The Slowdown in Productivity Growth: Analysis of Some Contributing factors

macroeconomics,product growth

Scope Economy And Issues In Technology Management

In the 1980s, studies of technology transfer in dual-use industries have suggested a slow down in military technology spillovers to the civilian sector. This paper takes an econometric approach to measuring the bilateral spillover effect using the airframe manufacturing industry as a case study. The diffusion of technology benefits the industrial art regardless of where technological innovation is originated.  When horizontal spillover is measured as a bilateral flow of technology transfer regardless of the direction of the flow, i.e., either from military to civilian or from civilian to military, we find no evidence of a slow down, in airframe manufacturing at least, between 1961 and 1985, a period of rapid technological change in both military and commercial aircraft production. We also trace the flow of technological development in aircraft engine and measure its effect downstream on aircraft manufacturing productivity to obtain an estimate for any vertical spillover.  We find a negative relationship between upstream innovation and downstream manufacturing cost, but the linkage effect is statistically insignificant.  We suggest that further study should be pursued in a framework incorporating some concepts from organizational theory to better understand the differences in institutional structure that affect the adaptation and development of dual-use technologies, and the social setting that become necessary to achieve dual-use. &nbsp

Two- and three-input TALE-based AND logic computation in embryonic stem cells

Biological computing circuits can enhance our ability to control cellular functions and have potential applications in tissue engineering and medical treatments. Transcriptional activator-like effectors (TALEs) represent attractive components of synthetic gene regulatory circuits, as they can be designed de novo to target a given DNA sequence. We here demonstrate that TALEs can perform Boolean logic computation in mammalian cells. Using a split-intein protein-splicing strategy, we show that a functional TALE can be reconstituted from two inactive parts, thus generating two-input AND logic computation. We further demonstrate three-piece intein splicing in mammalian cells and use it to perform three-input AND computation. Using methods for random as well as targeted insertion of these relatively large genetic circuits, we show that TALE-based logic circuits are functional when integrated into the genome of mouse embryonic stem cells. Comparing construct variants in the same genomic context, we modulated the strength of the TALE-responsive promoter to improve the output of these circuits. Our work establishes split TALEs as a tool for building logic computation with the potential of controlling expression of endogenous genes or transgenes in response to a combination of cellular signals

Herbicide-resistant weeds : from research and knowledge to future needs

Synthetic herbicides have been used globally to control weeds in major field crops. This has imposed a strong selection for any trait that enables plant populations to survive and reproduce in the presence of the herbicide. Herbicide resistance in weeds must be minimized because it is a major limiting factor to food security in global agriculture. This represents a huge challenge that will require great research efforts to develop control strategies as alternatives to the dominant and almost exclusive practice of weed control by herbicides. Weed scientists, plant ecologists and evolutionary biologists should join forces and work towards an improved and more integrated understanding of resistance across all scales. This approach will likely facilitate the design of innovative solutions to the global herbicide resistance challenge

Cultivars to face climate change effects on crops and weeds: a review

International audienceAbstractClimate change is caused by the release of greenhouse gases in the atmosphere. Climate change will impact many activities, but its effects on agricultural production could be acute. Estimates of annual damages in agriculture due to temperature increase or extended periods of drought will be more costly than damages in other activities. Yield losses are caused both by direct effects of climate change on crops and by indirect effects such as increased inputs in crop production for weed control. One possible solution to counteract the effects of climate change is to seek crop cultivars that are adapted to highly variable, extreme climatic conditions and pest changes. Here we review the effects of climate change on crop cultivars and weeds. Biomass increase will augment marketable yield by 8–70 % for C3 cereals, by 20–144 % for cash and vegetable crops, and by 6–35 % for flowers. Such positive effects could however be reduced by decreasing water and nutrient availability. Rising temperature will decrease yields of temperature-sensitive crops such as maize, soybean, wheat, and cotton or specialty crops such as almonds, grapes, berries, citrus, or stone fruits. Rice, which is expected to yield better under increased CO2, will suffer serious yield losses under high temperatures. Drought stress should decrease the production of tomato, soybean, maize, and cotton. Nevertheless, reviews on C4 photosynthesis response to water stress in interaction with CO2 concentration reveal that elevated CO2 concentration lessens the deleterious effect of drought on plant productivity. C3 weeds respond more strongly than C4 types to CO2 increases through biomass and leaf area increases. The positive response of C3 crops to elevated CO2 may make C4 weeds less competitive for C3 crops, whereas C3 weeds in C4 or C3 crops could become a problem, particularly in tropical regions. Temperature increases will mainly affect the distribution of weeds, particularly C4 type, by expanding their geographical range. This will enhance further yield losses and will affect weed management systems negatively. In addition, the expansion of invasive weed species such as itchgrass, cogongrass, and witchweed facilitated by temperature increases will increase the cost for their control. Under water or nutrient shortage scenarios, an r-strategist with characteristics in the order S-C-R, such as Palmer amaranth, large crabgrass, johnsongrass, and spurges, will most probably prevail. Selection of cultivars that secure high yields under climate change but also by competing weeds is of major importance. Traits related with (a) increased root/shoot ratio, (b) vernalization periods, (c) maturity, (d) regulation of node formation and/or internode distance, (e) harvest index variations, and (f) allelopathy merit further investigation. The cumulative effects of selecting a suitable stress tolerator-competitor cultivar will be reflected in reductions of environmental pollution, lower production costs, and sustainable food production

Efficient CuInSe 2 Solar Cells Fabricated by a Novel Ink Coating Approach

A novel technique is developed for the deposition of CuInSe 2 (CIS) thin films for solar cell applications. The technique uses an ink formulation that contains Cu-In metallic pigments. A precursor layer is first formed coating this ink onto the selected substrate. The precursor film is then reacted with Se to form the CIS compound. Solar cells were fabricated on CIS absorber layers prepared by this low cost ink coating approach and devices with a conversion efficiency of over 9.0% were demonstrated. © 1998 The Electrochemical Society. S1099-0062(98)08-063-8. All rights reserved. Manuscript submitted August 14, 1998; revised manuscript received September 9, 1998. Available electronically October 1, 1998. Group I-III-VI materials are considered to be highly promising as absorber layers in high-efficiency thin film solar cell structures. In fact, the highest efficiency thin film device to date was produced on a Cu(In,Ga)Se 2 (CIGS) absorber film grown by a vacuum evaporation technique. The demonstrated conversion efficiency of 17.7% confirmed the capability of this material to yield highly efficient active devices when employed in thin film solar cell structures. High-efficiency solar cells have commonly been fabricated on CuInSe 2 (CIS) or CIGS absorbers deposited by costly vacuum deposition techniques such as coevaporation 1 and two-stage processes utilizing evaporation or sputtering. 2 There is presently great interest in the development of new lower cost processing methods for the growth of high quality CIS-type absorbers for thin film solar cell applications. Slurry or ink deposition by large area nonvacuum coating methods such as screen printing, spraying, curtain coating, roll coating, or doctor blading are attractive low-cost approaches for the growth of thin film solar cell absorbers, provided that the precursor layers obtained by these deposition techniques can be converted into high quality semiconductor films that are required for solar cell fabrication. There have been several attempts to deposit CIS absorbers using the screen printing technique. For example, Arita et al. described a method that involved (i) mixing pure Cu, In, and Se powders in the compositional ratio of 1:1:2, (ii) milling these powders in a ball mill and forming a screen printable paste, (iii) screen printing the paste on a substrate, and (iv) sintering this precursor film to form the compound layer. As can be seen from the review of previous work, the nature of the ingredients in the formulation of a paste or an ink is very important for the formation of a precursor layer which can later be converted into a high quality CIS-type compound film with properties that are desirable for solar cell applications. In this article we report a low-cost ink coating technique that was successfully employed for the deposition of CIS absorbers that could be used for the fabrication of over 9% efficient thin film solar cells. Experimental The general steps of the low-cost process used in this work for the growth of thin film CIS absorbers are schematically shown in The source of Cu and In in this work was a Cu-In alloy powder with a preselected and fixed Cu/In stoichiometric ratio. The Cu-In alloy powder was obtained by the melt atomization technique. To prepare the powder, 99.99% pure Cu and 99.99% pure In were melted under a hydrogen curtain at above 900°C. The Cu/In ratio of the melt corresponded to the targeted value range of 0.87-0.9. The melted alloy was transformed into powder in a gas atomizer employing Ar as the quenching gas. Quenched powder was collected at the bottom of the reactor and sieved to separate the particles that were smaller than 20 µm in size which were used in this work as the pigment. About 10 g of the Cu-In pigment was mixed with 23 g of water. A small amount (about 1.5 wt %) of a wetting agent and dispersant were added to this aqueous formulation. The mixture was milled in a ball mill for 42 h. The resulting metallic ink was water-thin. Particle size analysis was done on a sample of this ink using

Iatrogenic CJD due to pituitary-derived growth hormone with genetically determined incubation times of up to 40 years

Patients with iatrogenic Creutzfeldt-Jakob disease due to administration of cadaver-sourced growth hormone during childhood are still being seen in the UK 30 years after cessation of this treatment. Of the 77 patients who have developed iatrogenic Creutzfeldt-Jakob disease, 56 have been genotyped. There has been a marked change in genotype profile at polymorphic codon 129 of the prion protein gene (PRNP) from predominantly valine homozygous to a mixed picture of methionine homozygous and methionine-valine heterozygous over time. The incubation period of iatrogenic Creutzfeldt-Jakob disease is significantly different between all three genotypes. This experience is a striking contrast with that in France and the USA, which may relate to contamination of different growth hormone batches with different strains of human prions. We describe the clinical, imaging, molecular and autopsy features in 22 of 24 patients who have developed iatrogenic Creutzfeldt-Jakob disease in the UK since 2003. Mean age at onset of symptoms was 42.7 years. Gait ataxia and lower limb dysaesthesiae were the most frequent presenting symptoms. All had cerebellar signs, and the majority had myoclonus and lower limb pyramidal signs, with relatively preserved cognitive function, when first seen. There was a progressive decline in neurological and cognitive function leading to death after 5-32 (mean 14) months. Despite incubation periods approaching 40 years, the clinical duration in methionine homozygote patients appeared to be shorter than that seen in heterozygote patients. MRI showed restricted diffusion in the basal ganglia, thalamus, hippocampus, frontal and the paracentral motor cortex and cerebellar vermis. The electroencephalogram was abnormal in 15 patients and cerebrospinal fluid 14-3-3 protein was positive in half the patients. Neuropathological examination was conducted in nine patients. All but one showed synaptic prion deposition with numerous kuru type plaques in the basal ganglia, anterior frontal and parietal cortex, thalamus, basal ganglia and cerebellum. The patient with the shortest clinical duration had an atypical synaptic deposition of abnormal prion protein and no kuru plaques. Taken together, these data provide a remarkable example of the interplay between the strain of the pathogen and host prion protein genotype. Based on extensive modelling of human prion transmission barriers in transgenic mice expressing human prion protein on a mouse prion protein null background, the temporal distribution of codon 129 genotypes within the cohort of patients with iatrogenic Creutzfeldt-Jakob disease in the UK suggests that there was a point source of infecting prion contamination of growth hormone derived from a patient with Creutzfeldt-Jakob disease expressing prion protein valine 129

Targeted genetic testing for familial hypercholesterolaemia using next generation sequencing:a population-based study

Background<p></p> Familial hypercholesterolaemia (FH) is a common Mendelian condition which, untreated, results in premature coronary heart disease. An estimated 88% of FH cases are undiagnosed in the UK. We previously validated a method for FH mutation detection in a lipid clinic population using next generation sequencing (NGS), but this did not address the challenge of identifying index cases in primary care where most undiagnosed patients receive healthcare. Here, we evaluate the targeted use of NGS as a potential route to diagnosis of FH in a primary care population subset selected for hypercholesterolaemia.<p></p> Methods<p></p> We used microfluidics-based PCR amplification coupled with NGS and multiplex ligation-dependent probe amplification (MLPA) to detect mutations in LDLR, APOB and PCSK9 in three phenotypic groups within the Generation Scotland: Scottish Family Health Study including 193 individuals with high total cholesterol, 232 with moderately high total cholesterol despite cholesterol-lowering therapy, and 192 normocholesterolaemic controls.<p></p> Results<p></p> Pathogenic mutations were found in 2.1% of hypercholesterolaemic individuals, in 2.2% of subjects on cholesterol-lowering therapy and in 42% of their available first-degree relatives. In addition, variants of uncertain clinical significance (VUCS) were detected in 1.4% of the hypercholesterolaemic and cholesterol-lowering therapy groups. No pathogenic variants or VUCS were detected in controls.<p></p> Conclusions<p></p> We demonstrated that population-based genetic testing using these protocols is able to deliver definitive molecular diagnoses of FH in individuals with high cholesterol or on cholesterol-lowering therapy. The lower cost and labour associated with NGS-based testing may increase the attractiveness of a population-based approach to FH detection compared to genetic testing with conventional sequencing. This could provide one route to increasing the present low percentage of FH cases with a genetic diagnosis