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Interneuron NMDA Receptor Ablation Induces Hippocampus-Prefrontal Cortex Functional Hypoconnectivity after Adolescence in a Mouse Model of Schizophrenia

Although the etiology of schizophrenia is still unknown, it is accepted to be a neurodevelopmental disorder that results from the interaction of genetic vulnerabilities and environmental insults. Although schizophrenia's pathophysiology is still unclear, postmortem studies point toward a dysfunction of cortical interneurons as a central element. It has been suggested that alterations in parvalbumin-positive interneurons in schizophrenia are the consequence of a deficient signaling through NMDARs. Animal studies demonstrated that early postnatal ablation of the NMDAR in corticolimbic interneurons induces neurobiochemical, physiological, behavioral, and epidemiological phenotypes related to schizophrenia. Notably, the behavioral abnormalities emerge only after animals complete their maturation during adolescence and are absent if the NMDAR is deleted during adulthood. This suggests that interneuron dysfunction must interact with development to impact on behavior. Here, we assess in vivo how an early NMDAR ablation in corticolimbic interneurons impacts on mPFC and ventral hippocampus functional connectivity before and after adolescence. In juvenile male mice, NMDAR ablation results in several pathophysiological traits, including increased cortical activity and decreased entrainment to local gamma and distal hippocampal theta rhythms. In addition, adult male KO mice showed reduced ventral hippocampus-mPFC-evoked potentials and an augmented low-frequency stimulation LTD of the pathway, suggesting that there is a functional disconnection between both structures in adult KO mice. Our results demonstrate that early genetic abnormalities in interneurons can interact with postnatal development during adolescence, triggering pathophysiological mechanisms related to schizophrenia that exceed those caused by NMDAR interneuron hypofunction alone.

SIGNIFICANCE STATEMENT NMDAR hypofunction in cortical interneurons has been linked to schizophrenia pathophysiology. How a dysfunction of GABAergic cortical interneurons interacts with maturation during adolescence has not been clarified yet. Here, we demonstrate in vivo that early postnatal ablation of the NMDAR in corticolimbic interneurons results in an overactive but desynchronized PFC before adolescence. Final postnatal maturation during this stage outspreads the impact of the genetic manipulation toward a functional disconnection of the ventral hippocampal-prefrontal pathway, probably as a consequence of an exacerbated propensity toward hippocampal-evoked depotentiation plasticity. Our results demonstrate a complex interaction between genetic and developmental factors affecting cortical interneurons and PFC function.




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The Effect of Counterfactual Information on Outcome Value Coding in Medial Prefrontal and Cingulate Cortex: From an Absolute to a Relative Neural Code

Adaptive coding of stimuli is well documented in perception, where it supports efficient encoding over a broad range of possible percepts. Recently, a similar neural mechanism has been reported also in value-based decision, where it allows optimal encoding of vast ranges of values in PFC: neuronal response to value depends on the choice context (relative coding), rather than being invariant across contexts (absolute coding). Additionally, value learning is sensitive to the amount of feedback information: providing complete feedback (both obtained and forgone outcomes) instead of partial feedback (only obtained outcome) improves learning. However, it is unclear whether relative coding occurs in all PFC regions and how it is affected by feedback information. We systematically investigated univariate and multivariate feedback encoding in various mPFC regions and compared three modes of neural coding: absolute, partially-adaptive and fully-adaptive.

Twenty-eight human participants (both sexes) performed a learning task while undergoing fMRI scanning. On each trial, they chose between two symbols associated with a certain outcome. Then, the decision outcome was revealed. Notably, in one-half of the trials participants received partial feedback, whereas in the other half they got complete feedback. We used univariate and multivariate analysis to explore value encoding in different feedback conditions.

We found that both obtained and forgone outcomes were encoded in mPFC, but with opposite sign in its ventral and dorsal subdivisions. Moreover, we showed that increasing feedback information induced a switch from absolute to relative coding. Our results suggest that complete feedback information enhances context-dependent outcome encoding.

SIGNIFICANCE STATEMENT This study offers a systematic investigation of the effect of the amount of feedback information (partial vs complete) on univariate and multivariate outcome value encoding, within multiple regions in mPFC and cingulate cortex that are critical for value-based decisions and behavioral adaptation. Moreover, we provide the first comparison of three possible models of neural coding (i.e., absolute, partially-adaptive, and fully-adaptive coding) of value signal in these regions, by using commensurable measures of prediction accuracy. Taken together, our results help build a more comprehensive picture of how the human brain encodes and processes outcome value. In particular, our results suggest that simultaneous presentation of obtained and foregone outcomes promotes relative value representation.




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Striatal Nurr1 Facilitates the Dyskinetic State and Exacerbates Levodopa-Induced Dyskinesia in a Rat Model of Parkinson's Disease

The transcription factor Nurr1 has been identified to be ectopically induced in the striatum of rodents expressing l-DOPA-induced dyskinesia (LID). In the present study, we sought to characterize Nurr1 as a causative factor in LID expression. We used rAAV2/5 to overexpress Nurr1 or GFP in the parkinsonian striatum of LID-resistant Lewis or LID-prone Fischer-344 (F344) male rats. In a second cohort, rats received the Nurr1 agonist amodiaquine (AQ) together with l-DOPA or ropinirole. All rats received a chronic DA agonist and were evaluated for LID severity. Finally, we performed single-unit recordings and dendritic spine analyses on striatal medium spiny neurons (MSNs) in drug-naïve rAAV-injected male parkinsonian rats. rAAV-GFP injected LID-resistant hemi-parkinsonian Lewis rats displayed mild LID and no induction of striatal Nurr1 despite receiving a high dose of l-DOPA. However, Lewis rats overexpressing Nurr1 developed severe LID. Nurr1 agonism with AQ exacerbated LID in F344 rats. We additionally determined that in l-DOPA-naïve rats striatal rAAV-Nurr1 overexpression (1) increased cortically-evoked firing in a subpopulation of identified striatonigral MSNs, and (2) altered spine density and thin-spine morphology on striatal MSNs; both phenomena mimicking changes seen in dyskinetic rats. Finally, we provide postmortem evidence of Nurr1 expression in striatal neurons of l-DOPA-treated PD patients. Our data demonstrate that ectopic induction of striatal Nurr1 is capable of inducing LID behavior and associated neuropathology, even in resistant subjects. These data support a direct role of Nurr1 in aberrant neuronal plasticity and LID induction, providing a potential novel target for therapeutic development.

SIGNIFICANCE STATEMENT The transcription factor Nurr1 is ectopically induced in striatal neurons of rats exhibiting levodopa-induced dyskinesia [LID; a side-effect to dopamine replacement strategies in Parkinson's disease (PD)]. Here we asked whether Nurr1 is causing LID. Indeed, rAAV-mediated expression of Nurr1 in striatal neurons was sufficient to overcome LID-resistance, and Nurr1 agonism exacerbated LID severity in dyskinetic rats. Moreover, we found that expression of Nurr1 in l-DOPA naïve hemi-parkinsonian rats resulted in the formation of morphologic and electrophysiological signatures of maladaptive neuronal plasticity; a phenomenon associated with LID. Finally, we determined that ectopic Nurr1 expression can be found in the putamen of l-DOPA-treated PD patients. These data suggest that striatal Nurr1 is an important mediator of the formation of LID.




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The Firing of Theta State-Related Septal Cholinergic Neurons Disrupt Hippocampal Ripple Oscillations via Muscarinic Receptors

The septo-hippocampal cholinergic system is critical for hippocampal learning and memory. However, a quantitative description of the in vivo firing patterns and physiological function of medial septal (MS) cholinergic neurons is still missing. In this study, we combined optogenetics with multichannel in vivo recording and recorded MS cholinergic neuron firings in freely behaving male mice for 5.5–72 h. We found that their firing activities were highly correlated with hippocampal theta states. MS cholinergic neurons were highly active during theta-dominant epochs, such as active exploration and rapid eye movement sleep, but almost silent during non-theta epochs, such as slow-wave sleep (SWS). Interestingly, optogenetic activation of these MS cholinergic neurons during SWS suppressed CA1 ripple oscillations. This suppression could be rescued by muscarinic M2 or M4 receptor antagonists. These results suggest the following important physiological function of MS cholinergic neurons: maintaining high hippocampal acetylcholine level by persistent firing during theta epochs, consequently suppressing ripples and allowing theta oscillations to dominate.

SIGNIFICANCE STATEMENT The major source of acetylcholine in the hippocampus comes from the medial septum. Early experiments found that lesions to the MS result in the disappearance of hippocampal theta oscillation, which leads to speculation that the septo-hippocampal cholinergic projection contributing to theta oscillation. In this article, by long-term recording of MS cholinergic neurons, we found that they show a theta state-related firing pattern. However, optogenetically activating these neurons shows little effect on theta rhythm in the hippocampus. Instead, we found that activating MS cholinergic neurons during slow-wave sleep could suppress hippocampal ripple oscillations. This suppression is mediated by muscarinic M2 and M4 receptors.




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Ependymal Vps35 Promotes Ependymal Cell Differentiation and Survival, Suppresses Microglial Activation, and Prevents Neonatal Hydrocephalus

Hydrocephalus is a pathologic condition associated with various brain diseases, including Alzheimer's disease (AD). Dysfunctional ependymal cells (EpCs) are believed to contribute to the development of hydrocephalus. It is thus of interest to investigate EpCs' development and function. Here, we report that vacuolar protein sorting-associated protein 35 (VPS35) is critical for EpC differentiation, ciliogenesis, and survival, and thus preventing neonatal hydrocephalus. VPS35 is abundantly expressed in EpCs. Mice with conditional knock-out (cKO) of Vps35 in embryonic (Vps35GFAP-Cre and Vps35Emx1-Cre) or postnatal (Vps35Foxj1-CreER) EpC progenitors exhibit enlarged lateral ventricles (LVs) and hydrocephalus-like pathology. Further studies reveal marked reductions in EpCs and their cilia in both Vps35GFAP-Cre and Vps35Foxj1-CreER mutant mice. The reduced EpCs appear to be due to impairments in EpC differentiation and survival. Additionally, both Vps35GFAP-Cre and Vps35Foxj1-CreER neonatal pups exhibit increased cell proliferation and death largely in a region close to LV-EpCs. Many microglia close to the mutant LV-EpC region become activated. Depletion of the microglia by PLX3397, an antagonist of colony-stimulating factor 1 receptor (CSF1R), restores LV-EpCs and diminishes the pathology of neonatal hydrocephalus in Vps35Foxj1-CreER mice. Taken together, these observations suggest unrecognized functions of Vps35 in EpC differentiation, ciliogenesis, and survival in neonatal LV, and reveal pathologic roles of locally activated microglia in EpC homeostasis and hydrocephalus development.

SIGNIFICANCE STATEMENT This study reports critical functions of vacuolar protein sorting-associated protein 35 (VPS35) not only in promoting ependymal cell (EpC) differentiation, ciliogenesis, and survival, but also in preventing local microglial activation. The dysfunctional EpCs and activated microglia are likely to induce hydrocephalus.




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Neonatal Stroke and TLR1/2 Ligand Recruit Myeloid Cells through the Choroid Plexus in a CX3CR1-CCR2- and Context-Specific Manner

Neonatal stroke is as frequent as stroke in the elderly, but many pathophysiological injury aspects are distinct in neonates, including immune signaling. While myeloid cells can traffic into the brain via multiple routes, the choroid plexus (CP) has been identified as a uniquely educated gate for immune cell traffic during health and disease. To understand the mechanisms of myeloid cell trafficking via the CP and their influence on neonatal stroke, we characterized the phenotypes of CP-infiltrating myeloid cells after transient middle cerebral artery occlusion (tMCAO) in neonatal mice of both sexes in relation to blood-brain barrier permeability, injury, microglial activation, and CX3CR1-CCR2 signaling, focusing on the dynamics early after reperfusion. We demonstrate rapid recruitment of multiple myeloid phenotypes in the CP ipsilateral to the injury, including inflammatory CD45+CD11b+Ly6chighCD86+, beneficial CD45+CD11b+Ly6clowCD206+, and CD45+CD11b+Ly6clowLy6ghigh cells, but only minor leukocyte infiltration into acutely ischemic-reperfused cortex and negligible vascular albumin leakage. We report that CX3CR1-CCR2-mediated myeloid cell recruitment contributes to stroke injury. Considering the complexity of inflammatory cascades triggered by stroke and a role for TLR2 in injury, we also used direct TLR2 stimulation as an independent injury model. TLR2 agonist rapidly recruited myeloid cells to the CP, increased leukocytosis in the CSF and blood, but infiltration into the cortex remained low over time. While the magnitude and the phenotypes of myeloid cells diverged between tMCAO and TLR2 stimulation, in both models, disruption of CX3CR1-CCR2 signaling attenuated both monocyte and neutrophil trafficking to the CP and cortex.

SIGNIFICANCE STATEMENT Stroke during the neonatal period leads to long-term disabilities. The mechanisms of ischemic injury and inflammatory response differ greatly between the immature and adult brain. We examined leukocyte trafficking via the choroid plexus (CP) following neonatal stroke in relation to blood-brain barrier integrity, injury, microglial activation, and signaling via CX3CR1 and CCR2 receptors, or following direct TLR2 stimulation. Ischemia-reperfusion triggered marked unilateral CX3CR1-CCR2 dependent accumulation of diverse leukocyte subpopulations in the CP without inducing extravascular albumin leakage or major leukocyte infiltration into the brain. Disrupted CX3CR1-CCR2 signaling was neuroprotective in part by attenuating monocyte and neutrophil trafficking. Understanding the migratory patterns of CP-infiltrating myeloid cells with intact and disrupted CX3CR1-CCR2 signaling could identify novel therapeutic targets to protect the neonatal brain.




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It's about time we talk about soil!

There can be no life without it, it feeds us and we are responsible for it! Soil is formed from rocks that are decomposed slowly by sun, the wind and the rain, by animals and plants. But it is in danger because of expanding cities, deforestation, unsustainable land use and management practices, pollution, overgrazing and climate change. The current rate [...]




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Milk Talk – The role of milk and dairy products in human nutrition

As part of a balanced diet, milk and dairy products can be an important source of dietary energy, protein and fat. But, the scientific evidence is massing up that regular consumption of large quantities of milk can be bad for your health, and campaigners are making noise about the environmental and international costs of large-scale intensive dairy farming. We put together [...]




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On ecosystems and the services they provide – Let's talk facts

Ecosystem services make human life possible by, for example, providing nutritious food and clean water, regulating disease and climate, supporting the pollination of crops and soil formation, and providing recreational, cultural and spiritual benefits. In 2014, the value of ecosystem services was estimated at a staggering US$ 125 trillion.  Ecosystem services, provided by biodiversity, are fundamental to food production and [...]




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Digital innovations are bringing youth back to agriculture

Youth around the world are increasingly turning away from agriculture. Traditionally requiring tough manual labour and offering low wages, agriculture does not often appeal to new generations who generally prefer to try their luck finding jobs in cities.  




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Special meeting Monday: Council to talk port proposals




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Council to mull hospital lease: Scrutinizes Metlakatla power tie-in




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Council talks grant funding: Requests extension for public comment period on Metlakatla power tie-in




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Art Is Dead The Dowser Married the Alchemist - Install Shots




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Catalist (Israel)




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Community-Researcher Collaboration Reveals Ancient Maya Capital in Backyard

A recent excavation located the first physical evidence of the capital of the Maya kingdom of Sak Tz'i', founded in 750 B.C.




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Watch Seven Medieval Castles' Digital Reconstruction

Architects and designers restored royal ruins across Europe to their former glory




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Digital Reconstructions Reveal 200-Million-Year-Old Dinosaur Embryo’s Unusual Teeth

New scans suggest unhatched dinosaurs reabsorbed a set of teeth during development




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England to Debut World's Longest Coastal Path by Middle of Next Year

The nearly 2,800-mile-long walking route runs all the way around the English coast




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Nostalgic for the North? Take a Virtual Dogsled Ride in Fairbanks, Alaska

Armchair travelers can also enjoy 360-degree views of the city's famed Northern Lights




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Deep-Sea Mining’s Environmental Toll Could Last Decades

A study of microbial communities at the site of a 1989 deep-sea mining test suggests the fragile ecosystem may take half a century to fully recover




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Monumental: In Search of America's National Treasure




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Recall opponents seek to drop court fight: Stand Tall With Mike withdraws its appeal, gearing up for possible recall election




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How COVID-19 Could Inform the Future of Hospital Design

Modified hospital designs have become necessary as the first wave of the pandemic tears through U.S. communities




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Play the Smithsonian Magazine Weekly Word Search: State Capitals

Find the capital cities, working from a list of state names




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Vitality

vitality




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Window Installer Working on a New Building

Man working on a new building




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No magic bullet: Former head of AIDS Thunder Bay talks about similarities between HIV, COVID-19

A virus that spreads fear and stigma, as well as disease. It’s the story of HIV/AIDS as well as COVID-19. The former executive director of AIDS Thunder Bay reflects on the similarities he sees between HIV 35 years ago, and the coronavirus now.



  • News/Canada/Thunder Bay

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Exploring local community is 'first key' to saving hospitality industry, says Thunder Bay Tourism manager

The tourism and hospitality industries, which play a large role in the economy of almost every community in northwestern Ontario, are taking a beating during the COVID-19 pandemic. Now, the manager of Tourism Thunder Bay is figuring out how “dire” the situation is, and what could be done to help.



  • News/Canada/Thunder Bay

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Suspect in custody after firearm incident Thursday at Rainy River hospital, OPP say

Provincial Police have a suspect in custody after a firearms incident Thursday morning at the hospital in the small northwestern Ontario community of Rainy River.



  • News/Canada/Thunder Bay

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Six hours after delivery, and then go for maternal support person at Thunder Bay hospital

Parents-to-be who will have their new child delivered at the Thunder Bay Regional Health Sciences Centre have to follow a different set of guidelines than found at many other hospitals across Ontario.



  • News/Canada/Thunder Bay

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Dental system 'nightmare' leaves man with month-long toothache

64-year-old John Neville, in agony and needing his wisdom tooth extracted, has been navigating a complex tangle of COVID-19 restrictions in an unsuccessful attempt at getting emergency dental care.



  • News/Canada/Nfld. & Labrador

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Staining the Blot for Total Protein with Ponceau S

Before probing blots for the presence of an antigen, the total composition of the transferred proteins can be determined by staining the nitrocellulose or polyvinylidene fluoride (PVDF) membrane. Staining for proteins is useful to determine the position of the non-prestained molecular weight markers or individual lanes on the gel and to ensure that efficient transfer has occurred. It can be also used to verify equal loading of the samples in the gel when a comparison of the protein of interest between the different samples is important. The conventional procedures such as Coomassie Blue and silver staining methods used for staining polyacrylamide gels are incompatible with immunoblotting. Ponceau S is the more common staining method in immunoblotting protocols because it is compatible with antibody–antigen binding, is cost efficient, and provides a good contrast between the stained bands and background. In this protocol, nitrocellulose or PVDF membrane is rinsed with ultrapure H2O after the transfer of proteins. Ponceau S dye is applied as an acidic aqueous solution, and the proteins on the membrane are stained with red color. The membrane is briefly destained with water and can be photographed or scanned to obtain the image of the total protein staining. Individual lane positions or the molecular weight standards can be marked with a pencil, if required.




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Volatility spillovers and capital buffers among the G-SIBs

We assess the dynamics of volatility spillovers among global systemically important banks (G-SIBs). We measure spillovers using vector-autoregressive models of range volatility of the equity prices of G-SIBs, together with machine learning methods. We then compare the size of these spillovers with the degree of systemic importance measured by the Basel Committee on Banking Supervision's G-SIB bucket designations.




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Innovation in a crisis Q&A series: Nightingale Hospitals




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CPMI report sets out considerations for developers of wholesale digital tokens

Press release: CPMI report sets out considerations for developers of wholesale digital tokens, 12 December 2019




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Central bank group to assess potential cases for central bank digital currencies

The Bank of Canada, the Bank of England, the Bank of Japan, the European Central Bank, the Sveriges Riksbank and the Swiss National Bank, together with the Bank for International Settlements (BIS), have created a group to share experiences as they assess the potential case for central bank digital currency (CBDC) in their home jurisdictions. (Press release, 21 January 2020)




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Michigan Orders Flint Hospital To Reduce Legionnaires' Risks

Michigan officials are ordering a Flint hospital to take steps to reduce the risk of exposure to Legionella bacteria and Legionnaires' disease at the facility.




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Mental Health in the Age of the Coronavirus

The struggle between fear and comfort.




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Teen charged in fatal shooting at Gilmour Street Airbnb

Ottawa police have arrested a 15-year-old boy in connection with January's shooting. He's charged with first-degree murder and attempted murder.



  • News/Canada/Ottawa

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The urban boundary debate is vitally important, so should it happen online?

The upcoming debate about whether to expand the urban boundary is one of the city's big issues this term. But instead of delaying it, the city's testing out a never-before-attempted democratic process. Should they?



  • News/Canada/Ottawa

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Kurt Browning, figure skaters worldwide unite digitally to help healthcare workers

Despite having no ice on which to perform, more than 40 figure skaters from nine countries will take part in a fundraiser Friday to help health care workers on the front lines battling the new coronavirus.



  • Sports/Olympics/Winter Sports/Figure Skating

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December 10 Metals Commentary: Larry Shover

Larry Shover, SFG Alternatives




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December 11 Metals Commentary: Bob Iaccino

Bob Iaccino, Path Trading Partners




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December 12 Metals Commentary: Larry Shover

Larry Shover, SFG Alternatives




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December 13 Metals Commentary: Dan Deming

Dan Deming, KKM Financial




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December 13 Metals Commentary: Dan Deming

Dan Deming, KKM Financial




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December 17 Metals Commentary: Larry Shover

Larry Shover, SFG Alternatives




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December 18 Metals Commentary: Bob Iaccino

Bob Iaccino, Path Trading Partners




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December 19 Metals Commentary: Larry Shover

Larry Shover, SFG Alternatives