990 resultados para Color vision. Reproduction. Socio-sexual communication. Callithrix jacchus


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Birds have four spectrally distinct types of single cones that they use for colour vision. It is often desirable to be able to model the spectral sensitivities of the different cone types, which vary considerably between species. However, although there are several mathematical models available for describing the spectral absorption of visual pigments, there is no model describing the spectral absorption of the coloured oil droplets found in three of the four single cone types. In this paper, we describe such a model and illustrate its use in estimating the spectral sensitivities of single cones. Furthermore, we show that the spectral locations of the wavelengths of maximum absorbance (lambda(max)) of the short- (SWS), medium- (MWS) and long- (LWS) wavelength-sensitive visual pigments and the cut-off wavelengths (lambda(cut)) of their respective C-, Y- and R-type oil droplets can be predicted from the lambda(max) of the ultraviolet- (UVS)/violet- ( VS) sensitive visual pigment.

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Male Satin Bowerbirds (Ptilonorhynchus violaceus) build stick structures known as bowers that serve as the focus for courtships and matings. Males decorate their bowers with numerous coloured decorations and are known to steal these decorations from one another. We investigated the stealing of bower decorations among males at the Bunya Mountains in Queensland, Australia. We aimed to (1) determine which classes of decorations were targets for theft in the studied population, and (2) examine whether the frequency at which individual decorations were stolen related to their intrinsic properties. To address our first aim, all decorations on the bowers of 21 adult males were labelled and their movements tracked throughout one mating season. To address our second aim, decorations stolen at least three times during the season were collected and their morphological and reflectance properties compared to those of decorations that were not stolen. In terms of the classes of decorations, tail feathers of Crimson Rosella (Platycercus elegans) were stolen more than any other class of decoration, but blue plastic bottletops were the most popular decorations relative to their availability on bowers. Frequently stolen individual decorations were similar to non-stolen items in their weights and surface areas, but were darker blue in colour than the decorations never stolen. Both bottletops and feathers reflected higher levels of ultraviolet (UV) light than did all other classes of bower decorations tested, thus suggesting that males may be using UV reflectance in sexual signalling. The darker blue, stolen decorations may increase contrast between the decoration collection and the platform, while the UV-reflecting subset of most frequently stolen decorations (bottletops and feathers) may increase contrast within the decoration collection. This in turn may increase the attractiveness of the display to females.

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Gonodactyloid stomatopod crustaceans possess polarization vision, which enables them to discriminate light of different e-vector angle. Their unusual apposition compound eyes are divided by an equatorial band of six rows of enlarged, structurally modified ommatidia, the mid-band (MB). The rhabdoms of the two most ventral MB rows 5 and 6 are structurally designed for polarization vision. Here we show, with electrophysiological recordings, that the photoreceptors R1-R7 within these two MB rows in Gonodactylus chiragra are highly sensitive to linear polarized light of two orthogonal directions (PS=6.1). They possess a narrow spectral sensitivity peaking at 565 nm. Unexpectedly, photoreceptors within the distal rhabdomal tier of MB row 2 also possess highly sensitive linear polarization receptors, which are in their spectral and polarization characteristics similar to the receptors of MB rows 5 and 6. Photoreceptors R1-R7 within the remainder of the MB exhibit low polarization sensitivity (PS=2.3). Outside the MB, in the two hemispheres, R1-R7 possess medium linear polarization sensitivity (PS=3.8) and a broad spectral sensitivity peaking at around 500 nm, typical for most crustaceans. Throughout the retina the most distally situated UV-sensitive R8 cells are not sensitive to linear polarized light.

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Background: Although many studies have investigated sexual communication between parents and children in Kenya, none have focused singularly on grandparent and grandchild communication when grandparents are primary caregivers. Further, few studies have asked about specific topics related to sex, instead asking generally about “sex related topics” or focusing on HIV/AIDS. This research aims to investigate communication on ten specific sex- related topics between grandparents who are primary caregivers and their grandchildren. The primary research aim was to identify facilitators and barriers to grandparent-grandchild communication associated with frequency of communication. A secondary exploratory question was whether frequency of communication and youth satisfaction with communication were associated with youth’s desire for more communication in the future. Methods: The study was conducted in urban and peri-urban central Kenya. A convenience sample of 193 grandparents and 166 twelve to fifteen year old grandchildren were identified by community health workers. A cross sectional survey assessed nine potential barriers or facilitators to communication (e.g., frequency of communication, perceived grandparent knowledge, grandparent sense of responsibility to communication on a given topic) on ten specified sex- related topics (e.g., peer pressure on sex topics, romantic relationships, condoms). Bivariate and multivariable analyses identified significant associations between communication variables and the outcomes of interest. Results: Bivariate regression showed that higher grandchild age, grandchild gender, higher perceived grandparent knowledge, higher perceived grandparent comfort, higher grandparent-reported sense of responsibility, higher grandparent-reported belief that child should be aware of a given topic before initiating in sex, and higher youth’s own comfort during communication, were significantly associated with higher levels of communication frequency. In the multivariable model, higher grandchild age, gender, higher comfort during communication, and higher perceived grandparent knowledge remained significantly associated with higher levels communication frequency. For the secondary research question, higher communication frequency and higher levels of youth satisfaction were both significantly associated with higher levels of youth desire for more communication in bivariate regression, and higher levels of youth’s satisfaction with communication remained significantly associated with higher levels of youth’s desire for more in the adjusted analysis. Conclusions: This study found that several potential barriers and facilitators of communication are associated with both frequency of and youth’s desire for more communication. The association between grandchild age, gender and perceived grandparent knowledge and frequency of communication is similar to findings from other studies that have examined sex-related communication between parent primary caregivers and children. This finding has important implications for understanding grandparent and grandchild communication, and communication on specific topics in a population from Kenya. The positive association between youth satisfaction of and desire for more communication has important education policy and intervention implications, suggesting that if youth are satisfied with the communication with their caregivers, they may want to learn more.

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Sexual scripts—the definitions and expectations that individuals hold for sexual interactions—are thought to play an important role in the maintenance of sexual well-being. Sexual scripts can be rigid or flexible, and they can be concordant or discordant between members of a couple. Sex therapists support sexual script flexibility for maintaining sexual and relationship satisfaction when couples are navigating sexual issues. However, empirical research examining the role of sexual script flexibility and the degree of script concordance/discordance in couples’ sexual well-being has been limited, due in part to the limited measures available. Furthermore, within the existing research, there has been an unfortunate tendency to exclude individuals in same-gender relationships – perpetuating the long-standing knowledge gap in the literature on positive sexuality in diverse relationships. To address these gaps in the literature, we conducted a series of online studies that recruited individuals in diverse relationships. A measure of individual sexual script flexibility in response to sexual issues was developed (Chapter 2); in addition, the structure of an existing measure assessing couple sexual scripts in response to a sexual issue was evaluated (Chapter 3). Chapter 4 examined how individuals in diverse relationships compared on measures of individual sexual script flexibility and on couple sexual scripts. Findings suggest that there are more similarities than differences across diverse couples. Chapter 5 explored how flexibility in an individual’s approach to sexual issues relates to sexual well-being, specifically by assessing sexual communication and partner responses as mediators. Results suggest that individual sexual script flexibility relates to sexual well-being through reciprocal partner processes. Collectively, this research program suggests that more similarities than differences exist between individuals in same- and mixed-gender relationships, and that partners are important to consider in the relationship between individual sexual script flexibility and sexual well-being. These findings have implications for sex and couple therapy; these results emphasize the importance of interventions that target both members of the couple, and further our understanding of sexuality in same- and mixed-gender relationships.

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Calcitic belemnite rostra are usually employed to perform paleoenvironmental studies based on geochemical data. However, several questions, such as their original porosity and microstructure, remain open, despite they are essential to make accurate interpretations based on geochemical analyses.This paper revisits and enlightens some of these questions. Petrographic data demonstrate that calcite crystals of the rostrum solidum of belemnites grow from spherulites that successively develop along the apical line, resulting in a “regular spherulithic prismatic” microstructure. Radially arranged calcite crystals emerge and diverge from the spherulites: towards the apex, crystals grow until a new spherulite is formed; towards the external walls of the rostrum, the crystals become progressively bigger and prismatic. Adjacent crystals slightly vary in their c-axis orientation, resulting in undulose extinction. Concentric growth layering develops at different scales and is superimposed and traversed by a radial pattern, which results in the micro-fibrous texture that is observed in the calcite crystals in the rostra.Petrographic data demonstrate that single calcite crystals in the rostra have a composite nature, which strongly suggests that the belemnite rostra were originally porous. Single crystals consistently comprise two distinct zones or sectors in optical continuity: 1) the inner zone is fluorescent, has relatively low optical relief under transmitted light (TL) microscopy, a dark-grey color under backscatter electron microscopy (BSEM), a commonly triangular shape, a “patchy” appearance and relatively high Mg and Na contents; 2) the outer sector is non-fluorescent, has relatively high optical relief under TL, a light-grey color under BSEM and low Mg and Na contents. The inner and fluorescent sectors are interpreted to have formed first as a product of biologically controlled mineralization during belemnite skeletal growth and the non-fluorescent outer sectors as overgrowths of the former, filling the intra- and inter-crystalline porosity. This question has important implications for making paleoenvironmental and/or paleoclimatic interpretations based on geochemical analyses of belemnite rostra.Finally, the petrographic features of composite calcite crystals in the rostra also suggest the non-classical crystallization of belemnite rostra, as previously suggested by other authors.

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Este artículo pretende demostrar en qué medida Paseo por una guerra antigua (1948-1949), la práctica de segundo curso del Instituto de Investigaciones y Experiencias Cinematográficas (IIEC) en la que Juan Antonio Bardem rueda a un joven mutilado caminando por las ruinas de la Ciudad Universitaria de Madrid, constituye un intento pionero de desmontar los relatos oficiales de la Guerra Civil Española y rescatar la memoria de los vencidos. Filmar las ruinas del campus madrileño en aquellos años era un acto sub­versivo, puesto que el Régimen había emprendido su reconstrucción para borrar las huellas del Madrid republicano y de la Guerra Civil, resignificando por completo el recinto universitario. Por tanto, en Paseo por una guerra antigua, Bardem intenta reapropiarse de un espacio que en la época iba imponiéndose como uno de los “lugares de memoria” del franquismo. Esta película se vale de la función documental del cine para inmortalizar unas ruinas que simbolizan la República y la guerra, para preservarlas de la muerte simbólica que representa su reconstrucción. Mostrar esas ruinas en 1948-1949 equivale a “materializar” el pasado, a traerlo al presente de la posguerra, en un proceso que recuerda a los planteamientos sobre la Historia de Walter Benjamin, para proponer una visión alternativa de la contienda. Se trata de una visión teñida de una memoria íntima, ya que la película es un paseo no solo por las ruinas sino también por los recuerdos de este joven mutilado. En suma, Bardem propone una contramemoria de la Guerra Civil.

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El carácter innovador y feminista del mediometraje Margarita y el lobo (1969) supuso la censura total de la película y el ostracismo hacia su directora, la entonces estudiante de la EOC, Cecilia Bartolomé. En este artículo repasamos sus anteriores cortometrajes para desgranar los primeros matices de protesta así como la utilización de la expresión musical como vehículo del discurso feminista en Margarita y el lobo. A través de los planteamientos de la musicóloga Susan McClary que abordan sexualidad, género y feminismo concluimos con una visión del análisis de género en las obras musicales, al vincular sus es­tudios al film de Bartolomé. Del mismo modo, analizamos la función que cumple la música en el medio­metraje. Para ello, examinamos el repertorio de canciones presente en Margarita y el lobo para terminar reconociendo la función discursiva y referencial como piezas claves en la película de la directora.

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This research presents Ludwig II of Baviera (1845-1886) as a historical figure and the vision of his reign theItalian director Luchino Visconti showed in his movies. This research states in an analytic and scrupulousway the relations between the historical figure, its filmic representation and the director himself. In addition,through an exhaustive research, this paper shows the aesthetics generated by directors like Visconti who reacheda remarkable peak in history of European film. Finally, this paper goes through the making of this film,which went from a transitional film within the Visconti oeuvre to one of his most troublesome and health-riskingprojects causing afterwards Visconti´s death.

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Describes and analyzes the results obtained after analysis of the publications present in Scopus data base and used that tool rankings generated by the research group Scimago on the production of the different countries of Central America on the issue of documentation the means of mass communication. Performed a comparative about different countries in the region and the scientific analyzes. Finally, and given and data analysis, a number of recommendations are made to improve the production and the presence in indexed database.

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The aim of these pages is to offer a view on the Jewish regulation of Lucena (Cordoba) in the 11th century. Through the legal texts originating from this place, which were conserved in the Cairo Genizah and later guarded at the Bodleian Library in Oxford, it is possible to observe the legal procedure of this group in relation to two essential issues: its consideration of dhimmis, due to its belonging to the ’ahl al-Kitāb or ‘people of the Book’ category, and the internal regulation of the community according to the problems emerged in it. In this article, therefore, the more frequent legal matters derived from the litigations conserved from this city until these dates will be studied.

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This paper addresses the condition of domestic work in Argentina, in a perspective that draws from the literature on care work. In this approach, domestic work can be interpreted as one of the mercantile forms in which care work is socially organized, due to the persistence of the traditional sexual division of labor and the weakness of public policies. From these considerations, I develop a quantitative study on the levels of informality, precarity, and wage inequality that characterize domestic work in that country. Thereafter, I discuss the main measures adopted by the Argentine government since 2003, with the goal of reducing legal discrimination of domestic workers and promoting their formalization. On this basis, the paper highlights the advances in the recognition of domestic workers’ labor rights, while emphasizing how social and cultural restraints still permeate labor relations in this sector.

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The neoliberal period was accompanied by a momentous transformation within the US health care system.  As the result of a number of political and historical dynamics, the healthcare law signed by President Barack Obama in 2010 ‑the Affordable Care Act (ACA)‑ drew less on universal models from abroad than it did on earlier conservative healthcare reform proposals. This was in part the result of the influence of powerful corporate healthcare interests. While the ACA expands healthcare coverage, it does so incompletely and unevenly, with persistent uninsurance and disparities in access based on insurance status. Additionally, the law accommodates an overall shift towards a consumerist model of care characterized by high cost sharing at time of use. Finally, the law encourages the further consolidation of the healthcare sector, for instance into units named “Accountable Care Organizations” that closely resemble the health maintenance organizations favored by managed care advocates. The overall effect has been to maintain a fragmented system that is neither equitable nor efficient. A single payer universal system would, in contrast, help transform healthcare into a social right.

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The article examines developments in the marketisation and privatisation of the English National Health Service, primarily since 1997. It explores the use of competition and contracting out in ancillary services and the levering into public services of private finance for capital developments through the Private Finance Initiative. A substantial part of the article examines the repeated restructuring of the health service as a market in clinical services, initially as an internal market but subsequently as a market increasing opened up to private sector involvement. Some of the implications of market processes for NHS staff and for increased privatisation are discussed. The article examines one episode of popular resistance to these developments, namely the movement of opposition to the 2011 health and social care legislative proposals. The article concludes with a discussion of the implications of these system reforms for the founding principles of the NHS and the sustainability of the service.

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Migration is as old as humanity, but since the 1990s migration flows in Western Europe have led to societies that are not just multicultural but so-called «super-diverse». As a result, Western towns now have very complex social structures, with amongst others large amounts of small immigrant communities that are in constant change. In this paper we argue that for social workers to be able to offer adequate professional help to non-native residents in town, they will need balanced view of ‘culture’ and of the role culture plays in social aid. Culture is never static, but is continually changing. By teaching social workers about how to look at cultural backgrounds of immigrant groups and about the limitations of then role that culture plays in communication, they will be better equipped to provide adequate aid and will contribute to making various groups grow towards each other and to avoid people thinking in terms of ‘out-group-homogeneity’. Nowadays, inclusion is a priority in social work that almost every social worker supports. Social workers should have an open attitude to allow them to approach every individual as a unique person. They will see the other person as the person they are, and not as a part of a specific cultural group. Knowledge about the others makes them see the cultural heterogeneity in every group. The social sector, though, must be aware not to fall into the trap of the ‘inclusion mania’! This will cause the social deprivation of a particular group to be forgotten. An inclusive policy requires an inclusive society. Otherwise, this could result in even more deprivation of other groups, already discriminated against. Emancipation of deprived people demands a certain target-group policymaking. Categorized aid will raise efficiency of working with immigrants and of acknowledging the cultural identity of the non-natives group. It will also create the possibility to work on fighting social deprivation, in which most immigrants can be found.