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The dynamics, structure and stability of zonal jets in planetary flows are still poorly understood, especially in terms of coupling with the small-scale turbulent flow. Here, we use an experimental approach to address the questions of zonal jets formation and long-term evolution. A strong and uniform topographic $\beta$-effect is obtained inside a water-filled rotating tank thanks to the paraboloidal fluid free upper surface combined with a specifically designed bottom plate. A small-scale turbulent forcing is performed by circulating water through the base of the tank. Time-resolving particle image velocimetry measurements reveal the self-organization of the flow into multiple zonal jets with a strong instantaneous signature. We identify a subcritical bifurcation between two regimes of jets depending on the forcing intensity. In the first regime, the jets are steady, weak in amplitude, and directly forced by the local Reynolds stresses due to our forcing. In the second one, we observe highly energetic and dynamic jets of width larger than the forcing scale. An analytical modelling based on the quasi-geostrophic approximation reveals that this subcritical bifurcation results from the resonance between the directly forced Rossby waves and the background zonal flow.
This study explores experimentally the flows driven by precession in an oblate spheroid, in the vicinity of the possible resonance with the tilt-over mode. Two main phenomena are reported, combining observations and velocity measurements. First, a hysteretic cycle is quantitatively described between two uniform vorticity solutions, in good agreement with the historical analytical study of Busse (J. Fluid Mech., vol. 33, 1968, pp. 739–752). We then address the destabilization of each branch at low enough Ekman number. We confirm the possible presence of a so-called conical shear instability, recently depicted in the sphere by Lin et al. (Phys. Fluids, vol. 27, 2015, 046601) and in the spheroid by Horimoto et al. (Phys. Rev. Fluids, vol. 5, 2020, 063901). However, available measurements in the accessible parameter range are not sufficient to definitively discard an elliptical or shear origin of the excited instabilities in the spheroid, as first introduced by Kerswell (Geophys. Astrophys. Fluid Dyn., vol. 72, 1993, pp. 107–144).
Up until now, there is much debate about the role of asymptomatic patients and pauci-symptomatic patients in severe acute respiratory syndrome novel coronavirus 2 (SARS-CoV-2) transmission, and little is known about the kinetics of viral ribonucleic acid (RNA) shedding in these populations. This article aims to describe key features and the nature of asymptomatic and pauci-symptomatic SARS-CoV-2 infected patients. The cohort consisted of six participants, three pairs, which were infected with SARS-CoV-2 during February 2020 on board the Diamond Princess. Of the six confirmed (reverse transcription polymerase chain reaction [RT-PCR]) cases, four were initially diagnosed in Japan and two upon their arrival to Israel. Duration of infection was between four days and up to 26 days. Of the six patients, three were completely asymptomatic and the others were pauci-symptomatic. All five patients in whom a computerized tomography (CT) scan was performed had lung pathology. In one patient, infectivity was tested using cell culture and a cytopathic effect was demonstrated. A serology test was performed in three of the patients and all three had a positive immunoglobulin G (IgG) four to eight weeks after disease onset. This case series demonstrates that asymptomatic and pauci-symptomatic patients may play a role in infection transmission by demonstrating probable transmission among asymptomatic spouses and by demonstrating a viable virus via a cell culture. Additionally, asymptomatic and pauci-symptomatic patients can have lung pathology and developing IgG antibodies.
While taxonomy segregates anxiety symptoms into diagnoses, patients typically present with multiple diagnoses; this poses major challenges, particularly for youth, where mixed presentation is particularly common. Anxiety comorbidity could reflect multivariate, cross-domain interactions insufficiently emphasized in current taxonomy. We utilize network analytic approaches that model these interactions by characterizing pediatric anxiety as involving distinct, inter-connected, symptom domains. Quantifying this network structure could inform views of pediatric anxiety that shape clinical practice and research.
Participants were 4964 youths (ages 5–17 years) from seven international sites. Participants completed standard symptom inventory assessing severity along distinct domains that follow pediatric anxiety diagnostic categories. We first applied network analytic tools to quantify the anxiety domain network structure. We then examined whether variation in the network structure related to age (3-year longitudinal assessments) and sex, key moderators of pediatric anxiety expression.
The anxiety network featured a highly inter-connected structure; all domains correlated positively but to varying degrees. Anxiety patients and healthy youth differed in severity but demonstrated a comparable network structure. We noted specific sex differences in the network structure; longitudinal data indicated additional structural changes during childhood. Generalized-anxiety and panic symptoms consistently emerged as central domains.
Pediatric anxiety manifests along multiple, inter-connected symptom domains. By quantifying cross-domain associations and related moderation effects, the current study might shape views on the diagnosis, treatment, and study of pediatric anxiety.
We explore the near-resonant interaction of inertial waves with geostrophic modes in rotating fluids via numerical and theoretical analysis. When a single inertial wave is imposed, we find that some geostrophic modes are unstable above a threshold value of the Rossby number
based on the wavenumber and wave amplitude. We show this instability to be caused by triadic interaction involving two inertial waves and a geostrophic mode such that the sum of their eigenfrequencies is non-zero. We derive theoretical scalings for the growth rate of this near-resonant instability. The growth rate scaled by the global rotation rate is proportional to
and transitions to a
scaling for larger
. These scalings are in excellent agreement with direct numerical simulations. This instability could explain recent experimental observations of geostrophic instability driven by waves.
Recent research on late-life depression (LLD) pathophysiology suggests the implication of abnormalities in cerebral white matter  and particularly in interhemispheric transfer . Corpus callosum (CC) is the main brain interhemispheric commissure . Hence, we investigated the association between baseline CC measures and risk of LDD.
We studied 467 non-demented individuals without LLD at baseline from a cohort of community-dwelling people aged 80 years or younger (the ESPRIT study). LLD was assessed at year 2, 4, 7 and 10 of the study follow-up. At baseline, T1-weighted magnetic resonance images were manually traced to measure the mid-sagittal areas of the anterior, mid and posterior CC. Multivariate Cox proportional hazards models stratified by sex were used to predict LLD incidence over 10 years.
A significant interaction between gender and CC size was found (P = 0.02). LLD incidence in elderly women, but not in men, was significantly associated with smaller anterior (HR 1.37 [1.05–1.79] P = 0.017), mid (HR 1.43 [1.09–1.86] P = 0.008), posterior (HR1.39 [1.12–1.74] P = 0.002) and total (HR 1.53 [1.16–2.00] P = 0.002) CC areas at baseline in Cox models adjusted for age, education, global cognitive impairment, ischemic pathologies, left-handedness, white matter lesion, intracranial volume and past depression.
The main limitation was the retrospective assessment of major depression.
Smaller CC size is a predictive factor of incident LLD over 10 years in elderly women. Our finding suggests a possible role of CC and reduced interhemispheric connectivity in LLD pathophysiology. Extensive explorations are needed to clarify the mechanisms leading to CC morphometric changes in mood disorders.
Previous studies have observed reduced vagal modulation in patients with acute schizophrenia and their first degree relatives, thus suggesting a genetic predisposition.
To investigate vagal modulation at brain stem level, we investigated the coupling between heart rate and breathing as a putative measure of central autonomic function in 19 patients, 19 of their relatives and 19 matched control subjects. The interaction of heart rate and breathing was investigated in all groups applying the non-linear parameter cross-ApEn, indicating the asynchrony between both time series.
The main finding of our study is a significantly increased cross-ApEn value, indicating reduced central vagal modulation both in relatives and patients suffering from schizophrenia.
Our results suggest that autonomic dysfunction in schizophrenia is present in first-degree relatives not only at the target organs as shown previously, but also affects the central vagal component.
Benzodiazepine (BDZ) abuse highly prevalent among former heroin addicts, currently in methadone maintenance treatment. Discontinuation of BDZ abuse is accompanied by sleep disturbances. We evaluated the effectiveness of melatonin in attenuating sleep difficulties in a BDZ withdrawal program.
Patients in a managed BDZ withdrawal program entered a double blind crossover control study with melatonin or placebo: 6 weeks one arm, one week washout, 6 weeks other arm. Urine BDZ, the self reported Pittsburgh Sleep Quality Index (PSQI) and the Center for Epidemiologic Studies Depression (CES-D, mood) questionnaire were administered at baseline, and after 6, 8 and 13 weeks.
Eighty patients were randomly assigned into two arms. Both groups (n=40) had similar baseline PSQI (13.8±3.8) and CES-D (1.5±0.6) scores, which correlated (R=0.4, p=0.001). Sixty one patients (77.5% in "melatonin-first" and 75% in "placebo first") finished 6 weeks, showing similar BDZ discontinuation rate 11/31 and 11/30 respectively. PSQI scores were significantly lower (better sleep) in the 22 patients who discontinued BDZ (8.9±4.4) than in 39 with urine BDZ (11.2±4.2 p=0.04). Interaction between study groups and BDZ groups showed that sleep quality in patients who continued abusing BDZ improved more in the "melatonin first" group than in the "placebo first" group, with no differences in sleep quality improvement in patients who stopped BDZ (F=4.3, p=0.04).
Most improvement in sleep quality was attributed to BDZ discontinuation. Although melatonin did not enhance BDZ discontinuation, it improved sleep quality, especially in patients who did not stop BDZ.
Co-morbit medical conditions such as hyperglycemia, diabetes, hypertension are frequent in psychiatric patients. Tragically, this population is less likely to receive necessary medical care during hospitalization and has higher rates of morbidity and mortality from medical illnesses when compared with nonpsychiatric population. The present study evaluated for diagnosis and management of comorbit medical conditions in hospitalized patients with and without mental illness.
The study group consisted of 200 hospitalized subjects, including 100 subjects with schizophrenia and bipolar disorder and 100 age-matched controls. All patients were evaluated for a comorbit conditions, concomitant medication, biochemical parameters (glucose, lipids, CRP) and blood pressure.
Two groups were similar in terms of age, gender, blood pressure, glucose and lipids. The overall frequency of previously diagnosed medical conditions such as hypertension, dyslipidemia and diabetes was significantly lower in psychiatric patients compared with nonpsychiatric population, regardless of the similar presence of these conditions according NCEP criteria in two groups. Significantly fewer subjects in psychiatric group received aspirin, statins, antihypertensive and antidiabetic medications. Although more obesity was diagnosed in psychiatric patients; significantly less diet intervention has been performed during hospitalization. While significantly more smokers and more pulmonary hospitalization were in psychiatric group, fewer subjects in this group received instruction for smoking cessation compared with nonpsychiatric population.
Hospitalization is the opportunity to bridge the gap between mental and physical health. However, comorbit medical conditions such as diabetes, hypertension, dyslipidemia and obesity are frequently underdiagnosed and undertreated in hospitalized psychiatric patients compared with nonpsychiatric population.
Sleep disturbances are common complains among schizophrenia patients. Based on these subjective complaints, treatment often involves hypnotic and/or anxiolytic medications with disturbing side effects that increase patients' drug load. Most hypnosedatives are prescribed based on subjective complaints, but little information is published on the relationship between self-report and recorded sleep in this population.
The present study examined the correlation between subjective and objective evaluation of sleep measures among schizophrenia patients compared with age- and gender-matched controls.
The sample comprised two groups: 30 schizophrenia patients (mean age=48.50, SD=12.45; 17 M, 13 F) and 30 age- and gender-matched controls (mean age= 48.56, SD=12.54; 17 M, 13 F). Subjects subjectively evaluated their sleep patterns using two qualitative reports–the Mini Sleep Questionnaire (MSQ), and Pittsburgh Sleep Quality Index (PSQI), and one quantitative report–the Technion Sleep Questionnaire (TSQ). Additionally, subjects' sleep was continuously monitored for a week with a wrist actigraph (Ambulatory Monitoring, Inc.).
Analysis revealed no significant correlations between subjective and objective measures of sleep in all participants. Interestingly, significant interactions were found between estimation type of the discrepancy (overestimate vs. underestimate) and schizophrenia existence (schizophrenia patients vs. controls) on discrepancy of sleep efficiency [F(1,51)=6.2, p<0.05], sleep percentage [F(1,54)=8.86, p<0.01] and minutes of wake after sleep onset [F(1,51)=9.24, p<0.01]; meaning that schizophrenia patients display greater discrepancies than controls.
The findings indicate that subjective reports among schizophrenia patients are unreliable, and argue for objectively evaluating sleep in this population before prescribing sleep medications.
The purpose of this paper was to examine national differences in the desire to participate in decision-making of people with severe mental illness in six European countries.
The data was taken from a European longitudinal observational study (CEDAR; ISRCTN75841675). A sample of 514 patients with severe mental illness from the study centers in Ulm, Germany, London, England, Naples, Italy, Debrecen, Hungary, Aalborg, Denmark and Zurich, Switzerland were assessed as to desire to participate in medical decision-making. Associations between desire for participation in decision-making and center location were analyzed with generalized estimating equations.
We found large cross-national differences in patients’ desire to participate in decision-making, with the center explaining 47.2% of total variance in the desire for participation (P < 0.001). Averaged over time and independent of patient characteristics, London (mean = 2.27), Ulm (mean = 2.13) and Zurich (mean = 2.14) showed significantly higher scores in desire for participation, followed by Aalborg (mean = 1.97), where scores were in turn significantly higher than in Debrecen (mean = 1.56). The lowest scores were reported in Naples (mean = 1.14). Over time, the desire for participation in decision-making increased significantly in Zurich (b = 0.23) and decreased in Naples (b = −0.14). In all other centers, values remained stable.
This study demonstrates that patients’ desire for participation in decision-making varies by location. We suggest that more research attention be focused on identifying specific cultural and social factors in each country to further explain observed differences across Europe.
Background: There is an unmet need for blood-based biomarkers that can reliably detect MS disease activity. Serum Biomarkers of interest includ Neurofilament-light-chain (NfL), Glial-fibrillary-strocyte-protein(GFAP) and Tau. Bone Marrow Transplantation (BMT) is reserved for aggressive forms of MS and has been shown to halt detectable CNS inflammatory activity for prolonged periods. Significant pre-treatment tissue damage at followed by inflammatory disease abeyance should be reflected longitudinal sera collected from these patients. Methods: Sera were collected from 23 MS patients pre-treatment, and following BMT at 3, 6, 9 and 12-months in addition from 33 non-inflammatory neurological controls. Biomarker quantification was performed with SiMoA. Results: Pre-AHSCT levels of serum NfL and GFAP but not Tau were elevated compared to controls (p=0.0001), and NfL correlated with lesion-based disease activity (6-month-relapse, MRI-T2 and Gadolinium-enhancement). 3-months post-treatment, while NfL levels remained elevated, Tau/GFAP paradoxically increased (p=0.0023/0.0017). These increases at 3m correlated with MRI ‘pseudoatrophy’ at 6-months. NfL/Tau levels dropped to that of controls by 6-months (p=0.0036/0.0159). GFAP levels dropped progressively after 6-months although even at 12-months remained higher than controls (p=0.004). Conclusions: NfL was the closest correlate of MS disease activity and treatment response. Chemotherapy-related toxicity may account for transient increases in NfL, Tau and MRI brain atrophy post-BMT.
Highly resolved, well-dated paleoclimate records from the southern South African coast are needed to contextualize the evolution of the highly diverse extratropical plant communities of the Greater Cape Floristic Region (GCFR) and to assess the environmental impacts on early human hunter-gatherers. We present new speleothem stable oxygen and carbon isotope ratios (δ18Oc and δ13C) from two caves at Pinnacle Point, South Africa, covering the time between 330 and 43 ka. Composite δ18Oc and δ13C records were constructed for Staircase Cave and PP29 by combining all stable isotope analyses into a single time series and smoothing by a 3-point running mean. δ18Oc and δ13C values record changes in rainfall seasonality and the proportions of C3 and C4 plants in the vegetation, respectively. We show that in general increased summer rainfall brought about a wider spread of C4 grasses and retreat of the C3 plant–dominated GCFR communities. The occurrence of summer rainfall on the southern coast of South Africa was linked to total rainfall amounts in the interior region through tropical temperate troughs. These rainfall systems shifted the southern coastal climate toward more summer (winter) rainfall when precession was high (low) and/or the westerlies were in a northern (southern) position.
Using water–salt water laboratory experiments, we investigate the mechanism of erosion by a turbulent jet impinging onto a density interface, for moderate Reynolds and Froude numbers. The Froude number is defined by
, the typical velocity and width of the jet at the interface, and
the reduced gravitational acceleration. The Froude number
characterizes the competition between inertial forces against the restoring buoyancy force. Contrary to previous observations reporting baroclinic destabilization of the interface, we show that the entrainment, in the range of parameters explored here, is driven by interfacial gravity waves. The waves are generated by the barotropic excitation coming from the turbulent fluctuations of the jet; they are then amplified by a mechanism of wave-induced stress; and they finally break and induce entrainment and mixing. Based on those physical observations, we introduce a scaling model for the entrainment rate, which varies continuously from
power law from small to large Froude numbers, in agreement with the present and some of the previous laboratory data.
Efficacy of pre-trauma prevention for post-traumatic stress disorder (PTSD) has not yet been established in a randomized controlled trial. Attention bias modification training (ABMT), a computerized intervention, is thought to mitigate stress-related symptoms by targeting disruptions in threat monitoring. We examined the efficacy of ABMT delivered before combat in mitigating risk for PTSD following combat.
We conducted a double-blind, four-arm randomized controlled trial of 719 infantry soldiers to compare the efficacy of eight sessions of ABMT (n = 179), four sessions of ABMT (n = 184), four sessions of attention control training (ACT; n = 180), or no-training control (n = 176). Outcome symptoms were measured at baseline, 6-month follow-up, 10 days following combat exposure, and 4 months following combat. Primary outcome was PTSD prevalence 4 months post-combat determined in a clinical interview using the Clinician-Administered PTSD Scale. Secondary outcomes were self-reported PTSD and depression symptoms, collected at all four assessments.
PTSD prevalence 4 months post-combat was 7.8% in the no-training control group, 6.7% with eight-session ABMT, 2.6% with four-session ABMT, and 5% with ACT. Four sessions of ABMT reduced risk for PTSD relative to the no-training condition (odds ratio 3.13, 95% confidence interval 1.01–9.22, p < 0.05, number needed to treat = 19.2). No other between-group differences were found. The results were consistent across a variety of analytic techniques and data imputation approaches.
Four sessions of ABMT, delivered prior to combat deployment, mitigated PTSD risk following combat exposure. Given its low cost and high scalability potential, and observed number needed to treat, research into larger-scale applications is warranted. The ClinicalTrials.gov identifier is NCT01723215.
Modern conceptions of brain function consider the brain as a “predictive organ,” where learned regularities about the world are utilised to facilitate perception of incoming sensory input. Critically, this process hinges on a role for cognitive penetrability. We review a mechanism to explain this process and expand our previous proposals of cognitive penetrability in visual recognition to social vision and visual hallucinations.