Comparative life cycle assessment and life cycle costing of lodging in the Himalaya

Purpose

The main aim of the study is to assess the environmental and economic impacts of the lodging sector located in the Himalayan region of Nepal, from a life cycle perspective. The assessment should support decision making in technology and material selection for minimal environmental and economic burden in future construction projects.

Methods

The study consists of the life cycle assessment and life cycle costing of lodging in three building types: traditional, semi-modern and modern. The life cycle stages under analysis include raw material acquisition, manufacturing, construction, use, maintenance and material replacement. The study includes a sensitivity analysis focusing on the lifespan of buildings, occupancy rate and discount and inflation rates. The functional unit was formulated as the ‘Lodging of one additional guest per night’, and the time horizon is 50 years of building lifespan. Both primary and secondary data were used in the life cycle inventory.

Results and discussion

The modern building has the highest global warming potential (kg CO_2-eq) as well as higher costs over 50 years of building lifespan. The results show that the use stage is responsible for the largest share of environmental impacts and costs, which are related to energy use for different household activities. The use of commercial materials in the modern building, which have to be transported mostly from the capital in the buildings, makes the higher GWP in the construction and replacement stages. Furthermore, a breakdown of the building components shows that the roof and wall of the building are the largest contributors to the production-related environmental impact.

Conclusions

The findings suggest that the main improvement opportunities in the lodging sector lie in the reduction of impacts on the use stage and in the choice of materials for wall and roof.

     

Habitat uncertainty explains variation in offspring provisioning strategies in a temporary pond crustacean

Along with the development of nanotechnology, an increase in production and application of nanosized magnetite (Fe₃O₄) is expected. Though magnetite is considered relatively safe, information concerning potential hazards of synthetic magnetite nanoparticles with unique physico-chemical characteristics to aquatic organisms is still limited. In this study, we evaluated the toxicity of nanosized (27.2 ± 9.8 nm) and bulk (144.2 ± 67.7 nm) magnetite particles to different life stages of the aquatic crustacean Daphnia magna. In addition, phytotoxicity of the magnetite was evaluated using duckweed Lemna minor. The study did not reveal any statistically significant differences between the biological effects of nanosized and bulk magnetite particles. Both forms of magnetite induced very low toxicity (EC50 > 100 ppm) to D. magna and L. minor in the standard acute assays. However, it was demonstrated that at acutely subtoxic magnetite concentrations (10 and 100 ppm), the number of neonates hatched from D. magna ephippia was decreased. Moreover, short-term (48 h) exposure of neonate daphnids to these concentrations may significantly affect the long-term survival and reproductive potential of daphnids. These results indicate that substantial contamination of aquatic ecosystems by magnetite may disrupt the stability of cladoceran populations.     

Cdc20 and Cks direct the spindle checkpoint-independent destruction of cyclin A

Successful mitosis requires the right protein be degraded at the right time. Central to this is the spindle checkpoint that prevents the destruction of securin and cyclin B1 when there are improperly attached chromosomes. The principal target of the checkpoint is Cdc20, which activates the anaphase-promoting complex/cyclosome (APC/C). A Drosophila Cdc20/fizzy mutant arrests in mitosis with high levels of cyclins A and B, but paradoxically the spindle checkpoint does not stabilize cyclin A. Here, we investigated this paradox and found that Cdc20 is rate limiting for cyclin A destruction. Indeed, Cdc20 binds efficiently to cyclin A before and in mitosis, and this complex has little associated Mad2. Furthermore, the cyclin A complex must bind to a Cks protein to be degraded independently of the checkpoint. Thus, we identify a crucial role for the Cks proteins in mitosis and one mechanism by which the APC/C can target substrates independently of the spindle checkpoint.     

Modelling pink-footed goose (Anser brachyrhynchus) wintering distributions for the year 2050: potential effects of land-use change in Europe

Feeding on farmland by overwintering populations of pink-footed geese ( Anser brachyrhynchus ) conflicts with agricultural interests in Northern Europe. In order to forecast the potential future of this conflict, we used generalized linear models to relate the presence and absence of pink-footed geese to variables describing the contemporary landscape, and predicted their future distributions in relation to two land-use scenarios for the year 2050. One future scenario represented a global, economically orientated world (A1) and the other represented a regional, environmentally concerned world (B2). The probability of goose occurrence increased within cropland and grassland, and could be explained by their proximity to coast, elevation, and the degree of habitat closure. Predictions to future scenarios revealed noticeable shifts in the suitability of goose habitat evident at the local and regional scale in response to future shifts in land use. In particular, as grasslands and croplands give way to unsuitable land-use types (e.g. woody biofuel crops, increased urbanization, and forest) under both future scenarios, our models predicted a decrease in habitat suitability for geese. If coupled with continued goose population expansion, we expect that the agricultural conflict will intensify under the A1 and particularly the B2 scenarios.     

Effects of nutrients and fish on periphyton and plant biomass across a European latitudinal gradient

Replicated, factorial mesocosm experiments were conducted across Europe to study the effects of nutrient enrichment and fish density on macrophytes and on periphyton chlorophyll a (chl-a) with regard to latitude. Periphyton chl-a densities and plant decline were significantly related to nutrient loading in all countries. Fish effects were significant in a few sites only, mostly because of their contribution to the nutrient pool. A saturation-response type curve in periphyton chl-a with nutrients was found, and northern lakes achieved higher densities than southern lakes. Nutrient concentration and phytoplankton chl-a necessary for a 50% plant reduction followed a latitudinal gradient. Total phosphorus values for 50% plant disappearance were similar from Sweden (0.27 mg L⁻¹) to northern Spain (0.35 mg L⁻¹), but with a sharp increase in southern Spain (0.9 mg L⁻¹). Planktonic chl-a values for 50% plant reduction increased monotonically from Sweden (30 μg L⁻¹) to València (150 μg L⁻¹). Longer plant growing-season, higher light intensities and temperature, and strong water-level fluctuations characteristic of southern latitudes can lead to greater persistence of macrophyte biomass at higher turbidities and nutrient concentration than in northern lakes. Results support the evidence that latitudinal differences in the functioning of shallow lakes should be considered in lake management and conservation policies.     

Highly efficient depletion strategy for the two most abundant erythrocyte soluble proteins improves proteome coverage dramatically

In-depth human erythrocyte proteome studies are severely hampered by the presence of hemoglobin and carbonic anhydrase-1, which account for more than 98% of the total erythrocyte soluble protein content. We developed a specific depletion approach that resulted in a drastic increase in the number of identified proteins. This depletion technique is valuable for proteome studies of human erythrocyte disorders with unknown etiology and of tissue samples that contain blood.     

CodY of Streptococcus pneumoniae: link between nutritional gene regulation and colonization

CodY is a nutritional regulator mainly involved in amino acid metabolism. It has been extensively studied in Bacillus subtilis and Lactococcus lactis. We investigated the role of CodY in gene regulation and virulence of the human pathogen Streptococcus pneumoniae. We constructed a codY mutant and examined the effect on gene and protein expression by microarray and two-dimensional differential gel electrophoresis analysis. The pneumococcal CodY regulon was found to consist predominantly of genes involved in amino acid metabolism but also several other cellular processes, such as carbon metabolism and iron uptake. By means of electrophoretic mobility shift assays and DNA footprinting, we showed that most of the targets identified are under the direct control of CodY. By mutating DNA predicted to represent the CodY box based on the L. lactis consensus, we demonstrated that this sequence is indeed required for in vitro DNA binding to target promoters. Similar to L. lactis, DNA binding of CodY was enhanced in the presence of branched-chain amino acids, but not by GTP. We observed in experimental mouse models that codY is transcribed in the murine nasopharynx and lungs and is specifically required for colonization. This finding was underscored by the diminished ability of the codY mutant to adhere to nasopharyngeal cells in vitro. Furthermore, we found that pcpA, activated by CodY, is required for adherence to nasopharyngeal cells, suggesting a direct link between nutritional regulation and adherence. In conclusion, pneumococcal CodY predominantly regulates genes involved in amino acid metabolism and contributes to the early stages of infection, i.e., colonization of the nasopharynx.     

Connexin Channels, Connexin Mimetic Peptides and ATP Release

Connexin hemichannels, that is, half gap junction channels (not connecting cells), have been implicated in the release of various messengers such as ATP and glutamate. We used connexin mimetic peptides, which are, small peptides mimicking a sequence on the connexin subunit, to investigate hemichannel functioning in endothelial cell lines. Short exposure (30 min) to synthetic peptides mimicking a sequence on the first or second extracellular loop of the connexin subunit strongly supressed ATP release and dye uptake triggered by either intracellular InsP₃ elevation or exposure to zero extracellular calcium, while gap junctional coupling was not affected under these conditions. The effect was dependent on the expression of connexin-43 in the cells. Connexin mimetic peptides thus appear to be interesting tools to distinguish connexin hemichannel from gap junction channel functioning. In addition, they are well suited to further explore the role of connexins in cellular release or uptake processes, to investigate hemichannel gating and to reveal new unknown functions of the large conductance hemichannel pathway between the cell and its environment. Work performed up to now with these peptides should be re-interpreted in terms of these new findings.