Research on the Flow Parameters of Waste Motion in a Rotary Kiln with the Use of the Tracer Method.

The motion of input material in a rotary kiln is an important aspect of its operation. This can be observed especially in the case of the implementation of the hazardous waste incineration process in this device. The values of the flow parameters, mainly the residence time and the degree of mixing, can determine the proper and safe treatment of waste. The relationships that occur in the layer of solid material in a rotary kiln have not been completely recognized. This article presents a research method that involves an experiment on a laboratory stand simulating a rotary kiln in association with a dedicated algorithm. Multi-criteria tests were carried out. The adopted research method was the tracer method. It used a tracer which, subject to the same transport conditions as other material particles, provided information on the characteristic of the motion of tested materials in the rotating cylinder. The application based on the residence time distribution (RTD) algorithm returned information about the characteristics of the motion of the material in the rotary cylinder in terms of residence time distribution and the degree of mixing. This tracer method, together with stimulus impulses on the grate and a dedicated RTD algorithm, was used here as a sensor method to examine the characteristics of material motion on various grate systems. The data obtained as a result of this research may include, among others, the boundary conditions for numerical simulations of processes carried out in a rotary kiln.

Disentangling phylogenetic relations and biogeographic history within the Cucujus haematodes species group (Coleoptera: Cucujidae).

Recent progress in the taxonomy of flat bark beetles (Cucujidae), specifically, in the genus Cucujus, has revealed great diversity in subtropical Asia, but the seemingly well-known temperate and boreal taxa need further attention because of their conservation status. Here, we used an integrative approach using morphology, DNA, and species distribution modelling to disentangle phylogenetic relations, verify the number of species, and understand the historical biogeography of Palearctic and Nearctic Cucujus beetles, particularly the C. haematodes species group. Species distinctiveness was supported for C. cinnaberinus, but present-day C. haematodes turned out to be a species complex made up of separate lineages in the western, middle and eastern parts of its Palearctic range. Cucujus muelleri was a member of that complex, being sister to Asian C. haematodes. Moreover, C. haematodes caucasicus was found to be phylogenetically closely related to Italian C. tulliae, and both to be sister to European C. haematodes. North American C. clavipes clavipes and C. c. puniceus resulted to be enough divergent to be considered different species. Interestingly, western American C. puniceus turned out to be closely related to the C. haematodes complex, whereas eastern American C. clavipes constituted a separate lineage, being distantly related to both C. puniceus and C. cinnaberinus. These patterns suggest former trans-continental connections among the ancestors of extant flat bark beetle species. Moreover, a divergent lineage of C. cinnaberinus was found in Calabria, which should be regarded at the very least as a subspecies. The ancestor of C. hameatodes group originated in mid-Miocene, and next, ca. 6.2 Mya, a line leading to C. cinnaberinus had split. Speciation of the American lineages occurred during Pliocene (4.4 Mya for C. clavipes and 3.3 Mya for C. puniceus). Species classified as C. haematodes, C. tulliae and C. muelleri, as well as distinct lineages within C. cinnaberinus split during mid Pleistocene (ca. 1.5 Mya). A comparison of species climatic requirements and their present distribution allowed to identify glacial refugia in south-eastern areas of North America (C. clavipes), south-western areas of North America (C. puniceus), and the Mediterranean and Caspian Sea Basins (European Cucujus species), or south-eastern areas of Asia and the foothills of the central Asian mountains (eastern C. haematodes). Subsequent climatic changes in the Holocene forced these beetles to move their ranges northwards along the coasts of the Pacific (C. puniceus) or Atlantic (C. clavipes), north-eastwards to central, northern, and eastern Europe (C. cinnaberinus and European C. haematodes) or Siberia (Asian C. haematodes). The combined use of molecular, morphological and climatic data allows a comprehensive understanding of the phylogenetic relations and past distributions of Cucujus beetles, highlighting the complexity of C. haematodes species group evolution.

Arthropod dark taxa provide new insights into diversity responses to bark beetle infestations.

Natural disturbances are increasing around the globe, also impacting protected areas. Although previous studies have indicated that natural disturbances result in mainly positive effects on biodiversity, these analyses mostly focused on a few well established taxonomic groups, and thus uncertainty remains regarding the comprehensive impact of natural disturbances on biodiversity. Using Malaise traps and meta-barcoding, we studied a broad range of arthropod taxa, including dark and cryptic taxa, along a gradient of bark beetle disturbance severities in five European national parks. We identified order-level community thresholds of disturbance severity and classified barcode index numbers (BINs; a cluster system for DNA sequences, where each cluster corresponds to a species) as negative or positive disturbance indicators. Negative indicator BINs decreased above thresholds of low to medium disturbance severity (20%-30% of trees killed), whereas positive indicator BINs benefited from high disturbance severity (76%-98%). BINs allocated to a species name contained nearly as many positive as negative disturbance indicators, but dark and cryptic taxa, particularly Diptera and Hymenoptera in our data, contained higher numbers of negative disturbance indicator BINs. Analyses of changes in the richness of BINs showed variable responses of arthropods to disturbance severity at lower taxonomic levels, whereas no significant signal was detected at the order level due to the compensatory responses of the underlying taxa. We conclude that the analyses of dark taxa can offer new insights into biodiversity responses to disturbances. Our results suggest considerable potential for forest management to foster arthropod diversity, for example by maintaining both closed-canopy forests (>70% cover) and open forests (<30% cover) on the landscape.

The Large-Scale Physical Model Tests of the Passing Ship Effect on a Ship Moored at the Solid-Type Berth.

The paper presents experimental research on hydrodynamic forces generated on a ship moored at a long quay wall, modeling the solid-type berth, by a passing ship. The proper prediction of interactions between the moored and passing ships is important for design and operational purposes. The results of the presented parametric study are presented as a space-time series of the forces as the functions of passing ship velocity and transverse separation distance between the ships. The experimental test setup constructed on the lake and the large scale of the manned physical ship models enabled a simulation of the real maneuvering situation. The force measurements were taken on the moored ship model fixed to the pantographs rigidly attached to the wall. The twin pantographs were attached to force sensors on the deck of the model by a system of movable joints, enabling the measurement of surge and sway forces. The presented method was verified based on available experimental and numerical data, showing a good agreement with the results.

Optimization and Security of Hazardous Waste Incineration Plants with the Use of a Heuristic Algorithm.

The amount of generated waste, which increases every year, is a serious problem of the modern world. In particular, attention should be paid to hazardous waste and methods of its disposal. One of the most used in this context is thermal treatment in dedicated incinerators equipped with a rotary kiln. Conducting the process requires, inter alia, supplying the furnace with a batch of batch material with appropriate parameters. Improper operation in this regard may cause negative environmental effects and operational problems. The key here is to select different types of hazardous waste and compose batch portions. The paper presents an application that optimizes the work of waste incineration plant operators. At the same time, this tool can be described as ensuring security at this stage of the process. The application implements an ant colony algorithm that selects the optimal solution to the problem, which has been formulated here as the types and masses of the batch mixture components with given parameters. The application has been tested in the laboratory and real conditions with satisfactory results.

Boosting Intelligent Data Analysis in Smart Sensors by Integrating Knowledge and Machine Learning.

The presented paper proposes a hybrid neural architecture that enables intelligent data analysis efficacy to be boosted in smart sensor devices, which are typically resource-constrained and application-specific. The postulated concept integrates prior knowledge with learning from examples, thus allowing sensor devices to be used for the successful execution of machine learning even when the volume of training data is highly limited, using compact underlying hardware. The proposed architecture comprises two interacting functional modules arranged in a homogeneous, multiple-layer architecture. The first module, referred to as the knowledge sub-network, implements knowledge in the Conjunctive Normal Form through a three-layer structure composed of novel types of learnable units, called L-neurons. In contrast, the second module is a fully-connected conventional three-layer, feed-forward neural network, and it is referred to as a conventional neural sub-network. We show that the proposed hybrid structure successfully combines knowledge and learning, providing high recognition performance even for very limited training datasets, while also benefiting from an abundance of data, as it occurs for purely neural structures. In addition, since the proposed L-neurons can learn (through classical backpropagation), we show that the architecture is also capable of repairing its knowledge.

Interactive Timeline Approach for Contextual Spatio-Temporal ECT Data Investigation.

This paper presents a novel approach to a complex process of electrical capacitance tomography (ECT) measurement data analysis. ECT is frequently employed for non-invasive monitoring of industrial process phenomena. Proposed methodology is based on the premeditated integration of the spatial and temporal relations inherent in the measurement records into the workflow of the analysis procedure. We propose a concept of interactive timeline that enables arranging data visualization according to the user's current focus along the process of analysis. We evaluated the proposed method using a prototype system in a task-based user study conducted with a group of domain experts. The evaluation is based on gravitational silo flow measurement datasets. Proposed prototype system enables diverse data manipulation in a more natural way allowing the user to switch back and forth between space and time domains along the data analysis trail. Experiments with the prototype system showed that the accuracy and completion times have significantly improved in comparison to the performance measured in the baseline condition. Additionally, the participants reported decreased physical load with improved efficiency measured with NASA task load index. Finally, a short discussion coupled with directions for the future of interactive spatio-temporal ECT measurement data analysis conclude the paper.

GSK-3ß at the Intersection of Neuronal Plasticity and Neurodegeneration.

In neurons, Glycogen Synthase Kinase-3ß (GSK-3ß) has been shown to regulate various critical processes underlying structural and functional synaptic plasticity. Mouse models with neuron-selective expression or deletion of GSK-3ß present behavioral and cognitive abnormalities, positioning this protein kinase as a key signaling molecule in normal brain functioning. Furthermore, mouse models with defective GSK-3ß activity display distinct structural and behavioral abnormalities, which model some aspects of different neurological and neuropsychiatric disorders. Equalizing GSK-3ß activity in these mouse models by genetic or pharmacological interventions is able to rescue some of these abnormalities. Thus, GSK-3ß is a relevant therapeutic target for the treatment of many brain disorders. Here, we provide an overview of how GSK-3ß is regulated in physiological synaptic plasticity and how aberrant GSK-3ß activity contributes to the development of dysfunctional synaptic plasticity in neuropsychiatric and neurodegenerative disorders.

GSK-3α/ß kinases and amyloid production in vivo.

Arising from C. J. Phiel, C. A. Wilson, V. M.-Y. Lee & P. S. Klein 423, 435-439 (2003)A major unresolved issue in Alzheimer's disease is identifying the mechanisms that regulate proteolytic processing of amyloid precursor protein (APP)-glycogen synthase kinase-3 (GSK-3) isozymes are thought to be important in this regulation. Phiel et al. proposed that GSK-3α, but not GSK-3ß, controls production of amyloid. We analysed the proteolytic processing of mouse and human APP in mouse brain in vivo in five different genetic and viral models. Our data do not yield evidence for either GSK-3α-mediated or GSK-3ß-mediated control of APP processing in brain in vivo.

Fractalkine activates NRF2/NFE2L2 and heme oxygenase 1 to restrain tauopathy-induced microgliosis.

The chemokine fractalkine modulates microglial responses in neurodegenerative diseases, including tauopathies, but the mechanistic processes and their relevance in human brain pathologies is not yet known. Here, we show that hippocampal HT22 cells expressing human TAU(P301L) mutant protein produce fractalkine, which in microglia activates AKT, inhibits glycogen synthase kinase-3ß and upregulates the transcription factor NRF2/NFE2L2 and its target genes including heme oxygenase 1. In a mouse model of tauopathy based on stereotaxic delivery in hippocampus of an adeno-associated viral vector for expression of TAU(P301L), we confirmed that tau-injured neurons express fractalkine. NRF2- and fractalkine receptor-knockout mice did not express heme oxygenase 1 in microglia and exhibited increased microgliosis and astrogliosis in response to neuronal TAU(P301L) expression, demonstrating a crucial role of the fractalkine/NRF2/heme oxygenase 1 pathway in attenuation of the pro-inflammatory phenotype. The hippocampus of patients with Alzheimer's disease also exhibits increased expression of fractalkine in TAU-injured neurons that recruit microglia. These events correlated with increased levels of NRF2 and heme oxygenase 1 proteins, suggesting an attempt of the diseased brain to limit microgliosis. Our combined results indicate that fractalkine mobilizes NRF2 to limit over-activation of microglia and identify this new target to control unremitting neuroinflammation in tauopathies.

Terminal hypothermic Tau.P301L mice have increased Tau phosphorylation independently of glycogen synthase kinase 3α/ß.

The microtubule-associated protein Tau is responsible for a large group of neurodegenerative disorders, known as tauopathies, including Alzheimer's disease. Tauopathy result from augmented and/or aberrant phosphorylation of Tau. Besides aging and various genetic and epigenetic defects that remain largely unknown, an important non-genetic agent that contributes is hypothermia, eventually caused by anesthesia. Remarkably, tauopathy in brains of hibernating mammals is not pathogenic, and, because it is fully reversible, is even considered to be neuroprotective. Here, we assessed the terminal phase of Tau.P301L mice and bigenic crosses with mice lacking glycogen synthase kinase 3 (GSK3)α completely, or GSK3ß specifically in neurons. We also analysed biGT bigenic mice that co-express Tau.P301L with GSK3ß.S9A and develop severe forebrain tauopathy with age. We found that the precocious mortality of Tau.P301L mice was typified by hypothermia that aggravated Tau phosphorylation, but, surprisingly, independently of GSK3α/ß. The important contribution of hypothermia at the time of death of mice with tauopathy suggests that body temperature should be included as a parameter in the analysis of pre-clinical models, and, by extension, in patients suffering from tauopathy.

Medical Nutrition Therapy in Critically Ill Patients with COVID-19-A Single-Center Observational Study.

Medical nutrition should be tailored to cover a patient's needs, taking into account medical and organizational possibilities and obstacles. This observational study aimed to assess calories and protein delivery in critically ill patients with COVID-19. The study group comprised 72 subjects hospitalized in the intensive care unit (ICU) during the second and third SARS-CoV-2 waves in Poland. The caloric demand was calculated using the Harris-Benedict equation (HB), the Mifflin-St Jeor equation (MsJ), and the formula recommended by the European Society for Clinical Nutrition and Metabolism (ESPEN). Protein demand was calculated using ESPEN guidelines. Total daily calorie and protein intakes were collected during the first week of the ICU stay. The median coverages of the basal metabolic rate (BMR) during day 4 and day 7 of the ICU stay reached: 72% and 69% (HB), 74% and 76% (MsJ), and 73% and 71% (ESPEN), respectively. The median fulfillment of recommended protein intake was 40% on day 4 and 43% on day 7. The type of respiratory support influenced nutrition delivery. A need for ventilation in the prone position was the main difficulty to guarantee proper nutritional support. Systemic organizational improvement is needed to fulfill nutritional recommendations in this clinical scenario.

Hepatic Encephalopathy Confirmed by Magnetic Resonance Imaging in a Patient with Unobvious Cause of Chronic Liver Disease Decompensation.

Fifty-four-year old male was admitted to the intensive care unit (ICU) due to impaired consciousness. Past medical history included alcohol dependence, liver cirrhosis, esophageal varices, 2 esophageal varices banding procedures in the past, pathological obesity. Computed tomography (CT) examination of the head performed in the referring hospital was normal. At admission the CT examination of the head was repeated and showed no abnormalities. Urgent esophagogastroduodenoscopy revealed presence of esophageal varices and scarification following previous banding procedures located in the middle and lower part of the esophagus. Gastrointestinal bleeding being the most likely cause of chronic liver decompensation was therefore excluded. Multimodal neurologic diagnostic assessment was negative. Finally magnetic resonance imaging (MRI) of the head was performed. Taking into account clinical picture and the MRI result, the differential diagnosis included chronic liver encephalopathy, exacerbated acquired hepatocerebral degeneration, and acute liver encephalopathy. Due to history of umbilical hernia CT of the abdomen and pelvis was performed and showed intussusception of the ileum, confirming hepatic encephalopathy. In this case report the MRI suggested the diagnosis of hepatic encephalopathy and prompted search for alternative causes of decompensation of chronic liver disease.

Dendritic degeneration, neurovascular defects, and inflammation precede neuronal loss in a mouse model for tau-mediated neurodegeneration.

Adeno-associated virus (AAV)-mediated expression of wild-type or mutant P301L protein tau produces massive degeneration of pyramidal neurons without protein tau aggregation. We probed this novel model for genetic and structural factors and early parameters of pyramidal neurodegeneration. In yellow fluorescent protein-expressing transgenic mice, intracerebral injection of AAV-tauP301L revealed early damage to apical dendrites of CA1 pyramidal neurons, whereas their somata remained normal. Ultrastructurally, more and enlarged autophagic vacuoles were contained in degenerating dendrites and manifested as dark, discontinuous, vacuolated processes surrounded by activated astrocytes. Dendritic spines were lost in AAV-tauP301L-injected yellow fluorescent protein-expressing transgenic mice, and ultrastructurally, spines appeared dark and degenerating. In CX3CR1(EGFP/EGFP)-deficient mice, microglia were recruited early to neurons expressing human tau. The inflammatory response was accompanied by extravasation of plasma immunoglobulins. α2-Macroglobulin, but neither albumin nor transferrin, became lodged in the brain parenchyma. Large proteins, but not Evans blue, entered the brain of mice injected with AAV-tauP301L. Ultrastructurally, brain capillaries were constricted and surrounded by swollen astrocytes with extensions that contacted degenerating dendrites and axons. Together, these data corroborate the hypothesis that neuroinflammation participates essentially in tau-mediated neurodegeneration, and the model recapitulates early dendritic defects reminiscent of "dendritic amputation" in Alzheimer's disease.

Early synaptic deficits in GSK-3ß overexpressing mice.

Synaptic dysfunction is the prominent feature of many neuropsychiatric and neurological diseases, in which glycogen synthase kinase 3ß (GSK-3ß) has been shown to play a role. Overexpression of constitutively active form of GSK-3ß (GSK-3ß[S9A]) in mice recapitulates the cognitive and structural brain deficits characteristic for manic phase of bipolar disorder (BD). Yet, the mechanisms underlying GSK-3ß-induced synaptic dysfunction have not been fully elucidated. The aim of the present study was to dissect the effect of GSK-3ß overactivity on synaptic function in adolescent (3-week-old) mice. We found that overactivity of GSK-3ß in adolescent transgenic mice leads to an alteration in dendritic spines morphology of granule cells in dentate gyrus (DG) without changes in overall spine density. There was an increase in the number of thin, presumably immature dendritic spines in GSK-3ß[S9A] mice. Subsequent electrophysiological analysis showed changes in excitatory synaptic transmission manifested by an increase of inter-event intervals of miniature excitatory postsynaptic currents (mEPSCs) in DG granule cells and an increase in the number of silent (unfunctional) synapses at the perforant path-DG pathway in GSK-3ß[S9A] mice. Altogether, our data indicate that GSK-3ß overactivity leads to synaptic deficits in adolescent, GSK-3ß[S9A] mice. These data might provide potential mechanisms underlying GSK-3ß-induced synaptic dysfunction in psychiatric disorders.

The Effect of Trap Color on Catches of Monochamus galloprovincialis and Three Most Numerous Non-Target Insect Species.

Black pheromone-baited traps are commonly used for monitoring Monochamus galloprovincialis, a vector of Bursaphelenchus xylophilus, although few studies have been conducted on its response to color (black, white, and clear). The objective of our studies was to evaluate the attractiveness of different colors to M. galloprovincialis and non-target species: Spondylis buprestoides and predatory Thanasimus formicarius and T. femoralis. Laboratory tests of fifteen colors against immature and mature M. galloprovincialis revealed some differences in their color preference. In two field tests, eight colors of coroplast vanes in cross-vane traps were compared with unpainted white (a reference (RF)). The first test confirmed the laboratory results, i.e., RF was slightly more attractive to M. galloprovincialis than pastel yellow, reseda green, and cyan blue, but trap color had no significant effect on any of the insect species studied. In the second test, the attractiveness of RF was highest and significantly different from pure white (for all four species), light blue, and pine green (except S. buprestoides). Overall, the unpainted white traps appeared to be most effective in catching M. galloprovincialis. Thanasimus spp. responded to the colors similarly to M. galloprovincialis; therefore, either trap design or lure composition should be modified to reduce their catches.

Dysregulation of miRNAs Levels in Glycogen Synthase Kinase-3ß Overexpressing Mice and the Role of miR-221-5p in Synaptic Function.

Glycogen synthase kinase-3ß (GSK-3ß) is a highly expressed kinase in the brain, where it has an important role in synaptic plasticity. Aberrant activity of GSK-3ß leads to synaptic dysfunction which results in the development of several neuropsychiatric and neurological diseases. Notably, overexpression of constitutively active form of GSK-3ß (GSK-3ß[S9A]) in mice recapitulates the cognitive and structural defects characteristic for neurological and psychiatric disorders. However, the mechanisms by which GSK-3ß regulates synaptic functions are not clearly known. Here, we investigate the effects of GSK-3ß overactivity on neuronal miRNA expression in the mouse hippocampus. We found that GSK-3ß overactivity downregulates miRNA network with a potent effect on miR-221-5p (miR-221*). Next, characterization of miR-221* function in primary hippocampal cell culture transfected by miR-221* inhibitor, showed no structural changes in dendritic spine shape and density. Using electrophysiological methods, we found that downregulation of miR-221* increases excitatory synaptic transmission in hippocampal neurons, probably via postsynaptic mechanisms. Thus, our data reveal potential mechanism by which GSK-3ß and miRNAs might regulate synaptic function and therefore also synaptic plasticity.

Alzheimer's disease: old problem, new views from transgenic and viral models.

Alzheimer's dementia is developing ever more as a complex syndrome with various unknown genetic and epigenetic contributions. These are compounded on and exacerbating the underlying amyloid and tau pathology that remain the basis of the pathological definition of Alzheimer's disease. Here, we present a selection of aspects of recent bigenic and virus-based mouse strains, developed as pre-clinical models for Alzheimer's disease. We discuss newer features in the context of the characteristics defined in previously validated transgenic models. We focus on specific aspects of single and multiple transgenic mouse models for Alzheimer's disease and for tauopathies, rather than providing an exhaustive list of all available models. We concentrate on the content of information related to neurodegeneration and disease mechanisms. We pay attention to aspects and defects that are predicted by the models and can be tested in humans. We discuss implications that help translate the fundamental knowledge into clinical, diagnostic and therapeutic applications. We elaborate on the increasing knowledge extracted from transgenic models and from newer adeno-associated viral models. We advocate this combination as a valuable strategy to study molecular, cellular and system-related pathogenic mechanisms in AD and tauopathies. We believe that innovative animal models remain needed to critically test current views, to identify and validate therapeutic targets, to allow testing of compounds, to help understand and eventually treat tauopathies, including Alzheimer's disease.

Importance of meteorological and land use parameters for insect diversity in agricultural landscapes.

Human-induced climate and land-use changes are important factors influencing global insect diversity. Nevertheless, the influence of weather on biodiversity is still relatively rarely studied. Grassland insects may be the taxon that is most affected by changing weather. We focused on the influence of weather and land-use management on butterflies in hayed meadows in the Czech Republic. During two consecutive years (2019-2020), we studied nearly 300 independent meadows. The abundance of butterflies was more influenced by the weather than their species richness. We observed positive and mainly linear effects of increasing vegetation temperatures. One very influential variable was the light intensity, which had a nonlinear effect that promoted butterflies under direct sunlight. The humidity had mainly moderate, nonlinear effects. Surprisingly, the wind had only a small effect. We observed important effects of the flowering intensity and vegetation height on the butterfly species richness and abundance regarding land use. Marginal woody vegetation cover had a positive effect on the butterfly abundance, and management had little effect. We concluded that weather and land use had important effects on butterflies. Based on our research, we recommended the reconsideration of scientific studies and monitoring programs for insects concerning the temperature threshold (≥ 25 °C) and the consideration of light intensity as an important factor. Applying a detailed approach to measuring the flowering intensity is likely unnecessary, while meadow land-use parameters appear to be necessary for insect populations.

Distinct circuits in rat central amygdala for defensive behaviors evoked by socially signaled imminent versus remote danger.

Animals display a rich repertoire of defensive responses adequate to the threat proximity. In social species, these reactions can be additionally influenced by the behavior of fearful conspecifics. However, the majority of neuroscientific studies on socially triggered defensive responses focuses on one type of behavior, freezing. To study a broader range of socially triggered reactions and underlying mechanisms, we directly compared two experimental paradigms, mimicking occurrence of the imminent versus remote threat. Observation of a partner currently experiencing aversive stimulation evokes passive defensive responses in the observer rats. Similar interaction with a partner that has just undergone the aversive stimulation prompts animals to increase active exploration. Although the observers display behaviors similar to those of the aversively stimulated demonstrators, their reactions are not synchronized in time, suggesting that observers' responses are caused by the change in their affective state rather than mimicry. Using opsins targeted to behaviorally activated neurons, we tagged central amygdala (CeA) cells implicated in observers' responses to either imminent or remote threat and reactivated them during the exploration of a novel environment. The manipulation revealed that the two populations of CeA cells promote passive or active defensive responses, respectively. Further experiments confirmed that the two populations of cells at least partially differ in expression of molecular markers (protein kinase C-δ [PKC-δ] and corticotropin-releasing factor [CRF]) and connectivity patterns (receiving input from the basolateral amygdala or from the anterior insula). The results are consistent with the literature on single subjects' fear conditioning, suggesting that similar neuronal circuits control defensive responses in social and non-social contexts.