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

Sinks in Acyclic Orientations of Graphs

Greene and Zaslavsky proved that the number of acyclic orientations of a graph with a unique sink is, up to sign, the linear coefficient of the chromatic polynomial. We give three new proofs of this result using pure induction, noncommutative symmetric functions, and an algorithmic bijection.Comment: 17 pages, 1 figur

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)

Robust statistics for deterministic and stochastic gravitational waves in non-Gaussian noise I: Frequentist analyses

Gravitational wave detectors will need optimal signal-processing algorithms to extract weak signals from the detector noise. Most algorithms designed to date are based on the unrealistic assumption that the detector noise may be modeled as a stationary Gaussian process. However most experiments exhibit a non-Gaussian ``tail'' in the probability distribution. This ``excess'' of large signals can be a troublesome source of false alarms. This article derives an optimal (in the Neyman-Pearson sense, for weak signals) signal processing strategy when the detector noise is non-Gaussian and exhibits tail terms. This strategy is robust, meaning that it is close to optimal for Gaussian noise but far less sensitive than conventional methods to the excess large events that form the tail of the distribution. The method is analyzed for two different signal analysis problems: (i) a known waveform (e.g., a binary inspiral chirp) and (ii) a stochastic background, which requires a multi-detector signal processing algorithm. The methods should be easy to implement: they amount to truncation or clipping of sample values which lie in the outlier part of the probability distribution.Comment: RevTeX 4, 17 pages, 8 figures, typos corrected from first version

Private money creation and the Suffolk Banking System

Electronic commerce ; Money

Counting (3+1) - Avoiding permutations

A poset is {\it (\3+\1)-free} if it contains no induced subposet isomorphic to the disjoint union of a 3-element chain and a 1-element chain. These posets are of interest because of their connection with interval orders and their appearance in the (\3+\1)-free Conjecture of Stanley and Stembridge. The dimension 2 posets $P$ are exactly the ones which have an associated permutation $\pi$ where $i\prec j$ in $P$ if and only if $i<j$ as integers and $i$ comes before $j$ in the one-line notation of $\pi$. So we say that a permutation $\pi$ is {\it (\3+\1)-free} or {\it (\3+\1)-avoiding} if its poset is (\3+\1)-free. This is equivalent to $\pi$ avoiding the permutations 2341 and 4123 in the language of pattern avoidance. We give a complete structural characterization of such permutations. This permits us to find their generating function.Comment: 17 page

Understanding the Recovery Process in Psychosis

Conceptualizing recovery in the context of severe and persisting mental health conditions is a complex issue. In recent years, there has been a call to re-focus research from understanding the concept of recovery to improving understanding of the process of recovery. There is a paucity of knowledge about the core processes involved in recovery from psychosis. Objective: The authors aimed to gain insight into possible processes involved in recovery through analyzing data generated from a large qualitative study investigating employment barriers and support needs of people living with psychosis. Research Design and Methods: Participants were 137 individuals drawn from six key stakeholder groups. Data obtained from focus groups (14) and individual interviews (34) were analyzed using thematic analysis. Results: The main recovery processes identified were: learning effective coping strategies; recognizing personal potential; identifying and realizing personal goals; participation in social and occupational roles; positive risk-taking; and reclaiming personal identity. Discussion: The results of this study have implications for treatment as well as the daily support needs of people recovering from psychosis

The Suffolk Bank and the Panic of 1837

The Suffolk Bank in Boston is well known as having been the clearinghouse for virtually all the banknotes that circulated in New England between 1836 and 1858. An examination of 19th century bank balance sheets shows that during and after the U.S. banking Panic of 1837, this private commercial bank also provided some services that today are provided by central banks. These include lending reserves to other banks (providing a discount window) and keeping the payments system operating. Because of Suffolk's activities, banks in New England fared better than banks elsewhere during the Panic of 1837. And after the panic, when much of the United States suffered a prolonged economic slowdown, New England fared better than the rest of the country, at least partly because of Suffolk’s central bank-like activities.Bank notes ; Banks and banking - History