1,596 research outputs found
Controversial Orthodoxy: The Efficient Capital Markets Hypothesis And Loss Causation
Since the Supreme Court’s landmark holding in Basic, Inc. v. Levinson, courts have incorporated the efficient capital markets hypothesis as an analytical tool in securities fraud cases. Nevertheless, recent turmoil in the financial markets and a growing chorus of scholarship challenging traditional notions of market efficiency have caused some courts to reconsider the role of the efficient capital markets hypothesis in securities fraud litigation. This Note analyzes a question that has split the circuits and marks the intersection of market efficiency and securities fraud: how quickly must an equity security depreciate in price following the publication of a corrective disclosure for a plaintiff to plead and prove loss causation? Part I introduces the efficient capital markets hypothesis, securities fraud actions, and the ways in which courts have traditionally employed concepts of market efficiency into their analyses. Part II analyzes the circuit split regarding the speed with which the market must incorporate information into price for a plaintiff to properly plead and prove loss causation. Finally, Part III argues that courts should resist the temptation to draw bright-line rules in the context of loss causation and should engage each case on its facts by analyzing the efficiency of the relevant market during each event giving rise to the fraud and economic loss
Merging DNA metabarcoding and ecological network analysis to understand and build resilient terrestrial ecosystems
Summary 1. Significant advances in both mathematical and molecular approaches in ecology offer unprecedented opportunities to describe and understand ecosystem functioning. Ecological networks describe interactions between species, the underlying structure of communities and the function and stability of ecosystems. They provide the ability to assess the robustness of complex ecological communities to species loss, as well as a novel way of guiding restoration. However, empirically quantifying the interactions between entire communities remains a significant challenge. 2. Concomitantly, advances in DNA sequencing technologies are resolving previously intractable questions in functional and taxonomic biodiversity and provide enormous potential to determine hitherto difficult to observe species interactions. Combining DNA metabarcoding approaches with ecological network analysis presents important new opportunities for understanding large-scale ecological and evolutionary processes, as well as providing powerful tools for building ecosystems that are resilient to environmental change. 3. We propose a novel ‘nested tagging’ metabarcoding approach for the rapid construction of large, phylogenetically structured species-interaction networks. Taking tree–insect–parasitoid ecological networks as an illustration, we show how measures of network robustness, constructed using DNA metabarcoding, can be used to determine the consequences of tree species loss within forests, and forest habitat loss within wider landscapes. By determining which species and habitats are important to network integrity, we propose new directions for forest management. 4. Merging metabarcoding with ecological network analysis provides a revolutionary opportunity to construct some of the largest, phylogenetically structured species-interaction networks to date, providing new ways to: (i) monitor biodiversity and ecosystem functioning; (ii) assess the robustness of interacting communities to species loss; and (iii) build ecosystems that are more resilient to environmental change
Development and preliminary testing of a framework to evaluate patients' experiences of the fundamentals of care: a secondary analysis of three stroke survivor narratives
Aim. To develop and test a framework describing the interrelationship of three key dimensions (physical, psychosocial, and relational) in the provision of the fundamentals of care to patients. Background. There are few conceptual frameworks to help healthcare staff, particularly nurses, know how to provide direct care around fundamental needs such as eating, drinking, and going to the toilet. Design. Deductive development of a conceptual framework and qualitative analysis of secondary interview data. Method. Framework development followed by a secondary in-depth analysis of primary narrative interview data from three stroke survivors. Results. Using the physical, psychosocial and relational dimensions to develop a conceptual framework, it was possible to identify a number of “archetypes” or scenarios that could explain stroke survivors’ positive experiences of their care. Factors contributing to suboptimal care were also identified. Conclusions. This way of thinking about how the fundamentals of care are experienced by patients may help to elucidate the complex processes involved around providing high quality fundamentals of care. This analysis illustrates the multiple dimensions at play. However, more systematic investigation is required with further refining and testing with wider healthcare user groups. The framework has potential to be used as a predictive, evaluative, and explanatory tool.Alison L. Kitson and Åsa Muntlin Athli
Influence of Ethnicity, Gender and Answering Mode on a Virtual Point-to-Origin Task
In a virtual point-to-origin task, participants seem to show different response patterns and underlying strategies for orientation, such as ”turner” and ”non-turner” response patterns. Turners respond as if succeeding to update simulated heading changes, and non-turners respond as if failing to update their heading, resulting in left-right hemisphere errors. We present two other response patterns, ”non-movers” and ”spinners”, that also appear to result in failures to update heading. We have three specific goals in mind: (1) extend previous findings of higher turner rates with spatial language response mode using a point-to-origin task instead of a triangle completion task; (2) replicate the gender effect of males more likely responding as turners; (3) examine ethnicity influence. Designed as a classroom study, we presented participants (N = 498) with four passages through a virtual star field. Participants selected the direction pointing to the origin from four multiple-choice items. Response mode was either pictograms or written lan- guage, chosen to compare with similar studies and see if these response modes have an effect on virtual orientation behaviour. Results show a majority of participants (48.35%) classified as non-turners, 32.93% turners, 15.57% as non-movers, and 3.14% as spinners. A multinomial regression model reached 49% classification performance. Written spatial language, compared to pictograms, made turner response patterns more likely; this effect was more pronounced for Chinese participants and among females, but not male Caucasians. Moreover, higher turner numbers for written spatial language extends Avraamides findings of higher turner numbers when participants turned their bodies toward the origin but not when they responded verbally. Using pictorial response mode (i.e., top-down picture of a head) may have increased cognitive load because it could be considered more embodied. It remains to be seen how we can reduce the reference frame conflict that might have caused increased cognitive load. Second, our results are inconsistent with previous research in that males overall did not show more turner behaviour than females. Future research may look at possible underlying factors, such as cultural norms. Third, individualistic cultures (Caucasians) [Greif, 1994] lean towards turner response patterns, whereas collectivist cultures lean towards non-turner response patterns
Computer simulation of protein systems
Ligand binding to dihydrofolate reductase (DHFR) is discussed. This is an extremely important enzyme, as it is the target of several drugs (inhibitors) which are used clinically as antibacterials, antiprotozoals and in cancer chemotherapy. DHFR catalyzes the NADPH (reduced nicotinamide adenine dinucleotide phosphate) dependent reduction of dihydrofolate to tetrahydrofolate, which is used in several pathways of purine and pyrimidine iosynthesis, including that of thymidylate. Since DNA synthesis is dependent on a continuing supply of thymidylate, a blockade of DHFR resulting in a depletion of thymidylate can lead to the cessation of growth of a rapidly proliferating cell line. DHFR exhibits a significant species to species variability in its sensitivity to various inhibitors. For example, trimethoprim, an inhibitor of DHFR, binds to bacterial DHFR's 5 orders of magnitude greater than to vertebrate DHFR's. The structural mechanics, dynamics and energetics of a family of dihydrofolate reductases are studied to rationalize the basis for the inhibitor of these enyzmes and to understand the molecular basis of the difference in the binding constants between the species. This involves investigating the conformational changes induced in the protein on binding the ligand, the internal strain imposed by the enzyme on the ligand, the restriction of fluctuations in atom positions due to binding and the consequent change in entropy
Selective, Catalytic Decomposition of Hydrazine
The selective, catalytic decomposition of hydrazine has been investigated using a 1 wt% Pt-Ni(OH)2 catalyst system quantitatively studied by changing the following parameters; reaction solution alkalinity, temperature, hydrazine concentration, catalyst selectivity, catalyst stability, and catalyst durability. Using sodium hydroxide (NaOH), the best alkalinity was found to be 1 M NaOH. The optimal temperature was found to be 50 °C for complete hydrazine conversion. A hydrazine concentration of 0.1 M produced the most effective reaction. The catalyst was found to be completely selective in hydrogen and nitrogen production with no ammonia formation. The catalyst activity decreased by 15% after 8 days of sitting in air representing relatively poor stability, most likely due to undesired oxidation of the catalyst. Finally, the catalyst activity decreased by about 50% after subsequent, same catalyst reactions showing poor durability, resulting from a reduced number of active reaction sites. Overall, the low noble metal catalyst designed does perform the hydrazine decomposition efficiently with 100% selectivity in hydrogen and nitrogen production but needs an elevated temperature and shows signs of poor stability and durability. The cost effective catalyst could provide basis for future research to create a more stable and durable catalyst that can operate at ambient conditions
Citizens of somewhere: examining the geography of foreign and native-born academics’ engagement with external actors
This paper explores the geography of academic engagement patterns of native and foreign-born academics, contrasting how patterns of intranational and international engagement with non-academic actors differ between these two groups. We suggest that foreign-born academics will engage more internationally than their native-born colleagues, whereas native-born academics will have greater levels of intranational engagement. Drawing upon a large multi-source dataset, including a major new survey of all academics working the UK, we find support for this idea that where people are born influences how they engage with non-academic actors. We also find that these differences are attenuated by an
individual’s intranational and international experience, ethnicity and language skills. We explore the implications of these findings for policy to support intranational and international academic engagement.The Arts and Humanities Research Council, the Department for Business, Innovation & Skills, the Economic and Social Research Council, the
Engineering and Physical Sciences Research Council, the Higher Education Funding Council for England, the Medical Research Council, and the Natural Environment Research Council and the National
Centre for Universities and Business (NCUB). Cornelia Lawson received support from the University of Bath through a Prize fellowship
Topology and Bistability in liquid crystal devices
We study nematic liquid crystal configurations in a prototype bistable device
- the Post Aligned Bistable Nematic (PABN) cell. Working within the Oseen-Frank
continuum model, we describe the liquid crystal configuration by a unit-vector
field, in a model version of the PABN cell. Firstly, we identify four distinct
topologies in this geometry. We explicitly construct trial configurations with
these topologies which are used as initial conditions for a numerical solver,
based on the finite-element method. The morphologies and energetics of the
corresponding numerical solutions qualitatively agree with experimental
observations and suggest a topological mechanism for bistability in the PABN
cell geometry
Hypoxia and hyperglycaemia determine why some endometrial tumours fail to respond to metformin
High expression of Ki67, a proliferation marker, is associated with reduced endometrial cancer-specific survival. Pre-surgical metformin reduces tumour Ki-67 expression in some women with endometrial cancer. Metformin's anti-cancer activity may relate to effects on cellular energy metabolism. Since tumour hypoxia and glucose availability are major cellular redox determinants, we evaluated their role in endometrial cancer response to metformin. Endometrial cancer biopsies from women treated with pre-surgical metformin were tested for the hypoxia markers, HIF-1α and CA-9. Endometrial cancer cell lines were treated with metformin in variable glucose concentrations in normoxia or hypoxia and cell viability, mitochondrial biogenesis, function and energy metabolism were assessed. In women treated with metformin (n = 28), Ki-67 response was lower in hypoxic tumours. Metformin showed minimal cytostatic effects towards Ishikawa and HEC1A cells in conventional medium (25 mM glucose). In low glucose (5.5 mM), a dose-dependent cytostatic effect was observed in normoxia but attenuated in hypoxia. Tumours treated with metformin showed increased mitochondrial mass (n = 25), while in cultured cells metformin decreased mitochondrial function. Metformin targets mitochondrial respiration, however, in hypoxic, high glucose conditions, there was a switch to glycolytic metabolism and decreased metformin response. Understanding the metabolic adaptations of endometrial tumours may identify patients likely to derive clinical benefit from metformin
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