The strange case of reproducibility versus representativeness in contextual suggestion test collections     

Thaer Samar  Alejandro Bellogín  Arjen P. de Vries 《Information Retrieval》2016,19(3):230-255

The most common approach to measuring the effectiveness of Information Retrieval systems is by using test collections. The Contextual Suggestion (CS) TREC track provides an evaluation framework for systems that recommend items to users given their geographical context. The specific nature of this track allows the participating teams to identify candidate documents either from the Open Web or from the ClueWeb12 collection, a static version of the web. In the judging pool, the documents from the Open Web and ClueWeb12 collection are distinguished. Hence, each system submission should be based only on one resource, either Open Web (identified by URLs) or ClueWeb12 (identified by ids). To achieve reproducibility, ranking web pages from ClueWeb12 should be the preferred method for scientific evaluation of CS systems, but it has been found that the systems that build their suggestion algorithms on top of input taken from the Open Web achieve consistently a higher effectiveness. Because most of the systems take a rather similar approach to making CSs, this raises the question whether systems built by researchers on top of ClueWeb12 are still representative of those that would work directly on industry-strength web search engines. Do we need to sacrifice reproducibility for the sake of representativeness? We study the difference in effectiveness between Open Web systems and ClueWeb12 systems through analyzing the relevance assessments of documents identified from both the Open Web and ClueWeb12. Then, we identify documents that overlap between the relevance assessments of the Open Web and ClueWeb12, observing a dependency between relevance assessments and the source of the document being taken from the Open Web or from ClueWeb12. After that, we identify documents from the relevance assessments of the Open Web which exist in the ClueWeb12 collection but do not exist in the ClueWeb12 relevance assessments. We use these documents to expand the ClueWeb12 relevance assessments. Our main findings are twofold. First, our empirical analysis of the relevance assessments of 2  years of CS track shows that Open Web documents receive better ratings than ClueWeb12 documents, especially if we look at the documents in the overlap. Second, our approach for selecting candidate documents from ClueWeb12 collection based on information obtained from the Open Web makes an improvement step towards partially bridging the gap in effectiveness between Open Web and ClueWeb12 systems, while at the same time we achieve reproducible results on well-known representative sample of the web.  相似文献   

Influence of football match time–motion parameters on recovery time course of muscle damage and jump ability     

Moisés de Hoyo  Daniel Dylan Cohen  Borja Sañudo  Luis Carrasco  Alejandro Álvarez-Mesa  Juan José del Ojo 《Journal of sports sciences》2016,34(14):1363-1370

ABSTRACT

We analysed the time course of recovery of creatine kinase (CK) and countermovement jump (CMJ) parameters after a football match, and correlations between changes in these variables and match time–motion parameters (GPS-accelerometry) in 15 U-19 elite male players. Plasma CK and CMJ height (CMJ_H), average concentric force (CMJ_CON) and average eccentric force (CMJ_ECC) were assessed 2 h before and 30 min, 24 h and 48 h post-match. There were substantially higher CK levels 30 min, 24 h and 48 h (ES: 0.43, 0.62, 0.40, respectively), post-match. CMJ_ECC (ES: ?0.38), CMJ_H (ES: ?0.35) decreased 30 min post, CMJ_CON (ES: ?0.35), CMJ_ECC (ES: ?0.35) and CMJ_H (ES: ?1.35) decreased 24 h post, and CMJ_CON (ES: ?0.41) and CMJ_H (ES: ?0.53) decreased 48 h post. We found correlations between distance covered at velocities ≤21 km · h^?1 and changes in CK at 24 h (r = 0.56) and at 48 h (r = 0.54) and correlations between CK and distance covered >14 km · h^?1 (r = 0.50), accelerations (r = 0.48), and decelerations (r = 0.58) at 48 h. Changes in CMJ_CON 30 min and 24 h post (both r = ?0.68) correlated with impacts >7.1·G. Decelerations >2 m · s^?2 correlated with changes CMJ_CON (r = ?0.49) at 48 h and CMJ_ECC (r = ?0.47) at 30 min. Our results suggest that match GPS-accelerometry parameters may predict muscle damage and changes in components of neuromuscular performance immediately and 24–48 h post-match.  相似文献   

Impact of an incremental running test on jumping kinematics in endurance runners: can jumping kinematic explain the post-activation potentiation phenomenon?     

Felipe García-Pinillos  Alejandro Molina-Molina  Pedro Á. Latorre-Román 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(2):103-115

This study aimed to determine whether kinematic data during countermovement jump (CMJ) might explain post-activation potentiation (PAP) phenomenon after an exhausting running test. Thirty-three trained endurance runners performed the Léger Test; an incremental test which consists of continuous running between two lines 20 m apart. CMJ performance was determined before (pre-test) and immediately after the protocol (post-test). Sagittal plane, video of CMJs was recorded and kinematic data were obtained throughout 2-Dimensional analysis. In addition to the duration of eccentric and concentric phases of CMJ, hip, knee and ankle angles were measured at four key points during CMJ: the lowest position of the squat, take-off, landing, and at the lowest position after landing. Additionally, heart rate was monitored, and rate of perceived exertion was recorded at post-test. Analysis of variance revealed a significant improvement in CMJ (p = 0.002) at post-test. Cluster analysis grouped according to whether PAP was experienced (responders group: RG, n = 25) or not (non-responders group: NRG, n = 8) relative to CMJ change from rest to post-test. RG significantly improved (p < 0.001) the performance in CMJ, whereas NRG remained unchanged. Kinematic data did not show significant differences between RG and NRG. Thus, the data suggest that jumping kinematic does not provide the necessary information to explain PAP phenomenon after intensive running exercises in endurance athletes.  相似文献   

Visuospatial Orientation Learning through Virtual Reality for People with Severe Disability     

Alejandro de la Torre-Luque  Luis Valero-Aguayo  Ernesto J. de la Rubia-Cuestas 《International Journal of Disability, Development & Education》2017,64(4):420-435

This study aims to test how an intervention based on virtual reality (VR) may enhance visuospatial skills amongst people with disability. A quasi-experimental intra-group study was therefore conducted. Participants were 20 people with severe disability (65% males; 34.35 years, on average, and 84.95% of disability rate according to the Andalusian Government index). Intervention consisted of 15 sessions of active navigation using a VR building similar to the participants’ day rehabilitation centre with the task of locating different rooms and objects. The time spent and errors in route in the virtual and the real environments were measured before and after the intervention. Additionally, participants had to fill out a map location task. As a result, participants showed fewer errors and less time at post-intervention assessments even with non-trained stimuli (p < .05). These results demonstrate the usefulness of VR-based interventions with active navigation to accelerate orientation learning in real-life situations.  相似文献   

Using research in practice     

Bexon N  Brice A  Booth A 《Health information and libraries journal》2003,20(4):240-243

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Effect of age on 16.1-km time-trial performance     

Balmer J  Bird S  Davison R  Lucia A 《Journal of sports sciences》2008,26(2):197-206

In this study, we assessed the performance of trained senior (n = 6) and veteran (n = 6) cyclists (mean age 28 years, s = 3 and 57 years, s = 4 respectively). Each competitor completed two cycling tests, a ramped peak aerobic test and an indoor 16.1-km time-trial. The tests were performed using a Kingcycle ergometer with the cyclists riding their own bicycle fitted with an SRM powermeter. Power output, heart rate, and gas exchange variables were recorded continuously and blood lactate concentration [HLa] was assessed 3 min after the peak ramped test and at 2.5-min intervals during the time-trial. Peak values for power output (RMP(max)), heart rate (HR(peak)), oxygen uptake (VO2(peak)), and ventilation (V(Epeak)) attained during the ramped test were higher in the senior group (P < 0.05), whereas [HLa](peak), RER(peak), V(E): VO2(peak), and economy(peak) were similar between groups (P > 0.05). Time-trial values (mean for duration of race) for power output (W(TT)), heart rate (HR(TT)), VO2 (VO(2TT)), and V(E) (V(ETT)) were higher in the seniors (P < 0.05), but [HLa](TT), RER(TT), V(ETT): VO2(TT), and economy(TT) were similar between the groups (P > 0.05). Time-trial exercise intensity, expressed as %RMP(max), %HR(peak), % VO2(peak), and % V(Epeak), was similar (P > 0.05) for seniors and veterans (W(TT): 81%, s = 2 vs. 78%, s = 8; HR(TT): 96%, s = 4 vs. 94%, s = 4; VO2(TT): 92%, s = 4 vs. 95%, s = 10; V(ETT): 89%, s = 8 vs. 85%, s = 8, respectively). Overall, seniors attained higher absolute values for power output, heart rate, VO2, and V(E) but not blood lactate concentration, respiratory exchange ratio (RER), V(E): VO2, and economy. Veterans did not accommodate age-related declines in time trial performance by maintaining higher relative exercise intensity.  相似文献   

You Gotta Represent¡ Ethnic Identity Development among Hispanic Adolescents     

Patricia Alvarez McHatton  Elizabeth Shaunessy  Claire Hughes  Alejandro Brice  Mary Ann Ratliff 《Multicultural Perspectives》2013,15(3):12-20

Hispanic students' awareness of cultural, linguistic, and sociopolitical issues are influenced by their experiences in schools and affect their sense of identity. An examination of student discourse between bilingual gifted and bilingual general education students in an urban middle school is presented, with particular attention given to how participating bilingual students relate to each other, peers (in general and gifted education), teachers, administrators, families, and communities, and how they perceive themselves. A discussion of the core issues that emerged, including students' reawakening to their ethnic identity, differing rationales for using native language, and observed differences in self-perceptions between the gifted and general education bilingual Hispanic students is provided, along with results and implications for future research.  相似文献   

Column Editors     

Andrew Booth  Anne Brice 《Health information and libraries journal》2001,18(3):175-177

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Risks, rules, and roles     

Shirley Brice Heath 《Zeitschrift für Erziehungswissenschaft》2000,3(1):61-80

Summary Based on ten years of fieldwork with a focus on macro-micro linkages from organizational ethos and structure to language behavior and roleplaying, this report centers on institutional changes that affect cognitive, social, and linguistic development of youth. Argued here is the resilience of those young people who find their way to youth-based (as distinct from youth-serving) organizations during their out-of-school lives. These organizations provide an institutional force to fill the voids left by intergenerational communication and nurturance breakdowns and an absence of meaningful work for youth in community and family life. Part 1 gives an overview of areas of interaction, work, and support that institutions fail to give in post-industrial societies and sets up the framework to view the fact that some youth create an institutional force through youth-based organizations that take over key socialization roles. Here crossage peers become their own agents to create an ecology of learning significantly different from customary agents of transmissive socialization. Part 2 answers the questions of what happens in this ecology of learning, and how learning works in youth-based organizations that place high emphasis on the real work of production and performance. Within these organizations that offer a type of liminal zone between childhood and full entry into adult life, youth take risks, play roles, and set their own rules in order to achieve a group goal of excellence in performance. Part 3 looks at language use within these organizations and addresses the means by which youth-based organizations remain dynamic and responsive to the rapidly changing dimensions of youth needs. Part 4 sets out certain changes necessary in the thinking of adults about models of socialization and their role in helping to make possible learning ecologies young people will see as effective. Part 5 pulls together the macro and micro dimensions of the findings to highlight the importance of research on the ways that rules, roles, and risks play within the work of learning.

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Zusammenfassung Risiken, Regeln und Rollen. Jugendperspektiven zur Lernarbeit in der Gemeindeentwicklung Basierend auf zehn Jahren Feldforslchung mit dem Fokus auf den Makro-Mikro-Zusammenh?ngen zwischen organisationaler Struktur und dazugeh?rigem Ethos einerseits und Sprachverhalten und Rollenspiel andererseits konzentriert sich dieser Beitrag auf den institutionellen Wandel, der sich auf die kognitive, soziale und sprachliche Entwicklung der Jugend auswirkt. Auff?llig ist die Selbstbehauptungskraft derjenigen Jugendlichen, die in ihrer au?erschulischen Freizeit den Weg zu jugendzentrierten Einrichtungen finden. Diese Organisationen vermitteln eine institutionelle Macht, die die Leere der intergenerationellen Kommunikation, der Bildungsabbrüche und der fehlenden Aufgaben für Jugendliche im Familien- und Gemeindeleben füllt. Abschnitt 1 gibt zum einen einen überblick über Interaktionsbereiche, die Arbeit und Unterstützung, die Institutionen der postindustriellen Gesellschaft nicht geben, und zeigt dann auf, welche institutionelle Kraft manche Jugendliche durch Engagement in jugendzentrierten Initiativen entwickeln, denen Schlüsselfunktionen in ihrer Sozialisation zukommen. Hier werden altersgemischte Peergruppen ihre eigenen Interessenvertreter, um eigene Lernumgebungen zu schaffen, die sich signifikant von den herk?mmlichen, auf Stoffvermittlung bestehenden Ans?tzen unterscheiden. Teil 2 beantwortet die Fragen, was in diesen Lernumwelten geschieht und welch wichtigen Platz Lernen in diesen jugendzentrierten Einrichtungen mit ihrer deutlichen Betonung von ernsthafter produktorientierter Arbeit und Darstellung einnehmen. In diesen Projekten mit ihrem Angebot für den Zeitraum zwischen Kindheit und vollst?ndigem Eintritt in das Erwachsenenleben akzeptieren Jugendliche Risiken, spielen Rollen und setzen sich Regeln, um hervorragende Gruppenergebnisse, z. B. bei einer Theateraufführung, zu erreichen. Abschnitt 3 betrachtet die Sprache, die in diesen Organisationen benutzt wird, und benennt die Mittel, mit deren Hilfe jugendzentrierte Einrichtungen dynamisch bleiben und auf die raschen Wechsel der jugendlichen Bedürfnisse antworten. Teil 4 beschreibt einige notwendige ?nderungen im Denken der Erwachsenen hinsichtlich der Sozialisationsmodelle und beschreibt ihre Rolle für die effektive Gestaltung von Lernumgebungen für junge Menschen. Im fünften Abschnitt werden Forschungsergebnisse der Makro- und Mikroebene zusammengefasst, um die Wichtigkeit der Forschung zu unterstreichen, die darüber aufkl?rt, welche Rolle Regeln, Rollen und Risiken in der Lernarbeit spielen.

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Spanish football and social change: sociological investigations     

Alejandro Quiroga 《Soccer & Society》2017,18(1):160-162

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