The fate of redundant cues: Further analysis of the redundancy effect

Pearce, Dopson, Haselgrove, and Esber (Journal of Experimental Psychology: Animal Behavior Processes, 38, 167–179, 2012) conducted a series of experiments with rats and pigeons in which the conditioned responding elicited by two types of redundant cue was compared. One of these redundant cues was a blocked cue X from A+ AX+ training, whereas the other was cue Y from a simple discrimination BY+ CY–. Greater conditioned responding was elicited by X than by Y; we refer to this difference as the redundancy effect. To test an explanation of this effect in terms of comparator theory (Denniston, Savastano, & Miller, 2001), a single group of rats in Experiment 1 received training of the form A+ AX+ BY+ CY–, followed by an A– Y+ discrimination. Responding to the individual cues was tested both before and after the latter discrimination. In addition to a replication of the redundancy effect during the earlier test, we observed stronger responding to B than to X, both during the earlier test and, in contradiction of the theory, after the A– Y+ discrimination. In Experiment 2, a blocking group received A+ AX+, a continuous group received AX+ BX–, and a partial group received AX± BX± training. Subsequent tests with X again demonstrated the redundancy effect, but also revealed a stronger response in the partial than in the continuous group. This pattern of results is difficult to explain with error-correction theories that assume that stimuli compete for associative strength during conditioning. We suggest, instead, that the influence of a redundant cue is determined by its relationship with the event with which it is paired, and by the attention it is paid

Motility-induced phase separation mediated by bacterial quorum sensing

We study motility-induced phase separation (MIPS) in living active matter, in which cells interact through chemical signalling, or quorum sensing. In contrast to previous theories of MIPS, our multiscale continuum model accounts explicitly for genetic regulation of signal production and motility. Through analysis and simulations, we derive a new criterion for the onset of MIPS that depends on features of the genetic network. Furthermore, we identify and characterise a new type of oscillatory instability that occurs when gene regulation inside cells promotes motility in higher signal concentrations

Diversity and temperature indirectly reduce CO2 concentrations in experimental freshwater communities.

Biodiversity loss and climate warming are occurring in concert, with potentially profound impacts on ecosystem functioning. We currently know very little about the combined effects of these changes on the links between the community structure, dynamics and the resulting in situ CO2 concentrations in freshwater ecosystems. Here we aimed to determine both individual and combined effects of temperature and non-resource diversity (species inedible for a given consumer) on CO2 concentration. Our analysis further aimed to establish both direct effects on CO2 concentrations and potential indirect effects that occur via changes to the phytoplankton and zooplankton biomasses. Our results showed that there were no interactive effects of changes in temperature and diversity on CO2 concentration in the water. Instead, independent increases in either temperature or non-resource diversity resulted in a substantial reduction in CO2 concentrations, particularly at the highest non-resource diversity. The effects of non-resource diversity and warming on CO2 were indirect, resulting largely from the positive impacts on total biomass of primary producers. Our study is the first to experimentally partition the impacts of temperature and diversity on the consumer-resource dynamics and associated changes to CO2 concentrations. It provides new mechanistic insights into the role of diverse plankton communities for ecosystem functioning and their importance in regulating CO2 dynamics under ongoing climate warming

Effect of electronic adherence monitoring on adherence and outcomes in chronic conditions: A systematic review and metaanalysis

Introduction Electronic adherence monitoring (EAM) is increasingly used to improve adherence. However, there is limited evidence on the effect of EAM in across chronic conditions and on patient acceptability. We aimed to assess the effect of EAM on adherence and clinical outcomes, across all ages and all chronic conditions, and examine acceptability in this systematic review and meta-analysis. Methods A systematic search of Ovid MEDLINE, EMBASE, Social Work Abstracts, PsycINFO, International Pharmaceutical Abstracts and CINAHL databases was performed from database inception to December 31, 2020. Randomised controlled trials (RCTs) that evaluated the effect of EAM on medication adherence as part of an adherence intervention in chronic conditions were included. Study characteristics, differences in adherence and clinical outcomes between intervention and control were extracted from each study. Estimates were pooled using random-effects meta-analysis, and presented as mean differences, standardised mean differences (SMD) or risk ratios depending on the data. Differences by study-level characteristics were estimated using subgroup meta-analysis to identify intervention characteristics associated with improved adherence. Effects on adherence and clinical outcomes which could not be meta-analysed, and patient acceptability, were synthesised narratively. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline was followed, and Risk of bias (RoB) assessed using the Cochrane Collaboration's RoB tool for RCTs. The review is registered with PROSPERO CRD42017084231. Findings Our search identified 365 studies, of which 47 studies involving 6194 patients were included. Data from 27 studies (n = 2584) were extracted for the adherence outcome. The intervention group (n = 1267) had significantly better adherence compared to control (n = 1317), (SMD = 0.93, CI:0.69 to 1.17, p<0.0001) with high heterogeneity across studies (I2 = 86%). There was a significant difference in effect according to intervention complexity (p = 0.01); EAM only improved adherence when used with a reminder and/or health provider support. Clinical outcomes were measured in 38/47 (81%) of studies; of these data from 14 studies were included in a meta-analysis of clinical outcomes for HIV, hypertension and asthma. In total, 13/47 (28%) studies assessed acceptability; patient perceptions were mixed. Interpretation Patients receiving an EAM intervention had significantly better adherence than those who did not, but improved adherence did not consistently translate into clinical benefits. Acceptability data were mixed. Further research measuring effects on clinical outcomes and patient acceptability are needed

Open labware: 3-D printing your own lab equipment

The introduction of affordable, consumer-oriented 3-D printers is a milestone in the current “maker movement,” which has been heralded as the next industrial revolution. Combined with free and open sharing of detailed design blueprints and accessible development tools, rapid prototypes of complex products can now be assembled in one’s own garage—a game-changer reminiscent of the early days of personal computing. At the same time, 3-D printing has also allowed the scientific and engineering community to build the “little things” that help a lab get up and running much faster and easier than ever before

Rats distinguish between absence of events and lack of evidence in contingency learning.

The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred

An X-ray magnetic circular dichroism (XMCD) study of Fe ordering in a synthetic MgAl<inf>2</inf>O<inf>4</inf>-Fe<inf>3</inf>O<inf>4</inf> (spinel-magnetite) solid-solution series: Implications for magnetic properties and cation site ordering

© 2016 by Walter de Gruyter Berlin/Boston. Fe L2,3-edge XAS and XMCD studies have been used to unravel structural trends in the MgAl2O4-Fe3O4 solid solution where thermodynamic modeling has presented a challenge due to the complex ordering arrangements of the end-members. Partitioning of Fe3+ and Fe2+ between tetrahedral (Td) and octahedral (Oh) sites has been established. In the most Fe-rich samples, despite rapid quenching from a disordered state, FeTd2+ is not present, which matches the ordered, inverse spinel nature of end-member magnetite (Mgt) at room temperature. However, in intermediate compositions Al and Mg substantially replace Fe and small amounts of FeTd2+ are found, stabilized, or trapped by decreasing occurrence of the continuous nearest neighbor Fe-Fe interactions that facilitate charge redistribution by electron transfer. Furthermore, in the composition range ~Mgt0.4-0.9, XAS and XMCD bonding and site occupancy data suggest that nanoscale, magnetite-like Fe clusters are present. By contrast, at the spinel-rich end of the series, Mgt0.17 and Mgt0.23 have a homogeneous long-range distribution of Fe, Mg, and Al. These relationships are consistent with the intermediate and Fe-rich samples falling within a wide solvus in this system such that the Fe-clusters occur as proto-nuclei for phases that would exsolve following development of long-range crystalline order during slow cooling. Unit-cell edges calculated from the spectroscopy-derived site occupancies show excellent agreement with those measured by X-ray powder diffraction on the bulk samples. Calculated saturation magnetic moments (Ms) for the Fe-rich samples also show excellent agreement with measured values but for the most Mg-rich samples are displaced to slightly higher values; this displacement is due to the presence of abundant Mg and Al disrupting the anti-parallel alignment of electron spins for Fe atoms.We thank Richard Pattrick and Vicky Coker for help in collecting XMCD on these samples at the Daresbury SRS and subsequently at the Advanced Light Source (ALS), Berkeley. The ALS is supported by the Director, Office of Science, Office of Basic Energy Sciences (OBES) of the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231 and we thank Elke Arenholz for her assistance. RJH acknowledges funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 320750. KMR gratefully acknowledges support from the DOE OBES Chemical Sciences, Geosciences, and Biosciences Division, through the Geosciences Program at Pacific Northwest National Laboratory. We also thank Gerrit van der Laan and Nick Telling for help with XMCD data analysis; David Plant carried out the electron microprobe analyses at Manchester and Paul Schofield provided information on the natural magnesian spinel. We also thank two anonymous referees for constructive comments

Spin and Statistics and First Principles

It was shown in the early Seventies that, in Local Quantum Theory (that is the most general formulation of Quantum Field Theory, if we leave out only the unknown scenario of Quantum Gravity) the notion of Statistics can be grounded solely on the local observable quantities (without assuming neither the commutation relations nor even the existence of unobservable charged field operators); one finds that only the well known (para)statistics of Bose/Fermi type are allowed by the key principle of local commutativity of observables. In this frame it was possible to formulate and prove the Spin and Statistics Theorem purely on the basis of First Principles. In a subsequent stage it has been possible to prove the existence of a unique, canonical algebra of local field operators obeying ordinary Bose/Fermi commutation relations at spacelike separations. In this general guise the Spin - Statistics Theorem applies to Theories (on the four dimensional Minkowski space) where only massive particles with finite mass degeneracy can occur. Here we describe the underlying simple basic ideas, and briefly mention the subsequent generalisations; eventually we comment on the possible validity of the Spin - Statistics Theorem in presence of massless particles, or of violations of locality as expected in Quantum Gravity.Comment: Survey based on a talk given at the Meeting on "Theoretical and experimental aspects of the spin - statistics connection and related symmetries", Trieste, Italy - October 21-25, 200