251 research outputs found
Effect of green manure crops and organic amendments on incidence of nematode-borne tobacco rattle virus
Tobacco rattle tobravirus (TRV) may infect several ornamental bulb crops and is transmitted by trichodorid nematodes. Paratrichodorus teres, P. pachydermus and Trichodorus similis are the main vectors in the Netherlands. In field experiments the effects of various pre-crops and organic amendments on the TRV Infection Potential of Soils (TRV-IPS) and on disease level in tulip and gladiolus were studied. Organic matter amendment of soil at a rate of 1% dry weight has been shown to reduce the host finding activity of P. teres under laboratory conditions. In a field containing viruliferous P. teres dahlia, italian ryegrass, white mustard and fodder radish were grown or the soil was kept fallow and the resulting TRV-IPS prior to the bulbous test crops was measured by a soil dilution bait test method. The application of organic matter was tested after dahlia as pre-crop. Household waste compost (GFT compost) was applied as a soil mix or planting furrow treatment at 12 tons dry weight per ha for tulip and gladiolus. Spent mushroom compost (Champost) was added as planting furrow treatment at 17 or 12 tons dw/ha, respectively, for tulip and gladiolus. The percentage of TRV diseased plants was determined at flowering in all pre-crop and organic amendment treatments. Champost in the planting furrow and fodder radish as a preceding crop reduced the percentage infection in tulip under favourable conditions for TRV infection. In gladiolus most organic amendments, fodder radish as pre-crop and keeping the soil fallow reduced the TRV infection rate of the plants during the first growing season, but not of the plants grown from the corms in the next year
Self-esteem in patients with rheumatic diseases:The role of body-self unity
Background: Maintaining positive self-esteem is one of the challenges for patients with chronic diseases. Limitations in physical functioning, often associated with having a rheumatic disease, can influence the perception of the body as belonging to the person (or as detached from the self) and might thereby finally affect the self-esteem of patients. The concept of body-self unity has been investigated in a phenomenological research tradition that works with qualitative methodology and small samples. Objectives: To develop a questionnaire to measure body-self unity quantitatively and to investigate the predictive value of body-self unity for self-esteem in patients with rheumatic diseases. Methods: The Body Experience Questionnaire was developed for the measurement of body-self unity. Besides this questionnaire, illness cognitions, pain intensity, functional limitations and self-esteem were measured via computers with touchscreen. 168 patients (mean age = 54,2 years, 62% female) with a rheumatic disease participated in this study consecutive visiting the rheumatology clinic. To analyse predictors of self-esteem, hierarchical regression analyses were employed (first step demographic characteristics, second step disease related variables (disease duration, functional limitations, pain), final step psychological constructs (body-self unity, illness cognitions)). Results: The Body Experience Questionnaire revealed a two factor structure with good reliability (subscale harmony, Cronbachs alpha=.76; subscale alienation, Cronbachs alpha = 0.84). The final model of the hierarchical regression analyses showed that self-esteem can be predicted by helplessness, acceptance, harmony of body and self and most strongly by the alienation of body and self. R2 of the final model was 0.50 (delta R for psychological variables in the final step was 0.28). The relation between functional limitations and self-esteem was fully mediated by the psychological constructs body self unity and illness cognitions. Conclusion: This study showed the importance of psychological characteristics and particularly the experience of the body for self-esteem in patients with a rheumatic disease. Further research should explore therapies to increase the body-self unity
Salivary antibody responses to 10-valent pneumococcal conjugate vaccination following two different immunization schedules in a healthy birth cohort
Advances in silicon phased-array receiver IC's
Phased-Arrays are increasingly used, and require Silicon implementations to result in affordable multi-beam systems. In this paper, CMOS implementations of two novel analogue beamforming multi-channel receivers will be presented. A narrow-band highly linear system exploiting switches and capacitors in advanced CMOS is presented, implementing a fully passive switched capacitor vector modulator exploiting a zero-IF I/Q mixer: This technique is not applicable to very wideband phased-array receivers. These systems require true-time delay beamforming, which is implemented in the second CMOS implementation. An innovative gm-RC implementation of a true-time delay cell is exploited in a four-channel beamforming receiver with more than L.5 GHz bandwidth, in a standard 0.13 um CMOS process. Professional phased-arrays can often not live with the dynamic range limitations imposed by these implementations. To that end a SiGe implementation of an integrated receiver was realized targeting a digital beamforming phased-array. Dynamic range and flexibility of use were the main driving factors. Alltogether, these results show large progress with respect to the feasibility of Silicon-based phased-array front-end implementation for commercial as well as professional phased-arrays. © 2012 IEEE
Do the Unidentified EGRET Sources Trace Annihilating Dark Matter in the Local Group?
In a cold dark matter (CDM) framework of structure formation, the dark matter
haloes around galaxies assemble through successive mergers with smaller haloes.
This merging process is not completely efficient, and hundreds of surviving
halo cores, or {\it subhaloes}, are expected to remain in orbit within the halo
of a galaxy like the Milky Way. While the dozen visible satellites of the Milky
Way may trace some of these subhaloes, the majority are currently undetected. A
large number of high-velocity clouds (HVCs) of neutral hydrogen {\it are}
observed around the Milky Way, and it is plausible that some of the HVCs may
trace subhaloes undetected in the optical. Confirming the existence of
concentrations of dark matter associated with even a few of the HVCs would
represent a dramatic step forward in our attempts to understand the nature of
dark matter. Supersymmetric (SUSY) extensions of the Standard Model of particle
physics currently suggest neutralinos as a natural well-motivated candidate for
the non-baryonic dark matter of the universe. If this is indeed the case, then
it may be possible to detect dark matter indirectly as it annihilates into
neutrinos, photons or positrons. In particular, the centres of subhaloes might
show up as point sources in gamma-ray observations. In this work we consider
the possibility that some of the unidentified EGRET -ray sources trace
annihilating neutralino dark matter in the dark substructure of the Local
Group. We compare the observed positions and fluxes of both the unidentified
EGRET sources and the HVCs with the positions and fluxes predicted by a model
of halo substructure, to determine to what extent any of these three
populations could be associated.Comment: 12 Pages, 4 figures, to appear in a special issue of ApSS. Presented
at "The Multiwavelength Approach to Unidentified Gamma-Ray Sources" (Hong
Kong, June 1 - 4, 2004; Conference organizers: K.S. Cheng and G.E. Romero
Intraoperative search for neuroblastoma by MIBG and radioguided surgery with the gamma detector
The high-velocity clouds and the Magellanic Clouds
From an analysis of the sky and velocity distributions of the high-velocity
clouds (HVCs) we show that the majority of the HVCs has a common origin. We
conclude that the HVCs surround the Galaxy, forming a metacloud of 300 kpc in
size and with a mass of 3 10^9 M_sun, and that they are the product of a
powerful ``superwind'' (about 10^58 ergs), which occurred in the Magellanic
Clouds about 570 Myr ago as a consequence of the interaction of the Large and
Small Magellanic Clouds. The HVCs might be magnetic bubbles of semi-ionized
gas, blown from the Magellanic Clouds around 570 Myr ago, that circulate
largely through the halo of the Galaxy as a stream or flow of gas.Comment: 28 pages with 23 figure
A peculiar HI cloud near the distant globular cluster Pal 4
We present 21-cm observations of four Galactic globular clusters, as part of
the on-going GALFA-HI Survey at Arecibo. We discovered a peculiar HI cloud in
the vicinity of the distant (109 kpc) cluster Pal 4, and discuss its properties
and likelihood of association with the cluster. We conclude that an association
of the HI cloud and Pal 4 is possible, but that a chance coincidence between
Pal 4 and a nearby compact high-velocity cloud cannot be ruled out altogether.
New, more stringent upper limits were derived for the other three clusters: M
3, NGC 5466, and Pal 13. We briefly discuss the fate of globular cluster gas
and the interaction of compact clouds with the Galactic Halo gas.Comment: Accepted for publication in MNRA
HI clouds in the proximity of M33
Neutral hydrogen clouds are found in the Milky Way and Andromeda halo both as
large complexes and smaller isolated clouds. Here we present a search for Hi
clouds in the halo of M33, the third spiral galaxy of the Local Group. We have
used two complementary data sets: a 3^o x 3^o map of the area provided by the
Arecibo Legacy Fast ALFA (ALFALFA) survey and deeper pointed observations
carried out with the Arecibo telescope in two fields that permit sampling of
the north eastern and south-western edges of the HI disc. The total amount of
Hi around M33 detected by our survey is M. At least 50%
of this mass is made of HI clouds that are related both in space and velocity
to the galaxy. We discuss several scenarios for the origin of these clouds
focusing on the two most interesting ones: dark-matter dominated gaseous
satellites, debris from filaments flowing into M33 from the intergalactic
medium or generated by a previous interaction with M31. Both scenarios seem to
fit with the observed cloud properties. Some structures are found at anomalous
velocities, particularly an extended HI complex previously detected by Thilker
et al. (2002). Even though the ALFALFA observations seem to indicate that this
cloud is possibly connected to M33 by a faint gas bridge, we cannot firmly
establish its extragalactic nature or its relation to M33. Taking into account
that the clouds associated with M33 are likely to be highly ionised by the
extragalactic UV radiation, we predict that the total gas mass associated with
them is > 5 x 10^7 M. If the gas is steadily falling towards the M33
disc it can provide the fuel needed to sustain a current star formation rate of
0.5 M yr.Comment: 16 pages, 19 figures. Accepted for publication in A&
Intrapericardial Extralobar Pulmonary Sequestration Presenting as a Prenatal Intrathoracic Mass
An intrathoracic mass, which persisted during the remaining pregnancy, was first seen during routine ultrasound examination performed at 20 weeks gestation. After birth, the child was asymptomatic. Echocardiography showed the mass to be located intrapericardially. The mass was electively resected via sternotomy 3 weeks after the birth. Microscopic examination showed normal lung tissue surrounded by pleura corresponding to the diagnosis of extralobar pulmonary sequestration. To the authorsâ knowledge, this is the earliest described detection of such a lesion. Furthermore, this article reports the unique finding of a feeding vessel from the right pulmonary artery
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