Under global warming, many glaciers worldwide are receding. However, recent studies have suggested the extension of the Karakoram Anomaly, a region of anomalous glacier mass gain, into the western Kunlun and eastern Pamir mountains. However, the eastern limit of this anomaly in the Kunlun Mountains is unclear. This study, using changes in glacier area and surface elevation, estimates the eastern limit of the Kunlun-Pamir-Karakoram anomaly at ~85°E. Over the past 50 years, glaciers west of 85°E in the Kunlun Mountains decreased in area from 8401 to 7945 km2 at a rate of −0.12 ± 0.07% a−1, showed a reduction in the rate of retreat through time and have recently gained mass, with surface elevation changes of 0.15 ± 0.35 m a−1 over the period of 2000–2013. Glaciers east of 85°E have experienced greater rates of area change (−61 ± 12 km2 and −0.43 ± 0.13% a−1) over the past 50 years, accelerated area loss in recent years and elevation change rate of −0.51 ± 0.18 m a−1 between 2000 and 2013. These patterns of elevation and area change are consistent with regional increases in summer temperature in the eastern Kunlun Mountains and slight cooling in the western Kunlun Mountains.

Background: Singapore General Hospital (SGH) is the largest acute tertiary-care hospital in Singapore. Healthcare workers (HCWs) are at risk of acquiring COVID-19 in both the community and workplaces. SGH has a robust exposure management process including prompt contact tracing, immediate ring fencing, lock down of affected cubicles or single room isolation for patient contacts, and home isolation orders for staff contacts of COVID-19 cases during the containment phase of the pandemic. Contacts were also placed on enhanced surveillance with PCR testing on days 1 and 4 as well as daily antigen rapid tests (ARTs) for 10 days after exposure. Here, we describe the characteristic of HCWs with COVID-19 during the third wave of the COVID-19 pandemic. Methods: This retrospective observational study included all SGH HCWs who acquired COVID-19 during the third wave (ie, the 18-week period from September 1 to December 31, 2021) of the COVID-19 pandemic. Univariate analysis was used to compare characteristics of work-associated infection (WAI) and community-acquired infection (CAI) among HCWs. Results: Among a workforce of >10,000 at SGH, 335 HCWs acquired COVID-19 during study period. CAI (exposure to known clusters or household contact) accounted for 111 HCW infections (33.1%). Also, 48 HCWs (14.3%) had a WAI (ie, acquired at their work places where there was no patient contact). Among WAsI, only 5 HCWs had hospital-acquired infection (confirmed by phylogenetic analysis). The sources of exposure for the remaining 176 HCWs were unknown. Weekly incidence of COVID-19 among HCWs was comparable to the epidemiology curve of all cases in Singapore (Fig. 1 and 2). The mean age of HCWs with COVID-19 was 39.6 years, and most were women. At the time of positive SARS-CoV-2 PCR test, 223 HCWs were symptomatic, and 67 (20.0%) of them had comorbidities. Only 16 HCWs (4.8%) required hospitalization, and all recovered fully with no mortality (Table 1). Being female was associated with community COVID-19 acquisition (OR, 4.6, P Conclusions: During the thrid wave of the COVID-19 pandemic, a higher percentage of HCWs at SGH acquired the infection from the community than from the workplace. Safe management measures, such as universal masking, social distancing, and robust exposure management processes including prompt contact tracing and environmental disinfection, can reduce the risk of COVID-19 in the hospital work environment.

Funding: None

Disclosures: None

Background: Outpatient parenteral antimicrobial therapy (OPAT) is used in the outpatient setting to treat infectious conditions that require a prolonged course of antimicrobials. OPAT has been shown to decrease length of hospital stay and healthcare costs without compromising patient care and has become a widely accepted practice nationally. Due to this trend, the study of OPAT is of vital importance and will continue to be relevant moving forward. Currently, few studies have explored risk factors associated with OPAT complications, and most are limited in their analysis by indication. Further work should be performed to expand upon what is currently known. We characterized factors associated with increased OPAT complication risk. Methods: We conducted a retrospective cohort study at 4 sites across NYU Langone Health in patients admitted from 2017 to 2020. We applied the following inclusion criteria: aged ≥18 years and discharged with OPAT. Complications were defined as follows: vascular-access-related (line occlusion, thrombosis, dislodgement, central-line associated bloodstream infection or CLABSI) and antimicrobial-related (laboratory derangement, drug reaction, Clostridioides difficile infection), all-cause 30-day readmission, and OPAT-related readmission. Data were obtained from electronic medical records and the OPAT database. This study was granted a waiver from informed consent by the NYU Institutional Review Board. Multivariate logistic regression was performed, adjusting for confounding variables (sex, age, hospital of admission, history of chronic medical conditions, line type, and line duration). Results: Overall, 1,846 patient encounters of 5,951 reviewed met inclusion criteria. The median age was 66 (IQR, 26), 42.2% were female. Moreover, 810 (44%) received a peripherally inserted central catheter (PICC) and 1,036 (56%) received a midline cathether. Also, 563 (30.5%) were discharged to subacute rehabilitation (SAR). The most frequent complications were line dislodgement (4.2% of all patients), laboratory derangement (3.0%), and drug reaction (2.4%). Furthermore, 27 patients (1.5%) developed CLABSI. Patients discharged to SAR were more likely to develop CLABSI (OR, 4.1l; P = .005), and they had higher rates of OPAT-related 30-day readmissions (OR, 2.675; P = .004) compared to those who were discharged home, after adjusting for key confounders. Conclusions: Discharge to SAR is strongly associated with increased risk of readmission for OPAT-related complications and CLABSI, after adjusting for key confounders. CLABSI prevention during SAR admission is a critically needed public health intervention.

Funding: None

Disclosures: None

In neutrally stratified shallow water, full-depth Langmuir cells (LCs) can interact with the turbulent benthic boundary layer and, thus, influence bottom wall shear stresses. In this paper the impacts of full-depth LCs on the streamwise and spanwise wall shear stresses are systematically studied using the database obtained from wall-resolved large-eddy simulation of shallow-water Langmuir turbulence. Analyses focus on the instantaneous wall shear stress fluctuations and the joint probability density functions between the stress fluctuations and the LCs parts of the velocity fluctuations, which show that the linear superimposition effect and nonlinear modulation effect of LCs are responsible for the spanwise organized distribution of wall shear stress fluctuations. Compared with the statistics in pure shear-driven turbulence without LCs, the mean square values of wall shear stress fluctuations in shallow-water Langmuir turbulence are enhanced by the strong linear superimposition effect of LCs, while the skewness and kurtosis are reduced by the combination of the linear superimposition effect and nonlinear modulation effect of LCs. Based on the scalings of these effects, a new predictive model of wall shear stress fluctuations is proposed for shallow-water Langmuir turbulence. The proposed model can predict the spatial distribution and statistics of wall shear stress fluctuations using the LCs parts of velocity fluctuations measured above the water bottom. Owing to the persistence of the spanwise inhomogeneity of wall shear stresses induced by full-depth LCs, the new predictive model will be useful for improving the wall-layer modelling for shallow-water Langmuir turbulent flows.

Lower-crust-derived adakitic rocks in the Gangdese belt provide important constraints on the timing of Tibetan crustal thickening and on the relative contributions of magmatic and tectonic processes. Here we present geochronological and geochemical data for the Wangdui porphyritic monzogranites in the western Gangdese belt. Zircon U–Pb dating yields emplacement ages of 46–44 Ma. All samples have high Sr (321–599 ppm), low Yb (0.76–1.33 ppm) and Y (10.6–18.3 ppm) contents, with high La/Yb (51.1–72.3) and Sr/Y (21.0–51.4) ratios, indicating adakitic affinities. The low MgO (0.97–1.76 wt %), Cr (7.49–53.6 ppm) and Ni (4.75–29.1 ppm) contents, as well as high 87Sr/86Sr(i) (0.7143–0.7145), low ϵNd(t) (−10.4 to −9.8) and zircon ϵHf(t) (−17.7 to 0.4) values, suggest that the Wangdui pluton most likely originated from partial melting of the thickened ancient lower crust. In combination with previously published data, despite the east–west-trending heterogeneity of crustal composition in the Gangdese belt, the La/Yb ratios of magmatic rocks reveal that both western and eastern segments experienced remarkable crustal thickening in the Eocene. However, in contrast to the thickened juvenile lower crust in the eastern segment formed by the underplating of mantle-derived magmas, tectonic shortening plays a more crucial role in thickening of the ancient basement in western Gangdese. In fact, such Eocene-thickened ancient lower-crust-derived adakitic rocks are widely distributed in the central Himalayan–Tibetan orogen. This, together with the extensive development of fold–thrust belts, suggests that tectonic shortening might be the main mechanism accounting for the crustal thickening associated with the India–Asia collision.

Ammannia multiflora Roxb. is a dominant broadleaf weed that is a serious problem in southern China rice fields, and acetolactate synthase (ALS)-inhibiting herbicides have been used for its control for more than 20 years. Excessive reliance on ALS-inhibiting herbicides has led to herbicide resistance in A. multiflora. In this study, 10 A. multiflora populations from the Jiangsu Province of China were collected, and the resistance levels and target site–resistance mechanisms to ALS-inhibiting herbicides bensulfuron-methyl and penoxsulam were investigated. The dose–response assays showed that eight populations evolved resistance to bensulfuron-methyl (9.1- to 90.9-fold) and penoxsulam (5.0- to 103.1-fold). Amplification of ALS genes indicated that there were three ALS genes (AmALS1, AmALS2, and AmALS3) in A. multiflora. Sequence analysis revealed amino acid mutations at Pro-197 in either AmALS1 (Pro-197-Ala, Pro-197-Ser, and Pro-197-His) or AmALS2 (Pro-197-Ser and Pro-197-Arg) in resistant populations, and no mutations were found in AmALS3. Moreover, two independent mutations (Pro-197-Ala in AmALS1 and Pro-197-Ser in AmALS2 or Pro-197-Ala in AmALS1 and Pro-197-Arg in AmALS2) coexisted in two resistant populations, respectively. In addition, the auxin mimic herbicides MCPA and florpyrauxifen-benzyl, the photosystem II inhibitor bentazon, and the protoporphyrinogen oxidase inhibitor carfentrazone-ethyl can effectively control the resistant A. multiflora populations. Our study demonstrates the wide prevalence of ALS inhibitor–resistant A. multiflora populations in Jiangsu Province and the diversity of Pro-197 mutations in ALS genes and provides alternative herbicide options for controlling resistant A. multiflora populations.

Direct numerical simulations (DNS) are used to systematically investigate the applicability of the minimal-channel approach (Chung et al., J. Fluid Mech., vol. 773, 2015, pp. 418–431) for the characterization of roughness-induced drag on irregular rough surfaces. Roughness is generated mathematically using a random algorithm, in which the power spectrum (PS) and probability density function (p.d.f.) of the surface height can be prescribed. Twelve different combinations of PS and p.d.f. are examined, and both transitionally and fully rough regimes are investigated (roughness height varies in the range $k^+ = 25$–100). It is demonstrated that both the roughness function (${\rm \Delta} U^+$) and the zero-plane displacement can be predicted with ${\pm }5\,\%$ accuracy using DNS in properly sized minimal channels. Notably, when reducing the domain size, the predictions remain accurate as long as 90 % of the roughness height variance is retained. Additionally, examining the results obtained from different random realizations of roughness shows that a fixed combination of p.d.f. and PS leads to a nearly unique ${\rm \Delta} U^+$ for deterministically different surface topographies. In addition to the global flow properties, the distribution of time-averaged surface force exerted by the roughness onto the fluid is calculated. It is shown that patterns of surface force distribution over irregular roughness can be well captured when the sheltering effect is taken into account. This is made possible by applying the sheltering model of Yang et al. (J. Fluid Mech., vol. 789, 2016, pp. 127–165) to each specific roughness topography. Furthermore, an analysis of the coherence function between the roughness height and the surface force distributions reveals that the coherence drops at larger streamwise wavelengths, which can be an indication that very large horizontal scales contribute less to the skin-friction drag.

To set the sleeping mode for the Yutu-2 rover, a visual pose prediction algorithm including terrain reconstruction and pose estimation was first studied. The terrain reconstruction precision is affected by using only the stereo navigation camera (Navcam) images and the rotation angles of the mast. However, the hazard camera (Hazcam) pose is fixed, and an image network was constructed by linking all of the Navcam and Hazcam stereoimages. Then, the Navcam pose was refined based on a multiview block bundle adjustment. The experimental results show that the mean absolute errors of the check points in the proposed algorithm were 10.4 mm over the range of $\boldsymbol{L}$ from 2.0 to 6.1 m, and the proposed algorithm achieved good prediction results for the rover pose (the average differences of the values of the pitch angle and the roll angle were −0.19 degrees and 0.29 degrees, respectively). Under the support of the proposed algorithm, engineers have completed the remote setting of the sleeping mode for Yutu-2 successfully in the Chang’e-4 mission operations.