著者

Masumi Kamata Naohisa Wada Nina Yasuda Daniel Varela Jorge I. Mardones Javier Paredes-Mella Satoshi Nagai

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.18, no.1, pp.55-59, 2023-02-28 (Released:2023-03-02)

参考文献数

35

---

Outbreaks of paralytic shellfish poisoning caused by the toxic dinoflagellate Alexandrium catenella (Dinophyceae) are currently a serious global problem both from economic and food hygiene perspectives. In Chile, A. catenella was first recorded in 1972 and is currently the main harmful algae species in the country, in terms of seafood security. As no relevant microsatellite markers for Chilean A. catenella populations were available, we isolated 23 new polymorphic microsatellite loci of A. catenella from Chile, of which 15 are applicable to both Chilean and Japanese populations. We found a strong genetic break between Chilean and Japanese A. catenella populations (FST=0.298, P<0.001), consistent with the morphological differences between them. In contrast to the Japanese population, for which genetic diversity ranged from 0.268 to 0.937, the Chilean population had a lower genetic diversity, ranging between 0.065 and 0.512. This study successfully developed A. catenella microsatellite markers that can be used to investigate its genetic spatial and temporal bloom diversity and assess further genetic connectivity between the population from southern and northern Chilean areas.

著者

Keita Suzuki Satoshi Nagai Koichi Iwai Ryo Ogaki Takuo Furukawa Masahiro Takemura

出版者

Japan Society of Physical Education, Health and Sport Sciences

雑誌

International Journal of Sport and Health Science (ISSN:13481509)

巻号頁・発行日

pp.201925, (Released:2020-04-06)

参考文献数

31

被引用文献数

2

---

The present study aimed to determine the mechanisms of mild cervical injuries caused by tackling in a rugby union. This study enrolled 137 male players from a Japanese collegiate rugby union club during the 2009–2013 seasons. Twenty-nine (53.7%) of 54 incidents leading to mild cervical injury were identified from match video records and injury data that were reported under the definition of medical attention. In addition, all tackles by players in the same match in which they sustained cervical injury were extracted as a control cohort. All tackles were coded according to eleven characteristics of three tackle phases. Twenty-one tackles were the main events leading to mild cervical injury. The likelihood of tackler-associated mild cervical injuries was significantly higher when tacklers had no time to face forward at the offside line before tackle situations, tackles with incorrect tackler head positions, and not using arms after initial contact. These results suggest that further investigation is needed to determine specific tackling characteristics considering the three tackle phases and their combined effects.

著者

Keita Suzuki Satoshi Nagai Ryo Ogaki Koichi Iwai Takuo Furukawa Shumpei Miyakawa Masahiro Takemura

出版者

The Japanese Society of Physical Fitness and Sports Medicine

雑誌

The Journal of Physical Fitness and Sports Medicine (ISSN:21868131)

巻号頁・発行日

vol.8, no.2, pp.79-88, 2019-03-25 (Released:2019-03-16)

参考文献数

28

被引用文献数

3

---

The purpose of this study was to clarify the tackling characteristics of tacklers relationship causing concussion based on match video records in the collegiate rugby union. Twenty-three tackling situations leading to concussion were identified based on injury data and video records. Additionally, 94 tackling situations in which concussion did not occur were extracted from the same matches. Overall, one hundred and seventeen tackling situations were analyzed in detail, and categorized into three tackle phases and outcomes. Logistic regression analysis was performed to clarify which tackling characteristics in the tackler relationship had a higher chance of concussion. The chance of concussion occurring to a tackler was significantly higher for collision tackle (odds ratio [OR] 84.00, 95% CI 8.27–853.11), making initial contact with tackler’s head/neck (OR 23.47, 95% CI 4.80–114.71), no arm usage by tackler (OR 3.54, 95% CI 1.23–10.20) and tackle break by ball-carrier (OR 5.76, 95% CI 1.67–19.85). Conversely, tacklers were significantly less likely to suffer concussion when the ball-carrier performed a side step before initial contact (OR 0.11, 95% CI 0.01–0.85). In conclusion, tackles leading to concussion were related to various factors in the time period before and after tackle as well as in the moment of tackle. The results of this study suggest that further research needs to be done, given the relationship between each tackling characteristic. Moreover, we consider that players and coaching staff should improve tackle skill safety by clarifying the common contributing factors to both suffering concussion and tackle performance.