Plant parasitic nematodes and their management in the Maritime provinces of Canada

Cet article présente une revue des nematodes phytoparasites qui causent des problèmes au Nouveau-Brunswick, en Nouvelle-Ecosse et à l'île-du Prince-Édouard, ainsi que les approches de lutte utilisées. Le nématode des lésions des racines (Pratylenchus penetrans) est la seule espèce de nématode de la région qui provoque régulièrement des baisses de rendement. Le nématode des nodosités des racines (Meloidogyne hapla) cause occasionnellement des dommages aux carottes (Daucus carota) mais les niveaux de population de ce nématode sont généralement très faibles. Le nématode du kyste du trèfle (Heterodera trifolii) est répandu mais il n'a pas causé de dommages aux récoltes de la région. Les techniques de production utilisées afin de réduire l'impact des nematodes phytoparasites dans les Maritimes, à savoir la rotation des cultures, les traitements nématicides, le renforcement des règlements de quarantaine et les pratiques de labourage, sont discutées. Un service-conseil sur les nematodes est également considéré.This paper presents a review of the plant parasitic nematodes that are of concern in New Brunswick, Nova Scotia, and Prince-Edward-Island, and the approaches used to manage them. The root lesion nematode (Pratylenchus penetrans) is the only nematode species in the region that regularly reduces crop yields. The northern root-knot nematode (Meloidogyne hapla) occasionally causes damage to carrots (Daucus carota), but population levels of this nematode species usually are very low. The clover cyst nematode (Heterodera trifolii) is widespread, but has not caused any damage to crops in the region. Management procedures used to reduce the impact of plant parasitic nematodes in the Maritime provinces, e.g. crop rotations, nematicide treatments, enforcement of quarantine regulations, and tillage practices are discussed. A nematode advisory service is also considered

Range analysis and terrain preference of adult southern white rhinoceros (Ceratotherium simum) in a South African private game reserve: Insights into carrying capacity and future management

The Southern white rhinoceros (Ceratotherium simum) is a threatened species, central to the tourism appeal of private game reserves in South Africa. Privately owned reserves in South Africa tend to be smaller than government run reserves such as Kruger National Park. Because of their relatively small size and the often heterogeneous nature of the landscape private game reserve managers benefit from detailed knowledge of white rhinoceros terrain selection preferences, which can be assessed from their ranging behaviours. We collected adult and sub-adult white rhinoceros distribution data over a 15 month period, calculating individual range size using kernel density estimation analysis within a GIS. From this, terrain selectivity was calculated using 50% and 95% kernels to extract terrain composition values. Jacob’s correction of the Ivlev’s selectivity index was subsequently applied to the terrain composition of each individual to identify trends in selectivity. Results reveal that adult males hold exclusive territories considerably smaller than those found in previous work conducted in “open” or large reserves. Similarly, results for the size of male versus female territories were also not in keeping with those from previous field studies, with males, rather than females, having the larger territory requirement. Terrain selection for both genders and age classes (adult and sub-adult) showed a strong preference for open grassland and avoidance of hill slope and riparian terrains. This research reveals white rhinoceros terrain selection preferences and how they influence range requirements in small, closed reserves. We conclude that this knowledge will be valuable in future white rhinoceros conservation management in small private game reserves, particularly in decisions surrounding removal of surplus individuals or augmentation of existing populations, calculation of reserve carrying capacity and future private reserve acquisition

Rosie: remote work system for decontamination and dismantlement

The Rosie worksystem includes a locomotor, heavy manipulator,operator console, and control system for remote operations. The locomotor is a highly mobile platform with tether management and hydraulic power onboard. The heavy manipulator is a high-payload, long-reach boom used to deploy a wide variety of tools and/or sensors into the work area. Rosie`s advanced control system, broad work capabibilites, and hardening/reliability for hazardous duty make it a new and unique capability that facilitates completion of significant cleanup projects throughout DOE and the private sector. Endurance testing of Rosie during last year has proven its capabilities and appropriateness for D&D applications. Design enhancements are being implemented to improve and add features necessary for deployment at an upcoming DOE facility decommissioning. A second Rosie unit is being fabricated fro use in the decommissioning of ANL`s CP-5 reactor facility starting late 1996. This paper overviews the Rosie system, testing results, design enhancements, and plans for use of this technology at CP-5

Information Presentation

The goal of the Information Presentation Directed Research Project (DRP) is to address design questions related to the presentation of information to the crew. The major areas of work, or subtasks, within this DRP are: 1) Displays, 2) Controls, 3) Electronic Procedures and Fault Management, and 4) Human Performance Modeling. This DRP is a collaborative effort between researchers at Johnson Space Center and Ames Research Center

Thermodynamics and kinetics of boundary friction

A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting is described consistently. Dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces are analyzed. Within the framework of a simple tribological model the stick-slip mode of friction, when the lubricant periodically melts and solidifies, is described. The obtained results are qualitatively compared with the experimental data.Comment: 14 pages, 6 figures, 33 reference

Requirement for the cell division protein DivIB in polar cell division and engulfment during sporulation in Bacillus subtilis

During spore formation in Bacillus subtilis, cell division occurs at the cell pole and is believed to require essentially the same division machinery as vegetative division. Intriguingly, although the cell division protein DivIB is not required for vegetative division at low temperatures, it is essential for efficient sporulation under these conditions. We show here that at low temperatures in the absence of DivIB, formation of the polar septum during sporulation is delayed and less efficient. Furthermore, the polar septa that are complete are abnormally thick, containing more peptidoglycan than a normal polar septum. These results show that DivIB is specifically required for the efficient and correct formation of a polar septum. This suggests that DivIB is required for the modification of sporulation septal peptidoglycan, raising the possibility that DivIB either regulates hydrolysis of polar septal peptidoglycan or is a hydrolase itself. We also show that, despite the significant number of completed polar septa that form in this mutant, it is unable to undergo engulfment. Instead, hydrolysis of the peptidoglycan within the polar septum, which occurs during the early stages of engulfment, is incomplete, producing a similar phenotype to that of mutants defective in the production of sporulation-specific septal peptidoglycan hydrolases. We propose a role for DivIB in sporulation-specific peptidoglycan remodelling or its regulation during polar septation and engulfment. <br /

Four-point Green functions in the Schwinger Model

The evaluation of the 4-point Green functions in the 1+1 Schwinger model is presented both in momentum and coordinate space representations. The crucial role in our calculations play two Ward identities: i) the standard one, and ii) the chiral one. We demonstrate how the infinite set of Dyson-Schwinger equations is simplified, and is so reduced, that a given n-point Green function is expressed only through itself and lower ones. For the 4-point Green function, with two bosonic and two fermionic external `legs', a compact solution is given both in momentum and coordinate space representations. For the 4-fermion Green function a selfconsistent equation is written down in the momentum representation and a concrete solution is given in the coordinate space. This exact solution is further analyzed and we show that it contains a pole corresponding to the Schwinger boson. All detailed considerations given for various 4-point Green functions are easily generizable to higher functions.Comment: In Revtex, 12 pages + 2 PostScript figure

Consumption of obesogenic foods in non-Hispanic black mother–infant dyads

Obesity continues to be a problem in the United States. Of particular concern is the epidemic of early childhood obesity. A significant predictor of child diet is maternal diet, but little is known about this relationship during infancy. This study examined the association between maternal and infant consumption of key food groups from 6 to 18 months using data from the Infant Care, Feeding, and Risk of Obesity Study, a prospective cohort of 217 non-Hispanic black, low-income, first-time mothers. Using data from 24-hr dietary recalls collected during in-home visits at 6, 9, 12, and 18 months, we assessed longitudinal associations between mother and child intake of both energy-dense, nutrient-poor (obesogenic) food groups and fibre-, nutrient-rich food groups using random intercept logistic regression. Both mothers and their infants had high intake of sugar-sweetened beverages, desserts, and sweets and low intake of vegetables and whole grains. Infant consumption of key food groups was strongly associated with maternal consumption, suggesting the need for focused interventions to target maternal diet as a pathway to decreasing risk for the establishment of poor dietary patterns early in life

Consumption of key food groups during the postpartum period in low-income, non-Hispanic black mothers

The postpartum period can impact diet quality and subsequently place women at greater risk for overweight or obesity. This study examined consumption of key food groups during the first 2 years postpartum among low income, non-Hispanic black, first-time mothers. Data were from the Infant Care, Feeding and Risk of Obesity Study, a cohort of 217 mother–infant dyads, followed from 3 to 18 months postpartum, collected from 2003 to 2007. At each study visit (3, 6, 9, 12, and 18 months) 24-h dietary recalls were collected. Consumption levels were compared to those recommended from the 2010 Dietary Guidelines for Americans (DGAs) for each of the following food groups: fruits, vegetables, grains, whole grains, protein foods and dairy, as well as an estimated upper limit for sugar-sweetened beverage (SSB) consumption. At each time point, mothers met recommended intake levels for grains and protein foods only. In random-intercept logistic regression models, no demographic or household characteristics were associated with a likelihood of consuming recommended levels for any of the food groups according to the DGAs. Given the low intake of fruits, vegetables, whole grains and lean protein foods and high intake of SSBs and refined grains, interventions targeting women's diet during the postpartum period are warranted