TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Effect of vertebroplasty on the compressive strength of vertebral bodies

Background context Percutaneous vertebroplasty has been used successfully for many years in the treatment of painful compressive vertebral fractures due to osteoporosis. Purpose To compare the effect of vertebroplasty on the compressive strength of unfractured vertebral bodies. Study design Biomechanical study on cadaveric thoracic vertebrae. Methods Forty vertebral bodies from four cadaveric thoracic spines were used for this experiment. Before testing, each thoracic spine was submitted to bone density testing and radiographic evaluation to rule out any obvious fractures. Under image intensification, 6 mL of a mixture of polymethylmethacrylate (PMMA) with barium (8 g of barium/40 g of PMMA) was injected into every other vertebral body of each spine specimen. After vertebroplasty, all soft tissues were dissected from the spine, and the vertebral bodies were separated and potted for mechanical testing. Testing to failure was performed using a combination of axial compression and anterior flexion moments. Two pneumatic cylinders applied anterior and posterior loads at a distance ratio of 4:3 relative to the anterior vertebral body wall, whereas two additional cylinders applied lateral loads, each at a constant rate of 200 N/s. Results The average failure loads for nonvertebroplasty specimens was 6724.02±3291.70 N, whereas the specimens injected with PMMA failed at an average compressive force of 5770.50±2133.72 N. No statistically significant difference in failure loads could be detected between intact specimens and those that had undergone vertebroplasty. Conclusions Under these specific loading conditions, no significant increase in compressive strength of the vertebral bodies could be documented. This suggests that some caution should be applied to the concept of "prophylactic" vertebroplasty in patients at risk for fracture

From local to global patterns: Evaluation issues in rule learning algorithms

Separate-and-conquer or covering rule learning algorithms may be viewed as a technique for using local pattern discovery for generating a global theory. Local patterns are learned one at a time, and each pattern is evaluated in a local context, with respect to the number of positive and negative examples that it covers. Global context is provided by removing the examples that are covered by previous patterns before learning a new rule. In this paper, we discuss several research issues that arise in this context. We start with a brief discussion of covering algorithms, their problems, and review a few suggestions for resolving them. We then discuss the suitability of a well-known family of evaluation metrics, and analyze how they trade off coverage and precision of a rule. Our conclusion is that in many applications, coverage is only needed for establishing statistical significance, and precision is the metric that should be optimized for rules. The main problem with optimizing precision is its unreliability for low example sizes, which is mainly caused by overfitting. We then report some preliminary experiments that addresses this problem by meta-learning a predictor for the true accuracy of a rule based on its coverage on the training set

Análise comparativa da resistência de fêmures de cães após a confecção de janelas ósseas circular e quadrada Comparative analysis of dog femur resistance after receiving circular and square holes

Com o objetivo de avaliar o enfraquecimento causado pela confecção de janela óssea cortical, os autores confeccionaram uma janela circular no osso cortical da diáfise de oito fêmures de carcaças de cães e uma janela quadrada nos oito pares destes fêmures, com diagonal semelhante ao diâmetro da janela circular contralateral. As peças anatômicas foram submetidas a teste de tensão torcional em uma máquina de ensaios mecânicos; obtendo-se o torque máximo e a rigidez à torção. Os resultados mostraram que, para o fêmur com janela circular, o torque máximo médio foi de 13,65 ± 5,12 Nm, e a rigidez média foi de 1,18 ± 0,45 Nm/grau, enquanto que para a janela quadrada o torque máximo médio foi de 13, 39 ± 5,23 Nm, e a rigidez média foi de 1,05 ± 0,41 Nm/grau. A resistência nos ossos com janela circular e quadrada submetidos à tensão torcional foi praticamente igual, fato este corroborado pela análise estatística que não revelou diferença significante (p = 0,05).<br>With the purpose of evaluating the weakness caused by holes in the cortical bone, the authors performed circular holes in the diaphysis cortical bone of eight femurs from dog carcasses, and square holes in the diaphysis cortical bone of the contralateral femurs, the diagonals being similar to the diameters. The specimens were submitted to torsion stress test in a mechanical test machine to determine maximum torque and rigidity to torsion. Maximum mean torque for the femurs with circular holes was 13.65 ± 5.12 Nm and mean rigidity was 1.18 ± 0.45 Nm/degree, while the femurs with square holes showed maximum mean torque of 13.39 ± 5.23 Nm and mean rigidity of 1.05 ± 0.41 Nm/degree. The resistance to torsion stress in femurs with circular or square holes was very similar and the statistical analysis did not show a significant difference (p = 0.05)