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The purpose of this paper was to validate the Spanish version of the Perceived Locus of Causality Scale (PLOC; Goudas, Biddle, & Fox, 1994). To achieve this, two studies with samples of 1535 and 400 physical education students, of ages 12 to 17 years, were carried out. The psychometric properties of the PLOC were examined through the following analyses: confirmatory factor analysis, factor invariance, correlation among factors, reliability (Cronbach's alpha), temporal stability (test-retest), and criterion validity. The results partially supported the five-factor structure. This structure was invariant across the two study samples. Correlations among the subscales indicated a simplex pattern, supporting construct validity of the scale. Alpha values over .70 (except for introjected regulation) and high temporal stability (intra-class correlation coefficient = .83 to .90) over a four-week period were obtained. The mastery-approach goal positively predicted self-determined motivation, whereas the performance-avoidance goal predicted it negatively. Future studies should continue to analyze the psychometric properties of the PLOC, as the validation of an instrument should be an ongoing process. El objetivo de este trabajo fue validar la versión española de la Escala del Locus Percibido de Causalidad (PLOC) de Goudas, Biddle y Fox (1994). Para ello, se llevaron a cabo dos estudios con muestras de 1535 y 400 alumnos en clases de educación física, edades entre 12 y 17 años. Se analizaron las propiedades psicométricas de la PLOC por medio de análisis factoriales confirmatorios, análisis de la invarianza factorial, análisis de correlaciones entre factores, fiabilidad a través del alfa de Cronbach, estabilidad temporal test-retest y validez de criterio. Los resultados ofrecieron un apoyo parcial a la estructura de cinco factores. Esta estructura se mostró invariante entre las dos muestras de estudio. Las correlaciones entre las subescalas indicaron un modelo simplex que apoya la validez de constructo de la escala. Se obtuvieron valores alfa de Cronbach superiores a .70, salvo para la regulación introyectada, y altos niveles de estabilidad temporal (coeficiente de correlación intra-clase = .83 a .90) en un periodo de cuatros semanas. La meta de aproximación-maestría predijo positivamente la motivación autodeterminada, mientras que la meta de evitación-rendimiento lo hizo de forma negativa. Futuros trabajos deberán continuar analizando las propiedades psicométricas de la PLOC, puesto que la validación de un instrumento debe ser un proceso continuado.

The purpose of this investigation was to examine the relationships among perceived motivational climate, individuals' goal orientations, and dispositional flow, with attention to possible gender differences. A sample of 413 young athletes, ages 12 to 16 years, completed the Perceived Motivational Climate in Sport Questionnaire-2 (PMCSQ-2) and Perception of Success Questionnaire (POSQ), as well as the Dispositional Flow Scale. Task orientation was positively and significantly related to a perceived task- involving motivational climate and to the disposition to experience flow in the sport. Ego orientation was positively and significantly associated with a perceived ego-involving motivational climate and with dispositional flow. The perceptions of task-involving and ego-involving motivational climates were positively and significantly linked to general dispositional flow. Multiple regression analysis indicated that both task and ego goal orientations and perceived task- and ego-oriented climates predicted dispositional flow. Males displayed a stronger ego orientation, and were more likely to report that they participated in an ego-oriented climate, than did females. To the contrary, the females were more likely to perceive a task-oriented climate than did the males. No meaningful differences were found between males and females in general dispositional flow. El objetivo de esta investigación era examinar las relaciones entre el clima motivacional percibido, las orientaciones de meta y la disposición al “flow” de los individuos, atendiendo las posibles diferencias de género. Una muestra de 413 atletas jóvenes, de edades entre 12 y 16 años, completaron el Perceived Motivational Climate in Sport Questionnaire-2 (PMCSQ-2) y el Perception of Success Questionnaire (POSQ), además de la Dispositional Flow Scale. La orientación a la tarea tenía una relación positiva y significativa con el clima motivacional implicante a la tarea percibido y con la disposición a experimentar el “flow” en el deporte. La orientación al ego tenía una relación positiva y significativa con el clima motivacional implicante al ego percibido y con el flow disposicional. Las percepciones de climas motivacionales implicantes a la tarea y al ego tenían una relación positiva y significativa con el flow general disposicional. El análisis de regresión múltiple indicaba que tanto las orientaciones de meta a la tarea y al ego y los climas percibidos orientados a la tarea y al ego predecían el flow disposicional. Los varones mostraron una orientación al ego más fuerte y era más probable que dijeran que participaban en un clima orientado al ego que las mujeres. En contraste, era más probable que las mujeres percibieran un clima orientado a la tarea que los varones. No se encontraron diferencias significativas entre varones y mujeres en el flow disposicional general.

The reaction of one equivalent of 1,2,4,5-tetrakis(pyrazolyl-methyl)benzene ligand ( L ) with two equivalents of Cr(THF) 3 Cl 3 in tetrahydrofuran has produced a binuclear neutral complex of general formula [Cr 2 L(THF) 2 Cl 6 ] (1) . It was characterized by mass spectrometry, Fourier-transformed infrared, X-ray photoelectron spectroscopy, and magnetic susceptibility. Theoretical calculations supported the formation of binuclear complex (1) with each hexacoordinate metal center. This complex was active in ethylene polymerization employing methylaluminoxane as cocatalyst, with moderate activities (5.7–20.8 kg polymer/(mol precat.) (bar) (h)). The reaction parameters such as temperature, monomer pressure, and Al/Cr ratio were studied. An increase of reaction temperature produced a decreasing of catalytic activity. However, an increase in the monomer pressure did not produce a significant increase in catalytic activity. The Al/Cr ratios used to activate this complex are smaller than those reported for the tris(pyrazolyl)borate chromium complex. This system produced high-density polyethylenes with wide molecular weight, M w , distributions between 42,280 and 74,346 and polydispersity index from 2.3 to 6.6. Graphic abstract

The aim of this study was to examine the relationship between motivational characteristics and dispositional flow. In order to accomplish this goal, motivational profiles emerging from key constructs within Achievement Goal Theory and Self-Determination Theory were related to the dispositional flow measures. A sample of 413 young athletes (Age range 12 to 16 years) completed the PMCSQ-2, POSQ, SMS and DFS measures. Cluster analysis results revealed three profiles: a \"self-determined profile \"characterised by higher scores on the task-involving climate perception and on the task orientation; a \"non-self-determined profile\", characterised by higher scores on ego-involving climate perception and ego orientation; and a \"low self-determined and low non-self-determined profile \"which had the lowest dispositional flow. No meaningful differences were found between the \"self-determined profile \"and the \"non-self-determined profile \"in dispositional flow. The \"self-determined profile \"was more commonly associated with females, athletes practising individual sports and those training more than three days a week. The \"non-self-determined profile \"was more customary of males and athletes practising team sports as well as those training just two or three days a week. Key pointsThe \"self-determined profile \"was characterized by high task orientation, high task-involving climate perception and was more commonly associated with females, athletes practising individual sports and those training more than three days a week.The \"non-self-determined profile \"was characterized by high ego orientation, high ego-involving climate perception and was more customary of males and athletes practising team sports as well as those training two or three days a week.Both profiles revealed a moderate tendency toward dispositional flow, with no significant differences between the two profiles.The \"low self-determined and low non-self-determined profile \"had low scores on all of the variables in the study.

Our objective in this study was to test the new social-cognitive model of achievement motivation in a physical education setting. Research was conducted on a sample of 895 physical education students, ages 12 to 16 years. We measured perception of the motivational climate conveyed by the teacher, implicit beliefs of ability, perceived competence, 2 x 2 achievement goals and self-determined motivation. We carried out structural equation modeling to analyse the relationships among variables. Results showed that task climate positively predicted incremental belief, whereas ego climate positively predicted entity belief. Both climates positively predicted perceived competence. Incremental belief positively predicted mastery-approach goals, performance-approach goals and avoidance goals, whereas entity belief positively predicted performance-approach goals and avoidance goals. Perceived competence positively predicted mastery-approach and performance-approach goals. Mastery-approach goal positively predicted self-determined motivation, whereas performance-approach goal and avoidance goals negatively predicted self-determined motivation.

The purpose of this study was to analyze some factors that influence amotivation in physical education classes. A sample of 399 students, of ages 14 to 16 years, was used. They completed the Perceived Autonomy Support Scale in Exercise Settings (PASSES), the Social Goal Scale-Physical Education (SGS-PE), the <> factor of the Basic Psychological Needs in Exercise Scale (BPNES) adapted to physical education and the <> factor of the Perceived Locus of Causality Scale (PLOC). The psychometric properties of the PASSES were analyzed, as this scale had not been validated to the Spanish context. In this analysis, the scale showed appropriate validity and reliability. The results of the structural equation model indicated that social responsibility and social relationship goals positively predicted perception of relatedness, whereas the context of autonomy support did not significantly predict it. In turn, perception of relatedness negatively predicted amotivation. The findings are discussed with regard to enhancing students' positive motivation.

New imidazolium salts derived from the natural methylated xanthines theophylline, theobromine and caffeine, namely 1,3-dimethyl-9-benzylxanthinium bromide (tphBzBr, 1a ), 3,7-dimethyl-9-benzylxanthinium bromide (tbrBzBr, 2a ) and 1,3,7-trimethyl-9-benzylxanthinium bromide (caffBzBr, 3a ), are reported. Also, the disubstituted analog of 1a , 1,3-dimethyl-7,9-dibenzylxanthinium bromide (tphBz 2 Br, 1a ′) was identified and characterized by NMR. The coordination chemistry of ligands 1a – 3a toward palladium, and some theoretical aspects of the unmodified theophylline, theobromine and caffeine are studied. Our results prove that the theophylline derivative has the thermodynamic tendency to form N-bonded species, even when an equilibrium between the Pd–NHC and the “theophyllinate” was observed spectroscopically, due to the anisotropy of the NHC ligand. To confirm the N-coordination, the solid state structure of the new “theophyllinate” species PdBr 2 (tphBz-H) 2 ( 4 ), derived from 1a , was determined by X-ray diffraction. The analog with theobromine, ligand 2a , coordinates to palladium via N1, in an analogous manner to 1a , and a mixture of the cis/trans isomers of its palladium complex is obtained. On the other hand, since there is no possibility of N-coordination in 3a , this caffeine derivative forms a Pd-NHC compound after deprotonation with a strong base. Both the theoretical results and the experimental evidence are in accordance, in terms of the predicted coordination sites or possibility of modification of the selected methylated xanthines to obtain new ligands.

Livestock manure has a high ammonium content that can limit its direct application on soil as a fertiliser in nitrate-vulnerable zones. Treatment technologies that are able to extract ammonium from livestock manure allow it to be concentrated in small volumes, making it cheaper and easier to transport and use as fertiliser in crop areas where there is a deficit of nitrogen. This study proposed using low-temperature vacuum evaporation to treat pig slurry in order to obtain marketable products that can be used as fertilisers and help close the nitrogen cycle. Two different configurations and scales were used. The first was a seven-litre laboratory-scale evaporator complemented with a condenser, a condensate trapper, an acid trap and a vacuum pump operated at −90 kPa vacuum pressure and at three different temperatures: 50.1 ± 0.2 °C, 46.0 ± 0.1 °C and 45.3 ± 1.3 °C. The second, Ammoneva, is an on-farm pilot-scale evaporator (6.4 m3), capable of working in four-hour batches of 1 t of liquid fraction of pig slurry with an operating temperature of 40–45 °C and −80 kPa vacuum pressure. The laboratory-scale evaporator, which features several novel improvements focused on increasing ammonia recovery, showed a higher nitrogen removal efficiency from the liquid fraction of pig slurry than the on-farm pilot plant, achieving 84% at 50.1 °C operation, and recovering most of it in ammonia solution (up to 77% of the initial nitrogen), with 7% of the ammonia not recovered. The Ammoneva pilot plant achieved a treated liquid fraction with 41% of initial nitrogen on average, recovering 15% in the ammonia solution in the acid trap; so, the NH3 gas absorption step needs to be further optimised. However, due to the simplicity of the Ammoneva pilot plant, which is easily placed inside a 20-foot container, and the complete automation of the process, it is suitable as an on-farm treatment for decentralised pig slurry management. The implementation of the novel design developed at laboratory-scale could help further increase recovery efficiencies at the pilot-plant scale.