Theoretical Kinetics Study of the F(2P) + NH3 Hydrogen Abstraction Reaction

The hydrogen abstraction reaction of fluorine with ammonia represents a true chemical challenge because it is very fast, is followed by secondary abstraction reactions, which are also extremely fast, and presents an experimental/theoretical controversy about rate coefficients. Using a previously developed full-dimensional analytical potential energy surface, we found that the F + NH3 → HF + NH2 system is a barrierless reaction with intermediate complexes in the entry and exit channels. In order to understand the reactivity of the title reaction, thermal rate coefficidents were calculated using two approaches: ring polymer molecular dynamics and quasi-classical trajectory calculations, and these were compared with available experimental data for the common temperature range 276–327 K. The theoretical results obtained show behavior practically independent of temperature, reproducing Walther–Wagner’s experiment, but in contrast with Persky’s more recent experiment. However, quantitatively, our results are 1 order of magnitude larger than those of Walther–Wagner and reasonably agree with the Persky at the lowest temperature, questioning so Walther−Wagner’s older data. At present, the reason for this discrepancy is not clear, although we point out some possible reasons in the light of current theoretical calculationsThis work was partially supported by Gobierno de Extremadura, Spain, and FEDER (Project No. IB10001). Y.V.S. acknowledges the support of a Combustion Energy Research Fellowship through the Combustion Energy Frontier Research Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences under Award Number DE-SC0001198. A.F-.R. thanks Xunta de Galicia through Grant No. 2012/314 para a consolidación e a estruturación de unidades de investigación competitivas do Sistema Universitario de Galicia, 2012S

Biomass estimation of bluefin tuna in sea cages by the combined use of acoustic and optical techniques

In this paper, an experimental setup to estimate the biomass of caged bluefin tuna (Thunnus thynnus) in the Spanish Mediterranean coast is presented. Aims are to monitor individual tuna during all stages of growth, to control the transfer of fish caught in purse seines to towing cages and to be able to estimate the total number of specimens and the biomass transferred. To do this, we propose a combined system of acoustic and optical techniques (both non-intrusive), in order to obtain direct values of acoustical target strength (TS) and information on the orientation of tuna inside the acoustic beam and their size. To achieve complete information, ventral and dorsal acoustic measurements are done using in a first attempt a multiplexed scientific echosounder with two 200 KHz split-beam transducers, while a stereoscopic video system provides optical information and allows estimating the size and the weight of the specimens. Preliminary results indicate that thiscombined use of techniques provides precise information to determine the TS as a function of fish orientation and for proper monitoring of tuna in floating cages.Versión de editor

Using ultrasound for the monitoring and control of larval development of gilthead seabream (Sparus aurata) in tanks

In this work, we propose a non-invasive acoustic technique using ultrasound for the monitoring and control of larval development of gilthead seabream (Sparus aurata) in tanks. Biological measurements and target strength (TS) measurements have been carried out using a EK60 Simrad echosounder working at 200 kHz. The experiments have been carried out for three consecutive years in the marine aquaculture plant that Spanish Institute of Oceanography (IEO) has at Mazarron (Murcia, Spain). For the interpretation of the results, backscatter models were considered using the finite element method. The target strength values were evidenced with and without the presence of the developed swimbladder, showing a statistically significant relationship with the standard length, the area of the swimbladder and the percentage of larvae with a swimbladder

Experimental setup for monitoring the growth of tuna in cages by the combined use of acoustic and optical cages

Pre-prin

Ultrasonic monitoring of early larval development of fish in tanks. Case study: Gilthead seabream (Sparus aurata)

Swimbladder inflation is a significant matter in intensive fish farming, since it is related to larval survival rate and the morphological quality of individuals. In this work, we propose a non-invasive acoustic technique using ultrasound to monitor the swimbladder development of gilthead seabream (Sparus aurata) in tanks. The fundamental hypothesis is that, due to the high acoustic contrast of gas, the swimbladder’s inflation process can be detected by measuring the larvae’s target strength during their early development. Backscatter numerical models using the finite element method, developed from biological measurement data, were applied to evaluate the feasibility of the proposed method. The acoustic measurements were obtained using an EK60 Simrad echosounder working at 200 kHz. The target strength values were evidenced with and without the presence of a developed swimbladder, showing a statistically significant relationship with the swimbladder’s standard length, area and the percentage of larvae with a swimbladder. The experiments were carried out in the Spanish Institute of Oceanography (IEO)’s marine aquaculture plant at Mazarr´on (Murcia, Spain)

Environmental epigenomics: Current approaches to assess epigenetic effects of endocrine disrupting compounds (EDC's) on human health

Environmental Epigenomics is a developing field to study the epigenetic effect on human health from exposure to environmental factors. Endocrine disrupting chemicals have been detected primarily in pharmaceutical drugs, personal care products, food additives, and food containers. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with a high incidence and prevalence of many endocrine-related disorders in humans. Nevertheless, further evidence is needed to establish a correlation between exposure to EDC and human disorders. Conventional detection of EDCs is based on chemical structure and concentration sample analysis. However, substantial evidence has emerged, suggesting that cell exposure to EDCs leads to epigenetic changes, independently of its chemical structure with non-monotonic low-dose responses. Consequently, a paradigm shift in toxicology assessment of EDCs is proposed based on a comprehensive review of analytical techniques used to evaluate the epigenetic effects. Fundamental insights reported elsewhere are compared in order to establish DNA methylation analysis as a viable method for assessing endocrine disruptors beyond the conventional study approach of chemical structure and concentration analysis

Bluefin tuna (Thunnus thynnus) biomass estimation during transfers using acoustic and optic techniques

Our results show that the use of an acoustic transducer in transfers offers the possibility of performing an automatic counting with error below 10%, which is decreased to 1.2% after improving structure and algorithms. Moreover, the proposed procedure for automatic sizing using stereoscopic system achieved an accurate estimation of SFL distribution compared to true data from harvests, automatically measuring 20% of the fis

Automatic Bluefin Tuna (Thunnus thynnus) Biomass Estimation during Transfers Using Acoustic and Computer Vision Techniques

In this work, acoustic and computer vision techniques are combined to develop an automatic procedure for biomass estimation of tuna during transfers. A side scan sonar working at 200 kHz and a stereo camera, posi- tioned facing towards the surface to record the ventral aspect of fish, are set as acquisition equipment. Moreover, a floating structure has been devised to place the sensors between cages in transfers, creating a transfer canal that allows data acquisition while fish swim from donor to receiving cage. Biomass assessment is computed by counting transferred tuna and sizing a representative sample of the stock. The number of transferred tuna is automatically deduced from acoustic echograms by means of image processing techniques, whereas tuna size is computed from the stereo videos using our automatic computer vision procedure based on a deformable model of the fish ventral silhouette. The results show that the system achieves automatic tuna counting with error below 10%, achieving around 1% error in the best configuration, and automatic tuna sizing of more than 20% of the stock, with highly accurate Snout Fork Length estimation when compared to true data from harvests. These results fulfil the requirements imposed by International Commission for the Conservation of Atlantic Tunas for compliant transfer operations.Versión del editor1,42

Valoración de la presión intraocular con el tonómetro de rebote iCare ic100 en niños

La evaluación precisa de la presión intraocular (PIO) permite el diagnóstico oportuno del glaucoma infantil. El objetivo fue analizar la PIO medida con el tonómetro de rebote iCare ic100 en niños. Se realizó un estudio transversal en una muestra consecutiva de niños que asistieron a consulta de optometría. Fueron atendidos 100 pacientes, la edad promedio fue de 7,5±2,6 años y 55 % eran de sexo masculino. La medida se realizó con éxito en 97 % de los ojos. La PIO fue en promedio 13,8±3,5 mmHg para ojo derecho (OD) y 13,9±4,1 mmHg (OI) para ojo izquierdo (OI) (p=0,6411); en niñas fue de 13,8±3,1 mmHg [IC 95 % 12,8-14,7] en OD y de 13,6±3,0 mmHg [IC 95 % 12,7-14,5] en OI. La PIO en niños fue de 13,8±3,8 mmHg [IC 95 % 12,7-14,8] en OD y de 14,1±4,9 mmHg [IC 95 % 12,8-15,4] en OI. La PIO con el tonómetro de rebote resultó dentro de los valores de normalidad clínica en niños, sin diferencias significativas entre sexo o edad. Por la alta tasa de éxito en la medición, se propone la valoración de la PIO con el tonómetro ic100 en niños, para la identificación temprana de casos de glaucoma