Crop Physiology of Cannabis sativa L.: A Simulation Study of Potential Yield of Hemp in Northwest Europe

1999 ◽  
pp. 101-124
Keyword(s):  
Simulation Study ◽  
Cannabis Sativa ◽  
Potential Yield ◽  
Crop Physiology ◽  
Northwest Europe

scholarly journals Yield of new hemp varieties for medical purposes under semi-arid Mediterranean environment conditions

2020 ◽  
Vol 11 ◽  
pp. e3264
Author(s):  
Iván Francisco García-Tejero ◽  
Almudena Hernández ◽  
Carlos Ferreiro-Vera ◽  
Victor Hugo Durán Zuazo ◽  
Jesus Hidalgo García ◽  
...  
Keyword(s):  
Biomass Production ◽  
Plant Density ◽  
Cannabis Sativa ◽  
Mediterranean Area ◽  
Potential Yield ◽  
Active Biomass ◽  
Mediterranean Countries ◽  
Plant Densities ◽  
Agricultural Areas ◽  
Semi Arid

Under the effects of climate change new drought tolerant crops are imperative to introduce in irrigated agricultural areas of Mediterranean countries. In this sense, hemp (Cannabis sativa L.) represents an alternative in many semi-arid agricultural areas of Mediterranean basin because of its low water requirements and cost effectiveness when it is developed under non controlled conditions. The aim of this work was to evaluate the potential yield of five new hemp varieties (Sara, Pilar, Aida, Theresa, and Juani) cultivated under high tunnel conditions in a semi-arid Mediterranean area, and also to study the effect of plant density on active biomass production and cannabinoids biosynthesis (cannabidiol, CBD and cannabigerol, CBG) at different plant positions. The trial was conducted under plastic macro-tunnels during two seasons (2014 and 2015), from May to October. The agronomic response and the chemical profiles of the studied varieties were evaluated at the end of each season. Moreover, it was monitored the differentiation in terms of active biomass production and cannabinoids biosynthesis in different plant organ positions (at upper, medium, and lower). Additionally, during the second season, three different plant densities (PD1, 9,777; PD2, 7,333; and PD3, 5,866 plants· ha-1) were tested in order to define the the best of them for maximizing CBD and CBG productions. The findings highlighted significant differences in yield between cultivars within the CBD and CBG. Moreover, plant density was a determinant factor related to active biomass production and cannabinoids contents, PD3 representing a suitable strategy to maximize the cannabinoids production minimizing the requirements of rooted apical cuttings. These results allowed concluding that these new hemp cultivars together with the adopted agronomic practices in this experience would be very appropriate for CBD and CBG productions, being determinant to consider the plant density and the cultivar for both studied chemotypes.

Cannabis und Schizophrenie

2002 ◽  
Vol 48 (5) ◽  
pp. 336-345 ◽  
Author(s):  
Jürgen Seifert ◽  
Jann Schlimme ◽  
Felix Wedegärtner ◽  
Hinderk M. Emrich ◽  
Udo Schneider
Keyword(s):  
Cannabis Sativa ◽  
Cannabinoid System ◽  
Psychotische Störungen

Überblick: Cannabis sativa ist eine der ältesten medizinischen Heilpflanzen. In den westlichen Kulturen wird Cannabis überwiegend als Freizeitdroge angesehen. Im Harz sowie in den Blüten der weiblichen Pflanze findet sich ein Gemisch aus verschiedenen psychoaktiven Inhaltsstoffen. Am bedeutendsten ist in diesem Zusammenhang das delta-9-Tetrahy-drocannabinol. </P><P> Epidemiologie: Nicht selten werden die Gefahren des Cannabiskonsums, wie z. B. die Möglichkeit der Induktion einer Psychose unterschätzt. Wenn man jedoch berücksichtigt, wie häufig z. B. Jugendliche THC konsumieren, ist die Frage, ob Cannabis eine Psychose aus dem schizophrenen Formenkreis de novo induzieren kann, von besonderem gesundheitspolitischem und volkswirtschaftlichem Interesse. Die Datenlage ist allerdings nach wie vor unklar. Die klinisch-epidemiologischen Studien deuten aber darauf hin, dass Cannabiskonsum bei vulnerablen Personen schizophrenieforme Psychosen auslösen kann und einen ungünstigen Krankheitsverlauf zur Folge hat. </P><P> Das endogene Cannabinoid-System: Die vorliegende Arbeit gibt außerdem einen Überblick der Publikationen, die sich mit dem körpereigenen Cannabinoid- System und seinen endogenen Liganden im Hinblick auf psychotische Störungen beschäftigen.

An Alternative to Cohen's κ

2006 ◽  
Vol 11 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Alexander von Eye
Keyword(s):  
Simulation Study ◽  
Null Hypothesis ◽  
Categorical Variables ◽  
Alternative Measure ◽  
Rater Agreement ◽  
Verbal Processing ◽  
Heavy Tailed ◽  
Applicant Selection

At the level of manifest categorical variables, a large number of coefficients and models for the examination of rater agreement has been proposed and used. The most popular of these is Cohen's κ. In this article, a new coefficient, κ s , is proposed as an alternative measure of rater agreement. Both κ and κ s allow researchers to determine whether agreement in groups of two or more raters is significantly beyond chance. Stouffer's z is used to test the null hypothesis that κ s = 0. The coefficient κ s allows one, in addition to evaluating rater agreement in a fashion parallel to κ, to (1) examine subsets of cells in agreement tables, (2) examine cells that indicate disagreement, (3) consider alternative chance models, (4) take covariates into account, and (5) compare independent samples. Results from a simulation study are reported, which suggest that (a) the four measures of rater agreement, Cohen's κ, Brennan and Prediger's κ n , raw agreement, and κ s are sensitive to the same data characteristics when evaluating rater agreement and (b) both the z-statistic for Cohen's κ and Stouffer's z for κ s are unimodally and symmetrically distributed, but slightly heavy-tailed. Examples use data from verbal processing and applicant selection.

Comparison of Principal Component Solutions in Two Populations

Methodology ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Gregor Sočan
Keyword(s):  
Simulation Study ◽  
Principal Components ◽  
Common Factor ◽  
Principal Component ◽  
Component Model ◽  
Bootstrap Procedure ◽  
Factor Loadings ◽  
Component Loadings ◽  
Principal Component Model ◽  
Two Populations

Abstract. When principal component solutions are compared across two groups, a question arises whether the extracted components have the same interpretation in both populations. The problem can be approached by testing null hypotheses stating that the congruence coefficients between pairs of vectors of component loadings are equal to 1. Chan, Leung, Chan, Ho, and Yung (1999) proposed a bootstrap procedure for testing the hypothesis of perfect congruence between vectors of common factor loadings. We demonstrate that the procedure by Chan et al. is both theoretically and empirically inadequate for the application on principal components. We propose a modification of their procedure, which constructs the resampling space according to the characteristics of the principal component model. The results of a simulation study show satisfactory empirical properties of the modified procedure.

Assessing Person Fit With the Information Matrix Test

Methodology ◽  
2015 ◽  
Vol 11 (1) ◽  
pp. 3-12 ◽  
Author(s):  
Jochen Ranger ◽  
Jörg-Tobias Kuhn
Keyword(s):  
Simulation Study ◽  
Type I Error ◽  
Information Matrix ◽  
Small Samples ◽  
Type I ◽  
Person Fit ◽  
Power Of The Test ◽  
Order Expansion ◽  
Trait Stability ◽  
Information Matrix Test

In this manuscript, a new approach to the analysis of person fit is presented that is based on the information matrix test of White (1982) . This test can be interpreted as a test of trait stability during the measurement situation. The test follows approximately a χ2-distribution. In small samples, the approximation can be improved by a higher-order expansion. The performance of the test is explored in a simulation study. This simulation study suggests that the test adheres to the nominal Type-I error rate well, although it tends to be conservative in very short scales. The power of the test is compared to the power of four alternative tests of person fit. This comparison corroborates that the power of the information matrix test is similar to the power of the alternative tests. Advantages and areas of application of the information matrix test are discussed.

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