Age modeling of young non-varved lake sediments: methods and limits. Examples from two lakes in Central Chile

High-resolution and highly precise age models for recent lake sediments (last 100–150 years) are essential for quantitative paleoclimate research. These are particularly important for sedimentological and geochemical proxies, where transfer functions cannot be established and calibration must be based upon the relation of sedimentary records to instrumental data. High-precision dating for the calibration period is most critical as it determines directly the quality of the calibration statistics. Here, as an example, we compare radionuclide age models obtained on two high-elevation glacial lakes in the Central Chilean Andes (Laguna Negra: 33°38′S/70°08′W, 2,680 m a.s.l. and Laguna El Ocho: 34°02′S/70°19′W, 3,250 m a.s.l.). We show the different numerical models that produce accurate age-depth chronologies based on 210Pb profiles, and we explain how to obtain reduced age-error bars at the bottom part of the profiles, i.e., typically around the end of the 19th century. In order to constrain the age models, we propose a method with five steps: (i) sampling at irregularly-spaced intervals for 226Ra, 210Pb and 137Cs depending on the stratigraphy and microfacies, (ii) a systematic comparison of numerical models for the calculation of 210Pb-based age models: constant flux constant sedimentation (CFCS), constant initial concentration (CIC), constant rate of supply (CRS) and sediment isotope tomography (SIT), (iii) numerical constraining of the CRS and SIT models with the 137Cs chronomarker of AD 1964 and, (iv) step-wise cross-validation with independent diagnostic environmental stratigraphic markers of known age (e.g., volcanic ash layer, historical flood and earthquakes). In both examples, we also use airborne pollutants such as spheroidal carbonaceous particles (reflecting the history of fossil fuel emissions), excess atmospheric Cu deposition (reflecting the production history of a large local Cu mine), and turbidites related to historical earthquakes. Our results show that the SIT model constrained with the 137Cs AD 1964 peak performs best over the entire chronological profile (last 100–150 years) and yields the smallest standard deviations for the sediment ages. Such precision is critical for the calibration statistics, and ultimately, for the quality of the quantitative paleoclimate reconstruction. The systematic comparison of CRS and SIT models also helps to validate the robustness of the chronologies in different sections of the profile. Although surprisingly poorly known and under-explored in paleolimnological research, the SIT model has a great potential in paleoclimatological reconstructions based on lake sediments

Bedeutung der Arbeitsallianz in der Psychotherapie

Das pantheoretische Konzept der Arbeitsallianz stellt die kollaborative Qualität der an der Therapie beteiligten Personen (i. e. zumeist der Patient und der Therapeut) in den Mittelpunkt. Die Arbeitsallianz ist die weltweit am besten untersuchte Prozessvariable in der Psychotherapie. Die vorliegende Arbeit bietet einen Überblick über den aktuellen metaanalytischen Wissensstand. Basierend auf 200 Primärstudien mit 14.000 teilnehmenden Patienten wurde der Zusammenhang zwischen Arbeitsallianz und Therapieerfolg metaanalytisch untersucht. Die Arbeitsallianz erweist sich als äußerst robuster Prädiktor, der moderate 8 % der Varianz des Therapieerfolgs erklärt. Der Zusammenhang über die verschiedenen Psychotherapietraditionen hinweg zeigte sich sowohl unter randomisierten kontrollierten, manualisierten Studienbedingungen als auch unter naturalistischen Voraussetzungen. Der Effekt fand sich zudem in den störungsspezifischen Erfolgseinschätzungen und den generelleren Erfolgsmaßen. Die moderaten Therapeuteneffekte in den Primärstudien konnten metaanalytisch bestätigt werden. Soziokulturelle Aspekte wie Substanzmissbrauch und ethnische Minoritäten moderieren den Einfluss zwischen Arbeitsallianz und Therapieerfolg. Die Nähe der Forscher zum Allianzkonzept („allegiance“) beeinflusst die Vorhersagekraft der frühen Allianz zwar statistisch bedeutsam, jedoch nicht substanziell.

Multiplex assays for biomarker research and clinical application: translational science coming of age

Over the last decade, translational science has come into the focus of academic medicine, and significant intellectual and financial efforts have been made to initiate a multitude of bench-to-bedside projects. The quest for suitable biomarkers that will significantly change clinical practice has become one of the biggest challenges in translational medicine. Quantitative measurement of proteins is a critical step in biomarker discovery. Assessing a large number of potential protein biomarkers in a statistically significant number of samples and controls still constitutes a major technical hurdle. Multiplexed analysis offers significant advantages regarding time, reagent cost, sample requirements and the amount of data that can be generated. The two contemporary approaches in multiplexed and quantitative biomarker validation, antibody-based immunoassays and MS-based multiple (or selected) reaction monitoring, are based on different assay principles and instrument requirements. Both approaches have their own advantages and disadvantages and therefore have complementary roles in the multi-staged biomarker verification and validation process. In this review, we discuss quantitative immunoassay and multiple reaction monitoring/selected reaction monitoring assay principles and development. We also discuss choosing an appropriate platform, judging the performance of assays, obtaining reliable, quantitative results for translational research and clinical applications in the biomarker field.

Quantitative and qualitative research approaches to assess student well-being

Although there is dissimiliarity in theoretical research approaches to subjective well-being and to assessments of well-being, there is agreement regarding the value of well-being, especially among student populations. In the highly structured, achievement-oriented, non-optimal context of a classroom, individual well-being is a necessary pre-condition for learning. Among student populations well-being should not be construed as an achievement enhancer; but, rather, recognized and measured as an educational value of its own. However, it is necessary for the positive bias towards learning at least in highly structured, achievement-orientated, non-optional learning contexts like school [cf. Hascher, T. (2004). Wohlbefinden in der Schule. Münster: Waxmann]. How can it be measured? Since different research approaches lead to a variety of instruments, the following paper will focus on two ways of assessing well-being in school: a questionnaire on student well-being (N = 2014) 1 and a semi-structured daily diary about relevant emotional situations in school (N = 58, period 3 × 2 weeks). Both methods are introduced and their methodological quality is discussed in terms of reliability, validity and in terms of their usefulness for improving school practice. Furthermore, the research potential of combining quantitative and qualitative data on students’ well-being is addressed.

Immigrant students’ psychological adjustment in the school context: A meta-synthesis of qualitative research on acculturation

This contribution focuses on the characteristics of the school context and their impact on immigrant students’ acculturation and adjustment at school. Research suggests that the ways immigrants acculturate is related to their well being (e.g. Phinney, et al., 2001; Ward & Rana-Deuba, 1999), although findings have been contradictory across methods and studies (e.g. Rogler, 1991; Escobar & Vega, 2001). Debates in acculturation research currently center on issues of acculturation measurement (e.g. Berry, 2009; Rudmin, 2009), as most research is conducted in the quantitative tradition. In addition, some have suggested (Birman, 2011) that research on acculturation in the tradition of cross-cultural psychology adopts an overly individualistic perspective, and lacks attention to the specific contexts of acculturation. Alternatively, the contextual approach proposes that the relationship between acculturation and adjustment is shaped by the surrounding context (Birman & Simon, 2013). For immigrant children, schools are the setting where the process of acculturation unfolds, and an important context in which to study their adjustment and well being (Birman, et al., 2007; Makarova & Herzog, 2011). Though rarely used in this tradition of acculturation research (Chirkov, 2009), qualitative methods are uniquely suited to gain insight to facilitate theory development, as well as appreciate the contextual nature of the acculturation process. Yet we are not aware of efforts to synthesize the empirical qualitative literature on this topic. Applying the methodology of meta-synthesis for qualitatieve research (Walsh & Downe, 2005) our contribution attempts to integrate results from qualitative studies on impact of acculturation on immigrant students’ psychological adjustment in the school context. For this purpose 84 articles which matched the inclusion criteria were selected. Overall, the results of our study show that within the school context a number of structural as well as process characteristics can be identified as crucial for immigrant youth psychological adjustment. Moreover, our findings indicate that immigrant youths’ psychological adjustment is related to other individual outcomes of acculturation in the school context such as behavioral adjustment, peer-relationships, academic achievement and identity development of immigrant youth.