Hydrothermal Geochemistry and Mineralizing Processes in the T Zone, Thor Lake Rare-element Deposit, Northwest Territories

The Thor Lake rare-metal (Y-REE-Nb-Ta-Zr-Be) deposit, located about 100 kilometers southeast of Yellowknife, Northwest Territories, Canada, is regarded as one of the largest high field strength elements (HFSE, including Nb, Ta, Zr, Hf, Ti, Y, and the lanthanides) deposits and hosted by alkaline granite and syenite. The T Zone deposit, one of the main mineralized zones at Thor Lake, is characterized by HFSE mineralization that has intimate connection to hydrothermal activities. The T Zone at Thor Lake provides an excellent opportunity to assess the mobility and precipitation of HFSE in magmatic-hydrothermal systems. The T Zone has been identified as a pegmatite that experienced multiple alteration stages. Most HFSE minerals were hydrothermally formed, as indicated by their occurrence in pseudomorphs. The most important precursor minerals for those HFSE-rich and Be-rich pseudomorphs are aegirine and mica-group minerals. The HFSE concentrations in aegirine and mica are not sufficiently high. Therefore, a dissolution-reprecipitation model cannot explain the presence of zircon and other HFSE minerals that pseudomorph aegirine. Rather, the addition of HFSE by hydrothermal fluids is required. Mass transfer calculations show that HFSE were added or removed during different alteration events. Related to the identified alteration events, the remobilization patterns of HFSE reveal that transport and precipitation of HFSE in the T Zone was likely caused by fluids with different characteristics. Magmatic and various types of hydrothermal zircon are characterized by different trace element chemistry. Titanium-in-zircon geothermometer was employed to constrain the mineralizing temperatures of the T Zone. The crystallization temperatures for the magmatic zircon from the host granite range from 792 to 1195 °C. Extremely high Ti concentrations in hydrothermal zircon from the T Zone prevent the application of Ti-in-zircon geothermometry. Primary fluid inclusion assemblages (FIAs) related to precipitation of various HFSE minerals in the T Zone were identified. Microthermometric analysis has revealed that there were likely two populations of fluids in the T Zone. According to fluid inclusion LA-ICP-MS analysis and EDS decrepitate analysis, the fluids responsible for HFSE transport in the T Zone contain significant HFSE, are aqueous and dominated by Na and Cl with trace amounts of CO 2 and CH 4

Abrupt climate transition of icy worlds from snowball to moist or runaway greenhouse

Ongoing and future space missions aim to identify potentially habitable planets in our Solar System and beyond. Planetary habitability is determined not only by a planet's current stellar insolation and atmospheric properties, but also by the evolutionary history of its climate. It has been suggested that icy planets and moons become habitable after their initial ice shield melts as their host stars brighten. Here we show from global climate model simulations that a habitable state is not achieved in the climatic evolution of those icy planets and moons that possess an inactive carbonate-silicate cycle and low concentrations of greenhouse gases. Examples for such planetary bodies are the icy moons Europa and Enceladus, and certain icy exoplanets orbiting G and F stars. We find that the stellar fluxes that are required to overcome a planet's initial snowball state are so large that they lead to significant water loss and preclude a habitable planet. Specifically, they exceed the moist greenhouse limit, at which water vapour accumulates at high altitudes where it can readily escape, or the runaway greenhouse limit, at which the strength of the greenhouse increases until the oceans boil away. We suggest that some icy planetary bodies may transition directly to a moist or runaway greenhouse without passing through a habitable Earth-like state.Comment: 31 pages, 4 figures, 2 supplementary tables, and 9 supplementary figure

Watermarking for Out-of-distribution Detection

Out-of-distribution (OOD) detection aims to identify OOD data based on representations extracted from well-trained deep models. However, existing methods largely ignore the reprogramming property of deep models and thus may not fully unleash their intrinsic strength: without modifying parameters of a well-trained deep model, we can reprogram this model for a new purpose via data-level manipulation (e.g., adding a specific feature perturbation to the data). This property motivates us to reprogram a classification model to excel at OOD detection (a new task), and thus we propose a general methodology named watermarking in this paper. Specifically, we learn a unified pattern that is superimposed onto features of original data, and the model's detection capability is largely boosted after watermarking. Extensive experiments verify the effectiveness of watermarking, demonstrating the significance of the reprogramming property of deep models in OOD detection

Research and Implementation of Instrument System on a Light-Duty Electric Aircraft Simulator

Considering the demands of the instrument system on a light-duty electric aircraft simulator, a semi-physical simulation instrument system, which is based on virtual reality and microcontroller technologies, is designed and implemented. Meanwhile, some key technologies are discussed and a general development method is put forward in this paper. After being completed, this simulated instrument system is connected with the flight-computing system to test its performances. The results show that it has real effect, stable operation and real time response. In practice, the instrument system not only meets the demands of the light-duty electric aircraft simulator, but also can be seen as a certain reference to develop the instrument system of other aircraft simulators

Dual-factor Synergistically Activated ESIPT-based Probe:Differential Fluorescence Signals to Simultaneously Detect α-Naphthyl Acetate and Acid α-Naphthyl Acetate Esterase

[Image: see text] α-Naphthyl acetate esterase (α-NAE) and acid α-naphthyl acetate esterase (ANAE), a class of special esterases, are important for lymphocyte typing and immunocompetence-monitoring. As such, the simultaneous detection of α-NAE and ANAE has become a target to effectively improve the accuracy in lymphocyte typing. Therefore, we developed a dual-factor synergistically activated ESIPT-based probe (HBT-NA) to detect α-NAE and ANAE sensitively, rapidly, and simultaneously in a differential manner. HBT-NA exhibits differential fluorescence signal outputs toward small changes of α-NAE and ANAE activities. HBT-NA displays a weak fluorescence signal at 392 nm over a pH range from 6.0 to 7.4. However, when it interacts with α-NAE (0–25 U) at pH = 7.4, the fluorescence intensity at 392 nm enhanced linearly within 60 s (F(392 nm)/F0(392 nm) = 0.042 C(α-NAE) + 1.1, R(2) = 0.99). Furthermore, HBT-NA emits ratiometric fluorescence signals (F(505 nm)/F(392 nm)) for ANAE (0–25 U) at pH = 6.0 within 2.0 min, exhibiting a good linear relationship (F(505 nm)/F(392 nm) = 0.83C(ANAE) – 1.75, R(2) = 0.99). The differential fluorescence signals can be used to simultaneously detect the activities of α-NAE and ANAE in solutions and complex living organisms. More importantly, based on the differential fluorescence signals toward α-NAE and ANAE, T lymphocytes and B lymphocytes could be successfully typed and differentiated among nontyped lymphocytes, facilitating the real-time evaluation of their immune functions using flow cytometry. Hence, HBT-NA could be used for the ultrasensitive detection of the enzyme activities of α-NAE and ANAE, the real-time precise typing of lymphocytes, and the monitoring of immunocompetence