Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager.

Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared observations show a spectrum with strong methane and water-vapor absorption. Modeling of the spectra and photometry yields a luminosity (normalized by the luminosity of the Sun) of 1.6 to 4.0 × 10(-6) and an effective temperature of 600 to 750 kelvin. For this age and luminosity, "hot-start" formation models indicate a mass twice that of Jupiter. This planet also has a sufficiently low luminosity to be consistent with the "cold-start" core-accretion process that may have formed Jupiter.

Increased delay discounting tracks with a high ethanol-seeking phenotype and subsequent ethanol seeking but not consumption.

BACKGROUND: Increased levels of delay discounting have been associated with alcoholism and problematic levels of drinking. Attempts to assess the directionality of this relationship by studying individuals with a family history of alcoholism as well as rodent lines selectively bred for high home cage alcohol preference have yielded discordant results. One possible reason for this discordance is that increased levels of delay discounting may only track with specific processes that lead to addiction vulnerability. This study investigated this possibility by assessing 3 strains of rats previously identified to exhibit heritable differences in ethanol (EtOH) seeking and consumption. METHODS: In an adjusting amount delay discounting task, alcohol-preferring (P) rats who display high levels of both EtOH seeking and consumption were compared to high alcohol-drinking (HAD2) rats who only exhibit moderate EtOH seeking despite high levels of consumption, and Long Evans (LE) rats who display moderate seeking and consumption. EtOH-seeking and consumption phenotypes were subsequently confirmed in an operant self-administration task with a procedural separation between EtOH seeking and drinking. RESULTS: P rats discounted delayed rewards to a greater extent than both HAD2s and LE who did not show differences in discounting. Moreover, the EtOH-seeking and drinking phenotypes were replicated with P rats displaying greater EtOH seeking compared to both the HAD2s and LE, and both the HAD2s and P rats consuming more EtOH than LEs. CONCLUSIONS: Only the high-seeking strain, the P rats, exhibited increased levels of delay discounting. This suggests that this measure of behavioral under-control is specifically associated with alcohol-related appetitive, but not consummatory, processes as the moderate seeking/high drinking line did not show increased levels of impulsivity. This finding supports the hypothesis that delay discounting is specifically associated with only certain processes which are sufficient but not necessary to confer addiction vulnerability and therefore also supports increased levels of delay discounting as a predisposing risk factor for alcoholism.

Erythropoietin and erythropoietin receptor expression in human cancer.

Erythropoietin (EPO) stimulates the growth of erythroblasts in the bone marrow (C. Lacombe and P. Mayeux, NEPHROL: DIAL: TRANSPLANT:, 14 (SUPPL: 2): 22-28, 1999). We report basal and hypoxia-stimulated expression of EPO and its receptor, EPOR, in human breast cancer cells, and we demonstrate EPO-stimulated tyrosine phosphorylation and the proliferation of these cells in vitro. In 50 clinical specimens of breast carcinoma, we report high levels of EPO and EPOR associated with malignant cells and tumor vasculature but not with normal breast, benign papilloma, or fibrocystic tissue. Hypoxic tumor regions display the highest levels of EPO and EPOR expression. Enhanced EPO signaling may contribute to the promotion of human cancer by tissue hypoxia.

The "8-kD" cytoplasmic dynein light chain is required for nuclear migration and for dynein heavy chain localization in Aspergillus nidulans.

The heavy chain of cytoplasmic dynein is required for nuclear migration in Aspergillus nidulans and other fungi. Here we report on a new gene required for nuclear migration, nudG, which encodes a homologue of the "8-kD" cytoplasmic dynein light chain (CDLC). We demonstrate that the temperature sensitive nudG8 mutation inhibits nuclear migration and growth at restrictive temperature. This mutation also inhibits asexual and sexual sporulation, decreases the intracellular concentration of the nudG CDLC protein and causes the cytoplasmic dynein heavy chain to be absent from the mycelial tip, where it is normally located in wild-type mycelia. Coimmunoprecipitation experiments with antibodies against the cytoplasmic dynein heavy chain (CDHC) and the nudG CDLC demonstrated that some fraction of the cytoplasmic dynein light chain is in a protein complex with the CDHC. Sucrose gradient sedimentation analysis, however, showed that not all of the NUDG protein is complexed with the heavy chain. A double mutant carrying a cytoplasmic dynein heavy chain deletion plus a temperature-sensitive nudG mutation grew no more slowly at restrictive temperature than a strain with only the CDHC deletion. This result demonstrates that the effect of the nudG mutation on nuclear migration and growth is mediated through an interaction with the CDHC rather than with some other molecule (e.g., myosin-V) with which the 8-kD CDLC might theoretically interact.

Circumstellar disks and the search for neighbouring planetary systems.

The recent discoveries of planets orbiting several 'mature' stars bring new life to the question of just how common other planetary systems might be. Observations of very young stars provide a way to address this question and suggest that a significant number of such stars harbour conditions appropriate for the formation of planetary systems like our own.

Nuclear migration advances in fungi.

Nuclear migration encompasses three areas: separation of daughter nuclei during mitosis, congress of parental nuclei before they fuse during fertilization, and positioning of nuclei in interphase cells. This review deals primarily with interphase nuclear migration, which is crucial for events as disparate as vertebrate embryonic development and growth of fungal mycelia. Mutants of Aspergillus nidulans, Neurospora crassa and Saccharomyces cerevisiae have been particularly informative, and a detailed molecular analysis of this process is now well under way.

A preliminary study of the impact of terminal illness on spouses: social support and coping strategies.

This study examined whether social support and particular coping strategies were associated with self-reported depression, anxiety, anger, and physical symptoms in spouses of terminally ill patients recently admitted to a hospice program. Forty-four spouses were assessed within two weeks of the patients' admission. Results showed that specific types of social support (namely, socialization, guidance, and cognitive information) and the coping strategy of wishful thinking were associated with self-reported level of anxiety. In addition, cognitive information and the coping strategies of wishful thinking and express emotions were associated with self-reported level of anger. Directionality and possible explanations for these findings are discussed.

The dynein genes of Paramecium tetraurelia. Sequences adjacent to the catalytic P-loop identify cytoplasmic and axonemal heavy chain isoforms.

Paramecium tetraurelia is a unicellular organism that utilizes both axonemal and cytoplasmic dyneins. The highly conserved region containing the catalytic P-loop of the dynein heavy chain was amplified by RNA-directed polymerase chain reaction. Eight different P-loop-containing cDNA fragments were cloned. Southern hybridization analysis indicated that each fragment corresponds to a separate dynein gene and that there are at least 12 dynein heavy chain genes expressed in Paramecium. Seven of the eight cloned contain sequence motif A, which is found in axonemal dyneins, and one contains sequence motif B, which is found in the dyneins from cell types that do not have cilia or flagella. Two of the Paramecium dynein genes were further investigated: DHC-6 which contains motif A, and DHC-8 which contains motif B. Additional sequencing of the central portions of these genes showed that DHC-6 most closely matches sea urchin ciliary beta heavy chain and DHC-8 is similar to the cytoplasmic dynein from Dictyostelium. Deciliation of the cells resulted in a substantial increase in the steady state concentration of DHC-6 mRNA but only a small change in DHC-8 mRNA. Antisera were produced against synthetic peptides derived from sequence motifs A and B. Competitive solid-phase binding assays demonstrated that each antiserum was peptide-specific. In western blots, the antiserum to motif A reacted with both ciliary and cytoplasmic dyneins. In contrast, the antiserum to motif B reacted with the cytoplasmic dyneins of Paramecium and bovine brain but did not react with ciliary dynein.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytoplasmic dynein is involved in nuclear migration in Aspergillus nidulans.

Nuclear migration plays an important role in the growth and development of many organisms including the multinuclear fungus Aspergillus nidulans. We have identified four genes, nudA, nudC, nudF, and nudG, in which temperature-sensitive mutations affect nuclear distribution. In this report, we describe the cloning of the nudA gene by complementation of the mutant phenotype by using a chromosome VIII-specific cosmid library. A genomic fragment of nudA hybridized to an mRNA of approximately 14 kb. Sequencing analysis of nudA revealed four ATP-binding sites that are characteristic of the cytoplasmic dynein heavy chain. The amino acid sequence of the nudA gene product shows 52% overall identity with the rat brain cytoplasmic dynein heavy chain. Our study provides in vivo evidence that dynein, a microtubule motor molecule, plays a role in the nuclear migration process.

Ciliary dynein of Paramecium tetraurelia: photolytic maps of the three heavy chains.

The ciliate Paramecium tetraurelia presents a powerful system to define the structural basis for dynein functional diversity within a single cell. This analysis will depend on the biochemical resolution of the dynein proteins. As an important first step, the three heavy chains of the ciliary outer arm dynein of paramecium were characterized. Sucrose density gradient centrifugation in a high salt buffer separated the dynein into a 22S species, which contained the alpha and beta heavy chains, and a 12S species, which contained the gamma chain as well as the inner arm dynein heavy chains. Both the 22S and 12S species retained enzymatic latency as indicated by stimulation of MgATPase activity by 0.1% Triton X-100. An unusual ATP-independent V1-like photolysis of only the beta chain provided the basis for estimating that the beta chain contributes almost half of the 22S MgATPase activity that is susceptible to V1 photolysis. The combination of the density gradient separation of the partially dissociated dynein and the ATP-independent V1-like photolysis of only the beta chain led to the unambiguous assignment of the V1 photolytic products to the appropriate parent heavy chains. An estimate of the molecular sizes of the three heavy chains was obtained. The photolytic peptide maps, which define the ATP-binding domains, were determined for the three heavy chains.

Identification of spouses at high risk during bereavement: a preliminary assessment of Parkes and Weiss' Risk Index.

The Risk Index developed by Parkes and Weiss (1983) is a brief structured assessment tool for identifying bereaved spouses who may be at high risk for developing complications during bereavement. The present study was undertaken to evaluate the utility of the Risk Index in predicting outcome during the first year of bereavement in spouses of deceased hospice patients. Professional staff at the hospice completed the Risk Index shortly after the spouse died and outcome was then assessed after 1, 3, 6, and 12 months. High-risk bereaved were younger than low-risk bereaved. Number of young children at home, existence of close relationships, and financial status were important predictors of outcome during the first year of bereavement. The findings suggest that the Risk Index may serve as a cost-effective means of assessing risk for complications during the first year of bereavement.

Active stabilization system for Fabry-Perot interferometers.

We describe an optical technique to monitor and stabilize the cavity spacing of a Fabry-Perot interferometer, allowing it to be used as a tunable filter.

The use of time-expanded speech in judgments of hypernasality.

Twenty-five samples of various degrees of hypernasal speech were time altered (expanded) to 0%, 125%, 175% of the original time. Inexperienced and experienced student clinicians rated the magnitude of hypernasality and degree of confidence of ratings for each sample in each condition. The results indicate significant differences in ratings of hypernasality for the expansion conditions for both groups. Experienced clinicians showed less variability and higher mean ratings than inexperienced clinicians.