A geometric view of cryptographic equation solving

This paper considers the geometric properties of the Relinearisation algorithm and of the XL algorithm used in cryptology for equation solving. We give a formal description of each algorithm in terms of projective geometry, making particular use of the Veronese variety. We establish the fundamental geometrical connection between the two algorithms and show how both algorithms can be viewed as being equivalent to the problem of finding a matrix of low rank in the linear span of a collection of matrices, a problem sometimes known as the MinRank problem. Furthermore, we generalise the XL algorithm to a geometrically invariant algorithm, which we term the GeometricXL algorithm. The GeometricXL algorithm is a technique which can solve certain equation systems that are not easily soluble by the XL algorithm or by Groebner basis methods

Spectral splitting photovoltaics using perovskite and wideband dye-sensitized solar cells

The extension of the light absorption of photovoltaics into the near-infrared region is important to increase the energy conversion efficiency. Although the progress of the lead halide perovskite solar cells is remarkable, and high conversion efficiency of >20% has been reached, their absorption limit on the long-wavelength side is similar to 800 nm. To further enhance the conversion efficiency of perovskite-based photovoltaics, a hybridized system with near-infrared photovoltaics is a useful approach. Here we report a panchromatic sensitizer, coded DX3, that exhibits a broad response into the near-infrared, up to similar to 1100 nm, and a photocurrent density exceeding 30 mA cm(-2) in simulated air mass 1.5 standard solar radiation. Using the DX3-based dye-sensitized solar cell in conjunction with a perovskite cell that harvests visible light, the hybridized mesoscopic photovoltaics achieved a conversion efficiency of 21.5% using a system of spectral splitting.open0

MOLECULAR BIOLOGY AND PHYSIOLOGY Fiber Initiation in 18 Cultivars and Experimental Lines of Three Gossypium Species

ABSTRACT A new technique was developed to study the cotton fiber initiation process and fiber initial densities. The goal was to provide an additional tool to cotton breeders and geneticists interested in fiber improvement. The objectives were to assess whether fiber initiation patterns reported for some Gossypium hirsutum L. and G. barbadense L. cultivars extend to a more diverse range of cultivars/lines; and to test if there is a relationship between fiber initials density, lint percentage, and fiber characteristics. This study was performed with 17 cultivars and experimental lines of G. hirsutum (upland cotton) and G. barbadense (Pima cotton) and one G. arboreum L. accession. The ovules were extracted from flowers at the day of anthesis and 1 and 2 d thereafter, stained with a fluorescent dye, DiOC 6 (3) (3,3′-dihexyloxacarbocyanine iodide), and observed under a light microscope. Staining cotton fiber initials with DiOC 6 (3) enabled the evaluation of a greater number of samples than the more time-consuming scanning electron microscopy protocols to assess the fiber initiation process. There were significant differences in fiber initial densities among cultivars and lines but these did not cluster into "upland" and "Pima" types as had been expected. Upland and Pima fiber initiation occurred at anthesis, whereas Sea Island Pima initiation was delayed a day. A delay in fiber initiation was also confirmed in fuzzless mutant lines. Fiber initial densities were not found to be useful predictors of lint percentage

Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to isolate and identify the antifungal compounds from the extracts of <it>Schinus terebinthifolius </it>(Anacardiaceae) against clinical isolates of the pathogenic fungus <it>Paracoccidioides brasiliensis</it>.</p> <p>Methods</p> <p>The hexane and dichlomethane fractions from leaves and stems of <it>S. terebinthifolius </it>were fractionated using several chromatography techniques to afford four compounds.</p> <p>Results</p> <p>The compounds isolated from <it>S. terebinthifolius </it>were identified as schinol (<b>1</b>), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (<b>2</b>), quercetin (<b>3</b>), and kaempferol (<b>4</b>). Compounds <b>1 </b>and <b>2 </b>were active against different strains of <it>P. brasiliensis</it>, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound <b>1 </b>with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. <it>terebinthifolius </it>were not able to inhibit cell wall synthesis or assembly using the sorbitol assay.</p> <p>Conclusion</p> <p>This work reveals for the first time the occurrence of compound <b>2 </b>and discloses activity of compounds <b>1 </b>and <b>2 </b>against several clinical isolates of <it>P. brasiliensi</it>s. These results justify further studies to clarify the mechanisms of action of these compounds.</p

Maternal hyperleptinemia is associated with male offspring’s altered vascular function and structure in mice

Children of mothers with gestational diabetes have greater risk of developing hypertension but little is known about the mechanisms by which this occurs. The objective of this study was to test the hypothesis that high maternal concentrations of leptin during pregnancy, which are present in mothers with gestational diabetes and/or obesity, alter blood pressure, vascular structure and vascular function in offspring. Wildtype (WT) offspring of hyperleptinemic, normoglycemic, Lepr db/+ dams were compared to genotype matched offspring of WT-control dams. Vascular function was assessed in male offspring at 6, and at 31 weeks of age after half the offspring had been fed a high fat, high sucrose diet (HFD) for 6 weeks. Blood pressure was increased by HFD but not affected by maternal hyperleptinemia. On a standard diet, offspring of hyperleptinemic dams had outwardly remodeled mesenteric arteries and an enhanced vasodilatory response to insulin. In offspring of WT but not Leprdb/+ dams, HFD induced vessel hypertrophy and enhanced vasodilatory responses to acetylcholine, while HFD reduced insulin responsiveness in offspring of hyperleptinemic dams. Offspring of hyperleptinemic dams had stiffer arteries regardless of diet. Therefore, while maternal hyperleptinemia was largely beneficial to offspring vascular health under astandard diet, it had detrimental effects in offspring fed HFD. These results suggest that circulating maternal leptin concentrations may interact with other factors in the pre- and post-natal environments to contribute to altered vascular function in offspring of diabetic pregnancie

Depressive symptoms, fatigue and social relationships influenced physical activity in frail older community-dwellers during the Spanish lockdown due to the COVID-19 pandemic

Due to the dramatic impact of the COVID-19 pandemic, Spain underwent a strict lockdown (March-May 2020). How the lockdown modified older adults' physical activity (PA) has been poorly described. This research assesses the effect of the lockdown on PA levels and identifies predictors of sufficient/insufficient PA in frail older community-dwellers. Community-dwelling participants from the +ÀGIL Barcelona frailty intervention program, suspended during the pandemic, underwent a phone-assessment during the lockdown. PA was measured before and after the lockdown using the Brief Physical Activity Assessment Tool (BPAAT). We included 98 frail older adults free of COVID-19 (mean age = 82.7 years, 66.3% women, mean Short Physical Performance Battery = 8.1 points). About one third of participants (32.2%) were not meeting sufficient PA levels at the end of the lockdown. Depressive symptoms (OR = 0.12, CI95% = 0.02-0.55) and fatigue (OR = 0.11, CI95% = 0.03-0.44) decreased the odds of maintaining sufficient PA, whereas maintaining social networks (OR = 5.07, CI95% = 1.60-16.08) and reading (OR = 6.29, CI95% = 1.66-23.90) increased it. Living alone was associated with the reduction of PA levels (b = −1.30, CI95% = −2.14-−0.46). In our sample, pre-lockdown mental health, frailty-related symptoms and social relationships were consistently associated with both PA levels during-lockdown and pre-post change. These data suggest considering specific plans to maintain PA levels in frail older community-dwellers

Assessment the flood hazard arising from land use change in a forested catchment in northern Iran

The provinces of northern Iran that border the Caspian Sea are forested and may be prone to increased risks of flooding due to deforestation and other land use changes, in addition to climate change effects. This research investigated changes in runoff from a small forested catchment in northern Iran for several land use change scenarios and the effects of higher rainfall and high antecedent soil moisture. Peak discharges and total runoff volumes from the catchment were estimated using the US Soil Conservation Service 'Curve Number' (SCS-CN) method and the SCS dimensionless unit hydrograph. This method was selected for reasons of data availability and operational simplicity for flood managers. A GIS was used to manipulate spatial data for use in the catchment runoff modelling. The results show that runoff is predicted to increase as a result of deforestation, which is dependent on the proportion of the catchment area affected. However, climate change presents a significant flood hazard even in the absence of deforestation. Other land use changes may reduce the peak discharges of all return period floods. Therefore a future ban on timber extraction, combined with agricultural utilisation of rangeland, could prove effective as 'nature-based' flood reduction measures throughout northern Iran

Cyclic stretch increases splicing noise rate in cultured human fibroblasts

BACKGROUND: Mechanical forces are known to alter the expression of genes, but it has so far not been reported whether they may influence the fidelity of nucleus-based processes. One experimental approach permitting to address this question is the application of cyclic stretch to cultured human fibroblasts. As a marker for the precision of nucleus-based processes, the number of errors that occur during co-transcriptional splicing can then be measured. This so-called splicing noise is found at low frequency in pre-mRNA splicing. FINDINGS: The amount of splicing noise was measured by RT-qPCR of seven exon skips from the test genes AATF, MAP3K11, NF1, PCGF2, POLR2A and RABAC1. In cells treated by altered uniaxial cyclic stretching for 18 h, a uniform and significant increase of splicing noise was found for all detectable exon skips. CONCLUSION: Our data demonstrate that application of cyclic stretch to cultured fibroblasts correlates with a reduced transcriptional fidelity caused by increasing splicing noise