Mediastinal lymphoma in dogs is homogeneous compared to thymic epithelial neoplasia and is more likely to envelop the cranial vena cava in CT images     

Elizabeth J. Reeve  Emma K. Mapletoft  Frederike Schiborra  Thomas W. Maddox  Christopher R. Lamb  Chris M.R. Warren‐Smith 《Veterinary radiology & ultrasound》2020,61(1):25-32

In order to identify CT signs that could be used to distinguish cranial mediastinal lymphoma and thymic epithelial neoplasia, a retrospective case‐control study was done. Associations between CT signs and diagnosis were tested using binary logistic regression and results expressed as odds ratio and 95% confidence interval. Sixty‐two dogs that had thoracic CT and confirmed diagnosis of lymphoma (n = 33) or thymic neoplasia (n = 29) were sampled. Thymic neoplasms included 24 thymomas and five thymic carcinomas. Dogs with thymic epithelial neoplasia were significantly older than dogs with lymphoma (median age 8.6 years versus 6.0 years, P = .007), but there were no significant differences in prevalence of clinical signs. Diagnosis of thymic epithelial neoplasia was associated with heterogeneous attenuation in pre‐ (odds ratio 23.3, 95% confidence interval, 4.5‐121.1) and post‐contrast (odds ratio 30.7, 95% confidence interval, 3.6‐265.0) images. Conversely, envelopment of the cranial vena cava by the mass was less likely with thymic epithelial neoplasia than lymphoma (odds ratio 0.07, 95% confidence interval, 0.007‐0.66). Greater standard deviation of Hounsfield unit values in post‐contrast images was associated with thymic epithelial neoplasia (P = .005). Based on ROC analysis, SD > 17HU of the mass in post‐contrast images had a sensitivity of 72% and specificity of 79% for thymic epithelial neoplasia. There were no significant differences in morphology, prevalence of calcification, mediastinal lymphadenopathy, cranial vena cava invasion, collateral vessels, or pleural fluid associated with these tumors. Thymic epithelial neoplasms tended to occur in older dogs and were heterogeneous in CT images, whereas mediastinal lymphoma was more homogeneous and more likely to envelop the cranial vena cava.  相似文献   

Iris biopsy to investigate feline iris hyperpigmentation     

Heidi J. Featherstone  Emma J. Scurrell  Mike Rhodes  Rodrigo Pinheiro de Lacerda 《Veterinary ophthalmology》2020,23(2):269-276

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Impacts of the Cretaceous Terrestrial Revolution and KPg extinction on mammal diversification   总被引：1，自引：0，他引：1  

Meredith RW  Janečka JE  Gatesy J  Ryder OA  Fisher CA  Teeling EC  Goodbla A  Eizirik E  Simão TL  Stadler T  Rabosky DL  Honeycutt RL  Flynn JJ  Ingram CM  Steiner C  Williams TL  Robinson TJ  Burk-Herrick A  Westerman M  Ayoub NA  Springer MS  Murphy WJ 《Science (New York, N.Y.)》2011,334(6055):521-524

Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.  相似文献   

An assessment of noise audibility and sound levels in U.S. National Parks   总被引：1，自引：0，他引：1  

Emma Lynch  Damon Joyce  Kurt Fristrup 《Landscape Ecology》2011,26(9):1297-1309

Throughout the United States, opportunities to experience noise-free intervals are disappearing. Rapidly increasing energy development, infrastructure expansion, and urbanization continue to fragment the acoustical landscape. Within this context, the National Park Service endeavors to protect acoustical resources because they are essential to park ecology and central to the visitor experience. The Park Service monitors acoustical resources in order to determine current conditions, and forecast the effects of potential management decisions. By community noise standards, background sound levels in parks are relatively low. By wilderness criteria, levels of noise audibility are remarkably high. A large percentage of the noise sources measured in national parks (such as highways or commercial jet traffic) originates outside park boundaries and beyond the management jurisdiction of NPS. Many parks have adopted noise mitigation plans, but the regional and national scales of most noise sources call for conservation and management efforts on similar scales.  相似文献   

Avian community response to pine flatwoods management     

Emma V. Willcox  William M. Giuliano 《Forest Ecology and Management》2011,261(11):1928-1935

Across the southeastern United States, changing disturbance regimes threaten the integrity of pine flatwoods, reducing their suitability as habitat for a variety of avian species, many of which are considered of conservation priority. Prescribed burning and roller chopping are management practices widely used in pine flatwoods to control shrubs and increase the growth of herbaceous vegetation. However, the impacts these treatments have on this system and its associated avian communities are largely unknown. We examined the effects of prescribed burning and roller chopping on pine flatwoods avian communities using a paired sample approach. Avian communities were compared between treated (e.g., burned) and untreated areas. We considered abundance and richness of all birds, but also groups of conservation concern, and those likely impacted by seasonal management practices (e.g., breeding and non-breeding categories, and woodland, successional-scrub, and grassland guilds). Dormant season burning resulted in decreases in avian species richness and abundance within the non-breeding, overwintering community. In situations where the maintenance or enhancement of this avian group is desired, growing season burning appears beneficial and should be used in preference to dormant season burning. Growing season burning benefited breeding avian communities, resulting in increases in species richness and abundance within this group. Dormant season roller chopping had no effect on species richness or abundance of any avian category or guild. Increases in abundance within breeding avian communities were observed following growing season roller chopping and a roller chopping/burning combination. Grazing, did not mediate the effects of prescribed burning or roller chopping on avian species richness or abundance. The use of dormant season burning is likely inappropriate in situations where conservation and management of non-breeding, overwintering species is a priority. The use of growing season roller chopping appears to provide a potential treatment alternative in situations where positive effects on breeding species are desired. Overall, maintenance of avian abundance and richness may be best achieved through the diverse application of prescribed burning and roller chopping based on season, frequency, and space.  相似文献   

Direct liquid chromatography method for the simultaneous quantification of hydroxytyrosol and tyrosol in red wines     

Piñeiro Z  Cantos-Villar E  Palma M  Puertas B 《Journal of agricultural and food chemistry》2011,59(21):11683-11689

A validated HPLC method with fluorescence detection for the simultaneous quantification of hydroxytyrosol and tyrosol in red wines is described. Detection conditions for both compounds were optimized (excitation at 279 and 278 and emission at 631 and 598 nm for hydroxytyrosol and tyrosol, respectively). The validation of the analytical method was based on selectivity, linearity, robustness, detection and quantification limits, repeatability, and recovery. The detection and quantification limits in red wines were set at 0.023 and 0.076 mg L(-1) for hydroxytyrosol and at 0.007 and 0.024 mg L(-1) for tyrosol determination, respectively. Precision values, both within-day and between-day (n = 5), remained below 3% for both compounds. In addition, a fractional factorial experimental design was developed to analyze the influence of six different conditions on analysis. The final optimized HPLC-fluorescence method allowed the analysis of 30 nonpretreated Spanish red wines to evaluate their hydroxytyrosol and tyrosol contents.  相似文献   

Transient regenerative potential of the neonatal mouse heart   总被引：2，自引：0，他引：2  

Porrello ER  Mahmoud AI  Simpson E  Hill JA  Richardson JA  Olson EN  Sadek HA 《Science (New York, N.Y.)》2011,331(6020):1078-1080

Certain fish and amphibians retain a robust capacity for cardiac regeneration throughout life, but the same is not true of the adult mammalian heart. Whether the capacity for cardiac regeneration is absent in mammals or whether it exists and is switched off early after birth has been unclear. We found that the hearts of 1-day-old neonatal mice can regenerate after partial surgical resection, but this capacity is lost by 7 days of age. This regenerative response in 1-day-old mice was characterized by cardiomyocyte proliferation with minimal hypertrophy or fibrosis, thereby distinguishing it from repair processes. Genetic fate mapping indicated that the majority of cardiomyocytes within the regenerated tissue originated from preexisting cardiomyocytes. Echocardiography performed 2 months after surgery revealed that the regenerated ventricular apex had normal systolic function. Thus, for a brief period after birth, the mammalian heart appears to have the capacity to regenerate.  相似文献   

Schemas and memory consolidation   总被引：1，自引：0，他引：1  

Tse D  Langston RF  Kakeyama M  Bethus I  Spooner PA  Wood ER  Witter MP  Morris RG 《Science (New York, N.Y.)》2007,316(5821):76-82

Memory encoding occurs rapidly, but the consolidation of memory in the neocortex has long been held to be a more gradual process. We now report, however, that systems consolidation can occur extremely quickly if an associative "schema" into which new information is incorporated has previously been created. In experiments using a hippocampal-dependent paired-associate task for rats, the memory of flavor-place associations became persistent over time as a putative neocortical schema gradually developed. New traces, trained for only one trial, then became assimilated and rapidly hippocampal-independent. Schemas also played a causal role in the creation of lasting associative memory representations during one-trial learning. The concept of neocortical schemas may unite psychological accounts of knowledge structures with neurobiological theories of systems memory consolidation.  相似文献   

Femtotesla magnetic field measurement with magnetoresistive sensors     

Pannetier M  Fermon C  Le Goff G  Simola J  Kerr E 《Science (New York, N.Y.)》2004,304(5677):1648-1650

The measurement of magnetic fields in the femtotesla (fT, 10(-15) tesla) range is important for applications such as magnetometry, quantum computing, solid-state nuclear magnetic resonance, and magnetoencephalography. The only sensors capable of detecting these very small fields have been based on low-temperature superconducting quantum interference devices operating at 4.2 kelvin. We present a magnetic field sensor that combines a superconducting flux-to-field transformer with a low-noise giant magnetoresistive sensor. The sensor can be operated up to 77 kelvin. Our small-size prototype provides the capability of measuring 32 fT.  相似文献   

The history and distribution of nodulating Paraburkholderia,a potential inoculum for Fynbos forage species     

Chrizelle W. Beukes  Stephanus N. Venter  Emma T. Steenkamp 《Grass and Forage Science》2021,76(1):10-32

Legumes in the Fynbos vegetation of the Western Cape of South Africa have emerged as candidates for domestication, particularly for their adaptation to acidic and infertile soils. However, South African rhizobia have been shown to be very diverse and unique, and a detailed understanding of them is essential to success in forage breeding programs that seek to exploit these “new” legumes. Symbionts of legumes in South Africa that belong to traditional rhizobial genera have been shown to have a unique origin for their symbiotic loci in comparison to members sampled from other regions of the world. Some of the legume tribes in the Fynbos have also been shown to associate predominantly with unique species in the Betaproteobacterial genus Paraburkholderia. The rhizobial members of this genus have two main centres of diversity, of which South Africa is one. In this centre, the legume hosts are principally from the Papilionoideae subfamily while hosts from the mimosoid clade (now in the Caesalpinioideae) are abundant in the South American centre. Not only do these rhizobia differ in terms of host, but their symbiotic loci also show separate origins. The dominance and uniqueness of the Paraburkholderia symbionts, in the context of indigenous South African legumes, makes understanding the history and factors that affect the distribution of this genus essential if successful adaptation and effective nodulation of these legumes in Agriculture are to be achieved globally.  相似文献