Mathematical concept formation for the primary school-aged learning disabled student

This paper is concerned with mathematics and the Learning Disabled student. In this chapter, the rationale, the scope, and the limitations of the study were stated, as well as the definitions of terms to be employed in the research review. The population to be discussed is the primary school-aged Learning Disabled student. The concepts to be examined are: more, less, equal to, more than, greater than, less than, number, set, and the appropriate language for each concept

Vol. 11, No. 2

Contents: Hicks and Hazen Paper: Blessings for Employers or Blessings in Disguise for Employment Discrimination Plaintiffs?, by Richard J. Gonzalez Recent Developments, by the Student Editorial Board Announcements Further References, compiled by Margaret A. Chaplanhttps://scholarship.kentlaw.iit.edu/iperr/1020/thumbnail.jp

Vol. 11, No. 2

Contents: Hicks and Hazen Paper: Blessings for Employers or Blessings in Disguise for Employment Discrimination Plaintiffs?, by Richard J. Gonzalez Recent Developments, by the Student Editorial Board Announcements Further References, compiled by Margaret A. Chaplanhttps://scholarship.kentlaw.iit.edu/iperr/1020/thumbnail.jp

Intraspecific variability drives diversity in food webs

Biodiversity theories neglect individual-level variability in ecological interactions even though empirical work has revealed considerable genetic and phenotypic variation among individuals in natural populations. This impedes assessing the impact of individual-level variability on biodiversity in multi-trophic ecosystems. Here we use a density-dependent and individual-based food web model, tested against the largest individual-based food web to date, to show that non-random intraspecific variation in prey selection alters species diversity in food webs. Predators consuming many prey increase diversity by preferentially selecting common prey; predators consuming few prey inhibit diversity by preferentially selecting rare prey, putting them at risk of extinction. Thus species-level patterns cannot be explained by species-level averages, but instead must consider individual-level variation in prey selection. Individual-level variation occurs in many biological and social contexts, suggesting that analyses of individual-level interaction data will be relevant in a wide range of fields

Models of Metal Poor Stars with Gravitational Settling and Radiative Accelerations: I. Evolution and Abundance Anomalies

Evolutionary models have been calculated for Pop II stars of 0.5 to 1.0$M_\odot$ from the pre-main-sequence to the lower part of the giant branch. Rosseland opacities and radiative accelerations were calculated taking into account the concentration variations of 28 chemical species, including all species contributing to Rosseland opacities in the OPAL tables. The effects of radiative accelerations, thermal diffusion and gravitational settling are included. While models were calculated both for Z=0.00017 and 0.0017, we concentrate on models with Z=0.00017 in this paper. These are the first Pop II models calculated taking radiative acceleration into account. It is shown that, at least in a 0.8$M_\odot$ star, it is a better approximation not to let Fe diffuse than to calculate its gravitational settling without including the effects of $g_{rad}(Fe)$. In the absence of any turbulence outside of convection zones, the effects of atomic diffusion are large mainly for stars more massive than 0.7$M_\odot$. Overabundances are expected in some stars with \teff \ge 6000K. Most chemical species heavier than CNO are affected. At 12 Gyr, overabundance factors may reach 10 in some cases (e.g. for Al or Ni) while others are limited to 3 (e.g. for Fe). The calculated surface abundances are compared to recent observations of abundances in globular clusters as well as to observations of Li in halo stars. It is shown that, as in the case of Pop I stars, additional turbulence appears to be present.Comment: 40 pages, 17 color figures, to appear in The Astrophysical Journal, April 2002 (paper with original high resolution figures can be found at http://www.cerca.umontreal.ca/~richer/Fichiersps/popII_1.ps

Developing of new technologies driving advances in precision agriculture to optimise inputs and reduce environmental footprint

Avances en el sector de la agrotecnología ofrecen la oportunidad de que los sistemas agroalimentarios contribuyan a conseguir objetivos políticos mundiales como lograr sistemas de carbono neto cero y reducir la huella ambiental mediante la eliminación de emisiones nocivas y el aumento de la biodiversidad. Una serie de sensores puede detectar la salud y el estrés de los cultivos debido a amenazas bióticas y abióticas. La detección precoz permite tomar medidas adecuadas antes de que el rendimiento de los cultivos se vea afectado o la presión de plagas y enfermedades no pueda controlarse sin el uso de pesticidas sintéticos. La tecnología de detección utiliza técnicas de imagen o detección de compuestos volátiles mediante e-nose y diagnóstico molecular en tiempo real, identificando patógenos vegetales recogidos en muestras de aire. Los datos generados por estas tecnologías proporcionan a los agricultores información temporal y espacial. Permite identificar plantas individualmente, incluso desde satélite, lo que posibilita aplicar con precisión fertilizantes y pesticidas, directamente a la planta o a la zona de cultivo afectada con técnicas de pulverización controladas a partir utilizando los datos adquiridos.Technological advances in the agri-tech sector offer the opportunity for food production systems to contribute to achieving global policy aims such as achieving net zero carbon systems and reducing environmental footprint through eliminating harmful emissions and increasing biodiversity. Arange of sensors can detect crop health and stress due to biotic and abiotic threats, often with an early detection which permits appropriate action to be taken before crop yield is affected or pest and disease pressure cannot be controlled without the use of synthetic pesticides. Detection technology uses imaging techniques, often beyond the visible spectrum, detection of volatile compounds using e-nose techniques and real time molecular diagnostic techniques to identify plant pathogens collected in air samples. The data generated by such technologies relies on connectivity of the hardware and subsequent analytical processes to provide growers with temporal and spatial information. It is possible to identify plant locations with great accuracy, even with satellite systems, which permits precision application of crop inputs, such as fertilisers and pesticides, directly to the plant or crop area as required. Spray application techniques can now treat individual plants, both crop and weeds, using data acquired to control the flow to individual nozzles

Star formation in the massive cluster merger Abell 2744

We present a comprehensive study of star-forming (SF) galaxies in the HST Frontier Field recent cluster merger A2744 (z=0.308). Wide-field, ultraviolet-infrared (UV-IR) imaging enables a direct constraint of the total star formation rate (SFR) for 53 cluster galaxies, with SFR{UV+IR}=343+/-10 Msun/yr. Within the central 4 arcmin (1.1 Mpc) radius, the integrated SFR is complete, yielding a total SFR{UV+IR}=201+/-9 Msun/yr. Focussing on obscured star formation, this core region exhibits a total SFR{IR}=138+/-8 Msun/yr, a mass-normalised SFR{IR} of Sigma{SFR}=11.2+/-0.7 Msun/yr per 10^14 Msun and a fraction of IR-detected SF galaxies f{SF}=0.080(+0.010,-0.037). Overall, the cluster population at z~0.3 exhibits significant intrinsic scatter in IR properties (total SFR{IR}, Tdust distribution) apparently unrelated to the dynamical state: A2744 is noticeably different to the merging Bullet cluster, but similar to several relaxed clusters. However, in A2744 we identify a trail of SF sources including jellyfish galaxies with substantial unobscured SF due to extreme stripping (SFR{UV}/SFR{IR} up to 3.3). The orientation of the trail, and of material stripped from constituent galaxies, indicates that the passing shock front of the cluster merger was the trigger. Constraints on star formation from both IR and UV are crucial for understanding galaxy evolution within the densest environments.Comment: Accepted by MNRAS. 12 pages, 7 figures (high resolution versions of Figs. 1 & 2 are available in the published PDF

Testing Hall-Post Inequalities With Exactly Solvable N-Body Problems

The Hall--Post inequalities provide lower bounds on $N$-body energies in terms of $N'$-body energies with $N'<N$. They are rewritten and generalized to be tested with exactly-solvable models of Calogero-Sutherland type in one and higher dimensions. The bound for $N$ spinless fermions in one dimension is better saturated at large coupling than for noninteracting fermions in an oscillatorComment: 7 pages, Latex2e, 2 .eps figure

Spitzer and Hubble Constraints on the Physical Properties of the z~7 Galaxy Strongly Lensed by Abell 2218

We report the detection of a z~7 galaxy strongly lensed by the massive galaxy cluster Abell 2218 (z=0.175) at 3.6 and 4.5 um using the Spitzer Observatory and at 1.1 um using the Hubble Space Telescope. The new data indicate a refined photometric redshift in the range of 6.6-6.8 depending on the presence of Ly-alpha emission. The spectral energy distribution is consistent with having a significant Balmer break, suggesting that the galaxy is in the poststarburst stage with an age of at least ~50 Myr and quite possibly a few hundred Myr. This suggests the possibility that a mature stellar population is already in place at such a high redshift. Compared with typical Lyman break galaxies at z~3-4, the stellar mass is an order of magnitude smaller (~10^{9} Msun), but the specific star formation rate (star formation rate/M_{star}) is similarly large (> 10^{-9} yr^{-1}), indicating equally vigorous star-forming activity.Comment: 11 pages, 2 figures, 2 tables; Accepted for publication in ApJ