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الثقة في النظرية : نجاح لنظام التنمية (البديل) الخاص بالصين
جاء هذا الكتاب تحت عنوان «الثقة في النظرية : نجاح لنظام التنمية \"البديل\" الخاص بالصين» وهو من تأليف (مايا غيو) وترجمة عبد الرحمن النجار. يبحث الكتاب في التطور الصيني السريع خلال الستة عقود الماضية، والدور الذي لعبه الحزب الشيوعي الصيني في تحويل الصين إلى دولة اشتراكية حديثة مزدهرة وقوية وديمقراطية ومتطورة ثقافيا ويستكشف ويستكشف فيما إذا كان صعود الصين يهدد نموذج التنمية الغربي وخاصة بعد أن أضحى صعود الصين حقيقة لا جدال فيها. يعتبر هذا الكتاب من أنجح الكتب التي نشرت عن الصين اليوم. فهو يقدم حججا مقنعة حول نهوض الصين. وتستند الآراء المعبر عنها في الكتاب ليس فقط إلى 60 عاما من تاريخ جمهورية الصين الشعبية وإنجازاتها الملحوظة في العقود الثلاثة الماضية، ولكن أيضا على تاريخها الحديث منذ عام 1840، وتاريخها الذي دام 2000 عام كدولة موحدة، وحضارتها ذات ال 5000 سنة. وتعكس المقابلات التي أجرتها المؤلفة \"مايا غيو\" مراقبتها الدقيقة للصين اليوم. إذ تضمنت أشخاصا من دوائر مختلفة، تشمل مجالات خبرتهم السياسة والاقتصاد والمجتمع والوضع الوطني وتاريخ دبلوماسية الحزب الشيوعي الصيني والاستراتيجية العسكرية وإدارة ممتلكات الدولة والرعاية الصحية والأعمال التجارية الخاصة. وتختلف موضوعات المقابلات على نطاق واسع؛ فمن النظم والنظرية والتطوير والإصلاح، إلى نوعية الحياة والاستراتيجية والدبلوماسية وجميع من كان فيها يؤيدون التعلم من الحضارات الإنسانية، ولكنهم يصرون في الوقت نفسه على ضرورة اتخاذ مسار يناسب الصين بدلا من استنساخ النموذج الغربي. يأتي هذا الكتاب من ضمن سلسلة تتألف من ثلاثة كتب وهي : الثقة في المسار : نموذج جديد لقوة صاعدة، الثقة في النظرية : فلسفة الصين لنظام دولي جديد، والثقة في النظام : نجاح نظام التنمية \"البديل\" في الصين. بما يوفر للقارئ مقاربة نظرية وواقعية لمسار الصين ونظريتها ونظامها، ويشرح أسباب ثقة الدولة الصينية في خياراتها.
Book
Screening Accuracy of SARC-F for Sarcopenia in the Elderly: A Diagnostic Meta-Analysis
Sarcopenia is an age-related disease, which is characterized by a decline in muscle mass and function. It is one of the most important health issues in the elderly and often leads to a high rate and variety of adverse outcomes.
To evaluate the screening accuracy of SARC-F for sarcopenia in the elderly.
We conducted a meta-analysis using articles available in 6 databases including PubMed (Medline), Web of Science, Embase, Cochrane Controlled Register of Trials (CENTRAL), China Knowledge Resource Integrated Database (CNKI), and Wanfang databases from inception to May 2020. Participants: Adults aged 60 years and older.
Sarcopenia was defined by EWGSOP2, EWGSOP, AWGS, FNIH and IWGS. Two authors independently extracted data based on predefined criteria. Where data were available we calculated pooled summary estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and their 95% confidence interval (CI) based on different criteria using the hierarchical logistic regression modeling including bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) modeling.
We included 20 studies, with the prevalence of sarcopenia ranging from 6.42% to 21.56%. The number of the literatures using EWGSOP, EWGSOP2, AWGS, IWGS and FNIH as diagnostic criteria was 13, 4, 13, 8, 7, respectively. Bivariate analysis yielded a pooled sensitivity of 32% (95%CI: 19%–47%), 77% (95%CI: 49%–92%), 27% (95%CI: 16%–42%), 39% (95%CI: 27%–52%), 35% (95%CI: 23%–49%) and a pooled specificity of 86% (95%CI:77%–92%), 63% (95%CI: 43%–79%), 91% (95%CI: 85%–95%), 86% (95%CI: 76%–92%), 89% (95%CI: 81%–93%), respectively. The area under the HSROC curve were 0.68 (95%CI: 0.64–0.72), 0.75 (95%CI: 0.71–0.78), 0.73 (95%CI: 0.69–0.77), 0.67 (95%CI: 0.62–0.71), 0.70 (95%CI: 0.65–0.73), respectively.
The screening accuracy of SARC-F was various based on different diagnostic criteria. There were some limitations for SARC-F, however, considering the higher practicability and specificity for screening sarcopenia in practice, SARC-F was still an effective screening tool for sarcopenia in the elderly. And the screening accuracy of SARC-F needs further exploration when EWGSOP2 is applied as diagnostic criteria and geriatric inpatients are the target participants.
Journal Article
Global, regional prevalence, and risk factors of osteoporosis according to the World Health Organization diagnostic criteria: a systematic review and meta-analysis
Abstract This systematic review and meta-analysis estimated the global, regional prevalence, and risk factors of osteoporosis. Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from 8.0% in Oceania to 26.9% in Africa). Osteoporosis is a common metabolic bone disorder in the elderly, usually resulting in bone pain and an increased risk of fragility fracture, but few summarized studies have guided global strategies for the disease. Therefore, we pooled the epidemiologic data to estimate the global, regional prevalence, and potential risk factors of osteoporosis. We conducted a comprehensive literature search through PubMed, EMBASE, Web of Science, and Scopus, to identify population-based studies that reported the prevalence of osteoporosis based on the World Health Organization (WHO) criteria. Meta-regression and subgroup analyses were used to explore the sources of heterogeneity. The study was registered in the PROSPERO database (CRD42021285555). Of the 57,933 citations evaluated, 108 individual studies containing 343,704 subjects were included. The global prevalence of osteoporosis and osteopenia was 19.7% (95%CI, 18.0%–21.4%) and 40.4% (95%CI, 36.9%–43.8%). Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from Oceania 8.0% to 26.9% in Africa). The prevalence was higher in developing countries (22.1%, 95%CI, 20.1%–24.1%) than in developed countries (14.5%, 95%CI, 11.5%–17.7%). Our study indicates a considerable prevalence of osteoporosis among the general population based on WHO criteria, and the prevalence varies substantially between countries and regions. Future studies with robust evidence are required to explore risk factors to provide effective preventive strategies for the disease.
Journal Article
Anomalous collapses of Nares Strait ice arches leads to enhanced export of Arctic sea ice
The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of Arctic Ocean multi-year sea ice. The Arctic Ocean is evolving towards an ice pack that is younger, thinner, and more mobile and the fate of its multi-year ice is becoming of increasing interest. Here, we use sea ice motion retrievals from Sentinel-1 imagery to report on the recent behavior of these ice arches and the associated ice fluxes. We show that the duration of arch formation has decreased over the past 20 years, while the ice area and volume fluxes along Nares Strait have both increased. These results suggest that a transition is underway towards a state where the formation of these arches will become atypical with a concomitant increase in the export of multi-year ice accelerating the transition towards a younger and thinner Arctic ice pack.
Ice arches that form along Nares Strait, which separates Greenland and Ellesmere Island, act to reduce the export of thick multi-year ice out of the Arctic. Here, we show that there has been a recent trend towards shorter duration arch formation that has resulted in enhanced transport of ice along the strait.
Journal Article
Diverse polarization angle swings from a repeating fast radio burst source
Fast radio bursts (FRBs) are millisecond-duration radio transients
1
,
2
of unknown origin. Two possible mechanisms that could generate extremely coherent emission from FRBs invoke neutron star magnetospheres
3
–
5
or relativistic shocks far from the central energy source
6
–
8
. Detailed polarization observations may help us to understand the emission mechanism. However, the available FRB polarization data have been perplexing, because they show a host of polarimetric properties, including either a constant polarization angle during each burst for some repeaters
9
,
10
or variable polarization angles in some other apparently one-off events
11
,
12
. Here we report observations of 15 bursts from FRB 180301 and find various polarization angle swings in seven of them. The diversity of the polarization angle features of these bursts is consistent with a magnetospheric origin of the radio emission, and disfavours the radiation models invoking relativistic shocks.
Polarization observations of the fast radio burst FRB 180301 with the FAST radio telescope show diverse polarization angle swings, consistent with a magnetospheric origin of the emission.
Journal Article
Additional flight delays and magnetospheric–ionospheric disturbances during solar storms
Although the sun is really far away from us, some solar activities could still influence the performance and reliability of space-borne and ground-based technological systems on Earth. Those time-varying conditions in space caused by the sun are also called solar storm or space weather. It is known that aviation activities can be affected during solar storms, but the exact effects of space weather on aviation are still unclear. Especially how the flight delays, the top topic concerned by most people, will be affected by space weather has never been thoroughly researched. By analyzing huge amount of flight data (~ 4 × 10
6
records), for the first time, we quantitatively investigate the flight delays during space weather events. It is found that compared to the quiet periods, the average arrival delay time and 30-min delay rate during space weather events are significantly increased by 81.34% and 21.45% respectively. The evident negative correlation between the yearly flight regularity rate and the yearly mean total sunspot number during 22 years also confirms such correlation. Further studies show that the flight delay time and delay rate will monotonically increase with the geomagnetic field fluctuations and ionospheric disturbances. These results indicate that the interferences in communication and navigation during space weather events may be the most probable reason accounting for the increased flight delays. The above analyses expand the traditional field of space weather research and could also provide us with brand new views for improving the flight delay predications.
Journal Article
Understanding colossal barocaloric effects in plastic crystals
Plastic crystal neopentylglycol (NPG) exhibits colossal barocaloric effects (BCEs) with record-high entropy changes, offering exciting prospects for the field of solid-state cooling through the application of moderate pressures. Here, we show that the intermolecular hydrogen bond plays a key role in the orientational order of NPG molecules, while its broken due to thermal perturbation prominently weakens the activation barrier of orientational disorder. The analysis of hydrogen bond strength, rotational entropy free energy and entropy changes provides insightful understanding of BCEs in order-disorder transition. External pressure reduce the hydsrogen bond length and enhance the activation barrier of orientational disorder, which serves as a route of varying intermolecular interaction to tune the order-disorder transition. Our work provides atomic-scale insights on the orientational order-disorder transition of NPG as the prototypical plastic crystal with BCEs, which is helpful to achieve superior caloric materials by molecular designing in the near future.
Colossal barocaloric effects with high entropy changes is reported in plastic crystal neopentylglycol, while microscopic mechanism needs to be further explored. Here, the authors show hydrogen bond related reorientational dynamics of neopentylglycol and provide insights in order-disorder transition.
Journal Article
A fast radio burst source at a complex magnetized site in a barred galaxy
Fast radio bursts (FRBs) are highly dispersed, millisecond-duration radio bursts
1
–
3
. Recent observations of a Galactic FRB
4
–
8
suggest that at least some FRBs originate from magnetars, but the origin of cosmological FRBs is still not settled. Here we report the detection of 1,863 bursts in 82 h over 54 days from the repeating source FRB 20201124A (ref.
9
). These observations show irregular short-time variation of the Faraday rotation measure (RM), which scrutinizes the density-weighted line-of-sight magnetic field strength, of individual bursts during the first 36 days, followed by a constant RM. We detected circular polarization in more than half of the burst sample, including one burst reaching a high fractional circular polarization of 75%. Oscillations in fractional linear and circular polarizations, as well as polarization angle as a function of wavelength, were detected. All of these features provide evidence for a complicated, dynamically evolving, magnetized immediate environment within about an astronomical unit (
au
; Earth–Sun distance) of the source. Our optical observations of its Milky-Way-sized, metal-rich host galaxy
10
–
12
show a barred spiral, with the FRB source residing in a low-stellar-density interarm region at an intermediate galactocentric distance. This environment is inconsistent with a young magnetar engine formed during an extreme explosion of a massive star that resulted in a long gamma-ray burst or superluminous supernova.
Analysis of a set of 1,863 bursts from the repeating source FRB 20201124A provides evidence of a complicated magnetized site within about an astronomical unit from the source in a barred galaxy.
Journal Article
Measurements of ozone and its precursors in Beijing during summertime: impact of urban plumes on ozone pollution in downwind rural areas
Sea-land and mount-valley circulations are the dominant mesoscale synoptic systems affecting the Beijing area during summertime. Under the influence of these two circulations, the prevailing wind is southwesterly from afternoon to midnight, and then changes to northeasterly till forenoon. In this study, surface ozone (O3), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxide (NOx) and non-methane hydrocarbons (NMHCs) were measured at four sites located along the route of prevailing wind, including two upwind urban sites (Fengtai \"FT\" and Baolian \"BL\"), an upwind suburban site (Shunyi \"SY\") and a downwind rural site (Shangdianzi \"SDZ\") during 20 June–16 September 2007. The purpose is to improve our understanding of ozone photochemistry in urban and rural areas of Beijing and the influence of urban plumes on ozone pollution in downwind rural areas. It is found that ozone pollution was synchronism in the urban and rural areas of Beijing, coinciding with the regional-scale synoptic processes. Due to the high traffic density and local emissions, the average levels of reactive gases NOx and NMHCs at the non-rural sites were much higher than those at SDZ. The level of long-lived gas CO at SDZ was comparable to, though slightly lower than, at the urban sites. We estimate the photochemical reactivity (LOH and the ozone formation potential (OFP) in the urban (BL) and rural (SDZ) areas using measured CO and NMHCs. The OH loss rate coefficient (LOH by total NMHCs at the BL and SDZ sites are estimated to be 50.7 s-1 and 15.8 s-1, respectively. While alkenes make a major contribution to the LOH, aromatics dominate OFP at both urban and rural sites. With respect to the individual species, CO has the largest ozone formation potential at the rural site, and at the urban site aromatic species are the leading contributors. While the O3 diurnal variations at the four sites are typical for polluted areas, the ozone peak values are found to lag behind one site after another along the route of prevailing wind from SW to NE. Intersection analyses of trace gases reveal that polluted air masses arriving at SDZ were more aged with both higher O3 and Ox concentrations than those at BL. The results indicate that urban plume can transport not only O3 but its precursors, the latter leading more photochemical O3 production when being mixed with background atmosphere in the downwind rural area.
Journal Article
Characteristics of flight delays during solar flares
Solar flares are one of the severest solar activities that have important effects on near-Earth space. Previous studies have shown that flight arrival delays increase as a result of solar flares, but the intrinsic mechanism behind this relationship is still unknown. In this study, we conducted a comprehensive analysis of flight departure delays during 57 solar X-ray events by using a huge amount of flight data (~ 5 × 10
6
records) gathered over a 5-year period. It is found that the average flight departure delay time during solar X-ray events increased by 20.68% (7.67 min) compared to quiet periods. Our analysis also revealed apparent time and latitude dependencies, with flight delays being more serious on the dayside than on the nightside and longer (shorter) delays tending to occur in lower (higher) latitude airports during solar X-ray events. Furthermore, our results suggest that the intensity of solar flares (soft X-ray flux) and the Solar Zenith Angle directly modulate flight departure delay time and delay rate. These results indicate that communication interferences caused by solar flares directly affect flight departure delays. This work expands our conventional understanding of the impacts of solar flares on human society and provides new insights for preventing or coping with flight delays.
Journal Article