RESUMEN
Air-water diffusive carbon fluxes (e.g., CO2 and CH4) in reservoirs, particularly those dammed in river valleys, are the major pathway of reservoir carbon emissions. Hydrodynamic conditions caused by real-time reservoir operation could potentially affect air-water transfer of these greenhouse gases (GHGs), yet still under explored. Here, we proposed an estimation method of gross carbon emissions based on a computational fluid dynamic (CFD) modelling approach. The model assumed that air-water mass transfer was primarily regulated by surface turbulence, and disregarded contributions from biogeochemical processes as well as seasonality of meteorological parameters (i.e., wind speed and direction; air temperature). Through the hydrodynamic modeling, reservoir water level, flow velocity, surface turbulence, and air-water transfer velocity of carbon fluxes were elaborated. Gross carbon emissions were integrated by the carbon fluxes in each discrete cell and time under real-time reservoir operation. The Xiangjiaba Reservoir (XJB), located in the upper Yangtze Basin, was selected as the case of the study. Based on daily hydrological data in 2018, such as reservoir inflow, outflow and water level, the gross CO2 and CH4 emissions in the reservoir were approximately 6.7 Gg and 5.6 Mg. Variations of daily water level and discharge induced by reservoir operation could evidently affect carbon emissions. In particular, when reservoir initiated its impoundment, the discharge could be the probably critical factor that affected mass transfer velocity and carbon emissions in the reservoir. Our model could provide a new vision for evaluating the effect of real-time reservoir operation on carbon emissions.
Asunto(s)
Dióxido de Carbono , Agua , Carbono , Hidrodinámica , Estaciones del Año , Metano/análisis , Monitoreo del AmbienteRESUMEN
With the growing development of hydropower projects all over the world, the excessive greenhouse gas (GHG) emissions from increasing reservoirs have drawn public concern. While precise evaluations of GHG emissions are urgently needed, the widely applied methods including floating chamber (FC) method and thin boundary layer (TBL) method are unsatisfactory. In this paper, a new methodology of estimating CO2 emission coupling FC and TBL methods was proposed. Three efforts were achieved stepwise:1) the CO2 transfer coefficient was determined combining the measurements of FC method and TBL model; 2) a semi-empirical model connecting gas-water transfer coefficient and near-surface water turbulence in reservoir was proposed; 3) finally, since surface turbulence in the reservoir could be describe in detail by numerical simulation, integration thousands of discrete cells of local fluxes could be applied to estimate the total CO2 emission with an improved precision. Nine locations in Xiangjiaba Reservoir were selected as a demo study for applying the method, the CO2 emission in the whole reservoir was about 1.37 kg/s. With a deeper insight into the law of gas transfer and an elaborate consideration of the whole reservoir, this study is expected to provide a new approach and technical support to estimate the CO2 emissions accurately in reservoirs.
Asunto(s)
Dióxido de Carbono , Gases de Efecto Invernadero , Dióxido de Carbono/análisis , Monitoreo del Ambiente , Gases de Efecto Invernadero/análisis , Metano/análisis , AguaRESUMEN
Hydropower, which utilizes energy from fast-moving water, can help alleviate the energy crisis and promote economic development. For safety and ecological purposes, dams must discharge periodically. This discharge process, which occurs with the supersaturation of total dissolved gas (TDG), affects the fish and other aquatic organisms living in downstream river areas. Previous studies have shown that the supersaturated TDG dissipation process is closely related to hydraulic properties such as the flow rate, water depth and turbulent kinetic energy. Additionally, the presence of solid walls such as vegetation leaves in water can adsorb dissolved gases in water, thereby promoting the supersaturated TDG dissipation process, and the adsorption effect is closely related to the solid wall material. However, systematic studies on how solid walls in water can quickly absorb dissolved gases from water and rapidly reduce the TDG saturation of water are lacking. Herein, a series of experiments was conducted to study the dissipation process of supersaturated TDG under the action of solid walls in water and to reveal the adsorption effect of solid wall surface properties on dissolved gas. The results showed that the surface roughness and hydrophobicity (contact angle) are the key factors related to the adsorption effect of solid walls on the TDG in water. Generally, the dissipation rate of supersaturated TDG first increased and then decreased with increasing surface roughness. The supersaturated TDG dissipation rate increased monotonically with increasing contact angle. Based on the experimental data, the adsorption coefficient, which represents the adsorption effect of the solid wall for dissolved gas in water, was proposed, and a prediction formula between the adsorption coefficient and the contact angle of the solid wall was established. These results can provide theoretical support for the utilization of the solid wall adsorption effect to mitigate the adverse effects of supersaturated TDG and protect fish.
Asunto(s)
Gases , Movimientos del Agua , Adsorción , Animales , Peces , RíosRESUMEN
This investigation evaluated the distributions of airborne adenovirus and Mycoplasma pneumoniae in public areas in the pediatric department of Children's Hospital in northern Taiwan. The airborne viral and bacterial concentrations were evaluated twice a week for a year using filter sampling with an airflow rate of 12 liters per minute for eight hours in the pediatric outpatient department and 24 hours in the pediatric emergency room. Real-time polymerase chain reaction assays were conducted for analysis. Approximately 18% of the air samples from the pediatric emergency room were found to contain adenovirus. Approximately forty-six percent of the air samples from the pediatric outpatient department contained Mycoplasma pneumoniae DNA products. High detection rates of airborne adenovirus DNA were obtained in July and August in the pediatric public areas. Airborne Mycoplasma pneumoniae was detected only in July in the pediatric emergency room and the peak levels were found from August to January in the pediatric outpatient department. Airborne particles that contained adenovirus and Mycoplasma pneumoniae were the most prevalent in the pediatric public areas. The potential relationship between these airborne viral/bacterial particles and human infection should be examined further.
Asunto(s)
Infecciones por Adenoviridae/diagnóstico , Adenoviridae/aislamiento & purificación , Microbiología del Aire , Mycoplasma pneumoniae/aislamiento & purificación , Neumonía por Mycoplasma/diagnóstico , Adenoviridae/genética , Infecciones por Adenoviridae/virología , ADN Bacteriano/análisis , ADN Viral/análisis , Servicio de Urgencia en Hospital , Hospitales Pediátricos , Humanos , Mycoplasma pneumoniae/genética , Neumonía por Mycoplasma/microbiología , Estaciones del AñoRESUMEN
OBJECTIVE: Given the increased popularity of complementary and alternative medicine (CAM) and traditional Chinese medicine (TCM), this study aimed to evaluate the effects of interactive media on self-directed learning in patients' knowledge of diabetes and related CAM/TCM strategies, the ability to control blood sugar levels, and self-care in people with diabetes. DESIGN: An experimental study design was used. The experimental group received patient education through interactive multimedia about diabetes for 3 months, while the control group received a routine 3-month patient education. SAMPLE: On completion, 60 subjects from Taiwan were evaluated-30 in an experimental group and 30 in a control group. MEASUREMENTS: Data were collected from both groups at baseline and at the completion of the patient education. The findings were then compared to evaluate the effects of the intervention on the subjects' knowledge of diabetes, blood sugar control, and self-care. RESULTS: The experimental group showed greater improvement in understanding diabetes than the control (t=3.29, p<.001). There was no significant difference in control of blood sugar levels (t=-1.72, p=.10) and self-care (F=1.03, p=.32). CONCLUSIONS: The use of an interactive multimedia device to intervene in diabetes self-care was effective only in raising the subjects' knowledge about the disease. Additionally, the subjects may need more time to implement more effective blood sugar control and self-care activities after receiving instruction.
Asunto(s)
Instrucción por Computador/métodos , Diabetes Mellitus/prevención & control , Conocimientos, Actitudes y Práctica en Salud , Multimedia/estadística & datos numéricos , Educación del Paciente como Asunto/métodos , Autocuidado , Análisis de Varianza , Actitud Frente a la Salud , Distribución de Chi-Cuadrado , Curriculum , Diabetes Mellitus/metabolismo , Evaluación Educacional , Femenino , Hemoglobina Glucada/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Investigación en Educación de Enfermería , Folletos , Autocuidado/métodos , Autocuidado/psicología , Encuestas y Cuestionarios , Taiwán , Interfaz Usuario-ComputadorRESUMEN
A new species of Kudoa lutjanus n. sp. (Myxosporea) is described from the brain and internal organs of cultured red snapper Lutjanus erythropterus from Taiwan. The fish, 260 to 390 g in weight, exhibited anorexia and poor appetite and swam in the surface water during outbreaks. Cumulative mortality was about 1% during a period of 3 wk. The red snapper exhibited numerous creamy-white pseudocysts, 0.003 to 0.65 cm (n = 100) in diameter, in the eye, swim bladder, muscle and other internal organs, but especially in the brain. The number of pseudocysts per infected fish was not correlated with fish size or condition. Mature spores were quadrate in apical view and suboval in side view, measuring 8.2 +/- 0.59 microm in width and 7.3 +/- 0.53 microm in length. The 4 valves were equal in size, each with 1 polar capsule. Polar capsules were pyriform in shape, measuring 3.62 +/- 0.49 microm in length and 2.2 +/- 0.49 microm in width. Mild inflammatory responses or liquefaction of host tissue were associated with K. lutjanus n. sp. infection. The junction of shell valves appeared as overlapping, straight lines. The polar filament formed 2 to 3 coils. A general PCR (polymerase chain reaction) primer for Kudoa amplified the small subunit (SSU) rDNA sequences, and the amplified gene was sequenced. It was evident from the phylogenetic tree that the 3 strains tested, AOD93020M, AOD93028M and AOD93028B, were identical and belonged to the Kudoa SS rRNA subgroup. The evolutionary tree showed that these strains form a unique clade, at a distance from other Kudoa species and myxosporeans. The spore's morphological and ultrastructural characteristics, as well as the SS rDNA properties of the isolates, were also essentially identical and served to distinguish them from representative Kudoa. It is, therefore, proposed that the strains isolated from the diseased red snapper be assigned to a new species.
Asunto(s)
Brotes de Enfermedades/veterinaria , Eucariontes/citología , Eucariontes/genética , Enfermedades de los Peces/epidemiología , Enfermedades de los Peces/patología , Enfermedades de los Peces/parasitología , Perciformes , Infecciones Protozoarias en Animales/patología , Animales , Secuencia de Bases , Encéfalo/parasitología , Cartilla de ADN , ADN Espaciador Ribosómico/genética , Microscopía Electrónica de Transmisión/veterinaria , Datos de Secuencia Molecular , Filogenia , Infecciones Protozoarias en Animales/epidemiología , Análisis de Secuencia de ADN/veterinaria , Especificidad de la Especie , Esporas Protozoarias/ultraestructura , Taiwán/epidemiología , Vísceras/parasitologíaRESUMEN
In May 2001, an epizootic yeast and bacterial co-infection in the giant freshwater prawn Macrobrachium rosenbergii occurred in Taiwan causing a cumulative mortality of 25%. The diseased prawns had a yellowish-brown body color, milky hemolymph, opaque, whitish muscles, and were approximately 7 mo old with total lengths ranging from 8 to 10 cm. Histopathological examination showed marked edema, yeast infiltration, and necrotic lesions with inflammation in the muscles, hepatopancreas and other internal organs. We isolated 2 pathogens from the diseased prawns, one was a yeast (AOD081MB) and the other a gram-positive coccus (AOD081EF). The gram-positive coccus was identified as Enterococcus faecium by the API 20 Strepsystem, conventional biochemical tests, and it had 99% 16S rDNA sequence identity (GenBank Accession Number AJ276355) to E. faecium (GenBank Accession Number AF529204). The sequence of a PCR product from the D1/D2 domain of 26S rDNA (GenBank Accession Number AF529297) from the yeast gave 99% sequence identity to Metschnikowia bicuspidata (GenBank Accession Number U44822). Experimental infections with these isolates produced gross signs and histopathological changes similar to those observed in the naturally infected prawns. The lethal doses (LD50) for isolate E. faecium AOD081EF, M. bicuspidata AOD081MB and the co-infection were 4.7 x 10(4), 2.6 x 10(2), and 2.4 x 10(2) colony-forming units prawn(-1), respectively. This is the first report of a confirmed co-infection of M. bicuspidata and E. faecium in prawn aquaculture.