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排序方式: 共有434条查询结果,搜索用时 15 毫秒
1.
We describe the classification of landscapes characterised bymineral soil using a model that calculates soil moisture availability on amonthly basis. Scotland is used as a case study area. The model uses potentialsoil moisture deficit, estimated using broad scale (40 × 40 km)climate patterns, in conjunction with meteorological station measurements toobtain finer scale values of climatic soil moisture deficit. Point estimates ofsoil available water are obtained for soil characteristics using appropriatepedotransfer functions, and geostatistical techniques are used to upscale theresults and interpolate to a 1-km grid. Known heterogeneityin soil physical characteristics is used to provide local corrections to thepotential soil moisture deficit, estimated using the climatic variables above.Temporal profiles of monthly water content are modelled for each1-km location and classified into six classes usingunsupervised cluster analysis. The spatial distribution of these classesreflects regional variations in the availability of moisture and energy, onwhich finer-grained topographic patterns are superimposed. In the case study,the broad scale spatial heterogeneity of heathlands and grasslands on mineralsoils in Scotland is shown to be strongly related to the soil moistureclassification. The results can be used in studies investigating the patternsofdistribution of communities at the landscape and regional scale.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
2.
Iacopo Vannozzi Matteo Tesi Marta Zangheri Viola Maria Innocenti Alessandra Rota Simonetta Citi Alessandro Poli 《Veterinary research communications》2018,42(2):137-143
Ultrasonography is a valuable tool for the evaluation of neoplastic lesions in the dog and there is a growing interest in the use of this technique for the stadiation of canine mammary tumours. An accurate assessment of small sized nodules facilitates the stadiation of the mammary lesions and helps the clinician in the choice of the most indicated surgical therapy. The aim of this study was to identify those ultrasound criteria that may be useful in discriminating between benign and malignant lesions of small size (diameter smaller than 2 cm). Sixty-two nodules, < 2 cm in larger diameter, belonging to thirty-five bitches presented between January 2012 and February 2014 were evaluated. Tumours were observed by conventional ultrasound and assessed for: shape (regular-irregular), limit (defined-ill-defined), margins (regular-irregular), echogenicity (hypoechoic-isoechoic-hyperecoic), echotexture (homogeneus-heterogeneus), presence of hyperecoic halo, distal acoustic enhancement or shadowing and surrounding tissue alterations. Among the alterations in surrounding tissues, the disruption of the glandular tissue and the increase in echogenicity of the peritumoral tissues were assessed. Thereafter, bitches were subjected to mastectomy and nodules were evaluated histologically. None of the ultasound criteria considered in the current study showed a statistically significant relation with malignancy, except for the presence of alterations in the tissue surrounding the nodules. According to our results, this characteristic may indicate malignancy, however its subjectivity may affect the applicability in clinical practice. In conclusions, conventional ultrasound in bitches had a limited ability in discriminating benign and malignant mammary gland neoplastic lesions of small size (diameter?<?2 cm). 相似文献
3.
4.
Alessandro Vastolo Serena Calabrò Severina Pacifico Bossima Ivan Koura Monica Isabella Cutrignelli 《Journal of animal physiology and animal nutrition》2021,105(Z1):1-9
Cannabis sativa L. is an annual herbaceous plant. It was used for centuries to obtain different products. In the last century, hemp cultivation was forbidden due to the psychoactive effects of tetrahydrocannabinol acid (THCA). In the last years, new strains, characterized by high cannabidiolic acid (CBDA) and low THCA level, were developed renewing the interest in hemp cultivation to obtain food or to extract essential oils from flowers. All these processes produce many residues with different chemical–physical characteristics. In order to evaluate their potential use also in animal nutrition, some hemp co-products were evaluated. Two different co-products of seed processes (flour and oil) and two co-products obtained trimming the flowers, differing in granulometry were used. The samples were analysed for chemical composition and evaluated in vitro using the gas production technique with buffaloes' ruminal inoculum. All hemp co-products showed interesting nutritional characteristics, such as crude protein content always higher than 20% on a dry matter basis, and high neutral detergent fibre concentration partially lignified. The in vitro gas production parameters at 120 h of incubation showed quite low fermentability testified by the low organic matter degradability and cumulative gas volume (OMD from 28.09 to 45.64% and OMCV from 110 to 164 ml/g, respectively). Also, the methane produced after 24 h of incubation was particularly low (from 1.78 to 11.73 ml/g dOM). These results could be due to the high lipid and ash amounts or to the CBDA content that probably affected the CH4 formation processes. According to preliminary results obtained by this study, it is possible to hypothesize that these co-products could be useful to mitigate the methane production into the rumen. Further studies are necessary in order to evaluate the correct inclusion into the diet for ruminants. 相似文献
5.
Mingli LIN Mingming LIU Francesco CARUSO Massimiliano ROSSO Xiaoming TANG Lijun DONG Wenzhi LIN Anna BORRONI Alessandro BOCCONCELLI Liang DAI Songhai LI 《Integrative zoology》2021,16(4):440-450
A pioneering boat-based survey was conducted in 2019, to gather baseline information regarding the presence, composition, relative abundance, and spatial distribution of deep-diving and off-shore cetaceans in the northern South China Sea (SCS). A total of 27 sightings comprising at least 8 cetacean species were recorded during the 13-day survey, including 5 deep-diving species (i.e. Risso's dolphin [Grampus griseus], short-finned pilot whale [Globicephala macrorhynchus], sperm whale [Physeter macrocephalus], Cuvier's beaked whale [Ziphius cavirostris], and an unidentified beaked whale [either the ginkgo-toothed beaked whale, Mesoplodon ginkgodens, or Deraniyagala's beaked whale, Mesoplodon hotaula]), as well as 3 off-shore dolphins (i.e. pantropical spotted dolphin [Stenella attenuate], striped dolphin [Stenella coeruleoalba], and Fraser's dolphin [Lagenodelphis hosei]). With the exception of pantropical spotted dolphins, all other species were sighted and recorded at sea in the northern SCS for the first time. The pantropical spotted dolphin was the most frequently sighted species, comprising 30% of the total sightings. Deep-diving cetaceans were mainly sighted in the northern Xisha Archipelago, whereas off-shore dolphins were distributed across the survey area. The pantropical spotted dolphin was observed in aggregations of more than 100 individuals and nearly all encountered species included calves; these findings suggested that the survey area functions as an important feeding and calving ground for various cetacean species. This pioneering survey provides fundamental information regarding cetacean fauna in the northern SCS and highlights the need to strengthen research and conservation efforts concerning these species. 相似文献
6.
Alessandro Marchetti Chiara Piccini Sergio Santucci Igino Chiuchiarelli Rosa Francaviglia 《CATENA》2011,85(3):267-273
Soil surveys are an essential source of information for land management although a limited budget often reduces the amount of data available. Even if the dataset is limited, geostatistics can provide a valid estimation tool through a weighted moving average interpolation (kriging). Often, however, the spatial variability of soil properties appears smoothed and short range variability is underestimated by this kind of interpolation technique. A more realistic distribution of a given variable on the territory can be obtained through models based on stochastic simulation. 相似文献
7.
Aquaculture generates a large load of effluents rich in organic matter and nutrients that may be introduced into the environment. This study aimed to assess in a microcosm experiment, the effect of shrimp pond water mixed with Patos Lagoon estuary water on phytoplankton chlorophyll a and primary production, simulating two salinities. Chlorophyll a, dissolved inorganic nutrients and primary production were measured in two experiments. In Harvest I, salinity of shrimp pond and environment water was similar, and chlorophyll a showed different trends over time, according to the amount of nitrogen available. In Harvest II, with different salinities and high nutrient concentrations in environment water, chlorophyll a levels showed a similar increasing trend over time in all mixtures. Net primary production showed differences among treatments in the first sampling in Harvest I, but not in the second, whereas no differences were observed among treatments in Harvest II. We conclude that shrimp pond effluent can lead to short‐term variations in chlorophyll a and primary production levels, with similar salinities. Salinity differences result in lower chlorophyll a and primary production values than expected according to the nutrient input. Differences in salinity can be an important management strategy to choose the best harvest period. 相似文献
8.
Lacetera N Franci O Scalia D Bernabucci U Ronchi B Nardone A 《American journal of veterinary research》2002,63(7):958-962
OBJECTIVE: To assess effects on functions of peripheral blood mononuclear cells (PBMC) obtained from ewes for each of several fatty acids represented in ovine plasma at concentrations mimicking those of ketotic or healthy ewes. SAMPLE POPULATION: Blood samples obtained from 6 Sardinian ewes. PROCEDURE: The PBMC were cultured in media that contained oleic (OA), palmitic (PA), stearic (SA), linoleic (LA), or palmitoleic (POA) acid at concentrations similar to those of ketotic or healthy ewes. Synthesis of DNA was stimulated by use of concanavalin A or pokeweed mitogen (PWM). Secretion of IgM was stimulated by use of PWM. RESULTS: High concentrations (900, 450, and 225 micromol/L) of OA significantly inhibited DNA synthesis and IgM secretion of PBMC. Conversely, low concentrations (56 or 28 micromol/L) of OA significantly enhanced DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, or 75 micromol/L) significantly inhibited DNA synthesis of PBMC. High concentrations of PA (600, 300, 150, 75, 375, or 18.7 micromol/L) and SA (300, 150, 75, or 38 micromol/L) also significantly inhibited IgM secretion of PBMC. None of the concentrations of LA and POA affected PBMC functions. CONCLUSION AND CLINICAL RELEVANCE: Impaired immunoresponsiveness of ketotic ewes is likely associated with an increase of plasma concentrations of OA, PA, or SA and not with that of LA or POA. At physiologic concentrations, single fatty acids are likely to participate in modulation of immunoresponsiveness by exerting suppressive or stimulatory effects on immune cells. 相似文献
9.
Poli A Abramo F Barsotti P Leva S Gramiccia M Ludovisi A Mancianti F 《Veterinary parasitology》2002,106(3):181-191
A case of leishmaniosis in domestic cats (Felis catus domesticus) is described. The subject showed a nodular lesion on the eyelid. The diagnosis was achieved by serological, parasitological, and light and electron microscopic investigations. By molecular techniques the aetiological agent was identified as belonging to Leishmania infantum, the species implicated in human and canine leishmaniosis in southern Europe. A preliminary study on the prevalence of asymptomatic feline leishmaniosis, performed in the areas where the infected cat was identified, revealed a low seroprevalence of infection: only 1 (0.9%) of the 110 cat sera examined by indirect fluorescent antibody test was positive for anti-Leishmania antibodies. Because clinical signs in feline leishmaniosis are unspecific and similar to those observed in other diseases commonly found in this species, leishmaniosis must be added to the differential diagnosis by feline veterinary practitioners and adequate serologic and histopathologic investigations must be performed in endemic areas. 相似文献
10.
Alessandro Zanzotto Federica Autiero Diego Bellotto Gianluca Dal Cortivo Gianluca Lucchetta Michele Borgo 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(2):183-192
During a 6-year study, grapevine propagation materials and young grapevines were analysed to evaluate the presence of internal
wood discolouration and the occurrence of fungal species involved in Petri disease. The intensity of wood discolouration increased
with the ageing of the plants. The maximum incidence of dark streaks was observed in the rootstock while necrosis originating
from buds or nodes were notably present in the trunk and cordon of older vines. In contrast, the highest levels of brown-red
halo symptoms, defined as discoloured areas around the pith, were recorded in the early growth stages. Phaeoacremonium spp. and Phaeomoniella chlamydospora were usually isolated from the rooted-grafts and the 3-year old plants, respectively. The number of infected grapevines increased
with age. Most of the P. chlamydospora strains were isolated from dark streaks or dots, while Phaeoacremonium spp. were detected in brown-red halo symptoms and other symptomatic or asymptomatic wood. The greatest incidence of the two
fungal taxa was recorded in the lower parts of the grapevine, including the roots and rootstock. 相似文献