bluuebunny/crossref_metadata_2025_split huggingface dataset:
β‐Adrenergic blockade in the dentate gyrus in vivo prevents high frequency‐induced long‐term potentiation of EPSP slope, but not long‐term potentiation of population spike amplitude
Authors: Munro Catherine A.M. , Walling Susan G. , Evans John H. , Harley Carolyn W. 
Published: August 2002

AbstractHigh frequency (HF)‐induced and norepinephrine (NE)‐induced long‐term potentiation have been hypothesized to utilize common mechanisms of induction and expression in the dentate gyrus. In vitro data tend to support this hypothesis, but few studies have been done in vivo. The present study records perforant path‐evoked potentials simultaneously on two micropipettes, one filled with saline and the other with the β‐antagonist, timolol. Stimulation of the paragigantocellularis nucleus (PGi) was used as a method of producing NE release in the dentate gyrus, and thus, to assess the efficacy of β‐receptor blockade on the timolol pipette. β‐blockade by timolol attenuated PGi‐induced spike potentiation. HF‐induced potentiation of the excitatory post‐synaptic potential (EPSP) slope was also blocked by timolol, but HF‐induced spike amplitude potentiation was unaffected. These results are consistent with an earlier report examining HF‐long‐term potentiation (LTP) following 6‐OHDA‐induced NE depletion, which showed that the EPSP slope LTP depended, for its full expression, on NE, but potentiation of the population spike amplitude component of HF‐induced LTP did not. In the present study, PGi‐induced potentiation of spike amplitude on the saline pipette was normal after HF‐induced saturation of spike amplitude potentiation, suggesting that the mechanisms for expression of spike potentiation, as well as induction of spike potentiation, are separate for HF and NE stimulation. Hippocampus 2001;11:322–328. © 2001 Wiley‐Liss, Inc.
Improvement of the basic correlating equations and transition criteria of natural convection heat transfer
Authors: Yang Shi‐Ming 
Published: August 2002

AbstractIn this paper, improvements in the basic physical laws of natural convection heat transfer were implemented in two major respects by incorporating recent research findings in this field. A preferred transition criterion was adopted in this paper to correlate all of the experimental data. Since transition correlations are primarily flow stability problems, the Grashof number, instead of the Rayleigh number, was found to be the preferred criterion. Furthermore, in the case of natural convection heat transfer from a horizontal cylinder, a series of experimental data in the high‐Rayleigh‐number regions recently became available. These data made it possible to establish new reliable correlations and also to test the validity of previous correlations. It is concluded that the previous correlation for a horizontal cylinder in high‐Rayleigh‐number regions was based on unreliable experimental results. The transition correlation for a horizontal cylinder occurred at much higher values of Rayleigh number than the previous recommendation. In the case of natural convection heat transfer from a vertical plate, more accurate property values for air under pressurized conditions are now available. This made it possible to replot the reliable data of Saunders. From this result and the experimental result of Warner and Arpaci, a new set of basic correlations in natural convection heat transfer for laminar, transitional, and turbulent regimes are recommended. These recommendations reflect a better understanding of the basic physical laws in the field of heat convection. © 2001 Scripta Technica, Heat Trans Asian Res, 30(4): 293–300, 2001
Subjective ratings of prospective memory deficits in MDMA (‘ecstasy’) users
Authors: Heffernan Thomas M. , Ling Jonathon , Scholey Andrew B. 
Published: August 2002

AbstractChronic use of MDMA (3,4‐methylenedioxymethamphetamine), or ‘ecstasy’, is associated with significant cognitive impairments, particularly in laboratory and field tests of memory for previously encoded material. Less is known about the effects of a history of MDMA use on aspects of everyday cognitive functioning–of which prospective memory (typically characterised as ‘remembering to do something at some future point’) is an important aspect. Self‐ratings of prospective memory among 30 regular ecstasy users (taking the drug 10 or more times per month) and 31 ecstasy‐free controls were compared. Each participant completed the Prospective Memory Questionnaire, which measures self‐rated error frequencies relating to three aspects of prospective memory (short‐term habitual, long‐term episodic and internally cued); the scale also records the use of strategies to aid remembering. Compared with non‐users, ecstasy users reported significantly more self‐rated errors in prospective memory, an effect which was evident after co‐varying levels of other drug use. There were no significant differences in the use of strategies to aid memory. These findings provide new insights into prospective memory dysfunction in recreational drug users. Prospective memory deficits may be related to the reported serotonergic and frontal lobe deficits in chronic MDMA users. It is necessary to use more objective tasks to assess putative prospective memory deficits in ecstasy users. Copyright © 2001 John Wiley & Sons, Ltd.
Evaluating explicit and implicit routing for watershed hydro‐ecological models of forest hydrology at the small catchment scale
Authors: Tague C. L. , Band L. E. 
Published: August 2002

AbstractThis paper explores the behaviour and sensitivity of a watershed model used for simulating lateral soil water redistribution and runoff production. In applications such as modelling the effects of land‐use change in small headwater catchments, interactions between soil moisture, runoff and ecological processes are important. Because climate, soil and canopy characteristics are spatially variable, both the pattern of soil moisture and the associated outflow must be represented in modelling these processes. This study compares implicit and explicit routing approaches to modelling the evolution of soil moisture pattern and spatially variable runoff production. It also addresses the implications of using different landscape partitioning strategies. This study presents the results of calibration and application of these different routing and landscape partitioning approaches on a 60 ha forested watershed in Western Oregon. For comparison, the different approaches are incorporated into a physically based hydro‐ecological model, RHESSys, and the resulting simulated soil moisture, runoff production and sensitivity to unbiased error are examined. Results illustrate that both routing approaches can be calibrated to achieve a reasonable fit between observed and modelled outflow. Calibrated values for effective watershed hydraulic conductivity are higher for the explicit routing approach, which illustrates differences between the two routing approaches in their representation of internal watershed dynamics. The explicit approach illustrates a seasonal shift in drainage organization from watershed to more local control as climate goes from a winter wet to a summer dry period. Assumptions used in the implicit approach maintain the same pattern of drainage organization throughout the season. The implicit approach is also more sensitive to random error in soil and topographic input information, particularly during wetter periods. Comparison between the two routing approaches illustrates the advantage of the explicit routing approach, although the loss of computational efficiency associated with the explicit routing approach is noted. To compare different strategies for partitioning the landscape, the use of a non‐grid‐based method of partitioning is introduced and shown to be comparable to grid‐based partitioning in terms of simulated soil moisture and runoff production. Copyright © 2001 John Wiley & Sons, Ltd.
On the information content of forest transpiration measurements for identifying canopy conductance model parameters
Authors: Dekker S. C. , Bouten W. , Bosveld F. C. 
Published: August 2002

AbstractGenerally, forest transpiration models contain model parameters that cannot be measured independently and therefore are tuned to fit the model results to measurements. Only unique parameter estimates with high accuracy can be used for extrapolation in time or space. However, parameter identification problems may occur as a result of the properties of the data set. Time‐series of environmental conditions, which control the forest transpiration, may contain periods with redundant or coupled information, so called collinearity, and other combinations of conditions may be measured only with difficulty or incompletely. The aim of this study is to select environmental conditions that yield a unique parameter set of a canopy conductance model. The parameter identification method based on localization of information (PIMLI) was used to calculate the information content of every individual artificial transpiration measurement. It is concluded that every measurement has its own information with respect to a parameter. Independent criteria were assessed to localize the environmental conditions, which contain measurements with most information. These measurements were used in separate subdata sets to identify the parameters. The selected measurements do not overlap and the accuracies of the parameter estimates are maximized. Measurements that were not selected do not contain additional information that can be used to further maximize the parameter accuracy. Thereupon, the independent criteria were used to select eddy correlation measurements and parameters were identified with only the selected measurements. It is concluded that, for this forest and data set, PIMLI identifies a unique parameter set with high accuracy, whereas conventional calibrations on subdata sets give non‐unique parameter estimates. Copyright © 2001 John Wiley & Sons, Ltd.
A simple model of river meandering and its comparison to natural channels
Authors: Lancaster Stephen T. , Bras Rafael L. 
Published: August 2002

AbstractWe develop a new method for analysis of meandering channels based on planform sinuosity. This analysis objectively identifies three channel‐reach lengths based on sinuosity measured at those lengths: the length of typical, simple bends; the length of long, often compound bends; and the length of several bends in sequence that often evolve from compound bends to form multibend loops. These lengths, when normalized by channel width, tend to fall into distinct and clustered ranges for different natural channels. Mean sinuosity at these lengths also falls into distinct ranges. That range is largest for the third and greatest length, indicating that, for some streams, multibend loops are important for planform sinuosity, whereas for other streams, multibend loops are less important. The role of multibend loops is seldom addressed in the literature, and they are not well predicted by previous modelling efforts. Also neglected by previous modelling efforts is bank–flow interaction and its role in meander evolution. We introduce a simple river meandering model based on topographic steering that has more in common with cellular approaches to channel braiding and landscape evolution modelling than to rigorous, physics‐based analyses of river meandering. The model is sufficient to produce reasonable meandering channel evolution and predicts compound bend and multibend loop formation similar to that observed in nature, in both mechanism and importance for planform sinuosity. In the model, the tendency to form compound bends is sensitive to the relative magnitudes of two lengths governing meander evolution: (i) the distance between the bend cross‐over and the zone of maximum bank shear stress, and (ii) the bank shear stress dissipation length related to bank roughness. In our simple model, the two lengths are independent. This sensitivity implies that the tendency for natural channels to form compound bends may be greater when the banks are smoother. Copyright © 2002 John Wiley & Sons, Ltd.
The hydrology of the upper Swan River Estuary with focus on an artificial destratification trial
Authors: Hamilton David P. , Chan Terence , Robb Malcolm S. , Pattiaratchi Chari B. , Herzfeld Michael 
Published: August 2002

AbstractA trial to artificially destratify part of the water column of the Swan–Canning Estuary took place over four weeks in 1997. Destratification was attempted with bubble plumes created by pumping compressed air through a porous pipe near the bed at a location in the upper estuary. The purpose of the trial was to determine whether the resultant bubble ‘curtain’ could mix the water column, thereby altering the extent of upstream and downstream mixing and the vertical structures of salinity, temperature, dissolved oxygen and turbidity. The destratification trial was monitored using three techniques: vertical profiles taken on several days at selected stations along the estuary, fine scale profiles in the vicinity of the bubble curtain on one day, and continuous water column profiles taken 1 km upstream of the curtain. The seasonal upstream propagation of brackish water underneath a residual freshwater discharge was affected by the magnitude of freshwater discharge and tidal elevations. Superimposed upon diurnal and semi‐diurnal tides were non‐tidal water level changes induced mostly by variations in barometric pressure. These caused large changes in the salt wedge position. Destratification by the bubble curtain was compromised by these large oscillations, which limited the exposure of the salt wedge region to the mixing action of the bubble curtain. Complete vertical mixing of the water column was observed up to 30 m either side of the curtain on 30 October. Disruptions to the density stratification were not evident beyond 350 m of the curtain. In the immediate vicinity (∼30 m) of the curtain, deficits of dissolved oxygen in bottom waters were generally reduced or obliterated and a naturally turbid plume of water near the bottom of the estuary was mixed through the water column. The effects of the bubble curtain on dissolved oxygen, turbidity and temperature were, however, similar to those for salinity, with mixing confined to around 30 m from the curtain and no effect observed further than 350 m away. The upper Swan River estuary, although relatively narrow and strongly vertically stratified, is unsuited to destratification using bubble plumes. Cycling of spring and neap tides and non‐tidal water level changes, together with freshwater inflows to the estuary, strongly limit the longitudinal extent of mixing by bubble curtains. Copyright © 2001 John Wiley & Sons, Ltd.
Observational data and scale‐dependent parameterizations: explorations using a virtual hydrological reality
Authors: Bashford Kathy E. , Beven Keith J. , Young Peter C. 
Published: August 2002

AbstractThe use of small‐scale process descriptions at larger scales has been identified as a major problem in hydrological modelling. An alternative is to use measurements taken at a larger scale, such as remote sensing data, and to develop process descriptions at that scale.A hypothetical catchment area, or ‘virtual hydrological reality’ dataset has been generated to explore the value of different types of data in model structure and parameter identification. Though only an approximation to the natural responses of the catchment, this virtual reality can be used to explore the use of observational series that would not normally be available.A data‐based mechanistic approach was used to model evapotranspiration from 1 km data, as though they were available from remote sensing. The resulting parameterization is of a similar form to an evaporative fraction model. It is an example of the type of parameterization that could be used to describe the land surface, without estimation of effective parameters from small‐scale measurements, and avoiding overparameterization. Copyright © 2002 John Wiley & Sons, Ltd.
Peculiarities of ice events in Russian Arctic rivers
Authors: Vuglinsky V. S. 
Published: August 2002

AbstractThe state‐of‐the‐art of the hydrological network for the study of river‐ice regimes in the Russian Arctic is reviewed as well as the regularly published documents that characterize specific features of ice events. The dates of the beginning of different ice events (e.g. ice drift, ice‐cover formation, frazil ice drift, etc.) are analysed as well as the duration of such events for 16 rivers typical of the Russian Arctic. It is demonstrated that ice on Arctic rivers of Asian Russia forms earlier and breaks up later compared to those of European Russia; this is explained by the more severe climate conditions that affect the northern areas of Siberia. Ice‐cover duration on the study rivers varies from 140 to 250 days with the maximum duration being observed in the lower reaches of large rivers in East Siberia and the Far East. Ice‐cover duration and the latitude of the observation stations are strongly correlated. The dynamics of ice‐cover growth and melting on rivers, ice thickness and snow‐pack depth on the ice are considered in different parts of the Russian Arctic. It is demonstrated that the nature of ice growth during the autumn–winter period and its decrease in spring mainly depend on the thermal conditions during a particular year. In years with low air temperatures, ice‐cover thickness in the rivers of the Far East can attain 200 cm and greater, meanwhile it may be 50 or 60 cm only in the rivers of European Russia if the winter is warm. Particular case studies are given to illustrate these features. Copyright © 2002 John Wiley & Sons, Ltd.
The effects of log erosion barriers on post‐fire hydrologic response and sediment yield in small forested watersheds, southern California
Authors: Wohlgemuth Peter M. , Hubbert Ken R. , Robichaud Peter R. 
Published: August 2002

AbstractWildfire usually promotes flooding and accelerated erosion in upland watersheds. In the summer of 1999, a high‐severity wildfire burned a series of mixed pine/oak headwater catchments in the San Jacinto Mountains of southern California. Log erosion barriers (LEBs) were constructed across much of the burned area as an erosion control measure. We built debris basins in two watersheds, each about 1 ha in area, one with LEBs, the other without, to measure post‐fire hydrologic response and sediment yield and to evaluate the effectiveness of the LEBs. The watersheds are underlain by granitic bedrock, producing a loamy sand soil above large extents of weathered bedrock and exposed core stones (tors) on the surface. Measured soil water‐repellency was similar over the two catchments. Rain gauges measured 348 mm of precipitation in the first post‐fire year. The ephemeral stream channels experienced surface flow after major rainstorms, and the source of the water was throughflow exfiltration at the slope/channel interface. Post‐fire overland flow produced some rilling, but hillslope erosion measured in silt fences away from any LEBs was minor, as was sediment accumulation behind the LEBs. Stream channels in the catchments exhibited minor net scour. Water yield was much greater in the LEB‐treated watershed. This resulted in 14 times more sediment yield by weight than the untreated watershed. Average soil depths determined by augering were nearly double in the catchment without the LEBs compared with the treated watershed. This suggests that differences in water and sediment yield between the two catchments are due to the twofold difference in the estimated soil water‐holding capacity in the untreated watershed. It appears that the deeper soils in the untreated watershed were able to retain most of the precipitation, releasing less water to the channels and thereby reducing erosion and sediment yield. Thus, the test of LEB effectiveness was inconclusive in this study, because soil depth and soil water‐holding capacity may have masked their performance. Published in 2001 John Wiley & Sons, Ltd.
Farnesyl thiosalicylic acid inhibits the growth of melanoma cells through a combination of cytostatic and pro‐apoptotic effects
Authors: Smalley Keiran S.M. , Eisen Tim G. 
Published: August 2002

AbstractNovel classes of drug that interfere with the signalling of the small G‐protein Ras, the so‐called Ras antagonists, are showing much promise as novel anti‐cancer agents. In this study, we demonstrate that the novel Ras antagonist farnesylthiosalicylic acid (FTS) inhibits the growth of Colo 853 melanoma cells through a combination of cytostatic and pro‐apoptotic effects. Furthermore, these phenomena are seen under conditions of cell attachment and in the presence of serum. Treatment of Colo 853 cells with FTS led to time‐dependent inhibition of constitutive Akt, retinoblastoma protein (pRB) and ERK activity, with a concurrent loss of Akt expression. Inhibition of Akt and ERK activity induces apoptosis in other human cancer cell lines. Here it is demonstrated that inhibition of Akt, or ERK and Akt in combination, leads to cell cycle arrest but not apoptosis in melanoma cells. FTS treatment was also found to upregulate activity of the stress‐activated p38 MAP kinase. Inhibition of p38 MAP kinase, using the selective inhibitor SB 203580, followed by FTS treatment, significantly increased the proportion of apoptotic cells after 72 hr, possibly suggesting a modulatory role for p38 MAP kinase in FTS‐induced melanoma cell apoptosis. © 2002 Wiley‐Liss, Inc.
Breast cancer risk factors and age at diagnosis: An Icelandic cohort study
Authors: Tryggvadóttir Laufey , Tulinius Hrafn , Eyfjord Jórunn E. , Sigurvinsson Trausti 
Published: August 2002

AbstractAn increasing number of studies indicates that the strength and even direction of association between breast cancer and established risk factors differ according to the woman's age when she develops the disease. This was studied in the setting of a population based cancer registry using a databank with information on age at menarche, parity, age at first birth, oral contraceptive (OC) use, lactation, height and weight. From a cohort of 80.219 women attending population‐based cervical and breast cancer screening in Iceland, 1120 cases were identified, aged 26–90 years at diagnosis and 10,537 controls, individually matched to the cases on birth year and age when attending. Information given at last visit before diagnosis was used in the analysis, applying conditional logistic regression. Odds ratios and statistical strength of relationships varied according to age at diagnosis for age at first birth, number of births, duration of lactation, height and weight. The decreased risk associated with young age at first birth and increasing duration of breast feeding became less pronounced with advancing age at diagnosis. A reduced risk associated with an increasing number of births was not detected in women diagnosed under the age of 40. An increased risk associated with giving first birth after 30 years of age was mainly detected in women who had only given 1 birth and were diagnosed under the age of 40 (OR = 7.06 95% CI = 2.16–23.01). A positive association with height and especially with weight was confined to women diagnosed after the age of 55. The results confirm that age at diagnosis should be taken into account when studying the effects of breast cancer risk factors. © 2002 Wiley‐Liss, Inc.