Cardiorespiratory effects of enoximone in anaesthetised colic horses

Reasons for performing study: No studies have been reported on the effects of enoximone in anaesthetised colic horses. Objective: To examine whether enoximone improves cardiovascular function and reduces dobutamine requirement in anaesthetised colic horses. Methods: Forty‐eight mature colic horses were enrolled in this prospective, randomised clinical trial. After sedation (xylazine 0.7 mg/kg bwt) and induction (midazolam 0.06 mg/kg bwt, ketamine 2.2 mg/kg bwt), anaesthesia was maintained with isoflurane in oxygen and a lidocaine constant rate infusion (1.5 mg/kg bwt, 2 mg/kg/h). Horses were ventilated (PaCO₂<8.00 kPa). If hypotension occurred, dobutamine and/or colloids were administered. Ten minutes after skin incision, horses randomly received an i.v. bolus of enoximone (0.5 mg/kg bwt) or saline. Monitoring included respiratory and arterial blood gases, heart rate (HR), arterial pressure and cardiac index (CI). Systemic vascular resistance (SVR), stroke index (SI) and oxygen delivery index (DO₂I) were calculated. For each variable, changes between baseline and T10 within each treatment group and/or colic type (small intestines, large intestines or mixed) were analysed and compared between treatments in a fixed effects model. Differences between treatments until T30 were investigated using a mixed model (α= 0.05). Results: Ten minutes after enoximone treatment, CI (P = 0.0010), HR (P = 0.0033) and DO₂I (P = 0.0007) were higher and SVR lower (P = 0.0043) than at baseline. The changes in CI, HR and SVR were significantly different from those after saline treatment. During the first 30 min after enoximone treatment, DO₂I (P = 0.0224) and HR (P = 0.0003) were higher than after saline administration. Because the difference in HR between treatments was much clearer in large intestine colic cases, an interaction was detected between treatment and colic type in both analyses (P = 0.0076 and 0.0038, respectively). Conclusions: Enoximone produced significant, but short lasting, cardiovascular effects in colic horses. Potential relevance: Enoximone's cardiovascular effects in colic horses were of shorter duration than in healthy ponies.     

Real-time image processing for crop/weed discrimination in maize fields

This paper presents a computer vision system that successfully discriminates between weed patches and crop rows under uncontrolled lighting in real-time. The system consists of two independent subsystems, a fast image processing delivering results in real-time (Fast Image Processing, FIP), and a slower and more accurate processing (Robust Crop Row Detection, RCRD) that is used to correct the first subsystem’s mistakes. This combination produces a system that achieves very good results under a wide variety of conditions. Tested on several maize videos taken of different fields and during different years, the system successfully detects an average of 95% of weeds and 80% of crops under different illumination, soil humidity and weed/crop growth conditions. Moreover, the system has been shown to produce acceptable results even under very difficult conditions, such as in the presence of dramatic sowing errors or abrupt camera movements. The computer vision system has been developed for integration into a treatment system because the ideal setup for any weed sprayer system would include a tool that could provide information on the weeds and crops present at each point in real-time, while the tractor mounting the spraying bar is moving.     

Rapid determination of crocetin esters and picrocrocin from saffron spice (Crocus sativus L.) using UV-visible spectrophotometry for quality control

The aim of this work was the development of multivariate models able to determine the content of the main crocetin esters and picrocrocin from spectrophotometric data that could be used for routine quality control of saffron. These compounds were determined with HPLC in Spanish saffron, and their absorbance spectra from 190 to 700 nm were simultaneously monitored. Partial least-squares regression (PLSR) models have been obtained and applied to the determination of individual crocetin esters, to the sum of crocetin esters, and to picrocrocin. A modification of the Kennard-Stone algorithm was used to divide the pool of samples into calibration and validation subsets. The best predictions were obtained with the sum of crocetin esters model, followed by the model for cis-crocetin (beta- D-glucosyl)-(beta- D-gentiobiosyl) ester, trans-crocetin di-(beta- D-gentiobiosyl) ester, and trans-crocetin (beta- D-glucosyl)-(beta- D-gentiobiosyl) ester, whereas the worst predictions were found with the picrocrocin and trans-crocetin (beta- D-gentiobiosyl) ester models. These models may enhance quality control in saffron enterprises.     

Effects of thinning intensity on radial growth patterns and temperature sensitivity in <Emphasis Type="Italic">Pinus canariensis</Emphasis> afforestations on Tenerife Island,Spain

• Context   

The suitability of thinning to prevent forest growth decline as a result of global warming has not been tested extensively in Macaronesian Canary pine (Pinus canariensis Sweet ex Spreng.).     

Afforestation method affects the isotopic composition of planted Pinus halepensis in a semiarid region of Spain

We used an isotopic approach to evaluate the effects of three afforestation methods on the ecophysiology of an Aleppo pine plantation in semiarid Spain. The site preparation methods tested were excavation of planting holes (H), subsoiling (S), and subsoiling with addition of urban solid refuse to soil (S + USR). Five years after plantation establishment, trees in the S + USR treatment were over three times larger than those in the S treatment, and nearly five-fold larger than those planted in holes. Differences in tree biomass per hectare were even greater due to disparities in initial planting density and pine tree mortality among treatments. Pine trees in the S + USR treatment showed higher foliar P concentration, δ¹³C and δ¹⁵N than those in the S or H treatments. Foliar δ¹⁵N data proved that trees in the S + USR treatment utilized USR as a source of nitrogen. Foliar δ¹³C and δ¹⁸O data suggest that improved nutrient status differentially stimulated photosynthesis over stomatal conductance in the pine trees of the S + USR treatment, thus enhancing water use efficiency and growth. In the spring of 2002, trees in the S + USR treatment exhibited the most negative predawn water potentials of all the treatments, indicating that the rapid early growth induced by USR accelerated the onset of intense intra-specific competition for water. The results of this study have implications for the establishment and management of Aleppo pine plantations on semiarid soils. Planting seedlings at low density and/or early thinning of pine stands are strongly recommended if fast tree growth is to be maintained beyond the first few years after USR addition to soil. Foliar C, O and N isotope measurements can provide much insight into how resource acquisition by trees is affected by afforestation techniques in pine plantations under dry climatic conditions.     

Solventless Microextraction Techniques for Determination of Trihalomethanes by Gas Chromatography in Drinking Water

Three different solventless sample preparation techniques based on microextraction, membrane extraction, and headspace extraction have been developed and optimized for determination of trihalomethanes in drinking water by gas chromatography electron capture detector and mass spectrometry detection. The techniques employed were headspace (HS) solid-phase microextraction, hollow fiber liquid-phase microextraction (HFLPME) and HS extraction. All techniques used were optimized with different experimental designs in order to select the most relevant variables which significantly affect the different processes. The different analytical figures of merit such as limit of detection (LOD), limit of quantification, reproducibility, accuracy, and linear dynamic range were obtained. The new HFLPME method applied used a hollow fiber membrane of polypropylene and the optimized variables were extraction time, extraction temperature, and salting-out effect. The software MODDE 6.0 was used and its design was one central composite on face with a total of 17 runs. The best conditions for the HFLPME were 20 min, 40°C, and 10% NaCl, respectively. The LODs ranged from 0.018 μg·L⁻¹ (for CHClBr₂) to 0.049 μg·L⁻¹ (for CHBr₃), being this technique the most sensitive one among those studied. Finally, after having optimized the sample preparation techniques and chromatographic conditions, several water samples were taken in two different water treatment plants in Spain (Zaragoza) and Colombia (Viterbo, Caldas). The results obtained are shown and discussed.     

Dry matter content during extension of twigs,buds and leaves reflects hydraulic status related to earlywood vessel development in <Emphasis Type="Italic">Quercus pyrenaica</Emphasis> Willd.

A quantitative method was tested to describe crown phenophases in relation to water content and to secondary growth in ring-porous species, based on the hypothesis that new shoots require hydrated tissues to maintain the necessary turgor for extension, leading to a reduction in dry matter content (DMC). We collected a three-year-old branch from 11 Quercus pyrenaica Willd. trees at 10-day intervals to estimate DMC of newly developing buds, leaves, and twigs, and processed two opposite stem microcores for xylogenesis. Branch phenophases and shoot length were recorded in the field. The DMC of all organs decreased during crown development, with a minimum in early June, followed by a gradual increase up to initial values in late September. The shoot extension period concurred with the lowest DMC, but also with the beginning of earlywood maturation in the main stem, suggesting a high tissue hydration only when earlywood vessels become functional to fulfill enough water requirements for shoot and leaf extension. These results confirm the usefulness of DMC to accurately quantify the phenology of primary growth from bud swelling up to full leaf extension, as a complement to qualitative methods. This variation in DMC appears to be linked to secondary growth as a result of earlywood vessel development.     

Visual quality: An examination of a South American Mediterranean landscape,Andean foothills east of Santiago (Chile)

This study assessed landscape visual quality in a sector of Andean foothills, east of Santiago, Chile. Sample photographs were taken in four dominant native landscape types that were systematically selected on the basis of four categories of vegetation density. Visitors (n = 180) were randomly sampled from among the residents of Santiago. The results showed that native vegetation has a positive impact on visual quality. Sclerophyllous shrublands and ravines (associated with semi-arid forests) are rated higher than savannahs of “espinales” and shrublands with succulent plants (associated with semi-arid grassland with shrubs). Findings also indicate that landscape scenes with high-vegetation density have a positive effect on visual quality, while those with a low density have a negative one. The key is the amount of visual access, which also increases people's perceptions of safety and orientation. Finally, results showed that information variables are associated with people's visual appreciation. Two preference factors were found to be consistent with the model of spatial information of Kaplan and Kaplan (1989). The implications of the results for the enhancement of public consensus in the planning and management of the Andean foothills, east of Santiago, are also discussed.