An ecological study of Chinese privet (Ligustrum sinense Lour.) in the Waikato Region

Chinese privet (Ligustrum sinense) has naturalised across the Waikato region invading lowland native forest and wetland habitat. This shrub has the ability to form a dense canopy or subcanopy and appears to exclude other native species from establishing in the understorey. Chinese privet seedlings were found in abundance underneath privet canopy, where they grow slower than when invading a new site yet are able to succeed adult plants and continually occupy a site. Chinese privet seedlings establish readily under intact native canopy but are more prolific in disturbed high light environments. Fruit is produced in abundance and is dispersed by birds particularly beneath perch sites, which limits seed dispersal over open ground. Chinese privet seedlings appear to be palatable to stock, but rapidly out-compete and dominate regenerating native species when grazing pressure is removed. A short-lived seedbank, six months to one year viability, suggests that the removal of adult plants will quickly reduce the number of seedlings establishing. This invasive shrub is a serious weed in south-eastern USA where it is well established and would appear to have similar potential in New Zealand to form vast, dense thickets with very low floristic diversity

Detecting hydrogen-containing contaminants on metal surfaces

Spark emission spectroscopy analyzes surface contamination of metals. This technique controls the quality of surface preparations and is useful in fundamental investigations of surface properties of metals

Waiwhakareke Restoration Plantings: Establishment of Monitoring Plots 2005-06

Waiwhakareke Natural Heritage Park is being developed to reconstruct native lowland and wetland ecosystems as were once widespread in the Waikato Region. The 60ha Natural Heritage Park is located on the north-west outskirts of Hamilton City and includes a peat lake (Horseshoe Lake) which is surrounded by introduced willow trees. There is some native marginal vegetation around the lake, including rushes and sedges, and an extensive area of gently sloping pasture completes the catchment. The restoration and recreation of the native plant and animal communities is being lead by the Hamilton City Council in partnership with The University of Waikato, Wintec, Nga Mana Toopu o Kirikiriroa Limited Resource Management and Cultural Consultants and Tui 2000 (McQueen 2005; McQueen & Clarkson 2003)

Portable spectrometer monitors inert gas shield in welding process

Portable spectrometer using photosensitive readouts, monitors the amount of oxygen and hydrogen in the inert gas shield of a tungsten-inert gas welding process. A fiber optic bundle transmits the light from the welding arc to the spectrometer

Modeling the Pulse Profiles of Millisecond Pulsars in the Second LAT Catalog of gamma-ray Pulsars

Significant gamma-ray pulsations have been detected from ~40 millisecond pulsars (MSPs) using 3 years of sky-survey data from the Fermi LAT and radio timing solutions from across the globe. We have fit the radio and gamma-ray pulse profiles of these MSPs using geometric versions of slot gap and outer gap gamma-ray emission models and radio cone and core models. For MSPs with radio and gamma-ray peaks aligned in phase we also explore low-altitude slot gap gamma-ray models and caustic radio models. The best-fit parameters provide constraints on the viewing geometries and emission sites. While the exact pulsar magnetospheric geometry is unknown, we can use the increased number of known gamma-ray MSPs to look for significant trends in the population which average over these uncertainties.Comment: 4 pages, 2 figures, to appear in the proceedings of the 5th International Symposium on High-Energy Astronom

Genetic Landscape of Pediatric Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are acquired heterogeneous hematopoietic clonal disorders primarily seen in the adult and elderly populations that presents a variety of cellular morphologies in cell lineages, varying prognoses, and differences in overall survival (OS) between individual patients. The occurrence of MDS in the pediatric and young adult population, or those between the ages of 0 and 29, is slowly on the rise. Pediatric and elderly cases exhibit diverse cytogenetic findings with differences in OS. The characterization of the genetic landscape of pediatric MDS is limited and most studies detailing genetic changes have been conducted in adult MDS cases. In order to aid in therapeutic stratification for pediatric cases, the key genes involved in hematopoietic transformation must be deciphered. This study utilized comprehensive analysis including cytogenetic karyotyping, FISH, and high-resolution microarray techniques. With the use of multiple techniques, this study confirmed the rarity of MDS in the pediatric population, characterized the frequencies of hallmark cytogenetic abnormalities, and identified key aberrations observed at the genetic level. With the use of microarray, we were able to detect genomic aberrations in 33 genes including novel copy number changes in more than one case in the PRDM16, IRF4, MYH11, ALK, CDKN2B, PAX5, EXT2, and ERCC4 genes. The results from this study prove the importance of comprehensive testing utilizing a variety of techniques in distinguishing the most accurate genetic landscape of pediatric MDS. This information can be used to better equip the medical community in accurately diagnosing and providing prognostic implications for therapy and treatment

Single wall carbon nanotube double quantum dot

We report on two top-gate defined, coupled quantum dots in a semiconducting single wall carbon nanotube, constituting a tunable double quantum dot system. The single wall carbon nanotubes are contacted by titanium electrodes, and gated by three narrow top-gate electrodes as well as a back-gate. We show that a bias spectroscopy plot on just one of the two quantum dots can be used to extract the addition energy of both quantum dots. Furthermore, honeycomb charge stability diagrams are analyzed by an electrostatic capacitor model that includes cross capacitances, and we extract the coupling energy of the double quantum dot.Comment: Published in Applied Physics Letters 4 December 2006. http://link.aip.org/link/?APL/89/23211

Design, development, and fabrication of a portable spectrometer-type monitor Technical summary report, Jun. 29, 1964 - Jan. 31, 1966

Portable spectrometer for monitoring oxygen and hydrogen as free gas or as dissociation products in inert gas shield of gas tungsten arc welding proces