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The emergence of new nuclear aspirants has posed a great threat to the post-Cold War global non-proliferation regime. These states have adopted a nuclear hedging strategy that has been deemed both strategically risky and politically difficult to maintain. Yet, hedging has not automatically resulted in nuclearisation. We analyse the conditions under which a nuclear hedger shifts its nuclear policy towards one of restraint. Drawing insights from prospect theory, we argue that a nuclear policy shift occurs when a nuclear hedger gains an asymmetric leverage vis-à-vis its adversary. Specifically, a hedging strategy that is based on loss aversion will only be abandoned when a shift in the nuclear aspirant's reference point occurs during negotiations. To test our theoretical arguments, we conduct an in-depth case study of North Korea's nuclear policies throughout the 1990s and 2000s. The empirical study of the changes in North Korea's negotiating stance during the Agreed Framework negotiations and the Six-Party Talks supports our asymmetric leverage thesis. We conclude with broad policy implications for the non-proliferation regime.

The last two decades have seen a slow but steady increase in nuclear armed states, and in the seemingly less constrained policy goals of some of the newer \"rogue\" states in the international system. The authors ofOn Limited Nuclear War in the 21st Century argue that a time may come when one of these states makes the conscious decision that using a nuclear weapon against the United States, its allies, or forward deployed forces in the context of a crisis or a regional conventional conflict may be in its interests. They assert that we are unprepared for these types of limited nuclear wars and that it is urgent we rethink the theory, policy, and implementation of force related to our approaches to this type of engagement. Together they critique Cold War doctrine on limited nuclear war and consider a number of the key concepts that should govern our approach to limited nuclear conflict in the future. These include identifying the factors likely to lead to limited nuclear war, examining the geopolitics of future conflict scenarios that might lead to small-scale nuclear use, and assessing strategies for crisis management and escalation control. Finally, they consider a range of strategies and operational concepts for countering, controlling, or containing limited nuclear war.

Targeting at the problem of wind power accommodation in coastal areas with large-scale wind power and nuclear power, the optimal scheduling method of wind-nuclear coordination is studied. The wind power output and the load following of nuclear power are analysed for the complementary characteristics. Based on the economic optimization of power system, an optimal scheduling method of wind-nuclear power is proposed, where the constraints of time coupling and load following depth are considered to meet the safety requirement of nuclear power operation. Simulation results of a numerical example verify the validity and effectiveness of the method. Results show that the wind power output is complementary with the load following of nuclear power; the optimal scheduling method of wind-nuclear coordination can comprehensively balance the operation cost and environment benefits, which realises the improvement of both the overall economy and the wind power accommodation.

The f ( Q ) theories of modified gravity arise from the consideration of non-metricity as the basic geometric quantity, and have been proven to be very efficient in describing the late-time Universe. We use the Big Bang Nucleosynthesis (BBN) formalism and observations in order to extract constraints on various classes of f ( Q ) models. In particular, we calculate the deviations that f ( Q ) terms bring on the freeze-out temperature T f in comparison to that of the standard Λ CDM evolution, and then we impose the observational bound on δ T f T f to extract constraints on the involved parameters of the considered models. Concerning the polynomial model, we show that the exponent parameter should be negative, while for the power-exponential model and the new hyperbolic tangent-power model we find that they pass the BBN constraints trivially. Finally, we examine two DGP-like f ( Q ) models, and we extract the bounds on their model parameters. Since many gravitational modifications, although able to describe the late-time evolution of the Universe, produce too-much modification at early times and thus fall to pass the BBN confrontation, the fact that f ( Q ) gravity can safely pass the BBN constraints is an important advantage of this modified gravity class.

Dysregulated prefrontal control over amygdala is engaged in the pathogenesis of psychiatric diseases including depression and anxiety disorders. Here we show that, in a rodent anxiety model induced by chronic restraint stress (CRS), the dysregulation occurs in basolateral amygdala projection neurons receiving mono-directional inputs from dorsomedial prefrontal cortex (dmPFC→BLA PNs) rather than those reciprocally connected with dmPFC (dmPFC↔BLA PNs). Specifically, CRS shifts the dmPFC-driven excitatory-inhibitory balance towards excitation in the former, but not latter population. Such specificity is preferential to connections made by dmPFC, caused by enhanced presynaptic glutamate release, and highly correlated with the increased anxiety-like behavior in stressed mice. Importantly, low-frequency optogenetic stimulation of dmPFC afferents in BLA normalizes the enhanced prefrontal glutamate release onto dmPFC→BLA PNs and lastingly attenuates CRS-induced increase of anxiety-like behavior. Our findings thus reveal a target cell-based dysregulation of mPFC-to-amygdala transmission for stress-induced anxiety. Dysregulated prefrontal control over amygdala has been implicated in the etiology of stress-related psychiatric disorders. Here, the authors show that the dysregulation preferentially occurs in amygdala neurons that are mono- but not bi-directionally connected with dorsomedial prefrontal cortex.

Cells sense the extracellular environment and mechanical stimuli and translate these signals into intracellular responses through mechanotransduction, which alters cell maintenance, proliferation, and differentiation. Here we use a mouse model of trauma-induced heterotopic ossification (HO) to examine how cell-extrinsic forces impact mesenchymal progenitor cell (MPC) fate. After injury, single-cell (sc) RNA sequencing of the injury site reveals an early increase in MPC genes associated with pathways of cell adhesion and ECM-receptor interactions, and MPC trajectories to cartilage and bone. Immunostaining uncovers active mechanotransduction after injury with increased focal adhesion kinase signaling and nuclear translocation of transcriptional coactivator TAZ, inhibition of which mitigates HO. Similarly, joint immobilization decreases mechanotransductive signaling, and completely inhibits HO. Joint immobilization decreases collagen alignment and increases adipogenesis. Further, scRNA sequencing of the HO site after injury with or without immobilization identifies gene signatures in mobile MPCs correlating with osteogenesis, and signatures from immobile MPCs with adipogenesis. scATAC-seq in these same MPCs confirm that in mobile MPCs, chromatin regions around osteogenic genes are open, whereas in immobile MPCs, regions around adipogenic genes are open. Together these data suggest that joint immobilization after injury results in decreased ECM alignment, altered MPC mechanotransduction, and changes in genomic architecture favoring adipogenesis over osteogenesis, resulting in decreased formation of HO.

A review is made of constraints on the nuclear symmetry energy parameters arising from nuclear binding energy measurements, theoretical chiral effective field predictions of neutron matter properties, the unitary gas conjecture, and measurements of neutron skin thicknesses and dipole polarizabilities. While most studies have been confined to the parameters SV and L, the important roles played by, and constraints on Ksym, or, equivalently, the neutron matter incompressibility KN, are discussed. Strong correlations among SV,L, and KN are found from both nuclear binding energies and neutron matter theory. However, these correlations somewhat differ in the two cases, and those from neutron matter theory have smaller uncertainties. To 68% confidence, it is found from neutron matter theory that SV=32.0±1.1 MeV, L=51.9±7.9 MeV and KN=152.2±38.1 MeV. Theoretical predictions for neutron skin thickness and dipole polarizability measurements of the neutron-rich nuclei 48Ca, 120Sn, and 208Pb are compared to recent experimental measurements, most notably the CREX and PREX neutron skin experiments from Jefferson Laboratory. By themselves, PREX I+II measurements of 208Pb and CREX measurement of 48Ca suggest L=121±47 MeV and L=−5±40 MeV, respectively, to 68% confidence. However, we show that nuclear interactions optimally satisfying both measurements imply L=53±13 MeV, nearly the range suggested by either nuclear mass measurements or neutron matter theory, and is also consistent with nuclear dipole polarizability measurements. This small parameter range implies R1.4=11.6±1.0 km and Λ1.4=228−90+148, which are consistent with NICER X-ray and LIGO/Virgo gravitational wave observations of neutron stars.

We present an update of the global fit of the Standard Model electroweak sector to latest experimental results. We include new kinematic top quark and W boson mass measurements from the LHC, a \\[\\sin \\!^2\\theta ^{\\ell }_{\\mathrm{eff}}\\] result from the Tevatron, and a new evaluation of the hadronic contribution to \\[\\alpha (M_Z^2)\\]. We present tests of the internal consistency of the electroweak Standard Model and updated numerical predictions of key observables. The electroweak data combined with measurements of the Higgs boson coupling strengths and flavour physics observables are used to constrain parameters of two-Higgs-doublet models.

Head motion causes artifacts in functional magnetic resonance imaging (fMRI) scans, a problem especially relevant for task-free resting state paradigms and for developmental, aging, and clinical populations. In a cohort spanning 7–28 years old (mean age 15) we produced customized head-anatomy-specific Styrofoam molds for each subject that inserted into an MRI head coil. We scanned these subjects under two conditions: using our standard procedure of packing the head coil with foam padding about the head to reduce head motion, and using the customized molds to reduce head motion. In 12 of 13 subjects, the molds reduced head motion throughout the scan and reduced the fraction of a scan with substantial motion (i.e., volumes with motion notably above baseline levels of motion). Motion was reduced in all 6 head position estimates, especially in rotational, left-right, and superior-inferior directions. Motion was reduced throughout the full age range studied, including children, adolescents, and young adults. In terms of the fMRI data itself, quality indices improved with the head mold on, scrubbing analyses detected less distance-dependent artifact in scans with the head mold on, and distant-dependent artifact was less evident in both the entire scan and also during only low-motion volumes. Subjects found the molds comfortable. Head molds are thus effective tools for reducing head motion, and motion artifacts, during fMRI scans. •Scanned 13 subjects ages 7–28 with and without custom head molds.•Overall motion reduced by head molds.•Fraction of scan with large motion reduced by head molds.•Small motions throughout scan reduced by head molds.•Motion artifact reduced by head molds.

Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. No conclusive signal, despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, has been detected so far. This situation might change in near future due to the advent of one/multi-TON Direct Detection experiments. We thus, find it timely to provide a review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities. Collider and Indirect Detection, nevertheless, will not be neglected when they represent a complementary probe.