ABSTRACT: Cowpea is a food crop representing an important source of proteins and income, mainly for people living in the north and northeast of Brazil. This study aimed to evaluate the growth performance of two cowpea cultivars under four different ionic concentrations of the growth solution. Thus, a pot experiment was performed using the sand culture technique and set up in a completely randomized design with a 2 x 4 factorial scheme, using four replications and one plant per plot. After the period of growth, the parameters such as length of the shoot, stem diameter, number of leaves, number of secondary branches, number of pods, fresh weight of the stem, stem dry mass, leaf dry mass, shoot dry mass, and root/shoot ratio were obtained. The results pointed out that there was a significant interaction effect on parameters like stem diameter, leaf dry mass, shoot dry mass, and number of leaves. Both cultivars were strongly responsive to changes in ionic concentration, indicating a greater biomass production at ionic concentrations of 90% and 120%. A greater growth performance for BRS Rouxinol than BRS Itaim was observed, while the second cultivar indicated a high tolerance as exposed to the highest ionic concentrations.

RESUMO: O feijão-caupi é um alimento que representa uma importante fonte de proteínas, e também de renda, sobretudo para os produtores rurais do Norte e Nordeste do Brasil. O objetivo deste estudo foi avaliar o desempenho de crescimento de duas cultivares de feijão caupi sob diferentes concentrações iônicas da solução nutritiva. Para tanto, um experimento em vasos foi conduzido em delineamento inteiramento casualizado com arranjo fatorial 2 x 4, utilizando quatro repetições e um planta por parcela. Após o período de crescimento, os parâmetros tais como: comprimento do ramo principal, diâmetro do caule, número de folhas, número de ramos secundários, número de vagens, peso fresco do caule, peso seco do caule, peso seco das folhas, peso seco da parte aérea e a relação raiz parte aérea foram obtidas. Os resultados apontaram que houve interação significativa dos fatores sobre o diâmetro do caule, peso seco das folhas, peso seco da parte aérea e o número de folhas. Ambas as cultivares foram responsivas a mudança na concentração iônica da soução, revelando maior rendimento de biomassa nas concentrações de 90% e 120%. Uma maior performance de crescimento foi constatada para BRS Rouxinol comparado a BRS Itaim, enquanto a segunda cultivar mostrou elevada tolerância às altas concentrações iônicas na solução.

ABSTRACT This article presents the issue of water access in the context of the Paraguayan Chaco and the alternative that the Non-Governmental Organization (NGO), Pro Comunidades Indígenas (PCI), along with indigenous and peasant communities in the area, has been experimenting with to address the problem; from water access to the challenge of its treatment and purification for human consumption. The methodological approach of this research is qualitative, employing participant observation and semi-structured interviews with technicians, coordinators of the implementing institution of the nature-based safe water system, and community leaders. Additionally, bibliographic consultations and review of PCI institutional documents were conducted to obtain secondary data. The results of this study provide a description of PCI's experiences and lessons learned about a nature-based safe water treatment system, which utilizes biofilters such as stone, gravel, sand, and charcoal. This article covers the trials for the construction of the sys- tem, explains its operation, and discusses its implementation in communities. The nature-based safe water system proves effective for small populations and provides a solution to a long-standing problem in the Chaco territory. Its construction is easy, short-term, and much less costly than conventional water treatment systems. Additionally, the joint construction of the system with the residents, technical training in its operation and maintenance, greatly contributes to its sustainability. This article contributes to the identification, application, and study of suitable water systems for areas with difficult access to this vital liquid, such as the Paraguayan Chaco. Furthermore, it is an innovative and eco-friendly system, meaning it is environmentally friendly.

RESUMEN Este artículo presenta la problemática del acceso al agua en el contexto del Chaco paraguayo y la alternativa que la Organización No Gubernamental (ONG), Pro Comunidades Indígenas (PCI), junto con las comunidades indígenas y campesinas de la zona, ha venido ensayando para buscar solución a la problemática; desde el acceso al agua hasta el desafío de su tratamiento y potabilización para el consumo humano. El enfoque metodológico de esta investigación es cualitativo, empleando la observación-participante y entrevistas semiestructuradas con técnicos, coordinadores de la institución ejecutora del sistema de agua segura basado en la naturaleza y líderes comunitarios. Además, se realizaron consultas bibliográficas y revisión de documentos institucionales de PCI para obtener datos secundarios. Los resultados de este estudio arrojan la descripción de las experiencias y las lecciones aprendidas de PCI sobre un sistema de tratamiento de agua segura basado en la naturaleza, que utiliza los llamados biofiltros, como piedra, grava, arena y carbón. Este artículo parte de los ensayos para la construcción del sistema, la explicación del funcionamiento de este hasta su implementación en las comunidades. El sistema de agua segura basado en la naturaleza resulta efectivo para poblaciones pequeñas y proporciona una solución a una problemática de larga data en el territorio chaqueño. Su construcción es fácil, de corto plazo y mucho menos costoso que el sistema convencional de tratamiento de agua. Así también, la construcción conjunta del sistema con los pobladores, la capacitación técnica a los mismos en su operación y mantenimiento, contribuyen enormemente a la sostenibilidad de este. Este artículo es una contribución a la identificación, aplicación y estudio de sistemas de agua adecuados para zonas de difícil acceso a este líquido vital, como es el caso del Chaco paraguayo. Además, se trata de un sistema innovador y ecológico, es decir, amigable con el medio ambiente.

Stormwater harvesting is a promising solution for global freshwater depletion, particularly in tropical regions with abundant rainfall. However, it is not widely used due to the lack of suitable treatment technologies for domestic applications. Multi-stage filtration (MSF) is an effective integrated treatment technology that provides a cost-effective alternative for stormwater treatment. This study investigated MSF's capacity for treating stormwater at different stages. The MSF designed and built comprised the down-flow roughing filter (DRF) and slow sand filter (SSF). The results achieved by the MSF for the treated effluents were: pH (7.1-8.1), temperature (27.6-29.4°C), electrical conductivity (EC) (100-190 µS/cm) and total dissolved solids (TDS) (70-130 mg/L). Turbidity removal efficiency of the MSF was in the range of 36-99% (5.825-164.05 NTU) and the overall average removal efficiency of the MSF was 74%, 90% and 86% for total coliforms (TC) (360-11 800 CFU/ 100 mL), faecal coliforms (FC) (0-1 300 CFU/100 mL) and Enterococcus spp. (120- 1 400 CFU/100 mL), respectively. The study identified stormwater reuse potentials based on international guidelines and benchmarks. For the treated effluent, pH, temperature, EC and TDS were all within the permissible limits for toilet, laundry, bathing, recreational and agricultural water reuse, while turbidity suited agricultural (non-food crop) and restricted urban reuse. 46% of the effluent was suitable for recreational purposes as this satisfied the 50 NTU standard. 62.5% of the effluent satisfied the FC standard for toilets and urinals and agricultural reuse (non-food crop) purposes, while 87.5 % of the effluent satisfied urban reuse purposes (restricted access). 66.67% of the effluent satisfied the Enterococcus spp. standard for agricultural reuse (non-food crop). All treated effluents satisfied the TC bathing standard. This study shows that after minimal disinfection, stormwater effluents offer potential reuse in household applications, thereby reducing potable water demand.

Abstract Background: Inland sand dunes are expanding and increasing mobility. Knowledge on the plants growing on them is keystone for their management. One of the largest inland dune systems in Mexico is the Médanos de Samalayuca area. Questions: How many and which species of vascular plants are in Samalayuca? Which is the distribution pattern of that flora? Are there endemisms? Are there species of conservation concern? Studied species: Vascular plants. Study site and dates: Médanos de Samalayuca protected area, northern Chihuahua, Mexico; 2017-2022. Methods: A database was generated based on literature, electronic sources, herbarium specimens, photographing, and collection and identification of materials. Distribution, endemism level and conservation status were recorded. Results: The updated checklist of vascular plants for Samalayuca includes 400 species of 246 genera and 65 families. Most species grow in Mixed desert scrub and in Sand dune vegetation. Almost a half are restricted to the Megamexico 1 region, followed by the North American element. One species is Threatened according to the Mexican Official Norm NOM-059, while two are Vulnerable and one is Almost threatened according to the IUCN. Ribes fontinale appears to be extinct. Conclusions: Considering the arid, extreme climate and the low stability of the psammophilous vegetation, the flora of Samalayuca is richer than expected. The area is home to regional and local endemics. The data and information generated here is baseline for further management programs and action planning to protect these fragile ecosystems and the adjacent communities.

Resumen Antecedentes: Las dunas de arena de interior se están expandiendo e incrementando movilidad. El conocimiento sobre sus plantas es clave para su manejo. En México, uno de los mayores sistemas de dunas de interior es el área de los Médanos de Samalayuca. Preguntas: ¿Cuántas y cuáles especies de plantas vasculares hay en Samalayuca? ¿Qué patrón de distribución presenta esa flora? ¿Hay endemismos? ¿Existen especies en estado de riesgo? Especies de estudio: Plantas vasculares. Sitio y años de estudio: Área de protección Médanos de Samalayuca, Chihuahua, México; 2017-2022. Métodos: Se generó una base de datos con base en revisión de literatura, fuentes electrónicas, especímenes de herbario, fotografías y colección e identificación de material botánico. Se registró la distribución, grado de endemismo y estado de conservación de cada especie. Resultados: La lista florística incluye 400 especies de 246 géneros y 65 familias. La mayoría crecen en Matorral desértico micrófilo y en Vegetación de dunas arenosas. Casi la mitad se restringen a la región conocida como Megamexico 1 y 32 % son Norteamericanas. Una está Amenazada de acuerdo a la Norma Oficial Mexicana NOM-059, mientras dos son Vulnerables y una Casi amenazada de acuerdo a la IUCN. Ribes fontinale parece estar extinta. Conclusiones: Considerando el clima árido y extremo y la inestabilidad de la vegetación psamófila, la flora de Samalayuca es más rica de lo esperado. El área alberga endemismos regionales y locales. La información generada puede apoyar programas de manejo y acciones para proteger estos frágiles ecosistemas.

The purpose of this article is to demonstrate how the once-off increase in regional income that will result from investment in roads and the recurring increase in regional income that will stem from the use of economically viable new roads can be estimated. Once-off economic benefits occur because of the multiplier effect triggered by the initial investment expenditure on a road, while recurring economic benefits result from the income accelerator effect that use of the road during its service period will have. To determine the regional income multiplier effect of the investment expenditure on a proposed road during its construction period, it is necessary to estimate (i) the tax amounts included in the investment amount as a ratio of the total project investment amount, (ii) the monetary amount saved by project workers as a ratio of the total project investment amount, and (iii) the expenditure on imported project inputs as a ratio of the total project investment amount. An analysis that incorporates the above-mentioned three fund leakages from the circular flow of regional income will show that the representative income multiplier of South African rural paved road construction projects has a value of 4,58. The gross national income multiplier effect stemming from road construction expenditure can be categorised as follows: In the rating scale above, a gross national income multiplier effect stemming from road construction projects with a value of less than 2,00 is regarded as "poor", because such a multiplier value is usually associated with economically unviable road projects. Gross national road construction multiplier effects with a value of 2,00 or more are associated with economically viable projects. An analysis as referred to above will show that, with a once-off gross income multiplier value of 4,58, the construction of economically viable roads will afford the government a "very good" opportunity to generate income effectively, especially considering that the national economy-wide gross income multiplier in South Africa is 3,27, which shows that the gross income multiplier of road construction is 40% higher than the economy-wide gross income multiplier. The reasons why the once-off gross regional income multiplier stemming from construction expenditure on rural road projects is "very good" are as follows: Multiplier Rating 1 – 1,99 Poor 2 – 2,99 Satisfactory 3 – 3,99 Good 4 – 4,99 Very good < 5 Excellent (1) A substantial proportion of the payroll of road construction workers is subject to zero or low personal income tax rates. (2) The propensity to consume among rural, unskilled and semi-skilled workers (in areas where rural roads are constructed) is generally high, which implies a low savings leakage. (3) Labourers needed for road construction are usually recruited from (or from close by) the areas where a road is to be built. Furthermore, low-income earners tend to buy and consume goods that are produced locally. (4) Generally, there is a relatively small need to import economic resources for road construction projects. Items like timber, sand, stone, gravel, filling material, bitumen, cement, steel and most of the road construction equipment are of regional or, at least, South African origin. The pace at which an economically viable road will stimulate regional income will be reflected by the new traffic it induces and any existing traffic that it diverts from less beneficial roads. In the social cost-benefit analysis of a road, it is estimated by what proportion induced and diverted traffic will increase the road user surplus. This expected proportional increase in road user surplus will accelerate (stimulate) the once-off regional multiplier and is termed the "regional income stimulation factor". Project-driven induced investment activities - i.e. downstream investment activities made possible by the provision of the road - usually (a) involve technically more sophisticated construction projects than the analysed road itself, (b) require the importation of a greater proportion of finished goods and specialised equipment, and (c) involve more skilled and highly skilled workers, whose income is subject to high income tax rates and who exhibit a higher propensity for saving than unskilled workers. Such downstream activities will collectively have a greater leakage effect than that incorporated in the once-off regional multiplier pertaining to construction of the road, which will depress the magnitude of the recurring regional income accelerator. The different formulae used to calculate the recurring income accelerator are detailed in the body of the article.

Hierdie artikel dui aan hoe die eenmalige verhoging in streeksinkome wat uit investeringsbesteding tydens die bou van 'n pad spruit, en die herhalende bykomende streeksinkome wat uit die gebruik van 'n ekonomies geregverdigde nuwe pad spruit, deur onderskeidelik streeksinkomevermenigvuldigerontleding en streeksinkome-versnellerontleding beraam kan word. Om die effek van die streeksinkomevermenigvuldiger van die uitgawe verbonde aan die bou van 'n pad te bepaal, moet (i) die belastings wat by die bou-uitgawe ingesluit is, as 'n verhouding van die totale bou-uitgawe, (ii) die bedrae geld wat deur projekwerkers gespaar word, as 'n verhouding van die totale bou-uitgawe, en (iii) die besteding aan ingevoerde projekinsette, as 'n verhouding van die totale bou-uitgawe, bepaal word. Ontledings wat bogenoemde drie fondslekkasies uit die kringloop van streeksinkome in ag neem, toon dat die verteenwoordigende inkomevermenigvuldiger van Suid-Afrikaanse bouprojekte vir buitestedelike geplaveide paaie 'n waarde van 4,58 het. Op die beoordelingskaal van inkomevermenigvuldigerwaardes vir die bou van buitestedelike paaie bied dit aan die staat 'n "baie goeie" geleentheid om inkome te genereer, veral as in ag geneem word dat die gemiddelde inkomevermenigvuldiger van besteding in die Suid-Afrikaanse ekonomie 'n waarde van 3,27 het. Die formules waarmee die eenmalige inkomevermenigvuldiger beraam word, word in die liggaam van die artikel uiteengesit. Die herhalende versnelde streeksinkome wat uit die gebruik van 'n ekonomies lewensvat-bare pad spruit, is gelyk aan die produk van (a) die huidige waarde van die herhalende pad-gebruikersvoordele wat uit die gebruik van die pad spruit, en (b) die waarde van die streeks-inkomeversneller van die gebruik van die pad. 'n Streeksinkomeversneller wat as verstekwaarde kan dien in die ekonomiese-impakontleding van 'n ekonomies lewensvatbare geplaveide buitestedelike pad in gevalle waar dit nie haalbaar is om 'n projek-eie versneller te probeer beraam nie, word in die artikel bereken. Die formules waarmee die herhalende-inkomeversneller beraam word, word in die liggaam van die artikel uiteengesit.

Abstract MS is extensively used in oil and gas industries, but its inherent susceptibility to corrosive attack in marine environments with high C of Cl- is a shortcoming to its applications in such inevitable medium. Coating has been a popular means of mitigating steel structures corrosion. This work assessed the effect of Zn-ZnO based AW-SS composite as AC material on a MS substrate in a marine environment. The Zn-ZnO base was separately subject to CD with SS, DLFA and LSLA particulates on MS substrates. PDP method was used to ascertain corrosion behaviors of the coated samples in a simulated SW environment. The samples ( and microstructural properties were studied by a microhardness tester and SEM, respectively. The results indicated that the samples ( increased when they were coated by SS and LSLA higher C, which had the highest and lowest (, respectively. The coatings CP improved visibly with SS, which had the highest value (61.4%), followed by DLFA (53.8%) and LSLA (44.3%). AW incorporated into Zn-ZnO is a potential AC material.

Abstract The wilt or damping-off of husk tomato is a disease caused by fungi originating in the soil, among which Fusarium oxysporum, Macrophomina phaseolina, and Rhizoctonia solani stand out, causing losses due to the lack of resistant varieties. This study aimed to determine the response of husk tomato (Physalis ixocarpa Brot.), Dalí, Siqueiros, and Tamayo hybrids, as well as cv. Gabriela, Puebla, San Miguel, and Tecozautla, to pathogenic isolates of F. oxysporum, M. phaseolina, and R. solani. The study was conducted under greenhouse conditions; sterilized substrate of river sand + peat (1:3 v/v) was placed in pots and then inoculated with three isolates of F. oxysporum 1.6x105 CFU, two of M. phaseolina, and three of R. solani (8 g of infested sorghum seed/pot, of each fungus). Five seeds of the corresponding husk tomato cultivar were deposited in each pot, then covered with the same substrate and incubated for 30 days. A completely randomized design was used, with three repetitions (pots). In the control treatment, the seeds were sown on soil without fungus. The emergence of seedlings was estimated nine days after sowing (das), and the severity of infection for each of the pathogens (scale of 0-5) at 30 das. Data were analyzed using nonparametric statistics. The seven cultivars tested were susceptible to the species F. oxysporum, M. phaseolina, and R. solani; some of the isolates tested exerted a significant differential effect of virulence on some of the varieties studied.

Resumen La marchitez o secadera del tomatillo es una enfermedad causada por hongos con origen en el suelo, entre los que destacan Fusarium oxysporum, Macrophomina phaseolina y Rhizoctonia solani, causando pérdidas por la carencia de variedades resistentes. El objetivo de este estudio fue determinar la respuesta del tomatillo (Physalis ixocarpa Brot.), híbridos Dalí, Siqueiros y Tamayo, así como los cv. Gabriela, Puebla, San Miguel y Tecozautla, hacia aislados patogénicos de F. oxysporum, M. phaseolina y R. solani. El estudio se realizó bajo condiciones de invernadero, en macetas se colocó arena de río + sustrato de turba (1:3 v/v) esterilizado y después se inoculó, con tres aislados de F. oxysporum 1.6x105 UFC, dos de M. paseolina y tres de R. solani (8 g de semilla de sorgo infestada/maceta, de cada hongo). En cada maceta se depositaron cinco semillas del cultivar de tomatillo correspondiente, luego se taparon con el mismo sustrato e incubaron por 30 días. Se utilizó un diseño completo al azar, con tres repeticiones (macetas). En el tratamiento testigo las semillas se sembraron sobre suelo sin hongo. A los nueve días después de la siembra (dds) se estimó la emergencia de plántulas, 30 dds, la severidad de la infección de por cada uno de los patógenos (escala de 0-5). Los datos se analizaron mediante estadística no paramétrica. Los siete cultivares probados fueron susceptibles a las especies F. oxysporum, M. phaseolina y R. solani, algunos de los aislados probados ejercieron un efecto significativo diferencial de virulencia, en algunas de las variedades estudiadas.

Resumo A pitaia vermelha (Hylocereus costaricensis) é uma promissora espécie, com elevado potencial de cultivo devido às qualidades organolépticas e funcionais de seus frutos. Entretanto, a salinidade da água de irrigação pode afetar o rendimento produtivo da cultura. Diante disso, materiais ricos em substâncias orgânicas podem minimizar os danos provocados pelo excesso de sais no solo e/ou na água. Assim, o objetivo deste trabalho foi avaliar a influência de fontes de matéria orgânica como atenuante do estresse salino na produção e respostas bioquímicas de mudas de pitaia vermelha. O delineamento inteiramente casualizado em esquema fatorial 4 × 5, com cinco fontes de matéria orgânica (húmus, esterco ovino, biofertilizante, composto orgânico e areia + solo) e quatro salinidade (0.6, 2.6, 4.6 e 6.6 dS m-1), com quatro repetições e duas plantas por vaso foi utilizado. O comprimento da parte aérea, comprimento da raiz, diâmetro do cladódio, número de cladódios, número de brotos, volume da raiz, massa seca da parte aérea, massa seca da raiz e massa seca total, razão da massa seca da raiz e da parte aérea, clorofila a, b e total, aminoácidos e os açúcares solúveis foram avaliados aos 120 dias após o início da aplicação dos tratamentos. A pitaia vermelha é moderadamente tolerante a salinidade. O composto orgânico e estrume ovino atenuam os efeitos nocivos da salinidade nas mudas de pitaia vermelha. Sob condições de estresse salino, as plantas aumentam os níveis de aminoácidos e açúcares totais.

Abstract Red pitaya (Hylocereus costaricensis) is a promising species, with high cultivation potential due to the organoleptic and functional qualities of its fruits. However, irrigation water salinity can affect the crop yield. Therefore, materials rich in organic substances can minimize the damage caused by excess salts in soil and/or water. Thus, the objective of this study was to evaluate the influence of organic matter sources as attenuators of salt stress on the production and biochemical responses of red pitaya seedlings. A completely randomized design in 4 × 5 factorial scheme, with five sources of organic matter (humus, sheep manure, biofertilizer, organic compost and sand + soil) and four salinities (0.6, 2.6, 4.6 and 6.6 dS m-1) with four replicates and two plants per plot was used. The shoot length, root length, cladode diameter, number of cladodes, number of sprotus, root volume, shoot dry mass, root dry mass and total dry mass, root and shoot dry mass ratio, chlorophyll a, b and total, amino acids and soluble sugars were evaluated at 120 days after the treatments began to be applied. Red pitaya is moderately tolerant to salinity (ECw from 4.0 to 6.0 dS m-1). Organic compost and sheep manure attenuate the harmful effects of salinity on red pitaya seedlings. Under salt stress conditions, red pitaya plants increase their levels of proline, amino acids and total sugars.

Abstract This manuscript presents a method to produce sand-polymer bricks motivated by the need to reuse plastic waste and to reduce the embodied energy and carbon footprint associated with manufacturing. The method is designed to be simple: it involves a custom-built apparatus that simultaneously mixes and heats dry sand and recycled polypropylene granules, until the latter melt. The hot mixture is then compressed in a mold until the polymer rehardens, thereby producing a bonded brick upon extrusion. Bricks with 10% and 20% polymer content (i.e., by mass, PCg), were prepared with either a fine sand or a coarse sand. The voids of the PCg = 10% bricks were approximately halfway filled with hardened polymer, whereas the voids of the PCg = 20% bricks were nearly entirely filled. Bricks with PCg = 20% were found to be potential candidates for replacement of fired clay bricks, as these exhibited infiltration levels well below specification thresholds for fired clay bricks and strengths comparable to those reported for fired clay bricks. Furthermore, the embodied energy associated with sand-polymer bricks was calculated to be around a third of that required for fired clay bricks. In addition, the manufacture of sand-polymer bricks requires minutes, whereas that of fired clay bricks requires hours. The results gathered suggest that bricks produced by the proposed method have potential for replacement of fired clay bricks in applications wherein replacement is favorable.

Resumo Este manuscrito apresenta um método para produzir tijolos areia-polímero motivado pela necessidade de reutilizar resíduos plásticos e reduzir a energia incorporada e a pegada de carbono associada à fabricação. O método foi pensado para ser simples: envolve um aparelho customizado que mistura e aquece simultaneamente areia seca e polipropileno granular reciclado, até que estes derretam. A mistura quente é então comprimida num molde até que o polímero endureça novamente, produzindo assim um tijolo conformado após extrusão. Tijolos com teor de polímero de 10% e 20% (isto é, em massa, PCg), foram preparados com areia fina ou areia grossa. Os vazios dos tijolos PCg = 10% foram preenchidos aproximadamente até a metade com polímero endurecido, enquanto os vazios dos tijolos PCg = 20% foram quase totalmente preenchidos. Descobriu-se que os tijolos com PCg = 20% são candidatos potenciais para a substituição dos tijolos de barro cozidos, uma vez que apresentavam níveis de infiltração bem abaixo dos limites de especificação para tijolos de barro cozidos e resistências comparáveis às relatadas para tijolos de barro cozidos. Além disso, a energia incorporada associada aos tijolos areia-polímero foi calculada em cerca de um terço daquela necessária para os tijolos de argila cozidos. Além disso, a fabricação de tijolos areia-polímero leva minutos, enquanto a de tijolos de argila cozida leva horas. Os resultados obtidos sugerem que os tijolos produzidos pelo método proposto têm potencial para substituir os tijolos de barro cozido em aplicações onde a substituição é favorável.

ABSTRACT Bulk density (BD) is a soil physical property used as a soil quality indicator and variations in this measurement influence soil water content and carbon stock estimates. This study aims to compile a database of samples of bulk density, textural fractions, and organic carbon values, as well as evaluate the accuracy of published pedotransfer functions (PTF) that predict bulk density, and propose a hierarchical PTF to predict the bulk density of Brazilian Soils. The performance of eleven PTFs and the newly proposed PTFs were evaluated and compared using the root mean square error (RMSE) and coefficient of determination (R2) based on a testing soil database collected from the literature. We noticed a slight improvement in accuracy when organic carbon and coarse and fine sand fractions were included as predictors alongside silt and clay. The best results with existing PTFs were obtained by PTF-A in Tomasella and Hodnett (1998) (RMSE = 0.20 g cm–3) and PTF-F in Benites et al. (2007) (RMSE = 0.17 g cm–3). Our proposed PTFs use textural fractions and organic carbon as predictors in a hierarchical form. The proposed PTF-4, which uses fine sand, coarse sand, clay, and organic carbon, presented the lowest value for RMSE (0.14 g cm–3) for BD prediction.

Summary: The continuous changes in the use of soil for agricultural and livestock activities, as well the geographical location on sites affected by continuous wind currents, have caused changes in soil characteristics in a period of 40 years. To identify such changes, this study was performed in the north of the state of Zacatecas. The results of soil from 300 samples obtained in the laboratory analysis in 1976 were compared against an equal number of samples obtained in 2016. “Raster” images were generated by georeferencing the sampling sites and interpolating with “kriging”. The coinciding determinations between databases showed the differences between them by overlapping both images. The wind erosion was estimated and the levels of erosion associated with the sites where the changes occurred. The image analysis shows a matching area where sand content and soil pH increased. Such surface represents 401 907 ha of 2 118 000 ha covered by the images, where calcium has decreased in 98% of the surface, as well as potassium (59%), organic matter (58%), magnesium (49%) and sodium (35%) in 40 years, identifying areas of accumulation and soil loss associated with values of wind erosion. The prevailing SW winds that cause wind erosion were identified with values from 8 to 32 Mg ha-1 in 100 209 ha of accumulation and 233 587 ha of losses in 40 years. Of the total identified, 199 753 ha are agricultural areas and 202 154 are for livestock use. The identification of areas should help define plans and public policies for technological intervention.

Resumen: Los cambios continuos en el uso del suelo en actividades agrícolas y pecuarias, así como, la ubicación geográfica en sitios afectados por corrientes continuas de viento, han provocado cambios en las características del suelo en un periodo de 40 años. Para identificar tales cambios, se llevó a cabo el presente estudio en la región norte del estado de Zacatecas. Se utilizaron resultados de análisis de laboratorio de 300 muestras obtenidas en 1976 que fueron comparadas contra un número igual de muestras obtenidas en 2016. Al ubicar los sitios de muestreo se generaron imágenes “raster”, por interpolación con “kriging”. Se encontraron diferencias de las determinaciones coincidentes entre ambas bases de datos, al sobreponer ambas imágenes. Se estimó la erosión eólica de 2016 y se asoció los niveles de erosión con los sitios donde se presentaron los cambios. El traslape de imágenes muestra un área de coincidencia donde se incrementó el contenido de arena y el pH del suelo. Tal superficie representa 401 907 ha, de un total de 2 118 000 ha cubiertas por las imágenes. En ella se encontró que en 40 años ha disminuido el calcio en 98% de la superficie, así como, el potasio (59%), la materia orgánica (59%), magnesio (49%) y sodio (35%) con lo que se identificaron áreas de acumulación y pérdidas de suelo asociadas a valores altos de erosión eólica. Se identificaron los vientos predominantes del suroeste que provocan la erosión eólica con valores de 8 a 32 Mg ha-1 en 100 209 ha de acumulación y 233 587 ha de pérdidas en 40 años. Del total identificado 199 753 ha son áreas agrícolas y 202 154 son de uso pecuario. La identificación de áreas ayudará a definir planes y políticas públicas de intervención tecnológica.

Increasingly high levels of multidrug-resistant (MDR) pathogens have necessitated the discovery of novel bioactive compounds. For this reason, two actinomycetes strains, Streptomyces griseorubens and Streptomyces rochei, were isolated for the first time from the black sand shores of Kafr El Sheikh in Egypt, which is home to several large fish farms. Isolates were identified via phenotypic, biochemical and 16S rRNA sequence protocols. Both strains exhibited powerful antimicrobial activity against three serious MDR pathogens: Bacillus subtilis, Salmonella enteritidis and Pseudomonas aeruginosa. The bioactive compounds of isolates' filtrates were identified using gas chromatography-mass spectroscopy (GC-MS). For S. griseorubens, the detectable antibacterial compounds were hexanoic acid, 2-ethyl-, 2-ethylhexyl ester, n-Decane, hexadecanoic acid methyl ester, benzene acetic acid, ricinolic acid, and ethylparaben, while S. rochei secretes heptadecane, 2,6-dimethyl-, benzene acetic acid, dibutyl phthalate, octacosane, hexacosane, and vitamin A aldehyde. These results strongly encourage the use of these eco-friendly isolates as a biocontrol against MDR pathogens that attack fish farms. SIGNIFICANCE: Streptomyces spp. act as strong weapons for fighting multidrug resistance in pathogenic bacteria - one of the most important current threats to public health. They are additionally regarded as eco-friendly organisms that can be used as a biocontrol agent against infections that endanger fish farms

Resumen Introducción: La contaminación por microplásticos es un problema global en los ecosistemas marinos, con impacto sobre microorganismos y ecosistemas en varios niveles espaciales. Las playas arenosas son ambientes de deposición donde se tiende a acumular gran cantidad de microplásticos. La co-ocurrencia de meiofauna intersticial y microplásticos en granos de arena plantea la pregunta de que si la acumulación de microplásticos en sedimentos afecta la abundancia y composición de comunidades de meiofauna. Objetivo: Probar la hipótesis de que microplásticos afectan la meiofauna de playas arenosas urbanas. Métodos: Estudiamos las tres principales playas arenosas urbanas de Santa Marta, Colombia: El Rodadero, Bahía Santa Marta y Taganga. Estas son similares en morfología y presiones externas, y difieren de las otras playas de la región. En abril 2019 recolectamos 81 muestras de arena, distribuidas de manera equidistante en la zona intermareal (nivel intermareal superior, medio y bajo). Aplicamos modelos lineales generalizados de abundancia, y pruebas permutacionales multivariantes a la composición de comunidades. Resultados: Identificamos 17 grupos taxonómicos de meiofauna, y partículas de microplástico (principalmente fibras de 45-500 micras) distribuidos equitativamente a lo largo de las playas y niveles intermareales. Hubo más meiofauna en el nivel intermareal medio, y en sedimentos de grano mediano y fino. A niveles intermareales más bajos, sitios con más microplásticos tuvieron menos meiofauna. La abundancia de los microplásticos explicó el 39 % de la variación en comunidades de meiofauna a niveles intermareales bajos. Conclusión: La acumulación de microplásticos podría tener un impacto negativo sobre las comunidades de meiofauna intersticial. Esto no es de sorprender: si los microplásticos ocupan el mismo volumen físico que estos animales, estos podrían presuntamente modificar la estructura de sedimentos y la composición del agua intersticial.

Abstract Introduction: Pollution by microplastics is a global problem in marine environments, which impacts microorganisms and ecosystems at several spatial levels. Sandy beaches are depositional environments where microplastics tend to accumulate in large quantities. The co-occurrence of interstitial meiofauna and microplastics in sand grains raises the question on whether the accumulation of microplastics in the sediments affects the abundance and composition of the meiofaunal communities. Objective: To test the hypothesis that microplastics affect the meiofauna of urban sandy beaches. Methods: We studied the three main urban sandy beaches of Santa Marta, Colombia: El Rodadero, Santa Marta Bay, and Taganga. All are similar in morphology and external pressures, and differ from other beaches in the region. In April 2019 we collected 81 sand samples, equally distributed in the intertidal zone (upper, mid, and lower intertidal levels). We applied generalized linear models to abundance, and multivariate permutational tests to community composition. Results: We identified 17 taxonomic groups of meiofauna, and microplastic particles (mainly 45-500 micron fibres) evenly distributed across beaches and intertidal levels. There was more meiofauna at the mid intertidal level, and in fine and medium grain sediment. At the lower intertidal level, sites with more microplastics had less meiofauna. Abundance of microplastics explained 39 % of the variation in meiofaunal community composition at lower intertidal levels. Conclusions: The accumulation of microplastics might have a negative impact on these meiofaunal interstitial communities. This is not surprising: if microplastics occupy the same physical space as these animals, they might presumably modify the structure of sediments and the composition of interstitial water.

Resumen Introducción: La dispersión y depredación de semillas tienen efectos importantes en la diversidad de plantas y estructura de las comunidades. Los roedores participan en estos tipos de interacciones. Objetivos: Evaluar la remoción de semillas de Crescentia alata, Randia capitata y Zea mays por la ardilla Notocitellus adocetus, para determinar su efecto en estas especies de plantas, dispersando o depredando semillas. Métodos: Estudiamos 14 individuos de C. alata, 24 para R. capitata y 35 individuos para Z. mays. Observamos el forrajeo y usamos cámaras trampas para determinar la parte del fruto (semilla y/o pulpa) consumida y la intensidad de consumo por las ardillas. También colocamos trampas de arena fina (FST) para medir el porcentaje de remoción de semillas. Cuantificamos los frutos producidos por las especies estudiadas y el porcentaje de daño ocasionado por N. adocetus, mediante parcelas. Resultados: Notocitellus adocetus se alimenta de las semillas y pulpa de C. alata y Z. mays. La especie que tuvo mayor tasa de remoción y mayor porcentaje de daño fue C. alata. La especie con mayor porcentaje de remoción, mayor número de frutos y menor daño en las FST fue Z. mays. En las trampas de arena fina, R. capitata tuvo la menor remoción de semillas. Conclusiones: Notocitellus adocetus es considerada depredadora de semillas, no obstante, por su comportamiento y las características de los frutos de C. alata y R. capitata, este roedor podría dejar disponibles las semillas a dispersores secundarios de semillas.

Abstract Introduction: Seed dispersal and seed predation have important impacts on plant diversity and community structure. Rodents participate in both of these types of interactions. Objectives: To evaluate the removal of the seeds of Crescentia alata, Randia capitata, and Zea mays by the squirrel Notocitellus adocetus to determine how it affects these plant species, by dispersing or preying on their seeds. Methods: We studied 14 individuals for C. alata, 24 for R. capitata, and for Z. mays 35 individuals. We observed foraging and used camera traps to determine the part of the fruit (seed and/or pulp) consumed by the squirrels and the amount of fruit or seed consumed. We also placed fine sand traps (FST) to measure the percentage of seed removal. We quantified the fruits produced by the plant species studied and the percentage of damage caused by N. adocetus throughout the plots. Results: Notocitellus adocetus feeds on the seeds and pulp of C. alata and Z. mays. The species with the highest removal rate and the highest percentage of damage was C. alata. Zea mays was the plant species that had the highest percentage of removal from FST, the largest number of fruits, and the lowest percentage of damage. On FST, R. capitata had the lowest seed remotion. Conclusions: Notocitellus adocetus is considered a seed predator; however, due to its behavior and the characteristics of the fruits of C. alata and R. capitata, this rodent could make the seeds available to secondary seed dispersers.

Abstract The industrial waste peoduction causes environmental damage, so it is important to reintroduce them into the production cycle to promove a more sustainable development. The present study aims to investigate the use of residual marble powder as a filler and its effects on the production of concrete for interlocking pavements. For this purpose, natural sand was replaced by 15% and 25% marble powder, these percentages being scarce in the literature on the reuse of marble waste. The physical properties of the materials used were evaluated, and the mechanical and microstructural characteristics of the developed concrete were analyzed. It was observed that marble powder improves the workability of the mixture and reduces the quantity of empty spots in the concrete, resulting in a stronger, denser, and more homogeneous material. The axial compressive resistence achieved by the concrete was close to 40 MPa, meeting the Brazilian technical standard for interlocking pavement production. It was found that the integration of waste into the production cycle is beneficial for optimizing material properties, reducing the consumption of raw materials and the associated environmental impacts of their extraction.

Resumo A produção de resíduos industriais causa impactos ambientais, por isso é importante reintroduzi-los no ciclo produtivo para promover um desenvolvimento mais sustentável. O presente estudo teve o objetivo de investigar o uso do pó de mármore residual como fíler e seus efeitos na produção de concreto para pavimentos intertravados. Para isso, a areia natural foi substituída em 15% e 25% pelo pó de mármore, percentuais pouco usados na literatura de reaproveitamento de resíduos de mármore. Foram avaliadas as propriedades físicas dos materiais utilizados e as características mecânicas e microestruturais dos concretos desenvolvidos. Notou-se que o pó de mármore melhora a trabalhabilidade da mistura e reduz a quantidade de vazios no concreto, resultando em um material mais resistente, denso e homogêneo. As resistências à compressão obtidas pelos concretos foram próximas de 40 MPa, o que atende à norma técnica brasileira para produção de pavimentos intertravados. Verificou-se que a inserção de resíduos no ciclo produtivo é benéfica por otimizar propriedades dos materiais, reduzir o consumo de matérias-primas e os impactos ambientais associados à sua extração.