5,120 research outputs found
Improved bounds for Hadwiger's covering problem via thin-shell estimates
A central problem in discrete geometry, known as Hadwiger's covering problem,
asks what the smallest natural number is such that every
convex body in can be covered by a union of the interiors of
at most of its translates. Despite continuous efforts, the
best general upper bound known for this number remains as it was more than
sixty years ago, of the order of .
In this note, we improve this bound by a sub-exponential factor. That is, we
prove a bound of the order of for some universal
constant .
Our approach combines ideas from previous work by Artstein-Avidan and the
second named author with tools from Asymptotic Geometric Analysis. One of the
key steps is proving a new lower bound for the maximum volume of the
intersection of a convex body with a translate of ; in fact, we get the
same lower bound for the volume of the intersection of and when they
both have barycenter at the origin. To do so, we make use of measure
concentration, and in particular of thin-shell estimates for isotropic
log-concave measures.
Using the same ideas, we establish an exponentially better bound for
when restricting our attention to convex bodies that are
. By a slightly different approach, an exponential improvement is
established also for classes of convex bodies with positive modulus of
convexity
Recognizing Image Style
The style of an image plays a significant role in how it is viewed, but style
has received little attention in computer vision research. We describe an
approach to predicting style of images, and perform a thorough evaluation of
different image features for these tasks. We find that features learned in a
multi-layer network generally perform best -- even when trained with object
class (not style) labels. Our large-scale learning methods results in the best
published performance on an existing dataset of aesthetic ratings and
photographic style annotations. We present two novel datasets: 80K Flickr
photographs annotated with 20 curated style labels, and 85K paintings annotated
with 25 style/genre labels. Our approach shows excellent classification
performance on both datasets. We use the learned classifiers to extend
traditional tag-based image search to consider stylistic constraints, and
demonstrate cross-dataset understanding of style
Privacy-Preserving Electronic Ticket Scheme with Attribute-based Credentials
Electronic tickets (e-tickets) are electronic versions of paper tickets,
which enable users to access intended services and improve services'
efficiency. However, privacy may be a concern of e-ticket users. In this paper,
a privacy-preserving electronic ticket scheme with attribute-based credentials
is proposed to protect users' privacy and facilitate ticketing based on a
user's attributes. Our proposed scheme makes the following contributions: (1)
users can buy different tickets from ticket sellers without releasing their
exact attributes; (2) two tickets of the same user cannot be linked; (3) a
ticket cannot be transferred to another user; (4) a ticket cannot be double
spent; (5) the security of the proposed scheme is formally proven and reduced
to well known (q-strong Diffie-Hellman) complexity assumption; (6) the scheme
has been implemented and its performance empirically evaluated. To the best of
our knowledge, our privacy-preserving attribute-based e-ticket scheme is the
first one providing these five features. Application areas of our scheme
include event or transport tickets where users must convince ticket sellers
that their attributes (e.g. age, profession, location) satisfy the ticket price
policies to buy discounted tickets. More generally, our scheme can be used in
any system where access to services is only dependent on a user's attributes
(or entitlements) but not their identities.Comment: 18pages, 6 figures, 2 table
CD81 and claudin 1 coreceptor association: role in hepatitis C virus entry.
Hepatitis C virus (HCV) is an enveloped positive-stranded RNA hepatotropic virus. HCV pseudoparticles infect liver-derived cells, supporting a model in which liver-specific molecules define HCV internalization. Three host cell molecules have been reported to be important entry factors or receptors for HCV internalization: scavenger receptor BI, the tetraspanin CD81, and the tight junction protein claudin-1 (CLDN1). None of the receptors are uniquely expressed within the liver, leading us to hypothesize that their organization within hepatocytes may explain receptor activity. Since CD81 and CLDN1 act as coreceptors during late stages in the entry process, we investigated their association in a variety of cell lines and human liver tissue. Imaging techniques that take advantage of fluorescence resonance energy transfer (FRET) to study protein-protein interactions have been developed. Aequorea coerulescens green fluorescent protein- and Discosoma sp. red-monomer fluorescent protein-tagged forms of CD81 and CLDN1 colocalized, and FRET occurred between the tagged coreceptors at comparable frequencies in permissive and nonpermissive cells, consistent with the formation of coreceptor complexes. FRET occurred between antibodies specific for CD81 and CLDN1 bound to human liver tissue, suggesting the presence of coreceptor complexes in liver tissue. HCV infection and treatment of Huh-7.5 cells with recombinant HCV E1-E2 glycoproteins and anti-CD81 monoclonal antibody modulated homotypic (CD81-CD81) and heterotypic (CD81-CLDN1) coreceptor protein association(s) at specific cellular locations, suggesting distinct roles in the viral entry process
Intensive glycemic treatment during Type 1 diabetes pregnancy: A story of (mostly) sweet success!
Studies from Scotland and Canada confirm large increases in the incidence of pregnancies complicated by pregestational type 1 diabetes (T1D). With this increased antenatal workload comes more specialization and staff expertise, which may be important as diabetes technology use increases. While euglycemia remains elusive and obstetrical intervention (earlier delivery, increased operative deliveries) is increasing, there have been some notable successes in the past 5–10 years. These include a decline in the rates of congenital anomaly (Canada) and stillbirths (U.K.) and substantial reductions in both maternal hypoglycemia (both moderate and severe) across many countries. However, pregnant women with T1D still spend ∼30–45% of the time (8–11 h/day) hyperglycemic during the second and third trimesters. The duration of maternal hyperglycemia appears unchanged in routine clinical care over the past decade. This ongoing fetal exposure to maternal hyperglycemia likely explains the persistent rates of large for gestational age (LGA), neonatal hypoglycemia, and neonatal intensive care unit (NICU) admissions in T1D offspring. The Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) found that pregnant women using real-time continuous glucose monitoring (CGM) spent 5% less time (1.2 h/day) hyperglycemic during the third trimester, with clinically relevant reductions in LGA, neonatal hypoglycemia, and NICU admissions. This article will review the progress in our understanding of the intensive glycemic treatment of T1D pregnancy, focusing in particular on the recent technological advances in CGM and automated insulin delivery. It suggests that even with advanced diabetes technology, optimal maternal dietary intake is needed to minimize the neonatal complications attributed to postprandial hyperglycemia
Immunity to self co-generates regulatory T cells
Immune responses to self are kept in check by tolerance mechanisms, including suppression by regulatory T cells (Tregs). The defective generation of Tregs specific for self-antigens may lead to autoimmune disease. We identified a novel population of human CD4^+^ Tregs, characterized by high surface expression of CD52, which is co-generated in response to autoantigen. Blood CD4^+^CD52^hi^ T cells were generated preferentially in response to low-dose autoantigen and suppressed proliferation and interferon-[gamma] production by other T cells. Depletion of resting CD4^+^CD52^hi^ T cells enhanced the T-cell response to autoantigen. CD4^+^CD52^hi^ Tregs were neither derived from nor distinguished by markers of conventional resting CD4^+^CD25^+^ Tregs. In response to the pancreatic islet autoantigens glutamic acid decarboxylase, the generation of CD4^+^CD52^hi^ Tregs was impaired in individuals with and at-risk for type 1 diabetes, compared to healthy controls and individuals with type 2 diabetes. CD4^+^CD52^hi^ Tregs co-generated to self-antigen may therefore contribute to immune homeostasis and protect against autoimmune disease
Comparative evaluation of [(99m)tc]tilmanocept for sentinel lymph node mapping in breast cancer patients: results of two phase 3 trials.
BackgroundSentinel lymph node (SLN) surgery is used worldwide for staging breast cancer patients and helps limit axillary lymph node dissection. [(99m)Tc]Tilmanocept is a novel receptor-targeted radiopharmaceutical evaluated in 2 open-label, nonrandomized, within-patient, phase 3 trials designed to assess the lymphatic mapping performance.MethodsA total of 13 centers contributed 148 patients with breast cancer. Each patient received [(99m)Tc]tilmanocept and vital blue dye (VBD). Lymph nodes identified intraoperatively as radioactive and/or blue stained were excised and histologically examined. The primary endpoint, concordance (lower boundary set point at 90 %), was the proportion of nodes detected by VBD and [(99m)Tc]tilmanocept.ResultsA total of 13 centers contributed 148 patients who were injected with both agents. Intraoperatively, 207 of 209 nodes detected by VBD were also detected by [(99m)Tc]tilmanocept for a concordance rate of 99.04 % (p < 0.0001). [(99m)Tc]tilmanocept detected a total of 320 nodes, of which 207 (64.7 %) were detected by VBD. [(99m)Tc]Tilmanocept detected at least 1 SLN in more patients (146) than did VBD (131, p < 0.0001). In 129 of 131 patients with ≥1 blue node, all blue nodes were radioactive. Of 33 pathology-positive nodes (18.2 % patient pathology rate), [(99m)Tc]tilmanocept detected 31 of 33, whereas VBD detected only 25 of 33 (p = 0.0312). No pathology-positive SLNs were detected exclusively by VBD. No serious adverse events were attributed to [(99m)Tc]tilmanocept.Conclusion[(99m)Tc]Tilmanocept demonstrated success in detecting a SLN while meeting the primary endpoint. Interestingly, [(99m)Tc]tilmanocept was additionally noted to identify more SLNs in more patients. This localization represented a higher number of metastatic breast cancer lymph nodes than that of VBD
Photocatalytic degradation of contaminants of concern with composite NF-TiO2 films under visible and solar light
This study reports the synthesis and characterization of composite nitrogen and fluorine co-doped titanium dioxide (NF-TiO2) for the removal of contaminants of concern (COCs) in wastewater under visible and solar light. Monodisperse anatase TiO2 nanoparticles of different sizes and Evonik P25 were assembled to immobilized NF-TiO2 by direct incorporation into the sol-gel or by the layer-by-layer technique. The composite films were characterized with X-ray diffraction, high resolution-transmission electron microscopy, environmental scanning electron microscopy, and porosimetry analysis. The photocatalytic degradation of atrazine, carbamazepine, and caffeine was evaluated in a synthetic water solution and in an effluent from a hybrid biological concentrator reactor (BCR). Minor aggregation and improved distribution of monodisperse titania particles was obtained with NF-TiO2-monodisperse (10 and 50 nm) from the layer-by-layer technique than with NF-TiO2 + monodisperse TiO2 (300 nm) directly incorporated into the sol. The photocatalysts synthesized with the layer-by-layer method achieved significantly higher degradation rates in contrast with NF-TiO2-monodisperse titania (300 nm) and slightly faster values when compared with NF-TiO2-P25. Using NF-TiO2 layer-by-layer with monodisperse TiO2 (50 nm) under the solar light irradiation, the respective degradation rates in synthetic water and BCR effluent were 14.6 and 9.5·10-3 min-1 for caffeine, 12.5 and 9.0·10-3 min-1 for carbamazepine, and 10.9 and 5.8·10-3 min-1 for atrazine. These results suggest that the layer-by-layer technique is a promising method for the synthesis of composite TiO2-based films compared to the direct addition of nanoparticles into the sol
A Comprehensive Single Institutional Review of 2 Years in a Designated Fast-Track Sarcoma Diagnostic Clinic Linked with a Sarcoma Specialist Advisory Group: Meeting the Target but Failing the Task?
Background. National guidelines prompted the implementation of a designated two-week wait referral pathway to facilitate the early diagnosis of sarcomas, to improve treatment outcomes. Methods. Patients referred to the Cambridge Sarcoma Diagnostic Clinic between January 2013 and December 2014 were identified through the electronic appointments system. Information was retrospectively retrieved about patient characteristics and details of the diagnostic pathway. Results. 17.3% of patients referred (69/397) were diagnosed with a malignancy. Of these, 59.3% (41/69) had primary sarcomas, 17.4% (12/69) had metastatic cancer, and 23.2% (16/69) had a different primary malignancy. 15% of the 41 sarcomas were 10 cm. Sarcomas diagnosed through this clinic represented 13% (41/315) of sarcomas managed at the centre during the same 2 years. Conclusion. While we achieved the target of 10% (41/397) sarcoma diagnosis rate in the rapid access clinic, only 15% of these were <5 cm better prognosis lesions. This calls into question the "real world" impact of such diagnostic clinics on early diagnosis of sarcomas. In order to enhance generic cancer diagnostic skills, training in these diagnostic clinics could be usefully integrated into national training curricula for both surgical and nonsurgical oncologists.This is the final version of the article. It first appeared from the Hindawi Publishing Corporation via http://dx.doi.org/10.1155/2016/603260
Cicada Grove
The gentle throb of cicada song is an essential element of hot summer nights. The annual performance not only reminds people of a carefree childhood, but also signals a rich ecosystem. The cycle of cicada emergence is emblematic of the natural cycles of growth and decay.
This project proposes a neighborhood hub—an epicenter of cicada habitat and social activities. Located in the heart of the historical West End neighborhood and sited between apartment complexes, parking lots, and a playground, Cicada Grove is both a productive garden, a gathering space, and a place of repose where the song of the cicada transcends all.https://openscholarship.wustl.edu/spring2019_margetts/1002/thumbnail.jp
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