Search

Introduction Enhanced recovery after surgery (ERAS) is well established in many specialties but has not been widely adopted in renal transplantation. The aim of this survey was to understand current national practices and sentiment concerning ERAS for renal transplant recipients in the UK. Methodology A national web-based survey was sent to consultant surgeons at all 23 UK adult renal transplant units. Completed questionnaires were collected between May and July 2020. Data were analysed according to individual responses and grouped according to the existence of formal ERAS pathways within units. Results All transplant units were represented in this survey. Three units had a formal ERAS pathway for all recipients. Of the remaining units, 65.9% considered implementing an ERAS pathway in the near future. The most commonly perceived barrier to ERAS implementation was ‘embedded culture within transplant units’ (54.8% of respondents). A fifth of respondents insert surgical drains selectively and 11.7% routinely discontinue patient-controlled analgesia on postoperative day 1. Most respondents routinely remove urinary catheters on day 5 (70%) and ureteric stents 4–6 weeks post-transplantation (81.7%). Median length of stay for deceased donor kidney transplant recipients was lower in units with ERAS programmes (5–7 days versus 8–10 days, respectively). The main cited barriers for discharge were ‘suboptimal fluid balance’ and ‘requirement of treatment for rejection’. Conclusions Despite slow uptake of ERAS in kidney transplantation, appetite appears to be increasing, particularly in the post-COVID-19 era. The current practice and opinions of transplant specialists highlighted in this survey may help to establish nationally agreed ERAS guidelines in this field.

We prove that the Steinberg module of the special linear group of a quadratic imaginary number ring which is not Euclidean is not generated by integral apartments. Assuming the generalized Riemann hypothesis, this shows that the Steinberg module of a number ring is generated by integral apartments if and only if the ring is Euclidean. We also construct new cohomology classes in the top dimensional cohomology group of the special linear group of some quadratic imaginary number rings., Comment: 17 pages. To appear in Journal of Topology

Using a result of Gan–Li on F I \mathsf {FI} -hyperhomology and a semisimplicial resolution of configuration spaces due to Randal-Williams, we establish an improved representation stability stable range for configuration spaces of distinct ordered points in a manifold. Our bounds on generation degree improve the best known stability slope by a factor of 5/2 in the most general case. We adapt this result of Gan–Li to apply beyond stability arguments involving highly connected simplicial complexes, and our methods suggest that their result may be widely applicable to improving most stability ranges for F I \mathsf {FI} -modules in the current representation stability literature.

Background Biliary leaks and anastomotic strictures are common early anastomotic biliary complications (EABCs) following liver transplantation. However, there are no large multicentre studies investigating their clinical impact or risk factors. This study aimed to define the incidence, risk factors and impact of EABC. Methods The NHS registry on adult liver transplantation between 2006 and 2017 was reviewed retrospectively. Adjusted regression models were used to assess predictors of EABC, and their impact on outcomes. Results Analyses included 8304 liver transplant recipients. Patients with EABC (9·6 per cent) had prolonged hospitalization (23 versus 15 days; P, Early anastomotic biliary complications are common following liver transplantation. In this national registry analysis we show that these complications have a significant, independent, impact on graft loss and mortality following transplantation. We also identify a number of key risk factors for development of early anastomotic biliary complications.

The quantity of health spending does not equate directly to the quality of healthcare. Social spending and nonmedical determinants of health impact on health outcomes. The value of health spending in the United States is limited by the high cost of goods and labor, and administrative costs, high use of low-level care, and lack of basic healthcare coverage in a substantial minority of the population. There are additional reasons for differences in the value of health spending as revealed by a comparison of Canada and Australia, where similar spending per capita results in better health system performance in Australia than in Canada. Within Canada, there are large differences between provinces in the value of health spending. Overutilization of health resources occurs when an intervention is not indicated, or of low value, or is provided at the wrong time. The Choosing Wisely Initiative is a solution for overutilization of low-value care. Recognition of the reality that effective treatments are often applied inconsistently and inappropriately has spurred the development of a science concerned with improvement of quality of care.

Background Asthma is a highly prevalent chronic disease among Ontario children; however, the extent to which rural status and distance are associated with unplanned emergency department (ED) use by this population is largely unknown. Objective To explore the impact of rurality and geographical distance to primary and specialist care services on healthcare utilization by analyzing the use of unplanned ED services. Methods A population level retrospective cohort study of Ontario children ages 5–14 with newly diagnosed asthma was conducted using health administrative data from Institute for Clinical Evaluative Sciences (ICES). Adjusted logistic regression models were used to analyze the association between unplanned ED use with rural status and distance to general practitioner/family physician (GP/FP) and specialist healthcare services, while controlling for confounders. Results In total, 19,732 individuals met the inclusion criteria. Individuals who lived in rural locations (OR 2.00, 95% CI 1.64–2.44) and travelled >50 km to a GP/FP (OR 1.25, 95% CI 1.06–1.48) or specialist (OR 1.20, 95% CI 1.05–1.38) were more likely to utilize an ED. Conclusion Children with asthma utilize healthcare services differently based on rural status and distance to services. To ensure equitable access to care, there is a need to accommodate for these factors in the planning and provision of asthma healthcare services.

Previous Mendelian randomization (MR) studies on 25-hydroxyvitamin D (25(OH)D) and cancer have typically adopted a handful of variants and found no relationship between 25(OH)D and cancer; however, issues of horizontal pleiotropy cannot be reliably addressed. Using a larger set of variants associated with 25(OH)D (74 SNPs, up from 6 previously), we perform a unified MR analysis to re-evaluate the relationship between 25(OH)D and ten cancers. Our findings are broadly consistent with previous MR studies indicating no relationship, apart from ovarian cancers (OR 0.89; 95% C.I: 0.82 to 0.96 per 1 SD change in 25(OH)D concentration) and basal cell carcinoma (OR 1.16; 95% C.I.: 1.04 to 1.28). However, after adjustment for pigmentation related variables in a multivariable MR framework, the BCC findings were attenuated. Here we report that lower 25(OH)D is unlikely to be a causal risk factor for most cancers, with our study providing more precise confidence intervals than previously possible., Studies of the genetic association between vitamin D and cancer risk have typically been underpowered. Here the authors analyse this using Mendelian Randomisation with more than 70 vitamin D variants obtained from the UK Biobank and large-scale data from various consortia, confirming null associations between vitamin D and most cancers.

We study presentations of the virtual dualizing modules of special linear groups of number rings, the Steinberg modules. Bykovskii gave a presentation for the Steinberg modules of the integers, and our main result is a generalization of this presentation to the Gaussian integers and the Eisenstein integers. We also show that this generalization does not give a presentation for the Steinberg modules of several Euclidean number rings., Comment: Minor revisions based on referee's comments. Accepted for publication at IMRN

In this paper we study the characters of sequences of representations of any of the three families of classical Weyl groups $$\mathcal {W}_n$$ : the symmetric groups, the signed permutation groups (hyperoctahedral groups), or the even-signed permutation groups. Our results extend work of Church et al. (Duke Math J, 2012. arXiv:1204.4533 ; Geom Topol 18(5):2951–2984, 2014) on the symmetric groups. We use the concept of an $$\text {FI}_{\mathcal {W}}$$ -module, an algebraic object that encodes the data of a sequence of $$\mathcal {W}_n$$ -representations with maps between them, defined in the author’s recent work (J Algebra 420:269–332, 2014). We show that if a sequence $$\{V_n\}$$ of $$\mathcal {W}_n$$ -representations has the structure of a finitely generated $$\text {FI}_{\mathcal {W}}$$ -module, then there are substantial constraints on the growth of the sequence and the structure of the characters: for $$n$$ large, the dimension of $$V_n$$ is equal to a polynomial in $$n$$ , and the characters of $$V_n$$ are given by a character polynomial in signed-cycle-counting class functions, independent of $$n$$ . We determine bounds the degrees of these polynomials. We continue to develop the theory of $$\text {FI}_{\mathcal {W}}$$ -modules, and we apply this theory to obtain new results about a number of sequences associated to the classical Weyl groups: the cohomology of complements of classical Coxeter hyperplane arrangements, and the cohomology of the pure string motion groups (the groups of symmetric automorphisms of the free group).

In this paper we develop machinery for studying sequences of representations of any of the three families of classical Weyl groups, extending work of Church, Ellenberg, Farb, and Nagpal [7,8] on the symmetric groups S n to the signed permutation groups B n and the even-signed permutation groups D n . For each family W n , we present an algebraic framework where a sequence V n of W n -representations is encoded into a single object we call an FI W -module . We prove that if an FI W -module V satisfies a simple finite generation condition then the structure of the sequence is highly constrained. One consequence is that the sequence is uniformly representation stable in the sense of Church–Farb, that is, the pattern of irreducible representations in the decomposition of each V n eventually stabilizes in a precise sense. Using the theory developed here we obtain new results about the cohomology of generalized flag varieties associated to the classical Weyl groups, and more generally the r -diagonal coinvariant algebras. We analyze the algebraic structure of the category of FI W -modules, and introduce restriction and induction operations that enable us to study interactions between the three families of groups. We use this theory to prove analogues of Murnaghan's 1938 stability theorem for Kronecker coefficients for the families B n and D n . The theory of FI W -modules gives a conceptual framework for stability results such as these.

We introduce a technique for proving quantitative representation stability theorems for sequences of representations of certain finite linear groups over a field of characteristic zero. In particular, we prove a vanishing result for higher syzygies of VIC- and SI-modules, which can be thought of as a weaker version of a regularity theorem of Church-Ellenberg in the context of FI-modules. We apply these techniques to the rational homology of congruence subgroups of mapping class groups and congruence subgroups of automorphism groups of free groups. This partially resolves a question raised by Church and Putman-Sam. We also prove new homological stability results for mapping class groups and automorphism groups of free groups with twisted coefficients., Comment: We have revised Section 4 to correct an error in the previous version. 35 pages, 6 figures. To appear in IMRN

In this paper we explore a relationship between the topology of the complex hyperplane complements $\mathcal{M}_{BC_n} (\mathbb{C})$ in type B/C and the combinatorics of certain spaces of degree-$n$ polynomials over a finite field $\mathbb{F}_q$. This relationship is a consequence of the Grothendieck trace formula and work of Lehrer and Kim. We use it to prove a correspondence between a representation-theoretic convergence result on the cohomology algebras $H^*(\mathcal{M}_{BC_n} (\mathbb{C});\mathbb{C})$, and an asymptotic stability result for certain polynomial statistics on monic squarefree polynomials over $\mathbb{F}_q$ with nonzero constant term. This result is the type B/C analogue of a theorem due to Church, Ellenberg, and Farb in type A, and we include a new proof of their theorem. To establish these convergence results, we realize the sequences of cohomology algebras of the hyperplane complements as FI$_\mathcal{W}$-algebras finitely generated in FI$_\mathcal{W}$- degree $2$, and we investigate the asymptotic behaviour of general families of algebras with this structure. We prove a negative result implying that this structure alone is not sufficient to prove the necessary convergence conditions. Our proof of convergence for the cohomology algebras involves the combinatorics of their relators., Comment: 36 pages. The new version added a citation. Comments welcome!

Using the language of twisted skew-commutative algebras, we define \emph{secondary representation stability}, a stability pattern in the {\it unstable} homology of spaces that are representation stable in the sense of Church, Ellenberg, and Farb. We show that the rational homology of configuration spaces of ordered points in noncompact manifolds satisfies secondary representation stability. While representation stability for the homology of configuration spaces involves stabilizing by introducing a point ``near infinity,'' secondary representation stability involves stabilizing by introducing a pair of orbiting points -- an operation that relates homology groups in different homological degrees. This result can be thought of as a representation-theoretic analogue of \emph{secondary homological stability} in the sense of Galatius, Kupers, and Randal-Williams. In the course of the proof we establish some additional results: we give a new characterization of the homology of the complex of injective words, and we give a new proof of integral representation stability for configuration spaces of noncompact manifolds, extending previous results to nonorientable manifolds., 45 pages, 41 figures. Minor corrections and revisions made throughout to clarify and shorten the paper. For reasons for length the appendix has been cut and will be made into a separate paper. Final version; accepted at Geometry & Topology