UAVs in pipeline design and rehabilitation of construction corridors

Surveying techniques used in pipeline construction have evolved slowly. Terrestrial surveying has dominated the industry with surveyors generally using total stations or Real Time Kinematic (RTK) Global Navigation Satellite Systems (GNSS) systems. Newer technology such as Unmanned Aerial Vehicles (UAVs) has been developed and is creating interest in the pipeline construction and pipeline surveying industry. This study compared terrestrial RTK GNSS surveying techniques against new UAV data collection techniques in terms of useability, field accuracy analysis and cost analysis when surveying the same 3.5km section of a 25m wide construction corridor. The study found no significant difference in the accuracies of the UAV surveys compared with those of the traditional RTK GNSS surveying techniques. However the operational costs using the UAV technology were about one third of the more traditional techniques. Moreover there were also significant benefits using UAV technology from workplace health and safety perspectives, from variations from initial planning perspectives, and for resolving post-pipeline disputes between landholders and pipe laying contractors. This study suggests that high resolution aerial orthomosiac imagery, detailed digital surface models (DSM) and high density point clouds all generated from UAV data will become the benchmark for the design and rehabilitation stages of pipeline surveying and construction

Original Article Risk factors for sexually transmitted infections in women in rural Northeast Brazil

Background: Sexually transmitted infections (STIs) are highly prevalent in northeast Brazil, but factors associated with the presence of an STI have rarely been studied systematically. Methodology: We performed a population-based study to assess factors associated with STIs in women of reproductive age (12 to 49 years) in a rural setting in northeast Brazil. A total of 734 women were eligible; 592 (80.7%) had initiated sexual life and were included. Women were examined for the presence of an STI. Socio-economic variables, sexual history, and behaviour were assessed through a structured questionnaire. Laboratory testing included: polymerase chain reaction for human papillomavirus (HPV); ligase chain reaction for Chlamydia trachomatis and Neisseria gonorrhoeae; VDRL and FTA-ABS for Treponema pallidum; analysis of wet mounts, gram stain and Pap smears for Trichomonas vaginalis; and ELISA for HIV. Results: At least one STI was present in 112 (19.6%) of the women. In logistic regression analysis, a previous visit to a Pap smear clinic was protective against an STI (OR=0.26; IC 95%: 0.12-0.57). The following variables were independently associated with STIs: ≥3 partners in life (2.35; 1.32-4.17); first pregnancy <16 years of age (2.28; 1.09-4.78); not knowing if partner had another partner (3.56; 1.09-11.62). Conclusions: The protective and risk factors identified can guide the implementation of gender- and age-specific control programs in rural northeast Brazil. Offering a simple preventive measure (Pap smear collection), usually done by a nurse in thi