148 research outputs found

    Factors Influencing Nest Attendance and Time-activity Budgets of Peregrine Falcons in Interior Alaska

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    An essential prerequisite to examining the impacts of anthropogenic disturbance on avian nesting activities is understanding the intrinsic and extrinsic factors that influence the birds' allocation of time to breeding behaviors. We examined factors influencing nest attendance and time-activity budgets of peregrine falcons (Falco peregrinus anatum) breeding along the Tanana River in Alaska in 1995, 1996, and 1997. First, as is typical of most bird species with nidicolous young and biparental care, females attended the nest more than males and, as the nesting cycle progressed, female attendance decreased to levels similar to those of males. Second, nest area attendance followed a circadian rhythm; parents attended the nest area less during early morning and late evening, which are prime hunting periods, than during late morning. Finally, although females typically performed most of the incubating, the division of labor between males and females during incubation differed among pairs. Higher attendance in the nest area by females during incubation appeared to be associated with more young fledged among successful pairs.Une condition indispensable pour examiner les retombĂ©es de la perturbation anthropique sur la nidification aviaire est reproducteurs. On a Ă©tudiĂ© les facteurs qui ont influencĂ© la prĂ©sence au nid et les budgets temps-activitĂ©s des faucons pĂšlerins (Falco peregrinus anatum) nichant le long de la riviĂšre Tanana en Alaska en 1995, 1996 et 1997. Tout d'abord, comme on doit s'y attendre de la plupart des espĂšces aviaires dont les petits sont nidicoles et oĂč les soins sont biparentaux, les femelles Ă©taient prĂ©sentes au nid plus que les mĂąles et, Ă  mesure que le cycle de nidification avançait, la prĂ©sence des femelles diminuait Ă  des niveaux semblables Ă  ceux de la prĂ©sence des mĂąles. DeuxiĂšmement, la prĂ©sence aux environs du nid suivait un rythme circadien, les parents passant moins de temps prĂšs du nid au dĂ©but de la matinĂ©e et en fin de soirĂ©e - temps forts de la chasse - qu'en fin de et femelles durant l'incubation diffĂ©rait selon les paires. Durant l'incubation, la prĂ©sence plus affirmĂ©e des femelles dans la zone du nid semblait ĂȘtre associĂ©e Ă  un nombre supĂ©rieur de petits qui prenaient leur envol chez les paires qui avaient rĂ©ussi Ă  se reproduire

    Site‐specific weed management—constraints and opportunities for the weed research community: Insights from a workshop

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    The adoption of site‐specific weed management (SSWM) technologies by farmers is not aligned with the scientific achievements in this field. While scientists have demonstrated significant success in real‐time weed identification, phenotyping and accurate weed mapping by using various sensors and platforms, the integration by farmers of SSWM and weed phenotyping tools into weed management protocols is limited. This gap was therefore a central topic of discussion at the most recent workshop of the SSWM Working Group arranged by the European Weed Research Society (EWRS). This insight paper aims to summarise the presentations and discussions of some of the workshop panels and to highlight different aspects of weed identification and spray application that were thought to hinder SSWM adoption. It also aims to share views and thoughts regarding steps that can be taken to facilitate future implementation of SSWM

    Analysis of sex and gender-specific research reveals a common increase in publications and marked differences between disciplines

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    Oertelt-Prigione S, Parol R, Krohn S, Preißner R, Regitz-Zagrosek V. Analysis of sex and gender-specific research reveals a common increase in publications and marked differences between disciplines. BMC Medicine. 2010;8(1): 70.© 2010 Oertelt-Prigione et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Hemodynamic evaluation in patients with transposition of the great arteries after the arterial switch operation: 4D flow and 2D phase contrast cardiovascular magnetic resonance compared with Doppler echocardiography

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    Background: Peak velocity measurements are used to evaluate the significance of stenosis in patients with transposition of the great arteries after the arterial switch operation (TGA after ASO). 4D flow cardiovascular magnetic resonance (CMR) provides 3-directional velocity encoding and full volumetric coverage of the great arteries and may thus improve the hemodynamic evaluation in these patients. The aim of this study was to compare peak velocities measured by 4D flow CMR with 2D phase contrast (PC) CMR and the gold standard Doppler echocardiography (echo) in patients with TGA after ASO. Methods: Nineteen patients (mean age 13 +/- 9 years, range 1-25 years) with TGA after ASO who underwent 2D PC CMR and 4D flow CMR were included in this study. Peak velocities were measured with 4D flow CMR in the aorta and pulmonary arteries and compared to peak velocities measured with 2D PC CMR and Doppler echo. 2D PC CMR data were available in the ascending aorta, main, right and left pulmonary arteries (AAO/MPA/RPA/LPA) for 19/18/ 17/17 scans, respectively, and Doppler echo data were available for 13/9/6/6 scans, respectively. Peak velocities were measured with: 1) a single cross section for 2D PC CMR, 2) velocity maximum intensity projections (MIPs) for 4D flow CMR and 3) Doppler echo. Results: Significantly higher peak velocities were found with 4D flow CMR than 2D PC CMR in the AAO (p = 0.003), MPA (p = 0.002) and RPA (p = 0.005) but not in the LPA (p = 0.200). No difference in peak velocity was found between 4D flow CMR and Doppler echo (p > 0.46) or 2D PC CMR and echo (p > 0.11) for all analyzed vessel segments. Conclusions: 4D flow CMR evaluation of patients with TGA after ASO detected higher peak velocities than 2D PC CMR, indicating the potential of 4D flow CMR to provide improved stenosis assessment in these patients

    Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support

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    Surgical management of tetralogy of Fallot (TOF) results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for many years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced by pulmonary valve replacement the dysfunction might be irreversible. Cardiovascular magnetic resonance (CMR) has evolved during the last 2 decades as the reference standard imaging modality to assess the anatomic and functional sequelae in patients with repaired TOF. This article reviews the pathophysiology of chronic right ventricular volume load after TOF repair and the risks and benefits of pulmonary valve replacement. The CMR techniques used to comprehensively evaluate the patient with repaired TOF are reviewed and the role of CMR in supporting clinical decisions regarding pulmonary valve replacement is discussed
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