Developmental Rate and Longevity of \u3ci\u3eIllinoia Pepperi\u3c/i\u3e (Homoptera: Aphididae) on Excised Blueberry Leaf Disks

The aphid Illinoia pepperi is the vector of blueberry shoestring virus, a serious disease of cultivated high bush blueberry. We present a laboratory study of the developmental rate of I. pepperi on excised blueberry leaf discs at different temperatures from 5 to 29°C. Growth rates were lowest at the upper temperature treatments (26 and 29°) and at 10°C. Growth rate and duration in degree-days for each life stage are presented as well as an overall regression equation for development. The lower developmental threshold was calculated at 3.4°C. The results are being used in a phenological management system and an epidemiological model for predicting spread of blueberry shoestring virus

Achievement rank affects performance and major choices in college

In this paper we study how a student's ordinal rank in a peer group affects performance and specialisation choices in university. By exploiting data with repeated random assignment of students to teaching sections, we find that a higher rank increases performance and the probability of choosing related follow-up courses and majors. We document two types of dynamic effect. First, earlier ranks are less important than later ranks. Second, responses to rank changes are asymmetric: improvements in rank raise performance, while decreases in rank have no effect. Rank effects partially operate through students’ expectations about future grades

Unintended reward costs: The effectiveness of customer referral reward programs for innovative products and services

To encourage customers’ referral behavior and expand their customer base, providers of innovative products and services often use customer referral reward programs (CRPs), though not all CRPs deliver on their initial promise. With one field experiment and four online experiments, this research investigates the effectiveness of rewarded referrals for recruiting new customers for more innovative (versus less innovative) offerings and outlines the conditions in which public referral rewards have unintended ramifications and decrease customers’ referral likelihood. In addition to establishing these effects for more innovative offerings, this research identifies some moderating consequences, such that the detrimental effect of referral rewards on referral behavior can be attenuated by not disclosing referral rewards (for recommenders) to referral recipients, increasing the referral reward size, and rewarding both recommenders and referral recipients. These findings have theoretical and managerial implications

Chandra Observation of an X-ray Flare at Saturn: Evidence for Direct Solar Control on Saturn's Disk X-ray Emissions

Saturn was observed by Chandra ACIS-S on 20 and 26-27 January 2004 for one full Saturn rotation (10.7 hr) at each epoch. We report here the first observation of an X-ray flare from Saturn's non-auroral (low-latitude) disk, which is seen in direct response to an M6-class flare emanating from a sunspot that was clearly visible from both Saturn and Earth. Saturn's disk X-ray emissions are found to be variable on time scales of hours to weeks to months, and correlated with solar F10.7 cm flux. Unlike Jupiter, X-rays from Saturn's polar (auroral) region have characteristics similar to those from its disk. This report, combined with earlier studies, establishes that disk X-ray emissions of the giant planets Saturn and Jupiter are directly regulated by processes happening on the Sun. We suggest that these emissions could be monitored to study X-ray flaring from solar active regions when they are on the far side and not visible to Near-Earth space weather satellites.Comment: Total 12 pages including 4 figure

Investigation of the porosity of ceramic composite materials based on hydroxyapatite and biodegradable polyesters

In the present study, we obtained porous composite materials based on biodegradable polymers and hydroxyapatite (HA) ceramics with different mass ratio of components. Special properties of porous materials allow to solve the most complicated problems in the field of bone tissue engineering. The characteristics of micro- and mesoporosity were investigated using low-temperature nitrogen adsorption. An experiment on the formation of a calcium-phosphate layer on the surface of samples in a SBF-solution was performed. The surface morphology of the composites throughout the experiment was investigated by SEM

Entoptic image quality of the retinal vasculature

AbstractSpatial details of entoptically visible retinal vessels were investigated using transcleral and Maxwellian-view stimulators. Nine normal subjects provided detailed drawings of the entoptic images which were digitized and superimposed onto digitized fundus photographs and fluorescein angiograms from the same eyes. Subjects also used a tracing method to locate visible entoptic features. The trans-scleral method provided images similar in detail to standard fundus photography (lacking capillary detail, but capturing larger arteries, veins, arterioles and venules) in the macula and around the disk. The Maxwellian-view method illuminated the fovea (7.7 degree field) and provided foveola capillary detail (capillaries traversing the foveola, the capillary arcade forming the FAZ) as well as the larger foveal vessels supplying the foveola, and often contained more foveal detail that available with fluorescein angiography

Численное решение уравнений Гинзбурга-Ландау для сверхпроводящего куба

Background/aim: The loss of short wavelength sensitive (SWS) cone mechanism sensitivity is related to severe vision loss in patients with age related maculopathy (ARM). A case-control study of patients with ARM and age matched controls was performed, using blue on yellow static perimetry. Methods: A bright yellow background at 594 nm isolated the responses of short wavelength cone mechanisms to 458 nm targets. A scanning laser ophthalmoscope produced stimuli and provided real time, simultaneous fundus illumination. The macula was probed with 16 Goldmann IV targets, 1–10 degrees from fixation, using a staircase method. Results: 24 patients with non-exudative ARM were matched to 24 subjects with normal fundus appearance. SWS cone pathway sensitivity for macular targets was significantly reduced in the patients with ARM compared to normals—15.45 (SD 4.56) dB v 17.22 (0.28) dB, respectively (p<0.0005). There was not only a diffuse loss of sensitivity in ARM patients, but also a localised loss of sensitivity over drusen (p<0.025). Neither the mean age, 69 (8) years, nor the mean visual acuity differed between groups, logMAR 0.09 (0.10) v 0.05 (0.06) for ARM patients v normals, respectively. Patients with soft drusen had lower sensitivity than those with hard drusen (p <0.05). Conclusion: A loss of SWS cone pathway sensitivity occurred in most patients with early ARM, despite good visual acuity, demonstrating a loss of visual function that cannot be attributed to ageing changes. The loss of sensitivity, despite good visual acuity, included both a diffuse loss and localised losses