Behavioural differences between locally recruiting and dispersing gray squirrels, Sciurus carolinensis

1990 ◽  
Vol 68 (5) ◽  
pp. 935-941 ◽  
Author(s):  
M. Pasitschniak-Arts ◽  
J. F. Bendell
Keyword(s):  
Sex Ratio ◽  
Laboratory Tests ◽  
Population Regulation ◽  
Tail Length ◽  
Sciurus Carolinensis ◽  
Colour Morph ◽  
Resident Population ◽  
Behavioural Type ◽  
Local Recruitment ◽  
Selection Of

We tested the hypothesis that recruitment into a resident population involved the selection of an independently defined behavioural type of animal. Gray squirrels were captured in or shortly after leaving their nests, held in the laboratory in a similar manner, and their behavioural profiles and other properties were determined. The following spring, they were released into the area where most were captured and which we virtually emptied of residents prior to the release. Sixty days following the release, 64% (18/28) of the squirrels had dispersed, most before 10 days, and the remainder recruited and became residents. From the laboratory tests, local recruits compared with dispersers were on average more aggressive. There were no clear differences between the two types in mass, tail length, and sex ratio. All were sexually immature. Recruits were more active than dispersers in December, and activity of both appeared to decline from November to April. Proportionately more of the pepper morph recruited than of the black and gray morphs. There appear to be genetic behavioural and colour morph differences among squirrels that affect or are linked to their local recruitment or dispersal and population regulation.

Selection of effective wax (deposition) inhibitors to oil production and transportation at the Kondinskoye oil field

2020 ◽  
pp. 120-127
Author(s):  
E. N. Skvortsova ◽  
O. P. Deryugina
Keyword(s):  
Laboratory Tests ◽  
Initial Dosage ◽  
Oil Production ◽  
Oil Field ◽  
Transport Systems ◽  
Asphaltene Precipitation ◽  
Wax Deposition ◽  
Selection Of ◽  
Pilot Tests

The article discusses the results of a study on the selection of wax inhibitors that can be used at the Kondinskoye oil field during transportation and dehydration of the emulsion.Asphaltene precipitation is one of the most serious issues in oil production. The experiment was conducted in order to select the most effective wax inhibitors. We have carried out laboratory tests to choose the most effective wax inhibitor in the conditions of oil production, collection, preparation and external transport systems at the Kondinskoye oil field. Based on the data obtained, wax inhibitor-2, wax inhibitor-4, and wax inhibitor-6 have shown the best results in ensuring the efficiency of inhibition, which should be at least 70 %, and, therefore, they can be allowed to pilot tests. The recommended initial dosage of inhibitors according to the results obtained during pilot tests should be at least 500 g/t of oil.

scholarly journals Classifying the Biological Status of Honeybee Workers Using Gas Sensors

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 166
Author(s):  
Jakub T. Wilk ◽  
Beata Bąk ◽  
Piotr Artiemjew ◽  
Jerzy Wilde ◽  
Maciej Siuda
Keyword(s):  
Gas Sensors ◽  
Laboratory Tests ◽  
Test Chamber ◽  
Ambient Air ◽  
True Positive Rate ◽  
True Positive ◽  
Positive Rate ◽  
Parameters Of Accuracy ◽  
Selection Of

Honeybee workers have a specific smell depending on the age of workers and the biological status of the colony. Laboratory tests were carried out at the Department of Apiculture at UWM Olsztyn, using gas sensors installed in two twin prototype multi-sensor detectors. The study aimed to compare the responses of sensors to the odor of old worker bees (3–6 weeks old), young ones (0–1 days old), and those from long-term queenless colonies. From the experimental colonies, 10 samples of 100 workers were taken for each group and placed successively in the research chambers for the duration of the study. Old workers came from outer nest combs, young workers from hatching out brood in an incubator, and laying worker bees from long-term queenless colonies from brood combs (with laying worker bee’s eggs, humped brood, and drones). Each probe was measured for 10 min, and then immediately for another 10 min ambient air was given to regenerate sensors. The results were analyzed using 10 different classifiers. Research has shown that the devices can distinguish between the biological status of bees. The effectiveness of distinguishing between classes, determined by the parameters of accuracy balanced and true positive rate, of 0.763 and 0.742 in the case of the best euclidean.1nn classifier, may be satisfactory in the context of practical beekeeping. Depending on the environment accompanying the tested objects (a type of insert in the test chamber), the introduction of other classifiers as well as baseline correction methods may be considered, while the selection of the appropriate classifier for the task may be of great importance for the effectiveness of the classification.

scholarly journals Mechanical properties of dental restorative materials: relative contribution of laboratory tests

2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Clinical Performance ◽  
Dental Materials ◽  
Correct Selection ◽  
Relative Contribution ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Dental Restorative ◽  
Selection Of

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.

The sex ratio of a gilt’s birth litter can affect her fitness as a breeding female

2018 ◽  
Vol 58 (9) ◽  
pp. 1567 ◽  
Author(s):  
J. Seyfang ◽  
R. N. Kirkwood ◽  
A. J. Tilbrook ◽  
C. R. Ralph
Keyword(s):  
Sex Ratio ◽  
Reproductive Performance ◽  
Reproductive Potential ◽  
Group Housing ◽  
Pork Industry ◽  
Welfare Issue ◽  
Breeding Herd ◽  
Uterine Environment ◽  
Animal Welfare Issue ◽  
Selection Of

Lifetime reproductive performance and behaviour are established in utero driven by genetics and the steroidal milieu of the uterine environment. Developing males synthesise androgens that can be absorbed by females in the litter. Consequently, the proportion of males in a litter has the potential to affect both lifetime reproductive performance and behaviour of female littermates. Although reproductive potential is understandably important for gilt selection, behaviour is becoming progressively more important as group housing of sows increases. Aggression can be a cause for removal from the breeding herd, and can also negatively affect reproductive performance and herd longevity. This review covers existing evidence of masculinisation in rodents and sheep, the mechanism causing masculinisation, and the knowledge gaps surrounding masculinisation in pigs. Premature culling of gilts is an economic and animal welfare issue in the pork industry resulting in low retention of gilts and reduced productivity. The selection of gilts needs to be improved to incorporate both lifetime reproductive potential and behaviour. We determined that there is cause to investigate the effect of the birth litter sex ratio of a gilt on her suitability for selection into the breeding herd.

3 SELECTION OF UNFRAGMENTED-DNA SPERMATOZOA FROM HEAT STRESSED MICE BY FEMALE UTERINE TRACT AND ZONA PELUCIDA BINDING

2009 ◽  
Vol 21 (1) ◽  
pp. 102
Author(s):  
J. D. Hourcade ◽  
M. Perez-Crespo ◽  
B. Pintado ◽  
A. Gutiérrez-Adán
Keyword(s):  
Heat Treatment ◽  
Dna Damage ◽  
Sperm Motility ◽  
Tail Length ◽  
Dna Integrity ◽  
Sperm Selection ◽  
Epididymal Sperm ◽  
Cleavage Rate ◽  
Sperm Dna ◽  
Selection Of

Physiological bases of the sperm selection processes within the female reproductive tract before they meet and fertilize the oocyte are unknown. The aim of this work was to determine if one of the keys of spermatozoa selection could be DNA integrity. It has been reported that sperm DNA damage does not impair in vitro fertilization (IVF). However, it has been suggested that the zona pelucida (ZP) is able to select spermatozoa with unfragmented DNA (Liu and Baker 2007 Hum. Reprod. 22, 1597–1602). In this work, DNA damage of spermatozoa was artificially induced by scrotal heat treatment (HT) (42°C, 30 min). Twenty-one days after the HT, spermatozoa were recovered from the epididymis caudae of CD1 mice and from the uterine horns near the cervix (Uc), from the uterine horns near the oviducts (Uo), and from the oviducts (Ov) of CD1 females 1–2 h after mating with HT and control males. In each region we determined numbers of spermatozoa, individual motility and sperm DNA integrity by COMET assay (% DNA in tail, tail length, and COMET moment was calculated). Also, females naturally mated either with HT or control males were killed at Day 14 of pregnancy, and number of foetuses and resorptions was recorded. Additionally, IVF was performed with epididymal sperm from HT or control males, Two hours after IVF attached and un-attached spermatozoa to the ZP were recovered and samples were evaluated for sperm motility (CASA), sperm zona-binding, and sperm DNA fragmentation (COMET). Also cleavage rate of fertilized oocytes with sperm from HT or control males was analyzed. One-way ANOVA was used to compare the results form each group. Epididymal sperm count (12*106 and 4.4*106 for control and HT respectively), sperm motility (75 and 21% respectively) and testis weight (133.90 and 68.76 mg, respectively) were significantly reduced after heat treatment (P < 0.001). For the heat treatment, COMET values decreased significantly during the transit from Uc to Uo and from Uo to Ov (Tail DNA: 25.7, 23.5, and 14.4% respectively, P < 0.01; Tail length: 38.4, 29.4, and 11.2 pixels, P < 0.001; COMET Moment: 12.5, 8.5, and 2 respectively, P < 0.001). Heat treatment reduced numbers of foetuses (7 ± 0.5 v. 5 ± 0.49, control and HT group, respectively), but number of resorptions was not altered. Spermatozoa bound per ZP in IVF experiments (55 ± 7 and 13 ± 6, control and HT, respectively) and cleavage rate (61 ± 1 v. 15 ± 6, control and HT, respectively) were significantly reduced in the HT group. Two hours after IVF, spermatozoa attached to the ZP in HT group showed a significant decrease in COMET parameters as in tail length (59.46 ± 2.895 v. 34.66 ± 3.531), and in tail moment compared with unattached spermatozoa. Our results indicate that DNA integrity sperm selection mechanisms are present in both the female tract and the ZP. We suggest that genital tract and sperm-ZP binding process plays an important role in selection of sperm with normal chromatin DNA.

Establishment, survival and site selection of the cestode Eubothrium crassum in brown trout, Salmo trutta

Parasitology ◽  
1996 ◽  
Vol 112 (3) ◽  
pp. 347-355 ◽  
Author(s):  
C. R. Kennedy
Keyword(s):  
Population Dynamics ◽  
Site Selection ◽  
Salmo Trutta ◽  
Population Regulation ◽  
Host System ◽  
Mean Intensity ◽  
Density Dependent ◽  
Brown Trout Salmo Trutta ◽  
Selection Of ◽  
Heavy Mortality

SUMMARYPopulation dynamics, site selection, growth and maturation of the cestode Eubothrium crassum in a natural population of Salmo trutta in a small lake were studied over a period of 1 year, the life-span of a cohort in fish. Infection of fish commenced in spring but peaked in July. Small, plerocerciform parasites initially located in the intestine, but then some moved into the pyloric caecae whilst others, the majority in heavy infections, were lost from the fish causing a fall in abundance from 460 to 10 over 2 months. This mortality was density dependent. Initially, parasites were distributed more evenly throughout the caecae but as time increased larger parasites were found preferentially in the anterior caecae before moving back into the intestine when gravid, preparatory to being lost in the following summer. Only a small proportion of the infrapopulation became gravid. Although the proportion of caecae occupied was initially density dependent, by the time of maturation several preferred anterior caecae remained unoccupied and mean intensity always exceeded unity. Neither growth nor maturation was affected by intraspecific competition. It was concluded that caecal availability did not set a limit or threshold of infrapopulation density, and in this respect E. crassum–S. trutta differed from some acanthocephalan-fish systems but was similar to others. Heavy infection followed by heavy mortality appeared to be typical of this parasite-host system in other localities, and of several other cestode-fish systems. The implications of this for population regulation are discussed.

Visual method for evaluating the state of sexual development in male grey squirrels (Sciurus carolinensis)

2006 ◽  
Vol 18 (3) ◽  
pp. 383 ◽  
Author(s):  
Mark Ferryman ◽  
Brenda A. Mayle ◽  
Geoff W. Morgan
Keyword(s):  
Sexual Development ◽  
Population Biology ◽  
Captive Breeding ◽  
Fertility Control ◽  
Sciurus Carolinensis ◽  
High Group ◽  
Visual Method ◽  
Epididymal Spermatozoa ◽  
Grey Squirrels ◽  
Selection Of

Stages of sexual development in grey squirrels were classified by scoring the presence of periscrotal hair and staining, as well as the position, size and colour of testes, to develop a visual breeding score (VBS). The VBS was a highly significant predictor of the presence and concentration of epididymal spermatozoa, which were produced from 12 months of age. Two classes of producers were identified: ‘high’ with spermatozoa levels >10 × 106 mL−1 and ‘low’ with spermatozoa levels <10 × 106 mL−1. Sperm motility was variable across all levels of productive males but was generally higher in the ‘high’ group, indicating that these were ‘functional’ males. Sexual regression was observed in two autumn periods. The VBS was less effective in determining states of regression and redevelopment; the confidence of classification improved when age class (adult or prepubertal) and date of capture was known. The use of the VBS to classify stages of sexual development in grey squirrels will improve selection of animals for studies of population biology and fertility control, and has potential application in captive breeding studies of rare Sciuridae species.

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