Photosynthetic light response curves in relation to illumination of adaxial and abaxial surfaces of sun and shade leaves of Vitis vinifera L.

The photosynthetic light response of adaxial (upper) and abaxial (lower) surfaces of sun- and shade-adapted leaves of cv. Grechetto/SO 4 was investigated. Vines were exposed to long-term shade by mounting a black polypropylene cover (40 % light transmittance) over the vines for 6 consecutive years. The mean leaf blade inclination varied from 81.4degrees(sun-exposed) to 15.4degrees (shaded) enabling a high light reception. At light saturation, the maximum rate of photosynthesis of sun and shade leaves were similar if the adaxial or the abaxial leaf surface or both sides were irradiated simultaneously. At lower photon flux density (PFD), the adaxial surface consistently fixed more CO2 than the abaxial surface in both leaf types. At PFD below saturation, simultaneous illumination of both leaf surfaces led to an increase of the rate of net photosynthesis (Pn) as compared to illumination of only one surface with the same PFD. Bilateral illumination increased the apparent quantum yield and the convexity coefficient (bending rate of the photosynthetic light response curve) as compared to irradiation of only one side of the blade, whereas the light compensation and saturation points were significantly lower. The possible significance of simultaneous irradiation of both leaf surfaces at low PFD on Pn is discussed

Manejo do dossel vegetativo e seu efeito nos componentes de produção da videira Merlot.

A poda verde é uma prática cultural utilizada para melhorar as condições do dossel vegetativo dos vinhedos, visando a favorecer a qualidade da uva e do vinho. Nesse sentido, realizou-se este experimento entre as safras de 1993/1994 e 1996/1997, com diferentes modalidades de poda verde, num vinhedo do cv. Merlot conduzido em latada. Houve 12 tratamentos e três repetições, sendo o delineamento experimental em blocos casualizados. Os tratamentos constituíram-se da testemunha e de 11 diferentes modalidades de poda verde, ou seja, desbrota, desponta e desfolha, algumas delas em diferentes épocas do ciclo vegetativo da videira. O componente principal 1, da análise de componentes principais (ACP) feita em cada ano, separadamente, mostra que o tratamento 10 (desbrota + desponta + desfolha realizada no início da floração, eliminando-se as folhas abaixo dos cachos) discriminou-se nos quatro anos, e os tratamentos 7 (desfolha realizada 21 dias antes da colheita, eliminando-se metade das folhas abaixo dos cachos) e 6 (desfolha realizada 21 dias antes da colheita, eliminando-se as folhas abaixo dos cachos), em três deles; a ACP da média dos quatro anos também evidencia essa discriminação entre eles. Constata-se que o tratamento 10 foi um dos que tiveram intensidade de poda verde mais intensa, caracterizando-se por variáveis indicativas de plantas com vigor e produtividade mais baixos que os demais

Neutron diffraction study of Bronze Age tools from second millennium BC dwellings in Italy

Neutron diffraction was utilized to characterise XX to XIII century BC bronze axes (Ancient to Late Bronze Age from “Terramare” and other Bronze Age settlements near Modena, Italy. Archaeometric metallurgy issues have been addressed by means of phase and texture analysis from measurements carried out at the ROTAX and GEM beam lines of the neutron spallation source ISIS of the Rutherford Appleton Laboratory (UK). Neutron data provide accurate composition and structural information from the bulk of the alloy, with good grain statistics, without limitations due to surface alterations and with few limitations as to sample size. Bronze composition results are in good agreement with data obtained by micro-sampling and traditional analytical techniques thus confirming the validity of the method used for a totally non-destructive determination of the alloy composition from precise lattice parameter measurements. Phase analysis from diffraction profiles provides identification and quantification of surface alteration and corrosion products, free of interference with the analysis of the bulk alloy. Furthermore, texture analysis techniques may yield information on the ancient production methods of the artefacts

Neutron diffraction study of Bronze Age tools from second millennium BC dwellings in Italy

Neutron diffraction was utilized to characterise XX to XIII century BC bronze axes (Ancient to Late Bronze Age) from "Terramare" and other Bronze Age settlements near Modena, Italy. Archaeometric metallurgy issues have been addressed by means of phase and texture analysis from measurements carried out at the ROTAX and GEM beam lines of the neutron spallation source ISIS of the Rutherford Appleton Laboratory (UK), Neutron data provide accurate composition and structural information from the bulk of the alloy, with good grain statistics, without limitations due to surface alterations and with few limitations as to sample size. Bronze composition results are in good agreement with data obtained by micro-sampling and traditional analytical techniques thus confirming the validity of the method used for a totally non-destructive determination of the alloy composition from precise lattice parameter measurements. Phase analysis from diffraction profiles provides identification and quantification of surface alteration and corrosion products, free of interference with the analysis of the bulk alloy. Furthermore, texture analysis techniques may yield information on the ancient production methods of the artefacts. © Società Italians di Fisica

Neutron diffraction study of Bronze Age tools from second millennium BC dwellings in Italy

Neutron diffraction was utilized to characterise XX to XIII century BC bronze axes (Ancient to Late Bronze Age from “Terramare” and other Bronze Age settlements near Modena, Italy. Archaeometric metallurgy issues have been addressed by means of phase and texture analysis from measurements carried out at the ROTAX and GEM beam lines of the neutron spallation source ISIS of the Rutherford Appleton Laboratory (UK). Neutron data provide accurate composition and structural information from the bulk of the alloy, with good grain statistics, without limitations due to surface alterations and with few limitations as to sample size. Bronze composition results are in good agreement with data obtained by micro-sampling and traditional analytical techniques thus confirming the validity of the method used for a totally non-destructive determination of the alloy composition from precise lattice parameter measurements. Phase analysis from diffraction profiles provides identification and quantification of surface alteration and corrosion products, free of interference with the analysis of the bulk alloy. Furthermore, texture analysis techniques may yield information on the ancient production methods of the artefacts

Archaeometric studies at the GILDA beamline at the European Synchrotron Radiation Facility

In the latest years archaeometry scientists have directed a growing interest to synchrotron radiation techniques. The Italian CRG beamline GILDA at the European Synchrotron Radiation Facility provides to the users the access to experimental techniques like X-ray absorption spectroscopy and diffraction that are of great potential usefulness in this field. Here we give a technical overview of the instrumentation available as well as some examples among the archaeometry studies presently in progress on the beamline

Colour assessment outcomes – a new approach to grading the severity of color vision loss

INTRODUCTION: Recent studies have shown that a significant percentage of subjects with anomalous, congenital trichromacy can perform the suprathreshold, colour-related tasks encountered in many occupations with the same accuracy as normal trichromats. In the absence of detailed, occupation-specific studies, an alternative approach is to make use of new findings and the statistical outcomes of past practices that have been considered safe to produce graded, justifiable categories of colour vision that can be enforced. METHODS: We analyzed traditional color assessment outcomes and measured severity of colour vision loss using the CAD test in 1363 subjects (336 normals, 705 deutan, 319 protan and 3 tritan). The severity of colour vision loss was measured in each subject and statistical, pass / fail outcomes established for each of the most commonly used, conventional colour assessment tests and protocols. RESULTS: The correlation between the number of Ishihara (IH) test plates subjects fail and the severity of RG colour vision loss was very poor. The 38 plates IH test has high sensitivity when no errors are allowed (i.e., only 0.71% deutans and 0.63% protans pass). Protocols based on zero errors are uncommon since 18.15% of normal trichromats fail. The most common protocols employ either the 24 or the 14 plates editions with two or less errors. These protocols pass almost all normal trichromats, but the deutans and some protans that also pass (when two or less errors are allowed) can be severely deficient. This is simply because the most challenging plates have not been included in the 24 and 14 plates editions. As a result, normals no longer fail, but the deutans and protans that pass have more severe loss of colour vision since they fail less challenging plates. The severity of colour vision loss was measured in each subject and statistical, pass / fail outcomes established for each of the most commonly used, conventional colour assessment tests and protocols. DISCUSSION: Historical evidence and new findings that relate severity of loss to the effective use of colour signals in a number of tasks provide the basis for a new colour grading system based on six categories. A single colour assessment test is needed to establish the applicant’s Colour Vision category which can range from ‘supernormal’ (CV0), for the most stringent, colour-demanding tasks, to ‘severe colour deficiency’, when red / green colour vision is either absent or extremely weak (CV5)

Ancient encaustic: An experimental exploration of technology, ageing behaviour and approaches to analytical investigation

The composition of the ancient wax-based painting technique known as encaustic has long been the subject of debate. Ancient sources provide few details of the technology, and modern understanding of the medium is restricted to theoretical interpretation and experimental observation. In this multi-analytical collaborative study, a number of analytical approaches were used to investigate the physical and molecular properties of a range of experimentally prepared encaustic paints before and after ageing. Analysis using gas chromatography mass spectrometry, Fourier transform infrared spectroscopy (invasive and non-invasive), X-ray diffraction and thermogravimetric analysis demonstrated how differences in the technology of production alter the properties and composition of the medium and showed how these are modified by the addition of pigment and the effects of ageing. Comparison of results from the different analytical techniques highlights the benefit of an integrated analytical approach to the analysis of ancient encaustic paints and the fundamental importance of insights from invasive study to evaluating the results of non-invasive analysis