scholarly journals STABLE LEFT AND RIGHT BOUSFIELD LOCALISATIONS

2013 ◽  
Vol 56 (1) ◽  
pp. 13-42 ◽  
Author(s):  
DAVID BARNES ◽  
CONSTANZE ROITZHEIM
Keyword(s):  
Homology Theory ◽  
Homotopy Category ◽  
Stable Model ◽  
Model Categories ◽  
Morita Theory ◽  
Left And Right ◽  
Torsion Modules ◽  
Model Structures ◽  
Insight Into ◽  
Complete Characterisation

AbstractWe study left and right Bousfield localisations of stable model categories which preserve stability. This follows the lead of the two key examples: localisations of spectra with respect to a homology theory and A-torsion modules over a ring R with A a perfect R-algebra. We exploit stability to see that the resulting model structures are technically far better behaved than the general case. We can give explicit sets of generating cofibrations, show that these localisations preserve properness and give a complete characterisation of when they preserve monoidal structures. We apply these results to obtain convenient assumptions under which a stable model category is spectral. We then use Morita theory to gain an insight into the nature of right localisation and its homotopy category. We finish with a correspondence between left and right localisation.

Model Structures for the 𝔸1-homotopy Category

2019 ◽  
pp. 175-212
Author(s):  
Christian Haesemeyer ◽  
Charles A. Weibel
Keyword(s):  
Full Subcategory ◽  
Homotopy Category ◽  
Symmetric Power ◽  
Model Structure ◽  
Model Categories ◽  
Simplicial Presheaves ◽  
Basic Ideas ◽  
Quillen Model ◽  
Model Structures ◽  
Bousfield Localization

This chapter provides the 𝔸1-local projective model structure on the categories of simplicial presheaves and simplicial presheaves with transfers. These model categories, written as Δ‎opPshv(Sm)𝔸1 and Δ‎op PST(Sm)𝔸1, are first defined. Their respective homotopy categories are Ho(Sm) and the full subcategory DM eff nis ≤0 of DM eff nis. Afterward, this chapter introduces the notions of radditive presheaves and ̅Δ‎-closed classes, and develops their basic properties. The theory of ̅Δ‎-closed classes is needed because the extension of symmetric power functors to simplicial radditive presheaves is not a left adjoint. This chapter uses many of the basic ideas of Quillen model categories, which is a category equipped with three classes of morphisms satisfying five axioms. In addition, much of the material in this chapter is based upon the technique of Bousfield localization.

scholarly journals Path homology theory of edge-colored graphs

2021 ◽  
Vol 19 (1) ◽  
pp. 706-723
Author(s):  
Yuri V. Muranov ◽  
Anna Szczepkowska
Keyword(s):  
Spectral Sequence ◽  
Edge Coloring ◽  
Homology Theory ◽  
Homotopy Category ◽  
Homology Groups ◽  
Colored Graphs ◽  
Natural Filtration ◽  
Definition Of ◽  
Exact Sequences

Abstract In this paper, we introduce the category and the homotopy category of edge-colored digraphs and construct the functorial homology theory on the foundation of the path homology theory provided by Grigoryan, Muranov, and Shing-Tung Yau. We give the construction of the path homology theory for edge-colored graphs that follows immediately from the consideration of natural functor from the category of graphs to the subcategory of symmetrical digraphs. We describe the natural filtration of path homology groups of any digraph equipped with edge coloring, provide the definition of the corresponding spectral sequence, and obtain commutative diagrams and braids of exact sequences.

Abstract 18021: Functional Substrates as the Strongest Predictor of Outcomes in Patients Presenting for Ventricular Arrhythmia Ablation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Justin Hayase ◽  
Yonatan Faiwiszewski ◽  
Stephen Vampola ◽  
Aron Bender ◽  
Gordon Ho ◽  
...  
Keyword(s):  
Ventricular Arrhythmia ◽  
Patient Outcomes ◽  
Roc Analysis ◽  
Youden Index ◽  
History Of ◽  
Forward Stepwise ◽  
Left And Right ◽  
Insight Into ◽  
Procedural Outcome

Introduction: Recent work has shown that rotor characteristics can distinguish sustained versus non-sustained ventricular fibrillation (VF). However, the significance of functional VF substrates on patient outcomes is not studied. Methods: In 26 consecutive patients presenting for ventricular arrhythmia ablation procedures, 64-electrode basket catheters were inserted into both the left and right ventricles and VF was induced and defibrillated at 11±3 seconds. Computational phase analysis was performed and each VF cycle was characterized as rotor, focal, or disorganized activation. Follow-up data were analyzed for arrhythmia recurrence and compared to rotor stability. Forward stepwise regression analysis incorporating age, history of CHF, history of a-fib, history of prior MI, number of VTs induced, and presence of post-procedure inducible VT was performed to determine the strongest predictor of procedural outcome. Results: Of 26 patients, 19 had sustained VF, and 16 underwent attempted ablation (7 VT, 9 PVC). Optimization of the Youden index for the ROC analysis regarding rotor stability and procedural outcome demonstrated that maximum rotor stability of > 14.5 rotations (corresponding to total rotor prevalence of 71%) provided optimal sensitivity of 85% and specificity of 87% for arrhythmia recurrence. Among these, greater rotor stability was significantly associated with ventricular arrhythmia recurrence (86% versus 11%, p = 0.01) (Table 1), and was the strongest predictor of outcomes. Recurrence was independent of presenting arrhythmia. Conclusions: Functional VF/VT metrics were the strongest predictor of ventricular arrhythmia outcomes compared to traditional predictors in this series of patients. This suggests that functional substrate characteristics may provide added insight into recurrence mechanisms. Whether they may identify a target for future interventions requires further study.

scholarly journals Stable model categories are categories of modules

Topology ◽  
2003 ◽  
Vol 42 (1) ◽  
pp. 103-153 ◽  
Author(s):  
Stefan Schwede ◽  
Brooke Shipley
Keyword(s):  
Stable Model ◽  
Model Categories

FLUCTUATIONS AND INTERACTIONS BETWEEN BRAIN WAVES DURING DEEP AND SHALLOW ANESTHESIA

2012 ◽  
Vol 11 (01) ◽  
pp. 1240018 ◽  
Author(s):  
B. MUSIZZA ◽  
F. F. BAJROVIĆ ◽  
J. PETROVČIČ ◽  
A. STEFANOVSKA ◽  
S. RIBARIČ
Keyword(s):  
Slow Wave ◽  
Wavelet Transforms ◽  
Spectral Power ◽  
Low Frequency ◽  
Autism Spectrum ◽  
Brain Dynamics ◽  
Brain Waves ◽  
Coupling Strengths ◽  
Left And Right ◽  
Insight Into

Using gold plated electrodes, inserted into the rat's head above the dura of the left and right parietal cortex, we recorded EEG during deep and shallow anesthesia with either pentobarbital (PB) or ketamine-xylazine (KX). The fluctuations in time series were then analyzed using wavelet transforms and the spectral power was determined within 7 frequency intervals (slow wave 2, S2, 0.0067–0.0167 Hz; slow wave 1, S1, 0.02–0.19 Hz; δ, 0.2–3.9 Hz; θ, 4–7.9 Hz; α, 8–12.9 Hz; β, 13–24.9 Hz and γ, 25–34.9 Hz). In addition, the coupling strengths between individual oscillatory components during deep and shallow anesthesia were evaluated for both anesthetics. We show specific changes for both anesthetics indicating that during deep anesthesia PB reduces high and low frequency activity (0.2–35 Hz) and enhances coupling especially between δ, θ and α waves, while KX reduces low frequency activity (0.005 to 0.2 Hz) and enhances coupling between frequency waves α, β and γ. Our results, using two anesthetics known to block different ion channels, provide an insight into brain dynamics and could have wide implications in creating biomarkers for detecting various neurophysiological modifications, such as in Alzheimer and Parkinson's disease or Autism spectrum disorder, as well as in providing more realistic models of brain dynamics.

scholarly journals The Vibrio Pathogenicity Island of Epidemic Vibrio cholerae Forms Precise Extrachromosomal Circular Excision Products

2003 ◽  
Vol 185 (23) ◽  
pp. 6893-6901 ◽  
Author(s):  
C. Rajanna ◽  
J. Wang ◽  
D. Zhang ◽  
Zheng Xu ◽  
A. Ali ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Virulence Gene ◽  
Pathogenicity Island ◽  
Pcr Analysis ◽  
Integrase Gene ◽  
Site Specific ◽  
The Core ◽  
Left And Right ◽  
The Right ◽  
Insight Into

ABSTRACT The Vibrio pathogenicity island (VPI) in epidemic Vibrio cholerae is an essential virulence gene cluster. Like many pathogenicity islands, the VPI has at its termini a phage-like integrase gene (int), a transposase-like gene (vpiT), and phage-like attachment (att) sites, and is inserted at a tRNA-like locus (ssrA). We report that the VPI precisely excises from the chromosome and that its left and right ends join to form an extrachromosomal circular excision product (pVPI). Two-stage nested PCR analysis and DNA sequencing confirmed the int-att-vpiT junction and that the core attP of pVPI is identical to the chromosomal VPI attR site. Excision was independent of toxR and toxT. Excision was independent of recA, suggesting that it is mediated by site-specific recombination. Interestingly, while excision was detected in int and vpiT mutants, excision was abolished in a double (int vpiT) mutant and was restored by plasmids containing genes for either recombinase. Excision results in deletion of A361 in the ssrA locus, which flanks the right junction of the VPI. Since A361 encodes U70 in the critical G · U base pair in the acceptor stem of the ssrA RNA that is the determinant for aminoacylation with alanine, this deletion might have deleterious effects on ssrA function. Also, vpiT may have undergone interchromosomal translocation or may represent an independent integration event, as it was found downstream of hutA in some isolates. Our results provide new insight into the molecular biology of the VPI, and we propose that the process of excision and circularization is important in the emergence, pathogenesis, and persistence of epidemic V. cholerae.

scholarly journals Cuttlefish dynamic camouflage: responses to substrate choice and integration of multiple visual cues

2009 ◽  
Vol 277 (1684) ◽  
pp. 1031-1039 ◽  
Author(s):  
Justine J. Allen ◽  
Lydia M. Mäthger ◽  
Alexandra Barbosa ◽  
Kendra C. Buresch ◽  
Emilia Sogin ◽  
...  
Keyword(s):  
Visual Cues ◽  
Substrate Preference ◽  
Artificial Substrates ◽  
Energy Costs ◽  
Evolutionary Response ◽  
Substrate Choice ◽  
Left And Right ◽  
Body Patterns ◽  
Insight Into ◽  
Body Pattern

Prey camouflage is an evolutionary response to predation pressure. Cephalopods have extensive camouflage capabilities and studying them can offer insight into effective camouflage design. Here, we examine whether cuttlefish, Sepia officinalis , show substrate or camouflage pattern preferences. In the first two experiments, cuttlefish were presented with a choice between different artificial substrates or between different natural substrates. First, the ability of cuttlefish to show substrate preference on artificial and natural substrates was established. Next, cuttlefish were offered substrates known to evoke three main camouflage body pattern types these animals show: Uniform or Mottle (function by background matching); or Disruptive. In a third experiment, cuttlefish were presented with conflicting visual cues on their left and right sides to assess their camouflage response. Given a choice between substrates they might encounter in nature, we found no strong substrate preference except when cuttlefish could bury themselves. Additionally, cuttlefish responded to conflicting visual cues with mixed body patterns in both the substrate preference and split substrate experiments. These results suggest that differences in energy costs for different camouflage body patterns may be minor and that pattern mixing and symmetry may play important roles in camouflage.

scholarly journals Aberrant Cerebello-Cerebral Connectivity in Remitted Bipolar Patients 1 and 2: New Insight into Understanding the Cerebellar Role in Mania and Hypomania

2021 ◽  
Author(s):  
Giusy Olivito ◽  
Michela Lupo ◽  
Andrea Gragnani ◽  
Marco Saettoni ◽  
Libera Siciliano ◽  
...  
Keyword(s):  
Dentate Nucleus ◽  
Compensatory Mechanism ◽  
Resting State Functional Connectivity ◽  
Neural Correlate ◽  
Functional Studies ◽  
Left And Right ◽  
Bipolar Patients ◽  
The Brain ◽  
Insight Into

AbstractBipolar disorder (BD) is a major mental illness characterized by periods of (hypo) mania and depression with inter-episode remission periods. Functional studies in BD have consistently implicated a set of linked cortical and subcortical limbic regions in the pathophysiology of the disorder, also including the cerebellum. However, the cerebellar role in the neurobiology of BD still needs to be clarified. Seventeen euthymic patients with BD type1 (BD1) (mean age/SD, 38.64/13.48; M/F, 9/8) and 13 euthymic patients with BD type 2 (BD2) (mean age/SD, 41.42/14.38; M/F, 6/7) were compared with 37 sex- and age-matched healthy subjects (HS) (mean age/SD, 45.65/14.15; M/F, 15/22). T1 weighted and resting-state functional connectivity (FC) scans were acquired. The left and right dentate nucleus were used as seed regions for the seed based analysis. FC between each seed and the rest of the brain was compared between patients and HS. Correlations between altered cerebello-cerebral connectivity and clinical scores were then investigated. Different patterns of altered dentate-cerebral connectivity were found in BD1 and BD2. Overall, impaired dentate-cerebral connectivity involved regions of the anterior limbic network specifically related to the (hypo)manic states of BD. Cerebello-cerebral connectivity is altered in BD1 and BD2. Interestingly, the fact that these altered FC patterns persist during euthymia, supports the hypothesis that cerebello-cerebral FC changes reflect the neural correlate of subthreshold symptoms, as trait-based pathophysiology and/or compensatory mechanism to maintain a state of euthymia.

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