World Record Research Articles

Pacing and packing behaviour in elite and world record performances at Berlin marathon

ABSTRACT The aim of this study was to compare pacing and packing behaviours between sex and performance level at elite Berlin marathon races. Official electronic split and finishing times from 279 (149 male and 130 female) marathon performances, including 5 male world records, were obtained from 11 Berlin marathon races held from 2008 to 2018, and from two previous world records and the second world all-time fastest performance also achieved at that same Berlin course. Male performances displaying an even pacing behaviour were significantly faster than those adopting a positive behaviour (p < 0.001; d = 0.75). Male world records were characterized by even profiles with fast endspurts, being especially remarkable at world all-time two fastest performances which were assisted by the use of a new shoe technology. Female marathon runners decreased their speed less than men during the second half marathon and especially from the 35th km onwards (p < 0.001; 0.51 ≤ d ≤ 0.55). The latest race stages were usually run individually in both sexes. Significant pace differences between performance groups at every race segment were found in women (p < 0.01; 1.0 ≤ d ≤ 2.0), who also covered an important part of the race alone. Prior to participation in meet marathon races such as Berlin marathon, elite runners should select the group that they will join during the race according to their current performance level as a preassigned pace set by a pacemaker will be adopted. Therefore, they could follow an even rather than positive pacing behaviour which will allow them to achieve a more optimal performance. Highlights Prior to participation in meet marathon races such as Berlin marathon, elite runners should select the group that they will join during the race according to their current performance level as a preassigned pace set by a pacemaker will be adopted. Athletes could follow an even rather than positive pacing behaviour which will allow them to achieve a more optimal performance. Female runners should consider being paced by a male runner of greater performance level as runners of both sexes are allowed to run the race altogether during this type of races.

Kinematic and dynamic analyses of the front crawl tumble turn in elite female swimmers

Based on a three-dimensional (3D) underwater analysis, the objective of the present study was to identify the biomechanical variables the most associated with turn times in 10 elite female swimmers. For each participant (95.7 ± 2.6% of the 200 m freestyle world record), the best-time turn (from 3 m in to 3 m out, 2.89 ± 0.08 s) was analysed from a three-dimensional (3D) direct linear transformation kinematical reconstruction and the use of a piezoelectric force platform. Bivariate analysis showed that lateral impulse was linked to turn time (r = -0.76, p = 0.01) as well as horizontal velocities at end of the glide and swim resumption (respectively, 1.88 ± 0.2 m·s−1 and 1.48 ± 0.15 m·s−1; r = -0.67 and -0.68; p < 0.05 for both variables). One variable was considered relevant in the best Lasso (Least Absolute Shrinkage and Selection Operator) model: the lateral impulse (8.8 ± 5.1 N·s) during the placement sub-phase.The best tumble turn times were associated with higher lateral impulse during the placement and faster velocities during the underwater actions. The lateral impulse may reflect the swimmers’ longitudinal rotation which was higher for the fastest swimmers.

Trophies, Technology, and Timescape in Fisheries Management, as Exemplified through Oklahoma's World Record Paddlefish Polyodon spathula

In this paper, we use world record Paddlefish Polyodon spathula catches to exemplify the origins and management of trophy fisheries and the human motivations involved within a continually compressing timescape of advancing fish finding, harvest capability, and communication and information technologies. Conservation of long‐lived species such as Paddlefish, sturgeons (Acipenseridae), or other large species currently challenged by ecological change or habitat losses may be further challenged by the expansion of harvest power through advances in fishing technology in pursuit of trophy fish. Technological evolution may outpace the adaptive abilities of managers to safeguard these fisheries with sensible harvest regulations—often a multi‐year, bureaucratic process. Managers must maintain focus on understanding the ecological nuances of these species while proactively developing resilient harvest management frameworks capable of responding to such challenges in a meaningful and timely way. Our paper may be useful for other fisheries professionals involved in management of long‐lived, trophy fishes and fisheries.

Relationships Between Performance and Injury Occurrence in Athletics (Track and Field): A Pilot Study on 8 National-Level Athletes From Sprints, Jumps and Combined Events Followed During at Least Five Consecutive Seasons.

BackgroundPerformance success or failure in athletics (Track and Field) and the capacity to succeed are driven at the adult level, like in other sports, by many factors, injury being one of them. More information regarding the potential relationships between performance and injuries in athletics is needed.ObjectiveTo analyse the potential association between performance and occurrence of injuries in national-level athletics athletes from sprints, jumps and combined events through several seasons.MethodsWe performed a retrospective analysis of performance and injury data collected prospectively in 8 national-level athletics athletes followed during at least five consecutive seasons from 2009 to 2019. For each athlete, injuries data [total injuries (injuries) and time-loss injuries (TLI)] were collected by the same sports medicine physician throughout the study period using a medical attention injury definition. Performances during official competitions were collected on the French Federation of Athletics website, and included (i) any participation in national championships, (ii) any participation in an international competition (i.e., being national team member for an international competition), (iii) any podium at the national championships, (iv) any podium at an international competition, and (v) performance metrics normalised to the world record (WR) of the respective athletics speciality (%WR). For each athlete, we performed a descriptive analysis of the performances and injuries. We also performed four binomial logistic regressions with (1) national championships participation (yes/no) or (2) international competition participation (yes/no) as dependent variables, and injuries (yes/no) or TLI (yes/no) as independent variables, adjusted for individual athlete and number of seasons, and in models on participation in international competitions, was also adjusted for national championship participation (yes/no), with Odd Ratios (OR) with 95% confidence intervals (95%CI).ResultsAmong the 8 national-level athletics athletes included in the present study, cumulated 155 injuries, including 52 TLI (33.5%). There was an average of 2.7 ± 1.7 injuries and 0.9 ± 0.6 TLI per athlete per season over the study period. The occurrence of injuries was significantly associated with higher odds of national championships participation (OR = 4.85 [95% CI 3.10 to 3050.5], p = 0.021). The occurrence of TLI was significantly associated with higher odds of national championships participation (OR = 133.6 [95% CI 4.92 to 14251.5], p = 0.013). The occurrence of injuries or TLI were associated with insignificantly lower odds of international championships participation.ConclusionsOur present pilot study confirms that injuries are part of an athletes' life. The occurrence of at least one injury was associated with higher odds of participation in a national championship, whereas the absence of at least one injury was associated with higher odds of participation in an international championship. We hypothesised that the length of the season can play a role in the risk of injury occurrence, but if the athlete wants to reach his/her highest level, decreasing the risk of injuries seems to be of importance. Despite the caution that should be taken in the interpretation of our results, our present study confirms the interest and relevance of injury risk reduction approach in athletics.

EP News: Case Reports

In 1960 the first self-powered pacemaker was implanted in a patient. Since that time, the technology has matured and evolved into a common medical therapy used worldwide to treat bradyarrhythmias. McIlraith and Crozier (https://doi.org/10.1016/j.hrcr.2022.02.005) shared what may be the world record of a patient who required continuous permanent pacing. The patient was a 36-year-old man who presented with syncope in second-degree heart block type II with a heart rate of 45 beats/min. In 1969 he received a nonprogrammable mercury-zinc battery powered Teletronics P6 pacemaker with a unipolar lead implanted through the right external jugular vein.

A review of giants: Examining the species identities of the world's heaviest extant bony fishes (ocean sunfishes, family Molidae).

The world's heaviest extant bony fish has long been considered the ocean sunfish Mola mola (family Molidae). However, recent taxonomic research suggests the world record specimen (2300 kg) was actually a misidentified giant sunfish M. alexandrini. Moreover, the history of taxonomic confusion in the genus Mola, combined with anecdotal size information perpetuated in both media and literature, has resulted in uncertainty in regard to species identity and actual weights of very large Mola specimens. In this study, we searched for records of molid specimens with reported body mass over 2000 kg, with a focus on the north-west and south-west Pacific. For each specimen, we reviewed the species identification and assessed the reliability of the information, including if the specimen had actually been weighed. Of the 15 specimens uncovered, we identified one M. mola and 14 M. alexandrini, and found that only five had actually been weighed (one with the viscera removed). Furthermore, we collected length-weight data for verified M. alexandrini specimens from the literature and museum specimens, and established the first length-weight relationship for this species [body mass (kg)=1.1 × 10-5 × total length (cm)3.3248 (29-330 cm total length, n=20)]. These findings are discussed in the context of other extant bony fish species, which allegedly also exceed 2000 kg in body mass, i.e., other Molidae species and the beluga sturgeon Huso huso. Overall, we conclude that M. alexandrini is the only extant bony fish species we could confirm that exceeds 2000 kg, and that basic biological information is generally not collected when very large molid specimens occasionally are stranded or are caught. Finally, we confirm that the world's heaviest extant bony fish specimen actually weighed was a female M. alexandrini (2300 kg, 272 cm total length) captured from Kamogawa, Chiba Prefecture, Japan, on August 16, 1996.

On the Road to Camarón: The Sleep of an Ultra-Endurance Athlete Cycling 10,000 km in 24 Days

The impact of sleep on performance is fundamental for ultra-endurance athletes, but studies on this issue are rare. The current investigation examined the sleep and performance of a cyclist engaged in a simulated 10,000 km tour. The sleep behavior of the athlete (age, 57; height, 1.85 m; mass, 81 kg) before, during (i.e., 23 nights), and after the tour was monitored using a reduced-montage dry-electroencephalographic (EEG) device. The daily performance (i.e., number of kms) was recorded throughout the race. The cyclist set a new world record, completing 10,358 km in 24 days with a mean daily distance of ≈432 km in approximately 16 h, i.e., an average speed of ≈27 km/h. Sleep duration throughout the tour (5:13 ± 0:30) was reduced compared to the baseline sleep duration (7:00 ± 1:00), with a very large difference (ES = 2.3). The proportion of N3 during the tour (46 ± 7%) was compared to the measured N3 proportion during the baseline (27 ± 5%) and was found to be systematically outside the intra-individual variability (mean ± 1 SD), with a very large difference (ES = 3.1). This ultra-endurance event had a major influence on sleep-duration reduction and a notable modification in sleep architecture. The increase in slow-wave sleep during the race may be linked to the role of slow-wave sleep in physiological recovery.

LVADs: The Western Australian Experience

<h3>Purpose</h3> Review outcomes of the Western Australian (WA) LVAD program. <h3>Methods</h3> Retrospective review of medical records and local databases. <h3>Results</h3> In 23 years, 140 LVADs (no RVAD/BIVADs) have been inserted in WA: 46 HeartWare HVAD (HW), 26 HeartMate III (HM3), 16 HeartMate II (HM2), and 52 earlier generation devices. Abstract data refers to HW/HM2/HM3. Insertion indications were non-ischaemic cardiomyopathy (60%) and ischaemic (40%). 89% were inotrope dependant pre-implant, with median LV ejection fraction 20%. 34% had severe right ventricular (RV) dysfunction on echo, and on right heart catheterisation median cardiac index was 1.7L/min/m². We aggressively and pre-emptively manage for RV failure (RVF): early RVF (requirement for inotropes >14 days) occurred in only 7% and no patients required RVAD. 64% received ≥5 days of early inhaled pulmonary vasodilators, and 88% were discharged on sildenafil (median daily dose 150mg). Median ICU length of stay (LOS) was 2 days. 95% of patients survived to hospital discharge (median LOS 23 days). Following discharge, median percentage of days with LVAD spent as an outpatient was 98%, and median number of hospital readmissions was 1.8 per patient years. LVAD-associated infection requiring admission or intravenous antibiotics occurred in 36%, gastrointestinal bleeding in 16%, and stroke in 11%. The percentage of patients alive with LVAD at 1, 2, and 5 years was 93%, 87%, and 63%, respectively, which betters current international INTERMACS survival. 93% of patients were implanted as bridge-to-transplant/candidacy, with median transplant wait time 9 months. Of our six destination therapy patients there have been no deaths before 5 years, and our centre holds the world record for the 2 longest surviving HW patients at 11.3 and 10.5 years. All aspects of VAD management including anticoagulation and driveline care are performed exclusively by our service in Perth (the nearest VAD centre is 1700 miles away). <h3>Conclusion</h3> Excellent outcomes can be achieved with single-centre care despite geographical isolation.

Paralympians Are Stronger Than You Know: A Comparison of Para and Nondisabled Powerlifting Bench Press World Records.

van den Hoek, D, Garrett, J, Howells, R, and Latella, C. Paralympians are stronger than you know: A comparison of para and nondisabled powerlifting bench press world records. J Strength Cond Res 37(2): 452-456, 2023-This investigation explored the absolute and relative strength of bench press world record holders for World Para Powerlifting (WPPO) and International Powerlifting Federation (IPF) athletes. Athlete data (mass [in kilograms], competitive weight class, and bench press mass [in kilograms]) for world record holding male and female athletes were extracted from public databases. Absolute and relative strength (kg·kg bw-1 ) of athletes was compared using IPF competitive weight classes. On an individual basis, WPPO world record holders demonstrated greater absolute strength than their IPF counterparts in 5 of 8 weight classes for women and 6 of 8 weight classes for men when classified using standard IPF competitive weight classes. Overall, effect sizes for relative strength were greater in WPPO male (19.6%, g = 0.75) and female (9.24%, g = 0.38) athletes but did not reach statistical significance. The greatest relative strength observed was 3.88 kg·kg bw-1 (under 49-kg WPPO) for male and 2.72 kg·kg bw-1 (under 50-kg WPPO class) for female athletes. For IPF athletes, the greatest relative strength was reported in the under 66-kg class for male athletes (3.35 kg·kg bw-1 ) and under 63-kg class for female athletes (2.29 kg·kg bw-1 ). The physical impairments experienced by WPPO world record holders do not appear to compromise bench press strength compared with able-bodied athletes. Indeed, WPPO world record holders often possess greater relative and absolute strength than their IPF counterparts. Superior para powerlifting bench press records may be, at least in part, the result of training and biomechanical factors and seem to be the only anaerobic strength-based sport where para records exceed that of able-bodied athletes.

Oral Diseases and Oral Health-Related Quality of Life among Kenyan Children and Adolescents with HIV.

Children and adolescents living with HIV (CALHIV) have a higher risk of hard and soft oral tissue diseases as compared with their healthy peers. It is important to increase awareness regarding the need to integrate oral health within medical care among pediatric HIV populations. Studies on associations of oral diseases with oral health-related quality of life (OHRQoL) in CALHIV are lacking. This study examined the association between oral diseases and OHRQoL in Kenyan CALHIV. This cross-sectional analysis was nested in a longitudinal cohort study of CALHIV in Nairobi. CALHIV received oral examinations, and the World Health Organization's Oral Health Surveys and Record Form was administered. OHRQoL was measured with the Parental-Caregiver Perceptions Questionnaire, with the subdomains of global, oral symptoms, function limitations, and emotional and social well-being, with higher scores indicating poorer OHRQoL. Linear regression was used to model associations between OHRQoL and oral diseases, adjusting for age at the time of oral examination, CD4 counts, and caregiver's education. Among 71 CALHIV, the mean age was 12.6 y (SD, 2.9; range, 10 to <21), and the mean composite OHRQoL score was 12.6 (SD, 11.2). Ulcers (not herpes simplex virus or aphthous) were associated with the worst overall OHRQoL (mean, 21.8; SD, 11.1; P = 0.055) and oral symptoms subdomain (mean, 7.0, SD, 2.5; P = 0.003). Children with dry mouth and untreated caries had significantly higher mean global OHRQoL scores than those without disease (P < 0.0001). In the multivariate analysis, the OHRQoL composite score was 6.3 units (95% CI, -0.3 to 12.9) higher for those who had dry mouth and untreated dental caries; dry mouth accounted for the highest percentage of variability of OHRQoL (9.6%) and the global subdomain (31.9%). Ulcers accounted for the highest percentage of variability of the oral symptoms domain (15.4%). Oral ulcers, dry mouth, and untreated caries were associated with poorer OHRQoL in CALHIV. Integrating oral health into the primary care of CALHIV may improve their OHRQoL. This study aimed to determine the association of oral diseases with the oral health-related quality of life of children and adolescents living with HIV (CALHIV). The findings will form part of the evidence to incorporate oral health protocols into care programs for CALHIV. Oral health monitoring has the potential to increase the surveillance of HIV clinical status, monitor the effectiveness of antiretroviral therapy, and improve the oral health-related quality of life of CALHIV.

Electromagneto-mechanical model of high temperature superconductor insert magnets in ultra high magnetic fields

Second-generation high-temperature superconducting (2G HTS) tapes are considered to be the main candidates for the development of future ultra-high DC magnetic field magnets. In such applications, the usability of the HTS magnets can be strongly impaired by large screening currents developed in the flat strip of the tapes. These currents lead to the generation of a screening current-induced field (SCIF) that can deteriorate the performance by affecting the stability and the homogeneity of the magnetic field. Besides the SCIF, there is also the likely mechanical degradation of the tapes under the action of large Lorentz forces. The mechanical degradation and the presence of large screening currents intertwine to affect the reliable operation of 2G HTS magnets. To study the combined issues, an electromagneto-mechanical model based on tensile mechanical characterization of short samples was built to simulate the coupled electromagnetic and mechanical behaviors of insert magnets made of 2G HTS tapes under very high magnetic field. The coupling is carried out by considering the dependence of the n index and the critical current density on the local relative deformation in addition to the magnetic flux density. The case study is the Little Big Coil (LBC, version 3) which broke the world record of the strongest continuous magnetic field achieved to this date. An analysis of the electromagneto-mechanical behavior of the LBC is conducted on the basis of information extracted from the literature to show that the proposed model can assess the current magnitude at which the insert magnet quenched. Additionally, it is shown that the model can also provide some insights on the impact of the mechanical degradation of the tape on the SCIF hysteresis loop. The studies are conducted on the original LBC and on versions that include additional modifications such as harnessing and co-winding with rigid metallic tapes. These modifications are employed to limit the mechanical degradation of the HTS insert magnet under ultra-high magnetic field. They are expected to deliver an extra safety margin to 2G HTS insert magnets.

Influence of advanced footwear technology on sub-2 hour marathon and other top running performances

Abstract In 2019, Eliud Kipchoge ran a sub-two hour marathon wearing Nike’s Alphafly shoes. Despite being the fastest marathon time ever recorded, it wasn’t officially recognized as race conditions were tightly controlled to maximize his success. Besides, Kipchoge’s use of Alphafly shoes was controversial, with some experts claiming that they might have provided an unfair competitive advantage. In this work, we assess the potential influence of advanced footwear technology and the likelihood of a sub-two hour marathon in official races, by studying the evolution of running top performances from 2001 to 2019 for long distances ranging from 10 km to marathon. The analysis is performed using extreme value theory, a field of statistics dealing with analysis of rare events. We find a significant evidence of performance-enhancement effect with a 10% increase of the probability that a new world record for marathon-men discipline is set in 2021. However, results suggest that achieving a sub-two hour marathon in an official race in 2021 is still very unlikely, and exceeds 10% probability only by 2025.

China's Experimental Advanced Superconducting Tokamak sets new world record

China's Experimental Advanced Superconducting Tokamak (EAST), as shown in Figure 1, in the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) made an important advance by achieving a stable 1056 seconds steady-state high-temperature plasma operation, setting a record long-pulse operation on the night of December 30,2021, as shown in Figure 2. This result marks that EAST became the first tokamak that can operate with a pulse length in thousand-second scale.

Silicon heterojunction solar cells: Techno-economic assessment and opportunities

<h2>Summary</h2> The ever-increasing electricity demand from renewables has stimulated growth in the photovoltaic (PV) industry. Yet, while grid parity has already been achieved in several countries, a continued decline in module prices coupled with further efficiency improvements at an annual growth rate of ∼0.5%_abs are needed to sustain its market growth. Mainstream PV technologies are still based on crystalline silicon (c-Si) wafers with heavily doped regions and directly metallized contacts. However, these cause band-gap narrowing, Auger recombination losses, and contact recombination losses. Passivating contact (PC) technologies can overcome these limitations by decoupling surface passivation and contact formation requirements. Among PC technologies, amorphous silicon-based silicon heterojunction (SHJ) solar cells have established the world record power conversion efficiency for single-junction c-Si PV. Due to their excellent performance and simple design, they are also the preferred bottom cell technology for perovskite/silicon tandems. Nevertheless, SHJ technology accounts for only ∼2% of the current PV market share. In this review, we discuss the techno-economic challenges for large-volume SHJ manufacturing. In doing so, we highlight critical areas that need to be addressed for enabling terawatt-scale SHJ deployment.

The impact of Ga and S concentration and gradient in Cu(In,Ga)(Se,S)2 solar cells

As one of the leading photovoltaic materials, Cu(In,Ga)(Se,S)2 has two distinct advantages over other candidates. First, its conduction band and valence band could be independently tuned by adjusting the Ga/(Ga + In) and S/(S + Se), respectively. Next, its composition distribution could be feasibly tuned by controlling the thin film deposition process. These merits have been utilized in fabricating the Cu(In,Ga)(Se,S)2 solar cells with world record efficiency. However, these features have not yet been satisfactorily simulated. In order to understand the mechanism of high-performance Cu(In,Ga)(Se,S)2 solar cells, we obtained the tunable bandgap of absorber layer and suitable conduction band offset between absorber layer and buffer layer via Ga and S concentration and gradient, by combining both first-principle calculations and numerical simulations with Poisson equation and the continuity equation. In particular, compared with other photovoltaic materials, the bandgap of Cu(In,Ga)(Se,S)2 could be tuned flexibly across the layer thickness to realize spatial energy band optimization with double-concentration-grading absorber. The efficiency of 23.29% was obtained based on theoretical calculations and numerical simulations, which is almost the same as the reported result, in the considerations of (i) optimum bandgap of absorber, (ii) band energy offset, (iii) double (Ga- and S-) concentration grading, and (iv) low defect density in the absorber layer. In addition, we obtained a Cu(In,Ga)(Se,S)2 solar cell with a high S content uniform band gap efficiency of 23.53%. Therefore, we provided an understanding for tunable engineered band energy research in high-efficient Cu(In,Ga)(Se,S)2 solar cells.

Ultraviolet Photocatalytic Degradation of Perovskite Solar Cells: Progress, Challenges, and Strategies

The certified efficiency of perovskite solar cells (PSCs) has reached 25.5% within just around 10 years, approaching the highest reported value of mainstream silicon solar cells. The application of metal–oxide (MO) electron transport layers (ETLs), including TiO2 and SnO2, is crucial for achieving highly efficient PSCs because of their wonderful photoelectrical properties, resulting in n–i–p conventional structure devices, constantly breaking the world record efficiency. However, these MOETLs inevitably lead to the degradation of PSCs due to their photocatalytic activity under actual sunlight which includes ultraviolet (UV) range. Overcoming the UV photocatalytic degradation is still a great challenge for the state‐of‐the‐art PSCs toward practical applications. Herein, the recent progress related to the UV photocatalytic degradation of PSCs induced by the MOETLs based on recent literature reports is reviewed, including the photocatalysis origin, degradation mechanism, challenges, and various strategies. Perspectives for future efforts in overcoming UV photocatalytic degradation are provided. It is believed that this review is advantageous for achieving stable PSCs under actual outdoor sunlight.

The COVID-19 pandemic impact on the best performers in athletics and swimming among paralympic and non-disabled athletes.

The COVID 19 pandemic has greatly disrupted high performance sport and international competition. The aim of this study was to quantify the impact of the COVID-19 pandemic on the world's top 10 performances in Athletics and Swimming among non-disabled and Paralympic athletes. The results of the 10-best world performers in 66 Olympic events since 1891 and 255 Paralympic events since 2010 were collected. To quantify the performance trend, the slopes of the 4 years moving average were calculated and analyzed by time period. The distribution of performances (in % of the world record) by year was analyzed to compare the 2020 values to the ten previous years. The stability rate (athletes joining and leaving each year) since 2010 and the number of annual competitions events were also measured. Over the study period, such declines in performance have only been observed during the two World Wars. In 2020, the level of performances has decreased significantly, corresponding to a 6 to 10 years setback. In 2020, the number of new athletes in the 10-best was significantly higher with a lower number of organized competitions. The impact on the performances of the best international non-disabled and Para athletes has been considerable.

Efficient computation of permanents, with applications to Boson sampling and random matrices

In order to find the outcome probabilities of quantum mechanical systems like the optical networks underlying Boson sampling, it is necessary to be able to compute the permanents of unitary matrices, a computationally hard task. Here we first discuss how to compute the permanent efficiently on a parallel computer, followed by algorithms which provide an exponential speed-up for sparse matrices and linear run times for matrices of limited bandwidth. The parallel algorithm has been implemented in a freely available software package, also available in an efficient serial version. As part of the timing runs for this package we set a new world record for the matrix order on which a permanent has been computed.Next we perform a simulation study of several conjectures regarding the distribution of the permanent for random matrices. Here we focus on permanent anti-concentration conjecture, which has been used to find the classical computational complexity of Boson sampling. We find a good agreement with the basic versions of these conjectures, and based on our data we propose refined versions of some of them. For small systems we also find noticeable deviations from a proposed strengthening of a bound for the number of photons in a Boson sampling system.

Optimized Energy Management Strategy for Hybrid Fuel Cell Powered Drones in Persistent Missions using Real Flight Test Data

AbstractThis paper proposes an optimized energy management strategy (EMS) for hybrid electric fuel cell/battery-based drones focusing on fuel economy while extending sources lifespans in persistent missions. An off-the-shelf drone fed by a 650W fuel cell is selected as a case study, where the power splitting is conventionally managed by a simple rule-based method. Then, a multi-objective genetic algorithm is used to optimize the proposed EMS parameters considering three scenarios regarding battery state of charge, namely charge sustaining, depleting, and increasing. Therefore, advantages of rule-based strategy and genetic algorithm are combined in an online EMS to fit on drone applications. Extensive simulation results demonstrate that the proposed approach allows power sources to operate within their rated area, prolonging their service life, and leading to 5.1% of fuel consumption reduction. Thus, the autonomy will be increased depending on the carried hydrogen quantity, and the world record can be extended by about 37min. It may also lead to benefit in the operating cost achieving 1450C during one fuel cell stack lifecycle. In fleet tasks, the benefit can be further multiplied.

Cashless Travelers from China, Is Tanzanian Tourism Industry Ready? A Review on Tourism Transactions in Connection with Post-COVID-19 Pandemic Tourism World

Cashless transactions also known as mobile payments have been a huge form of money exchange that replaced the use of cash and credit cards especially on COVID-19 pandemic period in different parts of the world. It broke world record for China making it the first cashless most user nation. Exchanges are done via devices like phones, tablets and the like. In order to cope with tourism transactions dynamics that truly affects the industry such abrupt changes forces tourist destinations like Tanzania to adapt. Using a qualitative approach the study examines on literatures pertaining to increased use of cashless transactions especially after COVID-19 pandemic. Results show that though Tanzania is one of the fast cashless transactions users in Africa it is not well prepared to host cashless travelers from China. It has not yet incorporated the giant Chinese cashless transactions platforms and still uses cash and cards in most of tourism financial transactions. With the huge shift of form of Chinese transaction behavior which has created a cashless society in China, the study advice African destinations on the importance of incorporating Chinese cashless platforms to be competent in attracting more tourists from that giant source market.