Pseudo-Automorphisms of positive entropy on the blowups of products of projective spaces

We use a concise method to construct pseudo-automorphisms f_n of the first dynamical degree d_1(f_n) > 1 on the blowups of the projective n-space for all n > 1 and more generally on the blowups of products of projective spaces. These f_n, for n = 3 have positive entropy, and for n > 3 seem to be the first examples of pseudo-automorphisms with d_1(f_n) > 1 (and of non-product type) on rational varieties of higher dimensions.Comment: Mathematische Annalen (to appear

Inpatient urine cultures are frequently performed without urinalysis or microscopy: Findings from a large academic medical center

OBJECTIVETo describe the frequency of urine cultures performed in inpatients without additional testing for pyuriaDESIGNRetrospective cohort studySETTINGA 1,250-bed academic tertiary referral centerPATIENTSHospitalized adultsMETHODSThis study included urine cultures drawn on 4 medical and 2 surgical wards from 2009 to 2013 and in the medical and surgical intensive care units (ICUs) from 2012 to 2013. Patient and laboratory data were abstracted from the hospital’s medical informatics database. We identified catheter-associated urinary tract infections (CAUTIs) in the ICUs by routine infection prevention surveillance. Cultures without urinalysis or urine microscopy were defined as “isolated.” The primary outcome was the proportion of isolated urine cultures obtained. We used multivariable logistic regression to assess predictors of isolated cultures.RESULTSDuring the study period, 14,743 urine cultures were obtained (63.5 cultures per 1,000 patient days) during 11,820 patient admissions. Of these, 2,973 cultures (20.2%) were isolated cultures. Of the 61 CAUTIs identified, 31 (50.8%) were identified by an isolated culture. Predictors for having an isolated culture included male gender (adjusted odds ratio [aOR], 1.22; 95%; confidence interval [CI], 1.11–1.35], urinary catheterization (aOR, 2.15; 95% CI, 1.89–2.46), ICU admission (medical ICU aOR, 1.72; 95% CI, 1.47–2.00; surgical ICU aOR, 1.82; 95% CI, 1.51–2.19), and obtaining the urine culture ≥1 calendar day after admission (1–7 days aOR, 1.91; 95% CI. 1.71–2.12; &gt;7 days after admission aOR, 2.81; 95% CI, 2.37–3.34).CONCLUSIONSIsolated urine cultures are common in hospitalized patients, particularly in patients with urinary catheters and those in ICUs. Interventions targeting inpatient culturing practices may improve the diagnosis of urinary tract infections.Infect Control Hosp Epidemiol2017;38:455–460</jats:sec

Extended Volumetric Follow-up of Juvenile Pilocytic Astrocytomas Treated with Proton Beam Therapy

Purpose: To describe volume changes following proton beam therapy (PBT) for juvenile pilocytic astrocytoma (JPA), we analyzed post-PBT magnetic resonance imaging (MRI) to clarify survivorship, response rate, and the concept of pseudoprogression. Materials and Methods: Pediatric patients with a histologic diagnosis of JPA after a biopsy or subtotal resection and at least 4 post-PBT MRIs were retrospectively reviewed. After PBT, tumors were contoured on follow-up T1-contrasted MRIs, and 3-dimensional volumes were plotted against time, with thresholds for progressive disease and partial response. Patterns of response, pseudoprogression, and progression were uncovered. Post-PBT clinical course was described by the need for further intervention and survivorship. Results: Fifteen patients with a median of 10 follow-up MRIs made up this report: 60% were heavily pretreated with multiple lines of chemotherapy, and 67% had undergone subtotal resection. With a median follow-up of 55.3 months after a median of 5400 centigray equivalents PBT, estimates of 5-year overall survival and intervention-free survival were 93% and 72%, respectively. The crude response rate of 73% included pseudoprogressing patients, who comprised 20% of the entire cohort; the phenomenon peaked between 3 and 8 months and resolved by 18 months. One nonresponder expired from progression. Post-PBT intervention was required in 53% of patients, with 1 patient resuming chemotherapy. There were no further resections or radiotherapy. One patient developed acute lymphoblastic leukemia, and another developed biopsy-proven radionecrosis. Conclusion: The PBT for inoperable/progressive JPA provided 72% 5-year intervention-free survival in heavily pretreated patients. Although most patients responded, 20% demonstrated pseudoprogression. The need for post-PBT surveillance for progression and treatment-induced sequelae should not be underestimated in this extended survivorship cohort

Generalised dimensions of measures on almost self-affine sets

We establish a generic formula for the generalised q-dimensions of measures supported by almost self-affine sets, for all q>1. These q-dimensions may exhibit phase transitions as q varies. We first consider general measures and then specialise to Bernoulli and Gibbs measures. Our method involves estimating expectations of moment expressions in terms of `multienergy' integrals which we then bound using induction on families of trees

Algebraic entropy for semi-discrete equations

We extend the definition of algebraic entropy to semi-discrete (difference-differential) equations. Calculating the entropy for a number of integrable and non integrable systems, we show that its vanishing is a characteristic feature of integrability for this type of equations

Minimal immersions of closed surfaces in hyperbolic three-manifolds

We study minimal immersions of closed surfaces (of genus $g \ge 2$) in hyperbolic 3-manifolds, with prescribed data $(\sigma, t\alpha)$, where $\sigma$ is a conformal structure on a topological surface $S$, and $\alpha dz^2$ is a holomorphic quadratic differential on the surface $(S,\sigma)$. We show that, for each $t \in (0,\tau_0)$ for some $\tau_0 > 0$, depending only on $(\sigma, \alpha)$, there are at least two minimal immersions of closed surface of prescribed second fundamental form $Re(t\alpha)$ in the conformal structure $\sigma$. Moreover, for $t$ sufficiently large, there exists no such minimal immersion. Asymptotically, as $t \to 0$, the principal curvatures of one minimal immersion tend to zero, while the intrinsic curvatures of the other blow up in magnitude.Comment: 16 page

Discontinuation of reflex testing of stool samples for vancomycin-resistant enterococci resulted in increased prevalence

Discontinuation of reflex testing stool submitted for Clostridium difficile testing for vancomycin-resistant enterococci (VRE) led to an increase of patients with healthcare-associated VRE bacteremia and bacteriuria (2.1 versus 3.6 per 10,000 patient days; p<0.01 ). Cost-benefit analysis showed reflex screening and isolation of VRE reduced hospital costs

New Method for Phase transitions in diblock copolymers: The Lamellar case

A new mean-field type theory is proposed to study order-disorder transitions (ODT) in block copolymers. The theory applies to both the weak segregation (WS) and the strong segregation (SS) regimes. A new energy functional is proposed without appealing to the random phase approximation (RPA). We find new terms unaccounted for within RPA. We work out in detail transitions to the lamellar state and compare the method to other existing theories of ODT and numerical simulations. We find good agreements with recent experimental results and predict that the intermediate segregation regime may have more than one scaling behavior.Comment: 23 pages, 8 figure