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Body posture determination methods have many applications, including product design, ergonomic workplace design, human body simulation, virtual reality, and animation industry. Initiated in robotics, inverse kinematic (IK) method has been widely applied to proactive human body posture estimation. The analytic inverse kinematic (AIK) method is a convenient and time-saving type of IK methods. It is also indicated that, based on AIK methods, a specific body posture can be determined by the optimization of an arbitrary objective function. The objective of this paper is to predict the postures of human arms during reaching tasks. In this research, a human body model is established in MATLAB, where the middle rotation axis analytic kinematic method is accomplished, based on this model. The joint displacement function and joint discomfort function are selected to be initially applied in this AIK method. Results show that neither the joint displacement function nor the joint discomfort function predicts postures that are close enough to natural upper limb postures of human being, during reaching tasks. Therefore, a bi-criterion objective function is proposed by integrating the joint displacement function and joint discomfort function. The accuracy of the arm postures, predicted by the proposed objective function, is the most satisfactory, while the optimal value of the coefficient, in the proposed objective function, is determined by golden section search.
This is the first report on the association between trauma exposure and depression from the Advancing Understanding of RecOvery afteR traumA(AURORA) multisite longitudinal study of adverse post-traumatic neuropsychiatric sequelae (APNS) among participants seeking emergency department (ED) treatment in the aftermath of a traumatic life experience.
We focus on participants presenting at EDs after a motor vehicle collision (MVC), which characterizes most AURORA participants, and examine associations of participant socio-demographics and MVC characteristics with 8-week depression as mediated through peritraumatic symptoms and 2-week depression.
Eight-week depression prevalence was relatively high (27.8%) and associated with several MVC characteristics (being passenger v. driver; injuries to other people). Peritraumatic distress was associated with 2-week but not 8-week depression. Most of these associations held when controlling for peritraumatic symptoms and, to a lesser degree, depressive symptoms at 2-weeks post-trauma.
These observations, coupled with substantial variation in the relative strength of the mediating pathways across predictors, raises the possibility of diverse and potentially complex underlying biological and psychological processes that remain to be elucidated in more in-depth analyses of the rich and evolving AURORA database to find new targets for intervention and new tools for risk-based stratification following trauma exposure.
We conduct the first broad-based international study on bank-level failures covering 92 countries over 2000–2014, investigating national cultural variables as failure determinants. We find individualism and masculinity are positively associated with bank failure, but they operate through different channels. Managers in individualist countries assume more portfolio risk, while governments in masculine countries allow banks to operate with less liquidity and less often bail out troubled institutions. Findings are robust to accounting for endogeneity, different techniques and measures, and additional controls. Results have implications for prudential policies, including regulation, supervision, and bailout strategies, that may partially mitigate some negative effects of culture.
Schizophrenia is a common major mental disorder and prenatal nutritional deficiency may increase its risk. We aimed to investigate long-term impact of prenatal exposure to malnutrition on risk of schizophrenia in adulthood using the Chinese famine of 1959–1961 as a natural experiment.
We obtained data from the Second National Sample Survey on Disability implemented in 31 provinces in 2006, and restricted our analysis to 387,093 individuals born from 1956 to 1965. Schizophrenia was ascertained by psychiatrists based on the International Statistical Classification of Diseases, Tenth Revision. Famine severity was defined as cohort size shrinkage index. The famine effect on adult schizophrenia was estimated by difference-in-difference models, established by examining the variations of famine exposure across birth cohorts.
Compared with the reference cohort of 1965, famine cohorts (1959–1962) had significantly higher odds (OR: 1.84; 95% CI: 1.13, 3.00; P = 0.014) of schizophrenia in the rural population. After adjusting for multiple covariates, this association remained significant (OR: 1.82; 95% CI: 1.11, 2.98; P = 0.018). We did not observe statistically significant differences in odds of schizophrenia among famine cohorts compared with the reference cohort in the urban population.
Prenatal malnutrition exposure has a detrimental impact on risk of schizophrenia in adulthood in the rural population. Further studies were needed to investigate corresponding mechanisms on this topic.
Maternal exposure to major stressors during pregnancy has been found to increase the risk of neurodevelopmental, cognitive and psychiatric disorders in the offspring. However, the association between prenatal exposure to earthquake and the risk of adult schizophrenia has yet to be examined.
To explore the potential long-term effects of prenatal exposure to maternal stress on the risk of schizophrenia in adulthood, using the Great Tangshan Earthquake in 1976 as a natural experiment.
We obtained data from the Second China National Sample Survey on Disability, and analysed 94 410 Chinese individuals born between 1975 and 1979. We obtained difference-in-differences estimates of the earthquake effects on schizophrenia by exploiting temporal variation in the timing of earthquake exposure across four birth cohorts born between 1975 and 1979, along with geographical variation in earthquake severity at the prefecture level. Schizophrenia was ascertained by psychiatrists using the ICD-10 classification. Earthquake severity was measured by seismic intensity.
Earthquake cohort who experienced prenatal exposure to felt earthquake had higher risk of schizophrenia (odds ratio, 3.38; 95% CI 1.43–8.00) compared with the unexposed reference cohort. After specifying the timing of exposure by the trimester of pregnancy, prenatal exposure to felt earthquake during the first trimester of pregnancy increased the risk of adulthood schizophrenia significantly (odds ratio, 7.45; 95% CI 2.83–19.59).
Prenatal (particularly early pregnancy) exposure to maternal stress after a major disaster substantially affects the mental health of Chinese adults.
Due to the lack of an effective and noninvasive screening tool, the early diagnosis of colorectal cancer (CRC) is currently difficult. For the early diagnosis of CRC, we have developed Fe3O4-Dye800-single chain fragment variable (ScFv)egfr/vegfr nanoprobes. ScFvegfr/vegfr (ScFv2) conjugated onto Fe3O4 nanoprobes efficiently recognized CRC tumors in vitro and in vivo. Near-infrared fluorescence imaging modalities such as Dye800 were utilized simultaneously with magnetic resonance to enhance detection efficiency. Fe3O4-Dye800-ScFv2 successfully detected tiny CRC tumors; the synergistic ScFv2 successfully enhanced CRC targeting. Thus, Fe3O4-Dye800-ScFv2 nanoprobes may represent a new molecular imaging strategy for the early detection of CRC.
We examine the mechanisms through which firm capabilities moderate the impact of institutional forces upon firms’ adoption of environmental management strategy (EMS). Viewing the limitations of the institutional perspective in explaining the heterogeneity in firms’ EMS, we suggest that an important source of variation is the idiosyncratic capabilities of the firm in acquiring and allocating resources. Based on the strategic response theme of institutional theory and the resource-based view, we argue that the influence of institutional forces on EMS is contingent on the presence of environmental orientation and innovation capability. Using data collected from China, we test these notions. Our empirical results suggest that both environmental orientation and innovation capability positively moderate the effect of institutional forces on firm's EMS. By demonstrating how institutional forces and firm capabilities interact with each other, we enhance our understanding of how firms succeed in developing EMS.
In this addendum we provide further information on our results and findings as well as explanations and suggestions in relation to the low R2. Table 1 provides additional information i.e., the standard error of all estimates, exact p values instead of asterisks as the significance level on the base of Table 3 in the published manuscript.
Managerial ties (MT) are important for business performance by providing firms access to valuable resources and protecting them from opportunism. Drawing on the resource-based view and the market orientation (MO) literature, we argue that (1) MT can help exporting firms to enhance export performance; and (2) MO will help strengthen the positive effect of MT as MO directs the value of MT for improvement of competitive strategy and customer experience with a market focus on generation, dissemination, and use of market intelligence concerning existing and potential customers and competitors. Using a sample of 230 Chinese exporting firms, we found that MT is linked to superior export performance, and the link is positively moderated by MO. Therefore, this study expands our understanding of how firms can not only improve their export performance through the development of MT, but also use MO to reinforce MT and export performance association.
The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart–Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron–specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart–Thornley detector.
A uniaxial perfectly matched layer (PML) method is proposed for solving the scattering problem with multiple cavities. By virtue of the integral representation of the scattering field, we decompose the problem into a system of single-cavity scattering problems which are coupled with Dirichlet-to-Neumann maps. A PML is introduced to truncate the exterior domain of each cavity such that the computational domain does not intersect those for other cavities. Based on the a posteriori error estimates, an adaptive finite element algorithm is proposed to solve the coupled system. The novelty of the proposed method is that its computational complexity is comparable to that for solving uncoupled single-cavity problems. Numerical experiments are presented to demonstrate the efficiency of the adaptive PML method.
Strong electromagnetic fields are radiated during the operation of the intense electron-beam accelerator (IEBA), and it is investigated in this paper. It is obtained that the triggered spark-gap switch and the main switch of the IEBA are the radiation resources. Here, the radiation of the triggered spark-gap switch is researched carefully. Firstly, circuit simulation is used to simulate the current going through the switch. The electric fields generated by the current and its frequency spectra are both calculated. The electric fields of the IEBA are measured by using a bi-cone antenna. When the primary capacitor of the IEBA is charged to 20 kV, the radiation field with amplitude of 753.4 V/m, dominant frequency of 20.8 MHz and high frequency 100 MHz is obtained. The experiment results show reasonable agreements with the analysis. It is believed that the gas-gap switch is a new method to achieve wide-band radiation.
The idea of breast computed tomography (breast CT) was conceived and explored not long after computed tomography (CT) was developed and commercialized. First attempts to image breasts with CT involved the use of a specially designed CT system (CT/M) [1–5] as well as a conventional body scanner [6,7]. The CT/M system suffered from poor image quality and long scanning times and did not prove to be practical. The use of a body scanner for breast imaging requires the entire chest to be exposed and included in image reconstruction. This causes two problems: first, the chest is unnecessarily exposed, increasing radiation dose to the patient; second, since the breasts are only a small part of the chest, only a small number of voxels can be used to represent the breasts, leading to poor resolution. These problems led to attempts to develop edicated CT units in which one of the breasts was scanned with dedicated scanning hardware, sparing the rest of the chest from radiation and allowing all available voxels to be used to represent the breast in the reconstructed images, leading to much improved resolution. This new imaging technique involved a different imaging geometry, often referred to as pendant geometry, with the patient positioned prone with one breast protruding downward through an opening and scanned by a specially designed scanner underneath the table. Because of technological limitations, this concept was not pursued until the early 2000s.
We have studied boron profiles by using the ion beam recoil implantation. A boron layer was first deposited onto Si, followed by irradiation with Si ions at various energies to knock the boron. Conventional belief is that the higher the implantation energy, the deeper the recoil profiles. While this is true for low-energy incident ions, we show here that the situation is reversed for incident Si ions of higher energy due to the fact that recoil probability at a given angle is a strong function of the energy of the primary projectile. Our experiments show that 500-keV high-energy recoil implantation produces a shallower B profile than lower-energy implantation such as 10 keV and 50 keV. The secondary-ion-massspectrometry (SIMS) analysis shows that the distribution of recoiled B atoms scattered by the energetic Si ions agrees with our calculation results. Sub-100 nm p+/n junctions have been realized with a 500-keV Si ion beam.
GeB− Cluster ions have been used to effectively produce 0.65-2keV boron for low energy ion implantation. We have generated the GeB− cluster ions using the SNICS ion source (source of negative ion by cesium sputtering). Shallow junctions have been made by the GeB− cluster ions implanting into Si substrates at 15keV, 1×1015/cm2 and 5keV, 5×1014/cm2. The junction depth as small as 37nm has been achieved by rapid thermal annealing of the 5 keV sample at 1000°C for 1 second. A two-step annealing was also performed to study the diffusion of B in the GeB− ion cluster implanted Si by annealing the 15 keV implanted sample at 550°C/300sec+1000°C/10sec. We found that the junction depth of the two-step annealed sample was only half of the one-step annealed sample. TEM (transmission electron microscopy) showed clear recrystallization of the amorphized layer with no observable residual defects. We briefly discussed the role of Ge in regards to reduction of the junction depth.
In hydroxylated poly(styrene-b-butadiene-b-styrene) (HO–SBS) micelle, ZnS/CdS composite nanocrystals were prepared by adding Cd2+ ions and Zn2+ ions to the system sequentially. The resulting composites were identified with elemental analysis, transmission electron microscopy, x-ray diffraction, surface photovoltage spectroscopy, and electric field induced surface photovoltage spectroscopy.
In Czochralski-grown (CZ) silicon single crystals, antimony (Sb) doping decreases the oxygen concentration by enhancing oxygen evaporation from the melt surface. In this study, Ar ambient pressures of around 100 Torr over the silicon melt were found to suppress evaporation of oxide species. To clarify the effect of the growth chamber ambient pressure on oxygen concentration, heavily Sb-doped CZ silicon crystals were grown under Ar pressures of 30, 60, and 100 Torr. Increasing Ar pressure increases the oxygen and Sb concentrations at the melt surface. The oxygen concentration under an Ar pressure of 100 Torr was 1.2 times higher that under 30 Torr when the solidified fractions are 0.5 or larger. The oxygen evaporation rate is controllable by gas phase transport of Sb2O at high Ar pressures.