474 research outputs found
Ocean Chlorophyll Studies from a U-2 Aircraft Platform
Chlorophyll gradient maps of large ocean areas were generated from U-2 ocean color scanner data obtained over test sites in the Pacific and Atlantic Oceans. The delineation of oceanic features using the upward radiant intensity relies on an analysis method which presupposes that radiation backscattered from the atmosphere and ocean surface can be properly modeled using a measurement made at 778 nm. An estimation of the chlorophyll concentration was performed by properly ratioing radiances measured at 472 nm and 548 nm after removing the atmospheric effects. The correlation between the remotely sensed data and in-situ surface chlorophyll measurements was validated in two sets of data. The results show that the correlation between the in-situ measured chlorophyll and the derived quantity is a negative exponential function and the correlation coefficient was calculated to be -0.965
Some Design Considerations for Picture Archiving and Communication Systems
Design considerations for picture archiving and communication systems are reviewed with special emphasis on those issues that differ from conventional network architectures. Design equations for three layers of a picture network are developed and discussed in the context of preliminary estimates of the flow of digital images between a multiplicity of picture sources, picture archives and picture viewing stations. Discussions of differences from conventional networks focuses on the local nature of the net, the availability of a wide-band transmission media with low error rates, the relative costliness of network equipment capable of taking advantage of the wide-band transmission media and the preponderance of large blocks of image data in the network traffic. The locality of network traffic flows associated with the generation, storage and display of images is a characteristic of the radiology application that can probably be used to advantage
Isoform-specific requirement for Akt1 in the developmental regulation of cellular metabolism during lactation
SummaryThe metabolic demands and synthetic capacity of the lactating mammary gland exceed that of any other tissue, thereby providing a useful paradigm for understanding the developmental regulation of cellular metabolism. By evaluating mice bearing targeted deletions in Akt1 or Akt2, we demonstrate that Akt1 is specifically required for lactating mice to synthesize sufficient quantities of milk to support their offspring. Whereas cellular proliferation, differentiation, and apoptosis are unaffected, loss of Akt1 disrupts the coordinate regulation of metabolic pathways that normally occurs at the onset of lactation. This results in a failure to upregulate glucose uptake, Glut1 surface localization, lipid synthesis, and multiple lipogenic enzymes, as well as a failure to downregulate lipid catabolic enzymes. These findings demonstrate that Akt1 is required in an isoform-specific manner for orchestrating many of the developmental changes in cellular metabolism that occur at the onset of lactation and establish a role for Akt1 in glucose metabolism
Elevated Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants.
OBJECTIVE: To determine whether the diastolic closing margin (DCM), defined as diastolic blood pressure minus critical closing pressure, is associated with the development of early severe intraventricular hemorrhage (IVH). STUDY DESIGN: A reanalysis of prospectively collected data was conducted. Premature infants (gestational age 23-31 weeks) receiving mechanical ventilation (n = 185) had ∼1-hour continuous recordings of umbilical arterial blood pressure, middle cerebral artery cerebral blood flow velocity, and PaCO2 during the first week of life. Models using multivariate generalized linear regression and purposeful selection were used to determine associations with severe IVH. RESULTS: Severe IVH (grades 3-4) was observed in 14.6% of the infants. Irrespective of the model used, Apgar score at 5 minutes and DCM were significantly associated with severe IVH. A clinically relevant 5-mm Hg increase in DCM was associated with a 1.83- to 1.89-fold increased odds of developing severe IVH. CONCLUSION: Elevated DCM was associated with severe IVH, consistent with previous animal data showing that IVH is associated with hyperperfusion. Measurement of DCM may be more useful than blood pressure in defining cerebral perfusion in premature infants.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Oxford University Press
Ecological distribution and population physiology defined by proteomics in a natural microbial community
Community proteomics applied to natural microbial biofilms resolves how the physiology of different populations from a model ecosystem change with measured environmental factors in situ.The initial colonists, Leptospirillum Group II bacteria, persist throughout ecological succession and dominate all communities, a pattern that resembles community assembly patterns in some macroecological systems.Interspecies interactions, and not abiotic environmental factors, demonstrate the strongest correlation to physiological changes of Leptospirillum Group II.Environmental niches of subdominant populations seem to be determined by combinations of specific sets of abiotic environmental factors
Supporting genetics in primary care: investigating how theory can inform professional education
Evidence indicates that many barriers exist to the integration of genetic case finding into primary care. We conducted an exploratory study of the determinants of three specific behaviours related to using breast cancer genetics referral guidelines effectively: 'taking a family history', 'making a risk assessment', and 'making a referral decision'. We developed vignettes of primary care consultations with hypothetical patients, representing a wide range of genetic risk for which different referral decisions would be appropriate. We used the Theory of Planned Behavior to develop a survey instrument to capture data on behavioural intention and its predictors (attitude, subjective norm, and perceived behavioural control) for each of the three behaviours and mailed it to a sample of Canadian family physicians. We used correlation and regression analyses to explore the relationships between predictor and dependent variables. The response rate was 96/125 (77%). The predictor variables explained 38-83% of the variance in intention across the three behaviours. Family physicians' intentions were lower for 'making a risk assessment' (perceived as the most difficult) than for the other two behaviours. We illustrate how understanding psychological factors salient to behaviour can be used to tailor professional educational interventions; for example, considering the approach of behavioural rehearsal to improve confidence in skills (perceived behavioural control), or vicarious reinforcement as where participants are sceptical that genetics is consistent with their role (subjective norm)
Jacobsen syndrome
Jacobsen syndrome is a MCA/MR contiguous gene syndrome caused by partial deletion of the long arm of chromosome 11. To date, over 200 cases have been reported. The prevalence has been estimated at 1/100,000 births, with a female/male ratio 2:1. The most common clinical features include pre- and postnatal physical growth retardation, psychomotor retardation, and characteristic facial dysmorphism (skull deformities, hypertelorism, ptosis, coloboma, downslanting palpebral fissures, epicanthal folds, broad nasal bridge, short nose, v-shaped mouth, small ears, low set posteriorly rotated ears). Abnormal platelet function, thrombocytopenia or pancytopenia are usually present at birth. Patients commonly have malformations of the heart, kidney, gastrointestinal tract, genitalia, central nervous system and skeleton. Ocular, hearing, immunological and hormonal problems may be also present. The deletion size ranges from ~7 to 20 Mb, with the proximal breakpoint within or telomeric to subband 11q23.3 and the deletion extending usually to the telomere. The deletion is de novo in 85% of reported cases, and in 15% of cases it results from an unbalanced segregation of a familial balanced translocation or from other chromosome rearrangements. In a minority of cases the breakpoint is at the FRA11B fragile site. Diagnosis is based on clinical findings (intellectual deficit, facial dysmorphic features and thrombocytopenia) and confirmed by cytogenetics analysis. Differential diagnoses include Turner and Noonan syndromes, and acquired thrombocytopenia due to sepsis. Prenatal diagnosis of 11q deletion is possible by amniocentesis or chorionic villus sampling and cytogenetic analysis. Management is multi-disciplinary and requires evaluation by general pediatrician, pediatric cardiologist, neurologist, ophthalmologist. Auditory tests, blood tests, endocrine and immunological assessment and follow-up should be offered to all patients. Cardiac malformations can be very severe and require heart surgery in the neonatal period. Newborns with Jacobsen syndrome may have difficulties in feeding and tube feeding may be necessary. Special attention should be devoted due to hematological problems. About 20% of children die during the first two years of life, most commonly related to complications from congenital heart disease, and less commonly from bleeding. For patients who survive the neonatal period and infancy, the life expectancy remains unknown
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