Contribution Of Structural Change Research Articles

Molecular determinants for cold adaptation in an Antarctic Na+/K+-ATPase

Enzymes from ectotherms living in chronically cold environments have evolved structural innovations to overcome the effects of temperature on catalysis. Cold adaptation of soluble enzymes is driven by changes within their primary structure or the aqueous milieu. For membrane-embedded enzymes, like the Na+/K+-ATPase, the situation is different because changes to the lipid bilayer in which they operate may also be relevant. Although much attention has been focused on thermal adaptation within lipid bilayers, relatively little is known about the contribution of structural changes within membrane-bound enzymes themselves. The identification of specific mutations that confer temperature compensation is complicated by the presence of neutral mutations, which can be more numerous. In the present study, we identified specific amino acids in a Na+/K+-ATPase from an Antarctic octopus that underlie cold resistance. Our approach was to generate chimeras between an Antarctic clone and a temperate ortholog and then study their temperature sensitivities in Xenopus oocytes using an electrophysiological approach. We identified 12 positions in the Antarctic Na+/K+-ATPase that, when transferred to the temperate ortholog, were sufficient to confer cold tolerance. Furthermore, although all 12 Antarctic mutations were required for the full phenotype, a single leucine in the third transmembrane segment (M3) imparted most of it. Mutations that confer cold resistance are mostly in transmembrane segments, at positions that face the lipid bilayer. We propose that the interface between a transmembrane enzyme and the lipid bilayer is a critical determinant of temperature sensitivity and, accordingly, has been a prime evolutionary target for thermal adaptation.

Mechanical and morphological properties of poly(vinyl chloride) and linear low‐density polyethylene polymer blends

AbstractIn this article, nonpolar polyethylene with polar poly(vinyl chloride) is considered as a polymer–polymer mixture. Direct mixing of poly(vinyl chloride) and polyolefins leads to the formation of incompatible mixtures that have weak complex properties. To form this mixture, chlorinated polyethylene and a copolymer of polyvinyl chloride with polyethylene were used as compatibilizers. An extreme relationship of the elastic modulus on the composition of the blend at a PE content (5–20 wt.%) was revealed. The use of EBM model representations made it possible to identify the reasons for this relationship, namely, the cumulative contribution of structural changes in PVC and the enhancement of interfacial adhesion due to the presence of a compatibilizer at the phase boundary.

Electrical Properties of Sandwich-like Multilevel Phase Structure BNT-BT Lead-Free Piezoelectric Ceramics

Sandwich-like multilayer (BNT-0.05BT, BNT-0.07BT, and BNT-0.09BT) composite ceramics was performed by traditional solid-state reaction method. The results show that the dielectric properties of (Bi1/2Na1/2)TiO3-BaTiO3 (BNT-BT) ceramics were improved significantly from 580 to 1278. By fitting the dielectric constant ɛ r with electric field intensity, the linear relationship conformed to Rayleigh formula, and the dielectric properties of the loops were studied. The results show that the dielectric properties were improved mainly because the intrinsic contribution of structural changes of composite ceramics increased. As the temperature rises, the dielectric response of ceramics to the electric field increases gradually.

Structural Change for Sustainable Development in Economy: A Literature Review

Research background: Climate change stimulates unfavorable global socio-economic consequences, which question economic structures, require sustainable development. Reaching sustainable development in economy relates to structural change. However, scientists rarely focus on structural change and sustainable development in the pure economic subject area. Purpose of the article: The article aims to summarize and classify the knowledge about contribution and potential of structural change for sustainable development in economy using research experience. The author considers the articles published exactly in the economic subject area, in which scientists terminologically focus on structural change and sustainable development. Methods: The search parameter - keywords and limitation - subject area determine the selection of suitable material for the research purpose. The author applies monographic method, logical analysis method, scientific induction method for the analysis of the selected material. Findings & Value added: The articles selected according to the limitations demonstrate that manufacturing is the most commonly analyzed sector followed by energy sector, tourism and decomposition of economy depending on sectoral efficiency. According to the material analyzed in the economic subject area, the contribution of structural change to sustainable development is considered in case studies with focus on decomposition of sectoral structure of local economies. Potential of structural change to sustainable development is considered in general terms and relates to energy efficiency, introduction of new technologies, and involvement of all stakeholders. Thus, it is possible to highlight the factors necessary for structural change, which work towards sustainable development in economy – attitude, efficiency, new technologies and wide range of participants.

Significant contribution of fibrils on pulp fiber surface to water retention value

Abstract The contribution of structural changes of softwood bleached kraft pulp (SBKP) fibers and partly dried SBKP handsheets to their water retention values (WRVs) was studied. Two factors related to mesopores and macropores, which were determined for super critical point (SCP)-dried SBKP sheet samples, should participate in the WRVs determined for wet SBKP sheet samples. The mesopores are formed during pulping/bleaching to remove lignin and a part of hemicelluloses that are present originally in wood cell walls. The combined volumes of mesopores and macropores (totally < ∼0.6 g g−1) in SBKP fibers after SCP drying were significantly lower than the entire WRV (∼1.6 g g−1) of the original never-dried SBKP. We hypothesize that external fibrils of SBKP fibers are formed during pulping, bleaching, washing, pressure-screening, and pressing processes at high and low solid contents in water under high shear forces. The WRV can be used as an indicator to evaluate such structural changes of external fibrils in pulp fibers and paper sheets during drying/wetting in papermaking process as well as in use under various conditions. In contrast, changes in mesopore and macropore volumes determined for SCP-dried sheets cannot properly detect such structural changes of external fibrils.

Structural Change, Expanding Informality and Labor Productivity Growth in Russia

Strong growth, intensive structural change, and expanding informality have characterized many developing and emerging economies in recent decades. Yet most empirical investigations into the relationship between structural change and productivity growth overlook informality. This paper includes the informal sector in an analysis of the effects of structural changes in the Russian economy on aggregate labor productivity growth. Using a newly developed dataset for 34 industries covering the period 1995–2012 and applying three alternative approaches, aggregate labor productivity growth is decomposed into intra‐industry and inter‐industry contributions. All three approaches show that the overall contribution of structural change is growth enhancing, significant, and decreasing over time. Labor reallocation from the formal sector to the informal sector tends to reduce growth through the extension of informal activities with low productivity levels. Sectoral labor reallocation effects are found to be highly sensitive to the methods applied.

Toward the Experimental Understanding of the Energy Storage Mechanism and Ion Dynamics in Ionic Liquid Based Supercapacitors

AbstractA series of salt‐templated carbons with gradually changed pore structure and their corresponding nitrogen‐doped analogues are synthesized and applied as model systems to thoroughly study the ion migration dynamics and energy storage mechanism in hierarchical pore structures with different surface functionalization in electric double‐layer capacitors with a model ionic liquid electrolyte (1‐ethyl‐3‐methylimidazolium tetrafluoroborate). Ion conformation and phase variation during the charging/discharging process and their contribution to the energy storage mechanism are investigated. A significant contribution of structural changes in the bulk of the ionic liquid electrolyte strengthening charge storage in the electric double‐layer beyond the usual expectations is uncovered. Furthermore, a quantitative model of the structure–dynamics relationship is proposed, in which the optimal ratio of mesopores to micropores is determined to be 3:1 in pore volume. Below this ratio, the ion dynamics can be promoted by increasing mesopore content and/or doping with nitrogen, while those parameters show only minor influence when the ratio is surpassing 3:1. Nitrogen doping in this system improves the rate capability (due to the enhanced ion transport dynamics) rather than the amount of energy stored.

Economic Growth, Structural Change and Productive Employment Linkages in India

This article presents a quantitative analysis of growth, structural change and employment linkages at the aggregate level and by sector under the state- and market-led regimes in India. The underlying objectives are: (a) to understand how economic liberalization has affected the economic and labour market structures, and linkages thereof; and (b) to analyse how these dynamics have affected the generation of productive employment in the economy. The analysis is based on Shapley decompositions. Our results suggest that the contribution of structural change in employment to growth declined drastically and secularly as the country transitioned to a high-growth regime driven by globalization. The sector-level analysis indicates that employment opportunities are not being created in high-productivity sectors and segments. Thus, despite a high-growth rate in GDP per capita and productivity-enhancing structural transformation in GDP, a vast population is still trapped in employment that cannot be qualified as productive employment. The study attributes it to trade-induced economic specialization accompanied with weakening of internal inter-sectoral linkages. The article makes a strong case for strategic government intervention to broad base structural change for generating productive employment, which is at the core of poverty reduction. JEL codes: E24, O14, O4

Structural change in Ethiopia

AbstractThis article investigates the pace and pattern of structural change in Ethiopia. It departs from the existing literature in two main ways. First, it uses a methodology that enables a more comprehensive assessment of structural change. Second, it entailed the construction of a consistent dataset for Ethiopia—comprising three labour force surveys—tracking 10 economic sectors between 1999 and 2013. Our analysis suggests that the structure of production has changed considerably, but that shifts in the composition of employment have lagged behind. Output per capita growth has been strong and mainly driven by within‐sector productivity improvements. However, the contribution of structural change has increased over time, which is encouraging. Evidence of a growing demographic dividend is also uncovered.

Structural Change, Expanding Informality and Labour Productivity Growth in Russia

Intensive growth, structural change and expanding informality has characterized many developing and emerging economies in recent decades. Yet most empirical investigations into the relationship between structural change and productivity growth overlook informality. This paper includes the informal sector in an analysis of the effects of structural changes in the Russian economy on aggre-gate labour productivity growth. Using a newly developed dataset for 34 industries covering the period 1995–2012 and applying three alternative approaches, aggregate labour productivity growth is decomposed into intra-industry and inter-industry contributions. All three approaches show that the overall contribution of structural change is growth-enhancing, significant and attenuating over time. Labour reallocation from the formal sector to the informal sector tends to reduce growth through the extension of informal activities with low productivity levels. Sectoral labour reallocation effects are found to be highly sensitive to the methods applied.

Structural Change, Expanding Informality and Labour Productivity Growth in Russia

Intensive growth, structural change and expanding informality has characterized many developing and emerging economies in recent decades. Yet most empirical investigations into the relationship between structural change and productivity growth overlook informality. This paper includes the informal sector in an analysis of the effects of structural changes in the Russian economy on aggre-gate labour productivity growth. Using a newly developed dataset for 34 industries covering the period 1995–2012 and applying three alternative approaches, aggregate labour productivity growth is decomposed into intra-industry and inter-industry contributions. All three approaches show that the overall contribution of structural change is growth-enhancing, significant and attenuating over time. Labour reallocation from the formal sector to the informal sector tends to reduce growth through the extension of informal activities with low productivity levels. Sectoral labour reallocation effects are found to be highly sensitive to the methods applied.

Low-field-enhanced unusual hysteresis produced by metamagnetism of the MnP clusters in the insulating CdGeP2 matrix under pressure

Hydrostatic pressure studies of the isothermal magnetization and volume changes up to 7 GPa of magnetic composite containing MnP clusters in an insulating $\mathrm{CdGe}{\mathrm{P}}_{2}$ matrix are presented. Instead of alleged superparamagnetic behavior, a pressure-induced magnetization process was found at zero magnetic field, showing gradual enhancement in a low-field regime up to $H\ensuremath{\geqslant}5$ kOe. The simultaneous application of pressure and magnetic field reconfigures the MnP clusters with antiferromagnetic alignment, followed by onset of a field-induced metamagnetic transition. An unusual hysteresis in magnetization after pressure cycling is observed, which is also enhanced by application of the magnetic field, and indicates reversible metamagnetism of MnP clusters. We relate these effects to the major contribution of structural changes in the composite, where limited volume reduction by 1.8% is observed at $P\ensuremath{\sim}5.2$ GPa.

Contribution of Structural Change to Productivity Growth: Evidence from Tunisia

The objective of the article is to analyse the dynamics of sectoral productivity growth in Tunisia and assess the contribution of structural change to these dynamics. Using sectoral and firm data, we show that productivity increased at a relatively sustained pace in Tunisia in the last three decades, but that the contribution of structural change remained limited. Trade reforms had a positive impact, while investment and the policies implemented in the mid-1990s had negative effects on structural change. The main impediments are barriers to entry in some sectors, the inefficiency of factor markets and the focus of the firms' upgrading programme only on some selected sectors.

A Tale of Two Fascisms: Labour Productivity Growth and Competition Policy in Italy, 1911-1951

This paper offers the first quantitative assessment of labour productivity dynamics within Italy's industrial sector over the period 1911-1951 and of their links with competition policy. By relying on a newly compiled dataset and on fresh labour productivity estimates, we find that the earlier period of the Fascist era was characterised by a productivity boom, which ended and was reversed following the switch to a more interventionist industrial policy. In the overall period 1911-1951, new industries did not perform any better than the old ones and labour productivity growth was explained largely by internal productivity growth within industrial sectors rather than from the contribution of structural change from old to new industries. Finally, we find that reductions in the level of competition, induced by specific policies, were associated with lower productivity growth. This paper thus casts a shadow on the optimist accounts of Fascist industrial policy and confirms the findings of a revisionist literature minimising the positive role played by the State in the earlier stages of Italian industrialization.

A Combination of Structural and Cis-Regulatory Factors Drives Biochemical Differences in Drosophila melanogaster Malic Enzyme

The evolutionary significance of molecular variation is still contentious, with much current interest focusing on the relative contribution of structural changes in proteins versus regulatory variation in gene expression. We present a population genetic and biochemical study of molecular variation at the malic enzyme locus (Men) in Drosophila melanogaster. Two amino acid polymorphisms appear to affect substrate-binding kinetics, while only one appears to affect thermal stability. Interestingly, we find that enzyme activity differences previously assigned to one of the polymorphisms may, instead, be a function of linked regulatory differences. These results suggest that both regulatory and structural changes contribute to differences in protein function. Our examination of the Men coding sequences reveals no evidence for selection acting on the polymorphisms, but earlier work on this enzyme indicates that the biochemical variation observed has physiological repercussions and therefore could potentially be under natural selection.

Phenotypic Consequences of Copy Number Variation: Insights from Smith-Magenis and Potocki-Lupski Syndrome Mouse Models

Author SummaryMammalian genomes contain many forms of genetic variation. For example, some genome segments were shown to vary in their number of copies between individuals of the same species, i.e. there is a range of number of copies in the normal population instead of the usual two copies (one per chromosome). These genetic differences play an important role in determining the phenotype (the observable characteristics) of each individual. We do not know, however, if such influences are brought about solely through changes in the number of copies of the genomic segments (and of the genes that map within) or if the structural modification of the genome per se also plays a role in the outcome. We use mouse models with different number of copies of the same genomic region to show that rearrangements of the genetic materials can affect the phenotype independently of the dosage of the rearranged region.

Produtividade do trabalho e mudança estrutural nas indústrias brasileiras extrativa e de transformação, 1970-2001

Using an indicator of labor productivity, this paper aims to assess the contribution of structural changes in the Brazilian manufacturing and mining industries to productivity growth, during the 1970-2001 period. The conclusion is that: (i) there is no evidence to sustain that the Brazilian industry has definitely reversed the productivity growth rates slowdown trend; (ii) there is no clear evidence of a positive influence of the structural bonus; and (iii) job creation seems to be concentrated in low productivity growth sectors.

Airway hyperresponsiveness in the elderly: prevalence and clinical implications

Airway hyperresponsiveness is associated with an increased risk of developing respiratory symptoms. The assessment of airway hyperresponsiveness can provide valuable information regarding the natural course of respiratory diseases. However, little information is available for populations of more advanced age, and data are conflicting. It was assessed whether age influences the occurrence of airway hyperresponsiveness by reviewing those studies that specifically addressed this issue, and attempting to identify the factors responsible for discrepancies between studies. Eighteen studies, published between 1983 and 2002, are included in this review. Overall, the results of the analysis are in favour of a positive association between age and airway hyperresponsiveness, the prevalence of which appears to increase in the elderly. The most important determinants were reduced lung function, probably due to geometric factors, and a history of smoking, primarily because of the length of exposure, although acute effects were also demonstrated. Atopy should also be considered as an independent determinant of airway hyperresponsiveness in the elderly population. In addition, inflammatory and neuronal mechanisms could be involved. Finally, the role of sex requires further investigation. Assessing the impact of age on the occurrence of airway hyperresponsiveness has important implications: the age-associated alterations to the lung provide a model for evaluating the contribution of structural changes to the pathogenesis of airway hyperresponsiveness. From a clinical standpoint, evaluation of the magnitude of airway hyperresponsiveness could permit the early identification of individuals who are at risk, even at more advanced age. Assessment of airway hyperresponsiveness in the aged should be considered as an additional tool in the diagnostic work-up in the subset of elderly subjects with long-term smoking exposure and/or documented atopy.

Basic mechanisms of lung inflammation: executive summary of the first Lung Science Meeting of the European Respiratory Society at Taormina, Italy in 2003.

The contribution of structural changes and the biology of lung cells to pulmonary disease was emphasised and contrasted with the inflammatory response at the first Lung Science Conference held at Taormina, Italy 26–28 March 2003 (table 1⇓). Here the basic mechanisms of inflammation and their relevance to lung diseases are discussed. For more information on the intracellular events discussed, look at and listen to individual talks on the European Respiratory Society web page at http://www.ersnet.org/taormina. View this table: 1 Central messages from Taormina Both the environment (“the air we breathe and the food we eat”) and the genetic potential (correct gene products expressed at the right place at the right time) contribute to homeostasis in the lung as well as to pathological deviation. Examples of environmental factors that contribute to the development of pulmonary disease were cigarette smoke condensate 1, lipopolysaccharide 2 and diesel exhaust particles. The redox potential of the lungs 3 is critical to the response to environmental insults and the subsequent expression of lung diseases 4. Genetic contributions to risk factors were discussed for sarcoidosis 5 and idiopathic fibrosis in surfactant protein (SP)‐D variants 6. A wound inflicted upon the pulmonary epithelium will attempt to heal. Concurrently, the immune system will respond with an inflammatory response to protect against imminent infection. Among the stimulating talks on repair, growth and differentiation of structural cells, the description of how embryos heal wounds 7, 8 was most fascinating. Using green fluorescent protein­labelled actin in drosophila and zebra fish, video sequences of differentiating embryos and wounded embryos showed how the epithelial cells stretch and pull toward each other in an attempt to close a wound. At the ends of the wound, lamellipodia of cells meet and interdigitate to reform the intact epithelium. If the drosophila homologue transforming growth factor (TGF)‐β PUK …

Serial echocardiographic assessment of left ventricular geometry and function after large myocardial infarction in the rat.

The development of heart failure after acute myocardial infarction (MI) may be related to alterations of left ventricular (LV) structure and function. Pathological LV remodeling may exacerbate systolic and diastolic dysfunction because increased cavity dimensions tend to increase LV wall stress. Unfortunately, many complicating factors have made it difficult to clearly define the time course of LV remodeling after myocardial infarction in patients, and the contribution of structural changes to altered function has not been fully explored. To determine the type, magnitude, and time course of changes in LV geometry and function, we performed transthoracic Doppler echocardiographic examinations in rats before and 1 and 6 weeks after transmural MI induced by coronary ligation. LV internal diastolic dimension was greater in infarcted than in sham-operated rats at 1 and 6 weeks after MI (9.4 +/- 0.6 versus 8.0 +/- 0.5 and 10.1 +/- 0.9 versus 8.5 +/- 0.9 mm, respectively; P < .05 compared with sham-operated rats). There was significant thinning of the infarcted anterior wall at 1 and 6 weeks (0.99 +/- 0.2 versus 1.33 +/- 0.19 and 0.96 +/- 0.22 versus 1.51 +/- 0.18 mm, P < .05), while the thickness of the noninfarcted posterior wall increased but was not different from normal growth in sham-operated rats. Six weeks after surgery, fractional shortening was impaired (11 +/- 5% versus 35 +/- 5%, P < .05), and systolic thickening of the noninfarcted posterior wall was depressed (38 +/- 9% versus 67 +/- 18%, P < .05) in infarcted rats compared with shams. These changes in structure and systolic function were accompanied by progressive alterations in LV diastolic filling. Peak early filling velocity increased at 1 and 6 weeks in MI rats (91 +/- 9 versus 79 +/- 9 and 100 +/- 14 versus 74 +/- 11 cm/s, P < .05), and the deceleration rate of the early filling wave was more rapid in rats with MI (21.6 +/- 5.0 versus 15.6 +/- 3.1 and 26.1 +/- 9.8 versus 11.2 +/- 2.7 m/s2, P < .05). Late filling velocity was decreased (16 +/- 15 versus 33 +/- 7 and 15 +/- 18 versus 34 +/- 5 cm/s, P < .05), resulting in a marked increase in the ratio of early to late filling. The peak velocity and the velocity-time integral of LV outflow did not change after MI. Postinfarction LV remodeling in the rat is characterized by progressive cavity dilatation, inadequate hypertrophy of the surviving myocardium, the gradual development of regional contractile dysfunction in noninfarcted segments, and marked abnormalities of diastolic filling. These changes can be tracked longitudinally with transthoracic echocardiography.