165 research outputs found
Viruses of Fish: An Overview of Significant Pathogens
The growing global demand for seafood together with the limited capacity of the wild-capture sector to meet this demand has seen the aquaculture industry continue to grow around the world. A vast array of aquatic animal species is farmed in high density in freshwater, brackish and marine systems where they are exposed to new environments and potentially new diseases. On-farm stresses may compromise their ability to combat infection, and farming practices facilitate rapid transmission of disease. Viral pathogens, whether they have been established for decades or whether they are newly emerging as disease threats, are particularly challenging since there are few, if any, efficacious treatments, and the development of effective viral vaccines for delivery in aquatic systems remains elusive. Here, we review a few of the more significant viral pathogens of finfish, including aquabirnaviruses and infectious hematopoietic necrosis virus which have been known since the first half of the 20th century, and more recent viral pathogens, for example betanodaviruses, that have emerged as aquaculture has undergone a dramatic expansion in the past few decades
Time Critical Social Mobilization: The DARPA Network Challenge Winning Strategy
It is now commonplace to see the Web as a platform that can harness the
collective abilities of large numbers of people to accomplish tasks with
unprecedented speed, accuracy and scale. To push this idea to its limit, DARPA
launched its Network Challenge, which aimed to "explore the roles the Internet
and social networking play in the timely communication, wide-area
team-building, and urgent mobilization required to solve broad-scope,
time-critical problems." The challenge required teams to provide coordinates of
ten red weather balloons placed at different locations in the continental
United States. This large-scale mobilization required the ability to spread
information about the tasks widely and quickly, and to incentivize individuals
to act. We report on the winning team's strategy, which utilized a novel
recursive incentive mechanism to find all balloons in under nine hours. We
analyze the theoretical properties of the mechanism, and present data about its
performance in the challenge.Comment: 25 pages, 6 figure
Overlapping and Robust Edge-Colored Clustering in Hypergraphs
A recent trend in data mining has explored (hyper)graph clustering algorithms
for data with categorical relationship types. Such algorithms have applications
in the analysis of social, co-authorship, and protein interaction networks, to
name a few. Many such applications naturally have some overlap between
clusters, a nuance which is missing from current combinatorial models.
Additionally, existing models lack a mechanism for handling noise in datasets.
We address these concerns by generalizing Edge-Colored Clustering, a recent
framework for categorical clustering of hypergraphs. Our generalizations allow
for a budgeted number of either (a) overlapping cluster assignments or (b) node
deletions. For each new model we present a greedy algorithm which approximately
minimizes an edge mistake objective, as well as bicriteria approximations where
the second approximation factor is on the budget. Additionally, we address the
parameterized complexity of each problem, providing FPT algorithms and hardness
results
The Significance of the Many Property Problem
One of the most influential traditional objections to Adverbialism about perceptual experience is that posed by Frank Jackson’s ‘many property problem’. Perhaps largely because of this objection, few philosophers now defend Adverbialism. We argue, however, that the essence of the many property problem arises for all of the leading metaphysical theories of experience: all leading theories must simply take for granted certain facts about experience, and no theory looks well positioned to explain the facts in a straightforward way. Because of this, the many property problem isn’t on its own a good reason for rejecting Adverbialism; and nor is it a puzzle that will decide amongst the other leading theories
The significance of the many property problem
One of the most influential traditional objections to Adverbialism about perceptual experience is that posed by Frank Jackson’s ‘many property problem’. Perhaps largely because of this objection, few philosophers now defend Adverbialism. We argue, however, that the essence of the many property problem arises for all of the leading metaphysical theories of experience: all leading theories must simply take for granted certain facts about experience, and no theory looks well positioned to explain the facts in a straightforward way. Because of this, the many property problem isn’t on its own a good reason for rejecting Adverbialism; and nor is it a puzzle that will decide amongst the other leading theories
Multiplex antibiotic susceptibility testing of urinary tract infections using an electrochemical lab-on-a-chip
Urinary tract infections (UTIs) represent the most prevalent type of outpatient infection, with significant adverse health and economic burdens. Current culture-based antibiotic susceptibility testing can take up to 72Â h resulting in ineffective prescription of broad-spectrum antibiotics, poor clinical outcomes and development of further antibiotic resistance. We report an electrochemical lab-on-a-chip (LOC) for testing samples against seven clinically-relevant antibiotics. The LOC contained eight chambers, each housing an antibiotic-loaded hydrogel (cephalexin, ceftriaxone, colistin, gentamicin, piperacillin, trimethoprim, vancomycin) or antibiotic-free control, alongside a resazurin bulk-modified screen-printed electrode for electrochemical detection of metabolically active bacteria using differential pulse voltammetry. Antibiotic susceptibility in simulated UTI samples or donated human urine with either Escherichia coli or Klebsiella pneumoniae could be established within 85Â min. Incorporating electrochemical detection onto a LOC provides an inexpensive, simple method for the sensitive determination of antibiotic susceptibility that is significantly faster than using a culture-based approach
A GIS-Based Prioritisation of Coastal Legacy Mine Spoil Deposits in England and Wales for Effective Future Management
Increases in coastal flooding and erosion due to climate change threaten many coastal mine waste deposits in the UK. As such, a robust approach to prioritising sites for management is required. A spatial dataset of 9094 mine spoil deposits in England and Wales was analysed against coastal erosion and flood projections to identify deposits most at-risk. Of these, 58 were at risk of tidal flooding and 33 of coastal erosion over the coming century. Within the 10 highest-priority deposits, 426,283 m3 of spoil was at risk of release by erosion, with Blackhall Colliery (County Durham) being the largest predicted contributor
Effect of Haemophilus influenzae type b vaccination without a booster dose on invasive H influenzae type b disease, nasopharyngeal carriage, and population immunity in Kilifi, Kenya: a 15-year regional surveillance study
Background Haemophilus infl uenzae type b (Hib) conjugate vaccine, delivered as a three-dose series without a booster,
was introduced into the childhood vaccination programme in Kenya in 2001. The duration of protection and need for
a booster dose are unknown. We aimed to assess vaccine eff ectiveness, the impact of the vaccine on nasopharyngeal
carriage, and population immunity after introduction of conjugate Hib vaccine in infancy without a booster dose
in Kenya.
Methods This study took place in the Kilifi Health and Demographic Surveillance System (KHDSS), an area of Kenya
that has been monitored for vital events and migration every 4 months since 2000. We analysed sterile site cultures
for H infl uenzae type b from children (aged ≤12 years) admitted to the Kilifi County Hospital (KCH) from Jan 1, 2000,
through to Dec 31, 2014. We determined the prevalence of nasopharyngeal carriage by undertaking cross-sectional
surveys in random samples of KHDSS residents (of all ages) once every year from 2009 to 2012, and measured Hib
antibody concentrations in fi ve cross-sectional samples of children (aged ≤12 years) within the KHDSS (in 1998, 2000,
2004–05, 2007, and 2009). We calculated incidence rate ratios between the prevaccine era (2000–01) and the routineuse
era (2004–14) and defi ned vaccine eff ectiveness as 1 minus the incidence rate ratio, expressed as a percentage.
Findings 40 482 children younger than 13 years resident in KHDSS were admitted to KCH between 2000 and 2014,
38 206 (94%) of whom had their blood cultured. The incidence of invasive H infl uenzae type b disease in children
younger than 5 years declined from 62·6 (95% CI 46·0–83·3) per 100 000 in 2000–01 to 4·5 (2·5–7·5) per 100 000 in
2004–14, giving a vaccine eff ectiveness of 93% (95% CI 87–96). In the fi nal 5 years of observation (2010–14), only one
case of invasive H infl uenzae type b disease was detected in a child younger than 5 years. Nasopharyngeal H infl uenzae
type b carriage was detected in one (0·2%) of 623 children younger than 5 years between 2009 and 2012. In the 2009
serosurvey, 92 (79%; 95% CI 70–86) of 117 children aged 4–35 months had long-term protective antibody
concentrations.
Interpretation In this region of Kenya, use of a three-dose primary series of Hib vaccine without a booster dose has
resulted in a signifi cant and sustained reduction in invasive H infl uenzae type b disease. The prevalence of
nasopharyngeal carriage is low and the profi le of Hib antibodies suggests that protection wanes only after the age at
greatest risk of disease. Although continued surveillance is important to determine whether eff ective control persists,
these fi ndings suggest that a booster dose is not currently required in Kenya
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