Search results for "principal"
showing 10 items of 795 documents
Phenolic profiles of raw mono- and polyfloral honeys from Latvia
2021
Abstract The phenolic compound profiles of 393 raw mono- and polyfloral Latvian honey samples were investigated using a targeted ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) method. This strategy allowed simultaneous determination of the content of 11 phenolic acids, 18 flavonoids, 2 plant hormones, and 3 water-soluble vitamins in honey samples of botanically diverse origin, including buckwheat (Fagopyrum esculentum), heather (Calluna vulgaris), linden (Tilia cordata), and rapeseed (Brassica napus). Honey samples were collected directly from the beekeepers and were analyzed in their natural, raw form. A selective high-throughput analysis was im…
Chemometrics as a Tool of Origin Determination of Polish Monofloral and Multifloral Honeys
2014
The aim of this study was to evaluate the application of chemometrics studies to determine the botanical origin of Polish monofloral honeys using NMR spectroscopy. Aqueous extracts of six kinds of honeys, namely, heather (Calluna vulgaris L.), buckwheat (Fagopyrum esculentum L), lime (Tilia L), rape (Brassica napus L. var. napus), acacia (Acacia Mill.), and multifloral ones, were analyzed. Multivariate chemometric data analysis was performed using principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLS-DA). Chemometric analysis supported by pollen analysis revealed the incorrect classification of acacia honeys by the producers. Characteristic moti…
Selection and Gratitude: Anonymity and gratitude
2018
What kind of candidate is selected into a job when the principal has to appoint a committee to measure the candidate's ability and select a winner through a call specifying a wage for the job? In a model where the principal fixes the wage anticipating the committee's choice, under a rather natural assumption about the committee's objective we find that if the committee takes into account the candidate's gratitude a candidate with less than first best ability will be selected in equilibrium. First best selection is achieved if the committee is anonymous to the candidates. If the committee could also set the wage the first best candidate would be selected, but the principal would be worse off…
Extensive phytocannabinoid profiles of seized cannabis and cannabis-based medicines – Identification of potential distinguishing markers
2021
As the frequency of cannabis-based therapy increases, the ability to distinguish intake of cannabis-based medicines from recreational cannabis use becomes desirable. Minor cannabinoids have been suggested to indicate recreational cannabis use in biological matrices but are unreliable when presumably also present in directly plantderived medicines. Thus, for therapeutics such as medical cannabis, Sativex® and Dronabinol, a more thorough investigation of cannabinoid profiles is required to identify possible distinguishing markers. In this study, 16 phytocannabinoids were quantified in samples of seized and medical cannabis, Sativex® and Dronabinol from two different manufacturers, using a val…
Identification of Potential Distinguishing Markers for the Use of Cannabis-Based Medicines or Street Cannabis in Serum Samples
2021
Increasing prescription numbers of cannabis-based medicines raise the question of whether uptake of these medicines can be distinguished from recreational cannabis use. In this pilot study, serum cannabinoid profiles after use of cannabis-based medicines were investigated, in order to identify potential distinguishing markers. Serum samples after use of Sativex®, Dronabinol or medical cannabis were collected and analyzed for 18 different cannabinoids, using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Analytes included delta-9-tetrahydrocannabinol, 11-hydroxy-tetrahydrocannabinol, 11-nor-9-carboxy-tetrahydrocannabinol, cannabidiol, cannabinol, cannabigerol, …
L-band vegetation optical depth seasonal metrics for crop yield assessment
2018
Attenuation of surface microwave emission due to the overlying vegetation is proportional to the density of the canopy and to its water content. The vegetation optical depth (VOD) parameter measures this attenuation. VOD could be a valuable source of information on agroecosystems, especially at lower frequencies for which greater portion of the vegetation canopy contributes to the observed brightness temperature. In the past, visible-infrared indices have been used to provide yield estimates based on measuring the photosynthetic activity from the surface canopy layer. These indices are affected by clouds and apply only in the presence of solar illumination. In this study we instead use the …
Rethinking the sGLOH Descriptor
2018
sGLOH (shifting GLOH) is a histogram-based keypoint descriptor that can be associated to multiple quantized rotations of the keypoint patch without any recomputation. This property can be exploited to define the best distance between two descriptor vectors, thus avoiding computing the dominant orientation. In addition, sGLOH can reject incongruous correspondences by adding a global constraint on the rotations either as an a priori knowledge or based on the data. This paper thoroughly reconsiders sGLOH and improves it in terms of robustness, speed and descriptor dimension. The revised sGLOH embeds more quantized rotations, thus yielding more correct matches. A novel fast matching scheme is a…
Regularity of solutions of cauchy problems with smooth cauchy data
1988
Computational identification of cell-specific variable regions in ChIP-seq data.
2019
ABSTRACT Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is used to identify genome-wide DNA regions bound by proteins. Several sources of variation can affect the reproducibility of a particular ChIP-seq assay, which can lead to a misinterpretation of where the protein under investigation binds to the genome in a particular cell type. Given one ChIP-seq experiment with replicates, binding sites not observed in all the replicates will usually be interpreted as noise and discarded. However, the recent discovery of high-occupancy target (HOT) regions suggests that there are regions where binding of multiple transcription factors can be identified. To investigate these regions,…
Cellular automata and urban development simulation : a transition rules creation process based on statistical analysis
2015
National audience; Nowadays land use evolution study has become a major stake in urban planning. The main focus is to understand the way in which land use evolves across time and to understand processes that take place. This understanding would allow to plan urban developments based on a knowledge as complete as possible covering as many fields as possible (i.e. urban planning, politics, sociology, etc.). Simulation tools can be used to merge and display different points of view and stakes from different stakeholders (Parrott & Meyer, 2012).