Biomass energy: the scale of the potential resource

Increased production of biomass for energy has the potential to offset substantial use of fossil fuels, but it also has the potential to threaten conservation areas, pollute water resources and decrease food security. The net effect of biomass energy agriculture on climate could be either cooling or warming, depending on the crop, the technology for converting biomass into useable energy, and the difference in carbon stocks and reflectance of solar radiation between the biomass crop and the pre-existing vegetation. The area with the greatest potential for yielding biomass energy that reduces net warming and avoids competition with food production is land that was previously used for agriculture or pasture but that has been abandoned and not converted to forest or urban areas. At the global scale, potential above-ground plant growth on these abandoned lands has an energy content representing approximately 5% of world primary energy consumption in 2006. The global potential for biomass energy production is large in absolute terms, but it is not enough to replace more than a few percent of current fossil fuel usage. Increasing biomass energy production beyond this level would probably reduce food security and exacerbate forcing of climate change.     

Changing patterns of resource allocation in a London teaching district.

The health plans of the Tower Hamlets district management team were studied to determine what effects the report of the Resource Allocation Working Party and the White Paper "Priorities in the Health and Social Services" have had on resource allocation in a teaching district. The study showed that at present acute services are allocated a greater proportion of the district budget than occurs nationally, while geriatrics, mental health, and community services receive proportionately less. In the next three years spending on acute services is expected to decrease, while spending on geriatric facilities and community services will increase. Nevertheless, cuts in acute services will take place mainly through a reduction in the number of beds serving a community function, concentrating all acute services in the teaching hospital. Services to the district might be better maintained by creating a community hospital to meet the needs of patients who would otherwise need to be accommodated in acute beds with unnecessarily expensive support services.     

Biomass allocation patterns in forests growing different climatic zones of China

Key message

Temperature generally explained variation in branch and leaf biomasses, whereas stem and root biomasses–temperature relationships restricted certain age stages may not hold at broader age ranges.

Abstract

In this study, biomass data for alpine temperate Larix forest, alpine Picea-Abies forest, temperate typical deciduous broadleaved forest, temperate Pinus tabulaeformis forest, temperate mixed coniferous-broadleaved forest, montane Populus-Betula deciduous forest, subtropical evergreen broadleaved forest, subtropical montane Cupressus and Sabina forest, subtropical Pinus massoniana forest and subtropical Cunninghamia lanceolata forest were used to examine the effect of temperature on biomass allocations between organs. The data of the ten forests were classified as ≤30, 31–60 and >60 years, to test whether biomass allocations of these age group forests vary systematically in their responses to temperature. With increasing mean annual temperature, branch and leaf biomasses significantly increased in ≤30, 31–60 and >60 years and all age groups; stem biomass significantly increased in ≤30-, 31–60- and >60-year groups, but no significant trend in all age groups; Root biomass significantly increased in 31–60, >60 years and all age groups, but had no response to mean annual temperature in the 30-year group, which suggest that root biomass allocation in response to temperature is dependent upon forest age. We conclude that temperature generally explained variation in branch and leaf biomasses, whereas stem and root biomasses–temperature relationships restricted certain age stages may not hold at broader age ranges.

     

Weighting in the dark: resource allocation in the new NHS.

National allocation of resources to regional health authorities and by them to districts is now determined by a weighted capitation formula. The national formula was derived from regression analysis, with hospital utilisation as an index of need for health care--a method which has fundamental limitations. This paper argues that the search for an empirically based resource allocation formula of high precision in the name of promotion of equity is largely fruitless given the impossibility of measuring the true need for, and costs of, providing health care, especially with the limited data available. The inclusion of measures of social deprivation is also poorly thought out. The availability of data from the 1991 census, which included a question regarding long-standing illness, together with the intention of the Department of Health to review the weighted capitation formula using this information may stimulate much work but little light. It is essential that the impact of resource allocation formulas is justifiable on grounds other than the composition of any particular formula.     

Biomass for energy in the European Union - a review of bioenergy resource assessments

ABSTRACT: This paper reviews recent literature on bioenergy potentials in conjunction with available biomass conversion technologies. The geographical scope is the European Union, which has set a course for long term development of its energy supply from the current dependence on fossil resources to a dominance of renewable resources. A cornerstone in European energy policies and strategies is biomass and bioenergy. The annual demand for biomass for energy is estimated to increase from the current level of 5.7 EJ to 10.0 EJ in 2020. Assessments of bioenergy potentials vary substantially due to methodological inconsistency and assumptions applied by individual authors. Forest biomass, agricultural residues and energy crops constitute the three major sources of biomass for energy, with the latter probably developing into the most important source over the 21st century. Land use and the changes thereof is a key issue in sustainable bioenergy production as land availability is an ultimately limiting factor.     

Experimental manipulation of patterns of resource allocation in the growth cycle and reproduction of Smyrnium olusatrum L.

Plants of the monocarpic (normally biennial) Smyrnium olusatrum (Umbel]iferae) were grown in pots in soil at a high or low nutrient regime. Some plants receiving full nutrients were grown in a heated glasshouse with 16 h days. The remainder were grown without supplementary lighting or heat and included control plants and others which received surgical treatment after ten months growth: deradication (removal of half of the root stock); defoliation; deradication and defoliation. The distribution of plant biomass and of phosphorus were analyzed at the time of seed set.
Patterns of allocation of dry matter and phosphorus were quite different and were significantly altered by treatments, which produced a range of allocation to reproductive structures ranging from 21 to 74% of total phosphorus and 12 to 35% of dry matter.
Distribution patterns of total phosphorus are discussed in terms of the potential demands being made by alternative structures and functions over the life cycle of the plants.     

Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5–39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Life history implications of allocation to growth versus reproduction in dynamic energy budgets

We compare the implications of determinate vs. indeterminate growth of a parthenogenetic iteroparous ectotherm at constant food density in the context of the dynamic energy budget theory, which specifies the tight links between life history traits, such as feeding, aging, growth and reproduction. We do a comparative analysis using, as measure of fitness, the life span reproduction, the population growth rate, and the conversion efficiency of food to biomass. When extrinsic mortality is constant, indeterminate growth cannot maximize fitness if measured by the population growth rate or the conversion efficiency, except when mortality is low, in which case both types of animals are similar. If the fitness measure is life span reproduction, indeterminate growth maximizes fitness even with constant mortality, provided it is not very high. When mortality decreases with size, indeterminate growth maximizes fitness for almost all measures of fitness. Finally, we suggest an evolutionary link between allocation strategies and expected life span. In populations of long living species, each type of animal can establish in the population of the other. In populations of short living species, determinate growers can invade, and displace, a population of indeterminate ones. However, when the mortality risk of organisms with small size is much higher than those of large size, indeterminate growers can be superior.     

Food resource allocation patterns in lactating females in a long-term selection experiment for litter size in mice

Resource allocation patterns, as quantified by residual food intake (RFI), and the consequences for offspring development were investigated during lactation in 96 females of a mouse line selected for 104 generations for high litter size at birth (S-line) and in 87 females of a non-selected control line (C-line). Litters of 45 C-line dams (Cs) and 48 S-line dams (Ss) were standardised (s) at birth; other dams (ns) supported total number of pups born (Cns and Sns, respectively). RFI during lactation was significantly lower in Sns-dams than in C-line dams and Sns-dams. After weaning Sns-dams seemed to be able to restore the negative resource situation. Sns-pups were about 25% less mature than Cns-pups at all times. Maturity was similar for Cs- and Ss-pups from 2 d in lactation on, and about 18% and 53% higher than Cns- and Sns-pups. The pre-weaning mortality rate was significantly higher in Sns-litters (35.6 ± 2.76) than in Cns-litters (4.95 ± 2.23). The results suggest that S-line dams allocated considerably more resources to maintenance of offspring than C-line dams. This was insufficient to provide the offspring with an adequate amount of resources, resulting in reduced pup development and increased pre-weaning mortality rates.     

Optimal defense in plants: assessment of resource allocation costs

Genetic and environmental variation of functional traits within populations might be maintained by natural selection when resource allocation costs (RACs) balance trait benefits. Despite the intuitive appeal of optimization models, empirical tests have failed to support the importance of RACs for plant traits that confer resistance against pests. To address this discrepancy, we modified an early model by allowing the cost function to vary across a resource gradient as predicted for RACs and by assuming that the benefits depend on variation in the pest population for susceptibility. Instead of the intermediate defense optimum of the original model, defenses were predicted to be either high or absent, depending on resource availability and history. This result is not supported by empirical tests for ecological or evolutionary outcomes, including our own examination of glucosinolate toxins from sib-families of Boechera stricta (Brassicaceae) grown across an NPK fertilizer gradient. Although we detected an apparent cost of defense in the absence of herbivores, the cost did not increase as resources became more limiting. Also defense production did not vary across the resource gradient as predicted by the modified model. Thus, a model based on explicit expectations of RACs produced predictions that are not supported. Instead, other kinds of costs, such as ecological (indirect) costs may be more important. Alternatively, general conflicts in gene expression and antagonistic crosstalk among signaling pathways may underlie apparent costs.     

Optimal resource allocation in perennial plants: A continuous-time model

A continuous-time model, similar to W. M. Schaffer's (1983, Amer. Nat. 121, 418–431), of growth and reproduction for a perennial herb with discrete growing seasons is considered. Assuming that metabolic rates of reproductive and storage structures are equal, it was possible, through the reduction of the continuous model to a discrete one, to find the optimal allocations to the vegetative, reproductive, and reserve structures. The main feature of the optimal strategy is the existence of an optimal reserve size. The allocation to vegetative structures is, every growing season, the allocation which maximizes the total of reproductive and reserve structures at the end of the season. The relative allocation between reserve and reproductive structures is given, when reproductive success is a linear function of investment, by the fastest growth to the optimal size: no reproduction until the optimal size is reached, and, afterwards, allocation to reproduction of everything beyond what is needed to maintain size R*. Asymptotic growth to the equilibrium and cycles are possible, when reproductive success is a nonlinear function of investment (A. Pugliese, 1988, in “Biomathematics and Related Computational Problems” (L. M. Ricciardi, Ed.), Reidel, Dordrecht, to appear). It has therefore been possible to solve the “general life history problem” ( Schaffer, 1983) when growth is in general a concave function of body size. In the Discussion discrete and continuous-time models are compared; if the real dynamics is described by a continuous model of the type analyzed here, life history predictions made by analyzing the system with a discrete model are upheld.     

Dynamic resource allocation in disaster response: tradeoffs in wildfire suppression

Challenges associated with the allocation of limited resources to mitigate the impact of natural disasters inspire fundamentally new theoretical questions for dynamic decision making in coupled human and natural systems. Wildfires are one of several types of disaster phenomena, including oil spills and disease epidemics, where (1) the disaster evolves on the same timescale as the response effort, and (2) delays in response can lead to increased disaster severity and thus greater demand for resources. We introduce a minimal stochastic process to represent wildfire progression that nonetheless accurately captures the heavy tailed statistical distribution of fire sizes observed in nature. We then couple this model for fire spread to a series of response models that isolate fundamental tradeoffs both in the strength and timing of response and also in division of limited resources across multiple competing suppression efforts. Using this framework, we compute optimal strategies for decision making scenarios that arise in fire response policy.     

Contrasting age structures in cave cricket populations: patterns and significance

Abstract.

• 1 Adaptation to life in caves, as a seasonally constant environment, is expected to affect several life history traits. In this paper we investigate the age structure and phenology of twenty-seven Dolichopodu cave cricket populations from artificial and natural caves subjected to different environmental regimes and to different availability of food resources.
• 2 Morphometric data clearly revealed the occurrence of different age structures and phenology, basically indicating two contrasting patterns.
• 3 In artificial caves, which have been colonized by Dolichopoda only in historical times and where food resources and climate are chiefly dependent upon surface environment, age structure was seasonal. In contrast, in most natural caves, where cricket colonization appears to be much older and stability of both climatic parameters and trophic resources is higher, age structure was diverse and aseasonal.
• 4 However, a seasonal age structure also occurs in natural caves characterized by either recent origin or by a low temperature regime. This suggests that age structure in Dolichopoda is influenced by historical factors, stability of food resources and also by environmental stress.

     

A comparative study on resource allocation and energy efficient job scheduling strategies in large-scale parallel computing systems

In the large-scale parallel computing environment, resource allocation and energy efficient techniques are required to deliver the quality of services (QoS) and to reduce the operational cost of the system. Because the cost of the energy consumption in the environment is a dominant part of the owner’s and user’s budget. However, when considering energy efficiency, resource allocation strategies become more difficult, and QoS (i.e., queue time and response time) may violate. This paper therefore is a comparative study on job scheduling in large-scale parallel systems to: (a) minimize the queue time, response time, and energy consumption and (b) maximize the overall system utilization. We compare thirteen job scheduling policies to analyze their behavior. A set of job scheduling policies includes (a) priority-based, (b) first fit, (c) backfilling, and (d) window-based policies. All of the policies are extensively simulated and compared. For the simulation, a real data center workload comprised of 22385 jobs is used. Based on results of their performance, we incorporate energy efficiency in three policies i.e., (1) best result producer, (2) average result producer, and (3) worst result producer. We analyze the (a) queue time, (b) response time, (c) slowdown ratio, and (d) energy consumption to evaluate the policies. Moreover, we present a comprehensive workload characterization for optimizing system’s performance and for scheduler design. Major workload characteristics including (a) Narrow, (b) Wide, (c) Short, and (d) Long jobs are characterized for detailed analysis of the schedulers’ performance. This study highlights the strengths and weakness of various job scheduling polices and helps to choose an appropriate job scheduling policy in a given scenario.     

Contrasting patterns and drivers in taxonomic versus functional diversity,and community assembly of aquatic plants in subtropical lakes

Little is known about the differences in patterns and drivers between species richness (SR) and functional diversity (FD) in aquatic plants at large scales, and the underlying assembly mechanisms are not well studied. We compared SR and FD patterns of aquatic plant assemblages in 29 subtropical lakes, and detected the underlying assembly rules. Environmental drivers of SR and FD were revealed by GLM and GAM models, and the relative importance of assembly rules was determined by a null model approach. SR and FD of aquatic plants presented different patterns and drivers in this region. SR was significantly correlated with geographic, hydrological and water quality variables. We found a lower functional richness but higher functional evenness and divergence in the highland lakes. There was no significant correlation between functional richness and environmental variables. Null model analyses showed that most values of standardized effect size were located between the confidence interval, indicating a dominance of randomness. Deterministic processes such as limiting similarity and habitat filtering were also important in individual lakes. Habitat filtering plays a stronger role shaping the hydrophyte assemblages especially with the increase of elevation, area and AWLF (amplitude of water level fluctuation). Our results demonstrated that FD, in contrast to SR, were more resistant to environmental variations, and hydrology played an important role in shaping both SR and FD patterns in lake ecosystems. Furthermore, we revealed complex assembly rules and emphasized the importance of both stochastic and deterministic mechanisms in structuring aquatic plant assemblages at the regional scale.     

Biomass production and nutrient cycling in Eucalyptus short rotation energy forests in New Zealand. I: Biomass and nutrient accumulation

Accumulation of biomass and nutrients (N, P, K, Ca, Mg and Mn) was measured during the first 3-year rotation of three Eucalyptus short rotation forest species (E. botryoides, E. globulus and E. ovata) irrigated with meatworks effluent compared with no irrigation. E. globulus had the highest biomass and nutrient accumulation either irrigated with effluent or without irrigation. After 3-year growth, E. globulus stands irrigated with effluent accumulated 72 oven dry t/ha of above-ground total biomass with a total of 651 kg N, 55 kg P, 393 kg K, 251 kg Ca, 35 kg Mg and 67 kg Mn. Effluent irrigation increased the accumulation of biomass, N, P, K and Mn, but tended to reduce the leaf area index and leaf biomass, and decreased the accumulation of Ca and Mg.     

Biomass allocation in a clonal vine: Effects of intraspecific competition and nutrient availability

Biomass allocation to roots, rhizomes, runners and climbing stems (i.e. twining axis and attached leaves) was studied inCalystegia sepium L., a clonal vine. In an experiment which took 2 months, nutrient availability (low and high) and intraspecific competition (none, shoot root and both shoot and root) were manipulated. Under low nutrients the highest biomass of climbing stems was found in plants with shoot competition; the lowest was found in plants with both shoot and root competition. Total biomass under high nutrients was also greatest in plants with shoot competition. Thus, plants benefited from climbing up a shared stake rather than separate stakes. Larger plants allocated a higher proportion of biomass to runners in the nutrient-poor environment than in the nutrient-rich environment. This behaviour may increase the chance of finding nutrient-rich patches in the neighbourhood of the mother plant in a heterogeneous environment.