A simplified mathematical model for predicting the nocturnal output of a solar still

The production capacity of a solar still which converts saline water to fresh water can be increased by introducing hot feed water into the unit at night. A waste heat source, such as cooling water from a power plant, can be used to preheat the feed. The nocturnal production, i.e. the distilled water produced at night, seems to be influenced by several parameters. However, a simplified mathematical model suggests that the distillate depends only on the initial brine temperature, the drop in brine temperature and the brine depth. This was experimentally verified for different brine depths and for initial brine temperatures up to 150°F.     

Longitudinal working models: Estimates of household energy consumption in Australia

The paper uses household expenditure survey data and alternative functional specifications of Engel's laws to establish an empirical pattern of disaggregate energy (ie electricity, gas, other fuels and gasoline) demand characterized by different demographic attributes for use in a combined panel data model of energy consumption and impact in Australia. The findings lend support, in terms of statistical efficiency and economic–theoretic plausibility, to the dominance of the Working form over the conventional linear Allen–Bowley function. Energy as a whole is a necessity while at the disaggregate level gasoline is considered a luxury. The findings indicate in this respect the existence of demand elasticity bias in aggregate energy models.     

Changes in the proton potential and the cellular energetics of Escherichia coli during growth by aerobic and anaerobic respiration or by fermentation

The energetic parameters of Escherichia coli were analyzed for the aerobic/anaerobic transition. The electrochemical proton potential (delta p) across the cytoplasmic membrane was determined in the steady state of respiration with O2, nitrate, fumarate, dimethylsulfoxide (Me2SO), and for fermentation. With O2, a proton potential of -160 mV was obtained. For anaerobic respiration with nitrate, fumarate or Me2SO, delta p decreased only slightly by about 20 mV in contrast to earlier assumptions, whereas delta p dropped by approximately 40 mV during fermentation. Under all conditions, the membrane potential (delta psi) contributed the major portion to delta p. The cellular ATP levels were highest for aerobic growth (about 13 micromol/g dry cells) and decreased to 3-6 micromol/g in anaerobic metabolism. Delta G'Phos, however, was constant due to equivalent changes of the ADP contents. Transition to the stationary growth phase caused a massive drop in the ATP content. It is concluded that, during anaerobic respiration, the energetic situation for the bacteria is very similar to that for aerobic growth with respect to delta G'Phos and delta p whereas, for fermentation, a significant decrease in delta p was observed. The consequences for the cellular energetics and for the regulation of the aerobic/anaerobic transition are discussed.     

Central cardiovascular effects of tacrine in the conscious dog: a role for catecholamines and vasopressin release

Centrally acting cholinergic agents are currently reported to increase blood pressure in various species through the stimulation of muscarinic cholinoceptors. Moreover, several cardiovascular adverse effects have been reported from clinical studies. The aim of this study was to investigate the effects of tacrine, an acetylcholinesterase inhibitor which has been reported to have therapeutic potential in Alzheimer's disease, on blood pressure and two vasopressor systems (sympathetic and vasopressinergic) in Beagle dogs. Intravenous (i.v.) tacrine (2 mg kg(-1)) induced, in conscious and anesthetized dogs, an increase in systolic and diastolic blood pressure, accompanied by bradycardia. This increase was dose-dependent with a peak effect at 1.5 min following administration. Tacrine also induced an increase in noradrenaline, adrenaline and vasopressin plasma levels. Pretreatment with the muscarinic receptor antagonist, atropine (2 mg kg(-1), i.v.), abolished the pressor response to i.v. injection of tacrine while pretreatment with the peripheral muscarinic receptor antagonist, methylscopolamine (0.2 mg kg(-1), i.v.), did not alter the increase in blood pressure. Similarly, noradrenaline and adrenaline changes in plasma levels were not modified by methylscopolamine but were abolished by atropine pretreatment. A similar tendency although not significant was observed for vasopressin plasma levels. The present results demonstrate that in dogs, tacrine (2 mg kg(-1), i.v.) stimulates central muscarinic cholinoceptors to increase blood pressure through activation of the two components of the sympathetic nervous system (i.e., neuroneuronal noradrenergic and the neurohormonal adrenergic pathways) as well as through increasing noradrenaline, adrenaline and vasopressin plasma levels.     

Grapefruit juice-terfenadine single-dose interaction: magnitude, mechanism, and relevance

Effective management of human health and ecological hazards in the manufacturing and maintenance environment can be achieved by focusing on the risks associated with these operations. The NDCEE Industrial Health Risk Assessment (IHRA) Program is developing a comprehensive approach to risk analysis applied to existing processes and used to evaluate alternatives. The IHRA Risk-Based Tiered Approach (RBTASM) builds on the American Society for Testing and Materials (ASTM) Risk-Based Corrective Action (RBCA) effort to remediate underground storage tanks. Using readily available information, a semi-quantitative ranking of alternatives based on environmental, safety, and occupational health criteria was produced. A Rapid Screening Assessment of alternative corrosion protection products was performed on behalf of the Joint Group on Acquisition Pollution Prevention (JG-APP). Using the RBTASM in pollution prevention alternative selection required higher tiered analysis and more detailed assessment of human health risks under site-specific conditions. This example illustrates the RBTASM for a organic finishing line using three different products (one conventional spray and two alternative powder coats). The human health risk information developed using the RBTASM is considered along with product performance, regulatory, and cost information by risk managers downselecting alternatives for implementation or further analysis.     

Podiatric medical resources on the Internet

PURPOSE: To determine utility of polymerase chain reaction (PCR)-based urine screening for Chlamydia trachomatis in the care of adolescent females in an urban clinic. METHODS: Females > or = 15 years of age attending an adolescent clinic were approached consecutively. Each enrollee was interviewed to determine the primary reason(s) for the clinic visit and was queried about genitourinary symptoms. Nonsterile voided urine specimens were tested for C. trachomatis using PCR-based analysis. Endocervical C. trachomatis cultures were obtained from the subjects who had a pelvic examination. Main outcome measures were chlamydia infection rates in clinic attendees whether a pelvic examination was performed or not. RESULTS: A total of 315 (99.4%) of 317 patients approached agreed to participate. Overall, 47 (14.9%) patients had positive urine PCR tests. The chlamydia infection rate detected by urine PCR was 22.1% (19 of 86) among those who had pelvic examinations performed and 12.2% (28 of 229) among those who did not (p = .03; odds ratio 2.04; 95% confidence interval 1.02, 4.06). Sixty percent (28 of 47) of chlamydia infections identified during the study period were identified by the urine screening test. CONCLUSION: Urine screening was accepted by vast majority of female adolescents attending the clinic irrespective of reason for the clinic visit, and was highly effective in identifying unsuspected C. trachomatis infections, particularly among girls attending the clinic for reasons unrelated to reproductive health care and as an interim screening tool for adolescent family-planning clients.     

Attachment and the experience and expression of emotions in romantic relationships: A developmental perspective.

In this longitudinal study, the authors tested a developmental hypothesis derived from attachment theory and recent empirical findings. Target participants were 78 individuals who have been studied intensively from infancy into their mid-20s. When targets were 20-23 years old, the authors tested the way in which interpersonal experiences at 3 pivotal points in each target's earlier social development--infancy/early childhood, early elementary school, and adolescence--predicted the pattern of positive versus negative emotions experienced with his or her romantic partner. A double-mediation model revealed that targets classified as securely attached at 12 months old were rated as more socially competent during early elementary school by their teachers. Targets' social competence, in turn, forecasted their having more secure relationships with close friends at age 16, which in turn predicted more positive daily emotional experiences in their adult romantic relationships (both self- and partner-reported) and less negative affect in conflict resolution and collaborative tasks with their romantic partners (rated by observers). These results are discussed in terms of attachment theory and how antecedent life experiences may indirectly shape events in current relationships. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Installation of Suction Caissons in Sand with Silt Layers

Suction caissons are increasingly being used for offshore anchors because of their ease of installation. However, for soil profiles that have sand overlain by layers of silt, there are reasons to believe that it may not be possible to install suction caissons. This may happen because the low permeability of the silt will create a hydraulic blockage, and thus diminish the upward hydraulic gradient required to reduce the penetration resistance in the sand to enable caisson penetration. The tendency of the silt to be sucked up, and its effect on the underlying sand, are not clearly understood. Furthermore, the blockage by the silt layer may be less than if a clay layer is present. This is because scouring of the silt may occur, allowing an upward seepage gradient to develop, and hence causing a reduction in penetration resistance. A series of suction caisson installation tests have been conducted in a geotechnical centrifuge to provide data on the penetration resistance and mechanisms for soil profiles where silt layers are present, either on top, or interbedded between layers of sand. In these tests, the thickness of the silt layer and its depth below the sand surface have also been varied. It has been found that if silt overlies the sand, a larger suction force is required for installation than when installation occurs in homogeneous sand, but that this force is still much smaller than the soil resistance when the caisson is pushed into the ground. When a silt layer is present, the suction pressures are observed to follow a similar trend that is independent of the position and thickness of the silt layer. Scouring of silt was evident in the tests, and significant upward movement of the soil plug inside the caisson was observed in all soil profiles when silt layers were present. The plug height was seen to reduce after the suction was turned off, suggesting that the resulting heave was unstable.     

Response to dopamine vs norepinephrine in tricyclic antidepressant-induced hypotension

OBJECTIVE: To compare the efficacy of dopamine (DA) with that of norepinephrine (NE) in the treatment of refractory hypotension caused by tricyclic antidepressants (TCAs). METHODS: A retrospective analysis was used to compare blood pressure responses in concurrent case series of patients treated with vasopressors for TCA-associated hypotension. The patients were adults (aged > or = 16 years) treated at 2 urban teaching hospitals from 1983 to 1994. All patients were diagnosed as having TCA ingestion (positive serum toxicologic assay), were hypotensive [systolic blood pressures (SBPs) < or = 90 mm Hg], and required vasopressor therapy. The patients were grouped by initial vasopressor treatment (i.e., NE vs DA). RESULTS: There were 26 hypotensive adult patients who met study criteria. All 26 patients remained hypotensive after initial treatment of their TCA-associated hypotension with crystalloid infusion and alkalinization. The NE and DA groups were similar in age, sex, and proportion of patients with single and co-drug ingestion. The NE group, however, had a significantly lower average SBP at study entry (56 vs 74 mm Hg, p = 0.04). Nine of 15 (60%) patients responded to DA (5-10 micrograms/kg/min) and 11/11 (100%) patients responded to NE (5-53 micrograms/min). The difference in response rates was statistically significant (p = 0.02). Six patients in whom DA (max rate 10-50 micrograms/min/kg) failed to raise the SBP subsequently responded to NE (max rate 5-74 micrograms/ min) when this drug was later used. One patient receiving NE (12 micrograms/min) developed ventricular ectopy, successfully treated with lidocaine. There were no ischemic complications from either NE or DA. Patients who failed DA therapy tended to be older (39 vs 30 years, p = 0.08), to be more hypotensive at study entry (64 vs 81 mm Hg, p = 0.008), and to remain hypotensive even at higher doses of DA (24 vs 7 micrograms/min/kg, p = 0.002). CONCLUSION: While this was not a prospective randomized study, NE appears advantageous over DA as the first-line vasopressor agent for those patients who require vasopressor support in the setting of TCA-induced hypotension that is refractory to IV fluid and serum alkalinization.     

Successful surgical treatment of intraorbital arteriovenous malformations: case report

OBJECTIVE: Our purpose was to establish whether obstetric ultrasonography interpreted by a live video telemedicine link is comparable to interpretation by videotape review in a low-risk patient population. STUDY DESIGN: An Integrated Services Digital Network (ISDN 6) was established from three satellite offices to our central prenatal diagnostic center. Patients seen at these satellite offices had a complete fetal anatomic survey recorded onto videotape by a trained ultrasonographer. A live interactive video telemedicine link was then established to our center by the digital network, and a perinatologist directed the ultrasonographer through the anatomy survey. Subsequently a different perinatologist, blinded to the telemedicine interpretation, reviewed the videotaped examination. The reports from the videotaped and telemedicine scans were then compared on the basis of a score of 33 anatomic items. RESULTS: The first 200 patients seen at the satellite offices were included. Telemedicine and videotape interpretations provided similar scores in 84% of scans. In 17 of the 33 anatomic categories telemedicine provided significantly better scores than videotape, whereas in the remaining 16 anatomic categories the scores were equivalent. More videotape than telemedicine examinations required repeat ultrasonography because of suboptimal imaging (10% vs 3%, p = 0.003). CONCLUSIONS: The interpretation of obstetric ultrasonography with use of live video telemedicine is comparable to videotape review. Fetal telemedicine may prove to be a useful tool for providing ultrasonographic interpretation of fetal anatomy to a network of low-risk obstetric practices.