Zeitschriftenartikel: „Pressures for change“

1

Mendelowitz, D., und A. M. Scher. „Pulsatile sinus pressure changes evoke sustained baroreflex responses in awake dogs“. American Journal of Physiology-Heart and Circulatory Physiology 255, Nr. 3 (01.09.1988): H673—H678. http://dx.doi.org/10.1152/ajpheart.1988.255.3.h673.

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A modified Stephenson-Donald preparation was used to control pressure in an isolated carotid sinus in conscious dogs with all other arterial baroreceptors denervated. Sinus pressure was changed from preisolation control levels to either an elevated static or an elevated pulsatile pressure for 5 min. These sinus pressure changes evoked similar initial decreases in arterial pressure. The elevated static sinus pressure (150 or 175 mmHg) caused an initial depressor response of -32.7 +/- 5.5 mmHg, which then decayed rapidly. Five minutes after the change in sinus pressure, the depressor response was abolished, as arterial pressure returned to control pressure. This decay of the response would be expected if resetting occurred. In contrast, when the sinus was exposed to elevated pulsatile pressures (125 or 150 mmHg mean, 50 mmHg pulse pressure) depressor responses were sustained throughout the sinus pressure change (-23.2 +/- 5.3 mmHg initial, -29.0 +/- 4.8 mmHg at 5 min; P greater than 0.4). These results demonstrate that while the reflex responses rapidly reset to elevated static sinus pressures, elevated pulsatile pressures elicit sustained reflex responses.

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2

Carolan, Brian V. „Institutional Pressures and Isomorphic Change“. Education and Urban Society 40, Nr. 4 (23.10.2007): 428–51. http://dx.doi.org/10.1177/0013124507304686.

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3

Tyler, Mark. „INDOOR POLLUTION – PRESSURES FOR CHANGE“. Facilities 9, Nr. 9 (September 1991): 7–9. http://dx.doi.org/10.1108/eum0000000002157.

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4

Walton, Peter. „International pressures for accounting change“. British Accounting Review 22, Nr. 3 (September 1990): 295–97. http://dx.doi.org/10.1016/0890-8389(90)90016-b.

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5

Lock, Simon J., und Sarah T. Stewart. „Giant impacts stochastically change the internal pressures of terrestrial planets“. Science Advances 5, Nr. 9 (September 2019): eaav3746. http://dx.doi.org/10.1126/sciadv.aav3746.

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Pressure is a key parameter in the physics and chemistry of planet formation and evolution. Previous studies have erroneously assumed that internal pressures monotonically increase with the mass of a body. Using smoothed particle hydrodynamics and potential field method calculations, we demonstrate that the hot, rapidly rotating bodies produced by giant impacts can have much lower internal pressures than cool, slowly rotating planets of the same mass. Pressures subsequently increase because of thermal and rotational evolution of the body. Using the Moon-forming impact as an example, we show that the internal pressures after the collision could have been less than half that in present-day Earth. The current pressure profile was not established until Earth cooled and the Moon receded, a process that may take up to tens of millions of years. Our work defines a new paradigm for pressure evolution during accretion of terrestrial planets: stochastic changes driven by impacts.

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6

Haque, Shamima, und Muhammad Azizul Islam. „Stakeholder pressures on corporate climate change-related accountability and disclosures: Australian evidence“. Business and Politics 17, Nr. 2 (August 2015): 355–90. http://dx.doi.org/10.1017/s1369525800001674.

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This study investigates stakeholder pressures on corporate climate change-related accountability and disclosure practices in Australia. While existing scholarship investigates stakeholder pressures on companies to discharge their broader accountability through general social and environmental disclosures, there is a lack of research investigating whether and how stakeholder pressures emerge to influence accountability and disclosure practices related to climate change. We surveyed various stakeholder groups to understand their concerns about climate change-related corporate accountability and disclosure practices. We present three primary findings: first, while NGOs and the media have some influence, institutional investors and government bodies (regulators) are perceived to be the most powerful stakeholders in generating climate change-related concern and coercive pressure on corporations to be accountable. Second, corporate climate change-related disclosures, as documented through the Carbon Disclosure Project (CDP), are positively associated with such perceived coercive pressures. Lastly, we find a positive correlation between the level of media attention to climate change and Australian corporate responses to the CDP. Our results indicate that corporations will not disclose climate change information until pressured by non-financial stakeholders. This suggests a larger role for non-financial actors than previously theorized, with several policy implications.

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7

Trapateau, Nicolas, und Jean-Louis Duchet. „Change from Above and Resistance to Change in the Early Prescriptive Pronouncing Dictionaries of English“. Studia Anglica Posnaniensia 54, s1 (01.12.2019): 315–36. http://dx.doi.org/10.2478/stap-2019-0015.

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AbstractTo what extent is it possible to interpret the data of pronouncing dictionaries of the 18th century in sociolinguistic terms? Several answers are provided by resorting to Labov’s concepts of change from above and change from below the level of awareness. A systematic investigation of John Walker’s Critical Pronouncing Dictionary (1791, 1809), the most complete and cumulative of all such dictionaries of the time, makes it possible to show that an orthoepist like Walker often reflects the pressure in favour of change from above for vowel quality and resistance to such a change in matters of stress placement. By preferring analogy to conservative pronunciations due to his bias in favour of a rational pattern, Walker also links analogy to the “vernacular instinct”, promoting variant forms witnessing a change from below. And many other changes under way in his time, which pass unnoticed in the orthoepist’s discourse and transcriptions, properly deserve to be treated as changes from below, thus making his dictionary the common ground for pressures from above and pressures from below.Walker’s prescription is a complex combination of both promotion of, and resistance to pressures from above according to criteria that reflect the ideals of the upper middle class.

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Zhang, Liming, Shengqun Jiang und Jin Yu. „Experimental Research into the Evolution of Permeability of Sandstone under Triaxial Compression“. Energies 13, Nr. 19 (27.09.2020): 5065. http://dx.doi.org/10.3390/en13195065.

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Failure tests on sandstone specimens were conducted under different confining pressures and seepage pressures by using an MTS triaxial rock testing machine to elucidate the corresponding correlations of permeability and characteristic stress with confining pressure and pore pressure during deformation. The results indicate that permeability first decreases and presents two trends, i.e., a V-shaped increase and an S-shaped trend during the non-linear deformation stage. The greater the seepage pressure, the greater the initial permeability and the more obvious the V-shaped trend in the permeability. As the confining pressure was increased, the trend in the permeability gradually changed from V- to S-shaped. Compared with the case at a high confining pressure, the decrease of permeability occurred more quickly, the rate of change becomes greater, and the sudden increase observed in the permeability happened earlier under lower confining pressures. Within the range tested, confining pressure exerted a greater effect on the permeability than the seepage pressure. In comparison with the axial strain, volumetric strain better reflected changes in permeability during compaction and dilation of sandstone. The ratio of crack initiation stress to peak strength ranged from 0.37 to 0.50, while the ratio of dilation stress to peak strength changed from 0.58 to 0.72. Permeabilities calculated based on Darcy and non-Darcy flow changed within the same interval, while the change in permeability was different.

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9

Rassenfoss, Stephen. „Offshore Seismic Feeling Pressures to Change“. Journal of Petroleum Technology 68, Nr. 01 (01.01.2016): 32–37. http://dx.doi.org/10.2118/0116-0032-jpt.

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10

Allen, Ronald J. „The Pressures and Prospects for Change“. Journal of Criminal Law and Criminology (1973-) 81, Nr. 1 (1990): 1. http://dx.doi.org/10.2307/1143776.

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11

Hawtrey, KM. „Modern Central Banking: Pressures for Change“. Australian Journal of Public Administration 56, Nr. 1 (März 1997): 59–70. http://dx.doi.org/10.1111/j.1467-8500.1997.tb01242.x.

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12

Isnikurniawan, Ahmad, Yasuhiro Fujita, Sachio Tanimoto und Tatsuo Sawada. „Investigation of Cluster Formation in MR Fluid under Compression Using Ultrasonic Measurement“. Materials Science Forum 792 (August 2014): 147–52. http://dx.doi.org/10.4028/www.scientific.net/msf.792.147.

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This paper reports measurement results of ultrasonic propagation velocity in MR fluid under compression. Experiments were conducted by applying different pressures in MR fluid at constant magnetic flux density. At low magnetic flux densities (100 and 200 mT), the ultrasonic propagation velocity in MR fluids changes when subjected to pressure. This change is related to cluster formation in MR fluid. The ultrasonic propagation velocity change is smaller when higher pressures are applied, indicating that cluster size in MR fluid becomes thinner under higher pressures. However, at higher magnetic flux densities (300 and 400 mT), ultrasonic propagation velocities under different pressures are nearly similar. These results indicate that at higher magnetic flux densities, pressures do not affect cluster formation in MR fluids.

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13

Christensen, N. I., und H. F. Wang. „The Influence of pore pressure and confining pressure on dynamic elastic properties of Berea sandstone“. GEOPHYSICS 50, Nr. 2 (Februar 1985): 207–13. http://dx.doi.org/10.1190/1.1441910.

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Compressional‐ and shear‐wave velocities of watersaturated Berea sandstone have been measured as functions of confining and pore pressures to 2 kbar. The velocities, measured by the pulse transmission technique, were obtained at selected pressures for the purpose of evaluating the relative importance of confining pressure and pore pressure on elastic wave velocities and derived dynamic elastic constants. Changes in Berea sandstone velocities resulting from changes in confining pressure are not exactly canceled by equivalent changes in pore pressure. For properties that involve significant bulk compression (compressional‐wave velocities and bulk modulus) an incremental change in pore pressure does not entirely cancel a similar change in confining pressure. On the other hand, it is shown that a pore pressure increment more than cancels an equivalent change in confining pressure for properties that depend significantly on rigidity (shear‐wave velocity and Poisson’s ratio). This behavior (as well as observed wave amplitudes) is related to the presence of high‐compressibility clay that lines grains and pores within the quartz framework of the Berea sandstone.

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14

Glucksberg, M. R., und J. Bhattacharya. „Effect of alveolar and pleural pressures on interstitial pressures in isolated dog lungs“. Journal of Applied Physiology 70, Nr. 2 (01.02.1991): 914–18. http://dx.doi.org/10.1152/jappl.1991.70.2.914.

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We report the first direct measurements of perialveolar interstitial pressures in lungs inflated with negative pleural pressure. In eight experiments, we varied surrounding (pleural) pressure in a dog lung lobe to maintain constant inflation with either positive alveolar and ambient atmospheric pleural pressures (positive inflation) or ambient atmospheric alveolar and negative pleural pressures (negative inflation). Throughout, vascular pressure was approximately 4 cmH2O above pleural pressure. By the micropuncture servo-null technique we recorded interstitial pressures at alveolar junctions (Pjct) and in the perimicrovascular adventitia (Padv). At transpulmonary pressure of 7 cmH2O (n = 4), the difference of Pjct and Pady from pleural pressure of 0.9 +/- 0.4 and -1.1 +/- 0.2 cmH2O, respectively, during positive inflation did not significantly change (P less than 0.05) after negative inflation. After increase of transpulmonary pressure from 7 to 15 cmH2O (n = 4), the decrease of Pjct by 3.3 +/- 0.3 cmH2O and Pady by 2.0 +/- 0.4 cmH2O during positive inflation did not change during negative inflation. The Pjct-Pady gradient was not affected by the mode of inflation. Our measurements indicate that, in lung, when all pressures are referred to pleural or alveolar pressure, the mode of inflation does not affect perialveolar interstitial pressures.

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15

Scharf, S. M., L. M. Graver, S. Khilnani und K. Balaban. „Respiratory phasic effects of inspiratory loading on left ventricular hemodynamics in vagotomized dogs“. Journal of Applied Physiology 73, Nr. 3 (01.09.1992): 995–1003. http://dx.doi.org/10.1152/jappl.1992.73.3.995.

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Exaggerated inspiratory swings in intrathoracic pressure have been postulated to increase left ventricular (LV) afterload. These predictions are based on measurements of LV afterload by use of esophageal or lateral pleural pressure. Using direct measurements of pericardial pressure, we reexamined respiratory changes in LV afterload. In 11 anesthetized vagotomized dogs, we measured arterial pressure, LV end-systolic (ES) and end-diastolic transmural (TM) pressures, stroke volume (SV), diastolic left anterior descending blood flow (CBF-D), and coronary resistance. Dogs were studied before and while breathing against an inspiratory threshold load of -20 to -25 cmH2O compared with end expiration. Relative to end expiration, SV and LVES TM pressures decreased during inspiration and increased during early expiration, effects exaggerated during inspiratory loading. In all cases, LV afterload (LVES TM pressure) changed in parallel with SV. LV end-diastolic TM pressure did not change. CBF-D paralleled arterial pressure, and there were no changes in coronary resistance. In two dogs, regional LVES segment length paralleled calculated changes in LVES TM pressure. We conclude that 1) LV afterload decreases during early inspiration and increases during early expiration, changes secondary to those in SV; 2) changes in CBF-D are secondary to changes in perfusion pressure during the respiratory cycle; and 3) the use of esophageal or lateral pleural pressure to estimate LV surface pressure overestimates changes in LV TM pressures during respiration.

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16

Maass-Moreno, R., und C. F. Rothe. „Nonlinear resistances in hepatic microcirculation“. American Journal of Physiology-Heart and Circulatory Physiology 269, Nr. 6 (01.12.1995): H1922—H1930. http://dx.doi.org/10.1152/ajpheart.1995.269.6.h1922.

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The liver provides a reservoir available for mobilizing large amounts of blood, but if a change in downstream (outflow) pressure below a certain magnitude (break pressure) does not change upstream pressures, blood volume redistribution may be limited. For downstream pressures larger than the break pressure, the upstream pressures change proportionately. We tested the hypothesis that this nonlinear mode of pressure transmission could be found from the abdominal vena cava to the hepatic microcirculation and from the hepatic microcirculation to the portal vein. Using a servo-null micropipette technique, we measured microvascular pressures at the liver surface of rabbits. In 16 of 30 measurements, increasing the pressure at the liver outflow, by partially occluding the caudal thoracic vena cava, caused an increase in hepatic venular pressure only after the abdominal vena caval pressure exceeded a break pressure of 2.85 +/- 0.92 mmHg. In 13 of 31 measurements, portal venous pressure was not changed until the hepatic venular pressure exceeded a break pressure of 3.36 +/- 0.54 mmHg. Similar behavior and values were obtained for sinusoids and portal venules. When present, the sharp inflection in the upstream-downstream pressure plots suggests that this may be caused by a Starling resistor-type mechanism. When the break was absent, the downstream pressure may have been larger than the break pressure. We conclude that significant hepatic resistances with nonlinear characteristics exist upstream and downstream to the central venules, sinusoids, and portal venules.

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17

Sandmann, M., und A. Würflinger. „PVT Measurements on 4′-n-Octyl-Biphenyl-4-Carbonitrile (8CB) up to 300 MPa“. Zeitschrift für Naturforschung A 53, Nr. 9 (01.09.1998): 787–92. http://dx.doi.org/10.1515/zna-1998-0910.

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Abstract P, Vm , Tdata have been measured for the smectic, nematic and isotropic phases of 4'-n-octyl-biphen-yl-4-carbonitrile (8CB) in the temperature range 300-370 K and pressures up to 300 MPa. At atmospheric pressure all phase transitions appear to be of first order due to a discontinuity in the density. The volume change at the smectic A -nematic transition is only a tenth of the volume change at the clearing temperature. At moderate pressures below 80 MPa the SA -N transition could be detected as a discontinuity in the period of oscillation in measurements with a high-pressure vibrating tube densimeter. At higher pressures the discontinuity seems to die away, possibly indicating a change from first order to second order transition. From the volume changes and the slopes of the transition lines we calculate the enthalpy changes at the phase transition. The p, Vm , T data enable us to calculate the volume part of the entropy and the molecular field parameter γ=δln TNI/δln VNI .

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18

Rubal, B. J., M. R. Geer und W. H. Bickell. „Effects of pneumatic antishock garment inflation in normovolemic subjects“. Journal of Applied Physiology 67, Nr. 1 (01.07.1989): 339–45. http://dx.doi.org/10.1152/jappl.1989.67.1.339.

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This study examines the effects of inflation of pneumatic antishock garments (PASG) in 10 normovolemic men (mean age 44 +/- 6 yr) undergoing diagnostic catheterization. Seven subjects had normal heart function and no evidence of coronary artery disease (CAD); three patients had CAD. High-fidelity multisensor catheters were employed to simultaneously record right and left heart pressures before PASG inflation and after inflation to 40, 70, and 100 mmHg. A thermal dilution catheter was used to obtain pulmonary capillary wedge pressure and cardiac output. Counterpressure increases greater than or equal to 40 mmHg were associated with significant changes in left and right heart pressures. Right and left ventricular end-diastolic pressures increased 100% (P less than 0.01); mean pulmonary arterial and aortic pressures increased 77 and 25%, respectively (P less than 0.01); systemic vascular resistance increased 22% (P less than 0.05) and pulmonary vascular resistance did not change in normal subjects at maximum PASG inflation. Heart rate, cardiac output, and aortic and pulmonary arterial pulse pressures did not change during inflation in either group. Right and left ventricular end-diastolic pressures and pulmonary capillary wedge pressure were greater (P less than 0.05) in the CAD group compared with the normal subjects during PASG inflation. The data suggest that the primary mechanism whereby PASG inflation induces changes in central hemodynamics in normovolemic subjects is through an acute increase in left ventricular afterload. PASG changes in afterload and pulmonary capillary wedge pressure imply that these devices should be used with caution in patients with compromised cardiac function.

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19

Davis, M. J. „Microvascular control of capillary pressure during increases in local arterial and venous pressure“. American Journal of Physiology-Heart and Circulatory Physiology 254, Nr. 4 (01.04.1988): H772—H784. http://dx.doi.org/10.1152/ajpheart.1988.254.4.h772.

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The extent to which capillary hydrostatic pressure might be protected from increases in local arterial and venous pressure was examined in the wing microcirculation of unanesthetized pallid bats (Antrozous pallidus). Arterial inflow and venous outflow pressures to the wing were elevated using a box technique to increase pressure around the body of the animal in steps of 12 mmHg between 0 and +60 mmHg for 3-min periods. During this time, hydrostatic pressure, diameter, and red cell velocity in single microvessels were continuously recorded. All branching orders of arterioles constricted significantly during increases in box pressure (Pb), while capillaries and venules dilated. First-order arteriole and venule pressures increased 1:1 with Pb. Capillary pressures increased by only a fraction of Pb up to +36 mmHg, but at higher Pb, the change in capillary pressure was equivalent to the change in Pb. Calculations of vascular resistance indicate that changes in both pre- and postcapillary resistance in this tissue act to prevent increases in capillary pressure during moderate, but not during large, increases in arterial and venous pressure.

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20

Gross, James G. „Codes, Standards, and Institutions—Pressures for Change“. Journal of Professional Issues in Engineering Education and Practice 117, Nr. 2 (April 1991): 75–87. http://dx.doi.org/10.1061/(asce)1052-3928(1991)117:2(75).

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21

Bhargava, Alok. „Climate change, demographic pressures and global sustainability“. Economics & Human Biology 33 (Mai 2019): 149–54. http://dx.doi.org/10.1016/j.ehb.2019.02.007.

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22

Hodge, Gerald. „The pressures of change in rural Canada“. Journal of Rural Studies 1, Nr. 3 (Januar 1985): 285. http://dx.doi.org/10.1016/0743-0167(85)90111-1.

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23

Richards, A. M., H. Ikram, M. G. Nicholls, E. A. Espiner, E. J. Hamilton und R. D. Richards. „Ambulatory pulmonary arterial pressures in humans: relationship to arterial pressure and hormones“. American Journal of Physiology-Heart and Circulatory Physiology 251, Nr. 1 (01.07.1986): H101—H108. http://dx.doi.org/10.1152/ajpheart.1986.251.1.h101.

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Six healthy volunteers were studied by use of a continuous ambulatory recording technique to document the normal range and variability of pulmonary artery pressure (PAP) and to examine its relationship to systemic arterial pressure (SAP) both at rest and during standardized interventions. Vasoactive hormone levels were measured at frequent intervals. Over 8-10 h of study the mean PAP was 15.7/6.3 mmHg. Parallel changes in PAP and SAP were observed at rest and during exercise and eating. On the contrary, PAP rose and SAP fell with hypoxia, whereas smoking was associated with a rise in SAP but no change in PAP. Sympathetic nervous system activity, as gauged by plasma norepinephrine levels, may have contributed to pressure and heart rate changes during exercise and smoking, but activity of the renin-angiotensin system was not altered by any of the maneuvers. These results provide base-line information on the level of PAP and its variability in healthy volunteers under standardized conditions. Pressures within the systemic and pulmonary circuits change in parallel under some circumstances but move in opposite directions under other conditions.

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Fahey, Shireen J. „Curriculum change and climate change: Inside outside pressures in higher education“. Journal of Curriculum Studies 44, Nr. 5 (Oktober 2012): 703–22. http://dx.doi.org/10.1080/00220272.2012.679011.

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25

Murray, E. J., und J. D. Geddes. „A conceptual model for clay soils subjected to negative pore-water pressures“. Canadian Geotechnical Journal 32, Nr. 5 (01.10.1995): 905–12. http://dx.doi.org/10.1139/t95-087.

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Understanding and predicting the volume change behaviour of soils subjected to negative pore-water pressures presents a complex problem that requires a sound theoretical model matched to experimental evidence. A complete model must cover both saturated and unsaturated behaviour and relate stress levels to pore-water pressures and volume changes. A conceptual model for clay soils is presented which employs the principles of critical state soil mechanics. In developing the model, consideration is given to negative pore-water pressures arising as a result of the independent response to reductions in water content and reductions in confining stresses. In this way the limits of the conceptual model are defined. Key words : suction, negative pore-water pressure, volume change, unsaturated soil, critical state.

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Nellis, S. H., und L. Whitesell. „Phasic pressures and diameters in small epicardial veins of the unrestrained heart“. American Journal of Physiology-Heart and Circulatory Physiology 257, Nr. 4 (01.10.1989): H1056—H1061. http://dx.doi.org/10.1152/ajpheart.1989.257.4.h1056.

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Previous data from this laboratory have revealed a large pressure pulse in small veins on the epicardial surface of the right ventricle of the rabbit. The phasic relationship between venule pressures and venule diameters in a beating heart was examined. Luminal pressures were measured in 39 different veins on the epicardial surface of the rabbit right ventricle. The venous luminal pressures averaged 12.6 mmHg maximum and 1.0 mmHg minimum. Pressures in 23 different small veins were also obtained at different right ventricular afterloads. Peak venous pressures increased with peak right ventricular pressure. The phasic diameter changes of 119 different vessels were examined. Vessel diameters decreased as luminal pressures increased. The average change in vessel diameter through a cardiac cycle was 20%, with a range from 0 to 60%. The large pulse pressures found in small veins appear to be related to decreasing vessel diameters and probably result from the displacement of blood as the vessels narrow.

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Iwase, Kazuhiro, Tetsuto Takao, Hirotoshi Watanabe, Yasuhiro Tanaka, Tetsuo Kido, Noritusugu Ogawa, Norio Ono und Hiroshi Yoshitake. „Intra-Abdominal Venous Pressure During Laparoscopic Cholecystectomy“. HPB Surgery 8, Nr. 1 (01.01.1994): 13–17. http://dx.doi.org/10.1155/1994/13689.

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Superior vena cava (SVC) and inferior vena cava (IVC) pressures were measured serially during laparoscopic cholecystectomy in which the intra-abdominal pressure was maintained at 12mmHg. The influences of alteration of position from 15 degrees head-down to 15 degrees head-up and of the operative procedure of holding the gallbladder up to the right subphrenic space on SVC and IVC pressures were mild. IVC pressure was maintained almost equal to the intra-abdominal pressure during prolonged continuous pneumoperitoneum lasting longer than 60min, while SVC pressure did not change significantly during operation. The discrepancy between SVC and IVC pressures underwent no change during continuous pneumoperitoneum.

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GOERRES, ACHIM, STAFFAN KUMLIN und RUNE KARLSEN. „Pressure without Pain: What Politicians (Don’t) Tell You about Welfare State Change“. Journal of Social Policy 48, Nr. 4 (28.03.2019): 861–84. http://dx.doi.org/10.1017/s0047279419000138.

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AbstractHow do political leaders politicise welfare state “reform pressures”, e.g. unemployment, ageing or globalisation, in election campaigns? Competing expectations range from no politicization at all to a clear and unbiased coupling between pressures and intended policy responses. Eighteen speeches held by prime ministerial candidates at election-year party congresses in Germany, Norway and Sweden (2000–2010) reveal an unfinished and biased problem-solution coupling. On the one hand, even in these affluent countries pressures are frequently politicised. On the other hand, leaders either cherry-pick less painful policy solutions, or refrain altogether from debating them. So, while citizens learn that the welfare state is pressured, they are not exposed to the full range of policies they increasingly have reason to expect after elections.

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Huang, Ya Nan, Xiao Wen Zhao, Xiao Qun Dai und Ya Ning Li. „Effects of Girdle Pressure on Skin Blood Flow“. Advanced Materials Research 175-176 (Januar 2011): 849–52. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.849.

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The safety and comfort play more and more important roles in foundation wear design. In this paper, the change of skin blood flow under pressure is focused on. Three healthy young females were recruited to participate in the experiment. The subjects were required to wear girdles of different design, and the pressures and skin blood flow at five feature points were measured by using AMI system. Moreover, pressures of different magnitudes were exerted at the convex points of pelvis and hip by using the AMI pressure chamber, the change of skin blood flow under these pressures were observed. Some conclusions were drawn as follows: the pressure distribution under girdle was not uniform on skin surface; SBF increased under pressures, but it turned to decrease if pressure was very high; the skin pressure could be eased to varing degrees by the soft tissue, and SBF was influenced by the pressure exerted on capillaries rather than skin pressure.

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Yan, Xinlu, Songhang Zhang, Shuheng Tang, Zhongcheng Li, Yongxiang Yi, Qian Zhang, Qiuping Hu und Yuxin Liu. „A Comprehensive Coal Reservoir Classification Method Base on Permeability Dynamic Change and Its Application“. Energies 13, Nr. 3 (03.02.2020): 644. http://dx.doi.org/10.3390/en13030644.

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Due to the unique adsorption and desorption characteristics of coal, coal reservoir permeability changes dynamically during coalbed methane (CBM) development. Coal reservoirs can be classified using a permeability dynamic characterization in different production stages. In the single-phase water flow stage, four demarcating pressures are defined based on the damage from the effective stress on reservoir permeability. Coal reservoirs are classified into vulnerable, alleviative, and invulnerable reservoirs. In the gas desorption stage, two demarcating pressures are used to quantitatively characterize the recovery properties of permeability based on the recovery effect of the matrix shrinkage on permeability, namely the rebound pressure (the pressure corresponding to the lowest permeability) and recovery pressure (the pressure when permeability returns to initial permeability). Coal reservoirs are further classified into recoverable and unrecoverable reservoirs. The physical properties and influencing factors of these demarcating pressures are analyzed. Twenty-six wells from the Shizhuangnan Block in the southern Qinshui Basin of China were examined as a case study, showing that there is a significant correspondence between coal reservoir types and CBM well gas production. This study is helpful for identifying geological conditions of coal reservoirs as well as the productivity potential of CBM wells.

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Bairagi, Samiran, Kenneth Järrendahl, Fredrik Eriksson, Lars Hultman, Jens Birch und Ching-Lien Hsiao. „Glancing Angle Deposition and Growth Mechanism of Inclined AlN Nanostructures Using Reactive Magnetron Sputtering“. Coatings 10, Nr. 8 (07.08.2020): 768. http://dx.doi.org/10.3390/coatings10080768.

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Glancing angle deposition (GLAD) of AlN nanostructures was performed at room temperature by reactive magnetron sputtering in a mixed gas atmosphere of Ar and N2. The growth behavior of nanostructures shows strong dependence on the total working pressure and angle of incoming flux. In GLAD configuration, the morphology changed from coalesced, vertical nanocolumns with faceted terminations to highly inclined, fan-like, layered nanostructures (up to 38°); while column lengths decreased from around 1743 to 1068 nm with decreasing pressure from 10 to 1.5 mTorr, respectively. This indicates a change in the dominant growth mechanism from ambient flux dependent deposition to directional ballistic shadowing deposition with decreasing working pressures, which is associated with the change of energy and incident angle of incoming reactive species. These results were corroborated using simulation of metal transport (SiMTra) simulations performed at similar working pressures using Ar and N separately, which showed the average particle energy and average angle of incidence decreased while the total average scattering angle of the metal flux arriving at substrate increased with increasing working pressures. Observing the crystalline orientation of GLAD deposited wurtzite AlN nanocolumns using X-ray diffraction (XRD), pole-figure measurements revealed c-axis <0001> growth towards the direction of incoming flux and a transition from fiber-like to biaxial texture took place with increasing working pressures. Under normal deposition conditions, AlN layer morphology changed from {0001} to {101¯1} with increasing working pressure because of kinetic energy-driven growth.

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Greene, A. S., und A. A. Shoukas. „Changes in canine cardiac function and venous return curves by the carotid baroreflex“. American Journal of Physiology-Heart and Circulatory Physiology 251, Nr. 2 (01.08.1986): H288—H296. http://dx.doi.org/10.1152/ajpheart.1986.251.2.h288.

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Venous return curves and cardiac function relationships were simultaneously determined in 10 pentobarbital-anesthetized dogs at three different isolated carotid sinus pressures. Changing carotid sinus pressure (CSP) between 50 and 200 mmHg produced large changes in the zero flow intercept of the venous return curves from 15.37 +/- 0.97 to 11.94 +/- 1.36 mmHg (P less than 0.001) but no change in slope. These changes in the intercept of the venous return curve were due to alterations in systemic vascular capacity caused by the carotid sinus baroreceptor reflex. Changes in the cardiac function curve with baroreceptor pressure were masked by concomitant changes in arterial pressure afterload; however, when arterial pressure was controlled, there was a significant change in the slope of the cardiac function curve from 60.32 +/- 26.9 to 37.06 +/- 13.31 ml X min-1 X kg-1 X mmHg-1 as CSP was changed from 50 to 200 mmHg. We conclude that changes in vascular capacity are the primary mechanism responsible for changes in cardiac output during activation of the carotid sinus baroreflex.

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Clarysse, I., und M. Demedts. „Human esophageal pressures and chest wall configuration in upright and head-down posture“. Journal of Applied Physiology 59, Nr. 2 (01.08.1985): 401–7. http://dx.doi.org/10.1152/jappl.1985.59.2.401.

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Pressures were measured at two levels in the esophagus in 14 young healthy subjects performing slow inspiratory and expiratory vital capacity (VC) maneuvers in upright and head-down posture (180 degrees body tilt). In both postures, a gravitational pressure gradient was found, which increased very slightly with decreasing lung volumes (0.006 cmH2O X % VC-1 X cm descent-1) except for upright expiratory curves above 60% VC. The expiratory pressure gradient tended to be larger in head-down than in upright posture; however, during inspiration the opposite was true. In both postures the pressure change between 100 and 20% VC was smaller in the uppermost zone, which is consistent with the smaller changes in alveolar expansion in this zone. Also, in seven of the subjects, changes in cross-sectional area of the middle and lower part of the rib cage (HRC and LRC) and of the abdomen (ABD) were measured by respiratory inductive plethysmography in upright and head-down posture. The ratio of HRC motion to LRC motion was constant throughout the VC and did not change with posture, yet the ratio of ABD motion to mean RC motion changed with overall volume and was also larger in head-down than in upright posture. In conclusion, the changes in esophageal pressure gradient during slow VC maneuvers in head-down vs. upright posture were not related to (and thus not caused by) changes in chest wall configuration.

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Stevenson, William B. „Change in the Structure of Bureaucracy“. Sociological Perspectives 29, Nr. 3 (Juli 1986): 307–36. http://dx.doi.org/10.2307/1389023.

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The impact of pressures for change over time in three city government bureaucracies is analyzed, and the cities are found to accommodate demands for change by adding structural units and not hiring additional employees. It is suggested that managers respond to pressures for change by adding structures, regardless of increases in administrative cost and complexity, because bureaucratic structure is the legitimate, socially prescribed vehicle to accomplish bureaucratic goals. This implies that attempts at major changes in public bureaucracies may lead to more bureaucratic structure and increased costs of administration.

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Smith, Matthew E., und James R. Tysome. „Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty“. Otolaryngology–Head and Neck Surgery 156, Nr. 1 (11.10.2016): 161–65. http://dx.doi.org/10.1177/0194599816672842.

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Objective Balloon eustachian tuboplasty (BET) has entered clinical use as a treatment for eustachian tube dysfunction. Some surgeons perform myringotomy prior to BET due to concerns that the increase in middle ear (ME) pressure caused by BET may cause otic barotrauma. We investigated the ME pressure changes occurring during BET in cadavers. Study design Human cadaver investigation of a surgical technique Setting Laboratory study at a tertiary referral center. Subjects and Methods ME pressures were recorded from fresh-frozen cadavers, and BET was performed with the Bielefeld balloon catheter inflated to 10 bar. Peak ME pressures were recorded during catheter insertion, inflation, deflation, and removal. A second pressure measurement was taken 15 seconds after each stage to assess the residual pressures. All BET procedures were repeated at least once. Where transmastoid recordings were made, BET was repeated, measuring pressure via a myringotomy to ensure equivalence. Results Data from 25 procedures in 13 ears (9 heads) were analyzed. A consistent pattern of ME pressure change was observed in all cases. Positive pressures occurred on insertion (maximum, 26 daPa) and inflation (maximum, 99 daPa) and negative pressures on deflation (maximum, –46 daPa) and removal (maximum, –42 daPa). There were no significant pressure differences between first and second procedures, except at 15 seconds after insertion ( P = .04). Conclusion In adult cadaveric specimens, BET induces ME pressures within the normal physiologic range. On this basis, routine myringotomy prior to BET in adults is not necessary.

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Zarrati, A. R., Yee-Chung Jin, A. Shanehsaz-zadeh und F. Ahadi. „Potential flow solution for a free surface flow past a sudden slope change“. Canadian Journal of Civil Engineering 31, Nr. 4 (01.08.2004): 553–60. http://dx.doi.org/10.1139/l04-021.

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An analytical model was developed to calculate the pressure distribution in a free surface flow past a sudden change in channel slope. A conformal transformation technique was used to solve the problem analytically in a way that there is no need for trial and error to find the location of the free surface. Two methods were employed for this simulation: flow at a corner and free streamline theory. It was shown that free streamline theory is more accurate. Experiments were conducted to verify the ability of the analytical model to calculate the pressure distribution in a channel with a sudden change in slope. Slope changes of 6.22°, 10°, and 15° were tested with various flow discharges. The analytical model predictions of pressure distribution along the channel bed and with depth agreed well with the experimental measurements. Pressures up to 25 times the hydrostatic pressure were experimentally measured near the point of sudden change in slope. These pressures were reproduced by the model. The analytical model predictions of the water surface profile over a ramp in a prototype spillway were compared with those of a numerical model. The comparison showed a good agreement.Key words: pressure distribution, free surface flow, analytical model, chute spillway, aerator ramp, potential flow.

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Tatko, Radosław, und Sylwester Kobielak. „Horizontal Bulk Material Pressure in Silo Subjected to Impulsive Load“. Shock and Vibration 15, Nr. 5 (2008): 543–50. http://dx.doi.org/10.1155/2008/289317.

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This paper describes laboratory tests carried out in the steel flat-bottomed silo model filled with sand, subjected to external dynamic loads. The model was placed on a system of springs, which represent subsoil. The loads in the form of horizontal impulses were applied to the bottom plate of the silo. Horizontal pressure-time courses were used to analyze the influence of subsoil vibrations on the distribution changes of these pressures. Basic conclusion: (1) the subsoil vibrations cause two types of changes of the horizontal pressures: stable changes which are observed when the model vibrations finish and cyclic of short duration (brief) changes; (2) the subsoil vibrations either generate stable increase or stable decrease of the pressures from before vibrations or do not generate any essential stable change; (3) the cyclic dynamic changes of the horizontal pressures depend on the direction of the silo wall displacements and they are the function of the values of these displacements.

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Wang, Lixiang, Weian Li und Lujun Qi. „Stakeholder Pressures and Corporate Environmental Strategies: A Meta-Analysis“. Sustainability 12, Nr. 3 (06.02.2020): 1172. http://dx.doi.org/10.3390/su12031172.

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Stakeholder pressures and corporate environmental strategies continue to be important topics of corporate sustainability. Limited by sample size, there is a lack of general conclusions on which groups of stakeholder pressures are the main drivers of environmental strategies. Amassing a database of 58 empirical studies, the authors divided stakeholder pressures into four groups—internal, coercive, market, and social pressure—and explored the relationship between different pressures and environmental strategies by conducting a meta-analysis. The main result shows that internal pressure is the main driver of environmental strategies. Further empirical results show that stakeholder pressures could have a larger effect on corporate environmental strategies in developed countries and that non-manufacturing firms could change their environmental strategies more easily than manufacturing firms. The results provide the practical implication that a green industry transition is strongly needed in the manufacturing industry, especially for polluting industries, and that firms in polluting industries should implement environmental strategy changes in the future. This paper contributes to clarifying the relationship between stakeholder pressures and corporate environmental strategies based on a meta-analysis.

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Stühmer, Walter. „Exocytosis from chromaffin cells: hydrostatic pressure slows vesicle fusion“. Philosophical Transactions of the Royal Society B: Biological Sciences 370, Nr. 1672 (05.07.2015): 20140192. http://dx.doi.org/10.1098/rstb.2014.0192.

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Pressure affects reaction kinetics because chemical transitions involve changes in volume, and therefore pressure is a standard thermodynamic parameter to measure these volume changes. Many organisms live in environments at external pressures other than one atmosphere (0.1 MPa). Marine animals have adapted to live at depths of over 7000 m (at pressures over 70 MPa), and microorganisms living in trenches at over 110 MPa have been retrieved. Here, kinetic changes in secretion from chromaffin cells, measured as capacitance changes using the patch-clamp technique at pressures of up to 20 MPa are presented. It is known that these high pressures drastically slow down physiological functions. High hydrostatic pressure also affects the kinetics of ion channel gating and the amount of current carried by them, and it drastically slows down synaptic transmission. The results presented here indicate a similar change in volume (activation volume) of 390 ± 57 Å 3 for large dense-core vesicles undergoing fusion in chromaffin cells and for degranulation of mast cells. It is significantly larger than activation volumes of voltage-gated ion channels in chromaffin cells. This information will be useful in finding possible protein conformational changes during the reactions involved in vesicle fusion and in testing possible molecular dynamic models of secretory processes.

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Barnett, Steven. „Media ownership policies: Pressures for change and implications“. Pacific Journalism Review : Te Koakoa 10, Nr. 2 (01.09.2004): 8–19. http://dx.doi.org/10.24135/pjr.v10i2.801.

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We are witnessing a wholesale restructuring of media ownership statutes throughout the world. It is difficult to think of a single developed or developing country which over the last 10 years has not introduced at least one change – and in many cases more – in its media ownership regimes. The direction is almost entirely one-way: towards a more liberal and deregulated environment which allows for more conglomeration of media companies, greater flexibility in foreign ownership, and fewer restrictions on ownership across different media. I want to address two important aspects of this worldwide phenomenon: first, why it is happening and the main forces driving these changes; and second, the implications for a free press, for diversity, and for journalism.

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Reid, Ian G. „Pressures for change in the Common Agricultural Policy“. Proceedings of the Nutrition Society 44, Nr. 3 (September 1985): 399–408. http://dx.doi.org/10.1079/pns19850065.

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Zhang, F. X., B. Manoun, S. K. Saxena und C. S. Zha. „Structure change of pyrochlore Sm2Ti2O7 at high pressures“. Applied Physics Letters 86, Nr. 18 (02.05.2005): 181906. http://dx.doi.org/10.1063/1.1925307.

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Cadez, Simon, Albert Czerny und Peter Letmathe. „Stakeholder pressures and corporate climate change mitigation strategies“. Business Strategy and the Environment 28, Nr. 1 (03.05.2018): 1–14. http://dx.doi.org/10.1002/bse.2070.

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Slack, Trevor, und Bob Hinings. „Institutional Pressures and Isomorphic Change: An Empirical Test“. Organization Studies 15, Nr. 6 (November 1994): 803–27. http://dx.doi.org/10.1177/017084069401500602.

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Ye, Z., und A. M. Birk. „Fluid Pressures in Partially Liquid-Filled Horizontal Cylindrical Vessels Undergoing Impact Acceleration“. Journal of Pressure Vessel Technology 116, Nr. 4 (01.11.1994): 449–58. http://dx.doi.org/10.1115/1.2929615.

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An experimental investigation has been carried out to study the fluid pressures in partially liquid-filled vessels when they are suddenly accelerated by impact along the longitudinal axis. The experiments were conducted with three horizontal cylindrical tanks of different length-to-diameter ratios of L/D = 6.0, 3.5, 2.0. The tanks were filled with water at ambient pressure and temperature and were accelerated using a large steel impact hammer. Internal tank wall pressures caused by the acceleration were measured with transient pressure transducers. Six types of pressure-time histories have been observed and results indicated that the pressure profile changes with fill level and transducer location. The peak pressures on the end of the tank are strongly affected by the fill level and the tank length-to-diameter ratio L/D. A modal change in the behavior of liquid movement has been found around fill level h/D = 0.95. For fill levels h/D above 0.95, the pressure in the tanks acted like either a water hammer or an accelerated fluid column, depending on the duration of the impact relative to the pressure wave transit time. For the fill levels with h/D below 0.95, liquid sloshing activity was involved and the pressure at the end of the tank was a function of the liquid dynamic pressure. This modal change also caused the location of maximum peak pressure to move from the impact end of the tank to the tank top. In some cases the pressure on the tank top was two times larger than that at the tank impact end. The maximum pressure observed from the tests was on the top of the tank. This modal change may have some significance in some transportation applications.

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Wick, Cheryl, Uwe Nienaber, Olga Anggraeni, Thomas H. Shellhammer und Polly D. Courtney. „Texture, proteolysis and viable lactic acid bacteria in commercial Cheddar cheeses treated with high pressure“. Journal of Dairy Research 71, Nr. 1 (Februar 2004): 107–15. http://dx.doi.org/10.1017/s0022029903006587.

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High pressure processing was investigated for controlling Cheddar cheese ripening. One-month- or 4-month-old Cheddar cheeses were subjected to pressures ranging from 200 to 800 MPa for 5 min at 25 °C. The number of viable Lactococcus lactis (starter) and Lactobacillus (nonstarter) cells decreased as pressure increased. Subsequent storage of the control and pressure-treated cheeses at 10 °C caused viable cell counts to change in some cases. Free amino acid content was monitored as an indicator of proteolysis. Cheeses treated with pressures [ges ]400 MPa evolved free amino acids at significantly lower rates than the control. No acceleration in free amino acid development was observed at lower pressures. Pressure treatment did not accelerate the rate of textural breakdown compared with the non-pressure treated control. On the contrary, pressure treatment at 800 MPa reduced the time-dependent texture changes. Results indicate that high pressure may be useful in arresting Cheddar cheese ripening.

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Fike, C. D., und M. R. Kaplowitz. „Effect of chronic hypoxia on pulmonary vascular pressures in isolated lungs of newborn pigs“. Journal of Applied Physiology 77, Nr. 6 (01.12.1994): 2853–62. http://dx.doi.org/10.1152/jappl.1994.77.6.2853.

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Our purposes were to determine whether chronic alveolar hypoxia altered pulmonary vascular pressures in lungs of newborn pigs, evaluate the contribution of smooth muscle tone to alterations in pulmonary vascular pressures, and examine whether chronic hypoxia altered pulmonary vascular reactivity to acute hypoxia. We kept 24- to 72-h-old pigs in chambers filled with room air (control) or 11–12% O2 (chronic hypoxia) for either 3–5 (short) or 10–12 (long) days. We used isolated lungs and applied micropuncture and vascular occlusion techniques to measure pressure in 10- to 30-microns-diam venules and inflow occlusion and outflow occlusion pressures before and after the addition of the smooth muscle dilator papaverine or before and after inflation of the lungs with a hypoxic gas mixture. For pigs in both the short and long groups, pulmonary arterial pressure was the only vascular pressure that was greater in chronically hypoxic than in control lungs. Increased smooth muscle tone was the primary source of the change in pulmonary arterial pressure with short hypoxia, whereas morphometric changes contributed to the change in pulmonary arterial pressure with long hypoxia. Exposure of newborn pigs to different lengths of alveolar hypoxia is a useful model to study postnatal pulmonary hypertension in newborns and infants.

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Rahardjo, Harianto, und Delwyn G. Fredlund. „Experimental verification of the theory of consolidation for unsaturated soils“. Canadian Geotechnical Journal 32, Nr. 5 (01.10.1995): 749–66. http://dx.doi.org/10.1139/t95-074.

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An experimental program was designed to study the behavior of unsaturated soils during undrained loading and consolidation. A Ko cylinder was designed and built for the testing program. Simultaneous measurements of pore-air and pore-water pressures could be made throughout a soil specimen using this Ko cylinder. Four types of tests were performed on a silty sand. These are (1) undrained loading tests where both the air and water are not allowed to drain, (2) constant water content tests where only the water phase is not allowed to drain, (3) consolidation tests where both the air and water phases are allowed to drain, and (4) increasing matric suction tests. Undrained loading tests or constant water content loading tests were conducted for measuring the pore pressure parameters for the unsaturated soil. Drained tests consisting of either consolidation tests or increasing matric suction tests were conducted to study the pore pressure distribution and volume change behavior throughout an unsaturated soil during a transient process. The experimental pore pressure parameters obtained from the undrained loadings and constant water content leadings agreed reasonably well with theory. The pore-air pressure was found to dissipate instantaneously when the air phase is continuous. The pore-water pressure dissipation during the consolidation test was found to be faster than the pore-water pressure decrease during the increasing matric suction test. The differing rates of dissipation were attributed to the different coefficients of water volume change for each of the tests. The water volume changes during the consolidation test were considerably smaller than the water volume changes during the increasing matric suction tests for the same increment of pressure change. Key words : consolidation, Ko loading, matric suction, pore-air pressures, pore-water pressures, unsaturated soils

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Bouraï, Liess, Maxime Logez, Christophe Laplace-Treyture und Christine Argillier. „How Do Eutrophication and Temperature Interact to Shape the Community Structures of Phytoplankton and Fish in Lakes?“ Water 12, Nr. 3 (11.03.2020): 779. http://dx.doi.org/10.3390/w12030779.

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Freshwater ecosystems are among the systems most threatened and impacted by anthropogenic activities, but there is still a lack of knowledge on how this multi-pressure environment impacts aquatic communities in situ. In Europe, nutrient enrichment and temperature increase due to global change were identified as the two main pressures on lakes. Therefore, we investigated how the interaction of these two pressures impacts the community structure of the two extreme components of lake food webs: phytoplankton and fish. We modelled the relationship between community components (abundance, composition, size) and environmental conditions, including these two pressures. Different patterns of response were highlighted. Four metrics responded to only one pressure and one metric to the additive effect of the two pressures. Two fish metrics (average body-size and biomass ratio between perch and roach) were impacted by the interaction of temperature and eutrophication, revealing that the effect of one pressure was dependent on the magnitude of the second pressure. From a management point of view, it appears necessary to consider the type and strength of the interactions between pressures when assessing the sensitivity of communities, otherwise their vulnerability (especially to global change) could be poorly estimated.

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Charalambous, C., T. A. Barker, C. S. Zipitis, I. Siddique, R. Swindell, R. Jackson und J. Benson. „Comparison of Peripheral and Central Venous Pressures in Critically Ill Patients“. Anaesthesia and Intensive Care 31, Nr. 1 (Februar 2003): 34–39. http://dx.doi.org/10.1177/0310057x0303100106.

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We conducted a prospective study to determine the relationship between central (CVP) and peripheral (PVP) venous pressures in critically ill patients. CVP and PVP were measured on five different occasions in 20 critically ill patients in the intensive care unit. Results showed that the mean difference between PVP and CVP was 4.4 mmHg (95% CI= 3.7 to 5.0). However, PVP might be 1.9 mmHg below (95% CI=0.7 to 3.1) or 10.6 mmHg above (95% CI=9.4 to 11.8) the CVP. The mean difference between changes in PVP and corresponding changes in CVP was 0.3 mmHg (95%CI=-0.1 to 0.7). The actual change in PVP could be 3.0 mmHg below (95% CI=2.3 to 3.7) or 3.6 mmHg above (95% CI=2.9 to 4.3) the change in CVP. Overall, the direction of change in PVP (rise or drop) predicted a same direction of change in CVP with an accuracy of 78%. Changes in PVP ≥2 mmHg predicted a change in same direction of CVP with an accuracy of 90%. The direction of changes in CVP ≥2 mmHg were predicted by the direction of change in PVP with an accuracy of 91%. We conclude that PVP measurement does not give an accurate estimate of the absolute value of CVP in individual patients. However, as changes in PVP parallel, in direction, changes in CVP, serial measurements of PVP may have a value in determining volume status and guiding fluid therapy in critically ill patients.

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