Energy-related Factors Research Articles

Research on EA-Xgboost Hybrid Model for Building Energy Prediction

Building energy forecast plays an important role in Intelligent Building. Due to its non-stationarity and uncertainty, the prediction accuracy of existing methods need to be further improved. In view of this problem, propose the EA-XGBoost model, which combines Empirical Mode Decomposition (EMD), ARIMA and XGBoost model to predict building energy consumption. First, EMD is used to decompose the consumption data into multiple Intrinsic Mode Functions(IMF). Afterwards, ARIMA model is applied for each IMF to get regression result, then sum the results and calculate the residual. Taking the residual as an input feature of XGBoost, combined with other energy-related factors such as dry and wet bulb temperature, using XGBoost after Grid-Search to predict building energy consumption data. Compared with ARIMA and XGBoost model, EA-XGBoost hybrid model performs best in forecasting building energy consumption dataset which provided by the US National Renewable Energy Laboratory. The experiment shows the feasibility and effectiveness of the new model.

Energy periphery: Uneven development and the precarious geographies of low-carbon transition

The paper introduces the concept of energy periphery to interrogate place-based perspectives on the co-production of uneven geographical development, energy vulnerabilities and low carbon transitions. Energy periphery is defined as places that are systematically disadvantaged through the whole energy system due to their inferior position within the asymmetrical spatial distribution of economic, political and symbolic resources and capabilities. Within an energy periphery, energy-related factors are combined with other place-based conditions to subject their communities to a compound and circular effect of precarious energy experiences. The notion of energy periphery is underpinned by insights from the spatial justice, core-periphery and energy justice theories. Using the case of Wales, the paper demonstrates the multi-dimensional and multi-scalar character of energy peripheralisation, including political underrepresentation, the absence of economic agglomeration advantages, and dependence on off-grid fuels, energy inefficient homes and other ‘backward’ technologies and practices. Social and spatial contingencies of energy vulnerability factors are outlined. Contrary to common discourses, energy transition further disadvantages energy peripheries and reproduces a fragmented socio-spatial landscape. The study overall demonstrates the importance of considering energo-socio-spatial relationships to better understand uneven energy transitions and social change more generally.

Driving factors of water-energy nexus in China

Water and energy are intertwined during their production and consumption processes. Static assessments and simulations of the water-energy nexus among production and consumption are important for determining the mechanism behind the nexus; however, dynamic studies can help determine the most important factors that influence the development of the water-energy nexus, which can provide new insights for shaping energy and water synergetic management. Thus, we probed the driving factors of the water-energy nexus in China through structural decomposition analysis from 1990 to 2014 and decomposed the water consumption of different consumers into six energy related factors: the water-energy nexus coefficient, the energy intensity, the production structure, the consumption volume per capita of final consumers, consumption patterns, and the population. The results showed that the consumption volume, which indicates the consumption levels of different consumers, contributed 156% of the increase of the total energy related water consumption in 2014 compared with that in 1990. Additionally, the energy intensity is the most important driving factor that can reduce the total water consumption of all consumers (household, government, gross fixed capital format, etc.), accounting for −271% of the water consumption in 2014. The consumption patterns, i.e., expenditures on various products in different sectors, also show positive impacts on water consumption conservation for the gross fixed capital format and government, although they can aggravate the water consumption in households. The investigation of the driving forces for different consumers also shows that prosperity in the real estate industry and other related industries has indirectly driven more water flow into gross fixed capital investments and the government, which negatively affects the sustainable water consumption goal in China.

Dead end for endemic plant species? A biodiversity hotspot under pressure

Tropical high mountains are hosting important hot spots of biodiversity on small mostly remote areas. Recently, these precious ecosystems are under threat from land use change and climate change coupled with other local drivers of biodiversity loss. Along the East African Afroalpine ecosystems, area above the treeline have experienced long-term spatial isolation and extreme climatic conditions (climatic factors such as low mean temperature, diurnal freeze-thaw cycles and other energy-related factors) which lead to the formation of “Sky Island” like ecosystems that are rich in endemics and unique. The Bale Mountains of Ethiopia are home to the largest tropical alpine plateau in Africa, with no spacious high summits that provide space for upward shift of species. Here, we studied plant species diversity and distribution patterns and tested potential future impacts of climate change induced warming on those patterns. This study is based on distribution data acquired from nested circular plots along an elevational gradient ranging from 2000m asl to the highest elevation (4385 m asl). We find hump shaped species richness patterns on both aspects, i.e. the dry north-eastern and the wet monsoon exposed south-western escarpment. In addition, the proportion of endemic species increases monotonically towards the summit on all slopes. Based on our data and literature, we project future climate impact for three regional warming scenarios (+2 °C, + 3 °C and + 4 °C). We quantify the future range of 114 endemic plant species based on their current occurrence records applying a lapse rate of 0.6 °C per 100 m of elevation. We find that future climate change would significantly alter species distribution patterns with pronounced impact on the unique ecosystems and endemic species restricted to the afroalpine plateau. Very likely this will be leading to the extinction of many endemic species.

Quantifying the geographical distribution effect on decreasing aggregated nitrogen oxides intensity in the Chinese electrical generation system

Over the past 20 years, the spatial distribution of electrical generation and its relationship to cross-regional power transmission has impacted China's power generation system and significantly affected the total amount of NO x and the aggregated nitrogen oxides intensity (ANI) of the system. An investigation of the driving mechanisms of ANI that considers the unevenness of regional electricity generation will be crucial to future improvements in the NO x efficiency of the electrical generation system in China. In this study, we built a decomposition model for ANI by incorporating the spatial distribution of electrical generation and found that the spatial distribution of electricity generation together with energy-related factors gradually caused decreases in ANI. The efficiency of electricity generation presented the dominant inhibitory effect on ANI, but its effect size has weakened since 2010. In contrast, the fossil fuel structure of thermal power shows an increasingly positive effect on changes in ANI. The primary energy composition only slightly affected changes in ANI. Moreover, the changed geographical distribution of electricity generation is non-negligible and has a positive effect on reduction of the ANI of the Chinese electrical generation system. The transferred amount of local NO x emissions by cross-provincial electricity transmission, however, could cause lead to additional environmental costs for generators. This issue should receive more attention in the future.

Development of a non-domestic building refurbishment scheme for Malaysia: A Delphi approach

Building refurbishment is a key in promoting environmentally sustainable development due to its potential for reducing greenhouse gas emissions and energy consumption associated with existing buildings. The general metrics for assessing the impacts of refurbishment have not been established for existing buildings in most of the countries. In Malaysia, there is currently no single environmental assessment scheme for building refurbishment. The existing environmental assessment schemes are not sufficiently robust, as they do not include factors such as quality of services and economics. It is essential to have a customised suite of sustainability schemes specifically designed for the Malaysian context to facilitate best practice for non-domestic refurbishment assessment. A comprehensive Delphi process was developed to assist in the identification of suitable assessment schemes for use in non-domestic buildings. Three successive rounds of surveys were conducted with ten Delphi experts with expertise in sustainability and green assessment. The study revealed that energy related factors such as air-conditioning were ranked as the most important assessment theme for refurbishment, followed by indoor environmental quality and water assessment. The findings of this research will be used to develop a weighting system by using the analytic hierarchy process in the next research stage, leading to a complete refurbishment environmental assessment scheme.

Evaluation of the energy budget and energy use efficiency in wheat production under various crop management practices in China

Developing energy-saving and high-efficiency crop managements is required for food and energy security. Huang-Huai-Hai Plain produces more than 60% of the wheat in China. However, no published studies have investigated the energy budget of wheat production in this area. Using an input-output energy analysis from 2012 to 2014, we assessed energy flow of various managements. The average energy input and output ranged from 37.5 to 57.4 and 170.9–263.9 GJ ha−1, respectively. Compared with rainfed wheat (W1), irrigated wheat presented significantly higher energy inputs and outputs. Compared with farmers' practices (W2), optimized management based on soil water content (SWC) at depths of 0–20 (W3) and 0–40 cm (W4) reduced energy use; however, this reduction did not occur at soil depths of 0–60 cm (W5). Among four irrigated managements, W4 produced the highest energy output with the lowest energy input. Moreover, W4 presented the highest net energy, energy use efficiency, and energy productivity, which were 8.2%, 15.6%, and 14.9% higher than those presented by W2, respectively. The lowest specific energy in W4 indicated that the energy consumed to produce 1 kg of wheat can be substantially reduced via efficient water management. SWC-based water management had a significant positive effect on energy-related factors without sacrificing crop productivity.

Interest-aware energy collection & resource management in machine to machine communications

The emerging paradigm of Machine to Machine (M2M)-driven Internet of Things (IoT), where physical objects are not disconnected from the virtual world but aim at collectively provide contextual services, calls for enhanced and more energy-efficient resource management approaches. In this paper, the problem is addressed through a joint interest, physical and energy-aware clustering and resource management framework, capitalizing on the wireless powered communication (WPC) technique. Within the proposed framework the numerous M2M devices initially form different clusters based on the low complexity Chinese Restaurant Process (CRP), properly adapted to account for interest, physical and energy related factors. Following that, a cluster-head is selected among the members of each cluster. The proposed approach enables the devices of a cluster with the support of the cluster-head to harvest and store energy in a stable manner through Radio Frequency (RF) signals adopting the WPC paradigm, thus prolonging the operation of the overall M2M network. Each M2M device is associated with a generic utility function, which appropriately represents its degree of satisfaction in relation to the consumed transmission power. Based on the distributed nature of the M2M network, a maximization problem of each device's utility function is formulated as a non-cooperative game and its unique Nash equilibrium point is determined, in terms of devices’ optimal transmission powers. Considering the devices’ equilibrium transmission powers, the optimal charging transmission powers of the cluster-heads are derived. The performance of the proposed approach is evaluated via modeling and simulation and under various topologies and scenarios, and its operational efficiency and effectiveness is demonstrated.

Effect of hormonal and energy-related factors on plasma adiponectin in transition dairy cows

In transition dairy cows, plasma levels of the insulin-sensitizing hormone adiponectin fall to a nadir at parturition and recover in early lactation. The transition period is also characterized by rapid changes in metabolic and hormonal factors implicated in other species as positive regulators of adiponectin production (i.e., negative energy balance, lipid mobilization) and others as negative regulators (i.e., reduced leptin and insulin and increased growth hormone and plasma fatty acids). To assess the role of onset of negative energy balance and lipid mobilization after parturition, dairy cows were either milked thrice daily (lactating) or never milked (nonlactating) for up to 4 wk after parturition. Plasma adiponectin was 21% higher across time in nonlactating than lactating cows. Moreover, nonlactating cows recovered plasma adiponectin at similar rates as lactating cows even though they failed to lose body condition. Next, we assessed the ability of individual hormones to alter plasma adiponectin in transition dairy cows. In the first experiment, dairy cows received a constant 96-h intravenous infusion of either saline or recombinant human leptin starting on d 8 of lactation. In the second experiment, dairy cows were studied in late pregnancy (LP, starting on prepartum d -31) and again in early lactation (EL, starting on d 7 postpartum) during a 66-h period of basal sampling followed by 48 h of hyperinsulinemic-euglycemia. In the third experiment, cows were studied either in LP (starting on d -40 prepartum) or EL (starting on d 7 postpartum) during a 3-h period of basal sampling followed by 5 d of bovine somatotropin treatment. Plasma adiponectin was reduced by an average of 21% in EL relative to LP in these experiments, but neither leptin, insulin, or growth hormone treatment affected adiponectin in LP or EL. Finally, the possibility that plasma fatty acids repress plasma adiponectin was evaluated by intravenous infusion of a lipid emulsion in nonpregnant, nonlactating cows in the absence or presence of glucagon for 16 consecutive hours. The intralipid infusion increased plasma fatty acid concentration from 102 to over 570 µM within 3 h but had no effect on plasma adiponectin irrespective of presence or absence of glucagon. Overall, these data suggest that energy balance around parturition may regulate plasma adiponectin but do not support roles for lipid mobilization or sustained changes in the plasma concentration of leptin, insulin, growth hormone, or fatty acids.

Impacts of energy consumption, energy structure, and treatment technology on SO2 emissions: A multi-scale LMDI decomposition analysis in China

Air pollution is increasingly a focus of concern worldwide due to its adverse impacts on human health and profound influences on global ecosystem. Although the existing studies have paid much attention to the causes of pollutant emissions, they fail to distinguish between direct and indirect factors, yielding the mixed results. Direct causes denote energy-related factors, as air pollutants are mainly produced by energy utilization directly, while indirect elements refer to socio-economic factors, as these factors act on pollutant emissions through affecting energy-related aspects. This paper investigated the impacts of three dominant direct factors: total energy consumption (EC), energy structure (ES) and treatment technology (TT) on sulfur dioxide (SO2) emissions in China during 1995–2014 using the logarithmic mean Divisia Index method. Distinguished from the previous studies which took particular interest in SO2 emissions from the industrial sector, this study put the total amount of SO2 emissions as the target. The results show that increased EC was the main reason for SO2 enhancement, while increasingly advanced TT played a dominant role in inhibiting the emissions throughout the study period. In contrast, ES had an unusually slight effect on SO2 emissions due to its minor variation in the meantime. On regional scale, the differences in relative contribution rates (RCRs) of EC, ES and TT among the eastern, central and western regions all gradually decreased over time; EC in central region had the largest improved effect, ES in eastern region held the greatest reduction effect, and TT in western region got the biggest inhibitory effect. At provincial level, most provinces (60%) had relatively quick EC growth and slow ES adjustment (i.e., reducing the coal consumption rate); only Beijing, Tianjin, Shanghai and Sichuan had a relatively slow growth of EC and quick decrease in the percentage of coal consumption. Further, the projection of SO2 emissions in four scenarios from 2015 to 2020 based on a grey projection model indicated that controlling both EC and ES would be the most efficient approach to SO2 abatement followed by individually controlling EC and ES.

Energy-related influences on variation in breastfeeding duration among indigenous Maya women from Guatemala.

The causes of variation in breastfeeding duration in humans are poorly understood, but life history factors related to maternal energetics drive much of the variation in lactation duration in nonhuman animals. With this in mind, we investigated whether four energy-related factors influence variation in breastfeeding duration in a non-industrial human population: (1) mortality risk during mother's development (assessed via mother's adult height), (2) reliance on nutrient-dense weaning foods, (3) access to and need for help with infant feeding and care ("allomaternal care"), and (4) maternal tradeoffs between current and future reproduction (measured via child's birth order). The data pertain to 51 Kakchiquel-speaking Maya mothers and 283 children from a village in rural Guatemala. We developed a linear mixed model to evaluate the relationships between breastfeeding duration and the energy-related factors. Duration of breastfeeding was associated with two of the energy-related factors in the ways we predicted but not with the other two. Contrary to predictions, taller mothers breastfed for shorter periods and we found no evidence that weanling diet quality impacts breastfeeding duration. As predicted, women who had more help with infants breastfed for shorter periods, and later-born infants breastfed longer than earlier-born ones. The results regarding allomaternal care suggest that help reduces mothers' lactation demands. The energy saved may be redirected to increasing fecundity or investment in other children. The birth order result suggests that children born to mothers nearing reproductive senescence receive higher levels of investment, which likely impacts children's fitness.

Evaluating rural low-carbon communities: A study of Guangdong Province, China

As the Chinese economy has rapidly developed, energy consumption and carbon emissions in China’s rural areas have also steadily increased. Rural communities are the most important component of rural areas; as such, developing low-carbon communities will likely promote reductions in rural carbon emissions. As one of the low-carbon pilot provinces, Guangdong Province has gradually constructed low-carbon communities; however, neither the province nor China as a whole has established a system for evaluating different energy-related factors in rural low-carbon communities. Using real-world conditions in Guangdong Province, combined with the general parameters associated with low-carbon communities, this study evaluated six categorical factors: carbon reduction performance, low-carbon planning, energy consumption, low-carbon transportation, environment and resources, and low-carbon management and living. These categories were measured using several suitable indices according to the SMART principle. The baseline value corresponding to each index was determined by two zones: the Pearl River Delta zone and the non-Pearl River Delta zone. Each index weight was calculated using a method that combines a Monte Carlo simulation and an Analytical Hierarchy Process. Ultimately, one typical community was selected for a pilot evaluation. The sensitivity analysis of each index was conducted using the One-At-a-Time (OAT) method. Establishing this system is beneficial for promoting rural low-carbon communities construction in Guangdong Province, and supports system evaluation and adoption in rural low-carbon communities. This study’s system can also provide a reference case and experience for the Chinese government, as it establishes a system for evaluating rural low-carbon communities at the national level.

제로에너지 빌딩 평가를 통한 제도적 개선방안에 대한 조사 연구

전 세계에서 건물 내에서 사용되고 있는 에너지는 지구온난화의 주요원인일 뿐만 아니라 기후변화 대응을 위해 다루어져야할 주요 과제이다. 본 연구는 빌딩을 대상으로 사용되고 있는 에너지의 평가를 통하여 개선사항을 도출하고자 하였으며 이를 위하여 제로에너지빌딩을 검토하고 영향인자들을 조사하였다. 또한 실제 건물을 대상으로 환경적 요인과 환경부하로 구분하여 평가항목을 설정하였으며 평가결과를 토대로 개선사항을 제안하고자 하였다. 그 결과 제로에너지빌딩을 구현하기 위한 평가단계에서는 건물부지의 지형과 기후변수가 고려되어야 하며, 신재생에너지의 이용, 저장 및 관리 측면에서는 비용 상승에 따른 제도적 지원이 필요한 것으로 나타났다. 또한 제로에너지 빌딩에서는 에너지 효율이 중요하나 현재 건물 내에서 사용되는 에너지 소비량을 확인하고 관리하기 위해서 모니터링과 같은 평가항목이 필요하다. 이와 같은 모니터링 결과를 사용해서 세부적인 체계로서 절약과 낭비 에너지에 대하여 국내 실정에 적적한 체계적인 관리가 요구된다. Energy use has been recognized worldwide as a main cause of global warming and it is at the center of climate change. In this study, problems and measures of zero-energy building construction are investigated and analyzed. Based on the results, evaluation criteria of the zero-energy building are suggested. Performance related factors(Q) representing the environmental grade were divided into three categories as outdoor, indoor environment and maintenance. Energy related factors(LR) representing the energy load were divided into an energy, materials & resources, water cycle management, land use and transportation. Detailed fifty three items are listed for the evaluation under the consideration of energy, water cycle management sections gave weight. Upon receiving the first in the environment friendly certification system, Seoul Central Post Office and Seoul Metropolitan Water Supply Center evaluated. The reason why this score difference is due to lack of use of new generation energy building construction is required expensive costs so need expansion of governmental support. This effort is successful zero energy building construction and copes with global warming and climate change.

Abstract 799: Interaction between meat and fish intake and genes involved in hormones, inflammation and energetic factors, and risk of breast cancer among Hispanic and Non-Hispanic White women: The Breast Cancer Health Disparities Study

Abstract Previously, we reported associations between breast cancer (BC) risk and tuna intake in non-Hispanic White (NHW) and Hispanic women, and processed meat intake among Hispanic women only. We also reported associations with SNPs in genes involved in the Convergence of Hormones, Inflammation, and Energy-related Factors (CHIEF) network. Given the multifactorial nature of BC etiology, we tested for interactions (GxE) between meat/fish intake and SNPs in selected CHIEF pathways using a set-based method that aggregates SNPs into groups for GxE association testing.The study population included Hispanic (1046 cases, 1331 controls) and NHW (1234 cases, 1468 controls) women from two US population-based case-control studies that are part of the Breast Cancer Health Disparities Study. Harmonized meat intake variables were dichotomized, and include red meat, processed meat, poultry, fish, and tuna. 734 SNPs were grouped into 107 genes based on loci. Genes were further grouped into 7 pathways based on biological function: CHIEF core, ALOX/COX, Interleukins, JAK/STAT/SOC, TLR/TNF, MAPK, and TGF-â. We performed the analysis in a top-down fashion, sequentially testing for interactions between meat/fish intake and pathways, genes within pathways, and SNPs within genes. To test pathways and genes, we used a set-based GxE approach that extends the adaptive rank truncated product (ARTP), and to test individual SNPs we used logistic regression. At gene and SNP level analyses, we applied Bonferroni corrections for the number of genes or SNPs tested. Analyses were stratified by ethnicity. Models were adjusted for study, age, education, menopausal status, family history of breast cancer, parity, body mass index, physical activity, education, intake of alcohol, fiber, calories, fat, carbohydrates, proteins, and genetic ancestry. We report results that showed statistically significant interactions at both pathway and gene levels. Analyses were conducted using the R programming language. Among NHW women, pathway-level analyses using ARTP identified an interaction between poultry intake and the interleukin/cytokine pathway, which was driven by the IL17A gene (2 SNPs); poultry intake was inversely associated with BC risk among carriers of the minor alleles in this gene. Among Hispanics, ARTP analyses identified an interaction between tuna intake and total fish intake and the Jak/Stat/SOC pathway, which was driven by STAT5A (tuna: 2 SNPs) and STAT5B (total fish and tuna: 3 SNPs). The positive associations between fish or tuna and BC risk were restricted to carriers of minor alleles in these two genes. Overall, our findings suggest a role for poultry and fish intake in chronic inflammation and tumor growth promotion in breast carcinogenesis and highlight specific genes that may play roles in these carcinogenic pathways. Citation Format: Andre E. Kim, Juan Pablo Lewinger, Shirong Zhang, Roger K. Wolff, Laura Fejerman, Esther M. John, Gabriela Torres-Mejia, Jennifer S. Herrick, Stephanie D. Boone, Avonne E. Connor, Lisa M. Hines, Kathy B. Baumgartner, Anna Giuliano, Martha L. Slattery, Mariana C. Stern. Interaction between meat and fish intake and genes involved in hormones, inflammation and energetic factors, and risk of breast cancer among Hispanic and Non-Hispanic White women: The Breast Cancer Health Disparities Study. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 799.

Enhanced integration of energy-related considerations in discrete event simulation for manufacturing applications

In order to allow for truly holistic considerations, as intended in the Digital Factory concept, energy-related factors need to be considered. This has not been widely implemented for discrete event simulation (ie, material flow simulation) in industrial companies, yet, even though it may foster the energy efficiency within production sites considerably. A primary reason for the lack of acceptance is that previously discussed approaches did not meet the users’ requirements. This paper discusses how a suitable extension (eniBRIC), which renders energy-related considerations possible within material flow simulation, can be developed paying heed to both user requirements and the state of the art. A special focus is set on its implementation in Siemens Tecnomatix Plant Simulation. The workflow for the integration of the extension into existing and new simulation models is outlined. Opportunities for its utilisation in specific application examples, as well as the associated extra time and effort are discussed.

Impacts of energy-related CO2 emissions in China: a spatial panel data technique

Since carbon dioxide (CO2) emissions cause great concern around the world, a large amount of literature focuses on the impact factors of CO2 emissions. However, there is little specific guidance on the spatial effects of variables and regional characteristics of CO2 emissions in China. Based on spatial panel methods, this paper used a STIRPAT (stochastic impacts by regression on population, affluence and technology) model to examine the impact of energy-related factors on CO2 emissions in China. Then, the spillover effects of China’s provincial per capita CO2 emissions have been tested. The results indicate that there exist obvious spatial correlation and spatial agglomeration features in spatial distribution of per capita CO2 emissions. Spatial economic model is demonstrated to offer a greater explanatory power than the traditional non-spatial panel model. Moreover, GDP per capita, energy intensity, industrial structure and urbanization have positive and significant effects on CO2 emissions, while the coefficient of population is not significant. According to these results, this paper proposes some policy suggestions on reducing China’s CO2 emissions.

Isolation and detection of transcript-derived fragments (TDFs) in NaCl-stressed black locust (Robinia pseudoacacia L.) using cDNA-AFLP analysis

Plant physiology and biochemistry are both affected by salinity, which is an important abiotic stressor. In this study, we identified transcript-derived fragments (TDFs) in response to salt stress in black locust (Robinia pseudoacacia L.) using cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis. Seventy-four TDFs were identified in the leaves of two-year-old plants after NaCl treatment (500 mM for 0, 5, 10 and 15 days). Based on the gene ontology (GO) terminology, 30 TDFs shared high homology with known genes and were classified into 6 groups: metabolism-related factors, defense-related proteins, transcription factors, stress and signal transduction-related factors and energy-related factors. Eight TDFs were selected for further study, and their expression patterns in the leaves were verified by real-time polymerase chain reaction (RT-PCR) at different stages of salt stress. Our data provide a theoretical basis for research on the mechanisms of salt tolerance in woody plants.

Temperature and food constraints in wintering birds — an experimental approach in montane Mediterranean oakwoods

Although energy is a major driver of global patterns of biodiversity and species distribution, the test of species-energy relationships needs further development using fine-grained approaches involving different functional groups of species and small geographical scales of known characteristics (habitat heterogeneity, food availability, direct measures of temperature). We carried out an experiment over a broad range of habitat structure and environmental conditions to disentangle the effects of two different energy measures on the small-scale variation of habitat use in winter: one directly related to food resources (manipulated food availability with artificial feeders), and another related to thermoregulatory costs (night temperature). The spatial variation in abundance of a guild of tree-gleaning birds wintering in montane Mediterranean oakwoods of Central Spain was positively related to both components of energy availability (temperature and food resources), even in these mild Mediterranean montane forest of southern Europe. Spatial variation in consumption of food from artificial feeders was negatively related to spatial variation in temperature. The influence of food availability on bird abundance was mediated by vegetation structure, with a lower influence in maturer oakwoods. This study highlights the important role of the energy-related factors, over habitat structure, in determining winter abundance of the studied tree-gleaning guild.

Distribution pattern of trees along an elevation gradient of Eastern Himalaya, India

We examined the patterns of tree species richness, density and basal area in the Eastern Himalayan elevation gradient, and evaluated the roles of geometric constraints and environmental factors for the observed pattern. We followed the quadrat sampling method for this study at 23 different locations along a 300–4700 m elevation gradient in Sikkim. We used regression analysis to establish elevational pattern of trees (species richness, density and basal area) and to relate environmental factors with tree species and density. We also tested geometric constraints on species distribution by comparing empirical species richness with null model predictions generated by a Monte Carlo Simulation Programme ( McCain, 2004). We observed a total of 3874 individual trees belonging to 171 species and 58 families. Tree species richness depicted unimodal pattern with a peak at 1500 m, whereas basal area peaked at 1900 m. Although density did not follow a uniform pattern, maximum value was observed at 3050 m. Climatic and energy related factors–rainfall, temperature, moisture index (MI) and actual evapotranspiration (AET)-correlated positively with tree species richness. The Mid-domain effect null model showed significant deviation of empirical richness from simulated species richness. Stepwise regression revealed that combined effects of energy (surrogated by temperature), productivity (surrogated by AET) and precipitation (reflected by MI) influenced observed tree species patterns in the Eastern Himalayan elevation gradient although historical and spatial factors might interplay.

Genetic Variation of the Ghrelin Signaling System in Females With Severe Alcohol Dependence

Central ghrelin signaling is required for the rewarding effects of alcohol in mice. Because ghrelin is implied in other addictive behaviors such as eating disorders and smoking, and because there is co-morbidity between these disorders and alcohol dependence, the ghrelin signaling system could be involved in mediating reward in general. Furthermore, in humans, single nucleotide polymorphisms (SNPs) and haplotypes of the pro-ghrelin gene (GHRL) and the ghrelin receptor gene (GHSR) have previously been associated with increased alcohol consumption and increased body weight. Known gender differences in plasma ghrelin levels prompted us to investigate genetic variation of the ghrelin signaling system in females with severe alcohol dependence (n = 113) and in a selected control sample of female low-consumers of alcohol from a large cohort study in southwest Sweden (n = 212). Six tag SNPs in the GHRL (rs696217, rs3491141, rs4684677, rs35680, rs42451, and rs26802) and four tag SNPs in the GHSR (rs495225, rs2232165, rs572169, and rs2948694) were genotyped in all individuals. We found that one GHRL haplotype was associated with reports of paternal alcohol dependence as well as with reports of withdrawal symptoms in the female alcohol-dependent group. Associations with 2 GHSR haplotypes and smoking were also shown. One of these haplotypes was also negatively associated with BMI in controls, while another haplotype was associated with having the early-onset, more heredity-driven, type 2 form of alcohol dependence in the patient group. Taken together, the genes encoding the ghrelin signaling system cannot be regarded as major susceptibility genes for female alcohol dependence, but is, however, involved in paternal heritability and may affect other reward- and energy-related factors such as smoking and BMI.