Incidence of Extra-Floral Nectaries and their Effect on the Growth and Survival of Lowland Tropical Rain Forest Trees

Received the best poster in Organismal Biology award at the NMS Undergraduate Research ForumMutualistic relationships between organisms have long captivated biologists, and extra-floral nectaries (EFNs), or nectar-producing glands, found on many plants are a good example. The nectar produced from these glands serves as food for ants which attack intruders that may threaten their free meal, preventing herbivory. However, relatively little is known about their impact on the growth and survival of plants that exhibit EFNs. To better understand the ecological significance of EFNs, I examined their incidence on 896 species of lowland tropical rain forest tree in Yasuni National Park in Amazonian Ecuador. Of those species that were observed in the field, EFNs were found on 96 species (11.2%), widely distributed among different angiosperm families. This rate of incidence is high but consistent with other locations in tropical regions. Furthermore, this study adds 13 new genera and 2 new families (Urticaceae and Caricaceae) to the list of trees exhibiting EFNs. Using demographic data from a long-term forest dynamics plot, I compared the growth and survival rates of species that have nectaries with those that do not. This same process was also done with EFN incidence previously recorded at two different locations, Barro Colorado Island, Panama and Pasoh Forest Reserve, Malaysia. Results show that while species with EFNs have generally higher diameter growth rates, they also have higher mortality rates than species without, suggesting a cost to this ecological strategy.URO Summer Research FellowshipNo embarg

Recent X-ray observations of intermediate BL Lac objects

We present recent ROSAT, ASCA and SAX observations of intermediate BL Lac objects (IBLs), i.e. BL Lacs which are located between high-energy and low-energy peaked BL Lac objects with respect to alpha_rx. Both the statistical properties of IBLs from the RGB sample and a detailed broad band X-ray spectral analysis of two objects (1424+2401, 1055+5644) point towards a continuous distribution of synchrotron emission peak frequencies among BL Lac objects.Comment: 4 pages, 4 figures; to appear in the proceedings of the conference "BL Lac Phenomenon" held in Turku, Finland, June 22-26, 199

Bayesian Calibration - What, Why And How

Calibration of building energy models is important to ensure accurate modeling of existing buildings. Typically this calibration is done manually by modeling experts, which can be both expensive and time consuming. Â Additionally, biases of the individual modelers will creep into the process. Â Many methods of automated calibration have been developed which reduce costs, time and biases, including optimization using genetic or swarming algorithms, machine learning methods, and Bayesian methods. Â Bayesian methods differ significantly from the other optimization and machine learning methods in that inputs are assumed to be uncertain and main goal is not to match the prediction to the measured data as closely as possible, but to reduce the uncertainty in the inputs in a manner consistent with the measured data. Â Bayesian methods are particularly useful when there are model inputs that have high sensitivity and high uncertainty and where there is limited measured data to use for calibration. In this paper, the basic concepts of Bayesian calibration are explained and a typical application and results are demonstrated

Earlier Caribbean English and Creole in Writing

In research on Creoles, historical written texts have in recent decades been fruitfully employed to shed light on the diachronic development of these languages and the nature of Creole genesis. They have so far been much less frequently used to derive social information about these communities and to improve our understanding of the sociolinguistics and stylistic structure of these languages. This paper surveys linguistic research on early written texts in the anglophone Caribbean and takes a critical look at the theories and methods employed to study these texts. It emphases the sociolinguistic value of the texts and provides some exemplary analyses of early Creole documents

Collection of medium-resolution gamma spectra of certified Pu reference materials

A collection of medium resolution gamma-ray spectra from well-characterized Pu certified reference materials has been recorded using LaBr3(Ce) (2.0” x 0.5”) and CZT (500 mm3) detectors. Aiming to acquire the highest quality reference data, the spectra were measured for long acquisition times, ensuring very good counting statistics across potentially useful spectral intervals - up to 1.4 MeV for the CZT and up to 2.8 MeV for the LaBr3(Ce) detector. The experimental setup assures that the measurement geometry is stable and reproducible, and that the spectra have minimum influence from background radiation and pile-up effects. The spectra are available at the international database of reference gamma-ray spectra, and they feed phase I of the Pu isotopic inter-comparison exercise jointly organized by the ESARDA NDA Working Group and IAEA.JRC.E.7-Nuclear Safeguards and Forensic