Specht modules and semisimplicity criteria for Brauer and Birman--Murakami--Wenzl Algebras

A construction of bases for cell modules of the Birman--Murakami--Wenzl (or B--M--W) algebra $B_n(q,r)$ by lifting bases for cell modules of $B_{n-1}(q,r)$ is given. By iterating this procedure, we produce cellular bases for B--M--W algebras on which a large abelian subalgebra, generated by elements which generalise the Jucys--Murphy elements from the representation theory of the Iwahori--Hecke algebra of the symmetric group, acts triangularly. The triangular action of this abelian subalgebra is used to provide explicit criteria, in terms of the defining parameters $q$ and $r$, for B--M--W algebras to be semisimple. The aforementioned constructions provide generalisations, to the algebras under consideration here, of certain results from the Specht module theory of the Iwahori--Hecke algebra of the symmetric group

Young-Onset Colorectal Cancer: Earlier Diagnoses or Increasing Disease Burden?

Colorectal cancer (CRC) incidence and mortality in the United States have changed strikingly in recent decades. Overall, CRC incidence decreased by >30% from 1975 (59.5 per 100,000) to 2013 (37.9 per 100,000). CRC mortality similarly declined from 28.1 per 100,000 in 1975 to 14.5 per 100,000 in 2013—nearly a 50% decrease.1 Screen-eligible populations, particularly those over age 65, have experienced the largest declines in incidence and mortality

Hecke algebras of finite type are cellular

Let \cH be the one-parameter Hecke algebra associated to a finite Weyl group $W$, defined over a ground ring in which ``bad'' primes for $W$ are invertible. Using deep properties of the Kazhdan--Lusztig basis of \cH and Lusztig's \ba-function, we show that \cH has a natural cellular structure in the sense of Graham and Lehrer. Thus, we obtain a general theory of ``Specht modules'' for Hecke algebras of finite type. Previously, a general cellular structure was only known to exist in types $A_n$ and $B_n$.Comment: 14 pages; added reference

Racial Disparities in Incidence of Young-Onset Colorectal Cancer and Patient Survival

Background & Aims: Increasing rates of young-onset colorectal cancer (CRC) have attracted substantial research and media attention, but we know little about racial disparities among younger adults with CRC. We examined racial disparities in young-onset CRC by comparing CRC incidence and relative survival among younger (<50-year-old) adults in 2 time periods. Methods: Using data from the Surveillance, Epidemiology, and End Results program of cancer registries, we estimated CRC incidence rates (per 100,000 persons 20–49 years old) from 1992 through 2014 for different periods (1992–1996 vs 2010–2014) and races (white vs black). Relative survival was calculated as the ratio of observed survival to expected survival in a comparable cancer-free population. Results: From 1992–1996 to 2010–2014, CRC incidence increased from 7.5 to 11.0 per 100,000 in white individuals and from 11.7 to 12.7 per 100,000 in black individuals. The increase in rectal cancer was larger in whites (from 2.7 to 4.5 per 100,000) than in blacks (from 3.4 to 4.0 per 100,000); in the 2010–2014 period, blacks and whites had similar rates of rectal cancer. Compared with whites, blacks had smaller increases in relative survival with proximal colon cancer but larger increases in survival with rectal cancer (from 55.3% to 70.8%). Conclusion: In an analysis of the Surveillance, Epidemiology, and End Results database, we found racial disparities in incidence of young-onset CRC and patient survival for cancer of the colon but minimal difference for rectal cancer. Well-documented and recent increases in young-onset CRC have largely been due to increases in rectal cancer, especially in whites

The Point of Origin of the Radio Radiation from the Unresolved Cores of Radio-Loud Quasars

Locating the exact point of origin of the core radiation in active galactic nuclei (AGN) would represent important progress in our understanding of physical processes in the central engine of these objects. However, due to our inability to resolve the region containing both the central compact object and the jet base, this has so far been difficult. Here, using an analysis in which the lack of resolution does not play a significant role, we demonstrate that it may be impossible even in most radio loud sources for more than a small percentage of the core radiation at radio wavelengths to come from the jet base. We find for 3C279 that $\sim85$ percent of the core flux at 15 GHz must come from a separate, reasonably stable, region that is not part of the jet base, and that then likely radiates at least quasi-isotropically and is centered on the black hole. The long-term stability of this component also suggests that it may originate in a region that extends over many Schwarzschild radii.Comment: 7 pages with 3 figures, accepted for publication in Astrophysics and Space Scienc

Patterns of Sociodemographic and Clinicopathologic Characteristics of Stages II and III Colorectal Cancer Patients by Age: Examining Potential Mechanisms of Young-Onset Disease

Background and Aims. As a first step toward understanding the increasing incidence of colorectal cancer (CRC) in younger (age < 50) populations, we examined demographic, clinicopathologic, and socioeconomic characteristics and treatment receipt in a population-based sample of patients newly diagnosed with stages II and III CRC. Methods. Patients were sampled from the National Cancer Institute's Patterns of Care studies in 1990/91, 1995, 2000, 2005, and 2010 (n=6,862). Tumor characteristics and treatment data were obtained through medical record review and physician verification. We compared sociodemographic and clinicopathologic characteristics and treatment patterns of younger (age < 50) and older (age 50-69, age ≥ 70) CRC patients. Results. Younger patients were more likely to be black (13%) and Hispanic (15%) than patients aged 50-69 years (11% and 10%, resp.) and ≥70 years (7% each). A larger proportion of young white (41%) and Hispanic (33%) patients had rectal tumors, whereas tumors in the right colon were the most common in young black patients (39%). The majority of younger patients received chemotherapy and radiation therapy, although receipt of microsatellite instability testing was suboptimal (27%). Conclusion. Characteristics of patients diagnosed with young-onset CRC differ considerably by race/ethnicity, with a higher proportion of black and Hispanic patients diagnosed at the age of < 50 years

A preliminary study of human amniotic membrane as a potential chondrocyte carrier

Purpose: To investigate the feasibility of using processed human amniotic membrane (HAM) to support the attachment and proliferation of chondrocytes in vitro which in turn can be utilised as a cell delivery vehicle in tissue engineering applications. Methods: Fresh HAM obtained from patients undergoing routine elective caesarean sections was harvested, processed and dried using either freeze drying (FD) or air drying (AD) methods prior to sterilisation by gamma irradiation. Isolated, processed and characterised rabbit autologous chondrocytes were seeded on processed HAM and cultured for up to three weeks. Cell attachment and proliferation were examined qualitatively using inverted brightfield microscopy. Results: Processed HAM appeared to allow cell attachment when implanted with chondrocytes. Although cells seeded on AD and FD HAM did not appear to attach as strongly as those seeded on glycerol preserved intact human amniotic membrane, these cells to be proliferated in cell culture conditions. Conclusion: Preliminary results show that processed HAM promotes chondrocyte attachment and proliferation

Tunneling from a correlated 2D electron system transverse to a magnetic field

We show that, in a magnetic field parallel to the 2D electron layer, strong electron correlations change the rate of tunneling from the layer exponentially. It results in a specific density dependence of the escape rate. The mechanism is a dynamical Mossbauer-type recoil, in which the Hall momentum of the tunneling electron is partly transferred to the whole electron system, depending on the interrelation between the rate of interelectron momentum exchange and the tunneling duration. We also show that, in a certain temperature range, magnetic field can enhance rather than suppress the tunneling rate. The effect is due to the magnetic field induced energy exchange between the in-plane and out-of-plane motion. Magnetic field can also induce switching between intra-well states from which the system tunnels, and a transition from tunneling to thermal activation. Explicit results are obtained for a Wigner crystal. They are in qualitative and quantitative agreement with the relevant experimental data, with no adjustable parameters.Comment: 16 pages, 9 figure