Small plastic particles are considered emerging pollutants, and this has motivated a considerable number of studies to establish their environmental consequences. At present, the study of the effects ...of nanoplastics (NPs) on aquatic organisms is still scarce, especially in organisms from higher trophic levels such as fish. This review describes the effects reported in different fish species after exposure to plastic particles smaller than 100 nm. Studies show that NPs can adversely affect fish at different stages of development, with reported accumulation in tissues, decreased locomotor and foraging activities, effects on growth and the immune system and alterations on lipid metabolism and neurotoxicity. However, mortality, effects on hatching success or malformations related to NPs have not been reported to this date.
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•The study of the effects of nanoplastics (NPs) on fish is still scarce.•This review describes the effects reported in different fish species after exposure to plastic particles smaller than 100 nm.•Future studies should expand to polymers most likely to be found in the environment.•Detection of NPs in edible fish parts or mollusks is a pressing issue.
Tawera elliptica is a small size (baby) clam with an export fishery in southern Chile. The species is dioecious with external fertilization and without sexual dimorphism. The aim of this work was to ...optimize broodstock conditioning, induce spawning and describe embryonic development until the early larval stage in a hatchery. Broodstock were conditioned at 3 treatments (with/without sand; water circulation) for 48 days. The clams were fed with a mixed diet of macroalgae, with a daily ration of 250,000 cells/ml. Broodstock response was quantified using condition index and gonad development stages (histological techniques). For spawning induction, physical and biological methods were tested. The best response was achieved in males with physical induction. Histological analysis showed that the water circulation system treatment exhibited the highest percentage of maximum maturity. A fertilization ratio of 500:1 sperm:oocyte was used. The incubation was carried out in 3‐L containers with filtered seawater at 10.7 ± 0.9°C without aeration. Observations, measurements and the duration of each embryonic and larval stage were recorded. The oocyte has a prominent gelatinous layer (= jelly coat) that disappears between the gastrula and trochophore stages. The status of the D‐larval stage was reached at 107 h post fertilization with a mean valve length of 91.4 ± 8.9 µm. This is the first record of the complete embryonic development of this baby clam until the early larval stage and the conditioning in a water circulation system for 48 days are suitable for the species.
Harmful Algal Blooms (HABs) have been classified depending on the causative organism and its impacts: non-toxic HAB (microalgae capable of affecting tourism and causing oxygen deficiency, which ...generates mortality of marine organisms), toxic HAB (microalgae capable of transferring toxins to the food chain), and ichthyotoxic HAB (microalgae capable of generating mechanical damage in fish). HABs represent a worldwide problem and have apparently increased in frequency, intensity, and geographic distribution at different latitudes. This review details the occurrence of HAB events in the Southeast Pacific, Chile, over a 65-year period, analysing two of the three types of HAB described: toxic and ichthyotoxic HABs. For this, we conducted a review from many different scientific sources and from the written press and social media, that have mentioned HAB events in the country. In Chile, the microalgae involved in HAB events are dinoflagellate (52%), diatoms (33%) and silicoflagellate (10%), with a total of 41 species and/or genera described in the literature. A total of 501 HAB events were recorded in Chile between 1956 and 2021, where 240 (47.9%), 238 (47.5%), 14 (2.7%), 8 (1.5%) and 1 (0.2%) event were caused by diatoms, dinoflagellate, silicoflagellate, raphidophycean and haptophyte, respectively. An apparent increase in the frequency of HAB events is observed since the first record in 1956, with a maximum of 46 events during the years 2017 and 2019. The highest incidence in fish is caused by the group of silicoflagellate, raphidophycean and haptophyte (23 events), where 10 events caused mortalities in salmon with an incidence rate of 43.4%. Unlike what is observed with diatoms and dinoflagellate, the events associated with these groups are less frequent, but hold a much higher salmon mortality rate. During the last 65 years, HAB’s geographic extent shows an apparent trend to increase south-to-north. However, the identification of events is closely linked to the areas where much of the country’s aquaculture is located and, therefore, it could be biased. In turn, it is observed that the apparent increase in HAB events could be associated with a greater monitoring effort after major events (e.g., after the 2016 HAB event). On the other hand, it is also recognized a lack of knowledge about harmful algae throughout the Chilean Humboldt Current system, particularly in the northern regions, such as Atacama and Coquimbo. Therefore, the total number of blooms that have occurred in fjords and channels, particularly those that have caused minor economic impacts for artisanal fishermen and the salmon and mussel farming sector, might be underestimated.
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•Most relevant findings from 374 Tawera elliptica clams examined were intracellular microcolonies of bacteria (IMC) in digestive gland and intestine, and an intraoocytic ...microsporidian.•Scanning electron images of histological sections of IMC and the Steinhausia-like intraoocytic microsporidian.•No OIE listed pathogens detected.•No disease risks for the cultivation of this clam at actual prevalences and infection intensities.
Tawera elliptica (commonly known as “Almeja Juliana”, is a venerid clam that inhabits sandy bottoms and is distributed from Valparaíso on the Pacific coast up to the Mar del Plata area along the Atlantic coast. Harvests of this clam have declined substantially over the last decade. Therefore, an analysis of common parasites and pathological conditions of this clam was undertaken along with histopathology. Monthly samples were prepared for routine histology for examination under light and electron microscopy. T. elliptica has a sex ratio of 1:1 and the relationship between the shell length and the wet tissue weight is not significantly different between females and males. The maximum values for de condition index and meat yield were found during the austral winter. The following parasites (and their overall prevalence) were detected: intracellular microcolonies of bacteria in digestive gland (22.9%), intestinal epithelium (9.3%) and gills (3.17%), an unidentified cyst in gills (59,3%), a Steinhausia-like intraoocytic microsporidian (5.2%), Gregarine spores (41.3%), ciliated protozoa (16.7%), two metazoa, a Paravortex like flatworm (4.3%), and a digenean trematode (8%). The monthly mean intensity of the most relevant parasites was between 2.3 and 35.6 for digestive gland intracellular microcolonies of bacteria (IMC), 0–5.1 for intestinal epithelium IMC, 0–2 for branchial IMC and 0 – 48 for intraoocytic microsporidium. The prevalence and the infection intensity were low-to very low, and no World Organisation for Animal Health OIE listed parasite was detected. It is concluded that this is a healthy clam, and no disease risks for the cultivation are visualized at present. However, IMC at high prevalence and intensities of infection could be potentially impactful, and the intraoocytic microsporidian could jeopardize reproduction if present in high intensities of infection.
De acuerdo a la ciencia de la ocupación y la justicia ocupacional, la participación e inclusión en ocupaciones significativas, resulta fundamental para el desarrollo de las personas y de las ...comunidades, sin embargo, esta inclusión no siempre se ve favorecida en todos los espacios públicos. El ámbito de la educación ha desarrollado un avance importante en esta materia principalmente en sus niveles primarios, potenciando proyectos como el de integración escolar, con lo cual se ha dado espacio a alumnos en situación de discapacidad. Estos proyectos no se han incorporado a la educación superior, por lo cual los alumnos deben crear sus propias estrategias para la inclusión ya que los ambientes tanto físicos como sociales no siempre están preparados para responder a las necesidades particulares de los alumnos con distintas discapacidades y otorgar un real y equitativo acceso a la educación. Esta investigación busca obtener mayores antecedentes acerca de los procesos de inclusión y adaptación de un grupo de jóvenes con discapacidad en la Universidad de Magallanes, con el fin de aportar de manera concreta a estas políticas. Para esto, se utilizó la metodología cualitativa, considerando la experiencia de 15 estudiantes, de diversas carreras y con distinto tipo de discapacidad. Dentro del estudio, aparecen como relevantes los facilitadores vinculados al entorno, referente a ayudas técnicas, familia y red social, y por otra parte, las características personales de los estudiantes, como por ejemplo la capacidad de resiliencia que les permite sobreponerse y responder con estrategias personales a los desafíos y barreras existentes. Por lo anterior, aparecen necesidades que invitan a potenciar el cambio de paradigma de la inclusión en el ámbito educativo, que contemple un equilibrio real entre considerar los requerimientos especiales para la equidad y a su vez fomentar el trato igualitario que promueva la dignidad de las personas con discapacidad.
Since 2010, Chile has experienced one of the most severe droughts over the last century, the so-called mega-drought (MD). The MD conditions, combined with intensive agricultural activities and the ...current water management system, have led to water scarcity problems in Mediterranean and Semi-arid regions of Chile. An emblematic case is the Petorca basin, where a water crisis is undergone. To characterize this crisis, we analyzed water provision by using tree-ring records, remote sensing, instrumental data, and allocated water rights within the basin. Results indicate that the MD is the most severe dry period over the last 700-years of streamflow reconstruction. During the MD, streamflow and water bodies of the upper parts of the basin have been less affected than mid and low areas of this valley, where consumptive withdrawals reach up to 18% of the mean annual precipitation. This extracted volume is similar to the MD mean annual precipitation deficits. The impacts of the current drought, along with the drier climate projections for Central Chile, emphasize the urgency for faster policy changes related to water provision. Climate change adaptation plans and policies should enhance the current monitoring network and the public control of water use to secure the water access for inhabitants and productive activities.
Irisin is an adipomyokine involved in white adipose tissue browning, therefore, could be a key protein in metabolic health. However, exercise effects on irisin in subjects with overweight and/or ...obesity are conflicting. Therefore, this systematic review aims to search and analyse the literature available on this topic. From three databases: PubMed, ScienceDirect, and Medline, clinical studies published between 2010 and 2021 were considered. From 134 found, 14 studies were included. Only six reported plasma increases after exercise (~1.2 to 3-fold from pre-exercise levels). In addition, only 1 reported significant increases in skeletal muscle irisin mRNA levels (~2-fold). Also, irisin was measured from subcutaneous adipose tissue and saliva, where a ~2-fold increase in its protein levels was found in the latter. Exercise seems to increase the circulatory concentrations of irisin in subjects with overweight or obesity. However, this response is highly variable, therefore, a more integrative approach is urgently needed.
Water allocation under climate change Barría Pilar; Sandoval, Ignacio Barría; Guzman, Carlos ...
Elementa (Washington, D.C.),
05/2021, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Chile is positioned in the 20th rank of water availability per capita. Nonetheless, water security levels vary across the territory. Around 70% of the national population lives in arid and semiarid ...regions, where a persistent drought has been experienced over the last decade. This has led to water security problems including water shortages. The water allocation and trading system in Chile is based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms, where the volume to be granted as permanent and eventual WURs is calculated from statistical analyses of historical streamflow records if available, or from empirical estimations if they are not. This computation of WURs does not consider the nonstationarity of hydrological processes nor climatic projections. This study presents the first large sample diagnosis of water allocation system in Chile under climate change scenarios. This is based on novel anthropic intervention indices (IAI), which were computed as the ratio between the total granted water volume to the water availability within 87 basins in north-central and southern Chile (30°S–42°S). The IAI were evaluated for the historical period (1979–2019) and under modeled-based climatic projections (2055–2080). According to these IAI levels, to date, there are 20 out of 87 overallocated basins, which under the assumption that no further WURs will be granted in the future, increases up to 25 basins for the 2055–2080 period. The results show that, to date most of north-central Chilean catchments already have a large anthropic intervention degree, and the increases for the future period occurs mostly in the southern region of the country (approximately 38°S), which has been considered as possible source of water for large water transfer projects (i.e., water roads). These indices and diagnosis are proposed as a tool to help policy makers to address water scarcity under climate change.
RESUMEN: El ser humano en el transcurso de la evolución ha cambiado la percepción de la alimentación dejando de lado el consumo de carne y sus derivados por factores éticos y morales, donde se sabe ...la dieta tiene gran relevancia en la salud general, siendo un factor de riesgo para la aparición de diversas enfermedades motivo por cual la saliva se ha utilizado como instrumento de diagnóstico Describir y comparar el índice de Dieta mediterránea según pH salival en mujeres estudiantes de Odontología de entre 20 a 30 años. Estudio descriptivo transversal comparativo. Participaron 17 mujeres adultas seleccionadas por criterio no probabilístico en la carrera de Odontología, quienes fueron evaluadas en su índice de Dieta mediterránea y pH salival. Se aplicó la prueba T de Student para muestras independientes y U Mann-Whitney para comparar características entre grupos en función del pH salival. Existen diferencias significativas entre grupos para la frecuencia de consumo de cereales integrales (p = 0,026), carnes magras (p = 0,021) y pH salival (p < 0,001). Existe un predominio hacia la baja adherencia a una dieta mediterránea, existiendo diferencias significativas en la frecuencia de consumo de cereales integrales y carnes magras, siendo el consumo de estos un indicador del riesgo de la cavidad oral determinado por pH.
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