How far do birds disperse seeds in the degraded tropical landscape of Hong Kong,China?     

Jacqueline E. S. Weir  Richard T. Corlett 《Landscape Ecology》2007,22(1):131-140

Information on seed dispersal distances is critical for understanding plant species persistence in habitat fragments and vegetation recovery when disturbance is reduced. In the degraded upland landscape of Hong Kong (22°N), the bulbuls Pycnonotus sinensis and P. jocosus are responsible for a large proportion of seed movements. Dispersal distances were estimated from gut passage times (GPTs) and movement patterns determined by radio-telemetry. Estimates were also made for the hwamei, Garrulax canorus. Seven adult P. sinensis and four adult G. canorus were tracked in winter, and six juvenile P. sinensis, three juvenile P. jocosus and two juvenile G. canorus in summer. GPTs were 5–122 min in the bulbuls and 18–61 min in the hwamei. Most 10-min movements were <100 m for the bulbuls and <50 m for the hwamei, but the largest were >1300 m for both bulbuls and 940 m for the hwamei. Displacement-time graphs generally levelled off rapidly, with median displacements <60 m after an hour, except with summer juvenile bulbuls. Median displacements during median gut passage times for seeds from single-seeded fruits were 40, 116 and 131 m, respectively, for winter adult P. sinensis and summer juvenile P. sinensis and P. jocosus. Maximum observed displacements during the maximum measured GPTs were >1 km for all bulbuls. Estimated dispersal distances were shorter for hwameis. The radio-telemetry results were supplemented by 49 h of visual observations, during which 1,510 bird movements across open areas were observed, 64% by P. sinensis, 13% by P. jocosus, and 0.5% by G. canorus. The bulbuls, therefore, connect habitat fragments in upland Hong Kong for plants with fruits within their maximum gape width.  相似文献   

Keratouveitis in juvenile dogs and its presumed association with canine adenovirus infection     

Hannah Joyce  James A. C. Oliver  Georgina Fricker  Willie Weir  Lorraine Fleming 《Veterinary ophthalmology》2023,26(3):262-267

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Effects of FGF10 on Bovine Oocyte Meiosis Progression,Apoptosis, Embryo Development and Relative Abundance of Developmentally Important Genes In Vitro          下载免费PDF全文

RF Pomini Pinto  PK Fontes  B Loureiro  AC Sousa Castilho  J Sousa Ticianelli  E Montanari Razza  RA Satrapa  J Buratini  C Moraes Barros 《Reproduction in domestic animals》2015,50(1):84-90

Fibroblast growth factor (FGF10) acts at the cumulus oocyte complex, increasing the expression of cumulus cell expansion‐related genes and oocyte competency genes. We tested the hypothesis that addition of FGF10 to the maturation medium improves oocyte maturation, decreases the percentage of apoptotic oocytes and increases development to the blastocyst stage while increasing the relative abundance of developmentally important genes (COX2, CDX2 and PLAC8). In all experiments, oocytes were matured for 22 h in TCM‐199 supplemented with 0, 2.5, 10 or 50 ng/ml FGF10. In Experiment 1, after maturation, oocytes were stained with Hoechst to evaluate meiosis progression (metaphase I, intermediary phases and extrusion of the first polar body) and submitted to the TUNEL assay to evaluate apoptosis. In Experiment 2, oocytes were fertilized and cultured to the blastocyst stage. Blastocysts were frozen for analysis of COX2, CDX2 and PLAC8 relative abundance. In Experiment 1, 2.5 ng/ml FGF10 increased (p < 0.05) the percentage of oocytes with extrusion of the first polar body (35%) compared to 0, 10 and 50 ng/ml FGF10 (21, 14 and 12%, respectively) and FGF10 decreased the percentage of oocytes that were TUNEL positive in all doses studied. In Experiment 2, there was no difference in the percentage of oocytes becoming blastocysts between treatments and control. Real‐time RT‐PCR showed a tendency of 50 ng/ml FGF10 to increase the relative abundance of COX2 and PLAC8 and of 10 ng/ml FGF10 to increase CDX2. In conclusion, the addition of FGF10 to the oocyte maturation medium improves oocyte maturation in vitro, decreases the percentage of apoptotic oocytes and tends to increase the relative abundance of developmentally important genes.  相似文献   

Phytophthora agathidicida: research progress,cultural perspectives and knowledge gaps in the control and management of kauri dieback in New Zealand     

R. E. Bradshaw  S. E. Bellgard  A. Black  B. R. Burns  M. L. Gerth  R. L. McDougal  P. M. Scott  N. W. Waipara  B. S. Weir  N. M. Williams  R. C. Winkworth  T. Ashcroft  E. L. Bradley  P. P. Dijkwel  Y. Guo  R. F. Lacey  C. H. Mesarich  P. Panda  I. J. Horner 《Plant pathology》2020,69(1):3-16

Kauri (Agathis australis), which is one of the world's largest and longest-living conifer species, is under threat from a root and collar dieback disease caused by the oomycete pathogen Phytophthora agathidicida. The noted incidence of kauri dieback has increased in the past decade, and even trees >1000 years old are not immune. This disease has profound effects on both forest ecosystems and human society, particularly indigenous Māori, for whom kauri is a taonga or treasure of immense significance. This review brings together existing scientific knowledge about the pathogen and the devastating disease it causes, as well as highlighting important knowledge gaps and potential approaches for disease management. The life cycle of P. agathidicida is similar to those of other soilborne Phytophthora pathogens, with roles for vegetative hyphae, zoospores and oospores in the disease. However, there is comparatively little known about many aspects of the biology of P. agathidicida, such as its host range and disease latency, or about the impact on the disease of abiotic and biotic factors such as soil health and co-occurring Phytophthora species. This review discusses current and emerging tools and strategies for surveillance, diagnostics and management, including a consideration of genomic resources, and the role these play in understanding the pathogen and how it causes this deadly disease. Key aspects of indigenous Māori knowledge, which include rich ecological and historical knowledge of kauri forests and a holistic approach to forest health, are highlighted.  相似文献   

A REVIEW OF PORTAL SCREEN-FILM TECHNOLOGY AND FIVE RADIOLOGISTS' EVALUATIONS OF SOME EXISTING PRODUCTS     

Michael A.  Walker  DVM  Daniel N.  Steinheimer  DVM  Vicki A.  Weir  RTS  Linda D.  Homco  DVM  Ronald W.  Green  DVM  Earl L.  Morris  DVM  Margo E.  Hess 《Veterinary radiology & ultrasound》1999,40(3):318-322

Portal radiographs, radiographs made to document the accuracy of radiotherapy treatment fields, are typically of poor image contrast. Recently, a new portal film and screened-cassette system was marketed, the Kodak EC-L system, with the claim of greatly improved image contrast. This new EC-L system was tested on a canine cadaver exposed to Cobalt-60 teletherapy gamma radiation, and image quality was compared to earlier marketed Kodak portal film products. The EC-L system was found to provide portal images of improved contrast/quality.  相似文献   

A dose titration study into the effects of diazepam or midazolam on the propofol dose requirements for induction of general anaesthesia in client owned dogs,premedicated with methadone and acepromazine     

Rebecca Robinson  Kate Borer‐Weir 《Veterinary anaesthesia and analgesia》2013,40(5):455-463

ObjectiveTo assess the effect of a benzodiazepine co–induction on propofol dose requirement for induction of anaesthesia in healthy dogs, to describe any differences between midazolam and diazepam and to determine an optimal benzodiazepine dose for co–induction.Study designProspective, randomised, blinded placebo controlled clinical trial.AnimalsNinety client owned dogs (ASA I–III, median body mass 21.5kg (IQR 10–33)) presented for anaesthesia for a variety of procedures.MethodsDogs were randomised to receive saline 0.1 mL kg^?1, midazolam or diazepam at 0.2, 0.3, 0.4 or 0.5 mg kg^?1. All dogs received 0.01 mg kg^?1 acepromazine and 0.2 mg kg^?1 methadone intravenously (IV). Fifteen minutes later, sedation was assessed and scored prior to anaesthetic induction. Propofol, 1 mg kg^?1, was administered IV, followed by the treatment drug. Further propofol was administered until endotracheal intubation was possible. Recorded data included patient signalment, sedation score, propofol dosage and any adverse reactions.ResultsMidazolam (all groups combined) significantly reduced propofol dose requirement compared to saline (p < 0.001) and diazepam (p = 0.008). Midazolam (0.4 mg kg^?1) significantly reduced propofol dose requirement (p = 0.014) compared to saline, however other doses failed to reach statistical significance. Diazepam did not significantly reduce propofol dose requirement compared to saline (p = 0.089). Dogs weighing <5 kg, regardless of treatment group, required a greater propofol dose than those weighing 5–40 kg (p = 0.002) and those >40 kg (p = 0.008). Dogs which were profoundly sedated required less propofol than those which were mildly sedated (p < 0.001) and adequately sedated (p = 0.003).Conclusions and clinical relevanceMidazolam (0.4 mg kg^?1) given IV after 1 mg kg^?1 of propofol significantly reduced the further propofol dose required for intubation compared to saline. At the investigated doses, diazepam did not have significant propofol dose sparing effects.  相似文献   

Genome of the host-cell transforming parasite Theileria annulata compared with T. parva     

Pain A  Renauld H  Berriman M  Murphy L  Yeats CA  Weir W  Kerhornou A  Aslett M  Bishop R  Bouchier C  Cochet M  Coulson RM  Cronin A  de Villiers EP  Fraser A  Fosker N  Gardner M  Goble A  Griffiths-Jones S  Harris DE  Katzer F  Larke N  Lord A  Maser P  McKellar S  Mooney P  Morton F  Nene V  O'Neil S  Price C  Quail MA  Rabbinowitsch E  Rawlings ND  Rutter S  Saunders D  Seeger K  Shah T  Squares R  Squares S  Tivey A  Walker AR  Woodward J  Dobbelaere DA  Langsley G  Rajandream MA  McKeever D  Shiels B  Tait A  Barrell B  Hall N 《Science (New York, N.Y.)》2005,309(5731):131-133

Theileria annulata and T. parva are closely related protozoan parasites that cause lymphoproliferative diseases of cattle. We sequenced the genome of T. annulata and compared it with that of T. parva to understand the mechanisms underlying transformation and tropism. Despite high conservation of gene sequences and synteny, the analysis reveals unequally expanded gene families and species-specific genes. We also identify divergent families of putative secreted polypeptides that may reduce immune recognition, candidate regulators of host-cell transformation, and a Theileria-specific protein domain [frequently associated in Theileria (FAINT)] present in a large number of secreted proteins.  相似文献   

SOIL SCIENCE     

Weir WW  Peter AM 《Science (New York, N.Y.)》1930,71(1834):218-219

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Chaotic Dynamics in an Insect Population     

RF Costantino  RA Desharnais  JM Cushing  B Dennis 《Science (New York, N.Y.)》1997,275(5298):389-391

A nonlinear demographic model was used to predict the population dynamics of the flour beetle Tribolium under laboratory conditions and to establish the experimental protocol that would reveal chaotic behavior. With the adult mortality rate experimentally set high, the dynamics of animal abundance changed from equilibrium to quasiperiodic cycles to chaos as adult-stage recruitment rates were experimentally manipulated. These transitions in dynamics corresponded to those predicted by the mathematical model. Phase-space graphs of the data together with the deterministic model attractors provide convincing evidence of transitions to chaos.  相似文献   

Crystal Structure of Benzene II at 25 Kilobars     

Piermarini GJ  Mighell AD  Weir CE  Block S 《Science (New York, N.Y.)》1969,165(3899):1250-1255

Crystals of a high-pressure form of benzene (benzene 11) were grown in the diamond-anvil pressure cell at elevated temperature and pressure from the transition of solid I to solid II. X-ray precession data were obtained from a single-crystal in the high-pressure cell. At 21 degrees C and about 25 kilobars, benzene II crystallizes in the monoclinic system with a = 5.417 +/- 0.005 angstroms (S.D.), b = 5.376 +/- 0.019 angstroms, c = 7.532 +/- 0.007 angstroms, beta = 110.00 degrees +/- 0.08 degrees , space group P2(1)/ c, Pc= 1.26 grams per cubic centimeter. The crystal structure was solved by generating all possible molecular packing configurations and calculating structure factors, reliability factors, and packing energies for each configuration. This procedure produced a unique solution for the molecular packing of benzene II.  相似文献