A systematic review of instrumental variable analyses using geographic region as an instrument.

BACKGROUND: Instrumental variables analysis is a methodology to mitigate the effects of measured and unmeasured confounding in observational studies of treatment effects. Geographic area is increasingly used as an instrument. METHODS: We conducted a literature review to determine the properties of geographic area in studies of cancer treatments. We identified cancer studies performed in the United States which incorporated instrumental variable analysis with area-wide treatment rate within a geographic region as the instrument. We assessed the degree of treatment variability between geographic regions, assessed balance of measured confounders afforded by geographic area and compared the results of instrumental variable analysis to those of multivariable methods. RESULTS: Geographic region as an instrument was relatively common, with 22 eligible studies identified, many of which were published in high-impact journals. Treatment rates did not vary greatly by geographic region. Covariates were not balanced by the instrument in the majority of studies. Eight out of eleven studies found statistically significant effects of treatment on multivariable analysis but not for instrumental variables, with the central estimates of the instrumental variables analysis generally being closer to the null. CONCLUSIONS: We recommend caution and an investigation of IV assumptions when considering the use of geographic region as an instrument in observational studies of cancer treatments. The value of geographic region as an instrument should be critically evaluated in other areas of medicine.

An eighteenth century travelling theodolite / Um teodolito viajante do século XVIII

Abstract An old topographic compass displayed in a showroom of the Museu de Astronomia e Ciências Afins (MAST), in Rio de Janeiro, Brazil, took our curiosity namely because of its resemblance to a theodolite, described by J.H. de Magellan. Not many things were known about its previous history. From the different documents studied, and the characteristics of this singular theodolite, it must have belonged to the collections of instruments acquired for the Brazilian border demarcations undertaken after the Santo Ildefonso Treaty, agreed to by the Portuguese and Spanish courts in 1777. Several instruments were bought in London, and supervised and chosen by Magellan, the Portuguese instruments expert. We present arguments in favour of this conclusion.

Resumo Um antigo compasso topográfico em exibição no Museu de Astronomia e Ciências Afins (Mast), no Rio de Janeiro, chamou-nos a atenção por sua semelhança com um teodolito descrito por João Jacinto de Magalhães. Pouco era conhecido sobre sua história prévia. De acordo com os diversos documentos estudados e as caracteríticas desse único teodolito, ele deve ter pertencido às coleções de instrumentos adquiridos para a demarcação das fronteiras brasileiras realizadas após o Tratato de Santo Ildefonso, acordado entre as cortes portuguesa e espanhola em 1777. Vários instrumentos foram comprados em Londres, supervisionados e escolhidos por Magalhães, o perito português em instrumentos. Apresentamos argumentos que corroboram essa conclusão.

An eighteenth century travelling theodolite.

An old topographic compass displayed in a showroom of the Museu de Astronomia e Ciências Afins (MAST), in Rio de Janeiro, Brazil, took our curiosity namely because of its resemblance to a theodolite, described by J.H. de Magellan. Not many things were known about its previous history. From the different documents studied, and the characteristics of this singular theodolite, it must have belonged to the collections of instruments acquired for the Brazilian border demarcations undertaken after the Santo Ildefonso Treaty, agreed to by the Portuguese and Spanish courts in 1777. Several instruments were bought in London, and supervised and chosen by Magellan, the Portuguese instruments expert. We present arguments in favour of this conclusion.

Andean region: a shapefile of Morrone's (2015) biogeographical regionalisation.

Morrone's (2015) biogeographic regionalisation of the Andean region is based on the distributional ranges of terrestrial plants and animals. It is the most comprehensive and methodologically supported biogeographical scheme for the region to date. The Andean region comprises one transition zone (the South American transition zone), three subregions (Central Chilean, Subantarctic and Patagonian) and 15 provinces (Morrone, 2015).

Evaluation of the altimetry from SRTM-3 and planimetry from high-resolution PALSAR FBD data for semi-detailed topographic mapping in the Amazon Region

The Brazilian Amazon has a deficit of 35 percent of coverage regarding topographic mapping at semi-detailed (1:100,000) scale. This paper presents an alternative to overcome this scenario using a combination of planialtimetric information from two orbital SAR (Synthetic Aperture Radar) missions. The altimetry was acquired from Shuttle Radar Topography Mission (SRTM), while the planimetry was provided from Fine Beam Dual (FBD) images of the Phased Array L-band Synthetic Aperture Radar (PALSAR) sensor. The research was carried out in the mountainous area of the Serra dos Carajás (Pará State), located on the Amazon region. The quality of the orbital topographic information was evaluated regarding precise planialtimetric measurements acquired from Global Positioning System (GPS) field campaigns. The evaluations were performed following two approaches: (1) the use of Root Mean Square Error (RMSE) and (2) tendency and precision hypothesis tests. The investigation has shown that the planialtimetric quality of the orbital products fulfilled the Brazilian Map Accuracy Standards requirements for 1:100,000 A Class map. Thus, the use of combination of information provided by PALSAR and SRTM-3 data can be considered a promising alternative for production and update of semi-detailed topographic mapping in similar environments of the Amazon region, where topographic information is lacking or presents low quality.

A Amazônia brasileira possui um déficit de 35 por cento de cobertura em relação ao mapeamento topográfico na escala de semi-detalhe (1:100.000). Este trabalho apresenta uma alternativa para superar este cenário usando a combinação de informação planialtimétrica de duas missões SAR (Radar de Abertura Sintética) orbitais. A altimetria foi adquirida da Shuttle Radar Topography Mission (SRTM), enquanto que a planimetria foi fornecida de imagens Fine Beam Dual (FBD) do sensor Phased Array L-band Synthetic Aperture Radar (PALSAR). A pesquisa foi desenvolvida na área montanhosa da Serra dos Carajás (Estado do Pará) localizada na região Amazônica. A qualidade das informações topográficas orbitais foi avaliada em relação a medidas planialtimétricas precisas adquiridas de campanhas de campo com Sistema de Posicionamento Global (GPS). As avaliações foram realizadas seguindo duas abordagens: (1) o uso de Erro Médio Quadrático (EMQ) e (2) testes de hipótese de tendência e precisão. A investigação mostrou que a qualidade planialtimétrica dos produtos orbitais atendeu aos requisitos para a Classe A (1:100.000) do Padrão de Exatidão Cartográfica brasileiro. Assim, o uso da combinação de informações fornecidas pelos dados PALSAR e SRTM-3 pode ser considerado como uma alternativa promissora para a produção e atualização de mapeamento topográfico de semi-detalhe em ambientes similares da região Amazônica, onde a informação topográfica é ausente ou apresenta baixa qualidade.

Evaluation of the altimetry from SRTM-3 and planimetry from high-resolution PALSAR FBD data for semi-detailed topographic mapping in the Amazon Region.

The Brazilian Amazon has a deficit of 35% of coverage regarding topographic mapping at semi-detailed (1:100,000) scale. This paper presents an alternative to overcome this scenario using a combination of planialtimetric information from two orbital SAR (Synthetic Aperture Radar) missions. The altimetry was acquired from Shuttle Radar Topography Mission (SRTM), while the planimetry was provided from Fine Beam Dual (FBD) images of the Phased Array L-band Synthetic Aperture Radar (PALSAR) sensor. The research was carried out in the mountainous area of the Serra dos Carajás (Pará State), located on the Amazon region. The quality of the orbital topographic information was evaluated regarding precise planialtimetric measurements acquired from Global Positioning System (GPS) field campaigns. The evaluations were performed following two approaches: (1) the use of Root Mean Square Error (RMSE) and (2) tendency and precision hypothesis tests. The investigation has shown that the planialtimetric quality of the orbital products fulfilled the Brazilian Map Accuracy Standards requirements for 1:100,000 A Class map. Thus, the use of combination of information provided by PALSAR and SRTM-3 data can be considered a promising alternative for production and update of semi-detailed topographic mapping in similar environments of the Amazon region, where topographic information is lacking or presents low quality.

Evaluation of the differences between the SRTM and satellite radar altimetry height measurements and the approach taken for the ACE2 GDEM in areas of large disagreement.

The new ACE2 (Altimeter Corrected Elevations 2) Global Digital Elevation Model (GDEM) which has recently been released aims to provide the most accurate GDEM to date. ACE2 was created by synergistically merging the SRTM and altimetry datasets. The comprehensive comparison carried out between the two datasets yielded a myriad of information, with the areas of disagreement providing as much valuable information as the areas of agreement. Analysis of the comparison dataset revealed that certain topographic features displayed consistent differences between the two datasets. The largest differences globally are present over the rainforests, particularly the two largest, around the Amazon and the Congo. The differences range between 10 m and 40 m; these differences can be attributed to the height of the rainforest canopy, as the SRTM returned height values from somewhere within the uppermost reaches of the vegetation whereas the altimeter was able to penetrate through and return true ground heights. The second major class of terrain feature to demonstrate coherent differences are desert regions; here, different deserts present different characteristics. The final area of interest is that of Wetlands; these are areas of special significance because even a slight misrepresentation of the heights can have wide ranging effects in modelling wetland areas. These examples illustrate the valuable additional information content gleaned from the synergistic global combination of the two datasets.

Monitoring and identification of spatiotemporal landscape changes in multiple remote sensing images by using a stratified conditional Latin hypercube sampling approach and geostatistical simulation.

This study develops a stratified conditional Latin hypercube sampling (scLHS) approach for multiple, remotely sensed, normalized difference vegetation index (NDVI) images. The objective is to sample, monitor, and delineate spatiotemporal landscape changes, including spatial heterogeneity and variability, in a given area. The scLHS approach, which is based on the variance quadtree technique (VQT) and the conditional Latin hypercube sampling (cLHS) method, selects samples in order to delineate landscape changes from multiple NDVI images. The images are then mapped for calibration and validation by using sequential Gaussian simulation (SGS) with the scLHS selected samples. Spatial statistical results indicate that in terms of their statistical distribution, spatial distribution, and spatial variation, the statistics and variograms of the scLHS samples resemble those of multiple NDVI images more closely than those of cLHS and VQT samples. Moreover, the accuracy of simulated NDVI images based on SGS with scLHS samples is significantly better than that of simulated NDVI images based on SGS with cLHS samples and VQT samples, respectively. However, the proposed approach efficiently monitors the spatial characteristics of landscape changes, including the statistics, spatial variability, and heterogeneity of NDVI images. In addition, SGS with the scLHS samples effectively reproduces spatial patterns and landscape changes in multiple NDVI images.

Análisis socioeconómico y demográfico de la prevalencia en niños infectados por el virus de la inmunodeficiencia humana por transmisión vertical en la Comunidad de Madrid / A socio-economic and demographic analysis of the prevalence of paediatric HIV due to vertical transmission in the Community of Madrid

España sigue siendo uno de los países con tasas más altas deincidencia del virus de la inmunodeficiencia humana (VIH)/sidaen Europa occidental. La Comunidad de Madrid es la zona másafectada por la infección, con un total de 17.667 casos de sidahasta diciembre de 2008, lo que representa el 23,9% de loscasos registrados en toda España. En dicha comunidad se identificaroncomo áreas básicas de transmisión los distritos delsur y del norte-este, especialmente Usera, Puente de Vallecas,San Blas y Hortaleza, con una mayor prevalencia en el númerode casos de transmisión vertical. También se observó un cambiorespecto al flujo migratorio en los diferentes distritos de laciudad, coincidiendo los distritos con mayor censo de inmigrantescon un registro superior de las tasas de prevalencia de lainfección por el VIH por transmisión vertical. La prevalencia decasos de VIH por transmisión vertical se correlacionó significativamentecon el porcentaje de los inmigrantes (p= –0,544; p=0,011), personas sin estudios (p= 0,487; p= 0,025), mujeres desempleadas(p= 0,477; p= 0,029) y población con una renta percápita baja (p= –0,508; p= 0,019). Por otra parte, cabe pensarque estas zonas sur y norte-este, a su vez, pueden ser franjasimportantes para la propagación de otras enfermedades infecciosas,por lo que la presente memoria podría contribuir aldesarrollo de estrategias efectivas para la educación sobre elVIH, en cuanto a la prevención de situaciones de riesgo(AU)

Spain continues to be one of the countries with the highest HIV/AIDS incidence rates in Western Europe. The Community of Madrid is the area most affected by the infection, with a total of 17,667 cases of AIDS until December 2008, accounting for 23.9% of the cases recorded on a nation level. The south and north-eastern districts of the aforementioned Community, and especially Usera, Puente de Vallecas, San Blas and Hortaleza, were identified as basic transmission areas with a higher prevalence of cases of vertical transmission. A change was also observed with regard to the migration flow in the different districts of the city, with the districts with the highest numbers of immigrants coinciding with those with the highest recorded prevalence rates of cases of vertically transmitted HIV. The prevalence of cases of vertically transmitted HIV was significantly correlated with the percentage of migrants (p= –0.544; p=0.011), people without degrees (p= 0.487; p= 0.025), un employed women (p= 0.477; p= 0.029) and populations with a low per capitain come (p= –0.508; p= 0.019). Moreover, this leads to the thought that these south and north-eastern districts may also be important areas for the spread of other infectious diseases and, therefore, this report may contribute to the development of effective strategies for HIV education as regards the prevention of risk situations (AU)

Modeling hantavirus reservoir species dominance in high seroprevalence areas on the Azuero Peninsula of Panama.

Habitat fragmentation commonly influences distribution of zoonotic disease reservoirs. In Panama, populations of rodent hosts of hantaviruses are favored by small habitat fragments isolated by agricultural lands. We expected a similar relationship between landscape characteristics and host distribution at fine geographical scales in southern Panama. The relative abundance of Zygodontomys brevicauda, the primary host for "Calabazo" virus, and other rodents was assessed at 24 sites within the Azuero Peninsula. We used satellite imagery to produce several spatial variables that described landscape; however, only slope was consistently related to abundances of the two most dominant rodent species. Using regression, we constructed a spatial model of areas of Z. brevicauda dominance, which in turn relates to higher infection rates. The model predicts highest abundances of Z. brevicauda in flat areas, where humans also dominate. These predictions have important ecological and conservation implications that associate diversity loss, topography, and human land use.

An innovative technique in scanning land areas with a multi-FIDLER system.

Remediation can be a long and tedious effort. One possible step in this process is the scanning of land to locate elevated areas of radiological contamination. By adapting existing global positioning technology with radiation detection systems, this process can be significantly accelerated. The Field Instrument for Detecting Low Energy Radiation (FIDLER) was used in conjunction with a Global Positioning System (GPS) and Trimble data logger. With this system two different land areas were scanned using two different scanning methods. In the first method, three FIDLERs were attached to a baby jogger and were used to scan a 20-acre site devoid of vegetation. The second technique involved individuals carrying the instruments over a 15-acre site that contained vegetation. Here the FIDLERs were waved in front of the workers in 50-cm arcs. In all cases, radiological and position data were collected by the data loggers. Using these results, accurate maps were generated for each site clearly illustrating areas and spots of elevated activity. By employing this technique over 250,000 data points pertaining to position and count rate were used to map nearly 40 acres of land in under 3 wk.