Variation In Discharge Rates Research Articles

Performance assessment of valve regulated lead acid battery for E–bike in field test

The Performance of Valve Regulated Lead Acid battery in E–the bike is affected by various operational and topographical parameters like operating temperatures, variation in discharge rates of the vehicle, operation of the vehicle at the different State of Charge, etc. In this paper, performance of the Valve Regulated Lead Acid batteries of E-bike is evaluated under different driving cycles with various road conditions and climatic conditions. All the driving processes are dividing according to routes, i.e., urban route, gradient route, highway route, rural route, and time of the day, i.e., morning, afternoon, and evening. All the experiments are performed with old and new battery set for a thorough study of the performance of batteries with the different States of Heath. The OREVA ALISH E-bike equipped with four numbers of 12 V, 25 Ah Valve Regulated Lead Acid batteries is selected for experimentation. The experimental analysis revealed that the climatic conditions, the topology of the region and the State of Health significantly affect the battery temperature during operating conditions. The results show that a battery temperature increases rapidly during afternoon field tests, going up to 45.4˚C when the ambient temperature is 39.7˚C. The route pattern significantly affects the energy consumption of E-bike also. The highest energy consumption of 15.05 Wh/km is observed on the gradient route.

Formation, evolution, and drainage of short-lived glacial lakes in permafrost environments of the northern Teskey Range, Central Asia

Abstract. In the Teskey Range of the Tien Shan (Kyrgyz Republic), five outburst flood disasters from short-lived glacial lakes in 2006, 2008, 2013, 2014, and 2019 caused severe damages in the downstream part. Short-lived glacial lakes in the Teskey Range grow rapidly and drain within a few months, due to closure and opening of an outlet ice tunnel in an ice-cored moraine complex at the glacier front. In addition to these factors, summer meltwater from the glacier can cause rapid growth. Outburst floods of this lake type are a major hazard in this region and differ from the moraine-dam failures common to the eastern Himalaya. To clarify how short-lived glacial lakes store and drain water over short periods, we use results from a field survey and satellite data to analyze the water level, area, volume, and discharge of Korumdu lake (2017–2019) as well as satellite data to monitor the appearance of 160 other short-lived lakes (2013–2018). Except in 2016, Korumdu lake appeared and drained within about 1 month during all the summers. Water level data recorded by a data logger and time-lapse camera images show that the lake appeared and expanded suddenly from July to August in 2017–2019. The timing of lake appearance indicates that the lake formed when an outlet ice tunnel (subsurface channel) drainage was blocked by depositions of an ice–debris mixture due to ice melting and not by freezing of stored water. For 2017, we used uncrewed aerial vehicle (UAV)-derived digital surface models (DSMs) and water levels, finding that the lake's volume reached 234 000 m3 within 29 d, and then the water discharged for 17 d at a maximum rate of 0.66 m3/s. This discharge rate is more than 20 times smaller than those found earlier (2006–2014) for four short-lived lakes of tunnel type in this region. We argue that this large variation in discharge rates is due to variation in the dimensions of the outlet ice tunnels. For the 160 other short-lived glacial lakes, we found that 117 formed during the ice-melt period from July to September. This timing and our findings for Korumdu lake show that these 117 lakes likely formed primarily because deposition of an ice–debris mixture blocked the outlet tunnel, though increased glacial melt would also have contributed. In the Teskey Range, the appearance of short-lived glacial lakes on the moraine complexes at glacier fronts is inevitable in summer when the melting rate is high. Similar behavior of short-lived lakes may occur in other mountain regions of Central Asia, such as the Tien Shan and Pamir Mountains, wherever ice-cored moraine complexes exist within mountain permafrost zone. Moreover, increasing temperatures may increase both tunnel size and lake-basin size (lake volume), leading to increased hazard potential from such lakes in the future.

Quality and Evaluation Report: Virtual Fracture Clinic at Wythenshawe Hospital

Background: Following its introduction at Glasgow Royal Infirmary in 2011, the Virtual Fracture Clinic model of managing outpatient musculoskeletal injuries has grown significantly in popularity. Wythenshawe Hospital introduced this model to their orthopaedic department in 2015. Aims: How do individual consultants vary in terms of discharge rate versus face-to-face follow up when reviewing cases in a Virtual Fracture Clinic? To assess patients’ level of satisfaction with the management of their injury under a Virtual Fracture Clinic System. Methods: A retrospective study of a cohort of patients over 12 months from 11th May 2017 to 11th May 2018. Data regarding the number of patients reviewed in Virtual Fracture Clinic during this time was collected and the numbers of patients discharged or recalled for follow up analysed. A telephone questionnaire based on the NHS Friends and Family Test was collected from 50 patients within this cohort to assess overall satisfaction with their care. Results: 3361 patients were referred to virtual fracture clinic during the inclusion period. The mean percentage of cases discharged from virtual fracture clinic is 30.4% with a median of 30.5%. The rates of discharge ranged from Consultant G at 13% to Consultant K at 39%. 88% of patients would recommend this service to their friends and family and 80% would rate the service at the level of good or excellent. Conclusion: A virtual fracture clinic model has been successfully implemented at Wythenshawe saving approximately 1157 appointments in 12 months. There is significant variation in discharge rates between consultants which appears to be influenced by the number of patients seen. Individual factors which affect this require further investigation. Patients are very satisfied with their care through the Virtual Fracture Clinic at Wythenshawe Hospital and an overwhelming majority would recommend this to others.

Review: Approaches to groundwater exploration and resource evaluation in the crystalline basement aquifers of Zimbabwe

Assessment of the groundwater potential of crystalline basement aquifers is challenging. These systems can be highly spatially variable, as indicated by the drilling of numerous dry boreholes and seasonal variation in discharge rates. This paper reviews methodologies applied for the evaluation of groundwater occurrence and yield estimation in the crystalline basement aquifers of Zimbabwe. These aquifers underlie much of the country and are described in terms of low yield owing to low recharge potential in the semiarid climate. In such regions, exploitable groundwater forms a strategic supply of potable water used to meet the socio-economic needs of the local population. Case studies are used to show how remote sensing and geophysical methods are integrated to improve borehole success rates in the basement aquifers of Zimbabwe. Potential threats to groundwater resources and quality within crystalline basement aquifers are discussed. It can be concluded that major issues remain to be addressed if sustainable use of the water resources of crystalline basement aquifers in Zimbabwe is to be achieved, especially with respect to borehole-siting approaches and prevention of groundwater contamination. The key recommendation is to address the paucity of primary groundwater monitoring data within the crystalline basement aquifers at the national level, thereby creating a technical groundwater management framework.

A Quality Improvement Project to Reduce Substance Misuse-Associated Discharges in an Outpatient Palliative Care Clinic: Establishment of the Interdisciplinary High Alert Risk Team (HART) (TH308C)

•Specify the challenges of outpatient clinic care for patients who engage in or are at risk for substance misuse.•Define an interdisciplinary approach to optimize support and retention of clinic patients and providers when controlled substances are prescribed and misused. Illicit substance abuse and controlled medication misuse are common in medical practice, jeopardize patient safety and may negatively impact providers. Inflexible low-tolerance policies regarding substance misuse may adversely affect anticancer care, particularly for patients with a high symptom burden. From 2014-2016, 19.9% of Moffitt Cancer Center Palliative Care (PC) clinic patients were noncompliant with controlled medication policy and 47 (4.6%) were discharged from 2015-2016. Clinic personnel were dissatisfied with clinic processes for support of patients and providers in the setting of substance misuse. Reduce substance misuse-related clinic discharges and associated clinician dissatisfaction. In 2016 an interdisciplinary workgroup was convened to identify challenges, barriers and inconsistencies in provider, patient and process characteristics of substance misuse-related clinic discharges. Gap analysis pinpointed opportunities for improvement. The High Alert Risk Team (HART) was established to support patients at risk for aberrant behaviors and their clinicians. Roles include patient education by nursing, safety-oriented prescribing arrangements with physicians, patient relations representation to advocate and set expectations and social worker counseling and support. HART policy, user-friendly controlled substance agreements, patient screening, compliance monitoring, patient and provider support, and documentation were developed and implemented. Discharges compared to patient volumes were tracked and provider satisfaction with the quality improvement project was surveyed. A total of 1,621 outpatients have been seen in the PC clinic from 2015-2017. Substance-related PC clinic discharges have decreased overall from 25 (6.53%) in 2015 to 9 (1.48%) through July, 2017. Discharge rates still vary among clinicians. All clinic survey respondents (n=9) affirmed that care of patients with high risk behaviors and support of personnel have improved since HART implementation. A team-based quality improvement approach successfully reduced outpatient PC clinic substance misuse-related discharges and increased team satisfaction. Provider and patient characteristics likely account for variation in discharge rates among specialists and will be further explored.

Unexplained Variation for Hospitals' Use of Inpatient Rehabilitation and Skilled Nursing Facilities After an Acute Ischemic Stroke.

Rehabilitation is recommended after a stroke to enhance recovery and improve outcomes, but hospital's use of inpatient rehabilitation facilities (IRFs) or skilled nursing facility (SNF) and the factors associated with referral are unknown. We analyzed clinical registry and claims data for 31 775 Medicare beneficiaries presenting with acute ischemic stroke from 918 Get With The Guidelines-Stroke hospitals who were discharged to either IRF or SNF between 2006 and 2008. Using a multilevel logistic regression model, we evaluated patient and hospital characteristics, as well as geographic availability, in relation to discharge to either IRF or SNF. After accounting for observed factors, the median odds ratio was reported to quantify hospital-level variation in the use of IRF versus SNF. Of 31 775 patients, 17 662 (55.6%) were discharged to IRF and 14 113 (44.4%) were discharged to SNF. Compared with SNF patients, IRF patients were younger, more were men, had less health-service use 6 months prestroke, and had fewer comorbid conditions and in-hospital complications. Use of IRF or SNF varied significantly across hospitals (median IRF use, 55.8%; interquartile range, 34.8%-75.0%; unadjusted median odds ratio, 2.59; 95% confidence interval, 2.44-2.77). Hospital-level variation in discharge rates to IRF or SNF persisted after adjustment for patient, clinical, and geographic variables (adjusted median odds ratio, 2.87; 95% confidence interval, 2.68-3.11). There is marked unexplained variation among hospitals in their use of IRF versus SNF poststroke even after accounting for clinical characteristics and geographic availability. URL: https://clinicaltrials.gov. Unique identifier: NCT02284165.

English

The use of wastewater in irrigated agriculture is an alternative to the lack of water resources of higher quality and allows obtaining, besides the reuse, environmental improvements. In the application of wastewaters, such as treated domestic sewage, localized drip systems are affected by the decrease in application of uniformity and discharge rate of the emitters, due to clogging. In this context, this study aimed to characterize the material of the biofouling and evaluate its effects on the hydraulic performance of emitters utilized in drip irrigation with wastewater from treated domestic sewage. The experiment was carried out on a bench at the field, in the Brazilian semi-arid region, in the state of Paraiba, Brazil, and consisted of the application of wastewater and public-supply water using three models of labyrinth-type emitters. The hydraulic performance of the emitters was monitored through the variation in discharge rate and coefficient of uniformity along 1188 h of operation. X-ray spectroscopy analysis was performed to characterize the chemical composition of the material that caused biofouling. The chemical elements identified in the characterization of the biofouling material were sodium, magnesium, aluminum, silicon, chlorine, calcium, iron, carbon and oxygen; the latter two were found in higher amounts. In addition, the presence of fluorine was also detected. Biofouling caused linear and quadratic reduction in the discharge rate of the emitters over the time of operation. Both wastewater and the hydraulic characteristics of the labyrinth contributed to clogging of the emitters. Key words: Biofilm, X-ray spectroscopy, uniformity coefficient, wastewater, emitter clogging.

Volume Matters: Returning Home After Hip Fracture.

To examine the effect of the relationship between volume (number of hip fracture admissions during the 12 months before participant's fracture) and other facility characteristics on outcomes. Prospective observational study. U.S. skilled nursing facilities (SNFs) admitting individuals discharged from the hospital after treatment for hip fracture between 2000 and 2007 (N = 15,439). Community-dwelling fee-for-service Medi-care beneficiaries aged 75 and older admitted to U.S. hospitals for their first hip fracture and discharged to a SNF for postacute care from 2000 to 2007 (N = 512,967). Successful discharge from SNF to community, defined as returning to the community within 30 days of hospital discharge to the SNF and remaining in the community without being institutionalized for at least 30 days, was examined using Medicare administrative data, propensity score matching, and instrumental variables. The overall rate of successful discharge to the community was 31%. Of the 15,439 facilities, the facility interquartile range varied from 0% (25th percentile) to 42% (75th percentile). An important determinant of variation in discharge rate was SNF volume of hip fracture admissions. Unadjusted successful discharge from SNF to community was 43.7% in high-volume facilities (>24 admissions/year), versus 18.8% in low-volume facilities (1-6 admissions/year). This facility volume effect persisted after adjusting for participant and facility characteristics associated with outcomes (e.g., adjusted odds ratio = 2.06, 95% confidence interval = 1.91-2.21 for volume of 25 vs 3 admissions per year). In community-dwelling persons with their first hip fracture, successful return to the community varies substantially according to SNF provider volume and staffing characteristics.

독도 서도 물골 지하수의 유출특성

The discharge characteristics of the Seodo Mulgol Spring-the only groundwater-producing area in Dokdo-were evaluated by measurements of discharge rate and electrical conductivity (EC) on five occasions. The Seodo Mulgol Spring is fed by rainfall in upstream areas of the Mulgol cave, and the rainwater of the area moves down along cooling joints developed in trachyandesite II and trachyte, finally discharging at the Mulgol cave. The discharge rate of the Seodo Mulgol Spring varied from 1.12 to 7.02 during the study period and EC varied from 2,650 to 3,390 , showing a sharp increase during heavy rainfall. The observed variations in discharge rate and EC at the Seodo Mulgol Spring are attributed to the relatively short distance between the recharge area and the Mulgol cave, and to the rapid movement of groundwater through columnar joints developed in trachyandesite II and trachyte. Additional discharge measurements, combined with precise rainfall data, are required at Dokdo to elucidate the discharge characteristics of the Seodo Mulgol Spring.

Eruptive history and magmatic evolution of the 1.9 kyr Plinian dacitic Chiltepe Tephra from Apoyeque volcano in west-central Nicaragua

The youngest dacitic Plinian eruption in west-central Nicaragua, forming the 18 km3 Chiltepe Tephra (CT), occurred about nineteen hundred years ago at Apoyeque stratovolcano, which dominates the Chiltepe volcanic complex 15 km north of the capital Managua, where the CT is 2 m thick. We have traced the CT from its proximal facies at the crater rim, through the medial facies in the lowlands around Apoyeque, and to the distal facies up to 550 km offshore in the Pacific. While medial and distal facies consist of widespread Plinian fall deposits, the proximal facies reveals the complexity of this eruption, which we divide into four phases (I–IV). Interaction of rising magma with a pre-existing crater lake generated the phreatomagmatic opening phase I of the eruption, which produced ash fall with accretionary lapilli. Phase II marked a rapid change to persistent magmatic activity that yielded several large Plinian eruptions, declining through a period of unstable eruption conditions, followed by a short hiatus. Phase III began with unstable conditions, probably as a result of eastward migration and widening of the vent, leading to a second period of Plinian eruptions with three major events reaching magma discharge rates five times larger than those of phase II. Phase III again declined through unstable eruption conditions before magmatic activity terminated. Numerous explosions in the shallow hydrothermal system during the final phase IV resulted in the formation of a phreatic tuff ring on the rim of Apoyeque crater. The white, highly-vesicular, dacitic CT pumice contains plagioclase (An45–68), orthopyroxene, clinopyroxene, and minor hornblende, apatite and titanomagnetite phenocrysts. A very subordinate fraction of gray pumice has the highest crystal content, the least evolved bulk-rock, but the most evolved matrix-glass composition. The CT dacite has two unusual compositional features: (1) all white dacite has the same melt (matrix-glass) composition such that variations in bulk-rock compositions (64–68 wt% SiO2) simply reflect different phenocryst contents of 10–35%, interpreted as the result of gradual phenocryst settling in the magma chamber. (2) Abundant olivine crystals with a bimodal distribution in Mg# (modes at Mg# = 0.75 and Mg# = 0.8) are dispersed throughout the erupted dacite. These are clearly out of equilibrium with the dacitic melt and are interpreted as xenocrysts derived from the basaltic Nejapa-Miraflores volcanic lineament that intersects the Chiltepe volcanic complex and was contemporaneously active. Thermobarometric estimates place the dacitic CT magma reservoir in the upper crust (<250 MPa), with a temperature of about 890°C and about 5 wt% water dissolved in the melt. Comparing water and chlorine contents with respective solubility models suggests that volatile degassing began in the magma reservoir and triggered the CT eruption. From the vertical compositional variation pattern of the CT we deduce that the conduit tapped the magma chamber not at the top but from the side, at some deeper level, and that subsequent magma withdrawal was governed by both variations in discharge rate and possible upward migration and/or widening of the conduit entrance.

How much do operational processes affect hospital inpatient discharge rates?

The objective of this study is to determine the effect of day of the week, holiday, team admission and rotation schedules, individual attending physicians and their length of coverage on daily team discharge rates. We conducted a retrospective analysis of the General Internal Medicine (GIM) inpatient service at our institution for years 2005 and 2006, which included 5088 patients under GIM care. Weekend discharge rate was more than 50% lower compared with reference rates whereas Friday rates were 24% higher. Holiday Monday discharge rates were 65% lower than regular Mondays, with an increase in pre-holiday discharge rates. Teams that were on-call or that were on call the next day had 15% higher discharge rates compared with reference whereas teams that were post-call had 20% lower rates. Individual attending physicians and length of attending coverage contributed small variations in discharge rates. Resident scheduling was not a significant predictor of discharge rates. Day of the week and holidays followed by team organization and scheduling are significant predictors of daily variation in discharge rates. Introducing greater holiday and weekend capacity as well as reorganizing internal processes such as admitting and attending schedules may potentially optimize discharge rates.

Counterpoint: Spectral properties of the surface emg do not provide information about motor unit recruitment and muscle fiber type

The surface electromyogram (EMG) comprises the sum of the electrical contributions made by the active motor units to the interference signal detected by electrodes placed on the skin overlying the muscle. Because it provides a global measure of motor unit activity, this signal is a valuable tool for

Classification of springs of Jeju Island using cluster analysis of annual fluctuations in discharge variables: investigation of the regional groundwater system

The springs of Jeju Island have been studied since 1999. However, previous studies did not provide a systematic analysis of survey results. Thus, we performed a systematic analysis of the groundwater flow system using cluster analysis of discharge variables, i.e., discharge rate, electrical conductivity (EC), and temperature, at 121 springs. The 121 springs were categorized into nine major groups based on discharge rates and ten groups based on EC. Springs in groups 1, 2, and 3 in discharge cases had peak discharge rates in September, October, and occasionally in November, following the rainy season. Other springs showed complex seasonal variation in discharge rates. Springs in groups 4–1, 4–3, 5–2, 9–1, and 9–2 had peak discharge rates in winter (December–February). The results of classification by EC were directly correlated with the absolute values of and seasonal variation in EC. Based on EC, springs in group 1 had relatively low EC of > 500 μS/cm in general. The highest EC at each spring in group 1 was 110–18,000 μS/cm. Coastal springs generally had higher EC than did springs located inland. The relation between discharge rate and EC was of interest. At some springs, discharge rate and EC were proportional, especially in winter. The proportionality between discharge and EC cannot be explained by the conventional groundwater management model of Jeju Island. To explain this proportionality, we examined the results of previous studies with regard to geological features, well locations, hydraulic head and hydraulic gradient distributions, and vertical reduction in groundwater EC within the zone influenced by saline water. We then proposed a hypothetical regional conceptual model of groundwater flow for Jeju Island. More precise studies are needed to clarify the relationships among responses at surveyed springs, hydraulic features in coastal areas, and the regional conceptual model for groundwater circulation on Jeju Island.

Controls of conduit geometry and wallrock elasticity on lava dome eruptions

Many lava dome building eruptions show periodic to complex non-periodic pulsatory activity. Typical time-scales associated with this activity range from hours to decades. Previous studies modelled the ascent of magma using a set of transient 1-D transport equations, accounting for degassing induced crystallization kinetics, gas exsolution and viscosity increase due to crystal growth. These models assumed flow in a cylindrical conduit with a fixed cross-section area. Since several observations suggest that extrusions are mainly fed by dykes, with cylindrical geometries developing only at shallow levels, here we generalised the model to the flow geometry represented by an elliptical dyke with major and minor semi-axes changing with depth. Quasi-static elastic deformation of the dyke is accounted by an analytical solution that couples cross-section area with the magmatic overpressure. The effects of the main dyke geometrical parameters and boundary conditions on the eruption dynamics were investigated. The presence of a deformable dyke can lead to a more complex periodic behaviour with a wider range of time-scales and cyclicity patterns with respect to a uniform cylindrical conduit. There is a regime where the period of pulsations is controlled by the elasticity of the dyke and a regime where the period is controlled by the volume of the magma chamber. Intermediate regimes are possible. Periodic variations in discharge rate are also possible for both fixed pressure in dyke source region and fixed influx rate into the dyke. Our study emphasizes the strong non-linearities and complex behaviours of lava dome eruptions. From a forecasting and hazard perspective, intrinsic uncertainties in governing parameters may make volcanic systems in some circumstances unpredictable. On the other hand, lava dome systems may also develop episodic and systematic behaviours so that behaviour becomes predictable for a while.

Controls on conduit magma flow dynamics during lava dome building eruptions

Lava dome eruptions commonly display fairly regular alternations between periods of high and low or no activity with timescales typically of weeks to years and sudden transitions between effusive and explosive activity. We develop a transient model of the magma flow in a volcanic conduit from an open‐system magma chamber with continuous replenishment. The model incorporates gas exsolution, bubble growth, gas escape through the magma, and decompression‐induced crystallization and considers variations in magma temperature, water content, conduit diameter, phenocryst size, chamber volume, and magma rheology. Calculations show the presence of periodic variations in discharge rate due to the transition from a stable regime, when discharge rate is low and crystals grow efficiently leading to high magma viscosity, to another stable state, when discharge rate is high and crystallization is negligible. The difference in discharge rates between these regimes can be several orders of magnitude. Periods are similar to the observed timescales and mainly depend on the chamber volume. The system shows strongly nonlinear responses to the variation of governing parameters. If magma has a Bingham rheology pauses in discharge rate occur between peaks of discharge and the peaks are much higher than for the case of Newtonian rheology. Large changes in discharge rate and eruptive behavior can occur as the consequence of small changes in magma temperature, water content, phenocryst size distribution, or conduit diameter. The system can fluctuate between low and high discharge rates with transitions to explosive activity.

Dynamics of magma ascent and lava extrusion at Soufrière Hills Volcano, Montserrat

Abstract Growth of the andesitic lava dome during eruption of Soufrière Hills Volcano, Montserrat involved general increases in discharge rate and dome height with superposed fluctuations on timescales from hours to months. We have modelled magma conduit flow incorporating viscosity variations caused by degassing and crystallization. Gas loss is modelled by permeable flow, with variations of permeability constrained by measurements. Crystallization kinetics is modelled by an Avrami law. Observations and petrological studies constrain conduit diameter ( c . 30 m), magma chamber crystal content ( c . 60-65%), melt water content ( c . 5%), magma temperature ( c . 850°C) and chamber depth ( c . 5 km). Gas loss and rheological stiffening cause a maximum in magma overpressure (magma pressure minus lithostatic pressure) at depths of a few hundred metres below the dome. This maximum can explain ground deformation patterns, shallow seismicity, and short-lived Vulcanian explosions. Crystallization kinetics causes a strong feedback mechanism and multiple steady solutions for discharge rate. Small changes in chamber pressure, magma viscosity and conduit diameter strongly amplify discharge rate. Multiple solutions allow cyclic variation of discharge rate. Escalation of activity is attributed principally to influx of hot mafic magma into the chamber, resulting in chamber pressure increasing with time. Dome growth can be intrinsically unpredictable due to non-linear effects.

Spike-frequency adaptation: Phenomenological model and experimental tests

Spike-frequency adaptation is a common feature of neural dynamics. Here we present a low-dimensional phenomenological model whose parameters can be easily determined from experimental data. We test the model on intracellular recordings from auditory receptor neurons of locusts and demonstrate that the temporal variation of discharge rate is predicted with high accuracy. We relate the model to biophysical descriptions of adaptation in conductance-based models and analyze its implications for neural computation.

Neuronal Synchrony: A Versatile Code for the Definition of Relations?

Neuronal Synchrony: A Versatile Code for the Definition of Relations?

Field Observations of Tidal and Seasonal Variations in Ground Water Discharge to Tidal Estuarine Surface Water

AbstractA field study of the tidal and seasonal variations in upland, shoreline, and nearshore hydrological processes associated with ground water discharge from the unconfined Columbia Aquifer was conducted. The study, performed along a tidal subestuary of the Chesapeake Bay, involved measurement of water table elevation, ground water discharge, potentiometric had differentials across the sediment‐water interface, and ground water salinity. Fresh ground water discharge rates calculated from the measured water table gradient using the Dupuit assumptions varied from 6.1 X 10‐3 to 3.8 X 10‐2 m3/day per m of shoreline during the study period, May 1994 to September 1995. Variation in discharge rates were associated with seasonal recharge patterns.Integrated total discharge rates based on seepage meter measurements decreased with distance offshore from a maximum of 3.3 L/m2 hr at the shoreline to 0.5 L/m2hr at 30 m offshore Maximum instantaneous discharge rates calculated from potentiometric head differentials were much higher than integrated discharge rates and ranged from 19.2 L/m2hr at 4.8 m offshore to 0.8 L/m2hr at 19.8 m offshore. Instantaneous discharge rates were inversely correlated to tidal elevation and fluctuated rapidly decreasing from 19.2 L/m2hr to 2.5 L/m2 hr during a several‐hour period.Seasonal variations in salinity patterns within the transition zone of the Columbia Aquifer were observed and indicated a dependence on fresh ground water discharge and surface water salinity/density gradient was observed within the transition zone. The gradient was created, in part, by the infiltration of surface water into tidally exposed sediments. Seasonal periods of low fresh ground water discharge and high surface water salinity were associate with intrusion of the surficial mixing zone landward while seasonal periods of high fresh ground water discharge and low surface water salinity were associated with a seaward movement of the mixing zone.

Rheumatology out-patient workload increases inexorably.

Rheumatology out-patient consultations in the south-west of England from 1 to 30 November 1994 were recorded by standard methods and compared to 1988, 1990, 1991 and 1992. Historical records at one centre provided additional detailed information. There has been an overall increase of 31% in the number of patients seen (30% for follow-up cases, 36% for new referrals), but the mean waiting time for new patient consultations increased from 65 to 108 days. The proportion of new patient consultations with non-arthritic diseases increased by 8.2%, and those with rheumatoid arthritis and polyarthritis decreased by 9.0%. Variation in discharge rates and length of follow-up appointments occurred, but mostly in uncommon diagnostic categories. Referral rates have been rising faster since the introduction of National Health Service reforms than can be accommodated by the increased workload undertaken.