New Caledonian crows are the most proficient non-hominin tool manufacturers but the cognition behind their remarkable skills
remains largely unknown. Here we investigate if they attend to the functional properties of the tools that they routinely
use in the wild. Pandanus tools have natural barbs along one edge that enable them to function as hooking implements when
the barbs face backwards from the working tip. In experiment 1 we presented eight crows with either a non-functional (‘upside-down’)
or a functional pandanus tool in a baited hole. Four of the crows never flipped the tools. The behaviour of the four flipping
birds suggested that they had a strategy of flipping a tool when it was not working. Observations of two of the eight crows
picking up pandanus tools at feeding tables in the wild supported the lack of attention to barb direction. In experiment 2
we gave six of the eight crows a choice of either a barbed or a barbless pandanus tool. Five of the crows chose tools at random,
which further supported the findings in experiment 1 that the crows paid little or no attention to the barbs. In contrast,
a third experiment found that seven out of eight crows flipped non-functional stick tools significantly more than functional
ones. Our findings indicate that the crows do not consistently attend to the presence or orientation of barbs on pandanus
tools. Successful pandanus tool use in the wild seems to rely on behavioural strategies formed through associative learning,
including procedural knowledge about the sequence of operations required to make a successful pandanus tool.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Recent attempts to medicalize women’s sexual “dysfunction” are critiqued and a “New View” of women’s sexual problems is introduced. The author argues for a female-centered perspective on women’s sexual desires and problems, based on a review of the literature on women’s sexuality and her observations of young women’s sexual experiences from 25 years of teaching Human Sexuality to undergraduate women. The review suggests that a pill or a patch cannot adequately address the sexual problems commonly experienced by US women. 相似文献
This paper presents Automath encodings (which are also valid in LF/λP) of various kinds of foundations of mathematics. Then it compares these encodings according to their size, to find out which foundation is the simplest.
The systems analyzed in this way are two kinds of set theory (ZFC and NF), two systems based on Church's higher order logic (Isabelle/Pure and HOL), three kinds of type theory (the calculus of constructions, Luo's extended calculus of constructions, and Martin-Löf's predicative type theory) and one foundation based on category theory.
The conclusions of this paper are that the simplest system is type theory (the calculus of constructions), but that type theories that know about serious mathematics are not simple at all. In that case the set theories are the simplest. If one looks at the number of concepts needed to explain such a system, then higher order logic is the simplest, with twenty-five concepts. On the other side of the scale, category theory is relatively complex, as is Martin-Löf's type theory.
(The full Automath sources of the contexts described in this paper are one the web at http://www.cs.ru.nl/~freek/zfc-etc/.) 相似文献
In this paper, we describe a design study on how families in Los Angeles experience nature, with a particular focus on how
using alternative formats for research analysis and presentation can enrich a design research inquiry. Conducted in Pasadena,
CA as a part of Super Studio, the year-long design research class emphasized knowledge building and sharing through design
methods of analysis, exhibition, and concept prototypes. After conducting interviews and engaging participants with probes,
the class built the results into an open-ended knowledge environment. The main observation from the exhibition – that Angelenos
have a limited vocabulary for describing nature and their interaction with it – helped to define the opportunity for design
intervention that created connection points between Angelenos and nature. There are few attempts to describe how probe returns
evolve into design concepts. Showcased is a process that depends on the unique affordances of design as the vehicle for discovery
and invention. 相似文献
Using the socialization and attraction-selection-attrition (ASA) frameworks, this study examined the relation between employees’ work values and their organization’s values (person-organization fit). With a two year time interval, 140 respondents participated in a longitudinal study. After entry, socialization served to enhance homogeneity. The work values underwent small changes and the perception of fit with the organization grew. Despite high retention rates results confirmed the attrition effect. Results indicated that the lower the perceived match between own and organizational values at entry, the more likely it was that someone left the organization over time. We concluded that socialization as well as attrition mechanisms were present at the same time. 相似文献
Using the example of the Catholic Church in Papua New Guinea (PNG), I detail how, through praxis, it has brought to life a
living theology of HIV and AIDS. In this way, the Catholic Church in PNG is responding faithfully to the epidemic. As a Christian
country with a generalised HIV epidemic, where the body of an individual is reconstituted through the liturgical practices
of baptism and Eucharist, theologically, in PNG the body of Christ has AIDS. In order to examine the ways in which the Catholic
Church in PNG has responded faithfully to the Christian body with AIDS, I do so in relation to the three theological virtues
of faith, hope and love.
There might not be a specific nano-ethics, but there definitely is an ethics of new & emerging science and technology (NEST),
with characteristic tropes and patterns of moral argumentation. Ethical discussion in and around nanoscience and technology
reflects such NEST-ethics. We offer an inventory of the arguments, and show patterns in their evolution, in arenas full of
proponents and opponents. We also show that there are some nano-specific issues: in how size matters, and when agency is delegated
to smart devices. Our overall approach is a pragmatist ethics, and we conclude that struggle (and learning) might be more
productive than models emphasizing consensus.
This study examined the role of media body comparison as a mediator of the relationships between psychological factors and sociocultural pressures to be thin and body dissatisfaction in both females and males. Participants were 1,386 females (mean age = 19.37 years) and 1,130 males (mean age = 19.46) from diverse backgrounds who completed a self-report questionnaire. Path analysis was used to test a cross-sectional model in which media body comparison mediated the impact of self-esteem, depressive mood, parent dieting environment, friend dieting, TV exposure, magazine message exposure, weight teasing and body mass index (BMI) on body dissatisfaction. In females, media body comparison partially or fully mediated relationships between self-esteem, depressive mood, friend dieting, magazine message exposure and BMI, and body dissatisfaction. In males, media body comparison was not a significant predictor of body dissatisfaction. This research particularly highlights the need to further examine processes that are involved in the development of body dissatisfaction in males. 相似文献