Changes In Biometrics Research Articles

Changes in migration phenology and biometrical traits of Reed, Marsh and Sedge Warblers

Abstract Global environmental processes like climate change could severely affect population level migratory behaviour of long range migrant birds. We analyzed changes in migration phenology and biometrics of three closely-related long-distance migrant Acrocephalus species. We used the records of 12 063 Sedge, 12 913 Reed, and 5 409 Marsh Warblers caught and ringed between 1989–2009, at a Hungarian stopover site. Quantile regressions were used to analyse the changes in spring and autumn migration phenology. Median spring arrival date of Sedge and Reed Warblers shifted 6.5 and 7.5 days earlier, respectively. Autumn arrival of all species shifted one (Reed and Marsh Warblers) or two (Sedge Warbler) weeks later. Mean body mass of adult Reed and Marsh Warblers decreased in spring (by 0.3 and 0.2 grams, respectively) and in autumn (by 0.8 and 0.2 grams, respectively) while body mass of adult Sedge Warblers decreased only in autumn (by 0.4 grams). Mean wing length of all species increased significantly (range of change: 0.6–1 mm). Despite the fact that the studied species are closely related, all three have remarkably different migration strategies. However, similar patterns can be observed in the studied parameters, indicating that global processes may have general effects on these species, albeit through markedly different mechanisms.

Effect of intensive insulin therapy on macular biometrics, plasma VEGF and its soluble receptor in newly diagnosed diabetic patients

To evaluate whether intensive insulin therapy leads to changes in macular biometrics (volume and thickness) in newly diagnosed diabetic patients with acute hyperglycaemia and its relationship with serum levels of vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1). Twenty-six newly diagnosed diabetic patients admitted to our hospital to initiate intensive insulin treatment were prospectively recruited. Examinations were performed on admission (day 1) and during follow-up (days 3, 10 and 21) and included a questionnaire regarding the presence of blurred vision, standardized refraction measurements and optical coherence tomography. Plasma VEGF and sFlt-1 were assessed by ELISA at baseline and during follow-up. At study entry seven patients (26.9%) complained of blurred vision and five (19.2%) developed burred vision during follow-up. Macular volume and thickness increased significantly (p = 0.008 and p = 0.04, respectively) in the group with blurred vision at day 3 and returned to the baseline value at 10 days. This pattern was present in 18 out of the 24 eyes from patients with blurred vision. By contrast, macular biometrics remained unchanged in the group without blurred vision. We did not detect any significant changes in VEGF levels during follow-up. By contrast, a significant reduction of sFlt-1 was observed in those patients with blurred vision at day 3 (p = 0.03) with normalization by day 10. Diabetic patients with blurred vision after starting insulin therapy present a significant transient increase in macular biometrics which is associated with a decrease in circulating sFlt-1.

Application of the Environmental Assessment Tool (EAT) as a Process Measure for a Worksite Weight Management Intervention

To assess the ability of the Environmental Assessment Tool (EAT) to detect changes over time in workplace physical and social environmental supports for physical activity and nutrition; and predict employee engagement, behavior changes, and biometrics. Analyses utilized site-level (n = 12) EAT scores. Differences-in-difference regressions tested changes in EAT scores over time across treatment sites. Generalized linear mixed models examined the ability of site-level EAT scores to predict individual-level outcomes. Overall, the EAT captured changes in the workplace environmental supports for health promotion over time. However, the ability of EAT scores to predict intervention outcomes was weak. The EAT is a useful tool for monitoring changes in workplace environments over time. Further research is needed regarding the dose or intensity of environmental intervention needed to affect changes in employee behaviors and biometrics.

Different timing of autumn migration of two Ringed Plover Charadrius hiaticula subspecies through the southern Baltic revealed by biometric analysis

Ringed Plovers were trapped in Puck Bay (southern Baltic) between 1983 and 2002 during autumn migration. In adults a clear decrease of mean wing and bill lengths occurred between the third decade (ten‐day period) of July and the first decade of August. A similar pattern was observed in juvenile wing lengths, whereas a sharp decline in mean bill length occurred later, between the second and the third decade of August. These changes in biometrics suggested that the larger birds passing through the study area in July belonged to the hiaticula subspecies and late migrants (adults caught from the beginning of August and juveniles caught from the third decade of August) were of the tundrae subspecies. This was supported by comparison of mean measurements of these early and late migrants passing through Puck Bay with data from other areas where only either hiaticula or tundrae occur. These data were used to compare the biometrics of adults and juveniles of each subspecies.

Seasonal and long‐term changes in biometrics of eel larvae: a possible relationship between recruitment variation and North Atlantic ecosystem productivity

The European eel larval life has two stages: the oceanic leptocephalus, in which growth is dependent on food supply, and the metamorphosis glass eel stage, in which feeding and growth are stopped until immigration in estuarine waters. Data from fisheries and experimental surveys in European estuaries at different periods between the 1930s and the 1990s showed a simultaneous decrease of mean length and abundance level. A monthly survey at the Vilaine estuary (Bay of Biscay) during 2 years provided a periodical model of seasonal variation in length and weight of newly recruited glass eels. Otolith microstructure was used to back‐calculate larval stage durations and the timing of transatlantic migration. Glass eels entering the estuary in autumn are longer and more numerous than those arriving in summer. They migrated across the ocean during spring and summer, seasons when plankton production is likely to reach maximum levels. The proposed hypothesis regarding the determinism of recruitment in the eel, on the seasonal and on the yearly range, is that leptocephalus growth and glass eel survival are partly dependent on the plankton production at the oceanic scale. Eel recruitment dynamics could provide an integrated figure of large‐scale environment fluctuations.