Scale of production and choice of technique in the engineering industries in developing countries

This article examines the relationship between scale of production, optimal choice of technique and costs for three engineering industries: nuts and bolts, iron founding and machine tools. In all three industries costs of production fell as the scale of output increased. This was associated with switches of technique and the spread of fixed costs over a larger number of units. The capital-output ratio fell and labour productivity increased with increases in scale while, in most cases, the capital-labour ratio increased. The implications of these findings are briefly discussed.

Influence of preparation conditions on the characteristics of activated carbons produced in laboratory and pilot scale systems

The central theme of this investigation is to evaluate the feasibility of using bituminous coal as a precursor material for the production of chars and activated carbons using physical and chemical activation processes. The chemical activation process was accomplished by impregnating the raw materials with different dehydrating agents in different ratios and concentrations, prior to heat treatment (ZnCl2, KCl, KOH, NaOH and Fe2(SO4)3·xH2O). Steam activation of the precursor material was adopted for the preparation of activated carbon using physical activation technology. Different types of bituminous coal; namely, contaminated Columbian (contaminated with pet. coke), pure Columbian, Venezuelan and New Zealand bituminous coal were used in the production processes. BET surface area, micropore area, pore size distribution and total pore volume of the chars and activated carbons were determined from N2 adsorption/desorption isotherm, measured at 77 K. Charring conditions, charring temperature of 800 °C and charring time of 4 h, proved to be the optimum conditions for preparing chars. Contaminated Columbian were found to be the best precursor material for the production of char with reasonable physical characteristics (surface area = 138.1 m2 g-1 and total pore volume of 8.656 × 10-0.2 cm3 g-1). An improvement in the physical characteristics of the activated carbons was obtained upon the treatment of coal with dehydrating agents. Contaminated Columbian treated with 10 wt% ZnCl2 displayed the highest surface area and total pore volume (surface area = 231.5 m2 g-1 and total pore volume = 0.1227 cm3 g-1) with well-developed microporisity (micropore area = 92.3 m2 g-1). Venezuelan bituminous coal using the steam activation process was successful in producing activated carbon with superior physical characteristics (surface area = 863.50 m2 g-1, total pore volume = 0.469 cm3 g-1 and micropore surface area = 783.58 m2 g-1).

Production and characterization of specific antibodies for evaluation of glycated insulin in plasma and biological tissues

Previous studies have shown that glycation of insulin occurs in pancreatic beta -cells under conditions of hyperglycaemia and that the site of glycation is the N-terminal Phe(1) of the insulin B-chain. To enable evaluation of glycated insulin in diabetes, specific antibodies were raised in rabbits and guinea-pigs by using two synthetic peptides (A: Phe-Val-Asn-Gln-His-Leu-Cys-Tyr, and B: Phe-Val-Asn-Gln-His-Leu-Tyr-Lys) modified by N-terminal glycation and corresponding closely to the N-terminal sequence of the glycated human insulin B-chain. For immunization, the glycated peptides were conjugated either to keyhole limper haemocyanin or ovalbumin using glutaraldehyde, m-maleimidobenzoyl-N-hydroxysuccinimide ester or 1-ethyl-3-(3-dimethylamino propyl) carbodiimide hydrochloride. Antibody titration curves, obtained using I-125-tyrosylated tracer prepared from glycated peptide A, revealed high-titre antisera in five groups of animals immunized for 8-28 weeks. The highest titres were observed in rabbits and guinea-pigs immunized with peptide B coupled to ovalbumin using glutaraldehyde. Under radioimmunoassay conditions, these antisera exhibited effective dose (median) (ED50) values for glycated insulin of 0.3-15 ng/ml and 0.9-2.5 ng/ml respectively, with negligible cross-reactivity against insulin or other islet peptides. The degree of cross-reaction with glycated proinsulin was approximately 50%. Glycated insulin in plasma of control and hydrocortisone-treated diabetic rats measured using rabbit 3 antiserum (1:10 000 dilution; sensitivity

Spatial patterns and autocorrelation in the response of microarthropods to soil pollutants: The example of oribatid mites in an abandoned mining and smelting area

Although exogenous factors such as pollutants can act on endogenous drivers (e.g. dispersion) of populations and create spatially autocorrelated distributions, most statistical techniques assume independence of error terms. As there are no studies on metal soil pollutants and microarthropods that explicitly analyse this key issue, we completed a field study of the correlation between Oribatida and metal concentrations in litter, organic matter and soil in an attempt to account for spatial patterns of both metals and mites. The 50-m wide study area had homogenous macroscopic features, steep Pb and Cu gradients and high levels of Zn and Cd. Spatial models failed to detect metal-oribatid relationships because the observed latitudinal and longitudinal gradients in oribatid assemblages were independent of the collinear gradients in the concentration of metals. It is therefore hypothesised that other spatially variable factors (e.g. fungi, reduced macrofauna) affect oribatid assemblages, which may be influenced by metals only indirectly. (C) 2009 Elsevier Ltd. All rights reserved.

Distillable entanglement and area laws in spin and harmonic-oscillator systems

We address the presence of nondistillable (bound) entanglement in natural many-body systems. In particular, we consider standard harmonic and spin-1/2 chains, at thermal equilibrium and characterized by few interaction parameters. The existence of bound entanglement is addressed by calculating explicitly the negativity of entanglement for different partitions. This allows us to individuate a range of temperatures for which no entanglement can be distilled by means of local operations, despite the system being globally entangled. We discuss how the appearance of bound entanglement can be linked to entanglement-area laws, typical of these systems. Various types of interactions are explored, showing that the presence of bound entanglement is an intrinsic feature of these systems. In the harmonic case, we analytically prove that thermal bound entanglement persists for systems composed by an arbitrary number of particles. Our results strongly suggest the existence of bound entangled states in the macroscopic limit also for spin-1/2 systems.

Comparison of 5% versus 15% sucrose intakes as part of a eucaloric diet in overweight and obese subjects:effects on insulin sensitivity, glucose metabolism, vascular compliance, body composition and lipid profile. A randomised controlled trial

AIMS: The effect of dietary sucrose on insulin resistance and the pathogenesis of diabetes and vascular disease is unclear. We assessed the effect of 5% versus 15% sucrose intakes as part of a weight maintaining, eucaloric diet in overweight/obese subjects.

METHODS: Thirteen subjects took part in a randomised controlled crossover study (M:F 9:4, median age 46 years, range 37-56 years, BMI 31.7±0.9 kg/m(2)). Subjects completed two 6 week dietary periods separated by 4 week washout. Diets were designed to have identical macronutrient profile. Insulin action was assessed using a two-step hyperinsulinaemic euglycaemic clamp; glucose tolerance, vascular compliance, body composition and lipid profiles were also assessed.

RESULTS: There was no change in weight or body composition between diets. There was no difference in peripheral glucose utilization or suppression of endogenous glucose production. Fasting glucose was significantly lower after the 5% diet. There was no demonstrated effect on lipid profiles, blood pressure or vascular compliance.

CONCLUSION: A low-sucrose diet had no beneficial effect on insulin resistance as measured by the euglycaemic glucose clamp. However, reductions in fasting glucose, one hour insulin and insulin area under the curve with the low sucrose diet on glucose tolerance testing may indicate a beneficial effect and further work is required to determine if this is the case. Clinical Trial Registration number ISRCTN50808730.

The NOTCH signaling pathway in normal and malignant blood cell production

The NOTCH pathway is an evolutionarily conserved signalling network, which is fundamental in regulating developmental processes in invertebrates and vertebrates (Gazave et al. in BMC Evol Biol 9:249, 2009). It regulates self-renewal (Butler et al. in Cell Stem Cell 6:251–264, 2010), differentiation (Auderset et al. in Curr Top Microbiol Immunol 360:115–134, 2012), proliferation (VanDussen et al. in Development 139:488–497, 2012) and apoptosis (Cao et al. in APMIS 120:441–450, 2012) of diverse cell types at various stages of their development. NOTCH signalling governs cell-cell interactions and the outcome of such responses is highly context specific. This makes it impossible to generalize about NOTCH functions as it stimulates survival and differentiation of certain cell types, whereas inhibiting these processes in others (Meier-Stiegen et al. in PLoS One 5:e11481, 2010). NOTCH was first identified in 1914 in Drosophila and was named after the indentations (notches) present in the wings of the mutant flies (Bigas et al. in Int J Dev Biol 54:1175–1188, 2010). Homologs of NOTCH in vertebrates were initially identified in Xenopus (Coffman et al. in Science 249:1438–1441, 1990) and in humans NOTCH was first identified in T-Acute Lymphoblastic Leukaemia (T-ALL) (Ellisen et al. in Cell 66:649–61, 1991). NOTCH signalling is integral in neurogenesis (Mead and Yutzey in Dev Dyn 241:376–389, 2012), myogenesis (Schuster-Gossler et al. in Proc Natl Acad Sci U S A 104:537–542, 2007), haematopoiesis (Bigas et al. in Int J Dev Biol 54:1175–1188, 2010), oogenesis (Xu and Gridley in Genet Res Int 2012:648207, 2012), differentiation of intestinal cells (Okamoto et al. in Am J Physiol Gastrointest Liver Physiol 296:G23–35, 2009) and pancreatic cells (Apelqvist et al. in Nature 400:877–881, 1999). The current review will focus on NOTCH signalling in normal and malignant blood cell production or haematopoiesis.

Holocene landscape intervention and plant food production strategies in island and mainland Southeast Asia

In the areas adjacent to the drowned Pleistocene continent of Sunda – present-day Mainland and Island SE Asia – the Austronesian Hypothesis of a diaspora of rice cultivators from Taiwan ∼4200 years ago has often been linked with the start of farming. Mounting evidence suggests that these developments should not be conflated and that alternative explanations should be considered, including indigenous inception of complex patterns of plant food production and early exchange of plants, animals, technology and genes. We review evidence for widespread forest disturbance in the Early Holocene which may accompany the beginnings of complex food-production. Although often insubstantial, evidence for incipient and developing management of rainforest vegetation and of developing complex relationships with plants is present, and early enough to suggest that during the Early to mid-Holocene this vast region was marked by different approaches to plant food production. The trajectory of the increasingly complex relationships between people and their food organisms was strongly locally contingent and in many cases did not result in the development of agricultural systems that were recognisable as such at the time of early European encounters. Diverse resource management economies in the Sunda and neighbouring regions appear to have accompanied rather than replaced a reliance on hunting and gathering. This, together with evidence for Early Holocene interaction between these neighbours, gives cause for us to question some authors continued adherence to a singular narrative of the Austronesian Hypothesis and the ‘Neolithisation’ of this part of the world. It also leads us to suggest that the forests of this vast region are, to an extent, a cultural artefact.