When worlds collide: where and when anophelines and humans interact

Malaria is a disease spread by mosquitoes and kills almost half a million people each year. While substantial gains have been made in combatting the disease, progress has stalled partly because of changes in mosquito behaviour, resistance to the insecticides in vector-control measures, drug resistance in the parasites, inadequate financing, a lack of political support as well as a host of other factors. These vector control measures have been successful since the 1990s in reducing malaria-related mortality; however, their efficacy is now waning. New tools are needed to complement the current vector control measures and combat outdoor biting; however, to develop and roll out new tools the behaviour of mosquitoes and humans needs to be better understood. Malaria is an endemic problem in the Solomon Islands and is primarily transmitted by Anopheles farauti. This study examined the behaviour of An. farauti mosquitoes and humans in the Solomon Island and Austrialia in four distinct components. The first component optimized the barrier screen method for mosquito collections. The second component used these optimized barrier screens to collect and record mosquito distributions in Solomon Island villages. The third component used movement diaries to record human behaviour in Solomon Island villagers. The fourth component explored serological techniques to measure mosquito-human interactions. The characteristics of barrier screens (colour, weight and design) and frequency of inspection were found to be important determinants affecting the collection efficiency. The results for optimising barrier screens indicated that black coloured, medium weighted shade cloth maximized An. farauti collection numbers including the first ever-recorded distributions of sugar-fed and male An. farauti. Anopheles farauti activity including biting in Solomon Islands villages peaked during 7-8pm. During this period of peak biting the majority of people were outdoors in the peri-domestic area, predominantly on the veranda or in adjacent kitchen buildings. Therefore, greatest interactions between the human and the malaria vector populations and therefore the most likely area of malaria transmission is in the early evening in this peri-domestic space. To better evaluate the risk associated with humans being bitten by An. farauti the serological response of humans to a mosquito salivary gland antigen was investigated in the Solomon Islands. While of insufficient sensitivity to guide programs when using the gSG6 antigen, this approach holds great promise and might be improved by using antigens from An. farauti in the assay. The peri-domestic space is identified as the area of greatest risk but also of greatest potential for vector control. The implications of this study indicate that the current vector control measure (insecticide treated nets) are not being used during the peak biting period. Focusing mosquito control on the peridomestic spaces in villages is needs as this is where the highest transmission potential exists. New tools targeting this area are needed to minimize interactions between the mosquito and human populations

Solid Propellant Power Systems for Normal and Emergency Space Operations

The ability of man to function safely both inside and out of his spacecraft will become even more critical after his pioneering flights such as Gemini and Apollo are completed. As greater numbers of astronauts make flights of long duration, survival may well be a function of a number of extravehicular activities such as routine vehicle inspection, emergency maintenance and repair. erection of structures and platforms, and rescue operations. Current systems remain bulky, heavy, and a possible source of hazard and malfunction. The solid-propellant space power systems examined here are small, light, manually or automatically operated, and have the capability not only to propel and stabilize man in space, but provide a means of power to do an extremely wide variety of critical functions outside or within a spacecraft. It has often been stated that there is no need to replace a working system. The authors of this paper are in full agreement with this statement. Let us assume for purposes of illustration a simplified spacecraft which requires only two systems for its operation, one in the nose which is hydraulic, and another in the tail which is electrical. Both are well designed and completely workable. As long as they are capable of performing their required function and as long as they are capable of growth to meet additional mission requirements, there should be no valid reason to replace either by a solid-propellant hot gas system. But let us consider further. In the event of a failure of either system during a flight, the parts of one system cannot be used in a repair of the other. It would be very surpris - ing if the motors, switches, etc. of the electrical system could be substituted in any way for any of the valves and cylinders of the various hydraulic devices and vice versa. If, however, both systems were replaced with a compatible gas generator powered system, a failure in either end of the spacecraft could use parts and prime movers frorn the other. The present philosophy for space-borne systems and components imposes as criteria of design extremely high standards of operational reliability and there is no quarrel with this doctrine. However, high reliability from the standpoint of completion of a manned space mission ·does not necessarily imply complete maintenance- free reliability during the entire operating life of the various systems involved. We are dealing here with a vehicle containing a crew of thinking, random decision making, non-linear operating, human beings rather than an inanimate object which is capable of performing only the actions for which it has been pre-programmed. At the present time, crew members of space vehicles perform a variety of maintenance functions which enhance the operability of themselves and their vehicles. Such simple non-programmed act ions as tuning a radio or adjusting a thermostat can be considered as part of the maintenance functions. Bad communications? A pilot will naturally and instinctively tune his command receiver for increased performance or change to another communications channel where reception might be better. Too hot? A crew member turns down the thermostat on his suit a couple of notches to compensate for the extra heat load caused by unplanned exertion

Confluence and contours: reflexive management of environmental risk

Government institutions have responsibilities to distribute risk management funds meaningfully and to be accountable for their choices. We took a macro-level sociological approach to understanding the role of government in managing environmental risks, and insights from micro-level psychology to examine individual-level risk-related perceptions and beliefs. Survey data from 2,068 U.K. citizens showed that lay people's funding preferences were associated positively with beliefs about responsibility and trust, yet associations with perception varied depending on risk type. Moreover, there were risk-specific differences in the funding preferences of the lay sample and 29 policymakers. A laboratory-based study of 109 participants examined funding allocation in more detail through iterative presentation of expert information. Quantitative and qualitative data revealed a meso-level framework comprising three types of decisionmakers who varied in their willingness to change funding allocation preferences following expert information: adaptors, responders, and resistors. This research highlights the relevance of integrated theoretical approaches to understanding the policy process, and the benefits of reflexive dialogue to managing environmental risks.Department of Environment Food and Rural Affairs, EPSRC, NERC, ESR

Unique fine scale village spatial-temporal distributions of Anopheles farauti differ by physiological state and sex

Background: The ecology of many mosquitoes, including Anopheles farauti, the dominant malaria vector in the southwest Pacific including the Solomon Islands, remains inadequately understood. Studies to map fine scale vector distributions are biased when trapping techniques use lures that will influence the natural movements of mosquitoes by attracting them to traps. However, passive collection methods allow the detailed natural distributions of vector populations by sex and physiological states to be revealed. Methods: The barrier screen, a passive mosquito collection method along with human landing catches were used to record An. farauti distributions over time and space in two Solomon Island villages from May 2016 to July 2017. Results: Temporal and spatial distributions of over 15,000 mosquitoes, including males as well as unfed, host seeking, blood-fed, non-blood fed and gravid females were mapped. These spatial and temporal patterns varied by species, sex and physiological state. Sugar-fed An. farauti were mostly collected between 10–20 m away from houses with peak activity from 18:00 to 19:00 h. Male An. farauti were mostly collected greater than 20 m from houses with peak activity from 19:00 to 20:00 h. Conclusions: Anopheles farauti subpopulations, as defined by physiological state and sex, are heterogeneously distributed in Solomon Island villages. Understanding the basis for these observed heterogeneities will lead to more accurate surveillance of mosquitoes and will enable spatial targeting of interventions for greater efficiency and effectiveness of vector control

Protecting the peri-domestic environment: the challenge for eliminating residual malaria

Malaria transmission after universal access and use of malaria preventive services is known as residual malaria transmission. The concurrent spatial-temporal distributions of people and biting mosquitoes in malaria endemic villages determines where and when residual malaria transmission occurs. Understanding human and vector population behaviors and movements is a critical first step to prevent mosquito bites to eliminate residual malaria transmission. This study identified where people in the Solomon Islands are over 24-hour periods. Participants (59%) were predominantly around the house but not in their house when most biting by Anopheles farauti, the dominant malaria vector, occurs. While 84% of people slept under a long-lasting insecticide-treated bed net (LLIN), on average only 7% were under an LLIN during the 18:00 to 21:00 h peak mosquito biting period. On average, 34% of participants spend at least one night away from their homes each fortnight. Despite high LLIN use while sleeping, most human biting by An. farauti occurs early in the evening before people go to sleep when people are in peri-domestic areas (predominantly on verandas or in kitchen areas). Novel vector control tools that protect individuals from mosquito bites between sundown and when people sleep are needed for peri-domestic areas

Extended General Relativity: large-scale antigravity and short-scale gravity with \omega=-1 from five dimensional vacuum

Considering a five-dimensional (5D) Riemannian spacetime with a particular stationary Ricci-flat metric, we obtain in the framework of the induced matter theory an effective 4D static and spherically symmetric metric which give us ordinary gravitatory solutions on small (planetary and astrophysical) scales, but repulsive (antigravity) forces on very large (cosmological) scales with \omega = -1. Our approach is an unified manner to describe dark energy, dark matter and ordinary matter. We illustrate the theory with two examples, the solar system and the great attractor. From the geometrical point of view, these results follow from the assumption that exists a confining force that make possible that test particles move on a given 4D hypersurface.Comment: Final version. To be published in Phys. Lett.

Human exposure to Anopheles farauti bites in the Solomon Islands is not associated with IgG antibody response to the gSG6 salivary protein of Anopheles gambiae.

BACKGROUND: Mosquito saliva elicits immune responses in humans following mosquito blood feeding. Detection of human antibodies recognizing the Anopheles gambiae salivary gland protein 6 (gSG6) or the gSG6-P1 peptide in residents of Africa, South America and Southeast Asia suggested the potential for these antibodies to serve as a universal marker to estimate human biting rates. Validating the utility of this approach requires concurrent comparisons of anopheline biting rates with antibodies to the gSG6 protein to determine the sensitivity and specificity of the assay for monitoring changes in vector populations. This study investigated whether seroprevalence of anti-gSG6 antibodies in humans reflected the relative exposure to Anopheles farauti bites in the Solomon Islands as estimated from sympatric human landing catches. METHODS: Human biting rates by An. farauti were estimated by landing catches at 10 sampling sites in each of 4 villages during the wet and dry seasons. Human serum samples from these same villages were also collected during the wet and dry seasons and analysed for antibody recognition of the gSG6 antigen by the Luminex xMAP© platform. Antibody titres and prevalence were compared to HLCs at the sampling sites nearest to participants' residences for utility of anti-gSG6 antibodies to estimate human exposure to anopheline bites. RESULTS: In this study in the Solomon Islands only 11% of people had very high anti-gSG6 antibody titres, while other individuals did not recognize gSG6 despite nightly exposures of up to 190 bites by An. farauti. Despite clear spatial differences in the human biting rates within and among villages, associations between anti-gSG6 antibody titres and biting rates were not found. CONCLUSIONS: Few studies to date have concurrently measured anopheline biting rates and the prevalence of human antibodies to gSG6. The lack of association between anti-gSG6 antibody titres and concurrently measured human biting rates suggests that the assay for human anti-gSG6 antibodies lacks sufficient sensitivity to be a biomarker of An. farauti exposure at an epidemiologically relevant scale. These findings imply that an improvement in the sensitivity of serology to monitor changes in anopheline biting exposure may require the use of saliva antigens from local anophelines, and this may be especially true for species more distantly related to the African malaria vector An. gambiae

Accurate reconstruction of insertion-deletion histories by statistical phylogenetics

The Multiple Sequence Alignment (MSA) is a computational abstraction that represents a partial summary either of indel history, or of structural similarity. Taking the former view (indel history), it is possible to use formal automata theory to generalize the phylogenetic likelihood framework for finite substitution models (Dayhoff's probability matrices and Felsenstein's pruning algorithm) to arbitrary-length sequences. In this paper, we report results of a simulation-based benchmark of several methods for reconstruction of indel history. The methods tested include a relatively new algorithm for statistical marginalization of MSAs that sums over a stochastically-sampled ensemble of the most probable evolutionary histories. For mammalian evolutionary parameters on several different trees, the single most likely history sampled by our algorithm appears less biased than histories reconstructed by other MSA methods. The algorithm can also be used for alignment-free inference, where the MSA is explicitly summed out of the analysis. As an illustration of our method, we discuss reconstruction of the evolutionary histories of human protein-coding genes.Comment: 28 pages, 15 figures. arXiv admin note: text overlap with arXiv:1103.434

Ortholog identification in the presence of domain architecture rearrangement

Ortholog identification is used in gene functional annotation, species phylogeny estimation, phylogenetic profile construction and many other analyses. Bioinformatics methods for ortholog identification are commonly based on pairwise protein sequence comparisons between whole genomes. Phylogenetic methods of ortholog identification have also been developed; these methods can be applied to protein data sets sharing a common domain architecture or which share a single functional domain but differ outside this region of homology. While promiscuous domains represent a challenge to all orthology prediction methods, overall structural similarity is highly correlated with proximity in a phylogenetic tree, conferring a degree of robustness to phylogenetic methods. In this article, we review the issues involved in orthology prediction when data sets include sequences with structurally heterogeneous domain architectures, with particular attention to automated methods designed for high-throughput application, and present a case study to illustrate the challenges in this area

Strategic risk appraisal. Comparing expert- and literature-informed consequence assessments for environmental policy risks receiving national attention

Strategic risk appraisal (SRA) has been applied to compare diverse policy level risks to and from the environment in England and Wales. Its application has relied on expert-informed assessments of the potential consequences from residual risks that attract policy attention at the national scale. Here we compare consequence assessments, across environmental, economic and social impact categories that draw on ‘expert’- and ‘literature-based’ analyses of the evidence for 12 public risks appraised by Government. For environmental consequences there is reasonable agreement between the two sources of assessment, with expert-informed assessments providing a narrower dispersion of impact severity and with median values similar in scale to those produced by an analysis of the literature. The situation is more complex for economic consequences, with a greater spread in the median values, less consistency between the two assessment types and a shift toward higher severity values across the risk portfolio. For social consequences, the spread of severity values is greater still, with no consistent trend between the severities of impact expressed by the two types of assessment. For the latter, the findings suggest the need for a fuller representation of socioeconomic expertise in SRA and the workshops that inform SRA output