153 research outputs found

    The King Ranch

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    In the southernmost tip of Texas the point that juts down into Mexico along the Gulf-lies the King ranch, the largest cattle ranch of its kind in the world. The heirs of Captain Richard King now rule over a domain of 1,250,000 acres-an estate worth $22,000,000. It is so big that there is a full month\u27s difference in seasons between the southernmost boundary and the northernmost tip. It is so large that the cars carry compasses to navigate from pasture to pasture and always go out in pairs lest they have a breakdown fifty miles from nowhere. So vast is the ranch that cars run out of gasoline between settlements and must replenish their tanks enroute from the numerous ranch-owned filling stations located at strategic points on the King domain

    Redefining Case Study

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    Abstract: In this paper the authors propose a more precise and encompass-ing definition of case study than is usually found. They support their defini-tion by clarifying that case study is neither a method nor a methodology nor a research design as suggested by others. They use a case study prototype of their own design to propose common properties of case study and demon-strate how these properties support their definition. Next, they present sev-eral living myths about case study and refute them in relation to their definition. Finally, they discuss the interplay between the terms case study and unit of analysis to further delineate their definition of case study. The target audiences for this paper include case study researchers, research de-sign and methods instructors, and graduate students interested in case study research

    Detection of K-Ras mutations in tumour samples of patients with non-small cell lung cancer using PNA-mediated PCR clamping

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    Non-small cell lung cancers (NSCLC), in particular adenocarcinoma, are often mixed with normal cells. Therefore, low sensitivity of direct sequencing used for K-Ras mutation analysis could be inadequate in some cases. Our study focused on the possibility to increase the detection of K-Ras mutations in cases of low tumour cellularity. Besides direct sequencing, we used wild-type hybridisation probes and peptide-nucleic-acid (PNA)-mediated PCR clamping to detect mutations at codons 12 and 13, in 114 routine consecutive NSCLC frozen surgical tumours untreated by targeted drugs. The sensitivity of the analysis without or with PNA was 10 and 1% of tumour DNA, respectively. Direct sequencing revealed K-Ras mutations in 11 out of 114 tumours (10%). Using PNA-mediated PCR clamping, 10 additional cases of K-Ras mutations were detected (21 out of 114, 18%, P<0.005), among which five in samples with low tumour cellularity. In adenocarcinoma, K-Ras mutation frequency increased from 7 out of 55 (13%) by direct sequencing to 15 out of 55 (27%) by clamped-PCR (P<0.005). K-Ras mutations detected by these sensitive techniques lost its prognostic value. In conclusion, a rapid and sensitive PCR-clamping test avoiding macro or micro dissection could be proposed in routine analysis especially for NSCLC samples with low percentage of tumour cells such as bronchial biopsies or after neoadjuvant chemotherapy

    Nucleic acid-based fluorescent probes and their analytical potential

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    It is well known that nucleic acids play an essential role in living organisms because they store and transmit genetic information and use that information to direct the synthesis of proteins. However, less is known about the ability of nucleic acids to bind specific ligands and the application of oligonucleotides as molecular probes or biosensors. Oligonucleotide probes are single-stranded nucleic acid fragments that can be tailored to have high specificity and affinity for different targets including nucleic acids, proteins, small molecules, and ions. One can divide oligonucleotide-based probes into two main categories: hybridization probes that are based on the formation of complementary base-pairs, and aptamer probes that exploit selective recognition of nonnucleic acid analytes and may be compared with immunosensors. Design and construction of hybridization and aptamer probes are similar. Typically, oligonucleotide (DNA, RNA) with predefined base sequence and length is modified by covalent attachment of reporter groups (one or more fluorophores in fluorescence-based probes). The fluorescent labels act as transducers that transform biorecognition (hybridization, ligand binding) into a fluorescence signal. Fluorescent labels have several advantages, for example high sensitivity and multiple transduction approaches (fluorescence quenching or enhancement, fluorescence anisotropy, fluorescence lifetime, fluorescence resonance energy transfer (FRET), and excimer-monomer light switching). These multiple signaling options combined with the design flexibility of the recognition element (DNA, RNA, PNA, LNA) and various labeling strategies contribute to development of numerous selective and sensitive bioassays. This review covers fundamentals of the design and engineering of oligonucleotide probes, describes typical construction approaches, and discusses examples of probes used both in hybridization studies and in aptamer-based assays

    An expanding culture of control? The municipal administrative sanctions Act in Belgium

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    This article provides an in-depth study of the Act on Municipal Administrative Sanctions 1999 (MAS), which is the first major piece of legislation regulating antisocial behaviour in Belgium. MAS provides municipalities with an instrument to sanction antisocial behaviour and conduct perceived to disturb public order. The article uses Garland’s(2001) thesisonthecultureofcontroltoanalysewhetherMAShasledtoincreasedgovernmentcontrol and the exclusion of significant groups of the population. The research is based on a multiple case study in which the application of MAS was analysed over a 25-year period of security policies in Belgium (1985–2010). The Act’s implementation was studied in the two Belgian cities of Antwerp and Liège in order to consider the influence of the Flemish government and the Walloon government, respectively, in this policy area. The article uses insights from this comparison to revisit the culture of control thesis and its limitations in understanding the political competition that exists over the formulation of policies on antisocial behaviour. Effective Protection of Fundamental Rights in a pluralist worl
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