Correlation driven near-flat band Stoner excitations in a Kagome magnet.

Among condensed matter systems, Mott insulators exhibit diverse properties that emerge from electronic correlations. In itinerant metals, correlations are usually weak, but can also be enhanced via geometrical confinement of electrons, that manifest as 'flat' dispersionless electronic bands. In the fast developing field of topological materials, which includes Dirac and Weyl semimetals, flat bands are one of the important components that can result in unusual magnetic and transport behaviour. To date, characterisation of flat bands and their magnetism is scarce, hindering the design of novel materials. Here, we investigate the ferromagnetic Kagomé semimetal Co3Sn2S2 using resonant inelastic X-ray scattering. Remarkably, nearly non-dispersive Stoner spin excitation peaks are observed, sharply contrasting with the featureless Stoner continuum expected in conventional ferromagnetic metals. Our band structure and dynamic spin susceptibility calculations, and thermal evolution of the excitations, confirm the nearly non-dispersive Stoner excitations as unique signatures of correlations and spin-polarized electronic flat bands in Co3Sn2S2. These observations serve as a cornerstone for further exploration of band-induced symmetry-breaking orders in topological materials.

Quadrupolar magnetic excitations in an isotropic spin-1 antiferromagnet.

The microscopic origins of emergent behaviours in condensed matter systems are encoded in their excitations. In ordinary magnetic materials, single spin-flips give rise to collective dipolar magnetic excitations called magnons. Likewise, multiple spin-flips can give rise to multipolar magnetic excitations in magnetic materials with spin S ≥ 1. Unfortunately, since most experimental probes are governed by dipolar selection rules, collective multipolar excitations have generally remained elusive. For instance, only dipolar magnetic excitations have been observed in isotropic S = 1 Haldane spin systems. Here, we unveil a hidden quadrupolar constituent of the spin dynamics in antiferromagnetic S = 1 Haldane chain material Y2BaNiO5 using Ni L3-edge resonant inelastic x-ray scattering. Our results demonstrate that pure quadrupolar magnetic excitations can be probed without direct interactions with dipolar excitations or anisotropic perturbations. Originating from on-site double spin-flip processes, the quadrupolar magnetic excitations in Y2BaNiO5 show a remarkable dual nature of collective dispersion. While one component propagates as non-interacting entities, the other behaves as a bound quadrupolar magnetic wave. This result highlights the rich and largely unexplored physics of higher-order magnetic excitations.

Exploring attention to the Canadian 24-Hour Movement Guidelines for Children and Youth using eye-tracking: A randomized control trial.

BACKGROUND: The Canadian 24-Hour Movement Guidelines for Children and Youth ("Guidelines") not only pioneered the notion of an integrated movement continuum from sleep to vigorous-intensity physical activity but also introduced a new branded Guideline visual identity. OBJECTIVES: This study evaluated youths' (N = 46) attention to and thoughts about the Guidelines and the brand. DESIGN: A cross-sectional between-participants randomized intervention design was used. SAMPLE: Canadian youth between 10 and 17 years of age comprised the study sample. INTERVENTIONS: Participants were randomly assigned to view either branded Guidelines (n = 26) or unbranded Guidelines (n = 20). Youths' eye-movements (e.g., dwell time, fixation count) were recorded during Guideline viewing. Participants completed a follow-up survey assessing brand perceptions and Guideline cognitions. RESULTS: The branded Guidelines neither drew greater overall attention nor led to more positive brand perceptions or Guideline cognitions compared to the unbranded Guidelines. CONCLUSIONS: Exploratory analyses provide valuable, yet preliminary insight into how branding and Guideline content may shape how Guidelines are perceived and acted upon. These findings inform an agenda for future health education resources.

An Experimental Test of a Generic Messaging Approach for the Canadian 24-Hour Movement Guidelines for Adults.

Many Canadian adults are failing to meet national recommendations for physical activity, sedentary behavior, and sleep (i.e., movement behaviors). Existing messaging strategies focus on thresholds, which may be unrealistic to the target audience. This article explores the utility of a novel messaging approach - generic messages - as a gateway to enhance adults' confidence to meet the Canadian 24-Hour Movement Guidelines for Adults ('Guidelines'). In an online study, adult Guideline end-users (N = 249) completed pre-, post- and two-week surveys following exposure to generic or threshold Guideline promotional materials. Hierarchal linear regressions predicting adults' confidence to meet the Guidelines revealed an activity status by experimental condition interaction. Post hoc analyses indicated low active adults exposed to generic messages had greater confidence to meet the Guidelines compared to low active adults exposed to threshold messages. Message processing was greater among adults exposed to the generic than threshold materials. This research highlights the importance of presenting achievable behavioral goals through generic messages. Specifically, this study demonstrated that generic messaging enhances self-efficacy beliefs among low active Canadian adults. Organizations promoting behavior change among adults with low levels of behavioral engagement should consider the use of generic motivational messages within a segmented health communication campaign.

Unraveling the Orbital Physics in a Canonical Orbital System KCuF_{3}.

We explore the existence of the collective orbital excitations, orbitons, in the canonical orbital system KCuF_{3} using the Cu L_{3}-edge resonant inelastic x-ray scattering. We show that the nondispersive high-energy peaks result from the Cu^{2+} dd orbital excitations. These high-energy modes display good agreement with the ab initio quantum chemistry calculation, indicating that the dd excitations are highly localized. At the same time, the low-energy excitations present clear dispersion. They match extremely well with the two-spinon continuum following the comparison with Müller ansatz calculations. The localized dd excitations and the observation of the strongly dispersive magnetic excitations suggest that the orbiton dispersion is below the resolution detection limit. Our results can reconcile with the strong local Jahn-Teller effect in KCuF_{3}, which predominantly drives orbital ordering.

Strong Superexchange in a d

The discovery of superconductivity in a d^{9-δ} nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni L-edge and O K-edge spectroscopy of the reduced d^{9-1/3} trilayer nickelates R_{4}Ni_{3}O_{8} (where R=La, Pr) and associated theoretical modeling. A magnon energy scale of ∼80 meV resulting from a nearest-neighbor magnetic exchange of J=69(4) meV is observed, proving that d^{9-δ} nickelates can host a large superexchange. This value, along with that of the Ni-O hybridization estimated from our O K-edge data, implies that trilayer nickelates represent an intermediate case between the infinite-layer nickelates and the cuprates. Layered nickelates thus provide a route to testing the relevance of superexchange to nickelate superconductivity.

Resonant inelastic x-ray spectroscopy on UO2 as a test case for actinide materials.

Resonant inelastic x-ray spectroscopy at the uranium N4 absorption edge at 778 eV has been used to reveal the excitations in UO2 up to 1 eV. The earlier (1989) studies by neutron inelastic scattering of the crystal-field states within the 3H4 multiplet are confirmed. In addition, the first excited state of the 3F2 multiplet at ∼520 meV has been established, and there is a weak signal corresponding to the next excited state at ∼920 meV. This represents a successful application of soft x-ray spectroscopy to an actinide sample, and resolves an open question in UO2 that has been discussed for 50 years. The technique is described and important caveats are drawn about possible future applications.

Strongly Correlated Charge Density Wave in La_{2-x}Sr_{x}CuO_{4} Evidenced by Doping-Dependent Phonon Anomaly.

The discovery of charge-density-wave-related effects in the resonant inelastic x-ray scattering spectra of cuprates holds the tantalizing promise of clarifying the interactions that stabilize the electronic order. Here, we report a comprehensive resonant inelastic x-ray scattering study of La_{2-x}Sr_{x}CuO_{4} finding that charge-density wave effects persist up to a remarkably high doping level of x=0.21 before disappearing at x=0.25. The inelastic excitation spectra remain essentially unchanged with doping despite crossing a topological transition in the Fermi surface. This indicates that the spectra contain little or no direct coupling to electronic excitations near the Fermi surface, rather they are dominated by the resonant cross section for phonons and charge-density-wave-induced phonon softening. We interpret our results in terms of a charge-density wave that is generated by strong correlations and a phonon response that is driven by the charge-density-wave-induced modification of the lattice.

Many-Body Physics of Single and Double Spin-Flip Excitations in NiO.

Understanding many-body physics of elementary excitations has advanced our control over material properties. Here, we study spin-flip excitations in NiO using Ni L_{3}-edge resonant inelastic x-ray scattering (RIXS) and present a strikingly different resonant energy behavior between single and double spin-flip excitations. Comparing our results with single-site full-multiplet ligand field theory calculations we find that the spectral weight of the double-magnon excitations originates primarily from the double spin-flip transition of the quadrupolar RIXS process within a single magnetic site. Quadrupolar spin-flip processes are among the least studied excitations, despite being important for multiferroic or spin-nematic materials due to their difficult detection. We identify intermediate state multiplets and intra-atomic core-valence exchange interactions as the key many-body factors determining the fate of such excitations. RIXS resonant energy dependence can act as a convincing proof of existence of nondipolar higher-ranked magnetic orders in systems for which, only theoretical predictions are available.

Detection of Acoustic Plasmons in Hole-Doped Lanthanum and Bismuth Cuprate Superconductors Using Resonant Inelastic X-Ray Scattering.

High T_{c} superconductors show a rich variety of phases associated with their charge degrees of freedom. Valence charges can give rise to charge ordering or acoustic plasmons in these layered cuprate superconductors. While charge ordering has been observed for both hole- and electron-doped cuprates, acoustic plasmons have only been found in electron-doped materials. Here, we use resonant inelastic x-ray scattering to observe the presence of acoustic plasmons in two families of hole-doped cuprate superconductors (La_{1.84}Sr_{0.16}CuO_{4} and Bi_{2}Sr_{1.6}La_{0.4}CuO_{6+δ}), crucially completing the picture. Interestingly, in contrast to the quasistatic charge ordering which manifests at both Cu and O sites, the observed acoustic plasmons are predominantly associated with the O sites, revealing a unique dichotomy in the behavior of valence charges in hole-doped cuprates.

Adductor canal versus femoral triangle anatomical locations for continuous catheter analgesia after total knee arthroplasty: a multicentre randomised controlled study.

BACKGROUND: Adductor canal (AC) catheters are being used to provide continuous postoperative analgesia after total knee arthroplasty (TKA) surgery. There are anatomical arguments that most AC catheters are being inserted into the femoral triangle (FT) compartment of the thigh rather than the AC compartment. The clinical relevance of this is unknown with respect to motor weakness, quality of analgesia, and opioid consumption. We hypothesised that AC catheters provide superior functional mobilisation on postoperative Day 1 after TKA as measured using the Timed Up and Go (TUG) test. METHODS: In this multinational, multicentre, double-blinded RCT, catheters were inserted under ultrasound guidance into the anatomical AC and FT compartments. The standardised protocol included spinal anaesthesia without intrathecal morphine, fixed catheter infusion rates, and oral analgesia. RESULTS: Of 151 subjects recruited, 75 were in the AC group and 76 in the FT group. There was no statistically significant difference in TUG on postoperative Day 1 between AC (38 [29-55] s) and FT subjects (44 [32-64] s) (median [inter-quartile range]); P=0.11). There was no difference in TUG Day 2, AC (38 [27-53] s) vs FT (42 [31-59] s); P=0.66. There were no statistically significant differences for secondary endpoints of pain level, effectiveness of pain relief, interference of functional activities and interpersonal relationships by pain, and opioid consumption between groups. CONCLUSIONS: There were no differences in immediate postoperative functional mobility, analgesia, and opioid consumption provided by catheters inserted into the AC vs FT locations for TKA surgery. CLINICAL TRIAL REGISTRATION: ANZCTR12617001421325.

Cognitive-Behavioral Therapy for Insomnia to Reduce Chronic Migraine: A Sequential Bayesian Analysis.

BACKGROUND: Insomnia is frequently comorbid with chronic migraine, and small trials suggest that cognitive-behavioral treatment of insomnia (CBTi) may reduce migraine frequency. This study endeavored to provide a quantitative synthesis of existing CBTi trials for adults with chronic migraine using Bayesian statistical methods, given their utility in combining prior knowledge with sequentially gathered data. METHODS: Completer analyses of 2 randomized trials comparing CBTi to a sham control intervention (Calhoun and Ford, 2007; Smitherman et al, 2016) were used to quantify the effects of a brief course of treatment on headache frequency. Change in headache frequency from baseline to the primary endpoint (6-8 weeks posttreatment) was regressed on group status using a Gaussian linear model with each study specified in the order of completion. To estimate the combined effect, posterior distributions from the Calhoun and Ford study were used as informative priors for conditioning on the Smitherman et al data. RESULTS: In a combined analysis of these prior studies, monthly headache frequency of the treatment group decreased by 6.2 days (95%CrI: -9.7 to -2.7) more than the control group, supporting an interpretation that there is a 97.5% chance that the treatment intervention is at least 2.7 days better than the control intervention. The analysis supports the hypothesis that at least for those who complete treatment, there is high probability that individuals who receive CBTi experience greater headache reduction than those who receive a control intervention equated for therapist time and out-of-session skills practice. CONCLUSION: Cognitive-behavioral interventions for comorbid insomnia hold promise for reducing headache frequency among those with chronic migraine. These findings add to a small but growing body of literature that migraineurs with comorbid conditions often respond well to behavioral interventions, and that targeting comorbidities may improve migraine itself.

The effect of deep muscle relaxation on the force required during Latissimus Dorsi dissection for breast reconstructive surgery: results of a prospective, double-blinded observational pilot study.

BACKGROUND: The use of neuromuscular blocking agents has previously been suggested to facilitate the dissection of the latissimus dorsi muscle during breast reconstructive surgery. The aim of this study was to quantify the influence of deep muscle relaxation on the force required to lift the latissimus dorsi muscle during flap preparation. METHODS: After ethics approval and written informed consent 15 patients scheduled for elective breast reconstruction with a latissimus dorsi pedicled flap (muscle flap, not myocutaneous flap) under general anaesthesia were prospectively included. Midway through the muscle dissection a sterile cotton tape was slung around the mid portion of the muscle and connected with a sterile strain gauge stably positioned just above the patient. Thereafter, the muscle was lifted by moving the strain gauge vertically upwards until a muscle tension similar to that created manually during muscle dissection was achieved. The force (N) and distance required to tension the muscle were recorded and the tension released. In a randomized and blinded crossover design either rocuronium (0.6 mg.kg-1) or normal saline were given intravenously, and the tension protocol was repeated 2 min after each drug administration. RESULTS: Muscle relaxation significantly reduced the force for flap tensioning (median [percentiles] - 22 [-32/-13] %; P = 0.011) in 10/15 patients. However, in the remaining 5 patients no significant effect was measured. Normal saline had no effect on the measured force. CONCLUSIONS: Deep muscle relaxation significantly reduces the force required to manually elevate the latissimus dorsi muscle during its dissection in the majority of but not all patients. TRIAL REGISTRATION: The study was retrospectively registered on [17.6.2014] with the Australian and New Zealand Clinical Trials Registry. ACTRN12614000637640.

Randomized Controlled Pilot Trial of Behavioral Insomnia Treatment for Chronic Migraine With Comorbid Insomnia.

BACKGROUND: Migraine frequently co-occurs with and is triggered by sleep disturbance, particularly insomnia, and the large majority of patients with chronic migraine (CM) have comorbid insomnia. Limited evidence suggests that behavioral regulation of sleep may reduce migraine frequency, but studies to date have not assessed the viability of stimulus control and sleep restriction interventions or included objective measurement of sleep parameters. The aim of this study, thus, was to pilot-test the efficacy of a brief behavioral insomnia intervention for adults with CM and comorbid insomnia; headache diaries and actigraphy were included to assess outcomes throughout the trial. METHODS: This randomized parallel-arm pilot trial recruited adults with both CM and comorbid insomnia. Participants were randomly assigned to three 30-minute biweekly sessions of cognitive-behavioral therapy for insomnia (CBTi) or control treatment. Participants were blinded to treatment and control conditions to control for outcome expectations. Each treatment condition involved training in and daily practice in 5 instructions/skills. The CBTi group learned and practiced skills pertaining to stimulus control and sleep restriction. The control intervention was the same as used by Calhoun and Ford (2007) and involved training in and daily practice of skills pertaining to keeping a consistent food/liquid intake, range of motion exercises, and acupressure. Participants provided outcome data via daily headache diaries, actigraphy, and self-report measures. The primary outcome was reduction in headache frequency at 2 weeks post-treatment and 6-week follow-up; secondary outcomes included other headache parameters, objective actigraphic and subjective changes in sleep, and treatment effect sizes and perceived credibility. Generalized estimating equations with a binomial logit link and inverse probability weights were used to assess the primary outcome among the intent-to-treat sample, and repeated measures generalized linear models were used to assess changes in secondary outcomes after controlling for baseline values. RESULTS: The intent-to-treat analyses included 31 adults (M age = 30.8 [12.9] years; 90.3% female; 80.6% white) with CM and comorbid insomnia. Both interventions yielded reductions in headache frequency at post-treatment (26.9% reduction for CBTi vs. 36.2% for control) and follow-up (48.9% for CBTi vs. 25.0% for control). At follow-up the odds of experiencing headache were 60% lower for CBTi than for control treatment, indicative of a large effect size that did not reach statistical significance after Bonferroni correction for assessing two primary endpoints (odds ratio: 0.40; 95% CI: 0.17, 0.91; P = .028). CBTi produced significantly larger increases than control treatment in total sleep time and sleep efficiency as quantified by actigraphy, as well as in self-reported insomnia severity. Adherence was high and treatments were perceived as credible without differences between groups, but the control group experienced a higher rate of dropouts. No adverse events were reported. CONCLUSIONS: Behavioral treatment of comorbid insomnia in individuals with CM produced large reductions in headache frequency, though some improvement in headache occurred with a behavioral intervention not focused on modifying sleep. Among the CBTi group only, both headache frequency and sleep parameters continued to improve after treatment, suggesting the presence of enduring effects over time. Directly treating insomnia using components of stimulus control and sleep restriction holds promise for reducing comorbid migraine. Development of and comparison to a truly inert pseudotherapy control presents unique challenges that future studies should address.

Development and Validation of a Four-Item Migraine Screening Algorithm Among a Nonclinical Sample: The Migraine-4.

OBJECTIVES: The present study sought to develop and validate a screening algorithm from the ICHD-3 beta diagnostic criteria for migraine utilizing a nonclinical sample. The goal was to determine the most sensitive and specific symptoms for differentiating migraine from other headache disorders and to validate the derived symptom algorithm as a screening measure. BACKGROUND: Despite its prevalence and impact, migraine remains under-recognized and under-treated. The U.S. Headache Consortium recommended development and dissemination of validated screening measures as a means to improve diagnosis. METHODS: Participants were 1829 young adults (71.5% female; 74.4% white; mean age = 19.09 years [SD = 2.05]) who reported headache via computerized diagnostic interview. From this group, 158 were found to have ICHD episodic or chronic migraine and were randomly split into experimental and holdout validation samples. Within the experimental sample, receiver operating characteristic (ROC) curve data were obtained for each candidate symptom (item); backward stepwise logistic regression analysis was performed among the items with the most predictive likelihood ratios to determine the optimal model for differentiating migraine from non-migrainous headache. The retained four-symptom algorithm was then validated among the holdout sample, in which various cutoff points were compared to gold standard diagnosis via ROC curve estimations to determine the optimal operating point (OOP) of the algorithm as a screening measure. RESULTS: Attack duration of 4-72 hours (100% [95% CI = 95-100%]), severity ≥ 5 (91% [82-97%]), photophobia (90% [80-96%]), and phonophobia (90% [80-96%]) showed the highest sensitivity, while vomiting (98% [96-99%]), duration of 4-72 hours (92% [90-94%]), nausea (89% [86-91%]), and headache-related disability (88% [85-91%]) showed the highest specificity. The optimal retained model (Migraine-4) included: duration of 4-72 hours, nausea, photophobia, and phonophobia. Among the holdout validation sample, the OOP was positive endorsement of three out of four symptoms, which had a sensitivity of 94% (95% CI = 87-98%), a specificity of 92% (90-94%), and an area under the curve of 93% (90-96%; +LR = 12.37, -LR = 0.06, PPV = 67%, NPV = 99%). CONCLUSIONS: The optimal model shares some similarities with previous models but performed better than prior screeners at differentiating migraine from other headache presentations. The Migraine-4 has utility in identifying migraine among nonclinical and young adult samples. Further research with this measure is warranted to determine its utility with treatment-seeking patients and validity in direct comparison to established screening instruments.

Density of river otters (Lontra canadensis) in relation to energy development in the Green River Basin, Wyoming.

Exploration and extraction of oil and natural gas have increased in recent years and are expected to expand in the future. Reduction in water quality from energy extraction may negatively affect water supply for agriculture and urban use within catchments as well as down river. We used non-invasive genetic techniques and capture-recapture modeling to estimate the abundance and density of North American river otters (Lontra canadensis), a sentinel species of aquatic ecosystems, in Southwestern Wyoming. While densities in two of three river reaches were similar to those reported in other freshwater systems in the western US (1.45-2.39 km per otter), otters appeared to avoid areas near energy development. We found no strong difference in habitat variables, such as overstory cover, at the site or reach level. Also, fish abundance was similar among the three river reaches. Otter activity in our study area could have been affected by elevated levels of disturbance surrounding the industrial gas fields, and by potential surface water contamination as indicated by patterns in water conductivity. Continued monitoring of surface water quality in Southwestern Wyoming with the aid of continuously recording devices and sentinel species is warranted.

Absence of superconductivity in fluorine-doped neptunium pnictide NpFeAsO.

X-ray diffraction, specific heat, magnetic susceptibility and inelastic x-ray scattering measurements on the transurarium oxypnictides NpFeAsO and NpFeAsO0.85F0.15 are presented. No superconductivity down to 2 K was observed upon fluorine doping, contrary to the structurally analogous rare-earth pnictides. No modification of the phonon density of states was observed upon doping with fluorine. We discuss our results in light of the latest experimental and theoretical studies on the role of phonons in the superconducting pnictide compounds.

Metabolic regulation in model ascomycetes--adjusting similar genomes to different lifestyles.

The related yeasts Saccharomyces cerevisiae and Candida albicans have similar genomes but very different lifestyles. These fungi have modified transcriptional and post-translational regulatory processes to adapt their similar genomes to the distinct biological requirements of the two yeasts. We review recent findings comparing the differences between these species, highlighting how they have achieved specialized metabolic capacities tailored to their lifestyles despite sharing similar genomes. Studying this transcriptional and post-transcriptional rewiring may improve our ability to interpret phenotype from genotype.

Anxiety sensitivity and headache: diagnostic differences, impact, and relations with perceived headache triggers.

BACKGROUND: Anxiety sensitivity (AS), the fear of arousal-related bodily sensations due to beliefs about presumed harmful consequences, predicts fear and avoidance among musculoskeletal pain patients but remains largely unexplored in headache. The aims of this cross-sectional study were to evaluate AS among young adult migraine and tension-type headache sufferers and to assess relations with headache impact and perceived susceptibility to headache triggers. METHODS: A total of 2350 young adults (72.6% with primary headache; 64.9% female; 22.5% minority) completed measures of AS and headache symptomatology. Generalized linear models assessed relations between AS and ICHD-II diagnosis, headache-related disability, and perceived trigger susceptibility. Canonical correlation analyses quantified relations with headache symptomatology. RESULTS: AS reliably differentiated headache sufferers from those without headache, being highest among chronic migraineurs and episodic migraineurs with aura. AS accounted for 8.4% of variance in headache symptomatology and was most strongly associated with prototypical migraine symptoms. AS predicted headache-related disability and trigger variables, even after controlling for headache frequency and severity. AS accounted for more unique variance in disability than depression and anxiety symptoms combined. CONCLUSIONS: AS predicts pain itself, adjustment to pain, and evaluation of factors influencing pain among primary headache sufferers, even after controlling for headache burden. Further study of AS among headache patients is warranted.

Competing exchange interactions on the verge of a metal-insulator transition in the two-dimensional spiral magnet Sr3Fe2O7.

We report a neutron scattering study of the magnetic order and dynamics of the bilayer perovskite Sr(3)Fe(2)O(7), which exhibits a temperature-driven metal-insulator transition at 340 K. We show that the Fe(4+) moments adopt incommensurate spiral order below T(N) = 115 K and provide a comprehensive description of the corresponding spin-wave excitations. The observed magnetic order and excitation spectra can be well understood in terms of an effective spin Hamiltonian with interactions ranging up to third-nearest-neighbor pairs. The results indicate that the helical magnetism in Sr(3)Fe(2)O(7) results from competition between ferromagnetic double-exchange and antiferromagnetic superexchange interactions whose strengths become comparable near the metal-insulator transition. They thus confirm a decades-old theoretical prediction and provide a firm experimental basis for models of magnetic correlations in strongly correlated metals.