884 research outputs found
Questions as a Generative Strategy for Knowledge Transfer and Problem Solving
Consistent with generative learning theory, Grabowski (1996) suggests the use of questions may serve as an effective generative strategy for learning. However, the learning effects of questions have produced conflicting results (Bulu & Pedersen, 2010; Chen & Bradshaw, 2007; Choi, Land, & Turgeon, 2005; Chou & Liang, 2009; Davis & Linn, 2000; Dornisch & Sperling, 2008; Ge & Land, 2003). Similarly, there are five basic challenges inherent in question research (Andre, 1979). These include lack of intentional and consistent question design, lack of detail making it difficult to replicate studies, lack of control groups against which to measure differences, aggregation of results only while omitting a question-by-question analysis, and results based upon the learners\u27 ability to recall information versus near and far transfer (Andre, 1979). Of importance for this study is the latter. Knowledge transfer is a major contributor to problem-solving (Jonassen, 2011b; Mayer & Wittrock, 1996). This study assessed the use of domain-specific, domain-general, and combined-domain-general specific question types when compared to a control group of no questions as a generative strategy promoting knowledge acquisition, retention, and transfer in support of solving well-structured and ill-structured problems while controlling for the methodological concerns of Andre (1979). The domain of the instruction was interpersonal communications and was delivered as a web-based course in two instructional units along with pretest and posttest assessment, unit assessments, and a role-play simulation using an automated agent to measure far transfer problem solving. Results from the study suggested no significant differences between treatment groups for knowledge acquisition, retention, or near problem-solving transfer. The data did suggest significant differences in far problem-solving transfer for the treatment group receiving domain-specific questions only. Further, measures of central tendency suggest domain-specific questions may produce slightly greater gains in performance over domain-general only and combined domain-specific/domain-general questions
Determining the prey consumption, preferences, and potential for dietary overlap between invasive European green crab and native graceful crab in the Salish Sea
The global success of the invasive European green crab (Carcinus maenas) is due, in part, to its broad diet, with over 140 different genera consumed worldwide. However, very little of this information comes directly from populations in the Salish Sea and it is unclear the degree to which green crab select prey vs consuming what is readily available. Additionally, almost nothing is known about the diet of graceful crab (Metacarcinus gracilis), a common, co-occurring native species which may compete with green crabs. Although studies have hypothesized that graceful crabs may specialize on soft-bodied prey, this study is the first to document the types of locally available prey consumed by both of these crab species, their prey preferences, and potential for competition. A range of common intertidal invertebrates were offered as prey, including small native crabs (Hemigrapsus spp. and Pagarus spp.), common bivalve species, snails, and isopods. Crabs were allowed to forage individually on each prey species with appropriate substrate at natural prey densities. As expected, green crabs were able to consume a wide variety of prey, with a preference for bivalves. Graceful crabs were also able to consume most prey species, including those with hard shells, although the probability of consumption increased with crab size. These results support the hypothesis that these two crab species may compete for shared prey resources and suggests that more work should be done to understand the potential impacts of invasive green crabs on a common, but under-studied, native crab in the Salish Sea
Chromospheric Activity of HAT-P-11: an Unusually Active Planet-Hosting K Star
Kepler photometry of the hot Neptune host star HAT-P-11 suggests that its
spot latitude distribution is comparable to the Sun's near solar maximum. We
search for evidence of an activity cycle in the CaII H & K chromospheric
emission -index with archival Keck/HIRES spectra and observations from the
echelle spectrograph on the ARC 3.5 m Telescope at APO. The chromospheric
emission of HAT-P-11 is consistent with a year activity cycle,
which plateaued near maximum during the Kepler mission. In the cycle that we
observed, the star seemed to spend more time near active maximum than minimum.
We compare the normalized chromospheric emission index of
HAT-P-11 with other stars. HAT-P-11 has unusually strong chromospheric emission
compared to planet-hosting stars of similar effective temperature and rotation
period, perhaps due to tides raised by its planet.Comment: 16 pages, 8 figures; accepted to the Astrophysical Journa
Attitudes of Paramedic Students towards Specific Medical Conditions: A Four-Year Study
Purpose: The purpose of this study was to determine the attitude of first year students entering a paramedic course over 4 consecutive yearly intakes toward patients with intellectual disability, substance abuse, attempted suicide, and acute mental illness. Method: The students’ attitude towards four medical conditions commonly encountered in the out-of-hospital setting was assessed using the Medical Condition Regard Scale (MCRS). The MCRS score ranges from 11 to 66. Results: 230 students in Victoria, Australia, participated in the study; 66% were female, and 76% of all students \u3c 21 years of age. Students showed the most negative attitudes towards substance abuse, mean 35(SD+6.6), and the most positive attitude toward intellectual disability, mean 38.2(SD+6.3). Students in 2008 cohort displayed significantly higher regard for all medical conditions (pConclusions: The study findings suggest that these students in Victoria, Australia, entering an undergraduate paramedic or paramedic/nursing course have a relatively poor attitude towards the four reviewed medical conditions, particularly substance abuse
Yield, composition, and nutritive value of whole-plant grain sorghum silage: effects of hybrid, maturity, and grain addition
Call number: LD2668 .T4 ASI 1989 K57Master of ScienceAnimal Sciences and Industr
The Jamming Donut: A Free-Space Gripper based on Granular Jamming
Fruit harvesting has recently experienced a shift towards soft grippers that
possess compliance, adaptability, and delicacy. In this context, pneumatic
grippers are popular, due to provision of high deformability and compliance,
however they typically possess limited grip strength. Jamming possesses strong
grip capability, however has limited deformability and often requires the
object to be pushed onto a surface to attain a grip. This paper describes a
hybrid gripper combining pneumatics (for deformation) and jamming (for grip
strength). Our gripper utilises a torus (donut) structure with two chambers
controlled by pneumatic and vacuum pressure respectively, to conform around a
target object. The gripper displays good adaptability, exploiting pneumatics to
mould to the shape of the target object where jamming can be successfully
harnessed to grip. The main contribution of the paper is design, fabrication,
and characterisation of the first hybrid gripper that can use granular jamming
in free space, achieving significantly larger retention forces compared to pure
pneumatics. We test our gripper on a range of different sizes and shapes, as
well as picking a broad range of real fruit
Active Vibration Fluidization for Granular Jamming Grippers
Granular jamming has recently become popular in soft robotics with widespread
applications including industrial gripping, surgical robotics and haptics.
Previous work has investigated the use of various techniques that exploit the
nature of granular physics to improve jamming performance, however this is
generally underrepresented in the literature compared to its potential impact.
We present the first research that exploits vibration-based fluidisation
actively (e.g., during a grip) to elicit bespoke performance from granular
jamming grippers. We augment a conventional universal gripper with a
computer-controllled audio exciter, which is attached to the gripper via a 3D
printed mount, and build an automated test rig to allow large-scale data
collection to explore the effects of active vibration. We show that vibration
in soft jamming grippers can improve holding strength. In a series of studies,
we show that frequency and amplitude of the waveforms are key determinants to
performance, and that jamming performance is also dependent on temporal
properties of the induced waveform. We hope to encourage further study focused
on active vibrational control of jamming in soft robotics to improve
performance and increase diversity of potential applications.Comment: arXiv admin note: substantial text overlap with arXiv:2109.1049
State Power and Economic Inefficiency : Explaining Political Failture in Africa
SUMMARY The problem of agricultural crisis in Africa has forced a review of the highly centralised and bureaucratised structures used to provide services to farmers since independence, and has resulted in a return to favour of decentralised market mechanisms. This article traces the historical evolution of the present system in the colonial period, and sets out the theoretical and political assumptions which lay behind its retention in the post?colonial period. It then attempts to account for current failures by examining the theoretical inconsistencies and actual conflicts of interest involved in the attempt to use these structures in the political, economic and social conditions prevailing in post?colonial Africa. It concludes by recommending a more flexible approach based upon the use of decentralised private and cooperative structures directly accountable to the farmers who use them. SOMMAIRE Le problème de la crise agricole en Afrique a forcé une révision des structures bureaucratìques et hautement centralisées, utilisées pour procurer des services aux fermiers depuis l'indépendance, ceci a eu pour résultat de plaider en faveur des mécanismes de marché décentralisées. Cet article trace révolution historique du système actuel dans la période coloniale, et présente les assomptions qui sont derrière son maintien dans la période post?coloniale. On tente ensuite d'expliquer les échecs récents en analysant les contradictions théoriques et les conflits d'intérêt actuels impliqués dans les tentatives d'utiliser ces structures sous des conditions politiques, économiques et sociales prévalant dans l'Afrique post?coloniale. L'article conclut en recommandant une approche plus flexible, basée sur l'utilisation de structures privées décentralisées et des structures coopératives imputables aux fermiers utilisateurs. RESUMEN El problema de la crisis agrícola en Africa ha forzado a una revisión de las estructuras altamente centralizadas y burocráticas utilizadas para proporcionar servicios a los agricultores, resultando en un retorno en favor de los mecanismos descentralizados del mercado. Este artículo describe la evolución histórica del sistema actual en el periodo colonial y establece las hipótesis teóricas y políticas que yacen por detrás de su persistencia en el periodo post?colonial. A continuación intenta explicar los fracasos actuales mediante el examen de las incoherencias teóricas y los conflictos de intereses involucrados en el propósito de utilizar estas estructuras en las condiciones políticas, sociales y económicas prevalecientes en Africa post?colonial. Concluye recomendando un enfoque más flexible basado en el uso de estructuras descentralizadas, tanto privadas como cooperativas, directamente responsables ante los granjeros que las utilizan
Trace Fossils from the Shawangunk Formation in the Hudson Valley Indicate an Estuarine Depositional Environment
The Middle Silurian Shawangunk Formation crops out in the lower Hudson Valley and extends toward the southwest into New Jersey and Pennsylvania. It reaches a maximum thickness around Guymard (1,400 ft.; 400m) and gradually thins toward the northeast, pinching out near Binnewater, New York. The formation consists of gray conglomerate, quartz arenite, and minor shale. Worm burrows, Arthrophycus, Skolithos, Planolites?, and a bilobed resting trace have been found at different stratigraphic horizons in the Shawangunk Formation. All traces are associated with a finer, sandy matrix and/or hematite-rich interval rather than a coarse, pebbly quartz sandstone lithology dominant in the bulk of the unit, indicating a marine influence as well an environment with less energy than the braided stream environment inferred for most of the formation. Rivers and streams moving away from the eastern Taconic Mountains flowed into a westerly situated shallow marine basin. Eurypterids have previously been found on approximately the same stratigraphic levels as the traces and may be useful for constraining the depositional environment of these beds. Silurian eurypterids, now largely considered euryhaline, suggest that the environment of deposition was a marine-influenced estuary based on recent work documenting autochthonous assemblages of similar taxa in marginal marine settings. Association of eurypterids with Arthrophycus-dominated ichnofacies has been noted elsewhere in the Lower Silurian Tuscarora Formation in central Pennsylvania, suggesting a recurrent nearshore benthic assemblage
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