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Patent Classifications as Indicators of Intellectual Organization  [PDF]
Loet Leydesdorff
Physics , 2009,
Abstract: Using the 138,751 patents filed in 2006 under the Patent Cooperation Treaty, co-classification analysis is pursued on the basis of three- and four-digit codes in the International Patent Classification (IPC, 8th edition). The co-classifications among the patents enable us to analyze and visualize the relations among technologies at different levels of aggregation. The hypothesis that classifications might be considered as the organizers of patents into classes, and that therefore co-classification patterns--more than co-citation patterns--might be useful for mapping, is not corroborated. The classifications hang weakly together, even at the four-digit level at the country level, more specificity can be made visible. However, countries are not the appropriate units of analysis because patent portfolios are largely similar in many advanced countries in terms of the classes attributed. Instead of classes, one may wish to explore the mapping of title words as a better approach to visualize the intellectual organization of patents.
Evaluation of the Traditional and Revised WHO Classifications of Dengue Disease Severity  [PDF]
Federico Narvaez equal contributor,Gamaliel Gutierrez equal contributor,Maria Angeles Pérez,Douglas Elizondo,Andrea Nu?ez,Angel Balmaseda,Eva Harris
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001397
Abstract: Dengue is a major public health problem worldwide and continues to increase in incidence. Dengue virus (DENV) infection leads to a range of outcomes, including subclinical infection, undifferentiated febrile illness, Dengue Fever (DF), life-threatening syndromes with fluid loss and hypotensive shock, or other severe manifestations such as bleeding and organ failure. The long-standing World Health Organization (WHO) dengue classification and management scheme was recently revised, replacing DF, Dengue Hemorrhagic Fever (DHF), and Dengue Shock Syndrome (DSS) with Dengue without Warning Signs, Dengue with Warning Signs (abdominal pain, persistent vomiting, fluid accumulation, mucosal bleeding, lethargy, liver enlargement, increasing hematocrit with decreasing platelets) and Severe Dengue (SD; dengue with severe plasma leakage, severe bleeding, or organ failure). We evaluated the traditional and revised classification schemes against clinical intervention levels to determine how each captures disease severity using data from five years (2005–2010) of a hospital-based study of pediatric dengue in Managua, Nicaragua. Laboratory-confirmed dengue cases (n = 544) were categorized using both classification schemes and by level of care (I–III). Category I was out-patient care, Category II was in-patient care that did not meet criteria for Category III, which included ICU admission, ventilation, administration of inotropic drugs, or organ failure. Sensitivity and specificity to capture Category III care for DHF/DSS were 39.0% and 75.5%, respectively; sensitivity and specificity for SD were 92.1% and 78.5%, respectively. In this data set, DENV-2 was found to be significantly associated with DHF/DSS; however, this association was not observed with the revised classification. Among dengue-confirmed cases, the revised WHO classification for severe dengue appears to have higher sensitivity and specificity to identify cases in need of heightened care, although it is no longer as specific for a particular pathogenic entity as was the traditional schema.
Sensitivity and Specificity of the World Health Organization Dengue Classification Schemes for Severe Dengue Assessment in Children in Rio de Janeiro  [PDF]
Gleicy A. Macedo, Michelle Luiza C. Gonin, Sheila M. Pone, Oswaldo G. Cruz, Flávio F. Nobre, Patrícia Brasil
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0096314
Abstract: Background The clinical definition of severe dengue fever remains a challenge for researchers in hyperendemic areas like Brazil. The ability of the traditional (1997) as well as the revised (2009) World Health Organization (WHO) dengue case classification schemes to detect severe dengue cases was evaluated in 267 children admitted to hospital with laboratory-confirmed dengue. Principal Findings Using the traditional scheme, 28.5% of patients could not be assigned to any category, while the revised scheme categorized all patients. Intensive therapeutic interventions were used as the reference standard to evaluate the ability of both the traditional and revised schemes to detect severe dengue cases. Analyses of the classified cases (n = 183) demonstrated that the revised scheme had better sensitivity (86.8%, P<0.001), while the traditional scheme had better specificity (93.4%, P<0.001) for the detection of severe forms of dengue. Conclusions/Significance This improved sensitivity of the revised scheme allows for better case capture and increased ICU admission, which may aid pediatricians in avoiding deaths due to severe dengue among children, but, in turn, it may also result in the misclassification of the patients' condition as severe, reflected in the observed lower positive predictive value (61.6%, P<0.001) when compared with the traditional scheme (82.6%, P<0.001). The inclusion of unusual dengue manifestations in the revised scheme has not shifted the emphasis from the most important aspects of dengue disease and the major factors contributing to fatality in this study: shock with consequent organ dysfunction.
Decomposition of Independence Using the Logit Uniform Association Model and Equality of Concordance and Discordance for Two-Way Classifications  [PDF]
Kouji Tahata, Nobuko Miyamoto, Sadao Tomizawa
Open Journal of Statistics (OJS) , 2015, DOI: 10.4236/ojs.2015.56054

For two-way contingency tables with ordered categories, the present paper gives a theorem that the independence model holds if and only if the logit uniform association model holds and equality of concordance and discordance for all pairs of adjacent rows and all dichotomous collapsing of the columns holds. Using the theorem, we analyze the cross-classification of duodenal ulcer patients according to operation and dumping severity.

Medical Care Organization to Face Dengue Epidemics
Revista Cubana de Medicina Tropical , 2009,
Abstract: introduction: dengue is only a disease with a wide clinical spectrum including undifferentiated fever or fever with malaise and general manifestations, and severe dengue, induced mainly by plasma extravasation leading to prolonged or recurrent shock and death. medical care organization during epidemics is crucial to prevent fatalities and includes at least five components: 1. training of medical and nurse personnel. it is an investment that shall be programmed, controlled and evaluated. the time and resources for training must be considered as the equivalent of the expenses in still unavailable vaccines or drugs against dengue. 2. health education. to involve patients and their families in their own care, so that they can be prepared to ask for medical care at the right time, avoid self medication, identify skin bleedings (petechiae), and look for warning signs. 3. classification of every suspected dengue case (triage). a good classification of patients should be simple to be used in every place and should be dynamic to allow changes in treatment. early recognition of warning signs that announce dengue severity and intravenous fluids (crystalloids) given at that very moment can prevent dengue shock and other complications. 4. rearrangement of medical services and warranty of some resources. it is not correct to think that the preparation to face a dengue epidemic will include big amounts of drugs, blood and blood products. the most important resource continues being the human resource. if doctors and nurses are well trained, the prescription of such drugs and procedures will decrease, including platelet transfusion or blood transfusions. 5. research. biomedical and social research are needed, with emphasis on the impact of health education on patients and their families, the natural course of the illness and the best way to do ambulatory treatment. conclusions: the future of the severe dengue cases will be usually decided upon not in the intensive care unit but long
Utilities and Limitations of the World Health Organization 2009 Warning Signs for Adult Dengue Severity  [PDF]
Tun-Linn Thein equal contributor ,Victor C. Gan equal contributor,David C. Lye,Chee-Fu Yung,Yee-Sin Leo
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002023
Abstract: Background In 2009, the World Health Organization (WHO) proposed seven warning signs (WS) as criteria for hospitalization and predictors of severe dengue (SD). We assessed their performance for predicting dengue hemorrhagic fever (DHF) and SD in adult dengue. Method DHF, WS and SD were defined according to the WHO 1997 and 2009 dengue guidelines. We analyzed the prevalence, sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of WS before DHF and SD onset. Results Of 1507 cases, median age was 35 years (5th–95th percentile, 17–60), illness duration on admission 4 days (5th–95th percentile, 2–6) and length of hospitalization 5 days (5th–95th percentile, 3–7). DHF occurred in 298 (19.5%) and SD in 248 (16.5%). Of these, WS occurred before DHF in 124 and SD in 65 at median of two days before DHF or SD. Three commonest warning signs were lethargy, abdominal pain/tenderness and mucosal bleeding. No single WS alone or combined had Sn >64% in predicting severe disease. Specificity was >90% for both DHF and SD with persistent vomiting, hepatomegaly, hematocrit rise and rapid platelet drop, clinical fluid accumulation, and any 3 or 4 WS. Any one of seven WS had 96% Sn but only 18% Sp for SD. Conclusions No WS was highly sensitive in predicting subsequent DHF or SD in our confirmed adult dengue cohort. Persistent vomiting, hepatomegaly, hematocrit rise and rapid platelet drop, and clinical fluid accumulation, as well as any 3 or 4 WS were highly specific for DHF or SD.
La epidemiología del dengue y del dengue hemorrágico en Santiago de Cuba, 1997
Valdés,Luis; Guzmán,María G.; Kourí,Gustavo; Delgado,Jorge; Carbonell,Isabel; Cabrera,María V.; Rosario,Delfina; Vázquez,Susana;
Revista Panamericana de Salud Pública , 1999, DOI: 10.1590/S1020-49891999000600003
Abstract: a dengue epidemic that cuba reported in 1997 registered more than 500 000 cases of dengue fever produced by viral serotype 1. in 1981, there was an epidemic of dengue hemorrhagic fever produced by serotype 2 of the virus. this time 344 203 clinical cases were reported, 10 312 of which were severe cases of hemorragic fever that led to 158 fatalities (101 of them among children). the reintroduction of dengue, and specifically of dengue viral serotype 2 (jamaica genotype), was quickly detected in january 1997 through an active surveillance system with laboratory confirmation of cases in the municipality of santiago de cuba, in the province of the same name. the main epidemiological features of this outbreak are reported in this paper. a total of 3 012 cases were reported and serologically confirmed. these included 205 cases classified as dengue hemorrhagic fever/dengue shock syndrome (dhf/dss), 12 of which were case fatalities (all among adults). secondary infection with dengue virus was one of the most important risk factors for dhf/dss. ninety-eight percent of the dhf/dss cases and 92% of the fatal cases had contracted a secondary infection. it was the first time dengue hemorrhagic fever was documented as a secondary infection 16 to 20 years after initial infection. belonging to the white racial group was another important risk factor for dhf/dss, as had been observed during the 1981 epidemic. during the most recent epidemic it was demonstrated that the so called ?fever alert? is not useful for early detection of an epidemic. measures taken by the country?s public health officials prevented spread of the epidemic to other municipalities plagued by aedes aegypti.
La epidemiología del dengue y del dengue hemorrágico en Santiago de Cuba, 1997  [cached]
Valdés Luis,Guzmán María G.,Kourí Gustavo,Delgado Jorge
Revista Panamericana de Salud Pública , 1999,
Abstract: En 1977, Cuba informó de su primera epidemia de dengue, durante la cual se registraron más de 500 000 casos de fiebre del dengue causados por el serotipo 1 del virus. En 1981, se produjo una gran epidemia de dengue hemorrágico causada por el serotipo 2. Esa vez se notificaron 344 203 casos en total, 10 312 casos clínicos de dengue hemorrágico y 158 defunciones, de las cuales 101 correspondieron a ni os. Por medio de una búsqueda activa con confirmación de laboratorio, en el municipio de Santiago de Cuba de la provincia del mismo nombre se detectó precozmente en enero de 1997 la reintroducción del dengue, específicamente del virus del tipo 2, genotipo Jamaica. En este trabajo se presentan los aspectos epidemiológicos de mayor interés referentes a esa epidemia. Se notificaron 3 012 casos confirmados por serología, 205 clasificados como fiebre hemorrágica del dengue/síndrome de choque del dengue, de los cuales 12 fallecieron (todos adultos). La infección secundaria por virus del dengue fue uno de los principales factores de riesgo en el desarrollo de dengue hemorrágico y 98% de los casos, así como 92% de los fallecidos, manifestaron una respuesta de tipo secundario. Por primera vez se observó la posibilidad de contraer dengue hemorrágico en personas con una infección secundaria de 16 a 20 a os después de la primera infección. Pertenecer a la raza blanca fue otro factor de riesgo de importancia, tal como se había observado desde la epidemia de 1981. En la última epidemia se demostró que la llamada "alerta de fiebre" no es útil para la detección temprana de una epidemia. Las medidas tomadas por las autoridades sanitarias del país evitaron la extensión de la epidemia a otros municipios que estaban infestados por Aedes aegypti.
Predictive Tools for Severe Dengue Conforming to World Health Organization 2009 Criteria  [PDF]
Luis R. Carrasco,Yee Sin Leo ,Alex R. Cook,Vernon J. Lee,Tun L. Thein,Chi Jong Go,David C. Lye
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0002972
Abstract: Background Dengue causes 50 million infections per year, posing a large disease and economic burden in tropical and subtropical regions. Only a proportion of dengue cases require hospitalization, and predictive tools to triage dengue patients at greater risk of complications may optimize usage of limited healthcare resources. For severe dengue (SD), proposed by the World Health Organization (WHO) 2009 dengue guidelines, predictive tools are lacking. Methods We undertook a retrospective study of adult dengue patients in Tan Tock Seng Hospital, Singapore, from 2006 to 2008. Demographic, clinical and laboratory variables at presentation from dengue polymerase chain reaction-positive and serology-positive patients were used to predict the development of SD after hospitalization using generalized linear models (GLMs). Principal findings Predictive tools compatible with well-resourced and resource-limited settings – not requiring laboratory measurements – performed acceptably with optimism-corrected specificities of 29% and 27% respectively for 90% sensitivity. Higher risk of severe dengue (SD) was associated with female gender, lower than normal hematocrit level, abdominal distension, vomiting and fever on admission. Lower risk of SD was associated with more years of age (in a cohort with an interquartile range of 27–47 years of age), leucopenia and fever duration on admission. Among the warning signs proposed by WHO 2009, we found support for abdominal pain or tenderness and vomiting as predictors of combined forms of SD. Conclusions The application of these predictive tools in the clinical setting may reduce unnecessary admissions by 19% allowing the allocation of scarce public health resources to patients according to the severity of outcomes.
Clinical Relevance and Discriminatory Value of Elevated Liver Aminotransferase Levels for Dengue Severity  [PDF]
Linda K. Lee ,Victor C. Gan,Vernon J. Lee,Adriana S. Tan,Yee Sin Leo,David C. Lye
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001676
Abstract: Background Elevation of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) is prominent in acute dengue illness. The World Health Organization (WHO) 2009 dengue guidelines defined AST or ALT≥1000 units/liter (U/L) as a criterion for severe dengue. We aimed to assess the clinical relevance and discriminatory value of AST or ALT for dengue hemorrhagic fever (DHF) and severe dengue. Methodology/Principal Findings We retrospectively studied and classified polymerase chain reaction positive dengue patients from 2006 to 2008 treated at Tan Tock Seng Hospital, Singapore according to WHO 1997 and 2009 criteria for dengue severity. Of 690 dengue patients, 31% had DHF and 24% severe dengue. Elevated AST and ALT occurred in 86% and 46%, respectively. Seven had AST or ALT≥1000 U/L. None had acute liver failure but one patient died. Median AST and ALT values were significantly higher with increasing dengue severity by both WHO 1997 and 2009 criteria. However, they were poorly discriminatory between non-severe and severe dengue (e.g., AST area under the receiver operating characteristic [ROC] curve = 0.62; 95% confidence interval [CI]: 0.57–0.67) and between dengue fever (DF) and DHF (AST area under the ROC curve = 0.56; 95% CI: 0.52–0.61). There was significant overlap in AST and ALT values among patients with dengue with or without warning signs and severe dengue, and between those with DF and DHF. Conclusions Although aminotransferase levels increased in conjunction with dengue severity, AST or ALT values did not discriminate between DF and DHF or non-severe and severe dengue.
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