In this paper we describe the OpenGeoSys (OGS) project, which is a scientific open-source initiative for numerical simulation of thermo-hydro-mechanical-chemical processes in porous media. The basic ...concept is to provide a flexible numerical framework (using primarily the Finite Element Method (FEM)) for solving multifield problems in porous and fractured media for applications in geoscience and hydrology. To this purpose OGS is based on an object-oriented FEM concept including a broad spectrum of interfaces for pre- and postprocessing. The OGS idea has been in development since the mid-eighties. We provide a short historical note about the continuous process of concept and software development having evolved through Fortran, C, and C++ implementations. The idea behind OGS is to provide an open platform to the community, outfitted with professional software-engineering tools such as platform-independent compiling and automated benchmarking. A comprehensive benchmarking book has been prepared for publication. Benchmarking has been proven to be a valuable tool for cooperation between different developer teams, for example, for code comparison and validation purposes (DEVOVALEX and CO
2
BENCH projects). On one hand, object-orientation (OO) provides a suitable framework for distributed code development; however, the parallelization of OO codes still lacks efficiency. High-performance-computing efficiency of OO codes is subject to future research.
A particularly simple description of separability of quantum states arises naturally in the setting of complex algebraic geometry, via the Segre embedding. This is a map describing how to take ...products of projective Hilbert spaces. In this paper, we show that for pure states of
n
particles, the corresponding Segre embedding may be described by means of a directed hypercube of dimension
(
n
-
1
)
, where all edges are bipartite-type Segre maps. Moreover, we describe the image of the original Segre map via the intersections of images of the
(
n
-
1
)
edges whose target is the last vertex of the hypercube. This purely algebraic result is then transferred to physics. For each of the last edges of the Segre hypercube, we introduce an observable which measures geometric separability and is related to the trace of the squared reduced density matrix. As a consequence, the hypercube approach allows to measure entanglement, naturally relating bipartitions with
q
-partitions for any
q
≥
1
. We test our observables against well-known states, showing that these provide well-behaved and fine measures of entanglement.
Citizen science may be especially effective in urban landscapes due to the large pool of potential volunteers. However, there have been few evaluations of the contributions of citizen scientists to ...knowledge of biological communities in and around cities. To assess the effectiveness of citizen scientists' monitoring of species in urban areas, we compared butterfly data collected over 10 years in Chicago, Illinois (U.S.A.), and New York City, New York (U.S.A.). The dates, locations, and methods of data collection in Chicago were standardized, whereas data from New York were collected at any location at any time. For each city, we evaluated whether the number of observers, observation days (days on which observations were reported), and sampling locations were associated with the reported proportion of the estimated regional pool of butterfly species. We also compared the number of volunteers, duration of volunteer involvement, and consistency of sampling efforts at individual locations within each city over time. From 2001 to 2010, there were 73 volunteers in Chicago and 89 in New York. During this period, volunteers observed 86% and 89% of the estimated number of butterfly species present in Chicago and New York, respectively. Volunteers in New York reported a greater proportion of the estimated pool of butterfly species per year. In addition, more species were observed per volunteer and observation day in New York, largely due to the unrestricted sampling season in New York. Chicago volunteers were active for more years and monitored individual locations more consistently over time than volunteers in New York. Differences in monitoring protocol—especially length of sampling season and selection protocol for monitoring locations—influenced the relationship between species accrual and sampling effort, which suggests these factors are important in volunteer-based species-monitoring programs. La ciencia ciudadana puede ser especialmente efectiva en paisajes urbanos debido a la gran disponibilidad de voluntarios potenciales. Sin embargo, existen pocas evaluaciones de las contribuciones de los científicos ciudadanos al conocimiento de las comunidades biológicas en y alrededor de las ciudades. Para evaluar la efectividad del monitoreo de especies por científicos ciudadanos en áreas urbanas, comparamos los datos de mariposas recolectados a lo largo de 10 años en Chicago, Illinois (E.U.A.) y Nueva York, Nueva York (E.U.A.). Las fechas, localidades y métodos de recolección de datos en Chicago fueron estandarizadas, mientras que los datos de Nueva York fueron recolectados en cualquier localidad en cualquier tiempo. Para cada ciudad evaluamos si el número de observadores, días de observación (días en que se registraron las observaciones) y localidades de muestreo se asociaban con la proporción reportada de las especies de mariposas regionales. También comparamos el número de voluntarios, la duración de la participación de voluntarios y la consistencia de los esfuerzos de muestreo en localidades individuales en cada ciudad. De 2001 a 2010 hubo 73 voluntarios en Chicago y 89 en Nueva York. Durante ese período, los voluntarios observaron 86% y 89% del número estimado de especies de mariposas presentes en Chicago y Nueva York, respectivamente. Voluntarios en Nueva York reportaron una mayor proporción de la riqueza estimada de especies de mariposas por año. Adicionalmente, se observaron más especies por voluntario y día de observación en Nueva York, debido principalmente a la temporada de observación sin restricciones en Nueva York. Los voluntarios de Chicago fueron activos por más años y monitorearon localidades individuales más consistentemente en el tiempo que los voluntarios de Nueva York. Las diferencias en el protocolo de monitoreo - especialmente la duración de la estación de muestreo y el protocolo para la selección de localidades de monitoreo - influyeron en la relación entre el incremento de especies y el esfuerzo de muestreo, lo cual sugiere que estos factores son importantes en los programas de monitoreo de especies llevados a cabo por voluntarios.
Hydrothermal alteration can create low‐permeability zones, potentially resulting in elevated pore‐fluid pressures, within a volcanic edifice. Strength reduction by rock alteration and high pore‐fluid ...pressures have been suggested as a mechanism for edifice flank instability. Here we combine numerical models of multiphase heat transport and groundwater flow with a slope‐stability code that incorporates three‐dimensional distributions of strength and pore‐water pressure to address the following questions: (1) What permeability distributions and contrasts produce elevated pore‐fluid pressures in a stratovolcano? (2) What are the effects of these elevated pressures on flank stability? (3) Finally, what are the effects of magma intrusion on potential flank failure in an edifice? Simulation results show that under a range of plausible parameters, water tables in a stratovolcano can be elevated or perched. These elevated water tables result in universally lower stability (lower factor of safety) compared with equivalent dry edifices, indicating a higher likelihood of flank collapse. Low‐permeability (<1 × 10−17 m2) layers such as altered pyroclastic deposits or breccias can result in locally saturated regions (perched water) and lower factors of safety near the ground surface but may actually reduce liquid water saturation and pore pressures in the core of the edifice and thus may favor small, shallow collapses over larger, deeper collapses. Magma intrusion into the base of the edifice increases pore‐fluid pressures and decreases the factor of safety. However, the shear strength of edifice rocks also exerts a significant control on stability, so both mechanical properties and pore‐fluid pressures are important for stability assessments.
Key Points
Permeability contrasts in stratovolcanoes can create perched water and locally elevated pore‐fluid pressures at shallow levels in the flanks
Partially saturated edifices containing high pore‐fluid pressures result in factors of safety up to 61% lower than those in dry volcanoes
Models that do not account for variable water saturation and permeability distributions overestimate slope stability and collapse volume
The decline of the eastern population of the migratory monarch has become a topic of great concern, but has been based entirely on patterns observed in overwinter colony sizes. Less attention has ...been paid to population trends during other phases of the migratory cycle. Here, we present an analysis of trends using three monitoring programs, one focused on overwinter colony size and two focused on summer breeding grounds. We discovered an alarming steepening in the decline of winter colony size since 2008. However, population indices from two independent summer monitoring programs were characterized by high year-to-year variability and no statistically detectable trends over time. Despite the mismatch in summer and winter patterns, there is still an association between the yearly fluctuations between these key periods, suggesting a link in population dynamics throughout the year. Further, a suggestion of a downturn near the end of the summer time-series should be carefully tracked into the future. We discuss two possible reasons for this disconnect: 1) higher levels of variance or possibly biased sampling could weaken any statistical signal, and 2) losses during fall migration could potentially contribute to overwinter declines.
This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. ...dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross‐tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.
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