In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal co...In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal construction sectors.The project owner wonders how much it costs to construct a building to an acceptable standard.Cost forecasting in general faces a number of difficulties,including a lack of available information during the preliminary phase of the project.As such,estimation becomes a crucial task involving great responsibility,which can lead to either more convincing results or chaotic situations.This study proposes a quick and effective method for estimating the cost of a single-storey F4 residential building.The modelling is done using multiple linear regression based on a statistical approach applied to twenty(20)projects that have already been completed.The project data are collected from design offices in the city of Brazzaville.The method expresses the cost of an F4 construction by certain project tasks,representing five(5)variables,three(3)of which are related to structural work and two(2)to finishing work,which are easy to determine.This approach,known as MECSO(Cost Estimation Model by Sub-structure),gives good results in all statistical tests carried out with reasonable confidence intervals.This method is very practical for engineering professionals working on the evaluation and control of construction costs.展开更多
UGT(UDP-dependent glycosyltransferase)family members are mainly involved in the modification of secondary metabolites,as well as plant stress responses.Previously,we identified the UGT gene MdUGT88F4 from Malus spp.In...UGT(UDP-dependent glycosyltransferase)family members are mainly involved in the modification of secondary metabolites,as well as plant stress responses.Previously,we identified the UGT gene MdUGT88F4 from Malus spp.In order to verify whether it had biological function in apple plants,we generated transgenic apple plants overexpressed MdUGT88F4 and treated them with salt stress.The results showed that it conferred enhanced salt stress tolerance in transgenic‘GL-3’apple(Malus domestica)plants.The expression of MdUGT88F4 was induced by salt stress,and overexpression of this gene alleviated the inhibitory effects of salt stress on the growth of apple plants.After 15 days of salt stress treatment(100 mmol·L^(-1)NaCl),necrotic spots were present on the leaves of wild-type(WT)plants,and none were observed on the leaves of transgenic plants overexpressing MdUGT88F4(OX).The relative electrolyte leakage and malondialdehyde content were lower and the total chlorophyll content and the relative water content were higher in OX plants than in WT plants.The photosynthetic efficiency was higher in OX plants than in WT plants under salt stress,which was consistent with their larger stomatal aperture;this might stem from a reduction in the content of abscisic acid.The production of reactive oxygen species was lower and the activities of antioxidant enzymes were higher in OX plants than in WT plants.In addition,OX plants accumulated less Na^(+)but more K^(+)than WT plants,and the expression of several genes involved in Na^(+)transport was upregulated in OX plants.MdUGT88F4 failed to promote the accumulation of isosalipurposide in vivo,and it was involved in isosalipurposide synthesis.Most of the flavonoid metabolites accumulated to a greater degree in OX plants than in WT plants.In summary,our results show that MdUGT88F4 positively regulates the salt stress response in apple plants,possibly by affecting stomatal movement,as well as the accumulation of ions and flavonoids.Our findings enhance our understanding of the metabolic mechanisms by which UGT proteins ameliorate the effects of salt stress in plants.展开更多
文摘In an environment where demand for housing is growing and the supply from public authorities is virtually non-existent,several mechanisms for housing production are emerging in the formal,semi-informal and informal construction sectors.The project owner wonders how much it costs to construct a building to an acceptable standard.Cost forecasting in general faces a number of difficulties,including a lack of available information during the preliminary phase of the project.As such,estimation becomes a crucial task involving great responsibility,which can lead to either more convincing results or chaotic situations.This study proposes a quick and effective method for estimating the cost of a single-storey F4 residential building.The modelling is done using multiple linear regression based on a statistical approach applied to twenty(20)projects that have already been completed.The project data are collected from design offices in the city of Brazzaville.The method expresses the cost of an F4 construction by certain project tasks,representing five(5)variables,three(3)of which are related to structural work and two(2)to finishing work,which are easy to determine.This approach,known as MECSO(Cost Estimation Model by Sub-structure),gives good results in all statistical tests carried out with reasonable confidence intervals.This method is very practical for engineering professionals working on the evaluation and control of construction costs.
基金supported by the Natural Science Basic Research Program of Shaanxi(Grant No.2023-JC-YB-170)the earmarked fund for the China Agricultural Research System(Grant No.CARS-27)the Key S&T Special Projects of Shannxi Province(Grant No.2020zdzx03-01-02)。
文摘UGT(UDP-dependent glycosyltransferase)family members are mainly involved in the modification of secondary metabolites,as well as plant stress responses.Previously,we identified the UGT gene MdUGT88F4 from Malus spp.In order to verify whether it had biological function in apple plants,we generated transgenic apple plants overexpressed MdUGT88F4 and treated them with salt stress.The results showed that it conferred enhanced salt stress tolerance in transgenic‘GL-3’apple(Malus domestica)plants.The expression of MdUGT88F4 was induced by salt stress,and overexpression of this gene alleviated the inhibitory effects of salt stress on the growth of apple plants.After 15 days of salt stress treatment(100 mmol·L^(-1)NaCl),necrotic spots were present on the leaves of wild-type(WT)plants,and none were observed on the leaves of transgenic plants overexpressing MdUGT88F4(OX).The relative electrolyte leakage and malondialdehyde content were lower and the total chlorophyll content and the relative water content were higher in OX plants than in WT plants.The photosynthetic efficiency was higher in OX plants than in WT plants under salt stress,which was consistent with their larger stomatal aperture;this might stem from a reduction in the content of abscisic acid.The production of reactive oxygen species was lower and the activities of antioxidant enzymes were higher in OX plants than in WT plants.In addition,OX plants accumulated less Na^(+)but more K^(+)than WT plants,and the expression of several genes involved in Na^(+)transport was upregulated in OX plants.MdUGT88F4 failed to promote the accumulation of isosalipurposide in vivo,and it was involved in isosalipurposide synthesis.Most of the flavonoid metabolites accumulated to a greater degree in OX plants than in WT plants.In summary,our results show that MdUGT88F4 positively regulates the salt stress response in apple plants,possibly by affecting stomatal movement,as well as the accumulation of ions and flavonoids.Our findings enhance our understanding of the metabolic mechanisms by which UGT proteins ameliorate the effects of salt stress in plants.
