1,167 research outputs found
Monte Carlo Study of the Inflation-Deflation Transition in a Fluid Membrane
We study the conformation and scaling properties of a self-avoiding fluid
membrane, subject to an osmotic pressure , by means of Monte Carlo
simulations. Using finite size scaling methods in combination with a histogram
reweighting techniques we find that the surface undergoes an abrupt
conformational transition at a critical pressure , from low pressure
deflated configurations with a branched polymer characteristics to a high
pressure inflated phase, in agreement with previous findings
\cite{gompper,baum}. The transition pressure scales with the system
size as , with . Below
the enclosed volume scales as , in accordance with the
self-avoiding branched polymer structure, and for our data
are consistent with the finite size scaling form ,
where .
Also the finite size scaling behavior of the radii of gyration and the
compressibility moduli are obtained. Some of the observed exponents and the
mechanism behind the conformational collapse are interpreted in terms of a
Flory theory.Comment: 20 pages + postscript-file, Latex + Postscript, IFA Report No. 94/1
Short Bowel Patients Treated for Two Years with Glucagon-Like Peptide 2 (GLP-2): Compliance, Safety, and Effects on Quality of Life
Background and aims. Glucagon-like peptide 2 (GLP-2) has been shown to improve intestinal absorption in short bowel syndrome (SBS) patients in a short-term study. This study describes safety, compliance, and changes in quality of life in 11 SBS patients at baseline, week 13, 26, and 52 during two years of subcutaneous GLP-2 treatment, 400 microgram TID, intermitted by an 8-week washout period.
Methods. Safety and compliance was evaluated during the admissions. The Sickness Impact Profile (SIP), Short Form 36 (SF 36), and Inflammatory Bowel Disease Questionnaire (IBDQ) evaluated quality of life.
Results. The predominant adverse event was transient abdominal discomfort in 5 of 11 patients, but in 2, both suffering from Crohns disease, it progressed to abdominal pain and led to discontinuation of GLP-2 treatment. One had a fibrostenotic lesion electively resected at the jejuno-ascendo-anastomosis. The investigator excluded a patient due to unreliable feedback. Stoma nipple enlargement was seen in all 9 jejunostomy patients. Reported GLP-2 compliance was excellent (>93%). GLP-2 improved the overall quality of life VAS-score (4.1 ± 2.8 cm versus 6.0 ± 2.4 cm, P < .01), the overall SIP score (10.3 ± 8.9% versus 6.2 ± 9.5%, P < .001), the mental component of the SF-36 (45 ± 13% versus 53 ± 11%, P < .05), and the overall IBDQ score (5.1 ± 0.9 versus 5.4 ± 0.9, P < .007) in the 8 patients completing the study.
Conclusions. Long-term treatment with GLP-2 is feasible in SBS patients, although caution must be exercised in patients with a history of abdominal pain. Although conclusions cannot be made in a noncontrolled trial, the high reported compliance might reflect a high treatment satisfaction, where the clinical benefits of GLP-2 may outweigh the discomforts of injections
Short Bowel Patients Treated for Two Years with Glucagon-Like Peptide 2: Effects on Intestinal Morphology and Absorption, Renal Function, Bone and Body Composition, and Muscle Function
Background and aims. In a short-term study, Glucagon-like peptide 2 (GLP-2) has been shown to improve intestinal absorption in short bowel syndrome (SBS) patients. This study describes longitudinal changes in relation to GLP-2 treatment for two years.
Methods. GLP-2, 400 micrograms, s.c.,TID, were offered, to eleven SBS patients keeping parenteral support constant. 72-hour nutritional balance studies were performed at baseline, weeks 13, 26, 52 during two years intermitted by an 8-week washout period. In addition, mucosal morphometrics, renal function (by creatinine clearance), body composition and bone mineral density (by DEXA), biochemical markers of bone turnover (by s-CTX and osteocalcin, PTH and vitamin D), and muscle function (NMR, lungfunction, exercise test) were measured. Results. GLP-2 compliance was >93%. Three of eleven patients did not complete the study. In the remaining 8 patients, GLP-2 significantly reduced the fecal wet weight from approximately 3.0 to approximately 2.0 kg/day. This was accompanied by a decline in the oral wet weight intake, maintaining intestinal wet weight absorption and urinary weight constant. Renal function improved. No significant changes were demonstrated in energy intake or absorption, and GLP-2 did not significantly affect mucosal morphology, body composition, bone mineral density or muscle function. Conclusions. GLP-2 treatment reduces fecal weight by approximately 1000 g/d and enables SBS patients to maintain their intestinal fluid and electrolyte absorption at lower oral intakes. This was accompanied by a 28% improvement in creatinine clearance
A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems
We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake
ecosystem model by augmenting the individual cognitive maps drawn by 8
scientists working in the area of shallow lake ecology. We calculated graph
theoretical indices of the individual cognitive maps and the collective
cognitive map produced by augmentation. The graph theoretical indices revealed
internal cycles showing non-linear dynamics in the shallow lake ecosystem. The
ecological processes were organized democratically without a top-down
hierarchical structure. The steady state condition of the generic model was a
characteristic turbid shallow lake ecosystem since there were no dynamic
environmental changes that could cause shifts between a turbid and a clearwater
state, and the generic model indicated that only a dynamic disturbance regime
could maintain the clearwater state. The model developed herein captured the
empirical behavior of shallow lakes, and contained the basic model of the
Alternative Stable States Theory. In addition, our model expanded the basic
model by quantifying the relative effects of connections and by extending it.
In our expanded model we ran 4 simulations: harvesting submerged plants,
nutrient reduction, fish removal without nutrient reduction, and
biomanipulation. Only biomanipulation, which included fish removal and nutrient
reduction, had the potential to shift the turbid state into clearwater state.
The structure and relationships in the generic model as well as the outcomes of
the management simulations were supported by actual field studies in shallow
lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to
understand the complex structure of shallow lake ecosystems as a whole and
obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure
Study of 10Li via the 9Li(2H, p) reaction at REX-ISOLDE
The 9Li + 2H reaction has been investigated at 2.36 MeV/u at the REX-ISOLDE facility. In this Letter we focus on the 10Li + p channel which potentially holds spectroscopic information on the unbound nucleus 10Li. The experimental excitation energy spectrum and angular distribution are compared with CCBA calculations. These calculations clearly support the existence of a low-lying (s) virtual state, with a (negative) scattering length of the order as ∼ 13 - 24 fm and a p1 / 2 resonance with an energy of Er ≃ 0.38 MeV and a width of Γ ≃ 0.2 MeV.European Union Fifth Framework HPRI-CT-1999-00018Comisión Interministerial de Investigaciones Científicas FPA2005-02379 y FPA2005-0446
Hardware-in-the-loop simulation of FPGA-based state estimators for electric vehicle batteries
This paper describes a hardware-in-the-loop (HiL) simulation platform specifically designed to test state estimators for Li-ion batteries in electric vehicle applications. Two promising estimators, the Mix algorithm combined with the moving window least squares and the dual extended Kalman filter, are implemented in hardware on a field-programmable gate array (FPGA) and evaluated using the developed HiL platform. The simulation results show the effectiveness of using FPGAs for hardware acceleration of battery state estimators and the importance of their assessment under different operating conditions, i.e., driving schedules, which can be simulated by the HiL platform
Investigation of the 9Li + 2H → 8Li + t reaction at REX-ISOLDE
The one-neutron transfer reaction 9Li + 2H → 8Li + t has been investigated in an inverse kinematics experiment by bombarding a deuterated polypropylene target with a 2.36 MeV/u 9Li beam from the post-accelerator REX-ISOLDE at CERN. Excitation energies in 8Li as well as angular distributions of the tritons were obtained and spectroscopic factors deducedEuropean Union Fifth Framework HPRI-CT-1999-00018Comisión Interministerial de Ciencia y Tecnología FPA2002-04181-c04-0
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