Cultura

This research analyzes the feasibility of using chocolate clam shells (Megapitaria squalida) as a mineral additive in concrete mixtures to reduce the environmental impact of marine waste and the high consumption of Portland cement. A quantitative methodological approach was applied, including the collection, cleaning, crushing, calcination, and grinding of the biomaterial, followed by compressive strength and durability tests on concrete specimens with 10% partial cement replacement. The results showed that shells calcined at 800°C and 1000°C exhibit suitable pozzolanic properties and improve the mechanical strength of concrete, exceeding the values obtained in reference mixtures. Likewise, electrical resistivity tests indicated a very low chloride penetration, demonstrating high durability and good protection against steel reinforcement corrosion. The findings confirm that Megapitaria squalida shells, due to their high calcium carbonate (CaCO₃) content, represent a sustainable and economically viable alternative for producing eco-friendly concrete. Their incorporation contributes to reducing CO₂ emissions associated with cement manufacturing, promoting practices aligned with the Sustainable Development Goals (SDGs).

This article analyzes the real estate boom in Mazatlán, Sinaloa, highlighting the key factors that have driven the city’s recent urban and tourism development. The study examines the impact of national and foreign investment, infrastructure improvements, and public policies that have encouraged market expansion. It also explores the most effective marketing strategies used by real estate companies, emphasizing digital transformation, brand building, and personalized customer experiences. The findings suggest that competitiveness in Mazatlán’s real estate market largely depends on technological innovation, professional service standards, and adaptation to emerging consumer trends. Mazatlán is projected to remain one of the most promising real estate investment destinations on Mexico’s Pacific coast.

Introducción: El avance de la inteligencia artificial generativa (IAG) y de los grandes modelos de lenguaje (LLM) ofrece nuevas oportunidades para personalizar la enseñanza y optimizar los procesos de evaluación, aunque también plantea desafíos éticos y pedagógicos para las instituciones educativas. Objetivo: Analizar el uso de ChatGPT-4 en la adaptación personalizada de materiales de aprendizaje, la evaluación de respuestas abiertas y la generación de retroalimentación para estudiantes en contextos escolares y universitarios. Metodología: Se desarrolló un estudio con enfoque mixto. En la fase de adaptación de materiales participaron 110 estudiantes de dos escuelas superiores de Montevideo, Uruguay (40.9% mujeres). En la fase de evaluación y retroalimentación se analizaron 54 respuestas abiertas elaboradas por estudiantes de una maestría en una universidad finlandesa. ChatGPT-4 evaluó las respuestas mediante cinco criterios (relevancia contextual, precisión factual, completitud, consistencia lógica y ortografía y gramática), asignó calificaciones y generó retroalimentación personalizada. Se aplicaron análisis cuantitativos y cualitativos, incluyendo el índice de Levenshtein y comparaciones de longitud textual. Resultados: La adaptación personalizada de materiales contribuyó a una experiencia de aprendizaje más positiva, ajustada al nivel de los participantes; el 66.4% de los estudiantes reportó disfrutar significativamente de los materiales generados por la IAG. Asimismo, ChatGPT-4 proporcionó evaluaciones y retroalimentaciones individualizadas que favorecieron la motivación estudiantil y apoyaron la eficiencia de los procesos educativos. Conclusiones: La IAG constituye una herramienta prometedora para apoyar la personalización del aprendizaje y la evaluación educativa. Sin embargo, debe utilizarse como complemento del juicio humano, acompañada de formación específica y lineamientos éticos que garanticen un uso crítico y pedagógicamente significativo.

The present research is aimed at exploring formulations of concrete mixes that incorporate metakaolin (MK), derived from kaolin calcined at different temperatures (700°C and 800°C). The metakaolin was generated in a laboratory setting from pure kaolin extracted in the Magistral de Copala development area, Concordia, Sinaloa. The experimental design encompasses five variants of concrete mixes, including a reference standard and options with 15% and 20% cement replacement with metakaolin at 700°C, as well as mixes with the same substitution percentage using metakaolin at 800°C. The collected results indicate that fluctuations in the calcination temperature do not exert a substantial impact on the mechanical and deterioration resistance characteristics of concrete, as both temperatures promote the formation of metakaolins with high pozzolanic activity. The formulation highlighted for its superior performance in terms of mechanical strength (compression) and durability (microstructural parameters, electrical resistivity, chloride migration) is the one using MK calcined at 800°C, replacing 15% of the weight of the cement. These findings underscore the possibility of obtaining environmentally friendly mineral additions by substituting significant amounts of cement, thus contributing to reducing the carbon footprint associated with its manufacturing.

Nitocra duyxuyenensis sp. nov. Figs 1, 2, 3, 4, 5, 6, 7, 8, 9 Type material. • Adult female holotype dissected and mounted on one slide (ZC-DTU -COPEPODA-0014) • adult male allotype dissected and mounted on one slide (ZC-DTUCOPEPODA-0015) • two female and two male paratypes preserved in 70 % ethanol (ZC-DTU -COPEPODA-0013). Type locality. Hyporheic zone in Vu Gia–Thu Bon river (15°50'15"N, 108°09'05"E), Quang Nam province, Central Vietnam. Differential diagnosis. Caudal rami 1.2 × as long as wide. Anal operculum with six marginal spinules. Female antennule eight-segmented; male antennule haplocer, eight-segmented. Antenna with allobasis. P 1 Exp - 2 with inner seta; Exp - 3 with five elements in all; P 1 Enp - 1 reaching approximately the middle of Exp - 2, with inner seta; Enp - 2 with three elements. P 2 – P 4 Exp - 2 with inner seta, Exp - 3 with seven setae / spines; P 2 – P 4 Enp - 1 without, Enp - 2 with inner seta, Enp - 3 with four, five, and five setae / spines respectively. Female P 5 Exp with six, Benp with five setae and reaching the middle of Exp; male P 5 Exp with six, baseoendopods fused medially, each with three setae. Description of the adult female. Habitus (Fig. 1 A) semicylindrical; total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 492 to 546 μm (average = 519 μm, n = 5; holotype = 546 μm). Nauplius eye not visible. Rostrum (Fig. 1 A) linguiform, small, not reaching end of first antennule segment, with pair of tiny sensilla subapically. Prosome four-segmented, comprising cephalothorax with completely fused first pedigerous somite, and three free pedigerous somites; cephalothorax and P 2 – P 4 - without surface ornamentation other than sensilla as shown (Fig. 1 A). Urosome five-segmented, comprising fifth pedigerous somite, genital double-somite, two free urosomites, and anal somite with caudal rami (Fig. 1 A, B); P 5 - bearing somite without spinular ornamentation, with few posterior sensilla; genital double-somite (Fig. 1 A – C) formed by the fusion of genital and third urosomite, with dorsolateral suture indicating original division, completely fused ventrally, proximal half with dorsolateral sensilla close to suture and with short row of lateral spinules as depicted (Fig. 1 B), ventrally with medially interrupted row of minute spinules and with sensilla along partial ventral suture, genital field close to anterior margin of first half of somite (Figs 1 C, 6 B), with large median copulatory pore; fourth urosomite with posterior spinular row ventrally (Fig. 1 C); fifth urosomite with medial ventrolateral row of small spinules and with continuous row of small ornaments close to posterior margin, without sensilla (Fig. 2 A, B); anal somite (Figs 1 A, 2 A, B) with median ventrolateral row of spinules, with strong spinules close to caudal rami dorsally (Figs 1 A, 2 A), and with comparatively smaller ornaments ventrally (Fig. 2 B), anal operculum semicircular with six strong marginal spinules and flanked by pair of sensilla (Figs 1 A, B, 2 A). Caudal rami (Figs 1 B, C, 2 A, B) short, subquadrate, 1.2 × as long as wide, with seven elements each; anterolateral seta I slender, short, ~ 0.3 × as long as caudal ramus; anterolateral seta II and posterolateral seta III smooth, the former slightly shorter than the latter, with short strong spinules at base of seta II; outer apical seta IV and middle apical seta V well-developed, with fracture planes, seta V longest; distal inner accessory seta VI slender, smooth, 0.9 as long as caudal ramus, with several small spinules at its base; dorsal seta VII tri-articulated, ~ 2.4 × as long as caudal ramus, issuing close to posterior margin of ramus. Antennule (Fig. 3 A) 8 - segmented, long and slender; all segments smooth except for first segment with a row of spinules; all setae smooth except for pinnate seta on first segment. Aesthetasc on fourth segment, fused to long seta, reaching well beyond distal end of last segment. Armature formula as follows: 1 (1), 2 (7), 3 (2), 4 (2 + (1 + ae)), 5 (2), 6 (1), 7 (4), 8 (5 + acrothek). Antenna (Fig. 3 B) relatively short, composed of coxa, allobasis, one-segmented endopod, and one-segmented exopod. Coxa short, unornamented. Allobasis 2.7 × as long as wide, with a short row of inner spinules proximally, and several minute proximal spinules close to coxa. Exopod with three distal unequal setae (one bare, two unipinnate). Endopod with inner longitudinal spinular row; lateral armature consisting of one inner spine and one strong inner seta; distally with one smooth seta, four geniculate setae and one distal outer geniculate seta fused basally to slender element. Mandible (Fig. 3 C) with well-developed coxa; gnathobase with ~ 11 teeth as shown, and single lateral seta. Mandibular palp 2 - segmented, first segment (basis) with one strong plumose seta; endopod with one lateral and four smooth apical setae. Maxillule (Fig. 3 D) with well-developed praecoxa; arthrite with two surface setae, and four large robust distal spines. Coxal endite with two smooth setae. Basis with five normal unequal setae distally. Endopod 1 - segmented, with four slender smooth setae. Maxilla (Fig. 3 E) without spinular ornamentation on syncoxa, the latter with two endites; proximal endite somewhat bulbous, with one strong plumose seta; distal endite cylindrical, with three subequal setae. Allobasis drawn out into long claw accompanied by a shorter bare seta. Endopod short, one-segmented; with two subequal, smooth setae. Maxilliped (Fig. 3 F) with short and stout syncoxa, the latter 1.3 × as long as wide, with short row of posterior spinules, with one small bare seta subapically. Basis ~ 2.2 × as long as wide, with short row of inner spinules and with one outer subdistal spinule. Endopod drawn out into long curved smooth claw accompanied by single short slender seta. P 1 – P 4 (Figs 4 A, B, 5 A, B) with short unornamented intercoxal sclerites, the latter with dorsal tines as shown. Coxa of P 1 and P 2 with, of P 3 and P 4 without outer subdistal spinules. Basis of P 1 with spinules at the base of inner and outer spine, with additional ornaments between rami; basis of P 2 – P 4 with spinules at the base of outer spiniform (P 2) and setiform elements (P 3 – P 4), of P 2 and P 3 with, of P 4 seemingly without spinules close to the base of the endopod. Rami three-segmented. Exopodal segments with outer and subdistal spinules as shown; Exp - 1 with outer spine, without inner armature; Exp - 2 with outer spine and inner seta; Exp - 3 with three outer spines, two distal geniculate setae and without inner armature (P 1) or with one distal outer spiniform and one distal inner setiform element and with two inner setae (P 2 – P 4). Endopodal segments with outer ornaments as figured; P 1 Enp visibly longer than Exp, Enp - 1 not reaching beyond Exp - 2; Enp - 1–2 with inner seta, Enp - 3 with three elements; P 2 – P 4 Enp shorter than Exp; P 2 – P 3 Enp reaching distal tip of Exp - 2, P 4 Enp reaching slightly above the middle of Exp - 2; Enp - 1 short, wider than long, unarmed; Enp - 2 with one inner seta and a projection at the inner distal corner; Enp - 3 with one (P 2) or two (P 3 and P 4) inner setae, two distal elements, and one outer spine; length ratio of armature elements on P 3 Enp - 3 (starting from outer most apical spine) 1: 1.9: 4.7: 5.2: 2.9. Armature formula of P 1 – P 4 as in Table 1. P 5 (Fig. 6 A) with exopod and baseoendopod separated. Baseoendopod with outer unipinnate seta; endopodal lobe well-developed, with longitudinal row of outer spinules, with three inner spinulose spines, and two robust distal setae of which distal inner longest. Exopod oval, 1.6 × as long as wide, with six unequal smooth setae of which two outer and outer subdistal seta shortest. P 6 (Fig. 6 B) represented by narrow plate with one single plumose seta on each side. Description of the adult male. Body shape and general appearance as in female (Fig. 7 A); total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 476 to 508 μm (average = 492 μm, n = 2; holotype = 508 μm). Rostrum, prosomites, anal operculum, and caudal rami as in female (Fig. 7 A, C, D). Sexual dimorphism expressed in urosomal segmentation (genital and third urosomite not fused), spinular ornamentation of urosomites, antennule, basis of P 1, P 5, and P 6. Genital somite (Fig. 7 A, B) with continuous posterior dorsolateral spinular row; third urosomite with dorsolateral spinular row interrupted ventrolaterally; fourth and fifth urosomites (Fig. 1 A – D) with continuous posterior and median spinular row, respectively, and fifth urosomite with short spinular row ventrally. Antennule (Fig. 8 A) haplocer, 8 - segmented, with geniculation between sixth and seventh segments; all segments smooth except for first segment with some spinules. All setae smooth except for plumose seta on first segment. Fourth segment with large aesthetasc fused to long seta overreaching last segment, and with one robust short unipinnate spine. Armature formula as follows: 1 (1), 2 (8), 3 (5), 4 (6 + (1 + ae)), 5 (0), 6 (1), 7 (1), 8 (7 + acrothek). Antenna, mandible, maxillule, maxilla, and maxilliped (not shown) as in female. P 1 (Fig. 9 A) as in female except for inner spine of basis modified into element with rounded tip; inner margin of Exp - 2 and outer margin of Enp - 2 naked. P 2 and P 4 (not shown) as in female. P 3 (Fig. 9 B) as in female except for absence of spinular row on distal margin of basis, and for length ratio of all setae on Enp - 3 (1: 1.3: 1.5: 3.6: 1.2). P 5 baseoendopods (Fig. 8 B) fused medially. Baseoendopod with one outer long smooth seta, endopodal lobe weak, with three naked spiniform setae of which outermost shortest, innermost longest. Exopod with six smooth unequal setae; relative length of exopodal setae (from outermost to innermost seta) 1: 0.5: 1.2: 1.3: 0.7: 1.8. P 6 (Fig. 8 C) small, with two bare unequal setae, of