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61.
Application of the agar gel technique in the diagnosis of infectious bovine rhinotracheitis 总被引:1,自引:0,他引:1
L A Estela 《American journal of veterinary research》1967,28(127):1903-1904
62.
Albiach-Martí MR Guerri J de Mendoza AH Laigret F Ballester-Olmos JF Moreno P 《Phytopathology》2000,90(2):134-138
ABSTRACT A total of 14 Spanish isolates of Citrus tristeza virus (CTV) and 1 isolate from Japan were transmitted by Aphis gossypii, and the subisolates obtained were compared with the source isolates for symptom expression and double-stranded RNA (dsRNA) pattern. Of the 14 Spanish isolates, 9 showed altered dsRNA patterns after aphid transmission but only minor variations in the intensity of symptoms induced on Mexican lime. Northern blot hybridization with complementary DNA (cDNA) probes corresponding to both the 5' and the 3' termini of the CTV genomic RNA (gRNA) showed that the dsRNA bands that could be used to discriminate between the dsRNA pattern of the source and the aphid-transmitted isolates were the replicative forms of defective RNAs (D-RNAs). Conversely, the Japanese isolate and two subisolates obtained from it by aphid transmission had the same dsRNA pattern, but one of the subisolates induced milder symptoms in several hosts. Dot-blot hybridization with cDNA probes representing several regions of the gRNA showed that most of the aphid-transmitted isolates differed from the corresponding source isolate by their hybridization pattern. Our results indicate that aphid transmission often sorts the populations of gRNA variants and D-RNAs present in CTV isolates. 相似文献
63.
Luis Arturo García Hernández Estela Martínez Borrego Hernán Salas Quintanal Aysen Tanyeri-Abur 《Agriculture and Human Values》2000,17(2):157-167
To explain globalization of the Mexicandairy production more precisely, globalization indairy systems worldwide and within Mexico ispresented, using an intensive dairy operation in theregion of La Laguna (North Mexico), and a traditionaldairy operation in Los Altos de Jalisco (West Mexico)as examples. The focus is on the economic aspects ofregionalization, and how it relates to theglobalization process. In this context, the process ofregionalization of the North American dairy systemsand their relationships with the local systems in LaLaguna and Los Altos de Jalisco are presented. Themain thesis in this paper is whether globalization hasacted as a factor to help homogenize the dairy systemsin terms of economic, political, and culturalprocesses affected by world tendencies as well aslocal trends. 相似文献
64.
Nicolás Vidal Franco Teixeira de Mello Iván González-Bergonzoni Anahí López-Rodríguez Giancarlo Tesitore Joaquín Pais Samanta Stebniki Ivana Silva Alejandro D’Anatro 《Ecology of Freshwater Fish》2020,29(2):334-345
Unravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temperate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence of temperature and river discharge as triggers of Iheringichthys labrosus’ reproduction. We studied the following reproductive variables: gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (K). Females of I. labrosus were examined in a time series of ten years along three sites located in Lower Uruguay River at the beginning (last week of November-first week of December, spring) and by the end of the reproductive period (middle-end of April, autumn). Generalised linear models detected a positive effect of mean winter temperature and site on the spring mature female GSI. Site was significant in addition to the interaction between temperature and site. Moreover, the effect of winter temperature was stronger than water discharge in triggering reproductive timing of I. labrosus, contrary to the model proposed for other species in tropical systems. Additionally, a literature review suggested a latitudinal gradient on reproduction, occurring earlier and prolonged with decreasing latitude (and increasing temperature). In this study, we stated the effect of temperature on the life history in a Neotropical fish using a multifaceted approach, particularly important in the current context of global climate warming. 相似文献
65.
Jose Alfredo Gutierrez-Reyes ;Estela Flores-Velazquez ;Guillermo Agustin Reyes-Escalona ;Joaquin BraulioDelgadillo-Alvarez ;Marcela Amalia Mercado-Pezzat ;Eli Tonatiuh Selva-Hernandez ;Alejandro Perera-Ortiz ;Jose Alberto Ordufia-Sumaran ;Cecilia Romero-Torres ;Luis Antonio Jimenez-Zamudio ;Ethel AwildaGarcfa-Latorre Citlatepetl Salinas-Lara 《农业科学与技术》2014,(4):277-290
Mexico is considered by different international organizations as a country where the bovine tuberculosis is an endemic problem. However, there are important and consistent improvements in eradicating the disease by the implementation of government policies and with the livestock organization support. The current situation of the program shows good results regarding decreasing the prevalence, and as a consequence, the risk of this disease for public health and animal health, as well as the improvement in animal production and international and national trade. Today, the bovine tuberculosis distribution is almost known in Mexico. In addition, a series of controls and indicators have been established, which allow maintain consistency and reliability in the data that are managed and analyzed. 相似文献
66.
Maria Pilar Serrano‐Muela Estela Nadal‐Romero Noemí Lana‐Renault Jos Carlos Gonzlez‐Hidalgo Juan Ignacio Lpez‐Moreno Santiago Beguería Yasmina Sanjuan Jos María García‐Ruiz 《Land Degradation \u0026amp; Development》2015,26(3):249-262
An exceptional rainfall and hydrological event occurred on 19–21 October 2012 in the central western Pyrenees and was particularly significant in the Upper Aragón River basin and its tributaries, mainly the Irati River. Analysis of historical records showed that, considered separately, the event of 19 and 20 October ranked between the second and fifth highest most extreme daily precipitation events. For the two days combined (with a total between 200 and 260 mm), the precipitation event was the most extreme 2‐day event among all observation stations but one. The consequent flood destroyed part of an urban area, and a long stretch of a national road triggered landslides, enlarged the alluvial plain and caused generalised soil erosion in cultivated fields cropped with winter cereals. Badlands in the marls of the Inner Depression yielded high volumes of sediment. The floods in the tributaries were relatively moderate (return periods of 14–42 years), whereas in the Upper Aragón River, the flood corresponded to a return period of approximately 400–500 years and to 142 years at the end of the Yesa reservoir, although difficulties in estimating the discharge increased the uncertainty of these values. The Yesa and Itoiz reservoirs considerably reduced the intensity of the flood in the middle and lower Aragón River and confirmed the importance of the water level in the reservoirs when such rainfall events occur. The water storage in the Yesa reservoir increased from 16% to 53% as a consequence of the event. More integrated studies are necessary to decrease the risks associated with flood hazards. This is particularly the case in mountain areas, where the steep slopes and longitudinal gradients of the rivers shorten the concentration time of floods and increase the energy that erodes channels and riverbanks. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
67.
An automatic system based on the use of a PC-compatible computer was developed for the implementation of coulometric titrations by release of EDTA from its Hg complex on electrochemical reduction of the Hg2+ ion. A variety of indicators electrodes were assayed to obtain potentiometric titration curves. The method thus developed allows the straightforward, convenient determination of Ca and Mg and was applied to the analysis of various real samples with good results. 相似文献
68.
Fish that have escaped from a cormorant’s (Phalacrocorax carbo sinensis (L.)) grasp and/or which could not be swallowed due to their size suffer from various injuries resulting in consecutive infections
and subsequent increased mortality. Computer-assisted image analysis was applied to describe the extent of such injuries.
Two-year-old mirror carp, Cyprinus carpio L. (TL 200–300 mm, W 200–300 g) showed injuries ranging over approximately 10% of the total body surface. Immediately after wounding, the damaged
epithelium (scars) cover 5–35%, and deeper subdermal wounds caused by the beak tip pervading into muscle tissue cover an area
of 1–2% of the total body surface. On the side impacted by the cormorant’s lower mandible, extensive areas of epidermal contusions
(scars) occur. As time progresses, these ratios change—deeper necroses represent up to 10% of the total body surface and healing
epithelial scars comprise just 1–2%. In wounded silver carp, Hypophthalmichthys molitrix Val. (300–400 mm, W 500–700 g), the share of subdermal wounds usually does not exceed 0.5% due to their compact scaly cover. During pond draining
due to fish harvesting, the size spectrum of wounded fish increases and may also often include bigger fish (e.g., European
catfish, Silurus glanis L.) up to 2.2 kg. 相似文献
69.
Guadalupe Williams-Linera Claudia Alvarez-Aquino Estela Hernández-Ascención María Toledo 《New Forests》2011,42(2):131-148
Secondary successional vegetation represents one-third of the 7% of the original area covered with tropical dry forest that
remains in central Veracruz, Mexico. In this region, fallow periods are short, in general, no longer than 7–10 years, and
old secondary successional sites are not available. Therefore we evaluated the potential of very early successional stages
of tropical dry forest with different land use histories for recovering the structure and composition of regional forest.
We compared five early successional sites (7–72 months) with five nearby forest remnants. Successional sites had reached 38
and 30%, respectively, of the average basal area and density recorded for the forest understories, but only 5 and 10%, respectively,
of the basal area and density of forest overstories. A total of 132 tree species were recorded, 45 at successional and 107
at forest sites. Individuals of tree species with animal-dispersed seeds (57%) were significantly better represented than
wind-dispersed (22%) and self-dispersing (21%) species in both successional and forest sites. Successional sites had already
recruited 10% of the intermediate and shade-tolerant species that grow in forest remnants. However, only 20 species occurred
in both early successional and forest sites, several showing resprouting ability. We conclude that the entry of forest species
to the successional process at very early stages and the recruitment of individuals from resprouting may facilitate the recovery
of the dry forest in Veracruz. 相似文献
70.
Suárez Valles B Palacios García N Rodríguez Madrera R Picinelli Lobo A 《Journal of agricultural and food chemistry》2005,53(16):6408-6413
An analytical method for the determination of free amino acids in ciders is reported. It is based on high-performance liquid chromatography with an automatic precolumn derivatization with o-phthaldehyde and 3-mercaptopropionic acid and diode array detection. The method was applied to monitor the amino acids during second fermentation of sparkling ciders. This paper reports the influence of yeast strains and aging time on the amino acid composition of sparkling ciders. The application of principal component analysis enables the ciders to be differentiated on the basis of the two factors considered (yeast strain and aging time). The first principal component, which accounts for 58% of the total variance, achieved the separation according to aging time with serine, glycine, alanine, valine, ornithine, leucine, and lysine as the most important variables. The second principal component, accounting for 28% of the explained variance, is closely related to aspartic acid and asparagine and separates the samples according to the yeast strain. 相似文献