Effectiveness of Small-Sided Games in Improving Repeated Sprint Ability In Soccer: a systematic review

Introduction: Small-sided games (SSGs) for soccer typically use 2-5 players per team on a smaller field. Soccer coaches employ SSGs to simulate specific aspects of full-sized soccer and optimize practice time by working on multiple match components at once. This review was conducted to see if SSGs also improved the physical ability of soccer players, specifically a player’s repeated sprint ability (RSA). Methods: Research databases were searched using specific keywords. Articles were filtered to identify suitable articles for the review. The 4 articles identified were evaluated on participant characteristics, program prescription, load dosage, playing area dimensions, and RSA scores Results: Eighty articles were identified during the initial search, but only 4 met all inclusion criteria. The overall conclusion from this limited sample of articles was that SSGs improved RSA scores in specific categories. Conclusions: SSGs can be recommended to professionals as a potential method for improving physical performance capacity of soccer players. Additional high quality studies are needed to better clarify the impact of specific SSG rules and field dimensions for optimizing RSA improvement

Pluralism without Genic Causes?

Since the fundamental challenge that I laid at the doorstep of the pluralists was to defend, with nonderivative models, a strong notion of genic cause, it is fatal that Waters has failed to meet that challenge. Waters agrees with me that there is only a single cause operating in these models, but he argues for a notion of causal ‘parsing’ to sustain the viability of some form of pluralism. Waters and his colleagues have some very interesting and important ideas about the sciences, involving pluralism and parsing or partitioning causes, but they are ideas in search of an example. He thinks he has found an example in the case of hierarchical and genic selection. I think he has not

Pluralism without Genic Causes?

Since the fundamental challenge that I laid at the doorstep of the pluralists was to defend, with nonderivative models, a strong notion of genic cause, it is fatal that Waters has failed to meet that challenge. Waters agrees with me that there is only a single cause operating in these models, but he argues for a notion of causal ‘parsing’ to sustain the viability of some form of pluralism. Waters and his colleagues have some very interesting and important ideas about the sciences, involving pluralism and parsing or partitioning causes, but they are ideas in search of an example. He thinks he has found an example in the case of hierarchical and genic selection. I think he has not

Determining CaMKII Variant Activities and Their Roles in Human Disease

Ca2+/calmodulin-dependent protein kinase II (CaMKII) is involved in Ca2+signaling throughout the body. CaMKII is enriched in the hippocampus and required for learning and memory formation. Four highly conserved genes encode CaMKII in vertebrates: A, B, G, and D. All CaMKII variants are constituted of a kinase domain, regulatory segment, variable linker, and hub domain. These domains comprise an individual subunit which oligomerize together via the hub domain to form multimeric holoenzymes. These four genes are most variable in the linker domain due to extensive alternative splicing. The variable linker significantly impacts the activation of CaMKIIA. Herein, I attempt to develop an in vitro assay which resembles physiological activation of CaMKII via Ca2+ oscillations. I provide preliminary data which indicate that alternative splicing of the variable linker in CaMKIIA modulates the Ca2+ frequency dependent autonomy of these variants. Additionally, neuronal CaMKII variants of CaMKIIA and CaMKIIB decode Ca2+ oscillations into different levels of autonomous activity. Lastly, I assess the impacts of three de novo mutations (Q274P, R275H, and F294S) on Ca2+/CaM sensitivity in CaMKIID by providing data that these 3 mutants increase the sensitivity of CaMKIId to Ca2+/CaM and that Q274P and F294S mutants display Ca2+/CaM independent activity

Finite-Rate Chemistry Effects in Turbulent Premixed Combustion

In recent times significant public attention has been drawn to the topic of combustion. This has been due to the fact that combustion is the underlying mechanism of several key challenges to modern society: climate change, energy security (finite reserves of fossil fuels) and air pollution. The further development of combustion science is undoubtedly necessary to find improved solutions to manage these combustion science related challenges in the near and long term future. Combustion is essentially an exothermic process, this exothermicity or heat release essentially occurs at small scales, by small scales it meant these scales are small relative to the fluid length scales, for example heat release layer thicknesses in flames are typically much less than the fluid integral length scales. As heat release occurs at small scales this means that in turbulent combustion the small scales of the turbulence (which can be of the order of the heat release layer thickness) can possibly interact and influence the heat release and thus chemistry of the flame reaction zone. Premixed combustion is a combustion mode where the fuel and oxidiser are completely premixed prior to the flame reaction zone, this mode of combustion has been shown to be a promising method to maximise combustion efficiency and minimise pollutant formation. The continued and further application of premixed combustion to practical applications is limited by the current understanding of turbulent premixed combustion, these limitations in understanding are linked to the specific flame phenomena that can significantly influence premixed combustion in a combustion device, examples of such phenomena are: flame flashback, flame extinction and fuel consumption rate – all phenomena that are influenced by the interaction of the small scales of turbulence and chemistry. It is the study and investigation of the interaction of turbulence and chemistry at the small scales (termed finite-rate chemistry) in turbulent premixed flames that is the aim of this thesis which is titled “Finite-rate chemistry effects in turbulent premixed combustion”. Two very closely related experimental burner geometries have been developed in this thesis: the Piloted Premixed Jet Burner (PPJB) and the Premixed Jet Burner (PJB). Both feature an axisymmetric geometry and exhibit a parabolic like flow field. The PPJB and PJB feature a small 4mm diameter central jet from which a high velocity lean-premixed methane-air mixture issues. Surrounding the central jet in the PPJB is a 23.5mm diameter pilot of stoichiometric methane-air products, the major difference between the PPJB and the PJB is that the PJB does not feature a stoichiometric pilot. The pilot in the PPJB provides a rich source of combustion intermediates and enthalpy which promotes initial ignition of the central jet mixture. Surrounding both the central jet and pilot is a large diameter hot coflow of combustion products. It is possible to set the temperature of the hot coflow to the adiabatic flame temperature of the central jet mixture to simulate straining and mixing against and with combustion products without introducing complexities such as quenching and dilution from cold air. By parametrically increasing the central jet velocity in the PPJB it is possible to show that there is a transition from a thin conical flame brush to a flame that exhibits extinction and re-ignition effects. The flames that exhibit extinction and re-ignition effects have a luminous region near the jet exit termed the initial ignition region. This is followed by a region of reduced luminosity further downstream termed the extinction region. Further downstream the flame luminosity increases this region is termed the re-ignition region. For the flames that exhibit extinction and re-ignition it is proposed that intense turbulent mixing and high scalar dissipation rates drives the initial extinction process after the influence of the pilot has ceased (x/D>10). Re-ignition is proposed to occur downstream where turbulent mixing and scalar dissipation rates have decreased allowing robust combustion to continue. As the PJB does not feature a pilot, the flame stabilisation structure is quite different to the PPJB. The flame structure in the PJB is essentially a lifted purely premixed flame, which is an experimental configuration that is also quite unique. A suite of laser diagnostic measurements has been parametrically applied to flames in the PPJB and PJB. Laser Doppler Velocimetry (LDV) has been utilised to measure the mean and fluctuating radial and axial components of velocity at a point, with relevant time and length scale information being extracted from these measurements. One of the most interesting results from the LDV measurements is that in the PPJB the pilot delays the generation of high turbulence intensities, for flames that exhibit extinction the rapid increase of turbulence intensity after the pilot corresponds to the start of the extinction region. Using the LDV derived turbulence characteristics and laminar flame properties and plotting these flames on a traditional turbulent regime diagram indicates that all of the flames examined should fall in the so call distributed reaction regime. Planar imaging experiments have been conducted for flames using the PPJB and PJB to investigate the spatial structure of the temperature and selected minor species fields. Results from two different simultaneous 2D Rayleigh and OH PLIF experiments and a simultaneous 2D Rayleigh, OH PLIF and CH2O PLIF experiment are reported. For all of the flames examined in the PPJB and PJB a general trend of decreasing conditional mean temperature gradient with increasing turbulence intensity is observed. This indicates that a trend of so called flame front thickening with increased turbulence levels occurs for the flames examined. It is proposed that the mechanism for this flame front thickening is due to eddies penetrating and embedding in the instantaneous flame front. In the extinction region it is found that the OH concentration is significantly reduced compared to the initial ignition region. In the re-ignition region it is found that the OH level increases again indicating that an increase in the local reaction rate is occurring. In laminar premixed flames CH2O occurs in a thin layer in the reaction zone, it is found for all of the flames examined that the CH2O layer is significantly thicker than the laminar flame. For the high velocity flames beyond x/D=15, CH2O no longer exist in a distinct layer but rather in a near uniform field for the intermediate temperature regions. Examination of the product of CH2O and OH reveals that the heat release in the initial ignition region is high and rapidly decreases in the extinction region, an increase in the heat release further downstream is observed corresponding to the re-ignition region. This finding corresponds well with the initial hypothesis of an extinction region followed by a re-ignition region that was based on the mean chemiluminescence images. Detailed simultaneous measurement of major and minor species has been conducted using the line Raman-Rayleigh-LIF technique with CO LIF and crossed plane-OH PLIF at Sandia National Laboratories. By measuring all major species it is also possible to define a mixture fraction for all three streams of the PPJB. Using these three mixture fractions it was found that the influence of the pilot in the PPJB decays very rapidly for all but the lowest velocity flames. It was also found that for the high velocity flames exhibiting extinction, a significant proportion of the coflow fluid is entrained into the central jet combustion process at both the extinction region and re-ignition regions. The product of CO and OH conditional on temperature is shown to be proportion to the net production rate of CO2 for certain temperature ranges. By examining the product of CO and OH the hypothesis of an initial ignition region followed by an extinction region then a re-ignition region for certain PPJB flames has been further validated complementing the [CH2O][OH] imaging results. Numerical modelling results using the transported composition probability density function (TPDF) method coupled to a conventional Reynolds averaged Naiver Stokes (RANS) solver are shown in this thesis to successfully predict the occurrence of finite-rate chemistry effects for the PM1 PPJB flame series. To calculate the scalar variance and the degree of finite-rate chemistry effects correctly, it is found that a value of the mixing constant ( ) of approximately 8.0 is required. This value of is much larger than the standard excepted range of 1.5-2.3 for that has been established for non-premixed combustion. By examining the results of the RANS turbulence model in a non-reacting variable density jet, it is shown that the primary limitation of the predictive capability of the TPDF-RANS method is the RANS turbulence model when applied to variable density flows

The Lion, The Rooster, And The Union: National Identity in the Belgian Clandestine Press, 1914-1918

Significant research has been conducted on the trials and tribulations of Belgium during the First World War. While amateur historians can often summarize the “Rape of Belgium” and cite nationalism as a cause of the war, few people are aware of the substantial contributions of the Belgian people to the war effort and their significance, especially in the historical context of Belgian nationalism. Relatively few works have been written about the underground press in Belgium during the war, and even fewer of those works are scholarly. The Belgian underground press attempted to unite the country's two major national identities, Flemings and Walloons, using the German occupation as the catalyst to do so. Belgian nationalists were able to momentarily unite the Belgian people to resist their German occupiers by publishing pro-Belgian newspapers and articles. They relied on three pillars of identity—Catholic heritage, loyalty to the Belgian Crown, and anti-German sentiment. While this expansion of Belgian identity dissipated to an extent after WWI, the efforts of the clandestine press still serve as an important framework for the development of national identity today. By examining how the clandestine press convinced members of two separate nations, Flanders and Wallonia, to re-imagine their community to the nation of Belgium, historians can analyze the successful expansion of a nation in a war-time context

Multiparametric 3 Tesla magnetic resonance imaging as a clinical tool to characterize prostate cancer

Scientists have come a long way in understanding prostate cancer as a disease and how its progression affects the men who develop it. Prostate adenocarcinoma may be present without causing clinical symptoms. Prostate cancer may metastasize, which increases the likelihood of fatality. The cause of the disease is still not completely clear, but genetics, race, tissue damage, history of previous infections, diet, and environmental influences appear to play a role in its development. Magnetic resonance imaging (MRI) has become an excellent clinical tool to characterize prostate cancer without the use of ionizing radiation or surgery. It is concluded that MRI is the optimal imaging modality to achieve detection, characterization, and staging of intracapsular and extracapsular prostate disease. The advances in MRI technology, particularly 3 Tesla, allows for reduced surgical intervention thus improving quality of life for patients with the disease