15,154 research outputs found
AGN Feedback models: Correlations with star formation and observational implications of time evolution
We examine the correlation between the star formation rate (SFR) and black
hole accretion rate (BHAR) across a suite of different AGN feedback models,
using the time evolution of a merger simulation. By considering three different
stages of evolution, and a distinction between the nuclear and outer regions of
star formation, we consider 63 different cases. Despite many of the feedback
models fitting the M-\sigma\ relationship well, there are often distinct
differences in the SFR-BHAR correlations, with close to linear trends only
being present after the merger. Some of the models also show evolution in the
SFR-BHAR parameter space that is at times directly across the long-term
averaged SFR-BHAR correlation. This suggests that the observational SFR-BHAR
correlation found for ensembles of galaxies is an approximate statistical
trend, as suggested by Hickox et al. Decomposing the SFR into nuclear and outer
components also highlights notable differences between models and there is only
modest agreement with observational studies examining this in Seyfert galaxies.
For the fraction of the black hole mass growth from the merger event relative
to the final black hole mass, we find as much as a factor of three variation
among models. This also translates into a similar variation in the
post-starburst black hole mass growth. Overall, we find that while qualitative
features are often similar amongst models, precise quantitative analysis shows
there can be quite distinct differences.Comment: Accepted to MNRAS. Comments welcom
Systematic review of SGLT2 receptor inhibitors in dual or triple therapy in type 2 diabetes
Background Despite the number of medications for type 2 diabetes, many people with the condition do not achieve good glycaemic control. Some existing glucose-lowering agents have adverse effects such as weight gain or hypoglycaemia. Type 2 diabetes tends to be a progressive disease, and most patients require treatment with combinations of glucose-lowering agents. The sodium glucose co-transporter 2 (SGLT2) receptor inhibitors are a new class of glucose-lowering agents.
Objective To assess the clinical effectiveness and safety of the SGLT2 receptor inhibitors in dual or triple therapy in type 2 diabetes.
Data sources MEDLINE, Embase, Cochrane Library (all sections); Science Citation Index; trial registries; conference abstracts; drug regulatory authorities; bibliographies of retrieved papers.
Inclusion criteria Randomised controlled trials of SGLT2 receptor inhibitors compared with placebo or active comparator in type 2 diabetes in dual or combination therapy.
Methods Systematic review. Quality assessment used the Cochrane risk of bias score.
Results Seven trials, published in full, assessed dapagliflozin and one assessed canagliflozin. Trial quality appeared good. Dapagliflozin 10β
mg reduced HbA1c by β0.54% (weighted mean differences (WMD), 95% CI β0.67 to β0.40) compared to placebo, but there was no difference compared to glipizide. Canagliflozin reduced HbA1c slightly more than sitagliptin (up to β0.21% vs sitagliptin). Both dapagliflozin and canagliflozin led to weight loss (dapagliflozin WMD β1.81 kg (95% CI β2.04 to β1.57), canagliflozin up to β2.3β
kg compared to placebo).
Limitations Long-term trial extensions suggested that effects were maintained over time. Data on canagliflozin are currently available from only one paper. Costs of the drugs are not known so cost-effectiveness cannot be assessed. More data on safety are needed, with the Food and Drug Administration having concerns about breast and bladder cancers.
Conclusions Dapagliflozin appears effective in reducing HbA1c and weight in type 2 diabetes, although more safety data are needed
On the Assouad dimension of self-similar sets with overlaps
It is known that, unlike the Hausdorff dimension, the Assouad dimension of a
self-similar set can exceed the similarity dimension if there are overlaps in
the construction. Our main result is the following precise dichotomy for
self-similar sets in the line: either the \emph{weak separation property} is
satisfied, in which case the Hausdorff and Assouad dimensions coincide; or the
\emph{weak separation property} is not satisfied, in which case the Assouad
dimension is maximal (equal to one).
In the first case we prove that the self-similar set is Ahlfors regular, and
in the second case we use the fact that if the \emph{weak separation property}
is not satisfied, one can approximate the identity arbitrarily well in the
group generated by the similarity mappings, and this allows us to build a
\emph{weak tangent} that contains an interval. We also obtain results in higher
dimensions and provide illustrative examples showing that the
`equality/maximal' dichotomy does not extend to this setting.Comment: 24 pages, 2 figure
Fundamental Justice and the Deflection of Refugees from Canada
Canada is preparing to implement a controversial provision of the Immigration Act that will deny asylum seekers the opportunity even to argue their need for protection from persecution. Under a policy labelled deflection by the authors, the claims of refugees who travel to Canada through countries deemed safe, likely the United States and eventually Europe, will be rejected without any hearing on the merits. Because deflection does not require substantive or procedural harmonization of refugee law among partner states, it will severely compromise the ability of genuine refugees to seek protection. The article considers the impact of the Singh ruling of the Supreme Court of Canada and subsequent jurisprudence to determine whether a deflection system can be reconciled to the requirements of sections 7 and 1 of the Canadian Charter of Rights and Freedoms. Deflection mechanisms ought not to survive challenge under the Charter. The new procedure poses a risk to the security of the person of asylum seekers who are physically present in Canada. At the same time, it does not respect the principles of fundamental justice, and cannot be justified as necessary to deter abuse, advance national security, or promote international comity
On \u3cem\u3eΟ\u3csub\u3eΟ\u3c/sub\u3e\u3c/em\u3e-Quasinormal Subgroups of Finite Groups
Let Ο = {Οi β£ i β I} be a partition of the set of all primes P and G a finite group. A set H of subgroups of G is said to be a complete Hall Ο-set of G if every member β 1 of H is a Hall Οi-subgroup of G for some i β I and H contains exactly one Hall Οi-subgroup of G for every i such that Οi β© Ο(G) β β
.
Let ΟH(A) = {Οi β Ο(G) \ Ο(A) β£ Ο(A) β© Ο(HG) β β
for a Hall Οi-subgroup H of G}. We say that a subgroup A of G is ΟΟ-permutable or ΟΟ-quasinormal in G with respect to H if AHx = Hx A for all x β G and all H β H such that Ο(H) β ΟH(A), and ΟΟ-permutable or ΟΟ-quasinormal in G if A is ΟΟ-permutable in G with respect to some complete Hall Ο-set of G.
We study G assuming that ΟΟ-quasinormality is a transitive relation in G
Making International Refugee Law Relevant Again: A Proposal for Collectivized and Solution-Oriented Protection
International refugee law is in crisis. Even as armed conflict and human rights abuse continue to force individuals and groups to flee their home countries, many governments are withdrawing from the legal duty to provide refugees with the protection they require. While governments proclaim a willingness to assist refugees as a matter of political discretion or humanitarian goodwill, they appear committed to a pattern of defensive strategies designed to avoid international legal responsibility toward involuntary migrants. Some see this shift away from a legal paradigm of refugee protection as a source for enhanced operational flexibility in the face of changed political circumstances. For refugees themselves, however, the increasingly marginal relevance of international refugee law has in practice signalled a shift to inferior or illusory protection. It has also imposed intolerable costs on many of the poorest countries, and has involved developed states in practices antithetical to their basic political values
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