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.
To investigate the influences of dietary riboflavin (RF) addition on nutrient digestion and rumen fermentation, eight rumen cannulated Holstein bulls were randomly allocated into four treatments in a repeated 4 × 4 Latin square design. Daily addition level of RF for each bull in control, low-RF, medium-RF and high-RF was 0, 300, 600 and 900 mg, respectively. Increasing the addition level of RF, dry matter (DM) intake was not affected, average daily gain tended to be increased linearly and feed conversion ratio decreased linearly. Total-tract digestibilities of DM, organic matter, crude protein (CP) and neutral detergent fibre (NDF) increased linearly. Rumen pH decreased quadratically and total volatile fatty acids (VFA) increased quadratically. Acetate molar percentage and acetate to propionate ratio increased linearly, but propionate molar percentage and ammonia-N content decreased linearly. Rumen effective degradability of DM increased linearly, NDF increased quadratically but CP was unaltered. Activity of cellulase and populations of total bacteria, protozoa, fungi, dominant cellulolytic bacteria, Prevotella ruminicola and Ruminobacter amylophilus increased linearly. Linear increase was observed for urinary total purine derivatives excretion. The data suggested that dietary RF addition was essential for rumen microbial growth, and no further increase in performance and rumen total VFA concentration were observed when increasing RF level from 600 to 900 mg/d in dairy bulls.
Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.
Multiple sclerosis (MS) is a central nervous system disorder that impacts more than 400,000 people in the U.S. The disease results in multiple functional impairments that are diverse and varied across individuals. Additonally, MS has a profound impact on community participation which, like other rehabilitation outcomes, cannot be explained on the basis of functional limitations alone. The purpose of this study was to develop and evaluate a model of community participation for people living with MS using the World Health Organization (WHO) International Classification of Functioning, Disability, and Health (ICF) framework. The model focused on the roles that personal factors have as predictors of community participation, while also serving as mediators and moderators for the relationship between activity limitation and participation. Results from the hierarchical regression analysis indicated that demographic characteristics (i.e. MS type), personal factors (i.e. core self-evaluations (CSE), MS self-management, resilience, and social skills), and activity limitations accounted for 64% of the variance in participation. Further, mediation analysis indicated that CSE mediated the relationship between activity limitation and community participation. Finally, moderation analysis indicated an interaction effect between educational attainment and MS self-management. Implications for future research in rehabilitation and clinical application are discussed.
Multi-dimensional aerodynamic database technology is widely used, but its model often has the curse of dimensionality. In order to solve this problem, we need projection to reduce the dimension. In addition, due to the lack of traditional method, we have improved the traditional flow field reconstruction method based on artificial neural networks, and we proposed an array neural network method.
In this paper, a set of flow field data for the target problem of the fixed Mach number is obtained by the existing CFD method. Then we arrange all the sampled flow field data into a matrix and use proper orthogonal decomposition (POD) to reduce the dimension, whose size is determined by the first few modals of energy. Therefore, significantly reduced data are obtained. Then we use an arrayed neural network to map the flow field data of simplified target problem and the flow field characteristics. Finally, the unknown flow field data can be effectively predicted through the flow field characteristic and the trained array neural network.
At the end of this paper, the effectiveness of the method is verified by airfoil flow fields. The calculation results show that the array neural network can reconstruct the flow field of the target problem more accurately than the traditional method, and its convergence speed is significantly faster. In addition, for the case of high angle flow field, the array neural network also performs well. There are no obvious jumps, and huge errors are found in results. In general, the proposed method is better than the traditional method.
Non-medical opioid use (NMOU) is a growing crisis. Cancer patients at elevated risk of NMOU (+risk) are frequently underdiagnosed. The aim of this paper was to develop a nomogram to predict the probability of +risk among cancer patients receiving outpatient supportive care consultation at a comprehensive cancer center.
3,588 consecutive patients referred to a supportive care clinic were reviewed. All patients had a diagnosis of cancer and were on opioids for pain. All patients were assessed using the Edmonton Symptom Assessment Scale (ESAS), Screener and Opioid Assessment for Patients with Pain (SOAPP-14), and CAGE-AID (Cut Down-Annoyed-Guilty-Eye Opener) questionnaires. “+risk” was defined as an SOAPP-14 score of ≥7. A nomogram was devised based on the risk factors determined by the multivariate logistic regression model to estimate the probability of +risk.
731/3,588 consults were +risk. +risk was significantly associated with gender, race, marital status, smoking status, depression, anxiety, financial distress, MEDD (morphine equivalent daily dose), and CAGE-AID score. The C-index was 0.8. A nomogram was developed and can be accessed at https://is.gd/soappnomogram. For example, for a male Hispanic patient, married, never smoked, with ESAS scores for depression = 3, anxiety = 3, financial distress = 7, a CAGE score of 0, and an MEDD score of 20, the total score is 9 + 9+0 + 0+6 + 10 + 23 + 0+1 = 58. A nomogram score of 58 indicates the probability of +risk of 0.1.
Significance of results
We established a practical nomogram to assess the +risk. The application of a nomogram based on routinely collected clinical data can help clinicians establish patients with +risk and positively impact care planning.
Toxoplasma gondii rhoptry protein TgROP18 is a polymorphic virulence effector that targets immunity-related GTPases (IRGs) in rodents. Given that IRGs are uniquely diversified in rodents and not in other T. gondii intermediate hosts, the role of TgROP18 in manipulating non-rodent cells is unclear. Here we show that in human cells TgROP18I interacts with the interferon-gamma-inducible protein N-myc and STAT interactor (NMI) and that this is a property that is unique to the type I TgROP18 allele. Specifically, when expressed ectopically in mammalian cells only TgROP18I co-immunoprecipitates with NMI in IFN-γ-treated cells, while TgROP18II does not. In parasites expressing TgROP18I or TgROP18II, NMI only co-immunoprecipitates with TgROP18I and this is associated with allele-specific immunolocalization of NMI on the parasitophorous vacuolar membrane (PVM). We also found that TgROP18I reduces NMI association with IFN-γ-activated sequences (GAS) in the IRF1 gene promoter. Finally, we determined that polymorphisms in the C-terminal kinase domain of TgROP18I are required for allele-specific effects on NMI. Together, these data further define new host pathway targeted by TgROP18I and provide the first function driven by allelic differences in the highly polymorphic ROP18 locus.
Coated copper sulphate (CCS) could be used as a Cu supplement in cows. To investigate the influences of copper sulphate (CS) and CCS on milk performance, nutrient digestion and rumen fermentation, fifty Holstein dairy cows were arranged in a randomised block design to five groups: control, CS addition (7·5 mg Cu/kg DM from CS) or CCS addition (5, 7·5 and 10 mg Cu/kg DM from CCS, respectively). When comparing Cu source at equal inclusion rates (7·5 mg/kg DM), cows receiving CCS addition had higher yields of fat-corrected milk, milk fat and protein; digestibility of DM, organic matter (OM) and neutral-detergent fibre (NDF); ruminal total volatile fatty acid (VFA) concentration; activities of carboxymethyl cellulase, cellobiase, pectinase and α-amylase; populations of Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes; and liver Cu content than cows receiving CS addition. Increasing CCS addition, DM intake was unchanged, yields of milk, milk fat and protein; feed efficiency; digestibility of DM, OM, NDF and acid-detergent fibre; ruminal total VFA concentration; acetate:propionate ratio; activity of cellulolytic enzyme; populations of total bacteria, protozoa and dominant cellulolytic bacteria; and concentrations of Cu in serum and liver increased linearly, but ruminal propionate percentage, ammonia-N concentration, α-amylase activity and populations of Prevotella ruminicola and Ruminobacter amylophilus decreased linearly. The results indicated that supplement of CS could be substituted with CCS and addition of CCS improved milk performance and nutrient digestion in dairy cows.
Guanidinoacetic acid (GAA) can improve the growth performance of bulls. This study investigated the influences of GAA addition on growth, nutrient digestion, ruminal fermentation and serum metabolites in bulls. Forty-eight Angus bulls were randomly allocated to experimental treatments, that is, control, low-GAA (LGAA), medium-GAA (MGAA) and high-GAA (HGAA), with GAA supplementation at 0, 0.3, 0.6 and 0.9 g/kg DM, respectively. Bulls were fed a basal diet containing 500 g/kg DM concentrate and 500 g/kg DM roughage. The experimental period was 104 days, with 14 days for adaptation and 90 days for data collection. Bulls in the MGAA and HGAA groups had higher DM intake and average daily gain than bulls in the LGAA and control groups. The feed conversion ratio was lowest in MGAA and highest in the control. Bulls receiving 0.9 g/kg DM GAA addition had higher digestibility of DM, organic matter, NDF and ADF than bulls in other groups. The digestibility of CP was higher for HGAA than for LGAA and control. The ruminal pH was lower for MGAA, and the total volatile fatty acid concentration was greater for MGAA and HGAA than for the control. The acetate proportion and acetate-to-propionate ratio were lower for MGAA than for LGAA and control. The propionate proportion was higher for MGAA than for control. Bulls receiving GAA addition showed decreased ruminal ammonia N. Bulls in MGAA and HGAA had higher cellobiase, pectinase and protease activities and Butyrivibrio fibrisolvens, Prevotella ruminicola and Ruminobacter amylophilus populations than bulls in LGAA and control. However, the total protozoan population was lower for MGAA and HGAA than for LGAA and control. The total bacterial and Ruminococcus flavefaciens populations increased with GAA addition. The blood level of creatine was higher for HGAA, and the activity of l-arginine glycine amidine transferase was lower for MGAA and HGAA, than for control. The blood activity of guanidine acetate N-methyltransferase and the level of folate decreased in the GAA addition groups. The results indicated that dietary addition of 0.6 or 0.9 g/kg DM GAA improved growth performance, nutrient digestion and ruminal fermentation in bulls.
We examined whether breakfast frequency was associated with chronic inflammatory, as assessed by high-sensitivity C-reactive protein (CRP) concentration.
Kailuan community, China.
Included were 70 092 Chinese adults without CVD and cancer in 2014 with CRP concentrations <10 mg/l, when breakfast frequency was assessed via a questionnaire, and plasma CRP concentration was measured.
Breakfast frequency was associated with CRP concentration (P-trend < 0·001). The adjusted mean CRP was 1·33 mg/l (95 % CI 1·23, 1·44) for the ‘no breakfast’ group and 1·07 mg/l (95 % CI 1·0, 1·14) for the ‘breakfast everyday’ group (P-difference < 0·001), adjusting for age, sex, diet quality, total energy, obesity, education, occupation, marital status, smoking, alcohol consumption, blood pressure, sleep parameters, fasting blood glucose and lipid profiles. Consistently, the adjusted OR for CRP ≥ 1·0 mg/l and CRP ≥ 3·0 mg/l were 1·86 (95 % CI 1·73, 2·00) and 1·27 (95 % CI 1·15, 1·40), respectively, when comparing these two breakfast consumption groups (P-trend < 0·001 for both). The associations were more pronounced among older adults, relative to those who were younger (P-interaction < 0·001). Significant association between breakfast skipping and elevated CRP concentration was observed in those with poor diet quality, but not those with good diet quality.
Habitually skipping breakfast was associated with elevated concentrations of CRP. Future prospective studies including repeated assessment of inflammatory biomarkers and a collection of detailed information on type and amount of breakfast foods are warranted.
Reducing dietary CP content is an effective approach to reduce animal nitrogen excretion and save protein feed resources. However, it is not clear how reducing dietary CP content affects the nutrient digestion and absorption in the gut of ruminants, therefore it is difficult to accurately determine how much reduction in dietary CP content is appropriate. This study was conducted to investigate the effects of reduced dietary CP content on N balance, intestinal nutrient digestion and absorption, and rumen microbiota in growing goats. To determine N balance, 18 growing wether goats (25.0 ± 0.5 kg) were randomly assigned to one of three diets: 13.0% (control), 11.5% and 10.0% CP. Another 18 growing wether goats (25.0 ± 0.5 kg) were surgically fitted with ruminal, proximate duodenal, and terminal ileal fistulae and were randomly assigned to one of the three diets to investigate intestinal amino acid (AA) absorption and rumen microbiota. The results showed that fecal and urinary N excretion of goats fed diets containing 11.5% and 10.0% CP were lower than those of goats fed the control diet (P < 0.05). When compared with goats fed the control diet, N retention was decreased and apparent N digestibility in the entire gastrointestinal tract was increased in goats fed the 10% CP diet (P < 0.05). When compared with goats fed the control diet, the duodenal flow of lysine, tryptophan and phenylalanine was decreased in goats fed the 11.5% CP diet (P < 0.05) and that of lysine, methionine, tryptophan, phenylalanine, leucine, glutamic acid, tyrosine, essential AAs (EAAs) and total AAs (TAAs) was decreased in goats fed the 10.0% CP diet (P < 0.05). When compared with goats fed the control diet, the apparent absorption of TAAs in the small intestine was increased in goats fed the 11.5% CP diet (P < 0.05) and that of isoleucine, serine, cysteine, EAAs, non-essential AAs, and TAAs in the small intestine was increased in goats fed the 10.0% CP diet (P < 0.05). When compared with goats fed the control diet, the relative richness of Bacteroidetes and Fibrobacteres was increased and that of Proteobacteria and Synergistetes was decreased in the rumen of goats fed a diet with 10.0% CP. In conclusion, reducing dietary CP content reduced N excretion and increased nutrient utilization by improving rumen fermentation, enhancing nutrient digestion and absorption, and altering rumen microbiota in growing goats.
This chapter reviews Narcissistic and Histrionic Personality Disorders (NPD, HPD) from three current perspectives. The categorical approach is exemplified in the DSM-5 Section II chapter on personality disorders. The categorical/dimensional hybrid approach is characterized by the DSM-5 Section III Alternative Model for Personality Disorders. Finally, both personality disorders are also conceptualized by purely dimensional and multidimensional models (e.g., pathological narcissism, histrionism). Integrative, interdisciplinary research and theory on NPD and pathological narcissism is expanding rapidly, providing novel clinical insights into classification, etiology, maintenance, patient presentation, and treatment. The clinical science of narcissism is robust, and its future appears quite promising. In contrast, contemporary research and theory on HPD and histrionism is scant and declining. Some have called for its elimination as a diagnostic entity. If the current trend of waning empirical and clinical interest persists, it is unlikely that HPD will be retained in future revisions of the DSM and other personality disorder classification systems.
The two commentaries reflect a long-standing dichotomy between clinically-experienced researchers who believe clinical personality science should reciprocally inform and be informed by the clinical enterprise (Ronningstam and Russell) and academic researchers who are dismissive of clinical complexity, eschew clinical contexts, and promote their preferred trait model (Weiss and Campbell). The commentary by Ronningstam and Russell reminds us that the clinical presentation and treatment of narcissism is complex and serious. The authors of this rejoinder fully agree. The commentary by Weiss and Campbell is anti-clinical in its stance and fails to effectively connect with the realities of clinical practice. The authors encourage these academic researchers to stop avoiding clinical complexity and clinical contexts, and instead, take advantage of advances in research methods, analytics, and technology to build a truly meaningful bridge between clinical personality science and practice.
Topological quantum materials are a class of compounds featuring electronic band structures, which are topologically distinct from common metals and insulators. These materials have emerged as exceptionally fertile ground for materials science research. The topologically nontrivial electronic structures of these materials support many interesting properties, ranging from the topologically protected states, manifesting as high mobility and spin-momentum locking, to various quantum Hall effects, axionic physics, and Majorana modes. In this article, we describe different topological matters, including topological insulators, Weyl semimetals, twisted graphene, and related two-dimensional Chern magnetic insulators, as well as their heterostructures. We focus on recent materials discoveries and experimental advancements of topological materials, and their heterostructures. Finally, we conclude with prospects for the discovery of additional topological materials for studying quantum processes, quasiparticles and their composites, as well as exploiting potential applications of these materials.
Fluid motion has two well-known fundamental processes: the vector transverse process characterized by vorticity, and the scalar longitudinal process consisting of a sound mode and an entropy mode, characterized by dilatation and thermodynamic variables. The existing theories for the sound mode involve the multi-variable issue and its associated difficulty of source identification. In this paper, we define the source of sound inside the fluid by the objective causality inherent in dynamic equations relevant to a longitudinal process, which naturally favours the material time-rate operator
rather than the local time-rate operator
, and describes the sound mode by inhomogeneous advective wave equations. The sources of sound physical production inside the fluid are then examined at two levels. For the conventional formulation in terms of thermodynamic variables at the first level, we show that the universal kinematic source can be condensed to a scalar invariant of the surface deformation tensor. Further, in the formulation in terms of dilatation at the second level, we find that the sound mode in viscous and heat-conducting flow has sources from rich nonlinear couplings of vorticity, entropy and surface deformation, which cannot be disclosed at the first level. Preliminary numerical demonstration of the theoretical findings is made for two typical compressible flows, i.e. the interaction of two corotating Gaussian vortices and the unsteady type IV shock/shock interaction. The results obtained in this study provide a new theoretical basis for, and physical insight into, understanding various nonlinear longitudinal processes and the interactions therein.
An increasing number of studies have described the relationship between celiac disease and schizophrenia. Based on the reported correlations and the overlapping linkage regions on 19p13, the myosin IXB gene (MYO9B) can be considered a highly relevant positional and functional candidate gene for schizophrenia. The present work was undertaken to investigate the association of the MYO9B gene with schizophrenia in a Chinese population.
A total of 329 patients with schizophrenia and 350 healthy control subjects in a Chinese population were recruited. A PCR-based RFLP protocol was applied to genotype 7 single nucleotide polymorphisms (SNPs), including rs7249490, rs7256689, rs2279007, rs8113494, rs2305767, rs1545620 and rs2305764, in the MYO9B gene to investigate their association with schizophrenia.
The X2 goodness-of-fit test showed that the genotypic distributions of all 7 SNPs were in Hardy-Weinberg equilibrium in both the patient group and the control group. Disease association was shown for rs8113494 (X2=12.77, P=0.0003, OR=1.89, 95% CI 1.33-2.68) and rs1545620 (X2=15.44, P=8.379e-5, OR=1.65, 95% CI 1.29-2.12), while rs2279007 was associated with schizophrenia in the female subjects (X2=4.637, P=0.031, OR=0.69, 95% CI 0.49-0.97) but not in the male subjects (X2=1.082, P=0.299, OR=0.85, 95% CI 0.63-1.15).
The present work shows that the polymorphisms of the MYO9B gene are likely to confer susceptibility to schizophrenia. Because the MYO9B gene has been found to be highly expressed in the tight junction gate, it could be considered as a meeting point for the interaction between environmental and genetic factors in the pathogenesis of schizophrenia.
An increasing number of studies have described the relationship between velo-cardio-facial syndrome (VCFS) and schizophrenia. in a family-based study, we found that rs10314, a single nucleotide polymorphism (SNP) present in the 3’-flanking region of the CLDN5 gene, was associated with schizophrenia among a Chinese population. High false positive rate is a common problem with the association study of human diseases. It is very important to replicate an initial finding with different samples and experimental designs.
A total of 749 patients with schizophrenia and 383 age and sex matched healthy control subjects in Chinese population were recruited. PCR-based RFLP protocol was applied to genotype rs10314 to see its disease association.
The χ2 goodness-of-fit test showed that the genotypic distributions of rs10314 were in Hardy-Weinberg equilibrium in both the patient group (χ2=1.12, P=0.289) and the control group (χ2=0.22, P=0.639). rs10314 was associated with schizophrenia with an odds ratio (OR) of 1.32 in the male subjects (χ2=5.45, P=0.02, 95% CI 1.05-1.67) but not in the female subjects (χ2=0.64, P=0.425, OR=1.14, 95% CI 0.83-1.57). the χ2 test showed a genotypic association only for combined samples (χ2=7.80, df=2, P=0.02). SNP rs10314 is a G to C base change. Frequency of the genotypes containing the C allele was significantly higher in the patient group than in the control group.
The present work shows that the CLDN5 gene polymorphism is more likely to be involved in schizophrenic men than women, suggesting that this gene may contribute to the gender differences in schizophrenia.
Post-stroke depression (PSD) is the most common psychiatric complication facing stroke survivors and has been associated with increased distress, physical disability, poor rehabilitation, and suicidal ideation. However, the pathophysiological mechanisms underlying PSD remain unknown, and no objective laboratory-based test is available to aid PSD diagnosis or monitor progression.
Here, an isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic approach was performed to identify differentially expressed proteins in plasma samples obtained from PSD, stroke, and healthy control subjects.
The significantly differentiated proteins were primarily involved in lipid metabolism and immunoregulation. Six proteins associated with these processes – apolipoprotein A-IV (ApoA-IV), apolipoprotein C-II (ApoC-II), C-reactive protein (CRP), gelsolin, haptoglobin, and leucine-rich alpha-2-glycoprotein (LRG) – were selected for Western blotting validation. ApoA-IV expression was significantly upregulated in PSD as compared to stroke subjects. ApoC-II, LRG, and CRP expression were significantly downregulated in both PSD and HC subjects relative to stroke subjects. Gelsolin and haptoglobin expression were significantly dysregulated across all three groups with the following expression profiles: gelsolin, healthy control > PSD > stroke subjects; haptoglobin, stroke > PSD > healthy control.
Early perturbation of lipid metabolism and immunoregulation may be involved in the pathophysiology of PSD. The combination of increased gelsolin levels accompanied by decreased haptoglobin levels shows promise as a plasma-based diagnostic biomarker panel for detecting increased PSD risk in post-stroke patients.
Several questions still exist in the literature on the relationship between cumulative exposure to work-related incidents and posttraumatic stress disorder (PTSD) in First Responders (FR).
To address three unanswered questions in the field.
(1) Are different cumulative exposure scoring algorithms similarly related to PTSD?
(2) Is PTSD associated only with incidents rated as severe and traumatic?
(3) Can we identify cut-off scores of cumulative exposure that maximize sensitivity and specificity to predict PTSD?
To better characterize the relationship between cumulative exposure and PTSD in FR.
The association between exposure and PTSD was examined with logistic and linear regression and with receiver operating characteristic analysis in 349 FR.
(1) The strength of the association between PTSD and total cumulative exposure indexes varied across different scoring algorithms.
(2) Compared to total cumulative exposure indexes and to sub-scores of exposure to non-traumatic and/or less severe incidents, sub-scores indexing exposure to severe traumatic events only were more strongly and significantly associated with PTSD.
(3) The use of two cut-off scores maximizes sensitivity and specificity to predict PTSD.
(1) The relationship between current PTSD and cumulative exposure is partially dependent on the approach used to quantify exposure.
(2) Focusing on the assessment of cumulative exposure to severe traumatic events is sufficient to predict PTSD, and might be more useful and effective in research and clinical decision-making.
(3) Sensitivity and specificity of exposure scores might help improve secondary prevention (early detection and effective intervention) of individuals at risk.
The heterogeneity in the manifestation of PSTD symptomatology has never been described in a developmental period spanning from middle childhood through adolescence. The examination of developmental influences on PTSD symptomatic expression is a high priority for DSM-V and could inform research on the etiology and treatment of PTSD.
To examine the symptom structure of PTSD across different age, gender, and exposure groups, and in association with impairment and other disorders.
To identify homogeneous latent classes of PTSD symptoms in children and adolescents.
Latent class analysis (LCA) was applied to 6,733 New York City students (4th–12th grades) exposed to 9/11-related potentially traumatic events. LCA was first applied to PTSD symptoms only, stratified by age, gender and empirically defined exposure groups, and then in combination with impairment indicators. The resultant classes were studied in association with other disorders.
LCA identified 4 classes that vary in severity and symptom configuration. Only the most severe profile, qualitatively characterized by the presence of traumatic memories in combination with avoidance and sleep-related problems, showed high levels of impairment and high rates of other disorders. Girls after puberty and subjects indirectly exposed to 9/11 are at increased risk of severe disturbance.
The 4-class model describes quantitative and qualitative differences in the structure of PTSD across age, gender and exposure. These findings support the inclusion of developmental considerations into DSM-V PTSD diagnostic criteria and suggest that also gender and the nature of traumatic exposure inflence PTSD phenomenology in children and adolescents.