Studies of the mycoflora of some lead contaminated soils

An ecological study of the mycoflora of some lead contaminated soils was undertaken. Five soils were sampled bimonthly over a two year period. Two of the soils consisted of old mine 'Tailings', both of which had received an application of topsoil at some time. Two other soils were a result of the processing of the ore for marketing and the remaining soil sampled was part of an agricultural field nearby. The numbers of fungi found in all the soils sampled were appreciably lower than those in normal soils. This was so even in the agricultural field which did not contain so much lead as the other soils, but contained many more isolates/gram than the other soils. A wide variety of species was isolated from the soils but only a few were major contributors to the mycoflora. All species isolated have been found previously in soils to varying extents. There were some differences between the soils investigated and normal soils, but these were not in the kind of species but their relative numbers. However, the differences were not sufficient to give rise to a distinctive flora associated with lead soils. Two fungi in particular occurred more than in normal soils - Coniothyrium fuckelii and Phoma herbanun. The latter seemed to be an important member of the mycoflora of the spoil heaps. The soils were also studied for seasonal variation and the effect of depth. It was found that there was no apparent seasonal differences but numbers of both species and isolates were affected adversely by depth. In addition to the ecological studies the effect of lead on the growth of Aspergillus fumigatus Fres. was investigated. On solid media growth could occur at very high concentrations up to 1500 p.p.m. Most of the experiments were conducted using liquid media in which growth was prevented above 170 p.p.m. Germination of A. fumigatus spores can occur over a wide range of lead concentrations, but mycelial growth is much more limited. Tolerance of lead by the mycelium increases until after four days it has no effect on the growth of the mycelium. Lead would seem to be fungistatic rather than fungicidal, since it hinders growth but does not prevent it and once the lead is removed growth continues normally. In addition to the effect of lead on the growth of A. fumigatus isolates of some species from spoil and non lead-containing areas were compared for their ability to grow on lead-containing media. There was a varied reaction of the isolates which indicated that the fungal flora was composed of two types. One kind of fungus was normally lead tolerant while the other developed a higher lead tolerance in the spoil

Learning in the light of freedom: The Mississippi freedom schools of 1964

This paper investigates the “freedom schools” of the Mississippi Freedom Summer Project of 1964. It argues through a combination of a powerfully designed curriculum, the implementation of student-centered pedagogy, and a focus on relationship building and personal efficacy, freedom school students were given the skills and confidence needed to become young leaders in their communities and bring change to Mississippi. Through this paper, I hope to encourage current educators apply freedom school principles and practices in their own classrooms to inspire our students in the same way

Maternal Determinants and Early Diagnosis of Language Disorders

The speech, language, and hearing sciences are currently on the rise. These professionals–speech-language pathologists–focus on finding underlying communication impairments within individuals and then develop techniques for their assessments and treatments. They can assist anyone from small children with a fluency disorder such as a stutter to an adult who has recently experienced a stroke and is now suffering from dysarthria–slurred speech associated with an injury or muscle weakness. However, with this said, there is currently an issue with individuals, children primarily, getting an early language disorder diagnosis. In other words, several children with a language disorder are going unnoticed. An early diagnosis is vital because it can prevent children from falling behind their peers in school, and it increases the possibility that their language skills improve over time. Currently, there are assumptions that parents, primarily mothers, are key to an early diagnosis for their children. Thus, the main question of this project is: Is there a correlation between maternal determinants–awareness and access to resources–and the early diagnosis of language disorders? To answer this question, a literature review was conducted. Recent studies looking at children with language disorders and relating them to their mothers’ backgrounds were analyzed. Significant findings from these studies were noted and compared in an essay. It was found that children with language disorders are not being appropriately diagnosed due to a number of factors. The most significant factors were parents not being knowledgeable about the field of speech-language pathology and there not being optimal methods to guarantee an early diagnosis as of yet. It was also found that demographics played a role as well. Ultimately, there is much room for future research due to the lack of data on some language disorders and optimal methods for early diagnosis

Multi-waveband observations of colliding galaxies

Colliding galaxies represent a major challenge to both theorists and observers because of the large variety of phenomena which are expected to come into play during the interaction. Strong gravitational fluctuations may drive non-linear waves and instabilities throughout the stars and gas leading to enhanced star formation, nuclear activity and ultimately a mixing of the morphological components of the original galaxies. One relatively uncomplicated class of colliding galaxy where stellar waves play an important role in star formation are ring galaxies. Ring galaxies are probably formed when a companion galaxy passes through the center of a disk system driving circular waves through the disk (Lynds and Toomre 1976, Toomre 1978, Struck-Marcell 1990). Off-center collisions can generate non-circular waves and can be loosely described as banana-shaped although they may exhibit more complex forms as the waves expand into the disk. The propagation of such stellar and gaseous waves through the disk leads to enhanced star formation (e.g., Appleton and Struck-Marcell 1987a; Jeske 1986) and provides a unique probe of the response of the interstellar medium (ISM) to a propagating wave (see Appleton and Struck-Marcell 1987b). Here, the authors report results for 3 systems; the irregular ring Arp 143 (=VV 117); Wakamatsu's Seyfert ring (A0959-755; see Wakamatsu and Nishida 1987) and the brighter member of the pair of ring galaxies comprising of AM 1358-221. The most complete multi-wavelength data is for Arp 143. Optical charge coupled device (CCD) observations made with the 60 inch Palomar telescope at BV and r band, near-IR images at J (1.25 microns), H (1.65 microns) and k (2.2 microns) bands from the infrared camera (IRCAM) InSb array camera on the 3.8m United Kingdon Infrared Telescope (UKIRT) telescope and very large array (VLA) observations at 20cm in both the neutral hydrogen line and radio continuum are described. The observations of Wakamatsu's ring and AM 1358 were made only in the near-IR, and a comparison is made with available optical plate material

Enhanced dust heating in the bulges of early-type spiral galaxies

Stellar density and bar strength should affect the temperatures of the cool (T ~ 20–30 K) dust component in the inner regions of galaxies, which implies that the ratio of temperatures in the circumnuclear regions to the disk should depend on Hubble type. We investigate the differences between cool dust temperatures in the central 3 kpc and disk of 13 nearby galaxies by fitting models to measurements between 70 and 500 μm. We attempt to quantify temperature trends in nearby disk galaxies, with archival data from Spitzer/MIPS and new observations with Herschel/SPIRE, which were acquired during the first phases of the Herschel observations for the KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) sample. We fit single-temperature modified blackbodies to far-infrared and submillimeter measurements of the central and disk regions of galaxies to determine the temperature of the component(s) emitting at those wavelengths. We present the ratio of central-region-to-disk-temperatures of the cool dust component of 13 nearby galaxies as a function of morphological type. We find a significant temperature gradient in the cool dust component in all galaxies, with a mean center-to-disk temperature ratio of 1.15 ± 0.03. The cool dust temperatures in the central ~3 kpc of nearby galaxies are 23 (±3)% hotter for morphological types earlier than Sc, and only 9 (±3)% hotter for later types. The temperature ratio is also correlated with bar strength, with only strongly barred galaxies having a ratio over 1.2. The strong radiation field in the high stellar density of a galactic bulge tends to heat the cool dust component to higher temperatures, at least in early-type spirals with relatively large bulges, especially when paired with a strong bar

Bessie on the Board Walk

https://digitalcommons.library.umaine.edu/mmb-vp/4685/thumbnail.jp

Observations and modeling of the dust emission from the H_2-bright galaxy-wide shock in Stephan's Quintet

Context. Spitzer Space Telescope observations have detected powerful mid-infrared (mid-IR) H_2 rotational line emission from the X-ray emitting large-scale shock (~15 × 35 kpc^2) associated with a galaxy collision in Stephan's Quintet (SQ). Because H_2 forms on dust grains, the presence of H_2 is physically linked to the survival of dust, and we expect some dust emission to originate in the molecular gas. Aims. To test this interpretation, IR observations and dust modeling are used to identify and characterize the thermal dust emission from the shocked molecular gas. Methods. The spatial distribution of the IR emission allows us to isolate the faint PAH and dust continuum emission associated with the molecular gas in the SQ shock. We model the spectral energy distribution (SED) of this emission, and fit it to Spitzer observations. The radiation field is determined with GALEX UV, HST V-band, and ground-based near-IR observations. We consider two limiting cases for the structure of the H_2 gas: it is either diffuse and penetrated by UV radiation, or fragmented into clouds that are optically thick to UV. Results. Faint PAH and dust continuum emission are detected in the SQ shock, outside star-forming regions. The 12/24 μm flux ratio in the shock is remarkably close to that of the diffuse Galactic interstellar medium, leading to a Galactic PAH/VSG abundance ratio. However, the properties of the shock inferred from the PAH emission spectrum differ from those of the Galaxy, which may be indicative of an enhanced fraction of large and neutrals PAHs. In both models (diffuse or clumpy H_2 gas), the IR SED is consistent with the expected emission from dust associated with the warm (> 150 K) H_2 gas, heated by a UV radiation field of intensity comparable to that of the solar neighborhood. This is in agreement with GALEX UV observations that show that the intensity of the radiation field in the shock is GUV = 1.4±0.2 [Habing units]. Conclusions. The presence of PAHs and dust grains in the high-speed (~1000 km s^(-1)) galaxy collision suggests that dust survives. We propose that the dust that survived destruction was in pre-shock gas at densites higher than a few 0.1 cm^(-3), which was not shocked at velocities larger than ~200 km s^(-1). Our model assumes a Galactic dust-to-gas mass ratio and size distribution, and current data do not allow us to identify any significant deviations of the abundances and size distribution of dust grains from those of the Galaxy. Our model calculations show that far-IR Herschel observations will help in constraining the structure of the molecular gas, and the dust size distribution, and thereby to look for signatures of dust processing in the SQ shock

Modelling positive consequences: Increased vegetable intakes following modelled enjoyment versus modelled intake.

OBJECTIVE: Modelling has previously been demonstrated to encourage healthy eating, but the importance of modelling the behaviour versus modelling the positive consequences of the behaviour is unknown. This work investigated the impact of modelling carrot intake (the behaviour) and modelling carrot enjoyment (the positive consequences) on subsequent liking and consumption of carrots and sweetcorn. METHODS: 155 children aged 7-10 years were randomized to hear a story where fictional characters consumed a picnic with either: no mention of carrot sticks (control) (N = 45); mention of carrot sticks that all characters ate (modelling intake) (N = 60); or mention of carrot sticks that the characters like (modelling enjoyment) (N = 50). Carrot and sweetcorn liking and intake were measured before and after the story during a 5 min task. RESULTS: Carrot liking and intake after a story was higher following the story modelling carrot enjoyment compared to the stories not modelling enjoyment (smallest β = 0.16, p = 0.05), and in those with higher pre-story carrot liking and intakes (smallest β = 0.25, p < 0.01). Sweetcorn liking and intake after a story was associated with pre-story sweetcorn liking and intake (smallest β = 0.28, p < 0.01), and sweetcorn intake was lower following the story modelling carrot enjoyment compared to the stories not modelling enjoyment (β = -0.17, p = 0.04). CONCLUSIONS: These findings demonstrate a role for modelling enjoyment to encourage vegetable liking and intake, although effects sizes were small. These findings also suggest a benefit from modelling the positive consequences of a behaviour for encouraging healthy food intake in children, while limited effects were found for modelling the behaviour itself