1,762 research outputs found
Spread of retailer food quality standards: an international perspective
Privately initiated food quality standards are currently important elements in the marketing of food and agricultural products. At the same time, they stand in the centre of a discussion about potential negative effects on small farmers and farmers in developing countries. This study aims at analysing the adoption of two private food standards, BRC Technical Food Standard and GlobalGAP, at an aggregated crosscountry level. The results of the econometric analysis reveal some (potential) barriers for developing countries to access this type of organisational innovation. Certificates seem to be issued more probably in larger and wealthier countries, countries with a better institutional quality, better infrastructural conditions and in former UK colonies
Suggestions for Genetic A.I.
This paper presents suggestions for "Genetic A.I.": an attempt to model the genesis of intelligence in human infants, particularly as described by Piaget's theory of the Sensorimotor period. The paper includes a synopsis of Sensorimotor intelligence, followed by preliminary suggestions for a mechanism (the "Schema mechanism") for its development, and a hypothetical Scenario which partially reinterprets Sensorimotor development in terms of that mechanism.
The Schema mechanism focuses on Piaget's concept of the competition and evolution of mental "schemas." The schema is modelled here as an assertion that one partial state of the mechanism's world-representation is transformable to another via a given action, taken when the schema is "activated". A proposed process of "correlation" allows a schema's assertion to be extended or revised in response to empirically-observed effects of the schema's activation. Correlation uses the the formation and activation of schemas to propose and test hypothesis, in contrast with the passive tabulation characteristic of associationist mechanisms. Further features are proposed to enable schemas to become coordinated into composite structures, "compound actions", which can be used by other schemas; and to synthesize new "items" (state-elements) when existing ones prove inadequate to model the world.
The Scenario outlines how the Schema mechanism might begin to make its way through the progression of Sensorimotor stages; development culminating in Piaget's third stage is discussed. This development includes learning about the visual and tactile effects of eye and hand motions-- eg, learning how to look directly at an object, or to move a hand into view; and the organization of that knowledge to designate the tactile properties of "visual objects", and vice versa-- eg knowing how to touch an object which is seen-- paving the way to a sensory-modality-invariant representation of objects and space.
The Schema mechanism attempts to "learn from scratch", without built-in expertise or built-in structure in its learning domains. In the past there has been little success among AI programs of this genre. But many such attempts have suffered from mechanisms which were trivial in that they placed the full burden of acquiring and structuring knowledge on one or two simple tricks, whereas, I claim, the present effort shows a willingness to incorporate a multiplicity of elements in a complicated mechanism. In addition, the Schema mechanism benefits from its orientation around a nontrivial theory of development. Piaget gives a comprehensive account of the infant's evolution of primitive problem-solving and domain-specific (chiefly object-manipulation) knowledge; this account is used here as a roadmap that describes the proper course for the mechanism to follow. Thus, there is a nontrivial (or at least nonarbitrary) sequence of target abilities to use as a framework for evaluating and revising the mechanism's performance.MIT Artificial Intelligence Laborator
Academic Librarians\u27 Opinions on Social Justice Advocacy
This session presented the results of 113 academic librarians surveyed regarding their views on social justice advocacy. As part of a mixed-methods exploration, quantitative, qualitative, and integrated elements were revealed. Beyond a comprehensive survey administered, librarian advocates describe how they approach issues of social justice, what the benefits are of addressing inequities within academic libraries, what barriers they\u27ve encountered in their advocacy efforts and initiatives, and what advice a more experienced advocate might offer to a peer with less knowledge who is interested in becoming more involved
Academic Librarians\u27 Opinions on Social Justice Advocacy
This session will reveal the results of 113 academic librarians surveyed regarding their views on social justice advocacy. As part of a mixed-methods exploration, both quantitative and qualitative elements will be explored. Beyond a comprehensive survey administered, librarian advocates describe how they approach issues of social justice, what the benefits are of addressing inequities within academic libraries, what barriers they\u27ve encountered in their advocacy efforts and initiatives, and what advice a more experienced advocate might offer to a peer with less knowledge who is interested in becoming more involved
Toward a Transdisciplinary Model of Social Justice in Academic Librarianship: Promoting Critical Awareness within Advocates and Privileged Allies
Academic libraries are largely comprised of White, middle-aged females, and as part of the overall diversity crisis within higher education, grapple with issues of racism, sexism, heterosexism, classism, and ableism. This mixed-methods study uses an original theoretical framework of critical transcendence, based on the philosophies of Carl Jung and Paulo Freire, to examine what triggers and/or preconditions lead some academic librarians to reflect upon and interrogate their worldview to become actively engaged as advocates and social justice allies (SJAs). An online survey was conducted that obtained data from a sample of 113 academic librarians regarding their interest and commitment toward advocating for social justice and found a significant positive correlation between social justice interest and social justice commitment. Qualitative and mixed analysis included a thematic review of several open-ended questions (OeQs) as well as interviews with six academic librarians who self-identified as SJAs in the quantitative phase. Collective themes emerging from the narratives indicated librarians believed it was a culmination of environment, education, and experience that led them to become SJAs. Strategies they found most impactful were directly engaging with marginalized and underrepresented groups, creating external pathways to success for students and staff, and forming alliances with like-minded allies. When applicable, narrative results were dovetailed with the OeQs to gain a holistic understanding of why academic librarians choose to advocate for social justice. Thus, by examining multiple aspects of the phenomenon, my work provides greater insight as to the motivational factors for social justice advocates and allies within academic libraries and beyond
Resistência à penetração e rendimento da soja após intervenção mecânica em latossolo vermelho sob plantio direto.
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How to Track Protists in Three Dimensions
We present an apparatus optimized for tracking swimming microorganisms in the
size range 10-1000 microns, in three dimensions (3D), far from surfaces, and
with negligible background convective fluid motion. CCD cameras attached to two
long working distance microscopes synchronously image the sample from two
perpendicular directions, with narrowband dark-field or bright-field
illumination chosen to avoid triggering a phototactic response. The images from
the two cameras can be combined to yield 3D tracks of the organism. Using
additional, highly directional broad-spectrum illumination with millisecond
timing control the phototactic trajectories in 3D of organisms ranging from
Chlamydomonas to Volvox can be studied in detail. Surface-mediated hydrodynamic
interactions can also be investigated without convective interference. Minimal
modifications to the apparatus allow for studies of chemotaxis and other taxes.Comment: 8 pages, 7 figure
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Attosecond transient absorption spectroscopy without inversion symmetry
Transient absorption is a very powerful observable in attosecond experiments on atoms, molecules and solids and is frequently used in experiments employing phase-locked few-cycle infrared and XUV laser pulses derived from high harmonic generation. We show numerically and analytically that in non-centrosymmetric systems, such as many polyatomic molecules, which-way interference enabled by the lack of parity conservation leads to new spectral absorption features, which directly reveal the laser electric field. The extension of attosecond transient absorption spectroscopy (ATAS) to such targets hence becomes sensitive to global and local inversion symmetry. We anticipate that ATAS will find new applications in non-centrosymmetric systems, in which the carrier-to-envelope phase of the infrared pulse becomes a relevant parameter and in which the orientation of the sample and the electronic symmetry of the molecule can be addressed. © 2020 The Author(s). Published by IOP Publishing Ltd
Attosecond transient absorption spectroscopy without inversion symmetry
Transient absorption is a very powerful observable in attosecond experiments on atoms, molecules and solids and is frequently used in experiments employing phase-locked few-cycle infrared and XUV laser pulses derived from high harmonic generation. We show numerically and analytically that in non-centrosymmetric systems, such as many polyatomic molecules, which-way interference enabled by the lack of parity conservation leads to new spectral absorption features, which directly reveal the laser electric field. The extension of attosecond transient absorption spectroscopy (ATAS) to such targets hence becomes sensitive to global and local inversion symmetry. We anticipate that ATAS will find new applications in non-centrosymmetric systems, in which the carrier-to-envelope phase of the infrared pulse becomes a relevant parameter and in which the orientation of the sample and the electronic symmetry of the molecule can be addressed
Kieferorthopädische Behandlungselemente aus pseudoelastischen Nickel-Titan-Memory-Legierungen - Finite Elemente Modellierung, experimentelle Verifizierung und klinischer Einsatz
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