The effect of cadmium and lead pollution on growth and physiological parameters of field beans (Vicia faba)

ArticleResearch on the impact of soil contamination on crops is important as plants directly take up heavy metals from the soil through the roots, so heavy metals can enter the food chain. The aim of this study was to investigate the impact of cadmium (Cd) and lead (Pb) pollution on growth and physiological parameters of field beans. Plants in the vegetation experiment were grown under controlled conditions. Changes in growth and physiological parameters were studied at five levels of Cd (0–25 mg L -1 ) and at 6 levels of Pb in substrate: from (0–1,000 mg L -1 ) at the first day of the experiment, to (0–2,000 mg L -1 ) at the end of the experiment after gradual Pb additions after every sample collecting day. Methods used for analysing the plant material: the content of amino acid proline and photosynthetic pigments were determined by spectrophotometry; chlorophyll a fluorescence parameters – using continuous excitation chlorophyll fluorimeter. The fresh weight of plant above-ground parts and roots was detected. The growth and development of field beans was slightly influenced by increasing amount of Cd and Pb in substrate only at the end of the experiment. The highest Cd treatments (Cd20 and Cd25) caused 2.5 and 1.3 times increased proline concentration in bean leaves. The chlorophyll a + b content and chlorophyll a fluorescence parameter Fv/Fm changed differently throughout the experiment. In general, during the experiment, there was a tendency for the content of proline in leaves for Pb treatments to be increased compared to control. At the end of the experiment the content of proline in field bean leaves of the highest Pb treatments (Pb600 + 100 + 400 + 500, Pb800 + 100 + 400 + 500 and Pb 1,000 + 100 + 400 + 500) was 1.66, 1.44 and 1.55 times higher, respectively, than that of the control plant leaves. The negative impact of exposure to Pb on chlorophyll a + b, chlorophyll a fluorescence parameter PIndex and Fv/Fm in bean leaves was less pronounced compared to Cd. The obtained results confirm that field beans until their flowering stage can grow and develop in the presence of a large amount of Cd and Pb in substrate without significant growth inhibition and detrimental impact on physiological parameters, if optimal cultivation conditions are provided

BOLD Noise Assumptions in fMRI

This paper discusses the assumption of Gaussian noise in the blood-oxygenation-dependent (BOLD) contrast for functional MRI (fMRI). In principle, magnitudes in MRI images follow a Rice distribution. We start by reviewing differences between Rician and Gaussian noise. An analytic expression is derived for the null (resting-state) distribution of the difference between two Rician distributed images. This distribution is shown to be symmetric, and an exact expression for its standard deviation is derived. This distribution can be well approximated by a Gaussian, with very high precision for high SNR, and high precision for lower SNR. Tests on simulated and real MR images show that subtracting the time-series mean in fMRI yields asymmetrically distributed temporal noise. Subtracting a resting-state time series from the first results in symmetric and nearly Gaussian noise. This has important consequences for fMRI analyses using standard statistical tests

Effect of COVID vaccination on monthly migraine days:a longitudinal cohort study

BACKGROUND: This longitudinal cohort study aimed to investigate changes in migraine-related outcomes following COVID-19 infection and vaccination. METHODS: We identified 547 clinically diagnosed migraine patients from the Leiden Headache Center who kept a headache E-diary during the COVID-19 pandemic (February 2020 to August 2022). We sent a questionnaire to register their COVID-19 infection and/or vaccination dates. After applying inclusion criteria, n = 59 participants could be included in the infection analysis and n = 147 could be included in the vaccination analysis. Primary outcome was the change in monthly migraine days (MMD) between 1 month prior and 1 month post COVID-19 infection or vaccination. Secondary outcome variables were change in monthly headache days (MHD) and monthly acute medication days (MAMD). RESULTS:Vaccination against COVID-19 was associated with an increase in MMD (1.06; 95% confidence interval [CI] = 0.57-1.55; p &lt; 0.001), MHD (1.52; 95% CI = 0.91-2.14; p &lt; 0.001) and MAMD (0.72; 95% CI = 0.33-1.12; p &lt; 0.001) in the first month post-vaccination. COVID-19 infection solely increased the number of MAMD (1.11; 95% CI = 0.10-1.62; p &lt; 0.027), but no statistically significant differences in MMD or MHD were observed. CONCLUSIONS: Our findings imply that vaccination against COVID-19 is associated with an increase in migraine, indicating a possible role of inflammatory mediators in migraine pathophysiology.</p

Multichannel interference mitigation methods in radio astronomy

Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language, and give an introduction to some elementary algorithms from that field. We consider two topics in detail: interference detection by rank estimation of short-term covariance matrices, and spatial filtering by subspace estimation and projection. We discuss experimental data collected at the Westerbork radio telescope, and illustrate the effectiveness of the space-time detection and blanking process on the recovery of a 3C48 absorption line in the presence of GSM mobile telephony interference.Comment: 39 pages, 18 figures.Enhanced figures can be downloaded from http://cas.et.tudelft.nl/~leshem/postscripts/leshem/figs34567.ps.gz To appear in Astrophysical Journal Supplements serie