Modelling study of transport time scales for a hyper-tidal estuary

This paper presents a study of two transport timescales (TTS), i.e., the residence time and exposure time, of a hyper-tidal estuary using a widely used numerical model. The numerical model was calibrated against field measured data for various tidal conditions. The model simulated current speeds and directions generally agreed well with the field data. The model was then further developed and applied to study the two transport timescales, namely the exposure time and residence time for the hyper-tidal Severn Estuary. The numerical model predictions showed that the inflow from the River Severn under high flow conditions reduced the residence and exposure times by 1.5 to 3.5% for different tidal ranges and tracer release times. For spring tide conditions, releasing a tracer at high water reduced the residence time and exposure time by 49.0% and 11.9%, respectively, compared to releasing the tracer at low water. For neap tide conditions, releasing at high water reduced the residence time and exposure time by 31.6% and 8.0%, respectively, compared to releasing the tracer at low water level. The return coefficient was found to be vary between 0.75 and 0.88 for the different tidal conditions, which indicates that the returning water effects for different tidal ranges and release times are all relatively high. For all flow and tide conditions, the exposure times were significantly greater than the residence times, which demonstrated that there was a high possibility for water and/or pollutants to re-enter the Severn Estuary after leaving it on an ebb tide. The fractions of water and/or pollutants re-entering the estuary for spring and neap tide conditions were found to be very high, giving 0.75–0.81 for neap tides, and 0.79–0.88 for spring tides. For both the spring and neap tides, the residence and exposure times were lower for high water level release. Spring tide conditions gave significantly lower residence and exposure times. The spatial distribution of exposure and residence times showed that the flow from the River Severn only had a local effect on the upstream part of the estuary, for both the residence and exposure time

Preoperative lung immune prognostic index predicts survival in patients with pancreatic cancer undergoing radical resection

BackgroundLung immune prognostic index (LIPI), a combination of derived neutrophil-to-lymphocyte ratio (dNLR) and lactate dehydrogenase (LDH), is currently attracting considerable interest as a potential prognostic indicator in many malignancies. Our study aimed to investigate the prognostic value of preoperative LIPI in patients with pancreatic ductal adenocarcinoma (PDAC) undergoing radical resection.MethodsWe retrospectively reviewed PDAC patients treated with radical resection from February 2019 to April 2021 at Chinese People's Liberation Army (PLA) general hospital. Based on the cut-off value of dNLR and LDH identified by X-tile, patients were divided into LIPI good and LIPI intermediate/poor group. Kaplan-Meier curve and log-rank test were used to compare the recurrence-free survival (RFS) and overall survival (OS) of the two groups. Univariate and multivariate Cox regression was used to identify the independent prognostic value of LIPI. Subgroup analysis was performed to identify specific population benefited from radical resection.ResultsA total of 205 patients were included and the median RFS and OS was 10.8 and 24.3 months, respectively. Preoperative LIPI intermediate/poor was related to worse RFS and OS (p < 0.05). Preoperative LIPI intermediate/poor, vascular invasion and no adjuvant chemotherapy were indicators of poor OS. Patients with LIPI intermediate/poor had worse OS especially among females and those with adjuvant chemotherapy (p < 0.05). Adjuvant chemotherapy related to better RFS and OS in patients with LIPI good (p < 0.05).ConclusionsPreoperative LIPI intermediate/poor can be an indicator of poor prognosis in patients with PDAC undergoing radical resection. LIPI good could be an effective marker of benefit from adjuvant chemotherapy. Larger studies are warranted for further validation

PD-1 inhibitors-based second-line therapy for metastatic gastric cancer

BackgroundMetastatic gastric cancer (MGC) patients with progression on first-line treatment still have poor outcomes on chemotherapy. The KEYNOTE-061 study demonstrated that pembrolizumab, a PD-1inhibitor, was not better than paclitaxel as second-line therapy for MGC. Herein, we explored the efficacy and safety of PD-1inhibitor based treatment for MGC patients in the second line.MethodsIn this observational, retrospective study, we enrolled MGC patients treated with anti-PD-1 based therapy as second-line in our hospital. We primarily assessed the treatment’s efficacy and safety. We also evaluated the relationship between clinical features and outcomes using univariate and multivariate analyses.ResultsWe enrolled 129 patients with an objective response rate (ORR) of 16.3% and a disease control rate (DCR) of 79.1%. Patients treated with PD-1inhibitor combined with chemotherapy and anti-angiogenic agents had ORR of 19.6% and higher DCR of 94.1%. The median progression-free survival (PFS) was 4.10 months, and the median overall survival (OS) was 7.60 months. In univariate analysis, patients treated with PD-1inhibitor combined with chemotherapy and anti-angiogenic agents and with prior anti-PD-1 history were significantly associated with favorable PFS and OS. In the multivariate analysis, different combination therapy and prior anti-PD-1 history were independent prognosis biomarkers for PFS and OS. Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 28 (21.7%) patients. Common adverse events (AEs) included fatigue, hyper/hypothyroidism, neutrophil decrease, anemia, skin reactions, proteinuria, and hypertension. We did not observe treatment-related deaths.ConclusionOur current results indicated that PD-1-inhibitor and chemo-anti-angiogenic agents combination therapy and prior PD-1 treatment history might improve clinical activity for GC immunotherapy as second-line treatment with acceptable safety profiles. Further studies are needed to verify those outcomes for MGC in other centers

A late Cambrian continental convergent margin in the North Qilian Orogenic Belt, Northwestern China: Geochemical and geochronological evidence from Hongtugou mafic rocks

The tectonic setting and subduction polarity of the early Paleozoic North Qilian Orogenic Belt (NQOB) in northwestern China is poorly constrained due to complex tectonic deformation. Mafic and ultramafic rocks in the South Ophiolite Belt of the NQOB are interpreted to be middle ocean ridge ophiolite or suprasubdcution zone ophiolite. To address this, we have conducted geochemical and geochronological investigations of the mafic rock sequence (cumulate gabbros, diabases, isotropic gabbros, and basalts) in Hongtugou in the South Ophiolite Belt. Trace element characteristics of the pillow basalts and the isotropic gabbros with enrichment of Th and La relative to Nb on the N-MORB normalized multi-element diagram are consistent with a suprasubduction setting, where similarities with the Panamanian proto-arc rocks suggest they formed shortly after subduction initiation. Major element modelling for cumulate gabbros and basalts indicates the hydrous condition of crystallization which further supports a suprasubduction setting. The Proterozoic zircon crystals captured in a cumulate gabbro and a diabase suggest this suprasubduction zone is a continental convergent margin. A weighted mean zircon SHRIMP age of 507 ± 6 Ma from an isotropic gabbro is consistent with crystallization ages of other mafic rocks in this belt. This suggests the North Qilian oceanic lithosphere subducted beneath the continent in the late Cambrian. Mafic rocks in this study along with the serpentinized peridotite do not fall into the category of ophiolite, despite displaying an ophiolite sequence

The Unified Equation of State for Dark Matter and Dark Energy

We assume that dark matter and dark energy satisfy the unified equation of state: $p=B(z)\rho$, with $p=p_{dE}$, $\rho=\rho_{dm}+\rho_{dE}$, where the pressure of dark matter $p_{dm}=0$ has been taken into account. A special function $B=-\frac{A}{(1+z)^{\alpha}}$ is presented, which can well describe the evolution of the universe. In this model, the universe will end up with a Big Rip. By further simple analysis, we know other choices of the function $B$ can also describe the universe but lead to a different doomsday.Comment: 7 pages, 3 figures, ws-mpla.cls, accepted by MPL

AC series arc fault detection based on RLC arc model and convolutional neural network

AC series arc faults in the power system can lead to electrical fires. However, the generalization performance of the determined detection method would be affected under unknown loads, as current features vary with loads. To address this issue, this paper presents a series arc fault detection method based on a high-frequency (HF) RLC arc model and one-dimensional convolutional neural network (1DCNN). By the current transformer used for receiving differential HF features (D-HFCT), current with complex features is firstly simplified and divided into different oscillation-signal types. Since the types of real D-HFCT data are limited, the RLC arc model is used to generate D-HFCT data with various types of oscillation features by adjusting load types, initial phase angles and Bernoulli-sequence frequencies. Then, the simulated data are adopted to train the 1DCNN model. Finally, the trained 1DCNN model can detect series arc faults under different types of real loads. Compared with the 1DCNN method driven by the limited types of real-current data, the presented method shows good generalization ability and achieves 99.33% average detection accuracy under nine types of unknown loads, which benefits from the training of simulated D-HFCT data with abundant HF oscillation features

The Real Scalar Field in Schwarzschild-de Sitter Spacetime

In this paper, the real scalar field equation in Schwarzschild-de Sitter spacetime is solved numerically with high precision. A method called polynomial approximation is introduced to derive the relation between the tortoise coordinate x and the radius r. This method is different from the tangent approximation [1] and leads to more accurate result. The Nariai black hole is then discussed in details. We find that the wave function is harmonic only near the horizons as I. Brevik and B. Simonsen [1] found. Howerver the wave function is not harmonic in the region of the potential peak, with amplitude increasing instead. Furthermore, we also find that, when cosmological constant decreases, the potential peak increases, and the maximum wave amplitude increases.Comment: 11 pages, 5 figures. To be published in volume 35(2003), G.R.

Influences of beta-alanine and l-histidine supplementation on growth performance, meat quality, carnosine content, and mRNA expression of carnosine-related enzymes in broilers

The current study investigated the effect of dietary L-histidine and beta-alanine sup-plementation on growth performance, meat quality, carnosine content, and gene expression of carnosine-related enzymes in broilers. A two-factor design was adopted in this study. A total of 640 1-day-old male broilers were assigned to eight treatments with factorial arrangement containing four levels of L-histidine (0, 650, 1300, or 1950 mg/kg) and two levels of beta-alanine (0 or 1200 mg/kg) supplementation; 0 mg/kg histidine and/or 0 mg/kg were treated as control groups. Each treatment including eight replicates with 10 birds each and the feeding trial lasted for 42 days. Dietary supple-mentation with L-histidine and beta-alanine did not affect average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) of broilers during the grower (22–42 days) and the entire phase (1–42 days), compared with the control group (p > 0.05). The only exception was a significantly reduced ADG in the 1950 mg/kg L-histidine group in the starter period (1–21 days, p < 0.05). L-Histidine at 1950 mg/kg significantly decreased redness (a*) and yellowness (b*) values of the meat at 45 min postmortem (p < 0.05), whereas it increased b* value and pH in breast muscle at 24 h postmortem. Moreover, dietary supplementation with beta-alanine alone or combination with L-histidine significantly increased ∆pH in breast muscle (p < 0.01). Dietary L-histidine markedly increased total superoxide dismutase activity and total antioxidant capacity (T-AOC) both in breast muscle (p < 0.01) and in plasma (p < 0.01), and it decreased malondialdehyde (MDA) concentration in breast muscle (p < 0.01). Dietary addition of beta-alanine, alone or combination, significantly increased T-AOC in breast muscle (p < 0.01) and markedly decreased MDA content both in breast muscle and in plasma (p < 0.01). Addition of L-histidine and beta-alanine significantly increased muscle peptide (carnosine and anserine) content (p < 0.05) and upregulated the expression of carno-sine synthase, transporter of carnosine/ L-histidine, and L-histidine decarboxylase genes (p < 0.05), with greater change occurring in the combination group of 1300 mg/kg L-histidine and 1200 mg/kg beta-alanine. Overall, dietary L-histidine and beta-alanine could improve meat quality and antioxi-dant capacity, enhance the carnosine and anserine content, and upregulate the gene expression of carnosine synthesis-related enzymes in broilers

The factors controlling along-arc and across-arc variations of primitive arc magma compositions: A global perspective

Arc volcanism is a key process influencing Earth’s climate, continental growth, and the formation of mineral deposits. Therefore in this contribution, we have compiled whole-rock geochemistry of frontal arc and rear-/back-arc basalts, crustal thickness, and slab parameters (e.g., slab age, slab dip, and convergence velocity) from global convergent margins to investigate the factors controlling along-arc and across-arc variations. Crustal thickness or lithosphere thickness plays a dominant role in elements immobile in aqueous fluids (e.g., Zr/Yb and Nb/Yb). The effect is imposed through mantle partial melting for both frontal arc and rear-/back-arc rocks. Slab thermal structure also affects these immobile elements and gives rise to along-arc variations. Both slab sediment and altered oceanic crust can melt especially in hot subduction zones which yield across-arc variations (e.g., Nd isotope). Aqueous fluids (represented by element ratios such as Ba/Nb and Sr/Nd) also show across-arc variations as they decrease toward rear-/back-arc. This meanwhile decreases mantle wedge melting as rear-/back-arcs show higher Zr/Yb and Nb/Yb. However, no correlations between aqueous fluids and slab parameters suggest aqueous fluids in arc rocks are controlled by complex processes. We summarize factors such as slab alteration, slab dehydration, and mantle metasomatism might impose an effect on the content of fluid mobile elements in arc rocks

Daily time-use patterns and obesity and mental health among primary school students in shanghai: a population-based cross-sectional study

Physical activity, screen viewing, sleep, and homework among children have been independently linked to health outcomes. However, few studies have assessed the independent associations between time spent in daily activities and children’s physical and mental health. This study describes time spent in four activities among primary school students in Shanghai, and examines the relationship between daily time-use patterns and obesity and mental health. The representative sample consists of 17,318 children aged 6–11 years in Shanghai. Time spent in moderate to vigorous physical activities (MVPA), screen viewing, sleep, and homework was measured by validated questionnaires. Logistic regressions were performed. We also fitted generalized additive models (GAM) and performed two-objective optimization to minimize the probability of poor mental health and obesity. In 2014, 33.7% of children spent ˂1 hour/day on MVPA, 15.6% spent ≥ 2 hours/day on screen viewing, 12.4% spent ˂ 9 hours/day on sleep, and 27.2% spent ≥ 2 hours/day on homework. The optimization results suggest that considering the 24-hour time limit, children face trade-offs when allocating time. A priority should be given to the duration of sleep and MVPA. Screen exposure should be minimized to save more time for sleep and other beneficial activities