Charge-parity (CP) violation in the tau-charm energy region is a promising area for sensitive tests of Standard Model (SM) predictions and searches for new, beyond the SM physics. A future Tau-Charm Facility that operates at center-of-mass energies between 2.0 and 7.0 GeV, with a peak luminosity of 0.5×1035 cm−2 s−1, would provide huge numbers of hadrons and tau (τ) leptons that are produced in low-background environments and with well understood kinematic properties. In this report, prospects for unique studies of CP violation in the decay of charmed hadrons, and in the production and decay of hyperons and τ leptons at a next-generation tau-charm facility are discussed. In addition, opportunities for improved tests of CPT invariance test in K0−K̄0 mixing are presented.
Two novel mononuclear copper(II) complexes, [Cu(H4N9-mpz)]Cl2·H2O (1) and [Cu(H4N9-mpz)](ClO4)2·2CH3OH (2), were synthesized for the first time utilizing the pyrazine-modulated long-chain pentapyridyltetraamine ligand, N2,N2′-(pyrazine-2,6-diyl)bis(N6-(pyridin-2-yl)pyridine-2,6-diamine) (H4N9-mpz). Both complexes were structurally characterized, and their in vitro cytotoxic activities were systematically evaluated. In each compound, the Cu(II) center is five-coordinate, adopting a slightly distorted trigonal bipyramidal geometry, with Addison distortion parameter τ values of 0.84 for complex (1) and 0.86 for complex (2). The H4N9-mpz ligand adopts an all-anti conformation, coordinating to the copper center as a pentadentate monohelical ligand. This trigonal bipyramidal coordination environment was further corroborated by electronic spectroscopy and the observation of "inverted-type" electron paramagnetic resonance (EPR) spectra. The cytotoxic effects of the free H4N9-mpz ligand and complexes 1 and 2 were evaluated against the DLD-1 and PC3 cancer cell lines, as well as the L929 healthy cell line, and compared with the reference drug cisplatin. Complex 2 exhibited superior antiproliferative activity compared to 1, yielding significantly lower IC50 values of 6.401 µM in DLD-1 cells and 2.956 µM in PC3 cells. However, toxicity profiles on healthy L929 cells revealed that complex 1 possesses a higher selectivity index than complex 2. Molecular docking simulations revealed distinct, target-dependent interaction profiles; the free ligand exhibited the highest predicted affinity toward Bcl-2, whereas the copper(II) complexes demonstrated more favorable docking scores against HSP90. These findings provide preliminary computational insights into potential ligand–protein interactions, prompting further experimental validation.
This work serves as a continuation of our preceding paper [28]. In that study, we presented a separable variable method to derive the Lebeau-Robbiano spectral inequality for a specific degenerate parabolic equation and subsequently employed it to demonstrate the null controllability of said equation when internal control is applied to an open subset. In the current paper, we reapply the separable variable method to attain the Lebeau-Robbiano spectral inequality for a different degenerate parabolic equation, and we substantiate the null controllability of this equation with internal control acting on a measurable subset. This approach may offer an alternative means of proving controllability results for degenerate parabolic equations.
Extratropical North Atlantic cooling has been tied to droughts over the Sahel in both paleoclimate observations and modeling studies. This study, which uses an atmospheric general circulation model (GCM) coupled to a slab ocean model that simulates this connection, explores the hypothesis that the extratropical North Atlantic cooling causes the Sahel droughts via an atmospheric teleconnection mediated by tropospheric cooling. The drying is also produced in a regional climate model simulation of the Sahel when reductions in air temperature (and associated geopotential height and humidity changes) from the GCM simulation are imposed as the lateral boundary conditions. This latter simulation explicitly demonstrates the central role of tropospheric cooling in mediating the atmospheric teleconnection from extratropical North Atlantic cooling. Diagnostic analyses are applied to the GCM simulation to infer teleconnection mechanisms. An analysis of top of atmosphere radiative flux changes diagnosed with a radiative kernel technique shows that extratropical North Atlantic cooling is augmented by a positive low cloud feedback and advected downstream, cooling Europe and North Africa. The cooling over North Africa is further amplified by a reduced greenhouse effect from decreased atmospheric specific humidity. A moisture budget analysis shows that the direct moisture effect and monsoon weakening, both tied to the ambient cooling and resulting circulation changes, and feedbacks by vertical circulation and evaporation augment the rainfall reduction. Cooling over the Tropical North Atlantic in response to the prescribed extratropical cooling also augments the Sahel drying. Taken together, they suggest a thermodynamic pathway for the teleconnection. The teleconnection may also be applicable to understanding the North Atlantic influence on Sahel rainfall over the twentieth century.
The relationship between earthquakes and fluid pressure variations remains debated, particularly regarding whether surface fluid anomalies reflect pore pressure changes at seismogenic depth. Anomalous fluid emissions at the Chung-lun mud pool in southwestern Taiwan were continuously monitored between 2008 and 2010, with quantitative analyses focusing on periods of stable observations from mid-2009 to late 2010 using water level sensors and a digital camera system. Long-term anomalies were characterized by sustained variations in water levels and changes in degassing behavior that were independent of precipitation. In four out of five cases, these anomalies occurred in close temporal association with nearby earthquakes, indicating a systematic temporal relationship rather than a simple random coincidence. Short-term variations were linked primarily to rainfall events, while long-term discharge anomalies are interpreted as being consistent with pore pressure perturbations at depth, based on indirect surface observations and the exclusion of meteorological and shallow hydrological controls, rather than direct measurements within the seismogenic zone. The results hypothesize that pore fluid overpressure at depth can modulate both fault stability and surface fluid discharge, consistent with the concept of fault valve behavior. Some anomalies were recorded prior to seismic events, suggesting that gradual increases in pore pressure may contribute to stress evolution in critically stressed thrust faults, although the coupling is not deterministic. The integration of instrumental and photographic observations at Chung-lun demonstrates the potential of mud pools as natural observatories for geodynamically induced interactions between tectonic activity and fluid transport and emission. It highlights their important role as valuable components in regional earthquake monitoring networks.
