720 research outputs found
Understanding policy and change: using a political economy analysis framework
The gap between the intent and the impact of policy for construction in the UK has been well established both in academic literature and in public discourse, contributing to repeated calls for transformation of the industry. The apparent failure of policy was investigated, taking policy at sector level as the unit of analysis. The objective was to both generate insight into the policy process and to establish a theoretical framework. Anticipating that the use of language, and the conflicting meanings attached to it by individual actors, is critical, an interpretive, abductive, research design was adopted. Twenty semi-structured interviews were carried out with a cross-section of industry actors. Methods of political economy analysis, used in other contexts, were adopted as the starting point for abduction. Analysis revealed flawed assumptions amongst stakeholders regarding the extent of the agency of central government in implementing change across such a heterogeneous and loosely coupled sector. Political economy analysis shows the impact of structural and institutional features on the sector in a systemic and holistic way, providing a template and visual model which supports collaborative and reflexive working, and forming a foundation for further research into policy for construction both in the UK and elsewhere
Analysis of subcellular metabolite levels of potato tubers (Solanum tuberosum) displaying alterations in cellular or extracellular sucrose metabolism
The expression of a heterologous invertase in potato tubers (Solanum tuberosum) in either the cytosol or apoplast leads to a decrease in total sucrose content and to an increase in glucose. Depending on the targeting of the enzyme different changes in phenotype and metabolism of the tubers occur: the cytosolic invertase expressing tubers show an increase in the glycolytic flux, accumulation of amino acids and organic acids, and the appearance of novel disaccharides; however, these changes are not observed when the enzyme is expressed in the apoplast [Roessner et al. (2001). Plant Cell, 13, 11-29]. The analysis of these lines raised several questions concerning the regulation of compartmentation of metabolites in potato tubers. In the current study we addressed these questions by performing comparative subcellular metabolite profiling. We demonstrate that: (i) hexoses accumulate in the vacuole independently of their site of production, but that the cytosolic invertase expression led to a strong increase in the cytosolic glucose concentration and decrease in cytosolic sucrose, whereas these effects were more moderate in the apoplastic expressors; (ii) three out of four of the novel compounds found in the cytosolic overexpressors accumulate in the same compartment; (iii) despite changes in absolute cellular content the subcellular distribution of amino acids was invariant in the invertase overexpressing tubers. These results are discussed in the context of current models of the compartmentation of primary metabolism in heterotrophic plant tissues
New period-luminosity and period-color relations of classical Cepheids: III. Cepheids in SMC
The photometric data for 460 classical, fundamental-mode Cepheids in the SMC
with log P > 0.4 measured by Udalski et al. have been analyzed for their P-C
and P-L relations, and for the variation of amplitude across the instability
strip in a similar way that was done in Papers I and II of this series. The SMC
Cepheids are bluer in (B-V) at a given period than for both the Galaxy and the
LMC. Their P-C relation in (B-V) is best fit by two lines intersecting at P=10
d. Their break must necessarily exist also in the P-L relations in B and/or V,
but remains hidden in the magnitude scatter. An additional pronounced break of
the P-L relations in B, V, and I occurs at P=2.5 d. The observed slope of the
lines of constant period in the HR diagram agrees with the theoretical
expectation from the pulsation equation. The largest amplitude Cepheids for
periods less than 13 days occur near the blue edge of the instability strip.
The sense is reversed in the period interval from 13 to 20 days, as in the
Galaxy and the LMC. The SMC P-L relation is significantly flatter than that for
the Galaxy, NGC 3351, 4321, M31, all of which have nearly the same steep slope.
The SMC P-L slope is intermediate between that of these steep slope cases and
the very shallow slope of Cepheids in the lower metallicity galaxies of NGC
3109 and Sextans A/B, consistent with the premise that the Cepheid P-L relation
varies from galaxy-to-galaxy as function of metallicity. Failure to take into
account the slope differences in the P-L relation as a function of metallicity
using Cepheids as distance indicators results in incorrect Cepheid distances.
Part of the 15% difference between our long distance scale - now independently
supported by TRGB distances - and that of the HST Key Project short scale is
due to the effect of using an inappropriate P-L relation.Comment: 9 pages, 10 figures, accepted for publication in Astronomy &
Astrophysic
Yield quantitative trait loci from wild tomato are predominately expressed by the shoot
Plant yield is the integrated outcome of processes taking place above and below ground. To explore genetic, environmental and developmental aspects of fruit yield in tomato, we phenotyped an introgression line (IL) population derived from a cross between the cultivated tomato (Solanum lycopersicum) and a wild species (Solanum pennellii). Both homozygous and heterozygous ILs were grown in irrigated and non-irrigated fields and evaluated for six yield components. Thirteen lines displayed transgressive segregation that increased agronomic yield consistently over 2 years and defined at least 11 independent yield-improving QTL. To determine if these QTL were expressed in the shoots or the roots of the plants, we conducted field trials of reciprocally grafted ILs; out of 13 lines with an effect on yield, 10 QTL were active in the shoot and only IL8-3 showed a consistent root effect. To further examine this unusual case, we evaluated the metabolic profiles of fruits from both the homo- and heterozygous lines for IL8-3 and compared these to those obtained from the fruit of their equivalent genotypes in the root effect population. We observed that several of these metabolic QTL, like the yield QTL, were root determined; however, further studies will be required to delineate the exact mechanism mediating this effect in this specific line. The results presented here suggest that genetic variation for root traits, in comparison to that present in the shoot, represents only a minor component in the determination of tomato fruit yield
Demethylation of oligogalacturonides by FaPE1 in the fruits of the wild strawberry Fragaria vesca triggers metabolic and transcriptional changes associated with defence and development of the fruit
Ectopic expression of the strawberry (Fragariaxananassa) gene FaPE1 encoding pectin methyl esterase produced in the wild species Fragaria vesca partially demethylated oligogalacturonides (OGAs), which conferred partial resistance of ripe fruits to the fungus Botrytis cinerea. Analyses of metabolic and transcriptional changes in the receptacle of the transgenic fruits revealed channelling of metabolites to aspartate and aromatic amino acids as well as phenolics, flavanones, and sesquiterpenoids, which was in parallel with the increased expression of some genes related to plant defence. The results illustrate the changes associated with resistance to B. cinerea in the transgenic F. vesca. These changes were accompanied by a significant decrease in the auxin content of the receptacle of the ripe fruits of transgenic F. vesca, and enhanced expression of some auxin-repressed genes. The role of these OGAs in fruit development was revealed by the larger size of the ripe fruits in transgenic F. vesca. When taken together these results show that in cultivated F. ananassa FaPE1 participates in the de-esterification of pectins and the generation of partially demethylated OGAs, which might reinforce the plant defence system and play an active role in fruit development
The radial pulsation of AI Aurigae
We present an analysis of eleven years of Stromgren by photometry of the red
semiregular variable star AI Aurigae. An early period determination of 63.9
days is confirmed by the long-term light curve behaviour. The light curve shows
semi-regular changes with a mean period of 65 days reaching an amplitude of 0.6
mag in some cycles. The b-y colour changes perfectly parallel the V light
curve, suggesting radial oscillation to be the main reason for the observed
variations. We estimate the main characteristics of the star (mass, radius,
effective temperature) that suggest radial pulsation in fundamental or first
overtone mode.Comment: 7 pages, 3 figures, accepted for publication in A&
The Distances to Open Clusters from Main-Sequence Fitting. IV. Galactic Cepheids, the LMC, and the Local Distance Scale
We derive the basic properties of seven Galactic open clusters containing
Cepheids and construct their period-luminosity (P-L) relations. For our cluster
main-sequence fitting we extend previous Hyades-based empirical
color-temperature corrections to hotter stars using the Pleiades as a template.
We use BVI_{C}JHK_{s} data to test the reddening law, and include metallicity
effects to perform a more comprehensive study for our clusters than prior
efforts. The ratio of total to selective extinction R_V that we derive is
consistent with expectations. Assuming the LMC P-L slopes, we find =
-3.93 +/- 0.07 (statistical) +/- 0.14 (systematic) for 10-day period Cepheids,
which is generally fainter than those in previous studies. Our results are
consistent with recent HST and Hipparcos parallax studies when using the
Wesenheit magnitudes W(VI). Uncertainties in reddening and metallicity are the
major remaining sources of error in the V-band P-L relation, but a higher
precision could be obtained with deeper optical and near-infrared cluster
photometry. We derive distances to NGC4258, the LMC, and M33 of (m - M)_0 =
29.28 +/- 0.10, 18.34 +/- 0.06, and 24.55 +/- 0.28, respectively, with an
additional systematic error of 0.16 mag in the P-L relations. The distance to
NGC4258 is in good agreement with the geometric distance derived from water
masers [\Delta (m - M)_0 = 0.01 +/- 0.24]; our value for M33 is less consistent
with the distance from an eclipsing binary [\Delta (m - M)_0 = 0.37 +/- 0.34];
our LMC distance is moderately shorter than the adopted distance in the HST Key
Project, which formally implies an increase in the Hubble constant of 7% +/-
8%.Comment: 28 pages, 21 figures; accepted for publication in the Ap
Classical Cepheid Pulsation Models. III. The Predictable Scenario
Within the current uncertainties in the treatment of the coupling between
pulsation and convection, limiting amplitude, nonlinear, convective models
appear the only viable approach for providing theoretical predictions about the
intrinsic properties of radial pulsators. In this paper we present the results
of a comprehensive set of Cepheid models computed within such theoretical
framework for selected assumptions on their original chemical composition.Comment: 24 pages, 1 latex file containing 6 tables, 10 postscript figures,
accepted for publication on Ap
Galacturonosyltransferase 4 silencing alters pectin composition and carbon partitioning in tomato
Pectin is a main component of the plant cell wall and is the most complex family of polysaccharides in nature. Its composition is essential for the normal growth and morphology pattern, as demonstrated by pectin-defective mutant phenotypes. Besides this basic role in plant physiology, in tomato, pectin structure contributes to very important quality traits such as fruit firmness. Sixty-seven different enzymatic activities have been suggested to be required for pectin biosynthesis, but only a few genes have been identified and studied so far. This study characterized the tomato galacturonosyltransferase (GAUT) family and performed a detailed functional study of the GAUT4 gene. The tomato genome harbours all genes orthologous to those described previously in Arabidopsis thaliana, and a transcriptional profile revealed that the GAUT4 gene was expressed at higher levels in developing organs. GAUT4-silenced tomato plants exhibited an increment in vegetative biomass associated with palisade parenchyma enlargement. Silenced fruits showed an altered pectin composition and accumulated less starch along with a reduced amount of pectin, which coincided with an increase in firmness. Moreover, the harvest index was dramatically reduced as a consequence of the reduction in the fruit weight and number. Altogether, these results suggest that, beyond its role in pectin biosynthesis, GAUT4 interferes with carbon metabolism, partitioning, and allocation. Hence, this cell-wall-related gene seems to be key in determining plant growth and fruit production in tomato
The Evolution of Grocery Wholesaling and Grocery Wholesalers in Ireland and Britain since the 1930s
Studies of industry evolution are relatively scarce outside of industries defined by narrow technological bases. Studies of wholesaling are rarer still. These are curious features given that it is probable that service industries behave differently to manufacturing ones and that wholesaling is such a key function of many economies. This paper looks at the evolution of grocery wholesaling and grocery wholesalers in Ireland and Britain since 1930. It focuses on the processes and drivers of the wholesale industry. Similarities and differences between the two countries are discussed. Particular emphasis is placed on the role of government action as a triggering mechanism for change and on the role of trade associations and industry leaders in developing and following through on market and non-market strategies. The pathways of industry evolution identified differ from those seen in manufacturing. They therefore raise a number of issues for the development of understanding and conceptualisation in industry evolution studies
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