Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Sugarcane genes associated with sucrose content

<p>Abstract</p> <p>Background -</p> <p>Sucrose content is a highly desirable trait in sugarcane as the worldwide demand for cost-effective biofuels surges. Sugarcane cultivars differ in their capacity to accumulate sucrose and breeding programs routinely perform crosses to identify genotypes able to produce more sucrose. Sucrose content in the mature internodes reach around 20% of the culms dry weight. Genotypes in the populations reflect their genetic program and may display contrasting growth, development, and physiology, all of which affect carbohydrate metabolism. Few studies have profiled gene expression related to sugarcane's sugar content. The identification of signal transduction components and transcription factors that might regulate sugar accumulation is highly desirable if we are to improve this characteristic of sugarcane plants.</p> <p>Results -</p> <p>We have evaluated thirty genotypes that have different Brix (sugar) levels and identified genes differentially expressed in internodes using cDNA microarrays. These genes were compared to existing gene expression data for sugarcane plants subjected to diverse stress and hormone treatments. The comparisons revealed a strong overlap between the drought and sucrose-content datasets and a limited overlap with ABA signaling. Genes associated with sucrose content were extensively validated by qRT-PCR, which highlighted several protein kinases and transcription factors that are likely to be regulators of sucrose accumulation. The data also indicate that aquaporins, as well as lignin biosynthesis and cell wall metabolism genes, are strongly related to sucrose accumulation. Moreover, sucrose-associated genes were shown to be directly responsive to short term sucrose stimuli, confirming their role in sugar-related pathways.</p> <p>Conclusion -</p> <p>Gene expression analysis of sugarcane populations contrasting for sucrose content indicated a possible overlap with drought and cell wall metabolism processes and suggested signaling and transcriptional regulators to be used as molecular markers in breeding programs. Transgenic research is necessary to further clarify the role of the genes and define targets useful for sugarcane improvement programs based on transgenic plants.</p

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Fatores de risco de complicações pulmonares em pacientes com sarcoma após toracotomia para a ressecção de nódulos pulmonares Risk factors for pulmonary complications in patients with sarcoma after the resection of pulmonary nodules by thoracotomy

OBJETIVO: Identificar os fatores de risco para complicações pulmonares em pacientes com sarcoma após serem submetidos a toracotomia para a ressecção de nódulos pulmonares. MÉTODOS: Estudo de coorte retrospectivo com 68 pacientes consecutivos com diagnóstico de sarcomas e submetidos a 174 toracotomias para a ressecção de nódulos pulmonares. A variável dependente foi definida como a ocorrência de qualquer complicação pulmonar pós-operatória. As variáveis independentes foram relacionadas com o paciente, o diagnóstico de base e o tipo de procedimento cirúrgico. Os dados foram analisados segundo um modelo multivariado de estimação de equações generalizadas, com uma função de ligação logística e uma estrutura de correlação simétrica. RESULTADOS: Houve 24 complicações (13,8%; IC95%: 9,0-19,8), incluindo um óbito. Os pacientes que apresentaram complicações pós-operatórias tiveram um tempo médio de internação duas vezes superior àqueles sem complicações (18,8 ± 10,0 dias vs. 8,6 ± 6,0 dias; p < 0,05). As variáveis que se correlacionaram com o desfecho foram o tipo de ressecção (em cunha ou anatômica; OR = 3,6; IC95%: 1,5-8,8), necessidade de transfusão sanguínea (OR = 9,8; IC95%: 1,6-60,1) e número de nódulos ressecados (OR = 1,1; IC95%: 1,0-1,1). O modelo multivariado obtido exibiu uma área sob a curva ROC de 0,75 (IC95%: 0,65-0,85). CONCLUSÕES: As complicações pulmonares pós-operatórias após a ressecção de nódulos pulmonares em pacientes com sarcoma não foram raras, ocorrendo em cerca de 10% dos procedimentos. A ocorrência dessas complicações pode ser antecipada pelo uso de ressecção não em cunha, necessidade de hemotransfusão e maior número de nódulos ressecados. Assim, já no pós-operatório imediato, é possível identificar pacientes de risco, que devem ser estritamente monitorizados durante o período pós-operatório imediato. Para esses pacientes, todas as medidas preventivas devem ser tomadas.<br>OBJECTIVE: To identify the risk factors for pulmonary complications after thoracotomy for the resection of pulmonary nodules in patients with sarcoma. METHODS: A retrospective cohort study involving 68 consecutive patients diagnosed with sarcoma and submitted to a total of 174 thoracotomies for the resection of pulmonary nodules. The dependent variable was defined as the occurrence of any postoperative pulmonary complications. The independent variables were related to the patient, underlying diagnosis, and type of surgical procedure. We analyzed the data using a multivariate generalized estimating equations model with logistic link function and a symmetric correlation structure. RESULTS: Complications were observed in 24 patients (13.8%, 95% CI: 9.0-19.8), and there was one death. The mean length of hospital stay was twice as long in the patients with postoperative complications as in those without (18.8 ± 10.0 days vs. 8.6 ± 6.0 days; p < 0.05). The variables that correlated with the outcome measure were the type of resection (wedge vs. anatomic; OR = 3.6; 95% CI: 1.5-8.8), the need for blood transfusion (OR = 9.8; 95% CI: 1.6-60.1), and the number of nodules resected (OR = 1.1; 95% CI: 1.0-1.1). The multivariate model showed an area under the ROC curve of 0.75 (95% CI: 0.65-0.85). CONCLUSIONS: Postoperative pulmonary complications were common after pulmonary nodule resection in patients with sarcoma, occurring in approximately 10% of the procedures. The occurrence of such complications can be expected when techniques other than wedge resection are employed, when blood transfusion is required, and when a great number of nodules are resected. Therefore, it is possible to identify patients at risk for pulmonary complications, who should be closely monitored in the immediate postoperative period. In such patients, all preventive measures should be taken