Optimal Matching Distances between Categorical Sequences: Distortion and Inferences by Permutation

Sequence data (an ordered set of categorical states) is a very common type of data in Social Sciences, Genetics and Computational Linguistics. For exploration and inference of sets of sequences, having a measure of dissimilarities among sequences would allow the data to be analyzed by techniques like clustering, multimensional scaling analysis and distance-based regression analysis. Sequences can be placed in a map where similar sequences are close together, and dissimilar ones will be far apart. Such patterns of dispersion and concentration could be related to other covariates. For example, do the employment trajectories of men and women tend to form separate clusters? Optimal Matching (OM) distances have been proposed as a measure of dissimilarity between sequences. Assuming that sequences are empirical realizations of latent random objects, this thesis explores how good the fit is between OM distances and original distances between the latent objects that generated the sequences, and the geometrical nature of such distortions. Simulations show that raw OM dissimilarities are not an exact mirror of true distances and show systematic distortions. Common values for OM substitution and insertion/deletion costs produce dissimilarities that are metric, but not Euclidean. On the other hand, distances can be easily transformed to be Euclidean. If differing values of a covariate lead to different latent random objects and thus different sequences, are there tests with enough power to catch such variability, among the natural intersequence random variation? Such tests should be robust enough to cope with the non-euclideanity of OM distances. A number of statistical tests (Permutational MANOVA, MRPP, Mantel’s correlation, and t-tests and median tests) were compared for statistical power, on associations between inter-item dissimilarities and a categorical explanatory variable. This thesis shows analytically that under simple conditions, the first four tests are mathematically equivalent. Simulations confirmed that tests had the same power. Tests are less powerful with longer sequences

Induction of stimulative parthenocarpy in Vitis vinifera L.

Stimulative parthenocarpy was induced in two varieties of Vitis vinifera L. Flame Tokay and Rose Muscat (local variety) out of eight varieties studied.In F l a m e T o k a y the delay or inhibition of bhe abscission of the calyptra and parthenocarpic development of the berries, was obtained with pre-bloom treatments (3 days before beginning of bloom) of 4CPA 30 ppm + KGA3 30 ppm. Induction and growth ,of parthenocarpic berries was most pronounced after post-bloom sprays (7 days after the end of bloom) with BA 1500 ppm + KGA3 80 ppm or 4CPA 30 ppm. A parthenocarpic development of the berries was also obtained with postbloom treatments of KGA3 at concentrations of 50 to 100 ppm. BA (Benzyladenine) alone had only a slight effect on the development of parthenocarpic berries. However, the results were surprisingly satisfactory when applied in combination with gibberellin (KGA3 80 ppm) or auxins. Treatments at bloom or after bloom with BA 800 ppm + KGA3 80 ppm increased bhe number of berries and cluster weight. Applications of BA 800 ppm + KGA3 80 ppm to Rose Musca t at the beginning of bloom resulted in clusters with practically all berries seedless. The artificially accelerated growth of the berries may provoke abortion of all the recently fecundated ovules and the non viability of the not fecundated ones. Clusters of the treated plants with an average of 520 flowers originated 501 parbhenocarpic berries (96%), whereas the control with an average 635 flowers per cluster gave a percentage of seeded + seedless berries of 14% only {95 berries per cluster). BA applied with auxin or gibberellin-like substances in full-bloom or after bloom produced seedless berries, which were smaller in size than the seeded berries of unsprayed clusters

The Spin-Orbit Evolution of GJ 667C System: The Effect of Composition and Other Planet's Perturbations

Potentially habitable planets within the habitable zone of M-dwarfs are affected by tidal interaction. We studied the tidal evolution in GJ 667C using a numerical code we call TIDEV. We reviewed the problem of the dynamical evolution focusing on the effects that a rheological treatment, different compositions and the inclusion of orbital perturbations, have on the spin-down time and the probability to be trapped in a low spin-orbit resonance. Composition have a strong effect on the spin-down time, changing, in some cases, by almost a factor of 2 with respect to the value estimated for a reference Earth-like model. We calculated the time to reach a low resonance value (3:2) for the configuration of 6 planets. Capture probabilities are affected when assuming different compositions and eccentricities variations. We chose planets b and c to evaluate the probabilities of capture in resonances below 5:2 for two compositions: Earth-like and Waterworld planets. We found that perturbations, although having a secular effect on eccentricities, have a low impact on capture probabilities and noth- ing on spin-down times. The implications of the eccentricity variations and actual habitability of the GJ 667C system are discussed.Comment: 15 pages, 9 figures, 4 tables. Accepted for publication in MNRAS - V

Rumour Processes on N

We study four discrete time stochastic systems on \bbN modeling processes of rumour spreading. The involved individuals can either have an active or a passive role, speaking up or asking for the rumour. The appetite in spreading or hearing the rumour is represented by a set of random variables whose distributions may depend on the individuals. Our goal is to understand - based on those random variables distribution - whether the probability of having an infinite set of individuals knowing the rumour is positive or not

Planeamiento de la expansión de sistemas de transmisión de energía eléctrica considerando contingencias

En este artículo se presenta una metodología y un modelo matemático que da solución al problema del planeamiento de la expansión cuando se considera desde la etapa del planeamiento el efecto de las contingencias. Se emplea el modelo de flujo de carga DC para representar la red eléctrica. El problema del planeamiento de la expansión puede ser dividido en dos subproblemas, un subproblema de inversión y un subproblema operativ

The Spin-Orbit Evolution of GJ 667C System: The Effect of Composition and Other Planet’s Perturbations

Potentially habitable planets within the habitable zone of M dwarfs are affected by tidal interaction. We studied tidal evolution in GJ 667C using a numerical code we call TIDEV. We reviewed the problem of dynamical evolution, focusing on the effects of a rheological treatment, different compositions and the inclusion of orbital perturbations on the spin-down time and the probability of becoming trapped in a low spin-orbit resonance. The composition has a noticeable effect on the spin-down time, which changes, in some cases, by almost a factor of 2 with respect to the value estimated for a reference Earth-like model. We calculated the time required to reach a low resonance value (3:2) for a configuration of six planets. Capture probabilities are affected when assuming different compositions and eccentricity variations. We chose planets b and c to evaluate the probabilities of capture in resonances below 5:2 for two compositions: Earth-like and Waterworld planets. We found that perturbations, although having a secular effect on eccentricities, have a low impact on capture probabilities and no effect on spin-down times. The implications of the eccentricity variations and actual habitability of the GJ 667C system are discussed.Facultad de Ciencias Astronómicas y Geofísica

Planeamiento de la expansión de sistemas de transmisión de energía eléctrica considerando contingencias

En este artículo se presenta una metodología y un modelo matemático que da solución al problema del planeamiento de la expansión cuando se considera desde la etapa del planeamiento el efecto de las contingencias. Se emplea el modelo de flujo de carga DC para representar la red eléctrica. El problema del planeamiento de la expansión puede ser dividido en dos subproblemas, un subproblema de inversión y un subproblema operativ

Chirping compact stars: gravitational radiation and detection degeneracy with binary systems A conceptual pathfinder for space-based gravitational-wave observatories

Compressible, Riemann S-type ellipsoids can emit gravitational waves (GWs) with a chirp-like behavior (hereafter chirping ellipsoids, CELs). We show that the GW frequency-amplitude evolution of CELs (mass $\sim 1$~M$_\odot$, radius $\sim10^3$~km, polytropic equation of state with index $n\approx 3$) is indistinguishable from that emitted by double white dwarfs (DWDs) and by extreme mass-ratio inspirals (EMRIs) composed of an intermediate-mass (e.g.~$10^3~M_\odot$) black hole and a planet-like (e.g.~$10^{-4}~M_\odot$) companion, in a specific frequency interval within the detector sensitivity band in which the GWs of all these systems are quasi-monochromatic. We estimate that for reasonable astrophysical assumptions, the rates in the local Universe of CELs, DWDs and EMRIs in the mass range considered here, are very similar, posing a detection-degeneracy challenge for space-based GW detectors. The astrophysical implications of this CEL-binary detection degeneracy by space-based GW-detection facilities, are outlined.Comment: Submitted to Phys. Rev.