Integration of history information Drives Serial Dependence and Stabilizes Working Memory Representations.

Serial dependence has shown seemingly contradictory effects on visual perception and working memory. While serial dependence promotes perpetual and mnemonic stability, it biases behavioral reports toward prior information. The neural mechanisms that drive both biasing and adaptive stabilizing effects are not well understood. We proposed and tested a reactivation and integration mechanism that can account for these contradictory effects. We used multivariate pattern analyses of EEG data (26 human participants, 17 females, 9 males) to examine the reactivation of prior reported orientation during the delay period of a visual working memory task. The reactivation strength of prior reports, but not prior sensory items, was predictive of the magnitude of serial dependency biases. These reactivated representations integrated with the representation of the current memory item and improved the ability to decode the current contents of memory. Overall, our data provide convergent evidence suggesting that prior reports in a visual working memory task are reactivated on the subsequent trial and become integrated with current memory representations. This similarity-dependent reactivation mechanism drives both report biasing and stabilization effects attributed to serial dependence in working memory.

DLTKcat: deep learning-based prediction of temperature-dependent enzyme turnover rates.

The enzyme turnover rate, ${k}_{cat}$, quantifies enzyme kinetics by indicating the maximum efficiency of enzyme catalysis. Despite its importance, ${k}_{cat}$ values remain scarce in databases for most organisms, primarily because of the cost of experimental measurements. To predict ${k}_{cat}$ and account for its strong temperature dependence, DLTKcat was developed in this study and demonstrated superior performance (log10-scale root mean squared error = 0.88, R-squared = 0.66) than previously published models. Through two case studies, DLTKcat showed its ability to predict the effects of protein sequence mutations and temperature changes on ${k}_{cat}$ values. Although its quantitative accuracy is not high enough yet to model the responses of cellular metabolism to temperature changes, DLTKcat has the potential to eventually become a computational tool to describe the temperature dependence of biological systems.

State-dependent effects of responsive neurostimulation depend on seizure localization.

Brain-responsive neurostimulation is firmly ensconced among treatment options for drug-resistant focal epilepsy, but over a quarter of patients treated with the RNS System do not experience meaningful seizure reduction. Initial titration of RNS therapy is typically similar for all patients, raising the possibility that treatment response might be enhanced by consideration of patient-specific variables. Indeed, small, single-center studies have yielded preliminary evidence that RNS System effectiveness depends on the brain state during which stimulation is applied. The generalizability of these findings remains unclear, however, and it is unknown whether state-dependent effects of responsive neurostimulation are also stratified by location of the seizure onset zone where stimulation is delivered. We aimed to determine whether state-dependent effects of the RNS System are evident in the large, diverse, multi-center cohort of RNS System clinical trial participants and to test whether these effects differ between mesiotemporal and neocortical epilepsies. Eighty-one of 256 patients who were treated with the RNS System across 31 centers during clinical trials met criteria for inclusion in this retrospective study. Risk states were defined in relation to phases of daily and multi-day cycles of interictal epileptiform activity that are thought to determine seizure likelihood. We found that the probabilities of risk state transitions depended on the stimulation parameter being changed, the starting seizure risk state, and the stimulated brain region. Changes in two commonly adjusted stimulation parameters, charge density and stimulation frequency, produced opposite effects on risk state transitions depending on seizure localization. Greater variance in acute risk state transitions was explained by state-dependent responsive neurostimulation for bipolar stimulation for neocortical epilepsies and for monopolar stimulation for mesiotemporal epilepsies. Variability in effectiveness of RNS System therapy across individuals may relate, at least partly, to the fact that current treatment paradigms do not account fully for fluctuations in brain states or locations of simulation sites. State-dependence of electrical brain stimulation may inform development of next-generation closed-loop devices that can detect changes in brain state and deliver adaptive, localization-specific patterns of stimulation to maximize therapeutic effects.

Size Dependent Specific Heat Capacity of PbSe Nanocrystals.

Specific heat capacity is one of the most fundamental thermodynamic properties of materials. In this work, we measured the specific heat capacity of PbSe nanocrystals with diameters ranging from 5 to 23 nm, and its value increases significantly from 0.2 to 0.6 J g-1 °C-1. We propose a mass assignment model to describe the specific heat capacity of nanocrystals, which divides it into four parts: electron, inner, surface, and ligand. By eliminating the contribution of ligand and electron specific heat capacity, the specific heat capacity of the inorganic core is linearly proportional to its surface-to-volume ratio, showing the size dependence. Based on this linear relationship, surface specific heat capacity accounts for 40-60% of the specific heat capacity of nanocrystals with size decreasing. It can be attributed to the uncoordinated surface atoms, which is evidenced by the appearance of extra surface phonons in Raman spectra and ab initio molecular dynamics (AIMD) simulations.

Manipulation of Macrophage Uptake by Controlling the Aspect Ratio of Graft Copolymer Micelles.

Nanostructures of drug carriers play a crucial role in nanomedicine due to their ability to influence drug delivery. There is yet no clear consensus regarding the optimal size and shape (e.g., aspect ratio) of nanoparticles for minimizing macrophage uptake, given the difficulties in controlling the shape and size of nanoparticles while maintaining identical surface properties. Here, we employed graft copolymer self-assembly to prepare polymer micelles with aspect ratios ranging from 1.0 (spherical) to 10.8 (cylindrical) and closely matched interfacial properties. Notably, our findings emphasize that cylindrical micelles with an aspect ratio of 2.4 are the least susceptible to macrophage uptake compared with both their longer counterparts and spherical micelles. This reduced uptake of the short cylindrical micelles results in a 3.3-fold increase in blood circulation time compared with their spherical counterparts. Controlling the aspect ratio of nanoparticles is crucial for improving drug delivery efficacy through better nanoparticle design.

Size Sensitivity of Metabolite Diffusion in Macromolecular Crowds.

Metabolites play crucial roles in cellular processes, yet their diffusion in the densely packed interiors of cells remains poorly understood, compounded by conflicting reports in existing studies. Here, we employ pulsed-gradient stimulated-echo NMR and Brownian/Stokesian dynamics simulations to elucidate the behavior of nano- and subnanometer-sized tracers in crowded environments. Using Ficoll as a crowder, we observe a linear decrease in tracer diffusivity with increasing occupied volume fraction, persisting─somewhat surprisingly─up to volume fractions of 30-40%. While simulations suggest a linear correlation between diffusivity slowdown and particle size, experimental findings hint at a more intricate relationship, possibly influenced by Ficoll's porosity. Simulations and numerical calculations of tracer diffusivity in the E. coli cytoplasm show a nonlinear yet monotonic diffusion slowdown with particle size. We discuss our results in the context of nanoviscosity and discrepancies with existing studies.

Organ dependency on fascia connective tissue.

Fascia is a specialized connective tissue system that encapsulates and interconnects between tissues and organs throughout the body. The fascia system regulates pain sensation, organ inflammation, trauma, and fibrotic diseases. This mini-review summarizes recent findings from animal models, which reveal the inter-dependency between tissues/organs and the fascia system. Special mechanisms are explored of fascia response to skin inflammatory processes and fibrotic microenvironments in trauma models. We highlight the functionally diverse communities of its fascia-born fibroblasts and the significance of their stage-specific differentiation and communication to disease progression. Understanding the molecular mechanisms and cellular processes within the fascia microenvironment may serve as a basis for future clinical translation.

Phenotype and predictors of insulin independence in adults presenting with diabetic ketoacidosis: a prospective cohort study.

AIMS/HYPOTHESIS: The aim of this work was to describe the phenotype of adults presenting with a first episode of diabetic ketoacidosis (DKA) in Cape Town, South Africa, and identify predictors of insulin independence at 12 and 60 months after presentation. METHODS: A prospective, descriptive cohort study of all individuals, 18 years or older, presenting for the first time with DKA to four public-sector hospitals of the Groote Schuur Academic Health Complex was performed. Clinical, biochemical and laboratory data including GAD antibody and C-peptide status were collected at baseline. Insulin was systematically weaned and stopped in individuals who achieved normoglycaemia within the months after DKA. Individuals were followed for 12 months and then annually until 5 years after initial presentation with ketoacidosis. RESULTS: Eighty-eight individuals newly diagnosed with diabetes when presenting with DKA were included and followed for 5 years. The mean ± SD age was 35±10 years and the median (IQR) BMI at diagnosis was 28.5 (23.3-33.4) kg/m2. Overall, 46% were insulin independent 12 months after diagnosis and 26% remained insulin independent 5 years after presentation. Forty-one participants (47%) tested negative for anti-GAD and anti-IA-2 antibodies and had C-peptide levels >0.3 nmol/l; in this group, 68% were insulin independent at 12 months and 37% at 5 years after diagnosis. The presence of acanthosis nigricans was strongly associated with insulin independence (OR 27.1 [95% CI 7.2, 102.2]; p<0.001); a positive antibody status was associated with a lower likelihood of insulin independence at 12 months (OR 0.10 [95% CI 0.03, 0.36]; p<0.001). On multivariable analysis only acanthosis (OR 11.5 [95% CI 2.5, 53.2]; p=0.004) was predictive of insulin independence 5 years after diagnosis. CONCLUSIONS/INTERPRETATION: The predominant phenotype of adults presenting with a first episode of DKA in Cape Town, South Africa, was that of ketosis-prone type 2 diabetes. These individuals presented with obesity, acanthosis nigricans, negative antibodies and normal C-peptide and could potentially be weaned off insulin at follow-up. Classic type 1 diabetes (lower weight, antibody positivity, low or unrecordable C-peptide levels and long-term insulin dependence) was less common. The simple clinical sign of acanthosis nigricans is a strong predictor of insulin independence at 12 months and 5 years after initial presentation.

Residual force depression is not related to positive muscle fascicle work during submaximal voluntary dorsiflexion contractions in humans.

Residual force depression (rFD) following active muscle shortening is assumed to correlate most strongly with muscle work, but this has not been tested during voluntary contractions in humans. Using dynamometry, we compared steady-state ankle joint torques (N = 16) following tibialis anterior (TA) muscle-tendon unit (MTU) lengthening and shortening to the time-matched torque during submaximal voluntary fixed-end dorsiflexion reference contractions (REF) at a matched MTU length and EMG amplitude. Ultrasound revealed significantly reduced (P < 0.001) TA fascicle shortening amplitudes during MTU lengthening without a preload over small and medium amplitudes, respectively, relative to REF. MTU lengthening with a preload over a large amplitude significantly (P < 0.001) increased fascicle shortening relative to REF, as well as stretch amplitudes relative to MTU lengthening without a preload (P = 0.001). Significant (P = 0.028) steady-state fascicle force enhancement relative to REF was observed following MTU lengthening, and was similar among MTU lengthening-hold conditions (3-5%). MTU shortening with and without a preload over small and large amplitudes significantly (P < 0.001) increased positive fascicle and MTU work relative to REF, but significant (P = 0.006) rFD was observed following MTU shortening with a preload (7-10%) only. rFD was linearly related to positive MTU work [rrm (47) = 0.48, P < 0.001], but not positive fascicle work [rrm (47) = 0.16, P = 0.277]. Our findings indicate that MTU lengthening without substantial fascicle stretch enhances steady-state force output, which might arise from less shortening-induced rFD. Our findings also indicate similar rFD following different amounts of positive fascicle/MTU work, which cautions against using work to predict rFD during submaximal voluntary contractions. KEY POINTS: Accurately predicting muscle force is challenging because active muscle shortening depresses force output. The residual force depression (rFD) that exists following active muscle shortening is commonly assumed to correlate strongly and positively with muscle work. We found that tibialis anterior muscle fascicle work and muscle-tendon unit work did not accurately predict rFD during submaximal voluntary dorsiflexion contractions. Fascicle shortening during fixed-end reference contractions also potentially induced rFD of 3-5%, which was similar to the rFD following muscle-tendon unit shortening without a preload. A higher number of active muscle fibres during shortening probably increased rFD, which suggests that motor unit recruitment during shortening might predict rFD.

Evolution of realized niche breadth diversity driven by community dynamics.

Why many herbivorous insects are host plant specialists, with non-negligible exceptions, is a conundrum of evolutionary biology, especially because the host plants are not necessarily optimal larval diets. Here, I present a novel model of host plant preference evolution of two insect species. Because habitat preference evolution is contingent upon demographic dynamics, I integrate the evolutionary framework with the modern coexistence theory. The results show that the two insect species can evolve into a habitat specialist and generalist, when they experience both negative and positive frequency-dependent community dynamics. This happens because the joint action of positive and negative frequency dependence creates multiple (up to nine) eco-evolutionary equilibria. Furthermore, initial condition dependence due to positive frequency dependence allows specialization to poor habitats. Thus, evolved habitat preferences do not necessarily correlate with the performances. The model provides explanations for counterintuitive empirical patterns and mechanistic interpretations for phenomenological models of niche breadth evolution.

Nerves and availability of mesodermal cells are essential for the function of the segment addition zone (SAZ) during segment regeneration in polychaete annelids.

Most of annelids grow all over their asexual life through the continuous addition of segments from a special zone called "segment addition zone" (SAZ) adjacent to the posterior extremity called pygidium. Amputation of posterior segments leads to regeneration (posterior regeneration-PR) of the pygidium and a new SAZ, as well as new segments issued from this new SAZ. Amputation of anterior segments leads some species to regeneration (anterior regeneration-AR) of the prostomium and a SAZ which produces new segments postero-anteriorly as during PR. During the 1960s and 1970s decades, experimental methods on different species (Syllidae, Nereidae, Aricidae) showed that the function of SAZ depends on the presence and number of mesodermal regeneration cells. Selective destruction of mesodermal regeneration cells in AR had no effect on the regeneration of the prostomium, but as for PR, it inhibited segment regeneration. Thus, worms deprived of mesodermal regeneration cells are always able to regenerate the pygidium or the prostomium, but they are unable to regenerate segments, a result which indicates that the SAZ functions only if these regeneration cells are present during PR or AR. Additionally, during AR, nerve fibres regenerate from the cut nerve cord toward the newformed brain, a situation which deprives the SAZ of local regenerating nerve fibres and their secreted growth factors. In contrast, during PR, nerve fibres regenerate both during the entire regeneration phase and then in normal growth. This review summarizes the experimental evidence for mesoderm cell involvement in segment regeneration, and the differential impact of the digestive tube and the regenerated nerve cord during PR vs AR.

An open label non-inferiority randomized controlled trial evaluated alternate day prednisolone given daily during infections vs. levamisole in frequently relapsing nephrotic syndrome.

Initial therapies for children with frequently relapsing nephrotic syndrome include alternate-day prednisolone that is given daily during infections, or levamisole. In this open label, non-inferiority trial, 160 patients, 2 to 18-years-old with frequent relapses, were randomly assigned to receive either prednisolone (0.5-0.7 mg/kg/alternate-day, given daily during infections), or levamisole (2-2.5 mg/kg/alternate-days) for one-year. Patients with relapses on alternate day prednisolone at over 1 mg/kg, prior use of potent steroid-sparing therapies, eGFR under 60 ml/min/1.73 m2 and significant steroid toxicity were excluded. Primary outcome was the proportion of patients with frequent relapses, defined as three-relapses in one-year, or two-relapses within six-months if associated with significant steroid toxicity or loss to follow up. Eighty patients each were randomized to receive prednisolone and levamisole. Baseline features showed preponderance of young patients presenting within two-years of disease onset. On intention-to-treat analysis, frequent relapses were more common in patients administered prednisolone (40% versus 22.5%; risk difference 17.5%; 95% confidence interval 3.4-31.6%). Prednisolone was not non-inferior to levamisole in preventing frequent relapses. However, the two groups showed similar proportions of patients in sustained remission, comparable frequency of relapses, and low frequency of adverse events. The decline in steroid requirement from baseline was higher in the levamisole group. Per-protocol analysis showed similar results. These results have implications for choice of therapy for frequently relapsing nephrotic syndrome. Although therapy with alternate-day prednisolone was not non-inferior to levamisole in preventing frequent relapses, both therapies were effective in other outcome measures. Thus, levamisole was relatively steroid-sparing and may be preferred in patients at risk of steroid toxicity.

Human brain dynamics dissociate early perceptual and late motor-related stages of affordance processing.

Affordances, the opportunities for action offered by the environment to an agent, are vital for meaningful behaviour and exist in every interaction with the environment. There is an ongoing debate in the field about whether the perception of affordances is an automated process. Some studies suggest that affordance perception is an automated process that is independent from the visual context and bodily interaction with the environment, whereas others argue that it is modulated by the visual and motor context in which affordances are perceived. The present paper aims to resolve this debate by examining affordance automaticity from the perspective of sensorimotor time windows. To investigate the impact of different forms of bodily interactions with an environment, that is, the movement context (physical vs. joystick movement), we replicated a previous study on affordance perception in which participants actively moved through differently wide doors in an immersive 3D virtual environment. In the present study, we displayed the same environment on a 2D screen with participants moving through doors of different widths using the keys on a standard keyboard. We compared components of the event-related potential (ERP) from the continuously recorded electroencephalogram (EEG) that were previously reported to be related to affordance perception of architectural transitions (passable and impassable doors). Comparing early sensory and later motor-related ERPs, our study replicated ERPs reflecting early affordance perception but found differences in later motor-related components. These results indicate a shift from automated perception of affordances during early sensorimotor time windows to movement context dependence of affordance perception at later stages, suggesting that affordance perception is a dynamic and flexible process that changes over sensorimotor stages.

Evaluation of a hospital-initiated tobacco dependence treatment service: uptake, smoking cessation, readmission and mortality.

BACKGROUND: The National Health Service in England aims to implement tobacco dependency treatment services in all hospitals by 2024. We aimed to assess the uptake of a new service, adapted from the Ottawa Model of Smoking Cessation, and its impact on 6-month quit rates and readmission or death at 1-year follow-up. METHODS: We conducted a pragmatic service evaluation of a tobacco dependency service implemented among 2067 patients who smoked who were admitted to 2 acute hospitals in London, England, over a 12-month period from July 2020. The intervention consisted of the systematic identification of smoking status, automatic referral to tobacco dependence specialists, provision of pharmacotherapy and behavioural support throughout the hospital stay, and telephone support for 6 months after discharge. The outcomes were (i) patient acceptance of the intervention during admission, (ii) quit success at 6 months after discharge, (iii) death, or (iv) readmission up to 1 year following discharge. Multivariable logistic regression was used to estimate the impact of a range of clinical and demographic variables on these outcomes. RESULTS: The majority (79.4%) of patients accepted support at the first assessment. Six months after discharge, 35.1% of successfully contacted patients reported having quit smoking. After adjustment, odds of accepting support were 51-61% higher among patients of all non-White ethnicity groups, relative to White patients, but patients of Mixed, Asian, or Other ethnicities had decreased odds of quit success (adjusted odds ratio (AOR) = 0.32, 95%CI = 0.15-0.66). Decreased odds of accepting support were associated with a diagnosis of cardiovascular disease or diabetes; however, diabetes was associated with increased odds of quit success (AOR = 1.88, 95%CI = 1.17-3.04). Intention to make a quit attempt was associated with a threefold increase in odds of quit success, and 60% lower odds of death, compared to patients who did not intend to quit. A mental health diagnosis was associated with an 84% increase in the odds of dying within 12 months. CONCLUSIONS: The overall quit rates were similar to results from Ottawa models implemented elsewhere, although outcomes varied by site. Outcomes also varied according to patient demographics and diagnoses, suggesting personalised and culturally tailored interventions may be needed to optimise quit success.

Clustering care pathways of people with alcohol dependence using a data linkage of routine data in Bremen, Germany.

BACKGROUND: Although many individuals with alcohol dependence (AD) are recognized in the German healthcare system, only a few utilize addiction-specific treatment services. Those who enter treatment are not well characterized regarding their prospective pathways through the highly fragmented German healthcare system. This paper aims to (1) identify typical care pathways of patients with AD and their adherence to treatment guidelines and (2) explore the characteristics of these patients using routine data from different healthcare sectors. METHODS: We linked routinely collected register data of individuals with a documented alcohol-related diagnosis in the federal state of Bremen, Germany, in 2016/2017 and their addiction-specific health care: two statutory health insurance funds (outpatient pharmacotherapy for relapse prevention and inpatient episodes due to AD with and without qualified withdrawal treatment (QWT)), the German Pension Insurance (rehabilitation treatment) and a group of communal hospitals (outpatient addiction care). Individual care pathways of five different daily states of utilized addiction-specific treatment following an index inpatient admission due to AD were analyzed using state sequence analysis and cluster analysis. The follow-up time was 307 days (10 months). Individuals of the clustered pathways were compared concerning current treatment recommendations (1: QWT followed by postacute treatment; 2: time between QWT and rehabilitation). Patients' characteristics not considered during the cluster analysis (sex, age, nationality, comorbidity, and outpatient addiction care) were then compared using a multinomial logistic regression. RESULTS: The analysis of 518 individual sequences resulted in the identification of four pathway clusters differing in their utilization of acute and postacute treatment. Most did not utilize subsequent addiction-specific treatment after their index inpatient episode (n = 276) or had several inpatient episodes or QWT without postacute treatment (n = 205). Two small clusters contained pathways either starting rehabilitation (n = 26) or pharmacotherapy after the index episode (n = 11). Overall, only 9.3% utilized postacute treatment as recommended. CONCLUSIONS: A concern besides the generally low utilization of addiction-specific treatment is the implementation of postacute treatments for individuals after QWT.

The effectiveness of a standardized tobacco cessation program on psychophysiological parameters in patients with addiction undergoing long-term rehabilitation: a quasi-experimental pilot study.

BACKGROUND: Although there is a very high comorbidity between tobacco dependence and other addictive disorders, there are only few studies examining the implementation and outcomes of a tobacco cessation program in patients with addictive diseases. Therefore, the aim of this study is to investigate to what extent a standardized tobacco cessation program leads to improvements regarding psychological/physical parameters in patients with addiction undergoing therapy and whether there is a reduction in tobacco consumption. METHODS: The study took place in a therapeutic community specialized in addiction therapy. A total sample of 56 participants were non-randomly assigned to an intervention group (IG; n = 31) and a treatment as usual group (TAUG; n = 25). The IG participated in a 6-week tobacco cessation program, while the TAUG received no additional treatment. Both groups were assessed for changes in primary outcomes (tobacco dependence, smoked cigarettes per day (CPD), and general substance-related craving) and secondary outcomes (heart rate variability (HRV): root mean square of successive differences, self-efficacy, and comorbid psychiatric symptoms) at two measurement time points (pre- and post-treatment/6 weeks). RESULTS: We observed significant improvements in self-efficacy (F(1,53) = 5.86; p < .05; ηp2 = .11) and decreased CPD in the IG (ß = 1.16, ρ < .05), while no significant changes were observed in the TAUG. No significant interaction effects were observed in psychiatric symptoms, general substance-related craving, and HRV. CONCLUSIONS: The results highlight the potential benefit of an additional tobacco cessation program as part of a general addiction treatment. Although no improvements in the physiological domain were observed, there were significant improvements regarding self-efficacy and CPD in the IG compared to the TAUG. Randomized controlled trials on larger samples would be an important next step. TRIAL REGISTRATION: ISRCTN15684371.

Space-Confined Growth of Ultrathin P-Type GeTe Nanosheets for Broadband Photodetectors.

As p-type phase-change degenerate semiconductors, crystalline and amorphous germanium telluride (GeTe) exhibit metallic and semiconducting properties, respectively. However, the massive structural defects and strong interface scattering in amorphous GeTe films significantly reduce their performance. In this work, two-dimensional (2D) p-type GeTe nanosheets are synthesized via a specially designed space-confined chemical vapor deposition (CVD) method, with the thickness of the GeTe nanosheets reduced to 1.9 nm. The space-confined CVD method improves the crystallinity of ultrathin GeTe by lowering the partial pressure of the reactant gas, resulting in GeTe nanosheets with excellent p-type semiconductor properties, such as a satisfactory on/off ratio of 105. Temperature-dependent electrical measurements demonstrate that variable-range hopping and optical-phonon-assisted hopping mechanisms dominate transport behavior at low and high temperatures, respectively. GeTe devices exhibit significantly high responsivity (6589 and 2.2 A W-1 at 633 and 980 nm, respectively) and detectivity (1.67 × 1011 and 1.3 × 108 Jones at 633 and 980 nm, respectively), making them feasible for broadband photodetectors in the visible to near-infrared range. Furthermore, the fabricated GeTe/WS2 diode exhibits a rectification ratio of 103 at zero gate voltage. These satisfactory p-type semiconductor properties demonstrate that ultrathin GeTe exhibits enormous potential for applications in optoelectronic interconnection circuits.

Visual continuum in non-human animals: serial dependence revealed in dogs.

Serial dependence is a recently described phenomenon by which the perceptual evaluation of a stimulus is biased by a previously attended one. By integrating stimuli over time, serial dependence is believed to ensure a stable conscious experience. Despite increasing studies in humans, it is unknown if the process occurs also in other species. Here, we assessed whether serial dependence occurs in dogs. To this aim, dogs were trained on a quantity discrimination task before being presented with a discrimination where one of the discriminanda was preceded by a task-irrelevant stimulus. If dogs are susceptible to serial dependence, the task-irrelevant stimulus was hypothesized to influence the perception of the subsequently presented quantity. Our results revealed that dogs perceived the currently presented quantity to be closer to the one presented briefly before, in accordance with serial dependence. The direction and strength of the effect were comparable to those observed in humans. Data regarding dogs' attention during the task suggest that dogs used two different quantity estimation mechanisms, an indication of a higher cognitive mechanism involved in the process. The present results are the first empirical evidence that serial dependence extends beyond humans, suggesting that the mechanism is shared by phylogenetically distant mammals.

Patterns and inferred causes of liana mortality in a tropical forest.

Lianas are major contributors to tropical forest dynamics, yet we know little about their mortality. Using overlapping censuses of the lianas and trees across a 50 ha stand of moist tropical forest, we contrasted community-wide patterns of liana mortality with relatively well-studied patterns of tree mortality to quantify patterns of liana death and identify contributing factors. Liana mortality rates were 172% higher than tree mortality rates, but species-level mortality rates of lianas were similar to trees with 'fast' life-history strategies and both growth forms exhibited similar spatial and size-dependent patterns. The mortality rates of liana saplings (<2.1 cm in diameter), which represent about 50% of liana individuals, decreased with increasing disturbance severity and remained consistently low during post-disturbance stand thinning. In contrast, larger liana individuals and trees of all sizes had elevated mortality rates in response to disturbance and their mortality rates decreased over time since disturbance. Within undisturbed forest patches, liana mortality rates increased with increasing soil fertility in a manner similar to trees. The distinct responses of liana saplings to disturbance appeared to distinguish liana mortality from that of trees, whereas similarities in their patterns of death suggest that there are common drivers of woody plant mortality.

The effects of eating a traditional high fat/high carbohydrate or a ketogenic diet on sensitivity of female rats to morphine.

Patients diagnosed with obesity are prescribed opioid medications at a higher rate than the general population; however, it is not known if eating a high fat diet might impact individual sensitivity to these medications. To explore the hypothesis that eating a high fat diet increases sensitivity of rats to the effects of morphine, 24 female Sprague-Dawley rats (n=8/diet) ate either a standard laboratory chow (17% kcal from fat), a high fat/low carbohydrate (ketogenic) chow (90.5% kcal from fat), or a traditional high fat/high carbohydrate chow (60% kcal from fat). Morphine-induced antinociception was assessed using a warm water tail withdrawal procedure, during which latency (in seconds) for rats to remove their tail from warm water baths was recorded following saline or morphine (0.32-56 mg/kg, IP) injections. Morphine was administered acutely and chronically, which involved 19 days of twice daily injections (increasing in 1/4 log dose increments every 3 days: 3.2-56 mg/kg, IP) to induce dependence and assess tolerance. The adverse effects of morphine (i.e., tolerance, withdrawal, changes in body temperature) were assessed throughout the study. Morphine induced comparable antinociception in rats eating different diets, and all rats developed tolerance following chronic morphine exposure. Additional adverse effects of morphine were also comparable among rats eating different diets; however, withdrawal-induced weight loss was less severe for rats eating ketogenic chow. These results suggest that dietary manipulation might modulate the severity of withdrawal-related weight loss, in ways that could be relevant for patients. Significance Statement The present study in female rats suggests that eating a high fat/low carbohydrate (ketogenic) or a traditional high fat/high carbohydrate diet does not impact the pain-relieving or adverse effects of opioids (i.e., tolerance or withdrawal). However, eating a ketogenic diet may have beneficial effects on opioid withdrawal-related weight loss. Individuals diagnosed with obesity taking opioids for pain-related conditions might therefore consider adopting a ketogenic diet when opioid administration is discontinued to potentially mitigate withdrawal-related weight loss.