澳洲西花蓟马及番茄病毒性萎蔫病

西花蓟马（Franklienella occidentalis）是传播番茄、马铃薯、芦笋及辣椒病毒性萎蔫病的最主要的害虫之一。西花蓟马喜食辣椒、黄瓜和豆类作物的果实。其嚼食叶片和果实后,留下疤痕或使其畸形,尤其是幼苗和鲜嫩的组织更容易受其侵害。     

Assessing the reliability of ordered categorical scales using kappa-type statistics

Methods for the analysis of reliability of ordered categorical scales are discussed, focussing on the limitation of the single summary-weighted kappa coefficients. A symmetric matrix of kappa-type coefficients is suggested as an alternative. The method is proposed as being suitable for ordinal scale where there is no underlying continuum. Their application is illustrated using two data sets from reliability studies. If, instead, distances between categories can be specified, a weighted mean of the matrix terms can be used as a summary measure. This is equal to a weighted kappa coefficient with squared weights, provided distances between adjacent categories are equal. When a study design corresponds to a one-way random effects model, estimates of precision of kappa-type coefficient, including the coefficients described here, can be obtained using the delta-method, bootstrap resampling by subjects or jack-knifing by subjects. In the case of interobserver reliability studies, where there may be systematic differences between observers, the investigator may wish to generalise to a population of observers and subjects. In this case, jack-knifing by observer and subject is suggested. Empirical comparisons are made between standard error estimates based on the delta-method, on jack-knifing by subjects and a two-way jack-knife by subjects and observers. The results suggest that standard errors based on the delta-method or jack-knifing by subject alone may be overly precise.     

A section press and low elemental support for enhanced preparation of freeze-dried cryosections

A press- and specimen holder system is described, whereby thin, freeze-dried cryosections can be obtained more conveniently and with greater protection against contamination and harmful temperature fluctuations. The use of a grid and retainer assembly as the basic working unit, greatly facilitates low temperature work particularly when delicate grids are preferable from an analytical point of view. A new press has been constructed in order to keep the sections permanently pressed during freeze-drying and rewarming. The press also protects the sections during transfer to an external freeze-dryer.     

Sequelae of cesarean and vaginal deliveries: Psychosocial outcomes for mothers and infants.

Mother-infant dyads grouped according to whether the infants had been delivered vaginally (n?=?74) or by planned (n?=?37) or unplanned cesarean (n?=?56) were compared on psychosocial outcomes at 4 and 12 months postpartum. Hypotheses were that unplanned cesarean delivery would be related to less optimal outcomes and that this relationship would be mediated by mother's appraisal of the delivery and would attenuate over time. No delivery-related differences in mother–infant interactions were found at 4 or 12 months postpartum with one exception: Women low in neuroticism who delivered by unplanned cesarean showed less positive affect toward their infants at 4 months than did women high in neuroticism who delivered by unplanned cesarean or women in any other group. There was some evidence of the mediating role of maternal appraisal of the delivery on these effects. In general, the results indicate little cause for concern about the quality of mother–infant interactions following cesarean deliveries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chronic CO poisoning. Use of generator gas during the second world war and recent research

The consequences of long-lasting and low-grade exposure to carbon monoxide are a matter of debate. During the second world war, lack of petrol led to widespread use of wood as fuel (generator gas vehicles), especially in the Nordic countries. This caused many cases of "acute" or "chronic" carbon monoxide poisoning. Typical symptoms of "chronic poisoning" were headache, dizziness and tiredness. Usually the symptoms disappeared after some weeks or month, but in some patients probably became permanent. The experiences from the generator gas era are now almost forgotten, and chronic carbon monoxide poisoning is easily overlooked. The authors describe two cases of such poisoning. A crane driver at a smelting works developed permanent symptoms after twenty years of exposure. A faulty oil-fired central heating system caused long-lasting symptoms in four members of a family.     

Maternal employment and development of the father–infant relationship in the first year.

This study investigated links between maternal employment and fathers' parenting quality when their infants were 4 and 12 months old. Sixty-three fathers were videotaped interacting with their infants and completed questionnaires regarding their involvement in caregiving, parenting stress, and marital quality, and mothers reported on children's temperament. Fathers whose wives either did not work outside the home or worked part time were more sensitive and responsive to their children when they were more involved in caregiving; men whose wives worked full time exhibited more negative affect and behavior when they participated more in child care. Men whose wives were not employed also were more positive in their interactions when they were happier with their marriage, whereas men whose wives worked either part time or full time exhibited a negative relation between parenting behavior and marital quality. Maternal work circumstances were not related to fathers' parenting stress; rather, marital quality and child temperament predicted parenting stress at 4 and 12 months for all fathers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Requirement-based approach for groupware environments design

Groupware applications have special features that, if they were taken into account from the very beginning, could reasonably improve the quality of the system. Such features concern human-computer-human interactions, i.e. a further step in the human-computer interaction field: communication, collaboration, cooperation and coordination, time, space, and awareness are issues to be considered. This paper presents a novel approach to gather requirements for groupware applications. The proposal is based on a methodology that includes the use of templates to gather the information regarding the different types of requirements. The requirements templates have been extended to include new information to give account of specific features concerning groupware applications. The information gathered is managed in a CASE tool we have developed; then general and specific diagrams are automatic or semi-automatically generated.     

Improving location awareness in indoor spaces using RFID technology

Location awareness is a key issue to improve the development of autonomous entities that are embedded into ubiquitous computing environments. GPS seems to be the best solution to develop outdoor location systems, but the performance of these systems is not good enough to locate objects or humans within indoor environments, mainly if accuracy and precision are required. In this article we propose the use of a cheap and reliable technology as RFID to develop a passive RFID-based indoor location system that is able to accurately locate autonomous entities, such as robots and people, within a defined surface. This system is applied to solve the robot tracking problem. We include the evaluation of the proposal by comparing our system technology performance with other alternatives built on different technologies (Wi-Fi, Bluetooth, IrDA, ultrasound, etc.). We have also performed a location awareness proof concept test to analyze the viability of the approach.     

A domain specific language notation for a language learning activity generation tool

Multimedia Tools and Applications - Globalization has increased the need for society to master new languages. This need has encouraged the launch of many applications dedicated to language...     

Chemotaxis in shear flow: Similarity solutions of the steady-state chemoattractant and bacterial distributions

When chemotactic bacteria are exposed to a concentration gradient of chemoattractant while flowing along a channel, the bacteria accumulate at the interface between the chemoattractant source and bacterial suspension. Assuming that the interface is no-slip, we can apply the shear flow approximation near the no-slip boundary and solve a steady-state convection-diffusion model for both chemoattractant and bacterial concentrations. We suggest similarity solutions for the two-dimensional problem and identify a critical length scale η_c for bacteria chemotaxis in a given concentration gradient. The analysis identifies three dimensionless groups representing, respectively, chemotactic sensitivity, the chemotaxis receptor constant, and the bacteria diffusion coefficient, which typically show coupled effects in experimental systems. We study the effect of the dimensionless groups separately and provide understanding of the system involving shear flow and chemotaxis.