Effects of forest management on the carbon dioxide emissions of wood energy in integrated production of timber and energy biomass

The aim of this work was to study the sensitivity of carbon dioxide (CO₂) emissions from wood energy to different forest management regimes when aiming at an integrated production of timber and energy biomass. For this purpose, the production of timber and energy biomass in Norway spruce [Picea abies (L.) Karst] and Scots pine (Pinus sylvestris L.) stands was simulated using an ecosystem model (SIMA) on sites of varying fertility under different management regimes, including various thinning and fertilization treatments over a fixed simulation period of 80 years. The simulations included timber (sawlogs, pulp), energy biomass (small‐sized stem wood) and/or logging residues (top part of stem, branches and needles) from first thinning, and logging residues and stumps from final felling for energy production. In this context, a life cycle analysis/emission calculation tool was used to assess the CO₂ emissions per unit of energy (kg CO₂ MWh^?1) which was produced based on the use of wood energy. The energy balance (GJ ha^?1) of the supply chain was also calculated. The evaluation of CO₂ emissions and energy balance of the supply chain considered the whole forest bioenergy production chain, representing all operations needed to grow and harvest biomass and transport it to a power plant for energy production. Fertilization and high precommercial stand density clearly increased stem wood production (i.e. sawlogs, pulp and small‐sized stem wood), but also the amount of logging residues, stump wood and roots for energy use. Similarly, the lowest CO₂ emissions per unit of energy were obtained, regardless of tree species and site fertility, when applying extremely or very dense precommercial stand density, as well as fertilization three times during the rotation. For Norway spruce such management also provided a high energy balance (GJ ha^?1). On the other hand, the highest energy balance for Scots pine was obtained concurrently with extremely dense precommercial stands without fertilization on the medium‐fertility site, while on the low‐fertility site fertilization three times during the rotation was needed to attain this balance. Thus, clear differences existed between species and sites. In general, the forest bioenergy supply chain seemed to be effective; i.e. the fossil fuel energy consumption varied between 2.2% and 2.8% of the energy produced based on the forest biomass. To conclude, the primary energy use and CO₂ emissions related to the forest operations, including the production and application of fertilizer, were small in relation to the increased potential of energy biomass.     

Effects of two weeks' mandatory snack consumption on energy intake and energy balance

Objective: Our goal was to compare the effects of mandatory consumption of commercial snack products (CSPs) on energy intakes and energy balance in free‐living adults and to assess the interaction between habitual level of CSP consumption and the interventions. Research Methods and Procedures: Four groups of 18 subjects (lean and overweight, males and females) were studied using a crossover design. Subjects consumed one type of CSP (high‐carbohydrate, high‐fat, or mixed composition) at three manipulations of energy 0 MJ (control), 1.5 MJ (low‐energy), and 3.0 MJ (high‐energy) each day during three 14‐day interventions. The study design was parallel for type of CSP (macronutrient composition) and within‐subjects for energy level. Subjects self‐recorded food intakes between Days 8 and 14, and body weights were investigator‐recorded on Days 1, 8, and 15 of each intervention period. Daily energy expenditure was estimated by heart rate monitoring. Results: Daily energy intakes increased from 10.4 MJ (control) to 11.1 MJ (low‐energy) and 11.5 MJ (high‐energy) (p < 0.001), resulting in a trend (not significant) for body weight gain. Energy balance was more positive when subjects were not recording their food intakes than when they were (p < 0.001). There was a trend (not significant) for greater increases in energy intake with increasing fat content, and energy density, of the interventions. Frequent CSP consumers compensated more for the interventions than did infrequent CSP consumers (R² = 0.125, p = 0.003). Discussion: Subjects partially compensated for energy when supplemented with CSPs over 14‐day periods, although this was insufficient to prevent some increase in energy balance. The level of compensation correlated with habitual energy intake from CSPs.     

辽宁省能源消费和碳排放与经济增长的关系

在广泛收集资料的基础上,对辽宁省的能源利用效率、能源消费强度与经济增长的关系进行探索,其目的为辽宁省的节能与CO2减排及经济的快速发展提供科学依据。结果表明:辽宁整体单位GDP能耗高出全国水平52%—70%,第二产业单位GDP能耗是第三产业的5.67—8.41倍,第一产业的7.2—9.0倍;辽宁能源利用率只有全国平均水平的60%左右,第二产业能源利用效率只有第一产业的11.89%,第三产业的12.60%;GDP年增长速率大于能源消费量年增长速率,能源投入增加促进了国民生产总值的提高,但是经济增长并不是完全依赖能源消费的增长;能源消费量与经济增长的关系,呈现出"N型"曲线特征,随着GDP的增加,能源消费量出现反复上升和下降过程,辽宁省能源消费和经济增长关系没有达到长期的均衡性,尚处于非平衡的发展阶段。     

Differences of energy intake and energy expenditure of elite Taekwondo players receiving summer vs. winter intensive training

[Purpose]

This study aimed to evaluate the energy expenditure and energy intake as an experiment of energy balance of elite Taekwondo players receiving summer vs. winter intensive training.

[Methods]

The summer training group (STG, n = 15) and the winter training group (WTG, n = 18) wore an accelerometer for the measurement of energy expenditure and maintained a daily dietary record for measurement of energy intake, for seven consecutive days during summer or winter intensive training.

[Results]

The total energy expenditure (TEE) (834.1 kcal, p < .001), the total counts (1,867 counts, p = .038), and the energy expenditure during moderate (384.6 kcal, p < .001) and vigorous activity (351.8 kcal, p < .001) were significantly lower in the STG than in the WTG. On the other hand, the macronutrient intake showed that intake of energy (902.7 kcal, p < .001), carbohydrates (82.6g, p < .001), and protein (93.9g, p < .001) in the STG were significantly lower than those of the WTG. When comparing TEE and total energy intake, the STG consumed 902.7 kcal less as energy than the WTG, while the STG performed 834.1 kcal more as TEE than that of the WTG.

[Conclusion]

In conclusion, both of the summer and winter intensive training are not proper for energy balance condition. Therefore, to promote the optimal energy balance during the summer or winter intensive training period, a training and sports nutrition program based on the amount of energy expenditure and energy intake for Taekwondo players should be considered.     

Timing of potential and metabolic brain energy

The temporal relationship between cerebral electro-physiological activities, higher brain functions and brain energy metabolism is reviewed. The duration of action potentials and transmission through glutamate and GABA are most often less than 5 ms. Subjects may perform complex psycho-physiological tasks within 50 to 200 ms, and perception of conscious experience requires 0.5 to 2 s. Activation of cerebral oxygen consumption starts after at least 100 ms and increases of local blood flow become maximal after about 1 s. Current imaging technologies are unable to detect rapid physiological brain functions. We introduce the concepts of potential and metabolic brain energy to distinguish trans-membrane gradients of ions or neurotransmitters and the capacity to generate energy from intra- or extra-cerebral substrates, respectively. Higher brain functions, such as memory retrieval, speaking, consciousness and self-consciousness are so fast that their execution depends primarily on fast neurotransmission (in the millisecond range) and action-potentials. In other words: brain functioning requires primarily maximal potential energy. Metabolic brain energy is necessary to restore and maintain the potential energy.     

G protein-coupled receptors in energy homeostasis

G-protein coupled receptors (GPCRs) compromise the largest membrane protein superfamily which play vital roles in physiological and pathophysiological processes including energy homeostasis. Moreover, they also represent the up-to-date most successful drug target. The gut hormone GPCRs, such as glucagon receptor and GLP-1 receptor, have been intensively studied for their roles in metabolism and respective drugs have developed for the treatment of metabolic diseases such as type 2 diabetes (T2D). Along with the advances of biomedical research, more GPCRs have been found to play important roles in the regulation of energy homeostasis from nutrient sensing, appetite control to glucose and fatty acid metabolism with various mechanisms. The investigation of their biological functions will not only improve our understanding of how our body keeps the balance of energy intake and expenditure, but also highlight the possible drug targets for the treatment of metabolic diseases. The present review summarizes GPCRs involved in the energy control with special emphasis on their pathophysiological roles in metabolic diseases and hopefully triggers more intensive and systematic investigations in the field so that a comprehensive network control of energy homeostasis will be revealed, and better drugs will be developed in the foreseeable future.     

Efficiency of energy utilisation and voluntary feed intake in ruminants

Energy requirements of animals are most readily expressed in terms of net energy (NE), while the energy yield of feed is, at least initially, expressed in terms of metabolisable energy (ME). Energy evaluation systems 'translate' NE requirements into ME requirements (ME systems) or assign NE values to feeds (NE systems). Efficiency of ME utilisation is higher for maintenance than for production and the NE yield of a feed varies, therefore, with ME intake. In addition, energetic efficiency for maintenance and production is thought to be different for lactating and non-lactating animals and to be affected by diet quality. As a result, there are currently many national energy evaluation systems that are complex, differ in their approach and are, as a result, difficult to compare. As ruminants in most production systems are fed ad libitum, this is also the most appropriate intake level at which to estimate energetic efficiency. Analyses of older as well as more recent data suggest that ad libitum feeding (i) abolishes the effects of diet quality on energetic efficiency (almost) completely, (ii) abolishes the differences between lactating and non-lactating animals (almost) entirely and (iii) results in overall energetic efficiencies that are always close to 0.6. The paper argues that there is now sufficient information to develop an international energy evaluation system for ad libitum fed ruminants. Such a system should (i) unify ME and NE systems, (ii) avoid the systematic bias and large errors that can be associated with current systems (iii) be simpler than current systems and (iv) have as a starting point a constant efficiency of ME utilisation, with a value of around 0.6. The remarkably constant efficiency of ME utilisation in ad libitum fed ruminants could be the result of energetic efficiency as well as feed intake regulation being affected by the same variables or of a direct role of energetic efficiency in feed intake regulation. Models to predict intake on the basis of the latter hypothesis are already available for non-reproducing ruminants but remain to be developed for reproducing animals.     

江苏省能源农业发展的资源现状与发展潜力

在讨论江苏省农村生物质类型和资源总量的基础上,利用已有统计资料和数据,对江苏省能源农业发展的资源基础现状进行定量的估算,并通过对发展能源农业的种质和可利用土地、江苏省农业和畜牧业发展态势的分析研究,对江苏省能源农业的发展潜力进行了预测.研究表明,2006年江苏省农村生物质能总蕴藏量和可利用量折合标准煤分别达到14238.06万t和2311.54万t.到2010年和2015年,江苏省农村生物质能资源量折合标准煤将分别达到5390万t和6109万t.     

Dynamic energy correlation analysis of E. coli aspartokinase III and alteration of allosteric regulation by manipulating energy transduction pathways

Conformational change associated with allosteric regulation in a protein is ultimately driven by energy transformation. However, little is known about the latter process. In this work, we combined steered molecular dynamics simulations and sequence conservation analysis to investigate the conformational changes and energy transformation in the allosteric enzyme aspartokinase III (AK III) from Escherichia coli. Correlation analysis of energy change at residue level indicated significant transformation between electrostatic energy and dihedral angle energy during the allosteric regulation. Key amino acid residues located in the corresponding energy transduction pathways were identified by dynamic energy correlation analysis. To verify their functions, residues with a high energy correlation in the pathways were altered and their effects on allosteric regulation of AKIII were determined. This study sheds new insights into energy transformation during allosteric regulation of AK III and proposes a strategy to identify key residues that are involved in intramolecular energy transduction and thus in driving the allosteric process.     

脑部乳酸供能的方式

脑部存在星形胶质细胞-神经元的乳酸穿梭方式供能。单羧酸转运蛋白2(monocarboxylate transporter 2,MCT2)和MCT4的细胞特异性分布与乳酸穿梭的方向存在密切联系。MCT2和MCT4分别集中于神经元突触后膜致密区与星形胶质细胞终足膜,可能有利于N-甲基-D-天冬氨酸(N-methyl-D-asparticacid,NMDA)受体抑制的解除及循环中乳酸穿越血脑屏障。神经元和星形胶质细胞均能利用乳酸或血糖作为氧化底物。神经元中,乳酸是比血糖更为优势的氧化底物,其原因有待研究。脑部乳酸不仅来源于血糖酵解,还来源于血液循环中的乳酸及星形胶质细胞的糖原酵解。     

Temperature affects the partitioning of absorbed light energy in freshwater phytoplankton

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Einstein’ssons for energy accounting in LCA

The role and meaning of accounting for energy, including feedstock energy, is reviewed in connection to Einstein’s special theory of relativity. It is argued that there is only one unambiguous interpretation of the term energy-content: The one that corresponds tome The implications for life cycle inventories is that all discussions concerning upper heating value, lower heating value, feedstock energy, etc. are pointless as long as the motivation for choosing one or the other is not specified in relation to the safeguard subjects defined for a particular analysis (LCA or energy analysis). The subjective aspects of energy accounting schemes, even though based on mere thermodynamics, are highlighted. In inventory analysis, it is recommended that energy carriers should be accounted separately and in mass terms. For illustrative purposes, energy statistics and energy assessment are discussed in view of the safeguard subjects underlying the accounting procedures. Based on a set of theses, one possible energy accounting scheme as an indicator of the “consumption of non-renewable energy resources” within the impact assessment of LCA is sketched. It is emphasised that energy accounting schemes do not reflect environmental impacts caused by the energy sources, and the characteristics of the indicator “consumption of non-renewable energy resources” introduced here are highlighted. An erratum to this article is available at .     

GIS在生物质能源研究中的应用

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Inclusion of solvation free energy with molecular mechanics energy: alanyl dipeptide as a test case.

A combined force field of molecular mechanics and solvation free energy is tested by carrying out energy minimization and molecular dynamics on several conformations of the alanyl dipeptide. Our results are qualitatively consistent with previous experimental and computational studies, in that the addition of solvation energy stabilizes the C5 conformation of the alanyl dipeptide relative to the C7.     

能量消耗C指标在评价乒乓球运动员多球练习中能量消耗的应用*

目的:研究周期类运动能量消耗^C指标在评价乒乓球多球练习中能量消耗应用的可行性。方法:11名某大学代表队的乒乓球运动员(18±1 yrs, 177±2 cm, 71±3 kg,运动水平≥二级)自愿参加了1次跑台递增负荷测试和2次(正手和反手)发球机多球递增频率测试(3 min × 6级,频率为35~85 stroke·min^-1)。用便携式气体代谢仪和心率监测仪检测3次测试的呼吸气体和心率,计算每种频率下每次击球所消耗的能量;采集运动前后的耳血进行血乳酸分析。结果:乒乓球前冲弧圈多球练习的能量消耗^C随击球频率的增加而下降(P＜0.05)。6种击球频率下,正手前冲弧圈的能量消耗^C都高于反手,且差异在35、45、55、65和85 stroke·min^-1时显著(P＜0.05)。能量消耗^C与频率的关系公式分别为y=166.4x^-0.731(R²=0.9731)和y=33.21x^-0.392(R²=0.8423),其中y为能量消耗^C(单位为J·stroke^-1·kg^-1),x为击球频率(单位为stroke·min^-1)。结论:周期类运动项目的能量消耗^C可应用于评价乒乓球运动员单一技术动作多球练习的能量消耗,反映乒乓球运动员在不同击球频率下的击球效率。     

Seasonal changes in energy and the energy cost of spawning in Gulf of Alaska Pacific cod

In the Gulf of Alaska, adult Pacific cod exhibited an annual cycle of condition, gonad index and liver index in which maximum values occurred in ripe fish in March and minima in July. About 30–31 % of prespawning stored energy was expended during the spawning effort. The energy associated with spawning derived from liver (24% and 18%), somatic tissue (22% and 33%) and gonad (53% and 48%) for females and males, respectively. Liver index and gonad index at the time of sampling were directly related in females, but in males gonad index was best related to liver index 1–3 months earlier.
The Pacific cod is very similar to the Atlantic cod in terms of energy cycling, maximum gonad sizes, energy expended during spawning and gonadal contribution to energy expenditure. However, in Pacific cod, somatic tissue contributes markedly to energy expended during reproduction. The Pacific cod cod differs from the walleye pollock with respect to gonad index (13% and 20%ν. 20% and 8% for females and males, respectively), spawning weight loss (25%ν. 38%), liver energy loss during spawning (71%ν. 55%) and energy cost of spawning.     

Polar hydrogen positions in proteins: Empirical energy placement and neutron diffraction comparison

A method for the prediction of hydrogen positions in proteins is presented. The method is based on the knowledge of the heavy atom positions obtained, for instance, from X-ray crystallography. It employs an energy minimization limited to the environment of the hydrogen atoms bound to a common heavy atom or to a single water molecule. The method is not restricted to proteins and can be applied without modification to nonpolar hydrogens and to nucleic acids. The method has been applied to the neutron diffraction structures of trypsin ribonuclease A, and bovine pancreatic trypsin inhibitor. A comparison of the constructed and the observed hydrogen positions shows few deviations except in situations in which several energetically similar conformations are possible. Analysis of the potential energy of rotation of Lys amino and Ser, Thr, Tyr hydroxyl groups reveals that the conformations of lowest intrinsic torsion energies are statistically favored in both the crystal and the constructed structures.