African Journals - An Evaluation of the Use of African-Published Journals in African Universities: Evaluating Impact

Teaching/Communication/Extension/Profession,

Causal Analysis of Some Biological Data for Illex illecebrosus from the Scotian Shelf

The method of path analysis is applied to data on the biology of the short-finned squid (Illex illecebrosus) from the Scotian Shelf. The variables considered in the analysis are catch, size, maturity, feeding, temperature and month. Four hypothesized causal models of the interrelationships of thesevariables are presented. Tamperature and month are shown to have a direct effect on catch-per-day as a measure of abundance, but they also have indirect effects through their action on the othervariables. The method of path analysis provides a framework forexplicitly examining hypotheses with respect to available data. More widespread application of the method to fisheries data seems warranted

Bushes of vibrational modes for Fermi-Pasta-Ulam chains

Some exact solutions and multi-mode invariant submanifolds were found for the Fermi-Pasta-Ulam (FPU) beta-model by Poggi and Ruffo in Phys. D 103 (1997) 251. In the present paper we demonstrate how results of such a type can be obtained for an arbitrary N-particle chain with periodic boundary conditions with the aid of our group-theoretical approach [Phys. D 117 (1998) 43] based on the concept of bushes of normal modes for mechanical systems with discrete symmetry. The integro-differential equation describing the FPU-alfa dynamics in the modal space is derived. The loss of stability of the bushes of modes for the FPU-alfa model, in particular, for the limiting case N >> 1 for the dynamical regime with displacement pattern having period twice the lattice spacing (Pi-mode) is studied. Our results for the FPU-alfa chain are compared with those by Poggi and Ruffo for the FPU-beta chain.Comment: To be published in Physica

On the Structure of the Fusion Ideal

We prove that there is a finite level-independent bound on the number of relations defining the fusion ring of positive energy representations of the loop group of a simple, simply connected Lie group. As an illustration, we compute the fusion ring of $G_2$ at all levels

Cosmology at the Millennium

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding Universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model, we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics -- inflation + cold dark matter -- holds the promise of extending our understanding to an even more fundamental level and much earlier times, as well as shedding light on the unification of the forces and particles of nature. As we enter the 21st century, a flood of observations is testing this paradigm.Comment: 44 pages LaTeX with 14 eps figures. To be published in the Centennial Volume of Reviews of Modern Physic

Expression of epithelial-mesenchymal transition-related genes in prostate tumours

Aim. To detect expression of EMT-related genes in prostate tumor samples and analyze a possible correlation between gene expression level and clinical characteristics of prostate cancer in different groups. Methods. Expression of 19 genes was analyzed in 37 frozen samples of prostate cancer tissues at different tumor stages and Gleason scores, 37 paired conventionally normal prostate tissues and 20 samples of prostate adenomas, using quantitative PCR. Results. We have found that nine genes were expressed differently in benign and malignant prostate tumors, namely AR (1 isof), AR (2 isof), PTEN, VIM, MMP9, KRT18, PCA3, HOTAIR and SCHLAP1. When different tumor stages were compared, we could identify six differentially expressed genes: KRT18, MMP9, VIM, PCA3, HOTAIR and SCHLAP1; when samples of tumors with different Gleason score were compared, we found that eight genes were expressed differently: AR (1isof), CDH1, KRT18, MMP9, OCLN, PCA3, HOTAIR and SCHLAP1. The data had a high level of heterogeneity pottentially due to various molecular subtypes of prostate cancer, i.e. a luminal subtype with ahigh expression of CDH1, OCLN, AR(1 isof), KRT18, NKX3-1 and PSA; the stem-like subtype with a high expression of mesenchymal markers CDH2, FN1 and VIM and low expression of the epithelial markers. It is noteworthy that lncRNAs were specifically expressed in these two molecular subtypes. Conclusions. EMT-related genes were differentially expressed in benign and malignant prostate tumors. High heterogeneity of expression levels, especially in adenocarcinoma groups, might suggest the existence of at least two different molecular subtypes, luminal and stem-like. Further experiments are necessary for specification of the molecular subtypes of prostate adenocarcinoma.Мета. Встановити відносну експресію у ЕМП-пов’язаних генах у зразках пухлин передміхурової залози та проаналізувати можливу кореляцію та зв'язок між рівнем експресії генів у різних групах пухлин та клінічними характеристиками раку передміхурової залози. Методи. Відносні рівні експресії 19 генів у 37 заморожених зразках тканин раку передміхурової залози з різними показниками Глісона та стадіями пухлин, 37 парних умовно-нормальних зразків тканини передміхурової залози та 20 зразків аденоми простати було детектовано кількісною ПЛР (QPCR). Результати. Було виявлено 9 диференційно експресованих генів у доброякісних та злоякісних пухлинах простати: (AR (1 isof), AR (2 isof), PTEN, VIM, MMP9, KRT18, PCA3, HOTAIR, SCHLAP1). На різних стадіях раку виявлено 6 диференційно експресованих генів (KRT18, MMP9, VIM, PCA3, HOTAIR, SCHLAP1), а за різними оцінками Глісона виявлено 8 диференційно експресованих генів (AR (1 isof), CDH1, KRT18, MMP9, OCLN, PCA3, HOTAIR, SCHLAP1). Спостерігався значний рівень дисперсії даних. Це можна пояснити наявністю різних молекулярних підтипів раку передміхурової залози: люмінальний підтип (висока експресія CDH1, OCLN, AR (1 isof), KRT18, NKX3-1, PSA) і стовбуровий (базальний) підтип (висока експресія мезенхимальних маркерів CDH2, FN1, VIM і низька експресія епітеліальних маркерів). Досліджені некодуючі РНК були специфічно експресованіі у двох молекулярних підтипах. Висновки. пов'язані з ЕМП гени диференційно експресуються у доброякісних та злоякісних пухлинах передміхурової залози. Висока дисперсія даних експресії, особливо в групах аденокарциноми, може бути свідченням принаймні двох різних молекулярних підтипів: люмінального і стовбурового (базального). Нами продемонструвано, що умовно-нормальні тканини передміхурової залози не є адекватним контролем. Для уточнення молекулярних підтипів аденокарциноми передміхурової залози необхідні додаткові дослідження.Цель. Установить уровни относительной экспрессии генов, связанных с ЭМП, в образцах опухолей предстательной железы и проанализировать возможную корреляцию и взаимосвязь между уровнем экспрессии генов в разных группах опухолей и клиническими характеристиками рака простаты. Методы. Относительные уровни экспрессии 19 генов в 37 замороженных образцах тканей рака предстательной железы с разными показателями Глисона и стадиями рака, 37 парных образцов условно-нормальной ткани простаты и 20 образцов аденомы предстательной железы были проанализированы с помощью количественной ПЦР (QPCR). Результаты. Было выявлено 9 дифференциально экспрессированных генов в доброкачественных и злокачественных опухолях предстательной железы: (AR (1 isof), AR (2 isof), PTEN, VIM, MMP9, KRT18, PCA3, HOTAIR, SCHLAP1). На разных стадиях рака были идентифицированы 6 дифференциально экспрессированных генов (KRT18, MMP9, VIM, PCA3, HOTAIR, SCHLAP1), тогда как с разными показателями по шкале Глисона было найдено 8 дифференциально экспрессированных генов (AR (1isof), CDH1, KRT18, MMP9, OCLN, PCA3, HOTAIR, SCHLAP1). Наблюдалась очень высокая дисперсия данных. Это может быть объяснено наличием различных молекулярных подтипов рака предстательной железы: люминального подтипа (высокая экспрессия CDH1, OCLN, AR (1 изоф), KRT18, NKX3-1, PSA) и стволового (базального) подтипа (высокая экспрессия мезенхимальных маркеров CDH2, FN1, VIM и низкая экспрессия эпителиальных маркеров). Исследованные некодирующие РНК специфически экспрессировались в двух молекулярных подтипах. Выводы. Гены, связанные с ЭМП, были дифференциально экспрессированы в доброкачественных и злокачественных опухолях предстательной железы. Высокая дисперсия данных экспрессии, особенно в группе аденокарцином, может свидетельствовать, по меньшей мере, о двух разных молекулярных подтипах: люминальном и базальном. Мы продемонстрировали, что условно-нормальные ткани простаты не являются адекватным контролем. Для уточнения молекулярных подтипов аденокарциномы предстательной железы необходимы дополнительные исследования

Supplementary data for: Missed Diagnoses and Health Problems in Adults With Prader-Willi Syndrome: Recommendations for Screening and Treatment

Context: Prader-Willi syndrome (PWS) is a complex hypothalamic disorder, combining hyperphagia, hypotonia, intellectual disability, and pituitary hormone deficiencies. Annual mortality of patients with PWS is high (3%). In half of the patients, the cause of death is obesity related and/or of cardiopulmonary origin. Health problems leading to this increased mortality often remain undetected due to the complexity and rareness of the syndrome. Objective: To assess the prevalence of health problems in adults with PWS retrospectively. Patients, Design, and Setting: We systematically screened 115 PWS adults for undiagnosed health problems. All patients visited the multidisciplinary outpatient clinic for rare endocrine syndromes at the Erasmus University Medical Center, Rotterdam, Netherlands. We collected the results of medical questionnaires, interviews, physical xaminations, biochemical measurements, polygraphy, polysomnography, and radiology. Main outcome measures: Presence or absence of endocrine and nonendocrine comorbidities in relation to living situation, body mass index, genotype, and demographic factors. Results: Seventy patients (61%) had undiagnosed health problems, while 1 in every 4 patients had multiple undiagnosed health problems simultaneously. All males and 93% of females had hypogonadism, 74% had scoliosis, 18% had hypertension, 19% had hypercholesterolemia, 17% had type 2 diabetes mellitus, and 17% had hypothyroidism. Unfavorable lifestyles were common: 22% exercised too little (according to PWS criteria) and 37% did not see a dietitian. Conclusions: Systematic screening revealed many undiagnosed health problems in PWS adults. Based on patient characteristics, we provide an algorithm for diagnostics and treatment, with the aim to prevent early complications and reduce mortality in this vulnerable patient group

Identified particles in Au+Au collisions at sqrt{s_NN} = 200 GeV

The yields of identified particles have been measured at RHIC for Au+Au collisions at sqrt{s_NN} = 200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.Comment: 4 pages, 4 figures, Contribution to Quark Matter 2002, Nantes, France, July 200