Improving Twitter gender classification using multiple classifiers

The user profile information is important for many studies, but essential information, such as gender and age, is not provided when creating a Twitter account. However, clues about the user profile, such as the age and gender, behaviors, and preferences, can be extracted from other content provided by the user. The main focus of this paper is to infer the gender of the user from unstructured information, including the username, screen name, description and picture, or by the user generated content. Our experiments use an English labelled dataset containing 6.5M tweets from 65K users, and a Portuguese labelled dataset containing 5.8M tweets from 58K users. We use supervised approaches, considering four groups of features extracted from different sources: user name and screen name, user description, content of the tweets, and profile picture. A final classifier that combines the prediction of each one of the four previous partial classifiers achieves 93.2% accuracy for English and 96.9% accuracy for Portuguese data.info:eu-repo/semantics/publishedVersio

Creating extended gender labelled datasets of Twitter users

The gender information of a Twitter user is not known a priori when analysing Twitter data, because user registration does not include gender information. This paper proposes an approach for creating extended gender labelled datasets of Twitter users. The process involves creating a smaller database of active Twitter users and to manually label the gender. The process follows by extracting features from unstructured information found on each user profile and by creating a gender classification model. The model is then applied to a larger dataset, thus providing automatic labels and corresponding confidence scores, which can be used to estimate the most accurately labeled users. The resulting databases can be further enriched with additional information extracted, for example, from the profile picture and from the user location. The proposed approach was successfully applied to English and Portuguese users, leading to two large datasets containing more than 57K labeled users each.info:eu-repo/semantics/acceptedVersio

Mutual optical injection in coupled DBR laser pairs

We report an experimental study of nonlinear effects, characteristic of mutual optical coupling, in an ultra-short coupling regime observed in a distributed Bragg reflector laser pair fabricated on the same chip. Optical feedback is amplified via a double pass through a common onchip optical amplifier, which introduces further nonlinear phenomena. Optical coupling has been introduced via back reflection from a cleaveended fibre. The coupling may be varied in strength by varying the distance of the fibre from the output of the chip, without significantly affecting the coupling time. © 2008 Optical. Society of America

Classical Tensors and Quantum Entanglement II: Mixed States

Invariant operator-valued tensor fields on Lie groups are considered. These define classical tensor fields on Lie groups by evaluating them on a quantum state. This particular construction, applied on the local unitary group U(n)xU(n), may establish a method for the identification of entanglement monotone candidates by deriving invariant functions from tensors being by construction invariant under local unitary transformations. In particular, for n=2, we recover the purity and a concurrence related function (Wootters 1998) as a sum of inner products of symmetric and anti-symmetric parts of the considered tensor fields. Moreover, we identify a distinguished entanglement monotone candidate by using a non-linear realization of the Lie algebra of SU(2)xSU(2). The functional dependence between the latter quantity and the concurrence is illustrated for a subclass of mixed states parametrized by two variables.Comment: 23 pages, 4 figure

[OI] disk emission in the Taurus star forming region

The structure of protoplanetary disks is thought to be linked to the temperature and chemistry of their dust and gas. Whether the disk is flat or flaring depends on the amount of radiation that it absorbs at a given radius, and on the efficiency with which this is converted into thermal energy. The understanding of these heating and cooling processes is crucial to provide a reliable disk structure for the interpretation of dust continuum emission and gas line fluxes. Especially in the upper layers of the disk, where gas and dust are thermally decoupled, the infrared line emission is strictly related to the gas heating/cooling processes. We aim to study the thermal properties of the disk in the oxygen line emission region, and to investigate the relative importance of X-ray (1-120 Angstrom) and far-UV radiation (FUV, 912-2070 Angstrom) for the heating balance there. We use [OI] 63 micron line fluxes observed in a sample of protoplanetary disks of the Taurus/Auriga star forming region and compare it to the model predictions presented in our previous work. The data were obtained with the PACS instrument on board the Herschel Space Observatory as part of the Herschel Open Time Key Program GASPS (GAS in Protoplanetary diskS), published in Howard et al. (2013). Our theoretical grid of disk models can reproduce the [OI] absolute fluxes and predict a correlation between [OI] and the sum Lx+Lfuv. The data show no correlation between the [OI] line flux and the X-ray luminosity, the FUV luminosity or their sum. The data show that the FUV or X-ray radiation has no notable impact on the region where the [OI] line is formed. This is in contrast with what is predicted from our models. Possible explanations are that the disks in Taurus are less flaring than the hydrostatic models predict, and/or that other disk structure aspects that were left unchanged in our models are important. ..abridged..Comment: 9 pages, accepted for publication in A&

Tailored graph ensembles as proxies or null models for real networks I: tools for quantifying structure

We study the tailoring of structured random graph ensembles to real networks, with the objective of generating precise and practical mathematical tools for quantifying and comparing network topologies macroscopically, beyond the level of degree statistics. Our family of ensembles can produce graphs with any prescribed degree distribution and any degree-degree correlation function, its control parameters can be calculated fully analytically, and as a result we can calculate (asymptotically) formulae for entropies and complexities, and for information-theoretic distances between networks, expressed directly and explicitly in terms of their measured degree distribution and degree correlations.Comment: 25 pages, 3 figure

Rank one discrete valuations of power series fields

In this paper we study the rank one discrete valuations of the field $k((X_1,..., X_n))$ whose center in k\lcor\X\rcor is the maximal ideal. In sections 2 to 6 we give a construction of a system of parametric equations describing such valuations. This amounts to finding a parameter and a field of coefficients. We devote section 2 to finding an element of value 1, that is, a parameter. The field of coefficients is the residue field of the valuation, and it is given in section 5. The constructions given in these sections are not effective in the general case, because we need either to use the Zorn's lemma or to know explicitly a section $\sigma$ of the natural homomorphism R_v\to\d between the ring and the residue field of the valuation $v$. However, as a consequence of this construction, in section 7, we prove that k((\X)) can be embedded into a field L((\Y)), where $L$ is an algebraic extension of $k$ and the {\em ``extended valuation'' is as close as possible to the usual order function}

Further results on entanglement detection and quantification from the correlation matrix criterion

The correlation matrix (CM) criterion is a recently derived powerful sufficient condition for the presence of entanglement in bipartite quantum states of arbitrary dimensions. It has been shown that it can be stronger than the positive partial transpose (PPT) criterion, as well as the computable cross norm or realignment (CCNR) criterion in different situations. However, it remained as an open question whether there existed sets of states for which the CM criterion could be stronger than both criteria simultaneously. Here, we give an affirmative answer to this question by providing examples of entangled states that scape detection by both the PPT and CCNR criteria whose entanglement is revealed by the CM condition. We also show that the CM can be used to measure the entanglement of pure states and obtain lower bounds for the entanglement measure known as tangle for general (mixed) states.Comment: 13 pages, no figures; added references, minor changes; section 4.3 added, to appear in J. Phys.

Lower calcium and iron intake in adolescent gymnasts: A case of concern for youth sports nutrition.

Diet is important for the appropriate development and maturation of young amateur athletes. The aim of this study was to determine whether young gymnasts were consuming adequate amounts of nutrients, particularly calcium and iron. This cross-sectional survey was conducted in Portugal's Almada and Lisbon regions in 2020. To determine if participants' diet was adequate, weight, height, and skinfold measurements were taken. Dietary consumption was examined using two 24-h recalls. We collected data from 66 participants (60% females, 12-18 y of age), of whom 82% had normal weight and 39% had ideal body fat. The daily total energy intake (TEI) was1605 ± 601 kcal. Of the TEI, 19%, 31%, and 50% were comprised of protein, fat, and carbohydrates, respectively. The most often consumed protein sources were poultry and ultra-processed meat products (52% and 45%, respectively). The average daily consumption of calcium and iron was 626 ± 293 and 9 ± 3 mg, respectively. Only 2 of the 66 participants had calcium intake within recommended levels, and 1of 5 had iron intake within recommended levels, the percentage of which was lower in girls than boys (7.5% versus 38.5%, P < 0.05). Despite having a sufficient macronutrient distribution, Portuguese gymnasts consume a high amount of ultra-processed items and a low amount of calcium and iron. The low proportion of female gymnasts with adequate iron consumption is cause for worry in sports nutrition

Occurrence of subnormal corpus luteum in superovulated Santa Inês sheep using protocols with or without LH administrated at the end of the FSH treatment.

Edição dos Abstracts do II International Symposium on animal Biology or Reproduction, São Paulo, nov. 2008