TY  - JOUR
A1  - Hake, Tim
A1  - Bodenberger, Bernhard
A1  - Groth, Detlef
T1  - In Python available: St. Nicolas House Algorithm (SNHA) with bootstrap support for improved performance in dense networks
JF  - Human biology and public health
N2  - The St. Nicolas House Algorithm (SNHA) finds association chains of direct dependent variables in a data set. The dependency is based on the correlation coefficient, which is visualized as an undirected graph. The network prediction is improved by a bootstrap routine. It enables the computation of the empirical p-value, which is used to evaluate the significance of the predicted edges. Synthetic data generated with the Monte Carlo method were used to firstly compare the Python package with the original R package, and secondly to evaluate the predicted network using the sensitivity, specificity, balanced classification rate and the Matthew's correlation coefficient (MCC). The Python implementation yields the same results as the R package. Hence, the algorithm was correctly ported into Python. The SNHA scores high specificity values for all tested graphs. For graphs with high edge densities, the other evaluation metrics decrease due to lower sensitivity, which could be partially improved by using bootstrap,while for graphs with low edge densities the algorithm achieves high evaluation scores. The empirical p-values indicated that the predicted edges indeed are significant.
KW  - Python
KW  - correlation
KW  - network reconstruction
KW  - bootstrap
KW  - St. Nicolas House Algorithm
Y1  - 2023
U6  - https://doi.org/10.52905/hbph2023.1.63
SN  - 2748-9957
VL  - 1
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Dietze, Michael
A1  - Krautblatter, Michael
A1  - Illien, Luc
A1  - Hovius, Niels
T1  - Seismic constraints on rock damaging related to a failing mountain peak
BT  - The Hochvogel, Allgäu
JF  - Earth surface processes and landforms
N2  - Large rock slope failures play a pivotal role in long-term landscape evolution and are a major concern in land use planning and hazard aspects. While the failure phase and the time immediately prior to failure are increasingly well studied, the nature of the preparation phase remains enigmatic. This knowledge gap is due, to a large degree, to difficulties associated with instrumenting high mountain terrain and the local nature of classic monitoring methods, which does not allow integral observation of large rock volumes. Here, we analyse data from a small network of up to seven seismic sensors installed during July-October 2018 (with 43 days of data loss) at the summit of the Hochvogel, a 2592 m high Alpine peak. We develop proxy time series indicative of cyclic and progressive changes of the summit. Modal analysis, horizontal-to-vertical spectral ratio data and end-member modelling analysis reveal diurnal cycles of increasing and decreasing coupling stiffness of a 260,000 m(3) large, instable rock volume, due to thermal forcing. Relative seismic wave velocity changes also indicate diurnal accumulation and release of stress within the rock mass. At longer time scales, there is a systematic superimposed pattern of stress increased over multiple days and episodic stress release within a few days, expressed in an increased emission of short seismic pulses indicative of rock cracking. Our data provide essential first order information on the development of large-scale slope instabilities towards catastrophic failure. (c) 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd
KW  - environmental seismology
KW  - fatigue
KW  - fundamental frequency
KW  - HVSR
KW  - mass
KW  - wasting
KW  - mountain geomorphology
KW  - natural hazard
KW  - noise cross
KW  - correlation
KW  - seismic monitoring
KW  - slope failure
Y1  - 2021
U6  - https://doi.org/10.1002/esp.5034
SN  - 0197-9337
SN  - 1096-9837
VL  - 46
IS  - 2
SP  - 417
EP  - 429
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bents, Dominik
A1  - Rybak, Alexander
A1  - Groth, Detlef
T1  - Spatial conscript body height correlation of Norwegian districts in the 19th century
JF  - Anthropologischer Anzeiger : journal of biological and clinical anthropology ; Mitteilungsorgan der Gesellschaft für Anthropologie
N2  - Background: We investigated height of Norwegian conscripts in view of the hypothesis of a "community effect on height" using autocorrelation analysis of district heights within a time-span of 20 years at the end of the 19th century and correlations between neighboring districts at this time. Material and methods: After digitalizing available body height data of Norwegian draftees in 1877-1878, 1880 (averaged as 1878), and 1895-1897 (averaged as 1896) we calculated the magnitude of autocorrelation of body height within the same municipality at different time points. Furthermore, we generated three different neighborhood networks, (1) based on Euclidean distances, (2) a minimum spanning tree build on those distances, (3) a network founded on real world road connections. The networks were used to determine the correlation between body height of neighboring districts depending on the number of edges required to connect two municipalities. Results: The autocorrelation value for body heights was around r = 0.5 (for all p < 0.001) in the years 1878 and 1896. The correlation between neighboring districts varied in the Euclidean distance based network between 0.47 and 0.27 approximately for both years in a sorted order, descending from nearest (0-50 km) to farthest (150-200 km, for all p < 0.001). First order neighbors in the minimum spanning tree network correlation was 0.36 in 1878 and 0.42 in 1896 (for all p < 0.001). The values of neighbor correlation in the road connection based network ranged in 1878 from 0.42 (first order neighbors) to 0.17 (forth order neighbors, for all p < 0.01) and in 1896 from 0.46 (first order neighbors) to 0.12 (forth order neighbors, for all p < 0.05). Conclusion: This initial study of Norwegian conscript height data from the 19th century showed significant medium sized effects for the within district autocorrelation between 1878 and 1896 as well as medium neighborhood correlation, slightly lower in comparison to a recent study regarding Swiss conscripts. Digitalizing more data from other years in this and later time spans as well as using older road and ship connections instead of the actual road data might stabilize and improve those findings.
KW  - body height
KW  - correlation
KW  - Norway
KW  - conscripts
KW  - community effect on height
Y1  - 2017
U6  - https://doi.org/10.1127/anthranz/2017/0700
SN  - 0003-5548
SN  - 2363-7099
VL  - 74
IS  - 1
SP  - 65
EP  - 69
PB  - Schweizerbart
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Lebedeva, Lidia
A1  - Groth, Detlef
A1  - Hermanussen, Michael
A1  - Scheffler, Christiane
A1  - Godina, Elena
T1  - The network effects on conscripts' height in the central provinces of Russian empire in the middle of XIX century
BT  - at the beginning of XX century
JF  - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie
N2  - Background: We investigated average body height in the central provinces of the Russian empire in the middle of XIX century in view of the concept of "community effects on height". We analyzed body height correlations between neighboring districts at this time. We added information about secular changes in body height during the 19th century of this territory. Material and methods: The study used height data of conscripts, which were born in the years 1853-1863, and age 21 at the time of measurement. The territory of seven provinces was considered as a network with 105 nodes, each node representing one district with information on average male body height. In order to define neighboring districts three different approaches were used: based on the "common borders" method, based on Euclidean distances (from 60 to 120 km), based on real road connections. Results: Small but significant correlation coefficients were observed between 1st order districts in the network based on Euclidean distance of 100 km (r = 0.256, p-value = 0.006) and based on "the common borders" approach (r = 0.25, p-value = 0.02). Wherein no significant correlations were observed in the network based on road connections and between second order neighbors regardless of the method. Conclusion: Height correlation coefficients between 1st order neighboring districts observed in the Russian districts were very similar to values observed in the Polish study (r = 0.24). The considered Russian territory and the territory of Poland have a lot in common. They consist of both plains without mountains. In contradistinction to Poland the transport infrastructure in Russia was weakly developed in the middle of XIX century. In addition, the mobility of people was limited by serfdom. In this context the absent of significant correlation of second order neighbors can be explained by low population density and lack of migration and communication between the districts.
KW  - body height
KW  - correlation
KW  - conscripts
KW  - community effect on height
KW  - Russian empire
Y1  - 2019
U6  - https://doi.org/10.1127/anthranz/2019/0984
SN  - 0003-5548
VL  - 76
IS  - 5
SP  - 371
EP  - 377
PB  - Schweizerbart
CY  - Stuttgart
ER  - 
TY  - JOUR
A1  - Runge, Alexandra
A1  - Grosse, Guido
T1  - Comparing Spectral Characteristics of Landsat-8 and Sentinel-2 Same-Day Data for Arctic-Boreal Regions
JF  - Remote Sensing
N2  - The Arctic-Boreal regions experience strong changes of air temperature and precipitation regimes, which affect the thermal state of the permafrost. This results in widespread permafrost-thaw disturbances, some unfolding slowly and over long periods, others occurring rapidly and abruptly. Despite optical remote sensing offering a variety of techniques to assess and monitor landscape changes, a persistent cloud cover decreases the amount of usable images considerably. However, combining data from multiple platforms promises to increase the number of images drastically. We therefore assess the comparability of Landsat-8 and Sentinel-2 imagery and the possibility to use both Landsat and Sentinel-2 images together in time series analyses, achieving a temporally-dense data coverage in Arctic-Boreal regions. We determined overlapping same-day acquisitions of Landsat-8 and Sentinel-2 images for three representative study sites in Eastern Siberia. We then compared the Landsat-8 and Sentinel-2 pixel-pairs, downscaled to 60 m, of corresponding bands and derived the ordinary least squares regression for every band combination. The acquired coefficients were used for spectral bandpass adjustment between the two sensors. The spectral band comparisons showed an overall good fit between Landsat-8 and Sentinel-2 images already. The ordinary least squares regression analyses underline the generally good spectral fit with intercept values between 0.0031 and 0.056 and slope values between 0.531 and 0.877. A spectral comparison after spectral bandpass adjustment of Sentinel-2 values to Landsat-8 shows a nearly perfect alignment between the same-day images. The spectral band adjustment succeeds in adjusting Sentinel-2 spectral values to Landsat-8 very well in Eastern Siberian Arctic-Boreal landscapes. After spectral adjustment, Landsat and Sentinel-2 data can be used to create temporally-dense time series and be applied to assess permafrost landscape changes in Eastern Siberia. Remaining differences between the sensors can be attributed to several factors including heterogeneous terrain, poor cloud and cloud shadow masking, and mixed pixels.
KW  - spectral adjustment
KW  - northern high latitudes
KW  - permafrost
KW  - time series
KW  - optical data
KW  - surface reflectance
KW  - correlation
KW  - permafrost disturbances
KW  - land cover change
Y1  - 2019
U6  - https://doi.org/10.3390/rs11141730
SN  - 2072-4292
VL  - 11
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Manning, Pete
A1  - Gossner, Martin M.
A1  - Bossdorf, Oliver
A1  - Allan, Eric
A1  - Zhang, Yuan-Ye
A1  - Prati, Daniel
A1  - Blüthgen, Nico
A1  - Boch, Steffen
A1  - Böhm, Stefan
A1  - Börschig, Carmen
A1  - Hölzel, Norbert
A1  - Jung, Kirsten
A1  - Klaus, Valentin H.
A1  - Klein, Alexandra Maria
A1  - Kleinebecker, Till
A1  - Krauss, Jochen
A1  - Lange, Markus
A1  - Müller, Jörg
A1  - Pasalic, Esther
A1  - Socher, Stephanie A.
A1  - Tschapka, Marco
A1  - Türke, Manfred
A1  - Weiner, Christiane
A1  - Werner, Michael
A1  - Gockel, Sonja
A1  - Hemp, Andreas
A1  - Renner, Swen C.
A1  - Wells, Konstans
A1  - Buscot, Francois
A1  - Kalko, Elisabeth K. V.
A1  - Linsenmair, Karl Eduard
A1  - Weisser, Wolfgang W.
A1  - Fischer, Markus
T1  - Grassland management intensification weakens the associations among the diversities of multiple plant and animal taxa
JF  - Ecology : a publication of the Ecological Society of America
N2  - Land-use intensification is a key driver of biodiversity change. However, little is known about how it alters relationships between the diversities of different taxonomic groups, which are often correlated due to shared environmental drivers and trophic interactions. Using data from 150 grassland sites, we examined how land-use intensification (increased fertilization, higher livestock densities, and increased mowing frequency) altered correlations between the species richness of 15 plant, invertebrate, and vertebrate taxa. We found that 54% of pairwise correlations between taxonomic groups were significant and positive among all grasslands, while only one was negative. Higher land-use intensity substantially weakened these correlations(35% decrease in rand 43% fewer significant pairwise correlations at high intensity), a pattern which may emerge as a result of biodiversity declines and the breakdown of specialized relationships in these conditions. Nevertheless, some groups (Coleoptera, Heteroptera, Hymenoptera and Orthoptera) were consistently correlated with multidiversity, an aggregate measure of total biodiversity comprised of the standardized diversities of multiple taxa, at both high and lowland-use intensity. The form of intensification was also important; increased fertilization and mowing frequency typically weakened plant-plant and plant-primary consumer correlations, whereas grazing intensification did not. This may reflect decreased habitat heterogeneity under mowing and fertilization and increased habitat heterogeneity under grazing. While these results urge caution in using certain taxonomic groups to monitor impacts of agricultural management on biodiversity, they also suggest that the diversities of some groups are reasonably robust indicators of total biodiversity across a range of conditions.
KW  - Biodiversity indicators
KW  - correlation
KW  - fertilization
KW  - grassland management
KW  - grazing
KW  - land-use change
KW  - land-use intensity
KW  - mowing
KW  - multidiversity
KW  - multitrophic interactions
Y1  - 2015
U6  - https://doi.org/10.1890/14-1307.1
SN  - 0012-9658
SN  - 1939-9170
VL  - 96
IS  - 6
SP  - 1492
EP  - 1501
PB  - Wiley
CY  - Washington
ER  -