A New Large N Expansion for General Matrix-Tensor Models

We define a new large $N$ limit for general $\text{O}(N)^{R}$ or $\text{U}(N)^{R}$ invariant tensor models, based on an enhanced large $N$ scaling of the coupling constants. The resulting large $N$ expansion is organized in terms of a half-integer associated with Feynman graphs that we call the index. This index has a natural interpretation in terms of the many matrix models embedded in the tensor model. Our new scaling can be shown to be optimal for a wide class of non-melonic interactions, which includes all the maximally single-trace terms. Our construction allows to define a new large $D$ expansion of the sum over diagrams of fixed genus in matrix models with an additional $\text{O}(D)^{r}$ global symmetry. When the interaction is the complete vertex of order $R+1$, we identify in detail the leading order graphs for $R$ a prime number. This slightly surprising condition is equivalent to the complete interaction being maximally single-trace.Comment: 57 pages, 20 figures (additional discussion in Sec. 4.1.1. and additional figure (Fig. 5)

Modeling Framework and Software Tools for Walking Robots

In research on passive dynamic walking, the aim is to study and design robots that walk naturally, i.e., with little or no control effort. McGeer [1] and others (e.g. [2, 3]) have shown that, indeed, robots can walk down a shallow slope with no actuation, only powered by gravity.\ud In this work, we derive mathematical models of walking ro- bots to better understand the dynamics that determine the walking behavior, and to design controllers that e.g. in- crease robustness against changing environments. We use the port-Hamiltonian framework, as it has the advantage of explicitly showing energy-flows inside and into the system. Thus, it allows a direct efficiency study as well as the possi- bility to connect external elements in a ‘physical’ way using ports, instead of using just torque/force signals

Abelian Surfaces over totally real fields are Potentially Modular

We show that abelian surfaces (and consequently curves of genus 2) over totally real fields are potentially modular. As a consequence, we obtain the expected meromorphic continuation and functional equations of their Hasse--Weil zeta functions. We furthermore show the modularity of infinitely many abelian surfaces A over Q with End_C(A)=Z. We also deduce modularity and potential modularity results for genus one curves over (not necessarily CM) quadratic extensions of totally real fields.Comment: 285 page

A frequent variant in the human bile salt export pump gene ABCB11 is associated with hepatitis C virus infection, but not liver stiffness in a German population

Background: The human ATP-binding cassette, subfamily B, member 11 (ABCB11) gene encodes the bile salt export pump, which is exclusively expressed at the canalicular membrane of hepatocytes. A frequent variant in the coding region, c.1331 T > C, leading to the amino acid exchange p.V444A, has been associated with altered serum bile salt levels in healthy individuals and predisposes homozygous carriers of the [C] allele for obstetric cholestasis. Recently, elevated bile salt levels were shown to be significantly associated with rates and risk of cirrhosis in patients with chronic hepatitis C virus (HCV) infection treated with pegylated interferon-alpha2 and ribavirin, suggesting a potential role for bile salt levels in HCV treatment outcomes and in the fibrogenic evolution of HCV-related liver disease. The aim of this study was to investigate a possible association of ABCB11 c.1331 T > C with hepatitis C virus (HCV) infection and fibrosis stages as assessed by non-invasive transient elastography in a German cohort of patients. Methods: ABCB11 c.1331 T > C genotype was determined by allelic discrimination assay in 649 HCV infected cases and 413 controls. Overall, 444 cases were staged for fibrotic progression by measurement of liver stiffness. Results: Homo- or heterozygous presence of the frequent [C] allele was associated with HCV positivity (OR = 1.41, CI = 1.02 - 1.95, p = 0.037). No association was detectable between the ABCB11 c.1331 T > C genotype and increased liver stiffness. Conclusions: Our data confirm that homozygous presence of the major [C] allele of ABCB11 c.1331 T > C is a genetic susceptibility factor for HCV infection, but not for liver fibrosis

Stability Criteria for Breached Pair Superfluidity

We present simple, concrete, two-fermion models that exhibit thermodynamically stable isotropic translationally-invariant gapless superfluid states (breached pair superfluidity). The mass ratio between the components and the momentum structure of the interaction are crucial for determining the stability of such states: Idealized, momentum-independent (``contact'') interactions are insufficient.Comment: 5 pages, REVTeX4. Minor updates in response to comments. References adde

Counter-Narratives of La Raza Voices: An Exploration of the Personal and Professional Lived Experiences of Mexican-American/Chicana/O Faculty at California Catholic Institutions of Higher Education

Faculty members of color time and again encounter the greatest number of challenges and barriers (e.g., discrimination, isolation, marginalization, tokenism, inundated with workloads and service commitments, devalued research, and delayed promotion and tenure) in both entering academia and succeeding within academia. The purpose of this study was to explore the personal and professional lived experiences of eight self-identified native-born Mexican-American and Chicana/o tenured and tenure-track faculty members employed at four California Catholic institutions of higher education. This study utilized a qualitative narrative methodology employing the critical race tenets of counter-storytelling and the permanence of racism. Through use of this methodology, La Raza counter-story narratives shed light on various degrees of racism pertaining to their social and cultural climate, tenure and promotion process, and level of job satisfaction as ethnic minority faculty members in Catholic higher education. Themes elicited from La Raza faculty narratives were compared against the associated master narratives. Although La Raza participants\u27 lived experiences marginally substantiated previous findings related to faculty of color, their narratives enhanced limited findings with more depth and detail specific to Mexican-American and Chicana/o faculty in Catholic higher education. In addition, La Raza faculty provided numerous recommendations to assist Mexican-American and Chicana/o scholars in their pursuit of academic careers in Catholic higher education; current Mexican-American and Chicana/o faculty toward tenure and promotion; and academic administrators in their recruitment, promotion, and retention of Mexican-American and Chicana/o faculty in Catholic higher education. Apparent in their counter-story narratives, each La Raza participant has made personal and professional commitments and contributions to sustain the cultures of both their self-identified ethnicity and of their university