124,678 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Risk factors and prevention of hepatocellular carcinoma in HCV infection
No full textAbstract
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Several risk factors for HCC development have been identified, including cirrhosis, hepatitis B virus (HBV) infection, and hepatitis C virus (HCV) infection. With regard to cirrhosis, multivariate analysis indicates that alcohol abuse, HBsAg positivity, and anti-HCV seropositivity are independent variables associated with an increased risk for HCC in the cirrhotic patient. A close relationship between chronic HBV infection and HCC has been established by epidemiological studies and laboratory investigations. Evidence indicates that HCV also plays a leading role in development of HCC. Most patients with HCV-related HCC develop the tumor as a consequence of long-standing infection accompanied by chronic and progressive liver damage. In our study of 290 consecutive patients with cirrhosis, patients with persistently elevated or fluctuating ALT levels had a significantly greater rate of HCC development. The mechanism of HCC development in HCV infection remains to be elucidated. The annual cumulative risk of developing HCC is approximately 1% in patients without cirrhosis at inclusion and 3-10% in those with cirrhosis, depending on the stage of cirrhosis and presence of etiological cofactors. Although some evidence suggests that patients infected with the HCV genotype 1b are at increased risk for development of more severe liver disease, including HCC, results of our prospective study do not support a difference between cirrhotic and noncirrhotic patients in terms of the natural course of cirrhosis and the rate of developing HCC based on genotype. Strategies to prevent HCV-related HCC include blood screening and treatment of chronic HCV infection with interferon-alpha. Recent studies suggest that interferon-alpha treatment may prevent the development of HCC in HCV infection. Further research is warranted
Patterns of hepatocellular carcinoma development in hepatitis B virus and hepatitis C virus related cirrhosis
No full textAbstract
To compare incidence, risk factors and morphologic pattern of hepatocellular carcinoma (HCC) development in hepatitis B virus (HBV) and hepatitis C virus (HCV) related cirrhosis, 401 patients were followed prospectively by periodic ultrasound examination for 14-189 months (mean: 84.8+/-36.7). During follow-up, 77 (19.2%) patients developed HCC, with 5 and 10 year cumulative incidence of 10 and 27.5%, respectively. The risk of HCC was significantly higher in HBV and HCV co-infected patients (P=0.014) compared to those with single HBsAg or anti-HCV (antibodies to hepatitis C virus) positivity. In anti-HCV positive cases the annual risk of HCC increased from 2% in the first 5 year period to 4% in the third 5 year period, while it decreased from 2 to 0% in the same time periods in the HBsAg positive group. By Cox's regression, age above 59 years (P=0.001), male sex (P=0.09), longer duration (P=0.04) and more advanced stage (P=0.01) of cirrhosis, lower platelets count (P=0.001) and higher ALT levels were significant risk factors for HCC in anti-HCV positive patients, while only high alpha-fetoprotein (AFP) levels during follow-up (P=0.04) was a significant risk factor for HCC in HBsAg positive cases. The pattern of HCC was nodular in 63 (81.8%) patients and infiltrating in 14 (18.2%), and the former type was associated with older age (P=0.0001), longer duration (P=0.002) and more advanced stage (P=0.0001) of cirrhosis but not with the viral etiology of disease. In contrast, development of infiltrating HCC was unrelated to age and disease duration and stage, and was associated with male sex (P=0.01), HBV infection (P=0.06) and HBV and HCV co-infection (P=0.0001). Our results indicate different incidence profile, risk factors and patterns of morphogenesis of HCC development in HBV and HCV associated cirrhosis, suggesting different mechanisms of carcinogenesis
Different patterns of hepatocellular carcinoma development in cirrhosis associated with hepatitis B virus and hepatitis C virus: a long-term prospective study
No full textThe use of click beetle pheromone traps to optimize the risk assessment of wireworm (Coleoptera: Elateridae) maize damage
No full textMaize seeds are routinely coated with insecticide to target Agriotes spp. larvae (wireworms). However, in order to find fields where pest control is actually needed, it might be useful to estimate the adult Agriotes population levels and thus the pressure they exert, with a low-cost risk assessment tool, such as YATLORf (Yf) sex pheromone traps. A database containing 17 consecutive years (1998–2014) of field monitoring was analyzed, with information including both pheromone-trap catches of adults and maize-plant damage by wireworms. Significant associations were discovered between seasonal adult catches in-field, subsequent wireworm populations, and plant damage/yield reduction. When each trap contained over 1,100 A. sordidus adults and over 210 A. brevis adults one year prior (Y-1), the risk of 15%-plus plant damage in Year 0 (Y0) increased by 6 times and 37 times respectively when compared with lower numbers. More than 1,000 A. brevis adults/trap two years prior (Y-2) increased the risk of 15%-plus plant damage in Y0 by 13 times when compared with lower numbers. Cumulative thresholds were also found in Y-1 and Y-2 at the same site. Yf threshold values allowed us to detect fields with a negligible crop-damage risk and thus to reduce the use of insecticides
Coinfection by hepatitis B virus and hepatitis C virus.
No full textAbstract
Coinfection by hepatotropic viruses can occur due to the fact that hepatitis B virus (HBV) and hepatitis C virus (HCV) share similar routes of transmission. Different clinical features of liver disease can be observed in infected patients, ranging from fulminant, acute and chronic hepatitis to hepatocellular carcinoma (HCC). The relative role of the infecting viruses in determining the final clinical picture is not yet well defined. Several reports indicate that clinical and pathological severity of liver disease among coinfected patients is increased and in patients with HCC, co-occurrence of both viruses is a common event. The potential mechanism of tumour development still remains speculative, although direct and indirect roles for both HBV and HCV have been proposed. At the molecular level, reciprocal interference of virus replication has been repeatedly described and the extent of interference is influenced by the infecting HCV genotype, genotype 1 of HCV having more efficient inhibitory activity on HBV than genotype 2. Sequence similarities between an arginine-rich nucleocapsid motif of both viruses could support these clinical observations. Concerning response rates to interferon therapy, no satisfactory results have been achieved to date, although identification of effective therapeutic schemes, based on virological status of both viruses are warranted
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Concurrent hepatitis B and C virus infection and risk of hepatocellular carcinoma in cirrhosis. A prospective study.
No full textAbstract
BACKGROUND:
Patients with cirrhosis have a high risk of hepatocellular carcinoma (HCC) but it is unclear how the etiology of liver disease influences tumor development. The authors evaluated hepatitis B and C virus (HBV, HCV) infection in cirrhosis in relation to the risk of HCC.
METHODS:
Two hundred and ninety consecutive cirrhotic patients were followed prospectively with periodic ultrasound examination. At entry, patients were tested for markers of HBV and HCV to assess relation to tumor development during follow-up.
RESULTS:
Twenty and five-tenths percent of patients were hepatitis B surface antigen (HBsAg) positive and 68.9% were positive for HCV antibodies. Previous alcohol abuse was present in 26.2%. During follow-up (46.3 +/- 21.4 months), HCC developed in 32 patients (11.0%) (annual incidence approximately 3%) including 19.6% of HBsAg-positive patients, 12.2% of HCV antibody positive patients and 14.4% of patients with a history of alcohol abuse. The highest rate of HCC was in patients with dual HBsAg and anti-HCV positivity with or without previous alcohol abuse, whereas the lowest incidence (0%) was in cases without risk factors. By univariate analysis, age older than 59 years (P < 0.005), longer duration of cirrhosis (P < 0.005), serum alpha-fetoprotein levels higher than 20 ng/ml (P < 0.05), and dual HBsAg and HCV positivity (P < 0.02) appeared to be associated with HCC. By multivariate analysis, age (P < 0.01), positivity for HBsAg and HCV antibodies (P < 0.05), male sex (P < 0.05), and previous alcohol abuse (P < 0.08) were independently related to tumor appearance.
CONCLUSIONS:
These results, although confirming that male sex and previous alcohol abuse are risk factors for hepatocellular carcinoma in cirrhosis, indicate that concurrent hepatitis B and C virus infection determines the highest risk of developing hepatocellular carcinoma
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