Is Justification Necessary for Knowledge?

Justification has long been considered a necessary condition for knowledge, and theories that deny the necessity of justification have been dismissed as nonstarters. In this chapter, we challenge this long-standing view by showing that many of the arguments offered in support of it fall short and by providing empirical evidence that individuals are often willing to attribute knowledge when epistemic justification is lacking

Leptophis modestus

Number of Pages: 2Integrative BiologyGeological Science

Nototriton limnospectator

Number of Pages: 2Integrative BiologyGeological Science

Recent Changes in State and Local Funding for Education in Georgia - Brief

This report examines how the 2001 recession affected K-12 education spending in Georgia school systems. FRC Brief 20

Recent Changes in State and Local Funding for Education in Georgia

This report examines how the 2001 recession affected K-12 education spending in Georgia school systems. FRC Report 20

Invariance of density correlations with charge density in polyelectrolyte solutions

We present a theory for the equilibrium structure of polyelectrolyte solutions. The main element is a simple, new optimization scheme that allows theories such as the random phase approximation (RPA) to handle the harsh repulsive forces present in such systems. Comparison is made with data from recent neutron scattering experiments of randomly charged, hydrophilic polymers in salt-free, semi-dilute solution at various charge densities. Models with varying degrees of realism are examined. The usual explanation of the invariance observed at high charge density has been counterion condensation. However, when polymer-polymer correlations are treated properly, we find that modeling polymer-counterion correlations at the level of Debye-Huckel theory is sufficient.Comment: 4 pages, 2 figure

The herpetofauna of the cloud forests of Honduras

The cloud forest amphibians and reptiles constitute the most important herpetofaunal segment in Honduras, due to the prevalence of endemic and Nuclear Middle American-restricted species. This segment, however, is subject to severe environmental threats due to the actions of humans. Of the 334 species of amphibians and reptiles currently known from Honduras, 122 are known to be distributed in cloud forest habitats. Cloud forest habitats are found throughout the mountainous interior of Honduras. They are subject to a Highland Wet climate, which features annual precipitation of >1500 mm and a mean annual temperature of <18°C. Cloud forest vegetation falls into two Holdridge formations, the Lower Montane Wet Forest and Lower Montane Moist Forest. The Lower Montane Wet Forest formation generally occurs at elevations in excess of 1500 m, although it may occur as low as 1300+ m at some localities. The Lower Montane Moist Forest formation generally occurs at 1700+ m elevation. Of the 122 cloud forest species, 18 are salamanders, 38 are anurans, 27 are lizards, and 39 are snakes. Ninety-eight of these 122 species are distributed in the Lower Montane Wet Forest formation and 45 in the Lower Montane Moist Forest formation. Twenty species are distributed in both formations. The cloud forest species are distributed among restricted, widespread, and peripheral distributional categories. The restricted species range as a group in elevation from 1340 to 2700 m, the species that are widespread in at least one of the two cloud forest formations range as a group from sea level to 2744 m, and the peripheral species range as a group from sea level to 1980 m. The 122 cloud forest species exemplify ten broad distributional patterns ranging from species whose northern and southern range termini are in the United States (or Canada) and South America, respectively, to those species that are endemic to Honduras. The largest segment of the herpetofauna falls into the endemic category, with the next largest segment being restricted in distribution to Nuclear Middle America, but not endemic to Honduras. Cloud forest species are distributed among eight ecophysiographic areas, with the largest number being found in the Northwestern Highlands, followed by the North-Central Highlands and the Southwestern Highlands. The greatest significance of the Honduran herpetofauna lies in its 125 species that are either Honduran endemics or otherwise Nuclear Middle American-restricted species, of which 83 are distributed in the country’s cloud forests. This segment of the herpetofauna is seriously endangered as a consequence of exponentially increasing habitat destruction resulting from deforestation, even given the existence of several biotic reserves established in cloud forest. Other, less clearly evident environmental factors also appear to be implicated. As a consequence, slightly over half of these 83 species (50.6%) have populations that are in decline or that have disappeared from Honduran cloud forests. These species possess biological, conservational, and economic significance, all of which appear in danger of being lost.Los anfibios y reptiles de los bosques nublados constituyen el segmento más importante de la herpetofauna de Honduras, debido a la prevalencia de especies endémicas y restringidas a la Mesoamérica Nuclear. Este segmento, sin embargo, está sometido a fuertes amenazas medioambientales debido a acciones humanas. De las 334 especies de anfibios y reptiles que se conocen en Honduras en el presente, 122 se conocen que están distribuidas en las habitaciones de los bosques nublados. Las habitaciones del bosques nublados se encuentran a través de las montañas del interior de Honduras. Ellos están sujetos a un clima lluvioso de tierras altas, el cual tiene una precipitación anual de más de 1500 mm y una temperatura anual promedia de menos de 18 grados centígrados. La vegetación de los bosques nublados cae entre dos formaciones de Holdridge, la de Bosque Lluvioso Montano Bajo y la de Bosque Húmedo Montano Bajo. La formación de Bosque Lluvioso Montano Bajo generalmente occure a elevaciones en exceso de 1500 m, aunque puede ocurrir tan bajo como 1300 m en algunas localidades. La formación Bosque Húmedo Montano Bajo generalmente ocurre a 1700 m o más de elevación. De las 122 especies de los bosques nublados, 18 son salamandras, 38 son anuros, 27 son lagartijas y 39 son culebras. Noventa y ocho de estas 122 especies están distribuidas en la formación Bosque Lluvioso Montano Bajo y 45 en la formación Bosque Húmedo Montano Bajo. Viente especies están distribuidas en ambas formaciones. Las especies de los bosques nublados están distribuidas entre categorías distribucionales restringidas, amplias, y periféricas. Las especies restringidas se encuentra como grupo en un rango de elevaciones de los 1340 a los 2700 m, las especies que tienen una distribución amplia en al menos entre una de las dos formaciones de los bosques nublados como grupo tiene un rango desde el nivel del mar hasta 2744 m, y las especies periféricas como grupo tiene un rango desde el nivel del mar hasta 1980 m. Las 122 especies de los bosques nublados ejemplifican 10 patrones distribucionales amplios con rangos de especies para las cuales los rangos terminales norteño y sureño están en los Estados Unidos (o Canadá) y América del Sur, respectivamente, hasta esas especies que son endémicas de Honduras. El segmento más grande de la herpetofauna cae en la categoría endémica, con el proximo segmento más grande siendo restringido en distribución a la Mesoamérica Nuclear, pero no endémico de Honduras. Las especies de los bosques nublados están distribuidas entre ocho áreas ecofisiográficas, con el grupo más grande encontrandose en las tierras altas hacia el noroeste y seguido por las tierras altas norte-central y las tierras altas del suroeste. La importancia más grande de la herpetofauna hondureña cae en sus 125 especies que son endémicas de Honduras o de otra manera restringidas a la Mesoamérica Nuclear, de las cuales 83 están distribuidos en los bosques nublados del país. Este segmento de la herpetofauna está seriamente amenazado a consequencia de la destrucción exponencial de sus habitaciones, el cual es el resultado de la destrucción de los bosques, aunque existen varias reservas bióticas establecidas en los bosques nublados. Otros factores medioambientales menos claramente evidentes parecen estar implicados. Como consequencia, un poco más de la mitad de estas 83 especies (50.6%) tiene poblaciones que están disminuyendo o que han desaparecidos de los bosques nublados hondureños. Estas especies poseen significancia biológica, de conservación, y económica, todas las cuales parecen estar en peligro de ser perdidas

New Methods for Characterizing Phases of 2D Supersymmetric Gauge Theories

We study the physics of two-dimensional N=(2,2) gauged linear sigma models (GLSMs) via the two-sphere partition function. We show that the classical phase boundaries separating distinct GLSM phases, which are described by the secondary fan construction for abelian GLSMs, are completely encoded in the analytic structure of the partition function. The partition function of a non-abelian GLSM can be obtained as a limit from an abelian theory; we utilize this fact to show that the phases of non-abelian GLSMs can be obtained from the secondary fan of the associated abelian GLSM. We prove that the partition function of any abelian GLSM satisfies a set of linear differential equations; these reduce to the familiar A-hypergeometric system of Gel'fand, Kapranov, and Zelevinski for GLSMs describing complete intersections in toric varieties. We develop a set of conditions that are necessary for a GLSM phase to admit an interpretation as the low-energy limit of a non-linear sigma model with a Calabi-Yau threefold target space. Through the application of these criteria we discover a class of GLSMs with novel geometric phases corresponding to Calabi-Yau manifolds that are branched double-covers of Fano threefolds. These criteria provide a promising approach for constructing new Calabi-Yau geometries.Comment: 25 pages + references, appendices. v2: references added, typos corrected. v3: two small typos correcte