•A new tectonic division of the Xing’an–Mongolia orogenic belt (XMOB) in north China has been presented.•Four blocks and four sutures have been recognized in the XMOB.•The XMOB belongs to a ...pre-middle Devonian multiple orogenic belt in the Central Asian Orogenic Belt (CAOB).
A new tectonic division of the Xing’an–Mongolia orogenic belt (XMOB) in north China has been presented according to our research and a lot of new data of tectonics, geochronology and geochemistry. Four blocks and four sutures have been recognized in the XMOB, including the Erguna (EB), Xing’an–Airgin Sum (XAB), Songliao–Hunshandake (SHB), and Jiamusi (JB), and Xinlin–Xiguitu (XXS), Xilinhot–Heihe (XHS), Mudanjiang (MS) and Ondor Sum–Yongji sutures (OYS). The framework of the XMOB is characterized by a tectonic collage of the blocks and orogenic belts between them. Different Precambrian basements have been found in the blocks, including the Neoproterozoic metamorphic rocks and plutons in the EB, the Neoproterozoic metamorphic rocks in western and eastern of segments of the XAB, Mesoproterozoic and Neoproterozoic metamorphic rocks in middle segments of the XAB, respectively, the Neoproterozoic metamorphic rocks and Mesoproterozoic volcanic rocks and plutons in the SHB, and Neoproterozoic metamorphic rocks in the JB. The XXS resulted from a northwestward subduction of the XAB beneath the EB during the Cambrian, which was followed by the forming of the XHS and OYS in the northwest and south margins of the SHB in the Silurian, respectively. The MS was caused by a westward subduction of the JB beneath the east margin of the SHB during the middle Devonian. The three Cambrian, Silurian and middle Devonian events indicate that the XMOB belongs to a pre-middle Devonian multiple orogenic belt in the Central Asian Orogenic Belt (CAOB). Forming of the XMOB suggests that the southeast part of the Paleo Asian Ocean closed before the middle Devonian.
ABSTRACT
The urban heat island (UHI) phenomenon has been studied extensively, but there are relatively fewer reports on the so‐called urban cool island (UCI) phenomenon. We reveal here that the UCI ...phenomenon exists in Hong Kong during the day and is associated with the UHI at night under all wind and cloud conditions. The possible mechanisms for the UCI phenomenon in such a high‐rise compact city have been discovered using a lumped urban air temperature model. A new concept of urban cool island degree hours (UCIdh) to measure the UCI intensity and duration is proposed. Our analyses reveal that when anthropogenic heat is small or absent, a high‐rise, and high‐density city experiences a significant daytime UCI effect. This is explained by an intensified heat storage capacity and the reduced solar radiation gain of urban surfaces. However, if anthropogenic heat in the urban area increases further, the UCI phenomenon still exists; yet, UCIdh decrease dramatically in a high‐rise compact city. In a low‐rise, low‐density city, the UCI phenomenon also occurs when there is no anthropogenic heat, but easily disappears when there is little anthropogenic heat, and the UHI phenomenon dominates. This probably explains why the UHI phenomenon is often observed, but the UCI phenomenon is rarely observed. The co‐existence of urban heat/cool island phenomena implies reduction of the daily temperature range in such cities, and its dependence on urban morphology also implies that urban morphology can be used to control the urban thermal environment.
Virus-laden droplets dispersion may induce transmissions of respiratory infectious diseases. Existing research mainly focuses on indoor droplet dispersion, but the mechanism of its dispersion and ...exposure in outdoor environment is unclear. By conducting CFD simulations, this paper investigates the evaporation and transport of solid-liquid droplets in an open outdoor environment. Droplet initial sizes (dp = 10 μm, 50 μm, 100 μm), background relative humidity (RH = 35%, 95%), background wind speed (Uref = 3 m/s, 0.2 m/s) and social distances between two people (D = 0.5 m, 1 m, 1.5 m, 3 m, 5 m) are investigated.
Results show that thermal body plume is destroyed when the background wind speed is 3 m/s (Froude number Fr ~ 10). The inhalation fraction (IF) of susceptible person decreases exponentially when the social distance (D) increases from 0.5 m to 5 m. The exponential decay rate of inhalation fraction (b) ranges between 0.93 and 1.06 (IF=IF0e-b(D-0.5)) determined by the droplet initial diameter and relative humidity. Under weak background wind (Uref = 0.2 m/s, Fr ~ 0.01), the upward thermal body plume significantly influences droplet dispersion, which is similar with that in indoor space. Droplets in the initial sizes of 10 μm and 50 μm disperse upwards while most of 100 μm droplets fall down to the ground due to larger gravity force. Interestingly, the deposition fraction on susceptible person is ten times higher at Uref = 3 m/s than that at Uref = 0.2 m/s. Thus, a high outdoor wind speed does not necessarily lead to a smaller exposure risk if the susceptible person locating at the downwind region of the infected person, and people in outdoors are suggested to not only keep distance of greater than 1.5 m from each other but also stand with considerable angles from the prevailing wind direction.
Display omitted
•Droplet evaporation and transport in open outdoor space are studied by CFD.•Impacts of relative humidity (RH = 35%,95%) and droplet size (10–100 μm) are tested.•Thermal body plume is destroyed as Uref = 3 m/s while significant as Uref = 0.2 m/s.•Social distances (D = 0.5-5 m) for two face-to-face patients downwind are studied.•Exposure risk exponentially reduces with D at Uref = 3 m/s but exceeds that at 0.2 m/s.
Background:
Latissimus dorsi transfer (LDT) and pectoralis major transfer (PMT) were developed to treat an irreparable subscapularis tendon tear (ISScT); however, the difference in their outcomes ...remains unclear.
Purpose:
To systematically review and compare the outcomes of LDT and PMT for ISScT.
Study Design:
Systematic review; Level of evidence, 4.
Methods:
A systematic review was performed through a comprehensive search of Embase, PubMed, and the Cochrane Library. Studies of LDT or PMT were included according to the inclusion and exclusion criteria. The primary outcome was the Constant-Murley score (CMS) at the final follow-up. Secondary outcomes included the subjective shoulder value (SSV), visual analog scale (VAS) score for pain, active shoulder range of motion, and the belly-press and lift-off tests. Postoperative failure and complication rates were the safety outcome measures. Outcomes were summarized into the LDT and PMT groups, and results were compared statistically (P < .05).
Results:
Twelve studies were included in this review: 184 shoulders from 9 studies for the PMT group and 85 shoulders from 3 studies for the LDT group. For the PMT and LDT groups, the mean ages were 58.9 and 55.1 years, respectively, and the mean follow-up was 66.9 and 17.4 months, respectively. Overall, the LDT and PMT groups improved in the primary outcome (CMS) and secondary outcomes (SSV, VAS, ROM, and belly-press and lift-off tests), with low rates of failure and complication. When compared with the PMT group, the LDT group showed more significant improvements in CMS (35.2 vs 24.7; P < .001), active forward flexion (44.3° vs 14.7°; P < .001), abduction (35.0° vs 17.6°; P < .002), and positive belly-press test rate (45% vs 27%; P < .001). No statistically significant difference was seen between the groups in postoperative failure rate, complication rate, mean improvement of active internal rotation, VAS, or SSV.
Conclusion:
In general, LDT showed significantly better clinical outcomes postoperatively than did PMT. The available fair-quality evidence suggested that LDT might be a better choice for ISScT. Further evaluations on the relative benefits of the 2 surgical approaches are required, with more high-quality randomized controlled studies.
Background:
Complete arthroscopic repair can treat small to large rotator cuff tears (RCTs) with good outcomes; however, the repair might be compromised by inflammation.
Purpose:
To investigate the ...prognostic value of preoperative lymphocyte to monocyte ratio (LMR), a marker of systemic inflammation before surgery, in arthroscopic rotator cuff repair.
Study Design:
Case-control study; Level of evidence, 3.
Methods:
Between January 2014 and January 2016, primary small to large RCTs without stiffness, significant muscle fatty infiltration, or atrophy were completely repaired in 110 consecutive patients and followed. Preoperative LMR was obtained from blood routinely examined 1 day before surgery. Descriptive data and pre- and intraoperative variables were collected. Correlation analysis and multivariable linear regression analysis were used to determine the relationship between preoperative LMR and recovery including American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, Fudan University Shoulder Score (FUSS), visual analog scale (VAS) score for pain, and range of motion (ROM). Poor recovery was defined as ASES score <80, shoulder stiffness as external rotation ≤20°, and pain as VAS score >3. The predictive value of preoperative LMR was determined by receiver operating characteristic (ROC) curve.
Results:
A total of 99 patients (101 shoulders) were followed for 2.88 ± 0.43 years. Overall, mean ASES, Constant-Murley, FUSS, and VAS scores were significantly improved at the final follow-up; however, 27 cases had either ASES <80, shoulder stiffness, pain, or a combination of these. Correlation analysis and multivariable linear analysis showed that preoperative LMR was the only factor independently associated with functional recovery, pain, and ROM. Patients with poor recovery had lower preoperative LMR than those with good recovery. Based on the ROC curve, the cutoff value of preoperative LMR was 4.760. Patients with preoperative LMR <4.760 had significantly inferior clinical outcomes compared with their counterparts. The corresponding specificity was 0.542, and sensitivity was 0.779.
Conclusion:
Arthroscopic repair for small to large RCTs yielded good outcomes; however, some patients still had inferior functional scores, shoulder stiffness, or pain, which correlated with the level of preoperative systemic inflammation. As a marker of systemic inflammation, preoperative LMR could be prognostic for rotator cuff repair.
•We report the zircon ages and geochemical features of Erenhot ophiolitic complex.•It is the western continuation of Hegenshan ophiolite.•An incipient ocean basin probably had already developed ...during early Carboniferous.•It is related to lithospheric extension after subduction-slab breakoff.
The Eastern Erenhot ophiolitic complex (EOC) is one of the numerous fragments of oceanic lithosphere in southeastern Central Asian Orogenic Belt. It is composed dominantly of serpentinized ultramafic rocks with subordinate gabbros, mafic lavas and minor plagiogranite dikes. Zircons from two gabbros and one plagiogranite yielded weighted mean 206Pb/238U ages of 354.2±4.5Ma, 353.3±3.7Ma and 344.8±5.5Ma. These ages suggest that the oceanic crust of the EOC formed in a maximum time period of 10Ma, and that the plagiogranite may have formed later than the gabbroic section. An undeformed and unmetamorphosed dioritic porphyry dike intruded in the Carboniferous strata near the EOC has an intrusive age of 313.6±2.9Ma and provides a possible younger minimum time limit for the formation of the early Carboniferous ophiolitic complex. All the mafic rocks have similar chondrite normalized REE patterns characterized by moderate depletion in LREE with (La/Yb)N (0.20–0.75) similar to normal middle oceanic ridge basalt (N-MORB). The PM-normalized trace element patterns of the gabbros and massive basalts are also reasonably consistent, essentially similar to those of N-MORB except for some enrichment in LILE (e.g. Rb, Ba) and slightly negative Ti anomalies. The plagiogranite samples are characterized by lower K2O (0.45–0.73wt%) comparable with oceanic plagiogranite. They have LREE-enriched, chondrite-normalized REE patterns with varying Eu anomalies and the trace elements (e.g. Rb, Y, Nb) show similarity to volcanic arc granite. These geochemical features of the EOC show a similar volcanic arc affinity, suggesting that they form in a back-arc-type environment. Their origin is attributed to asthenospheric upwelling and further lithospheric extension during early Carboniferous, formed as a consequence of slab breakoff on collision of the northern early to mid-Paleozoic orogenic terrane and the Hunshandake Block.
Display omitted
•An infection-risk-based model is developed to quantify physical distancing safety threshold.•The 2-m physical distancing rule may increase transmission risk in stratified ...environment.•Infection risk is highly sensitive to stratification, exposure time and relative postures.
Physical distancing has been an important policy to mitigate the spread of the novel coronavirus disease 2019 (COVID-19) in public settings. However, the current 1–2 m physical distancing rule is based on the physics of droplet transport and could not directly translate into infection risk. We therefore revisit the 2-m physical distancing rule by developing an infection-risk-based model for human speaking. The key modeling framework components include viral load, droplets dispersion and evaporation, deposition efficiency, viral dose-response rate and infection risk. The results suggest that the one-size-fits-all 2-m physical distancing rule derived from the pure droplet-physics-based model is not applicable under some realistic indoor settings, and may rather increase transmission probability of diseases. Especially, in thermally stratified environments, the infection risk could exhibit multiple peaks for a long distance beyond 2 m. With Sobol’s sensitivity analysis, most variance of the risk is found to be significantly attributable to the variability in temperature gradient, exposure time and breathing height difference. Our study suggests there is no such magic 2 m physical distancing rule for all environments, but it needs to be used alongside other strategies, such as using face cover, reducing exposure time, and controlling the thermal stratification of indoor environment.
This paper investigates urban canopy layers (UCLs) ventilation under neutral atmospheric condition with the same building area density (λp = 0.25) and frontal area density (λf = 0.25) but various ...urban sizes, building height variations, overall urban forms and wind directions. Turbulent airflows are first predicted by CFD simulations with standard k-ε model evaluated by wind tunnel data. Then air change rates per hour (ACH) and canopy purging flow rate (PFR) are numerically analyzed to quantify the rate of air exchange and the net ventilation capacity induced by mean flows and turbulence. With a parallel approaching wind (θ = 0°), the velocity ratio first decreases in the adjustment region, followed by the fully-developed region where the flow reaches a balance. Although the flow quantities macroscopically keep constant, however ACH decreases and overall UCL ventilation becomes worse if urban size rises from 390 m to 5 km. Theoretically if urban size is infinite, ACH may reach a minimum value depending on local roof ventilation, and it rises from 1.7 to 7.5 if the standard deviation of building height variations increases (0%–83.3%). Overall UCL ventilation capacity (PFR) with a square overall urban form (Lx = Ly = 390 m) is better as θ = 0° than oblique winds (θ = 15°, 30°, 45°), and it exceeds that of a staggered urban form under all wind directions (θ = 0°–45°), but is less than that of a rectangular urban form (Lx = 570 m, Ly = 270 m) under most wind directions (θ = 30°–90°). Further investigations are still required to quantify the net ventilation efficiency induced by mean flows and turbulence.
•Urban canopy layer (UCL) ventilation (building packing density = 0.25) is quantified.•Purging flow rates (PFRs) and air change rate (ACH) are used to assess UCL ventilation.•If urban size rises, ACH decreases even if macroscopic flow quantities are constant.•Building height variations enhance ventilation across street roofs.•Overall urban form, staggered or aligned arrangement, wind directions are key factors.
There exist various vertical temperature gradients in different-type buildings. A holistic understanding of the impact of different temperature-stratified indoor environments on infection risk is ...necessary. In this work, the airborne transmission risk of SARS-CoV-2 in different thermally stratified indoor environments is assessed using our previously developed airborne infection risk model. Results show that the vertical temperature gradients in office building, hospital, classroom, etc. are within the range of −0.34 to 3.26 °C/m. In large space such as coach station, airport terminal, and sport hall, the average temperature gradient ranges within 0.13–2.38 °C/m in occupied zone (0–3 m); in ice rink with special requirements of indoor environment, the temperature gradient is higher than those in the above indoor spaces. The existence of temperature gradients causes multi-peaks of the transmission risk of SARS-CoV-2 with distancing, and our results show that in office, hospital ward and classroom, the second peak of the transmission risk is higher than 10
−3
in most contact scenarios, while most being lower than 10
−6
in large spaces like coach station and airport. The work is expected to provide some guidance on specific intervention policies in relation to the types of indoor environments.
Background:
Three-dimensional computed tomography (3D-CT) is commonly used for the evaluation of cam deformity; however, it does not display the cam border directly.
Purpose:
To compare the efficacy ...of the best-fit sphere (BFS) method and the alpha angle marking (AAM) method in 3D-CT evaluation for the cam border.
Study Design:
Cohort study (Diagnosis); Level of evidence, 3.
Methods:
Twenty-six cases of cam deformity, confirmed during hip arthroscopy, were included in this study. All patients underwent a CT scan before surgery. Using multiplanar reconstruction, we obtained reformatted CT images of oblique axial, oblique coronal, and radial views. The alpha angle and femoral head-neck offset ratio (hnoR) were measured on the reformatted CT images. The cam area on 3D-CT was displayed in 4 different ways: by importing the markers from the reformatted CT images of the oblique axial view (cam-oa), the oblique coronal view (cam-oc), or the radial view (cam-r) using the AAM method, or by using the BFS method (cam-bfs). The sizes and locations of the displayed cams were compared.
Results:
All hips in this study had an alpha angle greater than 60° and an hnoR smaller than 0.17. The radial view measured a larger alpha angle and smaller hnoR than the oblique axial and coronal views (P < .05). The areas of cam-oa, cam-oc, cam-r, and cam-bfs were 161.47 ± 27.96, 89.78 ± 19.23, 241.73 ± 34.55, and 329.75 ± 42.73 mm2, respectively, and their medial-to-lateral ranges along the acetabulum (clockface referents) were 12:30 to 03:00, 11:30 to 01:30, 11:30 to 03:00, and 11:00 to 03:30, respectively. Among the 4 displays, cam-bfs had the largest area and medial-to-lateral range (P < .05), and cam-r had the second largest area and range (P < .05). No significant difference in the mean distances from the acetabular rim to the superior border was detected among the 4 displays (P > .05).
Conclusion:
The cam area displayed by the BFS method on 3D-CT was larger than those evaluated by the AAM method. In the reformatted CT, the sizes and locations of cam deformity differed among the oblique axial, oblique coronal, and radial views, with the radial view showing the greatest area.
PDF
