Accessing Background Knowledge To Build Mathematical Vocabulary

This paper examines the benefits of accessing knowledge to build background knowledge in mathematics. Various methods of vocabulary instruction are explained and examined. Research of vocabulary instruction in math speaks to the need for educators to explicitly teach vocabulary in adding to skills if order for students to develop as mathematicians. An elementary school classroom teacher examined two mathematical units, one with clear vocabulary teaching and one without a focus on vocabulary. The data demonstrates the benefits of explicit vocabulary instruction as student achievement raised 39% on end of unit assessments

Direct observations of the atmospheric processing of Asian mineral dust

The accumulation of secondary acids and ammonium on individual mineral dust particles during ACE-Asia has been measured with an online single-particle mass spectrometer, the ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles correlate with air masses from different source regions. The uptake of secondary acids depended on the individual dust particle mineralogy; high amounts of nitrate accumulated on calcium-rich dust while high amounts of sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV) to S(VI) by iron in the aluminosilicate dust is a possible explanation for this enrichment of sulphate, which has important consequences for the fertilization of remote oceans by soluble iron. This study shows the segregation of sulphate from nitrate and chloride in individual aged dust particles for the first time. A transport and aging timeline provides an explanation for the observed segregation. Our data suggests that sulphate became mixed with the dust first. This implies that the transport pathway is more important than the reaction kinetics in determining which species accumulate on mineral dust. Early in the study, dust particles in volcanically influenced air masses were mixed predominately with sulphate. Dust mixed with chloride then dominated over sulphate and nitrate when a major dust front reached the R. V. Ronald Brown. We hypothesize that the rapid increase in chloride on dust was due to mixing with HCl(g) released from acidified sea salt particles induced by heterogeneous reaction with volcanic SO₂(g), prior to the arrival of the dust front. The amount of ammonium mixed with dust correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent reports that they exist as external mixtures. The size distribution of the mixing state of dust with these secondary species validates previous mechanisms of the atmospheric processing of dust and generally agrees with simulated aerosol chemistry from the STEM-2K3 model. This series of novel results has important implications for improving the treatment of dust in global chemistry models and highlights a number of key processes that merit further investigation through laboratory and field studies

Direct observations of the atmospheric processing of Asian mineral dust

International audienceThe accumulation of secondary acids and ammonium on individual mineral dust particles during ACE-Asia has been measured with an online single-particle mass spectrometer, the ATOFMS. Changes in the amounts of sulphate, nitrate, and chloride mixed with dust particles correlate with air masses from different source regions. The uptake of secondary acids depended on the individual dust particle mineralogy; high amounts of nitrate accumulated on calcium-rich dust while high amounts of sulphate accumulated on aluminosilicate-rich dust. Oxidation of S(IV) to S(VI) by iron in the aluminosilicate dust is a possible explanation for this enrichment of sulphate, which has important consequences for the fertilization of remote oceans by soluble iron. This study shows the segregation of sulphate from nitrate and chloride in individual aged dust particles for the first time. A transport and aging timeline provides an explanation for the observed segregation. Our data suggests that sulphate became mixed with the dust first. This implies that the transport pathway is more important than the reaction kinetics in determining which species accumulate on mineral dust. Early in the study, dust particles in volcanically influenced air masses were mixed predominately with sulphate. Dust mixed with chloride then dominated over sulphate and nitrate when a major dust front reached the R. V. Ronald Brown. We hypothesize that the rapid increase in chloride on dust was due to mixing with HCl(g) released from acidified sea salt particles induced by heterogeneous reaction with volcanic SO2(g), prior to the arrival of the dust front. The amount of ammonium mixed with dust correlated strongly with the total amount of secondary acid reaction products in the dust. Submicron dust and ammonium sulphate were internally mixed, contrary to frequent reports that they exist as external mixtures. The size distribution of the mixing state of dust with these secondary species validates previous mechanisms of the atmospheric processing of dust and generally agrees with simulated aerosol chemistry from the STEM-2K3 model. This series of novel results has important implications for improving the treatment of dust in global chemistry models and highlights a number of key processes that merit further investigation through laboratory and field studies

The Effect of Soil Moisture on the Susceptibility to Invasion by the Argentine Ant (Linepithema humile) in Chaparral Communities.

The Argentine ant (Linepithema humile) is a successful invasive species found throughout the world. It is commonly associated with urban areas and invades habitats that have favorable conditions, such as adequate moisture levels. Urban areas in the xeric regions of Southern California that use supplemental irrigation create artificially moist habitats that are thought to serve as a permanent refuge for the Argentine ant. Invasion is a three step process of introduction, establishment, and spread; for Argentine ants to invade, they must first be introduced to an area. This study was designed to determine if Argentine ants seasonally spread into habitats that have high soil moisture for only a portion of the year, and to access the role that soil moisture, seasonality, proximity to the urban edge, and proximity to a permanent water source play in determining which areas the Argentine ant will spread into, and where they are likely to successfully invade. This study examined three different habitat types on two reserves that differed in water availability: mesic (permanently wet), xeric (upland areas without a permanent water source), and seasonally moist (intermittently wet). Sampling cups were set out in each habitat during the wet and dry season for a period of two years. Measurements were taken on Argentine ant abundance, native ant species abundance, distance to the urban edge, and distance to a permanent water source. Argentine ants were found in mesic sites throughout the study period in both wet and dry seasons. No Argentine ants were found at the xeric sites in either wet or dry seasons. Out of six seasonally moist sites, one that was in close proximity to permanent water had Argentine ants year round, while the other seasonally moist sites had no Argentine ants. Distance to a permanent water source was the best predictor for Argentine ant abundance, followed by soil moisture. Seasonal spreading was not observed in any habitat type. Based on these findings, intermittent water does not seem to be a risk factor for Argentine ant invasion, but permanent water is a risk factor for invasion. Dry-season urban runoff will potentially lead to increased Argentine ant invasions in this region

Amebiasis

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44376/1/10620_2005_Article_BF02233792.pd