Functioning of plant-aphid-natural enemy interactions may be associated with the structure and composition of withinfield vegetation, neighborhood fields and field borders, and the regional plant community of cropped and noncropped areas. Farmand region-scale vegetation in the wheat-growing area of the North American Great Plains was hypothesized to effect the abundance of two hymenopteran parasitoids, that differ in physiological and behavioral attributes, of the key pest aphid of wheat, Diuraphis noxia (Mordvilko). The parasitoids had greater sensitivity to farm-scale vegetation (wheat strip rotation with or without spring-sown sunflower) than region-scale vegetation (degree of diversification with other crops and wheat fields converted to conservation grasslands). A two-way factorial design of scale (farm- and region-scale) revealed that parasitoid abundance in grass-dominant (homogeneous) areas especially benefited from adding sunflower to the wheat-fallow strip crop rotation. Considerable sensitivity of the analysis was added when adjusting for seasonality of vegetation, revealing that the region-scale effects were most prominent late season. From a management viewpoint, adding sunflower into the wheat production system, especially in relatively homogeneous vegetation regions, tends to promote local parasitoid populations during the summer when spring-sown plants are maturing and wheat is not in cultivation. Contrasting results for A. albipodus and L. testaceipes were consistent with expectations based on behavioral and physiological attributes of the two aphid parasitoid families they represent. Still, the general management interpretation seems robust for the two parasitoids and has relevance to both farm- and region-scale management schemes that are occurring in the wheat production zone of North American Great Plains.
Předmětem studie byla validizace české lokalizace Škály potřeby poznávání (Need for Cognition Scale, Cacioppo, Petty, 1982; Cacioppo, Petty, Kao, 1984). U souboru 679 osob byla provedena analýza faktorové a konstruktové validity metody vůči potřebě kognitivního uzavření a pravicovému autoritářství. Výsledkem je zjištění o možné dvoudimenzionální substruktuře metody v českém jazyce, s vysokou korelací pozitivního a negativního faktoru. Analýza konstruktové validity potvrdila mírnou až střední negativní souvislost potřeby poznávání s potřebou kognitivního uzavření a pravicovým autoritářstvím obdobně jako v dosavadních zahraničních studiích. Metoda NFCS je připravena pro použití v českém jazyce., Need for cognition refers to tendency to engage in and enjoy effortful cognitive activities. As conceptualized by Cacioppo and Petty (1982) need for cognition is a cognitive disposition, relatively stable in time and only slightly related to intellectual capacity and performance in terms of IQ. Need for Cognition Scale (NFCS) by Cacioppo and Petty is considered the most prevalent self-report method for assessing need for cognition. Validity study of short Czech version of the questionnaire was performed on a sample of 679 participants (62% men, age 16-43, Me=23). Results show good factor validity and high internal consistency - a two-factor congeneric model (factors based on item wording) showed the best fit among all four tested models and is in accordance with recent research. Construct validity was assessed using need for cognitive closure and right-wing authoritarianism questionnaires; in accordance with theoretical assumptions, NFCS correlates negatively with both measures. The specificity of the sample might pose some limitations, however, the translation can be considered validated for research purposes., and Jan Širůček, Adam Ťápal, Pavla Linhartová.
Objectives. The aim of this study was to create a Czech translation of the Perceived Stress Scale (PSS), to assess its psychometric properties on a representative sample of the Czech general adult population, and to compare the original 14-item version (PSS-14) with the shortened 10-item (PSS-10) and four-item (PSS-4) versions. Sample and setting. Two pilot studies were conducted to create the final Czech translation of the scale (n = 365 and n = 420). The final version of the Czech PSS was administered to a sample of the Czech general adult population (n = 1725 of whom 981 were women, M = 44.32,SD = 12.8). The Beck Depression Inventory (BDI-II) or the State-Trait Anxiety Inventory (STAI) were administered alongside the PSS to a part of the sample. A retest measurement after 14 days was conducted (n = 159). Statistical analysis. Using the confirmatory factor analysis, the one-factor, two-factor and bifactor models were compared. The internal consistency, stability in time, and convergent validity of the scale, as well as the known-group differences were assessed. The three versions of the PSS were compared. Results. The confirmatory factor analysis sup-ported the bifactor model of the PSS-14 and PSS-10, and the two-factor model of the PSS-4. All versions of the scale showed good internal consistency and stability in time. There was a moderate to strong positive correlation between the PSS and the BDI-II and STAI. Differences based on age, sex, education level, and situ-ational factors were found. Overall, the PSS-10 showed the best psychometric properties of all three versions of the scale. Study limitation. The sample consisted mostly of highly educated respondents. and Cíle. Cílem předkládané studie bylo vytvořit český překlad Škály vnímaného stresu (PSS), ověřit jeho psychometrické vlastnosti na repre-zentativním vzorku běžné české dospělé po-pulace, a porovnat psychometrické vlastnosti původní čtrnáctipoložkové škály (PSS-14) se zkrácenou desetipoložkovou (PSS-10) a čtyřpo-ložkovou (PSS-4) verzí. Výzkumný soubor a metody získávání dat. Při tvorbě českého překladu škály byly provedeny dvě pilotní studie (n = 365 a n = 420). Finální překlad škály byl administrován vzorku běž-né české populace (n = 1725, z toho 981 žen, M = 44,32, SD = 12,8). Části vzorku byla také administrována Beckova škála deprese (BDI-II) nebo Dotazník na měření úzkosti a úzkostlivosti (STAI). Po 14 dnech proběhl retest, kterého se zúčastnilo 159 respondentů. Analýza dat. Pomocí konfirmační faktorové analýzy autoři porovnali jednofaktorový, dvou-faktorový a bifaktorový model škály. Ověřili vnitřní konzistenci škály, její stabilitu v čase, konvergentní validitu a rozdíly mezi známými skupinami. Porovnali vlastnosti jednotlivých forem PSS. Výsledky. Konfirmační faktorová analýza pod-pořila bifaktorový model PSS-14 i PSS-10 a dvoufaktorový model PSS-4. Všechny tři formy škály dosahovaly dobré hodnoty vnitřní konzis-tence i stability v čase. Korelace PSS s BDI-II a STAI ukázaly středně silný až silný pozitiv-ní vztah. Byly nalezeny rozdíly v závislosti na věku, pohlaví, vzdělání a řadě situačních fakto-rů. Nejlepších psychometrických vlastností do-sahovala desetipoložková verze škály. Limity studie. Ve zkoumaném vzorku dominují respondenti s vysokoškolským vzděláním.