Vertex-Coloring with Star-Defects

Defective coloring is a variant of traditional vertex-coloring, according to which adjacent vertices are allowed to have the same color, as long as the monochromatic components induced by the corresponding edges have a certain structure. Due to its important applications, as for example in the bipartisation of graphs, this type of coloring has been extensively studied, mainly with respect to the size, degree, and acyclicity of the monochromatic components. In this paper we focus on defective colorings in which the monochromatic components are acyclic and have small diameter, namely, they form stars. For outerplanar graphs, we give a linear-time algorithm to decide if such a defective coloring exists with two colors and, in the positive case, to construct one. Also, we prove that an outerpath (i.e., an outerplanar graph whose weak-dual is a path) always admits such a two-coloring. Finally, we present NP-completeness results for non-planar and planar graphs of bounded degree for the cases of two and three colors

Shrinkage of Rio Grande silvery minnow after preservation in formalin and storage in ethanol

Understanding how the preservation process affects fish morphology is important for studies that use museum collections as voucher specimens. Sixty-nine Rio Grande silvery minnows (standard length [SL] 32.14–81.65 mm) were observed over 545 days during a formalin-to-water-to-ethanol preservation procedure. Median standard length decreased by the end of each preservation step; specimens shrank 1.06 mm in formalin solution, 1.97 mm in 35% ethanol, 2.17 mm in 50% ethanol, and 2.48 mm in 70% ethanol. Peak shrinkage occurred at 365 d, with a median decrease of 3.86 mm (SL 29.57–75.98 mm). After 545 days, Rio Grande silvery minnows began to increase in length, exhibiting a median shrinkage of 2.04 mm from live length. Research on museum specimens that includes morphological measurements should consider that changes in length or body shape may influence or hinder the ability to detect changes in morphology over time.Se observaron 69 especímenes de carpa chamizal (de longitud estándar entre 32.14–81.65 mm) durante el procedimiento de conservación de formalina a agua y etanol que duró 545 días. La longitud estándar media disminuyó al final de cada paso de conservación; la solución de formalina encogió las muestras 1.06 mm, el etanol al 35% las encogió 1.97 mm, el etanol al 50% las encogió 2.17 mm y el etanol al 70% las encogió 2.48 mm. La disminución máxima se produjo a los 365 días con una reducción media de tamaño de 3.86 mm (de longitud estándar entre 29.57–75.98 mm). Después de 545 días, los especímenes de carpa chamizal comenzaron a aumentar en longitud con una reducción media de tamaño de 2.04 mm de la longitud original. Las investigaciones sobre especímenes de museos que incluyan medidas morfológicas deberán considerar que los cambios en la longitud o en la forma del cuerpo podrían influir o dificultar la detección de cambios morfológicos a lo largo del tiempo

Local chromatic number of quadrangulations of surfaces

The local chromatic number of a graph G, as introduced in [4], is the minimum integer k such that G admits a proper coloring (with an arbitrary number of colors) in which the neighborhood of each vertex uses less than k colors. In [17] a connection of the local chromatic number to topological properties of (a box complex of) the graph was established and in [18] it was shown that a topological condition implying the usual chromatic number being at least four has the stronger consequence that the local chromatic number is also at least four. As a consequence one obtains a generalization of the following theorem of Youngs [19]: If a quadrangulation of the projective plane is not bipartite it has chromatic number four. The generalization states that in this case the local chromatic number is also four. Both papers [1] and [13] generalize Youngs’ result to arbitrary non-orientable surfaces replacing the condition of the graph being not bipartite by a more technical condition of an odd quadrangulation. This paper investigates when these general results are true for the local chromatic number instead of the chromatic number. Surprisingly, we find out that (unlike in the case of the chromatic number) this depends on the genus of the surface. For the non-orientable surfaces of genus at most four, the local chromatic number of any odd quadrangulation is at least four, but this is not true for non-orientable surfaces of genus 5 or higher. We also prove that face subdivisions of odd quadrangulations and Fisk triangulations of arbitrary surfaces exhibit the same behavior for the local chromatic number as they do for the usual chromatic number

Gender based water violence: cross cultural evidence of severe harm associated with water insecurity for women and girls

We examined how study participants in Indonesia and Peru viewed the relationship between water insecurity and women's health via thematic analysis of interviews and focus groups. Participants reported that water insecurity led to vaginal infections, miscarriage, premature births, uterine prolapse, poor nutrition, restricted economic opportunities, and intergenerational cycles of poverty. Participants in both countries stated that extreme burdens associated with water insecurity should be categorized as violence. Based on these findings, we developed the concept of “gender-based water violence,” defined as the spectrum of stressors associated with water insecurity that are so severe as to threaten human health and well-being, particularly that of women and girls

Seasonal variation in reproductive condition of the Peco Bluntnose Shiner (\u3ci\u3eNotropis simus pecosensis\u3c/i\u3e)

Reproductive strategies vary among freshwater fishes. Information on reproductive characteristics is important for water managers’ efforts to protect and recover imperiled species. We describe aspects of the reproductive ecology of Pecos Bluntnose Shiner (Notropis simus pecosensis). We determined gonadosomatic index, examined ovarian condition, and counted mature ova to determine the seasonal reproductive timing and duration of Pecos Bluntnose Shiner in the Pecos River, New Mexico. Monthly changes in gonadosomatic index, ovarian stage, and number of mature ova per female suggest that Pecos Bluntnose Shiner has a reproductive season extending from April through September, with a peak occurring in June and July. In July, 93% (n = 44) of female Pecos Bluntnose Shiner were in reproductive condition, regardless of size. The highest number of mature ova counted (1498) was observed in a 59.5-mm (standard length) female from June 2009. Peak spawning activity coincides with sustained water releases from reservoirs; these releases have higher peaks and longer duration than natural rainfall events. Results of this study provide important insight on the reproductive biology of a threatened fish and may be useful in long-term conservation planning.Las estrategias reproductivas varían entre los peces de agua dulce. La información sobre las características reproductivas es importante para los gestores de los ambientes acuáticos con el fin de proteger y recuperar especies en peligro. Describimos aspectos de la ecología reproductiva de la carpa (Notropis simus pecosensis). Determinamos el índice gonadosomático, las condiciones del ovario, y contamos los óvulos maduros para determinar la temporada de reproducción y la duración de las carpas en el Río Pecos, Nuevo México. Los cambios mensuales en el índice gonadosomático, la etapa de ovario y el número de óvulos maduros por hembra sugirieron que las carpas tienen una temporada reproductiva desde abril hasta septiembre, con un pico entre junio y julio. En julio, el 93% (n = 44) de las hembras se encontraron en condiciones reproductivas, independientemente de su tamaño. El mayor número de óvulos maduros contabilizados (1498) en una hembra de 59.5 mm (longitud estándar) fue en junio del 2009. El pico máximo de actividad de desove coincide con una liberación prolongada de agua de los embalses, con picos mayores y mayor duración que los eventos de lluvia naturales. Los resultados de este estudio proporcionan información importante sobre la biología reproductiva de un pez amenazado y pueden ser útiles en la planificación de su conservación a largo plazo

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Advertising media strategies in the film industry

The primary aim of this article is to estimate the multiple determinants of film advertising expenditures in four important media, namely television, press, outdoor and radio, in the UK. First, television advertising, the leading film advertising medium, is examined as part of a system of equations, capturing the interdependences between advertising, the number of screens on which films are initially shown and box office revenues. Then a reduced form model is put forward to reveal the determinants of film advertising in the four media. While major distribution companies have different preferences for the use of the alternative advertising media, results highlight the importance of quality signals, such as critical reviews, in determining advertising expenditures in the film industry. Moreover, advertising expenditures can themselves be considered to offer potential cinema goers signals of film quality

Fish Rescue during Streamflow Intermittency May Not Be Effective for Conservation of Rio Grande Silvery Minnow

Streamflow intermittency can reshape fish assemblages and present challenges to recovery of imperiled species. During streamflow intermittency, fish can be subjected to a variety of stressors, including exposure to crowding, high water temperatures, and low dissolved oxygen, resulting in sublethal effects or mortality. Rescue of fishes is often used as a conservation tool to mitigate the negative impacts of streamflow intermittency. The effectiveness of such actions is rarely evaluated. Here, we use multi-year water quality data collected from isolated pools during rescue of Rio Grande silvery minnow Hybognathus amarus, an endangered minnow. We examined seasonal and diel water quality patterns to determine if fishes are exposed to sublethal and critical water temperatures or dissolved oxygen concentrations during streamflow intermittency. Further, we determined survival of rescued Rio Grande silvery minnow for 3–5 weeks post-rescue. We found that isolated pool temperatures were much warmer (>40 °C in some pools) compared to upstream perennial flows, and had larger diel fluctuations, >10 °C compared to ~5 °C, and many pools had critically low dissolved oxygen concentrations. Survival of fish rescued from isolated pools during warmer months was <10%. Reactive conservation actions such as fish rescue are often costly, and in the case of Rio Grande silvery minnow, likely ineffective. Effective conservation of fishes threatened by streamflow intermittency should focus on restoring natural flow regimes that restore the natural processes under which fishes evolved