Patterns of plant diversity in beech forests of Central Germany

Diese Arbeit entwickelt eine Hypothese zum entstehungsgeschichtlichen Zusammenhang von Co-Evolution/ Syngenese und Phytodiversität von Buchenwäldern unterschiedlicher Standorte. Dieser Zusammenhang wird anhand von exemplarischen Daten und davon abgeleiteten Indizien herausgearbeitet. Dazu wurden Datensätze naturnaher Buchenwälder auf nährstoffarm-sauren Böden (61 Vegetationsaufnahmen aus Steigerwald und Hochspessart) und auf basenreichen Kalkstandorten (51 Vegetationsaufnahmen aus dem Hainich) berücksichtigt und Ähnlichkeiten in ihrer Artenkombination der Waldgesellschaften, ihren Artenzahlen, Arten-Akkumulationskurven und Ellenberg-Lichtzeigerwerten analysiert. Aus der Kombination unserer Analysen zu Phytodiversitätsmustern in Raum und Zeit fanden wir folgende Zusammenhänge. Die bekannte Gefäßpflanzen-Artenarmut von Buchenwäldern auf sauren Standorten (Luzulo-Fagetum 11 Arten, Galio odorati-Fagetum 14 Arten), gegenüber jener auf Kalkstandorten (Hordelymo-Fagetum 35 Arten) wurde bestätigt, was mit der Nährstoffmangelgrenze zahlreicher Arten der Fagetalia sylvaticae hinreichend erklärbar ist. Sie erklärt allerdings nicht das ebenfalls nur sehr spärliche Auftreten von anspruchlosen Arten der Quercetalia robori-petraeae in bodensauren Buchenwäldern und deren niedrigen Diversitätswerte auf sämtlichen Skalenebenen (α-, β- und γ-Diversität). Deshalb gehen wir davon aus, dass die Phytodiversitäts-Kontraste zwischen den Buchenwäldern durch entstehungsgeschichtliche Aspekte verstärkt wurden. Während die licht- und wärmebedürftigeren Arten der ursprünglichen Eichenwälder auf bodensauren Standorten mit der holozänen Buchenausbreitung ausgedunkelt und verdrängt wurden (Schatten-Intoleranz), wurde die schattenfeste Artenvielfalt der ursprünglichen dunklen Laubwälder auf basenreichen Standorten im Buchwald konserviert (Schatten-Toleranz).This article develops a hypothesis on spatial vegetation patterns within beech forests dominated by Fagus sylvatica. The hypothesis was revealed on an exemplary dataset of beech forests on acidic-oligotrophic soils (61 relevés from Steigerwald and Spessart) and on eutrophic calcareous sites (51 relevés from Hainich) with the aim to describe implications that might result from the young post-glacial vegetation history of Central European beech forests. We infer a cause-and-effect relationship between appropriate variables concerning species combinations, species numbers, speciesarea- curves, and Ellenberg indicator values for light with indication for our hypothesis - but without conclusive causality by using an exemplary dataset. Combining our analyses for patterns in space and time we found the following results. The well-known species poorness of beech forests on acidic, oligo- to mesotrophic sites (Luzulo-Fagetum 11 species, Galio odorati-Fagetum 14 species), against those on calcareous sites (Hordelymo-Fagetum 35 species) was confirmed, explicable by limits of nutrient supply for many species of Fagetalia sylvaticae . But the limit does not explain the sparse and infrequent occurrence of frugal Quercetalia robori-petraeae species as well as the low values for all species diversity levels (α-, β- and γ-diversity). Therefore we conclude that the contrast of very low plant diversity between a) beech forest on low-nutrient acidic sites and b) high plant diversity on rich-alkali sites was amplified by biological interactions between the hereditary flora and beech expansion. The hereditary flora on oligotrophic-acidic sites consisted of warmth and light demanding oak forest species and hence was shadowed out (shadow intolerance). However, the flora on eutrophic-calcareous sites consisted of shade-tolerant species of former linden-elm-mixed forests and was easily incorporated in cool-shady beech dominated forests (shadow tolerance)

Shade tolerance of tree species : an analysis based on the databank of Bavarian natural forest reserves

Anhand eines Datensatzes von 1.708 Vegetationsaufnahmen aus 154 bayerischen Naturwaldreservaten wurde die realisierte ökologische Nische von 25 Baumarten hinsichtlich Lichtbedarf bzw. Schattentoleranz untersucht. Für jede Baumart wurde die Stetigkeit des Vorkommens in Baumschicht und Verjüngung berechnet. Für jede Aufnahme wurde die dem Bestandesunterwuchs zur Verfügung stehende Lichtmenge durch Berechnung des mittleren ungewichteten Licht-Zeigerwertes (mL) aller vorkommenden Arten (ohne Baumschicht) auf einer Relativskala geschätzt. Für jede 0,5-Einheiten-Stufe von mL wurde die Präferenz jeder Baumart, getrennt nach Baum- (> 5m) und Verjüngungsschicht (< 5m), als Differenz zwischen relativer Häufigkeit der jeweiligen Art und der relativen Häufigkeit aller Aufnahmen in der mL-Stufe im gesamten Datensatz berechnet. Die Präferenzprofile von Baumschicht und Verjüngungsschicht bildeten die Grundlage einer numerischen Klassifikation von 6 lichtökologischen Nischen typen. Diese Typen werden hinsichtlich ihrer Bindung an bestimmte Entwicklungsphasen und Strukturen der natürlichen Walddynamik diskutiert, mit geläufigen Einteilungen der Baumarten verglichen und im Hinblick auf eine Prognose des Verhaltens unter sich ändernden Umweltbedingungen ausgewertet. – Während sich Edellaubbäume des Tilio-Acerion in den Reservaten sehr ähnlich wie Fagus und Abies verhalten, bilden die Baumarten der Eichenmischwälder eine lichtökologische Gruppe mit rückläufiger Verjüngungstendenz. Unter den übrigen Halbschattbaumarten hebt sich eine Gruppe heraus, welche sich in geschlossenen Beständen vorausverjüngt und nach Störung in die Baumschicht vordringt. Pionierbaumarten bleiben in Naturwaldreservaten weitestgehend auf Sonderstandorte, wo ihre Verjüngung viel Licht vorfindet, beschränkt.On the basis of 1,708 phytosociological relevés from 154 natural forest reserves in Bavaria, the ecological niche of 25 tree species with respect to shade tolerance was investigated. Constancy of occurrence of species was calculated separately for tree and regeneration layer. For each relevé relative light availability was estimated by calculating unweighted averages of Ellenberg values for light (mL) for all plant species occurring in the forest understorey. For each 0.5 segment of mL the preference of the tree species, differentiated by tree layer and regeneration, was calculated as the difference between relative frequency of occurrence and frequency of the mL-segment in the entire data set. Preference profiles of tree layer and regeneration formed the basis of a numerical classification of six types of shade tolerance, which are discussed with respect to their role in certain stages and structures of natural forest dynamics, compared to existing categorisations and interpreted with respect to future succession under environmental change. – While deciduous trees of the ash-sycamore maple group (Tilio-Acerion) behave very similarly to Fagus and Abies in the reserves, tree species of mixed oak woodlands form a group with a tendency towards decreasing regeneration. Among the remaining semi-tolerant species one group is conspicuous for the ability to establish advance-regeneration in rather closed stands and, after disturbances, to grow into the canopy. Shade-intolerant pioneer species remain largely restricted to suitable extreme habitats with ample light availability

Effects of Video Enhancement in a Stated-Choice Experiment on Medical Decision Making

Background. The internet can be useful in administering stated-choice experiments to understand medical decision making and refine the content of patient decision aids. In internet-based stated-choice experiments, video and audio files can be used to provide information to respondents. Quality of data may or may not be affected. Objectives. In a methodological experiment concerned with administration of a stated-choice experiment on the internet concerned with knee-replacement surgery, we compared the data quality obtained with video-enhanced and conventional text formats. Methods. Members of the RAND Corporation’s American Life Panel and 50 years of age or older (n=1616) were randomly assigned to one of two survey modes: video (80%) or text (20%). Quality of data was measured by both the frequency of respondent speeding and plausibility of respondent choices. Results. Typical respondents completed the research task much more rapidly in the text condition than the video condition (10.6 versus 16.4 minutes). The choices were 5 to 10% more likely to be plausible for those in the video-enhanced condition than for those in the text version. The mode of administration did not affect respondents in the extent of their reported interest in the survey or in the degree to which they reported identifying with patients in vignettes. Conclusions. The advantages of the video enhancement in engaging respondents appeared to be offset by the greater time demands on respondents. Video-enhancements in stated-choice experiments may be most useful when used selectively to deliver information that cannot be delivered adequately by text

Towards a research base for implementation strategies addressing mathematics teachers and facilitators

Implementing innovations in mathematics education relies on scaling up professional development (PD) for mathematics teachers. Within the German Center of Mathematics Teacher Education (DZLM), the complexities involved in scaling-up processes are addressed with three implementation strategies: a material, a personnel, and a systemic strategy. For each of them, the research base is empirically established by design research and intervention studies. The personnel strategy focuses on preparing teachers for innovative teaching approaches and on preparing PD facilitators for conducting PDs on the content involved. The empirical research required for creating a research base for the personnel strategy investigates what teachers and facilitators need to know about their learners (students on the classroom level, teachers on the PD level) with regard to a specific (PD) content. The main focus of the material strategy is to provide support for teachers and facilitators by adaptable curriculum materials for classrooms and PD sessions. The empirical research on the material strategies focuses on how such material needs to be constructed to ensure both flexibility and fidelity for impactful quality implementation. The systemic strategy involves considering the systemic contexts on each level and cooperating with the respective stakeholders (e.g., school principals or regional PD authorities). The corresponding empirical research focuses on the interplay of processes and systemic conditions. In this paper, we present the implementation strategies on different levels, and typical research approaches and results for strengthening their empirical and theoretical bases.Projekt DEALPeer Reviewe

Conceptualizing content-related PD facilitator expertise

Studies of facilitators of professional development (PD) for mathematics teachers have been increasing in order to improve their preparation for conducting PD. However, specifications of what facilitators should learn often lack a conceptualization that captures facilitators’ expertise for different PD content. In this article, we provide a framework for facilitator expertise that is in line with current conceptualizations but makes explicit the content-related aspects of such expertise. The framework for content-related facilitator expertise combines cognitive and situated perspectives and allows unpacking different components at the PD level and the classroom level. Using two illustrative cases of different PD content (probability education in primary school and language-responsive mathematics teaching in secondary school), we exemplify how the framework can help to analyze facilitators’ practices in content-related ways in a descriptive mode. This analysis reveals valuable insights that support designers of facilitator preparation programs to specify what facilitators should learn in a prescriptive mode. We particularly emphasize the importance of working on content-related aspects, unpacking the PD content goals into the content knowledge and pedagogical content knowledge elements on the classroom level and developing facilitators’ pedagogical content knowledge on the PD level (PCK-PD), which includes curricular knowledge, as well as knowledge about teachers’ typical thinking about a specific PD content. Situated learning opportunities in facilitator preparation programs can support facilitators to activate these knowledge elements for managing typical situational demands in PD.German-Israeli Foundation for Scientific Research and Development http://dx.doi.org/10.13039/501100001736Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Deutsche Telekom Stiftung http://dx.doi.org/10.13039/501100002990IPN – Leibniz-Institut für die Pädagogik der Naturwissenschaften und Mathematik an der Universität Kiel (3469)Peer Reviewe

Five principles for high-quality mathematics teaching: Combining normative, epistemological, empirical, and pragmatic perspectives for specifying the content of professional development

The academic search for principles of high-quality subject-matter teaching has been informed by different perspectives, in particular normative, epistemological, empirical, and pragmatic perspectives. While these perspectives have sometimes been treated as competing, we emphasize the need of their integration to identify sets of principles that can inform professional development programs for quality development. This paper starts from characterizing the four perspectives, and then shows how they are iteratively intertwined in providing a research base for specifying high-quality principles for teaching, in our case exemplified for the school subject mathematics. For this goal, we present the set of five principles that we have deemed as core principles for a new nationwide, ten-year professional development program in Germany: Conceptual Focus, Cognitive Demand, Student Focus and Adaptivity, Longitudinal Coherence, and Enhanced Communication. We will discuss these five principles against their backgrounds stemming from combing normative, epistemological, empirical, and pragmatic perspectives. This set of principles serves as an exemplary case to substantiate our general argumentation that contemporary educational research and professional development activities should not choose between perspectives but strive for combining them.Peer Reviewe

Social networks, decision aids, and patient decisions regarding knee-replacement surgery

Objective: Examine how information from social networks is associated with patient decisions in the presence of information from multiple professional sources including decision aids. Methods: We conducted a stated-choice experiment in which respondents made recommendations for hypothetical patients about whether full knee-replacement surgery should be performed to treat knee osteoarthritis. In addition, we administered a background questionnaire in which we explicitly asked respondents about the experience of people in their social network with knee osteoarthritis and possible treatment options. We examined the manner in which respondents’ recommendations for vignette persons were associated with the experiences of members of their own social networks. Results: Controlling for the information obtained from professional sources, satisfaction with full knee-replacement surgery within the respondents’ social networks was strongly associated with respondent decisions. Conclusion: Information from the social network may complement or compete with information from professional sources as patients make decisions. Practice Implications: Professionals should offer to assist patients in making sound use information they obtain from their social networks

Comparison of the Effects of Early Pregnancy with Human Interferon, Alpha 2 (IFNA2), on Gene Expression in Bovine Endometrium

Interferon tau (IFNT), a type I IFN similar to alpha IFNs (IFNA), is the pregnancy recognition signal produced by the ruminant conceptus. To elucidate specific effects of bovine IFNT and of other conceptus-derived factors, endometrial gene expression changes during early pregnancy were compared to gene expression changes after intrauterine application of human IFNA2. In experiment 1, endometrial tissue samples were obtained on Day (D) 12, D15, and D18 postmating from nonpregnant or pregnant heifers. In experiment 2, heifers were treated from D14 to D16 of the estrous cycle with an intrauterine device releasing IFNA2 or, as controls, placebo lipid extrudates or PBS only. Endometrial biopsies were performed after flushing the uterus. All samples from both experiments were analyzed with an Affymetrix Bovine Genome Array. Experiment 1 revealed differential gene expression between pregnant and nonpregnant endometria on D15 and D18. In experiment 2, IFNA2 treatment resulted in differential gene expression in the bovine endometrium. Comparison of the data sets from both studies identified genes that were differentially expressed in response to IFNA2 but not in response to pregnancy on D15 or D18. In addition, genes were found that were differentially expressed during pregnancy but not after IFNA2 treatment. In experiment 3, spatiotemporal alterations in expression of selected genes were determined in uteri from nonpregnant and early pregnant heifers using in situ hybridization. The overall findings of this study suggest differential effects of bovine IFNT compared to human IFNA2 and that some pregnancy-specific changes in the endometrium are elicited by conceptus-derived factors other than IFNT

Predictive validity of a brief antiretroviral adherence index: Retrospective cohort analysis under conditions of repetitive administration

<p>Abstract</p> <p>Background</p> <p>Newer antiretroviral (ARV) agents have improved pharmacokinetics, potency, and tolerability and have enabled the design of regimens with improved virologic outcomes. Successful antiretroviral therapy is dependent on patient adherence. In previous research, we validated a subset of items from the ACTG adherence battery as prognostic of virologic suppression at 6 months and correlated with adherence estimates from the Medication Event Monitoring System (MEMS). The objective of the current study was to validate the longitudinal use of the Owen Clinic adherence index in analyses of time to initial virologic suppression and maintenance of suppression.</p> <p>Results</p> <p>278 patients (naïve n = 168, experienced n = 110) met inclusion criteria. Median [range] time on the first regimen during the study period was 286 (30 – 1221) days. 217 patients (78%) achieved an undetectable plasma viral load (pVL) at median 63 days. 8.3% (18/217) of patients experienced viral rebound (pVL > 400) after initial suppression. Adherence scores varied from 0 – 25 (mean 1.06, median 0). The lowest detectable adherence score cut point using this instrument was ≥ 5 for both initial suppression and maintenance of suppression. In the final Cox model of time to first undetectable pVL, controlling for prior treatment experience and baseline viral load, the adjusted hazard ratio for time updated adherence score was 0.36_{score ≥ 5}(95% CI: 0.19–0.69) [reference: <5]. In the final generalized estimating equations (GEE) logistic regression model the adjusted odds ratio for time-updated adherence score was 0.17_{score ≥ 5}(0.05–0.66) [reference: <5].</p> <p>Conclusion</p> <p>A brief, longitudinally administered self report adherence instrument predicted both initial virologic suppression and maintenance of suppression in patients using contemporary ARV regimens. The survey can be used for identification of sub-optimal adherence with subsequent appropriate intervention.</p