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751.
Canopy fuel characteristics in relation to crown fire potential in pine stands: analysis, modelling and classification 总被引:1,自引:0,他引:1
José María Fernández-Alonso Iciar Alberdi Juan Gabriel Álvarez-González José Antonio Vega Isabel Cañellas Ana Daría Ruiz-González 《European Journal of Forest Research》2013,132(2):363-377
Crown fire occurrence and subsequent crown fire behaviour are strongly dependent on canopy fuel characteristics, especially canopy fuel load (CFL), canopy bulk density (CBD) and canopy base height (CBH). Therefore, quantification of such variables is required for the appropriate selection of silvicultural treatments aimed at reducing susceptibility to crown fire. Data from the IV Spanish National Forest Inventory and individual tree biomass dry weight equations were used to estimate the canopy fuel characteristics of four representative types of pine stands in north-western Spain. Probability of crown fire initiation and crown fire rate of spread were simulated by using the mean surface fuel load observed for each type of pine in this area and assuming different burning conditions. The results indicate that a 22.13 % of the sample plots analysed showed a rather high potential for active crown fire spread under moderate burning conditions, and this value increases to 69.27 % under extreme burning conditions. Equations relating the canopy fuel characteristics to common stand variables (stand density, basal area and dominant height) were fitted simultaneously for each pine, and weighting factors for heteroscedasticity were included. The models explained more than 93.90, 74.70 and 69.42 % of the observed variability in CFL, CBD and CBH, respectively. Basal area was the most important variable for estimating CFL and CBD while dominant height explained most of the observed variability in CBH. The use of the fitted equations together with existing dynamic growth models and fire management decision support systems will enable assessment of the crown fire potential associated with different silvicultural alternatives used in these types of pine stands. 相似文献
752.
Catarina Sofia Aluai-Cunha Catarina Alves Pinto Isabel Alexandra Duarte Ferreira Lopes Correia Cláudia Alexandra dos Reis Serra Andreia Alexandra Ferreira Santos 《Veterinary and comparative oncology》2023,21(2):166-183
Cancer is a substantial global health problem both in humans and animals with a consistent increase in mortality and incidence rate. The commensal microbiota has been involved in the regulation of several physiological and pathological processes, both within the gastrointestinal system and at distant tissue locations. Cancer is not an exception, and different aspects of the microbiome have been described to have anti- or pro-tumour effects. Using new techniques, for example high-throughput DNA sequencing, microbial populations of the human body have been largely described and, in the last years, studies more focused on companions' animals have emerged. In general, the recent investigations of faecal microbial phylogeny and functional capacity of the canine and feline gut have shown similarities with human gut. In this translational study we will review and summarize the relation between the microbiota and cancer, in humans and companion animals, and compare their resemblance in the type of neoplasms already studied in veterinary medicine: multicentric and intestinal lymphoma, colorectal tumours, nasal neoplasia and mast cell tumours. In the context of One Health, microbiota and microbiome integrative studies may contribute to the understanding of the tumourigenesis process, besides offering an opportunity to develop new diagnostics and therapeutic biomarkers both for veterinary and human oncology. 相似文献
753.
Over the past decades, empirical evidence has been accumulated indicating that olfactory information plays a fundamental role in bird life history. Nonetheless, many aspects of avian olfaction remain poorly understood. Our purpose was to broaden the knowledge about the importance of the sense of smell in some neglected bird groups: psittaciformes and ramphastids, and to compare how the response varied between the species. Because of the lack of information about the use of chemical cues for locating food in fruit-eating species, we also aimed to delve into this question. We conducted a 3-choice (water/vinegar/papaya and banana juice) scent test in 5 Costa Rican native species: scarlet macaw (Ara macao), red-lored amazon (Amazona autumnalis), yellow-naped amazon (Amazona auropalliata), keel-billed toucan (Ramphastos sulfuratus), and yellow-throated toucan (Ramphastos ambiguus). Results revealed that macaws and toucans allocated significantly more time to interacting with the fruit scent container, indicating that these species can perceive the volatile chemicals emitted by ripe fruits and that they can use this information to make foraging decisions. However, amazons did not dedicate more time to interact with the fruit treatment. Our research provides the first evidence of the ability to exploit chemical volatile cues in macaws and toucans. 相似文献
754.
White WH Gutierrez JA Naylor SA Cook CA Gonzalez IC Wisehart MA Smith CK Thompson WA 《Veterinary parasitology》2007,146(1-2):58-65
The neurotransmitter serotonin (5-hydroxy tryptamine or 5HT) regulates key physiological processes in nematodes such as locomotion and feeding. PAPP (p-amino-phenethyl-m-trifluoromethylphenyl piperazine) is a known agonist of the 5-HT(1Hc) receptor of the barber pole worm, Haemonchus contortus. In this study, PAPP was highly active against L3-stage larvae of H. contortus and Trichostrongylus colubriformis in an in vitro larval migration assay, with EC50 values of 9.36 and 11.8 microM, respectively, that were comparable to levamisole (10.2 microM) and superior to pyrantel (55.39 microM). When administered orally or subcutaneously to nematode infected gerbils, PAPP provided >99% efficacy against H. contortus and >98% efficacy against Teladorsagia circumcincta at 100 mg/kg, comparable to levamisole at 10 mg/kg. Drug titration revealed significant activity down to 50 mg/kg against these two species. Spectrum was limited, however, with somewhat lower efficacy (83%) in T. colubriformis infected gerbils at 100 mg/kg. Oral delivery of hydrochloride, acetate and phosphate salts of PAPP to nematode infected gerbils did not result in an increase in either potency or spectrum. The finding that PAPP exhibits significant anthelmintic activity suggests that the nematode-specific serotonergic system is a viable target for future anthelmintic discovery. 相似文献
755.
de Souza Rosés Thiago Andreolla Ana Paula de Figueiredo Soveral Lucas Vieira Maria Isabel Botelho Kich Jalusa Deon Frandoloso Rafael Kreutz Luiz Carlos 《Tropical animal health and production》2020,52(2):619-623
Tropical Animal Health and Production - Trichinellosis is a zoonotic disease exotic in Brazil but commonly found worldwide including South American countries like Argentina. International trading... 相似文献
756.
Claudia Kasper Isabel Ruiz-Ascacibar Peter Stoll Giuseppe Bee 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(6):545-558
Pig production contributes to environmental pollution through excretion of phosphorus and nitrogenous compounds. European pig production requires annual imports of currently 36 million tons of soya bean, because domestic plant protein sources often do not meet the required protein quality. Most of the mineral phosphate sources are also imported. It is therefore desirable to improve nutrient deposition efficiency through selective breeding, that is to realise similar growth rates and carcass compositions as currently achieved but with a lower intake of dietary crude protein or phosphate. For a preliminary evaluation of the potential of selecting for increased nutrient deposition efficiency, we estimated genetic parameters for nitrogen and phosphorus efficiencies in a Swiss Large White pig population including 294 individuals. Nutrient efficiency phenotypes were obtained from wet-chemistry analyses of pigs of various live weights. Heritability of nitrogen efficiency was estimated at 41%. Heritability of phosphorus efficiency was very low (0.3%), but positive genetic correlations with nitrogen efficiency suggest that breeding for nitrogen efficiency would positively affect phosphorus efficiency. Further studies are needed to improve the quality of estimates and to obtain accurate high-throughput measures of nutrient efficiency to be implemented on farms. 相似文献
757.
Luiz Guilherme Corsi Trautwein Anne Kemmer Souza Guilherme Schiess Cardoso Karina Keller Marques da Costa Flaiban Antonio Cezar de Oliveira Dearo Maria Isabel Mello Martins 《Reproduction in domestic animals》2020,55(6):720-725
Sperm quality can be affected by a reduction in testicular blood flow, which can be measured by Doppler ultrasonography. The aim of this study was to correlate the Doppler velocimetry of the testicular artery with kinetics of the epididymal spermatozoa in dogs. Twenty-two dogs (44 testicles) were evaluated by Doppler ultrasonography in five regions of the testicular artery before orchiectomy. Spermatozoa were recovered by the epididymal tail compression technique and analysed for kinetics on a computer-assisted semen analysis (CASA system). Morphology (modified Karras) and sperm membrane integrity were analysed by eosin–nigrosine staining. Data were analysed by Pearson's correlation test (p < .01). The mean total motility was 69.0% ± 17.7, progressive motility was 43.7% ± 14.7, average path velocity (VAP) was 127.0 µm/s ± 20.7, curvilinear velocity (VCL) was 221.0 µm/s ± 31.1, and sperm velocity index (SVI) was 389.9 ± 56.1. There were positive correlations between the peak systolic velocity (PSV) in the proximal supratesticular region with the SVI (r = .529), VCL (r = .555) and VAP (r = .473), and a negative correlation with the percentage of slow spermatozoa (r = −.463). The results suggest that the testicular artery blood flow velocity can positively affect the speed of spermatozoa movement. For the first time, we have correlated sperm kinetics with the Doppler evaluation of the testicular artery in dogs. 相似文献
758.
Ana Piñeiro Mª Carmen Hernández Gema Silván Juan Carlos Illera Isabel Barja 《Reproduction in domestic animals》2020,55(12):1784-1793
Integrating ecophysiological and behavioural discoveries in conservation and management plans is essential to preserve scarce and elusive species such as the European wildcat (Felis silvestris). The purpose of this study was to characterize the monthly variation in the steroid reproductive hormone metabolite levels (oestradiol, progesterone and testosterone) in this species and to test its possible association with a monthly pattern of faecal marking. By collecting fresh faecal samples in Montes do Invernadeiro Natural Park (Galicia, Northwest Spain) each month, we obtained a total of 110 samples belonging to 25 different individuals. We conducted enzyme immunoassays which allowed us to track the annual variation in reproductive hormone excretion patterns in wildcat scats. Furthermore, we also evaluated the possible relation between the faeces used as marks and the reproductive hormone levels. We found that oestradiol and progesterone metabolite levels exhibited a distinct pattern, both increasing during the breeding months. Oestradiol metabolite larger peaks were found during March and April, whereas the highest concentration of progesterone metabolites appeared in July. On the contrary, testosterone metabolite levels did not significantly change depending on the month. Moreover, we did not find any evidence that the faecal marking behaviour pattern was associated with reproductive hormone metabolite levels. It seems that other factors related to habitat and food resources could be more important in the performance of this behaviour. 相似文献
759.
760.
The aim of this study was to examine the effect of administering an anti‐gonadotropin‐releasing hormone vaccine (Improvac®, developed for pigs) on the performance, temperament, testicular development, and hormone and metabolite profiles of feral bulls (Bos taurus) vaccinated at two different live weights (LW). In all, 16 Serrana de Teruel animals were involved in this 2 x 2 factorial design using the factors LW (LIGHT vs. HEAVY) and vaccine treatment (control, C vs. vaccinated, VA). All animals received the same diet (ad libitum concentrate plus straw) over a 164‐day fattening period. Temperament was assessed using chute and flight speed tests. Testicular diameter and subcutaneous fat thickness were recorded. Testosterone, IGF‐1, urea, NEFA, and creatinine profiles were analyzed. Bull weight gain was reduced in VA compared to C animals, regardless of the initial LW. The vaccine did not affect the temperament tests, subcutaneous fat thickness or NEFA and creatinine concentrations and had minor effects on linear body measures. The vaccine inhibited testicular growth, reduced plasma testosterone to residual levels, and increased urea concentrations. LIGHT‐C animals exhibited increased mean plasma IGF‐1 concentrations compared to LIGHT‐VA animals. In conclusion, vaccination reduced bull growth and sexual development irrespective of LW at immunization. 相似文献