Analogue Methods in Palaeoecology: Using the analogue Package

Palaeoecology is an important branch of ecology that uses the subfossil remains of organisms preserved in lake, ocean and bog sediments to inform on changes in ecosystems and the environment through time. The analogue package contains functions to perform modern analogue technique (MAT) transfer functions, which can be used to predict past changes in the environment, such as climate or lake-water pH from species data. A related technique is that of analogue matching, which is concerned with identifying modern sites that are floristically and faunistically similar to fossil samples. These techniques, and others, are increasingly being used to inform public policy on environmental pollution and conservation practices. These methods and other functionality in analogue are illustrated using the Surface Waters Acidification Project diatom:pH training set and diatom counts on samples of a sediment core from the Round Loch of Glenhead, Galloway, Scotland. The paper is aimed at palaeoecologists who are familiar with the techniques described but not with R.

Analogue Methods in Palaeoecology: Using the analogue Package

Palaeoecology is an important branch of ecology that uses the subfossil remains of organisms preserved in lake, ocean and bog sediments to inform on changes in ecosystems and the environment through time. The analogue package contains functions to perform modern analogue technique (MAT) transfer functions, which can be used to predict past changes in the environment, such as climate or lake-water pH from species data. A related technique is that of analogue matching, which is concerned with identifying modern sites that are floristically and faunistically similar to fossil samples. These techniques, and others, are increasingly being used to inform public policy on environmental pollution and conservation practices. These methods and other functionality in analogue are illustrated using the Surface Waters Acidification Project diatom:pH training set and diatom counts on samples of a sediment core from the Round Loch of Glenhead, Galloway, Scotland. The paper is aimed at palaeoecologists who are familiar with the techniques described but not with R

Modelling Palaeoecological Time Series Using Generalised Additive Models

In the absence of annual laminations, time series generated from lake sediments or other similar stratigraphic sequences are irregularly spaced in time, which complicates formal analysis using classical statistical time series models. In lieu, statistical analyses of trends in palaeoenvironmental time series, if done at all, have typically used simpler linear regressions or (non-) parametric correlations with little regard for the violation of assumptions that almost surely occurs due to temporal dependencies in the data or that correlations do not provide estimates of the magnitude of change, just whether or not there is a linear or monotonic trend. Alternative approaches have used Loess-estimated trends to justify data interpretations or test hypotheses as to the causal factors without considering the inherent subjectivity of the choice of parameters used to achieve the Loess fit (e.g., span width, degree of polynomial). Generalised additive models (GAMs) are statistical models that can be used to estimate trends as smooth functions of time. Unlike Loess, GAMs use automatic smoothness selection methods to objectively determine the complexity of the fitted trend, and as formal statistical models, GAMs, allow for potentially complex, non-linear trends, a proper accounting of model uncertainty, and the identification of periods of significant temporal change. Here, I present a consistent and modern approach to the estimation of trends in palaeoenvironmental time series using GAMs, illustrating features of the methodology with two example time series of contrasting complexity; a 150-year bulk organic matter δ15N time series from Small Water, UK, and a 3,000-year alkenone record from Braya-Sø, Greenland. I discuss the underlying mechanics of GAMs that allow them to learn the shape of the trend from the data themselves and how simultaneous confidence intervals and the first derivatives of the trend are used to properly account for model uncertainty and identify periods of change. It is hoped that by using GAMs greater attention is paid to the statistical estimation of trends in palaeoenvironmental time series leading to more a robust and reproducible palaeoscience

A Presentation of the Religious Content on the Most Visited Croatian Internet Portals

Kompleksan međuodnos religije i medija predmet je zanimanja brojnih teoretičara. Stavivši u središte svoga interesa religiju u medijima (u smislu pojavljivanja i prezentacije institucionalnih religija u medijima), nastojalo se dobiti uvid u način na koji je ona predstavljana na trima najposjećenijim hrvatskim mrežnim portalima (24sata.hr, Index.hr i Net.hr) prema podacima koje je Gemius iznio za Hrvatsku. Istraživanja su pokazala da hrvatski građani imaju najviše povjerenja u informacije objavljene na mreži, a ako se tomu pridoda da je 63% građana Hrvatske starije od 15 godina 2011. rabilo mrežu (podaci istraživanja GfK centra), jasno je da su hrvatski mrežni portali važan čimbenik u oblikovanju javne sfere i hrvatske društvene stvarnosti. S druge strane, činjenica je i da zbog pritiska radi povećanja posjećenosti, što u konačnici rezultira povećanjem profita, mrežni portali pribjegavaju tabloidizaciji sadržaja, negativizmu, banalnim i šokantnim vijestima. Svrha je ovoga rada utvrditi na koji se način na najposjećenijim hrvatskim portalima predstavlja religijski sadržaj. Cilj je bio analizirati priloge o religiji koji su objavljivani na naslovnoj stranici triju najposjećenijih hrvatskih mrežnih portala. Analizom sadržaja njihovih naslovnica u razdoblju od 20. studenoga do 20. prosinca 2012. godine nastojalo se utvrditi koliko se tabloidni pristup novinarstvu odnosi na religijske sadržaje, odnosno koja su osnovna obilježja priloga s religijskom tematikom.The complex interplay between religion and the media is the subject of interest of many theorists. Thus, by focusing on the topic of religion in the media (in terms of appearance and presentation of institutional religion in the media), we have tried to gain insight into the way in which religion is presented on the three most visited Croatian Internet portals (24sata.hr, Index.hr and Net.hr, according to the GemiusAudience data for Croatia). Studies have shown that Croatian citizens place most of their confidence in the information available on the Internet. Also, 63% of Croatian citizens above the age of 15 availed themselves of the Internet in 2011 according to GfK research. It is clear therefore that Croatian Internet portals are an important factor in shaping the public sphere as well as Croatian social reality. On the other hand, due to the pressure for increased usage, ultimately resulting in increased profits, the fact remains that Internet portals have resorted to the tabloidization of content, negativism and reporting of banal and shocking news. The purpose of this article was to determine the way in which religious content is presented on the three most visited Croatian Internet portals. The aim was to analyze religious articles published on the front page of these portals with regard to the period between November 20 to December 20, 2012, and in so doing to try to determine in how far the tabloid approach to journalism applies to religious content, that is, to determine the main features of articles with religious themes

Activation of the Large-Conductance, Voltage, and Ca2+- Activated K+ (BK) Channel in Acute Spinal Cord Injury in the Wistar Rat Is Neuroprotective

Context/Objectives: Spinal cord injury (SCI) results in significant neuronal and glial cell death resulting in impaired neurological and motor function. Uncontrolled Ca2+ entry results in excitotoxicity and cell death. In this study, we examine the use of a BK channel activator, Isopimaric acid (ISO), as a neuroprotective agent post-SCI as this channel is involved in regulating Ca2+ entry.Design:By using a 25-g clip compression at the T6 level, we generated a SCI event in wistar rats. At 1 h post-injury we administered ISO (BK channel activator), the BK channel inhibitor iberiotoxin (IbTx), or a vehicle control for 4 weeks via mini osmotic pump (pump capacity). For 8 weeks post-injury, gait analysis of motor function was performed. At the end of 8 weeks, the extent of myelination in the spinal cord was assessed in addition to the electrophysiological profile.Results:Our immunohistological data suggests that ISO treatment leads to an increase or preservation of myelinated axonal tracts. This was further supported by our electrophysiological studies which demonstrate higher compound action potential amplitudes and speed of transmission in ISO-treated animals compared to inj-non-treated. Finally, treatment with ISO significantly improved motor function in our test model.Conclusion: In conclusion, activation of the BK channel during acute SCI may be a novel therapeutic target for acute SCI

A Bayesian palaeoenvironmental transfer function model for acidified lakes

A Bayesian approach to palaeoecological environmental reconstruction deriving from the unimodal responses generally exhibited by organisms to an environmental gradient is described. The approach uses Bayesian model selection to calculate a collection of probability-weighted, species-specific response curves (SRCs) for each taxon within a training set, with an explicit treatment for zero abundances. These SRCs are used to reconstruct the environmental variable from sub-fossilised assemblages. The approach enables a substantial increase in computational efficiency (several orders of magnitude) over existing Bayesian methodologies. The model is developed from the Surface Water Acidification Programme (SWAP) training set and is demonstrated to exhibit comparable predictive power to existing Weighted Averaging and Maximum Likelihood methodologies, though with improvements in bias; the additional explanatory power of the Bayesian approach lies in an explicit calculation of uncertainty for each individual reconstruction. The model is applied to reconstruct the Holocene acidification history of the Round Loch of Glenhead, including a reconstruction of recent recovery derived from sediment trap data.The Bayesian reconstructions display similar trends to conventional (Weighted Averaging Partial Least Squares) reconstructions but provide a better reconstruction of extreme pH and are more sensitive to small changes in diatom assemblages. The validity of the posteriors as an apparently meaningful representation of assemblage-specific uncertainty and the high computational efficiency of the approach open up the possibility of highly constrained multiproxy reconstructions

Variance and Rate-of-Change as Early Warning Signals for a Critical Transition in an Aquatic Ecosystem State: A Test Case From Tasmania, Australia

Critical transitions in ecosystem states are often sudden and unpredictable. Consequently, there is a concerted effort to identify measurable early warning signals (EWS) for these important events. Aquatic ecosystems provide an opportunity to observe critical transitions due to their high sensitivity and rapid response times. Using palaeoecological techniques, we can measure properties of time series data to determine if critical transitions are preceded by any measurable ecosystem metrics, that is, identify EWS. Using a suite of palaeoenvironmental data spanning the last 2,400 years (diatoms, pollen, geochemistry, and charcoal influx), we assess whether a critical transition in diatom community structure was preceded by measurable EWS. Lake Vera, in the temperate rain forest of western Tasmania, Australia, has a diatom community dominated by Discostella stelligera and undergoes an abrupt compositional shift at ca. 820 cal yr BP that is concomitant with increased fire disturbance of the local vegetation. This shift is manifest as a transition from less oligotrophic acidic diatom flora (Achnanthidium minutissimum, Brachysira styriaca, and Fragilaria capucina) to more oligotrophic acidic taxa (Frustulia elongatissima, Eunotia diodon, and Gomphonema multiforme). We observe a marked increase in compositional variance and rate-of-change prior to this critical transition, revealing these metrics are useful EWS in this system. Interestingly, vegetation remains complacent to fire disturbance until after the shift in the diatom community. Disturbance taxa invade and the vegetation system experiences an increase in both compositional variance and rate-of-change. These trends imply an approaching critical transition in the vegetation and the probable collapse of the local rain forest system