The ability of fifth grade children to discriminate between fact and opinion statement

Thesis (Ed.M.)--Boston Universit

Habitat partitioning between woodland caribou and moose in Ontario: the potential role of shared prédation risk

This paper explores mechanisms of coexistence for woodland caribou (Rangifer tarandus caribou) and moose (Akes alces) preyed upon by gray wolves (Canis lupus) in northern Ontario. Autocorrelation analysis of winter track locations showed habitat partitioning by caribou and moose. Numbers of Delaunay link edges for moose-wolves did not differ significantly from what would be expected by random process, but those for caribou-wolves were significantly fewer. Thus, habitat partitioning provided implicit refuges that put greater distances between caribou and wolves, presumably decreasing predation on the caribou. Yet, direct competition cannot be ruled out; both apparent and direct competition may be involved in real-life situations. A synthesis including both explanations fits ecological theory, as well as current understanding about caribou ecology

EFFICACY TEST PROTOCOLS FOR EVALUATION OF ULTRASONIC RODENT REPELLENT DEVICES

Controlled laboratory and field test protocols were developed to assess the repellent efficacies of six commercially manufactured ultrasonic rodent repellent devices. The laboratory test structure (68.7 sq m) was divided into two rooms (32.5 sq m each) with a central harborage area (3.5 sq m) containing a colony of 12 wild Norway rats (Rattus norvegicus). For each test, a single ultrasonic device was attached to the far end of one room and rat activity measures (oat consumption, packet damage, photocell counts) were taken during 1-week baseline and 2-1/2-week test periods. Field test structures varied in floor area (6.5 to 197 sq m) and were of either metal or wood construction. All contained existing Norway rat, house mouse (Mus musculus), or field mouse (Peromyscus maniculatus) infestations. No rodent control was conducted at these sites other than the application of selected ultrasonic devices. Rodent activity (packet damage, food consumption, rodent tracks) was measured twice per week during three successive 3-week intervals with devices operating only during the second interval. Repeated measures analysis of variance and chi square were used to statistically evaluate the reliability of ultrasound effects

Production, purification, sequencing and activity spectra of mutacins D-123.1 and F-59.1

<p>Abstract</p> <p>Background</p> <p>The increase in bacterial resistance to antibiotics impels the development of new anti-bacterial substances. Mutacins (bacteriocins) are small antibacterial peptides produced by <it>Streptococcus mutans </it>showing activity against bacterial pathogens. The objective of the study was to produce and characterise additional mutacins in order to find new useful antibacterial substances.</p> <p>Results</p> <p>Mutacin F-59.1 was produced in liquid media by <it>S. mutans </it>59.1 while production of mutacin D-123.1 by <it>S. mutans </it>123.1 was obtained in semi-solid media. Mutacins were purified by hydrophobic chromatography. The amino acid sequences of the mutacins were obtained by Edman degradation and their molecular mass was determined by mass spectrometry. Mutacin F-59.1 consists of 25 amino acids, containing the YGNGV consensus sequence of pediocin-like bacteriocins with a molecular mass calculated at 2719 Da. Mutacin D-123.1 has an identical molecular mass (2364 Da) with the same first 9 amino acids as mutacin I. Mutacins D-123.1 and F-59.1 have wide activity spectra inhibiting human and food-borne pathogens. The lantibiotic mutacin D-123.1 possesses a broader activity spectrum than mutacin F-59.1 against the bacterial strains tested.</p> <p>Conclusion</p> <p>Mutacin F-59.1 is the first pediocin-like bacteriocin identified and characterised that is produced by <it>Streptococcus mutans</it>. Mutacin D-123.1 appears to be identical to mutacin I previously identified in different strains of <it>S. mutans</it>.</p

Advances in high-throughput, high-capacity nonwoven membranes for chromatography in downstream processing: A review

: Nonwoven membranes are highly engineered fibrous materials that can be manufactured on a large scale from a wide range of different polymers, and their surfaces can be modified using a large variety of different chemistries and ligands. The fiber diameters, surface areas, pore sizes, total porosities, and thicknesses of the nonwoven mats can be carefully controlled, providing many opportunities for creative approaches for the development of novel membranes with unique properties to meet the needs of the future of downstream processing. Fibrous membranes are already finding use in ultrafiltration, microfiltration, depth filtration, and, more recently, in membrane chromatography for product capture and impurity removal. This article summarizes the various methods of manufacturing nonwoven fabrics, and the many methods available for the modification of the fiber surfaces. It also reviews recent studies focused on the use of nonwoven fabric devices in membrane chromatography and provides some perspectives on the challenges that need to be overcome to increase binding capacities, decrease residence times, and reduce pressure drops so that eventually they can replace resin column chromatography in downstream process operations