104 research outputs found
-abelian quotients of -angulated categories
Let be a triangulated category. If is a cluster tilting
object and is the ideal of morphisms factoring
through an object of , then the quotient category
is abelian. This is an important result of cluster theory,
due to Keller-Reiten and K\"{o}nig-Zhu. More general conditions which imply
that is abelian were determined by Grimeland and the first
author.
Now let be a suitable -angulated category for an
integer . If is a cluster tilting object in the sense of
Oppermann-Thomas and is the ideal of morphisms
factoring through an object of , then we show that
is -abelian.
The notions of -angulated and -abelian categories are due to
Geiss-Keller-Oppermann and Jasso. They are higher homological generalisations
of triangulated and abelian categories, which are recovered in the special case
. We actually show that if
is the endomorphism algebra of , then is equivalent to a
-cluster tilting subcategory of in the sense of
Iyama; this implies that is -abelian. Moreover, we show
that is a -Gorenstein algebra.
More general conditions which imply that is -abelian
will also be determined, generalising the triangulated results of Grimeland and
the first author.Comment: 19 pages. This is the final accepted version, which has been accepted
for publication in the Journal of Algebr
The role of gentle algebras in higher homological algebra
We investigate the role of gentle algebras in higher homological algebra. In
the first part of the paper, we show that if the module category of a gentle
algebra contains a -cluster tilting subcategory for some , then is a radical square zero Nakayama algebra. This gives a
complete classification of weakly -representation finite gentle algebras. In
the second part, we use a geometric model of the derived category to prove a
similar result in the triangulated setup. More precisely, we show that if
contains a -cluster tilting
subcategory that is closed under , then is derived equivalent to
an algebra of Dynkin type . In this case, our approach gives a geometric
characterization of all -cluster tilting subcategories of
that are closed under .Comment: 19 pages, comments welcom
A geometric model for semilinear locally gentle algebras
We consider certain generalizations of gentle algebras that we call
semilinear locally gentle algebras. These rings are examples of semilinear
clannish algebras as introduced by the second author and Crawley-Boevey. We
generalise the notion of a nodal algebra from work of Burban and Drozd and
prove that semilinear gentle algebras are nodal by adapting a theorem of
Zembyk. We also provide a geometric realization of Zembyk's proof, which
involves cutting the surface into simpler pieces in order to endow our locally
gentle algebra with a semilinear structure. We then consider this surface glued
back together, with the seams in place, and use it to give a geometric model
for the finite-dimensional modules over the semilinear locally gentle algebra.Comment: 36 pages, comments welcom
Fatigue in low-grade glioma
Contains fulltext :
80675.pdf (publisher's version ) (Closed access)The aim of this study was to determine the prevalence and severity of fatigue in long-term survivors with a low-grade glioma (LGG), and to analyze the relationship between fatigue and demographic variables, disease duration, tumor characteristics, former tumor treatment modalities, antiepileptic drug (AED) use, self-reported concentration, motivation, and activity. Fifty-four patients with stable disease (age range, 25-73 years) who were diagnosed and treated more than 8 years ago were included in this study. Fatigue was analyzed with the Checklist Individual Strength (CIS). Thirty-nine percent of the LGG patients were severely fatigued, with older patients being most affected. Severe fatigue was associated with AED use, and with reduced self-reported concentration, motivation, and activity. No relation was found between fatigue and gender, histology, tumor laterality, disease duration, type of neurosurgical intervention and radiation treatment. Fatigue is a severe problem in a large proportion of long-term surviving LGG patients
NF-KappaB expression correlates with apoptosis and angiogenesis in clear cell renal cell carcinoma tissues
<p>Abstract</p> <p>Background</p> <p>Clear cell renal cell carcinoma (ccRCC) is the most frequently encountered tumor in the adult kidney. Many factors are known to take part in the development and progression of this tumor. Nuclear factor kappa B (NF-κB) is a family of the genes that includes five members acting in events such as inflammation and apoptosis. In this study, the role of NF-κB (p50 subunit) in ccRCC and its relation to angiogenesis and apoptosis were investigated.</p> <p>Methods</p> <p>Formalin-fixed and paraffin embedded tissue blocks from 40 patients with ccRCC were studied. Expressions of NF-κB (p50), VEGF, EGFR, bc1-2 and p53 were detected immunohistochemically. The relationship of NF-κB with these markers and clinicopathological findings were evaluated.</p> <p>Results</p> <p>The expression of NF-κB was detected in 35 (85%), VEGF in 37 (92.5%), EGFR in 38 (95%), bc1-2 in 33 (82.5%) and p53 in 13 (32.5%) of 40 ccRCC patients. Statistical analyses revealed a significant relation between NF-κB expression and VEGF (p = 0.001), EGFR (p = 0.004), bc1-2 (p = 0.010) and p53 (p = 0.037). There was no significant correlation between NF-κB and such parameters as tumor grade, stage, age and sex.</p> <p>Conclusion</p> <p>The results of this study indicated that in ccRCC cases NF-κB was associated with markers of angiogenesis and apoptosis such as VEGF, EGFR, bc1-2 and p53. In addition, the results did not only suggest a close relationship between NF-κB and VEGF, EGFR, bc1-2 and p53 in ccRCC, but also indicate that NF-κB was a potential therapeutic target in the treatment of ccRCC resistant to chemotherapy.</p
Targeting exercise interventions to patients with cancer in need:An individual patient data meta-analysis
Background:
Exercise effects in cancer patients often appear modest, possibly because interventions rarely target patients most in need. This study investigated the moderator effects of baseline values on the exercise outcomes of fatigue, aerobic fitness, muscle strength, quality of life (QoL), and self-reported physical function (PF) in cancer patients during and post-treatment.
Methods:
Individual patient data from 34 randomized exercise trials (n = 4519) were pooled. Linear mixed-effect models were used to study moderator effects of baseline values on exercise intervention outcomes and to determine whether these moderator effects differed by intervention timing (during vs post-treatment). All statistical tests were two-sided.
Results:
Moderator effects of baseline fatigue and PF were consistent across intervention timing, with greater effects in patients with worse fatigue (Pinteraction = .05) and worse PF (Pinteraction = .003). Moderator effects of baseline aerobic fitness, muscle strength, and QoL differed by intervention timing. During treatment, effects on aerobic fitness were greater for patients with better baseline aerobic fitness (Pinteraction = .002). Post-treatment, effects on upper (Pinteraction < .001) and lower (Pinteraction = .01) body muscle strength and QoL (Pinteraction < .001) were greater in patients with worse baseline values.
Conclusion:
Although exercise should be encouraged for most cancer patients during and post-treatments, targeting specific subgroups may be especially beneficial and cost effective. For fatigue and PF, interventions during and post-treatment should target patients with high fatigue and low PF. During treatment, patients experience benefit for muscle strength and QoL regardless of baseline values; however, only patients with low baseline values benefit post-treatment. For aerobic fitness, patients with low baseline values do not appear to benefit from exercise during treatment
Stretching the IR theoretical spectrum on Irish neutrality: a critical social constructivist framework
In a 2006 International Political Science Review article, entitled "Choosing to Go It Alone: Irish Neutrality in Theoretical and Comparative Perspective," Neal G. Jesse argues that Irish neutrality is best understood through a neoliberal rather than a neorealist international relations theory framework. This article posits an alternative "critical social constructivist" framework for understanding Irish neutrality. The first part of the article considers the differences between neoliberalism and social constructivism and argues why critical social constructivism's emphasis on beliefs, identity, and the agency of the public in foreign policy are key factors explaining Irish neutrality today. Using public opinion data, the second part of the article tests whether national identity, independence, ethnocentrism, attitudes to Northern Ireland, and efficacy are factors driving public support for Irish neutrality. The results show that public attitudes to Irish neutrality are structured along the dimensions of independence and identity, indicating empirical support for a critical social constructivist framework of understanding of Irish neutrality
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