Miami University, Ohio
Not a member yet
805 research outputs found
Sort by
Using Matched Samples to Look for Sex Differences
Get PDFThe reasons for observed differences in physics performance between men and
women have yet to be clearly determined. This study asks the question: if men
and women have a similar background at the start of an introductory physics
course, will there be differences in how much physics they learn by the end of the
course? To answer the question, a matched sample of men and women was
studied. Statistical analysis of the post-tests reveals no significant differences
between the men and women in the matched sample
Physiological Ecology of Overwintering in the Hatchling Painted Turtle: Multiple-Scale Variation in response to Environmental Stress
Get PDFWe integrates field and laboratory studies in an investigation of water balance, energy use, and mechanisms of cold-hardiness in hatchling painted turtles (Chrysemys picta) indigenous to west-central Nebraska (Chrysemys picta bellii) and northern Indiana (Chrysemys picta marginata) during the winters of 1999-2000 and 2000-2001. We examined 184 nests, 80 of which provided the hatchlings (n=580) and or samples of soil used in laboratory analysis. Whereas winter 1999-2000 was relatively dry and mild, the following winter was wet and cold; serendipitously, the contrast illuminated a marked plasticity in physiological response to environmental stress. Physiological and cold‐hardiness responses of turtles also varied between study locales, largely owing to differences in precipitation and edaphics and the lower prevailing and minimum nest temperatures (to −13.2°C) encountered by Nebraska turtles. In Nebraska, winter mortality occurred within 12.5% (1999–2000) and 42.3% (2000–2001) of the sampled nests; no turtles died in the Indiana nests. Laboratory studies of the mechanisms of cold‐hardiness used by hatchling C. picta showed that resistance to inoculative freezing and capacity for freeze tolerance increased as winter approached. However, the level of inoculation resistance strongly depended on the physical characteristics of nest soil, as well as its moisture content, which varied seasonally. Risk of inoculative freezing (and mortality) was greatest in midwinter when nest temperatures were lowest and soil moisture and activity of constituent organic ice nuclei were highest. Water balance in overwintering hatchlings was closely linked to dynamics of precipitation and soil moisture, whereas energy use and the size of the energy reserve available to hatchlings in spring depended on the winter thermal regime. Acute chilling resulted in hyperglycemia and hyperlactemia, which persisted throughout winter; this response may be cryoprotective. Some physiological characteristics and cold‐hardiness attributes varied between years, between study sites, among nests at the same site, and among siblings sharing nests. Such variation may reflect adaptive phenotypic plasticity, maternal or paternal influence on an individual’s response to environmental challenge, or a combination of these factors. Some evidence suggests that life‐history traits, such as clutch size and body size, have been shaped by constraints imposed by the harsh winter environment
Postfreeze reduction of locomotor endurance in the freeze-tolerant wood frog, Rana sylvatica.
Get PDFConsiderable study has focused on the physiological adaptations for freeze tolerance in the wood frog, Rana sylvatica, a northern species that overwinters within the frost zone, but little attention has been paid to the associated costs to organismal performance. Here we report that freezing causes transient impairment of locomotor endurance and adverse changes in exercise physiology that persist for at least 96 h. Wood frogs frozen at −2°C for 36 h exhibited normal behaviors and hydro‐osmotic status and near‐normal metabolite (glycogen, glucose, and lactate) levels within 24 h after thawing began. However, when exercised to exhaustion on a treadmill, these frogs showed a 40% reduction in endurance as compared to sham‐treated (unfrozen) controls, a reduction that persisted for at least 96 h. Previously frozen frogs exhibited higher rates of lactate accumulation during exercise than controls, suggesting that prior freezing forces greater reliance on the glycolytic pathways of energy production to support exercise. Given that this species breeds in late winter, when subzero temperatures are common, freezing may result in reduced fitness by hampering their ability to reach the pond, avoid predators, and successfully obtain mates
Cold-hardiness and evaporative water loss in hatchling turtles.
Get PDFNorth American turtles hatch in late summer and spend their first winter either on land or underwater. Adaptations for terrestrial overwintering of hatchlings in northern regions, where winter thermal and hydric regimes are harsh, have not been systematically investigated in many species. We measured intrinsic supercooling capacity, resistance to inoculative freezing, and desiccation resistance in hatchlings of terrestrial and aquatic turtles collected from northern (Terrapene ornata, Chrysemys picta bellii, Kinosternon flavescens, Chelydra serpentina) and southern (Chrysemys picta dorsalis, Trachemys scripta, Sternotherus odoratus, Sternotherus carinatus) locales. Supercooling capacity was estimated from the crystallization temperature of turtles cooled in the absence of external ice nuclei. Mean values ranged from −8.1° to −15.5°C and tended to be lower in terrestrial hibernators. Inoculation resistance was estimated from the crystallization temperature of turtles cooled in a matrix of frozen soil. These values (range of means: −0.8° to −13.6°C) also tended to be lower in the terrestrial hibernators, especially C. picta bellii. Mean rates of evaporative water loss varied markedly among the species (0.9–11.4 mg g−1 d−1) and were lowest in the terrestrial hibernators. Most species tolerated the loss of a modest amount of body water, although half of the sample of S. carinatus died from desiccation. In general, turtles did not regain lost body water from wet soil, and immersion in free water was required for rehydration. Therefore, desiccation resistance may be an important adaptation to terrestrial hibernation. Resistances to inoculative freezing and desiccation were directly correlated, perhaps because they are governed by the same morphological characteristics
Post–Breast Cancer Lymphedema and the Family: A Qualitative Investigation of Families Coping With Chronic Illness
Get PDFThe number of women who experience breast cancer is increasing. Meanwhile
there have been improvements in technologies used for detection and
intervention. As a result, more women are living as breast cancer survivors
who are now dealing with issues of quality of life related to the aftereffects of
treatments. For about one third of women who have treatments involving the
removal of and/or irradiation of the axillary lymph nodes, secondary lymphedema
of the arm is likely to develop.We take a qualitative approach to investigating
how lymphedema affects these women and their families in terms of
task completion and family functioning. The Family Adjustment and Adaptation
Response (FAAR) Model is used to interpret findings. These indicate
that families who are more flexible in modifying daily tasks and who have preexisting
resources for coping with stressors have more positive outcomes
than do those families who are rigid and cope with stressors poorly
Final Report on Development and Testing for Resident Satisfaction Survey
No full textThis report provides information about the reliability and validity of the Ohio Nursing Home Resident Satisfaction Survey. The report provides information about short and long-term residents, test-retest and inter-rater reliability, criterion validity information, cognitive screening of nursing home residents, sampling strategies and a plan for data analysis of the Ohio Nursing Home Family Satisfaction Survey
Identification of ice nucleating active Pseudomonas fluorescens strains for biological control of overwintering Colorado potato beetles (Coleoptera: Chrysomelidae).
Get PDFLaboratory studies were conducted to identify ice-nucleating active bacterial strains able to elevate the supercooling point, the temperature at which freezing is initiated in body fluids, of Colorado potato beetles, Leptinotarsa decemlineata (Say), and to persist in their gut. Adult beetles fed ice-nucleating active strains of Pseudomonas fluorescens, P. putida, or P. syringae at 10(6) or 10(3) bacterial cells per beetle had significantly elevated supercooling points, from -4.5 to -5.7 degrees C and from -5.2 to -6.6 degrees C, respectively, immediately after ingestion. In contrast, mean supercooling point of untreated control beetles was -9.2 degrees C. When sampled at 2 and 12 wk after ingestion, only beetles fed P. fluorescens F26-4C and 88-335 still had significantly elevated supercooling points, indicating that these strains of bacteria were retained. Furthermore, beetle supercooling points were comparable to those observed immediately after ingestion, suggesting that beetle gut conditions were favorable not only for colonization but also for expression of ice-nucleating activity by these two strains. The results obtained from exposure to a single, low dose of either bacterial strain also show that a minimum amount of inoculum is sufficient for establishment of the bacterium in the gut. Persistence of these bacteria in Colorado potato beetles long after ingestion was also confirmed using a polymerase chain reaction technique that detected ice-nucleating active bacteria by virtue of their ina genes. Application of these ice-nucleating active bacteria to elevate the supercooling point of this freeze-intolerant insect pest could significantly reduce their winter survival, thereby reducing local populations and, consequently, crop damage
Inoculative freezing and the problem of winter survival for freshwater macroinvertebrates
Get PDFDue to the thermal buffering of their environment, aquatic invertebrates are less likely than their terrestrial counterparts to face temperatures substantially below 0°C. Aquatic invertebrates may not be able to avoid internal freezing by supercooling (remaining unfrozen at temperatures below the freezing point of their body fluids), however, because when their body temperatures reach the freezing point of body fluids, these organisms will likely be in contact with external ice, which may induce formation of internal ice (i.e., inoculative freezing). In this study, a variety of winter-collected, aquatic invertebrates (a clam, Sphaerium sp.; an isopod, Lirceus fontinalis; a mayfly, Stenomena femoratum; a belostomatid, Belostoma flumineum; 2 dytiscids, Ilybius oblitus and Agabus disintegratus) and, for comparison, a terrestrial beetle (Hippodamia convergens) were studied with respect to their low temperature tolerance. No species appeared to lower its freezing point appreciably by accumulating colligatively active solutes in body fluids, and all aquatic species supercooled moderately (-5 to -7°C), but significantly less than the terrestrial beetle (-16°C), before freezing when chilled in a dry environment. However, when chilled in contact with external ice, all animals froze at their melting points or just below (as low as ∼-2°C for the beetles), showing that they are susceptible to inoculative freezing. All aquatic species readily survived exposures to sub-zero temperatures when supercooled, but succumbed to the same conditions when inoculated by external ice. Survival of low temperatures by temperate zone aquatic invertebrates appears to depend upon thermal buffering provided by the aquatic environment, slow progress of ice formation in bodies of water at high sub-zero temperatures, avoidance of contact with external ice, and tolerance of high sub-zero temperatures when freezing does not occur in the animals themselves
Freezing impairment of male reproductive behaviors of the freeze-tolerant wood frog, Rana sylvatica.
Get PDFThe wood frog (Rana sylvatica), a temperate-zone anuran that overwinters within the frost zone, is adapted to tolerate the freezing and thawing of its tissues. Because the effects of freezing on complex neurobehavioral function are unknown and because R. sylvatica encounters subfreezing temperatures during its late-winter breeding season, we investigated the reproductive behaviors and physiology of male frogs after freezing (minimum body temperature, -2°C) and postthaw recovery (4°C). In tests simulating conditions at the breeding pool, these frogs, which otherwise behaved normally, exhibited reduced mate-searching effort and fewer assaults on mates and did not amplex females until 16-24 h after thawing. Although amplectic ability was ultimately restored in most frogs, they competed poorly for mates against never frozen controls. Further study suggested that the level of behavioral impairment depends on the severity of the freezing exposure. During freezing, tissues accumulated large quantities of the cryoprotectant glucose and desiccated extensively, responses that promote freezing survival. Freezing also caused marked hydroosmotic and metabolic perturbations, which may have impaired neurobehavioral function, perhaps by interfering with the processing of audio, visual, and tactile stimuli. Individuals that encounter subfreezing temperatures shortly before arriving at the breeding pools may incur reduced reproductive success