732 research outputs found
Differences in the sex and age composition of two muskox populations and implications for male breeding strategies
ATTENTION AND SCHOOL SUCCESS: The Long-Term Implications of Attention for School Success among Low-Income Children
This study examined the longitudinal associations between sustained attention in preschool and children’s school success in later elementary school within a low-income sample (N = 2,403). Specifically, two facets of sustained attention (focused attention and lack of impulsivity) at age 5 were explored as independent predictors of children’s academic and behavioral competence across eight measures at age 9. Overall, the pattern of results indicates specificity between the facets of attention and school success, such that focused attention was primarily predictive of academic outcomes while impulsivity was mainly predictive of behavioral outcomes. Both facets of attention predicted teacher ratings of children’s academic skills and approaches to learning, which suggests that they jointly influence outcomes that span both domains of school success. Patterns of association were similar for children above and below the poverty line. Implications of these findings for interventions targeting school readiness and success among at-risk children are discussed.sustained attention, academic achievement, behavioral competence, low-income children
Associations among Family Environment, Attention, and School Readiness for At-Risk Children
This study examined the developmental pathways from children’s family environment to school readiness within an at-risk sample (N = 1,701). Measures of the family environment (maternal parenting behaviors and maternal mental health) across early childhood were related to children’s observed sustained attention as well as to academic and behavioral outcomes at age 5 years. Results suggest specificity in the associations among attention and its correlates. Maternal parenting behaviors but not mental health explained individual differences in sustained attention, which in turn were associated with variability in children’s academic school readiness. Mediation tests confirmed that sustained attention partially accounted for the link between parenting behaviors and academic school readiness. While maternal mental health was associated with children’s behavioral school readiness, sustained attention did not play a mediating role. Findings indicate sustained attention as a potential target for efforts aimed at enhancing academic school readiness among predominantly poor and minority children.child development, educational success, parenting behaviors, school readiness, mental health
Moccasin Confluence: Occupation and Settlement in the Lower Fredericksburg Basin of the Edwards Plateau
During the summer of 1982 the eastern half of Lyndon B. Johnson State Historical Park was surveyed and sites tested. The work was sponsored by the Texas Parks and Wildlife Department and performed by Center for Archaeological Research and the Division of Behavioral and Cultural Sciences, The University of Texas at San Antonio. The Principal Investigator was Joel D. Gunn. The field work was conducted by the field course in archaeology from the University of Texas at San Antonio. Members (listed in the Acknowledgments section) of the Anthropology Laboratory class assisted the Principal Investigator with laboratory analysis. Most of the sites were shallow or deflated and of limited information value except for their location in the overall settlement pattern. Excavation of 41GL21, Hop Hill (Gunn and Mahula 1977a), was completed. An old stream channel was found in the bedrock under the site. It was filled with occupation debris from the Late Archaic. The site may have been used as an overlook to an adjacent ford in the Pedernales River. At the confluence of the Pedernales River and Williams Creek (Moccasin Confluence) at the east end of the park a very important site was found. Moccasin Confluence consists of two segments divided by Williams Creek. The west segment (41BC71) is a deeply stratified alluvial site with a Holocene sequence. Whether the sequence is continuous through the Holocene remains to be determined. The levels are extremely thick in the Middle and Early Holocene. The location, at three sources of varying sediments, indicates that the site could be a very sensitive geological barometer of Holocene climate, a hypothesis that seems to have merit based on analysis of sediment grain size composition and IPF analysis of sediment chemistry. The site is very rich in chronological diagnostics and is of great potential for studying environmental and cultural process in the Edwards Plateau region. Analysis of artifact wear patterns, points, flake size and frequencies, and mollusks indicates the site was inhabited over long periods of time, sometimes with a fair amount of intensity. Nomads apparently visited the site at the beginning of each cultural period and eventually settled there until their culture was disrupted. The site is recommended for nomination to the National Register of Historic Places. The site (41BC63) on the east bank of Williams Creek outside the park, considered to be the eastern segment of Moccasin Confluence, was tested enough to show that it has a dense burned rock midden. It is assumed to represent a shift of occupation locus to the east side of the creek during the Middle Archaic
Effect of adverse weather on neonatal caribou survival — a review
This paper reviews the relationship between adverse weather and neonatal caribou (Rangifer tarandus spp.) survival in North America by examining the available literature and our own findings. The viewpoint that adverse weather on the calving ground can result in major losses of newborn barren-ground caribou (R. t. groenlandicus) calves is largely unsupported. Published reports of calf mortality caused by adverse weather are questionable because causes of death were rarely determined by postmortem examinations. Circumstantial evidence associated with the small samples of dead calves does not support published assumptions that the mortality was weather related, or that high losses due to adverse weather are common events. The applicability of results from physiological testing are questionable, because the calves were restrained and the behaviour of unrestrained animals was ignored in the conclusions drawn from the tests. The relationship between adverse weather and calf mortality is more speculation than documentation yet often has been uncritically cited. In our view, healthy newborn barren-ground caribou are well adapted physiologically and behaviourally to cope with all but the most severe adverse weather
Traditional behaviour and fidelity to caribou calving grounds by barren-ground caribou
Evidence for the fidelity of female barren-ground caribou (Rangifer tarandus spp.) of each herd to specific calving grounds is convincing. Involvement of learned behaviour in the annual return of those cows to the same calving grounds implies such actions are a form of «traditional» behaviour. Even wide variations in population size have not yet knowingly led to marked changes in size or location of calving grounds or prolonged abandonment of established ones. Rarely is the adoption of new calving grounds reported and emigration to another herd's calving ground or interchange between calving grounds has not yet been unequivocally documented. The calving experience of individual caribou and environmental pressures may modify the cow's use patterns of her calving grounds. The current definition of herds based on traditional calving grounds may require modification, if increasing caribou numbers result in changes in traditions. However, current data do not contradict either the fidelity to traditional calving grounds or the concept of herd identity based on that fidelity
Observations of Barren-Ground Caribou Travelling on Thin Ice during Autumn Migration
In October 1982 we observed the consequences of migrating barren-ground (Rangifer tarandus groenlandicus) encountering lake ice too thin to bear their weight. The observations were made on a portion of taiga winter range of the Beverly caribou herd during autumn migration in the Northwest Territories. We observed caribou hesitating to cross ice that had no snow cover and also saw caribou breaking through ice. Bulls had greater difficulty extricating themselves from the ice water than did relatively light-bodied cows and young individuals. We necropsied one bull that we found dead after it had broken through the ice and remained in the water for more than 20 hours. The bull had died apparently from stress and hypothermia and had heavily traumatized areas on its forelegs and sternum from struggling to break the ice. We could not evaluate the overall extent of injuries and mortalities to caribou from their encounters with thin ice, although we observed signs that at least hundreds had broken through the ice on different lakes.Key words: behaviour, injuries, barren-ground caribou, Rangifer tarandus groenlandicus, thin ice, autumn migration, Northwest TerritoriesMots clés: comportement, blessures, caribou des landes, Rangifer tarandus groenlandicus, glace mince, migration automnale, Territoires du Nord-Oues
Status, population fluctuations and ecological relationships of Peary caribou on the Queen Elizabeth Islands: Implications for their survival
The Peary caribou (Rangifer tarandus pearyi) was recognized as 'Threatened' by the Committee on the Status of Endangered Wildlife in Canada in 1979 and 'Endangered' in 1991. It is the only member of the deer family (Cervidae) found on the Queen Elizabeth Islands (QEI) of the Canadian High Arctic. The Peary caribou is a significant part of the region's biodiversity and a socially important and economically valuable part of Arctic Canada's natural heritage. Recent microsatellite DNA findings indicate that Peary caribou on the QEI are distinct from caribou on the other Arctic Islands beyond the QEI, including Banks Island. This fact must be kept in mind if any translocation of caribou to the QEI is proposed. The subspecies is too gross a level at which to recognize the considerable diversity that exists between Peary caribou on the QEI and divergent caribou on other Canadian Arctic Islands. The Committee on the Status of Endangered Wildlife in Canada should take this considerable diversity among these caribou at below the subspecies classification to mind when assigning conservation divisions (units) to caribou on the Canadian Arctic Islands. In summer 1961, the first and only nearly range-wide aerial survey of Peary caribou yielded a population estimate on the QEI of 25 845, including about 20% calves. There was a strong preference for range on the western QEI (WEQI), where 94% (24 363) of the estimated caribou occurred on only 24% (ca. 97 000 km2) of the collective island-landmass. By summer 1973, the overall number of Peary caribou on the QEI had decreased markedly and was estimated at about 7000 animals. The following winter and spring (1973-74), the Peary caribou population declined 49% on the WQEI. The estimated number dropping to <3000, with no calves seen by us in summer 1974. Based on estimates from several aerial surveys conducted on the WQEI from 1985 to 1987, the number of Peary caribou on the QEI as a whole was judged to be 3300-3600 or only about 13-14% of the 1961 estimate. After a partial recovery in the late 1980s and early 1990s, Peary caribou on the WQEI declined drastically between 1994 and 1997 and were estimated at an all-time known low of about 1100 animals by summer 1997. The number of Peary caribou on the QEI in summer 1997 was likely no more than 2000-2400 or only 8-9% of the 1961 estimate. The four known major die-offs of Peary caribou on the WQEI between 1973 and 1997 occurred during winter and spring periods (1 Sep-21 Jun) with significantly greater (P<0.005) total snowfall, when compared to the long-term mean obtained from 55 caribou-years (1 Jul-30 Jun), 1947/48-2001/02, of weather records from Resolute Airport on Cornwallis Island. Of ecological significance is that the die-offs occurred when the caribou were at low mean overall densities and involved similar high annual rates of loss among muskoxen (Ovibos moschatus). All of the available evidence indicates that Peary caribou (and muskoxen) on the QEI experienced die-offs from prolonged, under-nutrition (starvation) caused by relative unavailability of forage-the forage was there but it was inaccessible to the caribou due to snow and/or ice cover. We cannot control the severe weather that greatly restricts the forage supply but we should try to reduce the losses of Peary caribou from other sources-humans, predators and competitors
Caribou calf deaths from intraspecific strife — a debatable diagnosis
led to the deaths of several newborn barren-ground caribou (Rangifer tarandus groenlandicus) calves within a short period of time and on a small area. This event took place during calving in June 1958 on the calving ground of the Beverly caribou herd in the Northwest Territories. The lack of other examples of multiple deaths of newborn caribou calves from intraspecific strife and our findings on the same calving ground during a study of calf mortality in June 1981, 1982, and 1983 and a study of cow-calf behaviour in June 1981 and 1982 cause us to question the published explanation. As we rarely saw aggressive behaviour among cows and newborn calves that involved actual physical contact and none that resulted in injury or death and because we found instances of multiple killings of calves by wolves {Canis lupus) we suggest that a probable alternative explanation of the 1958 findings is surplus killing by wolves. Most importantly, only direct observation of an event allows separation of a death caused by injuries due to intraspecific strife from a death caused by accidental injuries
Muskox Bull Killed by a Barren-Ground Grizzly Bear, Thelon Game Sanctuary, N.W.T.
The carcass of an adult muskox bull (Ovibos moschatus) killed by a barren-ground grizzly bear (Ursus arctos richardsoni) was found in the Thelon Game Sanctuary. It is suggested that adult muskox bulls along the Thelon River system have become prey for at least some grizzly bears that have learned to ambush them in dense vegetation.Key words: muskoxen (Ovibos moschatus); grizzly bear (Ursus arctos richardsoni); predationMots clés: boeuf musque (ovibos moschatus); ours brun "de la toundra" (Ursus arctos richardsoni); prédateur
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