4,576 research outputs found
An Angiosperm species dataset reveals relationships between seed size and two-dimensional shape
Datasets containing information on seed size have been published and are currently available. Nevertheless, there is a lack in the literature of a dataset dedicated to seed shape. We present a preliminary version for a dataset on seed morphology based on a comparison of seed shape with geometric figures. Similarity of the outline of seed images with geometric models is considered as a basis to classify seeds according to the geometric figures they resemble (e.g., ellipse, oval, cardioid). This allows, first, the classification of plant species according to their geometric type of seed, and second, seed shape quantification. For each seed image, the percent of similarity of their outline with a geometric figure can be calculated as a J index. Similarity in absolute terms is considered only when the J index >90. This criterion is important to avoid ambiguity and increase discrimination. The dataset opens the possibility of studying the relationship between seed shape and other variables such as seed size, genome complexity, life form or adaptive responses
Pet Loss and Grieving Strategies: A Systematic Review of Literature
The impact that companion animals have on human lives has been explored in many aspects including therapy and emotional support. In some cases, these types of pets have been deemed necessary for pet owners with medical problems. However, pets are not only a medical necessity for some humans, but they are also companions, and most are included as family members. The loss of a pet often brings on intense grief that is not often acknowledged in the workforce. Bereavement leave for immediate family members is a benefit offered to employees, and as we will read in this literature review pet owners grieve the loss of a pet even more so than a human family. It would only make sense to include pets in this policy. Companies that include this benefit have improved employee morale, retention rates, company loyalty, and less stress. (Shutan, 2017
Ermakov Systems with Multiplicative Noise
Using the Euler-Maruyama numerical method, we present calculations of the
Ermakov-Lewis invariant and the dynamic, geometric, and total phases for
several cases of stochastic parametric oscillators, including the simplest case
of the stochastic harmonic oscillator. The results are compared with the
corresponding numerical noiseless cases to evaluate the effect of the noise.
Besides, the noiseless cases are analytic and their analytic solutions are
briefly presented. The Ermakov-Lewis invariant is not affected by the
multiplicative noise in the three particular examples presented in this work,
whereas there is a shift effect in the case of the phasesComment: 12 pages, 4 figures, 22 reference
Remark on charge conjugation in the non relativistic limit
We study the non relativistic limit of the charge conjugation operation in the context of the Dirac equation coupled to an electromagnetic field.
The limit is well defined and, as in the relativistic case, ,
(parity) and (time reversal) are the generators of a matrix group
isomorphic to a semidirect sum of the dihedral group of eight elements and
. The existence of the limit is supported by an argument based in quantum
field theory. Also, and most important, the limit exists in the context of
galilean relativity. Finally, if one complexifies the Lorentz group and
therefore the galilean spacetime , then the explicit form of the matrix
for allows to interpret it, in this context, as the complex
conjugation of the spatial coordinates: . This result is
natural in a fiber bundle description.Comment: 8 page
Genetic and Molecular Characterization of Temperate and Tropical Forage Maize Inbred Lines
The livestock feeding in the Central highland of Mexico is based on harvest, grazing and annual forage conservation, being forage maize the most important silage crop (Alarcón, 1995). Even though forage maize is extensively bred in Europe, USA and Asia since 1900\u27s, this started in Mexico in the 1960\u27s, and little is known about the genetic diversity in both agronomic and nutritive value traits. Our breeding program goals are to analyze combining ability of biomass and quality predictors and to study the genetic relationship of inbred lines between lowland tropical and temperate races from Mesa Central, by genetic and molecular approaches
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