Micro-geographic risk factors for malarial infection.

BACKGROUND: Knowledge of geography is integral to the study of insect-borne infectious disease such as malaria. This study was designed to evaluate whether geographic parameters are associated with malarial infection in the East Sepik province of Papua New Guinea (PNG), a remote area where malaria is a major cause of morbidity and mortality. METHODS: A global positioning system (GPS) unit was used at each village to collect elevation, latitude and longitude data. Concurrently, a sketch map of each village was generated and the villages were sub-divided into regions of roughly equal populations. Blood samples were taken from subjects in each region using filter paper collection. The samples were later processed using nested PCR for qualitative determination of malarial infection. The area was mapped using the GPS-information and overlaid with prevalence data. Data tables were examined using traditional chi square statistical techniques. A logistic regression analysis was then used to determine the significance of geographic risk factors including, elevation, distance from administrative centre and village of residence. RESULTS: Three hundred and thirty-two samples were included (24% of the total estimated population). Ninety-six were positive, yielding a prevalence of 29%. Chi square testing within each village found a non-random distribution of cases across sub-regions (p < 0.05). Multivariate logistic regression techniques suggested malarial infection changed with elevation (OR = 0.64 per 10 m, p < 0.05) and distance from administrative centre (OR = 1.3 per 100 m, p < 0.05). CONCLUSION: These results suggest that malarial infection is significantly and independently associated with lower elevation and greater distance from administrative centre in a rural area in PNG. This type of analysis can provide information that may be used to target specific areas in developing countries for malaria prevention and treatment

A Quantile Variant of the EM Algorithm and Its Applications to Parameter Estimation with Interval Data

The expectation-maximization (EM) algorithm is a powerful computational technique for finding the maximum likelihood estimates for parametric models when the data are not fully observed. The EM is best suited for situations where the expectation in each E-step and the maximization in each M-step are straightforward. A difficulty with the implementation of the EM algorithm is that each E-step requires the integration of the log-likelihood function in closed form. The explicit integration can be avoided by using what is known as the Monte Carlo EM (MCEM) algorithm. The MCEM uses a random sample to estimate the integral at each E-step. However, the problem with the MCEM is that it often converges to the integral quite slowly and the convergence behavior can also be unstable, which causes a computational burden. In this paper, we propose what we refer to as the quantile variant of the EM (QEM) algorithm. We prove that the proposed QEM method has an accuracy of $O(1/K^2)$ while the MCEM method has an accuracy of $O_p(1/\sqrt{K})$. Thus, the proposed QEM method possesses faster and more stable convergence properties when compared with the MCEM algorithm. The improved performance is illustrated through the numerical studies. Several practical examples illustrating its use in interval-censored data problems are also provided

Fourier transform spectroscopy and cross section measurements of the Herzberg III bands of O2 at 295 K

The absorption bands of the Herzberg III of O2 at 295 K were measured using Fourier transform spectrometer. The rotational line positions were determined, as well as the rotational line strengths and the branching ratios. The band oscillator strengths from the sum of the strengths of the individual rotational lines were shown.published_or_final_versio

Landscape scale conservation: incentives for cross-property action

Production landscapes are critical for biodiversity conservation. Individual landholders can contribute but the real challenge is coordinated cross-property action at a landscape scale. This paper describes 2 projects through which we have attempted to better understand that challenge. The ‘Communities in Landscapes’ project (Caring for Our Country 2009-2012) provided coordinated advice and training to develop cross-property biodiversity plans and $70k for each of 7 landholder groups for the initial phase of the implementation. The project generated collaboration on landscape scale biodiversity conservation, but without ongoing support the benefits achieved could be soon lost. The ‘Increasing landholder collaboration for landscape scale conservation’ project (NSW Environmental Trust 2016-2017) is exploring the nature and extent of collaboration, and the opportunities provided by collaboration for public and private benefit. The vision is for landholders to develop ‘Landscape Corporations’ which are the vehicle for integrating production and conservation for landholders sharing the same landscape

The application of a VUV Fourier transform spectrometer and synchrotron radiation source to measurements of: II. The δ(1,0) band of NO

Line-by-line photoabsorption cross-sections of the NO δ(1,0) band were measured with the VUV Fourier transform spectrometer from Imperial College, London, using synchrotron radiation at Photon Factory, KEK, Japan, as a continuum light source. The analysis of the NO δ(1,0) band provides accurate rotational line positions and term values as well as the photoabsorption cross-sections. The molecular constants of the C(1)2 II level are found to be T0 = 54 690.155±0.03 cm–1, Bv = 1.944 06±0.000 62 cm–1, Dv = (5.91±0.42)×10–5 cm–1, AD = –0.0187±0.0050 cm–1, p = –0.0189±0.0037 cm–1, and q = –0.015 21±0.000 20 cm–1. The sum of the line strengths for all rotational transitions of the NO δ(1,0) band is determined as 4.80×10–15 cm2 cm–1, corresponding to a band oscillator strength of 0.0054±0.0003.published_or_final_versio

F-Theory GUT Vacua on Compact Calabi-Yau Fourfolds

We present compact three-generation F-theory GUT models meeting in particular the constraints of D3-tadpole cancellation and D-term supersymmetry. To this end we explicitly construct elliptically fibered Calabi-Yau fourfolds as complete intersections in a toric ambient space. Toric methods enable us to control the singular geometry of the SU(5) GUT model. The GUT brane wraps a non-generic del Pezzo surface admitting GUT symmetry breaking via hypercharge flux. It is contractible to a curve and we demonstrate the existence of a consistent decoupling limit. We compute the Euler characteristic of the singular Calabi-Yau fourfold to show that our three-generation flux solutions obtained via the spectral cover construction are consistent with D3-tadpole cancellation.Comment: 22+12 pages; v2: minor clarifications on decoupling limi

The application of a VUV Fourier transform spectrometer and synchrotron radiation source to measurements of: I. the β(9,0) band of NO

State-of-the-art models of the vacuum ultraviolet (VUV) absorbing properties of the atmosphere call for absorption cross sections with detail on the scale of the Doppler widths. As a consequence, spectroscopic data at resolving powers of the order of 10 6 are needed. To meet these requirements in the vacuum ultraviolet region, we have used the VUV Fourier transform spectrometer from Imperial College, London, at the synchrotron radiation facility at Photon Factory, KEK, Japan, to measure photoabsorption cross sections of NO from 195 to 160 nm, and of O 2 from 185 to 175 nm. The analysis of the β(9,0) band (B 2Π r-X 2Π r) of NO provides accurate rotational line positions and term values. Molecular constants of the B(9) 2Π level are T 0=54205.097±0.012cm -1, A=45.320±0.021cm -1, B υ=1.01672±0.00016cm -1, D υ=(10.61±0.32)×10 -6cm -1, and A D=0.00122±0.00011cm -1. The rotational line strengths and the branching ratios are also presented. The band oscillator strength is obtained as f=2.65×10 -4. © 1998 American Institute of Physics.published_or_final_versio

Sensory neuron–derived NaV1.7 contributes to dorsal horn neuron excitability

Expression of the voltage-gated sodium channel NaV1.7 in sensory neurons is required for pain sensation. We examined the role of NaV1.7 in the dorsal horn of the spinal cord using an epitope-tagged NaV1.7 knock-in mouse. Immuno–electron microscopy showed the presence of NaV1.7 in dendrites of superficial dorsal horn neurons, despite the absence of mRNA. Rhizotomy of L5 afferent nerves lowered the levels of NaV1.7 in the dorsal horn. Peripheral nervous system–specific NaV1.7 null mutant mice showed central deficits, with lamina II dorsal horn tonic firing neurons more than halved and single spiking neurons more than doubled. NaV1.7 blocker PF05089771 diminished excitability in dorsal horn neurons but had no effect on NaV1.7 null mutant mice. These data demonstrate an unsuspected functional role of primary afferent neuron-generated NaV1.7 in dorsal horn neurons and an expression pattern that would not be predicted by transcriptomic analysis

Multiple reassortment events in the evolutionary history of H1N1 influenza A virus since 1918

The H1N1 subtype of influenza A virus has caused substantial morbidity and mortality in humans, first documented in the global pandemic of 1918 and continuing to the present day. Despite this disease burden, the evolutionary history of the A/H1N1 virus is not well understood, particularly whether there is a virological basis for several notable epidemics of unusual severity in the 1940s and 1950s. Using a data set of 71 representative complete genome sequences sampled between 1918 and 2006, we show that segmental reassortment has played an important role in the genomic evolution of A/H1N1 since 1918. Specifically, we demonstrate that an A/H1N1 isolate from the 1947 epidemic acquired novel PB2 and HA genes through intra-subtype reassortment, which may explain the abrupt antigenic evolution of this virus. Similarly, the 1951 influenza epidemic may also have been associated with reassortant A/H1N1 viruses. Intra-subtype reassortment therefore appears to be a more important process in the evolution and epidemiology of H1N1 influenza A virus than previously realized

Lack of Evidence for an Association between Iridovirus and Colony Collapse Disorder

Colony collapse disorder (CCD) is characterized by the unexplained losses of large numbers of adult worker bees (Apis mellifera) from apparently healthy colonies. Although infections, toxins, and other stressors have been associated with the onset of CCD, the pathogenesis of this disorder remains obscure. Recently, a proteomics study implicated a double-stranded DNA virus, invertebrate iridescent virus (Family Iridoviridae) along with a microsporidium (Nosema sp.) as the cause of CCD. We tested the validity of this relationship using two independent methods: (i) we surveyed healthy and CCD colonies from the United States and Israel for the presence of members of the Iridovirus genus and (ii) we reanalyzed metagenomics data previously generated from RNA pools of CCD colonies for the presence of Iridovirus-like sequences. Neither analysis revealed any evidence to suggest the presence of an Iridovirus in healthy or CCD colonies