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At least 37 records · Page 2Linked to original sources
PubMed2001

Relics: penguin population programs.

What has been responsible for the increase in Chinstrap penguin populations during the past 40 years in maritime Antarctica? One view ascribes it to an increase in availability of their prey brought on by the decrease in baleen whale stocks. The contrary opinion, attributes it to environmental warming. This causes a gradual decrease in the frequency of cold years with extensive winter sea ice cover. A number of penguin monitoring programs are in progress and are expected to provide some answers to these questions. Unfortunately, it is not easy to distinguish natural variability from anthropogenic change since penguins are easily accessible predators of krill and the feeding range of the penguins has almost overlapped with the krill fishery in time and space in the last four decades. Therefore it is important to reconstruct the change of ancient penguin abundance and distribution in the absence of human activity. Many efforts have focused on surveying the abandoned penguin rookeries, but this method has not been able to give a continuous historical record of penguin populations. In several recent studies, ancient penguin excreta was scooped from the penguin relics in the sediments of the lake on penguin rookery, Ardley Island, maritime Antarctica. In these studies, penguin droppings or guano soil deposited in the lake and changes in sediment geochemistry have been used to calculate penguin population changes based upon the geochemical composition of the sediment core. The results suggest that climate change has a significant impact on penguin populations.

Animals↗
PubMed1995

Breast-feeding in a low-income population. Program to increase incidence and duration.

OBJECTIVE: To evaluate the efficacy of an intervention program to increase breast-feeding in a low-income, inner-city population. DESIGN: A randomized, nonblinded clinical control trial. Patients were followed up through pregnancy, delivery, and the first year of the infant's life or until the time of weaning from the breast, whichever came first. SETTING: The ambulatory care center for prenatal and pediatric care and the inpatient maternity unit of a primary care center that serves a low-income, inner-city population. PATIENTS: There were a total of 108 patients: 51 were randomized to the intervention group that received prenatal and postnatal lactation instruction from a lactation consultant, and 57 were randomized to the control group that received the standard of care at the institution. Patients in the control group were not seen by the lactation consultant. The two groups were similar demographically. INTERVENTION: This program consisted of individual prenatal lactation consultation, daily rounds by the lactation consultant on the postpartum unit, and outpatient follow-up at 48 hours after discharge, at the time that the infant was 1 week of age, and at all future health supervision visits for infants up to 1 year of age. MAIN OUTCOME MEASURES: The incidence and duration of breast-feeding. RESULTS: There was a markedly higher incidence of breast-feeding in the intervention group, as compared with that of the control group (61% vs 32%, respectively; P = .002). The duration of breast-feeding was also significantly longer in the intervention group (P = .005). CONCLUSIONS: This lactation program increased the incidence and duration of breast-feeding in our low-income cohort. We suggest that similar efforts that are applied to analogous populations may increase the incidence and duration of breast-feeding in low-income populations in the United States.

Adult↗
PubMed2005

Gestational programming: population survival effects of drought and famine during pregnancy.

The process whereby a stimulus or stress at a critical or sensitive period of development has long-term effects is termed "programming." Studies in humans and animals convincingly demonstrate that environmental perturbations in utero may permanently change organ structure and metabolism and/or alter homeostatic regulatory mechanisms among the offspring. These programmed changes may be the origins of adult diseases, including cardiovascular disease, obesity, and diabetes. Throughout evolution and development, humans and animals have been exposed to two common environmental stresses, drought and famine. Notably, drought-induced water deprivation is associated with dehydration anorexia and thus a concomitant potential nutrient stress. Our laboratory has performed studies among pregnant rat and sheep in which we simulate drought conditions via maternal dehydration and famine conditions via nutrient restriction. Maternal dehydration results in low-birth-weight offspring, which demonstrate gender-specific plasma hypernatremia and hypertonicity and arterial hypertension. Gestational nutrient restriction also resulted in low-birth-weight offspring. If permitted rapid catch-up growth by nutrient availability, these offspring demonstrate evidence of increased body weight and body fat, and leptin resistance as adults. Conversely, if the catch-up growth is delayed by nutrition restriction, the offspring exhibit normal body weight, body fat, and plasma leptin levels as adults. These studies indicate that osmoregulatory and cardiovascular homeostasis and phenotypic predisposition to obesity may be programmed in utero. Importantly, these results suggest that programming effects may be either potentiated or prevented by interventions during the neonatal period.

Animals↗
PubMed2005

Long-term monitoring of bacteria undergoing programmed population control in a microchemostat.

Using an active approach to preventing biofilm formation, we implemented a microfluidic bioreactor that enables long-term culture and monitoring of extremely small populations of bacteria with single-cell resolution. We used this device to observe the dynamics of Escherichia coli carrying a synthetic "population control" circuit that regulates cell density through a feedback mechanism based on quorum sensing. The microfluidic bioreactor enabled long-term monitoring of unnatural behavior programmed by the synthetic circuit, which included sustained oscillations in cell density and associated morphological changes, over hundreds of hours.

4-Butyrolactone↗