Dominance Over N

Abstract.This paper provides an overview of the b-dominance order over the natural numbers, N, using the base b expansion of natural numbers. The b-dominance order is an accessible partially-ordered set that is less complex than the divisor relation but more complex than ≤; thus, it supplies a good medium through which an undergraduate can be exposed to the subject of order theory. Here we discuss many ideas in order theory, including the Poincaré polynomial and the Möbius function. Acknowledgements: The authors thank the M.J. Murdock Charitable Trust and the Pacific Lutheran University Division of Natural Sciences for their generous support. They would also like to extend their thanks to Dr. Tom Edgar for the project idea and all his help throughout their summer program. Page 24 RHIT Undergrad. Math. J., Vol. 14, no. 2

System Theory, Operator Models and Scattering: The Time-Varying Case

It is well known that linear system theory, Lax-Phillips scattering theory, and operator model theory for a contraction operator are all intimately related. A common thread in all three theories is a contractive, analytic, operator-valued function on the unit disk W(z) having a representation of the form W(z) = D + zC(I − zA)−1B, known, depending on the context, as the transfer function, the scattering function, or the characteristic function. We present the time-varing analogue of this framework. Also included is a time-varying analogue of the Abstract Interpolation Problem of Katsnelson-Kheifets-Yuditskii

The Two-Sided Residue Interpolation Problem in the Stieltjes Class

The general two-sided directional interpolation problem in the Stieltjes class for matrix functions is solved. An explicit description of all solutions is presented in terms of the original data. The method is based on the reduction of this problem to the solution of homogeneous interpolation problems with symmetries for rationalmatrix functions

The Two-Sided Residue Interpolation Problem in the Stieltjes Class

The general two-sided directional interpolation problem in the Stieltjes class for matrix functions is solved. An explicit description of all solutions is presented in terms of the original data. The method is based on the reduction of this problem to the solution of homogeneous interpolation problems with symmetries for rationalmatrix functions

Incidence of surgical site infection following mastectomy with and without immediate reconstruction using private insurer claims data

OBJECTIVE: The National Healthcare Safety Network classifies breast operations as clean procedures with an expected 1–2% surgical site infection (SSI) incidence. We assessed differences in SSI incidence following mastectomy with and without immediate reconstruction in a large, geographically diverse population. DESIGN: Retrospective cohort study. PATIENTS: Commercially-insured women aged 18–64 years with ICD-9-CM procedure or CPT-4 codes for mastectomy from 1/1/2004–12/31/2011. METHODS: Incident SSIs within 180 days after surgery were identified by ICD-9-CM diagnosis codes. The incidence of SSI after mastectomy +/− immediate reconstruction was compared by the chi-square test. RESULTS: From 2004–2011, 18,696 mastectomy procedures among 18,085 women were identified, with immediate reconstruction in 10,836 (58%) procedures. The 180-day incidence of SSI following mastectomy with or without reconstruction was 8.1% (1,520/18,696). Forty-nine percent of SSIs were identified within 30 days post-mastectomy, 24.5% between 31–60 days, 10.5% between 61–90 days, and 15.7% between 91–180 days. The incidence of SSI was 5.0% (395/7,860) after mastectomy-only, 10.3% (848/8,217) after mastectomy plus implant, 10.7% (207/1,942) after mastectomy plus flap, and 10.3% (70/677) after mastectomy plus flap and implant (p<0.001). The SSI risk was higher after bilateral compared with unilateral mastectomy with (11.4% vs. 9.4%, p=0.001) and without (6.1% vs. 4.7%, p=0.021) immediate reconstruction. CONCLUSIONS: SSI incidence was two-fold higher after mastectomy with immediate reconstruction than after mastectomy alone. Only 49% of SSIs were coded within 30 days after operation. Our results suggest stratification by procedure type will facilitate comparison of SSI rates after breast operations between facilities

Second moment of the pion's distribution amplitude

We present preliminary results from the QCDSF/UKQCD collaborations for the second moment of the pion's distribution amplitude with two flavours of dynamical fermions. We use nonperturbatively determined renormalisation coefficients to convert our results to the MSbar scheme at 5 GeV^2. Employing a linear chiral extrapolation from our large pion masses >550 MeV, we find =0.281(28), leading to a value of a_2=0.236(82) for the second Gegenbauer moment.Comment: 6 pages, 5 figures, 1 table. To appear in: Procs. of the Workshop on Light-Cone QCD and Nonperturbative Hadron Physics 2005 (LC 2005), Cairns, Australia, 200

Effects of Aminocyclopyrachlor Herbicide on Downy Brome (Bromus tectorum) Seed Production under Field Conditions

Previous research has shown that pyridine growth regulator herbicides can affect seed production in annual grasses including downy brome, Japanese brome, wheat, and other cereal grain crops. Aminocyclopyrachlor is a pyridine carboxylic acid growth regulator herbicide that has recently been registered for broadleaf weed and brush control in nonagricultural areas, which may help facilitate release of native perennial grasses in native plant restoration sites. The influence of aminocyclopyrachlor on downy brome seed production was evaluated at multiple application rates and timings under controlled field conditions. The effect of aminocyclopyrachlor on seed production was compared with aminopyralid, another pyridine growth regulator herbicide. When applied to downy brome plants in the early vegetative stage (EPOST) at approximately 580 growing degree days (GDD), aminocyclopyrachlor at 320 g ae ha⁻¹ reduced seed germination by 50 to 88% in the first and second study years, respectively. Aminopyralid reduced seed germination by 94% in the first study year, but only 20% in the second year. When applied to downy brome plants in the early heading stage at approximately 1,235 GDD (LPOST), aminocyclopyrachlor at 320 g ae ha⁻¹ reduced seed germination by 100% both years. Aminopyralid reduced seed germination by 95% in the first year, and 81% in the second year. Other than the observed reduction in seed germination, herbicides did not produce any visible changes in downy brome aboveground plant growth or development. Because downy brome seeds are relatively short-lived in soil, aminocyclopyrachlor and aminopyralid applications to downy brome–infested rangelands and other natural areas could result in reductions in downy brome population densities over time. No published data exist on the effect of aminocyclopyrachlor on seed production of desirable perennial grasses in natural ecosystems, thereby suggesting the need for further research.Keywords: Rangeland, Native plant communities, Invasive species, Chemical control, Pyridine carboxylic acid, Growth regulator herbicide, Growing degree day, Pyridine herbicideThis is the publisher’s final pdf. The published article is copyrighted by the Weed Science Society of America and can be found at: http://wssajournals.org/loi/ipsm. The author has paid this publisher's Open Access fee

Antipsychotic adherence, switching, and health care service utilization among Medicaid recipients with schizophrenia

Objective: To evaluate health care resource utilization in patients with schizophrenia who continued newly prescribed antipsychotic medications, compared with those switching to different treatments. Methods: Adults with schizophrenia in the California Medicaid (MediCal) database who initiated treatment with index medications in 1998–2001, were classified as having: 1) abandoned antipsychotic medications; 2) switched to another medication; or 3) continued with the index antipsychotic, for up to 6 months after the index date. Results: Of 2300 patients meeting eligibility criteria, 1382 (60.1%) continued index medications, 480 (20.9%) switched, and 438 (19.0%) abandoned antipsychotic treatment. Utilization in several resource categories occurred significantly more frequently among patients whose regimens were switched (vs those continuing index medications). These included using psychiatric (24.2% vs 14.5%; P \u3c 0.001) or nonpsychiatric (31.5% vs 24.3%; P \u3c 0.05) emergency services; being admitted to a hospital (10.6% vs 7.4%; P \u3c 0.05); making nonpsychiatric outpatient hospital visits (43.3% vs 36.4%; P \u3c 0.05) or nonpsychiatric physician visits (62.7% vs 56.4%; P \u3c 0.05); and using other outpatient psychiatric (53.3% vs 40.7%; P \u3c 0.001) or nonpsychiatric (82.7% vs 74.6%; P \u3c 0.001) services. Conclusions: Switching antipsychotic medications is associated with significantly increased health care resource utilization (vs continuing treatment)

HIV-infected sex workers with beneficial HLA-variants are potential hubs for selection of HIV-1 recombinants that may affect disease progression

Cytotoxic T lymphocyte (CTL) responses against the HIV Gag protein are associated with lowering viremia; however, immune control is undermined by viral escape mutations. The rapid viral mutation rate is a key factor, but recombination may also contribute. We hypothesized that CTL responses drive the outgrowth of unique intra-patient HIV-recombinants (URFs) and examined gag sequences from a Kenyan sex worker cohort. We determined whether patients with HLA variants associated with effective CTL responses (beneficial HLA variants) were more likely to carry URFs and, if so, examined whether they progressed more rapidly than patients with beneficial HLA-variants who did not carry URFs. Women with beneficial HLA-variants (12/52) were more likely to carry URFs than those without beneficial HLA variants (3/61) (p &lt; 0.0055; odds ratio = 5.7). Beneficial HLA variants were primarily found in slow/standard progressors in the URF group, whereas they predominated in long-term non-progressors/survivors in the remaining cohort (p = 0.0377). The URFs may sometimes spread and become circulating recombinant forms (CRFs) of HIV and local CRF fragments were over-represented in the URF sequences (p &lt; 0.0001). Collectively, our results suggest that CTL-responses associated with beneficial HLA variants likely drive the outgrowth of URFs that might reduce the positive effect of these CTL responses on disease progression

On the class SI of J-contractive functions intertwining solutions of linear differential equations

In the PhD thesis of the second author under the supervision of the third author was defined the class SI of J-contractive functions, depending on a parameter and arising as transfer functions of overdetermined conservative 2D systems invariant in one direction. In this paper we extend and solve in the class SI, a number of problems originally set for the class SC of functions contractive in the open right-half plane, and unitary on the imaginary line with respect to some preassigned signature matrix J. The problems we consider include the Schur algorithm, the partial realization problem and the Nevanlinna-Pick interpolation problem. The arguments rely on a correspondence between elements in a given subclass of SI and elements in SC. Another important tool in the arguments is a new result pertaining to the classical tangential Schur algorithm.Comment: 46 page