678 research outputs found
Application of accelerated heteronuclear single quantum coherence experiments to the rapid quantification of monosaccharides and disaccharides in dairy products
Monosaccharides and disaccharides are important dietary components, but if insufficiently metabolized by some population subgroups, they are also linked to disease patterns. Thus, the correct analytical identification, quantification, and labeling of these food components are crucial to inform and potentially protect consumers. Enzymatic assays and high-performance anion-exchange chromatography with pulsed amperometric detection are established methods for the quantification of monosaccharides and disaccharides that, however, require long measuring times (60–180 min). Accelerated methods for the identification and quantification of the nutritionally relevant monosaccharides and disaccharides d-glucose, d-galactose, d-fructose, sucrose, lactose, and maltose were therefore developed. To realize this goal, the NMR experiments HSQC (heteronuclear single quantum coherence) and acceleration by sharing adjacent polarization (ASAP)-HSQC were applied. Measurement times were reduced to 27 and 6 min, respectively, by optimizing the interscan delay and applying non-uniform sampling. The optimized methods were used to quantify d-glucose, d-galactose, d-fructose, sucrose, and lactose in various dairy products. Results of the HSQC and ASAP-HSQC methods are equivalent to the results of the reference methods in terms of both precision and accuracy, demonstrating that these methods can be used to correctly analyze nutritionally relevant monosaccharides and disaccharides in short times
Impact of earthworm activity on the chemical fertility of irrigated soil with urban effluents
The reuse of urban effluents to irrigate the soils of peri-urban grasslands in the vicinity of the town of Setif (northeastern Algeria) is an old and widespread practice. In this context, the present study was conducted to evaluate the effect of the irrigation with urban effluents on the biological and chemical behavior of soils. Effluents analysis showed significant organic and particulate pollution, the latter contributed to earthworm abundance and increased the richness of irrigated soils with nutrients. The analysis of turricules revealed the role of earthworms through the activity of bioturbation in the increase of the rate of organic matter as well as in the bioavailability of the nutrients of the irrigated soils. In space, permanent vegetation cover has played an important role as a biofilter. This was confirmed by the inter-site differences recorded through the measured variables particularly organic ones.Keywords: Natural grasslands, urban effluents, earthworm activity, turricles, organic matte
Covariants,joint invariants and the problem of equivalence in the invariant theory of Killing tensors defined in pseudo-Riemannian spaces of constant curvature
The invariant theory of Killing tensors (ITKT) is extended by introducing the
new concepts of covariants and joint invariants of (product) vector spaces of
Killing tensors defined in pseudo-Riemannian spaces of constant curvature. The
covariants are employed to solve the problem of classification of the
orthogonal coordinate webs generated by non-trivial Killing tensors of valence
two defined in the Euclidean and Minkowski planes. Illustrative examples are
provided.Comment: 60 pages. to appear in J. Math. Phy
Experiments with urea on private farms
Many District Advisers have carried out trials on private farms to test the response to a variety of types of supplementary feeds. This report gives brief details of five such experiments carried out with urea supplements over the last five years. Table 1 summarises the details and results of these trials
Speech Audio Synthesis from Tagged MRI and Non-Negative Matrix Factorization via Plastic Transformer
The tongue's intricate 3D structure, comprising localized functional units,
plays a crucial role in the production of speech. When measured using tagged
MRI, these functional units exhibit cohesive displacements and derived
quantities that facilitate the complex process of speech production.
Non-negative matrix factorization-based approaches have been shown to estimate
the functional units through motion features, yielding a set of building blocks
and a corresponding weighting map. Investigating the link between weighting
maps and speech acoustics can offer significant insights into the intricate
process of speech production. To this end, in this work, we utilize
two-dimensional spectrograms as a proxy representation, and develop an
end-to-end deep learning framework for translating weighting maps to their
corresponding audio waveforms. Our proposed plastic light transformer (PLT)
framework is based on directional product relative position bias and
single-level spatial pyramid pooling, thus enabling flexible processing of
weighting maps with variable size to fixed-size spectrograms, without input
information loss or dimension expansion. Additionally, our PLT framework
efficiently models the global correlation of wide matrix input. To improve the
realism of our generated spectrograms with relatively limited training samples,
we apply pair-wise utterance consistency with Maximum Mean Discrepancy
constraint and adversarial training. Experimental results on a dataset of 29
subjects speaking two utterances demonstrated that our framework is able to
synthesize speech audio waveforms from weighting maps, outperforming
conventional convolution and transformer models.Comment: MICCAI 2023 (Oral presentation
Critical review of methods for risk ranking of food related hazards, based on risks for human health.
This study aimed to critically review methods for ranking risks related to food safety and dietary hazards on the basis of their anticipated human health impacts. A literature review was performed to identify and characterize methods for risk ranking from the fields of food, environmental science and socio-economic sciences. The review used a predefined search protocol, and covered the bibliographic databases Scopus, CAB Abstracts, Web of Sciences, and PubMed over the period 1993-2013. All references deemed relevant, on the basis of of predefined evaluation criteria, were included in the review, and the risk ranking method characterized. The methods were then clustered - based on their characteristics - into eleven method categories. These categories included: risk assessment, comparative risk assessment, risk ratio method, scoring method, cost of illness, health adjusted life years, multi-criteria decision analysis, risk matrix, flow charts/decision trees, stated preference techniques and expert synthesis. Method categories were described by their characteristics, weaknesses and strengths, data resources, and fields of applications. It was concluded there is no single best method for risk ranking. The method to be used should be selected on the basis of risk manager/assessor requirements, data availability, and the characteristics of the method. Recommendations for future use and application are provided
Superrotation in a Venus general circulation model
A superrotating atmosphere with equatorial winds of ~ 35 ms-1 is simulated using a
simplified Venus general circulation model (GCM). The equatorial superrotation in the
model atmosphere is maintained by barotropic instabilities in the midlatitude jets
which transport angular momentum toward the equator. The midlatitude jets are
maintained by the mean meridional circulation, and the momentum transporting waves are
qualitatively similar to observed midlatitude waves; an equatorial Kelvin wave is also
present in the atmosphere. The GCM is forced by linearized cooling and friction
parameterizations, with hyperdiffusion and a polar Fourier filter to maintain numerical
stability. Atmospheric superrotation is a robust feature of the model and is spontaneously
produced without specific tuning. A strong meridional circulation develops in the form
of a single Hadley cell, extending from the equator to the pole in both hemispheres, and
from the surface to 50 km altitude. The zonal jets produced by this circulation reach
45 ms-1 at 60 km, with peak winds of 35 ms-1 at the equator. A warm pole and cold
collar are also found in the GCM, caused by adiabatic warming in the mean
meridional circulation. Wave frequencies and zonal wind speeds are smaller than in
observations by cloud tracking but are consistent with a Doppler shifting by wind speeds
in the generating region of each wave. Magnitudes of polar temperature anomalies are
smaller than the observed features, suggesting dynamical processes alone may not
be sufficient to maintain the large observed temperature contrasts at the
magnitudes and periods found in this GCM
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