Chemical and biological characteristics of alkaline saline soils from the former Lake Texcoco as affected by artificial drainage   总被引：3，自引：0，他引：3  

M. L. Luna-Guido  R. I. Beltrán-Hernández  N.A. Solís-Ceballos  N. Hernández-Chávez  F. Mercado-García  J. A. Catt  V. Olalde-Portugal  L. Dendooven 《Biology and Fertility of Soils》2000,32(2):102-108

 Soils from the former Lake Texcoco are alkaline saline and were artificially drained and irrigated with sewage effluents since the late 1980s. Undrained soil and soil drained for 1, 5 and 8 years were sampled, characterized and incubated aerobically for 90 days at 22±1  °C while production of CO₂, available P and concentrations of NH₄ ⁺, NO₂ ^– and NO₃ ^– were monitored. Artificial drainage decreased pH_H2O, water holding capacity, organic C, total N, and Na⁺, K⁺, Mg²⁺, B, Cl^– and SO₄ ^2– concentrations, increased inorganic C and Ca²⁺ concentrations more than 5-fold while total P was not affected. Microbial biomass C decreased with increased length of drainage but bacteria, actinomycetes, denitrifiers and cellulose-utilizing bacteria tended to show opposite trends. CO₂ production was less in soils drained ≥5 years compared to undrained soil but more than in soils drained for 1 year. Emission of NH₃ was negligible and concentrations of NH₄ ⁺ remained constant over time in each soil. Nitrification, as witnessed by increases in NO₃ ^– concentrations, occurred in soil drained for 8 years. NO₂ ^– concentrations decreased in soils drained ≤1 year in the first 7 days of the incubation and remained constant thereafter. It was found that artificial drainage of soils from the former Lake Texcoco profoundly affected soil characteristics. Decreases in pH and Na⁺, K⁺, Cl^– and SO₄ ^2– concentrations made conditions more favourable for plant growth, although low concentrations of inorganic N and available P might be limiting factors. Received: 1 December 1999  相似文献   

Effect of purification method on the electrical properties of the carbon nanotube fibers     

Chan Sol Kang  Il Jae Lee  Moo Song Seo  Sun Hong Kim  Doo Hyun Baik 《Fibers and Polymers》2017,18(8):1580-1585

We purified as-received CNT fibers (CNTFs) with four different methods and systematically examined effects of various purifications on the morphology, structure, and electrical conductivity of the resultant CNTFs, respectively. The purified CNTFs were characterized by an optical microscope, transmission electron microscope (TEM) coupled with an energy dispersive X-ray spectrometer (EDS), Raman spectroscopy, and multiple source meters. Optical images showed that morphology of CNTFs did not largely change after purification. TEM images and EDS results showed that the Fe impurities, 21.9 wt%, in CNTFs were decreased to 0.17-1.20 wt% and were nearly eliminated by acid and alkali purifications, respectively. Raman results identified the I_D/I_G ratio of CNTFs was 0.71, while those of HCl treatment after steam with heat (HSCNTFs-HCl), NaOCl treatment after steam with heat (HSCNTFs-NaOCl), and NaOH treatment with heat without steam (NaOH-HCNTFs) were 0.45, 0.49, and 0.57, respectively, which means that purification methods of CNTFs performed in this study are thought to be satisfactory for manufacturing high-purity CNTFs. Electrical conductivity (1.4×10⁴ S/m) of NaOH-HCNTFs (one-step procedure) was twice as high as that (7.3×10³ S/m) of CNTFs, but lower than those (2.1-2.3×10⁴ S/m) of HSCNTFs-HCl and HSCNTFs-NaOCl (two-step processes), which demonstrates that two-step processes rather than one-step procedure would have a positive effect on the electrical conductivity of the resultant CNTFs.  相似文献   

Effect of live fences of Gliricidia sepium on CO2 fluxes in tropical livestock systems          下载免费PDF全文

G. Villanueva‐López  F. Casanova‐Lugo  P. Martínez‐Zurimendi  D. Parsons  L. A. Aguilar‐Solís 《Soil Use and Management》2016,32(4):553-564

Live fences have the potential to improve microclimatic conditions, moderate soil CO₂ fluxes and function as carbon sinks. We quantified variation in soil CO₂ fluxes from livestock silvopastoral systems under the canopies of live fences (LF), formed by Gliricidia sepium trees, or artificial fences (AF). We determined the responses of soil CO₂ fluxes to environmental factors, including diurnal and seasonal variations in temperature and relative humidity in each fencing system. Measurements were made from April to June (dry season) and from July to September (rainy season), 2012. Fluxes were similar between the two livestock systems; LF emitted 1.00 μmol CO₂/m²/s and AF 1.02 μmol CO₂/m²/s. Soil temperatures at 5 cm depth were 3% warmer in AF than in LF, and relative humidity was 16% greater in LF than in AF. Seasonal variation in temperature greatly affected soil CO₂ fluxes, which changed seasonally in parallel with temperature of the topsoil and relative humidity at 1 m height, peaking in late summer. Fluxes in LF and AF were greater in the rainy season (1.1 μmol CO₂/m²/s, for both systems), when soil temperature was cooler and relative humidity was greatest, than during the dry season (0.9 μmol CO₂/m²/s, for both systems). Soil fluxes were larger at night (00:00–06:00 h), when soil temperature was cooler and relative humidity greater, than during the morning (6:00–12:00 h), when soil temperature was warmer and relative humidity was less. The presence of G. sepium trees in LF did not influence soil CO₂ fluxes.  相似文献   

IMAGING DIAGNOSIS—MUSCULAR HYPERTROPHY OF THE SMALL INTESTINE AND PSEUDODIVERTICULA IN A HORSE          下载免费PDF全文

Cristobal Navas De Solís  Elisabeth W. Biscoe  Caleb M. Lund  Karyn Labbe  Juan Muñoz  Kelly Farnsworth 《Veterinary radiology & ultrasound》2015,56(2):E13-E16

A 14‐year‐old Thoroughbred gelding was presented for chronic colic and weight loss. Transcutaneous and transrectal abdominal ultrasonography revealed distended, thickened small intestine with primary thickening of the muscularis and a focally more thickened loop with an echoic structure crossing the wall from the mucosa to the serosa. Visualization of diffuse thickening of the muscularis (muscular hypertrophy of the small intestine) and a focal lesion (pseudodiverticulum) helped clinicians make informed decisions. This case illustrates the importance of transabdominal and transrectal ultrasonography in horses with chronic colic and the relevance of considering the abnormalities in layering pattern of the intestinal wall.  相似文献   

Feed preference in pigs: effect of selected protein, fat, and fiber sources at different inclusion rates     

Solà-Oriol D  Roura E  Torrallardona D 《Journal of animal science》2011,89(10):3219-3227

Three double-choice feeding experiments were conducted to study the effect of different feedstuffs on feed preference in pigs. Fifteen protein sources, 6 fat sources, and 3 fiber sources were evaluated in Exp. 1, 2, and 3, respectively. Pigs were offered a series of double choices between a common reference diet and the diet with the ingredient under evaluation. The reference diet contained a soybean meal product with 56% CP (SBM-56), sunflower oil, and wheat bran, which were considered as the feedstuffs of reference for the protein, fat, and fiber sources, respectively. Preference, expressed as percentage of the tested diet to total feed intake, was affected by feedstuff nature and by its inclusion rate. In Exp. 1, feeds with fish meal at 50 and 100 g·kg?1, dried porcine hydrolyzed protein at 50 g·kg?1, and lupine, soybean meal with 44% CP, and dried skim milk at 100 g·kg?1 were preferred (P < 0.05) to the reference feed with SBM-56. On the contrary, relative to SBM-56, an avoidance (preference less than 50%) was observed for potato protein at all inclusion rates tested, rapeseed meal and acid milk whey at 100 and 200 g·kg?1, and dried porcine hydrolyzed protein, soybean protein concentrate, wheat gluten, and sunflower meal at 200 g·kg(-1). The storage of dried skim milk, soybean protein concentrate, and potato protein for 10 mo resulted in a reduction (P < 0.001) of their preference values. In Exp. 2, the feed with palm oil (at 30 g·kg?1) was preferred (P < 0.05), whereas feeds with linseed oil (at 30 and 100 g·kg?1) and soybean oil (at 100 g·kg?1) were avoided (P < 0.05) when contrasted with the reference feed with sunflower oil. Finally, in Exp. 3 diets with dehydrated alfalfa and sugar beet pulp at 130 g·kg?1 had a reduced (P < 0.05) preference compared with the reference diet with wheat bran. It is concluded that feedstuff nature, inclusion rate, and freshness affect feed preference in pigs. Feedstuff preferences should be taken into account during diet formulation, particularly at critical stages such as immediately after weaning.  相似文献   

Efficacy of a BVDV subunit vaccine produced in alfalfa transgenic plants     

María Sol Pérez Aguirreburualde  María Cristina Gómez  Agustín Ostachuk  Federico Wolman  Guillermo Albanesi  Andrea Pecora  Anselmo Odeon  Fernando Ardila  José M. Escribano  María José Dus Santos  Andrés Wigdorovitz 《Veterinary immunology and immunopathology》2013,151(3-4):315-324

Bovine viral diarrhea virus (BVDV) is considered an important cause of economic loss within bovine herds worldwide. In Argentina, only the use of inactivated vaccines is allowed, however, the efficacy of inactivated BVDV vaccines is variable due to its low immunogenicity. The use of recombinant subunit vaccines has been proposed as an alternative to overcome this difficulty. Different studies on protection against BVDV infection have focused the E2 protein, supporting its putative use in subunit vaccines. Utilization of transgenic plants expressing recombinant antigens for the formulation of experimental vaccines represents an innovative and cost effective alternative to the classical fermentation systems.The aim of this work was to develop transgenic alfalfa plants (Medicago sativa, L.) expressing a truncated version of the structural protein E2 from BVDV fused to a molecule named APCH, that target to antigen presenting cells (APCH-tE2). The concentration of recombinant APCH-tE2 in alfalfa leaves was 1 μg/g at fresh weight and its expression remained stable after vegetative propagation. A methodology based an aqueous two phases system was standardized for concentration and partial purification of APCH-tE2 from alfalfa. Guinea pigs parentally immunized with leaf extracts developed high titers of neutralizing antibodies. In bovine, the APCH-tE2 subunit vaccine was able to induce BVDV-specific neutralizing antibodies. After challenge, bovines inoculated with 3 μg of APCH-tE2 produced in alfalfa transgenic plants showed complete virological protection.  相似文献   

Understanding the effect of repeated administration of meloxicam on feline renal cortex and medulla: A lipidomics and metabolomics approach     

Sol M. Rivera‐Velez  Liam E. Broughton‐Neiswanger  Martin A. Suarez  Jennifer E. Slovak  Julianne K. Hwang  Jinna Navas  Amy W. S. Leung  Pablo E. Pieyro  Nicolas F. Villarino 《Journal of veterinary pharmacology and therapeutics》2019,42(4):476-486

Repeated administration of meloxicam can cause kidney damage in cats by mechanisms that remain unclear. Metabolomics and lipidomics are powerful, noninvasive approaches used to investigate tissue response to drug exposure. Thus, the objective of this study was to assess the effects of meloxicam on the feline kidney using untargeted metabolomics and lipidomics approaches. Female young‐adult purpose‐breed cats were allocated into the control (n = 4) and meloxicam (n = 4) groups. Cats in the control and meloxicam groups were treated daily with saline and meloxicam at 0.3 mg/kg subcutaneously for 17 days, respectively. Renal cortices and medullas were collected at the end of the treatment period. Random forest and metabolic pathway analyses were used to identify metabolites that discriminate meloxicam‐treated from saline‐treated cats and to identify disturbed metabolic pathways in renal tissue. Our results revealed that the repeated administration of meloxicam to cats altered the kidney metabolome and lipidome and suggest that at least 40 metabolic pathways were altered in the renal cortex and medulla. These metabolic pathways included lipid, amino acid, carbohydrate, nucleotide and energy metabolisms, and metabolism of cofactors and vitamins. This is the first study using a pharmacometabonomics approach for studying the molecular effects of meloxicam on feline kidneys.  相似文献   

Genetic and environmental risk factors for vitiligo and melanoma in Pura Raza Español horses     

M. J. Sánchez-Guerrero  M. Solé  P. J. Azor  J. Sölkner  M. Valera 《Equine veterinary journal》2019,51(5):606-611

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Field-testing and characterization of Technosols made from industrial and agricultural residues for restoring degraded slopes in semiarid SE Spain     

Luna Ramos  Lourdes  Solé Benet  Albert  Lázaro Suau  Roberto  Arzadun Larrucea  Amaia  Hens del Campo  Luis  Urdiales Matilla  Antonio 《Journal of Soils and Sediments》2021,21(5):1989-1997

Journal of Soils and Sediments - Many industries and agriculture generate huge amounts of wastes either mineral, organic or both, with environmental impact. Some of these residues have the...  相似文献   

Safety and efficacy of an E2 glycoprotein subunit vaccine produced in mammalian cells to prevent experimental infection with bovine viral diarrhoea virus in cattle     

Pecora A  Aguirreburualde MS  Aguirreburualde A  Leunda MR  Odeon A  Chiavenna S  Bochoeyer D  Spitteler M  Filippi JL  Dus Santos MJ  Levy SM  Wigdorovitz A 《Veterinary research communications》2012,36(3):157-164

Bovine viral diarrhea (BVD) infection caused by bovine viral diarrhea virus (BVDV), a Pestivirus of the Flaviviridae family, is an important cause of morbidity, mortality and economical losses in cattle worldwide. E2 protein is the major glycoprotein of BVDV envelope and the main target for neutralising antibodies (NAbs). Different studies on protection against BVDV infection have focused on E2, supporting its putative use in subunit vaccines. A truncated version of type 1a BVDV E2 (tE2) expressed in mammalian cells was used to formulate an experimental oleous monovalent vaccine. Immunogenicity was studied through immunisation of guinea pigs and followed by trials in cattle. Calves of 8-12?months were vaccinated, twice with a 4?week interval, with either a tE2 subunit vaccine (n?=?8), a whole virus inactivated vaccine (n?=?8) or left untreated as negative control group (n?=?8). Four weeks after the last immunisation the animals were experimentally challenged intranasally with a non-cythopathic BVDV strain. Following challenge, BVDV was isolated from all unvaccinated animals, while 6 out of 8 animals vaccinated with tE2 showed complete virological protection indicating that the tE2 vaccine presented a similar performance to a satisfactory whole virus inactivated vaccine.  相似文献