Influence of the Abaeté River on the reproductive success of the neotropical migratory teleost Prochilodus argenteus in the São Francisco River,downstream from the Três Marias Dam,southeastern Brazil

The curimatã‐pacu Prochilodus argenteus is an important characiform from the São Francisco River basin that performs long‐distance migrations for spawning upstream during the rainy season, when the temperature and photoperiod are elevated. Despite the interruption of the migratory routes by the Três Marias Dam and accentuated decline in fishing, the curimatã‐pacu still sustains the fisheries at the Três Marias region in recent decades. The objective of this study was to evaluate the reproductive activity of P. argenteus in two sections of the São Francisco River, downstream from the Três Marias Dam, during the rainy season. In the first 34 km of the river, immediately below the dam, most of the females were in gonadal resting. At 34–54 km downstream from the dam, following the confluence with a medium‐sized tributary, the Abaeté River, there was a high frequency of males and females in reproductive activity. Follicular atresia was more frequent in the upper section of the river while postovulatory follicles occurred predominantly in the lower section. Fulton's condition factor and gonadosomatic index indicated that the females were in a better physiological and reproductive condition below the confluence with the Abaeté River. In contrast to the females, the males were less affected by damming, and testicular maturation was largely achieved in two river sections. Thus, although the section of the São Francisco River immediately below the Três Marias Dam was found to be unfavourable for the reproduction of the migratory fishes due principally to the hypolimnetic water from the reservoir, reproductive success of P. argenteus was achieved below the Abaeté River. In this section, the species encountered appropriate conditions for maturation and spawning, i.e. warm temperatures above 24°C, high water flow and dissolved oxygen, and low water transparency. These results indicate the importance of a non‐regulated tributary to minimize the ecological impact of a dam on the downstream native fish communities. Copyright © 2005 John Wiley & Sons, Ltd.     

Maturation of cleistothecia of Uncinula necator (powdery mildew) and release of ascospores in southern Australia

We paired genetically characterised isolates of U. necator under controlled conditions and raised the resultant cleistothecia to maturity. Progeny were recovered from cleistothecia formed in the glasshouse and growth room 97–110 days after cleistothecial initials were observed.
Cleistothecia collected from naturally infected leaves from vineyards in the Adelaide Plains and Langhorne Creek, South Australia, in March and April (autumn) 1998 and stored in the same vineyards, were induced to release ascospores in the laboratory between March 1998 and February 1999. This paper is the first report of cleistothecia of U. necator releasing ascospores during summer, autumn and winter in southern Australia. Cleistothecia did not require a period of over-wintering in order to release ascospores that infected detached grapevine leaves in vitro . Furthermore, cleistothecia that over-wintered in the field were triggered to release ascospores in the laboratory in spring. Release of ascospores in spring was coincident with observations of ascospore-derived infections in the Waite Campus vineyard, confirming that cleistothecia provide an additional source of primary inoculum for powdery mildew in South Australia. Autumn release of ascospores suggests the possibility that U. necator may complete two sexual generations per year in Mediterranean climates, with consequent increased risks of development of fungicide resistance and changes in pathogenicity.     

Preprocessing to CIECAM02 input color with chromatic background

A preprocessing to CIECAM02 input color for color appearance prediction was proposed. In this study, 8640 color appearance matching pairs (NCS color charts with red, green, yellow, and blue backgrounds in a light booth and their reproductions with gray background on a CRT screen) were obtained by psychophysical experiment using the simultaneous‐binocular technique. Because only the lightness of background is included in CIECAM02, a color inducing vector based on opponent‐colors theory was introduced to preprocess CIECAM02 inputs, so that CIECAM02 may predict the corresponding color of an input color with chromatic background as well. By data fitting, a color preprocessing formula describing a relationship between the color inducing vector and the NCS chromaticness was conducted. Furthermore, the formula's performance was tested and the results showed that it was good for implementing the color appearance prediction of input colors with different chromatic backgrounds.© 2006 Wiley Periodicals, Inc. Col Res Appl, 32, 40–46, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20287     

Accurate display gamma functions based on human observation

This article describes an accurate method to obtain the tone reproduction curve of display devices without using a measurement device. It is an improvement of an existing technique based on human observation, solving its problem of numerical instability and resulting in functions in log—log scale which correspond better to the nature of display devices. We demonstrate the efficiency of our technique on different monitor technologies, comparing it with direct measurements using a spectrophotometer. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 310–319, 2007     

SEIS流行病模型中各类人群的指数变化率

针对类似丙肝这种具有较长慢性阶段的流行病问题,依据仓室建模思想,建立并研究了一类具有变化的总人口数的含有易感者类、潜伏期类、染急性病者类和染慢性病者类的SEIS流行病模型.借助基本再生数R0和基本取代率R1,讨论了上述4类人群的指数变化率.     

己内酰胺在感光材料上的应用

介绍了己内酰胺衍生物在照相乳剂中的应用，对改善彩色影像的清晰度作了验证。     

Specifications of nanosecond laser ablation with solid targets,aluminum, silicon rubber,and polymethylmethacrylate (PMMA)

The ablation parameters such as threshold fluence, etch depth, ablation rate and the effect of material targets were investigated under the interaction of laser pulse with low intensity. The parameters of the laser system are: laser pulse energy in the range of 110–140 m J, wavelength1064 nm and pulse duration 20 ns. By macroscopic estimation of the outward images of the ablation and data obtained, we can conclude that the photothermal and photoionization processes have more influence for aluminum ablation. In contrast, for polymer samples, from the macroscopic observation of the border pattern at the irradiated spot, and also the data obtained from the experiment results, we deduce that both chemical change due to heating and photochemical dissociation were effective mechanisms of ablation. However, concerning the two polymer samples, apart from considering the same theoretical ablation model, it is conceived that the photomehanical specifications of PMMA are involved in the ablation parameters. The threshold fluence for an ablation rate of 30 laser shots were obtained as 12.4, 24.64, and 11.71 J cm~(-2), for aluminum, silicon rubber and polymethylmethacrylate(PMMA) respectively.The ablation rate is exponentially decreased by the laser-shot number, especially for aluminum.Furthermore, the etch depth after 30 laser shots was measured as 180, 630 and 870 μm, for aluminum, silicon rubber and PMMA, respectively.     

Seasonal testicular changes in <i>Dendropsophus minutus</i> Peters, 1872 (Anura,Hylidae)

The reproductive cycle in anurans may be either continuous or discontinuous. These differences may be connected to seasonal climate changes and/or to anthropic activity. Forty adult male individuals of the Dendropsophus minutus species were collected during one year, in the municipality of Chapada dos Guimarães (Mato Grosso, Brazil). The testicles were studied under light and transmission electron microscopy. No variations were observed when the diameter of the seminiferous tubules and the thickness of the interstitial tissue were studied. However, changes in spermatogenesis were conspicuous and indicated that the reproductive cycle of D. minutus in Chapada dos Guimarães is discontinuous and seems related to variations in air temperature and rainfall.     

Using Two‐Photon Excitation to Control Bending Motions in Molecular‐Crystal Nanorods

Molecular‐crystal nanorods composed of 9‐anthracenecarboxylic acid can undergo reversible bending due to molecular‐level geometry changes associated with the photodimerization of the molecules in the crystal lattice. The use of highly focused near‐IR femtosecond laser pulses results in two‐photon excitation of micrometer‐scale regions and is used to induce transient bends at various locations along the length of a single 200‐nm‐diameter nanorod. Bending can be observed in nanorods with diameters as small as 35 nm, and translational motion of a single nanorod could be induced by sequential bending of longer segments. A kinetic model is presented that quantitatively describes the bending and relaxation dynamics of individual rods. The results of this work show that it is possible to use laser excitation conditions to control the location, rate, and magnitude of photodeformations in these nanorods. The ability to control the motion of these ultrasmall photomechanical structures may be useful for manipulating objects on the nanoscale.     

跨媒体颜色再现方法的研究

总结了跨媒体复杂图像颜色再现方法的研究现状及发展方向,介绍了基于空间视觉的颜色再现、基于CIECAM02的颜色再现和基于图像色貌模型3种方法的研究内容及发展趋势;着重分析了跨媒体颜色再现的难点和突破点,应用前景方面的优势和显著的实际应用价值.