Central Exclusive Di-jet Production at the Tevatron

We perform a phenomenological analysis of dijet production in double pomeron exchange at the Tevatron. We find that the CDF Run I results do not rule out the presence of an exclusive dijet component, as predicted by Khoze, Martin and Ryskin (KMR). With the high statistics CDF Run II data, we predict that an exclusive component at the level predicted by KMR may be visible, although the observation will depend on accurate modelling of the inclusive double pomeron exchange process. We also compare to the predictions of the DPEMC Monte Carlo, which contains a non-perturbative model for the central exclusive process. We show that the perturbative model of KMR gives different predictions for the di-jet ET dependence in the high di-jet mass fraction region than non-perturbative models.Comment: 17 pages, 15 figure

Erythroid anion transporter assembly is mediated by a developmentally regulated recruitment onto a preassembled membrane cytoskeleton

Analysis of the expression and assembly of the anion transporter by metabolic pulse-chase and steady-state protein and RNA measurements reveals that the extent of association of band 3 with the membrane cytoskeleton varies during chicken embryonic development. Pulse-chase studies have indicated that band 3 polypeptides do not associate with the membrane cytoskeleton until they have been transported to the plasma membrane. At this time, band 3 polypeptides are slowly recruited, over a period of hours, onto a preassembled membrane cytoskeletal network and the extent of this cytoskeletal assembly is developmentally regulated. Only 3% of the band 3 polypeptides are cytoskeletal-associated in 4-d erythroid cells vs. 93% in 10-d erythroid cells and 36% in 15-d erythroid cells. This observed variation appears to be regulated primarily at the level of recruitment onto the membrane cytoskeleton rather than by different transport kinetics to the membrane or differential turnover of the soluble and insoluble polypeptides and is not dependent upon the lineage or stage of differentiation of the erythroid cells. Steady-state protein and RNA analyses indicate that the low levels of cytoskeletal band 3 very early in development most likely result from limiting amounts of ankyrin and protein 4.1, the membrane cytoskeletal binding sites for band 3. As embryonic development proceeds, ankyrin and protein 4.1 levels increase with a concurrent rise in the level of cytoskeletal band 3 until, on day 10 of development, virtually all of the band 3 polypeptides are cytoskeletal bound. After day 10, the levels of total and cytoskeletal band 3 decline, whereas ankyrin and protein 4.1 continue to accumulate until day 18, indicating that the cytoskeletal association of band 3 is not regulated solely by the availability of membrane cytoskeletal binding sites at later stages of development. Thus, multiple mechanisms appear to regulate the recruitment of band 3 onto the erythroid membrane cytoskeleton during chicken embryonic development

Anion transporter: highly cell-type-specific expression of distinct polypeptides and transcripts in erythroid and nonerythroid cells

Affinity-purified antibodies and cDNA probes specific for the chicken erythrocyte anion transporter (also referred to as band 3) have been used to demonstrate that this protein is expressed in a highly cell- type-specific manner in the avian kidney. Indirect immunofluorescence analysis indicates that this polypeptide is present in only a small subset of total kidney cells and is predominantly localized to the proximal convoluted tubule of this organ. Chicken erythrocytes synthesize and accumulate two structurally and serologically related band 3 polypeptides. The polypeptide that accumulates in kidney membranes has an apparent molecular weight greater than either of its erythroid counterparts. This diversity is also reflected at the RNA level, as the single band 3 mRNA species detected during various stages of erythroid development is distinct in size from that found in kidney cells. Genomic DNA blot analysis suggests that both the erythroid and kidney band 3 RNAs arise from a single gene. Furthermore, of the adult tissues we have examined that are known to express ankyrin and spectrin polypeptides, only kidney accumulates detectable levels of the band 3 mRNA and polypeptide. These observations suggest that a subset of kidney cells use an anion transport mechanism analogous to that of erythrocytes and that band 3 is expressed in a noncoordinate manner with other components of the erythroid membrane skeleton in nonerythroid cells

Saturn S-IB stage Final static test report, stage S-IB-2

Acceptance test firing of Saturn flight stage S-IB-

International food patterns for space food

The purpose of this research was to obtain basic data on ethnic foods by studying dietary patterns and multicultural foods, and to determine nutritional status of multicultural space explorers by evaluating dietary, clinical, biochemical, and socioeconomic factors. The study will plan a significant role in providing nutritional research for space explorers of different ethnic backgrounds. It will provide scientific background information by bringing together cross cultural dietary and nutritional from different ethnic groups. Results will also help the health care personnel including physicians, dietitians, and nutritionists to better understand and assist patients from other cultures illness. Also, the results will provide data which will help in the development of future food plans for long duration flights involving manned exploration to Mars and lunar base colonies

Parthenolide eliminates leukemia-initiating cell populations and improves survival in xenografts of childhood acute lymphoblastic leukemia

Key Points First report demonstrating in vivo elimination of multiple LIC populations from childhood ALL cases using animal models. In vivo models of leukemia are essential for drug evaluation studies.</jats:p

The peculiar molecular envelope around the post-AGB star IRAS 08544--4431

Circumbinary disks have been hypothesized to exist around a number of binary post-AGB stars. Although most of the circumbinary disks have been inferred through the near IR excess, a few of them are strong emitters of molecular emission. Here we present high angular resolution observations of the emission of $^{12}$CO and its isotopomer $^{13}$CO J=2--1 line from the circumstellar envelope around the binary post-AGB star IRAS 08544$-$4431, which is one of the most prominent members of this class of objects. We find that the envelope is resolved in our observations and two separate components can be identified: (a) a central extended and strong component with very narrow linewidth between 2 - 6 \kms; (b) a weak bipolar outflow with expansion velocity up to 8 \kms. The central compact component possesses low and variable $^{12}$CO/$^{13}$CO J=2--1 line ratio, indicating optically thick emission of the main isotope. We estimate a molecular gas mass of 0.0047 M$_\odot$ for this component based on the optically thinner $^{13}$CO J=2--1 line. We discuss the relation of the molecular envelope and the circumbinary disk inferred from near IR excess and compare with other known cases where the distribution of molecular gas has been imaged at high angular resolution.Comment: 14 pages, 4 figures. Accepted for publication in Astrophysical Journa