Assessing the Harvest Maturity of Brazilian Mangoes

No clear criterion exists to determine the optimum time to harvest mango. Some empirical relations are used to assess maturity, such as shoulder development. Moreover, as a result of the typical growing conditions in tropical climates, a huge variation in maturity and ripeness exists, seriously hampering the export of fruit in the global chain. The consequence for consumers in western countries is that sometimes mangoes are overripe at the retailer, or have to be kept for several days, even weeks, to reach the edible state, provided they do not rot in the meantime. To ensure an edible quality, the chlorophyll content in the fruit flesh, measured at harvest by Time-resolved Reflectance Spectroscopy (TRS), could be used as a maturity criterion for mango fruit. Commercially grown fruit were harvested in Brazil and transported to Italy by plane. Fruits were measured using TRS at 630 nm for absorption coefficient (µa) and skin colour. The development of µa was followed on 60 fruits during 15 days of storage at 20°C. The remainders of fruit were used to measure firmness destructively. Absorption coefficient decreased during shelf life according to a logistic pattern, as expected for colour development. Taking the variation between the individual fruit into account, 72% of the variation was accounted for. Nevertheless, µa assessed at harvest could be converted into a biological shift factor (BSF), as an expression of the maturity at harvest of each individual fruit. This biological shift factor explained about 70% of the variation in firmness development in individual fruit. These preliminary results indicate that TRS methodology coupled with BSF theory could be useful in assessing maturity at harvest and assuring acceptable eating quality of mango

On Aharonov-Casher bound states

In this work bound states for the Aharonov-Casher problem are considered. According to Hagen's work on the exact equivalence between spin-1/2 Aharonov-Bohm and Aharonov-Casher effects, is known that the $\boldsymbol{\nabla}\cdot\mathbf{E}$ term cannot be neglected in the Hamiltonian if the spin of particle is considered. This term leads to the existence of a singular potential at the origin. By modeling the problem by boundary conditions at the origin which arises by the self-adjoint extension of the Hamiltonian, we derive for the first time an expression for the bound state energy of the Aharonov-Casher problem. As an application, we consider the Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the expression for the harmonic oscillator energies and compare it with the expression obtained in the case without singularity. At the end, an approach for determination of the self-adjoint extension parameter is given. In our approach, the parameter is obtained essentially in terms of physics of the problem.Comment: 11 pages, matches published versio

meso-1-{[2-(Propyl-1-sulfin­yl)eth­yl]sulfin­yl}propane

The title mol­ecule, C8H18O2S2, is disposed about a centre of inversion implying an anti-disposition of the sulfinyl-O atoms; the terminal n-propyl group has an extended conformation. The crystal packing is dominated by C—H⋯O inter­actions, which lead to the formation of supra­molecular arrays in the bc plane

Aparência, compostos fenólicos e enzimas oxidativas em uva `Itália` sob influencia do cálcio e do armazenamento refrigerado.

O objetivo deste trabalho foi determinar o efeito da aplicacao pre-colheita de calcio na aparencia (secamento do engaco, danos mecanicos e podridoes), teor de fenolicos e enzimas oxidativas (polifenoloxidase e peroxidase) em uva. Os cachos de uca Italia de um cultivo comercial em Petrolina, Pernambuco, Brasil, foram marcados e imersos por 10 segundos, em solucoes de Ca a 0 e 1,5%, na forma de cloreto de calcio, aos 57 dias apos o inicio da formacao dos frutos (quando as bagas comecaram a mudar de cor e amolecer). Apos a colheita, os frutos foram armazenados a 3,5 mai ou menos 0,2oC e 93 mais ou menos 6% UR e avaliados aos 0; 14; 28; 42; 56 e 70 dias. Houve um incremento no secamento do engraco, no aparecimento de sintomas de danos mecanicos e de podridoes nas bags com o tempo de armazenamento. A aplicacao de calcio reduziu a atividade de polifenoloxidase e, consequentemente, os sintomas de danos mecanicos, resultando numa melhor aparencia. A vida util das uvas foi de aproximadamente 56 dias, quando sintomas de senescencia, podridoes e o nivel dos sintomas de danos mecanicos comecaram a aumentar de forma significativa

O centenário da molécula de Bohr

A hundred years ago, a twenty-eight year old Danish scientist published a series of three papers in which electron motion was quantized. The Bohr atomic model is surely known by every chemistry student. Nevertheless in this same 1913 trilogy, Bohr studied atoms with several electrons as well as molecules. Chemistry students, in general, are not aware of the Bohr molecule. The present paper aims at rescuing this important classical model. A review of the Bohr atomic model for both one and several electrons is discussed, together with a theoretical presentation of the Bohr molecule

Arranjos produtivos locais no Estado do Pará: localização espacial das atividades florestal e de madeira e mobiliário.

Dada a necessidade de conhecer melhor a viabilidade econômica e o nível tecnológico de produção da mamona no Estado do Ceará, considerado um dos maiores produtores de oleaginosas no Nordeste do Brasil, este trabalho objetivou determinar o nível tecnológico e elaborar um balanço econômico da produção da mamona para obtenção de biodiesel no Estado do Ceará. A pesquisa foi realizada nos munícípios de Boa Viagem, Tauá e Pedra Branca. A produção de mamona cearense, nos três municípios analisados, mostrou-se rentável, tendo sido a utilização de mão-de-obra familiar um fator primordial para se ter baixo custo de produção.Disponível também on-line

Experimental implementation of a NMR entanglement witness

Entanglement witnesses (EW) allow the detection of entanglement in a quantum system, from the measurement of some few observables. They do not require the complete determination of the quantum state, which is regarded as a main advantage. On this paper it is experimentally analyzed an entanglement witness recently proposed in the context of Nuclear Magnetic Resonance (NMR) experiments to test it in some Bell-diagonal states. We also propose some optimal entanglement witness for Bell-diagonal states. The efficiency of the two types of EW's are compared to a measure of entanglement with tomographic cost, the generalized robustness of entanglement. It is used a GRAPE algorithm to produce an entangled state which is out of the detection region of the EW for Bell-diagonal states. Upon relaxation, the results show that there is a region in which both EW fails, whereas the generalized robustness still shows entanglement, but with the entanglement witness proposed here with a better performance