869 research outputs found
Filling Essential Laminations
Thurston and, later, Calegari-Dunfield found superlaminations in certain laminated 3-manifolds, the existence of which implies inclusions into Homeo S1 of the fundamental groups of those manifolds. The present paper extends the construction of the superlamination, and finds an infinite class of manifolds to which the extension does not yield such an inclusion of groups. Specifically, Calegari and Dunfield\u27s proof of the existence of such an inclusion into Homeo S1 depended on their filling lemma, which states that essential laminations with solid torus guts can have leaves added to them to yield essential laminations with solid torus complementary regions.: Roughly, a gut is that part of a complementary region that is not sandwiched between only two leaves.) The present paper finds the leafspace of the resultant lamination, and extends Calegari and Dunfield\u27s operation to more general cases: first to reduce any finite-genus-handlebody complementary region to its gut, and then to reduce the genus of a complementary region even where doing so modifies the gut itself. In these cases, too, then, there can be an inclusion of the manifold\u27s fundamental group into Homeo S1. Cataclysms correspond to non-Hausdorffness in the leafspace of a lamination. A cataclysm is orderable if some order on it is invariant under deck transformations. Calegari-Dunfield showed that orderability of cataclysms, which is weaker than Hausdorffness of the leafspace, is sufficient for the existence of an inclusion into Homeo S1. The present paper finds a criterion for the non-orderability of cataclysms, and a class of examples satisfying the criterion
SALES RESPONSES TO RECALLS FOR LISTERIA MONOCYTOGENES: EVIDENCE FROM BRANDED READY-TO-EAT MEATS
Empirical models are used to measure sales losses experienced by frankfurter brands following a recall for a foodborne pathogen. Recalled brands experience a 22 to 27 percent sales decline after a recall. Brand recovery occurs within 4 to 5 months after a recall. Non-recalled brands do not experience sales losses.Food Consumption/Nutrition/Food Safety,
Consumer Preferences for Pasture-Raised Animal Products: Results from Michigan
The pasture-based model of agriculture potentially offers opportunities for small- and medium-scale livestock producers in local, regional, and national markets. Our data indicate that many consumers value the attributes associated with locally produced pasture-raised products. We used ordered probit and binary probit analyses of these data to identify the demographic segments that showed the greatest interest in these attributes. This interest suggests a broad education and marketing effort to articulate salient attributes and to differentiate and increase the availability of these products in the marketplace.Demand and Price Analysis, Livestock Production/Industries,
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Can recidivism be predicted among rapists and pedophiles during their first year of parole in the state of California?
A multi-regression analysis was performed utilizing the variables, age, ethnicity, criminal background, and facets of treatment, but differentiated between the rapist and pedophile, examining the variance of recidivism
Vibrational couplings between protein and cofactor in bacterial phytochrome Agp1 revealed by 2D-IR spectroscopy
Significance
Two-dimensional infrared absorption (2D-IR) spectroscopy is severely limited in its application to larger proteins due to broad and overlapping signals in the amide I region. Here, we overcome this limitation and isolate couplings between pairwise two single-molecular groups in the biotechnologically relevant phytochrome Agp1 (510 aa) by calculating light-induced difference spectra. In phytochromes, the photoactivation of a cofactor with a relatively small structural change triggers a large-scale refolding of big parts of the protein, but the mechanism of that interaction is not understood. We observe cross-peaks in the 2D-IR spectra that are directly related to the changing dipole coupling between the cofactor and the part of the protein that refolds, suggesting that both sites stabilize each other mutually.
Abstract
Phytochromes are ubiquitous photoreceptor proteins that undergo a significant refolding of secondary structure in response to initial photoisomerization of the chromophoric group. This process is important for the signal transduction through the protein and thus its regulatory function in different organisms. Here, we employ two-dimensional infrared absorption (2D-IR) spectroscopy, an ultrafast spectroscopic technique that is sensitive to vibrational couplings, to study the photoreaction of bacterial phytochrome Agp1. By calculating difference spectra with respect to the photoactivation, we are able to isolate sharp difference cross-peaks that report on local changes in vibrational couplings between different sites of the chromophore and the protein. These results indicate inter alia that a dipole coupling between the chromophore and the so-called tongue region plays a role in stabilizing the protein in the light-activated state
Prostate lymphoscintigraphy and radio-guided surgery for sentinel lymph node identification in prostate cancer - Technique and results of the first 350 cases
Introduction: Having in mind the promising results of lymphoscintigraphy and intraoperative gamma probe application for the detection of sentinel lymph nodes (SLN) in malignant melanoma, breast and penis cancer, we tried to identify the SLN in prostate cancer by applying a comparable technique. Materials and Method. 350 patients with prostate cancer were examined after providing informed consent. The day before pelvic lymphadenectomy technetium-99m nanocolloid was transrectally injected into the prostate under ultrasound guidance. A single central application was done per prostate lobe in most cases. Activity attained 90400 MBq, and the total injected volume was about 2-3 ml. Hereafter, lymphoscintigraphy was carried out. Those lymph nodes having been identified as SLN by means of gamma probe detection and lymphoscintigraphy were removed intraoperatively. Later, most of the cases had different types of pelvic lymphadenectomy. SLN received serial sections and immunohistochemistry, non-SLN step sections. Results: 335 patients showed at least 1 SLN in lymphoscintigraphy. 24.7% had lymph node metastases. In 2 patients, metastases in non-SLN were found without at least one SLN being affected (false-negative patient). Conclusion:Our experience suggests that the SLN identification is not only feasible in breast cancer and malignant melanoma, but also in prostate cancer with a comparable technique. Copyright (C) 2003 S. Karger AG, Basel
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Reliable and Elastic Propagation of Cortical Seizures In Vivo
Mapping the fine-scale neural activity that underlies epilepsy is key to identifying potential control targets of this frequently intractable disease. Yet, the detailed in vivo dynamics of seizure progression in cortical microcircuits remain poorly understood. We combine fast (30-Hz) two-photon calcium imaging with local field potential (LFP) recordings to map, cell by cell, the spread of locally induced (4-AP or picrotoxin) seizures in anesthetized and awake mice. Using single-layer and microprism-assisted multilayer imaging in different cortical areas, we uncover reliable recruitment of local neural populations within and across cortical layers, and we find layer-specific temporal delays, suggesting an initial supra-granular invasion followed by deep-layer recruitment during lateral seizure spread. Intriguingly, despite consistent progression pathways, successive seizures show pronounced temporal variability that critically depends on GABAergic inhibition. We propose an epilepsy circuit model resembling an elastic meshwork, wherein ictal progression faithfully follows preexistent pathways but varies flexibly in time, depending on the local inhibitory restraint
Community-Based Food Systems in Michigan: Cultivating Diverse Collaborations from the Ground Up
This article discusses the results of a Michigan project to forge partnerships between Extension and diverse teams of community members to enhance development of local food systems. The project provided training and resources for teams to utilize food system work as a community problem solving tool. Such efforts have great potential to address a host of public health, economic, and land use issues
Explanation matters:An experimental study on explainable AI
Explainable artificial intelligence (XAI) is an important advance in the field of machine learning to shed light on black box algorithms and thus a promising approach to improving artificial intelligence (AI) adoption. While previous literature has already addressed the technological benefits of XAI, there has been little research on XAI from the user’s perspective. Building upon the theory of trust, we propose a model that hypothesizes that post hoc explainability (using Shapley Additive Explanations) has a significant impact on use-related variables in this context. To test our model, we designed an experiment using a randomized controlled trial design where participants compare signatures and detect forged signatures. Surprisingly, our study shows that XAI only has a small but significant impact on perceived explainability. Nevertheless, we demonstrate that a high level of perceived explainability has a strong impact on important constructs including trust and perceived usefulness. A post hoc analysis shows that hedonic factors are significantly related to perceived explainability and require more attention in future research. We conclude with important directions for academia and for organizations.</p
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