Influence of regression model and incremental test protocol on the relationship between lactate threshold using the maximal-deviation method and performance in female runners

This study examined the influence of the regression model and initial intensity of an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and the endurance performance. Sixteen non-competitive, recreational female runners performed a discontinuous incremental treadmill test. The initial speed was set at 7 km · h?1, and increased every 3 min by 1 km · h?1 with a 30-s rest between the stages used for earlobe capillary blood sample collection. Lactate-speed data were fitted by an exponential-plus-constant and a third-order polynomial equation. The lactate threshold was determined for both regression equations, using all the coordinates, excluding the first and excluding the first and second initial points. Mean speed of a 10-km road race was the performance index (3.04 ± 0.22 m · s?1). The exponentially-derived lactate threshold had a higher correlation (0.98 ≤ r ≤ 0.99) and smaller standard error of estimate (SEE) (0.04 ≤ SEE ≤ 0.05 m · s?1) with performance than the polynomially-derived equivalent (0.83 ≤ r ≤ 0.89; 0.10 ≤ SEE ≤ 0.13 m · s?1). The exponential lactate threshold was greater than the polynomial equivalent (P < 0.05). The results suggest that the exponential lactate threshold is a valid performance index that is independent of the initial intensity of the incremental test and better than the polynomial equivalent.     

Testing Inequality Constrained Hypotheses in SEM Models

Researchers often have expectations that can be expressed in the form of inequality constraints among the parameters of a structural equation model. It is currently not possible to test these so-called informative hypotheses in structural equation modeling software. We offer a solution to this problem using Mplus. The hypotheses are evaluated using plug-in p values with a calibrated alpha level. The method is introduced and its utility is illustrated by means of an example.     

Non-invasive methods for characterisation of printed cultural heritage

The quality of a book reprint depends on several factors, e.g. paper, typesetting, reproduction of illustrations, printing and bookbinding. The quality of the 1958 and 1988 reprints of the fairytale edition from 1944 designed by the Slovenian architect Jo?e Ple?nik was studied using standard and other non-invasive testing methods, e.g. microscopic and spectroscopic techniques, sonic velocity, Young's modulus of elasticity, surface topography and image analysis. The chemical, physical and colorimetric properties of papers and typographic tonal density were analysed. The results showed that the reprints do not correspond to the originals. Some of the differences in the reprints, if compared with the original (e.g. typographic tonal density), could have been easily avoided, while others (e.g. structural and optical properties of paper) remain unavoidable, mainly due to the influence of internal and external factors on the ageing. The ageing process influences paper properties, since optical properties deteriorate in time. It has been concluded that a precise and systematic study of the properties of an old book should be performed before the preparation of a reprint. The results of the research have shown that the applied methods are useful and satisfactory for the characterisation of the paper properties and typography, and can be of use at the analysis of printing ink and illustration reproduction.     

Key block theory application for rock slope stability analysis in the foundations of medieval castles in Slovakia

This research investigates the stability of rock slopes in the foundations of selected medieval castles in Slovakia. In the first phase, static analysis of the 45 selected medieval castle rock slopes was performed, where more than 12,000 potentially unstable blocks were analyzed and the factor of safety in static condition was calculated using the key block theory implemented in the Kbslope module of PTworkshop software. Based on results of the static stability analysis, a pseudo-static analysis was performed adopting the seismic acceleration in accordance with Slovak Technical Standards – Seismic actions on structures. This was implemented by calculating the vectors of horizontal force acting upon shear failure in the direction of the slope face with a zero vertical component. When non-finite and tapered blocks were ignored, the results proved that 14% of the 12,217 blocks investigated under static conditions could be considered unstable. This number increased to 23% under pseudo-static conditions, when seismic acceleration was implemented in the stability calculations. A detailed stability assessment of the Gymes Castle located in western Slovakia was carried out with delineation of blocks prone to rock sliding and proper stabilization methods, based on joint sets orientation measurements performed on the 3D point cloud generated by laser scanner.     

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.     

A mentor’s aid in developing the competences of teacher trainees

The induction period is a very important time in the career of a teacher and has a long‐term influence on the teacher’s professional development, efficacy, job satisfaction and the length of his/her career. One of the key roles in this period is played by the trainee’s mentor. This paper presents the results of the extensive project ‘Partnership of Faculties and Schools’, carried out at the Pedagogical Faculty, University of Ljubljana, with the financial support of the European Social Fund and the Slovenian Ministry of Education, Science and Sport. We studied an induction project involving 361 teacher trainees and 331 mentors. The study reveals the trainees’ expectations towards their mentors and the mentors’ and trainees’ evaluations of how the mentor aids a teacher trainee in developing their competences.     

Validity of Holland’s theory in adolescence: evidence from a Slovak sample

The underlying calculus assumption of Holland’s theory was tested in two samples of primary school students (N₁ = 400 and N₂ = 250) with an average age of 13.86 and 14.14 years, respectively. Both exploratory and confirmatory multidimensional scaling and Hubert and Arabie’s randomization test of hypothesized order relations were calculated. The circular spatial arrangement of RIASEC types was not confirmed in either of the two samples. The study discusses possible causes of the inappropriateness of using Holland’s model in an adolescent sample.

     

Social inequity and educational expansion in Slovenia

The study examines the relationship between social inequalities (stratificational, gender and other disparities) and schooling, including academic attainment, longitudinally, in Slovenia. The issue is indicated most clearly at the tertiary education level. The basic finding is the parallel between educational expansion and the diminution of social inequalities as measured by standard parameters. This was particularly evident in the 1990s. Inequalities are measured in terms of gender, parental education and occupation. The impact of parental education proves to be an indicative, observable and longitudinally comparative measure. Parental occupational status is also clearly linked to their children’s scholastic attainment, although there are difficulties in the formation of occupational strata. Further considered is the impact of school reforms over a lengthier period of time; there was not, however, any detectable impact. School and welfare policies, even financing, have little significance. There are clear indications that social disparities at school are continually regenerated, despite the decline established by standard measures. New forms of social disparities appear, through which the privileged ensure the continuation of privilege.