bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Reorganization in Chemical Reactions. Bond Order Conservation vs Multicenter Bonding in the Course of Chemical Reactions
Authors: Ponec Robert
Published: July 2002

The conditions underlying the applicability of the empirical BEBO relationship were analyzed and discussed. It has been shown that the relationship holds for reactions in which the electron reorganization can satisfactorily be described by the classical structural theory as a simple shift of bonds. On the other hand, if the electron reorganization is more complex, the BEBO relationship is likely to fail. In these cases, the description of the structure of the transition state requires to invoke the concept of multicenter bonding.
Adsorption and Condensation of Xanthine at the Mercury/Solution Interface
Authors: Dražan Viktor , Vetterl Vladimír
Published: July 2002

The adsorption and two-dimensional condensation of xanthine at the mercury electrode in 0.2 and 2 M NaCl was studied by electrode double layer capacity measurements. The condensation of xanthine molecules adsorbed at the electrode was observed at pH 6.0 and 7.4, but not at 9.0. The standard Gibbs energy of adsorption, energy of lateral interactions and the surface occupied by one xanthine molecule in a compact layer were calculated from the temperature dependence of the capacity pit using the Frumkin and Ising lattice gas models. The orientation of xanthine molecules in a compact layer at the electrode surface was estimated. At higher bulk concentrations of xanthine, the double layer capacity decreases to a very low value of about 1.5 mF cm-2, which might be an indication of the formation of a xanthine multilayer at the electrode surface.
Theoretical and Experimental Resolution of Semi-Derivative Linear Scan Voltammetry
Authors: Bobrowski Andrzej , Kasprzyk Grzegorz , Mocák Ján
Published: July 2002

New procedures, based on the transformation of voltammetric current by semi-differentiation, have been proposed to improve resolution in linear scan voltammetry (LSV). For a reversible charge transfer, the obtained shape of the current semi-derivative is fully symmetrical and even in the case of an irreversible electrode reaction it is considerably more symmetrical compared with the original LSV signal. To evaluate and compare the resolution of semi-derivative linear scan voltammetry (SDLSV) with other techniques, theoretical calculations were performed to determine the qualitative resolution as well as the quantitative resolution defined in our previous work. The following quantities have been calculated: (i) the minimal difference in the peak potentials of two depolarisers, necessary to obtain two distinct peaks on an SDLSV record, (ii) the difference in the peak potentials enabling the determination of the depolarisers with only a 1% systematic error, due to overlapping. Verification of the developed theory was performed experimentally using a set of solutions containing two electroactive components in 1 M HCl: Pb(II)-Tl(I), Pb(II)-In(III), Pb(II)-Cd(II), Tl(I)-In(III), Tl(I)-Cd(II), and In(III)-Cd(II). The proposed mathematical approach and experimental procedures enable a simultaneous SDLSV determination of two or even more depolarisers with a minimal error.
Impact of HIV-1 infection in South Africa
Authors: Pillay K , Colvin M , Williams R , Coovadia H M
Published: July 2002

In a prospective study, 60% of admissions to an academic hospital were infected with HIV. HIV infected children were younger, less likely to have been referred, more likely to have pneumonia and candidiasis, and had more health service attendances. This impact may be alleviated by appropriate primary and secondary level health care.
Behaviour and developmental effects of otitis media with effusion into the teens
Authors: Bennett K E , Haggard M P , Silva P A , Stewart I A
Published: July 2002

OBJECTIVE

To examine whether behavioural or cognitive sequelae of otitis media with effusion (OME) continue into late childhood and the early teens (11–18 years).

SETTING

Data from a large multipurpose birth cohort study: the Dunedin multidisciplinary health and development study.

PARTICIPANTS

Around 1000 children from the study. The main independent variable of interest was otological status of the child up to age 9.

MAIN OUTCOME MEASURES

Parent and teacher rated behaviour problems, including antisocial, neurotic, hyperactive, and inattentive behaviours, and tests of academic achievement including intelligence quotient (IQ), reading, and spelling were available in a high proportion of the cohort at ages 11 to 18 years.

RESULTS

After adjustments for covariates such as socioeconomic status, hyperactive and inattentive behaviour problems were evident as late as 15 years, and lower IQ associated with OME remained significant to 13 years. The largest effects were observed for deficits in reading ability between 11 and 18 years.

CONCLUSIONS

No previous study considering behaviour problems as an outcome has followed children long enough to determine whether some of the early sequelae of OME are still present in the early to late teens. Some developmental sequelae of OME, particularly deficits in reading ability, can persist into late childhood and the early teens.
Aerobic and anaerobic power responses to the practice of taekwon-do
Authors: Melhim A F
Published: July 2002

Background—Practising the martial art of taekwon-do (TKD) has been proposed to have beneficial effects on cardiovascular fitness as well as general physical ability. Furthermore, TKD masters and participants have promoted TKD as a total fitness programme. Research studies substantiating this, however, seem to be lacking, perhaps because TKD is recognised more as a method of self defence than a fitness programme.

Methods—Nineteen TKD practitioners with an average age of 13.8 years and 10.4 months of TKD training experience were recruited to participate. Measurements included resting heart rate, aerobic power, anaerobic power, and anaerobic capacity.

Results—Pairedttest analysis showed no significant differences in either resting heart rate or aerobic power after training. However, significant differences were observed in anaerobic power and anaerobic capacity (p = 0.05). The increases in anaerobic power and anaerobic capacity were 28% and 61.5% respectively.

Conclusion—The practice of TKD promotes anaerobic power and anaerobic capacity, but not aerobic power, in male adolescents.
Ultrasound diagnosis and neurodevelopmental outcome of localised and extensive cystic periventricular leucomalacia
Authors: Pierrat V , Duquennoy C , van Haastert I C , Ernst M , Guilley N , de Vries L S
Published: July 2002

AIMS

To compare the ultrasound (US) evolution and neurodevelopmental outcome of infants with localised (grade II) and extensive (grade III) cystic periventricular leucomalacia (c-PVL).

METHODS

Over a nine year period, c-PVL was diagnosed in 96/3451 (2.8%) infants in two hospital cohorts. Eighteen were excluded from the study. Thirty nine infants with grade II PVL were compared with 39 infants with grade III PVL.

RESULTS

The two populations were comparable for gestational age and birth weight. In infants with grade II PVL, cysts were noted to develop more often after the first month of life (53%) in contrast with grade III PVL (22%) (odds ratio (OR) 3.81 (95% confidence interval (CI) 1.19 to 12.63)). Cysts were also more often unilateral in grade II (54%) than in grade III PVL (0%) (OR indefinite; RR 3.17 (95% CI 2.16 to 4.64)). At 40 weeks postmenstrual age (PMA), cysts were no longer seen on US in 13/38 infants with grade II PVL, with ventriculomegaly being the only visible sequel in nine cases. In grade III PVL, cysts were still present in 25 of the 27 surviving infants. Nine infants with grade II PVL were free of motor sequelae at follow up compared with one infant with grade III PVL (OR 8.07 (95% CI 0.92 to 181.66)). Twenty two out of 29 children with grade II PVL who developed cerebral palsy achieved independent walking compared with 3/26 with grade III PVL (OR 75 (95% CI 11.4 to 662)).

CONCLUSIONS

In the cohort studied, 50% of the infants with c-PVL had a more localised form (grade II). In grade II PVL, the cysts developed beyond the first month of life in more than half of the cases and were often no longer visible, on US, at 40 weeks PMA. In order not to miss this diagnosis, sequential US should also be performed beyond the first month of life. Mild ventriculomegaly noted at term can sometimes be due to grade II c-PVL. Cerebral palsy was slightly less common and tended to be less severe in infants with grade II PVL than in those with grade III PVL.
Muscle changes in the neuroleptic malignant syndrome
Authors: Behan W M H , Madigan M , Clark B J , Goldberg J , McLellan D R
Published: July 2002

Aims—To characterise the skeletal muscle changes in the neuroleptic malignant syndrome (NMS).

Methods—Detailed light and ultrastructural examination was carried out on skeletal muscle from three cases of NMS, two associated with recreational drugs (3,4-methlenedioxymethylamphetamine (MDMA, Ecstasy) and lysergic acid diethylamide (LSD)) and one with antipsychotic drugs (fluoxetine (Prozac) and remoxipride hydrochloride monohydrate (Roxiam)).

Results—The muscles were grossly swollen and oedematous in all cases, in one with such severe local involvement that the diagnosis of sarcoma was considered. On microscopy, there was conspicuous oedema. In some fascicles less than 10% of fibres were affected whereas in others more than 50% were pale and enlarged. There was a spectrum of changes: tiny to large vacuoles replaced most of the sarcoplasm and were associated with necrosis. A striking feature in some fibres was the presence of contraction bands separating segments of oedematous myofibrils. Severe endomysial oedema was also detectable. There was a scanty mononuclear infiltrate but no evidence of regeneration.

Conclusions—The muscle changes associated with NMS are characteristic and may be helpful in differential diagnosis.
Pasteurella multocidameningitis in an adult: case report
Authors: Armstrong G R , Sen R A , Wilkinson J
Published: July 2002

Pasteurella multocidais known to form part of the normal flora in the nasopharynx or gastrointestinal tract in many domestic and wild animals. Most human Pmultocidainfections are soft tissue infections caused by dog or cat bites. Less commonly this bacterium is associated with infections affecting other organ systems of man. A case of fatal Pmultocidameningitis discovered at the necropsy of a 52 year old man is described. Pmultocidais an unusual causative agent of meningitis which tends to affect those at the extremes of age.
Postmortem findings after fatal anaphylactic reactions: Table 1
Authors: Pumphrey Richard S H , Roberts Ian S D
Published: July 2002

Aims—To determine the frequency at which classic manifestations of anaphylaxis are present at necropsy after fatal anaphylactic reactions.

Methods—A register has been established of fatal anaphylactic reactions in the UK since 1992, traced from the certified cause of death and other sources. Details of the previous medical history and the reaction suggest anaphylaxis as the cause of death for 130 cases; a postmortem report was available for 56.

Results—The 56 deaths studied included 19 reactions to bee or wasp venom, 16 to foods, and 21 to drugs or contrast media. Death occurred within one hour of anaphylaxis in 39 cases. Macroscopic findings included signs of asthma (mucous plugging and/or hyperinflated lungs) (15 of 56), petechial haemorrhages (10 of 56), pharyngeal/laryngeal oedema (23 of 56), but for 23 of 56 there was nothing indicative of an allergic death. Mast cell tryptase was raised in 14 of 16 cases tested; three of three tested had detectable IgE specific for the suspected allergen.

Conclusions—In many cases of fatal anaphylaxis no specific macroscopic findings are present at postmortem examination. This reflects the rapidity and mode of death, which is often the result of shock rather than asphyxia. Investigations that might help determine whether anaphylaxis was the cause of death had rarely been performed. In the presence of a typical clinical history, absence of postmortem findings does not exclude the diagnosis of anaphylaxis.
Western blotting is useful in the salivary diagnosis ofHelicobacter pyloriinfection
Authors: Ballam L D , Mendall M A , Asante M , Morris J , Strachan D P , Whincup P H , Cook D G
Published: July 2002

Background—The salivary diagnosis ofHelicobacter pyloriinfection offers attractive possibilities for the epidemiological study of infection in children. Salivary enzyme linked immunosorbent assay (ELISA) is less reliable then serum ELISA, owing to variable transudation of immunoglobulin. In addition, children are more difficult to study because of lower specific serum antibody concentrations toH pylori. The performance of salivary western blotting in comparison with serum western blotting and serum ELISA was investigated in school children.

Subjects and methods—Paired serum and saliva specimens were obtained from 665 school children aged 9–11 in 10 British towns. All saliva and serum specimens were first analysed by ELISA; subsequently, western blotting of both specimens was performed on 31 and 34 specimens, respectively, to establish the criteria for positivity for western blotting. The remaining 121 specimens were then tested blindly and saliva was compared with the serum.

Results—The sensitivity and specificity of salivary ELISA in the 665 specimens was 32 of 50 (64%) and 530 of 691 (87%), respectively, when compared with serum ELISA. The western blotting validation was performed on 28 subjects with positive serum and positive salivary ELISA, 28 saliva positives with negative serum, 16 saliva negatives with positive serum, and 50 doubly negative subjects. Compared with serum western blots, the sensitivity and specificity of salivary western blots was 38 of 47 (81%) and 68 of 75 (91%), respectively. Using serum ELISA as the gold standard, the sensitivity and specificity were 32 of 44 (73%) and 72 of 78 (92%), respectively, the specificity being significantly higher than salivary ELISA (p < 0.001).

Conclusion—Salivary western blotting for IgG is useful in the diagnosis ofH pyloriinfection and is superior to ELISA. It also permits the identification of pathogenic strains.
Recent advances in immunohistochemistry in the diagnosis of ovarian neoplasms
Authors: McCluggage W G
Published: July 2002

This leader reviews recent advances in immunohistochemistry that are useful in the diagnosis of ovarian neoplasms. These include the value of different anticytokeratin antibodies in the distinction between a primary ovarian adenocarcinoma and a metastatic adenocarcinoma, especially of colorectal origin. These antibodies have also helped to clarify the origin of the peritoneal disease in most cases of pseudomyxoma peritonei. The value of antibodies against so called tumour specific antigens, such as CA125 and HAM56, in determining the ovarian origin of an adenocarcinoma is also reviewed. In recent years, several studies have investigated the value of a variety of monoclonal antibodies in the diagnosis of ovarian sex cord stromal tumours and in the distinction between these neoplasms and their histological mimics. These antibodies include those directed against inhibin, CD99, Mullerian inhibiting substance, relaxin like factor, melan A, and calretinin. Of these, anti-α inhibin appears to be of most diagnostic value. It is stressed that these antibodies should always be used as part of a larger panel and not in isolation.J Clin Pathol(J Clin Pathol 2000;53:327–334)
One principle and three fallacies of disability studies
Authors: Harris John
Published: July 2002

My critics in this symposium illustrate one principle and three fallacies of disability studies. The principle, which we all share, is that all persons are equal and none are less equal than others. No disability, however slight, nor however severe, implies lesser moral, political or ethical status, worth or value. This is a version of the principle of equality. The three fallacies exhibited by some or all of my critics are the following: (1) Choosing to repair damage or dysfunction or to enhance function, implies either that the previous state is intolerable or that the person in that state is of lesser value or indicates that the individual in that state has a life that is not worthwhile or not thoroughly worth living. None of these implications hold. (2) Exercising choice in reproduction with the aim of producing children who will be either less damaged or diseased, or more healthy, or who will have enhanced capacities, violates the principle or equality. It does not. (3) Disability or impairment must be defined relative either to normalcy, “normal species functioning”, or “species typical functioning”. It is not necessarily so defined.
Developing standards for institutional ethics committees: lessons from the Netherlands
Authors: van der Kloot Meijburg H H , ter Meulen R H J
Published: July 2002

This article presents standards for setting up and educating institutional ethics committees (IECs). These standards are based on experiences in the Netherlands, where IECs have been established in a large number of health care institutions. Though the IEC has become a generally accepted institution within Dutch health care, there are concerns over its effectiveness regarding the improving of the moral quality of clinical decision making. Health care practitioners and members of IECs too, experience a gap between the IEC and the reality of the clinical environment. At this moment, there is interest in developing programmes which educate practitioners in moral issues and how to deal with them, using the method of a structured debate on the ward. The IEC will not be made obsolete by this development, but can play a guiding role in the implementation of such programmes. Current concerns are the lack of patient representation in the Dutch IEC, and the loss of contact with the local community of health care practitioners because of the merger of hospitals into bodies similar to UK National Health Service (NHS) trusts.
Factors affecting physicians' decisions to forgo life-sustaining treatments in terminal care
Authors: Hinkka H , Kosunen E , Metsänoja R , Lammi U-K , Kellokumpu-Lehtinen P
Published: July 2002

Objectives: Treatment decisions in ethically complex situations are known to depend on a physician's personal characteristics and medical experience. We sought to study variability in decisions to withdraw or withhold specific life-supporting treatments in terminal care and to evaluate the association between decisions and such background factors.

Design: Readiness to withdraw or withhold treatment options was studied using a terminal cancer patient scenario with alternatives. Physicians were asked about their attitudes, life values, experience, and training; sociodemographic data were also collected.

Setting: Finnish physicians, postal survey.

Survey sample: Five hundred general practitioners, 300 surgeons, 300 internists, and 82 oncologists.

Results: Treatments most often forgone were blood transfusion (82%) and thrombosis prophylaxis (81%). Least willingly abandoned were intravenous (IV) hydration (29%) and supplementary oxygen (13%). Female doctors were less likely to discontinue thrombosis prophylaxis (p=0.022) and supplementary oxygen (p<0.001), but more readilyxray (p=0.039) and laboratory (p=0.057) examinations. Young doctors were more likely to continue antibiotics (p=0.025), thrombosis prophylaxis (p=0.006), supplementary oxygen (p=0.004) and laboratory tests (p=0.041). Oncologists comprised the specialty most ready to forgo all studied treatments except antibiotics and blood transfusion. The family's wishes (alternative 1) significantly increased treatment activity. Young and female practitioners and oncologists were most influenced by family appeal. Advance directives (alternative 2) made decisions significantly more reserved and uniform. Different factors in the physician's background were found to predict decisions to withdraw antibiotics or IV hydration.

Conclusion: The considerable variation observed in doctors' decisions to forgo specific life-sustaining treatments (LST) was seen to depend on their personal background factors. Experience, supervision, and postgraduate education seemed to be associated with more reserved treatment decisions. To increase the objectivity of end of life decisions, training, and research are of prime significance in this ethically complex area of medicine.
Mortality from all cancers of asbestos factory workers in east London 1933–80
Authors: Berry G , Newhouse M L , Wagner J C
Published: July 2002

OBJECTIVE

To give the observed and expected deaths due to cancer at all separate sites in asbestos workers in east London, and to analyse these for overall effect and exposure-response trend.

METHODS

The mortality experience of a cohort of over 5000 men and women followed up for over 30 years since first exposure to asbestos has been extracted.

RESULTS

There was a large excess of deaths due to cancer (537 observed, 222 expected). Most of these were due to cancer of the lung (232 observed, 77 expected) and pleural (52) and peritoneal (48) mesothelioma. The exposure-response trend for all these three causes was highly significant. There was also an excess of cancer of the colon (27 observed, 15 expected) which was significantly related to exposure. There were significant excesses of cancer of the ovary, of the liver, and of the oesophagus but with no consistent relation to exposure.

CONCLUSIONS

The excess risk of cancer after exposure to asbestos was mainly due to cancer of the lung and mesothelioma. An exposure related excess of cancer of the colon was also detected but the possibility that some of these deaths may have been peritoneal mesotheliomas could not be excluded. There was no consistent evidence of exposure related excesses at any other site.
Exposure to crystalline silica, silicosis, and lung disease other than cancer in diatomaceous earth industry workers: a quantitative risk assessment
Authors: Park R , Rice F , Stayner L , Smith R , Gilbert S , Checkoway H
Published: July 2002

Objectives: To estimate excess lifetime risk of (a) mortality from lung disease other than cancer (LDOC), and, (b) onset of radiographic silicosis, arising from occupational exposure to respirable crystalline silica dust.

Methods: Data from a cohort of California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly as cristobalite) were reanalyzed with Poisson regression methods with internal and external adjustments for potential confounding by calendar time, age, smoking, Hispanic ethnicity, and time since first observation. Model fit was evaluated by comparing deviances and fitting cubic spline models. Lifetime risks of death from LDOC and radiographic silicosis were estimated up to age 85 with an actuarial approach accounting for competing causes of death.

Results: For deaths due to LDOC, a linear relative rate model gave the best fit in Poisson regression analyses. At the mean cumulative exposure of LDOC cases to silica, after adjustment for smoking, the estimated rate ratio was 4.2 (p<0.0001); at the maximum cumulative exposure of cases, the rate ratio was 18.4. The excess lifetime risk for white men exposed to respirable cristobalite dust for 45 years at the current permissible exposure limit (PEL; about 0.05 mg/m3) of the Occupational Safety and Health Administration was 54/1000 (95% confidence interval (95% CI) 17 to 150). For 70 incident cases of radiographic silicosis largely manifest before the end of employment, the best fit was also the linear relative rate model, predicting a rate ratio of 25.6 for silicosis at the mean cumulative exposure of the cases (p<0.0001). The excess lifetime risk for silicosis at the current PEL was 75/1000.

Conclusion: Current occupational health standards for crystalline silica permit risks of lung disease other than cancer far in excess of what is usually considered acceptable by the Occupational Safety and Health Administration (a lifetime risk of less than one in a thousand deaths).
Recurrence of adrenal aldosterone-producing adenoma
Authors: Calvo-Romero José María , Ramos-Salado Juan Lucio
Published: July 2002

Conn's syndrome (adrenal aldosterone-producing adenoma) and bilateral adrenal hyperplasia are the most common causes of primary aldosteronism. The treatment of choice for patients with aldosterone-producing adenoma is unilateral total adrenalectomy. Recurrence after adequate surgery is exceptional. We present a patient with recurrence of an aldosterone-producing adenoma in the right adrenal gland 9 years after adenomectomy of a aldosterone-producing adenoma in the same adrenal gland. We conclude that adenomectomy is not an adequate therapy for patients with adrenal aldosterone-producing adenoma.
Cervical tuberculous lymphadenopathy: changing clinical pattern and concepts in management
Authors: Jha B C , Dass A , Nagarkar N M , Gupta R , Singhal S
Published: July 2002

Tuberculosis is one of the biggest health challenges the world is facing. In this study the clinical pattern of patients with cervical lymphadenitis, who presented to the ear, nose, and throat outpatient department of the Government Medical College Hospital, Chandigarh, India between June 1997 and May 1998 is recorded. Tuberculosis accounted for 60 out of 94 cases of cervical lymph node enlargement. The commonest age group affected was 11–20 years. Constitutional symptoms were not present in most of the patients. Multiple matted nodes were seen in 23 patients but a single discrete node was seen in 18 patients. Upper deep jugular nodes were the most commonly affected lymph nodes. Discharging sinus and abscess formation were uncommon. Fine needle aspiration cytology yielded a positive diagnosis in 52 out of 56 patients. Chest lesions on radiography were evident in 16% of the patients. Mantoux test was positive and was more than 15 mm in most of the patients. This study shows that the classical picture of “scrofula” is no longer seen nowadays and can probably be explained by the earlier presentation of the disease.

All the patients were treated with short course daily chemotherapy for six months. Surgery was not required in the majority of patients except in four cases where excision biopsy was performed. Patients with abscess formation were managed with wide bore needle aspiration only. With a minimum six month period of follow up, no patient was found to have a recurrence of local or systemic disease.

This study emphasises the role of fine needle aspiration cytology in diagnosis and confirms the efficacy of six months short course chemotherapy.
The start of life: a history of obstetrics
Authors: Drife J
Published: July 2002

Obstetric intervention originally consisted of extraction of the baby, usually by the breech, to save the mother’s life in obstructed labour. Forceps, introduced in the 17th century, were later refined by men-midwives like William Smellie. In Victorian times, Simpson championed chloroform anaesthesia, Lister pioneered antisepsis, and caesarean section was introduced. In 1935, however, Britain’s maternal mortality rate was still around 400/100 000. It fell dramatically after antibiotics appeared and is now 11.4. In the 1960s ultrasound and electronic fetal monitoring became widely used. In 2000 the British caesarean section rate reached 20%. Worldwide, childbirth still causes 600 000 maternal deaths a year.
Allelic variation of aBeauveria bassiana(Ascomycota: Hypocreales) minisatellite is independent of host range and geographic origin
Authors: Coates Brad S , Hellmich Richard L , Lewis Leslie C
Published: July 2002

The minisatellite locus, BbMin1, was isolated from a partial Beauveria bassiana genomic library that consisted of poly(GA) flanked inserts. Polymerase chain reaction (PCR) of the BbMin1 repeat demonstrated allele size variation among 95 B. bassiana isolates. Amplification was also observed from single isolates of Beauveria amorpha, Beauveria brongniartii, and Beauveria caledonica. Eight alleles were identified at the haploid locus, where repeat number fluctuated between one and fourteen. AMOVA and θ (Fst) indicated that fixation of repeat number has not occurred within pathogenic ecotypes or geographically isolated samples of B. bassiana. Selective neutrality of allele size, the rate of BbMin1 mutation, and the age of the species may contribute to host and geographic independence of the marker. Presence of alleles with a large number of repeat units may be attributed to the rare occurrence of somatic recombination or DNA replication error. The molecular genetic marker was useful for the identification of genetic types of B. bassiana and related species.Key words: Beauveria bassiana, strain identification, minisatellite variation.
Assessing the level of collinearity betweenArabidopsis thalianaandBrassica napusforA. thalianachromosome 5
Authors: Parkin I AP , Lydiate D J , Trick M
Published: July 2002

This study describes a comprehensive comparison of chromosome 5 of the model crucifer Arabidopsis with the genome of its amphidiploid crop relative Brassica napus and introduces the use of in silico sequence homology to identify conserved loci between the two species. A region of chromosome 5, spanning 8 Mb, was found in six highly conserved copies in the B. napus genome. A single inversion appeared to be the predominant rearrangement that had separated the two lineages leading to the formation of Arabidopsis chromosome 5 and its homologues in B. napus. The observed results could be explained by the fusion of three ancestral genomes with strong similarities to modern-day Arabidopsis to generate the constituent diploid genomes of B. napus. This supports the hypothesis that the diploid Brassica genomes evolved from a common hexaploid ancestor. Alignment of the genetic linkage map of B. napus with the genomic sequence of Arabidopsis indicated that for specific regions a genetic distance of 1 cM in B. napus was equivalent to 285 Kb of Arabidopsis DNA sequence. This analysis strongly supports the application of Arabidopsis as a tool in marker development, map-based gene cloning, and candidate gene identification for the larger genomes of Brassica crop species.Key Words: comparative mapping, Brassica species, model crucifer, genome evolution, genome duplication.
2000 John C. Polanyi Award LectureMother Nature and the molecular Big Bang
Authors: Miller RJ Dwayne
Published: July 2002

Biological molecules are mesoscopic systems that bridge the quantum and classical worlds. At the single molecule level, there are often more than 1 × 104 degrees of freedom that are involved in protein-mediated processes. These molecules are sufficiently large that the bath coordinate convolved to the reaction at an active site is defined by the surrounding protein tertiary structure. In this context, the very interatomic forces that determine the active protein structures create a strongly associated system. Thus, the bath fluctuations leading to reactive crossings involve highly hindered motions within a myriad of local minima that would act to cast the reaction dynamics into the high viscosity limit appropriate to glasses. However, the time scales observed for biological events are orders of magnitude too fast to meet this anticipated categorization. In this context, the apparent deterministic nature of biological processes represents an enormous challenge to our understanding of chemical processes. Somehow Nature has discovered a molecular scaffolding that enables minute amounts of energy to be efficiently channeled to perform biological functions without becoming entrapped in local minima. Clearly, energy derived from chemical processes is highly directed in biological systems. To understand this problem, we must first understand how energy is redistributed among the different degrees of freedom and fully characterize the protein relaxation processes along representative reaction coordinates in relation to these dissipative processes. This paper discusses the development of new nonlinear spectroscopic methods that have enabled interferometric sensitivity to protein motions on femtosecond time scales appropriate to the very fastest motions (i.e., bond breaking or the molecular "Big Bang") out to the slowest relaxation steps. This work has led to the Collective Mode Coupling Model as an explanation of the required reduced dimensionality in biological systems. Within this model, the largest coupling coefficients of the reaction coordinate are to the damped inertial collective modes of the protein defined by the strongly correlated secondary structures. These modes act to guide the reaction along the correct seam(s) in an otherwise highly complex potential energy surface. The mechanism by which biological molecules have been able to harness chemical energy over meso-length scales represents the first step towards higher levels of organization. The new insight afforded by the collective mode mechanism may prove important in understanding this larger issue of scaling in biological systems.Key words: biodynamics, energy transduction, ultrafast spectroscopy, nonlinear spectroscopy, primary processes in biology.
PARTIAL *-ALGEBRAS OF CLOSABLE OPERATORS: A REVIEW
Authors: ANTOINE J.-P. , INOUE A. , TRAPANI C.
Published: July 2002

This paper reviews the theory of partial *-algebras of closable operators in Hilbert space (partial O*-algebras), with some emphasis on partial GW*-algebras. First we discuss the general properties and the various types of partial *-algebras and partial O*-algebras. Then we summarize the representation theory of partial *-algebras, including a generalized Gel’fand-Naimark-Segal construction; the main tool here is the notion of positive sesquilinear form, that we study in some detail (extendability, normality, order structure, …). Finally we turn to automorphisms and derivations of partial O*-algebras, and their mutual relationship. The central theme here is to find conditions that guarantee spatiality.
TOPOLOGICAL PARTIAL *-ALGEBRAS: BASIC PROPERTIES AND EXAMPLES
Authors: ANTOINE J.-P. , BAGARELLO F. , TRAPANI C.
Published: July 2002

Let [Formula: see text] be a partial *-algebra endowed with a topology τ that makes it into a locally convex topological vector space [Formula: see text]. Then [Formula: see text] is called a topological partial *-algebra if it satisfies a number of conditions, which all amount to require that the topology τ fits with the multiplier structure of [Formula: see text]. Besides the obvious cases of topological quasi *-algebras and CQ*-algebras, we examine several classes of potential topological partial *-algebras, either function spaces (lattices of Lp spaces on [0, 1] or on ℝ, amalgam spaces), or partial *-algebras of operators (operators on a partial inner product space, O*-algebras).
CORRUPTION AND THE OUTSIDER: MULTINATIONAL ENTERPRISES IN THE TRANSITIONAL ECONOMY OF VIETNAM
Authors: MAITLAND ELIZABETH
Published: July 2002

Transitional Vietnam exhibits key characteristics that economists argue are conducive to corrupt practices and, by knock-on effects, to slower economic growth. The process of liberalisation has shifted the status quo in Vietnam, permitting entry by a wider pool of bribe-takers and bribe-givers. Standard economic definitions of corruption focus on the abuse of public office for private gain, whereby corrupt practices are modelled as distortions in the distribution of government provided goods and services. This paper modifies existing models, specifying corruption as a distortion to the definition, allocation and/or enforcement of property rights. The model incorporates an explicit role for the incentive set that shapes behaviour by government officials, private individuals and firms. Abuse of public office is modelled as a distortion to property rights, including the re-assignment of private rights as the result of lobbying or rent-seeking activities. Local norms may sanction corruption against certain groups. The MNE is one case in point; others include different ethnic, religious and socio-economic groups. As outsiders in an environment historically hostile to "outsiders", MNEs represent "easy" corruption targets.
MAGNETIC INTERACTIONS IN Sm(Fe/Mn)6Sn6 INTERMETALLICS
Authors: HAN J. , YELON W. B. , JAMES W. J. , MARASINGHE G. K. , DUBENKO I. , ALI N.
Published: July 2002

The magnetic structure of the transition metal sublattice in induction-melted SmMn 6-x Fe x Sn 6 intermetallic alloys ( x = 0, 0.5, 1.0, 1.5, and 2.0) K have been studied by x-ray and neutron diffraction techniques and SQUID measurements. These intermetallics crystallize in the HoFe 6 Sn 6-type structure with the space group I mmm while the SmMn 6-x Fe x Sn 6 intermetallic alloys ( x = 0.5, 1.0, 1.5, and 2.0) have the TbFe 6 Sn 6-type structure with the space group C mcm. Lattice constant, a, b, c, and unit cell volume contract with increasing iron content The net magnetization exhibits a small magnitude variation within the iron content range investigated. The magnetic moment of the iron sublattice couples positively with ferromagnetically coupled manganese and samarium moments. The Curie temperature (Tc) first increases, goes through a maximum at about x = 1.5, and then decrease again with the increasing iron content. The easy direction of magnetization for all of the samples is parallel to the bc plane of the unit cell at 300 K.
SYMMETRY LOWERING IN THE PHOTOINDUCED PHASE IN SPIN-CROSSOVER COMPLEXES
Authors: TAYAGAKI TAKESHI , TANAKA KOICHIRO , YONEMURA NAOKI , SHIRAI MASANOBU , KAN'NO KEN-ICHI
Published: July 2002

We investigated the resonant Raman scattering of the spin-crossover complex, [ Fe(2-pic)3]Cl3EtOH , with varying the temperature and calarified for the first time that the photoinduced phase is completely different state from the thermally-induced phase. In the photoinduced phase we observed splits of Raman lines and a number of additional lines which are not observed in the high- and te low-temperature phase. These splits and appearances strongly indicate that a symmetry lowering should take place in the photoinduced phase. We imagined that the symmetry lowering is induced by the Jahn-Teller effect in the photo-excited state of the low-temperature phase.
THICKNESS AND OXYGEN PRESSURE DEPENDENT OPTICAL PROPERTIES OF NIOBIUM OXIDE THIN FILMS
Authors: KRISHNA M. GHANASHYAM , BHATTACHARYA A. K.
Published: July 2002

The optical properties of niobium oxide thin films in the thickness range between 75 and 200 nm have been studied. The films were deposited by dc magnetron sputtering and it was found that the refractive index, extinction coefficient and the absorption edge were all strongly dependent on the oxygen pressure during sputtering as well as the thickness of the deposited films. In general, the low thickness films had a lower refractive index than the high thickness films. The highest refractive index obtained was 2.46 at a wavelength of 650 nm for the film deposited at an oxygen pressure of 2 mTorr and to a thickness of 200 nm. The low thickness (~ 120 nm) films showed an initial decrease in refractive index, with oxygen pressure increasing above a critical value. The thicker films, however showed the opposite behaviour, increasing initially and decreasing marginally above the same critical pressure. The absorption edge showed a critical value of thickness above and below which it decreased and a critical value of oxygen pressure during sputtering above and below which it increased. The band gap values varied from 3.3 to 3.6 eV with the thinner films showing the higher band gap. The observed behaviour was explained using the single effective Lorentzian oscillator model.
PROPERTIES OF ZnO:AL THIN FILMS, OBTAINED BY THE SOL-GEL METHOD
Authors: ALTAMIRANO-JUAREZ D. C. , CASTANEDO-PEREZ R. , JIMENEZ-SANDOVAL O. , JIMENEZ-SANDOVAL S. , MARQUEZ-MARIN J. , TORRES-DELGADO G. , MALDONADO-ALVAREZ A.
Published: July 2002

Al-doped ZnO thin films have been prepared by the sol-gel technique, on slide-glass substrates. Al(NO3)3·9H2O was used as aluminum source and the doping range was 0.001-20 at %. The effect of the Al concentration in solution on the microstructure of the films is presented. The transmittance spectra, as well as the sheet resistance measurements, show the presence of electrically-active aluminum in the films.
BIFURCATIONS ANALYSIS OF POPULATION INVASION: ON–OFF INTERMITTENCY AND BASIN RIDDLING
Authors: DE FEO OSCAR , FERRIERE REGIS
Published: July 2002

We investigate the local bifurcations experienced by a time-discrete dynamical system from population biology when there is an attractor in an invariant subspace that loses stability. The system describes competition between two species in a constant environment; invariant subspaces contain single-species attractors; the loss of stability of the attractor in one invariant subspace means that the corresponding species (i.e. the "resident" species) becomes invadable by its competitor. The global dynamics may be understood by examining the sign structure of Lyapunov exponents transverse to the invariant subspace. When the transverse Lyapunov exponent (computed for the natural measure) changes from negative to positive on varying a parameter, the system experiences a so-called blowout bifurcation. We unfold two generic scenarios associated with blowout bifurcations: (1) a codimension-2 bifurcation involving heteroclinic chaos and on–off intermittency and (2) a sequence of riddling bifurcations that cause asymptotic indeterminacy. An ingredient that both scenarios have in common is the fact that the "resident" species subspace contains multiple invariant sets with transverse Lyapunov exponents that do not change sign simultaneously. This simple model adds on a short list of archetypical systems that are needed to investigate the structure of blowout bifurcations. From a biological viewpoint, the results imply that mutual invasibility in a constant environment is neither a necessary nor a sufficient condition for coexistence.
TWO-DIMENSIONAL BIFURCATION DIAGRAMS OF A CHAOTIC CIRCUIT BASED ON HYSTERESIS
Authors: BIZZARRI FEDERICO , STORACE MARCO
Published: July 2002

This paper deals with the bifurcation analysis of a chaotic oscillator based on hysteresis. The analysis is carried out using two different models of the nonlinear resistive elements of the oscillator. The first model (more convenient from an analysis point of view) is piecewise linear (PWL), whereas the second (more realistic from a synthesis point of view) is smooth. For both models, the main results presented in this paper are two-dimensional bifurcation diagrams obtained for several values of a third circuit parameter.
BIFURCATIONS AND CLUSTERING IN GLOBALLY COUPLED ARRAYS OF PHASE-BISTABLE SYSTEMS
Authors: McNEIL KEN
Published: July 2002

This paper considers the behavior of a system of globally coupled identical parametric oscillators. The coupling is linear, with a phase chosen so that the system takes on steady, rather than oscillatory, states, and this work focuses on bifurcations from the zero steady state. Approximate expressions are given for the states which emerge at these bifurcations, and full expressions are given for special cases. Secondary bifurcations are also briefly discussed.
BIFURCATION DYNAMICS IN CONTROL SYSTEMS
Authors: CHEN GUANRONG , LU JIALIANG , NICHOLAS BRENT , RANGANATHAN SWATIPRAKASH M.
Published: July 2002

This paper is to report the observation that when the popular time-delayed feedback strategy is used for control purpose, it may actually create unwanted bifurcations. Hopf bifurcation created by delayed feedback control is the main concern of this article, but some other types of bifurcations are also observed to exist in such delayed-feedback control systems. The observations are illustrated by computer simulations.
FEEDBACK LOOP IN EXTENDED VAN DER POL'S EQUATION APPLIED TO AN ECONOMIC MODEL OF CYCLES
Authors: BOUALI SAFIEDDINE
Published: July 2002

We connect to the Van der Pol's equation an appropriate feedback loop which unfolds a wide range of dynamic behavior. The bifurcation diagrams reveal the rise, then the extinction of the chaos bubble. Moreover, the numerical computations display an antisymmetric strange attractor with morphological plasticity by the variation of the sole feedback control parameter. This chaotic 3D system is built to found an heuristic model of economic cycles focused on the capital flight observed in the less developed countries. The model exhibits the ability of the potential GDP to drive the growth dynamic.
HAIRS FOR THE COMPLEX EXPONENTIAL FAMILY
Authors: BODELÓN CLARA , DEVANEY ROBERT L. , HAYES MICHAEL , ROBERTS GARETH , GOLDBERG LISA R. , HUBBARD JOHN H.
Published: July 2002

In this paper we consider both the dynamical and parameter planes for the complex exponential family Eλ(z)=λez where the parameter λ is complex. We show that there are infinitely many curves or "hairs" in the dynamical plane that contain points whose orbits under Eλ tend to infinity and hence are in the Julia set. We also show that there are similar hairs in the λ-plane. In this case, the hairs contain λ-values for which the orbit of 0 tends to infinity under the corresponding exponential. In this case it is known that the Julia set of Eλ is the entire complex plane.
BOUNDARY EFFECTS IN THE COMPLEX GINZBURGàLANDAU EQUATION
Authors: EGUÍLUZ VÍCTOR M. , HERNÁNDEZ-GARCÍA EMILIO , PIRO ORESTE
Published: July 2002

The effect of a finite geometry on the two-dimensional complex Ginzburg–Landau equation is addressed. Boundary effects induce the formation of novel states. For example, target-like solutions appear as robust solutions under Dirichlet boundary conditions. Synchronization of plane waves emitted by boundaries, entrainment by corner emission, and anchoring of defects by shock lines are also reported.
FROM C-CONTINUATIONS TO NEW QUADRATIC ALGORITHMS FOR AUTOMATON SYNTHESIS
Authors: CHAMPARNAUD J.-M. , ZIADI D.
Published: July 2002

Two classical non-deterministic automata recognize the language denoted by a regular expression: the position automaton which deduces from the position sets defined by Glushkov and McNaughton–Yamada, and the equation automaton which can be computed via Mirkin's prebases or Antimirov's partial derivatives. Let |E| be the size of the expression and ‖E‖ be its alphabetic width, i.e. the number of symbol occurrences. The number of states in the equation automaton is less than or equal to the number of states in the position automaton, which is equal to ‖E‖+1. On the other hand, the worst-case time complexity of Antimirov algorithm is O(‖E‖3· |E|2), while it is only O(‖E‖·|E|) for the most efficient implementations yielding the position automaton (Brüggemann–Klein, Chang and Paige, Champarnaud et al.). We present an O(|E|2) space and time algorithm to compute the equation automaton. It is based on the notion of canonical derivative which makes it possible to efficiently handle sets of word derivatives. By the way, canonical derivatives also lead to a new O(|E|2) space and time algorithm to construct the position automaton.
SOME EXACT SEQUENCES FOR THE HOMOTOPY (BI-)MODULE OF A MONOID
Authors: KOBAYASHI YUJI , OTTO FRIEDRICH
Published: July 2002

For finitely presented monoids the homological finiteness conditions left-[Formula: see text], left-[Formula: see text], right-[Formula: see text] and right-[Formula: see text], the homotopical finiteness conditions of having finite derivation type [Formula: see text] and of being of finite homological type [Formula: see text] are developed and the relationship between these notions is investigated in detail. In particular, a result of Pride [40] and Guba and Sapir [27] on the exactness of a sequence of bimodules for the homotopy module is proved in a completely different, purely combinatorial manner. This proof is then translated into a proof of the corresponding result for the left homotopy module, thus giving new insights into the relationship between the finiteness conditions considered.