Basal chromodorid sperm ultrastructure (Nudibranchia, Gastropoda, Mollusca)

The relationship between three genera considered basal in the Chromodorididae (Cadlina, Tyrinna, Cadlinella) has not yet been resolved by traditional morphological means. Here we examined the sperm ultrastructure of Tyrinna nobilis, Tyrinna evelinae, Cadlina flavomaculata and Cadlina cf. nigrobranchiata, with the expectation of finding phylogenetically informative characters. No Tyrinna or Cadlina species showed sperm similarities to Cadlinella. Both Cadlina species and Tyrinna nobilis (but not T. evelinae) exhibited coarse striations in the acrosomal pedestal. The putative fibers that occurred between the coarse striations of the pedestal are condensed into a layer in Cadlina and Tyrinna, but not in other species that also have coarse striations (Gymnodoris), and may constitute evidence for a close relationship. Tyrinna evelinae possessed fine acrosomal striations, which was shared with other Chromodorididae, Actinocyclidae and the cryptobranchs Rostanga and Aphelodoris. We also examined the sperm ultrastructure of 'Chromodoris' ambiguus, an animal which has shown molecular affinities to species of Cadlina, and not Chromodoris. The sperm of 'C'.' ambiguus did not exhibit the typical Cadlina characteristics, but also showed important differences to other investigated Chromodoris species.

Theoretical analysis of ocean color radiances anomalies and implications for phytoplankton groups detection in case 1 waters

Past years have seen the development of different approaches to detect phytoplankton groups from space. One of these methods, the PHYSAT one, is empirically based on reflectance anomalies. Despite observations in good agreement with in situ measurements, the underlying theoretical explanation of the method is still missing and needed by the ocean color community as it prevents improvements of the methods and characterization of uncertainties on the inversed products. In this study, radiative transfer simulations are used in addition to in situ measurements to understand the organization of the signals used in PHYSAT. Sensitivity analyses are performed to assess the impact of the variability of the following three parameters on the reflectance anomalies: specific phytoplankton absorption, colored dissolved organic matter absorption, and particles backscattering. While the later parameter explains the largest part of the anomalies variability, results show that each group is generally associated with a specific bio-optical environment which should be considered to improve methods of phytoplankton groups detection.

Sunglasses, traffic signals, and color vision deficiencies

Purpose: To determine (a) the effect of different sunglass tint colorations on traffic signal detection and recognition for color normal and color deficient observers, and (b) the adequacy of coloration requirements in current sunglass standards. Methods: Twenty color-normals and 49 color-deficient males performed a tracking task while wearing sunglasses of different colorations (clear, gray, green, yellow-green, yellow-brown, red-brown). At random intervals, simulated traffic light signals were presented against a white background at 5° to the right or left and observers were instructed to identify signal color (red/yellow/green) by pressing a response button as quickly as possible; response times and response errors were recorded. Results: Signal color and sunglass tint had significant effects on response times and error rates (p < 0.05), with significant between-color group differences and interaction effects. Response times for color deficient people were considerably slower than color normals for both red and yellow signals for all sunglass tints, but for green signals they were only noticeably slower with the green and yellow-green lenses. For most of the color deficient groups, there were recognition errors for yellow signals combined with the yellow-green and green tints. In addition, deuteranopes had problems for red signals combined with red-brown and yellow-brown tints, and protanopes had problems for green signals combined with the green tint and for red signals combined with the red-brown tint. Conclusions: Many sunglass tints currently permitted for drivers and riders cause a measurable decrement in the ability of color deficient observers to detect and recognize traffic signals. In general, combinations of signals and sunglasses of similar colors are of particular concern. This is prima facie evidence of a risk in the use of these tints for driving and cautions against the relaxation of coloration limits in sunglasses beyond those represented in the study.

Synthesis of novel poly[(2,5-dimethoxy-p-phenylene)vinylene] precursors having two eliminatable groups: An approach for the control of conjugation length

Poly[(2,5-dimethoxy-p-phenylene)vinylene] (DMPPV) of varying conjugation length was synthesized by selective elimination of organic soluble precursor polymers that contained two eliminatable groups, namely, methoxy and acetate groups. These precursor copolymers were in turn synthesized by competitive nucleophilic substitution of the sulfonium polyelectrolyte precursor (generated by the standard Wessling route) using methanol and sodium acetate in acetic acid. The composition of the precursor copolymer, in terms of the relative amounts of methoxy and acetate groups, was controlled by varying the composition of the reaction mixture during nucleophilic substitution. Thermal elimination of these precursor copolymers at 250 degrees C, yielded partially conjugated polymers, whose color varied from light yellow to deep red. FT-IR studies confirmed that, while essentially all the acetate groups were eliminated, the methoxy groups were intact and caused the interruption in conjugation. Preliminary photoluminescence studies of the partially eliminated DMPPV samples showed a gradual shift in the emission maximum from 498 to 598 nm with increasing conjugation lengths, suggesting that the color of LED devices fabricated from such polymers can, in principle, be fine-tuned.

Adolpf Molling, Janet Krakauer nee McColl, Hymie Joachim and Thomas Krakauer (l-r); Weggis, Switzerland Portraits Groups

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Adolpf Molling, Janet Krakauer nee McColl, Hymie Joachim and Thomas Krakauer (l-r); Weggis, Switzerland Portraits Groups

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Group portrait of the American Jewish Joint Distribution Committee; Shanghai Portraits; Groups

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Non-Abelian monopoles break color. II. Field theory and quantum mechanics

Many grand unified theories (GUT's) predict non-Abelian monopoles which are sources of non-Abelian (and Abelian) magnetic flux. In the preceding paper, we discussed in detail the topological obstructions to the global implementation of the action of the "unbroken symmetry group" H on a classical test particle in the field of such a monopole. In this paper, the existence of similar topological obstructions to the definition of H action on the fields in such a monopole sector, as well as on the states of a quantum-mechanical test particle in the presence of such fields, are shown in detail. Some subgroups of H which can be globally realized as groups of automorphisms are identified. We also discuss the application of our analysis to the SU(5) GUT and show in particular that the non-Abelian monopoles of that theory break color and electroweak symmetries.

Colorimetric determination of 2,4-dinitrophenylamino groups by sodium borohydride reduction

When sodium borohydride is added to aqueous solutions of 2,4-dinitrophenylamino acids and related derivatives, an intense red color is formed. Measurement of the red color, with a 420 filter, permits the determination of such compounds in concentrations of 0.01 to 0.06 μmole per ml. with a precision to 2%. The reaction is highly specific-while 2,4-dinitroaniline will react to the test, o-, m-, and p-nitroanilines, 2,4-dinitrophenyl aryl or alkyl ethers, and 2,4-dinitrophenyl-imidazole and pyrrolidine derivatives will not. Heretofore aromatic nitro groups have been considered resistant to attack by sodium borohydride. The method, as developed, is applicable to the evaluation of the degree of substitution of protein amino groups by fluorodinitrobenzene.

Manipulating charge-transfer character with electron-withdrawing main-group moieties for the color tuning of iridium electrophosphors

A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy=2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)(2)(acac)] (X=B(Mes)(2), SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations.

A versatile color tuning strategy for iridium(III) and platinum(II) electrophosphors by shifting the charge-transfer states with an electron-deficient core

By fusing an electron-deficient ring system with the phenyl ring of a 2-phenylpyridine (ppy)-type ligand, a new and synthetically versatile strategy for the phosphorescence color tuning of cyclometalated iridium(III) and platinum(II) metallophosphors has been established. Two robust red electrophosphors with enhanced electron-injection/electron-transporting features were prepared by using an electron-trapping fluoren-9-one chromophore in the ligand design. The thermal, photophysical, redox and electrophosphorescent properties of these complexes are reported. These exciting results can be attributed to a switch of the metal-to-ligand charge-transfer (MLCT) character of the transition from the pyridyl groups in the traditional Ir-III or Pt-II ppy-type complexes to the electron-deficient ring core, and the spectral assignments corroborate well with the electrochemical data as well as the timedependent density functional theory (TD-DFT) calculations. The electron-withdrawing character of the fused ring results in much more stable MLCT states, inducing a substantial red-shift of the triplet emission energy from yellow to red for the Ir-III complex and even green to red for the PtII counterpart.

Effects of different light sources and illumination methods on growth and body color of shrimp Litopenaeus vannamei

Shrimps Litopenaeus vannamei with initial body weight of 2.108 +/- 0.036 g were sampled for specific growth rates (SGR) and body color measurements for 50 days under different light sources (incandescent lamp, IL; cool-white fluorescent lamp, FL; metal halide lamp, MHL; and control without lamp) and different illumination methods (illumination only in day, IOD, and illumination day and night, IDN). Body color of L. vannamei was measured according to the free astaxanthin concentration (FAC) of shrimp. The SGR, food intake (FI), feed conversion efficiency (FCE) and FAC of shrimps showed significant differences among the experimental treatment groups (P < 0.05). Maximum and minimum SGR occurred under IOD by MHL and IDN by FL, respectively (difference 56.34%). The FI of shrimp for the control group did not rank lowest among treatments, confirming that shrimp primarily use scent, not vision, to search for food. FI and FCE of shrimps were both the lowest among treatment groups under IDN by FL and growth was slow, thus FL is not a preferred light source for shrimp culture. Under IOD by MHL, shrimps had the highest FCE and the third highest FI among treatment groups ensuring rapid growth. FAC of shrimp were about 3.31 +/- 0.20 mg/kg. When under IOD by MHL and IDN by FL, FAC was significantly higher than the other treatments (P < 0.05). To summarize, when illuminated by MHL, L. vannamei had not only vivid body color due to high astaxanthin concentration but also rapid growth. Therefore, MHL is an appropriate indoor light source for shrimp super-intensive culture. SGR of shrimp was in significantly negative correlation to FAC of shrimp (P < 0.05). Thus, when FAC increased, SGR did not always follow, suggesting that the purpose of astaxanthin accumulation was not for growth promotion but for protection against intense light. (c) 2005 Elsevier B.V. All rights reserved.

Generalized ocean color inversion model for retrieving marine inherent optical properties

Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the color of the water observed by the satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few are appropriately parameterized for all water masses for all seasons. To initiate community-wide discussion of these limitations, NASA organized two workshops that deconstructed SAAs to identify similarities and uniqueness and to progress toward consensus on a unified SAA. This effort resulted in the development of the generalized IOP (GIOP) model software that allows for the construction of different SAAs at runtime by selection from an assortment of model parameterizations. As such, GIOP permits isolation and evaluation of specific modeling assumptions, construction of SAAs, development of regionally tuned SAAs, and execution of ensemble inversion modeling. Working groups associated with the workshops proposed a preliminary default configuration for GIOP (GIOP-DC), with alternative model parameterizations and features defined for subsequent evaluation. In this paper, we: (1) describe the theoretical basis of GIOP; (2) present GIOP-DC and verify its comparable performance to other popular SAAs using both in situ and synthetic data sets; and, (3) quantify the sensitivities of their output to their parameterization. We use the latter to develop a hierarchical sensitivity of SAAs to various model parameterizations, to identify components of SAAs that merit focus in future research, and to provide material for discussion on algorithm uncertainties and future emsemble applications.

Color preferences in gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes)

Color plays an important biological role in the lives of many animals, with some species exhibiting preferences for certain colors over others. This study explored the color preferences of two species of ape, which, like humans, possess trichromatic color vision. Six western lowland gorillas, and six chimpanzees, housed in Belfast Zoological Gardens, were exposed to three stimuli (cloths, boxes, sheets of acetate) in red, blue, and green. Six stimuli of the same nature, in each of the three colors, were provided to both species for 5 days per stimulus. The amount of interest that the animals showed toward each stimulus of each color was recorded for 1 hr. Results showed that the apes, both when analyzed as two separate groups, and when assessed collectively, showed significant color preferences, paying significantly less attention to the red-, than to the blue- or green-colored stimuli. The animals' interest in the blue- and green-colored stimuli did not differ significantly. Overall, the findings suggest that gorillas and chimpanzees, our closest living relatives, may harbor color preferences comparable to those of humans and other species. © 2008 American Psychological Association.


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Sensibilidad al contraste y percepción de color en pacientes con lentes intraoculares amarillos : estudio de corte transversal

El presente estudio descriptivo de corte transversal, comparó la percepción de color (Test de Farnsworth-100 y de Ishihara) y la sensibilidad al contraste en un grupo de 35 ojos con implantes de lentes intraoculares claros esféricos y otro grupo de 35 ojos con LIOs amarillos esféricos, para evaluar las diferencias entre tener o no el filtro de luz azul. Adicionalmente, después de un examen oftalmológico completo en el ojo a estudiar, se realizaron preguntas de satisfacción POP para evaluar el resultado subjetivo del procedimiento. Todos los pacientes tenían más de 3 meses POP. No se encontraron diferencias estadísticamente significativas en las pruebas de percepción de color que sugirieran que las alteraciones correspondían al filtro de luz azul, y aunque los pacientes con los LIOs amarillos lograron un mejor desempeño en la prueba de sensibilidad al contraste al analizarlos estadísticamente, clínicamente esto no parece tener importancia. La satisfacción general en ambos grupos tuvo una gran puntuación, y dentro de las molestias referidas más frecuentemente y que estaban presentes desde el procedimiento, se encontraban ardor ocular, lagrimeo y dificultad para ver de cerca sin corrección. Según estudios en modelos animales, hay evidencia que sugiere que los LIOs amarillos, al compararlos con LIOs claros, protegen de mejor manera la retina una vez el cristalino se ha retirado. Según este y otros estudios publicados a la fecha, la agudeza visual, sensibilidad al contraste y percepción de color no varían de manera importante entre ambos tipos de lentes en la población general.