Assessing the Relative Importance of Satellite-Detected Methane Superemitters in Quantifying Total Emissions for Oil and Gas Production Areas in Algeria.

Methane emissions from oil and gas production provide an important contribution to global warming. We investigate 2020 emissions from the largest gas field in Algeria, Hassi R'Mel, and the oil-production-dominated area Hassi Messaoud. We use methane data from the high-resolution (20 m) Sentinel-2 instruments to identify and estimate emission time series for 11 superemitters (including 10 unlit flares).

Germinal centers and the B cell system. VIII. Functional characteristics and cell surface markers of germinal center cell subsets differing in density and in sedimentation velocity.

Germinal center cells from the rabbit appendix were fractionated by velocity sedimentation and isopycnic gradient centrifugation. Subsets were analysed with respect to cell size and surface markers, and were functionally characterized by testing the capacities for primary antibody synthesis, memory cell production, and formation of new germinal centers in an autologous transfer system. The migratory behaviour of the germinal center cell subsets within the spleen of homologous recipients was also studied using autoradiography.

Germinal centers and the B-cell system. VI. Migration pattern of germinal-center cells of the rabbit appendix.

The migration pattern of germinal center cells of the rabbit appendix was studied and compared with that of appendix dome cells, spleen cells, thymus cells and thoracic duct lymphocytes. To discriminate T- and B-cell migration pathways, normal or T-cell-depleted rabbits were used as donors. Cell suspensions were labeled in vitro with 3H-leucine followed by intravenous transfer.

Germinal centres and the B cell system. IV. Functional characteristics of rabbit appendix germinal centre (-derived) cells.

Functional capacities of rabbit appendix germinal centre cells were tested in appendectomized, 450 rads X-irradiated rabbits, reconstituted with autologous appendix germinal centre cells, which are obtained by mechanical separation--"stripping"--of the appendix. For comparison, functional capacities of appendix germinal centre derived cells were tested in rabbits, 450 rads X-irradiated with the appendix shielded. In both types of experimental systems, slow restoration of primary IgM responsiveness to Salmonella Java paratyphi-B (PAR) was observed; in contrast, the capacity for memory cell production (of both mu and gamma-type) to PAR was restored very early in both systems.

Germinal centres and the B cell system. III. Germinal centre forming capacity of rabbit appendix germinal centre (-derived) cells.

Following appendectomy and sublethal (450 rads) whole body X-irradiation, reconstitution with autologous appendix germinal centre cells led to excellent germinal centre formation in the recipient's spleen. Heat killing of the cells to be injected completely abolished this phenomenon. Apparently a suspension of appendix germinal centre cells contains a (sub)populations of cells capable of germinal centre formation (Germinal Centre Precursor Cells).