Spatial and Temporal Evolution of the Volcanics and Sediments of the Kenya Rift

New volumetric and mass flux estimates have been calculated for the Kenya Rift. Spatial and temporal histories for volcanic eruptions, lacustrine deposition, and hominin fossil sites are presented, aided by the compilation of a new digital geologic map. Distribution of volcanism over time indicates several periods of southward expansion followed by relative positional stasis. Volcanism occurs throughout the activated rift length, with no obvious abandonment as the rift system migrated. The main exception is a period of volcanic concentration around 10 Ma, when activity was constrained within 2° of the equator. Volumes derived from seismic data indicate a total volume of c. 310,000 km3 (2.47 x 1010 kg/yr ), which is significantly more than the map-derived volumes found here or published previously. Map-based estimates are likely affected by a bias against recognizing small volume events in the older record. Such events are, however, the main driver of erupted volume over the last 5 Ma. A technique developed here to counter this bias results in convergence of the two volume estimation techniques. Relative erupted composition over time is variable. Overall, the erupted material has a mafic to silicic ratio of 0.9:1. Basalts are distinctly more common in the Turkana region, which previously experienced Mesozoic rifting. Despite the near equal ratio of mafic to silicic products, the Kenya Rift otherwise fits the definition of a SLIP. It is proposed that the compositions would better fit the published definition if the Turkana region was not twice-rifted. Lacustrine sedimentation post-dates initial volcanism by about 5 million years, and follows the same volcanic trends, showing south and eastward migration over time. This sedimentation delay is likely related to timing of fault displacements. Evidence of hominin habitation is distinctly abundant in the northern and southern sections of the Kenya Rift, but there is an observed gap in the equatorial rift between 4 and 0.5 million years ago. After 0.5 Ma, sites appear to progress towards the equator. The pattern and timing of hominid site distributions suggests that the equatorial gap in habitation may be the result of active volcanic avoidance.

The construal of constructions: causal and temporal interpretations in change constructions

In this paper I first discuss some non-causal change constructions which have largely gone unnoticed in the literature, such as The butler bowed the guests in (which is said to code mild causation) and The supporters booed Newcastle off at the interval (which only codes temporal coextension between its two constitutive subevents). Since the same structure (i.e. the transitive object-oriented change construction) can be used to code a wide spectrum of causal and temporal relations, the question arises of what cognitive mechanisms may be involved in such meaning shifts. I argue that variation can be motivated on the basis of the figure/ground segregation which the conceptualiser can impose upon the integrated scene coded by the change construction. The integrated scene depicts a force-dynamic scenario but also evokes a unique temporal setting (i.e. temporal overlap or coextension between the constitutive subevents). Such a “bias” towards temporal overlap can be used by the conceptualiser to background causation and highlight temporal overlap interpretations. It is also shown that figure/ground segregation can be appealed to to account for the causal interpretation of intransitive change constructions, e.g. The kettle boiled dry. If the conceptual distance between the verbal event and the non-verbal event is (relatively) great, causality can be highlighted even in intransitive patterns.

Negative bias of processing ambiguously cued emotional stimuli.

Daily we cope with upcoming potentially disadvantageous events. Therefore, it makes sense to be prepared for the worst case. Such a 'pessimistic' bias is reflected in brain activation during emotion processing. Healthy individuals underwent functional neuroimaging while viewing emotional stimuli that were earlier cued ambiguously or unambiguously concerning their emotional valence. Presentation of ambiguously announced pleasant pictures compared with unambiguously announced pleasant pictures resulted in increased activity in the ventrolateral prefrontal, premotor and temporal cortex, and in the caudate nucleus. This was not the case for the respective negative conditions. This indicates that pleasant stimuli after ambiguous cueing provided 'unexpected' emotional input, resulting in the adaptation of brain activity. It strengthens the hypothesis of a 'pessimistic' bias of brain activation toward ambiguous emotional events.

Neuroanatomy of intergroup bias: A white matter microstructure study of individual differences

Intergroup bias - the tendency to behave more positively towards an ingroup member than an outgroup member - is a powerful social force, for good and ill. And though it is widely demonstrated, intergroup bias is not universal, as it is characterized by significant individual differences. Recently, attention has begun to turn to whether neuroanatomy might explain these individual differences in intergroup bias. However, no research to date has examined whether white matter microstructure could help determine differences in behavior towards ingroup and outgroup members. In the current research, we examine intergroup bias with the third-party punishment paradigm and white matter integrity and connectivity strength as determined by diffusion tensor imaging (DTI). We found that both increased white matter integrity at the right temporal-parietal junction (TPJ) and connectivity strength between the right TPJ and the dorsomedial prefrontal cortex (DMPFC) were associated with increased impartiality in the third-party punishment paradigm, i.e., reduced intergroup bias. Further, consistent with the role that these brain regions play in the mentalizing network, we found that these effects were mediated by mentalizing processes. Participants with greater white matter integrity at the right TPJ and connectivity strength between the right TPJ and the DMPFC employed mentalizing processes more equally for ingroup and outgroup members, and this non-biased use of mentalizing was associated with increased impartiality. The current results help shed light on the mechanisms of bias and, potentially, on interventions that promote impartiality over intergroup bias.

Evaluating Taphonomic Bias in a Storm-Disturbed Carbonate Platform: Effects of Compositional and Environmental Factors in Lower Jurassic Brachiopod Accumulations (Eastern Subbetic Basin, Spain)

In order to evaluate taxonomic and environmental control on the preservation pattern of brachiopod accumulations, sedimentologic and taphonomic data have been integrated with those inferred from the structure of brachiopod accumulations from the easternmost Lower Jurassic Subbetic deposits in Spain. Two brachiopod communities (Praesphaeroidothyris and Securina communities) were distinguished showing a mainly free-lying way of life in soft-bottom habitats. Three taphofacies are discriminated based on proportion of disarticulation, fragmentation, packing, and shell filling. Taphofacies 1 is represented by thinly fragmented, dispersed brachiopod shells in wackestone beds. Taphofacies 2 is spatially restricted to small lenses where shells are poorly fragmented, rarely disarticulated, usually void filled, and highly packed. Taphofacies 3 is represented by mud or cement filled, loosely packed, articulated brachiopods forming large pocket-like structures. Temporal and spatial averaging were minimally involved in taphofacies 2 and 3. It is interpreted that patchy preservation implies preservation of primary original patchiness of brachiopod communities on the seafloor. The origin of shell-rich taphofacies (2 and 3) is related to rapid burial due to episodic storm activity, while shell-poor taphofacies 1 records background conditions. The nature and comparative diversity of these taphofacies underscores the importance of rapid burial for shell beds preservation. Differences in preservation between taphofacies 2 and 3 are mainly related to environmental criteria, most importantly storm energy and water depth. In contrast, the taxonomic-specific pattern of the communities is a subordinate element of control, controlling only minor within-taphofacies differences in preservation.

The temporal binding deficit hypothesis of autism

Frith has argued that people with autism show “weak central coherence,” an unusual bias toward piecemeal rather than configurational processing and a reduction in the normal tendency to process information in context. However, the precise cognitive and neurological mechanisms underlying weak central coherence are still unknown. We propose the hypothesis that the features of autism associated with weak central coherence result from a reduction in the integration of specialized local neural networks in the brain caused by a deficit in temporal binding. The visuoperceptual anomalies associated with weak central coherence may be attributed to a reduction in synchronization of high-frequency gamma activity between local networks processing local features. The failure to utilize context in language processing in autism can be explained in similar terms. Temporal binding deficits could also contribute to executive dysfunction in autism and to some of the deficits in socialization and communication.

Fidelity bias in mollusk assemblages from coastal lagoons of Southern Brazil

The South America southern coast exhibits many outcrops with abundant shell beds, from the Pleistocene through the Recent. How much biological information is preserved within these shell beds? Or, what is the actual probability a living community has to leave a fossil record corresponding to these shell deposits? Although ecological and biogeographical aspects might had been pointed, considering these temporal scales, up to the moment there is no taphonomically-oriented studies available. Quantitative comparisons between living (LAs), death (DAs) and fossil assemblages (FAs) are important not only in strictly taphonomic studies, but have grown a leading tool for conservation paleobiology analysis. Comparing LAs, DAs and FAs from estuaries and lagoons in the Rio Grande do Sul Coastal Plain makes possible to quantitatively understand the nature and quantity of biological information preserved in fossil associations in Holocene lagoon facies. As already noted by several authors, spatial scale parts the analysis, but we detected that the FAs refl ects live ones, rather than dead ones, as previously not realized. The results herein obtained illustrates that species present in DA are not as good preserved in recent (Holocene) fossil record as originally thought. Strictly lagoon species are most prone to leave fossil record. The authors consider that the fi delity pattern here observed for estuarine mollusks to be driven by (i) high temporal and spatial variability in the LAs, (ii) spatial mixing in the DA and (iii) differential preservation of shells, due to long residence times in the taphonomically active zone.

Temporal aggregation of migration counts can improve accuracy and precision of trends

Temporal replicate counts are often aggregated to improve model fit by reducing zero-inflation and count variability, and in the case of migration counts collected hourly throughout a migration, allows one to ignore nonindependence. However, aggregation can represent a loss of potentially useful information on the hourly or seasonal distribution of counts, which might impact our ability to estimate reliable trends. We simulated 20-year hourly raptor migration count datasets with known rate of change to test the effect of aggregating hourly counts to daily or annual totals on our ability to recover known trend. We simulated data for three types of species, to test whether results varied with species abundance or migration strategy: a commonly detected species, e.g., Northern Harrier, Circus cyaneus; a rarely detected species, e.g., Peregrine Falcon, Falco peregrinus; and a species typically counted in large aggregations with overdispersed counts, e.g., Broad-winged Hawk, Buteo platypterus. We compared accuracy and precision of estimated trends across species and count types (hourly/daily/annual) using hierarchical models that assumed a Poisson, negative binomial (NB) or zero-inflated negative binomial (ZINB) count distribution. We found little benefit of modeling zero-inflation or of modeling the hourly distribution of migration counts. For the rare species, trends analyzed using daily totals and an NB or ZINB data distribution resulted in a higher probability of detecting an accurate and precise trend. In contrast, trends of the common and overdispersed species benefited from aggregation to annual totals, and for the overdispersed species in particular, trends estimating using annual totals were more precise, and resulted in lower probabilities of estimating a trend (1) in the wrong direction, or (2) with credible intervals that excluded the true trend, as compared with hourly and daily counts.

Improved models for estimating temporal changes in carbon sequestration in above-ground biomass of mixed-species environmental plantings

Plantings of mixed native species (termed 'environmental plantings') are increasingly being established for carbon sequestration whilst providing additional environmental benefits such as biodiversity and water quality. In Australia, they are currently one of the most common forms of reforestation. Investment in establishing and maintaining such plantings relies on having a cost-effective modelling approach to providing unbiased estimates of biomass production and carbon sequestration rates. In Australia, the Full Carbon Accounting Model (FullCAM) is used for both national greenhouse gas accounting and project-scale sequestration activities. Prior to undertaking the work presented here, the FullCAM tree growth curve was not calibrated specifically for environmental plantings and generally under-estimated their biomass. Here we collected and analysed above-ground biomass data from 605 mixed-species environmental plantings, and tested the effects of several planting characteristics on growth rates. Plantings were then categorised based on significant differences in growth rates. Growth of plantings differed between temperate and tropical regions. Tropical plantings were relatively uniform in terms of planting methods and their growth was largely related to stand age, consistent with the un-calibrated growth curve. However, in temperate regions where plantings were more variable, key factors influencing growth were planting width, stand density and species-mix (proportion of individuals that were trees). These categories provided the basis for FullCAM calibration. Although the overall model efficiency was only 39-46%, there was nonetheless no significant bias when the model was applied to the various planting categories. Thus, modelled estimates of biomass accumulation will be reliable on average, but estimates at any particular location will be uncertain, with either under- or over-prediction possible. When compared with the un-calibrated yield curves, predictions using the new calibrations show that early growth is likely to be more rapid and total above-ground biomass may be higher for many plantings at maturity. This study has considerably improved understanding of the patterns of growth in different types of environmental plantings, and in modelling biomass accumulation in young (<25. years old) plantings. However, significant challenges remain to understand longer-term stand dynamics, particularly with temporal changes in stand density and species composition. © 2014.

Le gyrus temporal supérieur est-il véritablement impliqué dans l'exagération des douleurs passées ?

Résumé : INTRODUCTION : Le rappel de douleurs passées est souvent inexact. Ce phénomène, connu sous le nom de biais mnémonique, pourrait être lié au développement de certaines douleurs chroniques. Dans une étude précédente, notre laboratoire a montré, grâce à l’électroencéphalographie, que l’activité du gyrus temporal supérieur (GTS) était positivement corrélée à l’exagération des rappels douloureux. L’objectif de cette étude était de confirmer si l’activité cérébrale du GTS est impliquée causalement dans le phénomène du biais mnémonique. MÉTHODES : Dans cette étude randomisée à double insu, la stimulation magnétique transcrânienne (TMS) fut utilisée pour perturber temporairement l’activité du GTS (paradigme de lésion virtuelle). Les participants étaient assignés aléatoirement au groupe contrôle (TMS simulée, n = 21) ou au groupe expérimental (TMS réelle, n = 21). L’intensité et l’aspect désagréable de la douleur ont été évalués grâce à des échelles visuelles analogues (ÉVA; 0 à 10) immédiatement après l’événement douloureux (stimulations électriques du nerf sural droit) et au rappel, 2 mois plus tard. L’exactitude du rappel douloureux fut calculée en soustrayant l’ÉVA au rappel de l’ÉVA initiale. RÉSULTATS : Le biais mnémonique de l’intensité de la douleur était similaire dans les deux groupes (contrôle = -0,3, expérimental = 0,0; p = 0,83) alors que le biais mnémonique de l’aspect désagréable de la douleur était significativement inférieur dans le groupe expérimental (contrôle = 1.0, expérimental = -0,4; p < 0,05). CONCLUSION : Nos résultats suggèrent que le GTS affecte spécifiquement nos souvenirs liés à l’aspect motivo-affectif de la douleur. Étant donné le lien entre l’exagération des souvenirs douloureux et la persistance de la douleur, l’inhibition du GTS pourrait être une avenue intéressante pour prévenir le développement de douleur chronique.

Improved models for estimating temporal changes in carbon sequestration in above-ground biomass of mixed-species environmental plantings

Plantings of mixed native species (termed 'environmental plantings') are increasingly being established for carbon sequestration whilst providing additional environmental benefits such as biodiversity and water quality. In Australia, they are currently one of the most common forms of reforestation. Investment in establishing and maintaining such plantings relies on having a cost-effective modelling approach to providing unbiased estimates of biomass production and carbon sequestration rates. In Australia, the Full Carbon Accounting Model (FullCAM) is used for both national greenhouse gas accounting and project-scale sequestration activities. Prior to undertaking the work presented here, the FullCAM tree growth curve was not calibrated specifically for environmental plantings and generally under-estimated their biomass. Here we collected and analysed above-ground biomass data from 605 mixed-species environmental plantings, and tested the effects of several planting characteristics on growth rates. Plantings were then categorised based on significant differences in growth rates. Growth of plantings differed between temperate and tropical regions. Tropical plantings were relatively uniform in terms of planting methods and their growth was largely related to stand age, consistent with the un-calibrated growth curve. However, in temperate regions where plantings were more variable, key factors influencing growth were planting width, stand density and species-mix (proportion of individuals that were trees). These categories provided the basis for FullCAM calibration. Although the overall model efficiency was only 39-46%, there was nonetheless no significant bias when the model was applied to the various planting categories. Thus, modelled estimates of biomass accumulation will be reliable on average, but estimates at any particular location will be uncertain, with either under- or over-prediction possible. When compared with the un-calibrated yield curves, predictions using the new calibrations show that early growth is likely to be more rapid and total above-ground biomass may be higher for many plantings at maturity. This study has considerably improved understanding of the patterns of growth in different types of environmental plantings, and in modelling biomass accumulation in young (<25 years old) plantings. However, significant challenges remain to understand longer-term stand dynamics, particularly with temporal changes in stand density and species composition.

Correcting for bias when estimating the cost of hospital-acquired infection : an analysis of lower respiratory tract infections in non-surgical patients

Hospital acquired infections (HAI) are costly but many are avoidable. Evaluating prevention programmes requires data on their costs and benefits. Estimating the actual costs of HAI (a measure of the cost savings due to prevention) is difficult as HAI changes cost by extending patient length of stay, yet, length of stay is a major risk factor for HAI. This endogeneity bias can confound attempts to measure accurately the cost of HAI. We propose a two-stage instrumental variables estimation strategy that explicitly controls for the endogeneity between risk of HAI and length of stay. We find that a 10% reduction in ex ante risk of HAI results in an expected savings of £693 ($US 984).