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The aim of this study was to investigate risk factors and psychological stress of health-care workers (HCWs) with coronavirus disease 2019 (COVID-19) in a nonfrontline clinical department.
Data of 2 source patients and all HCWs with infection risk were obtained in a department in Wuhan from January to February 2020. A questionnaire was designed to evaluate psychological stress of COVID-19 on HCWs.
The overall infection rate was 4.8% in HCWs. Ten of 25 HCWs who contacted with 2 source patients were diagnosed with confirmed COVID-19 (8/10) and suspected COVID-19 (2/10). Other 2 HCWs were transmitted by other patients or colleagues. Close care behaviors included physical examination (6/12), life nursing (4/12), ward rounds (4/12), endoscopic examination (2/12). Contacts fluctuated from 1 to 24 times and each contact was short (8.1 min ± 5.6 min). HCWs wore surgical masks (11/12), gloves (7/12), and isolation clothing (3/12) when providing medical care. Most HCWs experienced a mild course with 2 asymptomatic infections, taking 9.8 d and 20.9 d to obtain viral shedding and clinical cure, respectively. Psychological stress included worry (58.3%), anxiety (83.3%), depression (58.3%), and insomnia (58.3%).
Close contact with COVID-19 patients and insufficient protection were key risk factors. Precaution measures and psychological support on COVID-19 is urgently required for HCWs.
To investigate whether an after-school nutrition education (ASNE) programme can improve the nutrition knowledge and healthy eating behaviour of adolescents from economically disadvantaged families.
One-group pretest and posttest design. Nutrition knowledge and dietary intake were collected using a questionnaire, and anthropometric measurements were measured before and after the intervention. Nine components of healthy eating behaviour were assessed with reference to the Dietary Guideline of Taiwan. Pretest and posttest differences were analysed using generalised estimating equations.
Three after-school programmes in central and southern Taiwan. The ASNE programme comprised three monthly 1-h sessions (20–30-min lecture and 30–40-min interaction).
A total of 153 adolescents aged 10–15 years from economically disadvantaged families (seventy-eight elementary students and seventy-five junior high school students).
Elementary and junior high school students’ nutrition knowledge scores (range 0–6) increased by 0·28 (+ 5·7 %, P = 0·02) and 0·30 points (+ 6·18 %, P = 0·02), respectively, but their fruit intake decreased by 0·36 serving/d (–22·9 %, P = 0·02) and 0·29 serving/d (–18·9 %, P = 0·03), respectively. Junior high school students’ mean snacking frequency and fried food intake dropped to 0·75 d/week (–21·3 %, P = 0·008) and 0·10 serving/d (–28·8 %, P = 0·01), respectively.
Short-term ASNE programmes can increase nutrition knowledge and reduce snacking frequency and fried food intake despite a decrease in fruit intake among adolescents from economically disadvantaged families.
Previous neuroimaging studies demonstrated that retinal detachment (RD) subjects were associated with abnormal spontaneous brain activities; however, whether the altered interhemispheric functional connectivity (FC) occurred in RD patients remains unknown. The current study tried to explore the alternations of interhemispheric FC of the whole brain in unilateral RD patients using the voxel-mirrored homotopic connectivity (VMHC) method and their connections to clinical features. Methods: We recruited 30 patients with RD (16 males and 14 females) and 30 healthy controls (HCs) (16 males and 14 females) whose age and sex were closely matched. All subjects underwent the rs-fMRI scans. The VMHC method was applied to directly assess the hemispheres’ functional interaction. The VMHC in these brain areas, which could be used as biomarkers to differentiate RD from HC, was identified by the receiver operating characteristic (ROC) curve analyses. The relations between these patients’ clinical features and their mean VMHC signal values in multiple brain regions were calculated by Pearson correlation analysis. Results: RD patients had significantly lower VMHC values than HCs in the bilateral occipital lobe (Brodmann areas, BA 18), bilateral superior temporal gyrus (BA 39), and bilateral cuneus (BA 19). Moreover, the mean VMHC signal values of the bilateral cuneus were in positive correlation with the duration of the RD (r = 0.446, P = 0.013). Conclusion: Our results provided an evidence of disturbed interhemispheric FC in the visual area occurred in RD patients, which might provide some useful information to understand the neural mechanism of RD patients with acute vision loss. Furthermore, the VMHC values might indicate the progress of the RD.
Italian ryegrass has invaded wheat ﬁelds in China and is becoming a predominant, troublesome weed. Fenoxaprop-P-ethyl has been widely used for weed control on Chinese farms since the 1990s. However, overuse has led to fenoxaprop-P-ethyl resistance in Italian ryegrass in Chinese wheat fields. In this study, we identified a putative fenoxaprop-P-ethyl–resistant population of Italian ryegrass, HZYC-6, from Henan province, China. Mutations involving Asp-2078-Gly and Ile-1781-Leu substitutions were identified in the carboxyl-transferase domain of acetyl-coenzyme A carboxylase in this population, and these mutations are the likely cause of the target site–based resistance to fenoxaprop-P-ethyl. In addition, we identified cytochrome P450–mediated metabolism of herbicides (non–target site based resistance) in the HZYC-6 population, indicating that multiple mechanisms of resistance may be segregating in this population. Furthermore, HZYC-6 was also highly resistant to haloxyfop-R-methyl and quizalofop-P-ethyl, moderately resistant to clodinafop-propargyl and sethoxydim, and had low resistance to clethodim and pinoxaden.
Previous studies have yielded conflicting results on the associations of maternal Fe intake with birth outcomes. This study aimed to investigate the associations between maternal Fe intake (total Fe from diet and supplements, dietary total Fe, haeme Fe, non-haeme Fe and Fe supplements use) and adverse birth outcomes in Shaanxi Province of Northwest China. In all, 7375 women were recruited using a stratified multistage random sampling method at 0–12 months (median 3; 10th–90th percentile 0–7) after delivery. Diets were collected by a validated FFQ and maternal characteristics were obtained via a standard questionnaire. The highest tertile of haeme Fe intake compared with the lowest tertile was negatively associated with low birth weight (LBW) (OR 0·68; 95 % CI 0·49, 0·94), small for gestational age (SGA) (OR 0·76; 95 % CI 0·62, 0·94) and birth defects (OR 0·55; 95 % CI 0·32, 0·89). Maternal haeme Fe intake was associated with a lower risk of intra-uterine growth retardation (IUGR) (medium tertile v. lowest tertile: OR 0·78; 95 % CI 0·61, 0·95; highest tertile v. lowest tertile: OR 0·76; 95 % CI 0·59, 0·93; Ptrend=0·045). The OR of LBW associated with Fe supplements use were as follows: during pregnancy: 0·72 (95 % CI 0·50, 0·95); in the second trimester: 0·67 (95 % CI 0·42, 0·98); in the third trimester: 0·47 (95 % CI 0·24, 0·93). We observed no associations of total Fe, dietary total Fe or non-haeme Fe intake with birth outcomes. The results suggest that maternal haeme Fe intake is associated with a reduced risk of LBW, SGA, IUGR and birth defects, and Fe supplements use during pregnancy reduces LBW risk.
This work proposes a query-by-singing (QBS) content-based music retrieval (CBMR) system that uses Approximate Karbunen–Loeve transform for noise reduction. The proposed QBS-CBMR system uses a music clip as a search key. First, a 51-dimensional matrix containing 39-Mel-frequency cepstral coefficients (MFCCs) features and 12-Chroma features are extracted from an input music clip. Next, adapted symbolic aggregate approximation (adapted SAX) is used to transform each dimension of features into a symbolic sequence. Each symbolic sequence corresponding to each dimension of MFCCs is then converted into a structure called advanced fast pattern index (AFPI) tree. The similarity between the query music clip and the songs in the database is evaluated by calculating a partial score for each AFPI tree. The final score is obtained by calculating the weighted sum of all partial scores, where the weighting of each partial score is determined by its entropy. Experimental results show that the proposed music retrieval system performs robustly and accurately with the entropy weighting mechanism.
In this paper, the recent studies of laboratory astrophysics with strong magnetic fields in China have been reviewed. On the Shenguang-II laser facility of the National Laboratory on High-Power Lasers and Physics, a laser-driven strong magnetic field up to 200 T has been achieved. The experiment was performed to model the interaction of solar wind with dayside magnetosphere. Also the low beta plasma magnetic reconnection (MR) has been studied. Theoretically, the model has been developed to deal with the atomic structures and processes in strong magnetic field. Also the study of shock wave generation in the magnetized counter-streaming plasmas is introduced.
In this work, we reported the optical photometry monitoring results for two brightest nearby quasars, PHL 1811 and 3C 273 using the ST-6 camera at Abastumani Observatory, Georgia. For PHL 1811, we found 3 microvariability events with time scale of ΔT = 6.0 min. For 3C273, we found that the largest variations are ΔV = 0.369 ± 0.028 mag, ΔR = 0.495 ± 0.076 mag, and ΔI = 0.355 ± 0.009 mag. When periodicity analysis methods are adopted to the available data, a period of p = 5.80 ± 1.12 years is obtained for PHL 1811, and p = 21.10 ± 0.14, 10.00 ± 0.14, 7.30 ± 0.09, 13.20 ± 0.09, 2.10 ± 0.06, and 0.68 ± 0.05 years are obtained for 3C 273.
Variability is one of the extreme observational properties of BL Lacertae objects. AO 0235+164 is a well studied BL Lac through the whole electro-magnetic wavebands, it is violently variable in the optical bands. In the present work, we show its optical R band photometric observations carried out during the period of Nov. 2006 to Dec. 2012 using the Ap6E CCD camera attached to the primary focus of the 70 cm meniscus telescope at Abastumani Observatory, Georgia. It shows a large variation of ΔR = 4.88 mag (14.20 - 19.08 mag) during our monitoring period. When periodicity analysis methods are adopted to its R observations from our Abastumani monitoring programme and those in the literature, the signs of some periods, P1 = 8.26 yr, P2 = 0.55 yr, P3 = 0.85 yr, P4 = 1.99 yr are found.
In this talk, we will show the beaming effect for Fermi/LAT blazars, then we discuss the correlations between γ-ray luminosity and other parameters, such as radio Doppler factors, superluminal motions, and core-dominance parameters. We also compare the Doppler factors determined from the γ-ray luminosity, X-ray emissions, and the short-term time scales with those from other methods. Our discussions suggest that γ-ray emissions may be strongly beamed.
Celestial navigation is an important type of autonomous navigation technology which could be used as an alternative to Global Navigation Satellite Systems (GNSS) when a vessel is at sea. After several centuries of development, a variety of astronomical vessel position (AVP) determination methods have been invented, but the basic concepts of these methods are all based on angular observations with a device such as a sextant, which has disadvantages including low accuracy, manual operation, and a limited period of observation. This paper proposes a new method that utilises a fisheye camera to image the celestial bodies and horizon simultaneously. Then, we calculate the obliquity of the fisheye camera's principal optical axis according to the image coordinates of the horizon. Next, we calculate the altitude of the celestial bodies according to the image coordinates of the celestial bodies and the obliquity. Finally, the AVP is determined by the altitudes according to the robust estimation method. Experimental results indicate that this method not only could realize automation and miniaturization of the AVP determination system, but could also greatly improve the efficiency of celestial navigation.
Site-testing measurements by the Australian group has already shown that Dome C on the Antarctic plateau is one of the best ground-based astronomical sites. Furthermore, Dome A, the Antarctic Kunlun Station, as the highest point on Antarctic inland plateau, where a Chinese Antarctic scientific expedition team first reached in 2005, is widely predicted to be an even better astronomical site by the international astronomical community. Preliminary site-testing carried out by the Center for Antarctic Astronomy (CAS) also confirms Dome A as a potential astronomical site. Multi-aperture scintillation sensors (MASS) can measure the seeing and isoplantic angle, the turbulence profile, etc., which are very important site-testing parameters that we urgently need. The MASS site testing at Dome A is presented here, and includes the method of processing data and the hardware for the extreme conditions of Dome A, Antarctica.
Sites on Antarctic plateau have unique atmospheric properties that make them better than any mid-latitude sites as observatory locations. From site testing measurements over 4 years on Dome A carried out by the Chinese Center for Antarctic Astronomy, we can reasonably predict that Dome A is as good as or even better than Dome C, which has been proved to be the best astronomical site by now, and suitable for high angular resolution observations. Seeing monitoring is necessary for planning large scale ground-based optical astronomical telescopes. In 2012, the 28th Chinese Antarctic Scientific Expedition carried out preliminary daytime seeing monitoring using a Differential Image Motion Monitor (DIMM) placed at a height of 3.5m. The median seeing was found to be 0.8″. This will be the foundation of future research that obtains comprehensive and long-period monitoring of the site's optical parameters.
An ecofriendly process has been successfully developed to synthesize the polycrystalline silver nanopolyhedrons with a high yield at large scale. By using tannic acid in the presence of poly (vinyl pyrrolidone) (PVP), high quality silver nanopolyhedrons were obtained in an aqueous one-pot reaction without any templates or auxiliaries. The film made from the silver nanostructures exhibits an electrical conductivity higher than 104 S/cm on both rigid and flexible substrates. The supreme mechanical strength of this silver film recommends its wide application in printing and flexible electronics.
Recent years have seen the great success of OFDM (orthogonal frequency division multiplexing) and DMT (discrete multitone) transceivers in many applications. The OFDM system has found many applications in wireless communications. It has been adopted in IEEE 802.11 for wireless local area networks, DAB for digital audio broadcasting, and DVB for digital video broadcasting. The DMT system is the enabling technology for high-speed transmission over digital subscriber lines. It is used in ADSL (asymmetric digital subscriber lines) and VDSL (very-high-speed digital subscriber lines). The OFDM and DMT systems are both examples of DFT transceivers that employ redundant guard intervals for equalization. Having a guard interval can greatly simplify the task of equalization at the receiver and it is now one of the most effective approaches for channel equalization. In this book we will study the OFDM and DMT under the framework of filter bank transceivers. Under such a framework, there are numerous possible extensions. The freedom in the filter bank transceivers can be exploited to better the systems for various design criteria. For example, transceivers can be optimized for minimum bit error rate, for minimum transmission power, or for higher spectral efficiency. We will explore all these possible optimization problems in this book.
The first three chapters describe the major building blocks relevant for the discussion of signal processing for communication and give the tools useful for solving problems in this area. Chapters 4–5 introduce the multirate building blocks and filter bank transceivers, and the basic idea of guard intervals for channel equalization. Chapter 6 gives a detailed discussion of OFDM and DMT systems. Chapters 7–10 consider the design of filter bank transceivers for different criteria and channel environments. A detailed outline is given at the end of Chapter 1. This book has been used as a textbook for a first-year graduate course at National Chiao Tung University, Taiwan, and at National Taiwan University. Most of the chapters can be covered in 16-18 weeks. Homework problems are given for Chapters 2–10.
In earlier chapters we saw that the use of redundancy in block transceivers allows us to remove ISI completely without using IIR filters. When the number of redundant samples per block v is more than the channel order L, there is no IBI, and we can further achieve zero ISI using a constant receiving matrix. The most notable example is the OFDM system studied in Chapter 6. But the use of redundant samples also decreases the transmission rate. For every M input symbols, the transmitter sends out N = M + ν samples. The actual transmission rate is decreased by a factor of N/M. There are ν redundant samples in every N samples transmitted. Reducing redundancy leads to a higher transmission rate and hence better bandwidth efficiency. At the same time, we would like the redundancy to be large enough so that the zero-forcing condition can still be satisfied without using IIR filters. A natural question to ask is: for a given channel and N, what is the smallest redundancy such that FIR transceivers exist? In other words, if we are to use an FIR transceiver that achieves zero ISI, what is the largest number of symbols that can be transmitted out of every N samples? This chapter aims to answer the question of minimum redundancy for the existence of FIR zero-forcing transceivers.
We will consider general FIR transceivers (Fig. 10.1) in which the filters are not constrained to be DFT filters as in the OFDM system. Moreover the length of the filters can be longer than the block size N. In this case the transmitting and receiving matrices are allowed to have memories, rather than constant matrices as in the OFDM case. We will see that the minimum redundancy depends on the underlying channel C(z), and it can be easily determined from the location of the zeros of the channel C(z) directly by inspection. The topic of minimum redundancy for FIR transceivers was first addressed in .