Plant traits controlling growth change in response to a drier climate

This is the final version. Available on open access from Wiley via the DOI in this recordPlant traits are increasingly being used to improve prediction of plant function, including plant demography. However, the capability of plant traits to predict demographic rates remains uncertain, particularly in the context of trees experiencing a changing climate. Here we present data combining 17 plant traits associated with plant structure, metabolism and hydraulic status, with measurements of long-term mean, maximum and relative growth rates for 176 trees from the world’s longest running tropical forest drought experiment. We demonstrate that plant traits can predict mean annual tree growth rates with moderate explanatory power. However, only combinations of traits associated more directly with plant functional processes, rather than more commonly employed traits like wood density or leaf mass per area, yield the power to predict growth. Critically, we observe a shift from growth being controlled by traits related to carbon cycling (assimilation and respiration) in well-watered trees, to traits relating to plant hydraulic stress in drought-stressed trees. We also demonstrate that even with a very comprehensive set of plant traits and growth data on large numbers of tropical trees, considerable uncertainty remains in directly interpreting the mechanisms through which traits influence performance in tropical forests.Conselho Nacional de Desenvolvimento Científico e TecnológicoNatural Environment Research Council (NERC)Australian Research Council (ARC)European Union FP7Fundação de Amparo à Pesquisa do Estado de São Paul

Características clínicas e epidemiológicas do câncer da boca em hospital-escola de 1994 a 2002: aumento da incidência em mulheres, predomínio de doença local avançada e baixa incidência de metástases regionais

PURPOSE: Description of clinical and epidemiological characteristics of patients who underwent surgery for oral cancer in a Medical School Teaching Hospital, and determination of differences with respect to other institutions and/or periods of time. METHOD: The charts of patients undergoing surgery for oral cancer from 1994 to 2002 were reviewed. Data were collected in a spreadsheet in order to analyze clinical and epidemiological features.. RESULTS: A total of 374 patients having undergone 406 operations was identified. Their ages varied from 14 to 94 years (mean = 57.4 years), with 255 men (68.2%), and 295 out 366 Caucasian (80.6%). A majority had tumors of the tongue and/or floor of mouth (55.6%), while 20.3% had lip cancer. Squamous cell carcinoma was found in 90.3%, and glandular carcinoma in 4%. T4 tumors in 39.6%, Tis or T1 lesions in 15.2% of all patients. Nearly 62% had no regional metastases, and the relative incidence in young patients (40 years or younger) reached 8.6%. CONCLUSION: In spite of the predominance of locally advanced tumors, a majority of patients had no neck metastases. The 31.8% incidence in females indicates an increasing incidence of oral cavity cancer among women when compared to previous periods at the same institution.OBJETIVO: Caracterizar epidemiológica e clinicamente a população atendida por câncer de boca em hospital-escola de atenção terciária e quaternária e verificar variações em relação a outras casuísticas e períodos. MÉTODO: Procedeu-se à revisão dos prontuários dos operados por câncer oral de 1994 a 2002. As características clínicas e epidemiológicas foram colocadas em planilhas e analisadas. RESULTADOS: Foram identificados 374 portadores de câncer da boca que foram submetidos a 406 operações. A idade dos doentes variou de 14 a 94 anos (média = 57,4 anos). Duzentos e cinqüenta e cinco eram do gênero masculino (68,2%). Duzentos e noventa e cinco entre 366 doentes eram caucasianos (80,6%). A maioria era portadora de tumores da língua e/ou do soalho da boca (194 entre 349 doentes; 55,6%), e 71 (20,3%) tinham tumores dos lábios. O carcinoma epidermóide foi encontrado em 90,3% e carcinomas glandulares em 4%. Os tumores T4 estavam presentes em 39,6% dos doentes; 15,2% tinham lesões Tis ou T1. Quase 62% dos pacientes não tinham metástases cervicais. A incidência relativa em jovens (com até 40 anos de idade) atingiu 8,6%. CONCLUSÃO: Apesar dos achados freqüentemente referidos na literatura terem se confirmado (como o predomínio de lesões avançadas localmente), a maioria dos doentes não apresentava metástases cervicais. Acima do observado em outras casuísticas, os 31,8% de mulheres na presente casuística indica a preocupante e crescente incidência no gênero feminino

Spinning Conformal Correlators

We develop the embedding formalism for conformal field theories, aimed at doing computations with symmetric traceless operators of arbitrary spin. We use an index-free notation where tensors are encoded by polynomials in auxiliary polarization vectors. The efficiency of the formalism is demonstrated by computing the tensor structures allowed in n-point conformal correlation functions of tensors operators. Constraints due to tensor conservation also take a simple form in this formalism. Finally, we obtain a perfect match between the number of independent tensor structures of conformal correlators in d dimensions and the number of independent structures in scattering amplitudes of spinning particles in (d+1)-dimensional Minkowski space.Comment: 46 pages, 3 figures; V2: references added; V3: tiny misprint corrected in (A.9

The response of carbon assimilation and storage to long‐term drought in tropical trees is dependent on light availability

Whether tropical trees acclimate to long‐term drought stress remains unclear. This uncertainty is amplified if drought stress is accompanied by changes in other drivers such as the increases in canopy light exposure that might be induced by tree mortality or other disturbances. Photosynthetic capacity, leaf respiration, non‐structural carbohydrate (NSC) storage and stomatal conductance were measured on 162 trees at the world's longest running (15 years) tropical forest drought experiment. We test whether surviving trees have altered strategies for carbon storage and carbon use in the drier and elevated light conditions present following drought‐related tree mortality. Relative to control trees, the surviving trees experiencing the drought treatment showed functional responses including: (a) moderately reduced photosynthetic capacity; (b) increased total leaf NSC; and (c) a switch from starch to soluble sugars as the main store of branch NSC. This contrasts with earlier findings at this experiment of no change in photosynthetic capacity or NSC storage. The changes detected here only occurred in the subset of drought‐stressed trees with canopies exposed to high radiation and were absent in trees with less‐exposed canopies and also in the community average. In contrast to previous results acquired through less intensive species sampling from this experiment, we also observe no species‐average drought‐induced change in leaf respiration. Our results suggest that long‐term responses to drought stress are strongly influenced by a tree's full‐canopy light environment and therefore that disturbance‐induced changes in stand density and dynamics are likely to substantially impact tropical forest responses to climate change. We also demonstrate that, while challenging, intensive sampling is essential in tropical forests to avoid sampling biases caused by limited taxonomic coverage.Publicado online em 29 set. 2020

Properties and characterization of biodegradable films obtained from different starch sources.

The increasing use of natural biodegradable polymers to preserve foods is a consequence of the concern of society with sustainability. Starch stands out amongst the natural polymers due to its great availability on a worldwide scale, high extraction yield and nutritional value, low cost, biodegradability and biocompatibility. Apart from the traditional sources, various others exist with extraction potential. The objective of this study was to identify films from different non-traditional starch sources with properties revealing their potential to be applied as coating for fruits and vegetables. The biodegradable films were prepared with three starch concentrations (2, 3 and 3.5%) for each of the following sources: cassava, yam, jackfruit seed and mango kernel. The starches from the sources studied are promising ingredients for the formulation of films, presenting good physical, optical (such as transparency) and mechanical characteristics, principally tensile strength whose maximum value was 36.63 MPa. Increases in starch concentration directly influenced the thickness, water vapor permeability, tensile strength and puncture force. The films with the greatest potentials for use according to their characteristics were 3% cassava, 3% yam, 3.5% jackfruit seed and 2% mango.Supplement 2

Analyticity and the Holographic S-Matrix

We derive a simple relation between the Mellin amplitude for AdS/CFT correlation functions and the bulk S-Matrix in the flat spacetime limit, proving a conjecture of Penedones. As a consequence of the Operator Product Expansion, the Mellin amplitude for any unitary CFT must be a meromorphic function with simple poles on the real axis. This provides a powerful and suggestive handle on the locality vis-a-vis analyticity properties of the S-Matrix. We begin to explore analyticity by showing how the familiar poles and branch cuts of scattering amplitudes arise from the holographic description. For this purpose we compute examples of Mellin amplitudes corresponding to 1-loop and 2-loop Witten diagrams in AdS. We also examine the flat spacetime limit of conformal blocks, implicitly relating the S-Matrix program to the Bootstrap program for CFTs. We use this connection to show how the existence of small black holes in AdS leads to a universal prediction for the conformal block decomposition of the dual CFT.Comment: 28+15 pages, 7 figures; v2: typos correcte

Spinning Conformal Blocks

For conformal field theories in arbitrary dimensions, we introduce a method to derive the conformal blocks corresponding to the exchange of a traceless symmetric tensor appearing in four point functions of operators with spin. Using the embedding space formalism, we show that one can express all such conformal blocks in terms of simple differential operators acting on the basic scalar conformal blocks. This method gives all conformal blocks for conformal field theories in three dimensions. We demonstrate how this formalism can be applied in a few simple examples.Comment: 29 page

Open Strings in Exactly Solvable Model of Curved Spacetime and PP-Wave Limit

In this paper we study the superstring version of the exactly solvable string model constructed by Russo and Tseytlin. This model represents superstring theory in a curved spacetime and can be seen as a generalization of the Melvin background. We investigate D-branes in this model as probes of the background geometry by constructing the boundary states. We find that spacetime singularities in the model become smooth at high energy from the viewpoint of open string. We show that there always exist bulk (movable) D-branes by the effect of electric flux. The model also includes Nappi-Witten model as the Penrose limit and supersymmetry is enhanced in the limit. We examine this phenomenon in the open string spectrum. We also find the similar enhancement of supersymmetry can be occurred in several coset models.Comment: Latex, 32 pages, typos corrected, references added, to appear in JHEP, eq.(2.22) correcte