Involvement of AMPA receptor GluR2 subunits in stimulus reward learning: evidence from glutamate receptor gria 2 knockout mice.

Presence of the glutamate receptor 2 (GluR2) subunit prevents calcium influx through AMPA-receptor complexes; deletion of this subunit results in enhanced hippocampal long-term potentiation. We investigated whether mice lacking the GluR2 subunit [gria2 knock-out (KO) mice] displayed impairments in learning stimulus-reward associations, and the subsequent ability of reward-paired cues to control motivated behavior. Both gria2 KO and wild-type (WT) mice learned to associate a light/tone stimulus with food delivery, as evidenced by approach toward the food magazine after the presentation of the cues (pavlovian conditioning). Subsequently, the cues also served to reinforce an operant response in both KO and WT mice (conditioned reinforcement), although response rates were greater in gria2 KOs. Responding for conditioned reinforcement was enhanced after 0.5 mg/kg amphetamine administration in WT mice, but not in KO mice. The ability of the cues to elicit approach behavior (conditioned approach) and to enhance responding for the reward (pavlovian-to-instrumental transfer; PIT) were also impaired in gria2 KO mice. This pattern of behavior resembles that seen after lesions of the central nucleus of the amygdala (CeA), an area rich in GluR2-containing AMPA receptors. Immunostaining revealed reduced GluR1 expression within both the basolateral amygdala and the CeA, suggesting that the behavioral deficits observed were unlikely to be caused by compensatory changes in GluR1. These results suggest that GluR2-containing AMPA receptors, possibly within the CeA, are critical for the formation of stimulus-reward associations necessary for PIT and conditioned approach, but are not involved in the plastic processes underlying the attribution of motivational value to the conditioned stimulus (CS)

Selective disruption of stimulus-reward learning in glutamate receptor gria 1 knockout mice.

Glutamatergic neurotransmission via AMPA receptors has been an important focus of studies investigating neuronal plasticity. AMPA receptor glutamate receptor 1 (GluR1) subunits play a critical role in long-term potentiation (LTP). Because LTP is thought to be the cellular substrate for learning, we investigated whether mice lacking the GluR1 subunit [gria1 knock-outs (KO)] were capable of learning a simple cue-reward association, and whether such cues were able to influence motivated behavior. Both gria1 KO and wild-type mice learned to associate a light/tone stimulus with food delivery, as evidenced by their approaching the reward after presentation of the cue. During subsequent testing phases, gria1 KO mice also displayed normal approach to the cue in the absence of the reward (Pavlovian approach) and normal enhanced responding for the reward during cue presentations (Pavlovian to instrumental transfer). However, the cue did not act as a reward for learning a new behavior in the KO mice (conditioned reinforcement). This pattern of behavior is similar to that seen with lesions of the basolateral nucleus of the amygdala (BLA), and correspondingly, gria1 KO mice displayed impaired acquisition of responding under a second-order schedule. Thus, mice lacking the GluR1 receptor displayed a specific deficit in conditioned reward, suggesting that GluR1-containing AMPA receptors are important in the synaptic plasticity in the BLA that underlies conditioned reinforcement. Immunostaining for GluR2/3 subunits revealed changes in GluR2/3 expression in the gria1 KOs in the BLA but not the central nucleus of the amygdala (CA), consistent with the behavioral correlates of BLA but not CA function

Investigating the effects of inter-annual weather variation (1968- 2016) on the functional response of cereal grain yield to applied nitrogen, using data from the Rothamsted Long-Term experiments

The effect of weather on inter-annual variation in the crop yield response to nitrogen (N) fertilizer for winter wheat (Triticum aestivvum L.) and spring barley (Hordeum vulgare L.) was investigated using yield data from the Broadbalk Wheat and Hoosfield Spring Barley long-term experiments at Rothamsted Research. Grain yields of crops from 1968 to 2016 were modelled as a function of N rates using a linear-plus-exponential (LEXP) function. The extent to which inter-annual variation in the parameters of these responses was explained by variations in weather (monthly summarized temperatures and rainfall), and by changes in the cultivar grown, was assessed. The inter-annual variability in rainfall and underlying temperature influenced the crop N response and hence grain yields in both crops. Asymptotic yields in wheat were particularly sensitive to mean temperature in November, April and May, and to total rainfall in October, February and June. In spring barley asymptotic yields were sensitive to mean temperature in February and June, and to total rainfall in April to July inclusive and September. The method presented here explores the separation of agronomic and environmental (weather) influences on crop yield over time. Fitting N response curves across multiple treatments can support an informative analysis of the influence of weather variation on the yield variability. Whilst there are issues of the confounding and collinearity of explanatory variables within such models, and that other factors also influence yields over time, our study confirms the considerable impact of weather variables at certain times of the year. This emphasizes the importance of including weather temporal variation when evaluating the impacts of climate change on crops

Changes of oxygen isotope values of soil P pools associated with changes in soil pH

Field data about the effect of soil pH on phosphorus (P) cycling is limited. A promising tool to study P cycling under field conditions is the 18O:16O ratio of phosphate (δ18OP). In this study we investigate whether the δ18OP can be used to elucidate the effect of soil pH on P cycling in grasslands. Soils and plants were sampled from different fertilisation and lime treatments of the Park Grass long term experiment at Rothamsted Research, UK. The soils were sequentially extracted to isolate different soil P pools, including available P and corresponding δ18OP values were determined. We did not observe changes in plant δ18OP value, but soil P δ18OP values changed, and lower δ18OP values were associated with higher soil pH values. At sites where P was not limiting, available P δ18OP increased by up to 3‰ when lime was applied. We show that the δ18OP method is a useful tool to investigate the effect of pH on soil P cycling under field conditions as it highlights that different soil processes must govern P availability as pH shifts. The next challenge is now to identify these underlying processes, enabling better management of soil P at different pH

Single Pilot Workload Management During Cruise in Entry Level Jets

Advanced technologies and automation are important facilitators of single pilot operations, but they also contribute to the workload management challenges faced by the pilot. We examined task completion, workload management, and automation use in an entry level jet (ELJ) flown by single pilots. Thirteen certificated Cessna Citation Mustang (C510-S) pilots flew an instrument flight rules (IFR) experimental flight in a Cessna Citation Mustang simulator. At one point participants had to descend to meet a crossing restriction prior to a waypoint and prepare for an instrument approach into an un-towered field while facilitating communication from a lost pilot who was flying too low for ATC to hear. Four participants experienced some sort of difficulty with regard to meeting the crossing restriction and almost half (n=6) had problems associated with the instrument approach. Additional errors were also observed including eight participants landing at the airport with an incorrect altimeter setting

Single-Pilot Workload Management

Integrated glass cockpit systems place a heavy cognitive load on pilots (Burian Dismukes, 2007). Researchers from the NASA Ames Flight Cognition Lab and the FAA Flight Deck Human Factors Lab examined task and workload management by single pilots. This poster describes pilot performance regarding programming a reroute while at cruise and meeting a waypoint crossing restriction on the initial descent

The impact of weather and increased atmospheric CO2 from 1892 to 2016 on simulated yields of UK wheat

Climate change effects on UK winter wheat grain yield are complex: warmer temperature, negative; greater carbon dioxide (CO2) concentration, positive; but other environmental variables and their timing also affect yield. In the absence of long-term experiments where temperature and CO2 concentration were manipulated separately, we applied the crop simulation model Sirius with long-term daily meteorological data (1892-2016) for Rothamsted, Hertfordshire, UK (2007-2016 mean growing season temperature 1.03°C warmer than 1892-1991), and CO2 concentration over this period, to investigate the separate effects of historic CO2 and weather on simulated grain yield in three wheat cultivars of the modern era. We show a slight decline in simulated yield over the period 1892-2016 from the effect of weather (daily temperature, rainfall, and sunshine hours) at fixed CO2 (294.50 ppm, 1892 reference value), but a maximum 9.4% increase when accounting for increasing atmospheric CO2 (from 294.50 to 404.21 ppm), differing slightly amongst cultivars. Notwithstanding considerable inter-annual variation, the slight yield decline at 294.50 ppm CO2 over this 125-year period from the historic weather simulations for Rothamsted agrees with the expected decline from temperature increase alone, but the positive yield trend with actual CO2 values does not match the recent stagnation in UK wheat yield

Il naturalismo culturale di Dewey

The essay focuses on John Dewey’s pragmatic naturalism in order to show that the relatively recent naturalizing trend in philosophy should be considered a historically and culturally situated restriction of other forms of naturalism. Dewey’s cultural naturalism is based on a strong continuity between nature and culture, assuming that human intelligent behaviour arises from already existing organic and environmental resources in an entirely contingent manner. This kind of naturalism does not involve physical reductionism: more complex interactions between organisms and their environment, such as human mental behaviour, are seen as innovative, in the sense that they produce forms of organization that, on the one hand, are not reducible to the simple association of pre-existing elements. On the other hand, innovative modes of interaction between human organisms and their naturally social environment have consequence on the natural world: they produce changes within it. The second part of the text presents Dewey’s non-substantive conception of the mind, which has its roots in the non-reversible consequences of the advent of highly communicative and linguistic interactions in the human world as well as in the possibility for human organism to reconsider analytically or reflectively their primarily holistic, qualitatively felt experiences.The essay focuses on John Dewey’s pragmatic naturalism in order to show that the relatively recent naturalizing trend in philosophy should be considered a historically and culturally situated restriction of other forms of naturalism. Dewey’s cultural naturalism is based on a strong continuity between nature and culture, assuming that human intelligent behaviour arises from already existing organic and environmental resources in an entirely contingent manner. This kind of naturalism does not involve physical reductionism: more complex interactions between organisms and their environment, such as human mental behaviour, are seen as innovative, in the sense that they produce forms of organization that, on the one hand, are not reducible to the simple association of pre-existing elements. On the other hand, innovative modes of interaction between human organisms and their naturally social environment have consequence on the natural world: they produce changes within it. The second part of the text presents Dewey’s non-substantive conception of the mind, which has its roots in the non-reversible consequences of the advent of highly communicative and linguistic interactions in the human world as well as in the possibility for human organism to reconsider analytically or reflectively their primarily holistic, qualitatively felt experiences

Telomerecat: A ploidy-agnostic method for estimating telomere length from whole genome sequencing data.

Telomere length is a risk factor in disease and the dynamics of telomere length are crucial to our understanding of cell replication and vitality. The proliferation of whole genome sequencing represents an unprecedented opportunity to glean new insights into telomere biology on a previously unimaginable scale. To this end, a number of approaches for estimating telomere length from whole-genome sequencing data have been proposed. Here we present Telomerecat, a novel approach to the estimation of telomere length. Previous methods have been dependent on the number of telomeres present in a cell being known, which may be problematic when analysing aneuploid cancer data and non-human samples. Telomerecat is designed to be agnostic to the number of telomeres present, making it suited for the purpose of estimating telomere length in cancer studies. Telomerecat also accounts for interstitial telomeric reads and presents a novel approach to dealing with sequencing errors. We show that Telomerecat performs well at telomere length estimation when compared to leading experimental and computational methods. Furthermore, we show that it detects expected patterns in longitudinal data, repeated measurements, and cross-species comparisons. We also apply the method to a cancer cell data, uncovering an interesting relationship with the underlying telomerase genotype