Statistical power and sea turtle nesting beach surveys: How long and when?

Identifying long-term population trends is essential for the conservation of species of concern. With money and personnel often in short supply, the success of a monitoring program to provide an estimate of population trend requires an efficient survey design that can detect biologically important changes within some prescribed budgetary framework. In this paper we illustrate how costs can be reduced while maintaining an efficient design using a nesting beach survey of female hawksbill sea turtles (Eretmochelys imbricata) in the Eastern Caribbean as a specific example. We compared the statistical power of the current, intensive protocol with those of shorter duration and differing start date to generate general guidelines on sampling. Counts of individual turtles from 1987-2003 were analyzed using Poisson log-linear regression and models with both fixed and random effects describing the temporal variability were explored. We estimate that the current 20 week saturation-tagging survey design could detect a 3% per annum growth with acceptable statistical power (>0.8) in less than 14 years. However, by changing the current survey start date and counting for only 10 weeks, it is possible to detect similar trends with little loss of power while reducing monitoring costs by 25-50%. Our analyses indicate that the statistical power of surveys for hawksbills is influenced by the timing and duration of the survey because of their effect on the proportion of the annual number of nesting females that the survey captures. This simplifies estimating the power of a prospective survey program.     

Determination of carbohydrates in tobacco products by liquid chromatography-mass spectrometry/mass spectrometry: a comparison with ion chromatography and application to product discrimination

Carbohydrates in commercial tobacco products were quantified utilizing a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) technique. The method utilizes negative ion electrospray with multiple reactions monitoring and an internal standard calibration. Snuffs, chewing tobaccos, cigars, and cigarettes were analyzed. Product type differentiation was possible using the carbohydrate levels coupled with pH and moisture contents. The LC-MS/MS method was compared to a method utilizing ion chromatography with pulsed amperometric detection. The LC-MS/MS method provided improved selectivity and specificity, demonstrated better precision, and had a larger dynamic range for glucose, fructose, and sucrose in tobacco extracts.     

Median effective dose of isoflurane, sevoflurane, and desflurane in green iguanas

OBJECTIVE: To determine the median effective dose (ED(50); equivalent to the minimum alveolar concentration [MAC]) of isoflurane, sevoflurane, and desflurane for anesthesia in iguanas. ANIMALS: 6 healthy adult green iguanas. PROCEDURE: In unmedicated iguanas, anesthesia was induced and maintained with each of the 3 volatile drugs administered on separate days according to a Latin square design. Iguanas were endotracheally intubated, mechanically ventilated, and instrumented for cardiovascular and respiratory measurements. During each period of anesthesia, MAC was determined in triplicate. The mean value of 2 consecutive expired anesthetic concentrations, 1 that just permitted and 1 that just prevented gross purposeful movement in response to supramaximal electrical stimulus, and that were not different by more than 15%, was deemed the MAC. RESULTS: Mean +/- SD values for the third MAC determination for isoflurane, sevoflurane, and desflurane were 1.8 +/- 0.3%, 3.1 +/- 1.0%, and 8.9 +/- 2.1% of atmospheric pressure, respectively. The MAC for all inhaled agents was, on average, 22% greater for the first measurement than for the third measurement. CONCLUSIONS AND CLINICAL RELEVANCE: Over time, MACs decreased for all 3 agents. Final MAC measurements were similar to values reported for other species. The decrease in MACs over time may be at least partly explained by limitations of anesthetic uptake and distribution imposed by the reptilian cardiorespiratory system. Hence, for a constant end-tidal anesthetic concentration in an iguana, the plane of anesthesia may deepen over time, which could contribute to increased morbidity during prolonged procedures.     

Knowledge of dietary and behaviour-related determinants of non-communicable disease in urban Senegalese women

OBJECTIVE: To assess knowledge of dietary and behaviour-related determinants of non-communicable disease (NCD) of urban Senegalese women. DESIGN: A cross-sectional, population study using an interviewer-administered knowledge questionnaire, developed and validated for this study. The questionnaire consisted of 24 items with six scores measuring knowledge of: (1) diet- and behaviour-related causes of NCD; (2) diet quality-NCD relationship; (3) fruit and vegetable link with NCD; (4) health consequences of obesity; (5) causes of cardiovascular disease (CVD); and (6) causes of certain cancers. SUBJECTS: A random sample of 301 women aged 20-50 years. RESULTS: The knowledge scores developed suggest that the health consequences of obesity (mean score of 65.4%) were best understood followed by causes of CVD (mean score of 60.6%), because obesity, smoking, high blood cholesterol and dietary fat were well recognised as risk factors for CVD. Subjects scored least for their knowledge of the protective effect of fruit and vegetables (mean score of 19.9%). Knowledge of causes of certain cancers (mean score of 36.1%) was also low. Women who worked outside the home had better knowledge for two scores but otherwise no relationship was found between knowledge and literacy, formal education or body mass index. CONCLUSIONS: Findings suggest reasonable overall knowledge concerning diet and behaviour with NCD, especially given the relatively new context of the obesity epidemic in Senegal. However, there was poor knowledge of the benefit of eating fruit and vegetables and other preventable causes of certain cancers. Education targeting the benefits of vegetables and fruit may have the greatest impact on NCD prevention.     

Grey networks: The contradictory dimensions of Australia's immigration detention system

The notion of dark networks has recently received attention in the literature on policy network analysis. Dark networks are defined as illegal and covert, in contrast to bright networks which are legal and overt. In this article, we suggest a third category – grey networks – which are characterised by their use of secrecy and concealment despite their ostensibly legal status. These networks are subject to contradictory imperatives. They employ methods that cannot be openly acknowledged within the larger legal and social framework in which they function. In this article, we illustrate this concept through an interview‐based study of Australia's immigration detention network. This network enacts a deterrence policy which has been widely condemned as breaching Australia's obligations under international law. At the same time, it is required to maintain a façade of lawfulness and respect for human rights.     

Heritability of agronomic traits correlated with reduced stink bug damage in an F2:3 soybean population derived from IAC-100

In Brazil, some of the most important insect pests causing damage to soybean (Glycine max) are stink bugs. Soybean production would increase if varieties with enhanced resistance were developed. The aim of this work was to examine different traits associated with plant development, and yield-related traits, in an F_2:3 soybean population in a stink bug-infested field and to evaluate genetic parameters and correlations among those traits. The parents and progeny from 229 F₂ plants developed by crossing a resistant cultivar (IAC-100) with a susceptible cultivar (CD-215) were evaluated in three replications in a single environment. Seven agronomic traits and eight indicators of insect resistance were measured. Genotypes showed significant differences for all traits except lodging. The grain-filling period exhibited a positive genotypic correlation of 0.66 with hundred-seed weight, whereas a negative genotypic correlation of ?0.53 was found between pod damage index (%) and weight of healthy seeds. In general, a shorter pod-filling period, lower weight of hundred-seeds, lower indices of pod damage, and higher seed-yield per plant were phenotypic traits of genotypes resistant to these insects.