The Q-Sort Method: Assessing Reliability And Construct Validity Of Questionnaire Items At A Pre-Testing Stage

This paper describes the Q-sort, which is a method of assessing reliability and construct validity of questionnaire items at a pre-testing stage. The method uses Cohen\u27s Kappa and Moore and Benbasat\u27s Hit Ratio in assessing the questionnaire

New species of the parasites of the Rhodes - grass scale from the Indian union

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Tests of Statistical Methods for Estimating Galaxy Luminosity Function and Applications to the Hubble Deep Field

We studied the statistical methods for the estimation of the luminosity function (LF) of galaxies. We focused on four nonparametric estimators: $1/V_{\rm max}$ estimator, maximum-likelihood estimator of Efstathiou et al. (1988), Cho{\l}oniewski's estimator, and improved Lynden-Bell's estimator. The performance of the $1/V_{\rm max}$ estimator has been recently questioned, especially for the faint-end estimation of the LF. We improved these estimators for the studies of the distant Universe, and examined their performances for various classes of functional forms by Monte Carlo simulations. We also applied these estimation methods to the mock 2dF redshift survey catalog prepared by Cole et al. (1998). We found that $1/V_{\rm max}$ estimator yields a completely unbiased result if there is no inhomogeneity, but is not robust against clusters or voids. This is consistent with the well-known results, and we did not confirm the bias trend of $1/V_{\rm max}$ estimator claimed by Willmer (1997) in the case of homogeneous sample. We also found that the other three maximum-likelihood type estimators are quite robust and give consistent results with each other. In practice we recommend Cho{\l}oniewski's estimator for two reasons: 1. it simultaneously provides the shape and normalization of the LF; 2. it is the fastest among these four estimators, because of the algorithmic simplicity. Then, we analyzed the photometric redshift data of the Hubble Deep Field prepared by Fern\'{a}ndez-Soto et al. (1999) using the above four methods. We also derived luminosity density $\rho_{\rm L}$ at $B$- and $I$-band. Our $B$-band estimation is roughly consistent with that of Sawicki, Lin, & Yee (1997), but a few times lower at $2.0 < z < 3.0$. The evolution of $\rho_{\rm L}(I)$ is found to be less prominent.Comment: To appear in ApJS July 2000 issue. 36 page

Hymenia recurvalis F. and its parasite complex

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The Luminosity Function of Galaxies in SDSS Commissioning Data

During commissioning observations, the Sloan Digital Sky Survey (SDSS) has produced one of the largest existing galaxy redshift samples selected from CCD images. Using 11,275 galaxies complete to r^* = 17.6 over 140 square degrees, we compute the luminosity function of galaxies in the r^* band over a range -23 < M < -16 (for h=1). The result is well-described by a Schechter function with parameters phi_* = 0.0146 +/- 0.0012 h^3 Mpc^{-3}, M_* = -20.83 +/- 0.03, and alpha = -1.20 +/- 0.03. The implied luminosity density in r^* is j = (2.6 +/- 0.3) x 10^8 h L_sun Mpc^{-3}. The surface brightness selection threshold has a negligible impact for M < -18. We measure the luminosity function in the u^*, g^*, i^*, and z^* bands as well; the slope at low luminosities ranges from alpha=-1.35 to alpha=-1.2. We measure the bivariate distribution of r^* luminosity with half-light surface brightness, intrinsic color, and morphology. High surface brightness, red, highly concentrated galaxies are on average more luminous than low surface brightness, blue, less concentrated galaxies. If we synthesize results for R-band or b_j-band using the Petrosian magnitudes with which the SDSS measures galaxy fluxes, we obtain luminosity densities 2.0 times that found by the Las Campanas Redshift Survey in R and 1.4 times that found by the Two-degree Field Galaxy Redshift Survey in b_j. We are able to reproduce the luminosity functions obtained by these surveys if we also mimic their isophotal limits for defining galaxy magnitudes, which are shallower and more redshift dependent than the Petrosian magnitudes used by the SDSS. (Abridged)Comment: 49 pages, including 23 figures, accepted by AJ; some minor textual changes, plus an important change in comparison to LCR

Draft proposal for establishment of CNC centre at NAL

This is a proposal for setting up Computer Numerically Controlled machining facilities at N.A.L. to cater to the increasing requirements for fabrication of complex shaped and intricate/precision components for the aerospace R & D projects of the laboratory for the next 10 - year period. This fairly comprehensive document has been prepared by an internal technical committee constituted by the Director, after detailed study and discussions and covers the technical and financial aspects for setting up such facilities

Host selection and oviposition response in Apanteles angaleti Muesebeck (braconidae: hymenoptera)

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Studies on the biology of the parasites of the pea leaf miner Phytomyza Atricornis (Meigan)

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A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants