A theoretical analysis of non-Markovian open system dynamics in correlated quantum materials

Gaining fine control over the behaviours of open quantum systems requires a finer understanding of the ways in which their environments impact their dynamics. While frequent approaches invoke Markovian approximations, the modern push towards picosecond quantum technologies highlights the practical need for treatments that go beyond this paradigm. In non-Markovian dynamical regimes, excitations within the environment of a system have lifetimes long enough to mediate a time-delayed self-coupling. These memory effects can lead to quantitatively distinct features in the resulting dynamics of the system, and so a precise understanding of their origin is crucial. Building upon a robust theoretical framework, we perform a systematic analysis of the dynamics of an impurity spin coupled to strongly correlated materials. As a theoretically and experimentally accessible model, we start with the Luttinger liquid, which allows us to study how strong correlations and interactions alter the response of the bath to the impurity and the resulting dynamics. Under this framework, non-Markovian behaviour emerges in the form of an initial slip prior to the spin decoherence, and we find that the signatures of spin-charge separation within the Luttinger liquid play a direct role in mediating this response. We further uncover the precise link between the strengths of interactions in modulating the rate and amplitude of this feature, which can be either greatly enhanced or suppressed. Equipped with this knowledge, we demonstrate that additional advantage can be gained out of cooling protocols that operate based on the non-Markovian dynamical response. We also consider scenarios where the massive Klein-Gordon model is an emergent theory of the bath, uncovering rich theoretical insights into the relationship between massive and massless limits via transient generalised Gibbs ensembles. Remarkably, we find that this transient regime is characterised by a massless theory with a mass-dependent effective temperature

Veterinarsko značenje komarčića roda Culicoides (Ceratopogonidae) u nekim podruèjima Saudijske Arabije.

Despite reports of severe outbreaks of arboviral diseases in domestic animals in Saudi Arabia, very little effort has been made to study the potential local vectors of these diseases. Diseases such as bluetongue and African horse sickness were reported in Saudi Arabia. Such diseases are internationally known to be vectored by Culicoides midges. The present study was undertaken at three localities in Saudi Arabia where arboviral activity had previously been reported. Results revealed the presence of four Culicoides species in the three localities. Two of these species were confirmed as vectors of arboviruses of domestic animals in neighbouring countries. The results were discussed in relation to the epidemiology of arboviral diseases in Saudi Arabia.Usprkos pojave teških arbovirusnih zaraza u domaćih životinja u Saudijskoj Arabiji, vrlo malo pozornosti posvećuje se istraživanjima mogućih vektora. U Saudijskoj Arabiji javljaju se bolesti kao što su bolest plavog jezika i konjska kuga. Poznato je da njih prenose komarčići roda Culicoides. Istraživanje je poduzeto na trima područjima u Saudijskoj Arabiji na kojima je već prethodno dokazana aktivnost arbovirusa. Dokazane su četiri vrste komarčića. Potvrđeno je da dvije od tih vrsta služe kao vektori arbovirusa u domaćih životinja. Rezultati su razmatrani u sklopu epizootiologije arbovirusnih bolesti u Saudijskoj Arabiji

Debris-Collecting Vacuum Machine with Grounded Safety System and Associated Methods

A debris collection machine includes a vacuum system (including a suction source operable to provide suction for pulling debris into a receptacle), a ground reference portion, a ground test portion, and a ground-checking module. The ground reference portion is electrically coupled with an electrically grounded reference point, and the ground test portion is electrically coupled with a portion of the vacuum system. The ground-checking module determines a resistance between from the ground reference portion and the ground test portion and prevents or terminates operation of the suction source of the vacuum system when the resistance exceeds a predetermined threshold value, e.g., which may correspond to a risk condition of spark generation that could ignite material in the receptacle

The Behavioral and Neural Mechanisms Underlying the Tracking of Expertise

Evaluating the abilities of others is fundamental for successful economic and social behavior. We investigated the computational and neurobiological basis of ability tracking by designing an fMRI task that required participants to use and update estimates of both people and algorithms’ expertise through observation of their predictions. Behaviorally, we find a model-based algorithm characterized subject predictions better than several alternative models. Notably, when the agent’s prediction was concordant rather than discordant with the subject’s own likely prediction, participants credited people more than algorithms for correct predictions and penalized them less for incorrect predictions. Neurally, many components of the mentalizing network—medial prefrontal cortex, anterior cingulate gyrus, temporoparietal junction, and precuneus—represented or updated expertise beliefs about both people and algorithms. Moreover, activity in lateral orbitofrontal and medial prefrontal cortex reflected behavioral differences in learning about people and algorithms. These findings provide basic insights into the neural basis of social learning

Low GABA concentrations in occipital cortex and anterior cingulate cortex in medication-free, recovered depressed patients

Studies using proton magnetic resonance spectroscopy (1H-MRS) indicate that unmedicated, acutely depressed patients have decreased levels of γ-aminobutyric acid (GABA) in the occipital cortex. The aim of this study was to use 1H-MRS to determine if changes in occipital and frontal cortical GABA levels were present in patients with a history of depression who had recovered and were no longer taking medication. We used 1H-MRS to measure levels of GABA in both occipital cortex and anterior cingulate cortex/prefrontal cortex in medication-free, fully recovered subjects with a history of recurrent unipolar depression. Levels of GABA in both occipital and anterior cingulate cortex were significantly lower in recovered depressed subjects than healthy controls. Our data provide preliminary evidence that a history of recurrent depression is associated with decreased GABA levels in anterior cingulate cortex and occipital cortex. These changes could represent part of the neurobiological vulnerability to recurrent depressive episodes

Scientific understanding of East African climate change from the HyCRISTAL project

Integrating Hydro-Climate Science into Policy Decisions for Climate-Resilient Infrastructure and Livelihoods in East Africa (HyCRISTAL) is a Future Climate for Africa (FCFA) project funded to deliver new understanding of East African climate change and its impacts, and to demonstrate use of climate change information in long-term decision-making in the region. Here, we briefly summarise key findings from HyCRISTAL so far on climate change, as well as key findings from the pan-African FCFA project “IMPALA” relevant to East Africa, both in the context of previous literature on the topic

Scientific understanding of East African climate change from the HyCRISTAL project

Integrating Hydro-Climate Science into Policy Decisions for Climate-Resilient Infrastructure and Livelihoods in East Africa (HyCRISTAL) is a Future Climate for Africa (FCFA) project funded to deliver new understanding of East African climate change and its impacts, and to demonstrate use of climate change information in long-term decision-making in the region. Here, we briefly summarise key findings from HyCRISTAL so far on climate change, as well as key findings from the pan-African FCFA project “IMPALA” relevant to East Africa, both in the context of previous literature on the topic

The Neural Representation of Prospective Choice during Spatial Planning and Decisions

We are remarkably adept at inferring the consequences of our actions, yet the neuronal mechanisms that allow us to plan a sequence of novel choices remain unclear. We used functional magnetic resonance imaging (fMRI) to investigate how the human brain plans the shortest path to a goal in novel mazes with one (shallow maze) or two (deep maze) choice points. We observed two distinct anterior prefrontal responses to demanding choices at the second choice point: one in rostrodorsal medial prefrontal cortex (rd-mPFC)/superior frontal gyrus (SFG) that was also sensitive to (deactivated by) demanding initial choices and another in lateral frontopolar cortex (lFPC), which was only engaged by demanding choices at the second choice point. Furthermore, we identified hippocampal responses during planning that correlated with subsequent choice accuracy and response time, particularly in mazes affording sequential choices. Psychophysiological interaction (PPI) analyses showed that coupling between the hippocampus and rd-mPFC increases during sequential (deep versus shallow) planning and is higher before correct versus incorrect choices. In short, using a naturalistic spatial planning paradigm, we reveal how the human brain represents sequential choices during planning without extensive training. Our data highlight a network centred on the cortical midline and hippocampus that allows us to make prospective choices while maintaining initial choices during planning in novel environments

Hydrological Outlook UK: an operational streamflow and groundwater level forecasting system at monthly to seasonal time scales

This paper describes the development of the first operational seasonal hydrological forecasting service for the UK, the Hydrological Outlook UK (HOUK). Since June 2013, this service has delivered monthly forecasts of streamflow and groundwater levels, with an emphasis on forecasting hydrological conditions over the next three months, accompanied by outlooks over longer time horizons. This system is based on three complementary approaches combined to produce the outlooks: (i) national-scale modelling of streamflow and groundwater levels based on dynamic seasonal rainfall forecasts, (ii) catchment-scale modelling where streamflow and groundwater level models are driven by historical meteorological forcings (i.e. the Ensemble Streamflow Prediction, ESP, approach), and (iii) a catchment-scale statistical method based on persistence and historical analogues. This paper provides the background to the Hydrological Outlook, describes the various component methods in detail and then considers the impact and usefulness of the product. As an example of a multi-method, operational seasonal hydrological forecasting system, it is hoped that this overview provides useful information and context for other forecasting initiatives around the world