To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This note describes improvements of UV oxidation method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). The procedural blank is reduced to 2.6 ± 0.6 μg C, with Fm of 0.42 ± 0.10 and δ13C of –28.43 ± 1.19‰. The throughput is improved from one sample per day to two samples per day.
In this paper, we expolore Multi-Agent Reinforcement Learning (MARL) methods for unmanned aerial vehicle (UAV) cluster. Considering that the current UAV cluster is still in the program control stage, the fully autonomous and intelligent cooperative combat has not been realised. In order to realise the autonomous planning of the UAV cluster according to the changing environment and cooperate with each other to complete the combat goal, we propose a new MARL framework. It adopts the policy of centralised training with decentralised execution, and uses Actor-Critic network to select the execution action and then to make the corresponding evaluation. The new algorithm makes three key improvements on the basis of Multi-Agent Deep Deterministic Policy Gradient (MADDPG) algorithm. The first is to improve learning framework; it makes the calculated Q value more accurate. The second is to add collision avoidance setting, which can increase the operational safety factor. And the third is to adjust reward mechanism; it can effectively improve the cluster’s cooperative ability. Then the improved MADDPG algorithm is tested by performing two conventional combat missions. The simulation results show that the learning efficiency is obviously improved, and the operational safety factor is further increased compared with the previous algorithm.
Sex-related differences in psychopathology are known phenomena, with externalizing and internalizing symptoms typically more common in boys and girls, respectively. However, the neural correlates of these sex-by-psychopathology interactions are underinvestigated, particularly in adolescence.
Participants were 14 years of age and part of the IMAGEN study, a large (N = 1526) community-based sample. To test for sex-by-psychopathology interactions in structural grey matter volume (GMV), we used whole-brain, voxel-wise neuroimaging analyses based on robust non-parametric methods. Psychopathological symptom data were derived from the Strengths and Difficulties Questionnaire (SDQ).
We found a sex-by-hyperactivity/inattention interaction in four brain clusters: right temporoparietal-opercular region (p < 0.01, Cohen's d = −0.24), bilateral anterior and mid-cingulum (p < 0.05, Cohen's d = −0.18), right cerebellum and fusiform (p < 0.05, Cohen's d = −0.20) and left frontal superior and middle gyri (p < 0.05, Cohen's d = −0.26). Higher symptoms of hyperactivity/inattention were associated with lower GMV in all four brain clusters in boys, and with higher GMV in the temporoparietal-opercular and cerebellar-fusiform clusters in girls.
Using a large, sex-balanced and community-based sample, our study lends support to the idea that externalizing symptoms of hyperactivity/inattention may be associated with different neural structures in male and female adolescents. The brain regions we report have been associated with a myriad of important cognitive functions, in particular, attention, cognitive and motor control, and timing, that are potentially relevant to understand the behavioural manifestations of hyperactive and inattentive symptoms. This study highlights the importance of considering sex in our efforts to uncover mechanisms underlying psychopathology during adolescence.
Dry wind-tunnel (DWT) flutter test systems model the unsteady distributed aerodynamic force using various electromagnetic exciters. They can be used to test the aeroelastic and aeroservoelastic stability of smart aircraft or high-speed flight vehicles. A new parameterised modelling method at the full system level based on the generalised force equivalence for DWT flutter systems is proposed herein. The full system model includes the structural dynamic model, electromechanical coupling model and fast aerodynamic computation model. An optimisation search method is applied to determine the best locations for measurement and excitation by introducing Fisher’s information matrix. The feasibility and accuracy of the proposed system-level numerical DWT modelling method have been validated for a plate aeroelastic model with four exciters/transducers. The effects of key parameters including the number of exciters, the control time delay, the noise interference and the electrical parameters of the electromagnetic exciter model have also been investigated. The numerical and experimental results indicate that the proposed modelling method achieves good accuracy (with deviations of less than 1.5% from simulations and 4.5% from experimental test results for the flutter speed) and robust performance even in uncertain environments with a 10% noise level.
More than 50% patients with major depressive disorder (MDD) have severe functional impairment. The restoration of patient functioning is a critical therapeutic goal among patients with MDD. We conducted a systematic review and network meta-analysis to evaluate the efficacy of pharmacological treatments on self-rated functional outcomes using the Sheehan Disability Scale in adults with MDD in randomized clinical trials.
PubMed, EMBASE, PsycINFO, Cochrane Library, and ClinicalTrials.gov were searched from inception to December 10, 2019. Summary statistics are reported as weighted mean differences with 95% confidence intervals. Interventions were ranked using the surface under the cumulative ranking probabilities.
We included 42 randomized controlled trials (RCTs) (n = 18 998) evaluating the efficacy of 13 different pharmacological treatments on functional outcomes, as measured by the Sheehan Disability Scale (SDS). Duloxetine was the most effective pharmacological agent on functional outcomes, followed by (ranked by efficacy): paroxetine, levomilnacipran, venlafaxine, quetiapine, desvenlafaxine, agomelatine, escitalopram, amitriptyline, bupropion, sertraline, vortioxetine, and fluoxetine. Serotonin and norepinephrine reuptake inhibitors were more effective than other drug classes. Additionally, the comparison-adjusted funnel plot suggested the publication bias between small and large studies was relatively low.
Our results indicate that there may be differences across antidepressant agents and classes with respect to self-reported functional outcomes. Validation and replication of these findings in large-scale RCTs are warranted. Our research results will be clinically useful for guiding psychiatrists in treating patients with MDD and functional impairment. PROSPERO registration number CRD42018116663.
Lifestyle interventions are an important and viable approach for preventing cognitive deficits. However, the results of studies on alcohol, coffee and tea consumption in relation to cognitive decline have been divergent, likely due to confounds from dose–response effects. This meta-analysis aimed to find the dose–response relationship between alcohol, coffee or tea consumption and cognitive deficits.
Prospective cohort studies or nested case-control studies in a cohort investigating the risk factors of cognitive deficits were searched in PubMed, Embase, the Cochrane and Web of Science up to 4th June 2020. Two authors searched the databases and extracted the data independently. We also assessed the quality of the studies with the Newcastle-Ottawa scale. Stata 15.0 software was used to perform model estimation and plot the linear or nonlinear dose–response relationship graphs.
The search identified 29 prospective studies from America, Japan, China and some European countries. The dose–response relationships showed that compared to non-drinkers, low consumption (<11 g/day) of alcohol could reduce the risk of cognitive deficits or only dementias, but there was no significant effect of heavier drinking (>11 g/day). Low consumption of coffee reduced the risk of any cognitive deficit (<2.8 cups/day) or dementia (<2.3 cups/day). Green tea consumption was a significant protective factor for cognitive health (relative risk, 0.94; 95% confidence intervals, 0.92–0.97), with one cup of tea per day brings a 6% reduction in risk of cognitive deficits.
Light consumption of alcohol (<11 g/day) and coffee (<2.8 cups/day) was associated with reduced risk of cognitive deficits. Cognitive benefits of green tea consumption increased with the daily consumption.
The aim of the present study was to identify reports of the prevalence of tinnitus in China and to present these findings in a review format.
This study assessed and collated published prevalence estimates of tinnitus and tinnitus severity, creating a narrative synthesis of the data from publications identified from a combination of Chinese and English language databases.
A total of 23 studies were included. Tinnitus prevalence ranged from 4.3 per cent to 51.33 per cent but varied with age and gender. The highest increase in prevalence from previous decade in age occurs during the fifth and sixth decades, and the highest prevalence was in the seventh decade at 32.47 per cent. There is also evidence that tinnitus prevalence is related to certain risk factors including comorbid disorders.
The prevalence of tinnitus in mainland China in this study is consistent with global data. With increasing awareness of the prevalence of tinnitus in China, the development of epidemiological standards is a priority.
This study describes a procedural blank assessment of the ultraviolet photochemical oxidation (UV oxidation) method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). A retrospective compilation of Fm and δ13C results for secondary standards (OX-II, glycine) between 2009 and 2018 indicated that a revised blank correction was required to bring results in line with accepted values. The application of a best-fit mass-balance correction yielded a procedural blank of 22.0 ± 6.0 µg C with Fm of 0.30 ± 0.20 and δ13C of –32.0 ± 3.0‰ for this period, which was notably higher and more variable than previously reported. Changes to the procedure, specifically elimination of higher organic carbon reagents and improved sample and reactor handling, reduced the blank to 11.0 ± 2.75 µg C, with Fm of 0.14 ± 0.10 and δ13C of –31.0 ± 5.5‰. A thorough determination of the entire sample processing blank is required to ensure accurate isotopic compositions of seawater DOC using the UV oxidation method. Additional efforts are needed to further reduce the procedural blank so that smaller DOC samples can be analyzed, and to increase sample throughput.
Tooth enamel, the outermost layer of human teeth, is a complex, hierarchically structured biocomposite. The details of this structure are important in multiple human health contexts, from understanding the progression of dental caries (tooth decay) to understanding the process of amelogenesis and related developmental defects. Enamel is composed primarily of long, nanoscale crystallites of hydroxyapatite that are bundled by the thousands to form micron-scale rods. Studies with transmission electron microscopy show the relationships between small groups of crystallites and X-ray diffraction characterize averages over many rods, but the direct measurement of variations in local crystallographic structure across and between enamel rods has been missing. Here, we describe a synchrotron X-ray-based experimental approach and a novel analysis method developed to address this gap in knowledge. A ~500-nm-wide beam of monochromatic X-rays in conjunction with a sample section only 1 μm in thickness enables 2D diffraction patterns to be collected from small well-separated volumes within the enamel microstructure but still probes enough crystallites (~300 per pattern) to extract population-level statistics on crystallographic features like lattice parameter, crystallite size, and orientation distributions. Furthermore, the development of a quantitative metric to characterize relative order and disorder based on the azimuthal autocorrelation of diffracted intensity enables these crystallographic measurements to be correlated with their location within the enamel microstructure (e.g., between rod and interrod regions). These methods represent a step forward in the characterization of human enamel and will elucidate the variation of the crystallographic structure across and between enamel rods for the first time.
We investigate the phased evolution and variation of the South Asian monsoon and resulting weathering intensity and physical erosion in the Himalaya–Karakoram Mountains since late Pliocene time (c. 3.4 Ma) using a comprehensive approach. Neodymium and strontium isotopic compositions and single-grain zircon U–Pb age spectra reveal the sources of the deposits in the east Arabian Sea, and show a combination of sources from the Himalaya and the Karakoram–Kohistan–Ladakh Mountains, with sediments from the Indian Peninsula such as the Deccan Traps or Craton. We interpret shifts in the sediment sources to have been forced by sea-level changes that correlate with South Asian monsoon rainfall variation since late Pliocene time. We collected 908 samples from the International Ocean Discovery Program Hole U1456A, which was drilled in the east Arabian Sea. Time series of hematite content and grain size of the sediments were examined downcore. We found South Asian monsoon precipitation and weathering intensity experienced three phases from late Pliocene time. Lower monsoon precipitation, with a lower variability and strong weathering intensity, occurred during 3.4–2.4 Ma; an increased and more variable South Asian monsoon rainfall, along with strengthened but fluctuating weathering intensity, occurred at 1.8–1.1 Ma; and a reduced rainfall with lower South Asian monsoon precipitation variability and moderate weathering intensity marked the period 1.1–0.1 Ma. Maximum entropy spectral analysis and wavelet transform show that there were orbital-dominated cycles of periods c. 100 and c. 41 ka in these proxy-based time series. We propose that the monsoon, sea level, global temperature and insolation together forced the weathering and erosion in SW Asia.
Many studies showed the differences in subjective response to sexual stimuli between heterosexual and homosexual men. However, the underlying neurobiological factors of sexual orientation are largely unknown. We addressed the question what is the major attribution of the expected differences in brain activation, i.e. neural circuits or different cognitive process. Twenty-eight healthy male volunteers, 14 heterosexuals and 14 homosexuals, were scanned by functional Magnetic Resonance Imaging while subjects were viewing different types of stimuli, i.e. heterosexual couple stimuli (HCS), gay couple stimuli (GCS), lesbian couple stimuli (LCS) and neutral stimuli (NS). SPM02 was used for data analysis. Rating of sexual attractiveness was assessed. Subjective sexual arousal was induced by HCS and GCS in heterosexual and homosexual men, respectively. And sexual disgust was induced by GCS and LCS in heterosexual and homosexual men, respectively. As compared to viewing NS, viewing sexual stimuli induced significant different brain activations most of which had characteristic for cognitive process. These observations suggested that different cognitive pattern was major attribution of different subjective response to sexual stimuli between heterosexual and homosexual men.
To investigate the effect of Chinese herb Danshen-Dahuang on learning and memory ability in rats with Alzheimer disease (AD) induced by D-galactose and AlCl3 and its possible mechanisms.
The AD model was produced by injecting D-galactose and AlCl3 intraperitoneally for 90 days. Since the 20th day of D-galactose and AlCl3 intraperitoneal injection, the rats in Danshen-Dahuang group had been treated with Danshen-Dahuang extraction by intragastric administration for 70 days. Subsequently,learning and memory ability of the mice was evaluated by Morris water maze and hippocampal gene expression of APP, PS1 was tested by reverse transcription polymerase chain reaction (RT-PCR).
Rats intragastric administration with Danshen-Dahuang, mice had shorter latency (P< 0.05) and less error times (P< 0.05) in water maze test compared with those in AD model group. At the same time, Danshen-Dahuang down regulated the expression of APP, PS1 mRNA (P< 0.05) in hippocampus.
Danshen-Dahuang improves the learning and memory ability of AD rats, its mechanism may be related to the downregulated expression of APP, PS1 mRNA.
Metabolic syndrome induced by atypical antipsychotics is more prevalence in schizophrenic patients. Much less is known regarding paliperidone ER. The objective of this study was to compare matched paliperidone-ER- and olanzapine-treated schizophrenic patients on measures of glucose and lipid metabolism. Eighty hospitalized patients with schizophrenia (DSM-) were randomly assigned to treatment with paliperidone ER or olanzapine for 12 weeks. At baseline and every 4 weeks, we assessed weight, subcutaneous fat, waist and hip circumferences, fasting glucose, insulin, glycohemoglobin A1, cholesterol, triglycerides, high density level (HDL) cholesterol, low density level (LDL) cholesterol and prolactin. And we also evaluate the body mass index (BMI), homeostasis insulin resistance (HOMA-IR) and homeostasis β-cell function (HOMA-B). 33 patients randomly assigned to paliperidone ER and 23 patients randomly assigned to olanzapine completed the entire 12-week treatment. Within-group overall analysis showed that the fasting measures were increased in weight, BMI, waist circumferences, hip circumferences, subcutaneous fat, cholesterol, triglyceride and prolactin for two groups, and fasting glucose, LDL and HOMA-B were increased for olanzapine group. There was significantly difference in serum prolactin between paliperidone ER and olanzapine group. And there was a trend for HOMA-B to increase in olanzapine group over 12 weeks compared to paliperidone ER group. However, there were no overall differential drug effects over 12 weeks on the fasting measures of BMI, glucose, glycohemoglobin A1, insulin, HDL, LDL, cholesterol, triglyceride and HOMA-IR. The study further reinforces the necessity of regular monitoring the metabolic parameters in schizophrenic patients with atypical antipsychotics including paliperidone ER.
This double-blind (DB), relapse prevention, phase-3 study was designed to evaluate the efficacy and safety of paliperidone palmitate long-acting 3-monthly formulation (PP3M) versus placebo in delaying time-to-relapse of schizophrenia symptoms.
Adults (18-70 years old) with schizophrenia (DSM-IV-TR) were treated with PP (17-week, open-label [OL] transition phase: 50, 75, 100, or 150 mg eq, once-monthly, [PP1M]; 12-week OL maintenance phase: 3.5-fold PP1M stabilized dose, single injection), and then randomized (1:1) to PP3M fixed doses (175, 263, 350 or 525 mg eq.) or placebo.
305/506 patients enrolled were randomized (PP3M: n=160; placebo: n=145); majority were men (75%), white (59%), mean age 38.4 years. Interim analysis results favored PP3M vs. placebo (p = 0.0002, two-sided log-rank test; HR: 3.45, 95% CI: 1.73; 6.88); median time-to-relapse was 274 days in placebo and not estimable in PP3M group. Final results were consistent with interim analysis. Both PANSS total score and CGI-S score showed a significant effect over time in PP3M- vs. placebo-treated patients (p>0.001). 330/506 (65.2%) patients in OL phase and 183/305 (60.0%) in DB phase (PP3M: 61.9% vs. placebo: 57.9%) had ≥1 treatment-emergent adverse event (TEAE). The TEAEs noted more frequently in PP3M-vs. placebo (DB phase) were nasopharyngitis (5.6% vs. 1.4%), weight gain (8.8% vs. 3.4%), headache (8.8% vs.4.1%) and akathisia (4.4% vs. 0.7%).
Compared with placebo, PP3M significantly delayed time to first relapse in patients with schizophrenia, previously treated for 4 months with PP1M. PP3M was tolerable with a safety profile generally consistent with other marketed formulations of paliperidone.
Recent imaging studies have shown that brain morphology and neural activity during sexual arousal differ between homosexual and heterosexual men. Whether the structural and task-related functional differences also exist in the resting state is unknown. The purpose of the study is to characterize the association of homosexual preference with measures of regional homogeneity and functional connectivity in the resting state. Participants were 26 homosexual men and 26 age-matched heterosexual men. The sexual orientation of every participant was evaluated using the Kinsey Scale. We first assessed group differences in regional homogeneity and then, taking the identified differences as seed regions, we compared groups in measures of functional connectivity from those seeds. The behavioral significances of the differences in regional homogeneity and functional connectivity were assessed by examining their associations with scores on the Kinsey Scale. Homosexual participants showed significantly reduced regional homogeneity in the left inferior occipital gyrus, right middle occipital gyrus, right superior occipital gyrus, left cuneus, right precuneus, and increased regional homogeneity in the rectal gyrus, bilateral midbrain, and left temporal lobe. Regional homogeneity correlated positively with Kinsey scores in the left inferior occipital gyrus. The homosexual group also showed reduced functional connectivity in left middle temporal gyrus, left supra-marginal gyrus and right cuneus. In addition, the connection between the left inferior occipital gyrus and right thalamus in the homosexual group was correlated positively with Kinsey scores. This differences in homogeneity and fucntional connectivity may contribute to a better understanding of the neural basis of male sexual orientation.
The main aim of the present studies is to determine whether, or to some extent, specific cognitive domains could differentiate the main subtypes of mood disorder in the depressed and clinically remitted status respectively.
Three groups of bipolar I (n = 92), bipolar II (n = 131) and unipolar depression patients (n = 293) were tested with a battery of neuropsychological tests at baseline and after 6 weeks of treatment, contrasting with 202 healthy controls on cognitive performance.
At the acute depressive state, the three patients groups (bipolar I, bipolar II and unipolar depression) showed cognitive dysfunction in processing speed, memory, verbal fluency and executive function but not attention compared with controls. And post comparisons revealed that bipolar I patients performed significantly worse in these impaired cognitive domain than bipolar II and unipolar depression patients in verbal fluency and executive function. After treatment, clinically remitted bipolar I and bipolar II patients only displayed cognitive impairment in processing speed and visual memory in relative to controls, while remitted unipolar depression patients showed cognitive impairment in executive function in addition to processing speed and visual memory.
Bipolar I, bipolar II and unipolar depression patients have a similar pattern of cognitive impairment during the state of acute depressive episodes. At the clinically remission, still both bipolar disorder and unipolar depression patients showed cognitive deficits in processing speed and visual memory, and executive dysfunction might be a status-maker for bipolar disorder, but a trait-marker for unipolar depression
The main aim of this study is to investigate the capacity of a number of variables from four dimensions (clinical, psychosocial, cognitive and genetic domains) to predict the antidepressant treatment outcome, and combined the predictors in one integrate regression model with the aim to investigate which predictor contributed most.
In a semi-naturalistic prospective cohort study with a total of 241 fully assessed MDD patients, decrease in HAM-D scores from baseline to after 6 weeks of treatment was used to measure the antidepressant treatment outcome.
The clinical and psychosocial model (R2 = 0.451) showed that HAM-D scores at baseline and MMPI-2 scale paranoia was the best clinical and psychosocial predictor of treatment outcome respectively. The cognitive model (R2 = 0.502) revealed that combination of better performance on TMT-B test and worse performance on TOH and WAIS-R Digit Backward testes could predict decline in HAM-D scores. The genetics analysis only found median of percent improvement in HAM-D scores in G-allele of GR gene BclI polymorphism carriers (72.2%) was significant lower than that in non-G allele carriers (80.1%). The integrate model showed that three predictors, combination of HAM-D scores at baseline, MMPI-2 scale paranoia and TMT-B test, explained 57.1% of the variance.
Three markers, HAM-D scores at baseline, MMPI-2 scale paranoia and TMT-B test, might serve as predictor of antidepressant outcome in daily psychiatric practice.
Antipsychotic drugs (APDs) are the first-line pharmacological treatments for schizophrenia. Recent human studies have found that myelin integrity could be improved by APD treatment in schizophrenia patients. Previous studies indicated that regulation of oligodendrocyte development and function may be a novel target for APDs.
The aim of this current study was to examine the possible effects of the antipsychotic drugs (APDs) haloperidol (HAL), olanzapine (OLA), and quetiapine (QUE) on the development of oligodendroglial lineage cells.
CG4 cells, an oligodendrocyte progenitor cell line, were treated with various concentrations of HAL, OLA, or QUE for specific periods. The proliferation and differentiation of the CG4 cells were measured. The regulation of CG4 cell differentiation by oligodendrocyte lineage transcription factors 1 and 2 (Olig1 and Olig2) was examined.
The APDs used in this study had no effect on the proliferation of CG4 cells. The APDs elevated the expression of 2’,3’-cyclic nucleotide 3’-phosphodiesterase (CNP), a specific marker of oligodendrocytes, and promoted the CG4 cells to differentiate into CNP positive oligodendrocytes. QUE and OLA increased the expression of Olig1 and Olig2 whereas HAL only increased the expression of Olig2.
Our findings suggest that oligodendrocyte development is a target of HAL, OLA, and QUE and provide further evidence of the important role of oligodendrocytes in the pathophysiology and treatment of schizophrenia. They also indicate that the expression level of oligodendrocyte/myelinrelated genes could be profoundly affected by APDs.