Short proofs of the Quantum Substate Theorem

The Quantum Substate Theorem due to Jain, Radhakrishnan, and Sen (2002) gives us a powerful operational interpretation of relative entropy, in fact, of the observational divergence of two quantum states, a quantity that is related to their relative entropy. Informally, the theorem states that if the observational divergence between two quantum states rho, sigma is small, then there is a quantum state rho' close to rho in trace distance, such that rho' when scaled down by a small factor becomes a substate of sigma. We present new proofs of this theorem. The resulting statement is optimal up to a constant factor in its dependence on observational divergence. In addition, the proofs are both conceptually simpler and significantly shorter than the earlier proof.Comment: 11 pages. Rewritten; included new references; presented the results in terms of smooth relative min-entropy; stronger results; included converse and proof using SDP dualit

Influence of drainage status on soil and water chemistry, litter decomposition and soil respiration in central Amazonian forests on sandy soils

Central Amazonian rainforest landscape supports a mosaic of tall terra firme rainforest and ecotone campinarana, riparian and campina forests, reflecting topography-induced variations in soil, nutrient and drainage conditions. Spatial and temporal variations in litter decomposition, soil and groundwater chemistry and soil CO2 respiration were studied in forests on sandy soils, whereas drought sensitivity of poorly-drained valley soils was investigated in an artificial drainage experiment. Slightly changes in litter decomposition or water chemistry were observed as a consequence of artificial drainage. Riparian plots did experience higher litter decomposition rates than campina forest. In response to a permanent lowering of the groundwater level from 0.1 m to 0.3 m depth in the drainage plot, topsoil carbon and nitrogen contents decreased substantially. Soil CO2 respiration decreased from 3.7±0.6 µmol m-2 s-1 before drainage to 2.5±0.2 and 0.8±0.1 µmol m-2 s-1 eight and 11 months after drainage, respectively. Soil respiration in the control plot remained constant at 3.7±0.6 µmol m-2 s-1. The above suggests that more frequent droughts may affect topsoil carbon and nitrogen content and soil respiration rates in the riparian ecosystem, and may induce a transition to less diverse campinarana or short-statured campina forest that covers areas with strongly-leached sandy soil

Evaluating Sums over the Matsubara Frequencies

Perturbative calculations in field theory at finite temperature involve sums over the Matsubara frequencies. Besides the usual difficulties that appear in perturbative computations, these sums give rise to some new obstacles that are carefully analized here. I present a fast and realible recipe to work out sums over the Matsubara frequencies. As this algorithm leads to deal with very cumbersome algebraic expressions, it has been written for computers by using the symbolic manipulation program Mathematica. It is also shown this algorithm to be self-consistent when it is applied to more than one loop computations.Comment: 10 page

Measurements of soil respiration and simple models dependent on moisture and temperature for an Amazonian southwest tropical forest

Soil respiration plays a significant role in the carbon cycle of Amazonian tropical forests, although in situ measurements have only been poorly reported and the dependence of soil moisture and soil temperature also weakly understood. This work investigates the temporal variability of soil respiration using field measurements, which also included soil moisture, soil temperature and litterfall, from April 2003 to January 2004, in a southwest Brazilian tropical rainforest near Ji-Paraná, Rondônia. The experimental design deployed five automatic (static, semi-opened) soil chambers connected to an infra-red CO2 gas analyzer. The mean half-hourly soil respiration showed a large scattering from 0.6 to 18.9 µmol CO2 m-2 s-1 and the average was 8.0±3.4 µmol CO2 m-2 s-1. Soil respiration varied seasonally, being lower in the dry season and higher in the wet season, which generally responded positively to the variation of soil moisture and temperature year round. The peak was reached in the dry-to-wet season transition (September), this coincided with increasing sunlight, evapotranspiration and ecosystem productivity. Litterfall processes contributed to meet very favorable conditions for biomass decomposition in early wet season, especially the fresh litter on the forest floor accumulated during the dry season. We attempted to fit three models with the data: the exponential Q10 model, the Reichstein model, and the log-soil moisture model. The models do not contradict the scattering of observations, but poorly explain the variance of the half-hourly data, which is improved when the lag-time days averaging is longer. The observations suggested an optimum range of soil moisture, between 0.11

From the production of rules to seed production: global intellectual property and local knowledge.

This paper analyzes the links and overlappings between traditional knowledge and biodiversity in the context of ecological family farming in southern Brazil. The data presented are part of an ethnographic study carried out among a network of ecological farmers, Ecovida, in the west of Santa Catarina state. The current global patent regime, most prominently the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPs) of the World Trade Organization (WTO), has had direct effects on seed production and agricultural food crops. In a scenario of increasing creation of patents, patent regulations, provisions on cultivars (plant varieties and seed breeding) and a number of other global trade control mechanisms, family farmers and other related social actors have rejected the multilateral development agencies' notion of life as "resource". This study has a two-fold aim: first, it approaches the international context of the intellectual property regime on biodiversity and knowledge production; second, it examines the actions taken by farmers participating in the Ecovida network toward creating alternative ways of managing knowledge to produce "free" seeds. As an outcome, there is a parallel political action of criticism and resistance to the current narrowing of agriculture's genetic base, and organized efforts to multiply seeds, know-how and knowledge through networks, banks and centers of agro-biodiversity. Our central argument is that all these social actors - who make up the so-called ecological network and who seek, in their activities, to carry on the multiplication and variability of seeds and promote the diversity of knowledge to produce diverse seeds - are also creating collective strategies of social resistance vis-à-vis the prevailing global modes of controlling knowledge, seeds and food production