Hull forms of small high-speed wave-piercing monohull crafts and hydrodynamics study

Wave-piercing design is a revolution in hull design for small high-speed boats to operate in adverse sea conditions. To study hydrodynamics of the small high speed wave piercing monohull craft systematically, four typical small high-speed wave-piercing monohull crafts were developed, and validated CFD methods were adopted to calculate hull resistances and motions. The resistances and hull motions of these high-speed wave piercing monohull crafts in calm water and waves were obtained and compared. Obvious operating differences can be observed. High-speed wave piercing monohull crafts with slender and twisted planing hulls have smaller resistance at high speed, but the dynamic effects increase as sea conditions worsen. The high-speed wave-piercing monohull craft with a slim multi-chine hull maintains in waves for softer hull motions but suffers the disadvantages of larger resistance. The high-speed wave piercing monohull craft with a triangular hull shows no obvious advantages compared with the other types.

Rapid assessment of knowledge,attitudes,practices,and risk perception related to the prevention and control of Ebola virus disease in three communities of Sierra Leone

Background:The recent outbreak of the Ebola virus disease(EVD)in Sierra Leone has been characterized by the World Health Organization as one of the most challenging EVD outbreaks to date.The first confirmed case in Sierra Leone was a young woman who was admitted to a government hospital in Kenema following a miscarriage on 24 May 2014.On 5 January 2015,intensified training for an EVD response project was initiated at the medical university of Sierra Leone in Jui.To understand the knowledge,attitudes,practices,and perceived risk of EVD among the public,especially after this training,a rapid assessment was conducted from 10 to 16 March 2015.Methods:Interviews were conducted with 466 participants based on questionnaires that were distributed from 10 to 16 March 2015 by cluster sampling in three adjacent communities,namely Jui,Grafton,and Kossoh Town,in the Western Area Rural District of Sierra Leone.Results:It was found that knowledge about EVD was comprehensive and high.Positive attitude towards prevention was found to be satisfactory.Nearly all participants knew the reporting phone number 117 and had reported some change in behavior since learning about Ebola.More than half(62%)of the participants had a history of travelling to urban areas,which increases the risk of infection.The multivariable logistic regression analysis showed that community and occupation were variables associated with perceived risk of EVD.Conclusions:Our study showed that community level social mobilization and community engagement were an effective strategy in the special context.

A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015

Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical community level measures needed to be explored in the field and tailored to the specific context of communities.Methods:First,community-level education on Ebola virus disease(EVD)prevention was launched for the community’s social mobilizers in six districts in Sierra Leone beginning in November 2014.Then,from January to May of 2015,in three pilot communities,local trained community members were organized to engage in implementation of EVD prevention and transmission interruption measures,by involving them in alert case report,contact tracing,and social mobilization.The epidemiological indicators of transmission interruption in three study communities were evaluated.Results:A total of 6016 community social mobilizers from 185 wards were trained by holding 279 workshops in the six districts,and EVD message reached an estimated 631680 residents.In three pilot communities,72 EVD alert cases were reported,with 70.8%of them detected by trained local community members,and 14 EVD cases were finally identified.Contact tracing detected 64.3%of EVD cases.The median duration of community infectivity for the cases was 1 day.The secondary attack rate was 4.2%,and no third generation of infection was triggered.No health worker was infected,and no unsafe burial and noncompliance to EVD control measures were recorded.The community-based measures were modeled to reduce 77 EVD cases,and the EVD-free goal was achieved four months earlier in study communities than whole country of Sierra Leone.Conclusions: The community-based strategy of social mobilization and community engagement was effective in casedetection and reducing the extent of Ebola transmission in a country with weak health system. The successfullypractical experience to reduce the risk of Ebola transmission in the community with poor resources would potentiallybe helpful for the global community to fight against the EVD and the other diseases in the future.