Factors affecting the early survival and growth of native tree seedlings planted on a degraded hillside Grassland in Hong Kong, China

The effects of seasonal drought, belowground competition, and low soil fertility on the survival and growth over 2 years of four native tree species planted on a degraded hillside grassland in Hong Kong were studied in a field transplant experiment using three-way analysis of variance. The tree species were Schima superba (Theaceae), Castanopsis fissa (Fagaceae), Schefflera heptaphylla (Araliaceae), and Sapium discolor (Euphorbiaceae), and the treatments were dry season irrigation, herbicide, and fertilizer. Each species responded differently to the treatments. Sapium had a very low survival rate as a result of wind damage at the exposed study site. All three treatments significantly reduced the survival rate of Castanopsis seedlings, whereas herbicide reduced it for Sapium but increased it for Schefflera. The significant effects on seedling growth were all positive, except for a strong negative effect of herbicide on Castanopsis growth. Overall, the results suggest that all three factors- seasonal drought, belowground competition, and low soil nutrients-can significantly impair seedling growth on a degraded hillside site in Hong Kong but that their relative importance differs among species. The growth benefits of the three treatments were largest and most consistent for Schima, which as a mature forest dominant would be expected to be particularly sensitive to the environmental conditions on degraded open sites. This study highlights the fact that more systematic planting trials are needed to identify suitable native tree species for cost-effective reforestation on degraded hillsides in Hong Kong and South China.postprin

Seed rain into upland plant communities in Hong Kong, China

Hong Kong is an extreme example of tropical landscape degradation, with no substantial remnants of the original forest cover and a highly impoverished disperser fauna. Seed availability is a potential limiting factor in vegetation recovery in such landscapes. To assess the quantity and quality of the seed rain of woody taxa, seed traps were placed in the major upland vegetation types: fire-maintained grassland, shrubland, and secondary forest. Within the grassland site, traps were placed under isolated trees, isolated male and female shrubs of Eurya chinensis, and in the open. Seeds were collected every 2 weeks for 2 years. The seed rain was highest under female shrubs in grassland (6455 seeds m -2 year -1), where it was almost entirely confined to their fruiting period. Next highest were isolated trees (890 seeds), followed by male isolated shrubs (611 seeds), shrubland (558 seeds), forest (129 seeds) and open grassland (47 seeds). The number of seed taxa was highest in shrubland (59), followed by isolated trees (42), forest (42), female isolated shrubs (28), male isolated shrubs (15), and open grassland (9). The seed rain differed in species composition between the forest, shrubland, and grassland sites, while the differences within the grassland site were largely in terms of quantity. Birds (particularly bulbuls, Pycnonotus spp.) are known or inferred to be the major dispersal agents for 85% of the seed taxa trapped, 99% of the total number of seeds trapped, and 99.8% of the seeds trapped in the grassland site. Few taxa and <1\% of the total seeds were dispersed by wind and no seed taxa were definitely dispersed by fruit bats. The results suggest that even in the most degraded landscape the seed rain is adequate for the development of woody vegetation cover, but that human intervention will be needed for the restoration of plant diversity. © Springer 2006.postprin

Natural regeneration in exotic tree plantations in Hong Kong, China

Tree plantations consisting mostly of a single exotic species have been established in Hong Kong, South China, for reforesting degraded lands since the 1950s. In this study, natural woody plant regeneration success under different types of closed-canopy plantations (Acacia confusa, Lophostemon confertus, Melaleuca quinquenervia and mixed-plantings) and natural secondary forests in the central New Territories were assessed. A total of 79 tree species, 64 shrubs and 23 woody climbers were recorded in 16 20 m × 20 m plantation plots. Stem density of woody plant regeneration was similar among all sites, ranging from 9031 to 10,950 stems > 0.5 m in height per hectare. Multivariate analysis of understorey species composition showed that there were consistent differences between plantation types. Lophostemon plantations generally had poor native plant colonization in comparison with natural secondary forests and other types of plantations. These differences between forest types can be at least partly attributed to pre-existing site conditions, since the tree species planted were matched to the site. Native woody plant colonization was poor on sites isolated from natural seed sources. Plantation understories were generally dominated by a few species of bird-dispersed shrubs, suggesting that enrichment planting with poorly dispersed shade-tolerant native tree species will be needed to facilitate regeneration in those plantations where natural regeneration is inadequate. © 2005 Elsevier B.V. All rights reserved.postprin

Splenic infarction: an update on William Osler\u27s observations.

BACKGROUND: Osler taught that splenic infarction presents with left upper abdominal quadrant pain, tenderness and swelling accompanied by a peritoneal friction rub. Splenic infarction is classically associated with bacterial endocarditis and sickle cell disease. OBJECTIVES: To describe the contemporary experience of splenic infarction. METHODS: We conducted a chart review of inpatients diagnosed with splenic infarction in a Jerusalem hospital between 1990 and 2003. RESULTS: We identified 26 cases with a mean age of 52 years. Common causes were hematologic malignancy (six cases) and intracardiac thrombus (five cases). Only three cases were associated with bacterial endocarditis. In 21 cases the splenic infarction brought a previously undiagnosed underlying disease to attention. Only half the subjects complained of localized left-sided abdominal pain, 36% had left-sided abdominal tenderness; 31% had no signs or symptoms localized to the splenic area, 36% had fever, 56% had leukocytosis and 71% had elevated lactate dehydrogenase levels. One splenectomy was performed and all patients survived to discharge. A post hoc analysis demonstrated that single infarcts were more likely to be associated with fever (20% vs. 63%, p \u3c 0.05) and leukocytosis (75% vs. 33%, P = 0.06) CONCLUSIONS: The clinical presentation of splenic infarction in the modern era differs greatly from the classical teaching, regarding etiology, signs and symptoms. In patients with unexplained splenic infarction, investigation frequently uncovers a new underlying diagnosis

Managing amphibians in agricultural wetlands in South China: effects of fertilizers on Tadpole Performance

Abstract no. 0192 SSAR Siebert Conservation Award, Session IpostprintThe 2011 Joint Meeting of Ichthyologists and Herpetologists, Minneapolis, MN., 6-11 July 2011

Correction: Splice site identification using probabilistic parameters and SVM classification

BACKGROUND: Recent advances and automation in DNA sequencing technology has created a vast amount of DNA sequence data. This increasing growth of sequence data demands better and efficient analysis methods. Identifying genes in this newly accumulated data is an important issue in bioinformatics, and it requires the prediction of the complete gene structure. Accurate identification of splice sites in DNA sequences plays one of the central roles of gene structural prediction in eukaryotes. Effective detection of splice sites requires the knowledge of characteristics, dependencies, and relationship of nucleotides in the splice site surrounding region. A higher-order Markov model is generally regarded as a useful technique for modeling higher-order dependencies. However, their implementation requires estimating a large number of parameters, which is computationally expensive. RESULTS: The proposed method for splice site detection consists of two stages: a first order Markov model (MM1) is used in the first stage and a support vector machine (SVM) with polynomial kernel is used in the second stage. The MM1 serves as a pre-processing step for the SVM and takes DNA sequences as its input. It models the compositional features and dependencies of nucleotides in terms of probabilistic parameters around splice site regions. The probabilistic parameters are then fed into the SVM, which combines them nonlinearly to predict splice sites. When the proposed MM1-SVM model is compared with other existing standard splice site detection methods, it shows a superior performance in all the cases. CONCLUSION: We proposed an effective pre-processing scheme for the SVM and applied it for the identification of splice sites. This is a simple yet effective splice site detection method, which shows a better classification accuracy and computational speed than some other more complex methods

The Role of Core Clerkship Procedural Experience in the Specialty Decision Making Process of Fourth Year Medical Students.

Background: The 3rd year of medical school is the most influential year in a student\u27s specialty decision making process. We aim to identify the key features of 3rd year clerkships that influenced specialty decision making and compare the clerkship and procedural experiences between students choosing surgical-based residencies (SBR) and non-surgical-based residencies (NSBR). Methods: A single institution electronic survey was conducted of medical students who have completed all third-year clerkships. Results: Sixty medical students responded (response rate 41%): 23 were interested in an SBR. Differences in clerkship experiences were noted between the SBR and NSBR groups regarding type of cases (p = 0.0347), work hours (p = 0.0205), opportunities for procedures (p = 0.0004). No significant difference was noted in volume of procedures perform during clerkships. The SBR group felt procedural skill development was more important before residency (p = 0.0048). Conclusions: There is notable differences between SBR and NSBR students in terms of what parts of the 3rd year clerkships influence their career decision. The amount of procedures performed during clerkships did not correlate with students that choose a SBR or NSBR

Achieving Population Health: What Evidence Will We Need?

This forum presentation focuses on the growing importance of adopting a population health approach to national health policy. Dr. Simpson reviews current federal policies promoting population health and describes state, community, and systems innovations. Presentation: 49 minutes (audio only) PowerPoint slides appear below

Impacts of illegal trapping on endangered big-headed turtles (Platysternon megacephalum) in Hong Kong

Abstract no. 0178 SSAR Seibert Conservation Award, Session IIpostprintThe 2011 Joint Meeting of Ichthyologists and Herpetologists, Minneapolis, MN., 6-11 July 2011