1,618 research outputs found
Childrenâs preference for HAS and LOCATED relations: A word learning bias for nounânoun compounds
The present study investigates childrenâs bias when interpreting novel nounânoun compounds (e.g. kig donka) that refer to combinations of novel objects (kig and donka). More specifically, it investigates childrenâs understanding of modifierâhead relations of the compounds and their preference for HAS or LOCATED relations (e.g. a donka that HAS a kig or a donka that is LOCATED near a kig) rather than a FOR relation (e.g. a donka that is used FOR kigs). In a forced-choice paradigm, two- and three-year-olds preferred interpretations with HAS/LOCATED relations, while five-year-olds and adults showed no preference for either interpretation. We discuss possible explanations\ud
for this preference and its relation to another word learning bias that is based on perceptual features of the referent objects, i.e. the shape bias. We argue that children initially focus on a perceptual stability rather than a pure conceptual stability when interpreting the meaning of nouns
Matrix String Theory and its Moduli Space
The correspondence between Matrix String Theory in the strong coupling limit
and IIA superstring theory can be shown by means of the instanton solutions of
the former. We construct the general instanton solutions of Matrix String
Theory which interpolate between given initial and final string configurations.
Each instanton is characterized by a Riemann surface of genus h with n
punctures, which is realized as a plane curve. We study the moduli space of
such plane curves and find out that, at finite N, it is a discretized version
of the moduli space of Riemann surfaces: instead of 3h-3+n its complex
dimensions are 2h-3+n, the remaining h dimensions being discrete. It turns out
that as tends to infinity, these discrete dimensions become continuous, and
one recovers the full moduli space of string interaction theory.Comment: 30 pages, LaTeX, JHEP.cls class file, minor correction
E pluribus unum : impact entrepreneurship as a solution to grand challenges
Insufficiency of research and theory on the relationship between entrepreneurship and grand challenges means that we know little about who engages and what repertoires of actions they take to tackle socioenvironmental challenges that transcend firms, markets, and nations, and what sorts of solutions they create. Drawing on the five articles featured in this symposium-and focusing especially on their protagonists or actors, the actions these actors take, and their achievements-we begin to conceptualize an impact entrepreneurship perspective. Following the tenet of e pluribus unum ("out of many, one") and adhering to the doctrine that diverse, decentralized human effort can improve the world, our impact entrepreneurship perspective refers to the development of solutions to grand challenges, in a financially, socially, and environmentally sustainable fashion. All in all, then, this symposium provides a starting point to discuss, conceptualize, study, interpret, and enrich our understanding of impact entrepreneurship and collective action to address grand challenges
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Loss of testosterone impairs anti-tumor neutrophil function.
In men, the incidence of melanoma rises rapidly after age 50, and nearly two thirds of melanoma deaths are male. The immune system is known to play a key role in controlling the growth and spread of malignancies, but whether age- and sex-dependent changes in immune cell function account for this effect remains unknown. Here, we show that in castrated male mice, neutrophil maturation and function are impaired, leading to elevated metastatic burden in two models of melanoma. Replacement of testosterone effectively normalized the tumor burden in castrated male mice. Further, the aberrant neutrophil phenotype was also observed in prostate cancer patients receiving androgen deprivation therapy, highlighting the evolutionary conservation and clinical relevance of the phenotype. Taken together, these results provide a better understanding of the role of androgen signaling in neutrophil function and the impact of this biology on immune control of malignancies
String Interactions from Matrix String Theory
The Matrix String Theory, i.e. the two dimensional U(N) SYM with N=(8,8)
supersymmetry, has classical BPS solutions that interpolate between an initial
and a final string configuration via a bordered Riemann surface. The Matrix
String Theory amplitudes around such a classical BPS background, in the strong
Yang--Mills coupling, are therefore candidates to be interpreted in a stringy
way as the transition amplitude between given initial and final string
configurations. In this paper we calculate these amplitudes and show that the
leading contribution is proportional to the factor g_s^{-\chi}, where \chi is
the Euler characteristic of the interpolating Riemann surface and g_s is the
string coupling. This is the factor one expects from perturbative string
interaction theory.Comment: 15 pages, 2 eps figures, JHEP Latex class, misprints correcte
Skeletonized internal thoracic artery harvesting reduces chest wall dysesthesia after coronary bypass surgery
ObjectiveA pain syndrome related to intercostal nerve injury during internal thoracic artery harvesting causes significant morbidity after coronary bypass surgery. We hypothesized that its incidence and severity might be reduced by using skeletonized internal thoracic artery harvesting rather than pedicled harvesting.MethodsIn a prospective double-blind clinical trial, 41 patients undergoing coronary bypass were randomized to receive either unilateral pedicled or skeletonized internal thoracic artery harvesting. Patients were assessed 7 (early) and 21 (late) weeks postoperatively with reproducible sensory stimuli used to detect chest wall sensory deficits (dysesthesia) and with a pain questionnaire used to assess neuropathic pain.ResultsAt 7 weeks postoperatively, the area of harvest dysesthesia (percentage of the chest) in the skeletonized group (n = 21) was less (median, 0%; interquartile range, 0â0) than in the pedicled group (n = 20) (2.8% [0â13], P = .005). The incidence of harvest dysesthesia at 7 weeks was 14% in the skeletonized group versus 50% in the pedicled group (P = .02). These differences were not sustained at 21 weeks, as the median area of harvest dysesthesia in both groups was 0% (P = .89) and the incidence was 24% and 25% in the skeletonized and pedicled groups, respectively (P = 1.0). The incidence of neuropathic pain in the skeletonized group compared with the pedicled group was 5% versus 10% (P = .6) at 7 weeks and 0% versus 0% (P = 1.0) at 21 weeks.ConclusionsCompared with pedicled harvesting, skeletonized harvesting of the internal thoracic artery provides a short-term reduction in the extent and incidence of chest wall dysesthesia after coronary bypass, consistent with reduced intercostal nerve injury and therefore the reduced potential for neuropathic chest pain
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Semantic memory redux: an experimental test of hierarchical category representation
Four experiments investigated the classic issue in semantic memory of whether people organize categorical information in hierarchies and use inference to retrieve information from them, as proposed by Collins & Quillian (1969). Past evidence has focused on RT to confirm sentences such as âAll birds are animalsâ or âCanaries breathe.â However, confounding variables such as familiarity and associations between the terms have led to contradictory results. Our experiments avoided such problems by teaching subjects novel materials. Experiment 1 tested an implicit hierarchical structure in the features of a set of studied objects (e.g., all brown objects were large). Experiment 2 taught subjects nested categories of artificial bugs. In Experiment 3, subjects learned a tree structure of novel category hierarchies. In all three, the results differed from the predictions of the hierarchical inference model. In Experiment 4, subjects learned a hierarchy by means of paired associates of novel category names. Here we finally found the RT signature of hierarchical inference. We conclude that it is possible to store information in a hierarchy and retrieve it via inference, but it is difficult and avoided whenever possible. The results are more consistent with feature comparison models than hierarchical models of semantic memory
Medical Student Mistreatment: Understanding \u27Public Humiliation\u27
Introduction: Mistreatment in medical school is an enduring problem in medical education. Little is known about the concept of âpublic humiliation,â one of the most common forms of mistreatment as identified on the AAMC Graduation Questionnaire. The objective of this study was to further investigate âpublic humiliationâ and to understand the underpinnings and realities of âpublic humiliationâ in medical education. Method: Focus groups of medical students on clinical rotation at the University of Washington School of Medicine were conducted over one and a half years. Qualitative analysis of responses identified emergent themes. Results: Study results included responses from 28 third year and one fourth-year medical student obtained over five different focus groups. Participants defined the term âpublic humiliationâ as negatively, purposefully induced embarrassment. Risk factors for the experience of public humiliation in educational settings were found to include the perceived intent and tone of the teacher, as well as situations being âpublicâ to patients and taking place during a medical or surgical procedure. Socratic teaching or âpimpingâ was not found to be a risk factor as long as learners were properly oriented to the teaching practice. Discussion: This study investigated and defined âpublic humiliationâ in the setting of medical student mistreatment. More subtle forms of mistreatment, like public humiliation, may be amenable to interventions focused on teaching educators about the importance of orientation and clear communication of intent during the teaching process
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