Impact of three silvicultural treatments on growth,light-energy processing,and related needle-level adaptive traits of Pinus strobus from two regions     

John E. Major  Alex MosselerDebby C. Barsi  Britt Corriveau-DupuisMoira Campbell 《Forest Ecology and Management》2009

Our goal was to quantify and compare the impact of three silvicultural treatments (STs) on growth, light-energy processing, and needle-level morphological adaptive traits for eastern white pine (Pinus strobus L.) from large, central Ontario (ON) and small, isolated Newfoundland (NL) populations. The interest in STs is to reduce weevil (Pissodes strobi) incidence; however, there are potential adaptive changes and productivity trade-offs. The light levels for the STs were, on average, 100%, 42.0%, and 20.4% transmittance for the full-sun, and intermediate- and high-shade STs, respectively. After 8 years, overall height growth was 4.10, 3.25, and 1.70 m for full-sun, and intermediate- and high-shade STs, respectively (P < 0.001). Across all STs, ON populations had greater total height (14%), basal diameter (12%), current leader length (25%), and tree volume (49%) than NL populations (all P < 0.001). At low light levels (10 and 25 μmol m⁻² s⁻¹), high-shade ST trees had higher photochemical quenching (qP) and lower chlorophyll fluorescence (F_pc) compared with intermediate-shade and full-sun STs. At 100 μmol m⁻² s⁻¹ and beyond, full-sun ST trees had higher qP and lower F_pc than intermediate- and high-shade STs. Average total chlorophyll concentration (CHL) and content (CHLC), and carotenoid concentration (CAR), increased in response to the intermediate-shade ST but did not respond further, or decreased in the high-shade ST. Region was significant for CHL, CAR, chlorophyll a:b and CHL:CAR ratios and CHLC, with ON greater than NL, but was reversed for CHL:CAR ratio. Tree height and volume showed a curvilinear and linear relationship to light level, respectively. Tree height showed a positive linear relationship to qP, apparent photosynthesis, chlorophyll a:b ratio, and needle N (all P < 0.001). Tree height showed a negative linear relationship to F_pc, CHL:CAR ratio, specific needle area, C:N ratio, and needle area N⁻¹ (all P < 0.001). There were modest trade-offs between weevil protection and productivity in the intermediate ST due to the compensatory physiological and morphological adaptations to the limiting light, however, the trade-off with growth at the high-shade level was severe. For NL, consideration should now be given to the introduction and mixing of seed from local seed sources with more southern mainland seed sources, which would decrease the inbreeding effect and provide wider variation for natural selection for a more fit future population.  相似文献   

Liming as an ameliorator of copper toxicity in black oat (Avena strigosa Schreb.)     

Vítor Gabriel Ambrosini  Daniel José Rosa  Alex Basso  Marcelo Borghezan  Rosete Pescador  Alcione Miotto 《Journal of plant nutrition》2017,40(3):404-416

This study aimed to assess the effect of liming as an ameliorator of copper (Cu) toxicity in black oats (Avena strigosa Schreb.) grown in soil with a sandy texture. The treatments were soil supplementation with increasing doses of lime (0.0, 0.5 and 1.0 g kg^?1) and two of Cu (0 and 50 mg kg^?1). Pre-germinated black oat seeds were sown for 30 days in the soil, subsequently, the plant height, root and shoot dry mass and concentration of total chlorophyll, chlorophylls a and b, carotenoids and total soluble carbohydrates and starch were analyzed. The dose of 50 mg kg^?1 soil Cu caused a toxic effect on black oat plant growth and development, affected the internal distribution of nutrients, decreased the leaf chlorophyll concentration and increased the leaf concentration of total soluble carbohydrates and starch. Increasing lime doses ameliorated the toxic effects of Cu.  相似文献   

Investigating the impact of innate dexterity skills and visuospatial aptitude on the performance of baseline laparoscopic skills in veterinary students          下载免费PDF全文

Mathew R. A. MacCormick  Jessica J. Kilkenny MSc  Meagan Walker BSc  Alex zur Linden DVM  DACVR  Ameet Singh DVM  DVSc  DACVS 《Veterinary surgery : VS》2017,46(8):1175-1186

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Evidence for a collective intelligence factor in the performance of human groups   总被引：2，自引：0，他引：2  

Woolley AW  Chabris CF  Pentland A  Hashmi N  Malone TW 《Science (New York, N.Y.)》2010,330(6004):686-688

Psychologists have repeatedly shown that a single statistical factor--often called "general intelligence"--emerges from the correlations among people's performance on a wide variety of cognitive tasks. But no one has systematically examined whether a similar kind of "collective intelligence" exists for groups of people. In two studies with 699 people, working in groups of two to five, we find converging evidence of a general collective intelligence factor that explains a group's performance on a wide variety of tasks. This "c factor" is not strongly correlated with the average or maximum individual intelligence of group members but is correlated with the average social sensitivity of group members, the equality in distribution of conversational turn-taking, and the proportion of females in the group.  相似文献   

Virulence-associated trimeric autotransporters of Haemophilus parasuis are antigenic proteins expressed in vivo   总被引：1，自引：0，他引：1  

Alex Olvera  Sonia Pina  Marta P��rez-Sim��  Simone Oliveira    Albert Bensaid 《Veterinary research》2010,41(3)

Glässer’s disease is a re-emerging swine disease characterized by a severe septicaemia. Vaccination has been widely used to control the disease, although there is a lack of extended cross-protection. Trimeric autotransporters, a family of surface exposed proteins implicated in host-pathogen interactions, are good vaccine candidates. Members of this family have been described in Haemophilus parasuis and designated as virulence-associated trimeric autotransporters (VtaA). In this work, we produced 15 recombinant VtaA passenger domains and looked for the presence of antibodies directed against them in immune sera by immunoblotting. After infection with a subclinical dose of H. parasuis Nagasaki, an IgG mediated antibody response against 6 (VtaA1, 5, 6, 8, 9 and 10) of the 13 VtaA of the Nagasaki strain was detected, indicating that they are expressed in vivo. IgA production against VtaA was detected in only one animal. VtaA were more likely to be late antigens when compared to early (Omp P5 and Omp P6) and late (YaeT) defined antigens. Antibody cross-reaction with two orthologs of Nagasaki’s VtaA5 and 6, VtaA15 and 16 of strain HP1319, was also detected. No antibodies against VtaA were detected in the sera of animals immunized with a bacterin of the Nagasaki strain, suggesting poor expression in the in vitro conditions used. Taken together, these results indicate that VtaA are good candidate immunogens that could be used to improve H. parasuis vaccines. However, their capacity to confer protective immunity needs to be further studied.  相似文献   

Plasma protein electrophoresis of Trachemys scripta and Iguana iguana     

Mercè Giménez  Yolanda Saco  Raquel Pato  Alex Busquets  Jaime M. Martorell  Anna Bassols 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2010,39(2):227-235

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Motor laterality in 4 breeds of dog     

Paul D. McGreevy  Alex Brueckner  Peter C. Thomson  Nicholas J. Branson 《Journal of Veterinary Behavior: Clinical Applications and Research》2010,5(6):318-323

The aim of the current study was designed to explore possible breed differences in a basic behavioral phenotype in dogs. It measured paw use during food-retrieval from a cylindrical, hollow, rubber toy to assess motor laterality (pawedness) in 4 breeds of dogs selected for their morphological differences: 45 greyhounds (males n = 23/females n = 22), 47 whippets (15/32), 46 pugs (15/31), and 45 boxers (17/28). A laterality index was calculated from the use of individual paws to restrain the toy during feeding. An association was found between sex and the laterality index (P = 0.035), reflecting a significant bias for left-paw use by entire male dogs and right-paw use by entire female dogs but no sex difference was found in the mean strength of laterality. No significant association was found between age and the laterality index. No breed difference was found in the laterality index (P = 0.423) or the absolute strength of laterality (i.e., the laterality index without direction, P = 0.259). However, important breed differences in the use of the test device emerged. The frequency of simultaneous use of both paws was lowest in pugs (P < 0.0001). In addition, both brachycephalic breeds (pugs and boxers) took less time than the dolichocephalic breeds (the whippets and greyhounds) to complete the criteria of 100 paw-use scores that was set for the laterality test. The absence of breed differences in the laterality index for paw use suggests that the task is a reliable measure of motor laterality in dogs during a food-retrieval task.  相似文献   

Original Study: Comparison of three intraosseous access techniques in cats     

Alex Bukoski PhD  DVM  Matthew Winter DVM  DACVR  Carsten Bandt DVM  DACVECC  Mary Wilson RT  CV  MR  CT  Andre Shih DVM  DACVA 《Journal of Veterinary Emergency and Critical Care》2010,20(4):393-397

Objective – To compare the placement feasibility and amount of bone trauma induced by 3 intraosseous (IO) access techniques in cats: an automatic impact penetration device (A), an automatic rotary insertion device (B), and a manual IO needle (C). Design – Prospective ex vivo study. Setting – University. Animals – Eighteen adult mixed breed feline cadavers. Interventions – Cadavers provided 72 total IO insertion locations divided equally between the right and left humerus and tibia. The 3 IO techniques were randomly allocated to these locations. Time to successful insertion, ease of insertion, and success rate were recorded. Each insertion site was analyzed for the number of bone fragments and defect diameter by computed tomography. Measurements and Main Results – Device B had lower time of insertion (P=0.01) compared with devices A and C. Device B had better ease of insertion scores (P<0.01) compared with devices A and C. No differences were detected between insertion sites (tibia versus humerus). No differences in the number of bone fragments, defect diameter, or success rate were detected among devices (P=0.06, 0.31, and 0.14, respectively). Conclusions – All 3 IO access methods evaluated yield acceptable results. Device B is significantly faster and easier to place in cat cadavers when compared with other methods.  相似文献   

Willingness of residents to pay and motives for conservation of urban green spaces in the compact city of Hong Kong     

Alex Y. Lo  C.Y. Jim 《Urban Forestry & Urban Greening》2010,9(2):113-120

People attach multiple values to urban green spaces which play varied roles in cities. Properly designed monetary valuation surveys can ascertain their non-market value and underlying motives. This study investigates Hong Kong residents’ recreational use of urban green spaces and assesses the monetary value of these areas. A total of 495 urban residents from different neighbourhoods and socio-economic groups were interviewed. About 70% of the respondents visited urban green spaces at least weekly. Major companions during patronage were family members and then children. Exercises and clean air topped the list of visit purposes. The recreational pattern is associated with the cramped private living condition that pushes people to public open areas which are construed as extension of home space. The valuation question solicited overwhelming support, with over 80% of the respondents willing to pay to recover a possible loss of urban green spaces area by 20%. It yielded a monthly average payment of HK$77.43 (approx. 9.90 USD) per household for five years. Non-instrumental aspects played some role in the respondents’ bidding decision. The findings could assist green space planning and nature conservation, and hinted the need to consider the pluralistic community views and expectations in relevant public policies.  相似文献   

Enhance knowledge on sustainable use of plant protection products within the framework of the Sustainable Use Directive     

Maura Calliera  Fabio Berta  Tiziano Galassi  Floriano Mazzini  Rossana Rossi  Roberto Bassi  Pierluigi Meriggi  Alfredo Bernard  Alex Marchis  Andrea Di Guardo  Ettore Capri 《Pest management science》2013,69(8):883-888

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