How can a life cycle inventory parametric model streamline life cycle assessment in the wooden pallet sector?

Purpose

This study discusses the use of parameterization within the life cycle inventory (LCI) in the wooden pallet sector, in order to test the effectiveness of LCI parametric models to calculate the environmental impacts of similar products. Starting from a single case study, the objectives of this paper are (1) to develop a LCI parametric model adaptable to a range of wooden pallets, (2) to test this model with a reference product (non-reversible pallet with four-way blocks) and (3) to determine numerical correlations between the environmental impacts and the most significant LCI parameters; these correlations can be used to improve the design of new wooden pallets.

Methods

The conceptual scheme for defining the model is based on ISO14040-44 standards. First of all, the product system was defined identifying the life cycle of a generic wood pallet, as well as its life cycle stages. A list of independent and dependent parameters was used to describe the LCI flows of a generic wooden pallet. The LCI parametric model was applied to calculate the environmental impacts of the reference product, with regard to a selection of impact categories at midpoint level (climate change, human toxicity, particulate matter formation, agricultural land occupation, fossil depletion). The model was then applied to further 11 wooden pallets belonging to the same category.

Results and discussion

The definition of a LCI parametric model based on 31 independent parameters and 21 dependent parameters streamlined the data collection process, as the information required for fulfilling the LCI are standard information about the features of the wooden pallet and its manufacturing process. The contribution analysis on the reference product revealed that the most contributing life cycle stages are wood and nails extraction and manufacturing (positive value of environmental impact) and end-of-life (avoided impact). This result is driven by two parameters: mass of wood and average distance for transport of wood. Based on the results of the application of the LCI parametric model to the identified products, one parameter-based regression and one multiple non-linear regression allowed to define a correlation between the life cycle impact assessment (LCIA) category indicators considered and the most influencing parameters.

Conclusions

The definition of LCI parametric model in the wooden pallet sector can effectively be used for calculating the environmental impacts of products with different designs, as well as for obtaining a preliminary estimation of the life cycle environmental impacts of new products.     

Cancer: A matter of life cycle?

In the last decade, the concept of "cancer stem cells" has emerged, recognised by the fact that only a small fraction of tumour cells appears to retain the stem cell properties of self-renewal and unlimited proliferation. At the same time, it is well known that cancer is an age-related disease developing at the limit of proliferating cell senescence. The apparent need to link senescence and the capacity for self-renewal has lead some authors to suggest that cancers develop from amongst senescing stem cells. However, an alternative solution has recently been proffered by Sundaram M, Guernsey DL, Rajaraman MM, Rajaraman R [Neosis: a novel type of cell division in cancer. Cancer Biol Ther 2004;3:207-18], who suggest that stemness may be a transient, cyclic property afforded by de-polyploidisation of senescing cells which have undergone polyploidisation. In this mini-review, we attempt to reconcile both of these views by the idea that cycling polyploidy intermitting senescence and rejuvenation may be features of a life cycle analogous to the life cycles of certain unicellular organisms. Furthermore, we suggest that mitotic catastrophe may represent a mechanism through which the cell can switch from the usual mitotic cell-cycle to this evolutionarily conserved life cycle. Intriguingly, some most recent data suggest that cell senescence may be reversible and that stem cells are tolerant to polyploidy caused by genotoxic stress.     

The kidney form of Trypanosoma musculi: A distinct stage in the life cycle?

Trypanosoma musculi is a parasite specific to mice, which resides in the blood and lacks intracellular stages. After immune clearance of the flagellates from the general circulation, mice are resistant to reinfection. Yet, long after parasites are no longer detected in the peripheral blood, they persist in the vasa recta of the kidneys and it has been proposed that this is an immunologically privileged site for T. musculi. This relationship provides a useful model for studies of latent or chronic infections in immune hosts. Here, Fernando Monroy and Donald Dusanic consider the immune responses of mice to T. musculi and compare characteristics of the parasites from the vasa recta (kidney forms, KFs) of mice with latent infections to trypanosomes from the peripheral blood (bloodstream forms, BSFs) of animals during active infections. They consider how KFs evade immune destruction and suggest that these sequestered parasites represent a distinct stage in the life cycle.     

Nutrition in the life cycle assessment of foods—function or impact?

Purpose

This work provides an unambiguous conceptual framework for inclusion of nutrition in Life Cycle Assessments (LCAs) of food that enables the distinction between two different roles of nutrition, namely serving as the basis of food comparisons via the functional unit and as an impact pathway that links food ingestion with human health effects.

Methods

We compare how nutritional aspects have been considered in the functional unit of published LCAs of food with the procedural requirements for ensuring comparability of the functional units. We consider the relevance of nutrient profiling models for assessing food- and diet-related health damages and benefits in the context of LCAs of food. We finally recommend a method that will enable a systematic, comparative, and holistic assessment of the marginal health effect of food products on human health.

Results and discussion

Satiety is proposed as a central attribute for comparisons of food products, while weighted measures of nutrient content are suggested to be largely misplaced as part of the functional unit. In contrast, nutritional measures have a large role to play in assessing the human health impacts of the marginal ingestion of specific food products. Such measures should enable a direct quantification of human health effect and benefits and should take advantage of robust epidemiological evidence.

Conclusions

Nutritional measures enter into both the functional unit in the form of satiety measures and into the calculation of impacts in the form of the marginal influence of the specific food item on the human health impact of the overall diet. To enhance the differentiation of health impacts at the level of individual food items, it is recommended to combine the nutrient balance indicator with the DALY Nutritional Index (DANI) in each specific dietary context.

     

A novel social life cycle assessment method for determining workers’ human development: a case study of the sugarcane biorefineries in Brazil

The International Journal of Life Cycle Assessment - The social life cycle assessment (S-LCA) methodology needs to advance in its methodological development, mainly regarding the impact assessment...     

Synthesis of life in the lab? Defining a protoliving system

The synthesis of a living system in the lab has been judged by a number of critics as partly attained by the proteinoid microsphere because of its primitive properties of metabolism, growth, and reproduction. These same critics, however, judge the organism as not alive, or as being 50 to 75 percent alive (Baltscheffsky and Jurka, 1984), owing to the absence of a nucleic acid genetic coding mechanism. The experiments in retracing evolution suggest, however, that the self-sequencing of amino acids was the evolutionary precursor of modern nucleic acid templating; the genetic memory is the molecule. The proteinoid microsphere is not a modern living system, but does represent at least a protoliving system (Fox and Dose, 1972). Berra (1990, p. 75) has commented on other difficulties in defining a protoliving system. In Berra's opinion, metabolism, reproduction, responsiveness to stimuli, and cellularity constitute or describe aliveness. These properties characterize proteinoid microspheres. A number of experiments demonstrate that amino acids in aminoacyl adenylates yield specific products, whereas nucleotides are without effect. For this and related reasons, especially the demonstrated self-sequencing of amino acids when they are warmed, resultant bio-functional properties of self-assembled microstructures, and demonstrated self-sequencing of amino acids in modern systems, the results appear to bridge from the chemical era to the biological period. All the above emerges from a departure in style of research (Young, 1984; Pauling and Zuckerkandl, 1972). The latter authors said, "It appears likely that biogenesis is the passage from a 'non-living system' existing in a large number of states to a 'living' system also existing in a large number of states."(ABSTRACT TRUNCATED AT 250 WORDS)     

Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life?

The evolution of family life requires net fitness benefits for offspring, which are commonly assumed to mainly derive from parental care. However, an additional source of benefits for offspring is often overlooked: cooperative interactions among juvenile siblings. In this study, we examined how sibling cooperation and parental care could jointly contribute to the early evolution of family life. Specifically, we tested whether the level of food transferred among siblings (sibling cooperation) in the European earwig Forficula auricularia (1) depends on the level of maternal food provisioning (parental care) and (2) is translated into offspring survival, as well as female investment into future reproduction. We show that higher levels of sibling food transfer were associated with lower levels of maternal food provisioning, possibly reflecting a compensatory relationship between sibling cooperation and maternal care. Furthermore, the level of sibling food transfer did not influence offspring survival, but was associated with negative effects on the production of the second and terminal clutch by the tending mothers. These findings indicate that sibling cooperation could mitigate the detrimental effects on offspring survival that result from being tended by low‐quality mothers. More generally, they are in line with the hypothesis that sibling cooperation is an ancestral behaviour that can be retained to compensate for insufficient levels of parental investment.     

Is there a place for culture in life cycle sustainability assessment?

Purpose

Cultures are increasingly recognised for their inherent value, yet, despite political and societal concern, culture is widely unrecognised in assessment techniques. Life cycle sustainability assessment (LCSA), a technique encompassing environmental, social and economic aspects, is growing in popularity. However, cultural values are rarely considered in LCSA. This paper reviews the meaning of culture; current efforts to include culture in environmental life cycle assessment (LCA), social LCA (S-LCA) and LCSA; and aspects to address when investigating integration of culture in LCA, S-LCA and LCSA.

Methods

A literature review was undertaken on definitions of culture, recognition of culture in policy and decision making, and how culture is incorporated into assessment techniques. The potential for integrating culture in LCSA was evaluated in terms of the potential benefits and challenges.

Results

Culture is often intangible and inaccessible, which may then lead to a lack of recognition in decision-making processes, or if it is recognised, then it is relegated as an afterthought. Explicitly including consideration of culture within LCSA will allow its representation alongside other sustainability aspects. The challenges of representing culture within LCSA include recognising when ‘culture’ should be distinguished from ‘social’; culture’s dynamic nature; the data collection process; and the diversity of cultures between stakeholders and at different scales from community through to nation. The potential benefits of representing culture within LCSA include greater resonance of LCSA results with stakeholders; a more comprehensive decision support tool which appropriately accounts for values; and an assessment technique which may help protect communities and their diversity of cultures.

Conclusions

Representing culture in LCSA is not straightforward and, to some extent, may be addressed through social indicators. However, developing LCSA to explicitly address cultural values has potential benefits. Future research should focus on opportunities for the development of (a) a culturally inclusive LCSA process and (b) additional cultural indicators and/or dimensions of existing LCSA indicators that represent cultural values.     

Evolution of the genetic machinery of the visual cycle: a novelty of the vertebrate eye?

The discovery in invertebrates of ciliary photoreceptor cells and ciliary (c)-opsins established that at least two of the three elements that characterize the vertebrate photoreceptor system were already present before vertebrate evolution. However, the origin of the third element, a series of biochemical reactions known as the "retinoid cycle," remained uncertain. To understand the evolution of the retinoid cycle, I have searched for the genetic machinery of the cycle in invertebrate genomes, with special emphasis on the cephalochordate amphioxus. Amphioxus is closely related to vertebrates, has a fairly prototypical genome, and possesses ciliary photoreceptor cells and c-opsins. Phylogenetic and structural analyses of the amphioxus sequences related with the vertebrate machinery do not support a function of amphioxus proteins in chromophore regeneration but suggest that the genetic machinery of the retinoid cycle arose in vertebrates due to duplications of ancestral nonvisual genes. These results favor the hypothesis that the retinoid cycle machinery was a functional innovation of the primitive vertebrate eye.     

What does the fruitless gene tell us about nature vs. nurture in the sex life of Drosophila?

The fruitless (fru) gene in Drosophila has been proposed to play a master regulator role in the formation of neural circuitries for male courtship behavior, which is typically considered to be an innate behavior composed of a fixed action pattern as generated by the central pattern generator. However, recent studies have shed light on experience-dependent changes and sensory-input-guided plasticity in courtship behavior. For example, enhanced male-male courtship, a fru mutant “hallmark,” disappears when fru-mutant males are raised in isolation. The fact that neural fru expression is induced by neural activities in the adult invites the supposition that Fru as a chromatin regulator mediates experience-dependent epigenetic modification, which underlies the neural and behavioral plasticity.     

Is there a gloxylate cycle in the liver of the fetal guinea pig?

Studies on the effect of the inhibitor of fatty acid oxidation (+)-octanoylcarnitine on the perfused liver of the 48–51 days fetal guinea pig indicate that the oxidation of endogenous fatty acids is a major source of carbon for the citric acid cycle and for synthesis of hexose. Consistent with this the liver can convert isocitrate to glyoxylate and glyoxylate to malate and may therefore operate a glyoxylate cycle allowing the net production of sugars from acetyl-CoA.     

Quantifying drivers of variability in life cycle greenhouse gas emissions of consumer products—a case study on laundry washing in Europe

Purpose

Variability in consumer behaviour can significantly influence the environmental performance of products and their associated impacts and this is typically not quantified in life cycle assessments. The goal of this paper is to demonstrate how consumer behaviour data can be used to understand and quantify the variability in the greenhouse gas emissions from domestic laundry washing across Europe.

Methods

Data from a pan-European consumer survey of product usage and washing habits was combined with internal company data on product format greenhouse gas (GHG) footprints and in-home measurement of energy consumption of laundry washing as well as literature data to determine the GHG footprint of laundry washing. The variability associated with four laundry detergent product formats and four wash temperature settings in washing machines were quantified on a per wash cycle basis across 23 European countries. The variability in GHG emissions associated with country electricity grid mixes was also taken into account. Monte Carlo methods were used to convert the variability in the input parameters into variability of the life cycle GHG emissions. Rank correlation analysis was used to quantify the importance of the different sources of variability.

Results and discussion

Both inter-country differences in background electricity mix as well as intra-country variation in consumer behaviour are important for determining the variability in life cycle GHG emissions of laundry detergents. The average GHG emissions related to the laundry washing process in the 23 European countries in 2014 was estimated to be 5?×?10² g CO_2?eq/wash cycle, but varied by a factor of 6.5 between countries. Intra-country variability is between a factor of 3.5 and 5.0 (90% interval). For countries with a mainly fossil-based electricity system, the dominant source of variability in GHG emissions results from consumer choices in the use of washing machines. For countries with a relatively low-carbon electricity mix, variability in life cycle GHG emissions is mainly determined by laundry product-related parameters.

Conclusions

The combination of rich data sources enabled the quantification of the variability in the life cycle GHG emissions of laundry washing which is driven by a variety of consumer choices, manufacturer choices and infrastructural differences of countries. The improved understanding of the variability needs to be balanced against the cost and challenges of assessing of consumer habits.

     

International standards with a life cycle perspective: which dimension of sustainability is addressed?

The International Journal of Life Cycle Assessment - The aim of this study is to explore the dimensions of sustainability that addressed the most within international standards and thereby present...     

Calculating biological behaviors of epigenetic states in the phage λ life cycle

The biology and behavior of bacteriophage regulation have been the focus of classical investigations of molecular control of gene expression. Both qualitative and quantitative aspects of this behavior have been systematically characterized experimentally. Complete understanding of the robustness and stability of the genetic circuitry for the lysis-lysogeny switch remains an unsolved puzzle. It is an excellent test case for our understanding of biological behavior of an integrated network based on its physical, chemical, DNA, protein, and functional properties. We have used a new approach to non-linear dynamics to formulate a new mathematical model, performed a theoretical study on the phage life cycle, and solved the crucial part of this puzzle. We find a good quantitative agreement between the theoretical calculation and published experimental observations in the protein number levels, the lysis frequency in the lysogen culture, and the lysogenization frequency for mutants of O_R. We also predict the desired robustness for the genetic switch. We believe that this is the first successful example in the quantitative calculation of robustness and stability of the phage regulatory network, one of the simplest and most well-studied regulatory systems.     

An environmental assessment of small hydropower in India: the real costs of dams’ construction under a life cycle perspective

The International Journal of Life Cycle Assessment - In the last years, India has taken a number of initiatives to boost small hydropower development based on the assumption of being a green energy...     

The evolution of life cycle complexity in aphids: Ecological optimization or historical constraint?

For decades, biologists have debated why many parasites have obligate multihost life cycles. Here, we use comparative phylogenetic analyses of aphids to evaluate the roles of ecological optimization and historical constraint in the evolution of life cycle complexity. If life cycle complexity is adaptive, it should be evolutionarily labile, that is, change in response to selection. We provide evidence that this is true in some aphids (aphidines), but not others (nonaphidines)—groups that differ in the intensity of their relationships with primary hosts. Next, we test specific mechanisms by which life cycle complexity could be adaptive or a constraint. We find that among aphidines there is a strong association between complex life cycles and polyphagy but only a weak correlation between life cycle complexity and reproductive mode. In contrast, among nonaphidines the relationship between life cycle complexity and host breadth is weak but the association between complex life cycles and sexual reproduction is strong. Thus, although the adaptiveness of life cycle complexity appears to be lineage specific, across aphids, life cycle evolution appears to be tightly linked with the evolution of other important natural history traits.