bluuebunny/crossref_metadata_2025 huggingface dataset:
A hydrogeologic model of stratiform copper mineralization in the Midcontinent Rift System, Northern Michigan, USA
Authors: Swenson J. B. , Person M. , Raffensperger J. P. , Cannon W. F. , Woodruff L. G. , Berndt M. E.
Published: January 2004

This paper presents a suite of two‐dimensional mathematical models of basin‐scale groundwater flow and heat transfer for the middle Proterozoic Midcontinent Rift System. The models were used to assess the hydrodynamic driving mechanisms responsible for main‐stage stratiform copper mineralization of the basal Nonesuch Formation during the post‐volcanic/pre‐compressional phase of basin evolution. Results suggest that compaction of the basal aquifer (Copper Harbor Formation), in response to mechanical loading during deposition of the overlying Freda Sandstone, generated a pulse of marginward‐directed, compaction‐driven discharge of cupriferous brines from within the basal aquifer. The timing of this pulse is consistent with the radiometric dates for the timing of mineralization. Thinning of the basal aquifer near White Pine, Michigan, enhanced stratiform copper mineralization. Focused upward leakage of copper‐laden brines into the lowermost facies of the pyrite‐rich Nonesuch Formation resulted in copper sulfide mineralization in response to a change in oxidation state. Economic‐grade mineralization within the White Pine ore district is a consequence of intense focusing of compaction‐driven discharge, and corresponding amplification of leakage into the basal Nonesuch Formation, where the basal aquifer thins dramatically atop the Porcupine Mountains volcanic structure. Equilibrium geochemical modeling and mass‐balance calculations support this conclusion. We also assessed whether topography and density‐driven flow systems could have caused ore genesis at White Pine. Topography‐driven flow associated with the Ottawan orogeny was discounted because it post‐dates main‐stage ore genesis and because recent seismic interpretations of basin inversion indicates that basin geometry would not be conductive to ore genesis. Density‐driven flow systems did not produce focused discharge in the vicinity of the White Pine ore district.
Quantitative basin modeling: present state and future developments towards predictability
Authors: Tuncay K. , Ortoleva P.
Published: January 2004

A critique review of the state of quantitative basin modeling is presented. Over the last 15 years, a number of models are proposed to advance our understanding of basin evolution. However, as of present, most basin models are two dimensional (2‐D) and subject to significant simplifications such as depth‐ or effective stress‐dependent porosity, no stress calculations, isotropic fracture permeability, etc. In this paper, promising areas for future development are identified. The use of extensive data sets to calibrate basin models requires a comprehensive reaction, transport, mechanical (RTM) model in order to generate the synthetic response. An automated approach to integrate comprehensive basin modeling and seismic, well‐log and other type of data is suggested. The approach takes advantage of comprehensive RTM basin modeling to complete an algorithm based on information theory that places basin modeling on a rigorous foundation. Incompleteness in a model can self‐consistently be compensated for by an increase in the amount of observed data used. The method can be used to calibrate the transport, mechanical, or other laws underlying the model. As the procedure is fully automated, the predictions can be continuously updated as new observed data become available. Finally, the procedure makes it possible to augment the model itself as new processes are added in a way that is dictated by the available data. In summary, the automated data/model integration places basin simulation in a novel context of informatics that allows for data to be used to minimize and assess risk in the prediction of reservoir location and characteristics.
Molecular transport of methane, ethane and nitrogen and the influence of diffusion on the chemical and isotopic composition of natural gas accumulations
Authors: Schloemer S. , Krooss B. M.
Published: January 2004

Laboratory experiments have been performed to determine diffusion coefficients of natural gas components (methane, ethane and nitrogen) and isotope fractionation effects under simulated in situ pressure (up to 45 MPa effective stress) and temperature conditions (50–200°C) in water‐saturated pelitic and coarse‐grained rocks. Effective diffusion coefficients of molecular nitrogen (0.39 × 10−11 to 21.6 × 10−11 m2 sec−1 at 90°C) are higher than those for methane (0.18 × 10−11 to 18.2 × 10−11 m2 sec−1 at 90°C). Diffusive flux rates expressed in mass units are generally higher for N2 than for CH4. Both methane and (to a lesser extent) nitrogen diffusion coefficients decrease with increasing total organic carbon (TOC) content of the rock samples because of sorption processes on the organic matter. This effect decreases with increasing temperature. Effective diffusion coefficients increase upon a temperature increase from 50 to 200°C by a factor of four. Effective diffusion coefficients and steady‐state diffusive flux decrease with effective stress. Stationary diffusive fluxes drop by 50–70% for methane and 45–62% for nitrogen while effective diffusion coefficients are reduced by 38% (CH4) and 32–48% (N2), respectively. Isotope fractionation coefficients of diffusive transport are higher for methane (−1.56 and −2.77‰) than for ethane (−0.84 and −1.62‰). Application of the experimental results to geological systems show that diffusive transport has only a low transport efficiency. Significant depletion of natural gas reservoirs by molecular diffusion is only expected in cases of very poor caprock qualities (in terms of thickness and/or porosity) and over extended periods of geological time. Under these circumstances, the chemical and isotopic composition of a gas reservoir will change and maturity estimates based on these parameters may be deceptive. To account for these potential effects, nomograms have been developed to estimate diffusive losses and apply maturity corrections.
Theft by Bandits and Taxation by Kings: A Critique of Mancur Olson on State-Formation
Authors: Höijer Rolf
Published: January 2004

In Power and Prosperity (2000), Mancur Olson argued that bandits who permanently monopolise theft in a given location would limit their own requisitions, protect their victims from theft carried out by others and possibly even provide public goods for their victims. Such stationary and monopolist bandits would effectively transform themselves into autocratic rulers of pristine states. I argue that Olson's ideas do not constitute a satisfactory theory of stateformation for two main reasons. First, kleptocracy, which is a condition of competitive theft, represents an equilibrium according to Olson. So there exists no reason to believe that theft will become monopolised. Second, in Olson's theory, if a monopolist bandit exists, then a monopolist on violence presumably also exists. So having a ‘monopolist on violence’ seems to constitute both ‘cause’ and ‘effect’ in his account. However, if properly revised, his basic insights might nevertheless furnish an important hypothesis from which a more satisfactory theory of state-formation could be constructed.
Use of a Diode Laser Balloon Ablation Catheter to Generate Circumferential Pulmonary Venous Lesions in an Open‐Thoracotomy Caprine Model
Authors: Reddy Vivek Y. , Houghtaling Christopher , Fallon Jay , Fischer Gwen , Farr Norm , Clarke Jamie , Mcintyre Jon , Sinofsky Ed , Ruskin Jeremy N. , Keane David
Published: January 2004

Electrical isolation of the pulmonary veins (PVs) can be curative in certain patients with atrial fibrillation. The ability of a diode laser balloon ablation catheter to isolate PVs was assessed in an open‐thoracotomy caprine model system. After a median sternotomy, the left atrial appendage was cannulated in 19 goats. A laser balloon catheter was placed at the PV ostia and used to deliver photonic energy to the periostial tissue. The applications were delivered at 3.7, 4.5, or 5.4 W/cm for 90–150 seconds. Electrical continuity of the PV with the left atrium was assessed using a multielectrode mapping catheter. After a single application of photonic energy, electrical isolation of the PVs was achieved in (70%) 19/27 PVs. However, the success of electrical PV isolation did not correlate with the dose or duration of the applications. When reflectance spectroscopy was utilized to ensure adequate orientation and contact of the laser balloon catheter with the left atrial myocardium, complete PV isolation was achieved in 5/5 veins at 3.5 W/cm for 120 seconds. Pathological examination revealed no PV stenosis, no pericardial damage, minor lung lesions without pleural perforation, minimal endothelial disruption, and, in the presence of adequate heparinization, no endocardial charring or overlying thrombus. Effective isolation of the PVs can be achieved by delivery of a continuous circular beam of photonic energy to ablate the left atrial ‐ pulmonary venous junction. The use of reflectance spectroscopy to provide real‐time monitoring of the blanching effect of balloon‐tissue contact optimizes lesion delivery. (PACE 2004; 27:52–57)
Radiofrequency Ablation of Atrial Flutter:
Authors: Passman Rod S. , Kadish Alan H. , Dibs Samer R. , Engelstein Erica D. , Goldberger Jeffrey J.
Published: January 2004

Atrial flutter often results from a macroreentrant circuit that uses anatomic structures within the right atrium as its borders. RF ablation at the site of an obligatory isthmus can eliminate the atrial flutter circuit. The aim of this study was to compare two approaches to atrial flutter ablation: the septal (septal aspect of the tricuspid valve annulus to coronary sinus ostium and Eustachian ridge) approach versus the posterior (inferior vena cava to tricuspid valve annulus) approach. Twenty patients were randomized to either the “septal” or “posterior” approach. Entrainment mapping and/or confirmation of bidirectional isthmus conduction at baseline were performed in those patients in atrial flutter and normal sinus rhythm, respectively. RF ablation was performed with standard catheters and techniques. Crossover was permitted after two lines of RF lesions. Endpoints included acute success rates and fluoroscopy times. There was no statistically significant difference in the success rate between the two approaches using intention‐to‐treat analysis. Fluoroscopy times in the septal versus posterior approaches were 58.4 ± 30.3 versus 70.8 ± 31.1 minutes, respectively (P = 0.7). There was more frequent crossover in patients assigned to the septal approach and the one major complication, atrioventricular block, also occurred using this approach. There was no statistically significant difference in the success rate or fluoroscopy times between the septal and posterior approaches to atrial flutter ablation. However, given the risk of atrioventricular block with the septal approach, the posterior approach should be the preferred initial choice. (PACE 2004; 27:83–88)
Cardioverter Defibrillator Implantation in a Child with Isolated Noncompaction of the Ventricular Myocardium and Ventricular Fibrillation
Authors: ÇELIKER ALPAY , KAFALI GÜLDEN , DOĞAN RIZA
Published: January 2004

Isolated noncompaction of the ventricular myocardium is a rare unclassified cardiomyopathy and is thought to be due to arrest of myocardial morphogenesis. In fetal life, it is characterized by an excessively prominent trabecular meshwork and deep intratrabecular recesses, and occurs in the left ventricle in the absence of structural heart disease. Echocardiography provides evidence for the diagnosis. The noncompacted ventricular myocardium may be accompanied by depressed ventricular function, systemic embolism, Wolff‐Parkinson‐White syndrome, left bundle branch block, and ventricular arrhythmia. Although onset of symptoms is frequently delayed until adulthood, symptomatic children have a poor prognosis. In this report, we describe a case of 6‐year‐old girl who had a history of recurrent syncope. Transthoracic echocardiographic examination showed a localized prominent trabeculation and deep intratrabecular recesses at the inferoapical region of the left ventricle. She had several episodes of ventricular fibrillation which was refractory to pharmacological treatment. An implantable cardioverter defibrillator (ICD) was successfully operated three times during follow‐up. (PACE 2004; 27:104–108)
Wolff‐Parkinson‐White Syndrome Concomitant with Asymptomatic Brugada Syndrome
Authors: OHKUBO KIMIE , WATANABE ICHIRO , OKUMURA YASUO , YAMADA TAKESHI , HASHIMOTO KENICHI , MASAKI RIKO , OSHIKAWA NAOHIRO , KOFUNE TATSUYA , WAKITA RIE , TAKAGI YASUHIRO , SAITO SATOSHI , OZAWA YUKIO , KANMATSUSE KATSUO
Published: January 2004

A 29‐year‐old man was referred for electrophysiological testing and radiofrequency ablation because of repeated episodes of palpitation over 2 years. A 12‐lead electrocardiogram during sinus rhythm showed manifest Wolff‐Parkinson‐White syndrome and during palpitation showed narrow QRS tachycardia at a rate of 213 beats/min. Following successful radiofrequency ablation of the left anterolateral accessory pathway, sustained atrial fibrillation was induced by atrial extrastimulation. Cibenzoline (2 mg/kg body weight) was injected to terminate atrial fibrillation. ST‐T segment elevation in the right precordial leads was observed following cibenzoline administration. Ventricular fibrillation was reproducibly induced by ventricular extrastimuli (S1: 600 ms, S2: 220 ms, S3: 210 ms). (PACE 2004; 27:109–111)
Transcutaneous Implantation of an Internal Cardioverter Defibrillator in a Small Infant with Recurrent Myocardial Ischemia and Cardiac Arrest Simulating Sudden Infant Death Syndrome
Authors: GREENE ANNE E. , MOAK JEFFREY P. , RUSSO GREGORY DI , BERGER JOHN T. , HESHMAT YASSER , KUEHL KAREN S.
Published: January 2004

This report describes the implantation of a transcutaneous ICD system using a small patch electrode in the subscapular position, and an active‐can device in a 5.3‐kg infant. The indication for ICD implantation was recurrent cardiac arrest in the presence of normal coronary anatomy. Metabolic evaluation suggested a defect in fatty acid oxidation. (PACE 2004; 27:112–116)
Implantable Cardioverter Defibrillator in a Child Using a Single Subcutaneous Array Lead and an Abdominal Active Can
Authors: LUEDEMANN MONIKA , HUND KARIN , STERTMANN WILHELM , MICHEL‐BEHNKE INA , GONZALES MARIA , AKINTUERK HAKAN , SCHRANZ DIETMAR
Published: January 2004

This report describes the case of an 8‐year‐old boy with hypertrophic cardiomyopathy (HCM) who underwent ICD implantation for recurrent syncope. To avoid vascular complications and to minimize the surgical approach in this small child, a nonthoracotomy ICD system was chosen using a single subcutaneous array lead with only one finger, an abdominally placed active can, and epicardial dual chamber pacing and sensing electrodes. During an 8‐month follow‐up, DFT was confirmed and there were no ventricular tachycardia or complications. It appears to be a safe device for the prevention of sudden cardiac death in infants and small children. (PACE 2004; 27:117–119)
Spontaneous Ventricular Tachycardia and Fibrillation in a Patient with a Positive Microvolt T Wave Alternans Test and Negative Electrophysiological Study
Authors: MOLON GIULIO , MARANGONI DANIELE , BARBIERI ENRICO
Published: January 2004

This report describes a patient with a previous myocardial infarction who presented with syncope. The patient had a positive microvolt T wave alternans test, a negative electrophysiological study, and a normal heart rate variability. In hospital, the patient had episodes of ventricular tachycardia and fibrillation. An implantable cardioverter defibrillator was implanted and during the following week it discharged appropriately. (PACE 2004; 27:120–122)
A Patient with LQTS in Whom Verapamil Administration and Permanent Pacemaker Implantation Were Useful for Preventing Torsade de Pointes
Authors: KOMIYA NORIHIRO , TANAKA KYOEI , DOI YOSHIYUKI , FUKAE SATOKI , NAKAO KOJIRO , ISOMOTO SHOJIRO , SETO SHINJI , YANO KATSUSUKE
Published: January 2004

A 21‐year‐old woman with long QT syndrome and missense mutation in HERG (T613M), suffered from repeated attacks of pause dependent torsade de pointes, even though she was given β‐blockers and underwent stellate ganglion block twice at the age of eight. After she received permanent pacemaker implantation and administration of verapamil, no premature beats or pause dependent torsade de pointes was observed. (PACE 2004; 27:123–124)
Regional bone mineral density after resistive training in young and older men and women
Authors: Ryan Alice S. , Ivey Fred M. , Hurlbut Diane E. , Martel Gregory F. , Lemmer Jeffrey T. , Sorkin John D. , Metter E. Jeffrey , Fleg Jerome L. , Hurley Ben F.
Published: January 2004

Purpose: The purpose of this study was to determine the effects of 6 months of whole‐body resistive training (RT) on total and regional bone mineral density (BMD) and bone mineral content (BMC) by age and gender in young and older men and women.

Methods: Younger men (n=10) and women (n=7) aged 20–29 years (25±1 years) and older men (n=10) and women (n=10) aged 65–74 years (69±1 years) participated in 6 months of progressive whole‐body RT. Upper‐ and lower‐body strength was assessed by the one repetition maximum (1RM) test, and total body fat, lean tissue mass, femoral neck BMD, Ward's triangle BMD, greater trochanter BMD, total‐body BMD, and L2–L4 spine BMD were determined by dual‐energy X‐ray absorptiometry before and after 6 months of RT.

Results: Percent body fat decreased only in the young men (P<0.05). Lean tissue mass increased after training in young men and women and older men (P<0.05) but did not change significantly in older women. Upper‐ and lower‐body 1RM strength increased in all groups (P<0.01). Overall, there was a significant increase in BMD at the femoral neck, ward's triangle and greater trochanter BMD, as well as total body BMC and leg BMC (P<0.05). Total‐body BMD and L2–L4 spine BMD did not change with RT. There were no gender differences in the training response between men and women for any of the BMD regions and no age differences in the training response, except for a trend between young and older subjects for femoral neck (P<0.08).

Conclusion: A 6‐month RT program increases muscle mass and improves BMD of the femoral region in young and healthy older men and women as a group, with a trend for this to be greater in young subjects.
Immuno‐endocrine and metabolic responses to long distance ski racing in world‐class male and female cross‐country skiers
Authors: Rønsen Ola , Børsheim Elisabet , Bahr Roald , Klarlund pedersen Bente , Haug Egil , Kjeldsen‐kragh Jens , Høstmark Arne T.
Published: January 2004

The purpose of this study was to characterize the extent of immune, endocrine, substrate and metabolic changes during a long‐distance cross‐country ski race in extremely well‐trained athletes and evaluate if the blood perturbations would indicate signs of health risk. Ten male (M) and six female (F) national team skiers were investigated as they followed their usual routines of race preparations. Blood samples were drawn before and immediately after a World Cup 50‐km M and 30‐km F ski race with a mean finish time of 142 and 104 min, respectively. Hemoglobin, electrolytes, and C‐reactive protein remained unchanged for both M and F. Serum testosterone remained unchanged in M, but doubled in F. Significant increases were observed in concentrations of granulocytes (F: 5×, M: 5×), natural killer cells (F: 2×, M: 1.5×), adrenaline (F: 12×, M:10×), noradrenaline (F: 7×, M:5×), growth hormone (F: 30×, M: 22×), cortisol (F: 1.5×, M:2×), glucose (F: 2×, M:1.5×), creatine kinase (F: 2×, M:2×), uric acid (F: 1.5×, M: 1.5×) and non‐organic phosphate (F:2×, M:2×), while insulin concentration decreased (F: 0.5×, M: 0.8×). Free fatty acid (FFA) concentration increased (F:2×, M: 3×). In conclusion, we observed substantial changes in several immuno‐endocrine, substrate and metabolic measurements after long distance cross‐country ski racing and suggest that some of these marked changes may reflect the large amount of muscle mass involved during skiing.
Muscle strength correlates with total body bone mineral density in young women but not in men
Authors: Ribom E. , Ljunggren Ö. , Piehl‐aulin K. , Ljunghall S. , Bratteby L.‐E. , Samuelson G. , Mallmin H.
Published: January 2004

Background: Osteoporosis is a growing health problem. One of the proposed reasons for this is a more sedentary lifestyle. The aim of this study was to investigate the associations between muscle strength and total body bone mineral density (TBMD) in young adults at expected peak bone mass.

Methods: Sixty‐four women and 61 men (total 125) 21 years of age were included. Handgrip strength, isokinetic knee‐flexion and ‐extension muscle strength, TBMD, and body composition were measured.

Results: Univariate regression analyses showed that knee flexion and extension explained almost 30% of the variation in TBMD in women, whereas handgrip strength was not associated with TBMD. In men, no correlation between any measures of muscle strength and TBMD was evident.

Stepwise regression analysis showed that knee‐flexion and ‐extension muscle strength in women were associated with TBMD, R2=0.27. In men, lean body mass, fat mass, weight, and height were predictors for TBMD, R2=0.43, whereas muscle strength did not affect the prediction of TBMD.

Conclusions: Muscle strength at weight‐bearing sites is related to TBMD in women, whereas body composition is related to TBMD in men. The association of lower limb strength on TBMD only in young women indicates a gender difference.
Seniors' attitudes: oral health and quality of life
Authors: Penner Audrey , Timmons Vianne
Published: January 2004

Abstract:  The objective of this study was to determine what impact, if any, oral health was having on the quality of life for selected seniors in Prince Edward Island, Canada. The attitudes of seniors towards oral health and its relationship to quality of life is important to define. This self‐reported assessment provides information on this particular relationship. The research design was a random cluster sampling that covered all geographical areas of Prince Edward Island. It represented the cultural diversity within these geographical areas. The survey instrument selected was the Subjective Oral Health Indicators' Status, a validated survey instrument. This particular instrument addressed all the issues raised in the objectives. Data were analysed using Pearson's correlation with age and number of teeth present. The independent t‐test was used to identify differences in responses by gender. Results of the survey showed identification of individual indicators that were having an impact on quality of life. Gender differences in responses were identified in four of the eight subject areas. The level of worry/concern was inconclusive because of the high non‐response rate to the last question. Non‐response rates increased with each topic in the questionnaire. More research is needed to identify clinical needs of seniors on Prince Edward Island. Qualitative study to determine attitudes and beliefs could provide groundwork for future programme design.
Oral manifestations in selective IgA deficiency
Authors: Nikfarjam J , Shahrabi M , Pourpak Z , Nikfarjam L , Kouhkan A , Aghamohammadi A , Moazeni M
Published: January 2004

Abstract: Selective immunoglobulin A (IgA) deficiency is the most common of the primary immunodeficiencies with a frequency of 1/300–1/3000, depending on the screened population. As secretory IgA (SIgA) has a protective role in mucosal surfaces from invasion of microorganisms, it is thought that IgA‐deficient subjects are susceptible to periodontal diseases and oral manifestations. Previous studies show contradictory results, concerning the involvement of the individuals' periodontium with IgA deficiency. The aim of this study was to investigate and compare the oral manifestations in IgA‐deficient subjects with controls. Eleven selective IgA‐deficient subjects aged 3–18 years with serum IgA levels <10 mg dl−1 and 11 age–sex‐matched healthy children as the controls entered the study. Oral mucosal investigation, dental caries, plaque accumulation and periodontal status were assessed. Serum immunoglobulin levels were measured by single radial immunodiffusion (SRID) method. Saliva immunoglobulins and secretory component levels were measured by enzyme linked immunosorbent assay (ELISA) methods. IgA‐deficient patients had serum and saliva IgA levels less than 10 mg dl−1 and 10 µg ml−1, respectively, but other serum immunoglobulin levels were normal and saliva immunoglobulin M (IgM) levels were increased, compared with controls. There were no significant differences in oral manifestations between IgA‐deficient subjects and controls, which may be a result of compensatory increase of saliva IgM or other non‐immunological defence factors in saliva. Thus, it is not necessary to evaluate IgA and SIgA in all the patients with oral and dental lesions and it is thought that it is better to investigate other factors.
Surgical magnification in dental hygiene practice
Authors: Sunell S , Rucker L
Published: January 2004

Abstract:  The potential for improving the occupational health of dental clinicians has expanded as increasingly sophisticated equipment enters the marketplace, yet there has been little improvement to the ergonomics with which dental hygienists operate. The use of surgical magnification has great potential to increase the quality of dental hygiene clinical care and to support the musculoskeletal health of dental hygienists. Although the research evidence to support a relationship between the use of surgical magnification and increased quality of dental hygiene care is extrapolated from parallel studies in dentistry, specific dental hygiene studies suggest that the integration of surgical magnification would be helpful in reducing the incidence of musculoskeletal symptoms experienced by dental hygienists. This is not to suggest that the integration of surgical magnification is a panacea for the musculoskeletal problems experienced by dental hygienists. In fact, improperly selected or adjusted surgical magnification systems can promote positions that place clinicians at increased risk for such problems. Clinicians must first determine the optimal working position that supports their musculoskeletal health and then select magnification systems that will support that position. The working distance, depth of field and optical declination angle of the chosen system must correspond to the musculoskeletal needs of the clinician.
The collaborative practice of dental hygiene
Authors: Reitz M , Jadeja R
Published: January 2004

Abstract:  This paper discusses the collaborative practice of dental hygiene, primarily using examples from California and New Mexico. Several advantages are discussed, including an increased access to all populations and more respect for the field. The earliest roles of a dental hygienist reflect common components of a collaborative practice. Responsibilities of dental hygienists today as educators and preventive dental providers are also tied to this type of practice. Currently, few states in the USA allow such practices; however, benefits are discussed and the positive effects noted. Opposition to these practices exists, although the concerns have not been proven accurate. Collaborative dental hygiene practices are shown to be a positive avenue through which the population can gain access to noted provider shortages, as well as a rewarding option for the field of dental hygiene.
Oral health status in geriatric rehabilitation patients
Authors: Andersson P
Published: January 2004

The aim of this study was to compare the oral health status among patients at a geriatric rehabilitation ward using an oral assessment guide on admission and at discharge. A further aim was to investigate in what respect oral health procedures recommended in the guide were applied when oral health problems were assessed. Registered nurses performed oral health assessments in 107 patients on admission and at discharge. When oral health problems were assessed, oral health procedures were taken. On admission, oral health problems were assessed in 86% of the patients. The corresponding figure at discharge was 51%. The frequency of the problems was significantly lower at discharge than on admission. Oral health procedures were given to 74% of the patients. Recommended oral health procedures were given when problems related to saliva, mucous membranes, gums and teeth/dentures were assessed. In problems related to voice, lips, tongue and swallowing also, other oral health procedures than the recommended were performed. This study demonstrated that the oral health improved during the hospital stay.
Attitudes and opinions of oral health and oral care among community‐dwelling elderly subjects in Sweden: an interview study
Authors: Andersson K
Published: January 2004

Objective: The aim of this study was to investigate attitudes and opinions of old, independently living people about their oral health and how it has affected them through life. Material and methods: A random selection of 12 individuals was made in a group of 79 individuals who earlier participated in a study about self‐reported oral health. The average age was 78.4 years. An interview guide was used as support to focus on oral health. The respondents themselves decided what was important within the topics. The respondents were encouraged to speak freely about their childhood, family, social relations, memories from early dental care, general health situation, experience from health care, life and their future. The interviews were recorded and extended from 60 to 90 min. All of them were transcribed and analysed with phenomenological method inspired by Giogi. The analysis was made by two researchers independently. After 11 interviews, no new information was found; similar opinions, answers and stories recurred. Results: Seven of 11 respondents were born and grown up in the countryside and had moved to Stockholm in the forties. Awareness about dental care was generally low. Many of them have terrible memories from early dental visits, and the dentist was authoritarian and rough. Many had no memories of brushing their teeth as a child. Most of the respondents went to dentists as adults and when they could afford to pay by themselves. After retirement, all have continuous dental care and have visited a dental hygienist during the last 20 years. Nine of 11 have regular contact with a dental hygienist. Most of them are satisfied with their oral health and want to continue being clean and healthy in the mouth. Conclusions: Most of the respondents experienced an improved oral health, information and instructions from the dental hygienist have affected their self‐care. Many tell that they have become more aware and carry out the oral hygiene more carefully after retirement. All of them experience that oral health affects the quality of life.
A simple approach to Anderson localization in one-dimensional disordered lattices
Authors: Domı́nguez-Adame F. , Malyshev V. A.
Published: January 2004

We present a simple approach to Anderson localization in one-dimensional disordered lattices. We introduce the tight-binding model in which one orbital and a single random energy are assigned to each lattice site, and the hopping integrals are constant and restricted to nearest-neighbor sites. The localization of eigenstates is explained by two-parameter scaling arguments. We compare the size scaling of the level spacing in the bare energy spectrum of the quasi-particle (in the ideal lattice) with the size scaling of the renormalized disorder seen by the quasi-particle. The former decreases faster than the latter with increasing system size, giving rise to mixing and to the localization of the bare quasi-particle wave functions in the thermodynamic limit. We also provide a self-consistent calculation of the localization length and show how this length can be obtained from optical absorption spectra for Frenkel excitons.
Nondegenerate normal-mode doublets in vibrating flat circular plates
Authors: Deutsch Bradley M. , Robinson Alexandra R. , Felce Richard J. , Moore Thomas R.
Published: January 2004

The vibrations of flat circular plates have been studied for hundreds of years and are well understood. However, when vibrating circular plates are discussed in textbooks, the relation between pairs of spatially orthogonal vibrational patterns that occur at each of the normal-mode frequencies often is ignored. Usually these orthogonal solutions are presented to the student as being degenerate in frequency. However, in practice the degeneracy of the doublet often is broken, and the two spatially orthogonal solutions are separated in frequency. We show theoretically and experimentally that the degeneracy can be broken by small density perturbations in the plate, and we derive a formula for predicting the magnitude of the frequency splitting. We have used electronic speckle pattern interferometry to investigate the phenomenon of doublet splitting and have confirmed the validity of the theory.
The role of dynamics in the synchronization problem
Authors: Ohanian Hans C.
Published: January 2004

Is Einstein’s procedure for the synchronization of clocks in Special Relativity merely a convention about the one-way speed of light? This issue was first raised in the 1920s by H. Reichenbach, who argued that the standard synchronization involves circular reasoning, and that a nonstandard synchronization convention can be adopted, with unequal values of the speed of light in opposite directions. This “conventionalist thesis” has been widely discussed by physicists and philosophers in the context of kinematics, but not in the context of dynamics. We will show that an examination of the laws of dynamics resolves all ambiguities in synchronization. The nonstandard Reichenbach synchronization introduces pseudoforces into the equation of motion, and these pseudoforces are fingerprints of the nonstandard synchronization, just as the centrifugal and Coriolis pseudoforces are fingerprints of a rotating reference frame. In an inertial reference frame, the nonstandard synchronization is forbidden.
Resolution enhancement by dithering
Authors: Etchenique Roberto , Aliaga J.
Published: January 2004

We show that the uncertainty determined by the minimum division of a measuring instrument can be diminished by using dithering. We present a numerical example to introduce the technique and two experiments that show how the precision is enhanced.
Microwave Bragg diffraction in a model crystal lattice for the undergraduate laboratory
Authors: Cornick M. T. , Field S. B.
Published: January 2004

We describe an undergraduate laboratory experiment in which Bragg diffraction is studied using microwave diffraction from a two-dimensional crystal consisting of a square lattice of metal rods. This apparatus demonstrates the fundamental ideas of the Bragg theory of crystal diffraction using a macroscopic model. Thus, the geometrical relations between the crystal planes and the incoming and scattered wave directions are clearly visible. A key element of the apparatus is a computer interface that allows diffracted intensity measurements at all orientations of crystal and detector. No a priori assumptions need be made concerning the relation between the incident and refracted angles. We also present results of computer simulations of the scattering from our crystal. These simulations have been useful in understanding the differences between the simple Bragg theory and the results from our experiment on a small crystal with finite source and detector distances.
A hint of renormalization
Authors: Delamotte Bertrand
Published: January 2004

An elementary introduction to perturbative renormalization and renormalization group is presented. No prior knowledge of field theory is necessary because we do not refer to a particular physical theory. We are thus able to disentangle what is specific to field theory and what is intrinsic to renormalization. We link the general arguments and results to real phenomena encountered in particle physics and statistical mechanics.
Electrostatics in the presence of dielectrics: The benefits of treating the induced surface charge density directly
Authors: Doerr T. P. , Yu Yi-Kuo
Published: January 2004

A new method is presented for solving electrostatic boundary value problems with dielectrics or conductors and is applied to systems with spherical geometry. The strategy of the method is to treat the induced surface charge density as the variable of the boundary value problem. Because the potential is expressed directly in terms of the induced surface charge density, the potential is automatically continuous at the boundary. The remaining boundary condition produces an algebraic equation for the surface charge density, which when solved leads to the potential. The surface charge method requires the enforcement of only one boundary condition, and produces the induced surface charge in addition to the potential with no additional labor. The surface charge method also can be applied in nonspherical geometries and provides a starting place for efficient numerical solutions.
A well-known boundary value problem requires unusual eigenfunctions
Authors: Sosov Yuriy , Theodosiou Constantine E.
Published: January 2004

The Sturm–Liouville problem for the equation d2X/dx2+λ2X=0 on a closed interval with general unmixed boundary conditions leads to periodic, linear, and exponential eigenfunctions. However, examples of physical situations where different types of these eigenfunctions are employed together in a general solution are difficult to find. We present a physical problem of this type.
A laboratory on the four-point probe technique
Authors: Schuetze Andrew P. , Lewis Wayne , Brown Chris , Geerts Wilhelmus J.
Published: January 2004

We describe how a classic electrostatics experiment can be modified to be a four-point probe lab experiment. Students use the four-point probe technique to investigate how the measured resistance varies as a function of the position of the electrodes with respect to the edge of the sample. By using elementary electromagnetism concepts such as the superposition principle, the continuity equation, the relation between electric field and electric potential, and Ohm’s law, a simple model is derived to describe the four-point probe technique. Although the lab introduces the students to the ideas behind the Laplace equation and the methods of images, advanced mathematics is avoided so that the experiment can be done in trigonometry and algebra based physics courses. In addition, the experiment introduces the students to a standard measurement technique that is widely used in industry and thus provides them with useful hands-on experience.
Grading student problem solutions: The challenge of sending a consistent message
Authors: Henderson Charles , Yerushalmi Edit , Kuo Vince H. , Heller Patricia , Heller Kenneth
Published: January 2004

Grading sends a direct message to students about what is expected in class. However, often there is a gap between the assigned grade and the goals of the instructor. In an interview study of faculty teaching calculus-based introductory physics, we verified that this gap exists and identified three themes that appear to shape grading decisions: (1) a desire to see student reasoning, (2) a reluctance to deduct points from a student solution that might be correct, and (3) a tendency to project correct thought processes onto a student solution. When all three themes were expressed by an instructor, the resulting conflict was resolved by placing the burden of proof on either the instructor or the student. The weighting of the themes with the burden of proof criterion explains our finding that although almost all instructors reported telling students to show their reasoning in problem solutions, about half graded problem solutions in a way that would likely discourage students from showing this reasoning.
Cation site distribution in clinochlores: a NIR approach
Authors: Ferrage E. , Martin F. , Micoud P. , Petit S. , De parseval P. , Beziat D. , Ferret J .
Published: January 2004

A near infrared (NIR) spectroscopy approach was undertaken to collect information on the Al cationic distribution in tetrahedral and octahedral sites in natural chlorite (clinochlore) samples. Structural formulae were established using electron microprobe and Mössbauer spectroscopy. A band located near 7115 cm–1was attributed to the overtone of OH fundamental stretching mode of Mg2AlOH and increases with the total Al amount. Good correlation was obtained between the (SiAl)O–OH vibration band area and tetrahedral Al content, making it easy to partition Al (and thus Fe3+) between octahedral and tetrahedral sites.
Rythmic changes in crystal chemistry of trioctahedral Cr-chlorites and Cr entrapment: a SEM, EM and Raman study
Authors: Prieto A. C. , Boiron M. -C. , Cathelineau M. , Mosser-ruck R. , Lopez J . A. , García C.
Published: January 2004

Back-scattered scanning electron microscopy (SEM) images of Cr-chlorite crystals from Erzerum (Turkey) reveal that the crystals are chemically inhomogeneous and display complex but well defined crystal zoning characterized by growth bands with contrasting chemical features. The chemical zoning has been investigated at the micron scale using an integrated approach, combining BSEM images, in situ chemical analysis by electron microprobe and Raman spectroscopy. Enrichment in Cr, due to octahedral Al substitution, reaches up to 0.7 atoms per half formula, especially in bands where the Mg content is depleted. These substitutions are also depicted at the micron scale on Raman spectra by changes in the v(OH) band intensities and positions that correlate with the Cr content. The Cr-enrichment occurs thus during specific stages of crystal growth, probably in response to changes in the fluid chemistry controlling the relative availability of Cr, Mg and Al in solution.
NMR study of surfactant molecules intercalated in montmorillonite and in silylated montmorillonite
Authors: Grandjean J . , Bujdák J . , Komadel P .
Published: January 2004

13C CP MAS NMR and 29Si MAS NMR were used to characterize silylated montmorillonites and to estimate the extent of the silylation reaction. Indirectly-detected proton relaxation times of the intercalated surfactant were measured in both silylated and non-silylated clay systems to monitor the dynamics of intercalated species. A greater degree of mobility in the silylated montmorillonites was found. The lack of NMR information resulting from paramagnetic interaction brought about by structural Fe(III) ions was considered. The resulting broadening can prevent the estimation of the trans/gauche conformer ratio of the intercalated surfactant alkyl chain.
Geochemical and mineralogical approaches to assessing provenance and deposition of shales: a case study
Authors: Cavalcante F. , Fiore S. , Piccarreta G. , Tateo F.
Published: January 2004

Mineralogical and geochemical studies of Cretaceous segments of Argille Varicolori and Flysch Rosso successions from the southern Apennines allow their provenance and history to be evaluated.

The occurrence of detrital kaolinite and fine-grained Fe-oxyhydroxides, the strong depletion of Na2O, K2O and CaO, and the enrichment in the transition elements document severe alteration in the source areas. Nevertheless, mineralogical and geochemical features able to discriminate the shale families are still preserved. The presence/absence of rock fragments derived from a ‘crystalline’ source, the significant chemical differences as well as the characteristics of clay minerals, discriminate the studied shales. The absence of indications suggestive of mixing of the detrital components favour the hypothesis that the two shales were deposited in distinct basins which probably received contributions from continent-ocean convergent areas (Argille Varicolori) and from more stable areas (Flysch Rosso).
Pyrometamorphic breakdown of cordierite - muscovite intergrowths
Authors: Grapes R. H.
Published: January 2004

Backscattered electron imaging of cordierite-muscovite intergrowths near the margin of a schist xenolith in trachytic tephra of the Wehr Volcano, East Eifel area, Germany, show that they have undergone disequilibrium melting to form spinel + biotite + sillimanite/?mullite + peraluminous melt. Textures indicate that in the initial stage of reaction, spinel, biotite and sillimanite/?mullite formed with melt produced in cordierite and spinel + ?mullite with melt after muscovite, providing evidence of two different reaction pathways. Fe-Mg distributions between biotite/spinel, cordierite/spinel, cordierite/ biotite suggest a melting temperature of ∼770°C, implying overstepping of various calculated and experimentally determined mineral breakdown curves of between 30 and 170°C during short-term heating before the xenolith was quenched on eruption.
Potassic glass and calcite carbonatite in lapilli from extrusive carbonatites at Rangwa Caldera Complex, Kenya
Authors: Rosatelli G. , Wall F. , Le Bas M. J.
Published: January 2004

The ∽16 Ma Rangwa Caldera Complex, part of the large Kisingiri nephelinite-carbonatite volcano, Homa Bay District, western Kenya (0º34’S; 34º09’E) contains carbonatitic lapilli and ash tuffs, agglomerate and tuffisite, and a number of intrusive calcite carbonatites. A detailed petrographic and electron microprobe study has been performed on 20 fresh samples from the collection at The Natural History Museum, London.

Most of the juvenile lapilli and ash particles are either predominantly composed of devitrified silicate glass (now biotite/phlogopite but probably also originally potassic silicate) or calcite carbonatite, which suggests that two molten liquids were erupted simultaneously. Some 10 mm-diameter lapilli contain quench-textured calcite crystals set in devitrified glass. They are interpreted as having crystallized from a molten silicate-carbonate melt at, or very near, the surface.

The extrusive carbonate is mostly composed of calcite, consistent with intrusive calcite compositions at Rangwa. Other key minerals are magnetite, two types of mica (magnesian-biotite phenocrysts and phlogopite xenocrysts) and fluorapatite.

The pyroclastic rocks contain many calcite carbonatite clasts, and fragments of calcite, aegirine and diopside, fluorapatite, magnetite, plus some phlogopite, titanite, K-feldspar, fenite and glimmerite; ijolite lithics are rare. Thus, there is no evidence for a cognate nephelinitic (ijolitic) or melilitic magma nor evidence for a direct relationship with the nephelinites of the Kisingiri volcano.

Two hypotheses are discussed. A rising silicate and K-rich carbonatite liquid may have evolved towards a carbonate-rich K-silicate liquid after crystallization of calcite, phlogopite, apatite and magnetite. Preservation of the the potassic component may be rare, with a more usual scenario being that potassic component separates as fenitizing fluids. The alternative is that the silicate component is remobilized fenite, formed from country rock that was mobilized by supercritical K-rich, fenitizing fluids associated with the carbonatite. Both scenarios require generation of a K-rich carbonatite magma, probably from a carbonated phlogopite-rich metasomatized mantle.