Plant canopy shape and the influences on UV exposures to the canopy

The solar spectra at selected sites over hemispherical, conical and pinnacle plant canopy models has been evaluated with a dosimetric technique. The irradiance at the sites varies by up to a factor of 0.31 compared to the irradiance on a horizontal plane. The biologically effective (UVBE) exposures evaluated with the dosimetric technique at sites over the plant canopy are up to 19% of that on a horizontal plane. Compared to a spectroradiometer, the technique provides a more practicable method of measuring the UVBE exposures at multiple sites over a plant canopy. Usage of a dosimeter at one site to provide the exposures at that site for different sun angles introduces an error of more than 50%. Knowledge of the spectra allowed the UV and UVBE exposures to be calculated at each site along with the exposures to the entire canopies. These were dependent on the sun angle and the canopy shape. For plant damage, the UVBE was a maximum of about 1.4 mJ cm-2/min. Compared to the hemispherical canopy, the UVBE exposure for generalised plant damage was 45% less for the pinnacle canopy and 23% less for the conical canopy. The canopy exposures could not be determined from measurements of the ambient exposure

High resolution, low temperature photoabsorption cross-section of C2H2 with application to Saturn's atmosphere

New laboratory observations of the VUV absorption cross-section of C2H2, obtained under physical conditions approximating stratospheres of the giant planets, were combined with IUE observations of the albedo of Saturn, for which improved data reduction techniques have been used, to produce new models for that atmosphere. When the effects of C2H2 absorption are accounted for, additional absorption by other molecules is required. The best-fitting model also includes absorption by PH3, H2O, C2H6 and CH4. A small residual disagreement near 1600 A suggests that an additional trace species may be required to complete the model

Gravitational wave bursts from cusps and kinks on cosmic strings

The strong beams of high-frequency gravitational waves (GW) emitted by cusps and kinks of cosmic strings are studied in detail. As a consequence of these beams, the stochastic ensemble of GW's generated by a cosmological network of oscillating loops is strongly non Gaussian, and includes occasional sharp bursts that stand above the ``confusion'' GW noise made of many smaller overlapping bursts. Even if only 10% of all string loops have cusps these bursts might be detectable by the planned GW detectors LIGO/VIRGO and LISA for string tensions as small as $G \mu \sim 10^{-13}$. In the implausible case where the average cusp number per loop oscillation is extremely small, the smaller bursts emitted by the ubiquitous kinks will be detectable by LISA for string tensions as small as $G \mu \sim 10^{-12}$. We show that the strongly non Gaussian nature of the stochastic GW's generated by strings modifies the usual derivation of constraints on $G \mu$ from pulsar timing experiments. In particular the usually considered ``rms GW background'' is, when G \mu \gaq 10^{-7}, an overestimate of the more relevant confusion GW noise because it includes rare, intense bursts. The consideration of the confusion GW noise suggests that a Grand Unified Theory (GUT) value $G \mu \sim 10^{-6}$ is compatible with existing pulsar data, and that a modest improvement in pulsar timing accuracy could detect the confusion noise coming from a network of cuspy string loops down to $G \mu \sim 10^{-11}$. The GW bursts discussed here might be accompanied by Gamma Ray Bursts.Comment: 24 pages, 3 figures, Revtex, submitted to Phys. Rev.

Large Extra Dimensions, Sterile neutrinos and Solar Neutrino Data

Solar, atmospheric and LSND neutrino oscillation results require a light sterile neutrino, $\nu_B$, which can exist in the bulk of extra dimensions. Solar $\nu_e$, confined to the brane, can oscillate in the vacuum to the zero mode of $\nu_B$ and via successive MSW transitions to Kaluza-Klein states of $\nu_B$. This new way to fit solar data is provided by both low and intermediate string scale models. From average rates seen in the three types of solar experiments, the Super-Kamiokande spectrum is predicted with 73% probability, but dips characteristic of the 0.06 mm extra dimension should be seen in the SNO spectrum.Comment: 4 pages, 2 figure

The Five Planets in the Kepler-296 Binary System All Orbit the Primary: A Statistical and Analytical Analysis

Kepler-296 is a binary star system with two M-dwarf components separated by 0.2 arcsec. Five transiting planets have been confirmed to be associated with the Kepler-296 system; given the evidence to date, however, the planets could in principle orbit either star. This ambiguity has made it difficult to constrain both the orbital and physical properties of the planets. Using both statistical and analytical arguments, this paper shows that all five planets are highly likely to orbit the primary star in this system. We performed a Markov-Chain Monte Carlo simulation using a five transiting planet model, leaving the stellar density and dilution with uniform priors. Using importance sampling, we compared the model probabilities under the priors of the planets orbiting either the brighter or the fainter component of the binary. A model where the planets orbit the brighter component, Kepler-296A, is strongly preferred by the data. Combined with our assertion that all five planets orbit the same star, the two outer planets in the system, Kepler-296 Ae and Kepler-296 Af, have radii of 1.53 +/- 0.26 and 1.80 +/- 0.31 R_earth, respectively, and receive incident stellar fluxes of 1.40 +/- 0.23 and 0.62 +/- 0.10 times the incident flux the Earth receives from the Sun. This level of irradiation places both planets within or close to the circumstellar habitable zone of their parent star.Comment: Accepted for publication in Ap

Prognostic significance of the bcl-2 apoptotic family of proteins in primary and recurrent cervical cancer

bcl-2 is one of a family of genes that control the apoptotic threshold of a cell. bcl-2 protein and its anti-apoptotic homologue, mcl-1, with the pro-apoptotic protein, bax, are thought to function by forming homo- and heterotypic dimers that then control the progression to apoptosis. p53 is also involved as a down-regulator of bcl-2 and a promoter of bax. To determine the effect of these apoptotic mechanisms, we used immunohistochemistry to determine the prognostic significance of the expression of bcl-2, mcl-1, bax and p53 in primary and recurrent cervical cancer. Tissues from 46 patients with primary cervical cancer and 28 women with recurrent carcinoma were stained for bcl-2, mcl-1, bax and p53. Kaplan-Meier survival analysis was performed using the log-rank test for differences between groups. In the primary disease group, positive staining for bcl-2 was associated with a better 5-year survival (bcl-2 +ve, 84% vs bcl-2 -ve, 53%, P = 0.03). Positive staining for p53 was associated with a survival disadvantage (p53 +ve, 4-year survival 38% vs p53 -ve, 4-year survival 78%, P = 0.02). mcl-1 and bax staining were not useful as prognostic indicators in primary disease. No marker was prognostic in recurrent disease. Positive bcl-2 staining defines a group of patients with primary disease with a good prognosis. p53, an activator of the bax promoter, identifies a group with a worse outcome. In recurrent disease, none of the markers reflected prognosis

The prognostic significance of beta human chorionic gonadotrophin and its metabolites in women with cervical carcinoma

AIMS: To examine long term survival of women with primary and recurrent cervical carcinoma in relation to (1) excretion of beta-core (a urinary metabolite of beta human chorionic gonadotrophin (beta hCG)) and (2) beta hCG immunostaining of the tumours, to determine the suitability of these markers for assessing prognosis. METHODS: This was a prospective observational study undertaken in a gynaecological oncology centre: 57 women with primary cervical cancer and 42 with recurrent disease were recruited between January 1990 and September 1992. Kaplan-Meier survival analysis with the log rank test was used to assess survival differences with survival rate given per year of follow up. RESULTS: In primary disease, the four year survival for the beta-core negative group was 79%, compared with 14% for the beta-core positive group (p = 0.001). This was still significant for early stage disease or squamous lesions alone. In recurrent disease, beta-core positivity was not prognostically significant. Immunohistochemistry was of no prognostic significance in either group. CONCLUSIONS: beta-core excretion appears to be useful in assessing prognosis of primary cervical cancer but not of recurrent disease. A large prospective study of urinary beta-core in early stage cervical cancer is needed to determine whether it can be used as an index for modifying treatment

The Shape and Scale of Galactic Rotation from Cepheid Kinematics

A catalog of Cepheid variables is used to probe the kinematics of the Galactic disk. Radial velocities are measured for eight distant Cepheids toward l = 300; these new Cepheids provide a particularly good constraint on the distance to the Galactic center, R_0. We model the disk with both an axisymmetric rotation curve and one with a weak elliptical component, and find evidence for an ellipticity of 0.043 +/- 0.016 near the Sun. Using these models, we derive R_0 = 7.66 +/- 0.32 kpc and v_circ = 237 +/- 12 km/s. The distance to the Galactic center agrees well with recent determinations from the distribution of RR Lyrae variables, and disfavors most models with large ellipticities at the solar orbit.Comment: 36 pages, LaTeX, 10 figure

Classifying Data Deposited by Scientists into a Library\u27s Data Repository

In 2014, a team of librarians at Brown University began a concerted effort to ingest, describe, and publish scientific data and digital scholarship into the Brown Library’s data repository, the Brown Digital Repository (BDR). The Library targeted outreach towards student, staff, and faculty researchers in the sciences to encourage them to deposit their digital scholarship, such as digital research products related to grants and data related to their publications, into the BDR. This poster presents a snapshot of the types of scholarship that were deposited by scientists during a 2-year period and classifies the nature of these digital objects. The authors looked at the total number of files deposited by scientists over this period and created a tool to classify and categorize these objects in order to characterize the nature of digital scholarship that scientists were depositing. The instrument classified these objects into several categories and subcategories based on concrete criteria. The first category described digital objects associated with a publication. Data in this category were further classified into the subcategories “underlying data” and “supplementary data”. Underlying data included files that contained the results reported in the publication, files necessary for the peer review of the paper’s reported results and/or necessary for replication or reproduction of research results, such as code that was used to analyze results. The supplementary data were files accompanying a publication, including tables, graphs or visualizations that were not able to be included in the paper or were referenced by authors. The second category was files created by student, staff or faculty researchers not related to a publication but could stand alone as scholarly products equivalent to a publication, such as research posters, animations, visualizations, or software. The last category described digital collections, and included three subcategories: legacy data, digital libraries, and grants. Legacy data were digital products published by retiring faculty or faculty nearing the end of their research careers. Digital libraries included the published collections of scientific data not associated with a single publication. These collections could be published by individual researchers, a collaborative team, labs, and/or departments, and their purpose is to make these items available for other researchers to access and reuse. Lastly, the subcategory grant data contained collections of scientific data and/or other types of digital scholarship associated with a funded-project. These collections could be published by individual researchers, a collaborative team, labs, and/or departments, and the purpose is to disseminate items resulting from sponsored research and/or make these resulting grant-funded digital objects available for other researchers and/or the public