When do firms rely on their knowledge spillover recipients for guidance in exploring unfamiliar knowledge?     

Hongyan Yang  H. Kevin Steensma 《Research Policy》2014

Knowledge spillover occurs when recipient firms combine the knowledge of an originating firm with other knowledge. When recipient firms combine the originating firm's knowledge with knowledge that is unfamiliar to the originating firm, the recipient firms potentially provide insight to the originating firm on the viability of exploring such knowledge. By mimicking its recipient firms, the originating firm reduces the challenge and uncertainty of exploring unfamiliar knowledge domains. We examine the exploration activities of 87 telecommunications equipment manufacturers over a ten-year time period. We argue that those firms that operate in competitive and dynamic market environments promoting conservative risk-taking behavior will value such uncertainty reduction more highly and thus rely to a greater extent on their recipient firms for guidance on where to explore for new expertise. In contrast, firms in high-growth market environments are more likely to look beyond the activities of recipient firms when exploring new technological domains and rely less on mimicking their recipient firms.  相似文献   

Tilted post arrays for separating long DNA     

Joel D. P. Thomas  Kevin D. Dorfman 《Biomicrofluidics》2014,8(3)

Recent simulations by Chen and Dorfman [Electrophoresis 35, 405–411 (2014)] suggested that “tilting” the electric field with respect to the lattice vectors of a hexagonal post array would lead to a substantial improvement in electrophoretic DNA separations therein. We constructed such an array where the electric field is applied at an angle equidistant between the two lattice vectors. This tilted array leads to (i) baseline resolution of 20 kbp DNA and λ DNA (48.5 kbp) in a 4 mm channel and (ii) measurable separation resolutions for electric fields up to 50 V/cm, both of which are improvements over untilted post arrays of the same post density. The predicted time required to reach a resolution of unity is approximately 5 min, independent of electric field. The separations are more reproducible at higher fields.  相似文献   

The evidence for the impact of policy on physical activity outcomes within the school setting: A systematic review     

Catherine B. Woods  Kevin Volf  Liam Kelly  Blthín Casey  Peter Gelius  Sven Messing  Sarah Forberger  Jeroen Lakerveld  Joanna Zukowska  Enrique García Bengoechea  PEN consortium 《运动与健康科学(英文)》2021,10(3):263

BackgroundDespite the well-established health benefits of physical activity (PA) for young people (aged 4–19 years), most do not meet PA guidelines. Policies that support PA in schools may be promising, but their impact on PA behavior is poorly understood. The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.MethodsThis systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Six databases were searched using key concepts of policy, school, evaluation, and PA. Following title and abstract screening of 2323 studies, 25 progressed to data synthesis. Methodological quality was assessed using standardized tools, and the strength of the evidence of policy impact was described based on pre-determined codes: positive, negative, inconclusive, or untested statistically.ResultsEvidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting. These were whole school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks/recess, physical environment, shared use agreements, active school transport, and surveillance. The bulk of the evidence was significantly positive (54%), 27% was inconclusive, 9% was significantly negative, and 11% was untested (due to rounding, some numbers add to 99% or 101%). Frequency of evidence was highest in the primary setting (41%), 34% in the secondary setting, and 24% in primary/secondary combined school settings. By policy area, frequency of evidence was highest for sport/extracurricular PA (35%), 17% for physical education, and 12% for whole school PA policy, with evidence for shared use agreements between schools and local communities rarely reported (2%). Comparing relative strength of evidence, the evidence for shared use agreements, though sparse, was 100% positive, while 60% of the evidence for whole school PA policy, 59% of the evidence for sport/extracurricular PA, 57% of the evidence for physical education, 50% of the evidence for PA in classroom, and 50% of the evidence for active breaks/recess were positive.ConclusionThe current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a “one-size-fits-all” approach and emphasizes the need to examine policy implementation to maximize translation into practice. Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed.  相似文献   

Onset of channeling during DNA electrophoresis in a sparse ordered post array     

Jia Ou  Samuel J. Carpenter    Kevin D. Dorfman 《Biomicrofluidics》2010,4(1)

The “channeling hypothesis” of DNA electrophoresis in sparse, ordered arrays of posts predicts that the DNA will move through the array relatively unhindered if (i) the spacing between the posts is larger than the DNA coil and (ii) the electric field lines are straight. We tested this hypothesis by studying the electrophoretic separation of a small plasmid DNA (pUC19, 2686 base pairs) and a large, linear DNA (λ-DNA, 48 500 base pairs) in a hexagonal array of 1 μm diameter posts with a pitch of 7 μm. At low electric field strengths, these DNAs are separated due to the long-lived, rope-over-pulley collisions of λ-DNA with the posts. The resolution is lost as the electric field increases due to the onset of channeling by the λ-DNA. Using a diffusive model, we show that channeling arises at low electric fields due to the finite size of the array. This channeling is not intrinsic to the system and is attenuated by increasing the size of the array. Higher electric fields lead to intrinsic channeling, which is attributed to the disparate time scales for a rope-over-pulley collision and transverse diffusion between collisions. The onset of channeling is a gradual process, in agreement with extant Brownian dynamics simulation data. Even at weak electric fields, the electrophoretic mobility of λ-DNA in the array is considerably higher than would be expected if the DNA frequently collided with the posts.  相似文献   

‘Active Citizens’: the case of school governors     

Kevin J. Brehony 《International Studies in Sociology of Education》2013,23(2):199-217

ABSTRACT

This article reviews current and historical debates about active, participant citizens and related conceptions of citizenship. In particular it focusses on the prospects for the participation of citizens in the administration of public bodies. It discusses critically the notion of participative citizenship and active citizenship as articulated by Douglas Hurd (when Home Secretary) and also the version contained in the report of the Speaker's Commission on Citizenship. The article then draws upon research conducted for the Volunteer Centre, by the National Foundation for Educational Research and that by Brehony and Deem which is funded by an Economic and Social Research Council Grant (R000 23 1799), on voluntary activity and school governors, respectively. The applicability of the concept of active citizenship to the oversight of schools by school governing bodies is then considered alongside recent work in the United States. The article then considers the constraints upon active citizenship which prevent many governors from participating as much as the role demands and it ends with a reference to the tension between those who see governing bodies as an arena for democratic accountability and the active participation of citizens and those who view them principally as a means by which the local state is weakened and its functions increasingly transferred to the voluntary sector.  相似文献   

Effects of false-start disqualification rules on response-times of elite-standard sprinters     

Kevin C. Brosnan  Kevin Hayes  Andrew J. Harrison 《Journal of sports sciences》2017,35(10):929-935

The 100 ms ruling for false start disqualification at athletic competitions governed by the International Association of Athletics Federations has been in force since the early 1990s. Throughout this period, there have been marked changes to the rules that govern the disqualification of athletes from sprint events incorporating starts from blocks. This study analysed all available World and European Championship response-time (RT) data from 1999 to 2014 to examine effects of rule changes on competition RT at major championships. The exponentially modified Gaussian distribution was used to model RT and make comparisons relative to athletes’ sex, ruling periods and competition rounds. Revised RT thresholds of 115 ms and 119 ms were identified for men and women, respectively, indicating that the current 100 ms rule could result in some false starts not being detected in competitive athletics. The study proposes that when using existing International Association of Athletics Federations approved systems, the false start detection threshold should be increased and that men and women athletes should have different thresholds because of substantial evidence of a sex-based difference in RT in elite-standard athletes.  相似文献   

Teacher Acceptability of Functional Assessment-Derived Treatments     

Kevin M. Jones  Cheryl J. Lungaro 《Journal of educational and psychological consultation》2013,23(3-4):323-332

This study examines whether teachers find a treatment clearly linked to a functional assessment more acceptable than treatments based on arbitrarily selected reinforcers. We randomly assigned 111 elementary school teachers to 3 experimental conditions. In all conditions, a problem vignette was read that included the same functional assessment summary but varied according to whether the treatment recommendation was linked to the assessment results. A one-way analysis of variance revealed significantly higher pretreatment acceptability ratings and likelihood of use for the treatment linked to assessment. Implications of these results for school-based consultation are discussed.  相似文献   

Intellectual self-mutilation     

Kevin Robins  Frank Webster 《Higher Education Quarterly》1985,39(2):97-104

[The] business man is generous to a fault, but one thing he does demand of all teachers and lecturers and journalists: if we're going to pay them our good money, they‘ve got to help us by selling efficiency and whooping it up for rational prosperity? And when it comes to these blab-mouth, fault-finding, pessimistic, cynical University teachers, let me tell you that during this golden coming year it's just as much our duty to bring influence to have these cusses fired as it is to sell all the real estate and gather in all the good shekels we can. Sinclair Lewis. Babbitt.  相似文献   

"A favored child of the state": Federal Student Aid at Ohio Colleges and Universities, 1934–1943     

Kevin P. Bower 《History of education quarterly》2004,44(3):364-387

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Kinematics of the field hockey penalty corner push-in     

Kerr R  Ness K 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(1):47-61

The aims of the study were to determine those variables that significantly affect push-in execution and thereby formulate coaching recommendations specific to the push-in. Two 50 Hz video cameras recorded transverse and longitudinal views of push-in trials performed by eight experienced and nine inexperienced male push-in performers. Video footage was digitized for data analysis of ball speed, stance width, drag distance, drag time, drag speed, centre of massy displacement and segment and stick displacements and velocities. Experienced push-in performers demonstrated a significantly greater (p < 0.05) stance width, a significantly greater distance between the ball and the front foot at the start of the push-in and a significantly faster ball speed than inexperienced performers. In addition, the experienced performers showed a significant positive correlation between ball speed and playing experience and tended to adopt a combination of simultaneous and sequential segment rotation to achieve accuracy and fast ball speed. The study yielded the following coaching recommendations for enhanced push-in performance: maximize drag distance by maximizing front foot-ball distance at the start of the push-in; use a combination of simultaneous and sequential segment rotations to optimise both accuracy and ball speed and maximize drag speed.  相似文献