Unsupervised Frequency Tracking beyond the Nyquist Limit using Markov Chains

This paper deals with the estimation of a sequence of frequencies from a corresponding sequence of signals. This problem arises in fields such as Doppler imaging where its specificity is twofold. First, only short noisy data records are available (typically four sample long) and experimental constraints may cause spectral aliasing so that measurements provide unreliable, ambiguous information. Second, the frequency sequence is smooth. Here, this information is accounted for by a Markov model and application of the Bayes rule yields the a posteriori density. The maximum a postariori is computed by a combination of Viterbi and descent procedures. One of the major features of the method is that it is entirely unsupervised. Adjusting the hyperparameters that balance data-based and prior-based information is done automatically by ML using an EM-based gradient algorithm. We compared the proposed estimate to a reference one and found that it performed better: variance was greatly reduced and tracking was correct, even beyond the Nyquist frequency

Football training program and injury prevention program WTA: a season of analysis with IT management Weakrisk Sporstsolutions in Italan élite football players third division (Serie C).

Purpose: The aim of this study is analyze the relationship with training program and injury prevention program in professional football players during competitive season in AJ Fano Calcio 1906 srl (Italian 3rd Division Serie C, 2019-2020). In fact, it is very important for the team to try to minimize or greatly reduce the incidence of injuries to ensure a better choice of players available to the coach according to the match. Our analysis will try to better understand the importance of creating an adequate postural set up by optimizing the functioning of the muscle kinetic chains, during the pre-training phase. Twenty eigth (n=28) élite football players took part in this study (age 21.4±3.3; body weigth 79.7±3.4 ; heigth 182.4±5.5 ; fat mass 9.2±1.9 ; ), without goalkeepers. In pre-season (4 weeks, from july to august) and during a season (december) the players performed yo yo intermittent recovery test level 2 (IR2), to evaluate aerobic and anaerobic performance before the start of season. At same time the players perfomed jump test (SJ, CMJ, CMJAS, JUMPS 15’’), with Optojump Microgate (Microgate, Bolzano, Italy). Every players has been analyzed with K-GPS Live 50Hz (K-Sport Universal STATS, Montelabbate (PU), Italy) and Polar Team System PRO 2 (Polar Electro, Finland, OY) to recorder maximal heart rate during a intermittent test and official match. Every players has done from July (start preseason) to February (in season), 300 sessions of WTA primitive prevention training program before and after training to preparare muscle chains to daily workout, 244 training during this period. Pre and post training program, performed on a daily basis, highlighted that AJ Fano Calcio 1906 srl, total incidence injury is 3.14/1000h, training incidence injury is 1.34/1000h and match incidence injury is 23.6/1000h, respectively - 23.4% to UEFA data total incidence injury (4.1/1000h), -46.4% to UEFA data training incidence injury (2.5/1000h) and 22.3% to Uefa data match incidence injury (19.3/1000h). Infact, this improvement in match injury (contact and non-contact), probabily due, to difference level of football players: in professional third division there are players that have a reduced coordination and intervention times compared to top level players. This element is clear also in different energy cost (í) from different players level during official matches: first division (21.7±0.7%) vs third division (27±2.5%) (ES=3.05, p<0.05). This event represent energy expenditure during a match: third division has low physical, technical and tactical quality compare first division pro and players have high energy expenditure levels. Probabily our hypothesis on this type of prevention program (primitive WTA) should be used already started youth to prepare muscle chains and improve coordination and movements in future athletes to reduce injuries

Recent Outbursts from the Transient X-Ray Pulsar Cep X-4 (GS 2138+56)

We report on X-ray observations of the 66 s period transient X-ray pulsar Cep X-4 (GS 2138+56) with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO) and with the Rossi X-ray Timing Explorer (RXTE). Two outbursts from Cep X-4 were observed with BATSE in 1993 June-July and 1997 July. Pulse frequencies of 15.0941 +/- 0.0002 mHz on 1993 June 25 (MJD 49,163) and 15.0882 +/- 0.0002 mHz on 1997 July 12 (MJD 50,641) were each measured from 2 day spans of BATSE data near each outburst's peak. Cep X-4 showed an average spin down rate of (-4.14 +/- 0.08)*10^(-14) Hz/s between the 1993 and 1997 outbursts. After BATSE could no longer detect Cep X-4, public observations were performed on 1997 July 18 & 25 with the Proportional Counter Array (PCA) on RXTE. A pulse frequency of 15.088 +/- 0.004 mHz was measured from observations on 1997 July 18 (MJD 50,647). Significant aperiodic noise, with an rms variance of ~18% in the frequency range 0.01-1.0 Hz was observed on both days. Energy and intensity dependent pulse shape variations were also seen in these data. Recently published optical observations associate Cep X-4 with a Be companion star. If all 4 outbursts observed from Cep X-4 are assumed to occur at the same orbital phase, we find that the orbital period is between 23 days and 147.3 days.Comment: 19 pages (LaTeX) including 9 figures. Accepted for publication in the Astrophysical Journa

The global symmetry index, symmetry index, quality index and kinematics of the gait cycle with the synchronized contribution of the latest generation magneticinertial and electromyographic technology. Practical surveys and planning hypotheses for the revision of gesture.

The walk is certainly the cornerstone of human mobility. The literature has focused on the qualitative and quantitative analysis of walking and how certain parameters can change after an aerobic fatigue test. Our research proposal is based, in an innovative way in literature, on the analysis of specific parameters of the gait cycle, considered highly significant, such as the global symmetry index, the symmetry index, the quality index of the gait cycle, pelvic kinematics and muscle activation and the differences in these parameters before and after an aerobic fatigue test (resistance of the gesture over time). A total of 27 male athletes, aged (9-11) participated to the study, in which state-of-the-art equipment was used in the field of movement sciences that includes a device that integrates triaxial inertial sensors and a set of synchronized wireless probes, part of fourth generation instruments, still the most advanced on the market, for wireless surface electromyographic analysis. Thanks to these devices it was possible to carry out an evaluation of the subjects directly, with the live acquisition of data during the entire execution of the test protocol, allowing to evaluate the aforementioned parameters, which are considered strategic in pre-adolescent age, both for a more accurate basic construction of the element sure to offer a better planning of work sessions or training sessions at the time and in the future, also in consideration of periods immediately following high workloads, where fatigue affects the precision of gestures in the young athlete with various consequences, including significant ones, which is not always taken into consideration

Dynamic inertial analysis of the technical boxing gesture of Jab

The purpose of this study is to analyze the inertial dynamics of the Jab technical gesture in boxing. The target is to test and establish with the precision of the latest generation inertial technology the real physical parameters of the mechanical components of the technical gesture subjected to analysis to use, in the event of an expected congruence, the parameters obtained as key elements in the project of sports training investigated for performative purposes, given that the literature on this subject is scarce and sometimes with data obtained using non-state-of-the-art equipment and therefore not reliable. Five boxers (n = 5) took part in this research, considered sufficient for an exploratory study, respectively two female (n = 2), (18.5 ± 6.4 years, weight 63.7 ± 0.4 kg, height 169 ± 1.4 cm; arm length 69.5 ± 2.1 cm) and three male (n = 3), (23.0 ± 3.5 years, weight 80.0 ± 7.0 kg, height 184.3 ± 7.1 cm; arm length 79.7 ± 2.5 cm). These athletes were from different levels of experience, also to obtain specific threshold data in the various stadiums, however, all participating in national level competitions (elitè level). From the dataset, it’s possible to appreciate a different average acceleration value in the Jab execution phase between 8.65 m/s² (woman) and 13.85 m/s² (man) of the stroke, statistically significant (p <0.05), even in the small sample. The same situation is true for the torsion phase of the trunk between the best performing male boxer (boxer 1) and the best female boxer (boxer 5) respectively 0.733 vs 0.338 g² (p <0.05). This allows us to understand how gender and category differences are a key element in relation to the training planning of the discipline and that often turn out to be quite generic and that doesn’t take into account accurately and weighed the differences and what are the values to be respected in the specific training workload and also in the performance level of the exercises necessary to achieve those physiological conditions and techniques useful for performance improvement. The differences in this sample were also evident between individuals of the same gender and level

High glucose-induced hyperosmolarity contributes to COX-2 expression and angiogenesis: Implications for diabetic retinopathy

Background: We tested the hypothesis that glucose-induced hyperosmolarity, occurring in diabetic hyperglycemia, promotes retinal angiogenesis, and that interference with osmolarity signaling ameliorates excessive angiogenesis and retinopathy in vitro and in vivo. Methods and Results: We incubated human aortic (HAECs) and dermal microvascular endothelial cells (HMVECs) with glucose or mannitol for 24 h and tested them for protein levels and in vitro angiogenesis. We used the Ins2 Akita mice as a model of type 1 diabetes to test the in vivo relevance of in vitro observations. Compared to incubations with normal (5 mmol/L) glucose concentrations, cells exposed to both high glucose and high mannitol (at 30.5 or 50.5 mmol/L) increased expression of the water channel aquaporin-1 (AQP1) and cyclooxygenase (COX)-2. This was preceded by increased activity of the osmolarity-sensitive transcription factor Tonicity enhancer binding protein (TonEBP), and enhanced endothelial migration and tubulization in Matrigel, reverted by treatment with AQP1 and TonEBP siRNA. Retinas of Ins2 Akita mice showed increased levels of AQP1 and COX-2, as well as angiogenesis, all reverted by AQP1 siRNA intravitreal injections. Conclusions: Glucose-related hyperosmolarity seems to be able to promote angiogenesis and retinopathy through activation of TonEBP and possibly increasing expression of AQP1 and COX-2. Osmolarity signaling may be a target for therapy

Evaluation of differences at high intensity threshold and its performance value during the most valuable soccer championships in Europe

The sports performance of footballers during games and training has been the subject of research for years. Nowadays thanks to the new technologies applied to the match analysis, is possible to highlightperformance using statistical-mathematical criteria. Recent studies support that not only the phase of the match spent at high speeds are determinants, but even each instant in which the acceleration and deceleration values cross above the high intensity thresholds.Our research seeks essentially to add, in the literature, a specific study, concerning quantity and quality of work expressed on these parameters, above the high intensity thresholds, in the various European elite championships.The search raises 26 players for each match (including substitutes), 260 athletes per championship, for a total of 1300 players (average age 28.4 years, height 1.79 meters, weight kg 78) and 9100 parameters data.The high intensity parameters evaluated are:Distance covered at high intensity (> 16 Km/h); Distance covered in Acceleration (> 2m/s²); Distance covered in Deceleration (< -2m/s²); Distance covered a MP> 20 Watt / Kg; Average AMP; D = Total Distance; Drel = distance/minute. Data shows that the comparison in French league is balanced, that is high intensity activity is equal for winning and losing teams, in German and Italian championship, winning teams work below the high intensity threshold compared with losers, in the English and Spanish league winning teams work upper the high intensity threshold respect to losers. This confirms that the efficiency of sport performance, in case of football the victory of competition or matches, is not directly dependent only on the ability to carry out high-intensity activities and also supports the lack of specific training aimed at promoting the development of such skills. A more specific investigation directed at the analysis of only winning teams and losing teams in all championships showed a no decisive difference in high intensity parameters. In the chart below, it is highlighted that the high intensity activity is greater in the parameters of D_AccHI and D_DecHI in the winning teams than the losers (5-6%)

Validation of the new technology sensor fusion K-50 based on data integration detected by GPS 50 Hz and inertial sensors

Advanced technology systems applied to sports are increasingly valid support for operators and technicians in the sector. Useful to improve the correct planning of training and therefore of the athlete as well as to the correct management of workloads developed during it and of the season. Studies carried out on the use of new dedicated technologies have shown how supportive they are for improving the performance and preparedness of the individual and the athlete in our case, mathematically developing real parameters for the sessions of the sport practiced (Barbero et a., 2010, Boyd et al., 2011, Brodie et al., 2016, Izzo et al., 2018). The attempt is to further reduce the error coefficient, of the same, the GPS in this case, the objective of this validation study is the validity and reliability of the advanced GPS device K-50 (K-Sport Universal, Ita). The test protocol was administered to 50 junior soccer students-players aged 17 ± 3 years by amateur sports clubs in Italy. The athletes were subjected to different types of stresses considered in the literature, significant in surveys with GPS (Izzo et al., 2018). The GPS device K-50 in our case is a tool, also equipped with inertial sensors (IMU) such as accelerometer, magnetometer, gyroscope, and it is the only one on the market that has the features to be able to use the technologies integrated into a calculation method integrated within the K-50 device, thanks to the use of a Sensor Fusion which allows more performing and sharper data quality. The results of the research protocol were compared using different methodologies for the calculation of some investigated parameters or using the GPS device with the Doppler effect, using the Sensor Fusion, and using the position calculation with different interpolations such as Lat-Lon 0.2 and Lat-Lon 0.05 (Latitude - longitude). In the end, the decidedly positive test results verify the validity of the device (GPS K-50). With the use of inertial systems enriched with the Sensor Fusion the error of the device in measuring the distances traveled is very close to zero with a standard deviation within the percentage limits