96 research outputs found
The impact of the Iraq war on childrenÂŽs health outcomes
War and violent shocks can have long-term effects on health and human capital. Children in younger years are particularly vulnerable. This paper quantifies the effect of war on children anthropometrics using linked household and health survey data, complemented with administrative records from Iraq. The identification strategy exploits differences in war-intensity across households and areas. Estimates indicate that height-for-age Z-scores are lower for children exposed to higher war-intensity. War also leads to stunting and severe stunting among children in Iraq with potentially long-run consequences. These results are found both when using self-reported survey data on injury or mortality in the childrenâs households and administrative data on injury and mortality by governorate. Furthermore, impacts are larger on children exposed to the war in utero than those exposed later in life. Inadequate food supply does not appear to drive these results. Instead, disruptions in access to health care services and income effects from wage and/or job loss among adults are important channels through which the Iraq War lead to detrimental long-term effects on children's health. The findings are robust to including region-specific and socioeconomic controls, as well as excluding displaced households.Guerra e outros confrontos violentos podem ter efeitos de longo prazo na saĂșde e no capital humano de um paĂs ou regiĂŁo. As crianças sĂŁo o grupo etĂĄrio mais vulnerĂĄvel. Este estudo quantifica os efeitos da guerra nas medidas antropomĂ©tricas das crianças, usando dados de inquĂ©ritos sobre a saĂșde e agregado familiar e dados administrativos do Iraque. O mĂ©todo de identificação explora as diferenças em exposição Ă guerra e violĂȘncia entre regiĂ”es e agregados familiares. As estimativas apontam para menores Z-scores para o indicador altura-idade para crianças mais expostas Ă violĂȘncia. A guerra afeta tambĂ©m o crescimento das crianças, por vezes de forma severa. Os mesmos resultados sĂŁo obtidos quando sĂŁo usados dados de incidĂȘncia direta de violĂȘncia na famĂlia (calculados atravĂ©s do inquĂ©rito Ă s famĂlias) ou dados administrativos de incidĂȘncia no municĂpio. AlĂ©m disso, o impacto Ă© relativamente mais forte nas crianças que sĂŁo expostas Ă guerra ainda numa fase in utero. A alimentação inadequada nĂŁo parece ser a causa principal dos efeitos encontrados. Em vez disso, dificuldades no acesso a cuidados mĂ©dicos e redução no rendimento dos adultos causado pela perda de emprego parecem ser os fatores determinantes na maneira como a guerra no Iraque influencia a saĂșde, e em particular as medidas antropomĂ©tricas, das crianças. A robustez destes resultados Ă© comprovada pela inclusĂŁo de controlos socioeconĂłmicos e por regiĂŁo e/ou pela exclusĂŁo de agregados familiares deslocados em consequĂȘncia da guerra
Haplotype frequency estimation error analysis in the presence of missing genotype data
BACKGROUND: Increasingly researchers are turning to the use of haplotype analysis as a tool in population studies, the investigation of linkage disequilibrium, and candidate gene analysis. When the phase of the data is unknown, computational methods, in particular those employing the Expectation-Maximisation (EM) algorithm, are frequently used for estimating the phase and frequency of the underlying haplotypes. These methods have proved very successful, predicting the phase-known frequencies from data for which the phase is unknown with a high degree of accuracy. Recently there has been much speculation as to the effect of unknown, or missing allelic data â a common phenomenon even with modern automated DNA analysis techniques â on the performance of EM-based methods. To this end an EM-based program, modified to accommodate missing data, has been developed, incorporating non-parametric bootstrapping for the calculation of accurate confidence intervals. RESULTS: Here we present the results of the analyses of various data sets in which randomly selected known alleles have been relabelled as missing. Remarkably, we find that the absence of up to 30% of the data in both biallelic and multiallelic data sets with moderate to strong levels of linkage disequilibrium can be tolerated. Additionally, the frequencies of haplotypes which predominate in the complete data analysis remain essentially the same after the addition of the random noise caused by missing data. CONCLUSIONS: These findings have important implications for the area of data gathering. It may be concluded that small levels of drop out in the data do not affect the overall accuracy of haplotype analysis perceptibly, and that, given recent findings on the effect of inaccurate data, ambiguous data points are best treated as unknown
Sequence embedding for fast construction of guide trees for multiple sequence alignment
<p>Abstract</p> <p>Background</p> <p>The most widely used multiple sequence alignment methods require sequences to be clustered as an initial step. Most sequence clustering methods require a full distance matrix to be computed between all pairs of sequences. This requires memory and time proportional to <it>N</it><sup>2 </sup>for <it>N </it>sequences. When <it>N </it>grows larger than 10,000 or so, this becomes increasingly prohibitive and can form a significant barrier to carrying out very large multiple alignments.</p> <p>Results</p> <p>In this paper, we have tested variations on a class of embedding methods that have been designed for clustering large numbers of complex objects where the individual distance calculations are expensive. These methods involve embedding the sequences in a space where the similarities within a set of sequences can be closely approximated without having to compute all pair-wise distances.</p> <p>Conclusions</p> <p>We show how this approach greatly reduces computation time and memory requirements for clustering large numbers of sequences and demonstrate the quality of the clusterings by benchmarking them as guide trees for multiple alignment. Source code is available for download from <url>http://www.clustal.org/mbed.tgz</url>.</p
A measurement of the millimetre emission and the Sunyaev-Zel'dovich effect associated with low-frequency radio sources
We present a statistical analysis of the millimetre-wavelength properties of 1.4GHz-selected sources and a detection of the SunyaevâZelâdovich (SZ) effect associated with the haloes that host them. We stack data at 148, 218 and 277GHz from the Atacama Cosmology Telescope at the positions of a large sample of radio AGN selected at 1.4GHz. The thermal SZ effect associated with the haloes that host the AGN is detected at the 5Ï level through its spectral signature, representing a statistical detection of the SZ effect in some of the lowest mass haloes (average M 200 â 10 13 M. h â1 70 ) studied to date. The relation between the SZ effect and mass (based on weak lensing measurements of radio galaxies) is consistent with that measured by Planck for local bright galaxies. In the context of galaxy evolution models, this study confirms that galaxies with radio AGN also typically support hot gaseous haloes. Adding Herschel observations allows us to show that the SZ signal is not significantly contaminated by dust emission. Finally, we analyse the contribution of radio sources to the angular power spectrum of the cosmic microwave background
A Complete Analysis of HA and NA Genes of Influenza A Viruses
BACKGROUND: More and more nucleotide sequences of type A influenza virus are available in public databases. Although these sequences have been the focus of many molecular epidemiological and phylogenetic analyses, most studies only deal with a few representative sequences. In this paper, we present a complete analysis of all Haemagglutinin (HA) and Neuraminidase (NA) gene sequences available to allow large scale analyses of the evolution and epidemiology of type A influenza. METHODOLOGY/PRINCIPAL FINDINGS: This paper describes an analysis and complete classification of all HA and NA gene sequences available in public databases using multivariate and phylogenetic methods. CONCLUSIONS/SIGNIFICANCE: We analyzed 18,975 HA sequences and divided them into 280 subgroups according to multivariate and phylogenetic analyses. Similarly, we divided 11,362 NA sequences into 202 subgroups. Compared to previous analyses, this work is more detailed and comprehensive, especially for the bigger datasets. Therefore, it can be used to show the full and complex phylogenetic diversity and provides a framework for studying the molecular evolution and epidemiology of type A influenza virus. For more than 85% of type A influenza HA and NA sequences into GenBank, they are categorized in one unambiguous and unique group. Therefore, our results are a kind of genetic and phylogenetic annotation for influenza HA and NA sequences. In addition, sequences of swine influenza viruses come from 56 HA and 45 NA subgroups. Most of these subgroups also include viruses from other hosts indicating cross species transmission of the viruses between pigs and other hosts. Furthermore, the phylogenetic diversity of swine influenza viruses from Eurasia is greater than that of North American strains and both of them are becoming more diverse. Apart from viruses from human, pigs, birds and horses, viruses from other species show very low phylogenetic diversity. This might indicate that viruses have not become established in these species. Based on current evidence, there is no simple pattern of inter-hemisphere transmission of avian influenza viruses and it appears to happen sporadically. However, for H6 subtype avian influenza viruses, such transmissions might have happened very frequently and multiple and bidirectional transmission events might exist
Magnetic Field Properties inside the Jet of Mrk 421: Multiwavelength Polarimetry Including the Imaging X-ray Polarimetry Explorer
We conducted a polarimetry campaign from radio to X-ray wavelengths of the
high-synchrotron-peak (HSP) blazar Mrk 421, including Imaging X-ray Polarimetry
Explorer (IXPE) measurements on 2022 December 6-8. We detected X-ray
polarization of Mrk 421 with a degree of =141 and an
electric-vector position angle =1073 in the 2-8
keV band. From the time variability analysis, we find a significant episodic
variation in . During 7 months from the first IXPE pointing of
Mrk 421 in 2022 May, varied across the range of 0 to
180, while maintained similar values within
10-15. Furthermore, a swing in in 2022 June was
accompanied by simultaneous spectral variations. The results of the
multiwavelength polarimetry show that the X-ray polarization degree was
generally 2-3 times greater than that at longer wavelengths, while the
polarization angle fluctuated. Additionally, based on radio, infrared, and
optical polarimetry, we find that rotation of occurred in the opposite
direction with respect to the rotation of over longer timescales
at similar epochs. The polarization behavior observed across multiple
wavelengths is consistent with previous IXPE findings for HSP blazars. This
result favors the energy-stratified shock model developed to explain variable
emission in relativistic jets. The accompanying spectral variation during the
rotation can be explained by a fluctuation in the physical
conditions, e.g., in the energy distribution of relativistic electrons. The
opposite rotation direction of between the X-ray and longer-wavelength
polarization accentuates the conclusion that the X-ray emitting region is
spatially separated from that at longer wavelengths.Comment: 17 pages, 13 figures, 4 tables; Accepted for publication in A&
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Abstract
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and lowâmiddle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of âsingle-useâ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for lowâmiddle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both highâ and lowâmiddleâincome countries
Instability in progressive multiple sequence alignment algorithms
Background: Progressive alignment is the standard approach used to align large numbers of sequences. As with all heuristics, this involves a trade off between alignment accuracy and computation time. Results: We examine this trade off and find that, because of a loss of information in the early steps of the approach, the alignments generated by the most common multiple sequence alignment programs are inherently unstable, and simply reversing the order of the sequences in the input file will cause a different alignment to be generated. Although this effect is more obvious with larger numbers of sequences, it can also be seen with data sets in the order of one hundred sequences. We also outline the means to determine the number of sequences in a data set beyond which the probability of instability will become more pronounced. Conclusions: This has major ramifications for both the designers of large-scale multiple sequence alignment algorithms, and for the users of these alignments.Science Foundation Irelan
OD-seq: outlier detection in multiple sequence alignments
Background: Multiple sequence alignments (MSA) are widely used in sequence analysis for a variety of tasks. Outlier sequences can make downstream analyses unreliable or make the alignments less accurate while they are being constructed. This paper describes a simple method for automatically detecting outliers and accompanying software called OD-seq. It is based on finding sequences whose average distance to the rest of the sequences in a dataset, is anomalous. Results: The software can take a MSA, distance matrix or set of unaligned sequences as input. Outlier sequences are found by examining the average distance of each sequence to the rest. Anomalous average distances are then found using the interquartile range of the distribution of average distances or by bootstrapping them. The complexity of any analysis of a distance matrix is normally at least O(N2 ) for N sequences. This is prohibitive for large N but is reduced here by using the mBed algorithm from Clustal Omega. This reduces the complexity to O(N log(N)) which makes even very large alignments easy to analyse on a single core. We tested the ability of OD-seq to detect outliers using artificial test cases of sequences from Pfam families, seeded with sequences from other Pfam families. Using a MSA as input, OD-seq is able to detect outliers with very high sensitivity and specificity. Conclusion: OD-seq is a practical and simple method to detect outliers in MSAs. It can also detect outliers in sets of unaligned sequences, but with reduced accuracy. For medium sized alignments, of a few thousand sequences, it can detect outliers in a few seconds.Science Foundation Irelan
Systematic exploration of guide-tree topology effects for small protein alignments
Background: Guide-trees are used as part of an essential heuristic to enable the calculation of multiple sequence alignments. They have been the focus of much method development but there has been little effort at determining systematically, which guide-trees, if any, give the best alignments. Some guide-tree construction schemes are based on pair-wise distances amongst unaligned sequences. Others try to emulate an underlying evolutionary tree and involve various iteration methods. Results: We explore all possible guide-trees for a set of protein alignments of up to eight sequences. We find that pairwise distance based default guide-trees sometimes outperform evolutionary guide-trees, as measured by structure derived reference alignments. However, default guide-trees fall way short of the optimum attainable scores. On average chained guide-trees perform better than balanced ones but are not better than default guide-trees for small alignments. Conclusions: Alignment methods that use Consistency or hidden Markov models to make alignments are less susceptible to sub-optimal guide-trees than simpler methods, that basically use conventional sequence alignment between profiles. The latter appear to be affected positively by evolutionary based guide-trees for difficult alignments and negatively for easy alignments. One phylogeny aware alignment program can strongly discriminate between good and bad guide-trees. The results for randomly chained guide-trees improve with the number of sequences.Science Foundation Irelan
- âŠ