Efficient query expansion

Hundreds of millions of users each day search the web and other repositories to meet their information needs. However, queries can fail to find documents due to a mismatch in terminology. Query expansion seeks to address this problem by automatically adding terms from highly ranked documents to the query. While query expansion has been shown to be effective at improving query performance, the gain in effectiveness comes at a cost: expansion is slow and resource-intensive. Current techniques for query expansion use fixed values for key parameters, determined by tuning on test collections. We show that these parameters may not be generally applicable, and, more significantly, that the assumption that the same parameter settings can be used for all queries is invalid. Using detailed experiments, we demonstrate that new methods for choosing parameters must be found. In conventional approaches to query expansion, the additional terms are selected from highly ranked documents returned from an initial retrieval run. We demonstrate a new method of obtaining expansion terms, based on past user queries that are associated with documents in the collection. The most effective query expansion methods rely on costly retrieval and processing of feedback documents. We explore alternative methods for reducing query-evaluation costs, and propose a new method based on keeping a brief summary of each document in memory. This method allows query expansion to proceed three times faster than previously, while approximating the effectiveness of standard expansion. We investigate the use of document expansion, in which documents are augmented with related terms extracted from the corpus during indexing, as an alternative to query expansion. The overheads at query time are small. We propose and explore a range of corpus-based document expansion techniques and compare them to corpus-based query expansion on TREC data. These experiments show that document expansion delivers at best limited benefits, while query expansion, including standard techniques and efficient approaches described in recent work, usually delivers good gains. We conclude that document expansion is unpromising, but it is likely that the efficiency of query expansion can be further improved

Examining the pseudo-standard web search engine results page

Nearly every web search engine presents its results in an identical format: a ranked list of web page summaries. Each summary comprises a title; some sentence fragments usually containing words used in the query; and URL information about the page. In this study we present data from our pilot experiments with eye tracking equipment to examine how users interact with this standard list of results as presented by the Australian sensis.com.au web search service. In particular, we observe: different behaviours for navigational and informational queries; that users generally scan the list top to bottom; and that eyes rarely wander from the left of the page. We also attempt to correlate the number of bold words (query words) in a summary with the amount of time spent reading the summary. Unfortunately there is no substantial correlation, and so studies relying heavily on this assumption in the literature should be treated with caution

Role of ethylene on various ripening pathways and on the development of sensory quality of Charentais cantaloupe melons

Charentais melons (Cucumis melo L., var cantalupensis Naud.) in which ethylene biosynthesis has been suppressed by an antisense ACC oxidase gene have been used to better understand the role of ethylene in the regulation of the ripening process of climacteric fruit and on the development of sensory qualities. We have shown that a number of biochemical and molecular processes associated with the ripening of climacteric fruit are ethylene-independent. In some cases, such as softening of the flesh, the same pathway comprises both ethylene-dependent and -independent components. The various ethylene-dependent events exhibit differential sensitivity to ethylene. The threshold level for degreening of the rind is 1 ppm, while 2.5 ppm are required to trigger the ethylene-dependent component of the softening process. The saturating level of ethylene for all these events is less than 5 ppm, which is by far lower than the internal ethylene concentrations found in the fruit at the climacteric peak (around 100 ppm). Detachment of the fruit influences the development of respiratory climacteric. Fruit remaining attached to the vine, although producing higher levels of ethylene, exhibit a reduced climacteric rise in respiration as compared to detached fruit. The response of antisense ACO fruit to exogenous ethylene in terms of respiration is higher in detached than in attached fruit. Ethylene-suppressed melons show a severe reduction of aroma volatiles production, particularly in ester production. In the biosynthetic pathway of aliphatic esters, the dehydrogenation of fatty acids and aldehydes appears to be ethylene-dependent. In contrast, alcohol acetylation comprises ethylene-dependent and ethylene-independent components, probably corresponding to differentially regulated alcohol acetyl transferases. In terms of sensory quality, these data show that the extension of shelf-life through the inhibition of ethylene production has some beneficial effects on texture and sugar accumulation but is detrimental for the generation of aroma

Uso de marcação não radiativa para identificação de grandes rearranjos gênicos na deficiência da 21-hidroxilase

PURPOSE: To establish the Southern blotting technique using hybridization with a nonradioactive probe to detect large rearrangements of CYP21A2 in a Brazilian cohort with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH-21OH). METHOD: We studied 42 patients, 2 of them related, comprising 80 non-related alleles. DNA samples were obtained from peripheral blood, digested by restriction enzyme Taq I, submitted to Southern blotting and hybridized with biotin-labeled probes. RESULTS: This method was shown to be reliable with results similar to the radioactive-labeling method. We found CYP21A2 deletion (2.5%), large gene conversion (8.8%), CYP21AP deletion (3.8%), and CYP21A1P duplication (6.3%). These frequencies were similar to those found in our previous study in which a large number of cases were studied. Good hybridization patterns were achieved with a smaller amount of DNA (5 mug), and fragment signs were observed after 5 minutes to 1 hour of exposure. CONCLUSIONS: We established a non-radioactive (biotin) Southern blot/hybridization methodology for CYP21A2 large rearrangements with good results. Despite being more arduous, this technique is faster, requires a smaller amount of DNA, and most importantly, avoids problems with the use of radioactivity.OBJETIVO: Padronizar a técnica de Southern blotting usando hibridização com material não radioativo para detectar grandes rearranjos no gene CYP21A2 em uma amostra da população brasileira com hiperplasia adrenal congênita. MÉTODO: Foram estudados 42 pacientes, 2 dos quais aparentados, totalizando 80 alelos não relacionados. As amostras de DNA foram obtidas de sangue periférico, digeridas com enzima de restrição Taq I, realizado Southern blotting e hibridizadas com sonda marcada com biotina. RESULTADOS: O método se mostrou eficaz, com resultados similares aos encontrados ao utilizar a metodologia com material radioativo. Foram encontradas 2,5% de deleção do CYP21A2, 8,8% de grandes conversões, 3,8% de deleção do CYP21A1P e 6,3% de duplicação do CYP21A1P. Estas freqüências foram similares às encontradas em nosso estudo prévio, onde um número significante de casos foi estudado. Um bom padrão de hibridização foi alcançado utilizando menor quantidade de DNA (5mg) e a emissão de sinais foi observada entre 5 minutos e 1 hora de exposição. CONCLUSÕES: Padronizamos uma técnica de Southern blotting/ hibridização com material não radioativo (biotina) para a pesquisa de grandes rearranjos no gene CYP21A2 com bons resultados. Apesar de ser mais trabalhoso, este método é mais rápido, utiliza menores quantidades de DNA e, principalmente, evita problemas com o uso de radioatividade

Legitimacy in conflict: concepts, practices, challenges

The study of legitimacy in situations of conflict and peacebuilding has increased in recent years. However, current work on the topic adopts many assumptions, definitions, and understandings from classical legitimacy theory, which centers on the relationship between the nation-state and its citizens. In this introduction, we provide a detailed critical overview of current theories of legitimacy and legitimation and demonstrate why they have only limited applicability in conflict and post-conflict contexts, focusing on the three main areas that the articles included in this special issue examine: audiences for legitimacy, sources of legitimacy, and legitimation. In particular, we show how conflict and post-conflict contexts are marked by the fragmentation and personalization of power; the proliferation and fragmentation of legitimacy audiences; and ambiguity surrounding legitimation strategies

UN Peace operations and conflicting legitimacies

Analyses of UN peacekeeping increasingly consider legitimacy a key factor for success, conceiving of it as a resource that operations should seek and use in the pursuit of their goals. However, these analyses rarely break down legitimacy by source. Because the UN is an organization with multiple identities and duties however, different legitimacy sources—in particular output and procedural legitimacy—and the UN’s corresponding legitimation practices come into conflict in the context of peacekeeping. Drawing on a range of examples and a specific case of the UN mission in Congo, this article argues that looking at different legitimacy sources and linking them to the institutional identity of the UN is thus critical and it shows how the UN’s in contradictory legitimation practices can reduce overall legitimacy perceptions

Estatura alta e hipodesenvolvimento mamário após reposição estrogênica em paciente com hipogonadismo hipergonadotrófico e cariótipo 45,X/46,X, der(X) com superdosagem do gene SHOX

SHOX is exclusively expressed in the developing distal limb bones of human embryos and in the first and second pharyngeal arches. It works as a promoter for linear growth and as a repressor of growth plate fusion. It was reported, recently, that SHOX overdosage and gonadal estrogen deficiency have led to tall stature due to continued growth. We report, in the present study, a female patient with 45,X/46,X, psu idic(X)(pter→q21:q21→pter) karyotype, tall stature, and hypergonadotrophic hypogonadism without Turner stigmas. She did not present breast development even after long term therapy with high estrogen doses. Fluorescence in situ hybridization depicted the presence of three copies of SHOX gene. Microsatellite studies showed paternal origin of der(X). Further studies in similarly affected patients will clarify if the absence of breast development, despite previous high-dose estrogen treatment, is associated to triple copy of SHOX gene.O gene SHOX é expresso, exclusivamente, no primeiro e no segundo arcos faríngeos, assim como nas extremidades dos ossos dos membros em embriões humanos. SHOX normalmente atua como um promotor para o crescimento linear e como um repressor do fechamento da placa de crescimento. Recentemente, foi descrito que o excesso da proteína SHOX associada à deficiência estrogênica gonadal leva à estatura alta devido ao contínuo crescimento. Neste estudo descrevemos uma paciente do sexo feminino com cariótipo 45,X/46,X,psu idic(X)(pter→q21:q21→pter), estatura alta, hipogonadismo hipergonadotrófico e sem estigmas de Turner. A paciente não apresentou desenvolvimento de mamas, mesmo depois do tratamento prolongado com altas doses de estrógenos. FISH evidenciou a presença de três cópias do SHOX. Estudo de microssatélites demonstrou a origem paterna do der(X). Estudos futuros em pacientes com semelhanças clínicas esclarecerão se a ausência de desenvolvimento de mamas, apesar do tratamento com altas doses de estrógenos, está associada à tripla cópia do SHOX.Conselho Nacional de Pesquisa (CNPq

Insulin-like growth factor 1 gene (CA)n repeats and a variable number of tandem repeats of the insulin gene in Brazilian children born small for gestational age

OBJECTIVE: To investigate the influence of (CA)n repeats in the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene on birth size in children who are small or adequate-sized for gestational age and to correlate these polymorphisms with serum insulin-like growth factor 1 levels and insulin sensitivity in children who are small for gestational age, with and without catch-up growth. PATIENTS AND METHODS: We evaluated 439 infants: 297 that were adequate-sized for gestational age and 142 that were small for gestational age (66 with and 76 without catch-up). The number of (CA)n repeat in the insulin-like growth factor 1 gene and a variable number of tandem repeats in the insulin gene were analyzed using GENESCAN software and polymerase chain reaction followed by enzymatic digestion, respectively. Clinical and laboratory data were obtained from all patients. RESULTS: The height, body mass index, paternal height, target height and insulin-like growth factor 1 serum levels were higher in children who were small for gestational age with catch-up. There was no difference in the allelic and genotypic distributions of both polymorphisms between the adequate-sized and small infants or among small infants with and without catch-up. Similarly, the polymorphisms were not associated with clinical or laboratory variables. CONCLUSION: Polymorphisms of the (CA)n repeats of the insulin-like growth factor 1 gene and a variable number of tandem repeats of the insulin gene, separately or in combination, did not influence pre- or postnatal growth, insulin-like growth factor 1 serum levels or insulin resistance

"Here is your mission, now own it!" The rhetoric and practice of local ownership in EU interventions

One of the core principles of EU interventions under the Common Security and Defence Policy (CSDP) has been local ownership. While the EU takes pride in fully respecting this principle, the existing research suggests that the implementation has been far from smooth. However, we still know very little how this principle is conceptualised and operationalised, let alone why its implementation has been so difficult. Drawing on document analysis and 27 in-depth interviews, the article makes 3 arguments. First, ownership is increasingly construed in the EU policy rhetoric as a middle ground between imposition and restraint. Second, in practice, ownership is operationalised as an externally driven, top-down endeavour, resulting in the low degree of local participation. Third, in addition to the obstacles normally faced by other peace-builders, the EU's efforts to implement ownership are constrained by the politics and policy-making of CSDP. The arguments are illustrated in a case study of the European Union Mission on Regional Maritime Capacity Building in the Horn of Africa (EUCAP Nestor)