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After briefly reviewing the received doctrine prior to the waves of privatisations beginning in the 1980s, this Element offers a survey of various analytical frameworks on State Owned Enterprises (SOEs) from the perspective of applied welfare economics. The focus then shifts to a positive analysis of the comparative performance of private versus public enterprises, with a specific emphasis on SOEs in developed market economies over the past two decades; key metrics examined include profitability, productivity, internationalisation, innovativeness, and environmental sustainability. The Element also addresses empirical methodological issues, alongside contextual conditions and institutional factors that help explain the outcomes. It reviews selected contributions from public economics, industrial organisation, corporate governance, management studies and other social sciences. Overall, the Element aims to redefine a neglected research area in public economics, considering the new circumstances of the twenty-first century, where SOEs compete with other firms in developed market economies.
Women with schizophrenia frequently discontinue antipsychotic medications during pregnancy. However, evidence on the risk of postpartum relapse associated with antipsychotic use during pregnancy is lacking.
Aims
To investigate the within-individual association between antipsychotic continuation during pregnancy and postpartum relapse in women with schizophrenia.
Method
This retrospective cohort study used data of women with schizophrenia who gave live birth between 2007 and 2018 identified from the National Health Information Database of South Korea. Women were classified according to antipsychotic use patterns during the 12 months before delivery as non-users, discontinuers and continuers. Relapse was defined as admission for psychosis (ICD-10, F20–29). The incidence rate ratio (IRR) for admission for psychosis in the 6-month postpartum period was estimated using conditional Poisson regression, with the reference period set between 2 and 1 years before delivery. Additionally, we calculated the relative risk ratios (RRRs) for the IRRs of different antipsychotic use patterns.
Results
Among the 3026 women included in the analysis (median age 34 years, interquartile range 31–37), the within-individual risk of admission for psychosis in the 6-month postpartum period was 0.56 times (RRR, 95% CI 0.36–0.87) lower in continuers (IRR = 1.31, 95% CI 0.89–1.72) than in discontinuers (IRR = 2.34, 95% CI 1.87–2.91). Among discontinuers, the IRRs of admission for psychosis in the 6-month postpartum period did not change significantly with the timing of discontinuation (trend P = 0.946).
Conclusions
Antipsychotic continuation during pregnancy was associated with a reduced risk of postpartum relapse in women with schizophrenia. Continuing antipsychotics during pregnancy would be recommended after a risk–benefit assessment.
Many studies report on the association between 2D:4D, a putative marker for prenatal testosterone exposure, and economic preferences. However, most of these studies have limited sample sizes and test multiple hypotheses (without preregistration). In this study we mainly replicate the common specifications found in the literature for the association between the 2D:4D ratio and risk taking, the willingness to compete, and dictator game giving separately. In a sample of 330 women we find no robust associations between any of these economic preferences and 2D:4D. We find no evidence of a statistically significant relation for 16 of the 18 total regressions we run. The two regression specifications which are statistically significant have not previously been reported and the associations are not in the expected direction, and therefore they are unlikely to represent a real effect.
We propose a hierarchical Bayesian model for analyzing multi-site experimental fMRI studies. Our method takes the hierarchical structure of the data (subjects are nested within sites, and there are multiple observations per subject) into account and allows for modeling between-site variation. Using posterior predictive model checking and model selection based on the deviance information criterion (DIC), we show that our model provides a good fit to the observed data by sharing information across the sites. We also propose a simple approach for evaluating the efficacy of the multi-site experiment by comparing the results to those that would be expected in hypothetical single-site experiments with the same sample size.
We investigate the implications of penalizing incorrect answers to multiple-choice tests, from the perspective of both test-takers and test-makers. To do so, we use a model that combines a well-known item response theory model with prospect theory (Kahneman and Tversky, Prospect theory: An analysis of decision under risk, Econometrica 47:263–91, 1979). Our results reveal that when test-takers are fully informed of the scoring rule, the use of any penalty has detrimental effects for both test-takers (they are always penalized in excess, particularly those who are risk averse and loss averse) and test-makers (the bias of the estimated scores, as well as the variance and skewness of their distribution, increase as a function of the severity of the penalty).
In comparing characteristics of independent populations, researchers frequently expect a certain structure of the population variances. These expectations can be formulated as hypotheses with equality and/or inequality constraints on the variances. In this article, we consider the Bayes factor for testing such (in)equality-constrained hypotheses on variances. Application of Bayes factors requires specification of a prior under every hypothesis to be tested. However, specifying subjective priors for variances based on prior information is a difficult task. We therefore consider so-called automatic or default Bayes factors. These methods avoid the need for the user to specify priors by using information from the sample data. We present three automatic Bayes factors for testing variances. The first is a Bayes factor with equal priors on all variances, where the priors are specified automatically using a small share of the information in the sample data. The second is the fractional Bayes factor, where a fraction of the likelihood is used for automatic prior specification. The third is an adjustment of the fractional Bayes factor such that the parsimony of inequality-constrained hypotheses is properly taken into account. The Bayes factors are evaluated by investigating different properties such as information consistency and large sample consistency. Based on this evaluation, it is concluded that the adjusted fractional Bayes factor is generally recommendable for testing equality- and inequality-constrained hypotheses on variances.
This study aimed to explore the influence of laryngopharyngeal reflux on the features of vocal fold polyps and prognosis after office-based transnasal vocal fold polypectomy.
Methods
Eighty-four vocal fold polyp patients were retrospectively analysed. Patients were assigned to laryngopharyngeal reflux or non-laryngopharyngeal reflux groups using pre-operative Reflux Symptom Score-12.
Results
The laryngopharyngeal reflux group had significantly higher pre-operative Reflux Sign Assessment scores, worse lifestyle and worse eating habits than the non-laryngopharyngeal reflux group. After office-based transnasal vocal fold polypectomy, the Reflux Symptom Score-12 and Reflux Sign Assessment score decreased in both groups, although the laryngopharyngeal reflux group still had higher values. The non-laryngopharyngeal reflux group had better vocal fold morphology recovery than the laryngopharyngeal reflux group. Multivariate logistic regression analysis demonstrated that smoking and a higher pre-operative Reflux Symptom Score-12 score were independent risk factors for poor prognosis.
Conclusions
Laryngopharyngeal reflux is detrimental to vocal fold recovery of vocal fold polyp patients following office-based transnasal vocal fold polypectomy. For vocal fold polyp patients with laryngopharyngeal reflux, lifestyle and diet guidance should be focused.
Based on monthly panel data from 2014 to 2020 and employing the staggered difference-in-differences (staggered DID) method, we examine the impact of environmental vertical management reform on data manipulation in the public sector. We reveal that environmental vertical management reform significantly reduces data manipulation in the public sector. Moderating effect analysis shows that economic growth targets weaken the inhibitory impact of this reform. Conversely, public environmental concerns could enhance the inhibitory impact of this reform on data manipulation. Mechanism analysis reveals that environmental vertical management reform works through strengthening grassroots environmental law enforcement. The increased independence of law-enforcing departments has reduced the tendency of local governments to engage in data manipulation.
We study the melting process of a solid under microgravity, driven solely by lateral vibrations that are perpendicular to the applied temperature gradient due to the absence of gravity-induced convection. Using direct numerical simulations with the phase-field method, we examine two-dimensional vibration-induced melting in a square cavity over four orders of magnitude of vibrational Rayleigh numbers, $10^5\le Ra_{{vib}}\le 10^9$. Our results show that as melting progresses, the flow structure transitions from a periodic-circulation regime with diffusion-dominated heat transfer to a columnar regime with vibroconvection. The mean height of the liquid–solid interface follows a power-law dependency with time, $\bar {\xi } \sim \tilde t^{1/(2-2\alpha )}$, where $\alpha = 0$ in the periodic-circulation regime and $\alpha = 1/2$ in the columnar regime. We further observe that within the columnar regime, the morphological evolution of the liquid–solid interface is influenced by the interaction of columnar thermal plumes in the central regions and the peripheral flow near the sidewalls. Specifically, we offer a comprehensive analysis of the plume merging behaviour, which is governed by the aspect ratio ($\bar {\xi }$) of the liquid layer and the intensity of vibration, quantified by the effective vibrational Rayleigh number $Ra_{vib}^{eff}$. We identify the relationship between the number of columnar plumes $K_m$ and $Ra_{vib}^{eff}$, finding that $K_m \sim \bar {\xi }^{-1} (Ra_{vib}^{eff})^{\gamma }$ with the fitting scaling exponent $\gamma = 0.150 \pm 0.025$. We subsequently quantify the characteristics of the interface roughness amplitude evolution in microgravity vibroconvection. Our results indicate that the roughness amplitude exhibits a power-law dependence on the mean height of the liquid layer. Drawing from the Stefan boundary condition, we theoretically deduce this dependence under the assumption of a non-uniform heat flux distribution at the interface, where the theory is corroborated by our numerical simulations.
A high-energy pulsed vacuum ultraviolet (VUV) solid-state laser at 177 nm with high peak power by the sixth harmonic of a neodymium-doped yttrium aluminum garnet (Nd:YAG) amplifier in a KBe2BO3F2 prism-coupled device was demonstrated. The ultraviolet (UV) pump laser is a 352 ps pulsed, spatial top-hat super-Gaussian beam at 355 nm. A high energy of a 7.12 mJ VUV laser at 177 nm is obtained with a pulse width of 255 ps, indicating a peak power of 28 MW, and the conversion efficiency is 9.42% from 355 to 177 nm. The measured results fitted well with the theoretical prediction. It is the highest pulse energy and highest peak power ever reported in the VUV range for any solid-state lasers. The high-energy, high-peak-power, and high-spatial-uniformity VUV laser is of great interest for ultra-fine machining and particle-size measurements using UV in-line Fraunhofer holography diagnostics.
Drug use Disorder (DUD), the risk for which is substantially influenced by both genetic and social factors, is geographically concentrated in high-risk regions. An important step toward understanding this pattern is to examine geographical distributions of the genetic liability to DUD and a key demographic risk factor – social deprivation.
Methods
We calculated the mean family genetic risk score (FGRS) for DUD ((FGRSDUD) and social deprivation for each of the 5983 areas Demographic Statistical Areas (DeSO) for all of Sweden and used geospatial techniques to analyze and map these factors.
Results
Using 2018 data, substantial spatial heterogeneity was seen in the distribution of the genetic risk for DUD in Sweden as a whole and in its three major urban centers which was confirmed by hot-spot analyses. Across DeSOs, FGRSDUD and s.d. levels were substantially but imperfectly correlated (r = + 0.63), with more scattering at higher FGRSDUD and s.d. scores. Joint mapping across DeSOs for FGRSDUD and s.d. revealed a diversity of patterns across Sweden. The stability of the distributions of FGRSDUD and s.d. in DeSOs within Sweden over the years 2012–2018 was quite high.
Conclusions
The geographical distribution of the genetic risk to DUD is quite variable in Sweden. DeSO levels of s.d. and FRGSDUD were substantially correlated but also disassociated in a number of regions. The observed patterns were largely consistent with known trends in the human geography of Sweden. This effort lays the groundwork for further studies of the sources of geographic variation in rates of DUD.
The large number of patients with ankle injuries and the high incidence make ankle rehabilitation an urgent health problem. However, there is a certain degree of difference between the motion of most ankle rehabilitation robots and the actual axis of the human ankle. To achieve more precise ankle joint rehabilitation training, this paper proposes a novel 3-PUU/R parallel ankle rehabilitation mechanism that integrates with the human ankle joint axis. Moreover, it provides comprehensive ankle joint motion necessary for effective rehabilitation. The mechanism has four degrees of freedom (DOFs), enabling plantarflexion/dorsiflexion, eversion/inversion, internal rotation/external rotation, and dorsal extension of the ankle joint. First, based on the DOFs of the human ankle joint and the variation pattern of the joint axes, a 3-PUU/R parallel ankle joint rehabilitation mechanism is designed. Based on the screw theory, the inverse kinematics inverse, complete Jacobian matrix, singular characteristics, and workspace analysis of the mechanism are conducted. Subsequently, the motion performance of the mechanism is analyzed based on the motion/force transmission indices and the constraint indices. Then, the performance of the mechanism is optimized according to human physiological characteristics, with the motion/force transmission ratio and workspace range as optimization objectives. Finally, a physical prototype of the proposed robot was developed, and experimental tests were performed to evaluate the above performance of the proposed robot. This study provides a good prospect for improving the comfort and safety of ankle joint rehabilitation from the perspective of human-machine axis matching.
This study investigates the flow structures and combustion regimes in an axisymmetric cavity-based scramjet combustor with a total temperature of 1800 K and a high Reynolds number of approximately 1 × 107. The hydroxyl planar laser-induced fluorescence technique, along with the broadband flame emission and CH* chemiluminescence, is employed to visualize the instantaneous flame structure in the optically accessible cavity. The jet-wake flame stabilization mode is observed, with intense heat release occurring in the jet wake upstream of the cavity. A hybrid Reynolds-averaged Navier–Stokes/large-eddy simulation approach is performed for the 0.18-equivalent-ratio case with a pressure-corrected flamelet/progress variable model. The combustion regime is identified mainly in the corrugated or wrinkled flamelet regime (approximately 102 < Da < 104, 103 < Ret < 105 where $Da$ is the Damköhler number and $Re_t$ is the turbulent Reynolds number). The combustion process is jointly dominated by supersonic combustion (which accounts for approximately 58 %) and subsonic combustion, although subsonic combustion has a higher heat release rate (peak value exceeding 1 × 109 J (m3s)−1). A partially premixed flame is observed, where the diffusion flame packages a considerable quantity of twisted premixed flame. The shockwave plays a critical role in generating vorticity by strengthening the volumetric expansion and baroclinic torque term, and it can facilitate the chemical reaction rates through the pressure and temperature surges, thereby enhancing the combustion. Combustion also shows a remarkable effect on the overall flow structures, and it drives alterations in the vorticity of the flow field. In turn, the turbulent flow facilitates the combustion and improves the flame stabilization by enhancing the reactant mixing and increasing the flame surface area.
Based on a new cored succession at Winterswijk, evidence is uncovered of the end-Triassic mass-extinction (ETME) event in a subsurface sedimentary succession of the Netherlands. The ETME was one of the most devastating events for the biosphere during the Phanerozoic era. Massive volcanism from the Central Atlantic Magmatic Province initiated the breakup of the supercontinent Pangea and resulted in terrestrial and marine extinction pulses, which drastically altered the course of life on Earth. The newly cored material reveals a sedimentary succession representing a shallow marine setting dominated by laminated black shale and claystone deposits. A high-resolution palynostratigraphic dataset provides evidence for a late Rhaetian vegetation assemblage that displays a stepwise decline of arborescent tree vegetation that is transiently replaced by a community of ferns and fern allies. Geochemical records link this major disturbance in palynofloral biodiversity to a pulse of volcanic activity as evidenced by a negative excursion in stable organic carbon isotopes. Shifts towards drier climate conditions, as inferred from sedimentary elemental composition, suggest continental aridification strongly influenced the terrestrial realm following volcanic pulses. Presence of reworked material suggests unstable soils that were affected by increased erosion rates, inhibiting the re-establishment of conifer tree vegetation. Comparison of our findings with other contemporaneous European Triassic-Jurassic boundary sections confirms the progression of the end-Triassic extinction, which exhibits a two-phased structure. The presence of the ETME in the subsurface of the Netherlands provides further evidence towards our understanding of terrestrial extinction with emphasis on the decline of vegetation.
In such a wide-ranging, long-standing, and international field of scholarship as Beowulf, one might imagine that everything would long since have been thoroughly investigated. And yet as far as the absolutely crucial question of the poem's origins is concerned, that is not the case. This cross-disciplinary study by Bo Gräslund argues that the material, geographical, historical, social, and ideological framework of Beowulf cannot be the independent literary product of an Old English Christian poet, but was in all essentials created orally in Scandinavia, which was a fertile seedbed for epic poetry.
This scoping review aimed to evaluate the effect of exercise combined with vitamin D supplementation on skeletal muscle health in older individuals. We implemented a systematic search of electronic databases, including PubMed, the Cochrane Library, Web of Science and Embase, which was conducted from the time of library construction to January 2024. Eligible studies were randomised controlled trials including men and women aged ≥ 65 years or mean age ≥ 65 years; exercise training and vitamin D supplementation; outcomes of muscular strength, function, muscular power, body composition and quality of life; and results compared with those of exercise intervention alone. The results showed thirteen studies including 1483 participants were identified. The proportions of male and female sex were 22·05 and 77·95 %, respectively. Exercise intervention methods included resistance exercises and multimodal exercise training. All vitamin D interventions involved supplementation with vitamin D3. A significant increase was identified in short physical performance battery and stair climbing but not in skeletal muscle mass, skeletal strength, the timed up and go test and gait speed in older adults after exercise combined with vitamin D supplementation. In conclusion, exercise combined with vitamin D supplementation has additive health effects on short physical performance battery and stair climbing. Furthermore, when vitamin D was deficient at baseline, the combined effect of exercise and vitamin D intervention significantly increased the timed up and go test and gait speed in older adults. In future randomised controlled trials on this topic, baseline vitamin D nutritional status, health condition and sex should be considered.
A high-energy picosecond 355 nm ultraviolet (UV) laser operating at 100 Hz was demonstrated. A 352 mJ, 69 ps, 1064 nm laser at 100 Hz was realized firstly by cascaded regenerative, laser diode end-pumped single-pass and side-pumped main amplifiers. The stimulated Raman scattering-based beam shaping technique, thermally induced birefringence compensation and 4f spatial filter-image relaying systems were used to maintain a relatively homogeneous beam intensity distribution during the amplification process. By using lithium triborate crystals for second- and third-harmonic generation (THG), a 172 mJ, approximately 56 ps, 355 nm UV laser was achieved with a THG conversion efficiency of 49%. To the best of our knowledge, it is the highest pulse energy of a picosecond 355 nm UV laser so far. The beam quality factor ${M}^2$ and pulse energy stability were ${M}_x^2$=3.92, ${M}_y^2$=3.71 and root mean square of 1.48%@3 hours. This laser system could play significant roles in applications including photoconductive switch excitation, laser drilling and laser micro-fabrication.
This article sets out to explain why Nigeria was unable to prevent the loss of heritage objects in the 1960s and 1970s. Obvious answers to this question would include the limited enforcement capacity of the African state and the complacency of European and North American art dealers. “How Our Heritage Is Looted” argues, however, that a colonial legal category, namely “antiquity,” played a key role in creating an ineffective enforcement regime for cultural property theft. The mismatch between the ordinary meaning of the term “antiquity,” denoting a remnant of an ancient civilization, and the kinds of modern crafts that the state wanted to protect ultimately resulted in the inability of Nigeria’s colonial preservation statute to convey clear rules to customs officers and museum curators about what exporters could take out of the country. Nigeria’s heritage law thus constituted a project of legal meaning-making whose failure facilitated illicit commerce.