Ehrhart clutters: Regularity and Max-Flow Min-Cut

If C is a clutter with n vertices and q edges whose clutter matrix has column vectors V={v1,...,vq}, we call C an Ehrhart clutter if {(v1,1),...,(vq,1)} is a Hilbert basis. Letting A(P) be the Ehrhart ring of P=conv(V), we are able to show that if A is the clutter matrix of a uniform, unmixed MFMC clutter C, then C is an Ehrhart clutter and in this case we provide sharp bounds on the Castelnuovo-Mumford regularity of A(P). Motivated by the Conforti-Cornuejols conjecture on packing problems, we conjecture that if C is both ideal and the clique clutter of a perfect graph, then C has the MFMC property. We prove this conjecture for Meyniel graphs, by showing that the clique clutters of Meyniel graphs are Ehrhart clutters. In much the same spirit, we provide a simple proof of our conjecture when C is a uniform clique clutter of a perfect graph. We close with a generalization of Ehrhart clutters as it relates to total dual integrality.Comment: Electronic Journal of Combinatorics, to appea

COCAINE SEIZURES AND CRIME: DATA ANALYTICS USING BIG DATA TOOLS

Includes Supplementary MaterialColombia's status as the largest cocaine producer in the world has prompted its government's strategies to combat drug trafficking. One of these strategies is to seize cocaine in the Colombian jurisdictional territory. The unintended consequences of this strategy on crime rates, particularly homicides, remain uncertain. Web scraping methods and big data tools were used to gather and construct a time series dataset on cocaine seizures from three distinct websites, while the homicides dataset was supplied by the Colombian Ministry of Defense (MDN). This study aims to investigate, from a quantitative standpoint, whether there is a link between cocaine seizures and homicides in the Colombian Pacific region, utilizing an exploratory data analysis (EDA) method and machine learning techniques. The study recognizes the constraints of the sample size and opts to reveal valuable insights through data analysis and modeling instead. Despite the constraints, two models were developed to partially explicate the significance of this correlation. The study's findings provide value for policymakers, military personnel, government officials, and academics, offering essential perspectives to devise improved policies and strategies to mitigate drug trafficking in the Colombian Pacific region without exacerbating homicide rates. Future research endeavors could consider expanding the sample size of the cocaine seizure time-series dataset to conduct a more robust correlation analysis.Approved for public release. Distribution is unlimited.Outstanding ThesisCapitan de Corbeta, Colombian National Nav

Communications

A letter to the editor is presented in response to the article The Georgia Confederate Flag Dispute, by J. Michael Martinez in the summer 2008 issue along with the response of the author

Fast Disparity Estimation from a Single Compressed Light Field Measurement

The abundant spatial and angular information from light fields has allowed the development of multiple disparity estimation approaches. However, the acquisition of light fields requires high storage and processing cost, limiting the use of this technology in practical applications. To overcome these drawbacks, the compressive sensing (CS) theory has allowed the development of optical architectures to acquire a single coded light field measurement. This measurement is decoded using an optimization algorithm or deep neural network that requires high computational costs. The traditional approach for disparity estimation from compressed light fields requires first recovering the entire light field and then a post-processing step, thus requiring long times. In contrast, this work proposes a fast disparity estimation from a single compressed measurement by omitting the recovery step required in traditional approaches. Specifically, we propose to jointly optimize an optical architecture for acquiring a single coded light field snapshot and a convolutional neural network (CNN) for estimating the disparity maps. Experimentally, the proposed method estimates disparity maps comparable with those obtained from light fields reconstructed using deep learning approaches. Furthermore, the proposed method is 20 times faster in training and inference than the best method that estimates the disparity from reconstructed light fields

team UTB-NLP at finances 2023: financial targeted sentiment analysis using a phonestheme semantic approach

Sentiment analysis in the financial domain is a challenging task that plays a crucial role in understanding public opinion, monitoring market trends, and assessing the impact of news on economic agents. In this shared task, we address targeted sentiment analysis in the financial domain, focusing on identifying the main economic target in news headlines and determining the sentiment polarity towards such targets. We propose a methodology that combines transformer-based models and phonestheme embeddings to extract meaningful features from the text, which are then used in a support vector machine (SVM) classifier for sentiment classification. Our approach shows promising results, outperforming the baseline with an F1-score of 0.529229 in Task 1. This research contributes to financial sentiment analysis by addressing the complexity of financial language and considering multiple economic agents' perspectives.Universidad Tecnológica de Bolíva

Tortugas fósiles (Testudinoidea, Cryptodira) del Pleistoceno del yacimiento de brea de Talara, Perú

A description of Pleistocene fossil turtles discovered in the Talara Tar Seeps, Tablazos deposits of the northern coast of Peru is provided in this paper. The specimens are mostly fragmentary plates of carapaces and plastra of turtles belonging to two cryptodiran families of the superfamily Testudinoidea, identified to genus level based on measurements and comparisons with extant and fossil taxa and identification of mosaic diagnostic features. Turtles of the Geoemydidae family are the most abundant, with fossil remains attributed to Rhinoclemmys (indeterminate species). Less abundant fossil remains belong to the Testudinidae, with specimens attributed to the genus Chelonoidis (indeterminate species). These fossils show that the northern coast of Peru had ecosystems that supported abundant aquatic and terrestrial turtles (tortoises) during the Pleistocene in areas where they are completely absent today.El presente trabajo proporciona una descripción de las tortugas fósiles del Pleistoceno descubiertas en el yacimiento de brea de Talara, en la costa norte del Perú. La mayoría de los especímenes son fragmentos de placas del caparazón y del plastrón de tortugas pertenecientes a dos familias de criptodiras dentro de la superfamilia Testudinoidea. La familia Geoemydidae es la más abundante con restos fósiles atribuidos a Rhinoclemmys (especie indeterminada). Los restos fósiles menos abundantes pertenecen a Testudinidae, con especímenes atribuidos al género Chelonoidis (especie indeterminada). Estos fósiles muestran que la costa norte del Perú tenía ecosistemas que permitieron la abundancia de tortugas acuáticas y terrestres durante el Pleistoceno, en áreas donde hoy están completamente ausentes

Essence of enterprise crisis and reasons of its appearance

The effect of the electrolyte concentration (NaCl aqueous electrolyte) on the dimensional variations of films of polypyrrole doped with dodecylbenzenesulfonate PPy(DBS) on Pt and Au wires was studied. Any parallel reaction that occurs during the redox polymeric reaction that drives the mechanical actuation, as detected from the coulovoltammetric responses, was avoided by using Pt wires as substrate and controlling the potential limits, thus significantly increasing the actuator lifetime. The NaCl concentration of the electrolyte, when studied by cyclic voltammetry or chronoamperometry, has a strong effect on the performance as well. A maximum expansion was achieved in 0.3 M aqueous solution. The consumed oxidation and reduction charges control the fully reversible dimensional variations: PPy(DBS) films are faradaic polymeric motors. Parallel to the faradaic exchange of the cations, osmotic, electrophoretic, and structural changes play an important role for the water exchange and volume change of PPy(DBS)

Automated depression detection in text data: leveraging lexical features, phonesthemes embedding, and roberta transformer model

Indexed keywords SciVal Topics Metrics Funding details Abstract Depression is a prevalent mental disorder characterized by persistent sadness, lack of interest, and diminished pleasure. Detecting depression is crucial for timely intervention and support. In this paper, we address the task of depression detection in text data, focusing on binary classification and regression. We present our approach, leveraging a dataset comprising labeled messages from Telegram groups related to mental disorders. We begin by exploring the existing literature on depression detection, highlighting the challenges faced and the methods employed. Our approach involves data pre-processing, lexical feature extraction, phonesthemes embedding, and using the RoBERTa transformer model. We achieved promising results in the training phase through rigorous experimentation and model refinement. However, we encountered challenges upon evaluating our approach in the MentalRiskEs evaluation. We identified areas for improvement, particularly in latency and speed of detection for real-time monitoring of depression-related risks. This research contributes to the ongoing efforts in automating depression detection and provides insights into the potential of text analysis techniques for mental health assessment. We remain committed to further enhancing our methodology and advancing the field to improve the well-being of individuals affected by depression.Universidad Tecnológica de Bolíva

Pleistocene fossil turtles (Testudinoidea, cryptodira) from the Talara Tar seeps, Peru

A description of Pleistocene fossil turtles discovered in the Talara Tar Seeps, Tablazos deposits of the northern coast of Peru is provided in this paper. The specimens are mostly fragmentary plates of carapaces and plastra of turtles belonging to two cryptodiran families of the superfamily Testudinoidea, identified to genus level based on measurements and comparisons with extant and fossil taxa and identification of mosaic diagnostic features. Turtles of the Geoemydidae family are the most abundant, with fossil remains attributed to Rhinoclemmys (indeterminate species). Less abundant fossil remains belong to the Testudinidae, with specimens attributed to the genus Chelonoidis (indeterminate species). These fossils show that the northern coast of Peru had ecosystems that supported abundant aquatic and terrestrial turtles (tortoises) during the Pleistocene in areas where they are completely absent today. © 2019 Facultad de Ciencias Biologicas, Universidad Nacional Mayor de San Marcos. All rights reserved