Walker Complex (April 2002)

The complex was comprised of the new Student/Community Health and Fitness Centre and the state-of-the-art health club called The Zone, in addition to encompassing the existing physical education facilities. Among the new facilities was a 23 000-square-foot gymnasium, which boasted four basketball courts and a 200-meter, three-lane elevated track. The building was named after Walker Industries Holdings, a Thorold firm that was the key donor to the project.

Cloning, sequencing and characterization of a chitin synthase gene fragment from the fungus Phascolomyces articulosus /

Phascolomyces articulosus genomic DNA was isolated from 48 h old hyphae and was used for amplification of a chitin synthase fragment by the polymerase chain reaction method. The primers used in the amplification corresponded to two widely conserved amino acid regions found in chitin synthases of many fimgi. Amphfication resulted in four bands (820, 900, 1000 and 1500 bp, approximately) as visualized in a 1.2% agarose gel. The lowest band (820 bp) was selected as a candidate for chitin synthase because most amplified regions from other fimgi so far exhibited similar sizes (600-750 bp). The selected fragment was extracted from the gel and cloned in the Hinc n site of pUC19. The derived plasmid and insert were designated ^\5C\9'PaCHS and PaCHS respectively. The plasmid pUC19-PaC/fS was digested by several restriction enzymes and was found to contain BamHl and HincU sites. Sequencing of PaCHS revealed two intron sequences and a total open reading frame of 200 amino acids. The derived polypeptide was compared with other related sequences from the EMBL database (Heidelberg, Germany) and was matched to 36 other fiilly or partially sequenced fimgal chitin synthase genes. The closest resemblance was with two genes (74.5% and 73.1% identity) from Rhizopus oligosporus. Southern hybridization with the cloned fragment as a probe to the PCR reaction showed a strong signal at the fragment selected for cloning and weaker signals at the other two fragments. Southern hybridization with partially digested Phascolomyces articulosus genomic DNA showed a single band. The amino acid sequence was compared with sequences from other chitin synthase gene classes using the CLUSTALW program. The chitin synthase fragment from Phascolomyces articulosus was initially grouped in class n along with chitin synthase fragments from Rhizopus oligosporus and Phycomyces blakesleeanus which also belong to the same class, Zygomycetes. Bootstrap analysis using the neighbor-joining method available by CLUSTALW verified such classification. Comparison of PaCHS revealed conservation of intron positions that are characteristic of chitin synthase gene fragments of zygomycetous fungi.

Geological image processing of petrographic thin sections using the rotating polarizer stage

One of the fundamental problems with image processing of petrographic thin sections is that the appearance (colour I intensity) of a mineral grain will vary with the orientation of the crystal lattice to the preferred direction of the polarizing filters on a petrographic microscope. This makes it very difficult to determine grain boundaries, grain orientation and mineral species from a single captured image. To overcome this problem, the Rotating Polarizer Stage was used to replace the fixed polarizer and analyzer on a standard petrographic microscope. The Rotating Polarizer Stage rotates the polarizers while the thin section remains stationary, allowing for better data gathering possibilities. Instead of capturing a single image of a thin section, six composite data sets are created by rotating the polarizers through 900 (or 1800 if quartz c-axes measurements need to be taken) in both plane and cross polarized light. The composite data sets can be viewed as separate images and consist of the average intensity image, the maximum intensity image, the minimum intensity image, the maximum position image, the minimum position image and the gradient image. The overall strategy used by the image processing system is to gather the composite data sets, determine the grain boundaries using the gradient image, classify the different mineral species present using the minimum and maximum intensity images and then perform measurements of grain shape and, where possible, partial crystallographic orientation using the maximum intensity and maximum position images.

Reproduction in the temperate crayfish, Orconectes rusticus: intermale aggression, copulatary behaviour, and sperm competition

The chelipeds of Orconectes rusticus are sexually dimorphic; males possessing the larger. Males use their chelae in intermale aggressive interactions, both to threaten, and assault opponents. In dyadic interactions males with larger chelae were dominant over otherwise physically similar opponents. A high frequency of attack behaviour, coupled with a low frequency of threats during these interactions indicates that actual physical contact is required for opponent assessment. Large clawed males oriented females into the copulatory position faster than small clawed males. Females more frequently escaped the precopulatory-grasp attempts of small clawed males. Additionally, male-female pairs that included a large clawed male remained in copula longer than pairs that included a small clawed male. Sperm of the second male to mate took precedence over the sperm of the primary male. Sperm precedence was incomplete; about 900/0 paternity accrued to the second male.

The diffusion of Co⠶溩 Zrâ â Tiâ â alloy /|nS. Kumar. -- 260 St Catharines [Ont.] : Dept. of Physics, Brock University,

The diffusion of Co60 in the body centered cubic beta phase of a ZrSOTi SO alloy has been studied at 900°, 1200°, and 1440°C. The results confirm earlier unpublished data obtained by Kidson17 • The temperature dependence of the diffusion coefficient is unusual and suggests that at least two and possibly three mechanisms may be operative Annealing of the specimen in the high B.C.C. region prior to the deposition of the tracer results in a large reduction in the diffusion coefficient. The possible significance of this effect is discussed in terms of rapid transport along dislocation network.

The use of diatom assemblages to determine paleotrophic changes in lakes

The purpose of this study was to develop a classifi cation scheme for l ake trophic status based on the relative abundance of l ake sediment diatom trophic indicator species. A total of 600 diatom frustules were counted from the surface sediments of e a ch of 30 lakes selected to repr e seni~ a continuum from u.lt ra-oligotrophic t,o fairly eutrophic but not hype r-' eutrophic conditions. Published autecological information was used to determine the trophic indicator status of each of the s pecies. A quotieht was derived by dividing the s um of all the e utrophic indicator species by the sum of all oligotrophic indicai.-:.or species. Oligo'- mesotrophic. mesotrophic and meso-eutrophic species were added to both the numerator and denomina tor. Five categories of diatom i.nferred trophic status were recognized : ultra-oligotrophic - 0'-0.2:3, oligotrophic::: 0.24-0 . 70, mesotrophic :: 0.'71 -0.99, meso-elxtrophic :: 1. 00-1. '78 and eutrophic:: 1.. 79-2. 43. But only three of these (oligotrophic:: 0-0.69, mesotrophic ::: 0 . 70'-1.69 j and eutrophic:: 1.70-2.50) proved usef ul. The present study of the relationship between diatom inferred trophic status and the literature-derived trophic status of SO lake s (which were purposely chosen to represent a broad spectrum of lakes in Canada) indicated that: 1) Based on diatom species (assemblages ) it is possible to segregate the lakes from which. th",)se diatoms were taken into three basic categories : o ligotrophic, mesotrophic and eutrophic lake types. ~~) It was not possible t,o separate meso-eutrophic and o l igo-mesotrophic lakes f rom mesotrophic l akes as the the degree of overlap betwee n the diat,om species in these lake types was extremely high. 3) Ha d mo r e ul tra-oligotroph,ic lakes been sampled it might have been possible to more a ccurately s eparate them f rom oligotrophic Jakes. 4 ) Had. more humic lakes been sampled in this s tudy I f eel it would have been possible to identify a unique diatom a ssemblage which would h a ve chara cterized t his lake type . Re gression analyses were performed using the aforementioned diatom inferred trophic index as a f unction of 1) log Sec chi transparency (r = - 0.70) 2) total phosphorus (r = 0. 77 ) and 3) chlorophyll-a (r = 0.74). Once e ach of these rel ationships had been established , it was possible to infer paleotrophic (downcore) changes in an oligotrophic lake (Barbara Lake) and in a eutrophic lake (Chemung Lake) . Barbara Llake was dominated by oligotrophic s pecies and remained oligotrophic throughout the 200-·year history r epresented by i t s 32 em long sediment core. Chemung Lake is currently dominated. by eutrophic species but went through a mesotrophic st,age which was associated with a rise in the water level of the lake followi n g dam construction in its watershed in the early 1.900 J ::;. This was followed by its reversion to it,s present day eutrophic stage (dominated by eutrophic species) possibly as a r esult of shallowing process which can be attributed to " silting' up" of the reservoir and the invasion of the l ake by Myriophyllum spjcatum (Eurasian milfoil) i n the 1970's . In addition, nutrient .:r':l.ch run"'offwhich resulted from increased human a.ctivities associated with cottage development along its shores has contribut ed to its eutrophication. There is some evidence that the rat,e o :f its prog ressive eutrophication has declined during the last decade. This was correlated with legislation enacted in the 60's and 70's in Ontario which was aimed at reducing nutrient loading from cottages.

The effects of the menstrual cycle and hormonal contraceptives on the central thermoeffector threshold temperatures and width of the interthreshold zone

Basal body temperature (BBT) and thermoeffector thresholds increase following ovulation in many women. This study investigated if solely central thermoregulatory alterations are responsible. Seven females in a non-contraceptive group (NCG) were compared with 5 monophasic contraceptive users (HCG) on separate accounts: pre-ovulation (Trial I; d 2-5) and post-ovulation (Trial 2; 4-8 d post-positive ovulation) for NCG, and active phase for HCG (d 2-5, d 18-21). During immersion in 28°C water to the axilla, participants exercised for 20-30 min on an underwater ergometer. After steadily sweating, immersion continued until metabolism increased two-fold due to shivering. Rectal (Tre) BBT was not different between trials for neither NCG (1: 37.34±0.16°C; 2: 37.35±0.27°C) nor HCG. At exercise termination, Tre forehead sweating cessation increased (P<0.05) in trial 2 irrespective of group (1: 37.55±0.39°C; 2: 37.90±0,46°C). Tre shivering onset did not increase (P>0.05) in trial 2 (1: 36.91±0.50°C; 2: 37.07±0,45°C). The widths of the interthreshold zone increased (P<0.05) in trial 2 (1: 0.64±0.22°C; 2: 0.82±0.37°C) due to the increased sweating threshold only. HCG cooled quicker (1: -l.15±0,43°C; 2: -1.00±0.50°C) than NCG participants (1: - 0.58±0.22°C; 2: -0.52±O.29°C), and tympanic (Tty) sweat thresholds were significantly (P<0.05) decreased (1: 34.76±0.54°C; 2: 35.39±0.61°C) versus NCG (l: 35.57±0.77°C; 2: 35.89±1.04°C). Lastly, Tre and Tty thresholds were significantly different (P

Electronic, magnetic and thermal properties of Pb₂₋x AxCrO₅ (A = K or La)

Lead chromium oxide is a photoconductive dielectric material tha t has great potential of being used as a room temperature photodetector. In this research, we made ceramic pellets of this compound as well as potassium doped compound Pb2-xKxCr05, where x=O, 0.05, 0.125. We also investigate the properties of the lanthanum doped sample whose chemical formula is Pb1.85Lao.15Cr05' The electronic, magnetic and thermal properties of these materials have been studied. Magnetization measurements of the Pb2Cr05 sample indicate a transition at about 310 K, while for the lanthanum doped sample the transition temperature is at about 295 K indicating a paramagnetic behavior. However, the potassium doped samples are showing the transition from paramagnetic state to diamagnetic state at different temperatures for different amounts of potassium atoms present in the sample. We have studied resistivity as a function of temperature in different gas environments from 300 K to 900 K. The resistivity measurement of the parent sample indicates a conducting to insulating transition at about 300 K and upon increasing the temperature further, above 450 K the sample becomes an ionic conductor. As temperature increases a decrease in resistance is observed in the lanthanum/potassium doped samples. Using Differential Scanning Calorimetry experiment an endothermic peak is observed for the Pb2Cr05 and lanthanum/potassium doped samples at about 285 K.

A Notorial Transumpt, 1497

Govan was an ancient settlement, former burgh and now a district in Glasgow, Scotland. It is situated 2.5 miles west of Glasgow City Centre, on the south bank of the River Clyde, opposite the mouth of the River Kelvin and the district of Patrick. Archaeological evidence shows that there was a church and burial ground here as early as 600-800 AD. Numerous carved tombstones dating from 900- 1100 have been found. Govan was a village comprised of thatched cottages until well into the 19th century. It became a shipbuilding town in the early 19th century.