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Search Results: 1 - 10 of 191484 matches for " Marshall G.;Randi "
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Early colonization pattern of maize (Zea mays L. Poales, Poaceae) roots by Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae)
Monteiro, Rose A.;Schmidt, Maria A.;Baura, Valter A. de;Balsanelli, Eduardo;Wassem, Roseli;Yates, Marshall G.;Randi, Marco A.F.;Pedrosa, Fábio O.;Souza, Emanuel M. de;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008005000007
Abstract: the bacterium herbaspirillum seropedicae is an endophytic diazotroph found in several plants, including economically important poaceous species. however, the mechanisms involved in the interaction between h. seropedicae and these plants are not completely characterized. we investigated the attachment of herbaspirillum to maize roots and the invasion of the roots by this bacterium using h. seropedicae strain smr1 transformed with the suicide plasmid putkandsred, which carries a mini-tn5 transposon containing the gene for the discosoma red fluorescent protein (dsred) constitutively expressed together with the kanamycin resistance gene. integration of the mini-tn5 into the bacterial chromosome yielded the mutant h. seropedicae strain ram4 which was capable of expressing dsred and could be observed on and inside fresh maize root samples. confocal microscopy of maize roots inoculated with h. seropedicae three days after germination showed that h. seropedicae cell were attached to the root surface 30 min after inoculation, were visible in the internal tissues after twenty-four hours and in the endodermis, the central cylinder and xylem after three days.
Improved Tight Binding Parametrization for the Simulation of Stacking Faults in Aluminium
Anders G. Froseth,Peter M. Derlet,Randi Holmestad,Knut Marthinsen
Physics , 2003, DOI: 10.1103/PhysRevB.68.012105
Abstract: We refit the NRL tight binding parameterization for Aluminium by Mehl \emph{et al} [Phys. Rev. B, 61, 4894 (2000)], to a database generated via full potential Linearized Augmented Plane Wave (LAPW) Density Functional Theory (DFT) calculations. This is performed using a global optimization algorithm paying particular attention to reproducing the correct order of the angular symmetries of the tight binding fcc and bcc bandstructure. The resulting parameterization is found to better predict the hcp phase and both the stable and unstable planar stacking fault defect energies.
Algal composition and abundance in the neuston surface micro layer from a lake and pond in Virginia (U.S.A.)
Lubomira BURCHARDT,Harold G. MARSHALL
Journal of Limnology , 2003, DOI: 10.4081/jlimnol.2003.139
Abstract: A comparative study was conducted that characterized the algae within the neuston, ca 2 mm below the surface, and the algae in the water column from two freshwater habitats. There were significant differences in total algal abundance and the abundance of diatoms, cyanoprokaryotes, and chlorophytes between the neuston and water column algae of these two regions during each season and at both sites. The pond neuston was dominated by chlorophytes, with total algal abundance ranging seasonally from 0.6 to 59.6 × 10-3 cells ml-1 compared to water column algal concentrations of 4.1 to 40.4 × 10-3 cells ml-1. The lake was dystrophic, with diatoms the most common and abundant species, with the neuston algal abundance ranging from 0.09 to 1.31 × 10-3 cells ml-1, and the water column algae from 0.19 to 2.70 × 10-3 cells ml-1. Proximity to the variable nature of the surface layer was not a deterrent for neuston algal development, which frequently reached bloom status and contained a diverse assemblage of taxa.
Setting limits on supersymmetry using simplified models
C. Gütschow,Z. Marshall
Physics , 2012,
Abstract: Experimental limits on supersymmetry and similar theories are difficult to set because of the enormous available parameter space and difficult to generalize because of the complexity of single points. Therefore, more phenomenological, simplified models are becoming popular for setting experimental limits, as they have clearer physical implications. The use of these simplified model limits to set a real limit on a concrete theory has not, however, been demonstrated. This paper recasts simplified model limits into limits on a specific and complete supersymmetry model, minimal supergravity. Limits obtained under various physical assumptions are comparable to those produced by directed searches. A prescription is provided for calculating conservative and aggressive limits on additional theories. Using acceptance and efficiency tables along with the expected and observed numbers of events in various signal regions, LHC experimental results can be re-cast in this manner into almost any theoretical framework, including non-supersymmetric theories with supersymmetry-like signatures.
Forbidden Fruit Tastes the Sweetest—A Study of Norwegians’ Consumption Pattern of Chocolate, Sweets, Salty Snacks, Soft Drinks and the Like  [PDF]
Annechen Bahr Bugge, Randi Lavik
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.312212
Abstract: The theme of this study is eating and drinking patterns for products of which the health authorities want the Norwegian people to reduce their consumption. Although consumption development has shown positive trends over the past few years, Norwegians still have a much higher intake of such products than what is advisable. The study showed that only a small proportion had not eaten chocolate, sweets, sweet pastries, salty snacks etc. in the last seven days. Young people, men, people with low education and people living in households with children had the highest eating and drinking frequency of these kinds of products. Gender and age had the strongest impact on eating and drinking frequency. However, women had a higher eating rate of chocolate and sweets, and men had a higher eating and drinking frequency of salty snacks and sugary soda. People with low education had a considerably higher frequency of drinking sugary soda than people with high education. Among those who ate these products weekly, there were many who expressed that they would prefer to avoid such products, but that they were often tempted. Among those who ate these products a few times a month or less, few said that they did not like chocolate, sweets, etc. The main reason for having a relatively low eating and drinking frequency was that they perceived such products as unhealthy and fattening. Although there were only a few in the group of respondents who were concerned with healthy eating that had not eaten any of the listed products in the past seven days, this group had a significantly lower frequency of eating chocolate, sweets, etc. than the group that was not concerned with this. It was also clear that people who were health conscious to a greater extent limited eating of such products to the weekends and special occasions than those who were not. In order to succeed in reducing eating and drinking frequency of these products, it will be necessary to draw attention to product availability and social acceptance.
Common angiotensin receptor blockers may directly modulate the immune system via VDR, PPAR and CCR2b
Trevor G Marshall, Robert E Lee, Frances E Marshall
Theoretical Biology and Medical Modelling , 2006, DOI: 10.1186/1742-4682-3-1
Abstract: Telmisartan was predicted to strongly antagonize (Ki≈0.04nmol) the VDR. The ARBs Olmesartan, Irbesartan and Valsartan (Ki≈10 nmol) are likely to be useful VDR antagonists at typical in-vivo concentrations. Candesartan (Ki≈30 nmol) and Losartan (Ki≈70 nmol) may also usefully inhibit the VDR. Telmisartan is a strong modulator of PPARgamma (Ki≈0.3 nmol), while Losartan (Ki≈3 nmol), Irbesartan (Ki≈6 nmol), Olmesartan and Valsartan (Ki≈12 nmol) also seem likely to have significant PPAR modulatory activity. Olmesartan andIrbesartan (Ki≈9 nmol) additionally act as antagonists of a theoretical modelof CCR2b. Initial validation of this CCR2b model was performed, and a proposed model for the AngiotensinII Type1 receptor (AT2R1) has been presented.Molecular modeling has proven valuable to generate testable hypotheses concerning receptor/ligand binding and is an important tool in drug design. ARBs were designed to act as antagonists for AT2R1, and it was not surprising to discover their affinity for the structurally similar CCR2b. However, this study also found evidence that ARBs modulate the activation of two key nuclear receptors-VDR and PPARgamma. If our simulations are confirmed by experiment, it is possible that ARBs may become useful as potent anti-inflammatory agents, in addition to their current indication as cardiovascular drugs.Angiotensin Receptor Blockers (ARBs) act as antagonists of the AngiotensinII Type1 receptor (AT2R1) [Swiss-Prot:P30556], and were designed to treat moderate hypertension. Although ARBs have been marketed for nearly a decade, their mode of action is not fully understood, and debate still rages whether Angiotensin Converting Enzyme Inhibitors (ACEI) or ARBs are superior at reducing ultimate mortality due to cardiovascular dysfunction.An editorial in the New England Journal of Medicine concluded [1]:"in two recently reported clinical trials in which the investigators were allowed to increase the dose of Losartan gradually to 100 mg per day, there
Reviewing the reviewers: the vague accountability of research ethics committees
Randi Shaul
Critical Care , 2002, DOI: 10.1186/cc1469
Abstract: Although the need to review the ethics of research conducted in humans is generally accepted, there is less agreement over the extent to which reviewers are responsible or answerable for the decisions they make. What is the nature of reviewer accountability? RECs, like their US and Canadian counterparts (institutional review boards and research ethics boards, respectively), are responsible for assessing human research protocols for conformity to ethical principles. (For the purposes of this commentary, the term 'REC' will be used to refer to research ethics committees, institutional review boards and research ethics boards.) This role is currently strained by increases in the number of protocols that are in need of review, the scientific and funding complexities of the protocols [1,2], and a lack of clear standards for assessment of ethics [3]. To maintain or, in many cases, to restore public and professional trust in the ethics of human research, such as that done in critical care units, it is imperative that steps be taken to clarify the accountability of RECs and their individual members.Although human research has yielded phenomenal health and social benefits, the global scientific community has an unfortunate track record of harmful and exploitative research studies, in which the welfare of participants was sacrificed to competing interests of the investigators (for reviews of cases see Katz [4], Jones [5] and Weijer [6]). In recent years, even in some of the world's most prestigious research centres there have been many examples of noncompliance with ethical principles, resulting in preventable serious adverse events and inappropriate recruiting of subjects [7].Since World War II there have been several attempts, at both national and international levels [8,9,10,11,12,13], to articulate ethical principles for the conduct of research that involves humans. These codes and guidelines typically call upon RECs to approve, reject, or demand modifications to protocol
Museum theriological collections for the study of genetic diversity
Ettore Randi
Hystrix : the Italian Journal of Mammalogy , 2008, DOI: 10.4404/hystrix-18.2-4400
Abstract: Molecular methods to analyse DNA variability are opening new perspectives in the role played by museums in biodiversity research. DNA can be extracted from specific tissue collections, as well as from traditional voucher specimens. Ancient and museum DNA research produce valuable information for defining the phylogenetic positions of extinct taxa, the reconstruction of molecular and organismal evolution in extinct species, the characterization of extinct populations, including animal diets or microbial infections. Historical DNA samples are important sources of information also for conservation and evolutionary studies. In this paper, the methods used for ancient DNA analysis and the main results reported in published studies are reviewed. Riassunto Le collezioni teriologiche museali e lo studio della variabilità genetica. I metodi di analisi del DNA aprono nuove prospettive per il ruolo dei musei nello studio della biodiversità. Il DNA può essere estratto da collezioni di tessuti, oppure dai tradizionali materiali museali. Le ricerche che utilizzano DNA antico e museale possono produrre informazioni utili per definire la posizione filogenetica di taxa, la ricostruzione dell’evoluzione molecolare e fenotipica di specie e la caratterizzazione di popolazioni estinte, incluse l’identificazione della dieta e la presenza di malattie infettive. L’analisi del DNA estratto da campioni storici può fornire informazioni importanti anche per ricerche di biologia della conservazione. Si analizzano i metodi utilizzati per l’analisi del DNA antico, corredati da un breve excursus dei risultati delle principali ricerche disponibili in letteratura.
Filogeografia di alcune specie di mammiferi in Europa
Ettore Randi
Hystrix : the Italian Journal of Mammalogy , 2003, DOI: 10.4404/hystrix-14.0-4189
Abstract: La filogeografia si occupa dello studio della distribuzione geografica delle linee genetiche che sono presenti nelle popolazioni all'interno di una specie o in gruppi di specie filogeneticamente vicine. In Europa la distribuzione geografica della diversità genetica viene interpretata nel contesto dei cambiamenti climatici del Pleistocene, assumendo che i ripetuti cicli glaciali ed interglaciali abbiano determinato profonde trasformazioni nella distribuzione delle comunità e delle singole specie. Evidenze paleoecologiche e molecolari suggeriscono che le popolazioni di specie adattate ai climi temperati siano sopravissute alle glaciazioni in aree rifugio meridionali (sia nelle regioni Mediterranee che in Europa orientale), acquisendo caratteristiche genetiche peculiari. Nel corso dei periodi interglaciali, queste popolazioni hanno ricolonizzato l'Europa centrale e settentrionale, seguendo vie di dispersione che sono ricostruibili tramite l'analisi di specifici marcatori genetici. L'analisi filogeografica indica che ogni specie ha la propria storia. Tuttavia è possibile individuare alcuni "modelli" di filogeografia dei mammiferi in Europa: il modello classico dei rifugi meridionali (esemplificato dal caso del riccio, Erinaceus europaeus); un modello caratterizzato da successive fasi di colonizzazione da aree di speciazione in Eurasia (come nel caso del camoscio, Rupicapra), un modello caratterizzato dalla dislocazione settentrionale di intere popolazioni che scompaiono completamente dalle aree rifugio (come è avvenuto in alcune specie di chirotteri e di specie di ungulati a distribuzione settentrionale). Esistono, infine, casi di apparente mancanza di struttura filogeografica, come, ad esempio, nel caso del lupo e di altre specie ad elevato potenziale di dispersione e di flusso genico. L'analisi filogeografica consente di identificare alcune popolazioni di mammiferi distribuite nelle presunte aree di rifugio, comprendenti l'Italia centro-meridionale e la Sicilia, che hanno caratteristiche genetiche (e non solo genetiche) peculiari. L'analisi filogeografica contribuisce ad una miglior definizione della biodiversità e consente di ricostruire la storia delle popolazioni che si sono differenziate nel corso del Pleistocene.
Digitizing migration heritage: A case study of a minority museum
Randi Marselis
MedieKultur : Journal of Media and Communication Research , 2011,
Abstract: Museums are increasingly digitizing their collections and making them available to the public on-line. Creating such digital resources may become means for social inclusion. For museums that acknowledge migration history and cultures of ethnic minority groups as important subjects in multiethnic societies, digitization brings new possibilities for reaching source communities. This article describes Web projects conducted at Museum Maluku in Utrecht, the Netherlands. The article focuses on the museum’s experiences with cross-institutional Web projects, since digitization of the museum’s collection was initiated through collaboration with major national heritage institutions. The article also discusses how source communities through digital participation can become involved in building cultural heritage. Based on the case study of the Museum Maluku, it is argued that in order to design an appropriate mode of user participation as well as a sense of ownership it is crucial to take memory politics of source communities into account.
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