Eavesdropping on wastewater pollution: Detecting discharge events from river outfalls via fiber-optic distributed acoustic sensing.

Wastewater discharge from outfall pipes can significantly impact river water quality and aquatic ecosystems. Effective outfall monitoring is critical for controlling pollution and protecting public health. This study demonstrates a novel distributed acoustic sensing (DAS) approach for detecting wastewater discharge events from outfall pipes located along rivers. Controlled field experiments were conducted in an industrial park river to systematically evaluate DAS performance. DAS detects vibrational signals imparted to suspended fiber-optic cables by turbulent wastewater flows, predominantly within 10-30 Hz, enabling continuous monitoring along entire river lengths. Vibrational power analysis locates outfalls with meter-level accuracy, while time-frequency techniques discern discharge timing and characteristics. Cable type and outfall-fiber separation influence on detection capability was assessed. Thermoplastic-jacketed tight buffer cables optimized detection through enhanced vibrational coupling. Vibrational energy decreased exponentially with separation, highlighting benefits of proximal deployment for sensitivity. However, detection range scales with discharge flow rate. Frequency centroid proved a robust feature with potential for automated discharge identification. Overall, DAS enables high spatiotemporal resolution monitoring to pinpoint concealed outfalls minimally invasively. This positions DAS as a promising tool supporting improved water governance through early pollution warnings and rapid source localization via outfall vibrational signatures emanating across river networks.

Improvement of Sensitivity of Pooling Strategies for COVID-19.

Group testing (or pool testing), for example, Dorfman's method or grid method, has been validated for COVID-19 RT-PCR tests and implemented widely by most laboratories in many countries. These methods take advantages since they reduce resources, time, and overall costs required for a large number of samples. However, these methods could have more false negative cases and lower sensitivity. In order to maintain both accuracy and efficiency for different prevalence, we provide a novel pooling strategy based on the grid method with an extra pool set and an optimized rule inspired by the idea of error-correcting codes. The mathematical analysis shows that (i) the proposed method has the best sensitivity among all the methods we compared, if the false negative rate (FNR) of an individual test is in the range [1%, 20%] and the FNR of a pool test is closed to that of an individual test, and (ii) the proposed method is efficient when the prevalence is below 10%. Numerical simulations are also performed to confirm the theoretical derivations. In summary, the proposed method is shown to be felicitous under the above conditions in the epidemic.

Trends in Coronavirus Disease 2019 Hospitalization and Prognosis: Gender Effect.

We here aimed to investigate the impact of gender on the clinical characteristics and laboratory results of patients with coronavirus disease 2019 (COVID-19) and provide clues to the pathological mechanisms underlying COVID-19. A retrospective study was performed. Clinical characteristics, severity of lung infection, laboratory results, and prognoses of patients of different gender were analyzed. A total of 242 patients were finally included. The median age was 58 years (IQR: 40-68), including 54 (22.3%) hospital staffs. Ninety-four (38.8%) were male and 148 (61.1%) were female. The proportion of patients with diabetes was significantly higher in the male group than in the female group (P=0.034). Male patients had a significantly larger proportion of severe lung infection, higher leukocyte count, neutrophil count, neutrophil-to-lymphocyte ratio, C-reactive protein, and procalcitonin than female. Furthermore, male patients had worse liver, cardiac, and coagulation function than their female counterparts. Male patients with COVID-19 showed more severe inflammation reaction and coagulation dysfunction than female patients. In conclusion, gender is associated with host response to SARS-CoV-2 infection.