bluuebunny/crossref_metadata_2025 huggingface dataset:
Ignorance is bliss? HIV and moral duties and legal duties to forewarn
Authors: Bennett Rebecca , Draper Heather , Frith Lucy
Published: July 2002

In 1997, a court in Cyprus jailed Pavlos Georgiou for fifteen months for knowingly infecting a British woman, Janet Pink, with HIV-1 through unprotected sexual intercourse. Pink met Georgiou in January 1994 whilst on holiday. She discovered that she had contracted the virus from him in October 1994 but continued the relationship until July 1996 when she developed AIDS. She returned to the UK for treatment and reported Georgiou to the Cypriot authorities.1

There have been a number of legal cases involving deliberate transmission of HIV, but most have involved forced exposure to infected bodily fluids for example, rape or biting, and have been dealt with using the existing legislation for rape or assault. While it is often difficult to prove responsibility for transmission in cases of forced exposure to HIV, it is even more contentious in cases like those of Janet Pink where an individual has consented to sex but claims that he/she was not forewarned of his/herpartner's HIV-positive status. At present there is no specific criminal offence of having unprotected sexual intercourse without disclosing one's HIV-positive status but a prosecution could possibly be brought under any one of a number of existing offences.2Perhaps a change of policy needs to be considered. The Home Office has issued a consultation document which outlines a proposal that will allow the criminalisation of intentional transmission of diseases, like HIV, that are likely to cause serious harm. This revised legislation would cover all other potentially fatal diseases (including salmonella and legionnaire's disease, for instance) but seems primarily to be targeted at HIV transmission. Should transmission of HIV through consensual sex, without the HIV-positive status of the individual being disclosed, be an offence? This question, and that of whether there is a moral obligation to disclose a positive HIV status prior to having a sexual relationship is the subject of this paper.
Evaluation of research ethics committees in Turkey
Authors: Arda Berna
Published: July 2002

In Turkey, there was no legal regulation of research on human beings until 1993. In that year “the amendment relating to drug researches” was issued. The main objectives of the regulation are to establish a central ethics committee and local ethics committees, and to provide administrative control.There are no compulsory clinical ethics lectures in the medical curriculum, so it is also proposed that research ethics committees (RECs) play a central educational role by helping physicians to be aware of moral problems and by contributing to the training of research teams.
Short term exposure to airborne microbial agents during farm work: exposure-response relations with eye and respiratory symptoms
Authors: Eduard W , Douwes J , Mehl R , Heederik D , Melbostad E
Published: July 2002

OBJECTIVES

Exposure to high levels of non-infectious microbial agents is recognised as a cause of respiratory disease in working populations, but except for endotoxins, little is known about exposure-response relations. As these effects do not depend on viability, exposure to non-viable microbial agents is important. Various methods not based on microbial cultures were explored to study the complex microbial exposure of farmers and associations with acute symptoms during work.

METHODS

Airborne exposure was measured when farmers carried out specific tasks. Fungal spores, bacteria, endotoxins, β(1→3)-glucans, fungal antigens specific forPenicilliumandAspergillusspecies, and mites were measured by methods not based on microbial cultures. Also silica, inorganic and organic dust, ammonia, hydrogen sulphide, and nitrogen dioxide were measured. Respiratory, and nose and eye symptoms experienced during measurements were recorded by a short questionnaire. Both univariate and multivariate statistical analyses were applied to assess the relations between exposure and acute symptoms.

RESULTS

106 Farmers and their spouses participated in this study. Prevalences of work related symptoms were: wheezing 3%; chest tightness 7%; cough 14%; eye symptoms 18%; and nose symptoms 22%. Prevalence ratios for nose and eye symptoms were 4–8 after exposure to 20–500×103fungal spores/m3and higher, and a prevalence ratio for cough was 4 after exposure to 500–17 000×103fungal spores/m3. Nose symptoms were also associated with exposure to silica with prevalence ratios of 4–6 after exposure to 0.015–0.075 mg /m3and higher.

CONCLUSIONS

Farmers had a high occurrence of symptoms of the nose and eyes as well as cough during work. These symptoms were associated in a dose dependent manner with exposure to fungal spores. Nose symptoms were also associated with exposure to silica.
Sickness absence in hospital physicians: 2 year follow up study on determinants
Authors: Kivimäki M , Sutinen R , Elovainio M , Vahtera J , Räsänen K , Töyry S , Ferrie J E , Firth-Cozens J
Published: July 2002

OBJECTIVES

To identify determinants of sickness absence in hospital physicians.

METHODS

The Poisson regression analyses of short (1–3 days) and long (>3 days) recorded spells of sickness absence relating to potential determinants of sickness absence were based on a 2 year follow up period and cohorts of 447 (251 male and 196 female) physicians and 466 controls (female head nurses and ward sisters).

RESULTS

There were no differences in health outcomes, self rated health status, prevalence of chronic illness, and being a case on the general health questionnaire (GHQ), between the groups but physicians took one third to a half the sick leave of controls. All the health outcomes were strongly associated with sickness absence in both groups. Of work related factors, teamwork had the greatest effect on sickness absence in physicians but not in the controls. Physicians working in poorly functioning teams were at 1.8 (95% confidence interval (95% CI) 1.3 to 3.0) times greater risk of taking long spells than physicians working in well functioning teams. Risks related to overload, heavy on call responsibility, poor job control, social circumstances outside the workplace, and health behaviours were smaller.

CONCLUSION

This is the first study of hospital physicians to show the association between recorded sickness absence and factors across various areas of life. In this occupational group, sickness absence is strongly associated with health problems, and the threshold for taking sick leave is high. Poor teamwork seems to contribute to the sickness absenteeism of hospital physicians even more than traditional psychosocial risks—such as overload and low job control. These findings may have implications for training and health promotion in hospitals.
Effects on the nervous system in different groups of workers exposed to aluminium
Authors: Iregren A , Sjögren B , Gustafsson K , Hagman M , Nylén L , Frech W , Andersson M , Ljunggren K G , Wennberg A
Published: July 2002

OBJECTIVE

To investigate possible neurotoxic effects in groups of aluminium pot room and foundry workers, aluminium welders, and a small group of workers exposed to aluminium in the production of flake powder.

METHODS

Exposure to aluminium was evaluated with aluminium concentrations in blood and urine as well as a questionnaire. The groups exposed to aluminium were compared with a group of mild steel welders. Neurotoxic effects were studied with mood and symptom questionnaires and several psychological and neurophysiological tests.

RESULTS

The pot room and foundry workers showed very low aluminium uptake as their aluminium concentrations in blood and urine were close to normal, and no effects on the nervous system were detected. The group of workers exposed to flake powder had high concentrations of aluminium in blood and urine, even higher than those of the aluminium welders. However, aluminium could not be shown to affect the functioning of the nervous system in flake powder producers. Although significant effects could not be shown in the present analysis of the data on welders, the performance of the welders exposed to high concentrations of aluminium was affected according to the analyses in the original paper from this group.

CONCLUSIONS

For the pot room and foundry workers no effects related to the exposure to aluminium could be found. For the group of flake powder producers exposed for a short term no effects on the nervous systems were evident despite high levels of exposure. Due to the high concentrations of aluminium in the biological samples of this group, measures to reduce the exposure to aluminium are recommended, as effects on the central nervous system might develop after protracted exposures. However, this assumption needs to be verified in further studies.
Upper airway inflammation and respiratory symptoms in domestic waste collectors
Authors: Wouters I M , Hilhorst S K M , Kleppe P , Doekes G , Douwes J , Peretz C , Heederik D
Published: July 2002

Objectives: To compare respiratory symptoms and upper airway inflammation in domestic waste collectors and controls, and to find the association between measures of upper airway inflammation on the one hand and exposure concentrations of organic dust or respiratory symptoms on the other hand.

Methods: In a cross sectional study among 47 waste collectors and 15 controls, questionnaire data on respiratory symptoms were collected. Nasal lavage (NAL), to assess upper airway inflammation, was performed before and after a work shift at the beginning and at the end of the working week. In NAL fluid, cells were counted and differentiated and concentrations of interleukin 6 (IL6), IL8, tumour necrosis factor-α (TNFα), and IL1β were measured. In collectors, inhalable dust samples were collected in which bacterial endotoxin and mould β(1→3)-glucan were assessed.

Results: Prevalence of respiratory symptoms was higher in waste collectors than in controls. Geometric mean exposure concentrations were 0.58 mg/m3for dust, 39 EU/m3for endotoxin, and 1.3 μg/m3for β(1→3)-glucan. At the end of the week collectors had higher concentrations of total cells and IL8 in NAL before and after a shift than controls (cells, before 1.9-fold p<0.10, after 3.3-fold p<0.01; IL8, before and after 1.8-fold p<0.05), and after/before work shift ratios of total cells were also higher (2.3-fold p=0.06) in collectors than in controls. Cells in NAL fluid consisted predominantly of neutrophils and epithelial cells, whereas eosinophils and mononuclear cells were rarely found. Exposure to dust and endotoxin was associated with concentrations of IL8 after the shift (p<0.05). Increased concentrations of IL8 (p<0.05) and total cells (p<0.10) after the shift were associated with respiratory symptoms. Concentrations of IL6, TNFα, and IL1β were not associated with waste collecting, symptoms, or exposure.

Conclusions: Waste collectors show signs of increased upper airway inflammation and respiratory symptoms compared with controls. Exposure to organic dust probably underlies the inflammation mediated by neutrophils that result in respiratory symptoms.
Suicide mortality among electricians in the Swedish construction industry: Table 1
Authors: Järvholm B , Stenberg A
Published: July 2002

Objectives: To investigate the risk of suicide in Swedish electricians employed in the construction industry. A few studies have indicated an increased risk of suicide for electricians in the construction industry and electricians exposed to electromagnetic fields.

Methods: This is a cohort study. Electricians were identified through a computerised register of construction workers who had participated in health examinations in 1971–92. In this register, 33 719 male electricians were identified together with a reference group consisting of 72 653 male glass or woodworkers. Through a linkage with the Swedish Death Register, the cause of death was identified to the end of 1997. Mortality as a result of suicide was also compared with the general population with adjustments for sex, age, and period.

Results: The risk of mortality from suicide was decreased for electricians (standardised mortality ratio (SMR) 0.58, 95% confidence interval (95% CI) 0.47 to 0.71) and for the reference group of construction workers (SMR 0.81, 95% CI 0.72 to 0.91) compared with the general population.

Conclusion: Contrary to some other studies, risk of suicide was not increased among electricians in the construction industry.
Updated epidemiological study of workers at two California petroleum refineries, 1950–95
Authors: Satin K P , Bailey W J , Newton K L , Ross A Y , Wong O
Published: July 2002

Objectives: To further assess the potential role of occupational exposures on mortality, a second update of a cohort study of workers at two petroleum refineries in California was undertaken.

Methods: Mortality analyses were based on standardised mortality ratios (SMRs) and 95% confidence intervals (95% CIs) using the general population of California as a reference. Additional analyses of lymphatic and haematopoietic cancer deaths and diseases related to asbestos were undertaken.

Results: The update consisted of 18 512 employees, who contributed 456 425 person-years of observation between 1950 and 1995. Both overall mortality and total cancer mortality were significantly lower than expected, as were several site specific cancers and non-malignant diseases. In particular, no significant increases were reported for leukaemia cell types or non-Hodgkin's lymphoma. Mortality excess from multiple myeloma was marginally significant. The excess was confined to employees enrolled before 1949. Furthermore, there was no significant upward trend based on duration of employment, which argues against a causal interpretation relative to employment or exposures at the refineries. No increase was found for diseases related to asbestos: pulmonary fibrosis; lung cancer; or malignant mesothelioma. There was no significant increase in mortality from any other cancers or non-malignant diseases.

Conclusion: This second update provides additional reassurance that employment at these two refineries is not associated with increased risk of mortality.
The impact of hearing on communication
Authors: Fook Lisa , Morgan Rosemary , Sharma Priya , Adekoke Abel , Turnbull Christopher J
Published: July 2002

The study was designed to assess the impact of hearing impairment on communication between older hospital patients and medical staff and to see whether intervention to improve hearing influences perceived communication. Structured interviews were held with 200 mentally alert elderly hospital in-patients before and after the introduction of voice amplifiers and acetate cards depicting a hearing problem. Prior to intervention 22% of patients rated communication with their doctor as poor or unsatisfactory. Following intervention there was a significant improvement (Chi-square p=0.006), with only 6% of patients reporting communication with their doctor as poor or unsatisfactory. Most of the patients who felt communication was unsatisfactory could not hear what was being said. We conclude that simple measures can improve the number of older patients hearing what their doctor says and improve their perception of communication with the hospital doctor.
Primary neuroleptospirosis
Authors: Panicker J N , Mammachan R , Jayakumar R V
Published: July 2002

Leptospirosis is an important zoonosis of worldwide distribution. It is uncommon for leptospirosis to present as a primary neurological disease. In this study of patients who presented with an acute neurological disease, and who were subsequently found to have leptospirosis, aseptic meningitis was the commonest manifestation. The other presentations were myeloradiculopathy, myelopathy, Guillain-Barré syndrome-like presentation, meningoencephalitis, intracerebral bleed, cerebellar dysfunction, iridocyclitis, and tremor/rigidity. Treatment consists of antibiotics, crystalline penicillin being the drug of choice, which reduces the course of illness if given early. The role of steroids is controversial. The prognosis after primary neuroleptospirosis is generally good but altered sensorium and seizures herald a worse prognosis.
Acute myocardial infarction in young adults: causes and management
Authors: Osula S , Bell G M , Hornung R S
Published: July 2002

The case report in this review illustrates an acute myocardial infarction in a young adult probably due to arterial thrombosis that can be attributed to a hypercoagulable state resulting from the nephrotic syndrome. Although rare, acute myocardial infarction should be considered in young adults presenting with chest pain. A detailed clinical history may help to identify the aetiology, and guide subsequent management, but diagnostic coronary angiography is essential. Careful risk factor modification and treatment of the underlying cause should reduce the incidence of recurrent cardiac events.
Plain abdominal radiographs in acute medical emergencies: an abused investigation?
Authors: Feyler S , Williamson V , King D
Published: July 2002

Plain abdominal radiographs are commonly requested for acute medical emergencies on patients with non-specific abdominal symptoms and signs. In this study 131 plain abdominal radiographs performed on the day of admission were prospectively analysed. In only 16 cases (12%) the reasons for requests conformed to the recommended guidelines by the Royal College of Radiologists. The reason for the request was stated in the case notes in only three cases. In 62 cases (47%), there was no comment made on the film by the requesting clinician. There was a discrepancy in the interpretation of the radiograph between the clinician and the radiologist in 31 cases (24%). The clinical management was influenced by plain abdominal radiographs in only nine cases (7%). The majority of plain abdominal radiographs requested on acute medical emergencies is inappropriate. There is a need to ensure guidelines are followed to prevent unnecessary exposure of patients to radiation as well as preventing expenditure on irrelevant investigations.
Breath analysis to detect recent exposure to carbon monoxide
Authors: Cunnington A J , Hormbrey P
Published: July 2002

Objectives

To determine the normal range for carbon monoxide concentrations in the exhaled breath of subjects in the emergency department and to develop a protocol for the use of a breath analyser to detect abnormal carbon monoxide exposure.

Methods

A hand held breath analyser was used to measure end expiratory carbon monoxide concentrations in 382 consenting subjects. Questionnaire data were collected to assess the effect of common sources of carbon monoxide exposure on breath carbon monoxide levels. Smokers were used as a carbon monoxide exposed group for comparison with non-smokers.

Results

The range of carbon monoxide concentrations obtained in the non-smoking group was 0–6 ppm and in the smoking group was 1–68 ppm. Smokers had a mean breath carbon monoxide concentration of 16.4 ppm and non-smokers had a mean of 1.26 ppm (95% confidence interval (CI) for difference 13.6 to 16.8 ppm). Male sex and frequent motor vehicle use were associated with slightly higher carbon monoxide concentrations (by 0.40, 95% CI 0.18 to 0.63 ppm, and 0.38, 95% CI 0.13 to 0.63 ppm, respectively) in the non-smoking group. Mean breath carbon monoxide concentrations increased in direct proportion to the number of cigarettes smoked (p<0.001) and there was a negative correlation between carbon monoxide and time since last smoking a cigarette (p<0.001). Altogether 23% of smokers had breath carbon monoxide concentrations in the range 1–6 ppm.

Conclusions

Breath analysis was rapid and results correlated well with carbon monoxide exposure. In this population subjects with breath carbon monoxide concentrations greater than 6 ppm should be assessed for the risk of carbon monoxide poisoning. However even carbon monoxide concentrations less than 6 ppm do not exclude carbon monoxide poisoning within the last 24 hours.
A three year prospective audit of 212 presentations to the emergency department after electrical injury with a management protocol
Authors: Blackwell N , Hayllar J
Published: July 2002

Significant numbers of presentations to the emergency department were found to relate to low voltage electrical injury, for which there was no widely accepted management protocol. It was decided to examine the outcome of patients after low voltage electrical injury with particular reference to electrocardiogram (ECG) changes and to evaluate a protocol for managing these injuries in order to optimise the management of patients after electrical injury. A prospective observational study was done over three years of 212 consecutive presentations to the emergency department of Mount Isa Base Hospital with a four year follow up after implementation of the revised protocol. In 4% of patients, early transient conduction abnormalities were seen after low voltage electrical injury. Admissions for cardiac monitoring were reduced dramatically with no resultant ill effects. Asymptomatic patients with a normal ECG on presentation do not need ECG monitoring after low voltage electrical injury. Patients with significant symptoms or ECG changes should be admitted for monitoring and observation. In view of the high proportion of workplace related injuries occupational health measures such as “triple gloving” should be mandatory for high risk groups.
Knowledge of aspects of acute care in trainee doctors
Authors: Smith G B , Poplett N
Published: July 2002

Deficiencies in trainees’ knowledge, skills, and attitudes have the potential to influence the initial assessment, treatment, and outcome of acutely ill ward patients. Knowledge of basic aspects of acute care were assessed among a group of 185 trainee doctors at six hospitals. Many were unaware of the signs of total airway obstruction, confusing them with those of partial obstruction (pre-registration house officers (PRHOs) 11%, senior house officers (SHOs) 14%) or apnoea (PRHOs 47%, SHOs 26%). Knowledge about the use of non-rebreathing oxygen masks was poor; 23% of trainees could not describe the purpose of the reservoir bag or gave answers that were unclear or incorrect. Seven trainees thought that it was involved in humidification, or carbon dioxide collection or removal. Seventeen per cent of trainees could not quote the maximum deliverable inspired oxygen concentration provided by these masks or gave values below the normal range. Thirty one per cent of trainees thought that the lower end of the normal range for pulse oximetry (SpO2) was below 95%; nine (5%) believed it to be below 90%. There was also poor knowledge of the factors influencing the function of a pulse oximeter. Similar deficits in knowledge and understanding existed in relation to the normal capillary refill time, minimum hourly urine output, the use of the AVPU scale and the role of blood glucose testing in unconscious adults. Only 22% of PRHOs and 21% of SHOs identified the correct percentage hospital survival for patients who suffer an in-hospital cardiac arrest. Knowledge of aspects of consent was unsatisfactory. It is recommended that all medical schools urgently incorporate training about common aspects of “generic” acute care in their curricula.
Integrated teleseismic studies of the southern Alberta upper mantle
Authors: Shragge J , Bostock M G , Bank C G , Ellis R M
Published: July 2002

This paper presents results from a teleseismic experiment conducted across the Hearne Province in south-central Alberta. Data from an array of nine portable broad-band seismographs deployed along a 500 km NWSE array have been supplemented with recordings from two Canadian National Seismograph Network stations. P-wave delay times from 293 earthquakes have been inverted for upper-mantle velocity structure below the array. The recovered model reveals high velocities beneath much of the southern Hearne Province to depths of 200250 km, which are interpreted as deep-seated lithospheric structure. Contrary to recent tectonic models, these results suggest that the Hearne lithosphere has remained intact. In particular, it appears unlikely that evidence for extensive, lower crustal melting derives from lithospheric delamination. However, the results admit the possibility that high mantle conductivity, as revealed in magnetotelluric studies, originates through small volumes of connected hydrous minerals or other conductive species introduced during subduction. Decreased upper-mantle velocities at the northern end of the Medicine Hat block also pose challenges for the interpretation of differential subsidence across the region which may manifest distant forcing due to more recent subduction. Multievent SKS-splitting analysis yields an average polarization direction that is broadly consistent with both the orientation of fossil strain fields, related to ~ 1.8 Ga NWSE shortening, and North American absolute plate motion. Moho depth estimates from receiver functions are fairly uniform (~ 38 km) beneath northern stations but show crustal thickening (>40 km) within the Medicine Hat block to the south and are consistent with values from active-source profiling.
Synthesis of the toxicological impacts of theExxon Valdezoil spill on Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, U.S.A.
Authors: Carls M G , Marty G D , Hose J E
Published: July 2002

Pacific herring (Clupea pallasi) in Prince William Sound (PWS) were affected by two major events in the past decade: the Exxon Valdez oil spill in 1989 and a 75% collapse in the adult population in 1993. In this review we compare and reinterpret published data from industry and government sources. Combining site-specific estimates of exposure and recent laboratory effects thresholds, 0.40.7 µg·L1total polynuclear aromatic hydrocarbons, we conclude that 2532% of the embryos were damaged in PWS in 1989. Significant effects extended beyond those predicted by visual observation of oiling and by toxicity information available in 1989. Oil-induced mortality probably reduced recruitment of the 1989 year class into the fishery, but was impossible to quantify because recruitment was generally low in other Alaskan herring stocks. Significant adult mortality was not observed in 1989; biomass remained high through 1992 but declined precipitously in winter 19921993. The collapse was likely caused by high population size, disease, and suboptimal nutrition, but indirect links to the spill cannot be ruled out. These concepts have broad application to future oil spill assessments. For example, safety standards for dissolved aromatics should reflect the previously unrecognized high toxicity of polynuclear aromatic hydrocarbons to adequately protect critical life stages.
Bid preparation for earthmoving operations
Authors: Marzouk Mohamed , Moselhi Osama
Published: July 2002

This paper presents a computer system developed to assist earthmoving contractors in preparing proposals. It can also be used by owners and (or) their agents to plan and estimate the cost and duration of earthmoving projects. This is particularly useful for large projects where owners need to define a feasible scope of work that suits their budgets and operating plans. The system has been developed utilizing computer simulation. This paper provides an overview of the developed system and briefly describes its basic components, focusing primarily on the development of the system's database and the procedure used to account for indirect cost components of this class of projects. The paper also demonstrates the capabilities of the developed system in selecting most-suitable equipment fleets, from available equipment, that meet the terms and conditions outlined in bid documents. A project example is analyzed to demonstrate the essential features of the developed system.Key words: bid preparation, earthmoving, equipment database, indirect cost, computer simulation.
A study of laminar flow in low aspect ratio lid-driven cavities
Authors: Yang Y , Straatman A G , Martinuzzi R J , Yanful E K
Published: July 2002

The evolution to fully developed laminar flow in low aspect ratio, two-dimensional, lid-driven cavities has been studied experimentally and numerically. Velocity measurements were made in water in a moving-lid apparatus using a laser Doppler velocimeter (LDV). Numerical solutions for the cavity flow were obtained by solving the two-dimensional mass-momentum equation set in a finite-volume framework. The measured and predicted results were in excellent agreement. Fully developed cavity flow is said to exist when the main regions of the flow field become independent of the aspect ratio. When fully developed conditions prevail, a region of countercurrent flow (CCF) separates the end structures, which are decoupled. The extent of the end regions is shown to grow linearly with increasing Reynolds number Re, based on the lid speed and the cavity height. Consequently, the critical aspect ratio for the onset of fully developed flow is also linearly dependent on Re. Above a critical Reynolds number, Re [Formula: see text] 300, the flow becomes unsteady, and a lower-wall, tertiary vortex appears, which is thought to be associated with the onset of hydrodynamic instability.Key words: lid-driven cavity, laminar flow, shallow water cover, countercurrent flow.
1-Propanol hydrate by IR spectroscopy
Authors: Max Jean-Joseph , Daneault Stéphane , Chapados Camille
Published: July 2002

The mid-IR attenuated total reflectance (mid-IRATR) spectra of a series of 1-propanol and water mixtures were obtained. Factor analysis (FA) applied to spectra gave the spectra of three principal species and their abundance: pure water, pure propanol, and a 1-propanol hydrate (1:1). When compared to the pure solvents, the hydrate propanol bands were modified which indicated that the valence bonds were perturbed. The assignment of the hydrate IR bands was made by comparing them with those of pure 1-propanol and pure water. No monomer was observed which indicated that all species were associated. The simplest representation of the different associations is by groups of two on which an intermolecular bond (H-bond) can be placed. The exchange between the molecules can be represented by the following equation: (H2O···H2O) + (CH3CH2CH2OH···OHCH2CH2CH3) [Formula: see text] 2(CH3CH2CH2OH···OH2). The hydrate's formation constant (Kf) is 1.2 (±0.2). This value is less than the one expected from the association of freely moving molecules, indicating that the hydrophobic interactions of the 1-propanol aliphatic chains decrease the strength of the hydrogen bond between water and alcohol in the hydrate.Key words: IR spectroscopy, ATR spectroscopy, 1-propanol, liquid, aqueous solutions, eigenspectra, hydrate, factor analysis.
Examination of adhesive determinants in three species ofLactobacillusisolated from chicken
Authors: Gusils C , Cuozzo S , Sesma F , González S
Published: July 2002

The microbial adhesion process includes passive forces; electrostatic interactions; hydrophobic, steric forces; lipoteichoic acids; and specific structures, such as external appendages (lectins) and (or) extracellular polymers. In a previous work, we showed that Lactobacillus animalis, L. fermentum, and L. fermentum ssp. cellobiosus had lectinlike proteic structures on their surfaces and high hydrophobicity values on the cell surface of L. fermentum ssp. cellobiosus. Here, we examined the presence of the bacterial forces or structures that could be involved in the interaction between bacteria and epithelial cells. Lactobacillus animalis and L. fermentum possessed a net negative surface charge, whereas L. fermentum ssp. cellobiosus showed similar affinity to both cationic and anionic exchange resins, aggregated in the presence of ammonium sulfate, and had high affinity (75.4%) to a hydrophobic matrix. Only L. animalis was shown to have ribitol teichoic acids in the cell wall. The amount of polysaccharides from cell walls varied between different strains, with L. fermentum ssp. cellobiosus having the highest concentration. Lectin extracts obtained from lactobacilli did not possess sugar residues, thereby demonstrating the proteic nature of the superficial surface structures of three strains. The lactic acid bacteria studied here showed different surface determinants, which could be involved in the interactions between these lactobacilli and intestinal epithelial cells.Key words: adhesion, lactobacilli, probiotics, chickens.
Understory succession and the gap regeneration cycle in a Tsuga canadensis forest
Authors: Rankin W T , Tramer Elliot J
Published: July 2002

We examined understory succession in current and former canopy gaps in mature Tsuga canadensis (L.) Carrière forests in southeastern Ohio. First, we reconstructed understory succession in current gaps by sampling 28 gaps ranging from 0 to 9 years. Second, we reconstructed the gap history of a single Tsuga community by clustering release events evident in the growth rings of 156 trees. The two reconstructions formed an 80-year chronosequence, allowing us to examine both short-term effects of gaps as well as long-term effects of closed-canopy conditions on eight common understory species. Understory cover was highest in canopy gaps. All eight understory species in the study exhibited higher cover in canopy gaps than beneath the closed Tsuga canopy. In addition, one species increased percent biomass allocated towards shoots. Although most species increased cover in gaps, different species reached peak cover at different times during gap succession. Understory species reaching peak cover early in the life of the gap were also present beneath the closed canopy and invested primarily in lateral biomass. Understory species reaching peak cover late in the life of the gap, however, were confined to gaps and invested primarily in vertical biomass. Understory cover declined during gap closure; this decline was most pronounced 20 years following gap formation. Thereafter, total understory cover increased slightly, although never to gap levels.
Fourteen-year growth response of young lodgepole pine to repeated fertilization
Authors: Kishchuk Barbara E , Weetman Gordon F , Brockley Robert P , Prescott Cindy E
Published: July 2002

Four rates of N (0, 50, 100, and 150 kg·ha1) with and without a fertilizer mix containing P, K, S, Ca, Mg, and micronutrients were applied to a stand of 8-year-old lodgepole pine (Pinus contorta var. latifolia Engelm.) in four applications during 7 years. Fourteen years after the first fertilization, mean tree basal area and volume were significantly increased in the treatments containing the two highest rates of N plus the fertilizer mix. Mean tree basal area was 38% greater and mean tree volume was 42% greater in the highest N (525 kg·ha1) plus mix treatment than in the control treatment. Stand basal area increased 48% over the control in the highest N plus mix treatment. Mean tree basal area and volume were 27 and 25% greater than the control under the intermediate N rate (350 kg·ha1) with mix, respectively. Height growth was not significantly increased by fertilization. Both higher rates of N (four applications of >100 kg·ha1) and the fertilizer mix were required for significant growth responses to occur. Addition of N alone or mix alone had a negative effect on mean tree basal area and volume. Addition of higher N rates without the mix decreased foliar total S and SO4-S concentration and increased the N/S ratio. Addition of the higher rates of N without the mix aggravated slight K deficiencies. The responses to the higher N rates in combination with the fertilizer mix are mainly attributable to S.
Potential carry-over of seeds from 11 common shrub and vine competitors of loblolly and shortleaf pines
Authors: Shelton Michael G , Cain Michael D
Published: July 2002

Many of the competitors of the regeneration of loblolly and shortleaf pines (Pinus taeda L. and Pinus echinata Mill., respectively) develop from seed disseminated on the site after reproduction cutting or from the seed bank. To evaluate the potential carry-over of the seeds from 11 shrub and vine competitors of these two important southern pines, we designed packets so that fruits could be deposited on the forest floor and subsequently extracted over a 3-year period. After extraction, repeated cycles of 60 days of germination testing followed by 60 days of stratification were conducted over a maximum of 42 months to determine the potential for seed carry-over and the germination characteristics of the species. Seeds of privet (Ligustrum vulgare L.) showed no viability after the first winter of field storage, while seeds of rattan vine (Berchemia scandens (Hill) K. Koch) and Japanese honeysuckle (Lonicera japonica Thunb.) had low viability (13%) after the third year. In contrast, seeds of smooth sumac (Rhus glabra L.), devils-walkingstick (Aralia spinosa L.), pepper vine (Ampelopsis arborea (L.) Koehne), and blackberry (Rubus argutus Link) were moderate in viability (719%) after the third year of field storage, while seeds of beautyberry (Callicarpa americana L.), common greenbrier (Smilax rotundifolia L.), and summer grape (Vitis aestivalis Michx.) showed a high viability (3155%). Cumulative germination of seeds of deciduous holly (Ilex decidua Walt.) was greater after 3 years of field storage (8%) than after only 1 year (4%); for the first removal from field storage, no germination occurred until the ninth germination cycle. Results indicate that new seedlings of some species of shrubs and vines rely mostly on seeds dispersed shortly before or after disturbance, while seedlings of other species appear to develop from seeds that have been stored for long periods in the seed bank. Results of this study can be useful in developing ecologically sound strategies for controlling competing vegetation in forest stands of the southeastern United States.
AN ELEMENTARY APPROACH TO FORMAL WKB EXPANSIONS IN ℝn
Authors: KLEIN MARKUS , SCHWARZ ERIKA
Published: July 2002

In the classical limit, we construct the well-known formal WKB expansions for the eigenfunctions of a Schrödinger operator in the vicinity of a single nondegenerate C∞-potential well. Our elementary approach covers the case of eigenvalues degenerate in the harmonic approximation.
CYCLIC VECTORS IN THE ANDERSON MODEL
Authors: SIMON BARRY
Published: July 2002

We prove that for Anderson models in the localized regime, the vectors δn are cyclic with probability one and, in particular, the spectrum is simple.
ON SOME MOMENT MAPS AND INDUCED HOPF BUNDLES IN THE QUATERNIONIC PROJECTIVE SPACE
Authors: ORNEA LIVIU , PICCINNI PAOLO
Published: July 2002

We describe a diagram containing the zero sets of the moment maps associated to the diagonal U(1) and Sp(1) actions on the quaternionic projective space ℍPn. These sets are related both to focal sets of submanifolds and to Sasakian–Einstein structures on induced Hopf bundles. As an application, we construct a complex structure on the Stiefel manifolds [Formula: see text] and [Formula: see text], the one on the former manifold not being compatible with its known hypercomplex structure.
ON LOW-ENERGY EFFECTIVE ACTION OF NONCOMMUTATIVE HYPERMULTIPLET MODEL
Authors: SAMSONOV I. B.
Published: July 2002

We consider the noncommutative hypermultiplet model within harmonic superspace approach. The one-loop four-point contributions to the effective action of self-interacting q-hypermultiplet are computed. This model has two coupling constants instead of a single one in commutative case. It is shown that both coupling constants are generated by one-loop quantum corrections in the model of q-hypermultiplet interacting with vector multiplet. The holomorphic effective action of q-hypermultiplet in external gauge superfield is calculated. For the fundamental representation there is no uv/ir-mixing and the holomorphic potential is a ⋆-product generalization of a standard commutative one. For the adjoint representation of U(N) gauge group the leading contributions to the holomorphic effective action are given by the terms respecting for the uv/ir-mixing which are related to U(1) phase of U(N) group.
FUTURE SUMMARY
Authors: WILCZEK FRANK
Published: July 2002

We are emerging from a period of consolidation in particle physics. Its great, historic achievement was to establish the Theory of Matter. This Theory will serve as our description of ordinary matter under ordinary conditions — allowing for an extremely liberal definition of "ordinary" — for the foreseeable future. Yet there are many indications, ranging from the numerical to the semimystical, that a new fertile period lies before us. We will discover compelling evidence for the unification of fundamental forces and for new quantum dimensions (low-energy supersymmetry). We will identify new forms of matter, which dominate the mass density of the Universe. We will achieve much better fundamental understanding of the behavior of matter in extreme astrophysical and cosmological environments. Lying beyond these expectations, we can identify deep questions that seem to call for ideas outside our present grasp. And there is still plenty of room for surprises.
DOES ONE OBSERVE CHIRAL SYMMETRY RESTORATION IN BARYON SPECTRUM?
Authors: COHEN THOMAS D. , GLOZMAN LEONID YA.
Published: July 2002

It has recently been suggested that the parity doublet structure seen in the spectrum of highly excited baryons may be due to effective chiral symmetry restoration for these states. We review the recent developments in this field. We demonstrate with a simple quantum-mechanical example that it is a very natural property of quantum systems that a symmetry breaking effect which is important for the low-lying spectrum of the system, can become unimportant for the highly-lying states; the highly lying states reveal a multiplet structure of nearly degenerate states. Using the well-established concepts of quark–hadron duality, asymptotic freedom in QCD and validity of the operator product expansion in QCD, we show that the spectral densities obtained with the local currents that are connected to each other via chiral transformations, very high in the spectrum must coincide. Hence effects of spontaneous breaking of chiral symmetry in QCD vacuum that are crucially important for the low-lying spectra, become irrelevant for the highly-lying states. Then to the extent that identifiable hadronic resonances still exist in the continuum spectrum at high excitations, this implies that the highly excited hadrons must fall into multiplets associated with the representations of the chiral group. We demonstrate that this is indeed the case for meson spectra in the large Nc limit. All possible parity-chiral multiplets are classified for baryons and it is demonstrated that the existing data on highly excited N and Δ states at masses of 2 GeV and higher is consistent with approximate chiral symmetry restoration. However new experimental studies are needed to achieve any definitive conclusions.
p-ADIC AND ADELIC MINISUPERSPACE QUANTUM COSMOLOGY
Authors: DJORDJEVIĆ GORAN S. , DRAGOVICH BRANKO , NEŠIĆ LJUBIŠA D. , VOLOVICH IGOR V.
Published: July 2002

We consider the formulation and some elaboration of p-adic and adelic quantum cosmology. The adelic generalization of the Hartle–Hawking proposal does not work in models with matter fields. p-adic and adelic minisuperspace quantum cosmology is well defined as an ordinary application of p-adic and adelic quantum mechanics. It is illustrated by a few cosmological models in one, two and three minisuperspace dimensions. As a result of p-adic quantum effects and the adelic approach, these models exhibit some discreteness of the minisuperspace and cosmological constant. In particular, discreteness of the de Sitter space and its cosmological constant is emphasized.
QUANTUM HOLONOMIES FOR QUANTUM COMPUTING
Authors: PACHOS JIANNIS , ZANARDI PAOLO
Published: July 2002

Holonomic Quantum Computation (HQC) is an all-geometrical approach to quantum information processing. In the HQC strategy information is encoded in degenerate eigen-spaces of a parametric family of Hamiltonians. The computational network of unitary quantum gates is realized by driving adiabatically the Hamiltonian parameters along loops in a control manifold. By properly designing such loops the nontrivial curvature of the underlying bundle geometry gives rise to unitary transformations i.e., holonomies that implement the desired unitary transformations. Conditions necessary for universal QC are stated in terms of the curvature associated to the non-abelian gauge potential (connection) over the control manifold. In view of their geometrical nature the holonomic gates are robust against several kind of perturbations and imperfections. This fact along with the adiabatic fashion in which gates are performed makes in principle HQC an appealing way towards universal fault-tolerant QC.
A FOURTH ORDER DIFFUSION MONTE CARLO ALGORITHM FOR SOLVING QUANTUM MANY-BODY PROBLEMS
Authors: FORBERT H. A. , CHIN S. A.
Published: July 2002

We derive a fourth-order diffusion Monte Carlo algorithm for solving quantum many-body problems. The method uses a factorization of the imaginary time propagator in terms of the usual local energy E and Langevin operators L as well as an additional pseudo-potential consisting of the double commutator [EL, [L, EL]]. A new factorization of the propagator of the Fokker-Planck equation enables us to implement the Langevin algorithm to the necessary fourth order. We achieve this by the addition of correction terms to the drift steps and the use of a position-dependent Gaussian random walk. We show that in the case of bulk liquid helium the systematic step size errors are indeed fourth order over a wide range of step sizes.
A QUANTUM MONTE CARLO STUDY ON EXCITONIC COMPLEXES IN GaAs/AlGaAs QUANTUM WIRES
Authors: TSUCHIYA TAKUMA
Published: July 2002

Binding energies of biexcitons and charged excitons in GaAs/Al 0.3 Ga 0.7 As quantum wires were calculated by the diffusion Monte Carlo method. The binding energy for the negatively charged excitons is enhanced strongly, because of the mismatch of the electron and the hole wave functions. The resulting biexciton binding energy reproduces experimental results quite well.
A QUANTUM PERCEPTRON
Authors: ANDRECUT M. , ALI M. K.
Published: July 2002

The task of a classical perceptron is to classify two classes of patterns by generating a separation hyperplane. Here, we give a complete description of a quantum perceptron. The quantum algorithms for classification and learning are formulated in terms of unitary quantum gates operators. In the quantum case, the concept of separable or non-separable classes is irrelevant because the quantum perceptron can learn a superposition of patterns which are not separable by a hyperplane.
ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT
Authors: MA JIANPING , CHEN ZHIMING , LU GANG , YU MINGBIN , HANG LIANMAO , FENG XIANFENG , LEI TIANMIN
Published: July 2002

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.
HYPERBOLIC STRUCTURE ARISING FROM A KNOT INVARIANT II: COMPLETENESS
Authors: HIKAMI KAZUHIRO
Published: July 2002

We study the geometry of a knot invariant defined in terms of the quantum dilogarithm function. We show that a hyperbolic structure naturally arises in the classical limit of the invariant; the completeness conditions can also be identified with the saddle point equations by studying a (1,1)-tangle.