Why the dominance of East Africans in distance running?A narrative review

Introduction:Runners from East Africa including Kenya,Ethiopia and Uganda have dominated middle-and longdistance running events,for almost six decades.This narrative review examines and updates current understanding of the factors explaining the dominance of East Africans in distance running from a holistic perspective.Content:The dominance of East African distance runners has puzzled researchers,with various factors proposed to explain their unparalleled success.Four key elements emerge:1)biomechanical and physiological attributes,2)training characteristics,3)psychological motivations,and 4)African diet.Runners from East Africa often exhibit ectomorphic somatotypes,characterized by lean body compositions which lead them to an extraordinary biomechanical and metabolic effciency.Their sociocultural lifestyle,training regimens beginning at a young age with aerobic activities,seem crucial,as well as moderate volume,high-intensity workouts at altitudes ranging from 2,000 to 3,000 m.Psychological factors,including a strong motivation to succeed driven by aspirations for socioeconomic improvement and a rich tradition of running excellence,also contribute significantly.A multifactorial explanation considering these factors,without a clear genetic influence,is nowadays the strongest argument to explain the East African phenomenon.Summary and outlook:To unravel the mystery behind the supremacy of East African runners,it is imperative to consider these multifaceted factors.The predominantly rural lifestyle of the East African population underscores the importance of aligning modern lifestyles with the evolutionary past of Homo sapiens,where physical activity was integral to daily life.Further research is required to explain this phenomenon,with a focus on genetics.

The Introduction of Biofuels in Marine Sector

Sulphur and emissions related limits which are imposed on marine fuels drive the maritime industry to look on alternative fuels. The maximum sulphur content of the fuel has already decreased in the ECAs SOx （Sulphur Emission Control Areas） from 1.5% to 1% from 1 July, 2010, and to 0.1% from 1 January, 2015. Globally, the highest permitted sulphur content of fuel will be reduced, as from 1 January, 2020 to 0.5%. Increasing demand of low sulphur fuel is anticipated, leading to a substantial mitigation of marine fuels from residual to distillate ones. Biodiesel or else FAME （Fatty Acid Methyl Esters） and mixtures of it with conventional petroleum fuels, constitute alternative energy source for the maritime industry. The International Standard EN （European Norme） ISO （International Organization for Standardization） 8217 specifies the requirements of petroleum fuels for use in marine diesel engines. According to the previous version of EN ISO 8217：2012, distillate fuels should comply with the ＂de minimis level＂ of approximately 0.1% v/v FAME. Nevertheless, with the latest revision of EN ISO 8217 standard in 2017, the incorporation of FAME up to 7% v/v is allowed in specific marine distillate grades as DF （Distillate FAME） grades. Marine distillates can also include hydrocarbons from synthetic or renewable sources, similar to the composition of petroleum distillate fuels.

An X-Band Low Noise Amplifier Design for Marine Navigation Radars

In this paper, the design of a 9.1 GHz Low Noise Amplifier (LNA) of a RADAR receiver that is used in the Navy is presented. For the design of the LNA, we used GaAs Field-Effect Transistors (FETs) from Agilent ADS component library. In order to keep the cost of the circuit in low prices and the performance high, we design a two-stage LNA.

Proclus＇ Ontological Arguments concerning the Objective Existence of the Forms

In his commentary on the Platonic Parmenides, the Neoplatonist philosopher Proclus （ca. 411-485） offers a systematic defense of the objective existence of the Forms by means of the use of distinctive arguments, four of which are ontological. In contrast with Aristotle, Proclus clearly accepts that the Forms exist as principles of the world and not as posterior concepts describing the common elements of the sensible entities. Thus, he argues first that the ontological presuppositions of the sensible beings are placed in the area of the self-subsistent beings, which correspond to the categories of the Second Hypothesis of the Parmenides. The Forms belong to this area as well. In this respect, Proclus refers to the way of production of the sensible beings, aiming at a strict definition of this process. Secondly, he proves that the existence of the Forms, which possess ontological completeness, is prior to the existence of the sensible things. This is possible since the Forms are generated by the Demiurge of the whole world, by means of an internal reflection upon himself. Thirdly, in order to prove that the sensible world cannot be attributed to mere chance, he argues that the external activity, i.e., the creation of the world, depends on the internal activity, i.e., the development of the Forms in the divine intellect. Fourthly, he implements the concept of hierarchy in the realm of the Forms, through an extensive reference to the ontological priority of the imparticipable over the participable. Thus, he shows how the existence of the primary and intelligible Forms is prior to that of the substantiated Forms. Interestingly enough, the above-mentioned arguments exercised considerable influence on the commentaries of the members of the school of Ammonius, son of Hermias.

Pre/Post Assessments Analysis in Training Electro-Technical Seafarers Experts

In maritime industry, personnel’s training is considered by shipping companies as a top priority matter on the list of factors affecting competitiveness in operating vessels. This paper presents the importance and the effects of training Electro-Technical Experts in the context of latest developments, particularly the advent of the “Electric Ship” and the “Communicative Ship” analyzing the feedback received from several relevant two-days seminars for “Ship Electrical and Electronic Systems for Electro-Technical Officers”, in North East European countries. The pre-test and post-test self assessment method that has been used for more efficient interaction between trainers and trainees is analyzed using t-statistics. The attendees have had diverse basic backgrounds, yet company experts Fleet Engineers on merchant or war ships. The training’s effectiveness and gain is discussed in this paper and further proposals for the Electrical and Electronic training are presented through the valuable feedback for improvement.

Assessing core body temperature in a cool marathon using two pill ingestion strategies

Objectives The purpose was to directly assess in-competition thermoregulatory responses in recreational runners during a city marathon conducted in cool,ambient conditions using a two-pill ingestion strategy.Methods Thirty-two recreational runners(age:38.7±10.2 years,mass:73.9±11.0 kg,height:177±8 cm)were invited to participate in this study.Core temperature was continuously assessed using telemetric ingestible pills.Each runner swallowed two pills:the first pill(Pill 1)11 h:47 min±1 h:01 min pre-race(before overnight sleep)and the second(Pill 2)2 h:35 min±0 h:54 min pre-race(on wakening).Results Pre-race core temperature for Pill 1 was significantly different from Pill 2,with values of 37.4±0.4℃and 37.1±0.6℃,respectively(p=0.006).The mean core temperature during the race was higher for Pill 1 compared to Pill 2(38.5±0.5℃and 37.8±1.0℃,respectively;p<0.001).Peak core temperature was higher for Pill 1 compared to Pill 2(39.1±0.5℃and 38.8±0.5℃,respectively;p=0.03).Post-race core temperature was higher for Pill 1 compared to Pill 2(38.8±0.7℃and 38.1±1.3℃,respectively;p=0.02).Conclusions The timing of pill ingestion significantly impacted core temperature and hence timing of pill ingestion should be standardised(5 h:30 min–7 h prior to measurement).Despite the relatively cool ambient conditions during the race,a significant number of runners achieved a high core body temperature(≥39℃),which was not accompanied by any signs of heat illness.

Effect of dicarboxylic acid esters on the lubricity of aviation kerosene for use in CI engines

To reduce their fuel related logistic burden,North Atlantic Treaty Organization(NATO)Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment.To this end,F-34(the commercial equivalent is Jet A-1)is replacing distillate diesel fuel in many applications.However,tests conducted with this kerosene type on high frequency reciprocating rig showed that this type of fuel causes unacceptable wear.This excessive wear is caused by the poor lubricity of aviation fuel.In order to make this type of fuel compatible with direct injection compression engines,seven di-carboxylic acid esters have tested to improve the lubricity of kerosene.Tribological results showed that all esters tested in this series of experiments seem to be suitable for increasing the kerosene lubricity to a satisfactory level.