Factors affecting wing molt chronology of female mallards

1991 ◽  
Vol 69 (4) ◽  
pp. 924-928 ◽  
Author(s):  
James O. Leafloor ◽  
C. Davison Ankney
Keyword(s):  
Social Environment ◽  
Positive Relationship ◽  
Anas Platyrhynchos ◽  
Nest Success ◽  
Breeding Period ◽  
Social Environments ◽  
Mortality Factors ◽  
Factors Affecting ◽  
Breeding Seasons

We manipulated nest success of captive mallards (Anas platyrhynchos) during two breeding seasons to determine the effects of different breeding events on the timing of wing molt initiation in females. We also studied the effect of different social environments during the postbreeding period on female wing molt chronology. Late (renesting) brood hens molted their remiges later than did early brood hens in both years of the study. Unsuccessful nesters showed a late, asynchronous wing molt when they molted solitarily, but an early, synchronous wing molt when they were placed together during the postbreeding period. There was a positive relationship between the last date of incubation and the date of wing molt initiation when birds were placed in a group after the breeding period. Social environment appeared to influence the timing of wing molt, particularly among unsuccessful nesters. We discuss the implications of these results in terms of postbreeding mortality factors and potential fall banding bias.

FACTORS AFFECTING THE MORTALITY OF LEAFMINERS ARGYRESTHIA THUIELLA AND PULICALVARIA THUJAELLA (LEPIDOPTERA: YPONOMEUTIDAE AND GELECHIIDAE) ON EASTERN WHITE CEDAR, IN ONTARIO

1979 ◽  
Vol 111 (11) ◽  
pp. 1299-1306 ◽  
Author(s):  
N. L. Bazinet ◽  
M. K. Sears
Keyword(s):  
Host Species ◽  
Life Tables ◽  
Mortality Factors ◽  
Factors Affecting ◽  
White Cedar ◽  
Eastern White Cedar ◽  
Overwintering Mortality

AbstractMortality factors affecting populations of the leafminers Argyresthia thuiella (Pack.) and Pulicalvaria thujaella (Kft.), on eastern white cedar in the area of Guelph, Ontario were identified and summarized in life tables. During the two annual generations studied from 1975 to 1977, overwintering mortality varied widely. Winterkill increased from 6.8% to 62.9% for A. thuiella and from 8.1% to 54.6% for P. thujaella, from 1976 to 1977. Several parasitoids produced substantial mortality of each host species, but their effect may have been superseded by winterkill in 1977. Data indicate that both populations of leafminers increased from 1975 to 1976 but decreased substantially from 1976 to 1977.

scholarly journals Germination, Establishment, and Mortality of Naturally Seeded Southwestern Ponderosa Pine

2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Mineral Soil ◽  
Mortality Data ◽  
Mortality Factors ◽  
Seedling Mortality ◽  
Prescribed Burns ◽  
Factors Affecting ◽  
Northern Arizona ◽  
Lepidopteran Larvae

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.

scholarly journals Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria

2007 ◽  
Vol 97 (5) ◽  
pp. 445-453 ◽  
Author(s):  
S. Girardoz ◽  
R. Tomov ◽  
R. Eschen ◽  
D.L.J. Quicke ◽  
M. Kenis
Keyword(s):  
Leaf Senescence ◽  
Sampling Method ◽  
Plant Defence ◽  
Leaf Miner ◽  
Mortality Factor ◽  
Horse Chestnut ◽  
Mortality Factors ◽  
Grab Sampling ◽  
Defence Reaction ◽  
Factors Affecting

AbstractThe horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miners.

Two Social Environments in a Working Day: Occupation and Spatial Segregation in Metropolitan Tel Aviv

10.1068/a3452 ◽  
2001 ◽  
Vol 33 (10) ◽  
pp. 1765-1784 ◽  
Author(s):  
Orna Blumen ◽  
Iris Zamir
Keyword(s):  
Social Environment ◽  
Spatial Segregation ◽  
Social Environments ◽  
Social Significance ◽  
Tel Aviv ◽  
Blue Collar Workers ◽  
The Social ◽  
White Collar Workers ◽  
Working Day ◽  
And Gender

The concepts of segregation and social distance have long been used to explain the social environment of stratified residential space. However, the social significance of occupation, though acknowledged, has rarely been applied spatially. In this study, we employed these three concepts to examine the social environment of the entire metropolitan employment space as defined by job location. Smallest space analysis was used to identify and compare the sociospatial segregation produced by workers' occupational distribution in employment and residential spheres. This empirical study focused on metropolitan Tel Aviv, Israel's largest urban area, using the latest available national census. Our findings show that the social milieu of employment differed from that of residence: blue-collar workers were segregated from white-collar workers; managers, clerks, and salespersons formed the core group; and gender and ethnic divisions characterised the sociospatial realm of employment. Overall, most employees changed their social environment when they went to work. The study indicates that spatial segregation, within each sphere and between the two spheres, is intrinsic to the capitalist – patriarchal order.

scholarly journals Factors Affecting Business Strategy Implementation of Vietnam Garment Companies

2016 ◽  
Vol 12 (1) ◽  
pp. 133
Author(s):  
Hoang Viet Nguyen ◽  
Duc Nhuan Nguyen
Keyword(s):  
Human Resources ◽  
Corporate Culture ◽  
Business Strategy ◽  
Positive Relationship ◽  
Strategy Implementation ◽  
Point Of View ◽  
Strategy Formulation ◽  
Factors Affecting ◽  
Significant Positive Relationship ◽  
The Impact

This paper studies the impact of factors affecting on business strategy implementation of Vietnam garment companies. A total of 192 questionnaires were administered to respondents chosen from 82 Vietnam garment companies. The findings indicated that there is a significant positive relationship between 05 factors: Strategy formulation-Human resources-Communication-Corporate culture-Organizational structure and business strategy implementation from the sample point of view.

scholarly journals INFLUENCE OF SEASON AND SOCIAL ENVIRONMENT ON THE REPRODUCTIVE-ENDOCRINE STATUS OF THE ADULT LANDRACE BOAR

1990 ◽  
Vol 70 (1) ◽  
pp. 121-128 ◽  
Author(s):  
V. L. TRUDEAU ◽  
L. M. SANFORD
Keyword(s):  
Social Environment ◽  
Late Summer ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Social Environments ◽  
Blood Samples ◽  
Testosterone Secretion ◽  
Endocrine Status ◽  
Reproductive Endocrine ◽  
Basal Concentration

Seasonal variations in LH, FSH, and testosterone secretion were investigated for adult Landrace boars housed in different social environments for 1 yr. Socially nonrestricted boars (n = 4) were penned adjacent to ovariectomized gilts that were hormonally brought into estrus every 2 wk, while socially restricted boars (n = 4) were kept in pens with solid walls. Mean hormone concentrations were determined from the assay of single AM and PM blood samples collected from the jugular vein by venipuncture once a month. In November, February, May and August, blood samples were collected serially over 12 h from jugular catheters for assessment of pulsatile LH and testosterone secretion, and the LH response to a GnRH injection (1 μg kg−1 body weight). Mean LH and testosterone concentrations were relatively high in all boars during the late summer and fall, and often were greater for the socially nonrestricted versus the restricted boars (group × month), P < 0.05) in the winter (December and January). Mean FSH concentration also varied with month (P < 0.05). Pulse analysis indicated that higher mean testosterone concentrations in November and August were the result of increases (month, P < 0.05) in testosterone-pulse frequency and basal concentration. Maximal mean LH concentration in August was associated with maximal (month, P < 0.05) LH-pulse amplitude and basal concentration. The amplitude of the LH peak following GnRH injection increased (P < 0.05) between November and May, and remained high in August. Key words: Gonadotropins, testosterone, blood, season, social environment, boar

scholarly journals Study on the Factors Affecting the Financing of High-Tech SMEs

2017 ◽  
Vol 13 (8) ◽  
pp. 121
Author(s):  
Mingjun Zhu
Keyword(s):  
Positive Relationship ◽  
Significance Test ◽  
High Tech ◽  
Negative Effects ◽  
Factors Affecting ◽  
Enterprise Growth ◽  
Tax Shield ◽  
Debt Tax Shield ◽  
Major Factors ◽  
Tangible Asset

High-tech small and medium-sized enterprises (SMEs) have played an important role in promoting the development of Chinese national economy, but most of them are still facing the difficulty in financing. This paper determines the major factors affecting the financing for high-tech SMEs by using multiple linear regression (MLR) method and significance test then comes to a conclusion that enterprise scale, enterprise growth, tangible asset ratio and equity liquidity have positive relationship with the financing of high-tech SMEs while profitability, accumulation, non-debt tax shield and solvency have negative effects.

scholarly journals Influence of Socially Disadvantaged Environment on Aggressiveness of Pupils at Primary Schools

2018 ◽  
Vol 8 (1) ◽  
pp. 104-115
Author(s):  
Dáša Porubčanová ◽  
Lenka Pasternáková
Keyword(s):  
Primary School ◽  
Social Environment ◽  
School Environment ◽  
Aggressive Behaviour ◽  
Primary Schools ◽  
Social Environments ◽  
Socially Disadvantaged ◽  
Research Findings ◽  
Observation Method ◽  
Aggression Level

AbstractIntroduction: The study deals with occurrence of aggressiveness of pupils from socially disadvantaged environment. It describes the socially disadvantaged environment and the level of aggression of pupils from such environments. The text describes the most important results of the research.Methods: Within the research, a survey was carried out, monitoring the level of aggression of the majority pupils compared to the pupils from socially disadvantaged environment. The survey was carried out personally based on a monitoring scheme of aggression of the pupils from socially disadvantaged environment. The research has been made by direct observation within 60 teaching hours at the level of 1st and 4th grade.Results: The findings, which we have acquired through observation, showed that the age and maturity of younger pupils’ organisms adapts to the model of social environment. Pupils from less stimulating social environments may become the victims of aggressive attacks in various forms more frequently. Types, forms and manifestations of aggression, equally subject to influence of the environment, in a school environment at the level of 10-year-old students are perceived as some form of entertainment. They join the attack on the victim for acceptance or they have the same preferences as the group. It often happens without consequences or attempts to eliminate these signs, because the seriousness of the attack is not ascribed.Discussion: We were interested in the differences of aggression level of the majority pupils compared to the pupils from socially disadvantaged environment in the first and the fourth year of a primary school.Limitations: The results apply only to students in the first level by using of the observation method.Conclusions: As substantial and significant for pedagogic experience, we consider implementing the research findings as well on the higher level of pupils’ education and to define further correlations between aggressive behaviour and socially disadvantaged environment.

Sign in / Sign up

Export Citation Format

Share Document