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排序方式: 共有93条查询结果,搜索用时 15 毫秒
61.
Miguel Ángel Silva Salas Jaime Mondragón-Ancelmo María del Rosario Jiménez Badillo Gabriela Rodríguez Licea Fabio Napolitano 《Journal of dairy science》2021,104(5):6175-6184
We aimed to verify whether a low number of relevant animal-based indicators was able to discriminate 33 semi-intensive (grazing during the day and confinement during the night with access to an outdoor paddock; S-INT) and 8 intensive farms (permanent confinement with access to an outdoor paddock; INT) located in the Mexican semi-desert. In addition, we implemented the resource-based assessment scheme Animal Needs Index (ANI) with the identified animal-based indicators to compare the overall level of welfare in INT and S-INT. In particular, we used a protocol made up of 2 parts. The first comprised 4 evaluation sheets (locomotion, flooring, environment, management) and resource-based indicators derived from ANI, and the second one comprised a set of validated animal-based measures focusing on physical conditions and clinical signs of disease derived from the Animal Welfare Indicators scheme and reported in 2 additional sheets. The scoring system was also derived from ANI, with partial scores for each sheet to be summed to obtain the total score. A total of 1,116 dairy goats were assessed. All the observations and recordings were performed by an expert veterinarian evaluator assisted by an auxiliary, and longevity was retrieved from the farm records. The prevalence of animals displaying dirtiness, ocular discharge, abscesses, and claw overgrowth were higher in INT than in S-INT. Disbudding was routinely performed in INT only. Therefore, scurs, indicating improper disbudding, were recorded only in INT. In addition, the longevity of goats raised in S-INT was higher than in INT. Conversely, the prevalence of goats affected by anemia (i.e., FAMACHA scores >2) or lean (i.e., body condition score <2) tended to be higher in S-INT than in INT. No significant differences between the 2 groups of farms were detected for wounds, nasal discharge, integument alterations, fecal soiling, uterine prolapse, and subclinical mastitis. The results obtained using only animal-based measures were confirmed when resource-based variables were also included in the assessment, as 3 out of 6 sheets of the evaluation scheme (i.e., flooring, environment, and health—physical conditions) were scored higher in the S-INT than in the INT. As a consequence, the total score was also higher for S-INT than for INT. We conclude that the selected set of validated animal-based measures was able to discriminate between farms from different production systems. In particular, higher welfare levels were observed in S-INT farms, where the animals were allowed to spend most of the day on natural pasture, compared with INT farms, where the animals were constantly confined. Nevertheless, a certain degree of improvement should also be promoted in terms of anemia and body condition in S-INT farms. 相似文献
62.
C Javier Pérez Vera A Alvarez Iñaki Mondragón Analía Vázquez 《Polymer International》2007,56(5):686-693
The mechanical behavior of layered silicate/starch polycaprolactone blend nanocomposites was evaluated. Three different clays (Cloisite Na+, Cloisite 30B and Cloisite 10A) were used as reinforcement. Nanocomposites were prepared by melt intercalation followed by compression molding. These nanocomposites were characterized using X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis and tensile testing. X‐ray diffraction results showed that most of the clays were intercalated within the polymeric chains. In all cases, mechanical properties were improved with clay incorporation and the improvement was better as the clay content was increased. The best properties were achieved with Cloisite 10A due to their greatest compatibility with the matrix. A mechanical model, which takes into account the effective parameters of the clay, was used in order to estimate the dispersion of clay within the polymer. The highest dispersion was obtained for Cloisite 10A, which is in accordance with the experimental mechanical properties. Although dynamical‐mechanical properties improved with clay incorporation, the glass transition temperature was not affected. Copyright © 2006 Society of Chemical Industry 相似文献
63.
G Borges CJ Cherpitel ME Medina-Mora L Mondragón L Casanova 《Canadian Metallurgical Quarterly》1998,22(9):1986-1991
Our purpose was to obtain epidemiological measures of the association between habitual alcohol consumption, alcohol consumption before the event and alcohol abuse/dependence, and emergency room (ER) attendance compared to the general population in Pachuca-Hidalgo, a city located in the central area of Mexico. The study was a population based case-control design. Data consisted of breath samples to estimated blood alcohol concentration, as well as an interviewer-administered questionnaire, collected on a 24-hr basis, during the entire week, in each of the three main ERs of Pachuca. Cases were all patients who visited the three main hospitals ERs during the study period, classified according to their status as an injured or noninjured (medically ill) patient (n = 1511). The general population sample (n = 920) serves as a comparison group for both types of patients. Injured patients in the ER sample were significantly more likely to report high frequency/high quantity of drinking during the last 12 months than the general population [odds ratio and 95% confidence intervals = 5.55 (1.72-17.97)] and to report drinking within 6 hr before the injury. These relationships did not hold for noninjured patients. Both types of patients were more likely to report high frequency of drunkenness during the preceding 12 months, to be positive for alcohol dependence and to report drug use. We found in the city of Pachuca, a large relationship between habitual alcohol consumption and ER injuries. These findings support associations of alcohol consumption and admission to an emergency room found in ER and general population studies in other countries. Due to the increases in the risk found for abuse/dependent in both injured and noninjured patients, they both would benefit with a brief intervention strategy for reducing their alcohol consumption. 相似文献
64.
Escherichia coli DNA topoisomerase I is a well-studied type I DNA topoisomerase that catalyzes the breakage and rejoining of one DNA strand to allow passage of the other strand. We have cloned and over-expressed a 67 kDa amino-terminal fragment of the protein, and shown that it retains the ability of the intact enzyme to cleave single-stranded DNA. High-quality crystals of the purified 67 kDa fragment have been obtained. The crystals belong to space group P2(1)2(1)2(1), with cell dimensions a = 64.0 A, b = 79.9 A and c = 142.3 A. They diffract to at least 2.8 A at low temperature and, when cooled to cryogenic temperatures, to at least 1.9 A in a synchrotron source. A complete native data set and two derivative data sets have been collected. A multiple isomorphous replacement map to 3 A resolution shows clear secondary structural elements. Final structure determination is in progress. 相似文献
65.
66.
R Mondragón-Sánchez T Cortes-Espinoza R Sánchez-Cisneros H Parra-Silva H Hurtado-Andrade 《Canadian Metallurgical Quarterly》1994,41(6):585-588
An unusual case of amebic liver abscess that ruptured into the pericardial cavity is presented. This complication of amebic disease is extremely rare, and fatal. Chest X-ray and CT scan were performed for diagnosis. Pericardectomy with surgical drainage was performed; unfortunately, the patient died of massive pulmonary emboli. 相似文献
67.
68.
Saúl Sánchez‐Valdes Juan Méndez‐Nonell Francisco J Medellín‐Rodríguez Eduardo Ramírez‐Vargas Juan G Martínez‐Colunga Luis F Ramos de Valle Margarita Mondragón‐Chaparro Maria L López‐Quintanilla Maria L García‐Salazar 《Polymer International》2010,59(5):704-711
The compatibilization effects provided by different amine‐functionalized polyethylenes (PEs) versus those provided by a maleated polyethylene (PEgMA), for forming PE‐based film nanocomposites, were studied. Amine‐functionalized PEs were prepared by reaction of PEgMA with two primary amines, 2‐aminoethanol (EA) and 1,12‐aminododecane (D12), and a tertiary amine, 2‐[2‐(dimethylamino)ethoxy]ethanol (DMAE), in the melt to form the corresponding PEgEA, PEgD12 and PEgDMAE. Nanocomposites were prepared by melt mixing in a twin‐screw extruder PE and these three functionalized compatibilizers with a modified montmorillonite clay. The purpose of the current work was to determine the effect of the various amine‐functionalized PEs on the degree of exfoliation and optical properties of PE–clay nanocomposites in order to obtain nanocomposite films for greenhouse cover applications. Fourier transform infrared analysis confirmed the formation of the amine‐modified PE compatibilizers. Structural, morphological, mechanical, rheological and optical properties of film samples were used to characterize the nanocomposites. All the amine‐modified PE‐compatibilized nanocomposites had better clay exfoliation compared to uncompatibilized PE composites. Results showed that PEgDMAE formed highly exfoliated morphology and a favorable balance between mechanical (stiffness and ductility), optical and thermal insulating film properties even at higher clay contents. It was determined that nanocomposites with greater exfoliated structure showed better optical and thermal insulating film properties. PEgEA and PEgD12 compatibilizers did not provide a better interaction for exfoliation of the organoclay than the PEgMA material. The PEgDMAE compatibilizer led to a highly exfoliated morphology and a favorable balance between mechanical, optical and thermal insulating film properties even at higher clay contents. The PEgDMAE film nanocomposites could be used ideally for greenhouse cover applications. Copyright © 2010 Society of Chemical Industry 相似文献
69.
Iván F. Mondragón Miguel A. Olivares-Méndez Pascual Campoy Carol Martínez Luís Mejias 《Autonomous Robots》2010,29(1):17-34
This paper presents an implementation of an aircraft pose and motion estimator using visual systems as the principal sensor
for controlling an Unmanned Aerial Vehicle (UAV) or as a redundant system for an Inertial Measure Unit (IMU) and gyros sensors.
First, we explore the applications of the unified theory for central catadioptric cameras for attitude and heading estimation,
explaining how the skyline is projected on the catadioptric image and how it is segmented and used to calculate the UAV’s
attitude. Then we use appearance images to obtain a visual compass, and we calculate the relative rotation and heading of
the aerial vehicle. Additionally, we show the use of a stereo system to calculate the aircraft height and to measure the UAV’s
motion. Finally, we present a visual tracking system based on Fuzzy controllers working in both a UAV and a camera pan and
tilt platform. Every part is tested using the UAV COLIBRI platform to validate the different approaches, which include comparison
of the estimated data with the inertial values measured onboard the helicopter platform and the validation of the tracking
schemes on real flights. 相似文献
70.
G. C. Mondragón Rodríguez B. Saruhan O. Petrova W. Grünert 《Topics in Catalysis》2009,52(13-20):1723-1727
Perovskite based Pd catalysts were prepared by a modified citrate route and analyzed with SEM, XRD, TEM and XPS techniques regarding the state of palladium. Integration of Pd into the perovskite lattice was compared with impregnation onto the support. Clear indications of Pd-substitution in the La-based perovskites were found by XPS and SEM. The integrated Pd-ions diffuse out of the perovskite lattice under reductive conditions forming metallic palladium nano-particles (less than 15 nm size) while the Pd particles obtained via the impregnation route were in the order of 80 nm. In the selective catalytic reduction of NO by propene, up to 35% NO conversion at 250 °C were obtained at a very low W/F of 0.015 g s mL?1, with decreasing tendency at increasing oxygen content. Differences between impregnated and Pd-integrated catalysts were obvious only at high O2 content (5 vol.%) where the Pd-integrated catalyst exhibited a lower tendency to oxidize the propene reductant. 相似文献