Static theory of the giant quadrupole resonance in deformed nuclei

The modes and frequencies of the giant quadrupole resonance of heavy deformed nuclei have been calculated. The quadrupole operator is computed and the absorption cross section is derived. The quadrupole sum rule is discussed, and the relevant oscillator strengths have been evaluated for various orientations of the nucleus. The giant quadrupole resonances have energies between 20 and 25 MeV. The total absorption cross section is about 20% of the giant dipole absorption cross section. Of particular interest is the occurrence of the quadrupole mode which is sensitive to the nuclear radius in a direction of approximately θ=(1/4)π from the symmetry axis. This may give information on the details of the nuclear shape

Active Discriminative Text Representation Learning

We propose a new active learning (AL) method for text classification with convolutional neural networks (CNNs). In AL, one selects the instances to be manually labeled with the aim of maximizing model performance with minimal effort. Neural models capitalize on word embeddings as representations (features), tuning these to the task at hand. We argue that AL strategies for multi-layered neural models should focus on selecting instances that most affect the embedding space (i.e., induce discriminative word representations). This is in contrast to traditional AL approaches (e.g., entropy-based uncertainty sampling), which specify higher level objectives. We propose a simple approach for sentence classification that selects instances containing words whose embeddings are likely to be updated with the greatest magnitude, thereby rapidly learning discriminative, task-specific embeddings. We extend this approach to document classification by jointly considering: (1) the expected changes to the constituent word representations; and (2) the model's current overall uncertainty regarding the instance. The relative emphasis placed on these criteria is governed by a stochastic process that favors selecting instances likely to improve representations at the outset of learning, and then shifts toward general uncertainty sampling as AL progresses. Empirical results show that our method outperforms baseline AL approaches on both sentence and document classification tasks. We also show that, as expected, the method quickly learns discriminative word embeddings. To the best of our knowledge, this is the first work on AL addressing neural models for text classification.Comment: This paper got accepted by AAAI 201

Situating Environmental Philosophy in Canada

The volume includes topics from political philosophy and normative ethics on the one hand to philosophy of science and the philosophical underpinnings of water management policy on the other. It contains reflections on ecological nationalism, the legacy of Grey Owl, the meaning of ‘outside’ to Canadians, the paradigm shift from mechanism to ecology in our understanding of nature, the meaning of the concept of the Anthropocene, the importance of humans self-identifying as ‘earthlings’, the challenges of biodiversity protection and the status of cross-bred species, how to ground the moral considerability of ecosystems, the collapse of the Newfoundland and Labrador cod fishery, and much more. It covers metaphysics, ontology, ethics, political philosophy, critical history, and environmental policy. The range of topics and frames is as diverse and challenging as the land itself

Dynamic collective theory of odd-a nuclei

The unified model and the collective giant-dipole-resonance model are unified. The resulting energy spectrum and the transition probabilities are derived. A new approximate selection rule involving the symmetry of the γ vibrations is established. It is verified that the main observable features in the photon-absorption cross section are not influenced by the odd particle, despite the considerably richer spectrum of states as compared to even-even nuclei

Origin of Spin Ice Behavior in Ising Pyrochlore Magnets with Long Range Dipole Interactions: an Insight from Mean-Field Theory

Recent experiments suggest that the Ising pyrochlore magnets ${\rm Ho_{2}Ti_{2}O_{7}}$ and ${\rm Dy_{2}Ti_{2}O_{7}}$ display qualitative properties of the ferromagnetic nearest neighbor spin ice model proposed by Harris {\it et al.}, Phys. Rev. Lett. {\bf 79}, 2554 (1997). The manifestation of spin ice behavior in these systems {\it despite} the energetic constraints introduced by the strength and the long range nature of dipole-dipole interactions, remains difficult to understand. We report here results from a mean field analysis that shed some light on the origin of spin ice behavior in (111) Ising pyrochlores. Specifically, we find that there exist a large frustrating effect of the dipolar interactions beyond the nearest neighbor, and that the degeneracy established by effective ferromagnetic nearest neighbor interactions is only very weakly lifted by the long range interactions. Such behavior only appears beyond a cut-off distance corresponding to $O(10^2)$ nearest neighbor. Our mean field analysis shows that truncation of dipolar interactions leads to spurious ordering phenomena that change with the truncation cut-off distance.Comment: 7 Color POSTSCRIPT figures included. To appear in Canadian Journal of Physics for the Proceedings of the {\it Highly Frustrated Magnetism 2000 Conference}, Waterloo, Ontario, Canada, June 11-15, 2000 Contact: [email protected]

Is greater decisionmaking power of women associated with reduced gender discrimination in South Asia?

"Recent research has shown that improving women's decisionmaking power relative to men's within households leads to improvements in a variety of well-being outcomes for children. In South Asia, where the influence of women's power is particularly strong, these outcomes include children's nutritional status and the quality of feeding and health care practices. Focusing on nutritional status, this paper presents the results of a study investigating whether increases in women's power have a stronger positive influence on the nutritional status of their daughters than their sons. If so, then increasing women's power not only improves the well-being of children as a group, but also serves as a force to reduce long-standing discrimination that undermines female capabilities in many important areas of life as well as human and economic development in general. To investigate this issue, the study draws on Demographic and Health Survey data collected during the 1990s in four countries: Bangladesh, India, Nepal, and Pakistan. The main empirical technique employed is multivariate regression analysis with statistical tests for significant differences in effects for girl and boy children. A total of 30,334 women and 33,316 children under three years old are included in the analysis. The study concludes that, for the South Asia region as a whole, an increase in women's decisionmaking power relative to men's, if substantial, would be an effective force for reducing discrimination against girl children. However, this finding is not applicable in all countries and for all areas and age groups of children. Indeed the study finds evidence that in some areas, for instance the northern and western states of India as a group, increasing women's power would lead to a worsening of gender discrimination against girls. This is likely the result of deeply embedded son preference associated with highly patriarchal social systems. The lesson for policymakers and development practitioners is that while increasing women's power is likely to improve the well-being of children, in some geographical areas it will not necessarily diminish discrimination against girls, which violates human rights and undermines the region's economic development and the health of its population. In these areas, to overcome son preference, economic returns to girls will have to be increased and efforts to change customs regarding marriage and inheritance associated with patriarchal kinship systems, which favor males, will have to be made." Authors' AbstractGender discrimination ,Women Social conditions ,Children Nutrition ,Economic development ,

Neuregulin 1-Beta cytoprotective role in AML 12 mouse hepatocytes exposed to pentachlorophenol.

Neuregulins are a family of growth factor domain proteins that are structurally related to the epidermal growth factor. Accumulating evidence has shown that neuregulins have cyto- and neuroprotective properties in various cell types. In particular, the neuregulin-1 Beta (NRG1-Beta) isoform is well documented for its antiinflammatory properties in rat brain after acute stroke episodes. Pentachlorophenol (PCP) is an organochlorine compound that has been widely used as a biocide in several industrial, agricultural, and domestic applications. Previous investigations from our laboratory have demonstrated that PCP exerts both cytotoxic and mitogenic effects in human liver carcinoma (HepG2) cells, primary catfish hepatocytes and AML 12 mouse hepatocytes. We have also shown that in HepG2 cells, PCP has the ability to induce stress genes that may play a role in the molecular events leading to toxicity and tumorigenesis. In the present study, we hypothesize that NRG1-Beta will exert its cytoprotective effects in PCP-treated AML 12 mouse hepatocytes by its ability to suppress the toxic effects of PCP. To test this hypothesis, we performed the MTT-cell respiration assay to assess cell viability, and Western-blot analysis to assess stress-related proteins as a consequence of PCP exposure. Data obtained from 48 h-viability studies demonstrated a biphasic response; showing a dose-dependent increase in cell viability within the range of 0 to 3.87 microg/mL, and a gradual decrease within the concentration range of 7.75 to 31.0 microg/mL in concomitant treatments of NRG1-Beta+PCP and PCP. Cell viability percentages indicated that NRG1-Beta+PCPtreated cells were not significantly impaired, while PCP-treated cells were appreciably affected; suggesting that NRG1-Beta has the ability to suppress the toxic effects of PCP. Western Blot analysis demonstrated the potential of PCP to induce oxidative stress and inflammatory response (c-fos), growth arrest and DNA damage (GADD153), proteotoxic effects (HSP70), cell cycle arrest as consequence of DNA damage (p53), mitogenic response (cyclin- D1), and apoptosis (caspase-3). NRG1-Beta exposure attenuated stress-related protein expression in PCP-treated AML 12 mouse hepatocytes. Here we provide clear evidence that NRG1-Beta exerts cytoprotective effects in AML 12 mouse hepatocytes exposed to PCP