128 research outputs found
Hemodynamic and ocular responses to caloric stimulation and age-related disparities
Age-related declines in vestibular function affect balance and coordination in older adults. Of perhaps equal importance, but less understood, are the potential implications of vestibular degeneration on cardiovascular homeostasis. Recent evidence suggests that the semi-circular canals, a section of the vestibular system, may be involved in the vestibulosympathetic reflex (VSR), but the extent to which the aging of the semi-circular canals interferes with cardiovascular homeostasis is unknown. Activation of the intact VSR results in increases in tonometric blood pressure (TBP) and heart rate (HR) as well as decreases in cardiac output (Q) and pre-ejection period (PEP). The purpose of this investigation was to observe reflexive changes in the VSR and cardiovascular function during activation of the horizontal semi-circular canals using bithermal binaural caloric irrigation in young (n =11; 18-39), middle-aged (n = 7; 40-64), and old (n = 9; 65+) adults and to describe age-related changes in cardiac dynamics in order to identify a possible indicator of disease and/or disease risk. 3x2 repeated measures ANOVAs revealed significant increases in slow-phase velocity for all subjects under all conditions, which indicate adequate excitation of the semi-circular canals to stimulate the VSR; TBP increased in the young and middle-aged groups to a greater degree than the old group; RR-intervals tended to decrease in young adults while either decreasing to a much lesser extent or increasing in the middle-aged and old groups. A decrease in RR-intervals indicates an increase in heart rate, and, thus activation of the VSR. Similarly, sympathovagal balance consistently increased in young participants but not in the old adults. These preliminary results cannot confirm an age-related deterioration in semi-circular canal control of cardiovascular function; however, they are sufficient to underscore the importance of the continued investigation of age-related changes in the VSR
Primary Source Material in Science: The Importance of Archival Field Notes
Field notebooks are a gold mine of unpublished observations, journal notes, sketches, weather reports, specimen lists and travel narratives: these records are primary source data at its most raw and unevaluated. Historical collections of field notes may be the only documentation of a scientist’s thought processes, ideas and observations, particularly if only some of the material was ever published. As part of an IMLS National Leadership grant, the field notes of William Brewster, a highly published ornithologist working during the late 19th and early 20th centuries were digitized and made accessible via the Biodiversity Heritage Library portal. Along with digitizing specimens and other archival materials related to William Brewster, the notebooks allow easy access to his detailed notes and pioneering work in ornithology. The presentation of these notebooks enhances contemporary studies and makes the entire research cycle of this scientist’s work available for analysis by historians of science, scientists, social scientists and humanists or anyone interested in the process of discovery, by creating a richer and more interactive history of science resource. Who knows what ornithological preconceptions might be reconsidered if this body of work is fully available to contemporary researchers and citizen scientists? The purpose of this poster is to demonstrate the connections among Brewster’s field notes, specimens he collected, the publications that were the result of his work and current research, thus making a case for the value of archival research
Regional institutions and the environment in Central and Eastern Europe
AbstractThis contribution is based on a set of reflections presented at the REGov Workshop. These reflections were offered as part of a panel discussion around the topic “Environmental regions in multilevel governance.” Additional presentations provided in the context of this panel discussion include those of Ron Witt, United Nations Environment Programme, and Olivier Graefe, University of Fribourg (this volume). Webcasts of all presentations are available at http://www.reg-observatory.org/outputs.html
Comparison of Heritability Estimates from Daughter on Dam Regression with Three Models to Account for Production Level of Dam
Three models were used to estimate heritabilities for milk yields at different production levels and for different years as twice the regression of daughter residual effects on dam residual effects. The denominator is the residual mean square for dams. The numerator is the difference between the residual term for sum of dam\u27s and daughter\u27s records and sum of residual terms for records of dams and daughters. Model 1 included sire of daughter and herd-year-season of daughters only. Model 2 included sire of daughter, herd-year-season of dam, and herd-year-season of daughter. Model 3 included sire of daughter and herdyear- season of dam and herd-year-season of daughter combination. The weighted mean estimates for each method were, respectively, .35, .38, .38 for milk production and .61, .67, .67 for fat test. Yearly time trends in heritability were slightly positive for both milk production and fat test. Standard errors of heritability estimates from model 1 were 40 to 50% smaller than those from models 2 and 3 due to the smaller number of effects in the model. Estimates for model 2 from low to high production levels averaged .30, .38, .38, and .42 for milk yield and .64, .68, .67, and .71 for fat test
Circle of Willis variations and artery diameter measurements in the Turkish population
Background: The aim of this study was to evaluate the frequency of circle of Willis (COW) variations and the measurements of the COW vessel diameters in the Turkish population.
Materials and methods: The patient population for this single-centre, retrospective study was formed of patients who had brain magnetic resonance angiography (MRA). A total of 384 subjects were included in the study. The three-dimensional time-of-flight (TOF) technique was used for MRA imaging to evaluate the anatomy of the COW. Variations in the COW were recorded. The diameters of the critical arteries of the COW were measured.
Results: Adult configuration of the COW was determined in 326 (85%) cases, foetal configuration in 50 (13%) cases and transitional configuration in 8 (2%) cases. The COW was normal in 328 (85.4%). In the remaining 56 (14.6%) cases, agenesis was determined in 62 vessels. The mean calibrations of the vessels were measured as 2.85 mm in the basilar artery, 4.24 mm in the right internal carotid artery (ICA), 4.32 mm in the left ICA, 1.58 mm in the right A1, 1.64 mm in the left A1, 2.13 mm in the right M1, 2.10 mm in the left M1, 1.80 mm in the right P1, 1.88 mm in the left P1, 1.12 mm in the right posterior communicating artery, and 1.12 mm in the left posterior communicating artery.
Conclusions: Circle of Willis variations may show geographic and ethnic differences. Knowledge of the frequency and types of variation in the population is important for neurosurgeons and in radiological interventional procedures as a guide for entry and in respect of collateral which could develop late
Radiological evaluation of the styloid process length in the normal population
Background: The aim of this study was to evaluate the styloid process (SP) length in the normal population using multidetector computed tomography (MDCT).Materials and methods: In this study, 160 patients who underwent paranasal MDCT between January 2012 and December 2012 were retrospectively evaluated. The patients were divided into groups according to their age and gender: Group 1 age 31–40 years old, 111 subjects; Group 2 age 41–50 years old, 49 subjects; Group A 98 males; Group B 62 females. The mean SP length was calculated from the mean of 2 measurements. SPs were assessed for their average lengths in different gender and age groups. Student’s t-test was used for the comparison of the mean SP lengths between the groups. Differences were considered to be statistically significant at p < 0.05.Results: The mean SP length on both sides varied from 18 to 51 mm (28.4 ± 5.5) in all the patients. The mean SP length was 27.2 ± 5.2 mm in females and 29.2 ± 5.6 mm in males. There was a statistically significant difference between the mean SP lengths in terms of gender (p < 0.028). The mean SP length was 28.5 ± 5.7 mm in Group 1 and 28.2 ± 5.1 mm in Group 2. There was no statistically significant difference between the mean SP lengths in terms of age (p > 0.718).Conclusions: In conclusion, there is still no consensus on the normal values of SP length. Normal values should be determined according to the geographical regions and ethnic groups for the diagnosis of Eagle’s syndrome.
Anthropometric measurements of the orbita and gender prediction with three-dimensional computed tomography images
Background: The aim of the study was to investigate the orbital anthropometric variations in the normal population using three-dimensional computed tomography (3D-CT) images and to define the effects of age and gender on orbital anthropometry.Materials and methods: Three-dimensional orbita CT of 280 patients, obtained for various reasons, were retrospectively evaluated in 772-bed referral and tertiary-care hospital between April 2011 and June 2012. Using 3D images, orbital width, height, biorbital-interorbital diameter and orbital index were measured. Measurements were obtained comparing right and left sides and male to female. The relation of the results with age and gender was analysed.Results: Right orbit was found to be wider than left (p < 0.0001). Male patients had wider (p < 0.0001) and higher (p = 0.0001) orbits. Right orbital index was found to be smaller than the left one (p = 0.005). No differences were found between the genders in terms of right and left orbital indexes (p > 0.05). Biorbital (p < 0.0001) and interorbital (p = 0.01) widths were found to be higher in males. There was no relation between the age change and the parameters defined (p > 0.05).Conclusions: No relation was found between age and orbital measurements. It was concluded that orbital images obtained with 3D-CT may be used as a method for gender evaluation
Maternal serum amyloid A levels in pregnancies complicated with preterm prelabour rupture of membranes
Objective: The aim of the study was to investigate a possible association between maternal serum amyloid A levels (SAA) and maternal and fetal parameters in pregnancies complicated with preterm prelabor rupture of membranes (PPROM). Material and methods: A total of 88 pregnant women (PPROM group, n=44 and control group, n=44) were included into this prospective case control study. Serum blood samples for SAA were obtained from both groups within 1h since the rupture of the membranes and before administration of any medicine. The samples were kept frozen at -70°C until the analysis. The recorded risk factors were: age, gravidity, parity, delivery mode, gender, fetal birth weight, APGAR scores, white blood cell count, microCRP, neutrophil/lymphocyte ratio (NLR), and maternal serum SAA levels. Results: Demographic characteristics showed no statistically significant differences between the groups (p>0.05). The mode of delivery mode was cesarean section: 41% and 43.2% in the study and the control group, respectively, and this difference was statistically significant between the groups (
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