The annual testicular cycle of the brown-headed cowbird (Molothrus ater)

1968 ◽  
Vol 46 (1) ◽  
pp. 77-87 ◽  
Author(s):  
D. M. Scott ◽  
A. L. A. Middleton
Keyword(s):  
Breeding Season ◽  
Molothrus Ater ◽  
Age Groups ◽  
Egg Laying ◽  
Sperm Production ◽  
Behavioral Differences ◽  
Testicular Regression ◽  
Old Adult ◽  
The Mean ◽  
Two Age Groups

An analysis of the spermatogenic condition and of the weights of testes from about 450 brown-headed cowbirds (Molothrus ater) was made to determine the annual cycle of this species at London, Ontario, and to ascertain variation in the cycle due to age. Testes of birds more than 1 year old (adult) reached maximal weights in late April and early May coincident with the beginning of egg-laying, and about 3 weeks before the testes of 1-year-old birds (yearlings) reached their maximal weight. The mean weights of testes of adults were usually greater, often significantly so, than those of yearlings. From about May 23 to June 23 there were no statistically significant differences in the weights of testes from the two age groups. Beginning in late June, the weights of testes declined rapidly in both age groups and reached a minimum in August. Minimal weights of testes persisted in captive birds until February.Large amounts of sperm were present in the testes of adults in mid-April and of yearlings in late April well in advance of maximal testicular weights. Sperm production occurred in most birds until early July but had ceased in most by late July.Testes, apparently undergoing regression, were noted significantly (p <.005) more frequently in adults than in yearlings in May and early June at the height of the breeding season. The significance of this observation and some aspects of testicular regression, previously unrecorded, are discussed. Adult birds are more sedentary than most yearlings in the breeding season and, unlike the latter, habitually associate with the same female. These behavioral differences may be related to the observed differences between the age groups in the testicular cycle.

Comment on “Three Aspects of Cognitive Development”

1978 ◽  
Vol 46 (1) ◽  
pp. 129-130 ◽  
Author(s):  
William Asher
Keyword(s):  
Cognitive Development ◽  
Experimental Design ◽  
Age Groups ◽  
Quasi Experimental ◽  
The Mean ◽  
Regression Toward The Mean ◽  
Two Age Groups

In Exp. 2 of Siegler's 1976 study a faulty quasi-experimental design was used. The stated results, that older and younger children with apparently equal initial performance derived different benefits from identical experience, can also be explained by a confounding with regression toward the mean. These effects are a result of a selective matching of subjects from two age groups on a fallible variable correlated with age.

scholarly journals Variations in Calcium Use by Birds During the Breeding Season

The Condor ◽  
2001 ◽  
Vol 103 (3) ◽  
pp. 592-598 ◽  
Author(s):  
André A. Dhondt ◽  
Wesley M. Hochachka
Keyword(s):  
Breeding Season ◽  
High Frequency ◽  
Molothrus Ater ◽  
Egg Laying ◽  
Surprising Result ◽  
Very High Frequency ◽  
Cyanocitta Cristata ◽  
Egg Formation ◽  
Calcium Sources ◽  
Very High

Abstract During the breeding season birds need increased amounts of dietary calcium during egg laying and nestling rearing. Passerines acquire calcium shortly before and during laying and do not store calcium for egg formation. Many passerines need to eat extraneous calcium in the form of snail shells or calcareous grit to acquire the element. However, very little is known about variation in the dependency of birds on extraneous calcium, and where this calcium is acquired. Using reports from volunteers who provided extraneous calcium sources at feeder sites across North America we documented that (1) the use of extraneous calcium varied during the breeding season; (2) the location in which species preferentially took the calcium varied with typical feeding location, aside from swallows which, somewhat surprisingly, favored calcium offered on the ground; (3) Brown-headed Cowbirds (Molothrus ater) did not visit calcium sites more often than other blackbirds; (4) calcium use varied among species with thrushes, wrens, and woodpeckers taking calcium only rarely, and swallows, pigeons, and corvids taking calcium frequently. The most surprising result perhaps was the very high frequency of calcium use in jays; Blue Jays (Cyanocitta cristata) may hoard calcium in the fall. Variaciones en el Uso de Calcio por Aves durante la Época Reproductiva Resumen. En la época reproductiva, las aves necesitan incrementar la cantidad de calcio en la dieta durante el período de postura de huevos y cría de los pichones. Las aves paserinas adquieren calcio poco antes y durante la postura y no lo almacenan para la formación de los huevos. Muchas aves paserinas necesitan ingerir calcio de fuentes externas como conchas de caracoles o cascajo calcáreo para adquirir este elemento. Sin embargo, se sabe muy poco sobre la variación en el grado de dependencia de las aves de calcio externo y sobre dónde adquieren este calcio. Con base en reportes de voluntarios que suministraron fuentes externas de calcio en comederos a través de Norteamérica, documentamos que (1) el uso de calcio externo varió durante la época reproductiva; (2) el sitio en donde las especies tomaron el calcio preferencialmente varió de acuerdo al sitio típico de alimentación, con excepción de las golondrinas, que de manera algo sorprendente, prefirieron el calcio ofrecido en el suelo; (3) Molothrus ater no visitó sitios con calcio con más frecuencia que otros ictéridos; (4) el uso de calcio varió entre especies: los túrdidos, troglodítidos y carpinteros muy rara vez tomaron calcio, mientras que las golondrinas, palomas y córvidos lo hicieron frecuentemente. Quizás el resultado más sorprendente fue la muy alta frecuencia de uso de calcio en Cyanocitta; C. cristata podría acumular calcio durante el otoño para uso futuro.

scholarly journals Breeding biology of Bengal eyed turtle Morenia petersi (Anderson 1879) in Bangladesh

2015 ◽  
Vol 42 (2) ◽  
pp. 169-181
Author(s):  
Md Lokman Hossain ◽  
Shorab Uddin Sarker ◽  
Noor Jahan Sarker
Keyword(s):  
Incubation Period ◽  
Clutch Size ◽  
Breeding Season ◽  
Gravid Female ◽  
Gonad Development ◽  
Egg Laying ◽  
Nesting Sites ◽  
Fallow Lands ◽  
The Mean ◽  
Second Clutch

This study was conducted to determine the breeding season, gonad development, egg laying period, clutch size and other biological aspects of Bengal Eyed Turtle, Morenia petersi of Bangladesh. The egg-laying period was found between November and February. The nesting sites were elevated fallow lands in secluded areas. The female turtle laid all the mature eggs at a time for each clutch at night. A gravid female turtle laid two clutches of eggs in each breeding season and the mean clutch size was 9.7 ± 1.5 eggs and mean weight of each egg was 8.9 ± 1.3 g. The eggs are elongated in shape and whitish in colour. The mean incubation period was 119 ± 30 days. The incubation period of first clutch was the longer than the second clutch. The hatchlings emerged out between April and May. Hatchery success was found 56.8%. The percentage of weight gain and specific growth rate (SGR) by weight of hatchlings in the first year was greater than second and third year. Present investigation was made to explore the possibility to raise turtle farming in captive condition.Bangladesh J. Zool. 42(2): 169-181, 2014

Influence of Age, Time, and Peritonitis on Peritoneal Transport Kinetics in Children

1998 ◽  
Vol 18 (6) ◽  
pp. 590-597 ◽  
Author(s):  
Tuula M. Hölttä ◽  
Kai A.R. Rönnholm ◽  
Christer Holmberg
Keyword(s):  
Age Groups ◽  
Potassium Phosphate ◽  
Transport Kinetics ◽  
Membrane Function ◽  
Peritoneal Transport ◽  
Fill Volume ◽  
The Mean ◽  
A Prospective Study ◽  
Age Independent ◽  
Two Age Groups

Objective To evaluate peritoneal transport kinetics and its changes over time in children with and without peritonitis, and to record possible differences between children under and over 5.0 years of age. Design A prospective study. The patients underwent a 4hour peritoneal equilibration test (PET) comprising 2.27% dextrose with a dialysate fill volume of 1000 mL/m2 of body surface area (BSA), at baseline and after a mean of 0.8: I: 0.4 years of uninterrupted dialysis. Patients We investigated 28 patients on maintenance peritoneal dialysis at baseline; 10 were under 5.0 years of age. The final PET was performed in 21 patients. Main Outcome Measures Peritoneal equilibration rates for urea (U), creatinine (C), glucose (G), sodium, potassium, phosphate, and albumin (A) were measured. Initial and final peritoneal equilibration rates were compared. Mass transfer area coefficients (MTAC) were calculated for urea, creatinine, glucose, and albumin. Residual dialysate volume was determined. Results Median age at first PET was 7.6 years (range 0.3 -16.6 yr). The mean (±1 SD) 4-hour dialysate-to-plasma (DIP) ratios for U, C, and A were 0.92:1: 0.05,0.70 ± 0.12, and 0.014: I: 0.007, respectively. The mean 4-hour DIDo ratio for G was 0.32: I: 0.10. DIP and DIDo results were similar in the two age groups, and peritoneal membrane function remained stable over the study period. Mean MTAC (:1:1 SD) values were: U, 22.3: I: 4.8; C, 10.9: I: 4.1; G, 11.1: I: 3.3; and A, 0.07: I: 0.03. MTAC data were similar in the two age groups and no significant changes occurred during the study period. Conclusions When the volume tested in children is proportional to BSA, the solute DIP ratios seem to be age-independent. Our data provide evidence that in pediatric patients MTAC is also age-independent.

scholarly journals Appendicitis in Children: Evaluation of the Pediatric Appendicitis Score in Younger and Older Children

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Martin Salö ◽  
Gustav Friman ◽  
Pernilla Stenström ◽  
Bodil Ohlsson ◽  
Einar Arnbjörnsson
Keyword(s):  
Diagnostic Delay ◽  
Age Groups ◽  
Lower Sensitivity ◽  
Older Children ◽  
Suspected Appendicitis ◽  
Abdominal Examination ◽  
The Mean ◽  
Low Sensitivity ◽  
Appendicitis Score ◽  
Two Age Groups

Background. This study aimed to evaluate Pediatric Appendicitis Score (PAS), diagnostic delay, and factors responsible for possible late diagnosis in children <4 years compared with older children who were operated on for suspected appendicitis.Method. 122 children, between 1 and 14 years, operated on with appendectomy for suspected appendicitis, were retrospectively analyzed. The cohort was divided into two age groups: ≥4 years (n=102) and <4 years (n=20).Results. The mean PAS was lower among the younger compared with the older patients (5.3 and 6.6, resp.;P=0.005), despite the fact that younger children had more severe appendicitis (75.0% and 33.3%, resp.;P=0.001). PAS had low sensitivity in both groups, with a significantly lower sensitivity among the younger patients. Parent and doctor delay were confirmed in children <4 years of age with appendicitis. PAS did not aid in patients with doctor delay. Parameters in patient history, symptoms, and abdominal examination were more diffuse in younger children.Conclusion. PAS should be used with caution when examining children younger than 4 years of age. Diffuse symptoms in younger children with acute appendicitis lead to delay and to later diagnosis and more complicated appendicitis.

Efficacy of a 12-Hour Sustained-Release Preparation in Maintaining Therapeutic Serum Theophylline Levels in Asthmatic Children

PEDIATRICS ◽  
1980 ◽  
Vol 66 (1) ◽  
pp. 97-102
Author(s):  
H. William Kelly ◽  
Shirley Murphy
Keyword(s):  
Sustained Release ◽  
Age Groups ◽  
Serum Theophylline ◽  
Asthmatic Children ◽  
Theophylline Level ◽  
Serum Theophylline Level ◽  
Significant Difference ◽  
Sustained Release Theophylline ◽  
The Mean ◽  
Two Age Groups

The purpose of this study was to determine whether a new sustained-release theophylline preparation TheoDur could maintain therapeutic serum theophylline levels in asthmatic children on a 12-hour dosage regimen. Twenty asthmatic children aged 6 to 18 years with a mean of 11.4 years who required continuous theophylline therapy for control of their asthma were enrolled in the study. Each patient's dosage was titrated to achieve a six-hour postdose serum theophylline level between 10 and 20 µg/ml. The patients required a mean ± SEM dose of 10.0 ± 0.54 mg/kg every 12 hours which gave a mean ± SEM six-hour postdose serum theophylline level of 15.65 ± 0.72 µg/ml. At the end of five days on this dosage, the patients were admitted and serum theophylline levels were determined every three hours for 24 hours. The mean ± SEM difference between maximum and minimum serum theophylline levels (ΔTL) for the group was 4.5 ± 0.3 µg/ml. There was not a significant difference in the ΔTL between the two age groups (6 to 9 years, 4.5 ± 0.5 µg/ml and 10 to 18 years 4.5 ± 0.4 µg/ml). In conclusion, TheoDur will maintain therapeutic serum theophylline levels with minimal fluctuations in asthmatic children on a 12-hour dosing schedule.

Retest Reliability of the Wechsler Adult Intelligence Scale-Revised for 18- to 19-Year-Olds

1996 ◽  
Vol 78 (1) ◽  
pp. 211-214 ◽  
Author(s):  
Howard Carvajal ◽  
Matthew S. Schrader ◽  
Cooper B. Holmes
Keyword(s):  
Age Groups ◽  
Adult Intelligence Scale ◽  
Intelligence Scale ◽  
Retest Reliability ◽  
Wechsler Adult Intelligence Scale ◽  
Adult Intelligence ◽  
The Mean ◽  
Wechsler Adult Intelligence ◽  
Two Age Groups

Retest reliability of the WAIS-R for 18- to 19-yr.-olds was estimated for 44 undergraduates who took the test twice with 2 to 8 weeks between testings. The mean scores on subtests and IQs and the correlations of subtest scores and IQs were similar to the values obtained by Wechsler in 1981 with only two age groups, 25- to 34- and 45- to 54-yr.-old examinees.

scholarly journals Immunoglobulin G1 and G2 profile in children with Down syndrome

2017 ◽  
Vol 11 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Supti Prava Saha ◽  
Monsura Khan ◽  
Ashesh Kumar Chowdhury
Keyword(s):  
Down Syndrome ◽  
Age Groups ◽  
Recurrent Infection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Children ◽  
Normal Children ◽  
Children With Down Syndrome ◽  
Healthy Control ◽  
The Mean ◽  
Two Age Groups

Background and objectives: It is well known that children with Down syndrome (DS) suffer from frequent infections. There is an association of certain IgG subclass abnormalities with the predisposition to recurrent infection of the respiratory tract. Therefore, the study was conducted to determine the immunoglobulin G1 and G2 (IgG1, IgG2) profile in children with DS.Material and methods: Forty children between the ages of 6 months to 12 years with DS (47 XX/XY, +21) attending the Department of Immunology, BIRDEM were enrolled in the study. Age and sex matched 30 healthy normal children with 46 XX/XY were included as control. Enrolled DS and healthy children were divided into two age groups namely 6 months to 6 years and 7 years to 12 years. Serum IgG1 and IgG2 concentrations were determined by enzyme linked immunosorbent assay (ELISA) method.Results: The mean serum IgG1 concentrations of children with DS in both age groups did not differ significantly from that of normal healthy children. But the IgG2 level was significantly less (p<0.003 and p<0.004) in both age groups of children with DS compared to that of control healthy children.Conclusion: The study has demonstrated that the serum IgG2 level was significantly less in children with DS than that of matched normal healthy control children while there was no deficiency of IgG1.IMC J Med Sci 2017; 11(1): 1-4

scholarly journals Sexual behaviors: study in the youth

2018 ◽  
Vol 16 (3) ◽  
Author(s):  
Patrícia Sofia Ferreira Miranda ◽  
Joana Margarida Gonçalves Aquino ◽  
Ricardo Miguel Patrício de Carvalho Monteiro ◽  
Maria dos Anjos Coelho Rodrigues Dixe ◽  
Alexandra Maria Branco da Luz ◽  
...  
Keyword(s):  
Sexual Intercourse ◽  
Sexual Behaviors ◽  
Contraceptive Method ◽  
Emergency Contraception ◽  
Age Groups ◽  
World Health ◽  
First Sexual Intercourse ◽  
The Mean ◽  
Health Organization ◽  
Two Age Groups

ABSTRACT Objective: To characterize sexual behaviors in a sample of adolescents and youth. Methods: An analytical descriptive study using a questionnaire about sexual behaviors, adapted from the World Health Organization. It was distributed to students from a Portuguese city aged 14-24 years, during two months. Two age groups were defined: G1 - students aged 14-19 years; G2 - aged 20-24 years. Results: The sample included 2,369 students, 61% females and 70% in G1. The mean age of first sexual intercourse was 16.4±1.8 years; 93% used some contraceptive method in the first sexual intercourse. Out of those who did not use contraception in the first sexual intercourse, 83% were in G1 (p<0.001). Emergency contraception was used at least once by 54% (63% in G2, p<0.001). Among those who had unprotected sexual intercourses, 9% were under the influence of alcohol, 53.6% were female and 53.4% were in G2 (p<0.001). Homosexual contacts occurred in 21% of cases; in that, 62% in G1 and 84% among females (p<0.001). Conclusion: The use of contraceptionin the first sexual intercourse was common in our sample. However, the number of adolescents not using any contraceptive method in subsequent sexual intercourses, and the high percentage of them who consider it unnecessary, are a concern. Unprotected sexual intercourses, as well as unplanned intercourses and under influence of alcohol or drugs, especially in the youngest, urge the need for intervention regarding sexual education.

The effect of age and sex on glycated hemoglobin in dogs

2021 ◽  
pp. 104063872110650
Author(s):  
Ioannis L. Oikonomidis ◽  
Theodora K. Tsouloufi ◽  
Maria Kritsepi-Konstantinou ◽  
Nectarios Soubasis
Keyword(s):  
Capillary Electrophoresis ◽  
Glycated Hemoglobin ◽  
Age Groups ◽  
Blood Samples ◽  
Health Checks ◽  
Old Adult ◽  
The Mean ◽  
Effect Of Age ◽  
Edta Blood ◽  
Age And Sex

We investigated the effect of age and sex on canine glycated hemoglobin (HbA1c) using a validated capillary electrophoresis assay. Aliquots of EDTA blood samples collected for routine health checks were used. HbA1c was measured using the Capillarys 2 flex-piercing system (Sebia). We included 58 clinically and hematologically healthy, normoglycemic dogs (29 males, 29 females), allocated to 3 age groups: young (14 dogs <1-y-old), adult (31 dogs 1–7.9-y-old), and senior (13 dogs ≥8-y-old). The mean (± SD) HbA1c was not significantly different ( p = 0.428) between the age groups (young: 1.68 ± 0.54%; adult: 1.59 ± 0.41%; senior: 1.80 ± 0.57%). The HbA1c was not significantly correlated with age (rho = 0.144, p = 0.280). The median (range) HbA1c was not significantly different ( p = 0.391) between male [1.7% (0.5–2.5%)] and female [1.5% (1.0–2.7%)] dogs. Age and sex do not appear to affect canine HbA1c; however, a study of geriatric dogs would be needed to fully exclude an effect of age on HbA1c.

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