586 research outputs found
Search for gamma ray lines from SS433
Data obtained with the Gamma Ray Spectrometer (0.3 to 9 MeV) aboard the Solar Maximum Mission satellite from 1980 to 1985 for evidence of the reported Doppler shifted lines from SS433 were examined. The data base covers a total of 468 days when SS433 was in the field of view and includes times of quiescent and flaring radio activity. In 9 day integrations of the SMM data no evidence is found for gamma ray line emission from SS433. The 99% confidence upper limits for 9 day integrations of the shifted 1.37 and 6.1 MeV lines are 0.0013 gamma/sq cm-s and 0.0007 gamma/sq cm-s, respectively. The 360 day time averaged upper limits are 0.0002 gamma/sq cm-s x 0.0001 gamma/sq cm-s for both lines
Global Energetics of Thirty-Eight Large Solar Eruptive Events
We have evaluated the energetics of 38 solar eruptive events observed by a
variety of spacecraft instruments between February 2002 and December 2006, as
accurately as the observations allow. The measured energetic components
include: (1) the radiated energy in the GOES 1 - 8 A band; (2) the total energy
radiated from the soft X-ray (SXR) emitting plasma; (3) the peak energy in the
SXR-emitting plasma; (4) the bolometric radiated energy over the full duration
of the event; (5) the energy in flare-accelerated electrons above 20 keV and in
flare-accelerated ions above 1 MeV; (6) the kinetic and potential energies of
the coronal mass ejection (CME); (7) the energy in solar energetic particles
(SEPs) observed in interplanetary space; and (8) the amount of free
(nonpotential) magnetic energy estimated to be available in the pertinent
active region. Major conclusions include: (1) the energy radiated by the
SXR-emitting plasma exceeds, by about half an order of magnitude, the peak
energy content of the thermal plasma that produces this radiation; (2) the
energy content in flare-accelerated electrons and ions is sufficient to supply
the bolometric energy radiated across all wavelengths throughout the event; (3)
the energy contents of flare-accelerated electrons and ions are comparable; (4)
the energy in SEPs is typically a few percent of the CME kinetic energy
(measured in the rest frame of the solar wind); and (5) the available magnetic
energy is sufficient to power the CME, the flare-accelerated particles, and the
hot thermal plasma
TRANSMISSION OF VIBRATION ABOUT THE KNEE
The purpose of this study was to examine and describe effects of knee flexion angle, stance width and vibration platform frequency on the transmission of vertical acceleration about the knee. Fifteen adults were exposed to various vibration conditions while standing on a side-to-side vibration platform. Vertical acceleration data, expressed as transmission, were shown to be attenuated for all vibration conditions. A larger degree of knee flexion however, was conducive to greater attenuation about the knee. Such information may be used to develop vibration training programs with a more thorough understanding of effects of vibration
Gamma-ray lines and neutrons from solar flares
The energy spectrum of accelerated protons and nuclei at the site of a limb flare was derived by a technique, using observations of the time dependent flux of high energy neutrons at the Earth. This energy spectrum is very similar to the energy spectra of 7 disk flares for which the accelerated particle spectra was previously derived using observations of 4 to 7 MeV to 2.223 MeV fluence ratios. The implied spectra for all of these flares are too steep to produce any significant amount of radiation from pi meson decay. It is suggested that the observed 10 MeV gamma rays from the flare are bremsstrahlung of relativistic electrons
Diagnosticul modificărilor morfologice ale parenchimului renal în hidronefroză la copii prin puncţie-biopsie
Summary
The authors present the results of the morphologic study of kidney
parenchyma’s pathologic modifications in 16 children with hydronephrosis through puncture-biopsy (Bard Magnum Biopsy System).
In conclusion the puncture-biopsy method can be used to determine the disease clinical phase, as well as to reveal some pathogenetic mechanisms that allows by the aim of organ preservation the
surgical tactics optimization and postoperative treatment adjustment.
Introducere. Diagnosticul modificărilor morfologice în
parenchimul renal, în cadrul hidronefrozei la copii, se bazează
pe evaluarea leziunilor structurale care în mare măsură depind
de diversitatea factorilor etiologici.
Material şi metode. Studiul morfologic întreprins a avut
ca scop elucidarea modificărilor morfologice ale parenchimului
renal prin puncţie-biopsie efectuate cu Bard Magnum Biopsy
System. Au fost studiate bioptate ale parenchimului renal la 16
copii cu hidronefroză. Bioptatele au fost fixate în sol. Formol
neutru 4 şi 10%, incluse ulterior în parafină. Au fost utilizate
coloraţiile hematoxilină-eozină, van Ghieson, Congo red.
Rezultate şi concluzii. Examenul efectuat la microsocpia optică
a evidenţiat modificări variate în toate componentele nefronului şi
ale structurilor interstiţial-vasculare de intensitate şi de origine diversă: dilatativ-compresive - ectazie generalizată, leziuni
ischemico-sclerotice şi atrofico-deformative; obstructive - de tip
„hidronefroză intrarenală", transformare tubulară pseudochistică,
displazice - imaturitate şi mostruozităţi glomerulare, polimorfism
structural, oligoglomerulonefronie, multiglomerularitate;
inflamatorii - tubulo-interstiţiale, peri- şi intraglomerulare exudativalterative, polimorfocelulare şi infiltrativ sclerotice; stenoze
vasculare, hipertrofice şi sclerozante, depozite calcinoase
postischemice etc. Caracterul, gradul lezional şi complexitatea
morfologică a modificărilor în parenchimul renal pun în evidenţă
două variante histopatologice: varaianta complicată şi pe cea
necomplicată. Referitor la evoluţia modificărilor morfopatologice
în parenchimul renal, acesta suportă 2 faze succesive: faza de
ectazie şi faza de atrofie. De menţionat că prezenţa elementului
inflamator este determinantă în morfogeneza dereglărilor
funcţionale renale în cadrul variantei complicate.
Aşadar, diagnosticul prin puncţie-biopsie în hidronefroză
poate fi utilizat în aprecierea variantelor patologice şi a fazelor
clinico-evolutive, a studiului unor verigi etiopatogenetice ale
maladiei, ceea ce ar permite soluţionarea problemei în vederea
păstrării organului, precum şi determinarea conduitei în perioada
postoperatorie
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Orthographic facilitation in oral vocabulary acquisition
An experiment investigated whether exposure to orthography facilitates oral vocabulary learning. A total of 58 typically developing children aged 8-9 years were taught 12 nonwords. Children were trained to associate novel phonological forms with pictures of novel objects. Pictures were used as referents to represent novel word meanings. For half of the nonwords children were additionally exposed to orthography, although they were not alerted to its presence, nor were they instructed to use it. After this training phase a nonword-picture matching posttest was used to assess learning of nonword meaning, and a spelling posttest was used to assess learning of nonword orthography. Children showed robust learning for novel spelling patterns after incidental exposure to orthography. Further, we observed stronger learning for nonword-referent pairings trained with orthography. The degree of orthographic facilitation observed in posttests was related to children's reading levels, with more advanced readers showing more benefit from the presence of orthography
Pieloectazia la copii
Summary
The algorithm of diagnostics was produced on the basis of inspection 1241 children which allows to determine the reason and
level of obstruction of the urinary system.
Introducere . Pieloectazia provocată de dereglări
urodinamice ale tractului urinar, în prezent se întâlneşte frecvent
şi necesită un diagnostic diferenţial pentru aprecierea cauzei şi
a nivelului de obstrucţie.
Material şi metodă. Studiul a fost efectuat în baza evaluării
a 1241 copii cu pieloectazie pe parcursul anilor 2000-2005. Sau analizat datele examinării clinico-paraclinice: examen clinic,
ecografie, sonografie diuretică, urografie excretorie,
cistouretrografie micţională, scintigrafie, inclusiv diuretică,
raport calice-parenchim, cistometrie, cistografie, etc.
Rezulate şi discuţii. De obicei, copiii se internează cu
diagnosticul „Pieloectazie. Hidronefroză”, depistate ecografic,
iar în faţa urologului apar mai multe întrebări:
- este o dilatarea a cavităţilor renale sau diverse chisturi renale;
- ce a provocat pieloectazia: obstrucţia tractului urinar,
refluxul vezico-renal (RVR), diabetul insipid, etc.;
- dacă este obstrucţie - la ce nivel (joncţiunea pielo-ureterală,
vezico-uretrală, uretră sau vezica neurogenă);
- în caz de obstrucţia joncţiunii pielo-ureterale - e funcţională sau
organică, e necesar şi când trebuie aplicat tratamentul chirurgical.
Am elaborat un algoritm de diagnostic diferenţial al
pieloectaziei, în rezultatul implementării căruia, în lotul de 1241
copii - hidronefoza s-a depistat la 189, megaureterohidronefroza
obstructivă - la 143, RVR - la 464, vezica neurogenă - la 174
copii. În caz de obstrucţiajoncţiunii pielo-ureterale (OJPU), pentru
a diferenţia obstrucţia funcţională, am recurs la ecografie şi
scintigrafie diuretică pe vezica goală (sonda vezicală) exlusă
gravitaţia de cea organică. Din 189 copii cu OJPU, la 23 s-a
depistat obstrucţia funcţională cauzată de inmaturitatea JPU.
Pieloectazia la aceşti copii se menţine ani la rând, fără a progresa
şi fără a afecta funcţia renală. La 156 copii s-a depistat obstrucţia
organică care a necesitat intervenţie chirurgicală. La 22 pacienţi
cu hidronefroză avansată s-a efectuat nefrectomia. În perioada
pre- şi postoperatorie s-a apreciat raportul calice-parenchim.
Concluzii:
1. Pentru un diagnostic precoce al pieloectaziei este necesar
a efectua ecografia intrauterină, precum şi în primele 3 luni de
viaţă ale copilului.
2. Copiii cu pieloectazie necesită un examen riguros, cu
utilizarea mai multor metode diagnostice, ca: ecografia şi
scintigrafia diuretică, urografia, cistouretrografia, raportul caliceparenchim, etc.
3. În perioada pre- şi postoperatorie în OJPU, aprecierea
raportului calice-parenchim e un indice mai adecvat decât
raportul bazinet-parenchim, deoarece mărimea bazinetului
depinde de particularităţile anatomice şi de metodele de
tratament chirurgical aplicate
Observations of GRB 990123 by the Compton Gamma-Ray Observatory
GRB 990123 was the first burst from which simultaneous optical, X-ray and
gamma-ray emission was detected; its afterglow has been followed by an
extensive set of radio, optical and X-ray observations. We have studied the
gamma-ray burst itself as observed by the CGRO detectors. We find that
gamma-ray fluxes are not correlated with the simultaneous optical observations,
and the gamma-ray spectra cannot be extrapolated simply to the optical fluxes.
The burst is well fit by the standard four-parameter GRB function, with the
exception that excess emission compared to this function is observed below ~15
keV during some time intervals. The burst is characterized by the typical
hard-to-soft and hardness-intensity correlation spectral evolution patterns.
The energy of the peak of the nu f_nu spectrum, E_p, reaches an unusually high
value during the first intensity spike, 1470 +/- 110 keV, and then falls to
\~300 keV during the tail of the burst. The high-energy spectrum above ~MeV is
consistent with a power law with a photon index of about -3. By fluence, GRB
990123 is brighter than all but 0.4% of the GRBs observed with BATSE, clearly
placing it on the -3/2 power-law portion of the intensity distribution.
However, the redshift measured for the afterglow is inconsistent with the
Euclidean interpretation of the -3/2 power-law. Using the redshift value of >=
1.61 and assuming isotropic emission, the gamma-ray fluence exceeds 10E54 ergs.Comment: Submitted to The Astrophysical Journal. 16 pages including 4 figure
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