Evolutionary diversity is associated with wood productivity in Amazonian forests

Higher levels of taxonomic and evolutionary diversity are expected to maximize ecosystem function, yet their relative importance in driving variation in ecosystem function at large scales in diverse forests is unknown. Using 90 inventory plots across intact, lowland, terra firme, Amazonian forests and a new phylogeny including 526 angiosperm genera, we investigated the association between taxonomic and evolutionary metrics of diversity and two key measures of ecosystem function: aboveground wood productivity and biomass storage. While taxonomic and phylogenetic diversity were not important predictors of variation in biomass, both emerged as independent predictors of wood productivity. Amazon forests that contain greater evolutionary diversity and a higher proportion of rare species have higher productivity. While climatic and edaphic variables are together the strongest predictors of productivity, our results show that the evolutionary diversity of tree species in diverse forest stands also influences productivity. As our models accounted for wood density and tree size, they also suggest that additional, unstudied, evolutionarily correlated traits have significant effects on ecosystem function in tropical forests. Overall, our pan-Amazonian analysis shows that greater phylogenetic diversity translates into higher levels of ecosystem function: tropical forest communities with more distantly related taxa have greater wood productivity.

An architectural understanding of natural sway frequencies in trees

The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests.

Improved allometric models to estimate the aboveground biomass of tropical trees

Terrestrial carbon stock mapping is important for the successful implementation of climate change mitigation policies. Its accuracy depends on the availability of reliable allometric models to infer oven-dry aboveground biomass of trees from census data. The degree of uncertainty associated with previously published pantropical aboveground biomass allometries is large. We analyzed a global database of directly harvested trees at 58 sites, spanning a wide range of climatic conditions and vegetation types (4004 trees ≥ 5 cm trunk diameter). When trunk diameter, total tree height, and wood specific gravity were included in the aboveground biomass model as covariates, a single model was found to hold across tropical vegetation types, with no detectable effect of region or environmental factors. The mean percent bias and variance of this model was only slightly higher than that of locally fitted models. Wood specific gravity was an important predictor of aboveground biomass, especially when including a much broader range of vegetation types than previous studies. The generic tree diameter-height relationship depended linearly on a bioclimatic stress variable E, which compounds indices of temperature variability, precipitation variability, and drought intensity. For cases in which total tree height is unavailable for aboveground biomass estimation, a pantropical model incorporating wood density, trunk diameter, and the variable E outperformed previously published models without height. However, to minimize bias, the development of locally derived diameter-height relationships is advised whenever possible. Both new allometric models should contribute to improve the accuracy of biomass assessment protocols in tropical vegetation types, and to advancing our understanding of architectural and evolutionary constraints on woody plant development.

The importance of crown dimensions to improve tropical tree biomass estimates

Tropical forests play a vital role in the global carbon cycle, but the amount of carbon they contain and its spatial distribution remain uncertain. Recent studies suggest that once tree height is accounted for in biomass calculations, in addition to diameter and wood density, carbon stock estimates are reduced in many areas. However, it is possible that larger crown sizes might offset the reduction in biomass estimates in some forests where tree heights are lower because even comparatively short trees develop large, well-lit crowns in or above the forest canopy. While current allometric models and theory focus on diameter, wood density, and height, the influence of crown size and structure has not been well studied. To test the extent to which accounting for crown parameters can improve biomass estimates, we harvested and weighed 51 trees (11-169 cm diameter) in southwestern Amazonia where no direct biomass measurements have been made. The trees in our study had nearly half of total aboveground biomass in the branches (44% +/- 2% [mean +/- SE]), demonstrating the importance of accounting for tree crowns. Consistent with our predictions, key pantropical equations that include height, but do not account for crown dimensions, underestimated the sum total biomass of all 51 trees by 11% to 14%, primarily due to substantial underestimates of many of the largest trees. In our models, including crown radius greatly improves performance and reduces error, especially for the largest trees. In addition, over the full data set, crown radius explained more variation in aboveground biomass (10.5%) than height (6.0%). Crown form is also important: Trees with a monopodial architectural type are estimated to have 21-44% less mass than trees with other growth patterns. Our analysis suggests that accounting for crown allometry would substantially improve the accuracy of tropical estimates of tree biomass and its distribution in primary and degraded forests.

The silicone gel breast implant controversy: current status and clinical implications

The silicone breast implant controversy has amassed a great deal of media coverage in the past year. Unfortunately, separating fact from fiction has been extremely frustrating and difficult, not only for physicians but for women who have either had or are considering cosmetic or reconstructive surgery of the breast. At a recent meeting attended by most of the board eligible and certified Plastic and Reconstructive Surgeons in the State of Arkansas, it was felt that a consensus statement was needed to clarify the issues and inform other Arkansas physicians of the most up to date information. The result is a fairly comprehensive review which will require your indulgence. Breast implants are placed not only by Plastic and Reconstructive Surgeons, but by Otolaryngologists, "Facial Plastic Surgeons", Obstetricians/Gynecologists, General Surgeons, Dermatologists and Family Practitioners. We believe it is the ethical and legal responsibility of the physicians who elect to perform these procedures to provide adequate care and follow-up for these patients when either real or perceived problems arise. Accurate information, reassurance and occasionally re-operations are required for many of these patients.

Systemic vasculitis following influenza vaccination--report of 3 cases and literature review

Influenza vaccination is a widely accepted practice particularly among the elderly and high risk individuals. Minor and transitory side effects following the vaccination are common while systemic complications are infrequently reported. We describe 3 patients who developed systemic vasculitis following influenza vaccination. With increasing use of influenza vaccination, attention should be drawn to the possible expression of systemic adverse effects such as vasculitis.

An aggressive return-to-work program in surgical treatment of carpal tunnel syndrome: a comparison of costs

Carpal tunnel syndrome is a common malady associated with modern manufacturing. An aggressive return-to-work program was begun in 1980. A prospective study was begun in 1982, and data matured through 1988 comparing the costs of a control group of patients treated by the more traditional method (in the author's geographic area) and the author's aggressive return-to-work policy. Sixty-seven patients with 94 carpal tunnel surgeries were studied. The results reveal that the aggressively treated group had 1 of 44 patients fail to return to work following surgery, and 3 of 23 failed to return to work from the control group. One patient of each group developed a recurrence. The tangible costs that could be computed were found to be 58 percent less in the aggressively treated group than in the control group. At the same time, the patients can maintain their standard of living.

Benign fibrous pleural tumor with elevation of insulin-like growth factor and hypoglycemia

We have reported the case of a 69-year-old woman with a hugh benign fibrous tumor of the left pleura and hypoglycemic seizures. Increased preoperative levels of insulin-like growth factor (IGF II) were present; insulin level was low and plasma levels of somatomedin C were normal. After resection of the 2,400 gm tumor, blood sugar level has remained normal, and IGF II has fallen to normal limits. This appears to be the first reported case documenting elevated serum IGF II in association with a benign fibrous pleural tumor.

Total reconstruction of a two-compartment scrotum by tissue expansion

A case report is presented showing the reconstruction of a two-compartment scrotum out of hair-bearing perineal skin following a severe degloving injury of the scrotum and testicles. We feel that this is an appropriate procedure to be used in patients who have lost the testicles and scrotum traumatically, either one or both testicles, or in the situation where both testicles have been spared. Aesthetically, the result in this patient is superior to skin grafting and should be readily reproducible.

Glyburide-induced hepatitis

Drug-induced hepatotoxicity, although common, has been reported only infrequently with sulfonylureas. For glyburide, a second-generation sulfonylurea, only two brief reports of hepatotoxicity exist. Two patients with type II diabetes mellitus developed an acute hepatitis-like syndrome soon after initiation of glyburide therapy. There was no serologic evidence of viral infection, and a liver biopsy sample showed a histologic pattern consistent with drug-induced hepatitis. Both patients recovered quickly after stopping glyburide therapy and have remained well for a follow-up period of 1 year. Glyburide can produce an acute hepatitis-like illness in some persons.

The crocodile tear syndrome

Gusto-lacrimation, or "crocodile tear syndrome," is a rare complication, with 95 cases reported in the literature. Two patients are presented here, one after a facial fracture which apparently extended into the temporal bone proximal to the optic ganglion, and one after a Bell's palsy. The mechanism appears to be a misdirection of regenerating gustatory fibers destined for the salivary glands, so that they become secretory fibers to the lacrimal gland and cause homolateral tearing while the patient is eating. A simple procedure, involving subtotal resection of the palpebral lobe of the involved lacrimal gland, proved to be an effective corrective measure in these cases. Although it was not done in these cases, it would perhaps be advisable to do a Schirmer's test to assist in determining the amount of gland to be removed.