250 research outputs found
A measurement of the isovector giant quadrupole resonance in lead-208 using elastic polarized photon scattering
No full textRestriction data tranferred 2014-07-01T11:12:23-05:00
Original Data
Group with Access UIUC Users [automated]
Release Date: none
Reason: ETDs are only available to UIUC Users without author permissionETDs are only available to UIUC Users without author permissionU of I OnlyThis experiment used highly polarized tagged photons to measure polarization asymmetries for elastic scattering in \sp{208}Pb in the energy region of the isovector giant quadrupole resonance (IVGQR). These measurements were performed at excitation energies between 16 and 30 MeV.Photons with enhanced linear polarization were obtained from an off-axis tagged photon beam by making a kinematic selection on the post-bremsstrahlung electrons. Scattered photons were detected in two large NaI(Tl) crystals.The polarization asymmetries clearly show the signature for interference between the isovector giant quadrupole resonance and the underlying electric dipole strength. The gross features of the IVGQR strength distribution were obtained in a relatively model independent manner. An isovector giant quadrupole resonance was observed at an excitation energy of 20.1 0.5 MeV, with a width of 6.3 0.5 MeV, and an energy weighted strength of 1.4 0.3 isovector sum rule units.Made available in DSpace on 2011-05-07T11:51:39Z (GMT). No. of bitstreams: 2
license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5)
9210778.pdf: 3565928 bytes, checksum: 40616aaea301ffaf113789a1d9bdf254 (MD5)
Previous issue date: 1991Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:33:30Z
Item is restricted indefinitely
Changes in body mass, appetite-related hormones, and appetite sensation in women during 4 days of hypobaric hypoxic exposure equivalent to 3,500-m altitude
No full text: Altitude exposure may suppress appetite and hence provide a viable weight-loss strategy. While changes in food intake and availability as well as physical activity may contribute to altered appetite at altitude, herein we aimed to investigate the isolated effects of hypobaric hypoxia on appetite regulation and sensation. Twelve healthy women (age: 24.0 ± 4.2 years, body mass: 60.6 ± 7.0 kg) completed two 4-day sojourns in a hypobaric chamber, one in normoxia [PB = 761 mmHg, 262 m (NX)] and one in hypobaric hypoxia [PB = 493 mmHg (HH)] equivalent to 3,500-m altitude. Energy intake was standardized 4 days prior and throughout both sojourns. Plasma concentrations of leptin, acylated ghrelin, cholecystokinin (CCK), and cytokine growth differentiation factor 15 (GDF15) were determined every morning. Before and after breakfast, lunch, and dinner, appetite was assessed using visual analog scales. Body mass was significantly decreased following HH but not NX (-0.71 ± 0.32 kg vs. -0.05 ± 0.54 kg, condition: P < 0.001). Compared to NX, acylated ghrelin decreased throughout the HH sojourn (condition × time: P = 0.020), while leptin was higher throughout the entire HH sojourn (condition: P < 0.001). No differences were observed in CCK and GDF15 between the sojourns. Feelings of satiety and fullness were higher (condition: P < 0.001 and P = 0.013, respectively), whereas prospective food consumption was lower in HH than in NX (condition: P < 0.001). Our findings suggest that hypoxia exerts an anorexigenic effect on appetite-regulating hormones, suppresses subjective appetite sensation, and can induce weight loss in young healthy women. Among the investigated hormones, acylated ghrelin and leptin most likely explain the observed HH-induced appetite suppression.NEW & NOTEWORTHY This study investigated the effects of hypoxia on appetite regulation in women while strictly controlling for diet, physical activity, menstrual cycle, and environmental conditions. In young women, 4 days of altitude exposure (3,500 m) decreases body weight and circulating acylated ghrelin levels while preserving leptin concentrations. In line with the hormonal changes, altitude exposure induces alterations in appetite sensation, consisting of a decreased feeling of hunger and prospective food intake and an increased feeling of fullness and satiety
Long-Term Effects of Prematurity on Resting Ventilatory Response to Hypercapnia.
No full textManferdelli, Giorgio, Benjamin J. Narang, Mathias Poussel, Damjan Osredkar, Grégoire P. Millet, and Tadej Debevec. Long-term effects of prematurity on resting ventilatory response to hypercapnia. High Alt Med Biol. 22:420-425, 2021. Background: This study investigated the resting ventilatory response to hypercapnia in prematurely born adults. Materials and Methods: Seventeen preterm and fourteen full-term adults were exposed to normoxic hypercapnia (two 5-minute periods at 3% and 6% carbon dioxide [CO 2 ] interspersed by 5-minute in normoxia). Pulmonary ventilation ([Formula: see text]) and end-tidal partial pressure of CO 2 (Petco 2 ) were measured continuously. Results: No difference in lung function was observed between preterm and full-term adults. Petco 2 was lower in preterm than in full-term adults (p 2 , both [Formula: see text] and Petco 2 increased in a similar way in preterm and full-term adults. However, at the end of the 6% CO 2 period, there was a significantly higher [Formula: see text] in preterm compared with full-term adults (30.2 ± 7.5 vs. 23.7 ± 4.5 L/min, p 2 (46.9 ± 2.1 vs. 50.6 ± 2.1 L/min, p = 0.99). Breath frequency was higher in preterm than in full-term adults (17.9 ± 4.0 vs. 12.8 ± 3.5 b/min, p 2 exposure. Conclusions: Although data suggest that prematurity results in resting hypocapnia, the exact underlying mechanisms remain to be elucidated. Moreover, preterm adults seem to have increased chemosensitivity to hypercapnia
An absolute measurement of the photodisintegration differential cross section of the deutron
No full textWe have measured the absolute 2H( 1 ,p )n angular distribution using the Illinois
LASA detector at the Saskatchewan Accelerator Laboratory's tagged photon facility.
Using 40 to 90 MeV photons, we aimed to measure the differential cross section with
a statistical precision of typically 5% in angular bins of 3° and energy bins of 2 MeV.
Although our measurement achieved this goal, the contribution of systematic errors
was larger than anticipated and thus compromised the utility of this result.
Without these systematic errors, this measurement (when combined with the
world data set) would have provided an extensive experimental data set with an
accuracy which was better than the scatter between the various theoretical calculations
for the interaction. Refinements to the treatment of the interaction would then
have been testable. In particular, because the shape of the angular distribution in this
energy regime is sensitive to meson exchange currents, it would have been possible to
investigate the methods for incorporating these currents into calculations.Submitted by Carolyn Mead ([email protected]) on 2011-04-20T19:06:43Z
No. of bitstreams: 1
1996_fox.pdf: 8797868 bytes, checksum: d6e74caf1667ab402f969b01d4c4b17c (MD5)Made available in DSpace on 2011-04-20T19:06:43Z (GMT). No. of bitstreams: 1
1996_fox.pdf: 8797868 bytes, checksum: d6e74caf1667ab402f969b01d4c4b17c (MD5)
Previous issue date: 1996Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead ([email protected]) on 2011-04-20T19:06:44Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:11:24-05:00
Original Data
Group with Access UIUC Users [automated]
Release Date: none
Reason: ThesisThesisU of I Onl
Measurement of the Reaction from 0.6 to 1.9 GeV/c
No full textThe pbar p -> Ks Ks -> 4pi+/- cross section was measured at incident antiproton momenta between 0.6 and 1.9 GeV/c using the CERN Low Energy Antiproton Ring (LEAR). This investigation was part of a systematic study of in-flight antiproton-proton annihilations into two-neutral-meson final states in a search for hadronic resonances. A coarse scan of the pbar p -> Ks Ks cross section as a function of center-of-mass energy between 1.964 and 2.395 GeV/c^2 and a fine scan of the region surrounding the Xi(2220) are presented. Upper limits on the product branching ratio BR(Xi -> pbar p)BR(Xi -> Ks Ks) are determined for a wide range of mass and width assumptions based on the non-observation of the Xi(2220). A rise in the pbar p -> Ks Ks cross section is observed near 2.15 GeV/c^2, which is consistent with the f2(2150) resonance.The pbar p -> Ks Ks -> 4pi+/- cross section was measured at incident antiproton momenta between 0.6 and 1.9 GeV/c using the CERN Low Energy Antiproton Ring (LEAR). This investigation was part of a systematic study of in-flight antiproton-proton annihilations into two-neutral-meson final states in a search for hadronic resonances. A coarse scan of the pbar p -> Ks Ks cross section as a function of center-of-mass energy between 1.964 and 2.395 GeV/c^2 and a fine scan of the region surrounding the Xi(2220) are presented. Upper limits on the product branching ratio BR(Xi -> pbar p)BR(Xi -> Ks Ks) are determined for a wide range of mass and width assumptions based on the non-observation of the Xi(2220). A rise in the pbar p -> Ks Ks cross section is observed near 2.15 GeV/c^2, which is consistent with the f2(2150) resonance
Search for narrow resonances in the reaction
No full textThe reaction pbar p -> pbar p pi+ pi- has been studied with high statistics at CERN-LEAR with incident pbar momenta from 1.65 to 2.0 GeV/c by the JETSET (PS202) experiment. The aim of this paper is to search for narrow resonances decaying to pbar p. No evidence for such structures is found. In particular, an upper limit for the production of a 2.02 GeV state with a width of Gamma = 20 MeV, having been seen in other hadroproduction experiments, is established. Our results restrict the cross section for such a peak to be below 200 nb at the 95% confidence level.The reaction pbar p -> pbar p pi+ pi- has been studied with high statistics at CERN-LEAR with incident pbar momenta from 1.65 to 2.0 GeV/c by the JETSET (PS202) experiment. The aim of this paper is to search for narrow resonances decaying to pbar p. No evidence for such structures is found. In particular, an upper limit for the production of a 2.02 GeV state with a width of Gamma = 20 MeV, having been seen in other hadroproduction experiments, is established. Our results restrict the cross section for such a peak to be below 200 nb at the 95% confidence level
Recommended from our members
Persistence of the C + O Si resonance in the reaction C(O,O)C
No full text
- …
