32,096 research outputs found
Improving the Methodology of Training Load and Injury Risk Research: An Analysis of Analyses
No full textAvhandling (doktorgrad) - Norges idrettshøgskole, 2023Background: Sport injuries burden professional and recreational athletes. In 2021, Norwegian hospitals operated 1 462 anterior cruciate ligaments, and 62% of these happened during sports activity. To prevent injuries, it may be possible to change the training load. Unfortunately, how training load can be altered to achieve desired outcomes is unknown, because the relationship between training load and injury risk has proven difficult to study. The ability of currently used statistical methods to capture this complex relationship is either limited, or unknown. Consequently, studies have employed a plethora of statistical approaches. Systematic reviews have reported inconsistent and even conflicting findings both within and between studies, and declared the studies too variable to compare in analyses. Experts have questioned the evidence supporting training load as an injury prevention tool, and called for improved statistical methodology. Despite this, few studies have recommended alternatives, and those who have, have not tested the methods’ accuracy or precision. The validity of recommended methods is therefore unknown. To improve research on injury prevention programs, knowledge is needed on how to statistically determine the relationship of training load and injury risk.
Aims: To identify statistical methods suitable for assessing the relationship between training load and injury risk. Specifically, to find methods for dealing with 1) missing data, 2) non-linearity, 3) time-dependent effects, and 4) the effects of relative training load.
Main Methods: We analyzed three football datasets and one handball dataset: Norwegian Premier League men’s football (42 players, 38 injuries), Norwegian U-19 football (81 players, 81 injuries), Norwegian elite youth handball (205 players, 471 injuries), and Qatar Stars League (QSL) football (1 465 players, 1 977 injuries). In all Norwegian cohorts, training load was defined as the number of minutes in training/match activity multiplied by the athlete’s rating of perceived exertion on a scale from 1 to 10 (sRPE). The Norwegian Premier League data additionally had measures of distance and speed registered by Global Positioning Systems (GPS) devices in football. In the QSL cohort, training load was defined as the number of minutes in football training/activity.
The Norwegian Premier League football and Norwegian elite youth football were the basis for three simulation studies (Paper I–III). We simulated a relationship between training load and probability of injury under different scenarios of missing data, non-linearity, and time-dependent effects. With the aid of accuracy and uncertainty measures, we compared the ability of various statistical methods to model the simulated relationships in the respective scenarios.
Regression analyses were used to check whether there were any signs of non-linearity between sRPE and injury risk in the three Norwegian cohorts (Paper II), and also signs of time-dependent effects between training load and injury risk in the handball and QSL cohorts (Paper III–IV). In addition, we applied a novel approach of estimating the effect of recent training load relative to past training load on injury risk (relative training load) on the Norwegian elite U-19 and QSL data (Paper IV).
Main Results: In each of the simulations, the performance of a few methods stood out from the rest. Firstly, for handling missing data, multiple imputation using predicted mean matching had, generally, the lowest percentage bias of all compared methods, and had acceptable bias (< |5%|) up to 50% missing data in sRPE and up to 90% missing data in the total distance GPS measure. Secondly, when we modelled parabolic non-linear relationships, fractional polynomials, quadratic regression and restricted cubic splines had the lowest root-mean-squared error, and highest coverage of 95% prediction intervals. Lastly, in the simulation of time-dependent effects, the distributed lag non-linear model was the only method that accurately modelled more than one scenario. It had the lowest root-mean-squared error and the narrowest 95% confidence intervals, by far, compared with the other methods.
The handball model presented a parabolic J-shaped relationship between sRPE and injury risk (p < 0.001). The QSL model displayed time-dependent effects, where effect estimates of past training load decreased exponentially for each day in the past. The QSL model also showed highest injury risk at low levels of past training load, lowest risk at medium levels, and intermediate risk at high levels of past training load, for each level of recent training load. This demonstrated that relative training load can be modelled with this novel approach.
Conclusion: Missing data in training load should be imputed with multiple imputation using predicted mean matching. Researchers in training load and injury risk should consider the potential for non-linearity and time-dependent effects, and explore such effects by specifying fractional polynomials or restricted cubic splines in distributed lag non-linear models. Modelling recent and past training load separately can be used to study the effects of relative training load on injury risk.publishedVersionInstitutt for idrettsmedisinske fag / Department of Sports Medicin
Americans’ perceptions of and likely responses to the threat of avian influenza in the U.S. food supply
No full textHighly pathogenic avian influenza has affected poultry consumption in all affected countries as well as some countries that have not been affected. If, as some predict, there is an outbreak of avian influenza in poultry in the U.S., there will likely be serious repercussions on the entire food system.To predict what might happen if avian influenza emerged in poultry or wild birds in the U.S. researchers at the Food Policy Institute at Rutgers, the State University of New Jersey, conducted a national survey of public knowledge, attitudes, intentions, and behaviors related to the threat of avian influenza in the food supply.MethodologyA total of 1200 telephone interviews, lasting an average of 22 minutes, were completed between May 3, and June 5, 2006.2 The survey sample was selected through a random digit dial list. The sample selection procedures ensure that every household within the United States has an equal chance to be included in the survey. Each selected number was called a maximum of 15 times with calls distributed across days and times to try to reach a member of the household. The data was weighted using appropriate U.S. census weights for gender, age, race, ethnicity, and education. The cooperation rate was 60%. This paper summarizes the findings of the survey.Rutgers Food Policy Institute (FPI) Research Report RR-1106-01
Public Perceptions of Genetically Modified Foods: A National Study of American Knowledge and Opinion
No full textThis report presents the results from the second phase of a longitudinal study of Americans’ knowledge and feelings about agricultural biotechnology and how those perceptions and attitudes have changed over time. Two independent national probability samples of 1,200 adults were interviewed by phone in the spring of 2001 and 2003. While this report focuses on the findings from 2003, longitudinal comparisons are presented where appropriate. The report begins with an investigation of Americans’ awareness of the presence of genetically modified (GM) ingredients in the foods they encounter everyday. Next, the report describes Americans’ actual and perceived knowledge of science, biotechnology and food production. It then examines American opinions about GM foods in general, along with their opinions on a variety of existing and potential GM food products with direct or indirect consumer benefits. The report discusses the relationship between opinions of GM food and a variety of factors, including demographics, knowledge of biotechnology, purchasing behaviors and styles of food selection. Finally, it describes Americans’ thoughts on GM food labeling.Suggested Citation:
Hallman, W. K., Hebden, W. C., Aquino, H.L., Cuite, C.L. and Lang, J.T. 2003. Public Perceptions of Genetically Modified Foods: A National Study of American Knowledge and Opinion. (Publication number RR-1003-004). New Brunswick, New Jersey; Food Policy Institute, Cook College, Rutgers - The State University of New Jersey
Avian Influenza in Poultry: American Knowledge, Perceptions, and Responses
No full textComputer assisted telephone interviews (CATI) were conducted with a nationally representative sample of 1,200 non-institutionalized American adults (aged 18 and over) between May 3, 2006 and June 5, 2006. The results indicated:
• Avian influenza is on the national agenda
- Most Americans (93%) indicate they have heard of avian influenza.
- Nearly three-quarters of Americans say they have discussed avian influenza with someone else.
• Still, most Americans don’t know much about avian influenza
- More than half of Americans say they know ‘little’ or ‘nothing’ about avian influenza.
- On average, Americans correctly answer fewer than 60% of a series of 22 objective knowledge
questions.
• Uncertainty regarding food-related transmission
- The majority of Americans are aware that animal to human transmission of the avian influenza virus
can occur from contact with live infected birds or feces from infected birds.
- About one-third are unsure if transmission is possible from eating infected meat or eggs.
• Conflicting beliefs about preventing infection
- More than two-thirds of Americans believe the virus is present in uncooked meat of infected
chickens.
- Yet, less than half believe that proper cooking chicken kills the avian influenza virus.
- Few Americans believe infected live birds are easily recognizable; yet, many believe infected raw
meat is readily identifiable.
• Americans perceive the general risks posed by avian influenza to be low
- Americans aren’t very worried about illness with avian influenza.
- Americans report their risk of infection with avian influenza in the next year to be relatively low and
other Americans’ risk of infection to be higher, but still moderate.
• Yet, Americans see avian influenza in chicken as more risky
- The majority of Americans report greater perceived risk specifically associated with the consequences of eating chicken infected with avian influenza.
• Most Americans currently view chicken as safe and continue to eat it
- More than nine-in-ten Americans say they currently eat chicken.
- Americans report that chicken products in the U.S. are currently safe to eat.
• The proximity of avian influenza cases affects Americans likelihood of eating chicken
- The nearer avian influenza comes to the U.S., the less likely Americans are to eat chicken.
- Avian influenza does not necessarily have to emerge in the U.S. to affect poultry consumption.
• Many Americans are unlikely to eat chicken if the avian influenza virus is found inside the
U.S.
- Americans say they are relatively unlikely to eat chicken in the U.S. if avian influenza is found in wild
birds in the U.S. or if someone became sick with avian influenza from eating chicken in the U.S.
- Americans report being least likely to eat chicken in the U.S. if avian influenza was found in chickens
on farms in the U.S. and 39% report that they would definitely not eat chicken.
- Americans report reluctance to eat any chicken products if U.S. chickens are infected.
• Even with a strong, specific assurance of safety, many Americans report that they would be
unlikely to eat chicken again if the avian influenza virus is found inside the U.S.
- One-fifth (20%) say they would never eat chicken again.
- Those participants who said they would eat chicken again, report that it would take an average of 144 days for them to start eating it again (SD=337.67; Mdn=42).Suggested Citation:
Condry, S. C., Hallman, W. K., Vata, M., & Cuite, C. L. (2007). Avian influenza in poultry: Americans’
knowledge, perceptions, and responses. (Publication number RR-0507-014). New Brunswick, New Jersey: Rutgers, the State University of New Jersey, Food Policy Institute
∑_(l+m=k,l,m≥0) ((α+l-1)¦l) ((β+m-1)¦m)=((α+β+k-1)¦k) and its application to negative binomial distribution
No full textWe prove here the following equation: ∑_(l+m=k,l,m≥0) ((α+l-1)¦l) ((β+m-1)¦m)=((α+β+k-1)¦k) and give its application to prove the reproductive property of the negative binomial distribution.
These finite sum equation involving binomial coefficients and proof of the reproductive property are not known as far as the author knows.論文(Article)departmental bulletin pape
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Lower K- and L-theory
No full textThis is the first unified treatment in book form of the lower K-groups of Bass and the lower L-groups of the author
Public Response to the Contaminated Spinach Recall of 2006
No full textOn September 14, 2006, the U.S. Food and Drug Administration (FDA) issued an advisory to consumers not to eat bagged fresh spinach because of suspected contamination by E. coli O157:H71. This advisory was based on information provided to the FDA by the Centers for Disease Control and Prevention (CDC) concerning a multi-state foodborne illness outbreak possibly associated with the consumption of fresh spinach. The FDA also informed the public that E. coli O157:H7 causes diarrhea, often with bloody stools, and urged those who believed they experienced symptoms of illness after consuming bagged spinach to contact their health care providers.
The following day, the advisory was expanded to include all fresh spinach because the FDA had been informed that bagged spinach was sometimes sold in an un-bagged form at the retail level. Simultaneously, a series of voluntary recalls of fresh spinach began nationwide, as stores and restaurants quickly removed fresh spinach from their shelves and menus. By then, however, some of the contaminated spinach had already been consumed, with most people having already become ill between August 19 and September 5, 2006. As the investigation continued, the focus narrowed to products from Natural Selection Foods, LLC, of San Juan Bautista, California, with "Best if Used by Dates" of August 17, 2006 through October 1, 2006.
On September 20, the FDA issued an updated press release, advising consumers to continue to avoid consuming fresh spinach or products containing fresh spinach. They added however, that it was safe to eat frozen spinach, canned spinach and spinach included in pre-made meals manufactured by food companies. The following day, the FDA issued a statement that they, working closely with the CDC and the State of California, had determined that the spinach implicated in the outbreak had been grown in Monterey, San Benito, and Santa Clara counties in California. The FDA was cautious in stating that produce other than spinach grown in these counties had not been implicated in the outbreak, however, the advisory against eating spinach was still in effect.
Finally, on September 22, the FDA advised the public that they could be confident in consuming spinach grown outside the three counties in California that had been implicated in the outbreak. They added that “industry is working to get spinach from areas not implicated in the current E. coli O157:H7 outbreak back on the market”; suggesting that the incident was over. However, as late as October 6, the FDA continued to remind retailers, food service operators and consumers that they should not sell or consume raw spinach or blends that might contain spinach that were “the subject of the earlier recalls.”
Ultimately, nearly 200 people in 26 states were reported to the CDC as having potentially been infected with the outbreak strain of E. coli O157:H79. More than 100 of these cases were hospitalized, and 31 developed a form of kidney failure called hemolytic uremic syndrome (HUS). This resulted in the deaths of three people (two elderly women and a two-year old boy) in confirmed cases of infection believed to be associated with the outbreak.
Due to the nature, scope, and significance of this contamination incident, and the potential lessons that might be learned from it, the Food Policy Institute (FPI) at Rutgers, the State University of New Jersey undertook an analysis of the information that key actors attempted to deliver as events unfolded, the media coverage of those messages and events, and the information that consumers received, remembered, and acted upon. This report focuses on the third portion of this analysis; that is, what did consumers know, where did they get that
information, and what did they do in response to the advisories issued by the FDA warning them not to eat fresh spinach.Food Policy Institute Research Report # RR-0107-013
Determination of K shell XRF parameters and K to L shell vacancy transfer probabilities of ferromagnetic 3d transition metals
No full textIn this study, K shell X-ray fluorescence cross-sections (sigma K alpha, sK beta and sigma K), K shell fluorescence yields (omega K) and K to L shell vacancy transfer probabilities (eta KL) of ferromagnetic 3d transition metals (Fe, Co, Ni) were investigated to understand how the relationship between ferromagnetism and these values changes with atomic number by using energy dispersive X-ray fluorescence (EDXRF) technique. The all obtained experimental and theoretical results were comparatively given as a function of the atomic number. It was clearly observed that all of the investigated parameters depend on the atomic number and the ferromagnetism state of the atom
K-theory for group C*-algebras
No full textThese notes are based on a lecture course given by the first author in the Sedano Winter School on K-theory held in Sedano, Spain, on January 22-27th of 2007. They aim at introducing K-theory of C*-algebras, equivariant K-homology and KK-theory in the context of the Baum-Connes conjectur
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