Projective filtering of a single spatial radiation eigenmode

Lossless filtering of a single coherent (Schmidt) mode from spatially multimode radiation is a problem crucial for optics in general and for quantum optics in particular. It becomes especially important in the case of nonclassical light that is fragile to optical losses. An example is bright squeezed vacuum generated via high-gain parametric down conversion or four-wave mixing. Its highly multiphoton and multimode structure offers a huge increase in the information capacity provided that each mode can be addressed separately. However, the nonclassical signature of bright squeezed vacuum, photon-number correlations, are highly susceptible to losses. Here we demonstrate lossless filtering of a single spatial Schmidt mode by projecting the spatial spectrum of bright squeezed vacuum on the eigenmode of a single-mode fiber. Moreover, we show that the first Schmidt mode can be captured by simply maximizing the fiber-coupled intensity. Importantly, the projection operation does not affect the targeted mode and leaves it usable for further applications.Comment: 10 pages, 9 figure

Expanding tropical forest monitoring into dry forests: the DRYFLOR protocol for permanent plots.

Understanding of tropical forests has been revolutionized by monitoring in permanent plots. Data from global plot networks have transformed our knowledge of forests? diversity, function, contribution to global biogeochemical cycles, and sensitivity to climate change. Monitoring has thus far been concentrated in rain forests. Despite increasing appreciation of their threatened status, biodiversity, and importance to the global carbon cycle, monitoring in tropical dry forests is still in its infancy. We provide a protocol for permanent monitoring plots in tropical dry forests. Expanding monitoring into dry biomes is critical for overcoming the linked challenges of climate change, land use change, and the biodiversity crisis

Diagnostic and prognostic value of serum copper and plasma fibrinogen in hepatic carcinoma

To investigate the diagnostic and prognostic value of several biochemical tests in primary liver tumors, the authors studied 36 cases (4 cholangiocarcinomas and 32 hepatocellular carcinomas, 10 of which were associated with cirrhosis) and 47 cases of liver cirrhosis, all with morphologically proven diagnosis. Serum copper (SCu) and plasma fibrinogen (PF) appeared the most useful tests in differential diagnosis between tumors and cirrhosis. In liver tumors, mean SCu level was 200.50, standard deviation (SD) 47.17 micrograms/dl (121.40, SD 25.90 micrograms/dl in cirrhosis; P less than 0.001). PF level was 461.78, SD 151.25 mg/dl in tumors (275.30 SD, 124.40 mg/dl in cirrhosis; P less than 0.001). SCu had a good sensitivity (0.80) and a high specificity (0.92) at a cutoff value of 160 micrograms/dl; when the cutoff level was raised to 170 micrograms/dl, the specificity increased to 1, with a sensitivity of 0.77. The combination of SCu and PF improved the diagnostic value slightly. Moreover, with an estimated frequency of tumor in cirrhosis of 10%, SCu had a positive predictive value of 1 (cutoff, 170 micrograms/dl) and a negative predictive value of 0.97. In nine patients SCu levels decreased after surgical removal of tumor; five other patients, sequentially studied, showed an increase of SCu level that correlated with the progression of the disease. Finally, patients with longer survival had a lower SCu level. These findings suggest that SCu level may be used as a screening test for early detection of neoplastic degeneration, and it is correlated with the extension of tumor mass

Glutathione-peroxidase and glutathione-reductase activities of normal and pathologic human liver: relationship with age

Liver glutathione-peroxidase (L-GSH-Px) and glutathione-reductase (GSSG-Red) activities were measured in supernatants of liver tissues obtained from a total of 36 subjects. Sixteen of these patients had a functionally normal liver (control group), whereas of the remaining 20 patients, 10 were cirrhotic and 10 had a liver disease other than cirrhosis. The mean value of L-GSH-Px of the control group was 33.12 +/- 12.66 U/g protein, a value similar to that found in patients with liver disease. The L-GSH-Px of the control group was positively correlated with the age of the subjects (r = 0.620; p less than 0.02). In contrast, in patients with liver disease an opposite behaviour of the two parameters was noted (r = -0.497; p less than 0.05). L-GSH-Px activity tended to be higher in males than in females, whereas the erythrocyte glutathione-peroxidase (E-GSH-Px) of the same patients was higher in females, albeit not significantly. L-GSH-Px and E-GSH-Px were not correlated either in normal or in liver disease. The mean GSSG-Red of the control group was 40.63 +/- 11.10 U/g protein, which is not different from that of the group of liver patients. GSSG-Red was not correlated with L-GSH-Px or with the age of patients. In two patients with hepatoma, the GSH-Px activity of the cancer tissue was low and the GSSG-Red activity high