387 research outputs found
FörÀndringsreceptens institutionaliseringsprocess : En utredning om dold mellanliggande mekanism vid organisationsförÀndring
Problem/Bakgrund: Det finns mÄnga förÀndringsstrategier och modeller, recept, för att förÀndra, men Àven för att organisera verksamheter. Olika modeller och recept kommer och gÄr. Oftast framstÀlls resultatet i olika termer och nÄgot som ofta Äterkommer Àr att graden delaktighet har ökat. Kan det vara sÄ att det Àr graden av delaktighet Àr en dold mekanism som ligger bakom en lyckad förÀndring? Syfte: Mitt syfte med den hÀr uppsatsen Àr att undersöka om det finns ett kausalt orsakssamband mellan betingelserna ledning, ansvar och vÀrdering och hÀndelserna sjukskrivning, personalomsÀttning och pÄverka dÀr delaktighet utgör mekanismen som aktiverar förloppet. Slutsatser/Resultat: Det finns ett kausalt orsakssamband mellan betingelsen ledning och hÀndelserna sjukskrivning, upplevd delaktighet och personalomsÀttning. Orsakssambandet aktiveras av en dolda mellanliggande mekanism, som i det hÀr fallet Àr vÀrderingar inte som först antagits, delaktighet. Delaktighet visade sig vara en hÀndelse
Electric Versus Manual Tooth Brushing among Neuroscience ICU Patients: Is it Safe?
Poor oral hygiene has been associated with ventilator-acquired pneumonia. Yet providing oral care for intubated patients is problematic. Furthermore, concerns that oral care could raise intracranial pressure (ICP) may cause nurses to use foam swabs to provide oral hygiene rather than tooth brushing as recommended by the American Association of Critical-Care Nurses. Evidence is needed to support the safety of toothbrushing during oral care. We therefore evaluated ICP and cerebral perfusion pressure (CPP) during oral care with a manual or electric toothbrush in intubated patients in a neuroscience intensive care unit (ICU). As part of a larger 2-year, prospective, randomized clinical trial, 47 adult neuroscience ICU patients with an ICP monitor received oral care with a manual or electric toothbrush. ICP and CPP were recorded before, during, and after oral care over the first 72 h of admission. Groups did not differ significantly in age, gender, or severity of injury. Of 807 ICP and CPP measurements obtained before, during, and after oral care, there were no significant differences in ICP (P = 0.72) or CPP (P = 0.68) between toothbrush methods. Analysis of pooled data from both groups revealed a significant difference across the three time points (Wilks' lambda, 12.56; P < 0.001; partial eta(2), 0.36). ICP increased significantly (mean difference, 1.7 mm Hg) from before to during oral care (P = 0.001) and decreased significantly (mean difference, 2.1 mm Hg) from during to after oral care (P < 0.001). In the absence of preexisting intracranial hypertension during oral care, tooth brushing, regardless of method, was safely performed in intubated neuroscience ICU patients
Chemical Looping Combustion and Chemical Looping with Oxygen Uncoupling Experiments in a Batch Reactor Using Spray-Dried CaMn1âxMxO3âÎŽ (M = Ti, Fe, Mg) Particles as Oxygen Carriers
Chemical looping combustion and chemical looping with oxygen uncoupling (CLOU) with oxygen carrier particles consisting of CaMn1-xMxO3-delta (M = Ti, Fe, Mg) has been studied by consecutive oxidation and reduction experiments in a fluidized-bed batch reactor. The examined particles were produced by spray drying, and all did show a significant release of gas-phase oxygen to the inert atmosphere at 900 and 1000 degrees C. All particles also provided very high reactivity with syngas and methane. Some of the examined particles showed unfavorable fluidization characteristics, i.e., they formed dust during operation or showed agglomeration or defluidization tendencies. The crushing strength of the particles that formed dust was typically <1.2 N. The desired perovskite structure was detected in all samples by X-ray diffractometry. The materials that included iron and titanium had these elements incorporated in the perovskite structure, substituting manganese. When magnesium had been included, it was not incorporated into the crystal structure; instead, it was present as a separate phase of MgO. In addition to a perovskite phase, most samples also contained small amounts of marokite (CaMn2O4). Particles doped with MgO calcined at 1300 degrees C showed good fluidization behavior, as well as particularly high reactivity with fuel
Combined Oxides of Iron, Manganese and Silica as Oxygen Carriers for Chemical-Looping Combustion
Spray-dried particles with the chemical compositions of Fe0.66Mn1.33SiO3 and FeMnSiO3 have been examined as oxygen carrier materials for chemical-looping combustion. The performance of the materials was examined in oxygen release experiments and during fuel operation with natural gas and syngas. The experiments were carried out in a fluidized-bed chemical-looping reactor system designed for a thermal power of 300 W. The reactor system includes an air reactor and a fuel reactor, as well as loop seals and means for circulation of the oxygen carrier particles. Both materials were able to release gas phase oxygen in inert atmosphere at temperatures between 800-950°C, and with approximately equal oxygen concentrations. Fe0.66Mn1.33SiO3 provided higher conversion of natural gas as compared to FeMnSiO3 and the fuel conversion increased with temperature for both materials. During natural gas operation with Fe0.66Mn1.33SiO3 the conversion reached 100% at around 950°C with a fuel reactor inventory of 235 kg/MW. The fuel conversion was improved when the solids inventory was increased; this improvement could especially be observed for FeMnSiO3 as the fuel conversion was lower for this material. Fe0.66Mn1.33SiO3 provided higher fuel conversion than FeMnSiO3 also when syngas was used as fuel. The fuel conversion increased with temperature for both materials and full conversion was reached above 800°C with a fuel reactor inventory of 225 kg/MW for Fe0.66Mn1.33SiO3, while FeMnSiO3 was incapable of providing full conversion. A rather large elutriation of fines and a significant change in particle size distribution could be observed during operation for both materials.
Both materials could work as oxygen carrier for chemical-looping with oxygen uncoupling. Fe0.66Mn1.33SiO3 would be preferred as it has higher conversion of both syngas and natural gas, but the attrition behavior of the material would need to be further investigated
Numerical renormalization group study of the correlation functions of the antiferromagnetic spin- Heisenberg chain
We use the density-matrix renormalization group technique developed by White
\cite{white} to calculate the spin correlation functions
for isotropic Heisenberg rings up to
sites. The correlation functions for large and are found to obey
the scaling relation
proposed by Kaplan et al. \cite{horsch} , which is used to determine
. The asymptotic correlation function and
the magnetic structure factor show logarithmic corrections
consistent with , where is related
to the cut-off dependent coupling constant , as
predicted by field theoretical treatments.Comment: Accepted in Phys. Rev. B. 4 pages of text in Latex + 5 figures in
uuencoded form containing the 5 postscripts (mailed separately
Interpersonal violence, early life adversity, and suicidal behavior in hypersexual men
There are significant gaps in knowledge regarding the role of childhood adversity, interpersonal violence, and suicidal behavior in hypersexual disorder (HD). The aim of this study was to investigate interpersonal violence in hypersexual men compared with healthy volunteers and the experience of violence in relation to suicidal behavior. Methods This caseâcontrol study includes 67 male patients with HD and 40 healthy male volunteers. The Childhood Trauma Questionnaire â Short Form (CTQ-SF) and the Karolinska Interpersonal Violence Scale (KIVS) were used for assessing early life adversity and interpersonal violence in childhood and in adult life. Suicidal behavior (attempts and ideation) was assessed with the Mini-International Neuropsychiatric Interview (version 6.0) and the MontgomeryâĂ
sberg Depression Rating Scale â Self-rating. Results Hypersexual men reported more exposure to violence in childhood and more violent behavior as adults compared with healthy volunteers. Suicide attempters (n = 8, 12%) reported higher KIVS total score, more used violence as a child, more exposure to violence as an adult as well as higher score on CTQ-SF subscale measuring sexual abuse (SA) compared with hypersexual men without suicide attempt. Discussion Hypersexuality was associated with interpersonal violence with higher total scores in patients with a history of suicide attempt. The KIVS subscale exposure to interpersonal violence as a child was validated using the CTQ-SF but can be complemented with questions focusing on SA for full assessment of early life adversity. Conclusion Childhood adversity is an important factor in HD and interpersonal violence might be related to suicidal behavior in hypersexual men
Oxygen-Carrier Development of Calcium ManganiteâBased Materials with Perovskite Structure for Chemical-Looping Combustion of Methane
The present work is related to the upscaling of calcium manganiteâbased oxygen-carrier materials, which have a perovskite structure, both with respect to the use of inexpensive raw materials, i.e., instead of pure chemicals, and the upscaling of production to multitonne batches. Results are presented from the two different stages of material development, i.e., raw material selection and upscaling. The evaluation involves both operation in chemical-looping combustor units of 300 W and 10 kW, and material characterization. In the latter unit, the gas velocities in the riser and in the grid-jet zone of the gas distributor come close to gas velocities of industrial-scale units and, therefore, this unit is also used to assess particle lifetime. Results from the various chemical-looping combustion units and oxygen-carrier materials produced from various raw materials of both high and low purity show that very high degrees of fuel conversion can be reached while achieving very high oxygen-carrier lifetimes. The composition of the oxygen-carrier materials seems robust and flexible with respect to the precursors used in its manufacturing
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