We investigate lead-lag relationships among monthly country stock returns and identify a leading role for the United States: lagged U.S. returns significantly predict returns in numerous non-U.S. ...industrialized countries, while lagged non-U.S. returns display limited predictive ability with respect to U.S. returns. We estimate a newsdiffusion model, and the results indicate that return shocks arising in the United States are only fully reflected in equity prices outside of the United States with a lag, consistent with a gradual information diffusion explanation of the predictive power of lagged U.S. returns.
Welch and Goyal (2008) find that numerous economic variables with in-sample predictive ability for the equity premium fail to deliver consistent out-of-sample forecasting gains relative to the ...historical average. Arguing that model uncertainty and instability seriously impair the forecasting ability of individual predictive regression models, we recommend combining individual forecasts. Combining delivers statistically and economically significant out-of-sample gains relative to the historical average consistently over time. We provide two empirical explanations for the benefits of forecast combination: (i) combining forecasts incorporates information from numerous economic variables while substantially reducing forecast volatility; (ii) combination forecasts are linked to the real economy.
Abstract Introduction Our objective was to assess the frequency of lipohypertrophy (LH) and its relationship to site rotation, needle reuse, glucose variability, hypoglycaemia and use of insulin. ...Methods The study included 430 outpatients injecting insulin who filled out a wide-ranging questionnaire regarding their injection technique. Then, a diabetes nurse examined their injection sites for the presence of LH. Results Nearly two-thirds (64.4%) of patients had LH. There was a strong relationship between the presence of LH and non-rotation of sites, with correct rotation technique having the strongest protective value against LH. Of the patients who correctly rotated sites, only 5% had LH while, of the patients with LH, 98% either did not rotate sites or rotated incorrectly. Also, 39.1% of patients with LH had unexplained hypoglycaemia and 49.1% had glycaemic variability compared with only 5.9% and 6.5%, respectively, in those without LH. LH was also related to needle reuse, with risk increasing significantly when needles were used > 5 times. Total daily insulin doses for patients with and without LH averaged 56 and 41 IU/day, respectively. This 15 IU difference equates to a total annual cost to the Spanish healthcare system of > €122 million. This was also the first study in which the use of ultrasound allowed the description of an “echo signature” for LH. Conclusion Correct injection site rotation appears to be the critical factor in preventing LH, which is associated with reduced glucose variability, hypoglycaemia, insulin consumption and costs.
Long intergenic noncoding RNAs (lincRNAs) are long noncoding transcripts (>200 nt) from the intergenic regions of annotated protein-coding genes. One of the most highly induced lincRNAs in ...macrophages upon TLR ligation is lincRNA-Cox2, which was recently shown to mediate the activation and repression of distinct classes of immune genes in innate immune cells. We report that lincRNA-Cox2, located at chromosome 1 proximal to the PG-endoperoxide synthase 2 (Ptgs2/Cox2) gene, is an early-primary inflammatory gene controlled by NF-κB signaling in murine macrophages. Functionally, lincRNA-Cox2 is required for the transcription of NF-κB-regulated late-primary inflammatory response genes stimulated by bacterial LPS. Specifically, lincRNA-Cox2 is assembled into the switch/sucrose nonfermentable (SWI/SNF) complex in cells after LPS stimulation. This resulting lincRNA-Cox2/SWI/SNF complex can modulate the assembly of NF-κB subunits to the SWI/SNF complex, and ultimately, SWI/SNF-associated chromatin remodeling and transactivation of the late-primary inflammatory-response genes in macrophages in response to microbial challenge. Therefore, our data indicate a new regulatory role for NF-κB-induced lincRNA-Cox2 as a coactivator of NF-κB for the transcription of late-primary response genes in innate immune cells through modulation of epigenetic chromatin remodeling.
The gastrointestinal epithelium guides the immune system to differentiate between commensal and pathogenic microbiota, which relies on intimate links with the type I IFN signal pathway. Epithelial ...cells along the epithelium provide the front line of host defense against pathogen infection in the gastrointestinal tract. Increasing evidence supports the regulatory potential of long noncoding RNAs (lncRNAs) in immune defense but their role in regulating intestinal epithelial antimicrobial responses is still unclear. Cryptosporidium, a protozoan parasite that infects intestinal epithelial cells, is an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children in developing countries. Recent advances in Cryptosporidium research have revealed a strong type I IFN response in infected intestinal epithelial cells. We previously identified a panel of host cell lncRNAs that are upregulated in murine intestinal epithelial cells following microbial challenge. One of these lncRNAs, NR_033736, is upregulated in intestinal epithelial cells following Cryptosporidium infection and displays a significant suppressive effect on type I IFN-controlled gene transcription in infected host cells. NR_033736 can be assembled into the ISGF3 complex and suppresses type I IFN-mediated gene transcription. Interestingly, upregulation of NR_033736 itself is triggered by the type I IFN signaling. Moreover, NR_033736 modulates epithelial anti-Cryptosporidium defense. Our data suggest that upregulation of NR_033736 provides negative feedback regulation of type I IFN signaling through suppression of type I IFN-controlled gene transcription, and consequently, contributing to fine-tuning of epithelial innate defense against microbial infection.
Humans form lasting memories of stimuli that were only encountered once. This naturally occurs when listening to a story, however it remains unclear how and when memories are stored and retrieved ...during story-listening. Here, we first confirm in behavioral experiments that participants can learn about the structure of a story after a single exposure and are able to recall upcoming words when the story is presented again. We then track mnemonic information in high frequency activity (70-200 Hz) as patients undergoing electrocorticographic recordings listen twice to the same story. We demonstrate predictive recall of upcoming information through neural responses in auditory processing regions. This neural measure correlates with behavioral measures of event segmentation and learning. Event boundaries are linked to information flow from cortex to hippocampus. When listening for a second time, information flow from hippocampus to cortex precedes moments of predictive recall. These results provide insight on a fine-grained temporal scale into how episodic memory encoding and retrieval work under naturalistic conditions.
As many as 6 – 8 million CT scans are performed annually in the United States on pediatric patients. The majority of these CT scans are not performed in pediatric hospitals that specialize in ...addressing the unique requirements of pediatric imaging. Instead, most of these scans occur in adult hospitals, where pediatric CT scanning is a small fraction of the total caseload. Both adult and pediatric hospitals need a simple method that allows the management of the CT radiation dose received by each patient based on the patient's physical size. This lecture suggests some simple tools and techniques that the qualified medical physicist can introduce to an individual practice in an effort to properly manage CT doses. This lecture begins by exploring the unique challenges presented by the pediatric patient in the management of their radiation dose during CT scanning. This is followed by an explanation of the basic science behind the development of the Size Specific Dose Estimate (SSDE) in CT, the strengths and weaknesses of the method, and some sample calculations. The presentation concludes by exploring the clinical application of SSDE in the day to day management of the radiation dose during CT scanning of not only small pediatric patients, but also patients who are larger than the average size adult.
Learning Objectives:
1. Understand the basic challenges associated with CT imaging of children.
2. Understand the basic science used to develop SSDE, its strengths and its limitations
3. Understand the application of SSDE in the clinic in the daily management of pediatric CT doses.
Abstract Aim Injections and fingersticks administered to patients with diabetes in health care settings present a risk of blood exposure to the injector as well as other workers in potential contact ...with sharps. Such exposures could lead to transmission of bloodborne pathogens such as hepatitis and HIV. A recent EU Directive requires that where such risks have been identified, processes and devices must be put in place to reduce or eliminate the risk. The aim of this paper is to provide formal guidelines on the application of this Directive to diabetes care settings. These evidence-based recommendations were written and vetted by a large group of international safety experts. Methods A systematic literature search was conducted for all peer-reviewed studies and publications which bear on sharps safety in diabetes. Initially a group of experts reviewed this literature and drafted the recommendations. These were then presented for review, debate and revision to 57 experts from 14 countries at the WISE workshop in October, 2011. After the WISE meeting, the revised Recommendations were circulated electronically to attendees on three occasions, each time in a new iteration with revisions. Results Each recommendation was graded by the weight it should have in daily practice and by its degree of support in the medical literature. The topics covered include Risks of Sharps Injury and Muco-cutaneous Exposure, The EU Directive, Device Implications, Injection Technique Implications, Education and Training (Creating a “Safety Culture”), Value, Awareness and Responsibility. Conclusion These safety recommendations provide practical guidance and fill an important gap in diabetes management. If followed, they should help ensure safe, effective and largely injury-free injections and fingersticks. They will serve as the roadmap for applying the new EU Directive to diabetes care.
We investigate the empirical relevance of structural breaks for GARCH models of exchange rate volatility using both in-sample and out-of-sample tests. We find significant evidence of structural ...breaks in the unconditional variance of seven of eight US dollar exchange rate return series over the 1980-2005 period-implying unstable GARCH processes for these exchange rates-and GARCH(1,1) parameter estimates often vary substantially across the subsamples defined by the structural breaks. We also find that it almost always pays to allow for structural breaks when forecasting exchange rate return volatility in real time. Combining forecasts from different models that accommodate structural breaks in volatility in various ways appears to offer a reliable method for improving volatility forecast accuracy given the uncertainty surrounding the timing and size of the structural breaks.
Radiologists should manage the radiation dose for pediatric patients to maintain reasonable diagnostic confidence. We assessed the variation in estimated radiation dose indices for pediatric ...noncontrast head CT in the United States.
Radiation dose indices for single-phase noncontrast head CT examinations in patients 18 years of age and younger were retrospectively reviewed between July 2011 and June 2016 using the American College of Radiology CT Dose Index Registry. We used the reported volume CT dose index stratified by patient demographics and imaging facility characteristics.
The registry included 295,296 single-phase pediatric noncontrast head CT studies from 1571 facilities (56% in male patients and 53% in children older than 10 years of age). The median volume CT dose index was 33 mGy (interquartile range = 22-47 mGy). The volume CT dose index increased as age increased. The volume CT dose index was lower in children's hospitals (median, 26 mGy) versus academic hospitals (median, 32 mGy) and community hospitals (median, 40 mGy). There was a lower volume CT dose index in level I and II trauma centers (median, 27 and 32 mGy, respectively) versus nontrauma centers (median, 40 mGy) and facilities in metropolitan locations (median, 30 mGy) versus those in suburban and rural locations (median, 41 mGy).
Considerable variation in the radiation dose index for pediatric head CT exists. Median dose indices and practice variations at pediatric facilities were both lower compared with other practice settings. Decreasing dose variability through proper management of CT parameters in pediatric populations using benchmarks generated by data from registries can potentially decrease population exposure to ionizing radiation.
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