Misleading Population Estimates: Biases and Consistency of Visual Surveys and Matrix Modelling in the Endangered Bearded Vulture

Conservation strategies for long-lived vertebrates require accurate estimates of parameters relative to the populations' size, numbers of non-breeding individuals (the “cryptic” fraction of the population) and the age structure. Frequently, visual survey techniques are used to make these estimates but the accuracy of these approaches is questionable, mainly because of the existence of numerous potential biases. Here we compare data on population trends and age structure in a bearded vulture (Gypaetus barbatus) population from visual surveys performed at supplementary feeding stations with data derived from population matrix-modelling approximations. Our results suggest that visual surveys overestimate the number of immature (<2 years old) birds, whereas subadults (3–5 y.o.) and adults (>6 y.o.) were underestimated in comparison with the predictions of a population model using a stable-age distribution. In addition, we found that visual surveys did not provide conclusive information on true variations in the size of the focal population. Our results suggest that although long-term studies (i.e. population matrix modelling based on capture-recapture procedures) are a more time-consuming method, they provide more reliable and robust estimates of population parameters needed in designing and applying conservation strategies. The findings shown here are likely transferable to the management and conservation of other long-lived vertebrate populations that share similar life-history traits and ecological requirements.

Tobacco use and related psychosocial risk factors among youth in urban India: Assessment of Project MYTRI follow-up surveys

Project MYTRI (Mobilizing Youth for Tobacco-Related Initiatives in India) was a large 2-year randomized school-based trial with a goal to reduce and prevent tobacco use among students in 6th and 8th grades in Delhi and Chennai in India (n=32 schools). Baseline analyses in 2004 showed that 6th grade students reported more tobacco use than 8 th grade students, opposite of what is typically observed in developed countries like the US. The present study aims to study differences in tobacco use and psychosocial risk factors between the 6th grade cohort and 8th grade cohort, in a compliant sub-sample of control students that were present at all 3 surveys from 2004-06. Both in 2004 and 2005, 6th grade cohort reported significantly greater prevalence of ever use of all tobacco products (cigarettes, bidis, chewing tobacco, any tobacco). These significant differences in ever use of any tobacco between cohorts were maintained by gender, city and socioeconomic status. The 6th grade cohort also reported significantly greater prevalence of current use of tobacco products (cigarettes, chewing tobacco, any tobacco) in 2004. Similar findings were observed for psychosocial risk factors for tobacco use, where the 6th grade cohort scored higher risk than 8th grade cohort on scales for intentions to smoke or chew tobacco and susceptibility to smoke or chew tobacco in 2004 and 2005, and for knowledge of health effects of tobacco in all three years.^ The evidence of early initiation of tobacco use in our 6th grade cohort in India indicates the need to target prevention programs and other tobacco control measures from a younger age in this setting. With increasing proportions of total deaths and lost DALYs in India being attributable to chronic diseases, addressing tobacco use among younger cohorts is even more critical. Increase in tobacco use among youth is a cause for concern with respect to future burden of chronic disease and tobacco-related mortality in many developing countries. Similarly, epidemiological studies that aim to predict future death and disease burden due to tobacco should address the early age at initiation and increasing prevalence rates among younger populations. ^

Spectral reflectance library of selected biotic and abiotic coral reef features in Glovers Reef, Belize

Underwater spectral reflectance was measured for selected biotic and abiotic coral reef features of Glovers Reef, Belize from March 6 - 10, 2005. Spectral reflectance's of 63 different benthic types were obtained in-situ. An Ocean Optics USB2000 spectrometer was deployed in an custom made underwater housing with a 0.5 m fiber-optic probe mounted next to an artificial light source. Spectral readings were collected with the probe (bear fibre) about 5 cm from the target to ensure that the target would fill the field of view of the fiber optic (FOV diameter ~4.4 cm), as well as to reduce the attenuating effect of the intermediate water (Roelfsema et al., 2006). Spectral readings included for one target included: 1 reading of the covered spectral fibre to correct for instrument noise, 1 reading of spectralon panel mounted on divers wrist to measure incident ambient light, and 8 readings of the target. Spectral reflectance was calculated for each target by first subtracting the instrument noise reading from each other reading. The corrected target readings were then divided by the corrected spectralon reading resulting in spectral reflectance of each target reading. An average target spectral reflectance was calculated by averaging the eight individual spectral reflectance's of the target. If an individual target spectral reflectance was visual considered an outlier, it was not included in the average spectral reflectance calculation. See Roelfsema at al. (2006) for additional info on the methodology of underwater spectra collection.

Narrative of the voyage of H.M.S. Rattlesnake, commanded by the late Captain Owen Stanley during the years 1846-50, including discoveries and surveys in New Guinea, the Louisiade Archipelago, etc : to which is added Mr. E.B. Kennedy's expedition for the exploration of the Cape York Peninsula / by John Macgillivray.

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Experiences Using an Open Source Sofware Library to Teach Computer Vision Subjects

Machine vision is an important subject in computer science and engineering degrees. For laboratory experimentation, it is desirable to have a complete and easy-to-use tool. In this work we present a Java library, oriented to teaching computer vision. We have designed and built the library from the scratch with enfasis on readability and understanding rather than on efficiency. However, the library can also be used for research purposes. JavaVis is an open source Java library, oriented to the teaching of Computer Vision. It consists of a framework with several features that meet its demands. It has been designed to be easy to use: the user does not have to deal with internal structures or graphical interface, and should the student need to add a new algorithm it can be done simply enough. Once we sketch the library, we focus on the experience the student gets using this library in several computer vision courses. Our main goal is to find out whether the students understand what they are doing, that is, find out how much the library helps the student in grasping the basic concepts of computer vision. In the last four years we have conducted surveys to assess how much the students have improved their skills by using this library.

User surveys in ARL libraries /

"Contains the results of a 1994 survey on the use of user surveys by 69 ARL members. This kit focuses on planning, designing, conduction, and analyzing surveys, and incorporating the results into the decision-making process"--SPEC flyer, p. [1].

Secondary Towns Association, formed for the purchasing of one or more special survey or surveys of land in South Australia, for sites for secondary towns. Statement of the proceedings of the directors for the information of the proprietors.

Mode of access: Internet.

Map of the Huron River Valley from Surveys made in 1909 by G. S. Williams. 5123 [Tuttle Hill Road-Harris Road]

Tuttle Hill Road-Harris Road, 1909: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1909 by G. S. Williams. 5122 [Whittaker Road-Huron River Drive]

Whittaker Road-Huron River Drive, 1909: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1908 by G. S. Williams. 5126 [Belleville West]

Belleville West, 1908: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1908 by G. S. Williams. 5125 [Rawsonville East]

Rawsonville East, 1908: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1908 by G. S. Williams. 5124 [Rawsonville West]

Rawsonville West, 1908: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1916 by G. S. Williams. 5134 [Barton Hills], 1916

Barton Hills, 1916: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1908 by G. S. Williams. 5128 [French Landing]

French Landing, 1908: Map of the Huron River Valley