Green house gas emissions due to concrete manufacture

Background, Aim and Scope The issues of environmental impacts of concrete have become important since many major infrastructure owners are now requiring environmentally sustainable design (ESD). The carbon dioxide (CO₂) emissions are often used as a rating tool to compare the environmental impact of different construction materials in ESD. Currently, the designers are forced to make estimates of CO₂ emissions for concrete in ESD based on conjecture rather than data. The aim of this study was to provide hard data collected from a number of quarries and concrete manufacturing plants so that accurate estimates can be made for concretes in ESD. Materials and Methods This paper presents the results of a research project aimed to quantify the CO₂ emissions associated with the manufacture and placement of concrete. The life cycle inventory data was collected from two coarse aggregates quarries, one fine aggregates quarry, six concrete batching plants and several other sources. The results are presented in terms of equivalent CO₂ emissions. The potential of fly ash and ground granulated blast furnace slag (GGBFS) to reduce the emissions due to concrete was investigated. A case study of a building is also presented. Results Portland cement was found to be the primary source of CO₂ emissions generated by typical commercially produced concrete mixes, being responsible for 74% to 81% of total CO₂ emissions. The next major source of CO₂ emissions in concrete was found to be coarse aggregates, being responsible for 13% to 20% of total CO₂ emissions. The majority contribution of CO₂ emissions in coarse aggregates production was found to from electricity, typically about 80%. Blasting, excavation, hauling and transport comprise less than 25%. While the explosives had very high emission factors per unit mass, they contribute very small amounts (<0.25%) to coarse aggregate production, since only small quantities are used. Production of a tonne of fine aggregates was found to generate 30% to 40% of the emissions generated by the production of a tonne of coarse aggregates. Fine aggregates generate less equivalent CO₂ since they are only graded, not crushed. Diesel and electricity were found to contribute almost equally to the CO₂ emissions due to fine aggregates production. Emission contributions due to admixtures were found to be negligible. Concrete batching, transport and placement activities were all found to contribute very small amounts of CO₂ to total concrete emissions. Discussion The CO₂ emissions generated by typical normal strength concrete mixes using Portland cement as the only binder were found to range between 0.29 and 0.32 t CO₂-e/m³. GGBFS was found to be capable of reducing concrete CO₂ emissions by 22% in typical concrete mixes. Fly ash was found to be capable of reducing concrete CO₂ emissions by 13% to 15% in typical concrete mixes. Conclusions The results presented are based on typical concrete manufacturing and placement methods in Australia. The data presented in this paper can be utilized to compare green house gas emissions due to concrete with those associated with alternative construction materials. Recommendations and Perspectives The various rating schemes used to compare alternative construction materials should use models such as the one presented in this paper, based on hard data so that reliable comparisons can be made. A case study is presented in this paper demonstrating how the results may be utilized. ESS-Submission Editor: Dr. Stefanie Hellweg (stefanie.hellweg@ifu.baug.ethz.ch)     

Cultivation and utilisation of red seaweeds in the Western Indian Ocean (WIO) Region

Seaweed farming in the Western Indian Ocean (WIO) Region is carried out in a number of countries, most of them farming Eucheuma denticulatum, Kappaphycus alvarezii and Kappaphycus striatum. These species are farmed mostly in Tanzania with limited production in Madagascar, Mozambique and Kenya; current production (2012) stands at 15,966 t (dry weight) year^?1 of Eucheuma and Kappaphycus, valued at US$ 4.2 million with 95 % of this tonnage coming from Tanzania. Other countries in the region have limited or no seaweed production owing to problems of epiphytes, ice ice and markets. The problem of epiphytes coupled with ice ice that WIO countries are facing causes die-off of Kappaphycus which is the preferred species in foreign markets for its thicker gel, kappa carrageenan (vs. the weaker iota carrageenan from Eucheuma). New efforts are put to curb these problems including moving seaweed farms to deeper waters and cultivation trials of other carrageenophytes as well as agar-producing species, agarophytes. Research work has been initiated to evaluate Gracilaria and Hypnea farming and processing in Tanzania, the Republic of Mauritius and Mayotte. Gracilaria farming is at experimental stages as a biofilter of fishpond effluents and as potential species for the production of agar with growth rates of 1.5–1.9 % day^?1. Hypnea farming is only being initiated in Mauritius and Mayotte at present. Other innovations including value addition by making various seaweed products and encouraging the consumption of seaweed as food at least in Tanzania and Mauritius are increasing further the importance of the seaweed farming and processing industry in the WIO Region.     

Annexin A1 modulates macula densa function by inhibiting cyclooxygenase 2

Annexin A1 (ANXA1) exerts anti-inflammatory effects through multiple mechanisms including inhibition of prostaglandin synthesis. Once secreted, ANXA1 can bind to G protein-coupled formyl peptide receptors (Fpr) and activate diverse cellular signaling pathways. ANXA1 is known to be expressed in cells of the juxtaglomerular apparatus, but its relation to the expression of cyclooxygenase 2 (COX-2) in thick ascending limb and macula densa cells has not been elucidated. We hypothesized that ANXA1 regulates the biosynthesis of COX-2. ANXA1 abundance in rat kidney macula densa was extensively colocalized with COX-2 (95%). Furosemide, an established stimulus for COX-2 induction, caused enhanced expression of both ANXA1 and COX-2 with maintained colocalization (99%). In ANXA1-deficient mice, COX-2-positive cells were more numerous than in control mice (+107%; normalized to glomerular number; P < 0.05) and renin expression was increased (+566%; normalized to glomerular number; P < 0.05). Cultured macula densa cells transfected with full-length rat ANXA1 revealed downregulation of COX-2 mRNA (-59%; P < 0.05). Similarly, treatment with dexamethasone suppressed COX-2 mRNA in the cells (-49%; P < 0.05), while inducing ANXA1 mRNA (+56%; P < 0.05) and ANXA1 protein secretion. Inhibition of the ANXA-1 receptor Fpr1 with cyclosporin H blunted the effect of dexamethasone on COX-2 expression. These data show that ANXA1 exerts an inhibitory effect on COX-2 expression in the macula densa. ANXA1 may be a novel intrinsic modulator of renal juxtaglomerular regulation by inhibition of PGE(2) synthesis.     

Pediatricians’ Own Weight: Self‐perception,Misclassification, and Ease of Counseling

Objectives: Pediatricians underdiagnose overweight and feel ineffective at counseling. Given the relationship between physicians’ health and health habits and counseling behaviors, we sought to determine the 1) percentage of pediatricians who are overweight; 2) accuracy of pediatricians’ own weight status classification; and 3) relationship between weight self‐perception and perceived ease of obesity counseling. Research Methods and Procedures: This study was a cross‐sectional, mail survey of North Carolina pediatricians that queried about their weight status and ease of counseling. Accuracy of pediatricians’ self‐classification of weight status was compared with BMIs derived from self‐reported height and weight. Using logistic regression, controlling for potential confounding variables, we examined the association between weight perception and ease of counseling. Results: The unadjusted response rate was 62%, and the adjusted response rate was 71% (n = 355). Nearly one‐half (49%) of overweight pediatricians did not identify themselves as such. Men had greater adjusted odds of misclassifying overweight than women [odds ratio (OR), 3.61; 95% confidence interval (CI) = 1.81, 7.21]. Self‐classified “thin” pediatricians had nearly six times the odds of reporting more counseling difficulty as a result of their weight than “average” weight pediatricians (OR = 5.69; 95% CI = 2.30, 14.1), and self‐identified “overweight” pediatricians reported nearly four times as great counseling difficulty as “average” weight physicians (OR = 3.84; 95% CI = 1.11, 13.3), after adjustment for self‐reported BMI weight status and other potential confounders. Discussion: The roles that physician weight misclassification and self‐perception potentially play in influencing rates of obesity counseling warrant further research.     

一种大规模筛选单克隆及提取质粒的改进方法

利用α-互补(X-gal IPTG)从cDNA库中筛选特异克隆,以此去除含有未插入片段和插入片段小的克隆。运用展库的方法,通过辅助噬菌体对库中多个载体的切割,将载体以质粒的形式转化到大肠杆菌中;同时对质粒DNA碱裂解提取方法做了改进,建立了一种简单实用的大量提取质粒DNA的方法。该方法利用特定的蛋白质吸附膜吸附提取过程中的蛋白质,从而去除了使用酚-氯仿抽提蛋白质的复杂过程,减少了质粒DNA的损失,是一次性获得大规模质粒DNA的有效方法。获取的质粒DNA样品在纯度和浓度上都可以满足测序、PCR及Southern杂交等分子生物学实验的要求。     

Human Borna disease virus infection in Australia: serological markers of infection in multi-transfused patients

Borna disease virus (BDV) causes neurological disease in horses, however, there is no consensus as to the extent or significance of human infection. BDV antigen levels in plasma (BDVpAg) and anti-BDV were measured by ELISAs. Confirmation was by Western blot (WB), immunofluorescence assay (IFA) or BDV-peptide-epitope ELISA. For 42 volunteers psychiatrically-defined as non-depressed (82 samples) neither BDVpAg nor anti-BDV was detected. For 104 patients with diagnosed depression (290 samples) 1 was BDVpAg positive and 5 anti-BDV positive, one epitope-e8 positive and 4 IFA positive, with 96% concordance for repeat samples. No BDVpAg was detected in 214 pregnant women, 2 were anti-BDV positive, one WB-confirmed (p24/p40). For 219 donors 2 were BDVpAg positive with anti-BDV detected in 5 (2.3%) one IFA 1:10, another IFA 1:40/epitope-e8 positive. In multitransfused patients, 3/168 were BDV pAg positive, with 14/168 anti-BDV positive, 1 epitope-e8 positive, 2 WB positive and 1 IFA 1:10. In BDVpAg positive multi-transfused patients there was an elevated risk of transaminitis. In one case, a patient BDV-negative prior to transfusion was BDVpAg positive for several months posttransfusion (associated with transaminitis). These data provide serological evidence, supported by confirmatory assays and repeat-sample concordance, of BDV infection in Australia, particularly in multi-transfused patients.     

Distribution and symptoms of epiphyte infection in major carrageenophyte-producing farms

High density commercial farming of carrageenophyte Kappaphycus alvarezii is often plagued with “ice-ice” disease and epiphyte infection, which eventually leads to reduced production and in some cases collapse of crop. Epiphyte outbreak has been occurring regularly in major carrageenophyte farms in the Philippines, Indonesia, Malaysia and Tanzania. Infected materials from these countries were studied to establish baseline information on the epiphyte’s identity, density, symptoms and secondary infection on the host seaweed. The causative organism was identified as Neosiphonia apiculata (Hollenberg) Masuda et Kogame, based on its morphological features. Epiphyte density on host seaweed materials decreased in the following order: the Philippines (88.5 epi cm⁻²), Tanzania (69.0 epi cm⁻²), Indonesia (56.5 epi cm⁻²) and Malaysia (42.0 epi cm⁻²). Initial symptoms were the presence of tiny black spots, indicating the embedded tetrasporeling in seaweed cortex layer. Vegetative form emerged after 2 weeks measuring less than 0.5 mm in length with a density of less than 25.0 epi cm⁻². Upon maturation, infected seaweed takes on a “hairy” appearance with “goose-bumps” like cortical swellings. The epiphyte appears as a solitary plant with multiple secondary rhizoids or as multiple epiphytes appearing from a single cortical opening. At the end of infection, the epiphytes left dark pits on the cortical swelling, and the carrageenophytes are infected by opportunistic bacteria. Bacterial enumeration of healthy and infected seaweed materials showed an increase of more than 300% in total bacterial count on infected materials dominated by Alteromonas sp., Flavobacterium sp. and Vibrio sp.     

Open water zooplankton communities in North African wetland lakes: the CASSARINA Project

Zooplankton (Copepoda, Cladocera, Ostracoda, Rotifera and Diptera larvae) in nine North African lakes was collected from open water areas over twenty months during 1997/99. The results were used to monitor changes in the pelagic micro-invertebrate fauna of these sites with the purpose of exploring diversity structure and regional species occurrences.The studied sites formed three distinct groups based on hydrology and water quality criteria: (i) acid water with no marine connection (Megene Chitane); (ii) alkaline freshwater/brackish with no marine connection (Merja Sidi Bou Rhaba and Merja Bokka); (iii) freshwater/brackish with marine connection (Merja Zerga, Lac de Korba, Garaet El Ichkeul and three Nile Delta lakes). However, cluster analysis of the zooplankton data alone indicated four groups with Korba being separated because of its prevalence of species tolerant of summer hypersalinity.The total regional zooplanktonic species richness found was 88 taxa and these were characterized by species tolerant of widely fluctuating environmental conditions. However, some recorded species were very rare for North African freshwaters (e.g. Alonella excisa, Leydigia quadrangularis and, Ilyocryptus sordidus) and generally indicate favourable environmental conditions of low salinity and temperature. The sites influenced by marine waters generally exhibited slightly lower numbers of species but which generally demonstrate cosmopolitan distributions. Distinct seasonal patterns in species distributions were more similar to those observed in European lakes rather than to those of lower latitudes sites.Zooplankton play a key role in maintaining aquatic ecosystem quality in the North African study lakes and the community distributions described for the late 20th century help set biodiversity base-line data for future studies. If the remaining wetland lakes in this region are to persist as important resources during the 21st century, they will need to be managed in a way that ensures that aquatic diversity is maintained.     

Radiometrically determined dates and sedimentation rates for recent sediments in nine North African wetland lakes (the CASSARINA Project)

Sediment cores were collected from nine wetland lakes in Morocco, Tunisia and Egypt for the CASSARINA project investigating environmental change in Northern African wetlands. The cores were dated radiometrically by using natural (²¹⁰Pb) and artificial (¹³⁷Cs and ²⁴¹Am) radionuclides. At sites in Morocco and Tunisia with mean annual rainfall totals ranging from 500–1000 mm yr^–1, fallout records were generally satisfactory and it was possible to develop independent sediment chronologies based on the radiometric data alone. At the Egyptian sites, rainfall was less than 200 mm yr^–1 and fallout records were much less distinct. At these sites the radiometric data could only be used to give an indication of mean sedimentation rates during the past 30–40 years. By using a combination of fallout radionuclide, pollen, and macrofossil stratigraphic records it was however possible to determine a credible sediment chronology spanning the major part of the 20th century. Applying this chronology to records of spheroidal carbonaceous particles (SCP) from the same sediment cores, the onset of significant levels of atmospheric pollution in the Nile Delta is dated in all three cores to the mid 1950s. Results from a number of lakes (Sidi Bou Rhaba, Ichkeul and Korba) revealed high and accelerating siltation rates, threatening their continued existence beyond the next few decades. In contrast, sedimentation rates at all three Nile Delta sites appear to have declined in recent decades, most probably due to the impact of the Nile barrages.