338 research outputs found
Settlements of Rigid Rectangular Footings on Layered Soils
Solutions to calculate the settlement of footings resting on a semi-infinite or finite soil layer are readily \ud
available in the literature. Whitman and Richart (1967) proposed the vertical settlement factors for rigid \ud
rectangular footing resting on a semi-infinite layer of soil. The equation takes into consideration the \ud
aspect ratio, defined as ratio of length to width, L/B, of the footing through a parameter āĪ²zā. Sovinc (1969) proposed the settlement factors for a rectangular footing on a finite layer of homogeneous soil underlain by a rigid base. He also considered the effect of L/B on the settlement of the footing. However, Sovincās solution is given only for one Poissonās ratio value equal to 0.5
The Correlation Between Students' Grammar and Vocabulary Mastery and Their Reading Ability
Penelitian bertujuan menghubungkan korelasi antara penguasaan tata bahasa siswa terhadap kemampuan membaca. Penelitian ini merupakan penelitian kuantitatif dengan menggunakan desain ex-post facto. Sampel dipilih dengan menggunakan probabiliti sampling acak sederhana. Kelas X 5 terpilih sebagai kelas sampel dan kelas X 6 dipilih sebagai kelas uji coba. Data dikumpulkan dengan pemberian tes tata bahasa, tes kosa kata, dan tes membaca pemahaman. Tidak ada pengajaran yang dilakukan di kelas sampel. Data dianalisis dengan menggunakan statistik (SPSS) versi 15.0. Hasil pengujian menunjukkan bahwa koefisien korelasi penguasaan tata bahasa siswa dan penguasaan kosa kata dan kemampuan membaca mereka adalah 0,803 pada tingkat signifikan 0,01. Ini berarti bahwa variabel tersebut berkorelasi positif. Koefisien korelasi (nilai p) lebih tinggi dari rtabel (0,803> 0,393). Penelitian ini berarti ada hubungan yang signifikan antara tata bahasa siswa dan penguasaan kosa kata dan kemampuan membaca mereka. This research is quantitative by nature using ex-post facto design. The sample was chosen by using simple probability random sampling. Class X 5 was chosen as the sample class and class X 6 was chosen as the try out class. The data were collected by administering grammar test, vocabulary test, and reading comprehension test. There were no treatments conducted in the sample class. The data were analyzed by using Statistical Packaged for Social Science (SPSS) version 15.0.The test result showed that the coefficient correlation of students' grammar mastery and vocabulary mastery and their reading ability is 0.803 at the significant level of 0.01. It means that those variables positively correlated. The correlation coefficient (rvalue) is higher than rtable (0.803 > 0.393). It means that there is significant correlation between students' grammar and vocabulary mastery and their reading ability
Chemical characteristics and source apportionment of aerosols over Indian Ocean during INDOEX-1999
During INDOEX IFP-99, the samples of aerosols were collected onboard ORV Sagar Kanya over Indian Ocean along the cruise track, for chemical characterization and identification of dominating sources of aerosols. The concentrations of nss-SO4, nss-Ca, nss-Mg, NO3, K, NH4 and SO2 were observed to be significantly higher before ITCZ in northern hemisphere than across ITCZ in southern hemisphere. In this study, variation of concentrations of nss-SO4, nss-Ca and nss-K with respect to change in latitude, wind direction, wind speed and relative humidity have been highlighted. North of ITCZ, nss-SO4 varied from 2.20 to 18.31 Ī¼g/m3 and south of ITCZ from 0.50 to 2.79 Ī¼g/m3 while nss-Ca varied from 0.02 to 0.72 Ī¼g/m3 north of ITCZ and from 0.01 to 0.14 Ī¼g/m3 south of ITCZ. nss-K ranged 0.09-1.43 Ī¼g/m3 and 0.07-0.60 Ī¼g/m3 before ITCZ and across ITCZ respectively. nss-Ca and nss-SO4 were contributed mainly by NNW and ENE winds while nss-K was observed to be contributed mainly by SSW and ENE winds. Wind speed greater than 4.5 m/s negatively influenced the concentration of nss-Ca concentrations. Correlation coefficients of nss-SO4 with SO2 (r = 0.7) and RH (r = 0.5) suggested a significant contribution of nss-SO4 by aqueous phase oxidation of SO2. Using PCA, four major sources namely sea salt, biogenic combustion, secondary SO4 and crustal contribution were identified over Indian Ocean during INDOEX period
Assessment of power spectral density of microvascular hemodynamics in skeletal muscles at very low and low-frequency via near-infrared diffuse optical spectroscopies
In this work, we used a hybrid time domain near-infrared spectroscopy (TD-NIRS) and diffuse correlation spectroscopy (DCS) device to retrieve hemoglobin and blood flow oscillations of skeletal muscle microvasculature. We focused on very low (VLF) and low-frequency (LF) oscillations (i.e., frequency lower than 0.145 Hz), that are related to myogenic, neurogenic and endothelial activities. We measured power spectral density (PSD) of blood flow and hemoglobin concentration in four muscles (thenar eminence, plantar fascia, sternocleidomastoid and forearm) of 14 healthy volunteers to highlight possible differences in microvascular hemodynamic oscillations. We observed larger PSDs for blood flow compared to hemoglobin concentration, in particular in case of distal muscles (i.e., thenar eminence and plantar fascia). Finally, we compared the PSDs measured on the thenar eminence of healthy subjects with the ones measured on a septic patient in the intensive care unit: lower power in the endothelial-dependent frequency band, and larger power in the myogenic ones were observed in the septic patient, in accordance with previous works based on laser doppler flowmetry
Co-production of hydrogen and ethanol from glucose in Escherichia coli by activation of pentose-phosphate pathway through deletion of phosphoglucose isomerase (pgi) and overexpression of glucose-6-phosphate dehydrogenase (zwf) and 6-phosphogluconate dehydrogenase (gnd)
Background: Biologically, hydrogen (H-2) can be produced through dark fermentation and photofermentation. Dark fermentation is fast in rate and simple in reactor design, but H-2 production yield is unsatisfactorily low as < 4 mol H-2/ mol glucose. To address this challenge, simultaneous production of H-2 and ethanol has been suggested. Co-production of ethanol andH(2) requires enhanced formation of NAD(P) H during catabolism of glucose, which can be accomplished by diversion of glycolytic flux from the Embden-Meyerh-of-Parnas (EMP) pathway to the pentose-phosphate (PP) pathway in Escherichia coli. However, the disruption of pgi (phosphoglucose isomerase) for complete diversion of carbon flux to the PP pathway made E. coli unable to grow on glucose under anaerobic condition. Results: Here, we demonstrate that, when glucose-6-phosphate dehydrogenase (Zwf) and 6-phosphogluconate dehydrogenase (Gnd), two major enzymes of the PP pathway, are homologously overexpressed, E. coli.pgi can recover its anaerobic growth capability on glucose. Further, with additional deletions of Delta hycA,Delta hyaAB,Delta hybBC,Delta ldhA, and Delta frdAB, the recombinant.pgi mutant could produce 1.69 mol H-2 and 1.50 mol ethanol from 1 mol glucose. However, acetate was produced at 0.18 mol mol(-1) glucose, indicating that some carbon is metabolized through the Entner-Doudoroff (ED) pathway. To further improve the flux via the PP pathway, heterologous zwf and gnd from Leuconostoc mesenteroides and Gluconobacter oxydans, respectively, which are less inhibited by NADPH, were overexpressed. The new recombinant produced more ethanol at 1.62 mol mol(-1) glucose along with 1.74 mol H-2 mol(-1) glucose, which are close to the theoretically maximal yields, 1.67 mol mol(-1) each for ethanol andH(2). However, the attempt to delete the ED pathway in the.pgi mutant to operate the PP pathway as the sole glycolytic route, was unsuccessful. Conclusions: By deletion of pgi and overexpression of heterologous zwf and gnd in E. coli Delta hycA Delta hyaAB Delta hybBC Delta ldhA Delta frdAB, two important biofuels, ethanol andH(2), could be successfully co-produced at high yields close to their theoretical maximums. The strains developed in this study should be applicable for the production of other biofuels and biochemicals, which requires supply of excessive reducing power under anaerobic conditions
The Metabochip, a Custom Genotyping Array for Genetic Studies of Metabolic, Cardiovascular, and Anthropometric Traits
PMCID: PMC3410907This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Responses of marine benthic microalgae to elevated CO<inf>2</inf>
Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems. Ā© 2011 Springer-Verlag
Hundreds of variants clustered in genomic loci and biological pathways affect human height
Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (Pā<ā0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
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