Hatching asynchrony and food allocation within broods of Pied-billed Grebes, Podilymbus podiceps

1987 ◽  
Vol 65 (12) ◽  
pp. 2872-2877 ◽  
Author(s):  
Mark R. L. Forbes ◽  
C. Davison Ankney
Keyword(s):  
Prey Size ◽  
Apparent Size ◽  
Food Delivery ◽  
Food Distribution ◽  
Hatching Asynchrony ◽  
Exact Test ◽  
Food Allocation ◽  
Wide Range ◽  
The Mean ◽  
Parental Regulation

Broods of Pied-billed Grebes, Podilymbus podiceps, breeding near Minnedosa, Manitoba (55°16′ N, 99°50′ W), in the summer of 1984, hatched from five to eight eggs over 3–7 days. We found a negative correlation (partial r = −0.56, df = 11, p < 0.05) between the length of the hatching interval and the number of chicks surviving to 35 days of age, after controlling for clutch size. The mean number of sibling aggressions ([Formula: see text], n = 20, 2 SE = 0.4) was higher during foraging bouts with below-average rates of food delivery by parents, as opposed to bouts ([Formula: see text] aggressions, n = 18, 2 SE = 0.2) with above-average rates. Also, larger chicks initiated and won more disputes over positions near adults (Fisher's exact test, p < 0.05, n = 40) than did their smaller sibs. Thus, size hierarchies among siblings influenced food allocation within Pied-billed Grebe broods. Food distribution, however, was nonrandom for 12 of 18 foraging bouts in which there were no apparent size differences between attendant chicks. Signals of hunger status from begging chicks, and parental regulation of which chicks maintained positions near them, also affected food allocation among siblings. Finally, handling times of prey, captured by adults and fed to chicks, depended on brood age (partial r = −0.21, df = 183, p < 0.05) after controlling for prey size. For Pied-billed Grebes, noticeable size hierarchies among chicks remained throughout most of brood development and may have been advantageous during times of low food availability, or may have enabled parents to forage more effectively on a wide range of prey types and sizes.

scholarly journals Group provisioning limits sharing conflict among nestlings in joint-nesting Taiwan yuhinas

2010 ◽  
Vol 6 (3) ◽  
pp. 318-321 ◽  
Author(s):  
Sheng-Feng Shen ◽  
Hsueh-Chen Chen ◽  
Sandra L. Vehrencamp ◽  
Hsiao-Wei Yuan
Keyword(s):  
Cooperative Breeding ◽  
Video Recording ◽  
Food Delivery ◽  
Food Distribution ◽  
Sibling Competition ◽  
Short Intervals ◽  
Food Allocation ◽  
Adult Feeding ◽  
Large Party ◽  
Nestling Begging

Offspring often compete over limited available resources. Such sibling competition may be detrimental to parents both because it entails wasted expenditure and because it allows stronger offspring to obtain a disproportionate share of resources. We studied nestling conflict over food and its resolution in a joint-nesting species of bird, the Taiwan yuhina ( Yuhina brunneiceps ). We show that adult yuhinas coordinate their feeding visits, and that this coordination limits competition among nestlings, leading to a ‘fairer’ division of resources. Transponder identification and video-recording systems were used to observe adult feeding and nestling begging behaviours. We found that: (i) yuhinas feed nestlings more often in large parties than in small parties; (ii) feeding events occurred non-randomly in bouts of very short intervals; and (iii) food distribution among nestlings was more evenly distributed, and fewer nestlings begged, during large-party feeding bouts compared with small-party feeding bouts. To our knowledge, this is the first study in a cooperative breeding species showing that adults can influence food allocation and competition among nestlings by coordinating their feeding visits. Our results confirm the hypothesis that the monopolizability of food affects the intensity of sibling competition, and highlight the importance of understanding the temporal strategies of food delivery.

A Comparison of Physiological Demand between Self-Propelled and Motorized Treadmill Exercise

2018 ◽  
Vol 7 (4) ◽  
pp. 13-21
Author(s):  
Todd Backes ◽  
Charlene Takacs
Keyword(s):  
Respiratory Exchange Ratio ◽  
Treadmill Exercise ◽  
Cardiopulmonary Exercise Testing ◽  
Mean Value ◽  
The Self ◽  
Mixing Chamber ◽  
Wide Range ◽  
The Subject ◽  
The Mean ◽  
Computer Controlled

There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.

The way of value of Correlation of genomic DNA microsatellite loci and live weight of Chukchi reindeer

2020 ◽  
pp. 27-32
Author(s):  
V. Dodokhov ◽  
N. Pavlova ◽  
T. Rumyantseva ◽  
L. Kalashnikova
Keyword(s):  
Microsatellite Markers ◽  
Agricultural Production ◽  
Live Weight ◽  
Biodiversity Loss ◽  
Tribal Community ◽  
High Germination ◽  
Wide Range ◽  
The Mean ◽  
High Level ◽  
Dna Microsatellite

The article presents the genetic characteristic of the Chukchi reindeer breed. The object of the study was of the Chukchi reindeer. In recent years, the number of reindeer of the Chukchi breed has declined sharply. Reduced reindeer numbers could lead to biodiversity loss. The Chukchi breed of deer has good meat qualities, has high germination viability and is adapted in adverse tundra conditions of Yakutia. Herding of the Chukchi breed of deer in Yakutia are engaged only in the Nizhnekolymsky district. There are four generic communities and the largest of which is the agricultural production cooperative of nomadic tribal community «Turvaurgin», which was chosen to assess the genetic processes of breed using microsatellite markers: Rt6, BMS1788, Rt 30, Rt1, Rt9, FCB193, Rt7, BMS745, C 143, Rt24, OheQ, C217, C32, NVHRT16, T40, C276. It was found that microsatellite markers have a wide range of alleles and generally have a high informative value for identifying of genetic differences between animals and groups of animal. The number of identified alleles is one of the indicators of the genetic diversity of the population. The total number of detected alleles was 127. The Chukchi breed of deer is characterized by a high level of heterozygosity, and the random crossing system prevails over inbreeding in the population. On average, there were 7.9 alleles (Na) per locus, and the mean number of effective alleles (Ne) was 4.1. The index of fixation averaged 0.001. The polymorphism index (PIC) ranged from 0.217 to 0.946, with an average of 0.695.

Celiac Disease in Kosovar Albanian Children: Evaluation of Clinical Features and Diagnosis

2020 ◽  
Vol 16 (3) ◽  
pp. 241-247
Author(s):  
Atifete Ramosaj-Morina ◽  
Alije Keka-Sylaj ◽  
Arbana Baloku Zejnullahu ◽  
Lidvana Spahiu ◽  
Virgjina Hasbahta ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Disease Onset ◽  
Clinical Manifestations ◽  
Gastrointestinal Symptoms ◽  
Dominant Mode ◽  
Primary School Children ◽  
Cross Sectional ◽  
Classical Form ◽  
Wide Range ◽  
The Mean

Background: Celiac disease is an immune-mediated disorder characterized by variable clinical manifestations, specific antibodies, HLA-DQ2/DQ8 haplotypes, and enteropathy. Objectives: The aim of this study was to present the clinical spectrum and patterns of celiac disease in Kosovar Albanian children. Methods: A cross-sectional retrospective study was performed with Albanian children aged 0-18 years, treated for celiac disease in the Pediatric Clinic, University Clinical Center of Kosovo from 2005 to 2016. Results: During the study period, 63 children were treated for celiac disease. The mean age at diagnosis was 5.5 years (SD ± 3.31). The mean age at celiac disease onset was 3.3 years (SD ± 2.02), while the mean delay from the first symptoms indicative of celiac disease to diagnosis was 2.2 years (SD ± 2.09). More than 70% of the patients were diagnosed in the first 7 years of life, mainly presented with gastrointestinal symptoms, while primary school children and adolescents mostly showed atypical symptoms (p<0.001). The classical form of celiac disease occurred in 78% of the cases. Sixty (95%) patients carried HLA-DQ2.5, DQ2.2 and/or HLA-DQ8 heterodimers, and only three of them tested negative. Conclusions: Kosovo, as the majority of developing countries, is still facing the classical form of celiac disease as the dominant mode of presentation; as a result, most children with other forms of the celiac disease remain undiagnosed. : Physicians should be aware of the wide range of clinical presentations and utilize low testing thresholds in order to prevent potential long-term problems associated with untreated celiac disease.

scholarly journals Planetary Nebulae in M31: Abundances, and comparison with bright Planetary Nebulae in the LMC

1997 ◽  
Vol 180 ◽  
pp. 475-476
Author(s):  
M. G. Richer ◽  
G. Stasińska ◽  
M. L. McCall
Keyword(s):  
Planetary Nebula ◽  
Luminosity Function ◽  
Large Population ◽  
Wavelength Region ◽  
Planetary Nebulae ◽  
Surprising Result ◽  
Population Synthesis ◽  
Abundance Distribution ◽  
Wide Range ◽  
The Mean

We have obtained spectra of 28 planetary nebulae in the bulge of M31 using the MOS spectrograph at the Canada-France-Hawaii Telescope. Typically, we observed the [O II] λ3727 to He I λ5876 wavelength region at a resolution of approximately 1.6 å/pixel. For 19 of the 21 planetary nebulae whose [OIII]λ5007 luminosities are within 1 mag of the peak of the planetary nebula luminosity function, our oxygen abundances are based upon a measured [OIII]λ4363 intensity, so they are based upon a measured electron temperature. The oxygen abundances cover a wide range, 7.85 dex < 12 + log(O/H) < 9.09 dex, but the mean abundance is surprisingly low, 12 + log(O/H)–8.64 ± 0.32 dex, i.e., roughly half the solar value (Anders & Grevesse 1989). The distribution of oxygen abundances is shown in Figure 1, where the ordinate indicates the number of planetary nebulae with abundances within ±0.1 dex of any point on the x-axis. The dashed line indicates the mean abundance, and the dotted lines indicate the ±1 σ points. The shape of this abundance distribution seems to indicate that the bulge of M31 does not contain a large population of bright, oxygen-rich planetary nebulae. This is a surprising result, for various population synthesis studies (e.g., Bica et al. 1990) have found a mean stellar metallicity approximately 0.2 dex above solar. This 0.5 dex discrepancy leads one to question whether the mean stellar metallicity is as high as the population synthesis results indicate or if such metal-rich stars produce bright planetary nebulae at all. This could be a clue concerning the mechanism responsible for the variation in the number of bright planetary nebulae observed per unit luminosity in different galaxies (e.g., Hui et al. 1993).

scholarly journals Are the First and Second Hip in Staged Bilateral Total Hip Arthroplasty Equal? A Hospital Adverse Event and Perioperative Risk Comparison

2021 ◽  
Author(s):  
Jesus M. Villa ◽  
Tejbir S. Pannu ◽  
Carlos A. Higuera ◽  
Juan C. Suarez ◽  
Preetesh D. Patel ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Adverse Events ◽  
Hip Arthroplasty ◽  
Retrospective Chart Review ◽  
Consecutive Series ◽  
Level Of Evidence ◽  
Exact Test ◽  
Total Hip ◽  
Discharge Disposition ◽  
The Mean

AbstractHospital adverse events remain a significant issue; even “minor events” may lead to increased costs. However, to the best of our knowledge, no previous investigation has compared perioperative events between the first and second hip in staged bilateral total hip arthroplasty (THA). In the current study, we perform such a comparison. A retrospective chart review was performed on a consecutive series of 172 patients (344 hips) who underwent staged bilateral THAs performed by two surgeons at a single institution (2010–2016). Based on chronological order of the staged arthroplasties, two groups were set apart: first-staged THA and second-staged THA. Baseline-demographics, length of stay (LOS), discharge disposition, hospital adverse events, and hospital transfusions were compared between groups. Statistical analyses were performed using independent t-tests, Fisher's exact test, and/or Pearson's chi-squared test. The mean time between staged surgeries was 465 days. There were no significant differences in baseline demographics between first-staged THA and second-staged THA groups (patients were their own controls). The mean LOS was significantly longer in the first-staged THA group than in the second (2.2 vs. 1.8 days; p < 0.001). Discharge (proportion) to a facility other than home was noticeably higher in the first-staged THA group, although not statistically significant (11.0 vs. 7.6%; p = 0.354). The rate of hospital adverse events in the first-staged THA group was almost twice that of the second (37.2 vs. 20.3%; p = 0.001). There were no significant differences in transfusion rates. However, these were consistently better in the second-staged THA group. When compared with the first THA, our findings suggest overall shorter LOS and fewer hospital adverse events following the second. Level of Evidence Level III.

Assessing the Ergonomic Benefits of a New Adjustable Forklift Backrest

2020 ◽  
Vol 64 (1) ◽  
pp. 976-980
Author(s):  
Pranav Madhav Kuber ◽  
Ehsan Rashedi
Keyword(s):  
Comparative Study ◽  
Motion Capture ◽  
Center Of Pressure ◽  
Body Movement ◽  
Pressure Change ◽  
Motion Capture System ◽  
Design Features ◽  
Wide Range ◽  
Body Sizes ◽  
The Mean

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

scholarly journals Correlation and Power Distribution of Intercore Crosstalk Field Components of Polarization-Coupled Weakly Coupled Single-Mode Multicore Fibres

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 191
Author(s):  
José A. P. Morgado ◽  
Adolfo V. T. Cartaxo
Keyword(s):  
Power Distribution ◽  
Communication Systems ◽  
Single Mode ◽  
Coupled Mode ◽  
Weakly Coupled ◽  
Wide Range ◽  
Optical Communication Systems ◽  
The Mean ◽  
Distribution Of Power ◽  
Linear Propagation

The correlation and power distribution of intercore crosstalk (ICXT) field components of weakly coupled multicore fibers (WC-MCFs) are important properties that determine the statistics of the ICXT and ultimately impact the performance of WC-MCF optical communication systems. Using intensive numerical simulation of the coupled mode equations describing ICXT of a single-mode WC-MCF with intracore birefringence and linear propagation, we assess the mean, correlation, and power distribution of the four ICXT field components of unmodulated polarization-coupled homogeneous and quasi-homogeneous WC-MCFs with a single interfering core in a wide range of birefringence conditions and power distribution among the field components at the interfering core input. It is shown that, for homogeneous and quasi-homogeneous WC-MCFs, zero mean uncorrelated ICXT field components with similar power levels are observed for birefringence correlation length and birefringence beat length in the ranges of 0.5m,10m and 0.1m,10m, respectively, regardless of the distribution of power between the four field components at the interfering core input.

SET-VALUED PERFORMANCE APPROXIMATIONS FOR THE QUEUE GIVEN PARTIAL INFORMATION

2020 ◽  
pp. 1-23
Author(s):  
Yan Chen ◽  
Ward Whitt
Keyword(s):  
Steady State ◽  
Decay Rate ◽  
Waiting Time ◽  
Partial Information ◽  
Upper And Lower Bounds ◽  
Interarrival Time ◽  
Limited Information ◽  
Wide Range ◽  
The Mean ◽  
Third Moment

In order to understand queueing performance given only partial information about the model, we propose determining intervals of likely values of performance measures given that limited information. We illustrate this approach for the mean steady-state waiting time in the $GI/GI/K$ queue. We start by specifying the first two moments of the interarrival-time and service-time distributions, and then consider additional information about these underlying distributions, in particular, a third moment and a Laplace transform value. As a theoretical basis, we apply extremal models yielding tight upper and lower bounds on the asymptotic decay rate of the steady-state waiting-time tail probability. We illustrate by constructing the theoretically justified intervals of values for the decay rate and the associated heuristically determined interval of values for the mean waiting times. Without extra information, the extremal models involve two-point distributions, which yield a wide range for the mean. Adding constraints on the third moment and a transform value produces three-point extremal distributions, which significantly reduce the range, producing practical levels of accuracy.

scholarly journals Comparative Study of Flexor Hallicus Longus Tendon Length through Single Incision or Accessory Plantar Medial Incision: A Cadaver Study

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0018
Author(s):  
Caitlin Curtis Crocker ◽  
Eildar Abyar ◽  
Sean Young ◽  
Fatemah Razaghi ◽  
Gerald McGwin ◽  
...  
Keyword(s):  
Single Incision ◽  
Plantar Flexion ◽  
Cadaver Study ◽  
Tendon Graft ◽  
Interference Screw ◽  
Flexor Hallucis Longus ◽  
Tunnel Length ◽  
Exact Test ◽  
Fresh Frozen ◽  
The Mean

Category: Ankle; Hindfoot Introduction/Purpose: Flexor Hallucis Longus (FHL) tendon transfer to the calcaneus is a common adjuvant procedure in the treatment of Achilles pathology. The FHL tendon can be harvested using a posterior incision where the tendon is dissected along its course into the fibroosseous tunnel. Alternatively, the FHL may be harvested through a separate plantar medial incision as it crosses the flexor digitorium longus at the Knot of Henry. This study aims to quantify FHL tendon lengths achieved through the two common approaches utilizing pair matched cadavers. Methods: Seven pair matched fresh-frozen cadaver legs without signs of musculoskeletal abnormalities were used for this assessment. One leg in each pairing underwent a single incision harvest while the contralateral leg underwent an accessory medial plantar harvest. After dissecting the tendon, a calcaneus tunnel was prepared from dorsal to plantar in both calcanei in standard fashion. Two measurements were obtained. The first measurement was taken from the distal aspect of the muscle belly to the distal end of the tendon. The tendon was then pulled through the calcaneus, and the foot was held in tension at 20 degrees of plantar flexion. The second measurement was taken from site where tendon entered the calcaneous to the distal end of the tendon graft. The measurements were analyzed using Wilcoxon Signed Ranks Test and Fischer Exact Test. Results: Using a posterior incision, the mean tendon measurement from calcaneous tunnel to the distal end of the tendon was 4.0 cm. Using an accessory plantar medial incision, the mean tendon measurement from the calcaneous tunnel to the distal end of the tendon was 7.2 cm. The average tunnel length obtained using an accessory medial incision was significantly greater than the length obtained using the single incision approach (p= 0.0003, p=0.0022, and p=0.0016). The accessory plantar medial incision obtained an FHL tendon tunnel length that was an average of 2.9 cm greater than the posterior incision. Conclusion: The single incision approach provided sufficient length to safely anchor the FHL into the calcaneus which suggests that the accessory plantar medial approach is not necessary for routine FHL transfers to the calcaneus with interference screw fixation. However, if additional length is needed for other applications such as posterior tibialis tendon dysfunction or peritoneal tendon tears, the accessory incision does provide an average of 2.9 cm of additional length.

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