 10 mg/dl; group 2, 51 +/- 11 mg/dl; group 3, 55 +/- 11 mg/dl; mean +/- SD, P<0.0005), accompanied by enhanced lipidation of HDL (increase of the HDL(2)-CH/HDL(3)-CH ratio). Moreover, phospholipid enrichment of HDL occurred in alcohol consumers, whereas the ratios between other HDL components remained constant. Multivariate analysis revealed alcohol to have the foremost statistical influence on changes of the HDL fraction, followed by body mass index and physical activity level. The increased lipidation of HDL found in alcohol consumers might augment the antiatherogenic effect of HDL-CH increase. In addition, the phospholipid enrichment of HDL might reduce the inflammatory response of atherogenesis.     

塔拉凉嗓含片安全性评价研究

进行了塔拉凉嗓含片的毒理试验、感官和理化指标检测,以检测其安全性。检验的结果表明:在本试验条件下,在急性经口毒性试验中,受试物塔拉凉嗓含片对受试动物小白鼠急性经口毒性试验LD50大于10000 mg/kg.bw,属实际无毒级;骨髓细胞微核试验,塔拉凉嗓含片对小白鼠骨髓细胞无致微核作用;感官和理化指标检测,结果全部在国家相关产品所允许的指标范围之内。