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991.
992.
James Rodríguez-Echeverry Cristian Echeverría Carlos Oyarzún Luis Morales 《Landscape Ecology》2018,33(3):439-453
Context
Land-use change impacts biodiversity and ecosystem services, which are intrinsically related. There is a serious lack of knowledge concerning on how land-use change affects this relationship at landscape level, where the greatest impacts have been reported. A proper knowledge of that relationship would provide crucial information for planning conservation strategies. The forest landscape of southern Chile, which includes Valdivian Temperate Forest, has been designated as a hotspot for biodiversity conservation. However, this landscape has been transformed by land-use change.Objective
We evaluated the impact of land-use change on the spatial patterns of the diversity of native forest habitat and the influence of these impacts on the provision of the ecosystem services water supply, erosion control, and organic matter accumulation from 1986 to 2011.Methods
The evaluation, at the landscape level, was carried out using satellite images, landscape metrics, spatially explicit models and generalized linear models. Results: We found that the area loss of native forest habitat was 12%, the number patches of native forest habitat increased more than 150% and the Shannon diversity index decreased by 0.20. The largest decrease in the provision of services was recorded for erosion control (346%), and the smallest for water supply (11%).Conclusions
The loss of provision of the ecosystem services can be explained by the interaction between the area loss, increase in the number patches and diversity loss. We recommend that the conservation planning strategies should consider the current landscape configuration, complemented with land-use planning.993.
Albendazole treatment in laying hens: Egg residues and its effects on fertility and hatchability 下载免费PDF全文
Laura Moreno Mariana Bistoletti Hector Fernández Lucila Cantón Laura Ceballos Candela Cantón Carlos Lanusse Luis I. Álvarez 《Journal of veterinary pharmacology and therapeutics》2018,41(5):726-733
This work characterized the egg residual concentrations of albendazole (ABZ ) and its sulphoxide (ABZSO ) and sulphone (ABZSO 2) metabolites and evaluated their effect on egg fertility and hatchability after ABZ treatments to laying hens. Seventy hens were allocated in groups: Group‐1 was the control without treatment; Group‐2 received a single ABZ oral dose (10 mg/kg); Group‐3, ‐4 and ‐5 were treated with ABZ in medicated feed over 7 days at 10, 40, or 80 mg kg?1 day?1, respectively. Eggs were analyzed to determine the ABZ /metabolite level by HPLC or subjected to incubation to evaluate the fertility and hatchability. Only ABZSO and ABZSO 2 metabolites were quantified in egg after ABZ single oral administration with maximum concentrations of 0.47 ± 0.08 and 0.30 ± 0.07 μg/ml, respectively. ABZ and its metabolites were found in eggs after 7‐day ABZ treatments. The egg residue exposure estimated as AUC s (areas under the concentration vs . time curve) were 100.5 (ABZ ), 56.3 (ABZSO ) and 141.3 μg hr g?1 (ABZSO 2). ABZ administration did not affect the egg fertility at any dosages. Egg hatchability was not affected by ABZ treatment at 10 mg/kg in medicated feed, but it decreased when the dose was 4–8 times higher. These results should be considered when ABZ is used for deworming laying hens. 相似文献
994.
Manuel Martin-Flores Daniel M. Sakai Chia T. Tseng Robin D. Gleed Luis Campoy 《Veterinary anaesthesia and analgesia》2019,46(2):182-187
Objective
To assess the ability to visually detect fade during train-of-four (TOF) or double burst stimulation (DBS) in anesthetized dogs recovering from nondepolarizing neuromuscular block.Study design
Online anonymous survey.Population
Data from 112 participants.Methods
A web-based survey containing 12 videos of the response to ulnar nerve stimulation with TOF and 12 with DBS obtained at different levels of recovery from rocuronium-induced block was distributed to participants of the American College of Veterinary Anesthesia and Analgesia and the Academy of Veterinary Technicians in Anesthesia and Analgesia e-mail lists. Participants were asked to provide their highest training degree in anesthesiology, watch each video no more than twice, and determine whether fade was present. The probability to correctly recognize fade was calculated using binomial general linear models. General linear models and Tukey’s tests were used to assess the effects of level of neuromuscular block, pattern of stimulation, and observers’ training on the probability to detect fade.Results
The survey was completed by 53 diplomates, 29 licensed veterinary technicians, 24 residents and six doctors of veterinary medicine (DVMs). The probability to detect fade decreased as partial neuromuscular block became more shallow (p < 0.0001). A TOF or DBS ratio of 0.7 had a 50% chance of being detected. DBS was superior to TOF for detecting fade when the ratio was 0.3–0.69. TOF was superior to DBS when the ratio was 0.7–0.9 (p < 0.0001). There were no differences among groups of observers when assessing fade with TOF or DBS.Conclusions and clinical relevance
Detection of fade from observations of the response to TOF in dogs is unreliable. Advance training in anesthesiology or the use of DBS confers little to no advantage for this subjective test. 相似文献995.
Alessandra P.S. Salimena Carla C. Lange Cecilia Camussone Marcelo Signorini Luis F. Calvinho Maria A.V.P. Brito Cristiano A.V. Borges Alessandro S. Guimarães João B. Ribeiro Letícia C. Mendonça Roberta H. Piccoli 《Veterinary research communications》2016,40(3-4):97-106
Staphylococcus aureus is a pathogen that frequently causes mastitis in bovine herds worldwide. This pathogen produces several virulence factors, including cell-associated adhesins, toxic and cytolytic exoproteins, and capsular polysaccharides. The aim of the present study was to test for the presence of genes involved in capsular polysaccharide production and biofilm formation in S. aureus isolated from bovine mastitis samples collected from 119 dairy herds located in three different Brazilian regions, as well as to assay the production of capsular polysaccharides and biofilm, in vitro. The detection of the cap, icaAD, and bap genes was performed using PCR. The detection and quantification of capsular polysaccharide production was performed using ELISA assays. The ability of the isolates to form a biofilm was examined using the polystyrene surface of microtiter plates. All 159 S. aureus isolates investigated harboured the cap gene: 80 % carried the cap5 gene and 20 % carried the cap8 gene. Sixty-nine percent of the isolates expressed capsular polysaccharide (CP) in vitro, 58 % expressed CP5 and 11 % expressed CP8. All of the isolates harboured the icaA and icaD genes, and 95.6 % of the isolates carried the bap gene. Of the 159 isolates analysed, 97.5 % were biofilm producers. A significant association between the capsular genotype and phenotype and the amount of biofilm formation was detected: cap5/CP5 isolates tended to form more biofilm and to produce a thinner CP layer than cap8/CP8 isolates. The results indicate a high potential for pathogenicity among S. aureus isolated from bovine milk collected from three different regions in Brazil. 相似文献
996.
Luis Vargas-Chacoff Francisco J Arjona Ignacio Ruiz-Jarabo Inês Páscoa Odete Gonçalves María P Martín del Río & Juan Miguel Mancera 《Aquaculture Research》2009,40(11):1279-1290
Seasonal variations in osmoregulatory and metabolic parameters were assessed in juvenile gilthead sea bream ( Sparus auratus ) cultured in earthen ponds under a natural photoperiod and temperature. Specimens were sampled, and the plasma, gill, kidney and liver were collected during winter 2005 and 2006 (January), spring 2005 (April), summer 2005 (July) and autumn 2005 (October). Plasma osmoregulatory parameters showed higher values in summer, while metabolic parameters presented different patterns of variations. Gill Na+ ,K+ -ATPase activity decreased significantly in winter, while gill metabolite levels showed different patterns of variations among seasons. The enzymatic activities tested did not present a clear pattern of variation [(glutamate dehydrogenase (EC 1.4.1.2) (GDH) and hexokinase (EC 2.7.1.11) (HK)] or significant differences along seasons [glucose 6-phosphate dehydrogenase (EC 1.1.1.49)]. Kidney Na+ ,K+ -ATPase activity decreased during summer and autumn. Different patterns of variation were observed in kidney metabolite levels while all the enzymatic activities assessed [lactate dehydrogenase-oxidase (EC 1.1.1.27) (LDH-O), HK and GDH] presented the highest values during summer. In the liver, metabolite levels and enzymatic activities did not show significant variations or present clear patterns of variation along different seasons. These results indicated seasonal variations in the osmoregulatory and metabolic parameters of different organs (blood, gill, kidney and liver) in earthen pond-cultured gilthead sea bream ( S. auratus ), which could be mainly attributed to seasonal changes in temperature. 相似文献
997.
Genta Yasunaga Luis A. Pastene Takeharu Bando Takashi Hakamada Yoshihiro Fujise 《Fisheries Science》2017,83(6):947-954
Counting of the growth layers in the earplugs is the most accepted technique for determining chronological age of Antarctic minke whales; however, unreadable growth layers form in some individuals, especially in young animals. In this study, aspartic acid racemization (AAR) technique was developed for estimating ages in this species with the aim of complementing the age estimated using earplugs. To validate the technique and to determine the specific coefficients for age estimation, the ratio of d and l-enantiomers of aspartic acid (Asp D/L) in lens of 18 whales and 20 fetuses were analyzed and compared with earplug-based age estimates. The equation for age estimation by AAR in this species was as follows: Loge{[1 + (Asp D/L)act]/[1 ? (Asp D/L)act]} = 2.30 × 10?3 × earplug age (year) + 0.0201 (p < 0.001, r 2 = 0.918). There is a strong correlation between the age estimates by AAR and earplugs. This study was successful in developing the AAR technique for the Antarctic minke whale, and the application of this technique can complement the age estimation of this species based on earplug readings, especially for young animals with unreadable earplugs. 相似文献
998.
Aléssio Batista Miliorini Luis David Solis Murgas Priscila Vieira Rosa Guilherme Oberlender Gilmara Junqueira Machado Pereira Diego Vicente da Costa 《Aquaculture Research》2011,42(2):177-187
The present study evaluated some cryoprotectants and concentrations for curimba (Prochilodus lineatus) semen preservation from a simple methodology of analysis of sperm morphology. Semen of nine males was diluted (1:4) into eight cryosolutions, all of them containing 5% of BTS? Minitüb, still comprising methanol or dimethyl sulphoxide (DMSO) at four concentrations: 5%, 7.5%, 10% and 12.5%. Morphological sperm analysis was performed on an optical microscope at × 1000 magnification. Damages on the head, midpiece and tail rest (the main and terminal portions) were investigated and classified as primary or secondary, according to the assumed influence on fertilization. There was a linear reduction in the total damages with an increase in the cryoprotectant concentration. Samples with DMSO showed the lowest percentage of fractured tails and tail stumps. The cryopreservation protocol retained the fertilizing potential of the sperm after freezing and both methanol 5% and DMSO 7.5% conferred adequate protection to the curimba sperm cells. Sperm morphology, as pointed out here, must be incorporated into routine fish sperm (cryopreserved or not) analysis once sperm defects influence fertilization directly. To the best of our knowledge, this was the first report on curimba sperm damages after cryopreservation by optical microscopy. The classification model presented in this study can be adequate to tackle fish sperm damages. 相似文献
999.
Luis R Martínez‐Córdova José A López‐Elías Guadalupe Leyva‐Miranda Luis Armenta‐Ayón Marcel Martinez‐Porchas 《Aquaculture Research》2011,42(10):1415-1423
Shrimp aquaculture effluents were bioremediated in a two‐phase system (System A) using the black clam Chione fluctifraga and the benthic microalgae Navicula sp., and then reused to farm whiteleg shrimp Litopenaeus vannamei. In the experimental design, Systems B and C had an identical structure as System A, but no clams or microalgae were added. System B received the same shrimp effluents while System C received only estuarine water. Shrimp raw effluents had a poor water quality. System A improved the water quality by decreasing the concentrations of total nitrogen, total ammonia nitrogen (TAN), nitrites, nitrates, phosphates, total suspended solids (TSS) and organic suspended solids (OSS). System B also decreased the concentration of TAN, TSS and OSS via sedimentation, but the effect was less pronounced than that observed in System A. Shrimp reared in the bioremediated effluents (System A) had better production (3166 kg ha?1) and higher survival (89.2%) than those reared in effluents from Systems B (2610 kg ha?1, 75.1%) and C (2874 kg ha?1, 82.1%). It is concluded that the bioremediation system was moderately efficient and the bioremediated effluents were suitable to farm L. vannamei. 相似文献
1000.
Jesús Cacho Inmaculada Fierro Luis Debn Marisol Vega Rafael Pardo 《Pest management science》1999,55(9):949-954
The photochemical degradation of metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one) and imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine) has been investigated by differential-pulse polarography (DPP) and micellar electrokinetic chromatography (MEKC); the degradation pathways of these pesticides were elucidated and their degradation products proposed. The electrochemical study of imidacloprid by DPP at different pH values demonstrated the occurrence of two different reduction processes; at pH 6.8, two peaks at −0.90 V and −1.38 V, respectively, were obtained, which are related to the photochemical reduction processes. The photochemical degradation of imidacloprid caused by sunlight was polarographically monitored and its degradation products elucidated. The polarographic reduction of deaminometamitron (obtained by photochemical reduction of metamitron) yielded two peaks at −0.62 and −1.37 V, which are related to the reduction of the CN bonds. The effect of sunlight on the reduction of metamitron was monitored by DPP, and an increase of the concentration of the degradation products was observed with time. MEKC with UV-visible detection was used to separate the pesticides and the products of their photochemical degradation, which were identified in combination with DPP. © 1999 Society of Chemical Industry 相似文献