A
bstract
The cross section of the diffractive process
e
+
p
→
e
+
Xp
is measured at a centre-of-mass energy of 318 GeV, where the system
X
contains at least two jets and the leading final state ...proton
p
is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities
Q
2
<
2 GeV
2
and in deep-inelastic scattering with 4 GeV
2
< Q
2
<
80 GeV
2
. The results are compared to next- to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep-inelastic scattering.
Ewing's sarcoma (ES) of the skull is rare. Herein, we present 2 cases of ES that involved the cranium in young children. In one case, the lesion originated in the petrous temporal bone; in the other, ...the frontal bone. Both children were acutely compromised neurologically by signs and symptoms of raised intracranial pressure. In both cases, radiographs revealed massive tumors affecting the skull. Neurosurgical resection of the tumor was undertaken in both instances, and the diagnosis of ES was confirmed by immunohistochemistry, cytogenetic analysis (translocation 11;22), spectral karyotyping and RT-PCR (demonstration of a EWS/FLI1 fusion transcript). Following aggressive surgical resection, both children received intensive chemotherapy. No child has received radiation therapy. One child is alive and well 8 years after diagnosis without any evidence of residual disease. The other is currently undergoing chemotherapy for her tumor. The principles involved in the management of children with cranial-based ES are discussed. These 2 cases serve to illustrate the fact that even children with massive ES tumors of the cranium may be salvaged with aggressive combination therapy.
A series of 62 children with cerebral arteriovenous malformations admitted to our department in the course of 17 years (1975-1992) was reviewed in a retrospective study. In 54 cases hemorrhagic ...stroke was the first presenting symptom, followed by epilepsy in five cases. On admission 26 children presented with a neurological deficit, and 21 were admitted with a grade 3 status according to Botterell. Fifty-one malformations were supratentorial (41 hemispheric, 10 deep-seated) while 11 were infratentorial. According to Mori's criteria, 28 lesions were small, 19 medium, and 15 large. Fifty-two children were operated on, with total excision of the malformation achieved in 47 cases. In two children the malformation recurred. The evolution of neurological disorders has been studied with a mean follow-up of 8.5 years. Fifty patients had a satisfactory outcome on the Glasgow Outcome Scale. Four children died. These results were compared with those reported elsewhere in the pediatric literature.
This study analyzed a series of 83 patients operated on for foraminal lumbar disc herniation.
This study sought to develop clinical and radiologic diagnoses, evaluate interlaminar and extra-articular ...exposures, and evaluate postoperative results.
Some authors have reported a specific clinical syndrome, but other reports have indicated the clinical picture is indistinguishable from usual posterolateral disc herniation. Surgical management often has been compared between the interlaminar and extra-articular approaches.
Clinical findings were reviewed. All patients were evaluated with computed tomography, but radiologic diagnosis required computed tomographic discography for 26 patients. Interlaminar exposure with partial medial facetectomy was performed in 73 patients and an extra-articular approach was necessary in 10 patients. Postoperative results were evaluated with a 2-year follow-up.
Foraminal lumbar disc herniations have a specific clinical picture, particularly severe radicular signs. Precise preoperative radiologic evaluation is essential for successful operative procedure. Postoperative results were good in 76% of the patients. The other patients felt mild residual radicular pain, although no residual root compression was found on postoperative computed tomography. Only 21% of the patients that had a radicular deficit recovered totally.
Foraminal lumbar disc herniation involves characteristic clinical features. Radiologic diagnosis requires high-resolution computed tomography, computed tomographic discography, or magnetic resonance imaging. Most foraminal lumbar disc herniations are reached through the interlaminar exposure extended to the upper lamina and medial facet without total facetectomy. An extra-articular approach should be reserved for extra-foraminal herniations.
A
bstract
A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic
ep
scattering at HERA using data collected by the H1 experiment ...corresponding to an integrated luminosity of 290 pb
−1
. The investigated phase space is spanned by the photon virtuality in the range of 4
< Q
2
<
100 GeV
2
and by the fractional proton longitudinal momentum loss
x
ℙ
<
0
.
03. The resulting cross sections are compared with next-to-leading order QCD predictions based on diffractive parton distribution functions and the value of the strong coupling constant is extracted.
Pseudocyst formation is a rare complication of ventriculo-peritoneal shunt, occurring in only 22 cases of 1300 shunts from 1968 to 1992. The most common presentation is that of abdominal signs rather ...than neurological or infectious signs. The diagnosis is easy with ultrasonography. The difficulty is to evocate the cyst and to correlate symptoms and cyst. Treatment of the cyst was by aspiration (21 cases) and excision in 7 cases. The therapeutic choice is made according to the ultrasound findings. When the cyst was infected, an external ventricular shunt was used temporary, but this type of shunt must be avoided where possible. Three patients died.
The authors discuss the fabrication, performance, and design of a novel, planar In/sub 0.53/Ga/sub 0.47/ As/InP separate absorption and multiplication region avalanche photodiode (SAM-APD) with ...floating guard rings and a double Zn diffused junction. The APD, grown by both vapor phase epitaxy and metalorganic vapor phase epitaxy, is observed to have a uniform gain of 85, a minimum primary dark current density of 5*10/sup -6/ A/cm/sup 2/ at 90% of breakdown, and a capacitance of 0.4 pF for a front-side illuminated device. Both experimental and analytical results show that the double-diffused floating guard ring structure prevents edge breakdown, and also greatly reduces the electric field along the semiconductor/insulator surface. The operation mechanisms and the optimum design of the planar APD based on a two-dimensional device model are discussed.< >
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A first measurement is presented of exclusive photoproduction of ... mesons associated with leading neutrons at HERA. The ...data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of ... GeV and correspond to an integrated luminosity of 1.16 pb... The ... mesons with transverse momenta ... GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, ..., are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality ... GeV..., the total energy of the photon-proton system ... GeV and the polar angle of the leading neutron ... mrad. The cross section of the reaction ... is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ... meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, ..., is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction ...
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The properties of final modules of a high resolution lead/scintillating-fibre calorimeter to upgrade the backward region of the H1 detector were studied with electrons in the energy range from 2–60 ...GeV. The electromagnetic calorimeter consists of scintillating fibres with a diameter of 0.5 mm embedded in a lead matrix. This small fibre radius, in combination with a lead-to-fibre ratio of 2.27:1, ensures excellent energy resolution which has been measured to be
δ/E=7.1%/
E/GeV
⊕ 1.0%
. The spatial resolution as a function of energy for impact points at the center of a cell is given by
4.4 mm/
E/GeV
+ 1.0 mm
. The time resolution was found to be better than 0.4 ns.
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Available for:
IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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