Positron emission tomography

Positron-emission tomography is a nuclear medicine functional imaging technique, used to observe metabolic processes in the body as an aid to the diagnosis of disease. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radioligand, most fluorine-18, introduced into the body on a biologically active molecule called a radioactive tracer. Different ligands are used for different imaging purposes, depending on what the radiologist/researcher wants to detect. Three-dimensional images of tracer concentration within the body are constructed by computer analysis. In modern PET computed tomography scanners, three-dimensional imaging is accomplished with the aid of a computed tomography X-ray scan performed on the patient during the same session, in the same machine. If the biologically active tracer molecule chosen for PET is fluorodeoxyglucose, an analogue of glucose, the concentrations of tracer imaged will indicate tissue metabolic activity as it corresponds to the regional glucose uptake.

Use of this tracer to explore the possibility of cancer metastasis is the most common type of PET scan in standard medical care. Metabolic trapping of the radioactive glucose molecule allows the PET scan to be utilized; the same tracer may be used for PET investigation and diagnosis of types of dementia. Less other radioactive tracers but not always labeled with fluorine-18, are used to image the tissue concentration of other types of molecules of interest. One of the disadvantages of PET scanners is their operating cost. A similar imaging process to PET is single-photon emission computed tomography, which uses radioligands to detect molecules in the brain, is less expensive. PET is both research tool, it is used in clinical oncology, for clinical diagnosis of certain diffuse brain diseases such as those causing various types of dementias. PET is an important research tool to map normal human brain and heart function, support drug development. PET is used in pre-clinical studies using animals, where it allows repeated investigations into the same subjects.

This is valuable in cancer research, as it results in an increase in the statistical quality of the data and reduces the numbers of animals required for a given study. Alternative methods of scanning include x-ray computed tomography, magnetic resonance imaging and functional magnetic resonance imaging and single-photon emission computed tomography. While some imaging scans such as CT and MRI isolate organic anatomic changes in the body, PET and SPECT are capable of detecting areas of molecular biology detail. PET scanning does this using radiolabelled molecular probes that have different rates of uptake depending on the type and function of tissue involved. Changing of regional blood flow in various anatomic structures can be visualized and quantified with a PET scan. PET imaging is best performed using a dedicated PET scanner, it is possible to acquire PET images using a conventional dual-head gamma camera fitted with a coincidence detector. Although the quality of gamma-camera PET is lower and acquisition is slower, this method allows institutions with low demand for PET to provide on-site imaging, instead of referring patients to another centre or relying on a visit by a mobile scanner.

PET scanning with the tracer fluorine-18 fluorodeoxyglucose, called FDG-PET, is used in clinical oncology. This tracer is a glucose analog, taken up by glucose-using cells and phosphorylated by hexokinase. A typical dose of FDG used in an oncological scan has an effective radiation dose of 7.6 mSv. Because the hydroxyl group, replaced by fluorine-18 to generate FDG is required for the next step in glucose metabolism in all cells, no further reactions occur in FDG. Furthermore, most tissues cannot remove the phosphate added by hexokinase; this means that FDG is trapped in any cell that takes it up until it decays, since phosphorylated sugars, due to their ionic charge, cannot exit from the cell. This results in intense radiolabeling of tissues with high glucose uptake, such as the normal brain, liver and most cancers; as a result, FDG-PET can be used for diagnosis and monitoring treatment of cancers in Hodgkin's lymphoma, non-Hodgkin lymphoma, lung cancer. A few other isotopes and radiotracers are being introduced into oncology for specific purposes.

For example, 11C-labelled metomidate, has been used to detect tumors of adrenocortical origin. FDOPA PET/CT, in centers which offer it, has proven to be a more sensitive alternative to finding, localizing, pheochromocytoma than the MIBG scan. Neurology: PET neuroimaging is based on an assumption that areas of high radioactivity are associated with brain activity. What is measured indirectly is the flow of blood to different parts of the brain, which is, in general, believed to be correlated, has been measured using the tracer oxygen-15; because of its 2-minute half-life, O-15 must be piped directly from a medical cyclotron for such uses, difficult. Example: In practice, since the brain is a rapid user of glucose, since brain pathologies such as Alzheimer's disease decrease brain metabolism of both glucose and oxygen in tandem, standar

Stock market cycles

Stock market cycles are the long-term price patterns of stock markets and are associated with general business cycles. They are key to technical analysis where the approach to investing is based on cycles or repeating price patterns; the efficacy of the predictive nature of these cycles is controversial and some of these cycles have been quantitatively examined for statistical significance. Well known cycles include: The lunar cycle Annual seasonality known as Sell in May or the Halloween indicator as well as the January effect and July effect; the four-year United States presidential election cycle in the US. The 17.6 Year Stock Market Cycle The 60 year Kondratiev cyclesInvestment advisor Mark Hulbert has tracked the long-term performance of Norman Fosback’s a Seasonality Timing System that combines month-end and holiday-based buy/sell rules. According to Hulbert, this system has been able to outperform the market with less risk. According to Stan Weinstein there are four stages in a major cycle of stocks, stock sectors or the stock market as a whole.

These four stages are base building upward advancement culmination decline. Cyclical cycles last 4 years, with bull and bear market phases lasting 1–3 years, while Secular cycles last about 30 years with bull and bear market phases lasting 10–20 years, it is accepted that in early 2011 the US stock market is in a cyclical bull phase as it has been moving up for a number of years. It is generally accepted that it is in a secular bear phase as it has been stagnant since the stock market peak in 2000; the longer term Kondratiev cycles are two Secular cycles in length and last 60 years. The end of the Kondratiev cycle is accompanied by economic troubles, such as the original Great Depression of the 1870s, the Great Depression of the 1930s and the current Great Recession; the presence of multiple cycles of different periods and magnitudes in conjunction with linear trends, can give rise to complex patterns, that are mathematically generated through Fourier analysis. In order for an investor to more visualise a longer term cycle, they sometimes will superimpose a shorter term cycle such as a moving average on top of it.

A common view of a stock market pattern is one. In this kind of a chart one may create and observe any of the following trends or trend relationships: A long-term trend, which may appear as linear Intermediate term trends and their relationship to the long-term trend Random price movements or consolidation and its relationship to one of the aboveFor example, if one looks at a longer time-frame, the current trend may appear as a part of a larger cycle. Switching to a shorter time-frame, may reveal price movements that appear as shorter-term trends in contrast to the primary trend on the six-month, daily time period, chart. A stock market trader will use several "screens" or charts on their computer with different time frames and price intervals in order to try to gain information for making profitable buying and selling decisions. Expert traders will emphasize the use of multiple time frames for successful trading. For example, Alexander Elder suggests a Triple Screen approach. Longer-term screen: To identify the long-term trend and opportunities Middle screen: To identify the best day on which to locate a buy or sell opportunity Finer screen: To identify the optimum intra-day price at which to buy or sell a given security Conference Board - Consumer Confidence, Conference Board’s Present Situation Index - Major turns in the Conference Board’s Present Situation Index tend to precede corresponding turns in the unemployment rate—particularly at business cycle peaks.

Major upturns in the index tend to foreshadow cyclical peaks in the unemployment rate, which occur well after the end of a recession. Another useful feature of the index that can be gleaned from the charts is its ability to signal sustained downturns in payroll employment. Whenever the year-over-year change in this index has turned negative by more than 15 points, the economy has entered into a recession; the most useful methods to predict business cycle use methods similar to the organization as Eurostat, OECD and Conference Board. Federal Reserve Bank of Chicago - Chicago Fed National Activity Index Diffusion Index - The Chicago Fed National Activity Index Diffusion Index is a macroeconomic model of Business Cycle Models. “CFNAI Diffusion Index signals the beginnings and ends of recessions on average one month earlier than the CFNAI-MA3.” … the crossing of a -0.35 threshold by the CFNAI Diffusion Index signaled an increased likelihood of the beginning and end of a recession... Federal Reserve Bank of Philadelphia - Aruoba-Diebold-Scotti Business Conditions Index - is published by the Federal Reserve Bank of Philadelphia.

The average value of the ADS index is zero. Progressively bigger positive values indicate progressively better-than-average conditions, whereas progressively more negative values indicate progressively worse-than-average conditions. Federal Reserve Bank of New York - Yield Curve - the slope of the yield curve is one of the most powerful predictors of future economic growth and recessions. BofA Merrill Lynch - Global Wave - has indicators from around the world such as industrial confidence, consumer confidence, estimate revisions, producer prices, capacity utilization, earnings revisions, credit spr

Bad Reputation (Glee)

"Bad Reputation" is the seventeenth episode of the American television series, Glee. The episode premiered on the Fox network on May 4, 2010, it was directed by Elodie Keene, written by series creator Ian Brennan. In "Bad Reputation", cheerleading coach Sue Sylvester is publicly ridiculed when a video of her dancing to Olivia Newton-John's "Physical" is posted on YouTube. A salacious list about members of the glee club circulates the school, leading certain members to try to earn themselves a bad reputation. Newton-John guest-stars as herself in the episode, Molly Shannon makes her first appearance in a recurring role. Following their romance in the episode "Mash-Up", club members Rachel and Puck are reunited, a decision made by the producers due to the unexpected popularity of the pairing; the episode features cover versions of five songs, all of which were released as singles, available for digital download, two of which are included on the soundtrack album Glee: The Music, Volume 3 – Showstoppers.

"Bad Reputation" was watched by 11.62 million American viewers and received mixed reviews from critics. Darren Franich of Entertainment Weekly and Bobby Hankinson of the Houston Chronicle both considered it a return to form following disappointing episodes. Franich praised the episode's cover version of "Ice Ice Baby" by Vanilla Ice, which in contrast was criticized by Raymund Flandez of The Wall Street Journal and Gerrick D. Kennedy of the Los Angeles Times, with Kennedy deeming the performance his least favorite moment of the entire series thus far; when Kurt steals a video of cheerleading coach Sue Sylvester performing Olivia Newton-John's "Physical" to a Jazzercise routine, the glee club members decide to post it on YouTube as a prank. The video becomes a viral hit and Sue is mortified. In retaliation, she gives Principal Figgins a list she has found, called a "glist", which ranks the students in the glee club based on a scale of sexual promiscuity; the list goes: Quinn, Puck, Jesse, Mike and Rachel, from most to least.

Figgins tells club director Will Schuester that he must either find the creator of the list, or he will be forced to disband the glee club and suspend all of its members. Will reprimands the club members, for their weekly club assignment, he has the students find songs with bad reputations and rehabilitate them, performing Vanilla Ice's "Ice Ice Baby" as an example. Sue is laughed at by her co-workers, who have seen the video, is mocked by new alcoholic astronomy teacher and badminton coach Brenda Castle. Sue is reminded by her sister, who has Down Syndrome, that when they were hurt as children they would volunteer at an animal shelter as a reminder there was always someone less fortunate than themselves. In light of her sister's advice, Sue decides to act as a therapist to guidance counselor Emma Pillsbury, informing her that Will has been unfaithful to her. Emma confronts Will in the teachers' lounge. Kurt, Mercedes and Tina are upset over not being included on the list, while Brittany is puzzled at not being listed among the top three, given that she has made out with everyone in the school: boys and the janitor.

They perform a rendition of "U Can't Touch This" in the school library to cause a disruption in the hope of earning a bad reputation, but their plan backfires when the librarian asks them to perform it at her church's Sunday service. Next, Kurt confesses to Sue that he is the one who stole her video, expecting to be punished and gain a more dangerous reputation. Instead, she thanks him, having been contacted by Olivia Newton-John, who had seen Sue's video and requested her help remaking the "Physical" video; the song's re-release gains Sue a position in the top 700 recording artists, which ends the ridicule of her colleagues. She donates her share of the profits to her sister's residential care facility. After apologizing to Emma and presenting her with flowers, Will sees a depressed-looking Quinn in the hallway and realizes that she is responsible for the list, he confronts Quinn. To prevent her from being suspended, Will lies to Figgins that no culprit has been found, but convinces him that as no new lists have been posted, the matter should be dropped.

Rachel asks Puck to assist her in the glee club assignment, creating a video for David Geddes' "Run Joey Run". But she secretly recruits her ex-boyfriend Finn and her current boyfriend Jesse St. James, triple-casting them in the role of her film boyfriend, Joey, in a bid to improve her glist rating; when Rachel plays the video in class, all three are surprised and angered by her deception. Jesse breaks up with Rachel as a result, she sings Bonnie Tyler's "Total Eclipse of the Heart" as the club members walk out of the classroom, leaving her behind. Recurring characters who appear in the episode are glee club members Brittany, Santana Lopez, Mike Chang, Matt Rutherford and Jesse St. James, former glee club director Sandy Ryerson, football coach Ken Tanaka and Sue's sister Jean Sylvester. Mary Jo Catlett appears as widowed teacher Mrs. Carlisle, Molly Shannon makes her first appearance in a recurring role as new astronomy teacher and badminton coach Brenda Castle. Special guest star Olivia Newton-John appears as herself.

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