Statistical characterization of residual noise in the low-rank approximation filter framework, general theory and application to hyperpolarized tracer spectroscopy

The use of low-rank approximation filters in the field of NMR is increasing due to their flexibility and effectiveness. Despite their ability to reduce the Mean Square Error between the processed signal and the true signal is well known, the statistical distribution of the residual noise is still undescribed. In this article, we show that low-rank approximation filters are equivalent to linear filters, and we calculate the mean and the covariance matrix of the processed data. We also show how to use this knowledge to build a maximum likelihood estimator, and we test the estimator's performance with a Montecarlo simulation of a 13C pyruvate metabolic tracer. While the article focuses on NMR spectroscopy experiment with hyperpolarized tracer, we also show that the results can be applied to tensorial data (e.g. using HOSVD) or 1D data (e.g. Cadzow filter).Comment: 26 pages, 7 figure

A Path-integral for the Master Constraint of Loop Quantum Gravity

In the present paper, we start from the canonical theory of loop quantum gravity and the master constraint programme. The physical inner product is expressed by using the group averaging technique for a single self-adjoint master constraint operator. By the standard technique of skeletonization and the coherent state path-integral, we derive a path-integral formula from the group averaging for the master constraint operator. Our derivation in the present paper suggests there exists a direct link connecting the canonical Loop quantum gravity with a path-integral quantization or a spin-foam model of General Relativity.Comment: 19 page

Contribution of irisin pathway in protective effects of mandarin juice (Citrus reticulata Blanco) on metabolic syndrome in rats fed with high fat diet

The beneficial effects of Citrus fruits and their secondary metabolites on the cardio- vascular system are well established. Moreover, growing evidence suggests beneficial role for prevention of obesity and related dysfunctions. Citrus reticulata Blanco (Rutaceae) is one of the most consumed Citrus fruits, but it is poorly investigated. Mandarin juice obtained from C. reticulata fruits, collected in the Horti Simplicium of Pisa Charterhouse, presents a high amount of flavanone glycosides, including hesper- idin and a number of polymethoxyflavonoids, in particular nobiletin and tangeretin. On Wistar rats fed with a high fat diet for 21 days, mandarin juice significantly con- tained the percentage weight gain, reduced visceral adipose tissue and the inflamma- tory markers TNF and IL-6. Furthermore, mandarin juice influenced irisin pathway, increasing its plasma levels. Finally, supplementation with mandarin juice contributed to improve mitochondrial membrane potential, partially compromised with high fat diet, making mitochondria less susceptible to harmful events, such as ischemia. Taken together, these results suggest that C. reticulata, through its main metabolites, is able to produce beneficial effects in metabolic syndrome and to promote browning pro- cess, through involvement of the novel interesting irisin pathway

Parâmetros para o manejo de irrigação da pupunheira no Vale do São Francisco.

O consumo de água e o coeficiente de cultura da pupuneira foram estimados do plantio até a quinta colheita de palmito, durante dois anos e três meses, em Juazeiro-BA. Os valores desses parâmetros aumentaram consideravelmente até o décimo terceiro mês após o plantio (primeira colheita), devido ao crescimento contínuo das plantas. Com os cortes realizados aproximadamente a cada três ou quatro meses, os valores apresentaram variações devido à redução do número de plantas por área

Yield and distribution of biomass and nutrients in peach palm cropped under irrigation in the semi-arid area of brazilian Northeast.

The objective of this paper was to quantify the biomass and the nutrient concentration in the components of the peach palm (Bactris gasipaes H.B.K.)

The volume operator in covariant quantum gravity

A covariant spin-foam formulation of quantum gravity has been recently developed, characterized by a kinematics which appears to match well the one of canonical loop quantum gravity. In particular, the geometrical observable giving the area of a surface has been shown to be the same as the one in loop quantum gravity. Here we discuss the volume observable. We derive the volume operator in the covariant theory, and show that it matches the one of loop quantum gravity, as does the area. We also reconsider the implementation of the constraints that defines the model: we derive in a simple way the boundary Hilbert space of the theory from a suitable form of the classical constraints, and show directly that all constraints vanish weakly on this space.Comment: 10 pages. Version 2: proof extended to gamma > 1

Produção de bananeira 'Grande Naine' superadensada e irrigada no Vale do São Francisco.

Objetivou-se com este trabalho verificar, nas condições do Submédio São Francisco, a resposta do adensamento de plantio na produtividade da cultura de bananeira Grande Nain

Distribuicao de raizes de pupunha (Bactris gasipae Kunth.) irrigada em Latossolo Vermelho Amarelo.

A distribuicao da massa seca radicular da pupunha irrigada por sulcos em um latossolo vermelho amarelo de Petrolina-PE, foi analisada para se determinar a profundidade efetiva das raizes