To send 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 sending content to .
To send 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 sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent 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 well-established and acclaimed textbook introducing the rapidly growing field of nerve and muscle function has been completely revised and updated. Written with undergraduate students in mind, it begins with the fundamental principles demonstrated by the pioneering electrophysiological experiments on cell excitability. This leads to more challenging material recounting recent discoveries from applying modern biochemical, genetic, physiological and biophysical, experimental and mathematical analysis. The resulting interdisciplinary approach conveys a unified contemporary understanding of nerve and skeletal, cardiac and smooth muscle function at the molecular, cellular and systems levels. Emphasis on important strategic experiments throughout clarifies the basis for our current scientific views, highlights the excitement and challenge of biomedical discovery, and suggests directions for future advances. These fundamental ideas are then translated into discussions of related disease conditions and their clinical management. Now including colour illustrations, it is an invaluable text for students of physiology, neuroscience, cell biology and biophysics.
Family coaggregation of attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), bipolar disorder (BD), major depressive disorder (MDD) and schizophrenia have been presented in previous studies. The shared genetic and environmental factors among psychiatric disorders remain elusive.
This nationwide population-based study examined familial coaggregation of major psychiatric disorders in first-degree relatives (FDRs) of individuals with ASD. Taiwan's National Health Insurance Research Database was used to identify 26 667 individuals with ASD and 67 998 FDRs of individuals with ASD. The cohort was matched in 1:4 ratio to 271 992 controls. The relative risks (RRs) and 95% confidence intervals (CI) of ADHD, ASD, BD, MDD and schizophrenia were assessed among FDRs of individuals with ASD and ASD with intellectual disability (ASD-ID).
FDRs of individuals with ASD have higher RRs of major psychiatric disorders compared with controls: ASD 17.46 (CI 15.50–19.67), ADHD 3.94 (CI 3.72–4.17), schizophrenia 3.05 (CI 2.74–3.40), BD 2.22 (CI 1.98–2.48) and MDD 1.88 (CI 1.76–2.00). Higher RRs of schizophrenia (4.47, CI 3.95–5.06) and ASD (18.54, CI 16.18–21.23) were observed in FDRs of individuals with both ASD-ID, compared with ASD only.
The risk for major psychiatric disorders was consistently elevated across all types of FDRs of individuals with ASD. FDRs of individuals with ASD-ID are at further higher risk for ASD and schizophrenia. Our results provide leads for future investigation of shared etiologic pathways of ASD, ID and major psychiatric disorders and highlight the importance of mental health care delivered to at-risk families for early diagnoses and interventions.
We exploit the expiring nature of hedge fund lockups to create a new measure of funding liquidity risk that varies within funds. We find that hedge funds with lower funding risk generate higher returns, and this effect is driven by their increased exposure to equity-mispricing anomalies. Our results are robust to a variety of sampling criteria, variable definitions, and control variables. Further, we address endogeneity concerns in various ways, including a placebo approach and regression discontinuity design. Collectively, our results support a causal link between funding risk and the ability of managers to engage in risky arbitrage.
Daytime sleepiness is associated with multiple negative outcomes in older adults receiving long-term services and supports (LTSS) including reduced cognitive performance, need for greater assistance with activities of daily living and decreased social engagement. The purpose of this study was to identify predictors of change in subjective daytime sleepiness among older adults during their first 2 years of receiving LTSS.
Design and Setting:
Secondary analysis of data from a prospective longitudinal study of older adults who received LTSS in their homes, assisted living communities or nursing homes interviewed at baseline and every 3 months for 24 months.
470 older adults (60 years and older) newly enrolled in LTSS (mean = 81, SD = 8.7; range 60–98; 71% women).
Subjective daytime sleepiness was assessed every 3 months through 2 years using the Epworth Sleepiness Scale. Multiple validated measures were used to capture health-related quality of life characteristics of enrollees and their environment, including symptom status (Symptom Bother Scale), cognition (Mini Mental Status Exam), physical function (Basic Activities of Daily Living), physical and mental general health, quality of life (Dementia Quality of Life, D-QoL), depressive symptoms (Geriatric Depression Scale) and social support (Medical Outcomes Survey-Social Support).
Longitudinal mixed effects modeling was used to examine the relationship between independent variables and continuous measure of daytime sleepiness. Increased feelings of belonging, subscale of the D-QoL (effect size = −0.006, 95% CI: −0.013 to −0.0001, p = 0.045) and higher number of depressive symptoms (effect size = −0.002, 95% CI: −0.004 to −0.001, p = 0.001) at baseline were associated with slower rates of increase in daytime sleepiness over time.
Comprehensive baseline and longitudinal screening for changes in daytime sleepiness along with depression and perceived quality of life should be used to inform interventions aimed at reducing daytime sleepiness among older adults receiving LTSS.
Surface waves called meniscus waves often appear in systems that are close to the capillary length scale. Since the meniscus shape determines the form of the meniscus waves, the resulting streaming circulation has features distinct from those caused by other capillary–gravity waves recently reported in the literature. In the present study, we produce symmetric and antisymmetric meniscus shapes by controlling boundary wettability and excite meniscus waves by oscillating the meniscus vertically. The symmetric and antisymmetric configurations produce different surface capillary–gravity wave modes and streaming flow structures. The root-mean-square speed of the streaming circulation increases with the second power of the forcing amplitude in both configurations. The flow symmetry of streaming circulation is retained under the symmetric meniscus, while it is lost under the antisymmetric meniscus. The streaming circulation pattern beneath the meniscus observed in our experiments is qualitatively explained using the method introduced by Nicolás & Vega (Fluid Dyn. Res., vol. 32 (4), 2003, pp. 119–139) and Gordillo & Mujica (J. Fluid Mech., vol. 754, 2014, pp. 590–604).
Introduction: Selecting appropriate patients for hospitalization following emergency department (ED) evaluation of syncope is critical for serious adverse event (SAE) identification. The primary objective of this study is to determine the association of hospitalization and SAE detection using propensity score (PS) matching. The secondary objective was to determine if SAE identification with hospitalization varied by the Canadian Syncope Risk Score (CSRS) risk-category. Methods: This was a secondary analysis of two large prospective cohort studies that enrolled adults (age ≥ 16 years) with syncope at 11 Canadian EDs. Patients with a serious condition identified during index ED evaluation were excluded. Outcome was a 30-day SAE identified either in-hospital for hospitalized patients or after ED disposition for discharged patients and included death, ventricular arrhythmia, non-lethal arrhythmia and non-arrhythmic SAE (myocardial infarction, structural heart disease, pulmonary embolism, hemorrhage). Patients were propensity matched using age, sex, blood pressure, prodrome, presumed ED diagnosis, ECG abnormalities, troponin, heart disease, hypertension, diabetes, arrival by ambulance and hospital site. Multivariable logistic regression assessed the interaction between CSRS and SAE detection and we report odds ratios (OR). Results: Of the 8183 patients enrolled, 743 (9.0%) patients were hospitalized and 658 (88.6%) were PS matched. The OR for SAE detection for hospitalized patients in comparison to those discharged from the ED was 5.0 (95%CI 3.3, 7.4), non-lethal arrhythmia 5.4 (95%CI 3.1, 9.6) and non-arrhythmic SAE 6.3 (95%CI 2.9, 13.5). Overall, the odds of any SAE identification, and specifically non-lethal arrhythmia and non-arrhythmia was significantly higher in-hospital among hospitalized patients than those discharged from the ED (p < 0.001). There were no significant differences in 30-day mortality (p = 1.00) or ventricular arrhythmia detection (p = 0.21). The interaction between ED disposition and CSRS was significant (p = 0.04) and the probability of 30-day SAEs while in-hospital was greater for medium and high risk CSRS patients. Conclusion: In this multicenter prospective cohort, 30-day SAE detection was greater for hospitalized compared with discharged patients. CSRS low-risk patients are least likely to have SAEs identified in-hospital; out-patient monitoring for moderate risk patients requires further study.
White matter abnormalities have been repeatedly reported in both schizophrenia and bipolar disorder (BD) diseases from diffusion tensor imaging (DTI) studies respectively, while the empirical evidences about the diagnostic specificity of white matter abnormalities in these disorders are still limited.
25 patients with paranoid schizophrenia and 18 patients with bipolar mania were recruited from the in-patient unit of the Mental Health Centre, West China Hospital, China.
Patients were diagnosed according to the criteria of Diagnostic and Statistical Manual of Mental Disorders-Version IV (DSM- IV). 30 healthy controls were recruited from the community by means of leaflets distributed throughout Chengdu city.
This study sought to investigate the alterations in fractional anisotropy (FA) in white matter throughout the entire brain of patients from Chengdu, China with paranoid schizophrenia and bipolar mania.
Diffusion tensor imaging (DTI) was used to assess white matter integrity in patients with paranoid schizophrenia and bipolar mania, as well as in normal controls. The differences in FA were measured by use of voxel-based analysis.
Reduced FA was found in the left posterior corona radiate (PCR) in patients with bipolar mania and paranoid schizophrenia compared to the controls. Patients with bipolar mania also showed a significant reduction in FA in right posterior corona radiate and in right anterior thalamic radiation (ATR).
Common abnormalities in the left PCR might imply an overlap in white matter pathology of both diseases and might be related to the shared risk factors for both disorders.
To explore the clinical characteristics, assessment, biological and psychosocial correlates, and treatment of pediatric bipolar disorder (BD) in China.
All the studies published during the past 20 years on pediatric bipolar disorder in China were reviewed.
There is a lack of a unified diagnosis system in China. A serial of genetic researches showed the family aggregation and genetic predisposition of BD. There are consistent findings on the core symptoms of the disorder. BD has the characteristic of comorbidity with other disorders such as ADHD and OCD. Mood stabilizers and combined use of antipsychotics and TCA are still the main choice of psychiatrists to treat the pediatric patients with BD. The effectiveness of specific psychotherapy does need further studies.
A unified diagnosis system and criteria of BD for different age groups is crucial for further work. Combination of various treatments, such as mood stabilizers, AC, TCA and traditional Chinese medicine is effective for these patients. More studies, especially randomized controlled trials should be conducted to explore the etiology, pharmacotherapy and psychotherapy of this disease.
Although the deviations of brain volume deficits in sporadic and familial first-episode schizophrenia patients (FEP) had been presented, the difference of brain asymmetries remained unidentified.
To assess the potential differences of volumetric asymmetries of gray matter (GM) and white matter (WM) between groups.
To find out the different injury alteration of sporadic FEP and familial FEP.
42 sporadic and 30 familiar drug-naïve FEP with and 72 matched normal controls (NC) were recruited. Participants were assessed with neuropsychological tests and scanned by a 3.0T MRI to obtain T1-weighted and DTI images. Lateralization distribution maps of GM and WM volume were generated by employing optimized voxel-based morphometry. The asymmetries were analyzed by comparing calculating Laterality Index (LI) voxel by voxel.
All three groups showed similar overall brain torque. Familiar FEP have more regional extensive GM asymmetry brain lesions compared to sporadic FEP. There was no shared regional lesion between two groups. LIGM and LIWM in right superior temporal were negatively correlated. Significant negative correlations were also found between LIGM of left superior parietal lobule and LIWM of right superior parietal lobule, and between LIGM of right inferior parietal lobule and LIWM of left inferior parietal lobule. The asymmetry in distinct brain regions were related to cognitive deficits especially in the domains of language and memory.
The two patient groups had different alteration in injuries of brain asymmetry. Familiar FEP has more GM extensive asymmetry brain region, which may correlate with their high genetic burdens.
Despite strong evidence that the pathophysiology of tic disorders (TD) involves structural and functional disturbances of the basal ganglia, inconsistent findings from several TD imaging studies have supported contradictory conclusions.
To find brain structural differences between children with of TD and the health children and verify the pathogenesis hypothesis of that basal ganglia play an important role in this disorder.
The right handedness, first-episode TD children were chosen. Yale global tic severity scale (YGTSS) was used to assess the tic severity. MRI scan was performed on TD children and the controls. The volumes of caudate nucleus, putamen, globus pallidus and total intracranial volume were measured on high resolution MR images. We compared the volumes, relative volumes and asymmetry index, AI between groups.
Totally 11 patients finished this study with two excluded for the unclear image caused by tic and 18 subjects (9 TD patients and 9 controls) were finally analyzed. The right globus pallidus is significantly larger in TD patients. The volumes of left caudate increased significantly in both TD patients and controls. There was no significant difference in asymmetry index between two groups, relative volumes did not correlate significantly with the severity of tic and the course of disease.
The right globus pallidus may be the primary pathological change of TD. Asymmetry indexes between the two groups are not significantly different. The relative volume of any structure of basal ganglia has no significant correlation with the severity of tic and the course of disease.
Increasing evidence indicates that major depressive disorder (MDD) is associated with cognitive as well as mood disturbances.
To evaluate cognitive function and white matter structure, resting-state brain function in first-episode, treatmentnaive patients with MDD.
To explore brain structure and function mechanisms of cognitive impairment in MDD.
46 Han Chinese MDD patients aged 18–45 year and 46 controls were assessed by a series of validated test procedures.Then, 30 patients and 30 controls were obtained by MRI scan.White matter abnormalities evaluated using diffusion tensor imaging (DTI) were analyzed using tract based spatial statistics (TBSS) and resting-state brain function was evaluated using regional homogeneity (ReHo) analysis.
Cognitive impairment in patients with MDD was demonstrated by reduced accuracy in the Wisconsin Card Sorting test (WSCT) and to a lesser extent the Continuous Performance test (CPT) and Trail Making tests (TMT). White matter abnormalities found in the left cerebellum, and resting-state abnormalities present in the left inferior parietal gyrus, left anterior cingulate nucleus and left hippocampal gyrus were associated with impaired performance in the WSCT and CPT tests. We also showed that poor WSCT performance was associated with increased interconnectivity between the left ventral anterior cingulate nucleus and the medial frontal lobe areas.
The present study indicates cognitive disturbances in patients with MDD are associated with white matter and resting-state changes and altered interconnections in specific brain areas.
Postoperative nausea and vomiting (PONV) is the most common postoperative complication after gynecological laparoscopic surgery. It is unknown whether the occurrence of PONV is associated with the preoperative psychological status.
To explore the effects of preoperative psychological status on the incidence of PONV following gynecological laparoscopic surgery.
To analyze the possible risk factors in order to prevent and treat PONV after gynecological laparoscopic surgery.
101 cases patients who underwent gynecological laparoscopic surgery were enrolled. Self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were used to assess the preoperative psychological state. Visual analog scale nausea (NVAS) was used to evaluate the occurrence of PONY within the postoperative 24 hours.
101 patients completed NVAS and 72 patients completed SAS and SDS. The incidence of PONV was 45.5%. The standard score of SAS (49.14±8.01) in PONV group was significantly higher than that in Non-PONV group (44.54±7.58) t=2.505, P < 0.05. The ratio of preoperative anxiety patients(SAS≥50) in PONV group(57%) was higher than that in Non-PONV group (30%) (χ2=5.513, P < 0.05). It showed that the occurrence of PONV was positively correlated with preoperative anxiety (r=0.277, P < 0.05). There was no difference in the scores of SDS between two groups. No correlation was found between PONV and preoperative depression.
Higher level of anxiety before surgery may increase the risk of PONV. The patients undergoing gynecological laparoscopic surgery should reduce the level of anxiety with appropriate psychological counseling or prophylactic anti-anxiety drugs.
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.
The presence of comorbid anxiety disorders (AD) and bipolar II disorders (BP-II) compounds disability complicates treatment, worsens prognosis, and has been understudied. The genes involved in metabolizing dopamine and encoding dopamine receptors, such as aldehyde dehydrogenase 2 (ALDH2) and dopamine D2 receptor (DRD2) genes, may be important to the pathogenesis of BP-II comorbid with AD. We aimed to clarify ALDH2 and DRD2 genes for predisposition to BP-II comorbid with and without AD. The sample consisted of 335 subjects BP-II without AD, 127 subjects BP-II with AD and 348 healthy subjects as normal control. The genotypes of the ALDH2 and DRD2 Taq-IA polymorphisms were determined using polymerase chain reactions plus restriction fragment length polymorphism analysis. Logistic regression analysis showed a statistically significant association between DRD2 Taq-I A1/A2 genotype and BP-II with AD (OR = 2.231, P = 0.021). Moreover, a significant interaction of the DRD2 Taq-I A1/A1 and the ALDH2*1*1 genotypes in BP-II without AD was revealed (OR = 5.623, P = 0.001) compared with normal control. Our findings support the hypothesis that a unique genetic distinction between BP-II with and without AD, and suggest a novel association between DRD2 Taq-I A1/A2 genotype and BP-II with AD. Our study also provides further evidence that the ALDH2 and DRD2 genes interact in BP-II, particularly BP-II without AD.
The aim of this study was to develop and externally validate a simple-to-use nomogram for predicting the survival of hospitalised human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) patients (hospitalised person living with HIV/AIDS (PLWHAs)). Hospitalised PLWHAs (n = 3724) between January 2012 and December 2014 were enrolled in the training cohort. HIV-infected inpatients (n = 1987) admitted in 2015 were included as the external-validation cohort. The least absolute shrinkage and selection operator method was used to perform data dimension reduction and select the optimal predictors. The nomogram incorporated 11 independent predictors, including occupation, antiretroviral therapy, pneumonia, tuberculosis, Talaromyces marneffei, hypertension, septicemia, anaemia, respiratory failure, hypoproteinemia and electrolyte disturbances. The Likelihood χ2 statistic of the model was 516.30 (P = 0.000). Integrated Brier Score was 0.076 and Brier scores of the nomogram at the 10-day and 20-day time points were 0.046 and 0.071, respectively. The area under the curves for receiver operating characteristic were 0.819 and 0.828, and precision-recall curves were 0.242 and 0.378 at two time points. Calibration plots and decision curve analysis in the two sets showed good performance and a high net benefit of nomogram. In conclusion, the nomogram developed in the current study has relatively high calibration and is clinically useful. It provides a convenient and useful tool for timely clinical decision-making and the risk management of hospitalised PLWHAs.
CACNA1I (hCaV3.3) encodes the α1 pore-forming subunit of human voltage-gated T-type calcium channels. CaV3.3 is expressed in a limited subset of neurons including GABAergic neurons of the thalamic reticular nucleus (TRN) where they support oscillatory activity essential for sleep spindle generation. CACNA1I is implicated in schizophrenia risk by emerging genetics including genome-wide association studies (PGC, 2014), and exome sequencing of trio samples (Gulsuner et al., 2013). In order to understand the impact of disease-associated sequence variation on the function of CaV3.3, we set out to analyze a complete set of rare mis-sense coding variations in CACNA1I in a Swedish cohort, including 15 variations identified in patients, 20 identified in control subjects, and 23 in both. We established a heterologous expression system of isogenic cell lines, each carrying single-copy inducible cDNA variants of hCaV3.3, and evaluated their functional impact on channel function by electrophysiology, calcium imaging, and biochemistry. We found at least five coding variations impaired overall channel protein abundance, as well as whole cell current density. In addition, we identified hCaV3.3 variants with altered voltage-dependence of channel activation and inactivation. Overall, we found that reduced calcium influx through hCaV3.3 is associated with the group of variants identified in patients, compared to those in both patients and controls. Our findings suggest that patient-specific rare variations of CACNA1I may influence channel-dependent functions, including rebound bursting in TRN neurons, with potential implications for schizophrenia pathophysiology.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Glutathione S-transferases (GSTs) are a detoxifying enzyme family that is essential for parasite blood-feeding and survival, and represent potential targets for hookworm vaccine development. Multiple GST-encoding complementary DNAs (cDNAs) have been cloned from Ancylostoma caninum and Necator americanus, but there are no reports about the cloning of this enzyme from Ancylostoma ceylanicum, the animal-derived zoonotic hookworm. To study the molecular nature and tissue localization of GST of A. ceylanicum (Ace-GST), we designed primers based on the GST gene sequence of A. ceylanicum in GenBank, amplified the Ace-GST cDNA by reverse transcription polymerase chain reaction, and analysed its homology and genetic evolution relationship. The amplified product was cloned into the pET-32a vector and transformed into Escherichia coli BL21 (DE3) for expression. To prepare anti-GST polyclonal antibodies, the recombinant protein was purified and used to immunize Kunming mice. The level of immunoglobulin G (IgG) antibody in the serum of immunized mice was detected by indirect enzyme-linked immunosorbent assay, and the Ace-GST localization in adult worm was determined using the immunofluorescence method. The results showed that the full-length cDNA encoding Ace-GST was 468 bp, which had the highest homology with Ac-GST-1 (60.1%) and clustered into one branch (v-class) with Ac-GST-1 and Na-GST-1 in a phylogenetic tree. Mice immunized with recombinant Ace-GST showed specific IgG antibody response. Immunolocalization revealed that natural Ace-GST is mainly located in the epidermis, muscle and intestine of the adult. These results may lay a foundation for further studies on the biological function of Ace-GST.
Sparganosis is an important foodborne parasitic zoonosis; however, few reports on the prevalence of snake-infecting plerocercoids from Hunan province in China are available. Therefore, we investigated the prevalence of spargana infection in wild snakes from this region in 2018, and identified an astonishing prevalence rate of 91.7% (344/375). Spargana parasites were found in 99.1% of Zaocys dhumnades, 94.1% of Elaphe carinata and 86.7% of Elaphe taeniura. Parasites exhibited various distributions: 50% were located in muscular tissue, 32.1% in subcutaneous tissue and 17.9% in the coelomic cavity. To identify the specific status of spargana collected from wild snakes, partial mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences were amplified, sequenced and analysed. Sequence variations for cox1 among all the examined plerocercoids ranged between 0.0 and 2.9%, with 21 variable sites identified (4.71%, 21/446). Phylogenetic analyses identified that all plerocercoids isolated from Hunan province were Spirometra erinaceieuropaei. This is the first report of S. erinaceieuropaei infection in snakes in Hunan province. The risks and harms of sparganosis should be publicized, and illegal wildlife trade should be controlled.
Triptorelin (TRI), a gonadotropin-releasing hormone agonist allowing ovulation synchronization in pigs, is indispensable for fixed-time artificial insemination (FTAI) protocols. However, the effect of FTAI using TRI (FTAI-TRI) on the reproductive performance is controversial. We performed a meta-analysis to determine whether FTAI-TRI affects reproductive performance of pigs, including pregnancy rate (PR), number of pigs born alive per litter (NBA), farrowing rate (FR) and total number of pigs born per litter (TNB). A total of 37 trials from 15 studies were extracted and analysed in Stata. A weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for NBA and TNB, and risk ratio (RR) with 95% CI was calculated for PR and FR. Pregnancy rate, TNB and NBA data were applied to a fixed-effect protocol, and FR data were applied to a random-effect protocol. We found that for weaned sows, the FTAI-TRI group had comparable reproductive performance to the artificial insemination (AI) following oestrus detection (EDAI) group. Fixed-time AI has many advantages, including the elimination of the need to heat-check twice daily, so that FTAI-TRI is a good substitute for EDAI. Subgroup analysis indicated that the optimal timing of triptorelin treatment was 96 h after weaning, which gave significant positive effects on PR (RR = 1.08, P = 0.000) and non-significant positive effects on TNB (WMD = 0.12, P = 0.452). Triptorelin at a dose of 100 μg showed better effects than 200 μg, with significant positive effects on PR (RR = 1.09, P = 0.005) and FR (RR = 1.06, P = 0.036). So a single dose of 100 μg was recommended. The optimal protocol was insemination at 24 h and again at 48 h after triptorelin administration if they remained in standing oestrus, and this provided a significantly higher NBA (WMD = 0.59, P = 0.013) that increased by 0.59. For gilts, the FTAI-TRI group showed decreased (not significant) PR (RR = 0.96, P = 0.127) and significantly decreased FR (RR = 0.93, P = 0.013), TNB (WMD = −0.85, P = 0.006) and NBA (WMD = −0.98, P = 0.000), which were inferior to those in the EDAI group. In conclusion, the effects of FTAI-TRI on the reproductive performance of pigs were parity-, treatment timing-, insemination timing-, and dosage-dependent. Fixed-time AI using triptorelin could effectively replace the EDAI protocol for sows, but not for gilts.
Flow over aligned and staggered cube arrays is a classic model problem for rough-wall turbulent boundary layers. Earlier studies of this model problem mainly looked at rough surfaces with a moderate coverage density, i.e.
is the surface coverage density and is defined to be the ratio between the area occupied by the roughness and the total ground area. At lower surface coverage densities, i.e.
, it is conventionally thought that cubical roughness acts like isolated roughness elements; and that the single-cube drag coefficient, i.e.
is the drag force on one cubical roughness element,
is the fluid density,
is the height of the cube,
is the spatially and temporally averaged wind speed at the cube height, and
is the drag coefficient of an isolated cube. In this work, we conduct large-eddy simulations and direct numerical simulations of flow over wall-mounted cubes with very low surface coverage densities, i.e.
. The large-eddy simulations are at nominally infinite Reynolds numbers. The results challenge the conventional thinking, and we show that, at very low surface coverage densities, the single-cube drag coefficient may increase as a function of
. Our analysis suggests that this behaviour may be attributed to secondary turbulent flows. Secondary turbulent flows are often found above spanwise-heterogeneous roughness. Although the roughness considered in this work is nominally homogeneous, the secondary flows in our simulations are very similar to those observed above spanwise-heterogeneous surface roughness. These secondary vortices redistribute the fluid momentum in the outer layer, leading to high-momentum pathways above the wall-mounted cubes and low-momentum pathways at the two sides of the wall-mounted cubes. As a result, the spatially and temporally averaged wind speed at the cube height, i.e.
, is an underestimate of the incoming flow to the cubes, which in turn leads to a large drag coefficient