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I explore a theory of transport and optical properties of strange metallic carriers in strongly correlated systems that follows from assuming that the diffusion constant has reached its quantum limit D=ℏ/m, and that such quantum carriers behave as distinguishable particles as they would in an electronic solid. These assumptions immediately lead to T-linear resistivities with apparent Planckian scattering rates and, extending to the frequency domain, to the stretched Drude peaks and ω/T scaling commonly observed in optical absorption experiments in strange metals. This behavior can be rationalized by observing that when the thermal de Broglie length λ_{dB} exceeds the mean-free path, the carrier motion can no longer be described in terms of random collisions of classical particles as assumed by Drude-Boltzmann theory and should be viewed instead as a sequence of projective measurements collapsing the wave function.
It is demonstrated that the widely used Lennard-Jones (LJ) potential in the mechanics of cross-linked polymers-and an oscillator based on it-can give rise to several notable phenomena: (i) The emergence of subharmonic and superharmonic oscillations across a broad range of driving force amplitudes; (ii) the presence of exponentially decaying amplitudes in the discrete part of the amplitude spectrum, associated with superharmonic components; (iii) the manifestation of multi-periodic, quasi-periodic, and chaotic regimes, depending on the amplitude of the driving force; (iv) the appearance of Feigenbaum cascades at transition zones between multi-periodic and chaotic behavior; and (v) the formation of strange attractors in the corresponding Poincaré sections, indicative of chaotic dynamics. The analysis is based on solving an autonomous system of three coupled first-order equations using the Adams-Bashforth-Moulton solver, which is well-suited for stiff dynamical systems. These findings offer deeper insight into the vibrational performance of seismic and vibration absorbers constructed from rubber-like materials modelled by LJ potentials.
The relationship between horses and humans is often described as cooperative and affective, yet empirical studies on horse-rider bond remain scarce. Previous findings on horse-human relationships yielded conflicting results on whether and how horses show bonding like behaviour toward their owners. We tested whether horses show partner-specific approach and proximity toward their primary rider compared with an unfamiliar experimenter in an adapted Strange Situation Test, and whether the rider's presence was associated with behavioural patterns indicative of safe haven and secure base effects. Thirty horse-rider pairs participated in a behavioural test conducted in an indoor riding arena, which included several episodes: recall by owner/experimenter, separation both from rider and experimenter, reunion with rider/experimenter, and exposure to a potentially frightening object in order to examine secure base effect. We compared horses' social behaviours (i.e. proximity, approach, gazing behaviour, etc.) toward their riders versus the unfamiliar experimenter, as well as their stress-related signals (i.e. manure, vocalization) across these episodes. We found that horses approached their rider significantly faster than the experimenter during recall and reunion episodes and spent significantly more time in close proximity to the rider across multiple contexts. Our findings indicate that horses' gazing behaviour is influenced more by the human's level of interactiveness than by familiarity. However, no conclusive evidence emerged for a "safe haven" effect during exposure to the frightening stimulus. Rider sex had no effect on the horses' social or stress related behaviours. These findings suggest that horses may form specific bonds with their riders, characterized by different social behaviours consistent with certain criteria of attachment theory. The study highlights the importance of incorporating socio-emotional components into analyses of human-horse relationships and underscores the relevance of comparative attachment frameworks in equine behaviour research.
Anti-Kpa is an irregular antibody of clinical significance directed against the red blood cell antigen Kpa of the Kell system. It is rare in the general population and, therefore, uncommon as a cause of transfusion or hemolytic complications. It has been documented in isolated cases, mainly in the context of alloimmunization after transfusion exposure or during pregnancy; its incidence in clinical practice is limited and can be difficult to detect in routine pre-transfusion testing, which could lead to failure to identify the antibody prior to transfusion. The production of Anti-Kpa antibodies is less common than antibodies against other Kell system antigens, such as anti-K. However, when generated, these antibodies can mediate hemolytic reactions in patients receiving incompatible blood and can cause hemolytic disease in the fetus since in addition to immune destruction of red blood cells, Kell system antibodies such as Anti-Kpa can cause suppression of fetal erythropoiesis, resulting in severe anemia.
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Background: Thyrotropin (TSH), even in the normal range, is associated with components of cardiometabolic syndrome. We aimed to assess the relation between TSH and cardiovascular (CV) risk in euthyroid patients with overweight/obesity without previous cardiac events. Methods: A total of 1588 subjects (1132 females, mean age 53 ± 14 years) were recruited. This was an observational study. TSH, body mass index, waist circumference (WC), creatinine, hepatic enzymes, homocysteine, C reactive protein, glycated hemoglobin, homeostatic model assessment for insulin resistance (HOMA-IR), basal and 2 h glucose and insulin, fibrinogen, uric acid, a complete blood count, a complete lipid profile, and blood pressure were measured in all subjects. The Atherosclerotic Cardiovascular Disease (ASCVD) risk score was calculated. Results: More severe degrees of obesity were associated with higher TSH quartiles; specifically, 33% of subjects with grade III obesity had TSH in the 75th percentile. Multiple regression showed that female gender (t-value 3.6, p < 0.001), HOMA-IR (1.9, ≤0.05) and aspartate transaminase (AST; 2.8, <0.01) represent independent determinant factors affecting TSH levels in the population at higher CV risk (intermediate-high ASCVD risk score > 7.5%; n = 709). Similarly, TSH determinants in subjects with central obesity (n = 1197, WC >102 cm males, >88 cm females) were female gender (2.2, <0.05), HOMA-IR (2.7, <0.01) and smoking habit (-2.3, <0.5). Moreover, there was no significant relationship between TSH and ASCVD risk score. Conclusions: Higher TSH levels in the euthyroid range are related to high degrees of obesity and some CV risk factors, in subjects at higher cardiometabolic risk; however, for the different weight and sign of CV determinants (e.g., smoking habit) on the TSH system, the ASCVD risk score cannot evidence this relationship.
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Overdoped cuprate superconductors are strange metals above their superconducting transition temperature. In such materials, the electrical resistivity has a strong linear dependence on temperature (T) and electrical current is not carried by electron quasiparticles as in conventional metals. Here we demonstrate that the strange metal behaviour co-exists with strongly temperature-dependent critical spin fluctuations showing dynamical scaling across the cuprate phase diagram. Our neutron scattering observations and the strange metal behaviour are consistent with a spin density wave quantum phase transition in a metal with spatial disorder in the tuning parameter. Numerical computations using a theory of spin density waves in a disordered metal yield an extended 'Griffiths phase' with scaling properties in agreement with experimental observations. Thus we establish that low-energy spin excitations and spatial disorder are central to the strange metal behaviour.
While the ability to understand others' mental states (Theory of Mind, ToM) is fundamental for social interactions, its relationship with executive functions (EF) in adults with attention-deficit/hyperactivity disorder (ADHD) remains under-explored. This study investigated ToM abilities and three core EFs (working memory, response inhibition, and planning) in adults with ADHD compared to a healthy control group. Thirty adults with ADHD were matched with thirty controls on age, gender, IQ, and education. ToM was assessed using the Strange Stories Test. EFs were evaluated using four subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB): Spatial Span (SSP) for short-term memory, Spatial Working Memory (SWM) for working memory, Stockings of Cambridge (SOC) for planning, and Stop Signal Task (SST) for response inhibition. Mann-Whitney U tests compared groups, and Spearman's rho examined ToM-EF relationships. Individuals with ADHD showed significantly poorer performance on the Strange Stories Test and all CANTAB subtests compared to controls. Within the ADHD group, most EF components showed no significant correlation with ToM scores. These findings confirm deficits in both ToM and EFs in adults with ADHD. The lack of strong correlations suggests that ToM difficulties may represent a distinct cognitive domain, independent of core EF impairments.
The electric dipole moment (EDM) of baryons provides a sensitive probe of CP-violating interactions beyond the standard model. Motivated by the recent BESIII measurement on the Λ hyperon EDM [Ablikim et al., arXiv:2506.19180.], we present the first perturbative QCD analysis of the Λ EDM form factor to elucidate its origin in CP-violating quark dipole interactions. In particular, we derive a QCD factorization formula that relates the Λ EDM form factor to quark EDMs and chromoelectric dipole moments through convolutions with light-cone distribution amplitudes of Λ. These connections allow us to extract constraints on CP-violating dipole couplings from current and future hyperon EDM measurements. Our numerical analysis demonstrates that the Λ EDM exhibits unique sensitivity to the strange-quark chromoelectric dipole moment, providing complementary information to that obtained from the neutron EDM.
Recent laboratory experimental work has shown that heating and cooling processes exhibit intrinsic asymmetry, with heating occurring more efficiently than cooling. Two decades earlier, nonequilibrium molecular dynamics simulations addressed the topic of heating one side of a computational cell while cooling the other side by applying two different thermostats, producing a sinusoidal temperature profile. We revisit the theory underlying those computer calculations and show how it accurately predicts the laboratory results. Recent realizations of a simple two-dimensional one-particle cell model give surprisingly relevant results, where two Nosé-Hoover thermostats are applied to the two directions (x and y) at two temperatures, Tx ≥ Ty. At equilibrium, the thermostatting rate variables ξx and ξy are identical, while under nonequilibrium temperature differences, the heating variable (ξx) is weaker than the cooling one (ξy), demonstrating the ratio of thermostat effort to thermal bias, just as predicted by theory: ⟨ξx⟩/⟨ξy⟩ = -Ty/Tx. We relate this to the negative rate of change in entropy of the nonequilibrium system that accompanies the contraction of phase space onto a fractal strange attractor of lower dimension. Histograms of the thermostat variables reveal the stark differences between equilibrium and nonequilibrium heat flow. At equilibrium, the cell-model ξ-distributions are both Gaussians centered at zero. We redid much earlier many-body simulations of a Nosé-Hoover thermostatted fluid at equilibrium, which reported that the distribution was biased toward heating; we discovered that the prior work suffered from systematic integration error. In fact, we find that the distribution at equilibrium is a totally symmetric Gaussian for many-body systems, in agreement with the cell model. Under nonequilibrium conditions, when Tx > Ty, the simple 2D cell model clearly demonstrates the microscopic origin of heating-cooling asymmetry, thereby strongly confirming the results of real-world laboratory experiments.
Research on interactions between child and environmental factors in the development of infant disorganized attachment is relatively limited. Using predictive modeling, we explored how child, maternal, and family-related variables jointly predicted attachment disorganization in 204 infant-mother dyads. Almost all mothers were diagnosed with postpartum depression. We measured child, maternal, and family-related variables with validated questionnaires when infants were M = 2.94 months and attachment (dis)organization with the Strange Situation Procedure at M = 13.84 months. Lasso regression identified relevant predictors and classification trees explored their interactions. Classification trees achieved moderate overall accuracy (.65). Both methods converged on the interaction between firstborn status and high parenting stress attributed to child characteristics as particularly relevant. Findings require replication in larger pooled datasets including additional established risk factors for disorganized attachment. We highlight the value of predictive modeling in attachment research and evaluating non-linear associations between child and parental characteristics and attachment disorganization.
We review a theoretical framework for the cuprate superconductors, rooted in a fractionalized Fermi liquid (FL*) description of the intermediate-temperature pseudogap phase at low doping. The FL* theory predicted hole pockets each of fractional areap/8at hole dopingp, in contrast to the areap/4in spin density wave theory. Magnetotransport measurements, including observation of the Yamaji angle, show clear evidence of hole pocket quasiparticles which can tunnel coherently between square lattice layers, and are consistent with the FL* description. The FL* phase of a single-band model is described using a layer construction with a pair of ancilla qubits on each site: the Ancilla layer model (ALM). Its mean field theory yields hole pockets of areap/8, and matches the gapped photoemission spectrum in the anti-nodal region of the Brillouin zone. Fluctuations are described by the SU(2) gauge theory of a background spin liquid with critical Dirac spinons. A Monte Carlo study of the thermal SU(2) gauge theory transforms the hole pockets into Fermi arcs in photoemission. One route to confinement of FL* upon lowering temperature yields ad-wave superconductor via a Kosterlitz-Thouless transition ofh/(2e)vortices, with nodal Bogoliubov quasiparticles featuring anisotropic velocities and vortices surrounded by charge order halos. An alternative route yields a charge-ordered metallic state that has quantum oscillations consistent with observations. These confinement transitions are driven by the condensation of a SU(2) fundamental Higgs field, which also provides a fractionalized description of intertwined orders. Increasing doping from the FL* phase in the ALM drives a transition to a conventional FL at large doping, passing through an intermediate strange metal regime. We formulate a theory of the FL*-FL metal-metal transition without a symmetry-breaking order parameter, using a critical quantum 'charge' liquid of mobile electrons in the presence of disorder, developed via an extension of the Sachdev-Ye-Kitaev model to two spatial dimensions. At low temperatures, and across optimal and over doping, we address the regimes of extended non-FL behavior by Griffiths effects near quantum phase transitions in disordered metals.Partly based on lectures by S S atBoulder School 2025, Dynamics of Strongly Correlated Electrons, 14-18 July.Lecture videos.Joint ICTP-WE Heraeus School and Workshop on Advances in Quantum Matter: Pushing the Boundaries, ICTP, Trieste, 4, 6 August 2025.Lecture videos.School on Quantum Dynamics of Matter, Light and Information, ICTP, Trieste, 18, 19 August 2025.Lecture videos.Croucher Advanced Study Institute for Fractional Chern Insulators, University of Hong Kong, 4, 5 September 2025.Lecture slides.Advanced School and Conference on Quantum Matter, ICTP Trieste, 1-12 December 2025.Lecture Notes.Lecture videos.
Early caregiving relationships shape the coordination of stress and immune systems, yet their biological correlates in early infancy remain insufficiently understood. This study examined whether attachment relationships are associated with mucosal immune function and stress physiology. Thirty-five infants (mean age = 16.6 months) were classified as securely or insecurely attached using the Strange Situation Procedure. Salivary secretory IgA (SIgA) was collected in the morning and afternoon at two time points, and cumulative cortisol was quantified from hair samples. Securely attached infants showed higher morning SIgA concentrations and more stable intra-day immune profiles compared with insecurely attached children. No group-level differences were observed for cumulative cortisol, but immune-endocrine associations revealed that higher cortisol was linked to lower morning SIgA and greater intra-day fluctuation. Bayesian regression models supported consistent directional effects, and machine-learning analyses confirmed that SIgA-based features accurately predict attachment type. Our findings support the idea that secure attachment fosters stable coordination between immune and endocrine systems during a critical stage of early development. These effects could be readily captured at very early stages of life, identifying SIgA as a potential biomarker of early socioemotional environments. By integrating behavioral, immunological, and computational approaches, this study provides evidence for the biological embedding of attachment and highlights the potential of non-invasive biomarkers to support early identification of psychosocial vulnerability.
A 63-year-old male patient with chronic obstructive pulmonary disease (COPD) was examined using cardiac computed tomography (CT) and transesophageal echocardiography (TEE) to estimate the presence of chronic thrombi, such as left atrial appendage (LAA) thrombi and pulmonary vein thrombi (PVTs). The patient presented with a strange thrombus-containing vessel over the anterior surface of the heart, which did not appear to be a coronary vein. The abnormal wall of the ascending aorta (AAo) was difficult to differentiate from the AAo thrombi, and a dark (low echogenic) mass was observed in the center of the abnormal AAo wall on TEE. The origin of the mass was unknown but could potentially be associated with atherosclerosis, a Valsalva aneurysm, aortic dissection, an aortic aneurysm, or aortic valve disease. The relationship between these factors and the coronary artery, as well as whether apixaban (a factor Xa inhibitor) could cure the cleft in the mass, remains unclear.