Catalyzing sustainable development: insights from the international workshop on STI policies and innovation systems in Central America.

This article examines the landscape of Science, Technology, and Innovation policies in Central America, focusing on Nicaragua, Guatemala, Honduras, and El Salvador. These nations face significant challenges in leveraging STI for sustainable development, including financial constraints and limited resources. Additionally, Central America struggles with systemic issues such as corruption, violence, and high levels of emigration, further complicating efforts to advance STI.

gen. nov., sp. nov.: a new water strider from the Colombian Pacific region (Insecta, Hemiptera, Gerridae).

A new genus of Gerridae (Insecta, Hemiptera, Heteroptera) in the subfamily Trepobatinae, , with a single included species, . , is described from the Colombian Pacific region. Representatives of the new genus were collected in mangrove lagoons of Buenaventura Bay, Valle del Cauca Department.

Description of a new species and new records of Gerromorpha (Insecta: Hemiptera: Heteroptera) from Panama and Colombia.

The fauna of semiaquatic bugs (Insecta: Hemiptera: Heteroptera: Gerromorpha) from Panama has been explored mainly between the end of the 19th century and the first half of the 20th century, with few reports since then, whereas that from Colombia has been intensively studied in the last decade. Here, we describe Rhagovelia joceliae Rodrigues Moreira, sp. nov.

Description of two new species of Neoplea Esaki amp; China (Hemiptera: Pleidae) from Colombia.

Neoplea hyaloderma n. sp. and N.

Balancing biofunctional and biomechanical properties using porous titanium reinforced by carbon nanotubes.

Despite the well-known advantages of the titanium-based implant systems, they still lack an optimal balance between biofunctionality and mechanical strength, especially regarding the modulation of cellular response and a desired implant osseointegration. In this work, we fabricated a nanocomposite based on porous commercially pure grade 4 titanium (c.p.

The role of OH…O and CH…O hydrogen bonds and H…H interactions in ethanol/methanol-water heterohexamers.

Bioethanol is one of the world's most extensively produced biofuels. However, it is difficult to purify due to the formation of the ethanol-water azeotrope. Knowledge of the azeotrope structure at the molecular level can help to improve existing purification methods.

Theoretical design of stable small aluminium-magnesium binary clusters.

We explore in detail the potential energy surfaces of the Al(x)Mg(y) (x, y = 1-4) systems as case studies to test the utility and limitations of simple rules based on electron counts and the phenomenological shell model (PSM) for bimetallic clusters. We find that it is feasible to design stable structures that are members of this set of small Al-Mg binary clusters, using simple electron count rules, including the classical 4n + 2 Hückel model, and the most recently proposed PSM. The thermodynamic stability of the title compounds has been evaluated using several different descriptors, including the fragmentation energies and the electronic structure of the systems.

Intershell spacing changes in MWCNT induced by metal-CNT interactions.

The intershell spacing in different regions of a multi-walled carbon nanotube (MWCNT) was determined by analysis of high resolution transmission electron (HR-TEM) micrographs. Three general effects can be pointed out, (1) the regular intershell spacing of a CNT is bigger than that in a graphitic carbon because the curvature generates geometrical and electronic deformations which increase repulsion forces between the graphene sheets, (2) when an extra curvature appears, e.g.

Topological analysis of tetraphosphorus oxides (P4O 6+n (n = 0-4)).

Quantum chemical calculations were used to analyze the chemical bonding and the reactivity of phosphorus oxides (P4O6+n (n = 0-4)). The chemical bonding was studied using topological analysis such as atoms in molecules (AIM), electron localization function (ELF), and the reactivity using the Fukui function. A classification of the P-O bonds formed in all structures was done according to the coordination number in each P and O atoms.

An orbital and electron density analysis of weak interactions in ethanol-water, methanol-water, ethanol and methanol small clusters.

A computational study of (ethanol)(n)-water, n = 1 to 5 heteroclusters was carried out employing the B3LYP∕6-31+G(d) approach. The molecular (MO) and atomic (AO) orbital analysis and the topological study of the electron density provided results that were successfully correlated. Results were compared with those obtained for (ethanol)(n), (methanol)(n), n = 1 to 6 clusters and (methanol)(n)-water, n = 1 to 5 heteroclusters.

The dynamic behavior of a liquid ethanol-water mixture: a perspective from quantum chemical topology.

Quantum Chemical Topology (QCT) is used to reveal the dynamics of atom-atom interactions in a liquid. A molecular dynamics simulation was carried out on an ethanol-water liquid mixture at its azeotropic concentration (X(ethanol)=0.899), using high-rank multipolar electrostatics.

Average structural analysis of tar obtained from pyrolysis of wood.

Conventional analytical methods such as (1)H NMR, vapor pressure osmometry (VPO) and elemental analysis were used to characterize the tar obtained from pyrolysis of pine. The major fraction of tar obtained during pyrolysis of pine at different temperatures was the insoluble fraction in n-heptane which corresponds to asphaltenes; this fraction was characterized and analyzed using average structural parameters. The structural unit of the tar is composed of one aromatic ring substituted by aliphatic chains, olefinic groups and the presence of oxygenated groups.

Heterogeneous CO(2) evolution from oxidation of aromatic carbon-based materials.

Carbon dioxide is one of the main gaseous products in oxidation of carbonaceous materials via both homogeneous and heterogeneous reactions. However, the mechanisms of heterogeneous CO(2) evolution during oxidation of aromatic carbon-based materials are not known in detail. Using density functional theory, a new oxidation mechanism of aromatic hydrocarbons with atomic oxygen was suggested to consist of four main steps, namely, (1) adsorption of oxygen atom, (2) insertion of O atom into the ring, (3) rearrangement to form a five-membered ring and four-membered ring lactone group, and (4) desorption of CO(2).

A linear energy relationship between activation energy and absolute hardness: a case study with the O(3P) atom-addition reactions to polyaromatic hydrocarbons.

A new linear relationship between absolute hardness and global activation energy of O-addition reaction to a series of aromatic hydrocarbons (benzene, naphthalene, phenanthrene, and pyrene) is presented. A total of seventeen O((3)P)-addition reactions were evaluated. Thermal rate constants were calculated for each elementary reaction and used to estimate the total rate constants.

Low-temperature catalytic adsorption of NO on activated carbon materials.

The catalytic adsorption of NO on activated carbon materials provides an appropriated alternative for the control of low-concentration emissions of this air pollutant. The surface complexes formed upon NO adsorption at 30 degrees C were studied by X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD). The effects of the addition of O2 and the presence of copper as a catalyst were studied.

Molecular interaction of (ethanol)2-water heterotrimers.

The potential energy surface of the (ethanol)2-water heterotrimers for the trans and gauche conformers of ethanol was studied using density functional theory. The same approximation was used for characterizing representative clusters of (ethanol)3, (methanol)3, and (methanol)2-water. Trimerization energies and enthalpies as well as the analysis of geometric parameters suggest that the structures with a cyclic pattern in the three hydrogen bonds of the type O-H---O (primary hydrogen bonds), where all molecules are proton donor-acceptor at the same time, are more stable than those with just two primary hydrogen bonds.

Effect of Ni and Pd on the geometry, electronic properties, and active sites of copper clusters.

The geometry, electronic properties, and active sites of copper clusters doped with Ni or Pd atoms, Cu(n)()(-)(1)M (n = 2-6; M = Ni, Pd) have been investigated using first-principles methods. Planar structures are energetically favorable in Cu(n)()(-)(1)Ni (n = 2-6). However, for Pd-doped clusters, three-dimensional structures are competitive in energy, and for n = 6, the most stable structure is not planar.

Theoretical study of the interaction of molecular oxygen with copper clusters.

A new method based on frontier orbital theory has been used to investigate the binding site of molecular oxygen to neutral and anion copper clusters. It has been shown that one can make useful predictions of the binding sites based on the knowledge of the donor local reactivity of the cluster using the condensed Fukui function, f(-)(Ff). In this way, it was found that Cu(3), Cu(5), and Cu(5)(-) have the highest reactivity toward molecular oxygen.

Fixed subaortic stenosis: the value of cross-sectional echocardiography in evaluating different anatomical patterns.

We present a study using cross-sectional echocardiography in 39 patients (29 male and 10 female) with discrete subaortic stenosis. Five parameters were evaluated in the study: the morphology of the obstruction, the distance of the stenosis from the aortic valve, the type of insertion, the base of implantation, and any associated anomalies. The lesion could be divided into groups with either fibrous or fibromuscular shelves.

[Scimitar syndrome in the newborn child and infant].

We present 10 symptomatic patients with scimitar syndrome. Their age was below 1 year and four were newborn babies. In 5 patients there was secundum atrial septal defect and in one there was a patent ductus arteriosus.

[Double orifice mitral valve. Study with two-dimensional echocardiography].

Double orifice mitral valve is a rare congenital anomaly which is frequently associated with atrioventricular defects. According to its structure it is classified as central, commissural or valvar. Diagnosis by cross-sectional echocardiography was verified in 4 patients with a double orifice mitral valve of the central type.

Cricopharyngeal dysphagia and gastro-oesophageal reflux.

Nasal regurgitation of milk and choking after feeding were observed in a 1,450 g newborn boy. A nasogastric tube was inserted and several episodes of aspiration pneumonia occurred after every interruption of gavage. Weight gain was very slow.

[Infantile myoclonic encephalopathy with opsoclonus and neuroblastoma. Apropos of 2 cases].

Two cases of infantile myoclonic encephalopathy with opsoclonus and neuroblastoma are reported. One of them was observed in a 16-month-old boy and the remaining one in a 13-month-old girl. In both cases the tumour was a stade III abdominal neuroblastoma.