RESUMEN
The rhizosphere microbiome plays a crucial role in the ability of plants to colonize and thrive in stressful conditions such as drought, which could be decisive for the success of exotic plant invasion in the context of global climate change. The aim of this investigation was to examine differences in the composition, structure, and functional traits of the microbial community of the invader Nicotiana glauca R.C. Graham and native species growing at seven different Mediterranean semiarid locations under two distinct levels of water availability, corresponding to the wet and dry seasons. The results show that the phylum Actinobacteriota was an indicator phylum of the dry season as well as for the community of N. glauca. The dominant indicator bacterial families of the dry season were 67-14 (unclassified family), Pseudonocardiaceae, and Sphingomonadaceae, being relatively more abundant in the invasive rhizosphere. The relative abundances of the indicator fungal families Aspergillaceae (particularly the indicator genus Aspergillus), Glomeraceae, and Claroideoglomeraceae were higher in the invasive rhizosphere. The relative abundance of mycorrhizal fungi was higher in the invasive rhizosphere in the dry season (by about 40 % in comparison to that of native plants), without significant differences between invasive and native plants in the wet season. Bacterial potential functional traits related to energy and precursor metabolites production and also biosynthesis of cell wall, cofactors, vitamins, and amino acids as well as catabolic enzymes involved in the P cycle prevailed in the invasive rhizosphere under drought conditions. This study shows that the pronounced and beneficial shifts in the microbiome assembly and functions in the rhizosphere of N. glauca under conditions of low soil water availability can represent a clear advantage for its establishment.
Asunto(s)
Sequías , Especies Introducidas , Microbiota , Nicotiana , Rizosfera , Microbiología del Suelo , Nicotiana/microbiología , Estaciones del Año , Ecosistema , Micorrizas/fisiologíaAsunto(s)
Antivirales , Bencimidazoles , Quimioterapia Combinada , Hepatitis C Crónica , Pirrolidinas , Quinoxalinas , Ribavirina , Terapia Recuperativa , Sulfonamidas , Humanos , Masculino , Persona de Mediana Edad , Ácidos Aminoisobutíricos , Antivirales/uso terapéutico , Antivirales/administración & dosificación , Bencimidazoles/uso terapéutico , Ciclopropanos/uso terapéutico , Hepacivirus/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , Lactamas Macrocíclicas/uso terapéutico , Leucina/análogos & derivados , Leucina/uso terapéutico , Prolina/análogos & derivados , Prolina/uso terapéutico , Pirrolidinas/uso terapéutico , Quinoxalinas/uso terapéutico , Ribavirina/uso terapéutico , Ribavirina/administración & dosificación , Sulfonamidas/uso terapéuticoRESUMEN
When necessary, sea turtles are held captive for veterinarian care and research purposes. Protocols and basic guidelines have been described for husbandry of sea turtles with veterinarian needs but not considering physiological indicators of animal welfare. Because all sea turtle are imperiled species, monitoring their welfare is important. The aim of this study was to standardize husbandry protocols for loggerhead (Caretta caretta) juveniles held under seminatural conditions, based on circulating concentration of plasma corticosterone (Cort) and behavior. Two experiments were performed to analyze physiological and behavioral responses of the animals facing changes in stocking density and different dry-docking times. Cort analyses suggested that the number of animals per tank can be modified occasionally, without affecting their health and welfare. However, dry-docking time should be < 30 min, as indicated by the significant elevation of circulating Cort at ≥ 30 min, rising from 1.51- ng/ml to 5.28-ng/ml. Protocols tested did not affect behavioral responses, except for the breaths per move, which increased while Cort increased, despite differences exhibited by experimental animals in behavioral responses according to daily times (morning vs afternoon) and the sex of the animals.
Asunto(s)
Crianza de Animales Domésticos , Bienestar del Animal , Conducta Animal , Corticosterona , Estrés Fisiológico , Tortugas , Animales , Tortugas/fisiología , Tortugas/sangre , Crianza de Animales Domésticos/métodos , Femenino , Masculino , Corticosterona/sangre , Densidad de Población , Factores de TiempoRESUMEN
Colorectal cancer (CRC) and periodontitis have recently been related due to the higher incidence of CRC in periodontal patients and the involvement of periodontal pathogens in carcinogenesis, suggesting that leakage from the oral cavity to the gut occurs. However, the magnitude of this pass-through in healthy individuals is controversial, and the effect that periodontitis could play in it is understudied. To evaluate the rate of bacterial leakage from the oral cavity to the gut, we analyzed the microbial composition of saliva, subgingival plaque, and fecal samples in healthy individuals without gastrointestinal disorders, including 20 periodontitis patients and 20 oral healthy controls, using PacBio full-length 16S rRNA gene sequencing. As expected, we observed a higher abundance of periodontal pathogens in the subgingival plaque and saliva of periodontal patients. In contrast, no significant differences were found between the fecal samples of both groups, implying that gut samples from periodontal patients were not enriched in periodontal pathogens. Fusobacterium nucleatum, a biomarker of CRC, was not found in the fecal samples of any participant. Our study does show a small leakage of some oral bacteria (mainly streptococci) to the gut, regardless of periodontal health status. Future studies should test whether other host factors and/or the preexistence of a gut disorder must be present in addition to periodontitis to promote the colonization of the gut by oral pathogens. The absence of periodontal pathogens in feces supports the idea that these bacteria could be used as biomarkers of intestinal disorders, including CRC.
Asunto(s)
Placa Dental , Periodontitis , Humanos , ARN Ribosómico 16S/genética , Periodontitis/microbiología , Bacterias , Placa Dental/microbiología , Fusobacterium nucleatumRESUMEN
Introducción: Las Tecnologías de la Información y Comunicación (TICs) son un recurso a través del cual los profesionales de la salud pueden proporcionar apoyo y asesoría a distancia. Objetivo: Describir las experiencias de una cuidadora familiar (CF) con el uso de las TICs en la implementación de una intervención educativa como apoyo para su autocuidado y el cuidado del adulto mayor (AM). Metodología: Estudio de caso con abordaje cualitativo. Una pasante de la licenciatura en Enfermería y Obstetricia implementó una intervención educativa en una CF del 15 diciembre 2020 al 25 junio 2021, periodo de pandemia por COVID-19. La recolección de datos se realizó a partir de entrevistas a profundidad, mensajes de texto y voz de WhatsApp, así como por observación. Se realizó análisis de contenido tipo temático según de Souza Minayo. Resultados: Se identificó el teléfono celular como el dispositivo más utilizado, las funciones de videollamada y mensaje de voz de WhatsApp como las herramientas más útiles y preferidas por la CF, y las infografías y videos como los materiales educativos más adecuados para esta población. Limitaciones: Solo se incluyó una CF y un AM, lo cual puede generar un sesgo de respuesta, ya que la CF quizás estuvo más motivada y dispuesta a participar que otros cuidadores hipotéticos. Valor: Implementar un nuevo canal de comunicación entre el profesional de enfermería, el AM, la CF y otros familiares. Conclusiones: El uso de las TICs fue aceptado por la CF para recibir capacitación en su autocuidado y cuidado del AM.
Introduction: Health professionals can use Information and Communication Technologies (ICTs) to provide support and advice at a distance. Objective: Description of the experiences of a family caregiver (FC) with the use of ICTs in the implementation of an educational intervention to support her self-care and the care of the Older Adult (OA). Methodology: Case study with qualitative approach. An undergraduate intern in Nursing and Midwifery implemented an educational intervention with a FC from December 15, 2020 to June 25, 2021, during the covid-19 pandemic. Data collection was gathered with in-depth interviews, Whatsapp text and voice messages, as well as direct observation. Thematic type content analysis was performed according to de Souza Minayo. Results: The cell phone was identified as the most used device, Whatsapp video call and voice message functions as the most useful and preferred tools by the FC, and infographics and videos as the most appropriate educational materials for this population. Limitations: Only one female FC and one male OA were included in this study. This may generate response bias, as the FC was perhaps more motivated and willing to participate than other hypothetical caregivers. Value: Implementation of a new communication channel between the nursing professional, the OA, the FC, and other family members. Conclusions: Training in the use of ICTs was accepted by the FC to improve her self-care and care of the OA.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Anciano , Adulto Joven , Cuidadores , Anciano , Teléfono Celular , Tecnología de la Información , Enfermeras y EnfermerosRESUMEN
Vitellogenin (VTG), an egg yolk precursor, is abnormally produced by male and juvenile oviparous species after exposure to estrogens. Plasma VTG in loggerhead sea turtles (Caretta caretta) helped us understand their reproductive maturation and investigate it as a biomarker of contaminant exposure. The presence of VTG was screened in plasma from 404 loggerheads from the northwestern Atlantic Ocean using a freshwater turtle antibody in western blots. The concentrations of VTG were semiquantified using band intensities calibrated to results from a loggerhead antibody enzyme-linked immunoassay. The detection and concentrations of VTG were in (from highest to lowest): nesting females, in-water adult females, subadult females, smaller females, unknown sex, and males. Loggerheads from this region begin vitellogenesis at â 77 cm straight carapace length. We classified VTG expression as abnormal in nine male or juvenile turtles. Organochlorine contaminant (OC) concentrations were measured in blood and/or fat biopsies of some turtles. One abnormal VTG female had the second highest fat polychlorinated biphenyl (PCB) and 4,4'-dichlorodiphenyldichloroethylene concentrations compared among 43 VTG-negative juveniles. The nine VTG-abnormal turtles had average blood PCB concentrations 8.5% higher, but not significantly different, than 46 VTG-negative juveniles (p = 0.453). In turtles less than 77 cm, blood PCB concentrations were significantly, but weakly, correlated with semiquantified VTG concentrations (tau = 0.1, p = 0.004). Greater blood OC concentrations were found in adult females than in males, which motivated the creation of a conceptual model of OC, VTG, and hormone concentrations across a reproductive cycle. A decision tree is also provided incorporating VTG as a sexing tool. Abnormal VTG expression cannot conclusively be linked to endocrine disruption caused by these OC concentrations. Studies should further investigate causes of abnormal VTG expression in wild sea turtles. Environ Toxicol Chem 2023;42:1309-1325. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
Asunto(s)
Bifenilos Policlorados , Tortugas , Animales , Femenino , Masculino , Vitelogeninas/metabolismo , Tortugas/metabolismo , Bifenilos Policlorados/metabolismo , Anticuerpos/metabolismo , Estrógenos/metabolismoRESUMEN
The goal of this work was to evaluate the effects of fermented sugar beet residue and inoculation with a native arbuscular mycorrhizal (AM) fungus, Funneliformis mosseae (Nicol. and Gerd.) Gerd. and Trappe, or a native bacterium, Bacillus cereus Frankland & Frankland, alone or in combination, on the establishment of Lygeum spartum L. seedlings grown in a mine tailing under semiarid conditions. We conducted a field study to analyse root and shoot dry biomass, shoot nutrient contents, mycorrhization, plant nitrate reductase (NR) and acid phosphomonoesterase activities, soil enzyme activities and aggregate stability. Ten months after field transplanting, it was found that the three experimental factors had interacted synergistically with regard to shoot and root biomass, with increases of about 410% and 370%, respectively relative to plants in the untreated soil. The treatment combining all three factors increased the root content of all heavy metals, and the levels of nitrogen (N), phosphorus, potassium and NR activity in shoot tissues, whereas it decreased root acid phosphomonoesterase activity. Soil dehydrogenase, protease and ß-glucosidase activities, total N content and aggregate stability were increased by the combined treatment. In conclusion, the combination of the organic amendment, the native AM fungus and the native bacterium can be regarded as a suitable tool for phytostabilization with L. spartum due to its ability to enhance the tolerance of plants to heavy metals, improve the plant nutritional status and increase the soil microbial function related to the C cycling.
Asunto(s)
Reflujo Gastroesofágico , Metales Pesados , Micorrizas , Contaminantes del Suelo , Bacillus cereus , Microbiología del Suelo , Suelo/química , Contaminantes del Suelo/análisis , Metales Pesados/análisis , Monoéster Fosfórico Hidrolasas , Raíces de Plantas/químicaRESUMEN
Tortuguero, Costa Rica is considered the second largest green turtle (Chelonia mydas) rookery in the world. By 1950, Tortuguero was one of the sites with the greatest take of green turtles in the Caribbean. Currently, Tortuguero is a worldwide example for ecotourism-based on sea turtle conservation. However, illegal take of nesting turtles still occurs. We aimed to describe the illegal take at Tortuguero, estimating the minimum number of sea turtles taken using data collected during daily and weekly track surveys from 2005 to 2021. Additionally, we conducted 12 semi-structured interviews with key informants to obtain a better understanding of this activity. We documented 735 nesting turtles illegally taken at Tortuguero, being the green turtle the most affected species; these findings were also supported by our interviewees. Respondents stated that in Tortuguero the take of sea turtles has always occurred and traditions regarding sea turtle meat consumption are still present, even though it is considered shameful in the village. However, our interviewees affirmed that most of the sea turtles taken are traded to other locations away from Tortuguero. Our findings represent the minimum of illegal take (documented only at the beach), as not all the sea turtles taken were observed. Finally, despite long-standing conservation efforts carried out in Tortuguero, further changes in the National Park's management plans are needed, including more personnel and increased law enforcement. This may be necessary to reduce the impact on the Tortuguero green turtle nesting population in the near future.
Asunto(s)
Tortugas , Animales , Región del Caribe , Costa Rica/epidemiología , Comportamiento de Nidificación , Conservación de los Recursos Naturales , CrimenRESUMEN
Costa Rica hosts two renowned olive ridley (Lepidochelys olivacea) arribada beaches: Nancite and Ostional. In addition, the country hosts a third nascent arribada beach in Corozalito. We documented the frequency of arribada events in Corozalito (9°50'55.40â³ N; 85°22' 47.67â³ W) from 2008 to 2021 and the abundance of egg-laying females during 12 arribadas. Moreover, we report on tag recaptures at Corozalito that were initially deployed at other nesting beaches in Costa Rica. Finally, we estimated incubation temperature, and performed quadrat and nest excavations to estimate hatching rates. We registered 29 arribadas at Corozalito since 2008, all between August and January. We estimated more than 150,000 olive ridleys nested during 12 arribadas from 2019 to 2021. Mean hatching success was 65% in quadrats and 59% for in situ marked nests. The mean incubation temperature was 32.3 °C. We found turtles tagged at other locations on the Pacific coast of Costa Rica nesting at Corozalito, providing evidence of philopatric plasticity. We suggest nascent arribada rookeries form rapidly via recruitment from regional turtle aggregations. Our findings show that hatching success is far higher at Corozalito than Ostional or Nancite. Continued monitoring of nesting dynamics at this site may shed light upon the mechanisms that rule how arribada beaches are born and evolve. Corozalito offers a unique opportunity to study and understand the arribada phenomenon and warrants official protection under official National Wildlife Refuge status.
RESUMEN
Antecedentes y objetivos: El control postural es un proceso dinámico que permite a los individuos mantener una posición estable mientras interactúa con la tarea y el medio ambiente. El control postural del niño con parálisis cerebral se encuentra afectado. El objetivo de este estudio fue describir los patrones motores y las estrategias de control postural usadas por un niño con parálisis cerebral (PC) discinética, severamente comprometido, al tratar de realizar una tarea motora simple. Materiales y métodos: Niño de 9 años con diagnóstico médico de PC; se encuentra en silla de ruedas y presenta imposibilidad para el control postural en sedestación y para el movimiento funcional de las extremidades superiores. La tarea motora propuesta consistió en tratar de presionar 2 interruptores que hacían funcionar un robot LEGO®, como respuesta a las recomendaciones dadas por el terapeuta. Se realizó la actividad por 15min una vez a la semana, durante 8 semanas. Resultados: El niño logró encontrar patrones de movimiento y estrategias de control postural que le permitieron realizar la tarea motora de manera eficiente. El niño asistió a todas las sesiones programadas y no se produjeron eventos adversos. Conclusión: La atención, la retroalimentación visual, la velocidad del movimiento y el desplazamiento del centro de gravedad fueron algunos de los patrones de movimiento y estrategias de control postural usadas, para realizar de manera exitosa la tarea motora. La propuesta de una actividad motora acorde a la condición de discapacidad, puede ser fuente de motivación y persistencia en su realización.(AU)
Background and objectives: Postural control is a dynamic process that allows individuals to maintain a stable position while interacting with task and environment. The postural control of the child with cerebral palsy is affected. This study's objective was to describe the motor patterns and postural control strategies used by a severely compromised child with dyskinetic CP when trying to perform a simple motor task. Materials and methods: A 9-year-old boy with a medical diagnosis of CP; he is in a wheelchair and presents an inability to control posture in a sitting position and functional movement of his upper limbs. The proposed motor task consisted of trying to press two switches that operated a LEGO® robot in response to the therapist's recommendations. The activity was carried out for 15 minutes once a week, for eight weeks. Results: The child was able to find movement patterns and postural control strategies that allowed him to perform the motor task efficiently. The child attended all scheduled sessions and no adverse events occurred. Conclusions: Attention, visual feedback, speed of movement and displacement of centre of gravity were some of the movement patterns and postural control strategies used to successfully perform the motor task. The proposal of a motor activity according to the disability condition, can encourage motivation and persistence in its performance.(AU)
Asunto(s)
Humanos , Masculino , Niño , Postura , Parálisis Cerebral , Niño , Robótica , Trastornos del Movimiento , Especialidad de FisioterapiaRESUMEN
Exotic invasive plants may shape their own rhizosphere microbial community during global invasions. Nevertheless, the impacts of such plant invasions on the functional capacities of soil microbial communities remain poorly explored. We used an approach at a broad geographical scale to estimate the composition and abundance of the fungal functional groups, as well as the bacterial metabolic functions, associated with the rhizospheres of Carpobrotus edulis (L.) L. Bolus and the predominant native plants in coastal ecosystems located in different geographical regions. We used the ASV method to infer the potential functions of the soil microbial community with the PICRUSt2 and FUNGuild tools. The predictive functional profiling of the bacterial communities differed between the rhizospheres of the invasive and native plants, regardless of the biogeographic location of the invaded soil. Some predicted pathways related to the biosynthesis of nucleotides such as ppGpp and pppGpp, lipids, carbohydrates and secondary metabolites and the degradation of organic matter were enriched in the C. edulis rhizosphere. Moreover, the invasive microbiota was characterised by a greater richness and diversity of catabolic enzymes involved in nutrients cycling and higher relative abundances of saprotrophs and pathotrophs. Invasion by C. edulis promoted a shift in the potential functional versatility of the soil microbial communities, which can cope with nutrient limitations and biotic stress, and can favour the establishment of the invasive plant, but also alter the functioning and stability of the invaded ecosystems.
Asunto(s)
Microbiota , Suelo , Especies Introducidas , Rizosfera , Microbiología del SueloRESUMEN
Sea turtles are among several hundred species whose sex is determined by incubation conditions during critical developmental periods. Consequently, these marine reptiles may be vulnerable to global climate change, and under the assumption of continued climate warming, numerous studies pose dire predictions for future populations based primarily on hatchling sex ratio data. Alternatively, as long-lived species that take decades to reach maturity, without inherent coping mechanisms for such change, sea turtles could not have persisted across geological epochs. Globally, loggerhead Caretta caretta [Linnaeus, 1758] sea turtles occupy temperate zones, with ontogenetic development that spans the entirety of gyres associated with respective ocean basins. The largest rookery for this species occurs in the Northwest Atlantic Ocean (NWA) population, where a 30-year cycle in annual nest counts is reported through 2018. Complementary studies document a lagged association between these annual nest counts and the Atlantic Multidecadal Oscillation (AMO); however, the underlying mechanism for this association remains elusive. Therefore, objective 1 evaluated the effect of AMO-mediated cohort resonance on the demographic structure of a theoretical neritic assemblage under variable cohort abundance and female proportion but stable annual survival during 165-year runs (i.e., extent of AMO data). For objective 2, blood samples were used to assign sex to 2217 loggerhead sea turtles captured by research trawling (2000 to 2019) on the inner continental shelf from St. Augustine, FL (29.9°N) to Winyah Bay, SC (33.1°N). Shorter oceanic duration of less female-biased cohorts from the AMO cold phase synchronized peak adult male and adult female co-occurrence during subsequent warm phases three decades later. Grand sex ratio predicted from testosterone was 67% female (n = 1484), with a slight temporal female decline. Our findings suggest greater population sex ratio plasticity than predicted solely from terrestrial nesting data.
Asunto(s)
Tortugas , Animales , Océano Atlántico , Cambio Climático , Miedo , Femenino , Masculino , Razón de Masculinidad , Estados UnidosRESUMEN
BACKGROUND: The S-Index assessed by means of electronic devices is a measure of Inspiratory Muscle Strength (IMS) that highly correlates with the maximal inspiratory pressure (MIP). The variables involved when using regression models for the prediction of IMS/MIP depend on both the sample characteristics and the device or protocol used. In light of the scarce information on the influence of physical activity (PA) on IMS in healthy older adults (OA), together with the incorporation of new assessment devices, the objectives of this research are: 1) to determine which factors influence the IMS in a group of trained OA, using a portable electronic device; and 2) to propose a regression model to improve its assessment and training. METHODS: One hundred and fifty-nine individuals were assessed for body composition, lung capacity, IMS, and PA. A total of 92 individuals (72.73 ± 4.99 years) were considered for the final sample. RESULTS: Using age, sex, and weight as control variables, forced expiratory volume in the first second (FEV1) is the variable which is most likely to be included in the model (80%), without physical fitness appearing to be decisive. In the absence of spirometric variables, cardiorespiratory fitness (6MWT) takes on this role in a predictive model (16%). CONCLUSIONS: This is the first study proposing IMS predictive formulas considering spirometry and/or physical fitness results for a Spanish, healthy, and trained OAs population. A predictive formula including also the spirometric variables (mainly the FEV1) might better predict the inspiratory muscle strength. In addition, physical and respiratory functions confirm to be different, so it is necessary for the inspiratory muscles to be trained in a specific way.
Asunto(s)
Ejercicio Físico/fisiología , Fuerza Muscular/fisiología , Músculos Respiratorios/fisiología , Anciano , Anciano de 80 o más Años , Composición Corporal , Capacidad Cardiovascular/fisiología , Femenino , Estado de Salud , Humanos , Masculino , Pruebas de Función Respiratoria , España , Dispositivos Electrónicos VestiblesRESUMEN
This work presents the first tests performed with radiochromic films and a new MicroâOptoâElectro-Mechanical system (MOEMS) for in situ dosimetry evaluation in radiotherapy in real time. We present a new device and methodology that overcomes the traditional limitation of time-delay in radiochromic film analysis by turning a passive detector into an active sensor. The proposed system consists mainly of an optical sensor based on light emitting diodes and photodetectors controlled by both customized electronic circuit and graphical user interface, which enables optical measurements directly. We show the first trials performed in a lowâenergy proton cyclotron with this MOEMS by using gafchromic EBT3 films. Results show the feasibility of using this system for in situ dose evaluations. Further adaptation is ongoing to develop a full realâtime active detector by integrating MOEM multiâarrays and films in flexible printed circuits. Hence, we point to improve the clinical application of radiochromic films with the aim to optimize radiotherapy treatment verifications.
RESUMEN
Frequently, stranded sea turtles require rehabilitation under controlled conditions. Currently, few publications have described the conditions under which rehabilitation is to take place, particularly with respect to the hatchling life stage. To address this paucity of data, we conducted some experiments to assist rehabilitating facilities assess their handling of hatchlings. While in captivity, hatchlings are routinely handled, for example, for data collection and cleaning. Standardization of handling and housing protocols is necessary to define the most adequate rearing conditions to maintain hatchling welfare. Accordingly, the aim of this study was to assess plasma circulating corticosterone (Cort) concentration and growth, as a biomarker for the stress of hatchling loggerhead sea turtles (Caretta caretta) under controlled conditions. We performed two experiments to analyze handling frequency and stocking density. In both, Cort was measured and correlated with variations in animal weight and length. In handling experiments, Cort exhibited no significant increase when hatchlings were handled once a week, whereas Cort was significantly elevated when hatchlings were handled once every 2 weeks, suggesting that hatchlings have the ability to acclimate to frequent handling. However, hatchlings exhibited similar growth and mortality, regardless of handling regime. In stocking density experiments, hatchling isolation induced a significant elevation of Cort, in comparison with hatchlings placed with conspecifics at increasing densities. Growth increased in singly housed hatchlings, while mortality increased in tanks with three or more hatchlings. The results obtained suggest that Cort, growth, and mortality should be measured to assess hatchling welfare when kept under controlled conditions.
Asunto(s)
Crianza de Animales Domésticos , Estrés Fisiológico/fisiología , Tortugas/fisiología , Animales , Corticosterona/sangre , Manejo Psicológico , Densidad de Población , Tortugas/sangreRESUMEN
PURPOSE: To study the agreement between proton microdosimetric distributions measured with a silicon-based cylindrical microdosimeter and a previously published analytical microdosimetric model based on Geant4-DNA in-water Monte Carlo simulations for low energy proton beams. METHODS AND MATERIAL: Distributions for lineal energy (y) are measured for four proton monoenergetic beams with nominal energies from 2.0 MeV to 4.5 MeV, with a tissue equivalent proportional counter (TEPC) and a silicon-based microdosimeter. The actual energy for protons traversing the silicon-based microdosimeter is simulated with SRIM. Monoenergetic beams with these energies are simulated with Geant4-DNA code by simulating a water cylinder site of dimensions equal to those of the microdosimeter. The microdosimeter response is calibrated by using the distribution peaks obtained from the TEPC. Analytical calculations for y ¯ F and y ¯ D using our methodology based on spherical sites are also performed choosing the equivalent sphere to be checked against experimental results. RESULTS: Distributions for y at silicon are converted into tissue equivalent and compared to the Geant4-DNA simulated, yielding maximum deviations of 1.03% for y ¯ F and 1.17% for y ¯ D . Our analytical method generates maximum deviations of 1.29% and 3.33%, respectively, with respect to experimental results. CONCLUSION: Simulations in Geant4-DNA with ideal cylindrical sites in liquid water produce similar results to the measurements in an actual silicon-based cylindrical microdosimeter properly calibrated. The found agreement suggests the possibility to experimentally verify the calculated clinical y ¯ D with our analytical method.
RESUMEN
Microdosimetry has been traditionally performed through gaseous proportional counters, although in recent years different solid-state microdosimeters have been proposed and constructed for this task. In this paper, we analyze the response of solid-state devices of micrometric size with no intrinsic gain developed by CNM-CSIC (Spain). There are two major aspects of the operation of these devices that affect the reconstruction of the probability distributions and momenta of stochastic quantities related to microdosimetry. For micrometric volumes, the drift and diffusion of the charge carriers gives rise to a partial charge collection efficiency in the peripheral region of the depleted volume. This effect produces a perturbation of the reconstructed pulse height (i.e. imparted energy) distributions with respect to the actual microdosimetric distributions. The relevance of this deviation depends on the size, geometry and operating conditions of the device. On the other hand, the electronic noise from the single-event readout set-up poses a limit on the minimum detectable lineal energy when the microdosimeter size is reduced. This article addresses these issues to provide a framework on the physical constraints for the design and operation of solid-state microdosimeters.
Asunto(s)
Equipos y Suministros Eléctricos , Radiometría/instrumentación , ProbabilidadRESUMEN
The importance of plant-microbe interactions to the success of invasive plants has rarely been studied at a global scale. Carpobrotus edulis (L.) N. E. Br is an aggressive invader in many areas around the world, forming dense mats in coastal environments. In an approach at a large geographical scale, over a wide latitudinal and climatic range, we tested the ability of C. edulis to alter the local bacterial and fungal community structure and microbial activity in eight invaded coastal locations. The factors invasiveness and geographical location had a significant effect on the soil microbiota, the microbial community composition and structure from the rhizosphere of native and C. edulis plants being distinct in every location. The effect of the invader on all the chemical, physico-chemical, and microbiological properties studied depended on the invaded location. The soil bacterial and fungal community composition and structure were related to the soil available nutrients and mean annual rainfall, and those of the soil bacterial community were also linked to the soil respiration and latitude. Overall, our results reveal that the ability of the invader C. edulis to alter soil microbial community structure harboring a specific microbiome was widespread across a large invaded range - leading to concurring changes in the rhizosphere microbial functioning, such as nutrient cycling.
Asunto(s)
Microbiota , Rizosfera , Especies Introducidas , Suelo , Microbiología del SueloRESUMEN
Particle therapy is a therapy technique that exploits protons or light ions to irradiate tumor targets with high accuracy. Protons and 12C ions are already used for irradiation in clinical routine, while new ions like 4He and 16O are currently being considered. Despite the indisputable physical and biological advantages of such ion beams, the planning of charged particle therapy treatments is challenged by range uncertainties, i.e. the uncertainty on the position of the maximal dose release (Bragg Peak - BP), during the treatment. To ensure correct 'in-treatment' dose deposition, range monitoring techniques, currently missing in light ion treatment techniques, are eagerly needed. The results presented in this manuscript indicate that charged secondary particles, mainly protons, produced by an 16O beam during target irradiation can be considered as candidates for 16O beam range monitoring. Hereafter, we report on the first yield measurements of protons, deuterons and tritons produced in the interaction of an 16O beam impinging on a PMMA target, as a function of detected energy and particle production position. Charged particles were detected at 90° and 60° with respect to incoming beam direction, and homogeneous and heterogeneous PMMA targets were used to probe the sensitivity of the technique to target inhomogeneities. The reported secondary particle yields provide essential information needed to assess the accuracy and resolution achievable in clinical conditions by range monitoring techniques based on secondary charged radiation.