Life Cycle of \u3ci\u3eIsoperla Lata\u3c/i\u3e (Plecoptera: Perlodidae) in a Central Wisconsin Trout Stream

Monthly qualitative samples of Isoperla lata Frison were made from January 1992 to June 1993 in Ripley Creek, a small second order trout stream in Lincoln County Wisconsin. Additional collecting and an in-stream hatching experiment were conducted in 1994. This species exhibited an S1 (slow) univoltine life cycle. Emergence was synchronous and occurred in late April through early May when stream temperatures in the field were approximately 9-14° C and laboratory stream temperatures were 7-17° C. Laboratory longevity was 2-25 (x = 18.2 ± 4.51) days for males and 7-39 (x = 21.7 ± 5.35) days for females. Mean fecundity of dissected females was 322 ± 122 eggs/female. Females did not deposit egg masses in the laboratory until being held together with males inside modified screened plastic containers. Field-collected females did not have eggs. The egg shape was ovoid and circular in cross section. Mature eggs were light brown and measured 371.7 ± 12.6 mm and 260.7 ± 10.2 mm in length and width respectively. Eggs required a 40-46 day in-stream incubation period and first instar nymphs hatched syn- chronously over a two day period when stream temperature reached 20°C. Nymphal growth was nearly exponential from June to January and then declined until emergence. The greatest growth increment occurred between June and October and the average maximum size attained occurred in February. Males and females had approximately 18 and 19 instars respectively. Nymphs were primarily carnivorous throughout development and fed on larval Chironomidae, Ephemeroptera, and Plecoptera

Theoretical and experimental studies of error in square-law detector circuits

Square law detector circuits to determine errors from the ideal input/output characteristic function were investigated. The nonlinear circuit response is analyzed by a power series expansion containing terms through the fourth degree, from which the significant deviation from square law can be predicted. Both fixed bias current and flexible bias current configurations are considered. The latter case corresponds with the situation where the mean current can change with the application of a signal. Experimental investigations of the circuit arrangements are described. Agreement between the analytical models and the experimental results are established. Factors which contribute to differences under certain conditions are outlined

Mean-field calculation of critical parameters and log-periodic characterization of an aperiodic-modulated model

We employ a mean-field approximation to study the Ising model with aperiodic modulation of its interactions in one spatial direction. Two different values for the exchange constant, $J_A$ and $J_B$, are present, according to the Fibonacci sequence. We calculated the pseudo-critical temperatures for finite systems and extrapolate them to the thermodynamic limit. We explicitly obtain the exponents $\beta$, $\delta$, and $\gamma$ and, from the usual scaling relations for anisotropic models at the upper critical dimension (assumed to be 4 for the model we treat), we calculate $\alpha$, $\nu$, $\nu_{//}$, $\eta$, and $\eta_{//}$. Within the framework of a renormalization-group approach, the Fibonacci sequence is a marginal one and we obtain exponents which depend on the ratio $r \equiv J_B/J_A$, as expected. But the scaling relation $\gamma = \beta (\delta -1)$ is obeyed for all values of $r$ we studied. We characterize some thermodynamic functions as log-periodic functions of their arguments, as expected for aperiodic-modulated models, and obtain precise values for the exponents from this characterization.Comment: 17 pages, including 9 figures, to appear in Phys. Rev.

Recurrence Relations for Strongly q-Log-Convex Polynomials

We consider a class of strongly q-log-convex polynomials based on a triangular recurrence relation with linear coefficients, and we show that the Bell polynomials, the Bessel polynomials, the Ramanujan polynomials and the Dowling polynomials are strongly q-log-convex. We also prove that the Bessel transformation preserves log-convexity.Comment: 15 page

Effect of water-wall interaction potential on the properties of nanoconfined water

Much of the understanding of bulk liquids has progressed through study of the limiting case in which molecules interact via purely repulsive forces, such as a hard-core potential. In the same spirit, we report progress on the understanding of confined water by examining the behavior of water-like molecules interacting with planar walls via purely repulsive forces and compare our results with those obtained for Lennard-Jones (LJ) interactions between the molecules and the walls. Specifically, we perform molecular dynamics simulations of 512 water-like molecules which are confined between two smooth planar walls that are separated by 1.1 nm. At this separation, there are either two or three molecular layers of water, depending on density. We study two different forms of repulsive confinements, when the interaction potential between water-wall is (i) $1/r^9$ and (ii) WCA-like repulsive potential. We find that the thermodynamic, dynamic and structural properties of the liquid in purely repulsive confinements qualitatively match those for a system with a pure LJ attraction to the wall. In previous studies that include attractions, freezing into monolayer or trilayer ice was seen for this wall separation. Using the same separation as these previous studies, we find that the crystal state is not stable with $1/r^9$ repulsive walls but is stable with WCA-like repulsive confinement. However, by carefully adjusting the separation of the plates with $1/r^9$ repulsive interactions so that the effective space available to the molecules is the same as that for LJ confinement, we find that the same crystal phases are stable. This result emphasizes the importance of comparing systems only using the same effective confinement, which may differ from the geometric separation of the confining surfaces.Comment: 20 pages, 10 figure

Comparing and characterizing some constructions of canonical bases from Coxeter systems

The Iwahori-Hecke algebra $\mathcal{H}$ of a Coxeter system $(W,S)$ has a "standard basis" indexed by the elements of $W$ and a "bar involution" given by a certain antilinear map. Together, these form an example of what Webster calls a pre-canonical structure, relative to which the well-known Kazhdan-Lusztig basis of $\mathcal{H}$ is a canonical basis. Lusztig and Vogan have defined a representation of a modified Iwahori-Hecke algebra on the free $\mathbb{Z}[v,v^{-1}]$-module generated by the set of twisted involutions in $W$, and shown that this module has a unique pre-canonical structure satisfying a certain compatibility condition, which admits its own canonical basis which can be viewed as a generalization of the Kazhdan-Lusztig basis. One can modify the parameters defining Lusztig and Vogan's module to obtain other pre-canonical structures, each of which admits a unique canonical basis indexed by twisted involutions. We classify all of the pre-canonical structures which arise in this fashion, and explain the relationships between their resulting canonical bases. While some of these canonical bases are related in a trivial fashion to Lusztig and Vogan's construction, others appear to have no simple relation to what has been previously studied. Along the way, we also clarify the differences between Webster's notion of a canonical basis and the related concepts of an IC basis and a $P$-kernel.Comment: 32 pages; v2: additional discussion of relationship between canonical bases, IC bases, and P-kernels; v3: minor revisions; v4: a few corrections and updated references, final versio

Estrategias de formulación de los mercados de abasto y su influencia en la sociedad y cultura

Los mercados de abasto es una de las infraestructuras más antiguas de comercialización que convive con el retail moderno, manteniendo su posicionamiento, gracias no solo a la ventaja competitiva del producto fresco sino a los impactos sociales y culturales que generan. Por otro lado los supermercados y su gran desarrollo logístico operacional y fuerte crecimiento, han modificado los hábitos de compra del consumidor, con la creación de distintos formatos de venta, posicionándose cada vez más en la preferencia de compra, pudiéndose perder ese potencial beneficio sociocultural, por lo que los mercados de abasto tradicionales necesitan implementar nuevas estrategias que les permita seguir desarrollando esos aspectos relevantes de la sociedad, recuperando sus orígenes de ser edificaciones potencialmente influyentes de su entorno, a través de intervenciones que generan vinculaciones sociales y culturales, encontrándose en la investigación soluciones como: Beneficios sociales a través de la integración estratégica de comerciantes y vecinos, Beneficios urbanos a través de la integración con su entorno, Beneficios culturales a través de nuevos servicios con valor agregado, mejoras de los servicios internos implementando el diseño emocional y merchandising en la exhibición

Moxalactam Therapy for Obstetric and Gynecologic Infections

Moxalactam, a new cephalosporin antibiotic with a broad spectrum of activity, was evaluated for safety and therapeutic efficacy in the treatment of genital tract infections in women. Fifty-three patients with postpartum endometritis or acute or chronic pelvic inflammatory disease were treated with 2 g of moxalactam iv every 8 hr, usually for five days or longer. Appropriate cultures of peripheral blood, endometrium, cul-de-sac aspirates, urine, wound, and endocervix (only for Neisseria gonorrhoeae) were performed. Overall, 90.6% (48 of 53) of the patients were successfully treated with moxalactam - 86.2% (25 of 29) and 95.8% (23 of 24) of the patients with endometritis and pelvic inflammatory disease, respectively. Therapy failed in one of five bacteremic patients with endometritis. Of all the bacteria isolated from appropriate culture sites, 58% (224 of 383) were anaerobes, with anaerobic gram-negative rods - particularly Bacteroides bivius-and gram-positive cocci being predominant. Of 206 anaerobic strains tested with moxalactam by agar dilution techniques, 82% (169 of 206) were susceptible (minimal inhibitory concentration [MIC], ⩽8 μg/ml), 11.6% (24 of 206) were moderately susceptible (MIC, 16-32 μg/ml), and 6.3% (13 of 206) were resistant (MIC, ⩾64 μg/ml). Among the aerobic isolates, enterococci were uniformly resistant. Thus, moxalactam performed well as a single agent in this open clinical trail for women with infections of the genital trac