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Accurate diagnosis of bipolar disorder (BPD) is difficult in clinical practice, with an average delay between symptom onset and diagnosis of about 7 years. A depressive episode often precedes the first manic episode, making it difficult to distinguish BPD from unipolar major depressive disorder (MDD).
Aims
We use genome-wide association analyses (GWAS) to identify differential genetic factors and to develop predictors based on polygenic risk scores (PRS) that may aid early differential diagnosis.
Method
Based on individual genotypes from case–control cohorts of BPD and MDD shared through the Psychiatric Genomics Consortium, we compile case–case–control cohorts, applying a careful quality control procedure. In a resulting cohort of 51 149 individuals (15 532 BPD patients, 12 920 MDD patients and 22 697 controls), we perform a variety of GWAS and PRS analyses.
Results
Although our GWAS is not well powered to identify genome-wide significant loci, we find significant chip heritability and demonstrate the ability of the resulting PRS to distinguish BPD from MDD, including BPD cases with depressive onset (BPD-D). We replicate our PRS findings in an independent Danish cohort (iPSYCH 2015, N = 25 966). We observe strong genetic correlation between our case–case GWAS and that of case–control BPD.
Conclusions
We find that MDD and BPD, including BPD-D are genetically distinct. Our findings support that controls, MDD and BPD patients primarily lie on a continuum of genetic risk. Future studies with larger and richer samples will likely yield a better understanding of these findings and enable the development of better genetic predictors distinguishing BPD and, importantly, BPD-D from MDD.
Antidepressants are commonly prescribed for mood disorders. Epidemiological studies suggest antidepressant use may be associated with cataracts and glaucoma. We aim to investigate the association between antidepressants and cataracts and glaucoma.
Methods
Data was collected from the United States Food and Drug Administration Adverse Event Reporting System. Reporting odds ratio (ROR) and Bayesian information components (IC025) were calculated for antidepressants (ie, selective serotonin reuptake inhibitors [SSRIs], selective norepinephrine reuptake inhibitors [SNRIs], serotonin-norepinephrine-dopamine reuptake inhibitors, serotonin modulators and stimulators, serotonin antagonists and reuptake inhibitors [SARIs], norepinephrine reuptake inhibitors, norepinephrine-dopamine reuptake inhibitors, tricyclic antidepressants [TCAs], tetracyclic antidepressants [TeCAs], and monoamine oxidase inhibitors [MAOIs]). The reference agent was acetaminophen.
Results
TeCAs and MAOIs were significantly associated with a decreased risk of cataracts (ROR = 0.11-0.65 and 0.16-0.69, respectively). TCAs, brexanolone, esketamine, and opipramol reported an increased cataract risk (ROR = 1.31-12.81). For glaucoma, SSRIs, SNRIs, SARIs, TCAs, MAOIs, and other investigated antidepressants reported significant RORs ranging from 1.034 to 21.17. There was a nonsignificant association of angle closure glaucoma (ACG) and open angle glaucoma (OAG) with the investigated antidepressants.
Limitations
For adverse event cases, multiple suspected product names are listed, and as cases are not routinely verified, there may be a possibility of duplicate reports and causality cannot be established.
Conclusion
Most of the investigated antidepressants were associated with a lower risk of cataract reporting. TCAs, brexanolone, esketamine, and opipramol were associated with greater odds of cataract. For most antidepressants, there was an insignificant increase in reports of ACG and OAG.
Recent guidance from UK health authorities strongly cautions against the use of valproic acid (VPA) in persons under 55 because of reevaluated risk of teratogenicity.
Objective
To summarize the extant literature documenting VPA-associated anatomical, behavioral, and cognitive teratogenicity.
Method
Pubmed, Medline, Cochrane Library, PsychInfo, Embase, Scopus, Web of Science, and Google Scholar were searched in accordance with PRISMA guidelines. Collected data covered study design, participant characteristics, anatomical, behavioral, or cognitive effects, and folic acid outcomes.
Results
122 studies were identified meeting inclusion comprised of studies evaluating anatomical (n = 67), behavioral (n = 28), and cognitive (n = 47) teratogenicity. Twenty studies were identified reporting on the risk mitigation effects of folic acid supplementation. Prenatal VPA exposure is associated with anatomical teratogenicity including major congenital malformations (odds ratio [OR] 2.47–9.30; p < 0.005). Behavioral teratogenicity including autism (OR 1.70–4.38), impaired motor development (OR 7.0), and ADHD (OR 1.39) are also significantly associated with VPA exposure. VPA was associated with intellectual disability and low IQ (hazard ratio [HR] 2.4–4.48, verbal intelligence: Spearman’s ρ = −0.436, respectively). Teratogenic effects were dose-dependent across all domains and were significant when compared with controls and other antiepileptic drugs (eg, carbamazepine, lamotrigine, and levetiracetam). Folic acid supplementation does not significantly reduce the hazard associated with VPA.
Conclusions
VPA is significantly associated with anatomical, behavioral, and cognitive teratogenicity. Folic acid supplementation does not abrogate the risk of teratogenicity associated with VPA exposure. Available evidence supports recommendations to reduce VPA exposure in women of reproductive age.
The World Health Organization (WHO) has defined Post-COVID-19 Condition (PCC) as the onset of symptoms within three months after resolution of an acute SARS-CoV-2 infection, wherein symptoms persist for at least two months and cannot be explained by another medical/psychiatric condition. Persons living with PCC report debilitating symptoms including, but not limited to, depressive symptoms and motivational deficits. The aim of this post-hoc analysis was to evaluate the association between depressive symptoms and motivation in adults with PCC.
Methods
We conducted a post-hoc analysis of an 8-week, double-blind, randomized, placebo-controlled trial evaluating adults (18 years or older) in Canada with WHO-defined PCC and cognitive symptoms. This post-hoc analysis is comprised of baseline data that evaluates the association between depressive symptom severity measured by the 16-item Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR-16) and motivational systems measured by the Behavioral Inhibition System/Behavioral Activation System Questionnaire (BIS/BAS).
Results
There was a statistically significant association between depressive symptoms and BIS (β = -0.041 95% CI [-0.066, -0.016], p<0.05), BAS reward responsiveness (β = 0.043 95% CI [0.012, 0.074], p<0.05), sex (β = -0.137 95% CI [-0.266, -0.008], p<0.05), and confirmed COVID-19 infection (β = 0.196 95% CI [0.061, 0.332], p<0.05).
Conclusions
Depressive symptoms were associated with motivational deficits in persons living with PCC. Optimizing treatment for depressive symptoms may potentially improve aspects of motivational impairment amongst persons with PCC. All patients presenting with MDD and a history of COVID-19 infection should be assessed for the presence of PCC.
In response to the COVID-19 pandemic, we rapidly implemented a plasma coordination center, within two months, to support transfusion for two outpatient randomized controlled trials. The center design was based on an investigational drug services model and a Food and Drug Administration-compliant database to manage blood product inventory and trial safety.
Methods:
A core investigational team adapted a cloud-based platform to randomize patient assignments and track inventory distribution of control plasma and high-titer COVID-19 convalescent plasma of different blood groups from 29 donor collection centers directly to blood banks serving 26 transfusion sites.
Results:
We performed 1,351 transfusions in 16 months. The transparency of the digital inventory at each site was critical to facilitate qualification, randomization, and overnight shipments of blood group-compatible plasma for transfusions into trial participants. While inventory challenges were heightened with COVID-19 convalescent plasma, the cloud-based system, and the flexible approach of the plasma coordination center staff across the blood bank network enabled decentralized procurement and distribution of investigational products to maintain inventory thresholds and overcome local supply chain restraints at the sites.
Conclusion:
The rapid creation of a plasma coordination center for outpatient transfusions is infrequent in the academic setting. Distributing more than 3,100 plasma units to blood banks charged with managing investigational inventory across the U.S. in a decentralized manner posed operational and regulatory challenges while providing opportunities for the plasma coordination center to contribute to research of global importance. This program can serve as a template in subsequent public health emergencies.
Creating a sustainable residency research program is necessary to develop a sustainable research pipeline, as highlighted by the recent Society for Academic Emergency Medicine 2024 Consensus Conference. We sought to describe the implementation of a novel, immersive research program for first-year emergency medicine residents. We describe the curriculum development, rationale, implementation process, and lessons learned from the implementation of a year-long research curriculum for first-year residents. We further evaluated resident perception of confidence in research methodology, interest in research, and the importance of their research experience through a 32-item survey. In two cohorts, 25 first-year residents completed the program. All residents met their scholarly project requirements by the end of their first year. Two conference abstracts and one peer-reviewed publication were accepted for publication, and one is currently under review. Survey responses indicated that there was an increase in residents’ perceived confidence in research methodology, but this was limited by the small sample size. In summary, this novel resident research curriculum demonstrated a standardized, reproducible, and sustainable approach to provide residents with an immersive research program.
Diagnostic criteria for major depressive disorder allow for heterogeneous symptom profiles but genetic analysis of major depressive symptoms has the potential to identify clinical and etiological subtypes. There are several challenges to integrating symptom data from genetically informative cohorts, such as sample size differences between clinical and community cohorts and various patterns of missing data.
Methods
We conducted genome-wide association studies of major depressive symptoms in three cohorts that were enriched for participants with a diagnosis of depression (Psychiatric Genomics Consortium, Australian Genetics of Depression Study, Generation Scotland) and three community cohorts who were not recruited on the basis of diagnosis (Avon Longitudinal Study of Parents and Children, Estonian Biobank, and UK Biobank). We fit a series of confirmatory factor models with factors that accounted for how symptom data was sampled and then compared alternative models with different symptom factors.
Results
The best fitting model had a distinct factor for Appetite/Weight symptoms and an additional measurement factor that accounted for the skip-structure in community cohorts (use of Depression and Anhedonia as gating symptoms).
Conclusion
The results show the importance of assessing the directionality of symptoms (such as hypersomnia versus insomnia) and of accounting for study and measurement design when meta-analyzing genetic association data.
Auditory verbal hallucinations (AVHs) in schizophrenia have been suggested to arise from failure of corollary discharge mechanisms to correctly predict and suppress self-initiated inner speech. However, it is unclear whether such dysfunction is related to motor preparation of inner speech during which sensorimotor predictions are formed. The contingent negative variation (CNV) is a slow-going negative event-related potential that occurs prior to executing an action. A recent meta-analysis has revealed a large effect for CNV blunting in schizophrenia. Given that inner speech, similar to overt speech, has been shown to be preceded by a CNV, the present study tested the notion that AVHs are associated with inner speech-specific motor preparation deficits.
Objectives
The present study aimed to provide a useful framework for directly testing the long-held idea that AVHs may be related to inner speech-specific CNV blunting in patients with schizophrenia. This may hold promise for a reliable biomarker of AVHs.
Methods
Hallucinating (n=52) and non-hallucinating (n=45) patients with schizophrenia, along with matched healthy controls (n=42), participated in a novel electroencephalographic (EEG) paradigm. In the Active condition, they were asked to imagine a single phoneme at a cue moment while, precisely at the same time, being presented with an auditory probe. In the Passive condition, they were asked to passively listen to the auditory probes. The amplitude of the CNV preceding the production of inner speech was examined.
Results
Healthy controls showed a larger CNV amplitude (p = .002, d = .50) in the Active compared to the Passive condition, replicating previous results of a CNV preceding inner speech. However, both patient groups did not show a difference between the two conditions (p > .05). Importantly, a repeated measure ANOVA revealed a significant interaction effect (p = .007, ηp2 = .05). Follow-up contrasts showed that healthy controls exhibited a larger CNV amplitude in the Active condition than both the hallucinating (p = .013, d = .52) and non-hallucinating patients (p < .001, d = .88). No difference was found between the two patient groups (p = .320, d = .20).
Conclusions
The results indicated that motor preparation of inner speech in schizophrenia was disrupted. While the production of inner speech resulted in a larger CNV than passive listening in healthy controls, which was indicative of the involvement of motor planning, patients exhibited markedly blunted motor preparatory activity to inner speech. This may reflect dysfunction in the formation of corollary discharges. Interestingly, the deficits did not differ between hallucinating and non-hallucinating patients. Future work is needed to elucidate the specificity of inner speech-specific motor preparation deficits with AVHs. Overall, this study provides evidence in support of atypical inner speech monitoring in schizophrenia.
The Korean Basketball League(KBL) holds an annual draft to allow teams to select new players, mostly graduates from the elite college basketball teams even though some are from high school teams. In sports games, many factors might influence the success of an athlete. In addition to possessing excellent physical and technical factors, success in a sports game is also influenced by remarkable psychological factors. Several studies reported that elite sports players can control their anxiety during competition, which may lead to better performance. In particular, the temperament and characteristics of players have been regarded as crucial determinants of the player’s performance and goal. In this regard, numerous studies suggest that personality is considered to be an important predictor of long-term success in professional sports
Objectives
Based on previous reports and studies, we hypothesized that physical status, temperament and characteristics, and neurocognitive functions of basketball players could predict the result of KBL draft selection. Especially, temperament and characteristics were associated with the result of KBL selection. The basketball performances including average scores and average rebound were associated with emotional perception and mental rotation.
Methods
We recruited the number of 44 college elite basketball players(KBL selection, n=17; Non-KBL selection, n=27), and the number of 35 age-matched healthy comparison subjects who major in sports education in college. All participants were assessed with the Temperament and Character Inventory(TCI), Sports Anxiety Scales(SAS), Beck Depression Inventory(BDI), Perceived Stress Scale (PSS-10), Trail Making Test(TMT), and Computerized Neuro-cognitive Test(CNT) for Emotional Perception and Mental Rotation.
Results
Current results showed that physical status, temperament and characteristics, and Neurocognitive functions of college basketball players could predict the KBL draft selection. Among temperament and characteristics, novelty seeking and reward dependence were associated with KBL draft selection. The basketball performances including average scores and average rebound were associated with emotional perception and mental rotation.
Conclusions
In order to be a good basketball player for a long time, it was confirmed that temperamental factors and Neurocognitive factors were very closely related. Furthermore, it is also judged that these results can be used as basic data to predict potential professional basketball players.
Palmer amaranth (Amaranthus palmeri S. Watson), a dioecious wind-pollinated plant, is one of the most troublesome crop weeds in the United States and is spreading northward. The prodigious production of seed contributes to establishment of populations and spread across the landscape. Sexual reproduction via outcrossing is likely the primary mode of seed production for this dioecious plant. However, A. palmeri may also be capable of autonomous asexual seed production (apomixis), which could be beneficial during colonization. We conducted two studies of female isolation from pollen to investigate the propensity for autonomous seed production in 19 populations across eastern North America. In the first, we observed low-frequency seed production on many isolated females. Using flow cytometry of seed samples (FCSS) we primarily found patterns of ploidy consistent with sexual reproduction; no significant differences in ploidy between seeds produced on isolated females (putative apomicts) and non-isolated females (putatively sexual) were detected. We also investigated patterns of DNA content and found no evidence in 153 samples for polyploidy, which is often observed in apomictic species. The second female isolation trial utilized sex-specific molecular markers to identify and remove males before flowering, and we observed zero seed production. Overall, we did not detect evidence in support of apomixis in these populations of A. palmeri, suggesting that apomixis is unlikely to have played a role in the northward advance of this species in eastern North America. We also investigated whether there is variation between females and males in size and secondary reproductive traits. We found evidence for sexual dimorphism in three of six traits investigated: females are taller at senescence and produce longer secondary branches and more axillary flowers than males. Differences in cost of reproduction and strategies for pollen release versus pollen capture are likely factors shaping the evolution of sexual dimorphism in this wind-pollinated dioecious plant.
This article examines ‘diasporic geopolitics’ as a significant factor in the future of global politics. Whereas discussions of global order in IR have been highly spatialised, we instead highlight the extent to which different regions of the world are entangled via ongoing migration processes, and their legacies in the form of global diasporas. We examine the significance of these interconnections by focusing on rising powers and their relations with the existing international order. Major migration-sending states such as China, India, and Turkey are now aspiring great powers that seek to exert global influence in international affairs. In this context, their diaspora governance policies are also undergoing a transformation, with diasporas increasingly understood as important assets for promoting sending states’ geopolitical agendas and great power ambitions. We examine three mechanisms by which such states exert power transnationally via their diaspora engagement policies. States can treat ‘their’ diasporas as economic assets that facilitate trade and foreign investment; as soft power assets that contribute to the promotion of ‘civilisational’ politics; and as diplomatic assets that can be strategically mobilised or repressed. We conclude by discussing the implications for thinking about the nature of global order and power politics in the coming 50 years.
Individuals who have recovered from the acute stage of SARS-CoV-2 infection may be at risk of developing post-COVID-19 condition (PCC), characterised by a spectrum of persisting, non-specific, and functionally impairing symptoms across multiple organ systems. Obesity has been implicated as a risk factor for PCC, mediated by chronic systemic inflammation. The foregoing has also been separately reported to mediate cognitive dysfunction in PCC.
Methods:
This is a post-hoc analysis of a randomised, double-blinded, placebo-controlled clinical trial evaluating vortioxetine treatment for cognitive impairments in persons with PCC who received vortioxetine or placebo for eight weeks. This analysis comprises baseline data, examining the impact of BMI on cognitive functioning measured by the Digit Symbol Substitution Test (DSST) and Trails Making Tests (TMT)-A/B, as well as inflammation, via serum c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).
Results:
Complete data from 70 participants were statistically analysed and adjusted for age and sex. BMI was negatively correlated with performance on the DSST (β = −0.003, p = 0.047), TMT-A (β = −0.006, p = 0.025), and TMT-B (β = −0.006, p = 0.002). BMI was positively correlated with serum CRP (unstandardized β = 0.193, standardized β = 0.612, p < 0.001) and ESR (β = 0.039, p < 0.001) levels.
Conclusion:
We observed a significant negative correlation between BMI and cognitive functioning, and a significant positive correlation between BMI and inflammation in persons with PCC, suggesting a bidirectional interplay between BMI, PCC, and cognitive function; individuals with an elevated BMI may be at a greater risk of developing PCC and/or presenting with greater cognitive deficits mediated by chronic systemic inflammation.
Work on the electoral effects of gun violence in the U.S. relying on difference-in-differences designs has produced findings ranging from null to substantively large effects. However, as difference-in-difference designs, on which this research relies, have exploded in popularity, scholars have documented several methodological issues including potential violations of parallel-trends and unaccounted for treatment effect heterogeneity. These pitfalls (and their solutions) have not been fully explored in political science. We apply these advancements to the unresolved debate on gun violence’s effects on U.S. electoral outcomes. We show that studies finding a large positive effect of gun violence on Democratic vote shares are a product of a failure to properly specify difference-in-differences models when underlying assumptions are unlikely to hold. Once these biases are corrected, shootings show little evidence of sparking large electoral change. Our work clarifies an unresolved debate and provides a cautionary guide for scholars currently employing difference-in-differences designs.
Faecal examinations for helminth eggs were performed on 1869 people from two riverside localities, Vientiane Municipality and Saravane Province, along the Mekong River, Laos. To obtain adult flukes, 42 people positive for small trematode eggs (Opisthorchis viverrini, heterophyid, or lecithodendriid eggs) were treated with a 20–30 mg kg−1 single dose of praziquantel and purged. Diarrhoeic stools were then collected from 36 people (18 in each area) and searched for helminth parasites using stereomicroscopes. Faecal examinations revealed positive rates for small trematode eggs of 53.3% and 70.8% (average 65.2%) in Vientiane and Saravane Province, respectively. Infections with O. viverrini and six species of intestinal flukes were found, namely, Haplorchistaichui, H. pumilio, H. yokogawai, Centrocestus caninus,Prosthodendrium molenkampi, and Phaneropsolus bonnei. The total number of flukes collected and the proportion of fluke species recovered were markedly different in the two localities; in Vientiane, 1041 O. viverrini (57.8 per person) and 615 others (34.2 per person), whereas in Saravane, 395 O. viverrini (21.9 per person) and 155207 others (8622.6 per person). Five people from Saravane harboured no O. viverrini but numerous heterophyid and/or lecithodendriid flukes. The results indicate that O. viverrini and several species of heterophyid and lecithodendriid flukes are endemic in these two riverside localities, and suggest that the intensity of infection and the relative proportion of fluke species vary by locality along the Mekong River basin.
The thermal maturity of samples of the Posidonia Shale collected from the Hils Syncline, northern Germany, varies significantly as a function of location indicating variations in local history. Synchrotron X-ray diffraction was used to document the composition and the preferred orientation of four samples of the Posidonia Shale with different degrees of maturity (0.68–1.45%, Ro) to determine possible effects on diagenesis and preferred orientation. Overall, the degree of preferred orientation of all clay minerals (illite-smectite, illite-mica, and kaolinite) and in all samples is similar, with (001) pole figure maxima ranging from 3.7 to 6.3 multiples of a random distribution (m.r.d.). Calcite displays weak preferred orientation, with c axes perpendicular to the bedding plane (1.1–1.3 m.r.d.). Other constituent phases such as quartz, feldspars, and pyrite have a random orientation distribution. The difference in thermal history, which causes significant changes in the maturity of organic matter, influenced the preferred orientation of clay minerals only marginally as most of the alignment seems to have evolved early in their history. Synchrotron X-ray microtomography was used to characterize the three-dimensional microstructure of a high-maturity sample. Low-density features, including porosity, fractures, and kerogen, were observed to be elongated and aligned roughly parallel to the bedding plane. The volume of low-density features was estimated to be ~7 vol.%, consistent with previous petrophysical measurements of porosity of 8–10 vol.%. Transmission electron microscopy analysis of samples with different degrees of maturity (0.74%Ro and 1.45%Ro) was used to document microstructures at the nanoscale as well as the presence of kerogen. In the high-maturity sample, pores were less abundant while minerals were more deformed as shown by fractured calcite and by kinked and folded illite. Some of the porosity was aligned with clay platelets.
In the Nuussuaq Basin, West Greenland, a thick succession of Tertiary dolerites has penetrated Upper Cretaceous mudstone. The mixed-layer minerals of mudstone core samples have been analyzed by X-ray diffraction, solid-state 29Si and 27A1 magic-angle spinning nuclear magnetic resonance, Mössbauer and infrared spectroscopies, thermal analysis, chemical analysis, stable isotopes (18O/16O), and K/Ar dating. The mixed-layer minerals include for each sample two mixed-layer phases consisting of pyrophyllite, margarite, paragonite, tobelite, illite, smectite and vermiculite layers. The main, 80 m thick intrusion resulted in the formation of pyrophyllite, margarite, paragonite and tobelite layers. However, the tobelite layers are absent in samples <21 m from this intrusion. Furthermore, chlorite was formed and kaolinite destroyed in samples adjacent to minor intrusions and at distances <60 m from the large intrusion. For the first time, the detailed, complex mixed-layer structures formed during contact metamorphism of kaolinitic, oil-forming mudstones have been investigated accurately. The formation of tobelite layers reveals that oil formation has taken place during contact metamorphism. Furthermore, K/Ar dating of mixed-layer minerals from shale indicates that the intrusives are of early Eocene age. The 80 m thick intrusive is responsible for the main mixed-layer transformations, whereas two thin (3 m and 0.5 m thick) intrusions contribute little. Thus, the detailed mixed-layer investigation has contributed significantly to the understanding of the regional geology and the contact metamorphic processes.
A classic lift decomposition (Von Kármán & Sears, J. Aeronaut. Sci., vol. 5, 1938, pp. 379–390) is conducted on potential flow simulations of a near-ground pitching hydrofoil. It is discovered that previously observed stable and unstable equilibrium altitudes are generated by a balance between positive wake-induced lift and negative quasi-steady lift while the added mass lift does not play a role. Using both simulations and experiments, detailed analyses of each lift component's near-ground behaviour provide further physical insights. When applied to three-dimensional pitching hydrofoils the lift decomposition reveals that the disappearance of equilibrium altitudes for ${A{\kern-4pt}R}\ {\rm (aspect\ ratio)} <1.5$ occurs due to the magnitude of the quasi-steady lift outweighing the magnitude of the wake-induced lift at all ground distances. Scaling laws for the quasi-steady lift, wake-induced lift and the stable equilibrium altitude are discovered. A simple scaling law for the lift of a steady foil in ground effect is derived. This scaling shows that both circulation enhancement and the velocity induced at a foil's leading edge by the bound vortex of its ground image foil are the essential physics to understand steady ground effect. The scaling laws for unsteady pitching foils can predict the equilibrium altitude to within $20\,\%$ of its value when $St\ {\rm (Strouhal\ number)} < 0.45$. For $St \ge 0.45$ there is a wake instability effect, not accounted for in the scaling relations, that significantly alters the wake-induced lift. These results not only provide key physical insights and scaling laws for steady and unsteady ground effects, but also for two schooling hydrofoils in a side-by-side formation with an out-of-phase synchronization.
The refraction of surface gravity waves by currents leads to spatial modulations in the wave field and, in particular, in the significant wave height. We examine this phenomenon in the case of waves scattered by a localised current feature, assuming (i) the smallness of the ratio between current velocity and wave group speed, and (ii) a swell-like, highly directional wave spectrum. We apply matched asymptotics to the equation governing the conservation of wave action in the four-dimensional position–wavenumber space. The resulting explicit formulas show that the modulations in wave action and significant wave height past the localised current are controlled by the vorticity of the current integrated along the primary direction of the swell. We assess the asymptotic predictions against numerical simulations using WAVEWATCH III for a Gaussian vortex. We also consider vortex dipoles to demonstrate the possibility of ‘vortex cloaking’ whereby certain currents have (asymptotically) no impact on the significant wave height. We discuss the role of the ratio of the two small parameters characterising assumptions (i) and (ii) above, and show that caustics are significant only for unrealistically large values of this ratio, corresponding to unrealistically narrow directional spectra.
Early neurodevelopmental deviations, such as abnormal cortical folding patterns, are a candidate biomarker for major depressive disorder (MDD). Previous studies on patterns of abnormal cortical gyrification in MDD have provided valuable insights; however, the findings on cortical folding are controversial.
Objectives
We aimed to investigate the association of MDD with the local gyrification index (LGI) in each cortical region at the whole-brain level and the association of the LGI with clinical characteristics of MDD, including recurrence, remission status, illness duration, severity of depression, and medication status of patients with MDD.
Methods
We obtained T1-weighted images of 234 patients with MDD and 215 healthy controls (HCs). LGI values were automatically calculated using the FreeSurfer software according to the Desikan–Killiany atlas. LGI values from 66 cortical regions in the bilateral hemispheres were analyzed. We compared the LGI values between the MDD and HC groups using the analysis of covariance, including patients’ age, sex, and years of education as covariates. The association between clinical characteristics and LGI values was investigated in the MDD group.
Results
Compared with HCs, patients with MDD showed significantly decreased LGI values in the cortical regions, including the bilateral ventrolateral and dorsolateral prefrontal cortices, medial and lateral orbitofrontal cortices, insula, right rostral anterior cingulate cortex, and several temporal and parietal regions, with the highest effect size in the left pars triangularis (Cohen’s f = 0.361; P = 1.78 × 10-13). As for the association of clinical characteristics with LGIs within the MDD group, recurrence and longer illness duration of MDD were associated with increased gyrification in several occipital and temporal regions, which showed no significant difference in LGIs between MDD and HC groups.
Conclusions
Considering that the aforementioned cortical regions are involved in emotion regulation, abnormal cortical folding patterns in such regions may be associated with the dysfunction of emotion regulation-related neural circuits, which may lead to MDD. These findings suggest that LGI may be a relatively stable neuroimaging marker associated with the trait of MDD predisposition.
In this paper, a super-twisting disturbance observer (STDO)-based adaptive reinforcement learning control scheme is proposed for the straight air compound missile system with aerodynamic uncertainties and unmodeled dynamics. Firstly, neural network (NN)-based adaptive reinforcement learning control scheme with actor-critic design is investigated to deal with the tracking problems for the straight gas compound system. The actor NN and the critic NN are utilised to cope with the unmodeled dynamics and approximate the cost function that are related to control input and tracking error, respectively. In other words, the actor NN is used to perform the tracking control behaviours, and the critic NN aims to evaluate the tracking performance and give feedback to actor NN. Moreover, with the aid of the STDO disturbance observer, the problem of the control signal fluctuation caused by the mismatched disturbance can be solved well. Based on the proposed adaptive law and the Lyapunov direct method, the eventually consistent boundedness of the straight gas compound system is proved. Finally, numerical simulations are carried out to demonstrate the feasibility and superiority of the proposed reinforcement learning-based STDO control algorithm.