Assessing the nature of psychological contracts: conceptualization and measurement.

The purpose of this study is to clarify a feature-oriented assessment of psychological contracts, an underdeveloped approach to psychological contracts. From a theoretical perspective, the study aims to conceptualize the nature or different dimensions of a psychological contract drawing upon theoretical frameworks and cross-national research. Reviewing the 13 nation-studies of psychological contracts organized by Rousseau and Schalk (2000), we find support for the relevance of four theoretical dimensions: time frame, tangibility, scope and stability, as well as indications for two additional dimensions: power distance and individualization. From an empirical perspective, the 6 conceptualized dimensions are being operationalized in terms of employees' expected entitlements as well as their expected obligations and tested in a large, representative sample of 1,106 employees across industries, organizations and legal contracts. The analyses resulted in 12 scales and indicated that the expected entitlements and obligations of scope, stability, power distance and individualization do not highly correlate with each other while high correlations between entitlements and obligations of time frame and tangibility exist.Measurement;

Het concept psychologisch contract: het gevoerde debat.

In deze paper wordt het debat dat er rond de betekenis van het concept psychologisch contract wordt gevoerd, in kaart gebracht. We gaan van start met een 'historisch' overzicht van de definities van psychologisch contract. Vervolgens bespreken we een aantal punten van eensgezindheid en een aantal belangrijke discussiepunten die naar voor komen in het debat rond het concept psychologisch contract. In een vierde paragraaf brengen we verdere verduidelijking aan in het concept psychologisch contract door het te onderscheiden van een aantal verwante concepten. Op basis van de verschillende discussies komen we in de laatste paragraaf tot een eigen afbakening van het concept.

Multiple types of psychological contracts : a six-cluster solution.

The purpose of this study is to empirically examine the existence of particular types of psychological contracts. We take a feature-oriented approach towards psychological contracts, which allows more generalizability across settings than content-oriented assessments. In defining the types of psychological contracts, we rely on 10 dimensions that indicate the employees' expected entitlements as well as their expected obligations towards their employer. We assess the existence of types of psychological contracts based upon an economy-wide, representative sample. The analysis indicates the existence of six types of psychological contracts, all having different patterns of mutual expectations: an instrumental psychological contract, a weak psychological contract, a loyal psychological contract, an unattached psychological contract, an investing psychological contract and a strong psychological contract. Based on the profiles of the six types and its number of respondents, we conclude that the so-called transformation from traditional employment relationships towards 'new deals' is restricted to a very small group of young and highly educated professionals and managers.Employment; Expected; Managers; Studies;

Observación confirmada de Oxalis dillenii en España

We confirm the presence of Oxalis dillenii Jacq. in the Catalonian province Lleida (Catalonia, Spain). Identification was confirmed morphologically and through DNA barcode sequencing. A map of the distribution of O. dillenii is supplied, as are notes on its identification.Confirmamos la presencia de Oxalis dillenii Jacq. en la provincia de Lérida (Cataluña, España). La identidad de la especie fue confirmada tanto por sus características morfológicas como a través de la secuenciación del código de barras del ADN. Se proporciona un mapa de distribución de O. dillenii, así como notas sobre su identificación

Les activitats humanes estan induint un desajust entre el Carboni, el Nitrogen i el Fòsfor

Les activitats humanes augmenten contínuament les emissions de carboni (C) i nitrogen (N) al medi, tot incrementant així la desproporció entre aquests dos bioelements i el fòsfor (P) a la biosfera. Investigadors de la unitat d'Ecologia Global CREAF-CSIC-UAB han realitzat un estudi per estimar els nivells de la relació nitrogen:fòsfor (N:P) passats, presents i futurs de les emissions de l'espècie humana a la biosfera, per posteriorment comparar aquestes ràtios amb les ràtios dels organismes vius dels ecosistemes terrestres i aquàtics. De l'anàlisi de les dades es dedueix un progressiu rol limitant del P a molts ecosistemes i de manera general a tota la biosfera, la qual cosa disminueix la capacitat del planeta de fixar el C atmosfèric emès per la nostra espècie i afecta la proporció N:P dels ecosistemes, determinant de la seva estructura i funcionament.Las actividades humanas aumentan continuamente las emisiones de carbono (C) y nitrógeno (N) en el medio, incrementando así la desproporción entre estos dos bioelementos y el fósforo (P) a la biosfera. Investigadores de la unidad de Ecología Global CREAF-CSIC- UAB han realizado un estudio para estimar los niveles de la relación nitrógeno: fósforo (N: P) pasados, presentes y futuros de las emisiones de la especie humana en la biosfera, para posteriormente comparar estas ratios con las de los organismos vivos de los ecosistemas terrestres y acuáticos. Del análisis de los datos se deduce un progresivo rol limitante del P en muchos ecosistemas y de manera general en toda la biosfera, lo que disminuye la capacidad del planeta de fijar el C atmosférico emitido por nuestra especie y afecta a la proporción N : P de los ecosistemas, determinante en su estructura y funcionamiento.Human activities by increasing carbon (C) and nitrogen (N) emissions are enhancing the imbalance of C and N with phosphorous (P) in Earth's systems. Researches of the Global Ecology Unit CREAF-CSIC-UAB have conducted an study to estimate the past, present and future N:P ratios of the emissions from human activities and compared them with the N:P ratios of the main terrestrial ecosystems. The analysis of the data confers to P an increasing limiting role in the Earth's life system by affecting carbon-sequestration capacity potential and by affecting the structure, function and evolution of the Earth's ecosystems through the increasing N:P ratios

Needle age-related and seasonal photosynthetic capacity variation is negligible for modelling yearly gas exchange of a sparse temperate Scots pine forest

In this study, we quantified the predictive accuracy loss involved with omitting photosynthetic capacity variation for a Scots pine (<i>Pinus sylvestris</i> L.) stand in Flanders, Belgium. Over the course of one phenological year, we measured the maximum carboxylation capacity at 25 &deg;C (<i>V</i>_m25), the maximum electron transport capacity at 25 &deg;C (<i>J</i>_m25), and the leaf area index (LAI) of different-aged needle cohorts in the upper and lower canopy. We used these measurements as input for a process-based multi-layer canopy model with the objective to quantify the difference in yearly gross ecosystem productivity (GEP) and canopy transpiration (<i>E</i>_can) simulated under scenarios in which the observed needle age-related and/or seasonal variation of <i>V</i>_m25 and <i>J</i>_m25 was omitted. We compared simulated GEP with estimations obtained from eddy covariance measurements. Additionally, we measured summer needle N content to investigate the relationship between photosynthetic capacity parameters and needle N content along different needle ages. <br><br> Results show that <i>V</i>_m25 and <i>J</i>_m25 were, respectively, 27% and 13% higher in current-year than in one-year old needles. A significant seasonality effect was found on <i>V</i>_m25, but not on <i>J</i>_m25. Summer needle N content was considerably lower in current-year than in one-year-old needles. As a result, the correlations between <i>V</i>_m25 and needle N content and <i>J</i>_m25 and needle N content were negative and non-significant, respectively. Some explanations for these unexpected correlations were brought forward. Yearly GEP was overestimated by the canopy model by &plusmn;15% under all scenarios. The inclusion and omission of the observed needle age-related <i>V</i>_m25 and <i>J</i>_m25 variation in the model simulations led to statistically significant but ecologically irrelevant differences in simulated yearly GEP and <i>E</i>_can. Omitting seasonal variation did not yield significant simulation differences. Our results indicate that intensive photosynthetic capacity measurements over the full growing season and separate simulation of needle age classes were no prerequisites for accurate simulations of yearly canopy gas exchange. This is true, at least, for the studied stand, which has a very sparse canopy and is exposed to high N deposition and, hence, is not fully representative for temperate Scots pine stands. Nevertheless, we believe well-parameterized process-based canopy models – as applied in this study – are a useful tool to quantify losses of predictive accuracy involved with canopy simplification in modelling

A new spatially and temporally variable sigma parameter in degree-day melt modelling of the Greenland Ice Sheet 1870–2013

The degree-day based method of calculating ice-/snow-melt across the Greenland Ice Sheet (GrIS) commonly includes the temperature parameter sigma (σ) accounting for temperature variability on short (sub-monthly down to hourly) timescales, in order to capture melt in months where the mean temperature is below 0 °C. Sigma is typically assumed to be constant in space and time, with values ranging from ~ 2.5 to 5.5 °C. It is unclear in many cases how these values were derived and little sensitivity analysis or validation has been conducted. Here we determine spatially and temporally varying monthly values of σ for the unique, extended 1870–2013 timescale based on downscaled, corrected European Centre for Medium-Range Weather Forecasts (ECMWF) Interim (ERA-I) and Twentieth Century Reanalysis (20CR) meteorological reanalysis 2 m air temperatures on a 5 km × 5 km polar stereographic grid for the GrIS. The resulting monthly σ values reveal a distinct seasonal cycle. The mean summer σ value for the study period is ~ 3.2 °C, around 1 °C lower than the value of 4.2 °C commonly used in the literature. Sigma values for individual summers range from 1.7 to 5.9 °C. Since the summer months dominate the melt calculation, use of the new variable σ parameter would lead to a smaller melt area and a more positive surface mass balance for the GrIS. Validation of our new variable σ dataset shows good agreement with standard deviations calculated from automatic weather station observations across the ice sheet. Trend analysis shows large areas of the ice sheet exhibit statistically significant increasing temperature variability from 1870–2013 in all seasons, with notable exceptions around Summit in spring, and Summit and South Dome in winter. More recently, since 1990, σ has been decreasing, significantly so in the north-west during July. These interannual σ trends reflect climate change and variability processes operating across the ice sheet, several mechanisms of which are briefly discussed

Identical Bands in Superdeformed Nuclei: A Relativistic Description

Relativistic Mean Field Theory in the rotating frame is used to describe superdeformed nuclei. Nuclear currents and the resulting spatial components of the vector meson fields are fully taken into account. Identical bands in neighboring Rare Earth nuclei are investigated and excellent agreement with recent experimental data is observed.Comment: 11 pages (Latex) and 4 figures (available upon request) TUM-ITP-Ko93/

Het empirisch onderzoek naar psychologisch contract: een overzicht.

In deze paper wordt een overzicht gegeven van het bestaande empirisch onderzoek naar psychologisch contract. Achtereenvolgens worden besproken: het onderzoek naar de inhoud van het psychologisch contract, het onderzoek naar de aard van het psychologisch contract, het onderzoek naar de schending en vervulling van het psychologisch contract, en het onderzoek naar het proces van 'psychological contracting'. Voor elk type onderzoek bespreken we telkens welke meetinstrumenten voorhanden zijn, wat de belangrijkste onderzoeksbevindingen zijn en welke beperkingen of mogelijkheden er verbonden zijn aan het betreffende onderzoek. In de laatste paragraaf vatten we de belangrijkste conclusies samen en geven we weer wat het bestaande onderzoek ons leert met betrekking tot toekomstig onderzoek.