The importance of the International Tennis Federation's junior boys' circuit in the development of professional tennis players

The relationship between junior boys' tennis success, as measured by a top 20 International Tennis Federation's Junior Circuit (ITFJC) ranking, and subsequent ranking accomplishments in professional men's tennis is discussed. The names, countries, and birthdates of all players to achieve a top 20 ITFJC boys' year-end ranking from 1992 to 1998 were recorded. The progress of these players through the professional ranks was then tracked to the end of 2004. Results indicate that 91% of top 20-ranked boys achieved a professional men's ranking, while a stepwise regression analysis revealed junior ranking (JR) to be a predictor of future, professional ranking (beta = 0.232, r(2) = 0.054, p < 0.05). A regression equation [predicted professional rank = 78.17 + 6.31*(JR)] accounted for a significant amount of variance in professional ranking. For male players, therefore, the achievement of a top 20 junior ranking appears to be a reasonable yardstick for future, professional success. The type of surface upon which junior players develop their games was also shown to influence professional ranking highs, with play on clay courts or a combination of clay and hard courts helping to produce higher, professionally ranked players than hard court play alone (p< or = 0.01).     

Is microrheometry affected by channel deformation?

Microrheometry is very important for exploring rheological behaviours of several systems when conventional techniques fail. Microrheometrical measurements are usually carried out in microfluidic devices made of Poly(dimethylsiloxane) (PDMS). Although PDMS is a very cheap material, it is also very easy to deform. In particular, a liquid flowing in a PDMS device, in some circumstances, can effectively deform the microchannel, thus altering the flow conditions. The measure of the fluid relaxation time might be performed through viscoelasticity induced particle migration in microfluidics devices. If the channel walls are deformed by the flow, the resulting measured value of the relaxation time could be not reliable. In this work, we study the effect of channel deformation on particle migration in square-shaped microchannel. Experiments are carried out in several PolyEthylene Oxyde solutions flowing in two devices made of PDMS and Poly(methylmethacrylate) (PMMA). The relevance of wall rigidity on particle migration is investigated, and the corresponding importance of wall rigidity on the determination of the relaxation time of the suspending liquid is examined.     

Aerodynamic behaviour of single sport jersey fabrics with different roughness and cover factors

Wind tunnel testing has been carried out on nine-knitted single jersey fabrics (100% polyester) using cylinder and leg models to determine its aerodynamic behaviour over a range of speeds (20–80 km/h) representative of sports activities. Strong correlation between fabric manufacturing (cover factor) and fabric roughness and aerodynamic parameters has been established. Similar aerodynamic behaviour of fabrics was observed when tested on the cylinder model and on the leg model.     

Market information approaches, product innovativeness, and firm performance: An empirical study in the fashion industry

In this study the authors propose a distinction between two approaches to market information, rooted in the marked-based learning theory. The two approaches are conceptualized and operationalized on the basis of their differences along three processes: generation, dissemination and use of market information. In the retrospective approach, the generation process is based on expressed customer needs and extant market relations; the dissemination is based on formal mechanisms; the use process is more instrumental. In the forward-looking approach, the generation process is based on latent customer needs and on the evolutionary patterns of the future market relations; the dissemination process is more informal; the use of information is more conceptual. A series of hypotheses concerning the relationships between these approaches, product innovativeness and firm performance are tested on a sample of Italian fashion firms. Results suggest that the two approaches are complementary for firm performance, but have opposite effects on product innovativeness: while a forward-looking approach is positively related to product innovativeness, a retrospective approach seems to be negatively related. The results also shed light on how market information approaches and product innovativeness jointly affect firm performance.     

Conservation of historical reinforced concrete structures damaged by carbonation induced corrosion by means of electrochemical realkalisation

Electrochemical realkalisation is a technique aimed at stopping rebar corrosion in carbonated concrete. The alkalinity of the concrete around the rebars is restored, and an environment favourable to the passivation of steel is re-created. The technique is based on the application of a DC current from an anode, placed on the external surface of the concrete, and the rebar. The anode is usually embedded in cellulose pulp soaked with a solution of sodium or potassium carbonate. The rebar and the anode are connected to a DC current feeder, the rebar to the negative terminal and the anode to the positive terminal. The applied current produces alkalinity at the surface of the rebar, while the alkaline electrolyte in which the anode is immersed penetrates from the external surface. In this way the concrete is realkalised, its protective characteristics towards the steel are restored and rebars can return to passive conditions. The treatment is temporary: this feature makes it very attractive in the field of historical buildings and cultural heritage, where the conservation of the original materials and surfaces is often a stringent requirement in the design of the repair. This paper shows the advantages of this technique applied to historical structures by describing the application to a bell tower built in the 1920s. The electrochemical realkalisation treatment was applied to eight columns on the bell tower where a traditional repair (based on the substitution of carbonated concrete with a repair mortar) would have been practically impossible. The application of the treatment followed two steps: initially, a trial was made on two sections of two columns, so as to calibrate the process parameters such as current density, time length and type of anode. Subsequently, the treatment was applied to all the columns. The analyses carried out on the concrete after the application of the treatment showed that the protection to the reinforcement was mainly connected to the alkaline layer produced around the steel, which is expected to prevent further corrosion of the steel.     

Applying an optical space-time coding method to enhance light scattering signals in microfluidic devices

An "optical space-time coding method" was applied to microfluidic devices to detect the forward and large angle light scattering signals for unlabelled bead and cell detection. Because of the enhanced sensitivity by this method, silicon pin photoreceivers can be used to detect both forward scattering (FS) and large angle (45-60°) scattering (LAS) signals, the latter of which has been traditionally detected by a photomultiplier tube. This method yields significant improvements in coefficients of variation (CV), producing CVs of 3.95% to 10.05% for FS and 7.97% to 26.12% for LAS with 15 μm, 10 μm, and 5 μm beads. These are among the best values ever demonstrated with microfluidic devices. The optical space-time coding method also enables us to measure the speed and position of each particle, producing valuable information for the design and assessment of microfluidic lab-on-a-chip devices such as flow cytometers and complete blood count devices.     

A microfluidics assisted porous silicon array for optical label-free biochemical sensing

A porous silicon (PSi) based microarray has been integrated with a microfluidic system, as a proof of concept device for the optical monitoring of selective label-free DNA-DNA interaction. A 4 × 4 square matrix of PSi one dimensional photonic crystals, each one of 200 μm diameter and spaced by 600 μm, has been sealed by a polydimethylsiloxane (PDMS) channels circuit. The PSi optical microarray elements have been functionalized by DNA single strands after sealing: the microfluidic circuit allows to reduce significantly the biologicals and chemicals consumption, and also the incubation time with respect to a not integrated device. Theoretical calculations, based on finite element method, taking into account molecular interactions, are in good agreement with the experimental results, and the developed numerical model can be used for device optimization. The functionalization process and the interaction between DNA probe and target has been monitored by spectroscopic reflectometry for each PSi element in the microchannels.     

Resistance to carbonation of concrete after re-alkalization by absorption of sodium carbonate solution

The paper presents experimental research on the durability of a non-conventional technique for the repair of reinforced concrete damaged by carbonation-induced corrosion of steel reinforcement. The technique is called electrochemical re-alkalization and is often considered as an option for the repair of buildings, structures, and other artefacts made of reinforced concrete, for which conservation requirements are becoming increasingly important, in spite of their relatively young age. Absorption of a sodium carbonate solution is one of the processes that lead to concrete re-alkalization. The aim of the work is to investigate the contribution of this process to preventing future carbonation of re-alkalized concrete. Concrete specimens with six different compositions were initially carbonated, then re-alkalized through absorption of a sodium carbonate solution, and then exposed again to carbonation (re-carbonation). The results showed that the pH of concrete after re-carbonation was only slightly lower compared to that of re-alkalized concrete, highlighting a contribution of the treatment in preventing future pH reduction.     

Twitter Use During TV: A Full-Season Analysis of #serviziopubblico Hashtag

Several recent reports pointed out how the practice of using a “second screen” while following a television program is becoming an increasingly widespread phenomenon. When the secondary device is used to read or to comment about a watched program, most of the discussion takes place on popular social media such as Facebook and Twitter. Previous research has shown that the analysis of these contents could lead to a better understanding of the behavior of networked publics and of the structure of the show itself. Nevertheless most of the existing research is focused on the content only and focused on a single episode analysis or on big media events. Leveraging this background, this article presents instead a study focused on the relationships between content and users across an entire airing season of a TV program. Through a quantitative network analysis of the tweets produced during 25 episodes of the Italian political talks show Servizio Pubblico, we identified a small loyal group of viewers. Despite the differences in quantity of content produced, the loyal viewers do not show any sign of forming a community-like structure. We also performed a qualitative analysis of the tweets produced during one specific episode and discussed the elements of the TV show that generated the higher level of engagement on Twitter.     

Performance improvements for search systems using an integrated cache of lists + intersections

Modern information retrieval systems use several levels of caching to speedup computation by exploiting frequent, recent or costly data used in the past. Previous studies show that the use of caching techniques is crucial in search engines, as it helps reducing query response times and processing workloads on search servers. In this work we propose and evaluate a static cache that acts simultaneously as list and intersection cache, offering a more efficient way of handling cache space. We also use a query resolution strategy that takes advantage of the existence of this cache to reorder the query execution sequence. In addition, we propose effective strategies to select the term pairs that should populate the cache. We also represent the data in cache in both raw and compressed forms and evaluate the differences between them using different configurations of cache sizes. The results show that the proposed Integrated Cache outperforms the standard posting lists cache in most of the cases, taking advantage not only of the intersection cache but also the query resolution strategy.