Publications by authors named "Francisco Ballesteros"

In this study, we conduct a comparative analysis of two density matrix construction methods: the generalized many-body expansion for building density matrices (GMBE-DM) based on the set-theoretical principle of inclusion/exclusion and the adjustable density matrix assembler (ADMA) based on the Mulliken-Mezey ansatz. We apply these methods to various noncovalent clusters, including water clusters, ion-water clusters, and ion-pair clusters, using both small 6-31G(d) and large def2-TZVPPD basis sets. Our findings reveal that the GMBE-DM method, particularly when combined with the purification scheme and truncation at the one-body level [GMBE(1)-DM-P], exhibits superior performance across all test systems and basis sets.

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With relevant chemical space growing larger and larger by the day, the ability to extend computational tractability over that larger space is of paramount importance in virtually all fields of science. The solution we aim to provide here for this issue is in the form of the generalized many-body expansion for building density matrices (GMBE-DM) based on the set-theoretical derivation with overlapping fragments, through which the energy can be obtained by a single Fock build. In combination with the purification scheme and the truncation at the one-body level, the DM-based GMBE(1)-DM-P approach shows both highly accurate absolute and relative energies for medium-to-large size water clusters with about an order of magnitude better than the corresponding energy-based GMBE(1) scheme.

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In this work, we report the benchmark binding energies of the seven complexes within the L7 data set, six host-guest complexes from the S12L data set, a C dimer, the DNA-ellipticine intercalation complex, and the largest system of the study, the HIV-indinavir system, which contained 343 atoms or 139 heavy atoms. The high-quality values reported were obtained via a focal point method that relies on the canonical form of second-order Møller-Plesset theory and the domain-based local pair natural orbital scheme for the coupled cluster with single double and perturbative triple excitations [DLPNO-CCSD(T)] extrapolated to the complete basis set (CBS) limit. The results in this work not only corroborate but also improve upon some previous benchmark values for large noncovalent complexes albeit at a relatively steep cost.

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The balance between cost-effective and sufficiently accurate methods represents the proverbial "promised land" for quantum chemistry calculations. The burden thus falls upon theoretical and computational chemists to provide such alternatives to mitigate the issues that arise from the employ of finite computing resources. In this paper, we attempt to demonstrate the importance of the quality of the initial guess for the self-consistent field (SCF) calculation when considering cost reduction techniques.

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In this work, benchmark binding energies for dispersion-bound complexes in the L7 dataset, the DNA-ellipticine intercalation complex, and the buckycatcher-C complex with 120 heavy atoms using a focal-point method based on the canonical form of second-order Møller-Plesset theory (MP2) and the domain based local pair natural orbital scheme for the coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] extrapolated to the complete basis set (CBS) limit are reported. This work allows for increased confidence given the agreement with respect to values recently obtained using the local natural orbital CCSD(T) for L7 and the canonical CCSD(T)/CBS result for the coronene dimer (C2C2PD). Therefore, these results can be considered pushing the CCSD(T)/CBS binding benchmark to the hundred-atom scale.

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The original version of this article, unfortunately, contained an error. The first and family name of Loreto Massardo was interchanged and is now presented correctly in this article.

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Objectives: To identify baseline predictors of remission and low disease activity (LDA) in early rheumatoid arthritis (RA) from the GLADAR (Grupo Latino Americano De estudio de la Artritis Reumatoide) cohort.

Methods: Patients with 1- and 2-year follow-up visits were included. Remission and LDA were defined by DAS28-ESR (< 2.

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Objective: To define whether Amerindian genetic ancestry correlates with clinical and therapeutic variables in admixed individuals with rheumatoid arthritis (RA) from Latin America.

Methods: Patients with RA (n = 1347) and healthy controls (n = 1012) from Argentina, Mexico, Chile, and Peru were included. Samples were genotyped for the Immunochip v1 using the Illumina platform.

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Objective: The objective of this consensus is to update the recommendations for the treatment of hand, hip, and knee osteoarthritis (OA) by agreeing on key propositions relating to the management of hand, hip, and knee OA, by identifying and critically appraising research evidence for the effectiveness of the treatments and by generating recommendations based on a combination of the available evidence and expert opinion of 18 countries of America.

Methods: Recommendations were developed by a group of 48 specialists of rheumatologists, members of other medical disciplines (orthopedics and physiatrists), and three patients, one for each location of OA. A systematic review of existing articles, meta-analyses, and guidelines for the management of hand, hip, and knee OA published between 2008 and January 2014 was undertaken.

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People with anxiety disorders demand psychological attention most often. Therefore, it seems important to identify both the characteristics of the patients who demand help and the clinical variables related to that demand and its treatment. A cohort of 292 patients who requested help at a university clinical facility was studied.

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Background: Latin America is a heterogeneous region made up of different populations, cultures, latitudes, altitudes, and immigrants from different areas and ethnic groups.

Objective: The purpose of this study is to describe the clinical and demographic profile of patients with osteoarthritis (OA) evaluated by a selected group of rheumatologists in 13 Latin American countries.

Methods: A descriptive, observational, cross-sectional study was conducted in 13 Latin American countries of patients with symptomatic OA.

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The aim of this work is to study the sociodemographic and clinical characteristics of patients diagnosed with Panic Disorder with Agoraphobia (PD/Ag), as well as the characteristics of the treatment and its results and cost in a University Psychology Clinic. Fifty patients demanded psychological assistance for PD/Ag; 80% were women, with an average age of 29.22 years (SD = 9.

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Objective: To identify susceptibility loci for rheumatoid arthritis (RA) in Latin American individuals with admixed European and Amerindian genetic ancestry.

Methods: Genotyping was performed in 1,475 patients with RA and 1,213 control subjects, using a customized BeadArray containing 196,524 markers covering loci previously associated with various autoimmune diseases. Principal components analysis (EigenSoft package) and Structure software were used to identify outliers and define the population substructure.

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Background: Treatment of rheumatoid arthritis (RA) has evolved dramatically in the last decade. However, little is known about the way rheumatologists in Latin America treat their patients in clinical practice, outside the scope of clinical trials.

Objective: The objective of this study was to describe treatment patterns at disease onset in early RA with data from a large, multicenter, multinational inception cohort of Latin American patients.

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In this paper we present our experience designing and developing two different systems to enable personal pervasive computing environments, Plan B and the Octopus. These systems were fully implemented and have been used on a daily basis for years. Both are based on synthetic (virtual) file system interfaces and provide mechanisms to adapt to changes in the context and reconfigure the system to support pervasive applications.

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We report a patient with a nasal hemangiopericytoma associated with an oncogenic hypophosphatemic osteomalacia (OHO). This syndrome results from tumor products that decrease renal tubular phosphate resorption, leading to the osteomalacia. This patient presented with classic bone manifestations of osteomalacia and a nasal tumor.

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