3,311 research outputs found
Effects of Corn and Selected Weed Species on Feeding Behavior of the Stalk Borer, \u3ci\u3ePapaipema Nebris\u3c/i\u3e (Lepidoptera: Noctuidae)
Experiments were conducted in an outdoor insectary to examine behavioral interactions between fifth instar stalk borers, Papaiperna nebris, and potential host plant species. Plants tested included 6- and 8-leaf stage corn, Zea mays, and ten weed species (six broadleaf and four grass) commonly associated with corn production in southern Wisconsin. Broadleaf plants found to be acceptable hosts included Ambrosia trifida, Arnaranthus retroflexus, Rumex crispus, and Chenopodium album; Asclepias syriaca and Abutilon theophrasti were not acceptable as host plants. Corn and the other grass species (Agropyron repens, Bromus inermis, Dactylis glomerata, and Setaria faberi) were found to be acceptable hosts. All acceptable plants also supported larval development to the pupal stage, though on 6-leaf stage corn and the small-stemmed grasses the majority of larvae dispersed before completing development. Larvae developing on corn, A. triftda, and A. retroflexus pupated within the plant stem, whereas larvae developing on the other plants pupated in the soil near the plant on which they fed. Stalk borer larvae required substantially less time to bore into corn stalks than into the stems of the broadleaf plants. In a limited preference experiment, corn was clearly preferred as a host plant over the three broadleaf and one small-stemmed grass species tested
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Teleconnection in the martian atmosphere during the 2001 planet-encircling dust storm
Introduction: In July 2001 (Martian year 25), Mars was enshrouded by a thick veil of dust which lasted for several months and obscured the observation of its surface to spacecraft cameras and ground-based telescopes. The emergence and rapid evolution (within a few days) of multiple, isolated, regional dust storms which eventually attained planetary scale extent were observed by NASA’s Mars Global Surveyor (MGS) spacecraft using high resolution camera images and the thermal profiles and dust opacity measurements pro-vided by the Thermal Emission Spectrometer (TES) [1, 2].
We have applied a technique used in Terrestrial meteorology (sequential data assimilation, [3]) to ob-tain a complete, four-dimensional evolution of all the atmospheric variables during the period of this planet-encircling dust storm, even those which were not di-rectly observed by the MGS satellite, such as surface pressure and winds. We assimilated TES nadir-pointing thermal profiles and total dust opacities in a global circulation model of the Martian atmosphere, developed jointly by the University of Oxford and the Open University in the United Kingdom, with the col-laboration of the Laboratoire de Météorologie Dyna-mique in Paris (UK-MGCM) [4, 5, 6]
Análisis de una propuesta de evaluación en relación con la estructura conceptual de la proporcionalidad
La presente propuesta es una aproximación reflexiva y critica de las prácticas evaluativas que se vienen desarrollando en la enseñanza básica y media en las instituciones de carácter privado de la ciudad de Cali, sustentada desde nuestra propia experiencia como docentes en ejercicio y estudiantes de último semestre en Licenciatura de Matemáticas y Física de la Universidad del Valle, y apoyada en el análisis de unas actividades piloto de intervención y evaluación matemática, en torno a diferentes nociones y conceptos relacionados con la estructura conceptual del tópico de proporción y proporcionalidad en los grados de séptimo de educación básica y décimo de educación media que se realizaron a fin de plantear una serie de interrogantes cruciales en torno a la evaluación, dado su carácter organizador, dinamizador y potencializador del currículo. Esta propuesta se apoyará en el marco metodológico de los organizadores del currículo, donde la evaluación es un eje fundamental en el análisis didáctico que permite la articulación y organización de un currículo significativo para los intereses de los educandos
The role of virtual reality in built environment education
This study builds upon previous research on the integration of Virtual Reality (VR) within the built environment curriculum and aims to investigate the role of VR and three-dimensional (3D) computer modelling on learning and teaching in a school of the built environment. In order to achieve this aim, a number of academic experiences were analysed to explore the applicability and viability of 3D computer modelling and VR into built environment subject areas. Although two-dimensional (2D) representations have been greatly accepted by built environment professions and education, 3D computer representations and VR applications, offering interactivity and immersiveness, are not yet widely accepted. The study attempts to understand the values and challenges of integrating visualisation technologies into built environment teaching and investigates tutors’ perceptions, opinions and concerns with respect to these technologies. The study reports on the integration process and considers how 3D computer modelling and VR technologies can combine with, and extend, the existing range of learning and teaching methods appropriate to different disciplines and programme areas
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Success rates of re-excision after positive margins for invasive lobular carcinoma of the breast.
Rates of positive margins after surgical resection of invasive lobular carcinoma (ILC) are high (ranging from 18 to 60%), yet the efficacy of re-excision lumpReceptor subtypeectomy for clearing positive margins is unknown. Concerns about the diffuse nature of ILC may drive increased rates of completion mastectomy to treat positive margins, thus lowering breast conservation rates. We therefore determined the success rate of re-excision lumpectomy in women with ILC and positive margins after surgical resection. We identified 314 cases of stage I-III ILC treated with breast conserving surgery (BCS) at the University of California, San Francisco. Surgical procedures, pathology reports, and outcomes were analyzed using univariate and multivariate statistics and Cox-proportional hazards models. We evaluated outcomes before and after the year 2014, when new margin management consensus guidelines were published. Positive initial margins occurred in 118 (37.6%) cases. Of these, 62 (52.5%) underwent re-excision lumpectomy, which cleared the margin in 74.2%. On multivariate analysis, node negativity was significantly associated with successful re-excision (odds ratio [OR] 3.99, 95% CI 1.15-13.81, p = 0.029). After 2014, we saw fewer initial positive margins (42.7% versus 25.5%, p = 0.009), second surgeries (54.6% versus 20.2%, p < 0.001), and completion mastectomies (27.7% versus 4.5%, p < 0.001). In this large cohort of women with ILC, re-excision lumpectomy was highly successful at clearing positive margins. Additionally, positive margins and completion mastectomy rates significantly decreased over time. These findings highlight improvements in management of ILC, and suggest that completion mastectomy may not be required for those with positive margins after initial BCS
Network theory approach for data evaluation in the dynamic force spectroscopy of biomolecular interactions
Investigations of molecular bonds between single molecules and molecular
complexes by the dynamic force spectroscopy are subject to large fluctuations
at nanoscale and possible other aspecific binding, which mask the experimental
output. Big efforts are devoted to develop methods for effective selection of
the relevant experimental data, before taking the quantitative analysis of bond
parameters. Here we present a methodology which is based on the application of
graph theory. The force-distance curves corresponding to repeated pulling
events are mapped onto their correlation network (mathematical graph). On these
graphs the groups of similar curves appear as topological modules, which are
identified using the spectral analysis of graphs. We demonstrate the approach
by analyzing a large ensemble of the force-distance curves measured on:
ssDNA-ssDNA, peptide-RNA (system from HIV1), and peptide-Au surface. Within our
data sets the methodology systematically separates subgroups of curves which
are related to different intermolecular interactions and to spatial
arrangements in which the molecules are brought together and/or pulling speeds.
This demonstrates the sensitivity of the method to the spatial degrees of
freedom, suggesting potential applications in the case of large molecular
complexes and situations with multiple binding sites
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