Complete characterization of quantum-optical processes

The technologies of quantum information and quantum control are rapidly improving, but full exploitation of their capabilities requires complete characterization and assessment of processes that occur within quantum devices. We present a method for characterizing, with arbitrarily high accuracy, any quantum optical process. Our protocol recovers complete knowledge of the process by studying, via homodyne tomography, its effect on a set of coherent states, that is, classical fields produced by common laser sources. We demonstrate the capability of our protocol by evaluating and experimentally verifying the effect of a test process on squeezed vacuum.     

Secular trends in the association of socio-economic position with self-reported dietary attributes and biomarkers in the US population: National Health and Nutrition Examination Survey (NHANES) 1971-1975 to NHANES 1999-2002

OBJECTIVE: Recent reports suggest persistence of health disparities related to socio-economic position (SEP). To understand if diet may be a contributor to these trends, we examined secular trends in the association of diet and indicators of SEP from 1971-1975 to 1999-2002. DESIGN: We used data from the National Health and Nutrition Examination Surveys (NHANES) I (1971-1975), II (1976-1980), III (1988-1994) and 1999-2002 to examine the independent associations of poverty income ratio (PIR) and education with diet and biomarkers of diet and disease in 25-74-year-olds (n = 36,600). We used logistic and linear regression methods to adjust for multiple covariates and survey design to examine these associations. RESULTS: A large PIR differential in the likelihood of reporting a fruit or all five food groups and vitamin C intake, and an education differential in likelihood of obesity and carbohydrate intake, was noted in 1971-1975 but narrowed in 1999-2002 (P < 0.007). The positive association of education with intake of a fruit, vegetable or all five food groups, vitamins A and C, calcium and potassium intake remained unchanged across surveys (P < 0.001). Similarly, the positive association of PIR with the amount of foods and intakes of energy and potassium remained unchanged over three decades (P < 0.001). The education and the PIR differential in energy density, and the PIR differential in the likelihood of obesity, persisted over the period of the four surveys (P < 0.001). CONCLUSIONS: Persistence of unfavourable dietary and biomarker profiles in Americans with low income and education suggests continued need for improvement in the quality of diets of these high-risk groups.     

Hepatic fibrosis and mineralization in a free-ranging barren-ground caribou (Rangifer tarandus groenlandicus) from the Northwest Territories

Due to concerns about the appearance of portions of liver from a harvested adult, male barren-ground caribou (Rangifer tarandus groenlandicus), samples were submitted for diagnostic investigation. The gross and histologic findings were consistent with severe hepatic fibrosis and mineralization. Concentrations of vitamin E in the liver were also deficient. Disease investigations in wildlife of detectable abnormalities such as this provide important information for understanding the role of disease as populations change, as well as for safety of human food sources.     

Threat and response: A decade of decline in a regionally endangered rainforest palm affected by fire and introduced animals

The wild population of the palm Ptychosperma macarthurii near Darwin, in monsoonal northern Australia, is regionally endangered and provides a focus to illustrate a range of issues pertinent to conservation of rainforest habitat. Surveys in 1990 found that several populations exhibited a polarised size class structure typified by large adults and small juvenile plants. Over the following decade, in the absence of wildfire and in a period of reduced disturbance from introduced buffalo (Bubalus bubalis), cattle (Bos indicus) and pig (Sus scrofa), sufficient small juvenile plants survived and grew so as to infill the intermediate size classes. Three stage (bifid, juvenile and adult) transition matrix models characterised the population as declining under all observed conditions (intrinsic rate of increase: unburnt + few animals 0.9850; unburnt + many animals 0.9584; burnt <1 year 0.8737; burnt 1-2 years 0.9146; burnt >2 years 0.9937). In the absence of fire, simulations conducted to explore management options revealed a positive rate of increase with exclusion of introduced animals. With only partial introduced animal control or supplementation with juvenile plants, the median rate of increase remained negative. The regional population is at risk by more frequent and more intense fire due to the invasion of exotic grass species and land use changes in the catchment which result in an increased drying of the rainforest habitat. Ongoing decline is the most likely outcome in the absence of effective management intervention.     

A familial degenerative neuromuscular disease of Gelbvieh cattle.

A degenerative skeletal muscle disease with vascular, neurologic, and renal lesions and a probable familial distribution was identified in 4-20-month-old purebred Gelbvieh cattle. Thirteen affected animals were confirmed from 6 separate beef herds, with a mortality rate of 100%. Clinical signs in affected animals consisted of ataxia, weakness, and terminal recumbency. Gross and histologic muscle lesions were indicative of nutritional myopathy of ruminants, with a lack of myocardial lesions in most cases and only rare myocardial changes in a few animals. Acute to chronic lesions in most large skeletal muscle groups consisted of degeneration, necrosis, regeneration, fibrosis, and atrophy. Fibrinoid necrosis of arterioles was a common feature in multiple tissues. Lesions in the spinal cord white matter and peripheral nerves consisted of degeneration of the dorsal columns and axons, respectively. Changes in the kidneys consisted of chronic interstitial nephritis with fibrosis, hyaline droplet change and tubular epithelial vacuolar change and were most severe in the older calves. Intracytoplasmic myoglobin and iron were demonstrated within the hyaline droplets in degenerate renal cortical tubular epithelial cells. Vitamin E levels were deficient in most (6/7) of the animals tested. Investigation of the pedigree of affected animals revealed a common ancestry for all but 1 of the animals whose parentage could be traced. This investigation suggests that a hereditary metabolic defect, possibly involving antioxidant metabolism, could be responsible for this condition. Renal disease, possibly secondary to myoglobinuria, may be unique to this bovine condition.     

Clinical outcome of nonnasal chondrosarcoma in dogs: thirty-one cases (1986-2003)

OBJECTIVE: To evaluate metastatic rate and survival times of dogs with chondrosarcoma of nonnasal bony sites treated by wide surgical excision. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=31) with chondrosarcoma. METHODS: Medical records were retrospectively reviewed to identify dogs with chondrosarcoma of bone in potentially surgically accessible sites. When complete information was not available in the medical record, owners and referring veterinarians were contacted by telephone to evaluate the course of disease and survival times. When possible, histopathologic diagnosis was confirmed by a single board certified pathologist and tumors were histologically graded. RESULTS: Dogs treated by wide surgical excision (n=18) had a mean survival time of 3097 days and did not reach median survival time. Dogs untreated except for diagnostic biopsy (n =13) had a median survival time of 523 days and a mean survival time of 495 days. Method of treatment and tumor grade predicted survival time (P=.016 and P=.007, respectively). Metastatic rate was 28% for treated dogs and 15% for untreated dogs, with no significant difference between the 2 groups (P=.39). CONCLUSIONS: Wide surgical excision significantly improves survival time for dogs with chondrosarcoma of nonnasal bony sites, but does not affect the likelihood of metastasis. Grade may be prognostic for survival. CLINICAL RELEVANCE: Surgical excision benefits dogs with chondrosarcoma and can result in prolonged survival times. Metastasis still occurs in approximately 1 of 4 dogs even after surgical resection.     

Marine extinctions revisited

In recent years, more than 130 extinctions have been estimated to have occurred in the marine realm. Here we review this body of evidence and show that this figure may actually be overestimated by as much as 50%. We argue that previous estimates have not fully taken into account critical uncertainties such as naturally variable geographical distributions, and have misinterpreted documentary evidence. However, current evidence indicates that some sharks, rays and reef‐associated species, although not necessarily geographically restricted, are particularly vulnerable to anthropogenic impacts and now occur in very low numbers. Overestimating extinctions is of concern because it could reduce confidence in the credibility of the ‘extinct’ category in threatened species lists and, ultimately, be used to question the integrity of conservation and management policies. We suggest that when integrating future checklists of marine extinct species, there needs to be a more rigorous use of the terminology of extinction, and participation by specialists in each of the particular taxonomic groups involved.