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Sample records for anti-tuberculosis treatment defaulting

  1. Anti-tuberculosis treatment defaulting: an analysis of perceptions and interactions in Chiapas, Mexico Abandono del tratamiento antituberculosis: un análisis de percepciones e interacciones en Chiapas, México

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    Ivett Reyes-Guillén

    2008-06-01

    Full Text Available OBJECTIVE: To analyze the perceptions and interactions of the actors involved in anti-tuberculosis treatment, and to explore their influence in treatment defaulting in Los Altos region of Chiapas, Mexico. MATERIAL AND METHODS: From November 2002 to August 2003, in-depth interviews were administered to patients with PTB, patients' family members, institutional physicians, community health coordinators, and traditional medicine practitioners. RESULTS: We found different perceptions about PTB between patients and their families and among health personnel, as well as communication barriers between actors. Defaulting is considered to be mainly due to the treatment's adverse effects. CONCLUSIONS: It is necessary to conduct research and interventions in the studied area with the aim of changing perceptions, improving sensitization, quality and suitability of management of patients with PTB in a multicultural context, and promoting collaboration between institutional and traditional medicine.OBJETIVO: Analizar percepciones e interacciones entre actores involucrados en el tratamiento antituberculosis y su influencia en el abandono del tratamiento en los Altos de Chiapas, México. MATERIAL Y MÉTODOS: De noviembre 2002 a agosto 2003, se realizaron entrevistas a profundidad a pacientes con TBP, familiares, médicos institucionales, coordinadores comunitarios de salud y médicos tradicionales. RESULTADOS: Se encontraron diferentes percepciones entre los pacientes y sus familiares, respecto a las del personal de salud, así como barreras de comunicación entre los distintos actores. Los efectos adversos del tratamiento antituberculosis, son consideradas como una de las principales causas de su abandono. CONCLUSIONES: Es necesario que en la región estudiada se realicen investigaciones e intervenciones encaminadas a: cambiar percepciones y mejorar la sensibilidad, calidad y adecuación del manejo de pacientes con TBP en contextos multiculturales, así como

  2. Early stationary phase culture supernatant accelerates growth of sputum cultures collected after initiation of anti-tuberculosis treatment.

    Science.gov (United States)

    Kolwijck, E; Friedrich, S O; Karinja, M N; van Ingen, J; Warren, R M; Diacon, A H

    2014-07-01

    We investigated the effect of Mycobacterium tuberculosis culture supernatant added to sputum cultures collected during the first 8 weeks of anti-tuberculosis treatment. With ongoing treatment duration, time to culture positivity decreased significantly in supernatant-enriched cultures, possibly due to stimulation of dormant or slowly metabolizing M. tuberculosis cells.

  3. A population-based case-control study of the safety of oral anti-tuberculosis drug treatment during pregnancy

    DEFF Research Database (Denmark)

    Czeizel, A.E.; Rockenbauer, M.; Olsen, J.;

    2001-01-01

    -control pairs did not indicate a teratogenic effect of these drugs in any group with congenital abnormality. CONCLUSION: Maternal exposure to oral anti-tuberculosis drugs during pregnancy did not show a detectable teratogenic risk to the fetus; however, the number of pregnant women who were treated...... Registry, between 1980 and 1996. Information on all oral anti-tuberculosis drug treatments during pregnancy was medically recorded. STUDY PARTICIPANTS: Women who had newborns or fetuses with congenital abnormalities (case group), and women who had babies with no congenital abnormality (control group). MAIN......; the corresponding figures for cases were 22,865 and 11 (0.05%). The prevalence odds ratio was 0.6 (95%CI 0.3-1.3). Analysis of isoniazid and other oral antituberculosis drug use during the second and third months of gestation, i.e., in the critical period for most major congenital abnormalities, in case...

  4. Prevention of hepatotoxicity due to anti tuberculosis treatment: A novel integrative approach

    Institute of Scientific and Technical Information of China (English)

    Meghna R Adhvaryu; Narsimha M Reddy; Bhasker C Vakharia

    2008-01-01

    AIM: To evaluate the ability of Curcuma longa (CL) and Tinospora cordifolia (TC) formulation to prevent anti-tuberculosis (TB) treatment (ATT) induced hepatotoxicity.METHODS: Patients with active TB diagnosis were randomized to a drug control group and a trial group on drugs plus an herbal formulation.Isoniazid,rifampicin,pyrazinamide and ethambutol for first 2 mo followed by continuation phase therapy excluding Pyrazinamide for 4 mo comprised the anti-tuberculous treatment.Curcumin enriched (25%) CL and a hydro-ethanolic extract enriched (50%) TC 1 g each divided in two doses comprised the herbal adjuvant.Hemogram,bilirubin and liver enzymes were tested initially and monthly till the end of study to evaluate the result.RESULTS: Incidence and severity of hepatotoxicity was significantly lower in trial group (incidence: 27/192 vs 2/316,P < 0.0001).Mean aspartate transaminase (AST) (195.93 ± 108.74 vs 85 ± 4.24,P < 0.0001),alanine transaminase (ALT) (75.74 ± 26.54 vs 41 ±1.41,P < 0.0001) and serum bilirubin (5.4 ± 3.38 vs 1.5± 0.42,P < 0.0001).A lesser sputum positivity ratio at the end of 4 wk (10/67 vs 4/137,P = 0.0068) and decreased incidence of poorly resolved parenchymal lesion at the end of the treatment (9/152 vs 2/278,P = 0.0037) was observed.Improved patient compliance was indicated by nil drop-out in trial vs 10/192 in control group (P < 0.0001).CONCLUSION: The herbal formulation prevented hepatotoxicity significantly and improved the disease outcome as well as patient compliance without any toxicity or side effects.

  5. A Study of the Timing of Death in Patients with Tuberculosis Who Die During Anti-Tuberculosis Treatment

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    Bhavik Patel

    2016-06-01

    Full Text Available Introduction: India has 2.0 million estimated tuberculosis (TB cases per annum with an estimated 280,000 TB related deaths per year. Understanding when in the course of TB treatment patients die is important for determining the type of intervention to be offered and crucially when this intervention should be given. The objectives of the current study were to determine in a large cohort of TB patients in India: - i treatment outcomes including the number who died while on treatment, ii the month of death and iii characteristics associated with and ldquo;early and rdquo; death, occurring in the initial 8 weeks of treatment. Methodology: This was a retrospective study in C.U.Shah Medical College and Hospital in Surendranagar, Gujarat India. A review was performed of treatment cards and medical records of all TB patients (adults and children registered and placed on standardized anti-tuberculosis treatment from January 2007 to April 2012. Results: There were 376 TB patients of whom 41 (11% were known to have died during treatment. Case-fatality was higher in those previously treated (24% and lower in those with extra-pulmonary TB (1%.Most of deaths during anti-tuberculosis treatment were early, with 66% of all patients dying in the first 8 weeks of treatment. Increasing age and new as compared to recurrent TB disease were significantly associated with and ldquo;early death and rdquo;. In this large cohort of TB patients, Most of deaths occurred early after starting anti-TB treatment. Reasons may relate to i the treatment of the disease itself, raising concerns about drug adherence, quality of anti-tuberculosis drugs or the presence of undetected drug resistance and ii co-morbidities, such as HIV/ AIDS and diabetes mellitus, which are known to influence mortality. iii Late stage presentation by patients themselves. More research in this area from prospective and retrospective studies is needed. [Natl J Med Res 2016; 6(2.000: 186-190

  6. Default from tuberculosis treatment in Tashkent, Uzbekistan; Who are these defaulters and why do they default?

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    Yuldashova Umida

    2008-07-01

    Full Text Available Abstract Background In Tashkent (Uzbekistan, TB treatment is provided in accordance with the DOTS strategy. Of 1087 pulmonary TB patients started on treatment in 2005, 228 (21% defaulted. This study investigates who the defaulters in Tashkent are, when they default and why they default. Methods We reviewed the records of 126 defaulters (cases and 132 controls and collected information on time of default, demographic factors, social factors, potential risk factors for default, characteristics of treatment and recorded reasons for default. Results Unemployment, being a pensioner, alcoholism and homelessness were associated with default. Patients defaulted mostly during the intensive phase, while they were hospitalized (61%, or just before they were to start the continuation phase (26%. Reasons for default listed in the records were various, 'Refusal of further treatment' (27% and 'Violation of hospital rules' (18% were most frequently recorded. One third of the recorded defaulters did not really default but continued treatment under 'non-DOTS' conditions. Conclusion Whereas patient factors such as unemployment, being a pensioner, alcoholism and homelessness play a role, there are also system factors that need to be addressed to reduce default. Such system factors include the obligatory admission in TB hospitals and the inadequately organized transition from hospitalized to ambulatory treatment.

  7. Sublineages of Mycobacterium tuberculosis Beijing genotype strains and unfavorable outcomes of anti-tuberculosis treatment.

    Science.gov (United States)

    Hang, Nguyen T L; Maeda, Shinji; Keicho, Naoto; Thuong, Pham H; Endo, Hiroyoshi

    2015-05-01

    The influence of Mycobacterium tuberculosis (MTB) lineages/sublineages on unfavorable tuberculosis (TB) treatment outcomes is poorly understood. We investigated the effects of Beijing genotype sublineages and other factors contributing to treatment outcome. Patients newly diagnosed with sputum smear-positive and culture-positive TB in Hanoi, Vietnam, participated in the study. After receiving anti-TB treatment, they were intensively followed up for the next 16 months. MTB isolates collected before treatment were subjected to drug susceptibility testing, and further analyzed to determine MTB (sub) lineages and their clonal similarities. Of 430 patients, 17 had treatment failure and 30 had TB recurrence. Rifampicin resistance was associated with treatment failure {adjusted odds ratio = 6.64 [95% confidence interval (CI), 1.48-29.73]}. The modern Beijing genotype was significantly associated with recurrent TB within 16 months [adjusted hazard ratio = 3.29 (95% CI, 1.17-9.27)], particularly after adjustment for the relevant antibiotic resistance. Human immunodeficiency virus coinfection and severity on chest radiographs were not significantly associated with unfavorable outcomes. Our findings provide further understanding of the influence of MTB strains on unfavorable treatment outcomes. Multiple risk factors should be considered for the optimal management of TB. PMID:25732626

  8. Determinants of poor adherence to anti-tuberculosis treatment in Mumbai, India

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    Suparna Bagchi

    2010-01-01

    Conclusions: An approach, targeting easier access to drugs, an ensured drug supply, effective solutions for travel-related concerns and modification of smoking and alcohol related behaviors are essential for treatment adherence.

  9. Factors Associated with Fatality during the Intensive Phase of Anti-Tuberculosis Treatment

    Science.gov (United States)

    Casals, M.; Caminero, J. A.; García-García, J. M.; Jiménez-Fuentes, M. A.; Medina, J. F.; Millet, J. P.; Ruiz-Manzano, J.; Caylá, J.

    2016-01-01

    Objective To determine the case-fatality rate (CFR) at the end of the intensive phase of tuberculosis (TB) treatment, and factors associated with fatality. Methods TB patients diagnosed between 2006 and 2013 were followed-up during treatment. We computed the CFR at the end of the intensive phase of TB treatment, and the incidence of death per 100 person-days (pd) of follow-up. We performed survival analysis using the Kaplan-Meier method and Cox regression, and calculate hazard ratios (HR) and 95% confidence intervals (CI). Results A total of 5,182 patients were included, of whom 180 (3.5%) died; 87 of these deaths (48.3%) occurred during the intensive phase of treatment, with a CFR of 1.7%. The incidence of death was 0.028/100 pd. The following factors were associated with death during the intensive phase: being >50 years (HR = 36.9;CI:4.8–283.4); being retired (HR = 2.4;CI:1.1–5.1); having visited the emergency department (HR = 3.1;CI:1.2–7.7); HIV infection (HR = 3.4;CI:1.6–7.2); initial standard treatment with 3 drugs (HR = 2.0;CI:1.2–3.3) or non-standard treatments (HR = 2.68;CI:1.36–5.25); comprehension difficulties (HR = 2.8;CI:1.3–6.1); and smear-positive sputum (HR = 2.3-CI:1.0–4.8). Conclusion There is a non-negligible CFR during the intensive phase of TB, whose reduction should be prioritised. The CFR could be a useful indicator for evaluating TB programs. PMID:27487189

  10. Mobile phone text messaging for promoting adherence to anti-tuberculosis treatment: a systematic review protocol

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    Nglazi Mweete D

    2013-01-01

    Full Text Available Abstract Background In 2010, there were approximately 8.8 million incident cases of tuberculosis (TB worldwide. The treatment of TB is at least six months long and may be complicated by a high pill burden. In addition, TB patients often do not take their medication on schedule simply because they forget. Mobile phone text messaging has the potential to help promote TB treatment adherence. We, therefore, propose to conduct a review of current best evidence for the use of mobile phone text messaging to promote patient adherence to TB treatment. Methods This is a systematic review of the literature. We will preferably include randomized controlled trials (RCTs. However, non-randomized studies (NRS will be considered if there is an inadequate number of RCTs. We will search PubMed, EMBASE, CINAHL, CENTRAL, Science Citation Index, Africa-Wide Information, and WHOLIS electronic databases for eligible studies available by 30 November 2012 regardless of language or publication status. We will also check reference lists for additional studies, identify abstracts from conference proceedings and communicate with authors for any relevant material. At least two authors will independently screen search outputs, select studies, extract data and assess the risk of bias (using separate criteria for RCTs and NRS; resolving discrepancies by discussion and consensus. We will assess clinical heterogeneity by examining the types of participants, interventions and outcomes in each study and pool studies judged to be clinically homogenous. We will also assess statistical heterogeneity using the chi-square test of homogeneity and quantify it using the I-square statistic. If study results are found to be statistically homogeneous (that is heterogeneity P > 0.1, we will pool them using the fixed-effect meta-analysis. Otherwise, we will use random-effects meta-analysis. We will calculate risk ratios and their corresponding 95% confidence intervals for dichotomous outcomes

  11. Factors associated with default from treatment among tuberculosis patients in nairobi province, Kenya: A case control study

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    Ombeka Victor O

    2011-09-01

    Full Text Available Abstract Background Successful treatment of tuberculosis (TB involves taking anti-tuberculosis drugs for at least six months. Poor adherence to treatment means patients remain infectious for longer, are more likely to relapse or succumb to tuberculosis and could result in treatment failure as well as foster emergence of drug resistant tuberculosis. Kenya is among countries with high tuberculosis burden globally. The purpose of this study was to determine the duration tuberculosis patients stay in treatment before defaulting and factors associated with default in Nairobi. Methods A Case-Control study; Cases were those who defaulted from treatment and Controls those who completed treatment course between January 2006 and March 2008. All (945 defaulters and 1033 randomly selected controls from among 5659 patients who completed treatment course in 30 high volume sites were enrolled. Secondary data was collected using a facility questionnaire. From among the enrolled, 120 cases and 154 controls were randomly selected and interviewed to obtain primary data not routinely collected. Data was analyzed using SPSS and Epi Info statistical software. Univariate and multivariate logistic regression analysis to determine association and Kaplan-Meier method to determine probability of staying in treatment over time were applied. Results Of 945 defaulters, 22.7% (215 and 20.4% (193 abandoned treatment within first and second months (intensive phase of treatment respectively. Among 120 defaulters interviewed, 16.7% (20 attributed their default to ignorance, 12.5% (15 to traveling away from treatment site, 11.7% (14 to feeling better and 10.8% (13 to side-effects. On multivariate analysis, inadequate knowledge on tuberculosis (OR 8.67; 95% CI 1.47-51.3, herbal medication use (OR 5.7; 95% CI 1.37-23.7, low income (OR 5.57, CI 1.07-30.0, alcohol abuse (OR 4.97; 95% CI 1.56-15.9, previous default (OR 2.33; 95% CI 1.16-4.68, co-infection with Human immune

  12. Effect of scheduled monitoring of liver function during anti-Tuberculosis treatment in a retrospective cohort in China

    OpenAIRE

    Wu Shanshan; Xia Yinyin; Lv Xiaozhen; Zhang Yuan; Tang Shaowen; Yang Zhirong; Tu Dehua; Deng Peiyuan; Cheng Shiming; Wang Xiaomeng; Yuan Yanli; Liu Feiying; Hu Daiyu; Zhan Siyan

    2012-01-01

    Abstract Background Data on effect of regular liver function monitoring during anti-TB treatment is limited in China. This study aimed to evaluate the effects of scheduled liver function monitoring on identification of asymptomatic liver damage and anti-TB treatment outcomes during anti-TB treatment. Methods A retrospective analysis was performed based on a national-level cohort study. A total of 273 patients developing liver dysfunction were divided into two groups, 111 patients who were dia...

  13. Duration of Anti-Tuberculosis Therapy and Timing of Antiretroviral Therapy Initiation: Association with Mortality in HIV-Related Tuberculosis

    Science.gov (United States)

    Cortes, Claudia P.; Wehbe, Firas H.; McGowan, Catherine C.; Shepherd, Bryan E.; Duda, Stephany N.; Jenkins, Cathy A.; Gonzalez, Elsa; Carriquiry, Gabriela; Schechter, Mauro; Padgett, Denis; Cesar, Carina; Madero, Juan Sierra; Pape, Jean W.; Masys, Daniel R.; Sterling, Timothy R.

    2013-01-01

    Background Antiretroviral therapy (ART) decreases mortality risk in HIV-infected tuberculosis patients, but the effect of the duration of anti-tuberculosis therapy and timing of anti-tuberculosis therapy initiation in relation to ART initiation on mortality, is unclear. Methods We conducted a retrospective observational multi-center cohort study among HIV-infected persons concomitantly treated with Rifamycin-based anti-tuberculosis therapy and ART in Latin America. The study population included persons for whom 6 months of anti-tuberculosis therapy is recommended. Results Of 253 patients who met inclusion criteria, median CD4+ lymphocyte count at ART initiation was 64 cells/mm3, 171 (68%) received >180 days of anti-tuberculosis therapy, 168 (66%) initiated anti-tuberculosis therapy before ART, and 43 (17%) died. In a multivariate Cox proportional hazards model that adjusted for CD4+ lymphocytes and HIV-1 RNA, tuberculosis diagnosed after ART initiation was associated with an increased risk of death compared to tuberculosis diagnosis before ART initiation (HR 2.40; 95% CI 1.15, 5.02; P = 0.02). In a separate model among patients surviving >6 months after tuberculosis diagnosis, after adjusting for CD4+ lymphocytes, HIV-1 RNA, and timing of ART initiation relative to tuberculosis diagnosis, receipt of >6 months of anti-tuberculosis therapy was associated with a decreased risk of death (HR 0.23; 95% CI 0.08, 0.66; P=0.007). Conclusions The increased risk of death among persons diagnosed with tuberculosis after ART initiation highlights the importance of screening for tuberculosis before ART initiation. The decreased risk of death among persons receiving > 6 months of anti-tuberculosis therapy suggests that current anti-tuberculosis treatment duration guidelines should be re-evaluated. PMID:24066096

  14. Treatment default amongst patients with tuberculosis in urban Morocco: predicting and explaining default and post-default sputum smear and drug susceptibility results.

    Directory of Open Access Journals (Sweden)

    Imad Cherkaoui

    Full Text Available SETTING: Public tuberculosis (TB clinics in urban Morocco. OBJECTIVE: Explore risk factors for TB treatment default and develop a prediction tool. Assess consequences of default, specifically risk for transmission or development of drug resistance. DESIGN: Case-control study comparing patients who defaulted from TB treatment and patients who completed it using quantitative methods and open-ended questions. Results were interpreted in light of health professionals' perspectives from a parallel study. A predictive model and simple tool to identify patients at high risk of default were developed. Sputum from cases with pulmonary TB was collected for smear and drug susceptibility testing. RESULTS: 91 cases and 186 controls enrolled. Independent risk factors for default included current smoking, retreatment, work interference with adherence, daily directly observed therapy, side effects, quick symptom resolution, and not knowing one's treatment duration. Age >50 years, never smoking, and having friends who knew one's diagnosis were protective. A simple scoring tool incorporating these factors was 82.4% sensitive and 87.6% specific for predicting default in this population. Clinicians and patients described additional contributors to default and suggested locally-relevant intervention targets. Among 89 cases with pulmonary TB, 71% had sputum that was smear positive for TB. Drug resistance was rare. CONCLUSION: The causes of default from TB treatment were explored through synthesis of qualitative and quantitative data from patients and health professionals. A scoring tool with high sensitivity and specificity to predict default was developed. Prospective evaluation of this tool coupled with targeted interventions based on our findings is warranted. Of note, the risk of TB transmission from patients who default treatment to others is likely to be high. The commonly-feared risk of drug resistance, though, may be low; a larger study is required to confirm

  15. Hematological and liver toxicity of anti-tuberculosis drugs

    Science.gov (United States)

    Mirlohi, Maryam-Sadat; Ekrami, Alireza; Shirali, Saeed; Ghobeishavi, Mehdi; Pourmotahari, Fatemeh

    2016-01-01

    Introduction Tuberculosis (TB) is a major global health problem, and anti-tuberculosis drugs can cause severe adverse reactions. The aim of this study was to determine hematological and biochemical changes and associated risk factors in smear positive pulmonary tuberculosis patients undergoing treatment with standard protocols. Methods In a descriptive study, a total of 40 tuberculosis patients aged between 15–60 years were collected from hospitals in Khuzestan Province (Iran) from March 2013 to March 2014. The patients were treated with drugs (isoniazid, rifampicin, ethambutol, and pyrazinamide) during the initial two months, followed by isoniazid and rifampicin for the next four to six months. Activities of liver enzymes (ALT, AST, and ALP) and hematological parameters were recorded before and after treatment. Data were analyzed using paired samples t-test and Wilcoxon test by SPSS 16. Results After using drug treatments, hematological parameters (RBC, Hb, HCT, MCV, MCH, and MCHC), except platelet count, were changed significantly (p ≤ 0.001). Liver enzyme activities (ALT, AST, and ALP) were decreased significantly (p ≤ 0.001) after treatment. Conclusion In this study, changes of hematological and biochemical parameters have been observed in patients with pulmonary tuberculosis. It can be concluded that the anti-tuberculosis treatment is associated with changes of hematological parameters and liver enzymes.

  16. Anti-tuberculosis drugs related hepatotoxicity; incidence, risk factors, pattern of changes in liver enzymes and outcome

    Directory of Open Access Journals (Sweden)

    H Khalili

    2009-10-01

    Full Text Available "nBackground and the purpose of the study: Tuberculosis is a curable disease if diagnosed and treated properly with anti-tuberculosis drugs. These drugs can cause severe adverse reactions including hepatotoxicity.The goal of this study was to evaluate the rate and the time of incidence, pattern of alterations in liver enzyme, risk factors and outcome of anti-tuberculosis drugs induced hepatotoxicity in Iranian Tuberculosis patients. "nMethod: In a prospective cohort study, 102 patients (68 male, 34 female, mean age 43.21±18 years with tuberculosis diagnosis were followed during anti-tuberculosis drug treatment course. Drug related hepatotoxicity was defined as increase in serum alanine aminotransfrase or aspartate aminotransfrase greater than three or five times of the upper limit of normal, with or without symptoms of hepatitis, respectively. "nResults: anti-tuberculosis induced hepatotoxicity was detected in 32 (31.37% of the patients. Human immunodeficiency virus and hepatitis C virus infections, concomitant use of hepatotoxic drugs, and abnormal baseline serum alanine aminotransfrase and aspartate aminotransfrase level were risk factors for anti-tuberculosis drugs induced hepatotoxicity. "nConclusion: Anti-tuberculosis drugs induced hepatotoxicity is a major problem in Iranian tuberculosis patients and cause treatment interruption in 31.37% of patients.

  17. Non-adherence to anti-tuberculosis treatment among internal migrants with pulmonary tuberculosis in Shenzhen, China: a cross-sectional study

    OpenAIRE

    Tang, Ying; Zhao, Meigui; Wang, Yunxia; Gong, Yanhong; Yin, Xiaoxv; Zhao, Angui; Zheng, Juanjuan; Liu, Zhenyang; Jian, Xiaofang; Wang, Wenxin; Wu, Chunmei; Lu, Zuxun

    2015-01-01

    Background Non-adherence to tuberculosis (TB) treatment threatens the success of treatment, increases the risk of TB spread, and leads to the development of drug resistance. The present study assessed non-adherence to anti-TB treatment among internal migrants with pulmonary TB living in Shenzhen, China, and examined risk factors for non-adherence in order to identify targets for intervention. Methods A total of 794 internal migrants with TB treated at Bao’an Hospital for Chronic Disease Preve...

  18. Treatment default and death among tuberculosis patients in Hunan, China.

    Science.gov (United States)

    Abuaku, Benjamin; Tan, Hongzhuan; Li, Xingli; Chen, Mengshi; Huang, Xin

    2010-04-01

    We used the 2005 and 2006 national surveillance data to elucidate some of the risk factors for treatment default and death among tuberculosis (TB) patients in Hunan, China. Risk of default was higher in males (odds ratio (OR) 1.25; 95% confidence interval (CI) 1.08, 1.44); lowest in patients aged 15-24 y (OR 0.60; 95% CI 0.49, 0.75), and generally increased with increasing age; lower in patients living in cities with per capita gross domestic product (GDP) of less than 1000 US$ (OR 0.60, 95% CI 0.49, 0.72), and increased with increasing per capita GDP of city of residence; and higher in patients with previously treated smear-positive pulmonary TB (diagnostic category II according to the World Health Organization definition; OR 1.99; 95% CI 1.22, 3.23). Risk of death was lowest in patients aged 15-24 y (OR 0.07; 95% CI 0.05, 0.10), and increased with increasing age; lower in new cases (OR 0.50; 95% CI 0.33, 0.76); and highest in patients who treated themselves (OR 3.47; 95% CI 1.27, 9.46). We conclude that male TB patients, elderly TB patients, patients resident in cities with higher per capita GDP, and patients receiving category II treatment need special attention to reduce TB treatment default in the province. Furthermore, elderly TB patients and patients with a long history of TB need special attention to reduce mortality. Self-treatment also needs to be discouraged to reduce mortality.

  19. Risk Factors for DOTS Treatment Default Among New HIV-TB Coinfected Patients in Nalgonda (Dist.) Telangana (State): A Case Control Study

    Science.gov (United States)

    Reddy Satti, Siva Balaji; Kondagunta, Nagaraj

    2016-01-01

    Background: The therapeutic regimens as recommended by the Revised National TB Control Programme (RNTCP) have been shown to be highly effective for both preventing and treating tuberculosis, but poor adherence to medication is a major barrier to its global control. Aim and Objectives: The study was conducted to assess the influence of patient related factors for DOTS Treatment Default among HIV-TB Co-infected cases. Setting and Design: This was a case control study conducted in Nalgond, Telangana. Materials and Methods: All new HIV-TB coinfected and DOTS-defaulted patients registered under RNTCP for the period from January 2010 to December 2012 were selected. Of the 154 patients, 23 had died and 11 could not be traced, and these were excluded. Thus the total number of available cases were 120 for those age- and sex-matched controls (HIV-TB coinfected patients and those who had completed the DOTS regimen successfully) were selected. Results: The mean age was 36.5 ± 9 years; the majority (23.3%) of patients defaulted during the second month of treatment. Significant risk factors associated with defaulting included unskilled occupation [adjusted odds ratio (AOR: 3.56; 95% confidence interval (CI): 1.1-11.56], lower middle class socioeconomic status (AOR: 17.16; 95% CI: 3.93-74.82), small family size (AOR: 21.3; 95% CI: 6.4-70.91), marital disharmony (AOR: 6.78; 95% CI: 1.93-23.76), not being satisfied with the conduct of health personnel (AOR: 7.38; 95% CI: 2.32-23.39), smoking (AOR: 8.5; 95% CI: 2.31-31.21), and side effects of drugs (AOR: 4.18; 95% CI: 1.35-12.9). Conclusion: Unskilled occupation, marital disharmony, small family size, lower middle class socioeconomic status, not being satisfied with the conduct of health personnel, smoking, and drug side effects were significantly associated with defaulting. Information on the pattern of tuberculosis (TB), the outcome of anti-tuberculosis treatment (ATT), and the factors associated with it will help in planning

  20. Eficacia y eficiencia del tratamiento antituberculoso en jurisdicciones sanitarias de Morelos Efficacy and efficiency of anti-tuberculosis treatment in 2 sanitary jurisdictions of Morelos, Mexico

    Directory of Open Access Journals (Sweden)

    Ma. de Lourdes García-García

    1998-09-01

    Full Text Available Objetivo. Evaluar la eficacia y la eficiencia del tratamiento antituberculoso administrado por la Secretaría de Salud (SSA en las jurisdicciones sanitarias de Cuernavaca y Cuautla, estado de Morelos, en el periodo 1992-1996. Material y métodos. Se hizo una revisión retrospectiva de las tarjetas de control de tratamiento en pacientes tuberculosos. Se utilizaron las definiciones contenidas en la Norma Oficial para el Control y Prevención de la Tuberculosis en la Atención Primaria a la Salud. La información fue vaciada en formatos estandarizados y se analizó mediante el programa SAS y Epi Info. Se visitaron las 149 unidades de atención primaria y los cuatro hospitales de la zona de estudio. Resultados. Se encontraron las tarjetas correspondientes a 288 pacientes, de los cuales 260 eran de casos nuevos. Estos pacientes recibieron en conjunto 311 tratamientos, de los cuales 85% fueron supervisados. Las tarjetas revisadas correspondieron al 60% de los casos notificados por la SSA en el mismo periodo. El grupo de pacientes tuberculosos tuvo mayor edad que la media poblacional y mayor probabilidad de pertenecer a los estratos socioeconómicos medio y bajo que la población general del área. Se analizaron 246 esquemas de tratamiento y se encontró que 32% presentó curación bacteriológica; 26%, curación probable; 18% abandonó el tratamiento; 1% fracasó en el tratamiento, y 3% murió durante el tratamiento. En 20% de los casos se desconoció el resultado del tratamiento. La frecuencia de curación fue mayor en los casos nuevos (61% que en los retratamientos (38% (pObjective. To evaluate the efficacy and efficiency of tuberculosis treatment administered by the Secretaría de Salud (SSA in the sanitary jurisdictions of Cuernavaca and Cuautla, Morelos, for the 1992-1996 period by retrospectively reviewing tuberculosis treatment control cards. Material and methods. Official Norm for Tuberculosis Prevention and Control in Primary Care Units

  1. TSH-CHECK-1 test: diagnostic accuracy and potential application to initiating treatment for hypothyroidism in patients on anti-tuberculosis drugs.

    Directory of Open Access Journals (Sweden)

    Cara S Kosack

    Full Text Available BACKGROUND: Thyroid-stimulating hormone (TSH promotes expression of thyroid hormones which are essential for metabolism, growth, and development. Second-line drugs to treat tuberculosis (TB can cause hypothyroidism by suppressing thyroid hormone synthesis. Therefore, TSH levels are routinely measured in TB patients receiving second-line drugs, and thyroxin treatment is initiated where indicated. However, standard TSH tests are technically demanding for many low-resource settings where TB is prevalent; a simple and inexpensive test is urgently needed. METHODS: As a proof of concept study TSH was measured in routinely collected sera at the University Medical Center Utrecht, Netherlands, using the TSH-CHECK-1 (VEDALAB, Alençon, France, a lateral-flow rapid immunochromatographic assay with a TSH cut-off value of 10 µIU/mL, the standard threshold for initiating treatment. These results were compared with TSH levels measured by a reference standard (UniCel DXi 800 imunoassay system, Beckman Coulter, USA. Sensitivity, specificity, and likelihood ratios were then calculated. RESULTS: A total of 215 serum samples were evaluated: 107 with TSH values <10 µIU/mL and 108 with values ≥10 µIU/mL. TSH-CHECK-1 test sensitivity was found to be 100.0% (95% CI: 96.6-100.0 and specificity was 76.6% (95% CI: 67.5-84.3. Predictive values (PV were modelled for different levels of prevalence. For a prevalence of 10% and 50%, the positive PV was 32.2% (95% CI: 25.0-39.7% and 81.1% (95% CI: 75.0-85.5%, respectively; the negative PV was 100% (95% CI: 98.9-100% and 100% (95% CI: 91.3-100% respectively. DISCUSSION/CONCLUSIONS: The TSH-CHECK-1 rapid test was practical and simple to perform but difficult to interpret on weak positive results. All sera with TSH≥10 µIU/mL were correctly identified, but the test lacked sufficient specificity. Given its excellent negative PV in this evaluation, the test shows promise for ruling out hypothyroidism. However, so far it

  2. Evaluación del tratamiento antituberculoso en la zona norte del conurbano bonaerense Anti- tuberculosis treatment evaluation in Northern districts of Buenos Aires suburbs

    Directory of Open Access Journals (Sweden)

    Cristina Chirico

    2007-04-01

    Full Text Available El objetivo del presente estudio fue analizar el impacto epidemiológico producido por la aplicación de la estrategia del tratamiento para tuberculosis (TB de corta duración y directamente observado (DOTS, y su correlación con el éxito en la Región Sanitaria V, durante el año 2003. Se evaluó la curación comparando dos grupos de estudio. Grupo 1: municipios con 65% o más de los casos con DOTS, y Grupo 2: con 64% o menos de los pacientes bajo esta estrategia o sin su aplicación. Se analizó la letalidad global y de pacientes HIV (+ en ambos grupos. En el grupo 1 el éxito del tratamiento fue 85.7%, con curación en las formas pulmonares confirmadas de 86.2% y abandono de 8.8%. En el grupo 2 la curación alcanzó el 67.6%, en pulmonares confirmados 68.1% y el abandono de 21.8%. La letalidad global fue 5.2%, en pacientes HIV (+ 22.3% y en los HIV (- 4.1%. La curación en TB/HIV en el grupo 1 fue 55.2%, con abandono de 6.9%; en el grupo 2 curó el 46.4% y abandonó el 19.7%. El 31.0% de pacientes HIV (+ fallecieron en el grupo 1 y 16.1% en el grupo 2. La implementación del DOTS, permitió alcanzar la meta de curar el 85% de los casos, probando ser una herramienta eficaz, capaz de garantizar la curación de la mayoría de los pacientes y reducir el riesgo de enfermar de la comunidad.The aim of this study was to analyze the epidemiologic impact produced by Direct Observed Treatment Strategy (DOTS application regarding to its success in the 5th Sanitary Region during the year 2 003. The cure was evaluated by a cohort study comparing two groups. Group 1: Districts in which DOTS were applied in 65% or more TB patients; group 2: Districts applying DOTS in 64% or less, or without its implementation. The global mortality was analyzed on HIV (- as well as on HIV (+ patients in both groups. In Municipalities where DOTS strategy was applied in >65% of notified cases, the treatment success was 85.7%; the cure rate of bacteriological confirmed

  3. Hepatitis B or hepatitis C co-infection in individuals infected with human immunodeficiency virus and effect of anti-tuberculosis drugs on liver function

    OpenAIRE

    Padmapriyadarsini C; Chandrabose J; Victor L; Hanna L; Arunkumar N; Swaminathan Soumya

    2006-01-01

    Background: Tuberculosis (TB) and hepatitis are the two common co-infections in patients infected with human immunodeficiency virus (HIV). Anti-tuberculosis treatment (ATT) may have an effect on the liver enzymes in these co-infected HIV patients. Aims: To determine the prevalence of Hepatitis B and C virus coinfection in HIV infected patients in Tamilnadu and assess effects of anti-tuberculosis drugs on their liver function. Settings: HIV positive subjects referred to the Tuberculosis R...

  4. Silymarin protects liver against toxic effects of anti-tuberculosis drugs in experimental animals

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    Izzettin Fikret V

    2008-07-01

    Full Text Available Abstract Background The first line anti-tuberculosis drugs isoniazid (INH, rifampicin (RIF and pyrazinamide (PZA continues to be the effective drugs in the treatment of tuberculosis, however, the use of these drugs is associated with toxic reactions in tissues, particularly in the liver, leading to hepatitis. Silymarin, a standard plant extract with strong antioxidant activity obtained from S. marianum, is known to be an effective agent for liver protection and liver regeneration. The aim of this study was to investigate the protective actions of silymarin against hepatotoxicity caused by different combinations of anti-tuberculosis drugs. Methods Male Wistar albino rats weighing 250–300 g were used to form 6 study groups, each group consisting of 10 rats. Animals were treated with intra-peritoneal injection of isoniazid (50 mg/kg and rifampicin (100 mg/kg; and intra-gastric administration of pyrazinamid (350 mg/kg and silymarin (200 mg/kg. Hepatotoxicity was induced by a combination of drugs with INH+RIF and INH+RIF+PZA. Hepatoprotective effect of silymarin was investigated by co-administration of silymarin together with the drugs. Serum biochemical tests for liver functions and histopathological examination of livers were carried out to demonstrate the protection of liver against anti-tuberculosis drugs by silymarin. Results Treatment of rats with INH+RIF or INH+RIF+PZA induced hepatotoxicity as evidenced by biochemical measurements: serum alanine aminotransferase (ALT, aspartate aminotransferase (AST and alkaline phosphatase (ALP activities and the levels of total bilirubin were elevated, and the levels of albumin and total protein were decreased in drugs-treated animals. Histopathological changes were also observed in livers of animals that received drugs. Simultaneous administration of silymarin significantly decreased the biochemical and histological changes induced by the drugs. Conclusion The active components of silymarin had

  5. 抗病毒联合抗结核药物在艾滋病合并肺结核患者治疗中应用分析%Analysis of the application of anti-virus combined with anti-tuberculosis drugs in the treatment of acquired immune deficiency syndrome complicated with pulmonary tuberculosis

    Institute of Scientific and Technical Information of China (English)

    贾中毅

    2015-01-01

    Objective:To explore the application effect of anti-virus combined with anti-tuberculosis drugs in the treatment of acquired immune deficiency syndrome complicated with pulmonary tuberculosis.Methods:32 patients with AIDS combined with tuberculosis were selected.They were given AZT+NVP+DDI antiviral regimen and 2H3R3Z3E3/7H3R3 regimen for tuberculosis treatment.We compared the treatment effect.Results:In 23 cases of HIV/AIDS/TB double infections,15 cases were clinically cured;5 cases completed one course;chest X-ray of 3 cases showed focus was absorbed and they continued to take medicine.Compared with before treatment,the CD4+T lymphocyte count at 6 months and 9 months after treatment was significantly improved(P<0.05). Conclusion:The dual anti infection treatment program of anti tuberculosis and anti-virus can effectively control tuberculosis and improve the immunity of HIV patients.%目的:探讨抗病毒联合抗结核药物在艾滋病合并肺结核患者治疗中应用效果。方法:收治艾滋病合并肺结核患者32例,采用AZT+NVP+DDI抗病毒方案治疗及2H3R3Z3E3/7H3R3抗结核方案治疗,比较治疗效果。结果:23例HIV/AIDS/TB双重感染患中,15例临床治愈,5例完成1个疗程,3例胸片提示病灶吸收好转继续服药。治疗6个月、9个月的CD4+T淋巴细胞计数较治疗前均有明显提高(P<0.05)。结论:该抗结核抗病毒双重抗感染治疗方案,可达到有效控制结核病,提高HIV患者免疫力。

  6. Patients with secondary amenorrhea due to tuberculosis endometritis towards the induced anti-tuberculosis drug category 1.

    Science.gov (United States)

    Perdhana, Raditya; Sutrisno, Sutrisno; Sugiri, Yani Jane; Baktiyani, Siti Candra Windu; Wiyasa, Arsana

    2016-01-01

    Tuberculosis (TB) is a disease which can affect various organs, including human's genital organs such as the endometrium. Tuberculosis endometritis can cause clinical symptoms of secondary amenorrhea and infertility. Infertility in genital TB caused by the involvement of the endometrium. The case presentation is 33-year-old woman from dr. Saiful Anwar Public Hospital to consult that she has not menstruated since 5 years ago (28 years old). The diagnosis was done by performing a clinical examination until the diagnosis of secondary amenorrhea due to tuberculosis endometritis is obtained. A treatment by using category I of anti-tuberculosis drugs was done for 6 months, afterward an Anatomical Pathology observation found no signs of the tuberculosis symptoms. Based on that, patient, who was diagnosed to have secondary amenorrhea due to tuberculosis endometritis, has no signs of tuberculosis process after being treated by using category I of anti-tuberculosis drugs for 6 months. PMID:27642459

  7. Risk factors of treatment default and death among tuberculosis patients in a resource-limited setting

    Institute of Scientific and Technical Information of China (English)

    Isaac Alobu; Sarah N Oshi; Daniel C Oshi; Kingsley N Ukwaja

    2014-01-01

    Objective:To evaluate the rates, timing and determinants of default and death among adult tuberculosis patients inNigeria.Methods:Routine surveillance data were used.A retrospective cohort study of adult tuberculosis patients treated during2011 and2012 in two large health facilities inEbonyiState,Nigeria was conducted.Multivariable logistic regression analyses were used to identify independent predictors for treatment default and death.Results:Of1668 treated patients, the default rate was157(9.4%), whilst165(9.9%) died.Also,35.7%(56) of the treatment defaults and151(91.5%) of deaths occurred during the intensive phase of treatment.Risk of default increased with increasing age(adjusted odds ratio(aOR)1.2;95% confidence interval(CI) 1.1-1.9), smear-negativeTB case(aOR2.3;CI1.5-3.6), extrapulmonaryTB case(aOR2.7;CI1.3-5.2), and patients who received the longer treatment regimen(aOR1.6;1.1-2.2).Risk of death was highest in extrapulmonaryTB(aOR3.0;CI1.4-6.1) and smear-negativeTB cases(aOR2.4;CI 1.7-3.5), rural residents(aOR1.7;CI1.2-2.6),HIV co-infected(aOR2.5;CI1.7-3.6), not receiving antiretroviral therapy(aOR1.6;CI1.1-2.9), and not receivingcotrimoxazole prophylaxis(aOR1.7;CI1.2-2.6).Conclusions:Targeted interventions to improve treatment adherence for patients with the highest risk of default or death are urgently needed.This needs to be urgently addressed by theNationalTuberculosisProgramme.

  8. Nine- to Twelve-Month Anti-Tuberculosis Treatment Is Associated with a Lower Recurrence Rate than 6–9-Month Treatment in Human Immunodeficiency Virus-Infected Patients: A Retrospective Population-Based Cohort Study in Taiwan

    OpenAIRE

    Jann-Yuan Wang; Hsin-Yun Sun; Jann-Tay Wang; Chien-Ching Hung; Ming-Chih Yu; Chih-Hsin Lee; Li-Na Lee

    2015-01-01

    Background Human immunodeficiency virus (HIV)-infected patients are at an increased risk of tuberculosis (TB) and its recurrence following completion of anti-TB treatment. We investigated whether extending anti-TB treatment to 9 months or longer reduces TB recurrence. Methods HIV-infected patients who were diagnosed with pulmonary TB between 1997 and 2009 and who received anti-TB treatment for a duration between 5.5 and 12.5 months were identified from the National Health Insurance Research D...

  9. The search for new sterilizing anti-tuberculosis drugs.

    Science.gov (United States)

    Mitchison, Denis A

    2004-05-01

    To be of use in the control of tuberculosis, any new drug must be capable of shortening the duration of treatment by accelerating sterilizing activity, that is the rate at which Mycobacterium tuberculosis is killed in the lesions. The most difficult to kill are the extra-cellular bacilli in cavities. Persistence during therapy arises because there is a proportion of slowly metabolising bacilli (persisters) in the cavitary bacterial population at the start of treatment. Bacterial growth is slowed by low oxygen tension, quorum sensing and old age, but probably not by cellular immunity, since there are few professional phagocytic cells in cavities. The degree of phenotypic resistance to the bactericidal action of drugs can go through several stages: (i) the non-replicating stages 1 and 2 of micro-aerophilic adaptation, described by Wayne; (ii) a "tolerant" population that survives exposure to high rifampicin concentrations and is capable of growth in liquid medium but not on solid medium; and (iii) a population found in the sterile state of Cornell model mice which cannot grow initially in either liquid or solid medium but will eventually cause re-activation of tuberculosis. In all of these stages the bacilli are phenotypically resistant; there is no selection for genomic drug resistance. Rifampicin and pyrazinamide are the two drugs largely responsible for sterilizing activity during current treatment. Pyrazinamide is unique amongst anti-tuberculosis drugs in having no genomic site of action and having greater bactericidal activity as bacillary metabolism slows down; it is remarkably effective in human disease. The development of a new drug with a similar mode of activity might be very fruitful, especially if there were no need for an acid environment. Current methods advocated for drug development pass through a number of complex stages: choice of a genomic target, development of an in vitro assay, high throughput screening and identification of lead compounds

  10. TREATMENT COMPLIANCE OF PATIENTS ON DOTS UNDER RNTCP IN DISTRICT PULWAMA (KASHMIR, WITH SPECIAL REFRENCE TO DEFAULTERS

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    Rifat

    2015-09-01

    Full Text Available Defaulters from tuberculosis treatment are at risk for clinical deterioration and complications including MDR , XDR and death. The objectives of the study were to identify various risk factors associated with Tuberculosis default patients& to assess the timing & pattern of treatment interruption. For this cross sectional study eligible patients for the study include d TB patients ( N ew cases or defaulters , Patients were identified from the TCU registers and Contacted to answer a questionnaire. For each case two defaulters were also interviewed on already formulated; pretested questionnaire in their respective homes. R elevant DOTS providers were also interviewed. Four TB default patients were found registered during study period of one year in district Pulwama & eight non - defaulters ( T reatment completed/cured . Major reasons for default included side effects of anti TB drugs , patients put on non - DOTS & patients beginning to feel better/cured. The high prevalence of TB default patients mandates interventions in the form of introducing Non - DOTS under RNTCP , improving health education regarding benefits of treatment complet ion by DOTS staff.

  11. Determinants of Default from Tuberculosis Treatment among Patients with Drug-Susceptible Tuberculosis in Karachi, Pakistan: A Mixed Methods Study

    Science.gov (United States)

    Chida, Natasha; Ansari, Zara; Hussain, Hamidah; Jaswal, Maria; Symes, Stephen; Khan, Aamir J.; Mohammed, Shama

    2015-01-01

    Purpose Non-adherence to tuberculosis therapy can lead to drug resistance, prolonged infectiousness, and death; therefore, understanding what causes treatment default is important. Pakistan has one of the highest burdens of tuberculosis in the world, yet there have been no qualitative studies in Pakistan that have specifically examined why default occurs. We conducted a mixed methods study at a tuberculosis clinic in Karachi to understand why patients with drug-susceptible tuberculosis default from treatment, and to identify factors associated with default. Patients attending this clinic pick up medications weekly and undergo family-supported directly observed therapy. Methods In-depth interviews were administered to 21 patients who had defaulted. We also compared patients who defaulted with those who were cured, had completed, or had failed treatment in 2013. Results Qualitative analyses showed the most common reasons for default were the financial burden of treatment, and medication side effects and beliefs. The influence of finances on other causes of default was also prominent, as was concern about the effect of treatment on family members. In quantitative analysis, of 2120 patients, 301 (14.2%) defaulted. Univariate analysis found that male gender (OR: 1.34, 95% CI: 1.04–1.71), being 35–59 years of age (OR: 1.54, 95% CI: 1.14–2.08), or being 60 years of age or older (OR: 1.84, 95% CI: 1.17–2.88) were associated with default. After adjusting for gender, disease site, and patient category, being 35–59 years of age (aOR: 1.49, 95% CI: 1.10–2.03) or 60 years of age or older (aOR: 1.76, 95% CI: 1.12–2.77) were associated with default. Conclusions In multivariate analysis age was the only variable associated with default. This lack of identifiable risk factors and our qualitative findings imply that default is complex and often due to extrinsic and medication-related factors. More tolerable medications, improved side effect management, and innovative

  12. Determinants of Default from Tuberculosis Treatment among Patients with Drug-Susceptible Tuberculosis in Karachi, Pakistan: A Mixed Methods Study.

    Directory of Open Access Journals (Sweden)

    Natasha Chida

    Full Text Available Non-adherence to tuberculosis therapy can lead to drug resistance, prolonged infectiousness, and death; therefore, understanding what causes treatment default is important. Pakistan has one of the highest burdens of tuberculosis in the world, yet there have been no qualitative studies in Pakistan that have specifically examined why default occurs. We conducted a mixed methods study at a tuberculosis clinic in Karachi to understand why patients with drug-susceptible tuberculosis default from treatment, and to identify factors associated with default. Patients attending this clinic pick up medications weekly and undergo family-supported directly observed therapy.In-depth interviews were administered to 21 patients who had defaulted. We also compared patients who defaulted with those who were cured, had completed, or had failed treatment in 2013.Qualitative analyses showed the most common reasons for default were the financial burden of treatment, and medication side effects and beliefs. The influence of finances on other causes of default was also prominent, as was concern about the effect of treatment on family members. In quantitative analysis, of 2120 patients, 301 (14.2% defaulted. Univariate analysis found that male gender (OR: 1.34, 95% CI: 1.04-1.71, being 35-59 years of age (OR: 1.54, 95% CI: 1.14-2.08, or being 60 years of age or older (OR: 1.84, 95% CI: 1.17-2.88 were associated with default. After adjusting for gender, disease site, and patient category, being 35-59 years of age (aOR: 1.49, 95% CI: 1.10-2.03 or 60 years of age or older (aOR: 1.76, 95% CI: 1.12-2.77 were associated with default.In multivariate analysis age was the only variable associated with default. This lack of identifiable risk factors and our qualitative findings imply that default is complex and often due to extrinsic and medication-related factors. More tolerable medications, improved side effect management, and innovative cost-reduction measures are needed to

  13. Sale of anti-tuberculosis drugs through private pharmacies: a cross sectional study in Kerala, India.

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    Binoo Divakaran

    2011-03-01

    Full Text Available

    Background: Private health care providers are largely the first point of contact for Tuberculosis (TB patients, who either undergo treatment from private practitioners or buy medicines on their own from private pharmacies. Aims: This study assessed the availability, sale and magnitude of anti-tuberculosis drugs dispensing through private pharmacies.

    Methodology: The present cross sectional study was conducted among private pharmacies located along the national highway from Thalassery to Payyannur in the Kannur district of Kerala, India. A total of 38 private pharmacies located along the national highway were included.

    Results: The duration that anti–TB drugs had been on sale showed that 74.3% of pharmacies had started to sell these drugs only less than ten years ago. The majority (82.9% of the private pharmacies received up to 5 prescriptions for anti-TB drugs weekly. Out of the total of 35 pharmacies selling these drugs, 22 (62.9% reported an increase in their sales. Nearly 82% of those pharmacies that reported an increase in the sale of anti-TB drugs were selling these drugs for less than the past ten years.

    Conclusions: The current study shows that a large number of tuberculosis patients are still approaching private pharmacies for anti-tuberculosis drugs. This tendency has to be completely stopped and needs properly planned strategies to encourage private pharmacies to participate actively in the DOTS (Direct Observation Treatment Short course program of the Government, by providing them attractive alternative incentives

  14. Efficacy and safety of anti-tuberculosis drugs in HIV-positive patients: A prospective study

    Directory of Open Access Journals (Sweden)

    Jigar D Kapadia

    2013-01-01

    Full Text Available Objectives: To assess the efficacy and safety of anti-tuberculosis drugs in HIV-positive patients at a tertiary care teaching hospital. Materials and Methods: As a part of an ongoing study of opportunistic infections (OIs in HIV-positive patients, drug treatment in patients suffering from tuberculosis was assessed to determine its efficacy and safety. Based on prevalence data for last three years, a purposive sampling of study population was carried out in this observational, prospective, single centre study. Tuberculosis (TB was the most common OI observed. The selected patients were followed up for a period of one year to evaluate the clinical course and outcome of OIs, and the efficacy and safety of drugs used was checked. Results: Tuberculosis was observed in 89 out of 134 enrolled patients. These included 79 adults and 10 children. Males (66.2% were commonly affected. Extra pulmonary TB (73% was the most common manifestation with abdominal TB observed in 55 (61.7% patients. All patients were treated in accordance with the Revised National Tuberculosis Control Programme (RNTCP guidelines as recommended by National AIDS Control Organization (NACO, India. Outcome of TB was assessable in 70 patients. Majority (82.8% of the patients were cured, while 12 patients (17.1% died during the course of treatment. A total of 149 ADRs were observed in 67 (75.2% patients. Majority of ADRs (n = 147 were non-serious and did not warrant a change in therapy. Discoloration of urine was the most common ADR observed. Conclusion: TB is the most common opportunistic infection in HIV-positive patients with abdominal TB being the most common manifestation. RNTCP and NACO guidelines are adhered to in these patients. Anti-tuberculosis drugs are well tolerated and effective in majority of the patients.

  15. Default Meanings

    Institute of Scientific and Technical Information of China (English)

    K. M. Jaszczolt

    2006-01-01

    In this paper I present some aspects of the controversy surrounding the semantics/pragmatics boundary and offer a possible solution in the form of Default Semantics. First, I present a brief introduction to Paul Grice's approach to meaning as intentional communication. Next, I address the problem of the unit of which truth conditions should be predicated, assuming after Grice that the most successful approach to meaning has to make use of truth conditions.Further, I extend the discussion to some aspects of neo-Gricean pragmatics, most notably the issue of pragmatic processing that contributes to the truth-conditional representation and the proposed shortcuts through this processing in the form of default meanings. In the main part, I present the theory of Default Semantics ( Jaszczolt 2005a) , assess some arguments in favour of such an interactive theory of meaning that combines information from various sources, and address the issue of compositionality of meaning so conceived. In the final part, I apply the theory of Default Semantics to expressions with future-time reference in English in order to demonstrate the advantages of a framework that combines various types of information about utterance meaning in one, merged semantic representation. The main advantage turns out to be, in this domain, the unified treatment of all expressions with future-time reference.

  16. Reasons for default from treatment of chronic illnesses in a primary healthcare program in rural Tamil Nadu

    OpenAIRE

    Henry R Jennens; Rajkumar Ramasamy; Brigitte Tenni

    2013-01-01

    Chronic illnesses are an increasing cause of morbidity and mortality in rural India. Many patients default from treatment, and exploring their reasons for the same may suggest strategies to improve service accessibility and acceptability. A qualitative study was conducted of 22 patient interviews, six key informant interviews, and two patient focus group discussions for investigating the reasons for default at the KC Patty Primary Health Centre and surrounding villages in Kodaikanal Taluk, Di...

  17. 肺结核抗痨中发生类赫反应的危险因素%Risk factors for development of paradoxical response during anti-tuberculosis treatment in patients with pulmonary tuberculosis

    Institute of Scientific and Technical Information of China (English)

    胡良安; 傅玉; 罗永艾; 黄习臣

    2014-01-01

    Objective To evaluate the incidence , clinical characteristics and predicting factors for the development of paradoxical response ( PR) in patients with pulmonary tuberculosis ( TB) .Methods A retrospective cohort study was executed including 1 310 patients who were diagnosed and treated with pulmonary TB .Results PR was present in 76(5.8%) of 1 310 patients after 40±28 days following ini-tiation of treatment.Fever and cough were the most common symptoms associated with PR .24(31.6%) patients had been initially misdiag-nosed of drug-resistant TB,32(42.1%) patients had been misdiagnosed of pneumonia and 6(7.9%) patients had been misdiagnosed of lung cancer.The risk factors for PR were low body mass index (BMI), low serum albumin level, low baseline lymphocyte counts and lymphocyte count greater increase during PR development (all P<0.05).Conclusions PR is not an uncommon problem in pulmonany TB and is com-mon misdiagnosed.Low BMI, baseline hypoalbuminaemia, lymphopaenia and a greater change in lymphocyte count during PR development are associated with the development of PR .This is useful for clinical practice , especially for helping to distinguish PR from pneumonia or drug resistance .PR during the management of pulmonary TB must be paid more attention in the expected patients to develop PR .%目的:研究肺结核抗痨过程中发生类赫反应( PR)的频率、临床特点及其危险因素。方法采用病历资料的回顾性列队研究。结果符合条件的1310例肺结核患者抗痨后76例发生PR(5.8%),发生PR的时间是抗痨后(40±28)d。发热和咳嗽是PR的最常见症状。76例PR患者中误诊为耐药结核24例,肺炎32例和肺癌6例。发生PR的危险因素是:体重指数低、低白蛋白血症、初始血淋巴细胞数低和发生PR时淋巴细胞数较大增加( P均<0.05)。结论在肺结核患者抗痨中出现PR是常见现象,且易误诊;低蛋白血症、低体重指数、初始淋巴细

  18. Factors associated with tuberculosis treatment default in an endemic area of the Brazilian Amazon: a case control-study.

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    Marlucia da Silva Garrido

    Full Text Available SETTING: Treatment default is a serious problem in tuberculosis control because it implies persistence of infection source, increased mortality, increased relapse rates and facilitates the development of resistant strains. OBJECTIVE: This study analyzed tuberculosis treatment default determinants in the Amazonas State to contribute in planning appropriate control interventions. DESIGN: Observational study with a retrospective cohort using Brazilian Disease Notification System data from 2005 to 2010. A nested case control study design was used. Patients defaulting from treatment were considered as 'cases' and those completing treatment as 'controls'. In the analysis, 11,312 tuberculosis patients were included, 1,584 cases and 9,728 controls. RESULTS: Treatment default was observed to be associated to previous default (aOR 3.20; p<0.001, HIV positivity (aOR 1.62; p<0.001, alcoholism (aOR 1.51; p<0.001, low education level (aOR 1.35; p<0.001 and other co-morbidities (aOR 1.31; p = 0.05. Older patients (aOR 0.98; p = 0.001 and DOT (aOR 0,72; p<0.01 were considered as protective factor for default. CONCLUSIONS: Associated factors should be considered in addressing care and policy actions to tuberculosis control. Information on disease and treatment should be intensified and appropriate to the level of education of the population, in order to promote adherence to treatment and counter the spread of multidrug resistance to anti-TB drugs.

  19. Default probabilities and default correlations

    OpenAIRE

    Erlenmaier, Ulrich; Gersbach, Hans

    2001-01-01

    Starting from the Merton framework for firm defaults, we provide the analytics and robustness of the relationship between default correlations. We show that loans with higher default probabilities will not only have higher variances but also higher correlations between loans. As a consequence, portfolio standard deviation can increase substantially when loan default probabilities rise. This result has two important implications. First, relative prices of loans with different default probabili...

  20. Hepatitis B or hepatitis C co-infection in individuals infected with human immunodeficiency virus and effect of anti-tuberculosis drugs on liver function

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    Padmapriyadarsini C

    2006-01-01

    Full Text Available Background: Tuberculosis (TB and hepatitis are the two common co-infections in patients infected with human immunodeficiency virus (HIV. Anti-tuberculosis treatment (ATT may have an effect on the liver enzymes in these co-infected HIV patients. Aims: To determine the prevalence of Hepatitis B and C virus coinfection in HIV infected patients in Tamilnadu and assess effects of anti-tuberculosis drugs on their liver function. Settings: HIV positive subjects referred to the Tuberculosis Research Centre, Chennai Materials and Methods: All HIV infected patients referred to the Tuberculosis Research centre, from March 2000 to May 2004, were screened for Hepatitis B surface antigen (HBsAg & Hepatitis C virus (HCV antibodies by enzyme linked immunoabsorbent assay (ELISA. HIV infection was confirmed using two rapid tests and one ELISA. Patients were given either short- course anti-tuberculosis treatment or preventive therapy for tuberculosis, depending on the presence or absence of active TB, if their baseline liver functions were within normal limits. None of these patients were on antiretroviral therapy during the study period. Statistical Analysis: Paired t-test was used to find the significance between baseline and end of treatment liver enzymes levels, while logistic regression was done for assessing various associations. Results: Of the 951 HIV-infected patients, 61 patients (6.4% were HBsAg positive, 20 (2.1% had demonstrable anti HCV antibodies in their blood. Serial estimation of liver enzymes in 140 HIV patients (81 being co-infected with either HBV or HCV showed that 95% did not develop any liver toxicity while they were on anti-tuberculosis treatment or prophylaxis. Conclusions: The prevalence of hepatitis B and C coinfection was fairly high in this largely heterosexually infected population supporting the use of more careful screening for these viruses in HIV positive persons in this region. Anti-tuberculosis therapy as well as TB preventive

  1. Defaults and Donations

    DEFF Research Database (Denmark)

    Altmann, Steffen; Falk, Armin; Heidhues, Paul;

    We study how website defaults affect consumer behavior in the domain of charitable giving. In a field experiment that was conducted on a large platform for making charitable donations over the web, we exogenously vary the default options in two distinct choice dimensions. The first pertains...... to the primary donation decision, namely, how much to contribute to the charitable cause. The second relates to an "add-on" decision of how much to contribute to supporting the online platform itself. We find a strong impact of defaults on individual behavior: in each of our treatments, the modal positive...... contributions in both choice dimensions invariably correspond to the specified default amounts. Defaults, nevertheless, have no impact on aggregate donations. This is because defaults in the donation domain induce some people to donate more and others to donate less than they otherwise would have. In contrast...

  2. Reasons for default from treatment of chronic illnesses in a primary healthcare program in rural Tamil Nadu

    Directory of Open Access Journals (Sweden)

    Henry R Jennens

    2013-01-01

    Full Text Available Chronic illnesses are an increasing cause of morbidity and mortality in rural India. Many patients default from treatment, and exploring their reasons for the same may suggest strategies to improve service accessibility and acceptability. A qualitative study was conducted of 22 patient interviews, six key informant interviews, and two patient focus group discussions for investigating the reasons for default at the KC Patty Primary Health Centre and surrounding villages in Kodaikanal Taluk, Dindigul district, Tamil Nadu. The reasons included money or transport difficulties, frequent travel, feeling healthy, focus on work, fear of scolding from clinic staff, medication side effects, preference for alternative therapy, and depression. Some reasons were only divulged after an extended discussion. Support from families and village-level health workers (VLHWs were also identified as important. Recommendations include more open and patient communication between health workers and defaulting patients, in addition to recruitment of more VLHWs.

  3. Effect of anti-tuberculosis treatment in tuberculosis patients co-infected with human immunodeficiency virus in seven counties, Yunnan%云南省7县结核分枝杆菌/HIV联合感染患者抗结核疗效影响因素分析

    Institute of Scientific and Technical Information of China (English)

    许琳; 高小娇; 李玲; 王芸

    2015-01-01

    目的 分析结核分枝杆菌/HIV联合感染患者(TB/HIV)抗结核疗效的影响因素.方法 回顾性分析云南省7个中国全球基金结核病项目县2010年1月1日至2012年6月30日登记管理的445例TB/HIV的抗结核治疗结果,通过问卷收集一般人口学特征、患者来源、治疗分类等因素,并作为分组变量进行单因素x2检验.以抗结核治疗成功与否作为结局变量,采用多因素非条件logistic回归方法分析抗结核治疗效果的影响因素.结果 445例TB/HIV经标准化抗结核治疗,397例(89.21%)治疗成功,其中影响患者疗效的5个危险因素包括就诊时有>4个肺结核可疑症状(aOR=2.208)、在HIV/AIDS人群中主动筛查出的TB/HIV(aOR=5.856)、重症患者(aOR=4.607)、督导管理方式未采用全程督导(强化期督导方式aOR=4.129及全程管理方式aOR=8.090)和出现中断服药(aOR=21.517).结论 通过加强主动筛查尽早发现TB/HIV,及时提供标准化抗结核治疗和全程督导的随访管理措施,能有效改善抗结核治疗效果.%Objective To understand the potential risk factors influencing the effect of standard anti-tuberculosis (TB) treatment for TB patients co-infected with human immunodeficiency virus (HIV) and provide evidence for the improvement of anti TB therapy.Methods A retrospective study was conducted among 445 TB/HIV patients diagnosed and registered in 7 counties in Yunnan province from January 2010 to June 2012.A structured questionnaire was used to collect the patients' demographic characteristics,diagnosis and treatment information after informed consent.Chi-square test was conducted to compare successful rate of anti TB treatment among the patients with different demographic characteristics.Multivariate logistic regression analysis was conducted to identify risk factors influencing the effect of anti TB treatment.Adjusted OR>1 means the risk factor of treatment failure.P value less than 0.05 was set as significant level

  4. Charitable Giving, Emotions, and the Default Effect

    NARCIS (Netherlands)

    Noussair, Charles; Habetinova, Lenka

    2015-01-01

    We report an experiment to study the effect of defaults on charitable giving. In three different treatments, participants face varying default levels of donation. In three other treatments that are paired with the first three, they receive the same defaults, but are informed that defaults are though

  5. Default Tips

    OpenAIRE

    Kareem Haggag; Giovanni Paci

    2014-01-01

    We examine the role of defaults in high-frequency, small-scale choices using unique data on over 13 million New York City taxi rides. Using a regression discontinuity design, we show that default tip suggestions have a large impact on tip amounts. These results are supported by a secondary analysis that uses the quasi-random assignment of customers to different cars to examine default effects on a wider range of fares. Finally, we highlight a potential cost of setting defaults too high, as a ...

  6. Anti-Tuberculosis Drug Induced Hepatotoxicity among TB/HIV Co-Infected Patients at Jimma University Hospital, Ethiopia: Nested Case-Control Study

    OpenAIRE

    Alima Hassen Ali; Tefera Belachew; Alemeshet Yami; Wubeante Yenet Ayen

    2013-01-01

    BACKGROUND: This study was carried out to determine the incidence and predictors of anti-tuberculosis drug induced hepatotoxicity among TB/HIV co-infected patients at Jimma University Hospital, Ethiopia. METHODS/PRINCIPAL FINDINGS: A nested case-control study was conducted by reviewing charts of all TB/HIV co-infected patients who commenced anti-TB treatment from January 2008 to December 2011 at Jimma University Hospital. Patients who had developed hepatotoxicity after at least 5 days of stan...

  7. The rate of sputum smear-positive tuberculosis after treatment default in a high-burden setting: a retrospective cohort study.

    Directory of Open Access Journals (Sweden)

    Florian M Marx

    Full Text Available RATIONALE: High rates of recurrent tuberculosis after successful treatment have been reported from different high burden settings in Sub-Saharan Africa. However, little is known about the rate of smear-positive tuberculosis after treatment default. In particular, it is not known whether or not treatment defaulters continue to be or become again smear-positive and thus pose a potential for transmission of infection to others. OBJECTIVE: To investigate, in a high tuberculosis burden setting, the rate of re-treatment for smear-positive tuberculosis among cases defaulting from standardized treatment compared to successfully treated cases. METHODS: Retrospective cohort study among smear-positive tuberculosis cases treated between 1996 and 2008 in two urban communities in Cape Town, South Africa. Episodes of re-treatment for smear-positive tuberculosis were ascertained via probabilistic record linkage. Survival analysis and Poisson regression were used to compare the rate of smear-positive tuberculosis after treatment default to that after successful treatment. RESULTS: A total of 2,136 smear-positive tuberculosis cases were included in the study. After treatment default, the rate of re-treatment for smear-positive tuberculosis was 6.86 (95% confidence interval [CI]: 5.59-8.41 per 100 person-years compared to 2.09 (95% CI: 1.81-2.41 after cure (adjusted Hazard Ratio [aHR]: 3.97; 95% CI: 3.00-5.26. Among defaulters, the rate was inversely associated with treatment duration and sputum conversion prior to defaulting. Smear grade at start of the index treatment episode (Smear3+: aHR 1.61; 95%CI 1.11-2.33 was independently associated with smear-positive tuberculosis re-treatment, regardless of treatment outcome. CONCLUSIONS: In this high-burden setting, there is a high rate of subsequent smear-positive tuberculosis after treatment default. Treatment defaulters are therefore likely to contribute to the pool of infectious source cases in the community. Our

  8. Drug-induced Hepatotoxicity of Anti-tuberculosis Drugs and Their Serum Levels

    OpenAIRE

    Jeong, Ina; Park, Jong-Sun; Cho, Young-Jae; Yoon, Ho Il; Song, Junghan; Lee, Choon-Taek; Lee, Jae-Ho

    2015-01-01

    The correlation between serum anti-tuberculosis (TB) drug levels and the drug-induced hepatotoxicity (DIH) remains unclear. The purpose of this study was to investigate whether anti-TB DIH is associated with basal serum drug levels. Serum peak levels of isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA), and ethambutol (EMB) were analyzed in blood samples 2 hr after the administration of anti-TB medication. Anti-TB DIH and mild liver function test abnormality were diagnosed on the basis of...

  9. Anti-tuberculosis drug resistance in Sub-Saharan Africa: The case of Uganda

    OpenAIRE

    Cobelens, F.G.J.; Joloba, M.L.; Lukoye, D

    2015-01-01

    This thesis reports findings of six studies including two tuberculosis (TB) drug resistance surveys, a comparative study of HIV infection rates among patients enrolled in the survey and those under routine TB/HIV surveillance, two TB molecular epidemiological analyses and a systematic review and meta-analysis of drug-resistant TB in sub-Saharan Africa. It provides a general introduction to anti-tuberculosis drug resistance in the world and associated risk factors. Results from the drug resist...

  10. Chemical constituents and anti-tuberculosis activity of ink extracts of cuttlefish, Sepiella inermis

    Directory of Open Access Journals (Sweden)

    Muthusamy Ravichandiran

    2013-11-01

    Full Text Available Objective: To study the chemical constituents and the anti-tuberculosis activity of methanol and chloroform ink extracts of Sepiella inermis. Methods: Pulverized ink powder was extracted separately with chloroform and methanol. Chemical analysis was carried out by UV-VIS spectrophotometer, FT-IR and GC-MS. Crude extracts were tested in vitro for their activity against Mycobacterium tuberculosis using Lowenstein Jensen (L-J medium. Activity in L-J medium was assessed by mean reduction in number of colonies on extract containing bottles as compared to extract free controls. Results: GC-MS of methanol extract revealed four compounds viz. hexadecanoic acid, 9, 12- octadecadienoic acid, 9-octadecenoic acid and octadecanoic acid. The chloroform extract containing fourteen compounds. The methanol extract exhibited anti-tuberculosis activity in L-J medium at 64 µg/mL with the observed inhibition of 14 CFU. Chloroform extract displayed a weak activity against Mycobacterium tuberculosis. Conclusions: This investigation showed the methanol extract exhibited significant activity against Mycobacterium tuberculosis than chloroform extract. Since ink of sepia is available abundantly as a waste material, further studies aimed at isolation and efficacy of active substances pave the way for new anti-tuberculosis drugs.

  11. Chemical constituents and anti-tuberculosis activity of ink extracts of cuttlefish, Sepiella inermis

    Institute of Scientific and Technical Information of China (English)

    Muthusamy Ravichandiran; Selvam Thiripurasalini; Vaithilingam Ravitchandirane; Srinivasa Gopalane; Chelladurai Stella

    2013-01-01

    Objective: To study the chemical constituents and the anti-tuberculosis activity of methanol and chloroform ink extracts of Sepiella inermis.Methods:Chemical analysis was carried out by UV-VIS spectrophotometer, FT-IR and GC-MS. Crude extracts Pulverized ink powder was extracted separately with chloroform and methanol. were tested in vitro for their activity against Mycobacterium tuberculosis using Lowenstein Jensen (L-J) medium. Activity in L-J medium was assessed by mean reduction in number of colonies on extract containing bottles as compared to extract free controls.Results:octadecadienoic acid, 9-octadecenoic acid and octadecanoic acid. The chloroform extract GC-MS of methanol extract revealed four compounds viz. hexadecanoic acid, 9, 12-containing fourteen compounds. The methanol extract exhibited anti-tuberculosis activity in L-J medium at 64 µg/mL with the observed inhibition of 14 CFU. Chloroform extract displayed a weak activity against Mycobacterium tuberculosis.Conclusions:Mycobacterium tuberculosis than chloroform extract. Since ink of sepia is available abundantly as This investigation showed the methanol extract exhibited significant activity against a waste material, further studies aimed at isolation and efficacy of active substances pave the way for new anti-tuberculosis drugs.

  12. Adequacy of anti-tuberculosis drug prescriptions in Viet Nam

    DEFF Research Database (Denmark)

    Hoa, N B; Lauritsen, J M; Rieder, H L

    2012-01-01

    information on treatment regimen and the patient's weight. Treatment was successful in 89.4%. Prescriptions of tablets/vials conforming to recommendations were found for respectively 91.2%, 89.9%, 92.3% and 94.6% of the patients for RMP/isoniazid, pyrazinamide, ethambutol and streptomycin. Patients in the 25......SETTING: National Tuberculosis Program, Viet Nam, 2008. OBJECTIVES: To determine drug prescription adherence to national guidelines, to examine factors associated with an erroneous dosage of rifampin (RMP) and to evaluate the impact of an insufficient RMP dosage on treatment outcome. METHODS......: A representative sample of 30 treatment units was randomly selected. All patient treatment cards enrolled in these units were obtained, and data were double-entered and validated before calculating the adequacy of the individual drug prescriptions. RESULTS: Of 3412 tuberculosis treatment cards, 3225 (94.5%) had...

  13. New anti-tuberculosis drugs and regimens: 2015 update

    OpenAIRE

    Lia D'Ambrosio; Rosella Centis; Giovanni Sotgiu; Emanuele Pontali; Antonio Spanevello; Giovanni Battista Migliori

    2015-01-01

    Over 480 000 cases of multidrug-resistant (MDR) tuberculosis (TB) occur every year globally, 9% of them being affected by extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis. The treatment of MDR/XDR-TB is unfortunately long, toxic and expensive, and the success rate largely unsatisfactory (

  14. New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity.

    Science.gov (United States)

    Matos, Priscilla M; Mahoney, Brian; Chan, Yohan; Day, David P; Cabral, Mirela M W; Martins, Carlos H G; Santos, Raquel A; Bastos, Jairo K; Page, Philip C Bulman; Heleno, Vladimir C G

    2015-10-07

    We report herein the synthesis of six diterpene derivatives, three of which are new, generated through known organic chemistry reactions that allowed structural modification of the existing natural products kaurenoic acid (1) and copalic acid (2). The new compounds were fully characterized using high resolution mass spectrometry, infrared spectroscopy, ¹H- and (13)C-NMR experiments. We also report the evaluation of the anti-tuberculosis potential for all compounds, which showed some promising results for Micobacterium tuberculosis inhibition. Moreover, the toxicity for each of the most active compounds was also assessed.

  15. A new method for identifying causal genes of schizophrenia and anti-tuberculosis drug-induced hepatotoxicity.

    Science.gov (United States)

    Huang, Tao; Liu, Cheng-Lin; Li, Lin-Lin; Cai, Mei-Hong; Chen, Wen-Zhong; Xu, Yi-Feng; O'Reilly, Paul F; Cai, Lei; He, Lin

    2016-01-01

    Schizophrenia (SCZ) may cause tuberculosis, the treatments for which can induce anti-tuberculosis drug-induced hepatotoxicity (ATDH) and SCZ-like disorders. To date, the causal genes of both SCZ and ATDH are unknown. To identify them, we proposed a new network-based method by integrating network random walk with restart algorithm, gene set enrichment analysis, and hypergeometric test; using this method, we identified 500 common causal genes. For gene validation, we created a regularly updated online database ATDH-SCZgenes and conducted a systematic meta-analysis of the association of each gene with either disease. Till now, only GSTM1 and GSTT1 have been well studied with respect to both diseases; and a total of 23 high-quality association studies were collected for the current meta-analysis validation. Finally, the GSTM1 present genotype was confirmed to be significantly associated with both ATDH [Odds Ratio (OR): 0.71, 95% confidence interval (CI): 0.56-0.90, P = 0.005] and SCZ (OR: 0.78, 95% CI: 0.66-0.92, P = 0.004) according to the random-effect model. Furthermore, these significant results were supported by "moderate" evidence according to the Venice criteria. Our findings indicate that GSTM1 may be a causal gene of both ATDH and SCZ, although further validation pertaining to other genes, such as CYP2E1 or DRD2, is necessary. PMID:27580934

  16. New anti-tuberculosis drugs and regimens: 2015 update

    Directory of Open Access Journals (Sweden)

    Lia D'Ambrosio

    2015-05-01

    Full Text Available Over 480 000 cases of multidrug-resistant (MDR tuberculosis (TB occur every year globally, 9% of them being affected by extensively drug-resistant (XDR strains of Mycobacterium tuberculosis. The treatment of MDR/XDR-TB is unfortunately long, toxic and expensive, and the success rate largely unsatisfactory (<20% among cases with resistance patterns beyond XDR. The aim of this review is to summarise the available evidence-based updated international recommendations to manage MDR/XDR-TB, and to update the reader on the role of newly developed drugs (delamanid, bedaquiline and pretomanid as well as repurposed drugs (linezolid and meropenem clavulanate, among others used to treat these conditions within new regimens. A nonsystematic review based on historical trials results as well as on recent literature and World Health Organization (WHO guidelines has been performed, with special focus on the approach to managing MDR/XDR-TB. The new, innovative global public health interventions, recently approved by WHO and known as the “End TB Strategy”, support the vision of a TB-free world with zero death, disease and suffering due to TB. Adequate, universally accessed treatment is a pre-requisite to reach TB elimination. New shorter, cheap, safe and effective anti-TB regimens are necessary to boost TB elimination.

  17. Anti tuberculosis drug resistance in west of Iran

    Directory of Open Access Journals (Sweden)

    Parviz Mohajeri

    2014-01-01

    Full Text Available Background and Objective: Mycobacterium tuberculosis has developed resistance to antituberculosis drugs and becoming a major and alarming public health problem in worldwide. This study was aimed to determine antituberculosis drug resistance rate and to identify multidrug resistant tuberculosis (MDR-TB in West of Iran. Materials and Methods: Of 130 samples were included between December 2011 and July 2012 in the study from that 112 cases were M. tuberculosis. The proportional method was carried out according to the Clinical and Laboratory Standards Institute on Lowenstein-Jensen against isoniazid, rifampicin, streptomycin, ethambutol, pyrazinamide, para aminosalicylic acid, ethionamide, cycloserine (CYC. The microdilution method was carried out using 7H9 broth with 96 well-plates. Results: From 112 isolates, resistance was observed to isoniazid 18 (16.07%, rifampicin 16 (14.28%, streptomycin 25 (22.32%, ethambutol 15 (13.39%, pyrazinamide 27 (24.10%, para aminosalicylic acid 19 (16.96%, CYC 4 (3.57%, and ethionamide 14 (12.5% cases. 16 isolates were MDR. Conclusion: The high prevalence of MDR-TB in our study is assumed to be due to recent transmission of drug-resistant strains. Overall, the rate of drug resistance in our study was high, which is in line with findings of some high-burden countries. Hence that early case detection, rapid drug susceptibility testing, and effective anti-TB treatment is necessary.

  18. Antimicrobial peptides as novel anti-tuberculosis therapeutics.

    Science.gov (United States)

    Silva, João P; Appelberg, Rui; Gama, Francisco Miguel

    2016-01-01

    Tuberculosis (TB), a disease caused by the human pathogen Mycobacterium tuberculosis, has recently joined HIV/AIDS as the world's deadliest infectious disease, affecting around 9.6 million people worldwide in 2014. Of those, about 1.2 million died from the disease. Resistance acquisition to existing antibiotics, with the subsequent emergence of Multi-Drug Resistant mycobacteria strains, together with an increasing economic burden, has urged the development of new anti-TB drugs. In this scope, antimicrobial peptides (AMPs), which are small, cationic and amphipathic peptides that make part of the innate immune system, now arise as promising candidates for TB treatment. In this review, we analyze the potential of AMPs for this application. We address the mechanisms of action, advantages and disadvantages over conventional antibiotics and how problems associated with its use may be overcome to boost their therapeutic potential. Additionally, we address the challenges of translational development from benchside to bedside, evaluate the current development pipeline and analyze the expected global impact from a socio-economic standpoint. The quest for more efficient and more compliant anti-TB drugs, associated with the great therapeutic potential of emerging AMPs and the rising peptide market, provide an optimal environment for the emergence of AMPs as promising therapies. Still, their pharmacological properties need to be enhanced and manufacturing-associated issues need to be addressed. PMID:27235189

  19. Social Defaults: Observed Choices Become Choice Defaults

    OpenAIRE

    Young Eun Huh; Joachim Vosgerau; Morewedge, Carey K.

    2014-01-01

    Defaults effects can be created by social contexts. The observed choices of others can become social defaults, increasing their choice share. Social default effects are a novel form of social influence not due to normative or informational influence: participants were more likely to mimic observed choices when choosing in private than in public (experiment 1) and when stakes were low rather than high (experiment 2). Like other default effects, social default effects were greater for uncertain...

  20. Research Progress of the Anti-Tuberculosis Drugs%抗结核药物的研究进展

    Institute of Scientific and Technical Information of China (English)

    耿叶慧; 李子强

    2016-01-01

    目的:为进一步研发新型抗结核药物提供参考。方法通过Science Direct,Wiley,Springer Link等数据库进行文献检索,将近几年文献报道抗结核候选药物进行归纳和总结。结果最低抑菌浓度小于7μmol/L,低毒和高选择性的最有潜力的抗结核候选药物已大量出现。结论抗结核候选药物的开发思路为研发更多新型抗结核药物提供了参考。%Objective To provide a reference for further researching and developping new anti-tuberculosis drugs. Methods Through document retrieval in the databases of Science Direct, Wiley and Springer Link, etc., the literatures about new antitubercular drugs were summarized. Results The most potent anti-tuberculosis drugs with low toxicity, a high selective index and MIC values ﹤ 7 μmol/L were appeared in large numbers. Conclusion The thoughts on the development of anti-tuberculosis drugs provide perspectives on the development of new anti-tuberculosis drugs.

  1. A case study on tuberculosis treatment defaulters in Delhi: Weak health links of the community with the public sector, unsupported migrants and some misconceptions

    Directory of Open Access Journals (Sweden)

    Vinitha Jayachandran

    2014-01-01

    Full Text Available Background: Defaulters are producing the challenging, daunting category of drug resistant cases. It is important to examine and understand the patient′s notions and terms to manage them effectively. Objective: To study the reasons behind failure of adherence to treatment and to assess the health care seeking behaviour with awareness of these patients regarding the public sector provisions. Materials and Methods: In depth interviews with ten patients who had defaulted and were undergoing CAT-II treatment which included both retreatment defaulters and new defaulters, were conducted by repeated contacts in Fatehpur Beri PHC DOTS centre. Results: People refuse to seek treatment from a government health centre when they fall sick seriously as they are ready to get treated at any expense and seek private health care facility for the prompt treatment. There is a notion that free service from public sector is not as effective as private corporate hospitals. In the public sector patients defaulted because of side effects of drugs, fear of getting admitted in big tuberculosis (TB hospitals, incompatible timing, neglect, long waiting time, TB deaths in the family and lack of family support. Among migrants, lack of employers support, family support forced them to return home. Ignorance about existence of DOTS centre with free treatment was observed. Most of the patients were unaware that incomplete treatment could lead to disease. Misconceptions observed were that treatment was futile (talk in the community about drugs being useless and most of the patients were afraid of the disease and thought they could die because of it. Conclusion: Proposed measures include: Recognition of traditional medicine/complementary alternative medicine practitioners for universal access to TB diagnosis and care, Public sector should be made attractive to the middle class society through enhancement of services and user fees and empowerment initiatives for lack of social

  2. Rapid determination of anti-tuberculosis drug resistance from whole-genome sequences

    KAUST Repository

    Coll, Francesc

    2015-05-27

    Mycobacterium tuberculosis drug resistance (DR) challenges effective tuberculosis disease control. Current molecular tests examine limited numbers of mutations, and although whole genome sequencing approaches could fully characterise DR, data complexity has restricted their clinical application. A library (1,325 mutations) predictive of DR for 15 anti-tuberculosis drugs was compiled and validated for 11 of them using genomic-phenotypic data from 792 strains. A rapid online ‘TB-Profiler’ tool was developed to report DR and strain-type profiles directly from raw sequences. Using our DR mutation library, in silico diagnostic accuracy was superior to some commercial diagnostics and alternative databases. The library will facilitate sequence-based drug-susceptibility testing.

  3. Tuberculosis treatment among smear positive tuberculosis patients

    International Nuclear Information System (INIS)

    Tuberculosis is a major health problem in many parts of the world. Delay in initiation of the treatment may result in prolonged infectious state, drug resistance, relapse and death. Objectives: To determine the factors responsible for not starting tuberculosis treatment among smear positive tuberculosis patients. Study type, settings and duration: This cross sectional study was done at Pakistan Medical Research Council TB Research Center, King Edward Medical University, Lahore, from fifth March 2010 to fifth December 2010. Patients and Methods: Fifty sputum smear positive patients of tuberculosis who did not register themselves in treatment register and presumably did not initiate anti tuberculosis treatment were contacted using telephone or traced by their home addresses. Once contact was established, they were inquired about the reasons for not starting tuberculosis treatment. Results: Of 50 patients 38(76%)belonged to the lower socio economic class and 12(24%) to the lower middle class. Fourteen patients (28%) were illiterate and 23(46%) had only 8 years of education. Of the 50 cases 41(82%) were taking treatment from traditional healers and 4% did not go back to the DOTS program. Physical condition of the patient, social, domestic and religious issues also played some role in default. Conclusions: Lack of health education and poverty were the main factors responsible for non compliance from treatment. Policy message: Sputum testing sites should have a paramedic who should educate the patients about the benefits of treatment and the dangers of default or partial treatment. (author)

  4. Value of serum procalcitonin in anti-tuberculosis therapeutic effect evaluation for tuberculosis%血清降钙素原在肺结核抗结核治疗疗效评估中的价值

    Institute of Scientific and Technical Information of China (English)

    徐立; 金雪

    2013-01-01

    目的研究血清降钙素原在肺结核抗结核治疗疗效评估中的价值。方法选择2012年1月~2013年1月本科诊治的肺结核患者为研究对象(观察组),以同期未行抗结核治疗的肺结核患者为对照(对照组),比较两组患者治疗前后血清降钙素原的水平并分析不同水平降钙素原抗结核治疗疗效差异。结果观察组和对照组肺结核患者治疗前血清降钙素原差异无统计学意义,观察组患者治疗后1个月、3个月和6个月血清降钙素原显著降低( P<0.05),对照组治疗1个月、3个月和6个月血清降钙素原升高,观察组肺结核患者治疗1个月、3个月和6个月血清降钙素原均显著低于对照组(P<0.05)。治疗前降钙素原水平显著升高、轻度升高和正常患者治愈率依次降低(P<0.05)。结论肺结核患者血清降钙素原可作为其抗结核治疗疗效评估的标志物。%Objective To study the value of serum procalcitonin in anti-tuberculosis therapeutic effect evaluation for tuberculosis. Methods The patients with tuberculosis treated with anti-tuberculosis therapy in our department from January 2012 to January 2013 were selected as the observation group, while no anti-tuberculosis treatment patients with tuberculosis during the same period were selected as the control group. The level of serum procalcitonin in the two groups before and after the treatment were compared and the anti-tuberculosis therapeutic effect difference of different levels of procalcitonin were analyzed. Results There was not significant difference in the level of serum procalcitonin before the treatment between the observation group and the control group. The levels of serum procalcitonin in the observation group after the treatment of 1 month, 3 months and 6 months decreased significantly(P<0.05), while the levels of serum procalcitonin in the control group after the treatment of 1 month, 3 months and 6 months

  5. Defaulting from anti-tuberculosis treatment in a teaching hospital in Rio de Janeiro,Brazil%巴西里约热内卢一所教学医院的抗结核治疗不合作情况调查

    Institute of Scientific and Technical Information of China (English)

    C.L.G.Salles; M.B.Conde; C.Hofer; A.J.L.A.Cunha; A. L. Calcada; D.F.Menezes; L.Sa; A.L.Kritski

    2004-01-01

    背景:少数研究已经调查了医院内抗结核治疗不合作的有关因素.目的:确定巴西里约热内卢市住院病人不合作治疗的有关因素.设计:病例对照研究.方法:所有选入研究的病例均在一所教学医院开始抗结核治疗.不合作病例定义为病人中断治疗60天仍未返回治疗.经过培训的卫生保健人员采用标准表格对病例组和对照组病人进行随访调查.结果:从1997年1月1日至12月31日共登记结核病人228例.经过查阅病历,剔除了其中的39例.对其余189例病人进行家庭访视;46例被确定为病例组,117例为对照组.在家庭访视以前观察到的抗结核治疗不合作者66(28.9%)例,家庭访视后不合作治疗者46例(20.2%).多元分析结果显示,治疗不合作的最主要预测指标是:1)没有提供返回治疗卡(OR=0.099;95%CI:0.008-1.2,P=0.07),2)病人感觉医生服务不周(OR=0.16;95%CI:0.33-0.015,P=0.001),3)未测血压(OR=0.072;95%CI:0.036-0.79,P=0.024). 结论:该医院的抗结核治疗不合作相关因素表明,非常需要系统的结核病控制规划.预计实施此类规划,采取特殊方法,将有助于强化抗结核治疗的完成率和治愈率.

  6. Mortgage Default Risk

    DEFF Research Database (Denmark)

    Chauvet, Marcelle; Gabriel, Stuart; Lutz, Chandler

    2016-01-01

    We use Google search query data to develop a broad-based and real-time index of mortgage default risk. Unlike established indicators, our Mortgage Default Risk Index (MDRI) directly reflects households’concerns regarding their risk of mortgage default. The MDRI predicts housing returns, mortgage ...... delinquency indicators, and subprime credit default swaps. These results persist both in- and out-of-sample and at multiple data frequencies. Together, research findings suggest internet search queries yield valuable new insights into household mortgage default risk.......We use Google search query data to develop a broad-based and real-time index of mortgage default risk. Unlike established indicators, our Mortgage Default Risk Index (MDRI) directly reflects households’concerns regarding their risk of mortgage default. The MDRI predicts housing returns, mortgage...

  7. Reaserch progress of anti-tuberculosis drugs induced hepatotoxicity%抗结核药致肝损害的研究进展

    Institute of Scientific and Technical Information of China (English)

    周应初; 刘斌

    2011-01-01

    Drug induced hepatotoxicity (DIH), especially the anti-tuberculosis (anti-TB) drugs induced hepatotoxicity(ATDH) , impacts greatly on hunman body, and is one of the most common causes of stoping chemotherapy in tuberculosis patients. The pathogenesis of ATDH is not very clear, but the toxicity and idiosyncratic reaction have been widely studied. Its risk factors are as follows: old age, female, slow acetylation status, malnutrition, human immunodeficiency virus infection, liver diseases, excessive intake of alcohol, combination therapy, and so on. Of ATDH, the early prevention, detection, diagnosis, and treatment will be helpful to successfully complete the tuberculosis chemodierapy. Therefore , it is crucial to understand the pathogenesis and risk factors of ATDH and it is urgent to strengthen the prevention of ATDH.%tuberculosis药物性肝痛(drug induced hepatotoxicity,DIH)以抗结核药诱导的肝毒性(anti-tuberculosis drugs induced hepatotoxicity,ATDH)较常见,其对人体影响最大,是导致结核病人停止化学治疗最常见的原因之一.ATDH的发病机制尚不十分清楚,但目前以毒性反应及特异质反应研究较多,其危险因素包括高龄、女性、慢乙酰化状态、营养不良、人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染、肝疾病、过多撮入酒精,联合用药等.对ATDH的早预防、早发现、早诊断、早治疗是顺利完成结核化疗的保障.因此,了解ATDH的发病机制及危险因素显得至关重要,加强ATDH的防治是一个亟需解决的临床问题.

  8. Preparation, characterization, and in vitro cytotoxicity evaluation of a novel anti-tuberculosis reconstruction implant.

    Directory of Open Access Journals (Sweden)

    JunFeng Dong

    Full Text Available BACKGROUND: Reconstruction materials currently used in clinical for osteoarticular tuberculosis (TB are unsatisfactory due to a variety of reasons. Rifampicin (RFP is a well-known and highly effective first-line anti-tuberculosis (anti-TB drug. Poly-DL-lactide (PDLLA and nano-hydroxyapatite (nHA are two promising materials that have been used both for orthopedic reconstruction and as carriers for drug release. In this study we report the development of a novel anti-TB implant for osteoarticular TB reconstruction using a combination of RFP, PDLLA and nHA. METHODS: RFP, PDLLA and nHA were used as starting materials to produce a novel anti-TB activity implant by the solvent evaporation method. After manufacture, the implant was characterized and its biodegradation and drug release profile were tested. The in vitro cytotoxicity of the implant was also evaluated in pre-osteoblast MC3T3-E1 cells using multiple methodologies. RESULTS: A RFP/PDLLA/nHA composite was successfully synthesized using the solvent evaporation method. The composite has a loose and porous structure with evenly distributed pores. The production process was steady and no chemical reaction occurred as proved by Fourier Transform Infrared Spectroscopy (FTIR and X-Ray Diffraction (XRD. Meanwhile, the composite blocks degraded and released drug for at least 12 weeks. Evaluation of in vitro cytotoxicity in MC3T3-E1 cells verified that the synthesized composite blocks did not affect cell growth and proliferation. CONCLUSION: It is feasible to manufacture a novel bioactive anti-TB RFP/PDLLA/nHA composite by the solvent evaporation method. The composite blocks showed appropriate properties such as degradation, drug release and biosafety to MC3T3-E1 cells. In conclusion, the novel composite blocks may have great potential for clinical applications in repairing bone defects caused by osteoarticular TB.

  9. Factors associated with anti-tuberculosis medication adverse effects: a case-control study in Lima, Peru.

    Directory of Open Access Journals (Sweden)

    Kocfa Chung-Delgado

    Full Text Available BACKGROUND: Long-term exposure to anti-tuberculosis medication increases risk of adverse drug reactions and toxicity. The objective of this investigation was to determine factors associated with anti-tuberculosis adverse drug reactions in Lima, Peru, with special emphasis on MDR-TB medication, HIV infection, diabetes, age and tobacco use. METHODOLOGY AND RESULTS: A case-control study was performed using information from Peruvian TB Programme. A case was defined as having reported an anti-TB adverse drug reaction during 2005-2010 with appropriate notification on clinical records. Controls were defined as not having reported a side effect, receiving anti-TB therapy during the same time that the case had appeared. Crude, and age- and sex-adjusted models were calculated using odds ratios (OR and 95% confidence intervals (95%CI. A multivariable model was created to look for independent factors associated with side effect from anti-TB therapy. A total of 720 patients (144 cases and 576 controls were analyzed. In our multivariable model, age, especially those over 40 years (OR = 3.93; 95%CI: 1.65-9.35, overweight/obesity (OR = 2.13; 95%CI: 1.17-3.89, anemia (OR = 2.10; IC95%: 1.13-3.92, MDR-TB medication (OR = 11.1; 95%CI: 6.29-19.6, and smoking (OR = 2.00; 95%CI: 1.03-3.87 were independently associated with adverse drug reactions. CONCLUSIONS: Old age, anemia, MDR-TB medication, overweight/obesity status, and smoking history are independent risk factors associated with anti-tuberculosis adverse drug reactions. Patients with these risk factors should be monitored during the anti-TB therapy. A comprehensive clinical history and additional medical exams, including hematocrit and HIV-ELISA, might be useful to identify these patients.

  10. Impact of glutathione S-transferase M1 and T1 on anti-tuberculosis drug-induced hepatotoxicity in Chinese pediatric patients.

    Directory of Open Access Journals (Sweden)

    Fang Liu

    Full Text Available Anti-tuberculosis drug induced hepatotoxicity (ATDH is a major adverse drug reaction associated for anti-tuberculosis therapy. The glutathione S-transferases (GST plays a crucial role in the detoxification of hepatotoxic metabolites of anti-tuberculosis drugs.An association between GSTM1/GSTT1 null mutations and increased risk of ATDH has been demonstrated in adults. Given the ethnic differences and developmental changes, our study aims to investigate the potential impacts of GSTM1/GSTT1 genotypes on the development of ATDH in Han Chinese children treated with anti-tuberculosis therapy.Children receiving anti-tuberculosis therapy with or without evidence of ATDH were considered as the cases or controls, respectively. The GSTM1 and GSTT1 genotyping were performed using the polymerase chain reaction.One hundred sixty-three children (20 cases and 143 controls with a mean age of 4.7 years (range: 2 months-14.1 years were included. For the GSTM1, 14 (70.0% cases and 96 (67.1% controls had homozygous null mutations. For the GSTT1, 13 (65.0% cases and 97 (67.8% controls had homozygous null mutations. Neither the GSTM1, nor the GSTT1 polymorphism was significantly correlated with the occurrence of ATHD.Our results did not support the GSTM1 and GSTT1 polymorphisms as the predictors of ADTH in Chinese Han children treated with anti-tuberculosis drugs. An age-related association between pharmacogenetics and ATHD need to be confirmed in the further study.

  11. Design, synthesis and study of quinoxaline-2- carboxamide 1,4-DI-N-Oxide derivatives as anti-tuberculosis agents

    OpenAIRE

    Moreno-Viguri, E. (Elsa); Monge, A; Perez-Silanes, S. (Silvia)

    2013-01-01

    The experimental work presented in this memory is based on the hypothesis that quinoxalines di-N-oxide, considered to be the core of the structure, which present a carboxamide moiety on position two and aliphatic linker between this group and an aromatic system, can be proposed as potent anti-tuberculosis agents. The main purpose of this project is the synthesis of new quinoxaline di-N-oxide derivatives as anti-tuberculosis agents. The strategy consists of the design and synthesis of several ...

  12. 抗结核药物致皮疹的临床分析%Clinical Analysis of the Durg Eruptions Caused by Anti-tuberculosis Drugs

    Institute of Scientific and Technical Information of China (English)

    侍羽; 赵丽

    2015-01-01

    目的:探讨抗结核药物所致药物性皮疹的常见类型、常见的致药物以及发生过敏的预后。方法研究2013年1月~2015年4月在我院住院抗结核治疗过程中发生药物性皮疹的85例结核病患者,分析导致药物性皮疹的抗结核药物以及皮疹类型。结果有17人因各种原因未能明确致敏药物,最终明确致敏药物的为68人89例次,依次为:利福平(RFP)28例、盐酸乙胺丁醇(EMB)19例、吡嗪酰胺(PZA)15例、利福喷丁(RFT)9例、异烟肼(INH)7例、对氨基水杨酸异烟肼(DIP)4例、盐酸左氧氟沙星3例、加替沙星3例、丙硫异烟胺1例。有10例利福平过敏者未发生利福喷丁过敏,1例对利福平及利福喷丁均过敏。皮疹类型有荨麻疹型、红斑型、湿疹型、猩红热型、麻疹型、疱疹型、紫癜型等不同表现。结论抗结核药引起的过敏反应表现多种多样;发生皮疹的抗结核药物最多的是利福平,其余依次为盐酸乙胺丁醇、吡嗪酰胺、利福喷丁、异烟肼、对氨基水杨酸异烟肼,利福平与利福喷丁交叉过敏者较少;经停药抗过敏治疗预后良好。%Objective To study the the type of the medicine for al ergy induced by anti-tuberculosis drugs, and categories sequences of the sensitized drugs that induced drug eruptions, clinical features, consequences. Methods 85 patients with tuberculosis treated in the fourth hospital of Lianyungang from January 2013 to April 2015 who occur skin rashes after receiving anti-tuberculosis treatment. To study the the type of the medicine for al ergy, categories sequences of the sensitized drugs, clinical features and consequences. Results 17 patients can not be clearly induced drug hypersensitivity due to various reasons. 68 people in 89 cases ultimately defined by sensitive drugs, fol owed by rifampicin (RFP) in 28 cases, ethambutol hydrochloride (EMB) in 19 cases, pyrazinamide (PZA) in 15 cases, rifapentine (RFT) in 9 cases, 7 cases

  13. Formalizing Default Reasoning

    Institute of Scientific and Technical Information of China (English)

    1990-01-01

    Fuzzy set systems can be used to solve the problem with uncertain knowledge,and default logic can be used to solve the problem with incomplete knowledge,in some sense.In this paper,based on interval-valued fuzzy sets we introduce a method of inference which combines approximate reasoning an default ogic,and give the procedure of transforming monotonic reasoning into default reasoning.

  14. The effects of CPAP treatment on task positive and default mode networks in obstructive sleep apnea patients: an fMRI study.

    Directory of Open Access Journals (Sweden)

    Olga Prilipko

    Full Text Available INTRODUCTION: Functional magnetic resonance imaging studies enable the investigation of neural correlates underlying behavioral performance. We investigate the effect of active and sham Continuous Positive Airway Pressure (CPAP treatment on working memory function of patients with Obstructive Sleep Apnea Syndrome (OSAS considering Task Positive and Default Mode networks (TPN and DMN. METHODS: An experiment with 4 levels of visuospatial n-back task was used to investigate the pattern of cortical activation in 17 men with moderate or severe OSAS before and after 2 months of therapeutic (active or sub-therapeutic (sham CPAP treatment. RESULTS: Patients with untreated OSAS had significantly less deactivation in the temporal regions of the DMN as compared to healthy controls, but activation within TPN regions was comparatively relatively preserved. After 2 months of treatment, active and sham CPAP groups exhibited opposite trends of cerebral activation and deactivation. After treatment, the active CPAP group demonstrated an increase of cerebral activation in the TPN at all task levels and of task-related cerebral deactivation in the anterior midline and medial temporal regions of the DMN at the 3-back level, associated with a significant improvement of behavioral performance, whereas the sham CPAP group exhibited less deactivation in the temporal regions of Default Mode Network and less Task Positive Network activation associated to longer response times at the 3-back. CONCLUSION: OSAS has a significant negative impact primarily on task-related DMN deactivation, particularly in the medial temporal regions, possibly due to nocturnal hypoxemia, as well as TPN activation, particularly in the right ventral fronto-parietal network. After 2 months of active nasal CPAP treatment a positive response was noted in both TPN and DMN but without compete recovery of existing behavioral and neuronal deficits. Initiation of CPAP treatment early in the course of the

  15. 肺结核患者抗结核药物治疗不良反应%The monitoring of adverse reaction in patients with pulmonary tuberculosis treated by anti-tuberculosis drugs (a report of 247cases)

    Institute of Scientific and Technical Information of China (English)

    曾安津; 董霞

    2012-01-01

    目的 探讨肺结核在抗结核药物治疗过程中发生的不良反应.方法 对247例行抗结核药物治疗的肺结核患者出现不良反应进行分类分析.结果 不良反应主要表现为肝肾功能损害,消化道症状和中枢神经症状等;年龄超过50岁者不良反应发生率明显高于年龄低于50岁者(P<0.05).结论 肺结核患者使用抗结核药治疗应加强督导和随访,定期复查肝肾功能,及时有效处理药物不良反应.%Objective To investigate the adverse reaction of patients with pulmonary tuberculosis during the processes of anti-tu berculosis drug treatment, and provide the evidence for the development of effective prevention and treatment measures. Method The ad verse reactions of 247 patients with pulmonary tuberculosis treated with anti-tuberculosis drug therapy were classified and statistical ana lyzed. Results The main adverse reactions were liver and kidney dysfunction, gastrointestinal symptoms and nervous symptoms. The in cidence of adverse reactions in patients over the age of 50 years was significantly higher than that of patients under the age of 50 years ( P < 0. 05 ). Conclusion The treatment of anti-tuberculosis drug in patients with pulmonary tuberculosis should be strengthened supervision and follow-up, reviewing the function of liver and kidney regularly, adverse and drug reactions should be treated timely and effective, par ticularly patients over the age of 50 years.

  16. Clinical Study of Drug-resistant Pulmonary Tuberculosis Treated by Combination of Anti-Tuberculosis Chemicals and Compound Astragalus Capsule(复方黄芪胶囊)

    Institute of Scientific and Technical Information of China (English)

    姜艳; 李新; 于志勇; 尹红义; 韩玉庆

    2004-01-01

    Objective: To observe and evaluate the therapeutic effect of anti-tuberculosis (anti-TB) chemicals and Compound Astragalus Capsule (CAC) in combinedly treating drug resistant pulmonary tuberculosis (DR-TB). Methods: Ninety-two patients with DR-TB were equally randomized into the treated group (treated with combination therapy) and the control group (treated with anti-TB chemicals alone). The therapeutic course for both groups was 18 months. Therapeutic effects between the two groups were compared at the end of the therapeutic course. Sputum bacterial negative rate, focal absorption effective rate, cavity closing rate, 10-day symptom improving rate, the incidence of adverse reaction and 2-year bacteriological recurrence rate between the two groups were compared. Results: In the treated group, the sputum bacterial negative conversion rate was 84. 8%, focal absorption effective rate 91.3 %, cavity closing rate 58. 7 % and 10-day symptom improving rate 54.4%, while in the control group, the corresponding rates were 65.2%,73.9 %, 37. 0% and 26.1%, respectively. Comparison between the groups showed significant difference in all the parameters ( P<0.05, P<0.05, P<0.05 and P<0.01 ). The incidence of adverse reaction and 2year bacteriological recurrence rate in the treated group were 23.9 % and 2.6 % respectively, while those in the control group 50.0% and 16.7%, which were higher than the former group with significant difference ( P<0.01 and P<0.05, respectively). Conclusion: The therapeutic effect of combined treatment with antiTB and CAC is superior to that of treatment with anti-TB chemicals alone, and the Chinese herbal medicine showed an adverse reaction alleviating effect, which provides a new therapy for DR-TB, and therefore, it is worth spreading in clinical practice.

  17. Bioautography with TLC-MS/NMR for Rapid Discovery of Anti-tuberculosis Lead Compounds from Natural Sources

    Science.gov (United States)

    Grzelak, Edyta M.; Hwang, Changhwa; Cai, Geping; Nam, Joo-Won; Choules, Mary P.; Gao, Wei; Lankin, David C.; McAlpine, James B.; Mulugeta, Surafel G.; Napolitano, José G.; Suh, Joo-Won; Yang, Seung Hwan; Cheng, Jinhua; Lee, Hanki; Kim, Jin-Yong; Cho, Sang-Hyun; Pauli, Guido F.; Franzblau, Scott G.; Jaki, Birgit U.

    2016-01-01

    While natural products constitute an established source of lead compounds, the classical iterative bioassay-guided isolation process is both time- and labor-intensive and prone to failing to identify active minor constituents. (HP)TLC-bioautography-MS/NMR, which combines cutting-edge microbiological, chromatographic, and spectrometric technologies, was developed to accelerate anti-tuberculosis (TB) drug discovery from natural sources by acquiring structural information at a very early stage of the isolation process. Using the avirulent, bioluminescent Mtb strain mc27000 luxABCDE, three variations of bioautography were evaluated and optimized for sensitivity in detecting anti-TB agents, including established clinical agents and new leads with novel mechanisms of action. Several exemplary applications of this approach to microbial extracts demonstrate its potential as a routine method in anti-TB drug discovery from natural sources.

  18. 抗痨颗粒对耐多药结核分枝杆菌蛋白质组学的影响%Effect of Anti-tuberculosis Particles on Proteomics of Drug-resistant Mycobacterium Tuberculosis

    Institute of Scientific and Technical Information of China (English)

    李建国; 刘湘花; 汤红琴; 董修兵; 李宁宁

    2012-01-01

    目的:应用蛋白质组学的双向电泳技术,比较分析抗痨颗粒提取物作用前后耐多药结核分枝杆菌的全菌蛋白表达差异,揭示药物作用机制.方法:临床耐多药结核分枝杆菌接种在7H9添加OADC液体培养基中37℃培养6~8d,细菌密度为1×108/mL~2 × 108/mL.抗痨颗粒浸提物的最低抑菌浓度(MIC)为0.638 8 g·L-1.加到液体培养基中,作用20 h,终浓度为相当于生药0.255 6 g·mL-1.局部内环境与外部环境完全隔离下,采用双向凝胶电泳分离全菌总蛋白,得到差异表达的蛋白质点进行分析比对.结果:耐多药结核分枝杆菌用药前后,发现了8个差异斑点,确定其中2个蛋白质为:硫代硫酸硫转移酶( thiosulfate sulfurtransferase)和假定蛋白Rv0634A.结论:揭示了抗痨颗粒对耐多药结核分枝杆菌的翻译,结构组成,氨基酸代谢,氰化物和H2S的解毒以及硫和铁转移等各方面均有一定影响,从而破坏结核分枝杆菌的生活能力,从而达到抑制结核分枝杆菌的目的.%Objective; To reveal the mechanism of drug action to compare and analyze of the effect of anti-tuberculosis particles extract on multi-drug resistant-mycobacterium tuberculosis proteomics to reveal the mechanism of drug action. Method; The clinical mycobacterium tuberculosis with multidrug resistance was added in Middlebrook 7H9 OADC liquid medium at 37 ℃ for 6-8 d, when the bacterial density researched 1 × l08/mL-2 × l08/mL, the minimum inhibitory concentration ( MIC) of anti-tuberculosis particulate extracts was 0. 638 8 g · L-1 , the final concentration was equivalent to 0. 255 6 g · mL . Local environment and external environment was completely isolated, two-dimensional gel electrophoresis separation of whole cell total protein was used to analyze differentially expressed protein spots. Result; Before and after treatment by anti-tuberculosis particles extract, multidrug-resistant mycobacterium tuberculosis showed eight

  19. Mycobacterium tuberculosis whole genome sequencing and protein structure modelling provides insights into anti-tuberculosis drug resistance

    KAUST Repository

    Phelan, Jody

    2016-03-23

    Background Combating the spread of drug resistant tuberculosis is a global health priority. Whole genome association studies are being applied to identify genetic determinants of resistance to anti-tuberculosis drugs. Protein structure and interaction modelling are used to understand the functional effects of putative mutations and provide insight into the molecular mechanisms leading to resistance. Methods To investigate the potential utility of these approaches, we analysed the genomes of 144 Mycobacterium tuberculosis clinical isolates from The Special Programme for Research and Training in Tropical Diseases (TDR) collection sourced from 20 countries in four continents. A genome-wide approach was applied to 127 isolates to identify polymorphisms associated with minimum inhibitory concentrations for first-line anti-tuberculosis drugs. In addition, the effect of identified candidate mutations on protein stability and interactions was assessed quantitatively with well-established computational methods. Results The analysis revealed that mutations in the genes rpoB (rifampicin), katG (isoniazid), inhA-promoter (isoniazid), rpsL (streptomycin) and embB (ethambutol) were responsible for the majority of resistance observed. A subset of the mutations identified in rpoB and katG were predicted to affect protein stability. Further, a strong direct correlation was observed between the minimum inhibitory concentration values and the distance of the mutated residues in the three-dimensional structures of rpoB and katG to their respective drugs binding sites. Conclusions Using the TDR resource, we demonstrate the usefulness of whole genome association and convergent evolution approaches to detect known and potentially novel mutations associated with drug resistance. Further, protein structural modelling could provide a means of predicting the impact of polymorphisms on drug efficacy in the absence of phenotypic data. These approaches could ultimately lead to novel resistance

  20. Multiplex Assay of Second-Line Anti-Tuberculosis Drugs in Dried Blood Spots Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Lee, Kyunghoon; Jun, Sun Hee; Han, Minje; Song, Sang Hoon; Park, Jong Sun; Lee, Jae Ho; Park, Kyoung Un; Song, Junghan

    2016-09-01

    As dried blood spots (DBSs) have various advantages over conventional venous blood sampling, some assays for detection of one or two anti-tuberculosis (TB) drugs in DBSs have been developed. However, there are no assays currently available for the simultaneous measurement of three or more anti-TB drugs in DBSs. In this study, we developed and evaluated a multiplex method for detecting nine anti-TB drugs including streptomycin, kanamycin, clarithromycin, cycloserine, moxifloxacin, levofloxacin, para-aminosalicylic acid, prothionamide, and linezolid in DBSs by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Seventy-nine patient samples of DBS were analyzed on the UPLC-MS/MS system. All drug concentrations were determined within 4 min, and assay performance was evaluated. All drugs were clearly separated without ion suppression. Within-run and between-run precisions were 1.7-13.0% and 5.7-17.0%, respectively, at concentrations representing low and high levels for the nine drugs. Lower limits of detection and quantification were 0.06-0.6 and 0.5-5.0 μg/mL, respectively. Linearity was acceptable at five level concentrations for each drug. Correlations between drug concentrations in plasma and DBSs by using Passing-Bablock regression and Pearson's rho (ρ 0.798-0.989) were acceptable. In conclusion, we developed a multiplex assay to measure nine second-line anti-TB drugs in DBSs successfully. This assay provided convenient and rapid drug quantification and could have applications in drug monitoring during treatment. PMID:27374716

  1. Structure-based design,synthesis of novel inhibitors of Mycobacterium tuberculosis FabH as potential anti-tuberculosis agents

    Institute of Scientific and Technical Information of China (English)

    Xue Hui Zhang; Hong Yu; Wu Zhong; Li Li Wang; Song Li

    2009-01-01

    Mycobacterium tuberculosis FabH,an essential enzyme in mycolic acids biosynthetic pathway,is an attractive target for novel anti-tuberculosis agents.Structure-based design,synthesis of novel inhibitors of mrFabH was reported in this paper.A novel scaffold structure was designed,and 12 candidate compounds that displayed favorable binding with the active site were identified and synthesized.

  2. 1,4-Di-N-oxide quinoxaline-2-carboxamide: Cyclic voltammetry and relationship between electrochemical behavior, structure and anti-tuberculosis activity

    OpenAIRE

    Moreno-Viguri, E. (Elsa); Perez-Silanes, S. (Silvia); Gouravaram, S. (S.); Macharam, A. (Abinav); Ancizu, S. (Saioa); Torres, E; Aldana, I.; Monge, A; Crawford, P.W. (Philip W.)

    2011-01-01

    To gain insight into the mechanism of action, the redox properties of 37 quinoxaline-2-carboxamide 1,4-di-N-oxides with varying degrees of anti-tuberculosis activity were studied in dimethylformamide (DMF) using cyclic voltammetry and first derivative cyclic voltammetry. For all compounds studied, electrochemical reduction in DMF is consistent with the reduction of the N-oxide functionality to form a radical anion. The influence of molecular structure on reduction potential is addressed and i...

  3. Sensitivity Pattern of Second Line Anti-Tuberculosis Drugs against Clinical Isolates of Multidrug Resistant Mycobacterium Tuberculosis

    International Nuclear Information System (INIS)

    Objective:To determine the current sensitivity pattern of second line anti-tuberculosis drugs against clinical isolates of Multidrug Resistant Mycobacterium tuberculosis (MDR-TB). Study Design: A cross-sectional study. Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from November 2011 to April 2013. Methodology: Samples received during the study period were processed on BACTEC MGIT 960 system for Mycobacterium tuberculosis (MTB) culture followed by first line drugs susceptibility testing of culture proven MTB isolates. On the basis of resistance to rifampicin and isoniazid, 100 clinical isolates of MDR-TB were further subjected to susceptibility testing against amikacin (AMK), capreomycin (CAP), ofloxacin (OFL) and ethionamide (ETH) as per standard BACTEC MGIT 960 instructions. Results: Out of 100 MDR-TB isolates, 62% were from male patients and 38% from female patients. 97% were sensitive to AMK, 53% to OFL, 87% to CAP; and 87% were sensitive to ETH. Conclusion: The majority of the MDR-TB isolates showed excellent sensitivity against AMK, CAP and ETH. However, sensitivity of MDR-TB isolates against fluoroquinolones like OFL was not encouraging. (author)

  4. Anti-tuberculosis drug induced hepatotoxicity among TB/HIV co-infected patients at Jimma University Hospital, Ethiopia: nested case-control study.

    Directory of Open Access Journals (Sweden)

    Alima Hassen Ali

    Full Text Available BACKGROUND: This study was carried out to determine the incidence and predictors of anti-tuberculosis drug induced hepatotoxicity among TB/HIV co-infected patients at Jimma University Hospital, Ethiopia. METHODS/PRINCIPAL FINDINGS: A nested case-control study was conducted by reviewing charts of all TB/HIV co-infected patients who commenced anti-TB treatment from January 2008 to December 2011 at Jimma University Hospital. Patients who had developed hepatotoxicity after at least 5 days of standard doses of anti-TB drug therapy were labeled as "cases" and those without hepatotoxicity were "controls". Each case with anti-TB drug induced hepatotoxicity was compared with 3 controls selected randomly from the cohort. From a cohort of 296 TB/HIV co-infected patients 8 were excluded from the study as the causality between anti-TB drugs and hepatotoxicity was not confirmed, 33 had developed hepatotoxicity. On bivariate logistic regression analysis, body mass index (BMI <18.5 Kg/m(2 [P = 0.01; OR (95%CI: 3.6 (1.4-9.5], disseminated pulmonary TB [P = 0.00; OR (95%CI: 5.6 (2.2-14.6], CD4 count ≤50 [P = 0.016; OR (95%CI: 3.6(1.27-10.23] and WHO stage 4 [P = 0.004, OR (95%CI: 3.8 (1.68-8.77] were significantly associated with anti-TB drug induced hepatotoxicity. Predictor variables with p-value <0.05 by bivariate analysis were analyzed using multivariable logistic regression analysis and identified disseminated pulmonary TB [P = 0.001; AOR (95%CI = 5.6 (2.1-15.0] and BMI <18.5 [P = 0.014; AOR (95%CI= 3.6 (1.3-10.1] as independent predictors of anti-TB drug induced hepatotoxicity. CONCLUSIONS: The incidence of anti-TB drug induced hepatotoxicity was 11.5%. The results suggest that in the presence of disseminated pulmonary TB and/or BMI <18.5 Kg/m(2, TB/HIV co-infected patients should be closely followed for the occurrence of hepatotoxicity during the intensive phase of TB treatment to prevent morbidity and mortality.

  5. Study on the Effect of Anti Tuberculosis Drug Induced Liver Injury on the Length of Stay in Hospital%抗结核药物性肝损伤对住院天数的影响的研究

    Institute of Scientific and Technical Information of China (English)

    张宏; 覃红娟; 汪敏; 冯治宇

    2016-01-01

    Objective To evaluate the anti-tuberculosis drug-induced liver injury (DILI)impact on the the length of hospital stay.Methods According to the diagnostic criteria of drug-induced liver injury,there were 141 tuberculosis(TB)patients with DILI screened as the observation group,anther 143 TB patients without DILI screened as control group.Cinical data was recorded and studyed on the method of retrospective analysis.Results In the observation group,the median of length of hospital stay was 20.While it was 14 in the control group.The difference on the length of hospital stay between two groups was 6.Conclusion Anti-tuberculosis drug-induced liver injury will extend the length of hospital stay,resulting in a negative impact on anti-TB treatment.The DILI treatment time and the length of hospital stay have a positive corelation.%目的:探讨抗结核药物性肝损伤(drug induced liver injury,DILI)对结核病患者的住院天数影响。方法依照药物性肝损伤的诊断标准,筛选出结核药物性肝损伤病例141例作为观察组,同时筛选143例结核病作为对照组。记录两组的临床资料,从而研究抗结核药物性肝损伤对结核病患者住院天数影响。结果观察组住院天数的中位数是20,对照组住院时间的中位数是14,两者相差6。结论抗结核药物性肝损伤会延长患者的住院天数,从而对抗结核治疗产生负面的影响。

  6. Clinical significance of 2 h plasma concentrations of first-line anti-tuberculosis drugs

    DEFF Research Database (Denmark)

    Prahl, Julie B; Johansen, Isik S; Cohen, Arieh S;

    2014-01-01

    OBJECTIVES: To study 2 h plasma concentrations of the first-line tuberculosis drugs isoniazid, rifampicin, ethambutol and pyrazinamide in a cohort of patients with tuberculosis in Denmark and to determine the relationship between the concentrations and the clinical outcome. METHODS: After 6......-207 days of treatment (median 34 days) 2 h blood samples were collected from 32 patients with active tuberculosis and from three patients receiving prophylactic treatment. Plasma concentrations were determined using LC-MS/MS. Normal ranges were obtained from the literature. Clinical charts were reviewed...... failure occurred more frequently when the concentrations of isoniazid and rifampicin were both below the normal ranges (P = 0.013) and even more frequently when they were below the median 2 h drug concentrations obtained in the study (P = 0.005). CONCLUSIONS: At 2 h, plasma concentrations of isoniazid...

  7. Molecular epidemiology study of Mycobacterium tuberculosis and its susceptibility to anti-tuberculosis drugs in Indonesia

    OpenAIRE

    Lisdawati, Vivi; Puspandari, Nelly; Rif’ati, Lutfah; Soekarno, Triyani; M, Melatiwati; K, Syamsidar; Ratnasari, Lies; Izzatun, Nur; Parwati, Ida

    2015-01-01

    Background Genotyping of Mycobacterium tuberculosis helps to understand the molecular epidemiology of tuberculosis and to address evolutionary questions about the disease spread. Certain genotypes also have implications for the spread of infection and treatment. Indonesia is a very diverse country with a population with multiple ethnicities and cultures and a history of many trade and tourism routes. This study describes the first attempt to map the molecular epidemiology of TB in the Indones...

  8. Role of polymorphic bile salt export pump (BSEP, ABCB11) transporters in anti-tuberculosis drug-induced liver injury in a Chinese cohort

    OpenAIRE

    Ru Chen; Jing Wang; Shaowen Tang; Yuan Zhang; Xiaozhen Lv; Shanshan Wu; Zhirong Yang; Yinyin Xia; Dafang Chen; Siyan Zhan

    2016-01-01

    Evidence indicates that the polymorphisms in bile salt export pump (BSEP, encoded by ABCB11) may play an important role in the development of anti-tuberculosis drug-induced liver injury (ATDILI) and we aim to investigate the association between genetic variants of ABCB11 and the risk of ATDILI in a Chinese cohort. A total of 89 tuberculosis patients with ATDILI and 356 matched ATDILI -free patients constituted cases and controls. Genetic polymorphisms of ABCB11 were determined by TaqMan singl...

  9. Sunk Costs and Mortgage Default

    OpenAIRE

    Green, Richard K.; Eric Rosenblatt; Vincent Yao

    2010-01-01

    In this paper, we estimate default hazard functions that include standard variables along with borrowers sunk cost: i.e., down payment at loan origination. After testing large numbers of specifications, we find that after controlling for mark-to-market loan-to-value, initial combined loan to value remains an important predictor of default. We also find, contrary to Guiso, Sapienze and Zingales (2009), that there is not a specific point at which one observes a discontinuous default probability...

  10. Pricing options on defaultable stocks

    OpenAIRE

    Tayibov, Khayyam

    2012-01-01

    In this note, we develop stock option price approximations for a model which takes both the risk o default and the stochastic volatility into account. We also let the intensity of defaults be influenced by the volatility. We show that it might be possible to infer the risk neutral default intensity from the stock option prices. Our option price approximation has a rich implied volatility surface structure and fits the data implied volatility well. Our calibration exercise shows that an effect...

  11. Arrival of Imidazo[2,1-b]thiazole-5-carboxamides: Potent Anti-tuberculosis Agents That Target QcrB.

    Science.gov (United States)

    Moraski, Garrett C; Seeger, Natalie; Miller, Patricia A; Oliver, Allen G; Boshoff, Helena I; Cho, Sanghyun; Mulugeta, Surafel; Anderson, Jeffery R; Franzblau, Scott G; Miller, Marvin J

    2016-06-10

    Increasing interest in the potent anti-tuberculosis activity and the novel target (QcrB) of imidazo[1,2-a]pyridine-3-carboxamides encouraged extended structure-activity relationship studies of additional scaffolds. This study reports on the in vitro profiling of the imidazo[2,1-b]thiazole-5-carboxamides as a new promising class of anti-tuberculosis compounds endowed with nanomolar potency against replicating and drug-resistant Mycobacterium tuberculosis (Mtb) as well as low toxicity to VERO cells. Compounds 6, 16, and 17 had MIC values 100 μM. On-target selectivity of this series was confirmed by cross-resistance of specific QcrB mutants as well as the hypersusceptibility of a mutant with a functional gene deletion of the alternative cytochrome bd oxidase. Additionally, to demonstrate selectivity, three analogues (6, 15, 17) were broadly screened against a diverse set of eight strains of bacteria, including both Gram-positive and Gram-negative as well as six disease-causing non-tuberculosis mycobacteria. Finally, compounds 16 and 17 were found to be active in macrophages infected with Mtb. PMID:27627627

  12. Role of polymorphic bile salt export pump (BSEP, ABCB11) transporters in anti-tuberculosis drug-induced liver injury in a Chinese cohort.

    Science.gov (United States)

    Chen, Ru; Wang, Jing; Tang, Shaowen; Zhang, Yuan; Lv, Xiaozhen; Wu, Shanshan; Yang, Zhirong; Xia, Yinyin; Chen, Dafang; Zhan, Siyan

    2016-01-01

    Evidence indicates that the polymorphisms in bile salt export pump (BSEP, encoded by ABCB11) may play an important role in the development of anti-tuberculosis drug-induced liver injury (ATDILI) and we aim to investigate the association between genetic variants of ABCB11 and the risk of ATDILI in a Chinese cohort. A total of 89 tuberculosis patients with ATDILI and 356 matched ATDILI -free patients constituted cases and controls. Genetic polymorphisms of ABCB11 were determined by TaqMan single-nucleotide polymorphism (SNP) genotyping assay. Odds ratio (OR) with 95% confidence intervals (CIs) was estimated by conditional logistic regression model. There were no significant differences in genotype frequencies of ABCB11 between cases and controls. In the subgroup analysis, polymorphisms of rs2287616 were found to be associated with cholestatic/mixed pattern of liver injury under dominant and addictive model (OR = 3.84, 95% CI:1.16-12.75, P = 0.028 and OR = 2.51, 95% CI:1.12-5.62, P = 0.025, respectively), however the significance disappeared after Bonferroni correction. This study suggested that genetic variants of ABCB11 gene might contribute to anti-tuberculosis drug-induced cholestatic liver injury in Chinese patients. Studies in larger, varied populations are required to confirm these findings. PMID:27293027

  13. Sato Processes in Default Modeling

    DEFF Research Database (Denmark)

    Kokholm, Thomas; Nicolato, Elisa

    2010-01-01

    In reduced form default models, the instantaneous default intensity is the classical modeling object. Survival probabilities are then given by the Laplace transform of the cumulative hazard defined as the integrated intensity process. Instead, recent literature tends to specify the cumulative haz...

  14. Anti-tuberculosis Drugs with Novel Mechanism of Action%具有新型作用机制的抗结核药物

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Tuberculosis is one of major health problems worldwide. Approximately 1.8 mil ion people died from Tuberculosis each year which has become a global public health issue. Recently the emergence of drug resistant strains and HIV co-infection has resulted in a high incidence. As a result, there is an urgent need for us to understand the resistance mechanism and discover new anti-tuberculosis drugs. A number of new potential anti-tuberculosis drug candidates with novel modes of action have entered clinical trials in recent years. These agents are most likely to be effective against resistant strains. The paper summarized structure-activity relationships, in vitro and in vivo activity, pharmacokinetics, mechanism of action and combination regimens about several novel anti-tuberculosis drugs.%  结核病(Tuberculosis)是世界范围里的主要疾病之一,近年来,每年约有180万人死于结核病,结核病已经成为全球性的公众健康问题。近年来药物耐受以及伴有 HIV 感染的结核病发病率急剧增加,迫切需要深入了解目前抗结核药物的作用机制及耐药机制,以指导开发对持留菌和耐药菌更加有效的新型药物。近年来,一批具有全新作用机制的抗结核候选药物相继进入了临床研究,并且这些药物对耐药株表现出有效的抑制活性。文章对几类新型抗结核药物的化学结构、作用机制、构效关系、抗结核活性以及临床应用进行了综述。

  15. Reagent Precoated Targets for Rapid In-Tissue Derivatization of the Anti-Tuberculosis Drug Isoniazid Followed by MALDI Imaging Mass Spectrometry

    Science.gov (United States)

    Manier, M. Lisa; Reyzer, Michelle L.; Goh, Anne; Dartois, Veronique; Via, Laura E.; Barry, Clifton E.; Caprioli, Richard M.

    2011-08-01

    Isoniazid (INH) is an important component of front-line anti-tuberculosis therapy with good serum pharmacokinetics but unknown ability to penetrate tuberculous lesions. However, endogenous background interferences hinder our ability to directly analyze INH in tissues. Chemical derivatization has been successfully used to measure isoniazid directly from tissue samples using matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). MALDI targets were pretreated with trans-cinnamaldehyde (CA) prior to mounting tissue slices. Isoniazid present in the tissues was efficiently derivatized and the INH-CA product measured by MS/MS. Precoating of MALDI targets allows the tissues to be directly thaw-mounted and derivatized, thus simplifying the preparation. A time-course series of tissues from tuberculosis infected/INH dosed animals were assayed and the MALDI MS/MS response correlates well with the amount of INH determined to be in the tissues by high-performance liquid chromatography (HPLC)-MS/MS.

  16. LDC Borrowing with Default Risk

    OpenAIRE

    Jeffrey Sachs; Daniel Cohen

    1982-01-01

    This paper presents a theoretical model to describe the effects of default risk on international lending to LDC sovereign borrowers. The threat of defaults in international lending is shown to give rise to many characteristics of the syndicated loan market: (1) quantity rationing of loans; (2) LDC policies designed to enhance creditworthiness; (3) prevalence of short maturities on international loans; and (4) a prevalence of bank lending relative to bond-market lending

  17. Regular Disjunction-Free Default Theories

    Institute of Scientific and Technical Information of China (English)

    Xi-ShunZhao

    2004-01-01

    In this paper, the class of regular disjunction-free default theories is introduced and investigated. A transformation from regular default theories to normal default theories is established. The initial theory and the transformed theory have the same extensions when restricted to old variables. Hence, regular default theories enjoy some similar properties (e.g., existence of extensions, semi-monotonicity) as normal default theories. Then, a new algorithm for credulous reasoning of regular theories is developed. This algorithm runs in a time not more than O(1.45n), where n is the number of defaults. In case of regular prerequisite-free or semi-2CNF default theories, the credulous reasoning can be solved in polynomial time. However, credulous reasoning for semi-Horn default theories is shown to be NP-complete although it is tractable for Horn default theories. Moreover, skeptical reasoning for regular unary default theories is co-NP-complete.

  18. Regular Disjunction-Free Default Theories

    Institute of Scientific and Technical Information of China (English)

    Xi-Shun Zhao

    2004-01-01

    In this paper, the class of regular disjunction-free default theories is introduced and investigated.A transformation from regular default theories to normal default theories is established. The initial theory and the transformed theory have the same extensions when restricted to old variables. Hence, regular default theories enjoy some similar properties (e.g., existence of extensions, semi-monotonicity) as normal default theories. Then,a new algorithm for credulous reasoning of regular theories is developed. This algorithm runs in a time not more than O(1.45n), where n is the number of defaults. In case of regular prerequisite-free or semi-2CNF default theories, the credulous reasoning can be solved in polynomial time. However, credulous reasoning for semi-Horn default theories is shown to be NP-complete although it is tractable for Horn default theories. Moreover, skeptical reasoning for regular unary default theories is co-NP-complete.

  19. Risk factors for liver damage in HIV/TB patients who were treated by anti-tuberculosis%HIV/TB患者抗结核治疗强化期发生肝损伤的危险因素

    Institute of Scientific and Technical Information of China (English)

    邹俊; 刘燕芬; 吴念宁; 欧汝志; 秦英梅; 谢志满; 陆宁

    2013-01-01

    Objective To study the occurrence and the risk factors for liver damage in HIV/TB patients who were treated by anti-tuberculosis in standardized intensive phase. Method The variables from clinical and biochemical examinations of 400 cases of AIDS/TB were evaluated by Logistic regression analysis in order to determine the risk factors for liver damage in anti-tuberculosis treatment. Results The incidence of liver damage was 36.25%. With the simple factor analysis, emaciation, past history of liver injury, intravenous administration , CD4+ T-lymphocyte count, serum albumin quantitative, co-infected with HBV and eosinophils count were the risk factors. The risk of liver damage coefficients were 3.24, 2.289, 2.328 for emaciation, past history of liver injury and intravenous administration in multi-factor analysis. The serum albumin quantitative and high CD4+T-lymphocyte count can reduce the possibility of liver damage to 0.918 and 0.996. Conclusion The risk factors are associated with emaciation, past history of liver injury and intravenous administration.The high CD4+T-lymphocyte count and serum albumin quantitative can reduce the incidence of liver damage.%目的:探讨HIV/TB患者在标化抗结核治疗强化期,肝损伤的发生情况及其影响因素。方法对采用标化抗结核治疗的400例HIV/TB患者,观察强化期肝损伤发生率。选择15个可能对肝损伤产生影响的临床指标行Logistic回归分析。结果本组HIV/TB患者抗结核肝损伤的发生率为36.25%。单因素分析显示:体重减轻、既往肝损伤史、静脉途径用药、CD4+T淋巴细胞计数、白蛋白定量、合并HBV感染以及治疗后嗜酸性粒细胞增高与抗结核时肝损伤相关。多因素分析显示:既往肝损伤史、体重减轻、静脉途径用药发生肝损伤的危险系数分别为3.24、2.289、2.328;白蛋白定量高、CD4+T淋巴细胞计数升高,发生肝功能损伤的可能性降低为0.918、0.996

  20. Surveillance on first-line anti-tuberculosis drug resistance at Shanghai Port%上海口岸结核分枝杆菌一线抗结核药物耐药情况调查

    Institute of Scientific and Technical Information of China (English)

    王健; 章琪; 方筠; 叶魏; 陆晔; 张晓航; 韩晓辉; 贾哲甫; 鞠志英; 周娴

    2012-01-01

    Objective To investigate the first-line drug-resistant TB rate at Shanghai Port, and provide DST data and other evidence decision-making for directly observed treatment (DOT) as well as TB quarantine at Chinese ports. Methods From Dec. 2009 to Dec. 2011, international travel applicants who were suspected of TB patients by abnormal chest radiological exam atShanghai port were enrolled in this study. Their sputum specimen were smeared and cultured for 3 consecutive days in the early morning for mycobacterium tuberculosis isolation. MGIT 960 method wag used to detect first-line anti-tuberculosis drug resistance (streptomycin, rifampicin, isoniazid, ethambutol, pyrazinamide). Results There were 38 active tuberculosis applicants whose sputum specimen culture were positive for MTB Complex. Of which, 11 isolated strains were resistant to at least one first line anti-tuberculosis drugs. The total drug-resistant TB rale was 29.0% (11/38) which was similar to those of other five provinces in China (31.7%), and was higher than that of Hong Kong(14.4%)and global median(12.2%).There were 9 isolated strains(23.7%) which were only resistant to one anti-tuberculosis drug. Among them, 2 strains(5.3%) were resistant to streptomycin, 2 strains (5.3%) were resistant to isoniazid, five strains (13.2%) were resistant to pyrazinamide. There was 1 MDR (2.6% ) and 1 isolate (2.6% ) resistant to 3 drugs(ethambutol , isoniazid, pyrazinamide). No rifampicin and ethambutol single-resistant strain was found in this study. Conclusion The risk of drug resistance does exist in Shanghai Port currently. The overall resistance rate is above the average in other provinces in the mainland China, but higher than Hongkong and international median. DOT regimen recommended by WHO is suitable for Shanghai Pott. . It is necessary to enhance the surveillance on managing and treating these infectious TB to ensure their health and safety for international travel applicants.%目的 了解上海口岸结核分

  1. Numerical ability predicts mortgage default.

    Science.gov (United States)

    Gerardi, Kristopher; Goette, Lorenz; Meier, Stephan

    2013-07-01

    Unprecedented levels of US subprime mortgage defaults precipitated a severe global financial crisis in late 2008, plunging much of the industrialized world into a deep recession. However, the fundamental reasons for why US mortgages defaulted at such spectacular rates remain largely unknown. This paper presents empirical evidence showing that the ability to perform basic mathematical calculations is negatively associated with the propensity to default on one's mortgage. We measure several aspects of financial literacy and cognitive ability in a survey of subprime mortgage borrowers who took out loans in 2006 and 2007, and match them to objective, detailed administrative data on mortgage characteristics and payment histories. The relationship between numerical ability and mortgage default is robust to controlling for a broad set of sociodemographic variables, and is not driven by other aspects of cognitive ability. We find no support for the hypothesis that numerical ability impacts mortgage outcomes through the choice of the mortgage contract. Rather, our results suggest that individuals with limited numerical ability default on their mortgage due to behavior unrelated to the initial choice of their mortgage. PMID:23798401

  2. Testing the effect of defaults on the thermostat settings of OECD employees

    International Nuclear Information System (INIS)

    We describe a randomized controlled experiment in which the default settings on office thermostats in an OECD office building were manipulated during the winter heating season, and employees' chosen thermostat setting observed over a 6-week period. Using difference-in-differences, panel, and censored regression models (to control for maximum allowable thermostat settings), we find that a 1 °C decrease in the default caused a reduction in the chosen setting by 0.38 °C, on average. Sixty-five percent of this effect could be attributed to office occupant behavior (p-value = 0.044). The difference-in-differences models show that small decreases in the default (1°) led to a greater reduction in chosen settings than large decreases (2°). We also find that office occupants who were more apt to adjust their thermostats prior to the intervention were less susceptible to the default. We conclude that this kind of intervention can increase building-level energy efficiency, and discuss potential explanations and broader policy implications of our findings. - Highlights: • We conduct a randomized controlled trial to test if thermostat defaults affect agent behavior. • Two treatments (schedules of default settings) were tested against a control for 6 weeks at OECD. • Small changes in defaults had a greater effect on chosen settings than larger changes in defaults. • Occupants who frequently changed their thermostats in baseline were less affected by defaults. • Thermostat defaults in office environments can be manipulated to increase energy efficiency

  3. A note on neglect defaulting

    Directory of Open Access Journals (Sweden)

    Howard Margolis

    2008-04-01

    Full Text Available I introduce the notion of ``neglect defaulting,'' which labels the propensity to neglect possibilities which are ordinarily sensibly neglected. In familiar contexts we are well-tuned to recognize when to override the default. But outside the range of familiar experience --- here in the artificial context of puzzles --- these ordinarily benign defaults can make it difficult for even sophisticated subjects, such as readers of this note, to avoid responses which on reflection will be seen as obviously mistaken. A detail of particular importance is that, although subjects are easily prompted to take one step in the direction of reaching a sound response, the tendency to then neglect to consider that another step may be needed is remarkably strong. In each of the five examples the needed but usually neglected second step is quite trivial. Concluding remarks point to consequences for larger questions outside the range of familiar experience, in politics and other contexts out of scale with everyday experience.

  4. Trends of Mycobacterium bovis Isolation and First-Line Anti-tuberculosis Drug Susceptibility Profile: A Fifteen-Year Laboratory-Based Surveillance.

    Directory of Open Access Journals (Sweden)

    Miriam Bobadilla-del Valle

    2015-09-01

    Full Text Available Mycobacterium tuberculosis causes the majority of tuberculosis (TB cases in humans; however, in developing countries, human TB caused by M. bovis may be frequent but undetected. Human TB caused by M. bovis is considered a zoonosis; transmission is mainly through consumption of unpasteurized dairy products, and it is less frequently attributed to animal-to-human or human-to-human contact. We describe the trends of M. bovis isolation from human samples and first-line drug susceptibility during a 15-year period in a referral laboratory located in a tertiary care hospital in Mexico City.Data on mycobacterial isolates from human clinical samples were retrieved from the laboratory's database for the 2000-2014 period. Susceptibility to first-line drugs: rifampin, isoniazid, streptomycin (STR and ethambutol was determined. We identified 1,165 isolates, 73.7% were M. tuberculosis and 26.2%, M. bovis. Among pulmonary samples, 16.6% were M. bovis. The proportion of M. bovis isolates significantly increased from 7.8% in 2000 to 28.4% in 2014 (X(2trend, p<0.001. Primary STR resistance was higher among M. bovis compared with M. tuberculosis isolates (10.9% vs.3.4%, p<0.001. Secondary multidrug resistance (MDR rates were 38.5% and 34.4% for M. bovis and M. tuberculosis, respectively (p = 0.637. A rising trend of primary STR monoresistance was observed for both species (3.4% in 2000-2004 vs. 7.6% in 2010-2014; p = 0.02.There is a high prevalence and a rising trend of M. bovis isolates in our region. The proportion of pulmonary M. bovis isolates is higher than in previous reports. Additionally, we report high rates of primary anti-tuberculosis resistance and secondary MDR in both M. tuberculosis and M. bovis. This is one of the largest reports on drug susceptibility of M. bovis from human samples and shows a significant proportion of first-line anti-tuberculosis drug resistance.

  5. Default Distribution and Credit Market Implications

    CERN Document Server

    Mori, S; Kitsukawa, K

    2006-01-01

    We study the implied default distributions for the iTraxx-CJ tranches by means of the Principle of Maximum Entropy. The profiles are quite different from those of some popular probabilistic models. We analyze their correlation structures, the conditional default probabilities $p_{ij}$ and conditional default correlations $\\rho_{ij}$. Here the subscript ${}_{ij}$ means that the default probability and correlation are estimated under $i$ obligors are defaulted and $j$ obligors are non-defaulted among $N$ obligors. The implied default distribution, $\\rho_{n0}$ shows singular behavior, jumps high and then decreases rapidly to zero with $n$. Correspondingly $p_{n0}$ increases with $n$ and saturates to some maximum value below 1. Such a behavior implies that the credit market expects a middle scale avalanche. We also discuss the ``True'' default correlation implied by the market quotes.

  6. Firm default and aggregate fluctuations

    NARCIS (Netherlands)

    Jacobson, Tor; Linde, Jesper; Roszbach, Kasper

    2013-01-01

    This paper studies the relationship between macroeconomic fluctuations and corporate defaults while conditioning on industry affiliation and an extensive set of firm-specific factors. By using a panel data set for virtually all incorporated Swedish businesses over 1990-2009, a period which includes

  7. Constraints on Extensions of a Default Theory

    Institute of Scientific and Technical Information of China (English)

    SU Kaile

    2001-01-01

    In this paper, the representability of a family of theories as the set of extensions of a default theory is studied. First, a new necessary condition is given for the representability by means of general default theories; then a sufficient one is presented. The families of theories represented by default theories are also fully characterized. Finally, the paper gives an example of denumerable families of mutually inconsistent theories that are represented by a default theory but not by normal ones.

  8. Robustness of Distance-to-Default

    DEFF Research Database (Denmark)

    Jessen, Cathrine; Lando, David

    2015-01-01

    Distance-to-default (DD) is a measure of default risk derived from observed stock prices and book leverage using the structural credit risk model of Merton (1974). Despite the simplifying assumptions that underlie its derivation, DD has proven empirically to be a strong predictor of default. We use...

  9. First findings on the seroepidemiology of human paragonimosis at the anti-tuberculosis centre of Divo, Republic of Ivory Coast (West Africa

    Directory of Open Access Journals (Sweden)

    Aka N.A.

    2008-06-01

    Full Text Available An epidemiological study was carried out in 2004-2005 at the anti-tuberculosis centre of Divo (Ivory Coast to collect sera from patients who consulted for tuberculosis suspicion and to estimate the seroprevalence of human paragonimosis in the context of a systematic screening. No Paragonimus egg was found in the stools and/or sputa of the 167 persons investigated. In contrast, 41 sera were ascertained with antibodies against Paragonimus africanus using ELISA testing. As the optical density (OD values related to seropositive findings were found under 0.6 (the minimal OD to detect an active paragonimosis, the above antibody titres might originate from patients in chronic or in convalescent stages, or might result of cross reactions with trematodes. Concomitantly, dissection of local crabs (Callinectes marginatus demonstrated the presence of Paragonimus metacercariae in six out of 34 examined. The parasite burdens in crabs ranged from two to 35 cysts with a mean diameter of 302 μm. In Ivory Coast, the locality of Divo must be considered an at-risk zone in reason of the presence of anti-Paragonimus antibodies in several human sera and the presence of infected crabs at the local market.

  10. Development of a Nafion/MWCNT-SPCE-Based Portable Sensor for the Voltammetric Analysis of the Anti-Tuberculosis Drug Ethambutol

    Directory of Open Access Journals (Sweden)

    Rosa A. S. Couto

    2016-06-01

    Full Text Available Herein we describe the development, characterization and application of an electrochemical sensor based on the use of Nafion/MWCNT-modified screen-printed carbon electrodes (SPCEs for the voltammetric detection of the anti-tuberculosis (anti-TB drug ethambutol (ETB. The electrochemical behaviour of the drug at the surface of the developed Nafion/MWCNT-SPCEs was studied through cyclic voltammetry (CV and square wave voltammetry (SWV techniques. Electrochemical impedance spectroscopy (EIS and scanning electron microscopy (SEM were employed to characterize the modified surface of the electrodes. Results showed that, compared to both unmodified and MWCNTs-modified SPCEs, negatively charged Nafion/MWCNT-SPCEs remarkably enhanced the electrochemical sensitivity and selectivity for ETB due to the synergistic effect of the electrostatic interaction between cationic ETB molecules and negatively charged Nafion polymer and the inherent electrocatalytic properties of both MWCNTs and Nafion. Nafion/MWCNT-SPCEs provided excellent biocompatibility, good electrical conductivity, low electrochemical interferences and a high signal-to-noise ratio, providing excellent performance towards ETB quantification in microvolumes of human urine and human blood serum samples. The outcomes of this paper confirm that the Nafion/MWCNT-SPCE-based device could be a potential candidate for the development of a low-cost, yet reliable and efficient electrochemical portable sensor for the low-level detection of this antimycobacterial drug in biological samples.

  11. Determination of the activity of standard anti-tuberculosis drugs against intramacrophage Mycobacterium tuberculosis, in vitro: MGIT 960 as a viable alternative for BACTEC 460

    Directory of Open Access Journals (Sweden)

    Sarbjit Singh Jhamb

    2014-06-01

    Full Text Available BACTEC 460 has now been phased out, so the search for an alternative is imperative. We have determined the activity of standard anti-tuberculosis drugs against intramacrophage Mycobacterium tuberculosis, in vitro, by using BACTEC 460 and MGIT 960 methods. The minimum inhibitory concentrations of isoniazid, rifampicin, ethambutol and streptomycin against intracellular M. tuberculosis H37Rv were found to be 0.2, 0.8, 8.0, and 5.0 µg/mL, respectively, by both methods. These results show a significant (p < 0.001 concordance between minimum inhibitory concentrations obtained by these two different methods. MGIT 960 system uses a robust florescence quenching-based oxygen sensor, requires no radioisotope, is safe, and relatively easy to operate. Apparently, this is the first report wherein MGIT 960 has been validated for anti-tubercular susceptibility testing against intracellular M. tuberculosis H37Rv. Our preliminary data thus clearly demonstrate that the MGIT 960 method can be considered as a promising alternative to BACTEC 460 method.

  12. Development of a Nafion/MWCNT-SPCE-Based Portable Sensor for the Voltammetric Analysis of the Anti-Tuberculosis Drug Ethambutol.

    Science.gov (United States)

    Couto, Rosa A S; Quinaz, Maria Beatriz

    2016-01-01

    Herein we describe the development, characterization and application of an electrochemical sensor based on the use of Nafion/MWCNT-modified screen-printed carbon electrodes (SPCEs) for the voltammetric detection of the anti-tuberculosis (anti-TB) drug ethambutol (ETB). The electrochemical behaviour of the drug at the surface of the developed Nafion/MWCNT-SPCEs was studied through cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were employed to characterize the modified surface of the electrodes. Results showed that, compared to both unmodified and MWCNTs-modified SPCEs, negatively charged Nafion/MWCNT-SPCEs remarkably enhanced the electrochemical sensitivity and selectivity for ETB due to the synergistic effect of the electrostatic interaction between cationic ETB molecules and negatively charged Nafion polymer and the inherent electrocatalytic properties of both MWCNTs and Nafion. Nafion/MWCNT-SPCEs provided excellent biocompatibility, good electrical conductivity, low electrochemical interferences and a high signal-to-noise ratio, providing excellent performance towards ETB quantification in microvolumes of human urine and human blood serum samples. The outcomes of this paper confirm that the Nafion/MWCNT-SPCE-based device could be a potential candidate for the development of a low-cost, yet reliable and efficient electrochemical portable sensor for the low-level detection of this antimycobacterial drug in biological samples. PMID:27376291

  13. A model for dependent default with hyperbolic attenuation effect and valuation of credit default swap

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hyperbolic function is introduced to reflect the attenuation effect of one firm's default to its partner. If two firms are competitors (copartners), the default intensity of one firm will decrease (increase) abruptly when the other firm defaults. As time goes on, the impact will decrease gradually until extinct. In this model, the joint distribution and marginal distributions of default times are derived by employing the change of measure, and the fair swap premium of a credit default swap (CDS) can be valued.

  14. Highly successful treatment outcome of multidrug-resistant tuberculosis in the Netherlands, 2000-2009

    NARCIS (Netherlands)

    van Altena, R.; de Vries, G.; Haar, C. H.; de Lange, W. C. M.; Magis-Escurra, C.; van den Hof, S.; van Soolingen, D.; Boeree, M. J.; van der Werf, T. S.

    2015-01-01

    SETTING: Resistance to the two key anti-tuberculosis drugs isoniazid and rifampicin is a characteristic of multidrug-resistant tuberculosis (MDR-TB). MDR-TB is a scourge requiring toxic, prolonged treatment and is associated with poor outcomes. The Netherlands is a country with a long-standing, inte

  15. Inequality and Sovereign Default under Democracy

    Directory of Open Access Journals (Sweden)

    Yong Kyun Kim

    2013-05-01

    Full Text Available Do differences in the inequality of income affect the likelihood that democratic governments decide not to honor their foreign debt contracts? I argue that sovereign default involves an intertemporal tradeoff between an immediate consumption boost and a future tax increase. Since a poorer voter internalizes less of the future cost of default, as the median is poorer, the majority’s demand for default increases. Therefore, greater income inequality implies a higher default risk. I then present a signaling game that models strategic selection that a sovereign must go through to get to the default decision node. I show that sovereign default is most likely to actually occur when the level of income inequality is intermediate. The intuition is that sovereign default occurs when risky sovereigns successfully induce creditors to provide a loan, but the most risky ones are among those least able to do so. Empirical findings support the claim.

  16. Sato Processes in Default Modeling

    DEFF Research Database (Denmark)

    Kokholm, Thomas; Nicolato, Elisa

    In reduced form default models, the instantaneous default intensity is classically the modeling object. Survival probabilities are then given by the Laplace transform of the cumulative hazard defined as the integrated intensity process. Instead, recent literature has shown a tendency towards...... specifying the cumulative hazard process directly. Within this framework we present a new model class where cumulative hazards are described by self-similar additive processes, also known as Sato processes. Furthermore we also analyze specifications obtained via a simple deterministic time...... with those of a recently proposed class of intensity models based on Ornstein-Uhlenbeck type processes. It is shown how the time-inhomogeneous Levy models achieve comparable calibration errors with fever parameters, and with more stable parameter estimates over time. However, the calibration performances...

  17. Trends of anti-tuberculosis drug resistance pattern in new cases and previously treated cases of extrapulmonary tuberculosis cases in referral hospitals in northern India

    Directory of Open Access Journals (Sweden)

    A K Maurya

    2012-01-01

    Full Text Available Background: Drug-resistant tuberculosis is one of major current challenges to global public health. The transmission of resistant strains is increasing as a burden of multidrug-resistant tuberculosis (MDR-TB patients in extra pulmonary tuberculosis (EPTB cases in India. Aim and Objectives: The aim was to study trends of anti-tuberculosis drug resistance pattern in new cases and previously treated cases of EPTB in referral hospitals in northern India. Study Design and Setting: A prospectively observational study and referral medical institutions in northern India. Materials and Methods: All EPTB specimens were processed for Ziehl Neelsen staining, BACTEC culture and BACTEC NAP test for Mycobacterium tuberculosis complex. All M. tuberculosis complex isolates were performed for radiometric-based drug susceptibility pattern against streptomycin, isoniazid, rifampicin and ethambutol using the 1% proportion method. Results: We found that 165/756 (20.5% isolates were identified as M. tuberculosis complex by the NAP test. We observed that 39.9% were resistant to first-line antitubercular drugs. The resistance rate was higher in previously treated patients: H (30.3%, R (16.3%, E (15.7% and S (16.3%. MDR-TB was observed in 13.4%, but, in new cases, this was 11.4% and 19.1% of the previously treated patients (P<0.05. Conclusion: MDR-TB is gradually increased in EPTB cases and predominant resistance to previous treated cases of EPTB. The molecular drug sensitivity test (DST method can be an early decision for chemotherapy in MDR-TB patients. The International Standards of TB Care need to be used by the RNTCP and professional medical associations as a tool to improve TB care in the country.

  18. Polymeric emulsion and crosslink-mediated synthesis of super-stable nanoparticles as sustained-release anti-tuberculosis drug carriers.

    Science.gov (United States)

    Choonara, Yahya E; Pillay, Viness; Ndesendo, Valence M K; du Toit, Lisa C; Kumar, Pradeep; Khan, Riaz A; Murphy, Caragh S; Jarvis, Debbie-Leigh

    2011-10-15

    This study focused on evaluating four emulsion-based processing strategies for polymeric nanoparticle synthesis to explicate the mechanisms of nanoparticle formation and the influence on achieving sustained-release of two anti-tuberculosis drugs, isoniazid and rifampicin. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles were formulated with and without sorbitan mono-oleate as a stabilizer using emulsion-solvent-surfactant-evaporation (ESSE) and emulsion-solvent-evaporation (ESE) approaches. An alginate solution gelled by ionic crosslinking with calcium chloride was employed to prepare alginate hydrogel nanoparticles via reverse-emulsion-cationic-gelification (RECG) and reverse-emulsion-surfactant-cationic-gelification (RESCG) approaches. In vitro drug release analysis was performed. The size, zeta potential and morphology of the nanoparticles were analyzed. Molecular mechanics energy relationships (MMER) were employed to explore the spatial disposition of alginate and PLGA with respect to the emulsifying profile of sorbitan monooleate and to corroborate the experimental findings. Results revealed that particle size of the PLGA nanoparticles was influenced by the stabilizer concentration. Nanoparticles synthesized by the ESSE approach had smaller sizes of 240±8.7 nm and 195.5±5.4 nm for rifampicin- and isoniazid-loaded nanoparticles, respectively. This was a substantial size reduction from nanoparticles generated by the ESE approach (>1000 nm). The RESCG approach produced stable and higher nanoparticle yields with desirable size (277±1.0 nm; 289±1.2 nm), a low polydispersity index (27.1±0.3 mV; 28.5±0.5 mV) and drug entrapment efficiency of 73% and 75% for isoniazid and rifampicin, respectively. Drug release from the ESSE and RESCG synthesized nanoparticles displayed desirable release of the two anti-TB drugs with sustained zero-order kinetics over a period of 8h. MMER supported the mechanisms of nanoparticle formation with a sphericalized interlaced network

  19. A base logic for default reasoning

    Institute of Scientific and Technical Information of China (English)

    Zhou Beihai; Mao Yi

    2006-01-01

    Based on a close study of benchmark examples in default reasoning,such as Nixon Diamond,Penguin Principle,etc.,this paper provides an in depth analysis of the basic features of default reasoning.We formalize default inferences based on Modus Ponens for Default Implication,and mark the distinction between"local inferences"(to infer a conclusion from a subset of given premises)and"global inferences"(to infer a conclusion from the entire set of given premises).These conceptual analyses are captured by a formal semantics that is built upon the set-selection function technique.A minimal logic system M of default reasoning that accommodates Modus Ponens for Default Implication and suitable for local inferences is proposed,and its soundness is proved.

  20. Availability of second-line drugs and anti-tuberculosis drug susceptibility testing in China: a situational analysis

    NARCIS (Netherlands)

    G.X. He; S. van den Hof; M.W. Borgdorff; M.J. van der Werf; S.M. Cheng; Y.L. Hu; L.X. Zhang; L.X. Wang

    2010-01-01

    OBJECTIVE: To assess the availability of second-line drugs (SLDs) and the use of drug susceptibility testing (DST) results for the treatment of tuberculosis (TB) in China. DESIGN: Cross-sectional survey in 4675 health care facilities, 1960 of which have a dedicated TB clinic, in 12 provinces in Chin

  1. What HappensAfter a Greek Default

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A Greek default has already occurred in the eyes of investors, even though it technically hasn't happened yet. The market is now forcing European leaders to quickly decide how they want the rest of the sovereign debt crisis to play out. While the technical default of Greece--inevitable as it is--took around 18 months, similar defaults in other peripheral eurozone members will probably come much faster.

  2. Translating inheritance nets to default logic

    OpenAIRE

    Neumann, Ingrid

    2007-01-01

    We give a translation of inheritance nets to normal default theories. To avoid discussions about sceptical and credulous reasoning we only regard unambiguous nets but allow explicit exception links restricting the validity of direct links. Contrary to former translations every link will be translated to a "hard" fact of the corresponding default theory while the defaults only repesent the implicit assumptions made when computing the extension of the net. The translation i...

  3. Epidemiology of anti-tuberculosis drug resistance patterns and trends in tuberculosis referral hospital in Addis Ababa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Abate Dereje

    2012-08-01

    Full Text Available Abstract Background Drug-resistant TB has emerged as a major challenge facing TB prevention and control efforts. In Ethiopia, the extent/trend of drug resistance TB is not well known. The aim of this study was to determine the pattern and trend of resistance to first line anti-TB drugs among culture positive retreatment cases at St.Peter’s TB Specialized Hospital. Findings A hospital based retrospective study was used to assess the pattern of anti-TB drug resistance among previously treated TB patients referred to St.Peter’s TB Specialized Hospital from January 2004-December 2008 Gregorian calendar(GC for better diagnosis and treatment. Among 376 culture positive for M. tuberculosis one hundred and two (27.1% were susceptible to all of the four first line anti-TB drugs -Isoniazid (INH, Rifampicin (RIF, Ethambutol (ETB & Streptomycin (STM. While 274 (72.9% were resistant to at least one drug. Any resistance to STM (67.3% was found to be the most common and the prevalence of MDR-TB was 174 (46.3%. Trend in resistance rate among re-treatment cases from 2004 to 2008 showed a significant increase for any drug as well as for INH, RIF, and MDR resistance (P Conclusions There has been an increasing trend in drug resistance in recent years, particularly in retreatment cases. Therefore, establishing advanced diagnostic facilities for early detection of MDR-TB and expanding second line treatment center to treat MDR-TB patients and to prevent its transmission is recommended.

  4. Development of a prediction system for anti-tuberculosis drug-induced liver injury in Japanese patients

    Science.gov (United States)

    Mushiroda, Taisei; Yanai, Hideki; Yoshiyama, Takashi; Sasaki, Yuka; Okumura, Masao; Ogata, Hideo; Tokunaga, Katsushi

    2016-01-01

    Drug-induced liver injury (DILI) is a common adverse drug reaction in patients receiving antituberculosis (anti-TB) treatment. Among the anti-TB agents, isoniazid (INH) is the primary drug that causes hepatotoxicity in TB patients with DILI. Previous reports in several populations have consistently demonstrated an association between polymorphisms in the N-acetyltransferase 2 (NAT2) gene, which is responsible for INH hepatic metabolism, and a risk of DILI in TB patients. In this study, the genetic and baseline clinical data from 366 Japanese patients with TB (73 patients with DILI and 293 without DILI) were used to develop a system to predict DILI risk due to anti-TB agents. The distribution of the NAT2 acetylator status among the TB patients with DILI was 31 (42.5%), 29 (39.7%), and 13 (17.8%) for rapid, intermediate, and slow acetylators, respectively. A significant association was observed between NAT2 slow acetylators and DILI risk (odds ratio 4.32, 95% confidence interval 1.93–9.66, P value=5.56×10−4). A logistic regression model based on age and NAT2 genotype revealed that the area under the curve for the receiver-operating characteristic curve was 0.717. The findings demonstrated that slow NAT2 acetylator status is a significant predictor of the risk of DILI by anti-TB agents, and a personalized anti-TB treatment approach may aid in making treatment decisions and reducing the incidence of DILI. PMID:27340556

  5. Development of a prediction system for anti-tuberculosis drug-induced liver injury in Japanese patients.

    Science.gov (United States)

    Mushiroda, Taisei; Yanai, Hideki; Yoshiyama, Takashi; Sasaki, Yuka; Okumura, Masao; Ogata, Hideo; Tokunaga, Katsushi

    2016-01-01

    Drug-induced liver injury (DILI) is a common adverse drug reaction in patients receiving antituberculosis (anti-TB) treatment. Among the anti-TB agents, isoniazid (INH) is the primary drug that causes hepatotoxicity in TB patients with DILI. Previous reports in several populations have consistently demonstrated an association between polymorphisms in the N-acetyltransferase 2 (NAT2) gene, which is responsible for INH hepatic metabolism, and a risk of DILI in TB patients. In this study, the genetic and baseline clinical data from 366 Japanese patients with TB (73 patients with DILI and 293 without DILI) were used to develop a system to predict DILI risk due to anti-TB agents. The distribution of the NAT2 acetylator status among the TB patients with DILI was 31 (42.5%), 29 (39.7%), and 13 (17.8%) for rapid, intermediate, and slow acetylators, respectively. A significant association was observed between NAT2 slow acetylators and DILI risk (odds ratio 4.32, 95% confidence interval 1.93-9.66, P value=5.56×10(-4)). A logistic regression model based on age and NAT2 genotype revealed that the area under the curve for the receiver-operating characteristic curve was 0.717. The findings demonstrated that slow NAT2 acetylator status is a significant predictor of the risk of DILI by anti-TB agents, and a personalized anti-TB treatment approach may aid in making treatment decisions and reducing the incidence of DILI. PMID:27340556

  6. Tuberculosis in Sudan: a study of Mycobacterium tuberculosis strain genotype and susceptibility to anti-tuberculosis drugs

    Directory of Open Access Journals (Sweden)

    Sharaf Eldin Ghada S

    2011-08-01

    Full Text Available Abstract Background Sudan is a large country with a diverse population and history of civil conflict. Poverty levels are high with a gross national income per capita of less than two thousand dollars. The country has a high burden of tuberculosis (TB with an estimated 50,000 incident cases during 2009, when the estimated prevalence was 209 cases per 100,000 of the population. Few studies have been undertaken on TB in Sudan and the prevalence of drug resistant disease is not known. Methods In this study Mycobacterium tuberculosis isolates from 235 patients attending three treatment centers in Sudan were screened for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin by the proportion method on Lowenstein Jensen media. 232 isolates were also genotyped by spoligotyping. Demographic details of patients were recorded using a structured questionnaire. Statistical analyses were conducted to examine the associations between drug resistance with risk ratios computed for a set of risk factors (gender, age, case status - new or relapse, geographic origin of the patient, spoligotype, number of people per room, marital status and type of housing. Results Multi drug-resistant tuberculosis (MDR-TB, being resistance to at least rifampicin and isoniazid, was found in 5% (95% CI: 2,8 of new cases and 24% (95% CI: 14,34 of previously treated patients. Drug resistance was associated with previous treatment with risk ratios of 3.51 (95% CI: 2.69-4.60; p Conclusions We conclude that emergence of drug resistant tuberculosis has the potential to be a serious public health problem in Sudan and that strengthened tuberculosis control and improved monitoring of therapy is needed. Further surveillance is required to fully ascertain the extent of the problem.

  7. 24 CFR 886.314 - Financial default.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Financial default. 886.314 Section 886.314 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... Program for the Disposition of HUD-Owned Projects § 886.314 Financial default. In the event of a...

  8. Application of Fluorescent Protein Expressing Strains to Evaluation of Anti-Tuberculosis Therapeutic Efficacy In Vitro and In Vivo.

    Science.gov (United States)

    Kong, Ying; Yang, Dong; Cirillo, Suat L G; Li, Shaoji; Akin, Ali; Francis, Kevin P; Maloney, Taylor; Cirillo, Jeffrey D

    2016-01-01

    The slow growth of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), hinders development of new diagnostics, therapeutics and vaccines. Using non-invasive real-time imaging technologies to monitor the disease process in live animals would facilitate TB research in all areas. We developed fluorescent protein (FP) expressing Mycobacterium bovis BCG strains for in vivo imaging, which can be used to track bacterial location, and to quantify bacterial load in live animals. We selected an optimal FP for in vivo imaging, by first cloning six FPs: tdTomato, mCherry, mPlum, mKate, Katushka and mKeima, into mycobacteria under either a mycobacterial Hsp60 or L5 promoter, and compared their fluorescent signals in vitro and in vivo. Fluorescence from each FP-expressing strain was measured with a multimode reader using the optimal excitation and emission wavelengths for the FP. After normalizing bacterial numbers with optical density, the strain expressing L5-tdTomato displayed the highest fluorescence. We used the tdTomato-labeled M. bovis BCG to obtain real-time images of pulmonary infections in living mice and rapidly determined the number of bacteria present. Further comparison between L5-tdTomato and Hsp60-tdTomato revealed that L5-tdTomato carried four-fold more tdTomato gene copies than Hsp60-tdTomato, which eventually led to higher protein expression of tdTomato. Evaluating anti-TB efficacy of rifampicin and isoniazid therapy in vitro and in vivo using the L5-tdTomato strain demonstrated that this strain can be used to identify anti-TB therapeutic efficacy as quickly as 24 h post-treatment. These M. bovis BCG reporter strains represent a valuable new tool for evaluation of therapeutics, vaccines and virulence. PMID:26934495

  9. Application of Fluorescent Protein Expressing Strains to Evaluation of Anti-Tuberculosis Therapeutic Efficacy In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Ying Kong

    Full Text Available The slow growth of Mycobacterium tuberculosis (Mtb, the causative agent of tuberculosis (TB, hinders development of new diagnostics, therapeutics and vaccines. Using non-invasive real-time imaging technologies to monitor the disease process in live animals would facilitate TB research in all areas. We developed fluorescent protein (FP expressing Mycobacterium bovis BCG strains for in vivo imaging, which can be used to track bacterial location, and to quantify bacterial load in live animals. We selected an optimal FP for in vivo imaging, by first cloning six FPs: tdTomato, mCherry, mPlum, mKate, Katushka and mKeima, into mycobacteria under either a mycobacterial Hsp60 or L5 promoter, and compared their fluorescent signals in vitro and in vivo. Fluorescence from each FP-expressing strain was measured with a multimode reader using the optimal excitation and emission wavelengths for the FP. After normalizing bacterial numbers with optical density, the strain expressing L5-tdTomato displayed the highest fluorescence. We used the tdTomato-labeled M. bovis BCG to obtain real-time images of pulmonary infections in living mice and rapidly determined the number of bacteria present. Further comparison between L5-tdTomato and Hsp60-tdTomato revealed that L5-tdTomato carried four-fold more tdTomato gene copies than Hsp60-tdTomato, which eventually led to higher protein expression of tdTomato. Evaluating anti-TB efficacy of rifampicin and isoniazid therapy in vitro and in vivo using the L5-tdTomato strain demonstrated that this strain can be used to identify anti-TB therapeutic efficacy as quickly as 24 h post-treatment. These M. bovis BCG reporter strains represent a valuable new tool for evaluation of therapeutics, vaccines and virulence.

  10. Clinico-pathological profile and treatment outcome in smear negative pulmonary tuberculosis patients at a teaching hospital

    International Nuclear Information System (INIS)

    Tuberculosis remains the single highest contributor to the world's morbidity and mortality. Early diagnosis and prompt treatment is essential to prevent its transmission. To see the treatment response of anti tuberculosis drugs in smear negative patients and study the predictors of culture positive among smear negative tuberculosis patients. Ninety four sputum smear negative patients clinically and radiologically suggestive of tuberculosis were selected. These patients were put on anti tuberculosis drugs without waiting for their culture results. They were then followed for 8 months to see their treatment outcome. A total of 94 smear negative patients were selected and given anti tuberculosis treatment. Of these 37(39%) were culture positive and 57(61%) were culture negative. Of the 37 culture positive patients 36(97%) showed clinical or radiological improvement as compared to 46(81%) out of 57 in culture negative cases. Symptoms of cough with sputum production was significantly associated with culture positivity. On x-ray chest moderate lesion with diffuse infiltration was more common finding in 64% while extensive and cavitatory lesion was seen in 24% of all cases. Association of extensive and cavitatory lesion were seen in culture positive group. Response to anti tuberculosis drugs in sputum smear negative tubercolosis suspects was found to be effective in majority of the patients. Cough, sputum and extensive cavitatory lung lesion were the predictors of culture positive cases. There is need to train physicians on the use of anti tuberculosis therapy in smear negative suspected pulmonary tuberculosis cases, especially if they have productive cough and cavitatory lung lesions. (author)

  11. The epidemic status of drug-resistant tuberculosis and research progress of anti-tuberculosis drugs%耐药结核病流行现状及抗结核药物研究进展

    Institute of Scientific and Technical Information of China (English)

    许寅; 孟现民; 张永信

    2013-01-01

    China is one of the 22 countries with serious tuberculosis epidemic in the whole world and is also one of the 27 countries with the serious multidrug-resistant tuberculosis (MDR-TB). MDR-TB has become the tough problem of public health in many countries. It is an important link to study and develop the new anti-tuberculosis drugs to prevent and control tuberculosis and to improve their efficacy. This article introduces the tuberculosis, especially epidemic status of drug-resistant tuberculosis and research progress of anti-tuberculosis drugs.%  我国是全球22个结核病流行严重的国家之一,同时也是全球27个耐多药结核病流行严重的国家之一。耐多药结核病在许多国家已成为主要公共卫生问题,而研发新型抗结核药物是有效遏制结核病流行和提高结核病防治效果的重要环节之一。本文介绍结核病、尤其是耐多药结核病的流行现状以及抗结核药物研发的最新进展。

  12. Diagnosis and treatment of spinal tuberculosis after liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Peng-Cheng Gu; Rong-Huan Wu; Xiang-Jin Lin

    2009-01-01

    BACKGROUND: Spinal tuberculosis is a common disease in orthopedic clinical practice; however, it is seldom reported after organ transplantation. The aim of this study was to investigate the diagnosis and treatment of spinal tuberculosis after organ transplantation. METHOD: Two cases were diagnosed as spinal tuberculosis after liver transplantation and were treated with socarboxazide, rifampicin, streptomycin and ethambutol for more than one year. RESULTS: After treatment with anti-tuberculosis drugs for several months, the symptoms of both patients clearly improved. Back pain disappeared, and erythrocyte sedimentation and body temperature returned to normal. CONCLUSIONS: We should highly suspect spinal tuberculosis if notalgia and night sweats are present after organ transplantation. Anti-tuberculosis therapy is an effective treatment for spinal tuberculosis after organ transplantation.

  13. Hedging contingent claims on defaultable assets

    Science.gov (United States)

    Beumee, Johan G. B.

    2001-02-01

    Following the JLT model (Jarrow, Lando and Turnbull), this paper represents a defaultable asset as a continuous stochastic process plus a Poisson jump modelling the bankruptcy event. It is shown that if the recovery condition is known beforehand, a contingent claim can be hedged by a position in the defaultable asset and a risk-free instrument. In addition, the claim must satisfy a jump-diffusion equation and a risk-neutral representation is obtained using this equation. Examples include the price of a risky zero-coupon bond with a fixed recovery value and the prices of risky Call/Put options on corporate instruments (instrument terminates upon default).

  14. 40 CFR 305.24 - Default order.

    Science.gov (United States)

    2010-07-01

    ... COMMUNITY RIGHT-TO-KNOW PROGRAMS COMPREHENSIVE ENVIRONMENTAL RESPONSE, COMPENSATION, AND LIABILITY ACT.... Default by the Requestor may result in the dismissal of the Request for a Hearing with prejudice....

  15. 40 CFR 22.17 - Default.

    Science.gov (United States)

    2010-07-01

    ... the action, and shall result in the dismissal of the complaint with prejudice. (b) Motion for default... the requested relief is clearly inconsistent with the record of the proceeding or the Act. For...

  16. Adaboost Ensemble Classifiers for Corporate Default Prediction

    Directory of Open Access Journals (Sweden)

    Suresh Ramakrishnan

    2015-01-01

    Full Text Available This study aims to show a substitute technique to corporate default prediction. Data mining techniques have been extensively applied for this task, due to its ability to notice non-linear relationships and show a good performance in presence of noisy information, as it usually happens in corporate default prediction problems. In spite of several progressive methods that have widely been proposed, this area of research is not out dated and still needs further examination. In this study, the performance of multiple classifier systems is assessed in terms of their capability to appropriately classify default and non-default Malaysian firms listed in Bursa Malaysia. Multi-stage combination classifiers provided significant improvements over the single classifiers. In addition, Adaboost shows improvement in performance over the single classifiers.

  17. 34 CFR 668.217 - Default prevention plans.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Default prevention plans. 668.217 Section 668.217... Default prevention plans. (a) First year. (1) If your cohort default rate is equal to or greater than 30 percent you must establish a default prevention task force that prepares a plan to— (i) Identify...

  18. GDP-linked bonds and sovereign default

    OpenAIRE

    Barr, David; Bush, Oliver; Pienkowski, Alex

    2014-01-01

    Using a calibrated model of endogenous sovereign default, we explore how GDP-linked bonds can raise the maximum sustainable debt level of a government, and substantially reduce the incidence of default. The model explores both the costs (in particular the GDP risk premium) and the benefits of issuing GDP-linked bonds. It concludes that significant welfare gains can be achieved by indexing debt to GDP.

  19. Adaboost Ensemble Classifiers for Corporate Default Prediction

    OpenAIRE

    Suresh Ramakrishnan; Maryam Mirzaei; Mahmoud Bekri

    2015-01-01

    This study aims to show a substitute technique to corporate default prediction. Data mining techniques have been extensively applied for this task, due to its ability to notice non-linear relationships and show a good performance in presence of noisy information, as it usually happens in corporate default prediction problems. In spite of several progressive methods that have widely been proposed, this area of research is not out dated and still needs further examination. In this study, the pe...

  20. On the Cultural Default in Translation Practice

    Institute of Scientific and Technical Information of China (English)

    孔妍

    2011-01-01

    With the increasingly frequent communication among the cross-cultures,translation as a quite important subjecr,carries an extraordinary meaning.However,the existence fo the cultural default brought a great deal of obstacles and inconvenience to the communication of the cross-culture.In order to eliminate these obstacles during the process of the communication,this paper will firstly make some deep researches,further explorations and exact conclusions on the cultural default.

  1. Country Default Probabilities: Assessing and Backtesting

    OpenAIRE

    Vogl, Konstantin; Maltritz, Dominik; Huschens, Stefan; Karmann, Alexander

    2006-01-01

    We address the problem how to estimate default probabilities for sovereign countries based on market data of traded debt. A structural Merton-type model is applied to a sample of emerging market and transition countries. In this context, only few and heterogeneous default probabilities are derived, which is problematic for backtesting. To deal with this problem, we construct likelihood ratio test statistics and quick backtesting procedures.

  2. Default Risk and Risk Averse International Investors

    OpenAIRE

    Lizarazo, Sandra

    2010-01-01

    This paper develops a quantitative model of debt and default for small open economies that interact with risk averse international investors. The model developed here extends the recent work on the analysis of endogenous default risk to the case in which international investors are risk averse agents with decreasing absolute risk aversion (DARA). By incorporating risk averse investors who trade with a single emerging economy, the present model o ers two main improvements over the standard cas...

  3. The Treatment Strategies and Inspiration of Student loans Default in America%美国国家助学贷款拖欠处理策略及其启示

    Institute of Scientific and Technical Information of China (English)

    许文杰; 金天星; 许峥

    2015-01-01

    Student loans are important to alleviate students'school pressure ,and ensure excellent students to complete their studies .Student loans default ,especially severe default can lead to a difficulty in the turnover of load ,which will restrict the implementation of lending policies fundamentally .Our country has appeared this kind of phenomenon because of the difficult management of liquidity after graduation , the difficulty of finding jobs leading to the employment instability ,and a small number of students with poor credit consciousness . USA government has increased loan recovery efforts , developed flexible schemes of owing on the loan to increase penalties ,and strengthened the advisory guidance practices , which will give inspiration and reference for the disposal of student loans default in our country .%助学贷款对于缓解学生的就学压力,保证优秀学子完成学业至关重要。助学贷款拖欠,特别是严重拖欠会使贷金周转困难,从根本上制约着贷款制度的正常运行和持续健康发展。毕业后流动性大所带来的管理难度大、找工作难度提升所带来的择业不稳定、信用意识不强是致使我国助学贷款拖欠问题越来越严重的主要原因。美国政府加大贷款回收的力度、制定灵活多样的还贷方案、加大惩罚力度、强化咨询指导等做法对我国处置学生助学贷款拖欠问题具有启示和借鉴意义。

  4. Systematic and Idiosyncratic Default Risk in Synthetic Credit Markets

    DEFF Research Database (Denmark)

    Feldhütter, Peter; Nielsen, Mads Stenbo

    2012-01-01

    We present a new estimation approach that allows us to extract from spreads in synthetic credit markets the contribution of systematic and idiosyncratic default risk to total default risk. Using an extensive dataset of 90,600 credit default swap and collateralized debt obligation (CDO) tranche...... spreads on the North American Investment Grade CDX index, we conduct an empirical analysis of an intensity-based model for correlated defaults. Our results show that systematic default risk is an explosive process with low volatility, while idiosyncratic default risk is more volatile but less explosive...

  5. Characterization of an Auto-Compatible Default Theory

    Institute of Scientific and Technical Information of China (English)

    XU DaoYun(许道云); DING DeCheng(丁德成); ZHANG MingYi(张明义)

    2003-01-01

    In this paper, an equivalence condition for deciding whether a default theory isan auto-compatible default one is presented. Under the condition, the existence of extension of anauto-compatible default theory is a natural result. By introducing a well-ordering over the set D ofdefault rules, the extensions of an auto-compatible default theory (D, W) can be computed directly.The condition represents clearly the characterization of an auto-compatible default theory, andsome properties about auto-compatible default theory, such as semi-monotonicity, become naturalcorollaries. Based on the characterization, the revision of default beliefs is discussed to ensure theexistence of extension of the default theory, and the method is applied to investigate stable modelsof a general logic program.

  6. Moody's Correlated Binomial Default Distributions for Inhomogeneous Portfolios

    CERN Document Server

    Mori, S; Kitsukawa, K

    2006-01-01

    This paper generalizes Moody's correlated binomial default distribution for homogeneous credit portfolio, which is introduced by Witt, to the case of inhomogeneous portfolios. As inhomogeneous portfolios, we consider two cases. In the first case, we treat a portfolio whose assets have uniform default correlation and non-uniform default probabilities. We obtain the default probability distribution and study the effect of the inhomogeneity on it. The second case corresponds to a portfolio with inhomogeneous default correlation. Assets are categorized in several different sectors and the inter-sector and intra-sector correlations are not the same. We construct the joint default probabilities and obtain the default probability distribution. We show that as the number of assets in each sector decreases, inter-sector correlation becomes more important than the intra-sector one. We study the maximum values of the inter-sector default correlation. In the modeling of portfolio credit risk, it is possible to incorporat...

  7. Determinants of automobile loan default and prepayment

    OpenAIRE

    Sumit Agarwal; Ambrose, Brent W.; Souphala Chomsisengphet

    2008-01-01

    The authors examine whether a borrower’s choice of automobile reveals information about future loan performance. They find that loans on most luxury automobiles have a higher probability of prepayment, while loans on most economy automobiles have a lower probability of default, even when holding traditional risk factors, such as income and credit score, constant.

  8. Embedding Description Logic Programs into Default Logic

    CERN Document Server

    Wang, Yisong; Yuan, Li Yan; Shen, Yi-Dong; Eiter, Thomas

    2011-01-01

    Description logic programs (dl-programs) under the answer set semantics formulated by Eiter {\\em et al.} have been considered as a prominent formalism for integrating rules and ontology knowledge bases. A question of interest has been whether dl-programs can be captured in a general formalism of nonmonotonic logic. In this paper, we study the possibility of embedding dl-programs into default logic. We show that dl-programs under the strong and weak answer set semantics can be embedded in default logic by combining two translations, one of which eliminates the constraint operator from nonmonotonic dl-atoms and the other translates a dl-program into a default theory. For dl-programs without nonmonotonic dl-atoms but with the negation-as-failure operator, our embedding is polynomial, faithful, and modular. In addition, our default logic encoding can be extended in a simple way to capture recently proposed weakly well-supported answer set semantics, for arbitrary dl-programs. These results reinforce the argument ...

  9. Collective strategic defaults: Bailouts and repayment incentives

    NARCIS (Netherlands)

    R. Vlahu

    2008-01-01

    This paper shows that under a global games approach banks may be subject to risk of failure even when fundamentals are strong due to a coordination problem among debtors. As a result of collective strategic default a financially sound firm may claim inability to repay if it expects a sufficient numb

  10. Fixed-Parameter Tractability of Disjunction-Free Default Reasoning

    Institute of Scientific and Technical Information of China (English)

    ZHAO XiShun(赵希顺); DING DeCheng(丁德成)

    2003-01-01

    In this paper, the parameter which is the source of the complexity of disjunctionfree default reasoning is determined. It is shown that when the value of this parameter is fixed, the disjunction-free default reasoning can be solved in time bounded by a polynomial whose degree does not depend on the parameter. Consequently, disjunction-free default reasoning is fixed parameter tractable.

  11. Nudge for (the Public Good: How Defaults Can Affect Cooperation.

    Directory of Open Access Journals (Sweden)

    Toke R Fosgaard

    Full Text Available In this paper we test the effect of non-binding defaults on the level of contribution to a public good. We manipulate the default numbers appearing on the decision screen to nudge subjects toward a free-rider strategy or a perfect conditional cooperator strategy. Our results show that the vast majority of our subjects did not adopt the default numbers, but their stated strategy was affected by the default. Moreover, we find that our manipulation spilled over to a subsequent repeated public goods game where default was not manipulated. Here we found that subjects who previously saw the free rider default were significantly less cooperative than those who saw the perfect conditional cooperator default.

  12. Nudge for (the Public) Good: How Defaults Can Affect Cooperation.

    Science.gov (United States)

    Fosgaard, Toke R; Piovesan, Marco

    2015-01-01

    In this paper we test the effect of non-binding defaults on the level of contribution to a public good. We manipulate the default numbers appearing on the decision screen to nudge subjects toward a free-rider strategy or a perfect conditional cooperator strategy. Our results show that the vast majority of our subjects did not adopt the default numbers, but their stated strategy was affected by the default. Moreover, we find that our manipulation spilled over to a subsequent repeated public goods game where default was not manipulated. Here we found that subjects who previously saw the free rider default were significantly less cooperative than those who saw the perfect conditional cooperator default. PMID:26717569

  13. Vitamin D as Supplementary Treatment for Tuberculosis

    DEFF Research Database (Denmark)

    Wejse, Christian; Gomes, Victor F; Rabna, Paulo;

    2009-01-01

    RATIONALE: Vitamin D has been shown to be involved in host immune response towards M. tuberculosis. OBJECTIVE: To test whether vitamin D supplementation of TB patients improved clinical outcome and reduced mortality. METHODS: We conducted a randomized double-blind placebo-controlled trial in TB...... clinics at a Demographic Surveillance Site in Guinea Bissau. We included 365 adult TB patients starting anti-tuberculosis treatment, 281 completed 12 month follow-up. The intervention was 100,000 IU cholecalciferol or placebo at inclusion and again at 5 and 8 months after start of treatment. Measurements...

  14. Impact of Physician's Education on Adherence to Tuberculosis Treatment for Patients of Low Socioeconomic Status in Bangladesh

    OpenAIRE

    Lee, Shinwon; Khan, Omar Faruk; Seo, Jeong Ho; Kim, Dong Yeon; Park, Kyung-Hwa; Jung, Sook-In; Chung, Eun-Kyung; Jang, Hee-Chang

    2013-01-01

    Successful tuberculosis control depends on good adherence to treatment. Yet, limited data are available on the efficacy of methods for improving the adherence of patients of low socioeconomic status. We evaluated the impact of physician-provided patient education on adherence to anti-tuberculosis medication in a low socioeconomic status and resource-limited setting. A pre-/post-intervention study was conducted at a suburban primary health care clinic in Bangladesh where an intensive education...

  15. Utility maximization in incomplete markets with default

    CERN Document Server

    Lim, Thomas

    2008-01-01

    We adress the maximization problem of expected utility from terminal wealth. The special feature of this paper is that we consider a financial market where the price process of risky assets can have a default time. Using dynamic programming, we characterize the value function with a backward stochastic differential equation and the optimal portfolio policies. We separately treat the cases of exponential, power and logarithmic utility.

  16. Advanced Methods for Loss Given Default Estimation

    OpenAIRE

    Töws, Eugen

    2016-01-01

    This thesis consists of three essays on the estimation of the risk parameter LGD. The first essay (Hartmann-Wendels, Miller, and Töws, 2014, Loss given default for leasing: Parametric and nonparametric estimations) fills a gap in LGD related literature by focusing on elementary differences of the examined estimation approaches. We find that finite mixture models are quite capable of reproducing the unusual shape of the LGD distribution. However, out-of-sample the estimation error increases si...

  17. Default contagion risks in Russian interbank market

    OpenAIRE

    Leonidov, A. V.; E. L. Rumyantsev

    2014-01-01

    Systemic risks of default contagion in the Russian interbank market are investigated. The analysis is based on considering the bow-tie structure of the weighted oriented graph describing the structure of the interbank loans. A probabilistic model of interbank contagion explicitly taking into account the empirical bow-tie structure reflecting functionality of the corresponding nodes (borrowers, lenders, borrowers and lenders simultaneously), degree distributions and disassortativity of the int...

  18. Recalculating default values for palm oil

    OpenAIRE

    Pehnelt, Gernot; Vietze, Christoph

    2011-01-01

    On 05 December 2010, the Renewable Energy Directive (RED) came into force in the EU. Member States are still working to fully transpose the Directive into national law and establish a framework for achieving their legally binding greenhouse gas (GHG) emission reductions. However, governments got off to a slow start as debate continues on the validity of the directives foundations including the default values used to measure the sustainability of biofuels. Only sustainable biofuels can be coun...

  19. The Australian Credit Default Swap Markets

    OpenAIRE

    Daniel Fabbro

    2011-01-01

    The Australian credit default swap (CDS) market has been increasingly used by financial institutions to trade and manage credit risk. As a result, there has been greater use of the market as a source of credit risk pricing information. Similarities between CDS and bonds allow pricing in the two markets to be compared. However, the CDS market has a greater tendency at times to be affected by poor liquidity, which complicates the interpretation of CDS pricing, particularly when there are large ...

  20. Credit Default Swaps and Sovereign Debt Markets

    OpenAIRE

    M. Kabir Hassan; Geoffrey M. Ngene; Jung Suk-Yu

    2011-01-01

    This study investigates the link between price discovery dynamics in sovereign credit default swaps (CDS) and bond markets and degree of financial integration of emerging markets. Using CDS and sovereign bond spreads, the price discovery mechanism was tested using a vector error correction model. Financial integration is measured using news-based methods. We find that sovereign CDS and bond markets are cointegrated. In 57 percent of times, the CDS market leads in price discovery by adjusting ...

  1. Counting Processes for Retail Default Modeling

    DEFF Research Database (Denmark)

    Kiefer, Nicholas Maximilian; Larson, C. Erik

    Counting processes provide a very flexible framework for modeling discrete events occurring over time. Estimation and interpretation is easy, and links to more familiar approaches are at hand. The key is to think of data as "event histories," a record of times of switching between states in a dis......Counting processes provide a very flexible framework for modeling discrete events occurring over time. Estimation and interpretation is easy, and links to more familiar approaches are at hand. The key is to think of data as "event histories," a record of times of switching between states...... in a discrete state space. In a simple case, the states could be default/non-default; in other models relevant for credit modeling the states could be credit scores or payment status (30 dpd, 60 dpd, etc.). Here we focus on the use of stochastic counting processes for mortgage default modeling, using data...... on high LTV mortgages. Borrowers seeking to finance more than 80% of a house's value with a mortgage usually either purchase mortgage insurance, allowing a first mortgage greater than 80% from many lenders, or use second mortgages. Are there differences in performance between loans financed...

  2. Credit Default Swaps networks and systemic risk

    Science.gov (United States)

    Puliga, Michelangelo; Caldarelli, Guido; Battiston, Stefano

    2014-11-01

    Credit Default Swaps (CDS) spreads should reflect default risk of the underlying corporate debt. Actually, it has been recognized that CDS spread time series did not anticipate but only followed the increasing risk of default before the financial crisis. In principle, the network of correlations among CDS spread time series could at least display some form of structural change to be used as an early warning of systemic risk. Here we study a set of 176 CDS time series of financial institutions from 2002 to 2011. Networks are constructed in various ways, some of which display structural change at the onset of the credit crisis of 2008, but never before. By taking these networks as a proxy of interdependencies among financial institutions, we run stress-test based on Group DebtRank. Systemic risk before 2008 increases only when incorporating a macroeconomic indicator reflecting the potential losses of financial assets associated with house prices in the US. This approach indicates a promising way to detect systemic instabilities.

  3. Auto Default Gateway Settings for Virtual Machines in Servers using Default Gateway Weight Settings Protocol (DGW

    Directory of Open Access Journals (Sweden)

    Suman Dutta

    2014-11-01

    Full Text Available Availability is one of the most important concerns in the networking world. For any high available network, we need to maintain 99.99999% availability . That is why it is one of the most important facto rs to find out the single point of failure in the network architecture and eliminate that single point of fa ilure (SPOF from physical network and logical network. S POF in our server infrastructure has been analysed in terms of communicating with the router for forwa rding traffic with multiple routers. We have develo ped an algorithm that will automatically select default gateway into the network interface card of virtual machines. The proposed algorithm will automatically enable Default Gateway Weight settings (DGW protocol among routers by configuring Network inter face card with default gateway of all routers. The proposed protocol works based on weight settings fo r the multiple default gateway configuration in the host. There will be heartbeat communication and re- convergence will be performed within the shortest possible time. Lowest weight setting will select th e path for packet forwarding through specified rout ers related with the default gateway from the virtual m achine

  4. Time-kill kinetics of anti-tuberculosis drugs, and emergence of resistance, in relation to metabolic activity of Mycobacterium tuberculosis.

    NARCIS (Netherlands)

    Steenwinkel, J.E. de; Knegt, G.J. de; Kate, M.T. Ten; Belkum, A. van; Verbrugh, H.A.; Kremer, K.; Soolingen, D. van; Bakker-Woudenberg, I.A.

    2010-01-01

    OBJECTIVES: The pharmacodynamics of tuberculosis (TB) treatment should be further explored, to prevent emergence of resistance, treatment failure and relapse of infection. The diagnostic drug susceptibility tests guiding TB therapy investigate metabolically active Mycobacterium tuberculosis (Mtb) is

  5. Conceptual and Statistical Issues Regarding the Probability of Default and Modeling Default Risk

    Directory of Open Access Journals (Sweden)

    Emilia TITAN

    2011-03-01

    Full Text Available In today’s rapidly evolving financial markets, risk management offers different techniques in order to implement an efficient system against market risk. Probability of default (PD is an essential part of business intelligence and customer relation management systems in the financial institutions. Recent studies indicates that underestimating this important component, and also the loss given default (LGD, might threaten the stability and smooth running of the financial markets. From the perspective of risk management, the result of predictive accuracy of the estimated probability of default is more valuable than the standard binary classification: credible or non credible clients. The Basle II Accord recognizes the methods of reducing credit risk and also PD and LGD as important components of advanced Internal Rating Based (IRB approach.

  6. Residential Mortgage Default and Consumer Bankruptcy: Theory and Empirical Evidence

    OpenAIRE

    Michelle White; Wenli Li

    2011-01-01

    In this paper we develop a theory where homeowners make joint decisions in financial distress as whether to file for bankruptcy or default on their mortgages. The theory models explicitly institutional details, the federal bankruptcy law and the state foreclosure laws, that govern the two default events separately and their interactions. In particular, we derive regions (defined by households asset, liability, and income positions) where homeowners default on both loans, on one of them, and o...

  7. Indifference of Defaultable Bonds with Stochastic Intensity models

    OpenAIRE

    Regis Houssou; Olivier Besson

    2010-01-01

    The utility-based pricing of defaultable bonds in the case of stochastic intensity models of default risk is discussed. The Hamilton-Jacobi- Bellman (HJB) equations for the value functions is derived. A finite difference method is used to solve this problem. The yield-spreads for both buyer and seller are extracted. The behaviour of the spread curve given the default intensity is analyzed. Finally the impacts of the risk aversion and the correlation coefficient are discussed.

  8. The Role of Demand Response in Default Service Pricing

    International Nuclear Information System (INIS)

    In designing default service for competitive retail markets, demand response has been an afterthought at best. But that may be changing, as states that initiated customer choice in the past five to seven years reach an important juncture in retail market design and consider an RTP-type default service for large commercial and industrial customers. The authors describe the experience to date with RTP as a default service, focusing on its role as an instrument for cultivating price-responsive demand. (author)

  9. Default logic as a formalism for understanding commonsense reasoning

    OpenAIRE

    Amati, Gianni; Carlucci Aiello, Luigia; Pirri, Fiora

    1996-01-01

    Commonsense reasoning is the reasoning of agents interacting with the real world. Non monotonic reasoning is a well developed research area gathering the logical formalisms that treat commonsense reasoning. One of the best known of such formalisms is Default logic. In this paper we discuss Default logic at both the proof-theoretic and semantics levels and show that Default logic provides a clear and formal framework to understand the logical nature of commonsense reasoning.

  10. Default contagion risks in Russian interbank market

    Science.gov (United States)

    Leonidov, A. V.; Rumyantsev, E. L.

    2016-06-01

    Systemic risks of default contagion in the Russian interbank market are investigated. The analysis is based on considering the bow-tie structure of the weighted oriented graph describing the structure of the interbank loans. A probabilistic model of interbank contagion explicitly taking into account the empirical bow-tie structure reflecting functionality of the corresponding nodes (borrowers, lenders, borrowers and lenders simultaneously), degree distributions and disassortativity of the interbank network under consideration based on empirical data is developed. The characteristics of contagion-related systemic risk calculated with this model are shown to be in agreement with those of explicit stress tests.

  11. Nudge for (the Public) Good: How Defaults Can Affect Cooperation

    OpenAIRE

    Fosgaard, Toke R.; Marco Piovesan

    2015-01-01

    In this paper we test the effect of non-binding defaults on the level of contribution to a public good. We manipulate the default numbers appearing on the decision screen to nudge subjects toward a free-rider strategy or a perfect conditional cooperator strategy. Our results show that the vast majority of our subjects did not adopt the default numbers, but their stated strategy was affected by the default. Moreover, we find that our manipulation spilled over to a subsequent repeated public go...

  12. 多重可违约基金的定价%PRICING OF MULTIPLE DEFAULTABLE BOND

    Institute of Scientific and Technical Information of China (English)

    简志宏; 李楚霖

    2002-01-01

    In this paper a generalized defaultable bond pricing formula is derived by assuming that there exists a defaultable forward rate term structure and that firms in the economy interact when default occurs.Generally,The risk-neutral default intensity λQ is not equal to the empirical or actual default intensity λ.This paper proves that multiple default intensities are invariant under equivalent martingale transformation,given a well-diversified portfolio corresponding to the defaultable bond.Thus one can directly apply default intensities and fractional losses empirically estimated to the evaluation of defaultable bonds or contingent claims.

  13. Therapeutic efficacy of drug susceptibility test-guided individualized anti-tuberculosis chemotherapy for spinal tuberculosis%脊柱结核个体化药物治疗的临床效果观察

    Institute of Scientific and Technical Information of China (English)

    吴铮; 张泽华; 许建中

    2010-01-01

    目的 探讨药敏试验指导下的脊柱结核个体化药物治疗的临床效果.方法 选择2005年8月至2010年1月诊治的132例脊柱结核手术患者进行结核分枝杆菌培养和药敏试验,随访超过12个月者62例纳入本研究,其中男性37例,女性25例;年龄4~67岁,平均33.6岁.患者均接受手术治疗,术中收集脓液、干酪样组织,常规处理后接种培养液,使用BACT/ALERT 3D细菌自动培养分析系统快速培养,培养阳性者采用改良罗氏培养液按绝对浓度法进行药敏试验,并根据结果制定抗结核化疗方案.术后1、3、6、9、12个月复查各1次,以后每6个月复查1次,观察临床表现及红细胞沉降率、X线片、三维CT、MRI的变化,分析局部及全身结核病转归、术区骨性融合等情况.结果 检测耗时28~58 d,平均42 d;培养阳性率45.2%(28/62).耐药率达24.2%,其中异烟肼12.9%、利福平4.8%、乙胺丁醇3.2%、链霉素9.7%、帕司烟肼6.4%、左氧氟沙星14.5%、利福喷汀1.6%.随访时间12~44个月,平均21个月.术后2周内切口愈合率98.4%(61/62).椎间植骨均获Ⅰ级骨性融合,融合时间8~12个月.结论 耐药结核形势严峻,药敏试验指导下的脊柱结核个体化药物治疗是减少复发、复治的关键.%Objective To investigate the efficacy of individualized anti-tuberculosis chemotherapy guided by drug susceptibility testing for spinal tuberculosis through analyses on the post-operative follow-up outcomes. Methods The diagnoses of spinal tuberculosis were established by clinical, radiological and histological evaluation in 132 patients who were admitted from August 2005 to January 2010, 62 patients (37 male and 25 female) with follow-up more than 12 months in this study. The average age was 33. 6 years (ranging from 4-67 years). The infected samples were collected during surgery. After processed in a routine laboratory procedure, the samples were inoculated into vials of the BACT/ALERT 3D

  14. The Big Five default brain: functional evidence.

    Science.gov (United States)

    Sampaio, Adriana; Soares, José Miguel; Coutinho, Joana; Sousa, Nuno; Gonçalves, Óscar F

    2014-11-01

    Recent neuroimaging studies have provided evidence that different dimensions of human personality may be associated with specific structural neuroanatomic correlates. Identifying brain correlates of a situation-independent personality structure would require evidence of a stable default mode of brain functioning. In this study, we investigated the correlates of the Big Five personality dimensions (Extraversion, Neuroticism, Openness/Intellect, Agreeableness, and Conscientiousness) and the default mode network (DMN). Forty-nine healthy adults completed the NEO-Five Factor. The results showed that the Extraversion (E) and Agreeableness (A) were positively correlated with activity in the midline core of the DMN, whereas Neuroticism (N), Openness (O), and Conscientiousness (C) were correlated with the parietal cortex system. Activity of the anterior cingulate cortex was positively associated with A and negatively with C. Regions of the parietal lobe were differentially associated with each personality dimension. The present study not only confirms previous functional correlates regarding the Big Five personality dimensions, but it also expands our knowledge showing the association between different personality dimensions and specific patterns of brain activation at rest.

  15. 24 CFR 203.333 - Reinstatement of defaulted mortgage.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Reinstatement of defaulted mortgage... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES SINGLE FAMILY MORTGAGE INSURANCE Contract Rights and Obligations Default Under Mortgage §...

  16. Translation Compensation for Cultural Default in Lexical Level

    Institute of Scientific and Technical Information of China (English)

    杨瑞锋

    2015-01-01

    Cultural default is a concept derived from the cultural comparison between different cultures. People sharing the same culture do not realize its existence;however it often gives rise to obstacles for translators. By means of case studies, this paper dis⁃cusses the translation compensation for cultural default in lexical level.

  17. Re-Setting Music Education's "Default Settings"

    Science.gov (United States)

    Regelski, Thomas A.

    2013-01-01

    This paper explores the effects and problems of one highly influential default setting of the "normal style template" of music education and proposes some alternatives. These do not require abandoning all traditional templates for school music. But re-setting the default settings does depend on reconsidering the promised function of…

  18. Structural RFV : Recovery Form and Defaultable Debt Analysis

    NARCIS (Netherlands)

    Guha, R.; Sbuelz, A.

    2003-01-01

    Receiving the same fractional recovery of par at default for bonds of the same issuer and seniority, regardless of remaining maturity, has been labelled in the academic literature as a Recovery of Face Value at Default (RFV).Such a recovery form results from language found in typical bond indentures

  19. 46 CFR 502.605 - Payment of penalty: Method; default.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 9 2010-10-01 2010-10-01 false Payment of penalty: Method; default. 502.605 Section 502... Payment of penalty: Method; default. (a) Method. Payment of penalties by the respondent is to be made by... instruments submitted in payment of claims shall be made payable to the Federal Maritime Commission....

  20. DKLFRS:A Default Knowledge Logical Framework Representation System

    Institute of Scientific and Technical Information of China (English)

    范仲春; 邢汉承

    1992-01-01

    The traditional resasoning system based on first order predicate logic can't represent and handle default knowledge,This paper presents a logical framework representation approach for default reasoning.Based on Mixed SLDNF-resolution,a nonmonotonic reasoning system has been constructed.

  1. Default Reasoning and Belief Revision: A Syntax-Independent Approach

    Institute of Scientific and Technical Information of China (English)

    张东摩; 朱朝晖; 陈世福

    2000-01-01

    As an important variant of Reiter's default logic, Poole (1988) de veloped a nonmonotonic reasoning framework in the classical first-order language. Brewka and Nebel extended Poole's approach in order to enable a representation of priorities between defaults. In this paper a general framework for default reasoning is presented, which can be viewed as a generalization of the three approaches above. It is proved that the syntax-independent default reasoning in this framework is iden tical to the general belief revision operation introduced by Zhang et al. (1997). This result provides a solution to the problem whether there is a correspondence between belief revision and default logic for the infinite case. As a by-product, an answer to the question, raised by Mankinson and Gairdenfors (1991), is also given about whether there is a counterpart contraction in nonmonotonic logic.

  2. Association of the CYP2B6 gene with anti-tuberculosis drug-induced hepatotoxicity in a Brazilian Amazon population

    OpenAIRE

    Débora Christina Ricardo Oliveira Fernandes; Ney Pereira Carneiro Santos; Milene Raiol Moraes; Ana Cristina Oliveira Braga; Cleonardo Augusto Silva; Andrea Ribeiro-dos-Santos; Sidney Santos

    2015-01-01

    Objectives: The treatment of tuberculosis (TB) remains a challenge owing to the high incidence of drug-induced hepatotoxicity. The aim of this study was to examine the effect of two gene polymorphisms, one in the CYP2B6 (rs3745274) gene and one in the CYP3A5 (rs776746) gene, on the development of hepatotoxicity in patients treated with anti-TB drugs in a Brazilian Amazon population. Methods: TB patients who were treated with anti-TB drugs were examined for hepatotoxicity, an adverse effect...

  3. Pediatric tuberculous meningitis: Model-based approach to determining optimal doses of the anti-tuberculosis drugs rifampin and levofloxacin for children.

    Science.gov (United States)

    Savic, R M; Ruslami, R; Hibma, J E; Hesseling, A; Ramachandran, G; Ganiem, A R; Swaminathan, S; McIlleron, H; Gupta, A; Thakur, K; van Crevel, R; Aarnoutse, R; Dooley, K E

    2015-12-01

    Pediatric tuberculous meningitis (TBM) is a highly morbid, often fatal disease. Standard treatment includes isoniazid, rifampin, pyrazinamide, and ethambutol. Current rifampin dosing achieves low cerebrospinal fluid (CSF) concentrations, and CSF penetration of ethambutol is poor. In adult trials, higher-dose rifampin and/or a fluoroquinolone reduced mortality and disability. To estimate optimal dosing of rifampin and levofloxacin for children, we compiled plasma and CSF pharmacokinetic (PK) and outcomes data from adult TBM trials plus plasma PK data from children. A population PK/pharmacodynamic (PD) model using adult data defined rifampin target exposures (plasma area under the curve (AUC)0-24 = 92 mg*h/L). Levofloxacin targets and rifampin pediatric drug disposition information were literature-derived. To attain target rifampin exposures, children require daily doses of at least 30 mg/kg orally or 15 mg/kg intravenously (i.v.). From our pediatric population PK model, oral levofloxacin doses needed to attain exposure targets were 19-33 mg/kg. Our results provide data-driven guidance to maximize pediatric TBM treatment while we await definitive trial results. PMID:26260983

  4. Using default inheritance to describe LTAG

    CERN Document Server

    Evans, R; Weir, D; Evans, Roger; Gazdar, Gerald; Weir, David

    1995-01-01

    We present the results of an investigation into how the set of elementary trees of a Lexicalized Tree Adjoining Grammar can be represented in the lexical knowledge representation language DATR (Evans & Gazdar 1989a,b). The LTAG under consideration is based on the one described in Abeille et al. (1990). Our approach is similar to that of Vijay-Shanker & Schabes (1992) in that we formulate an inheritance hierarchy that efficiently encodes the elementary trees. However, rather than creating a new representation formalism for this task, we employ techniques of established utility in other lexically-oriented frameworks. In particular, we show how DATR's default mechanism can be used to eliminate the need for a non-immediate dominance relation in the descriptions of the surface LTAG entries. This allows us to embed the tree structures in the feature theory in a manner reminiscent of HPSG subcategorisation frames, and hence express lexical rules as relations over feature structures.

  5. Sovereign Default Analysis through Extreme Events Identification

    Directory of Open Access Journals (Sweden)

    Vasile George MARICA

    2015-06-01

    Full Text Available This paper investigates contagion in international credit markets through the use of a novel jump detection technique proposed by Chan and Maheuin (2002. This econometrical methodology is preferred because it is non-linear by definition and not a subject to volatility bias. Also, the identified jumps in CDS premiums are considered as outliers positioned beyond any stochastic movement that can and is already modelled through well-known linear analysis. Though contagion is hard to define, we show that extreme discrete movements in default probabilities inferred from CDS premiums can lead to sound economic conclusions about the risk profile of sovereign nations in international bond markets. We find evidence of investor sentiment clustering for countries with unstable political regimes or that are engaged in armed conflict. Countries that have in their recent history faced currency or financial crises are less vulnerable to external unexpected shocks. First we present a brief history of sovereign defaults with an emphasis on their increased frequency and geographical reach, as financial markets become more and more integrated. We then pass to a literature review of the most important definitions for contagion, and discuss what quantitative methods are available to detect the presence of contagion. The paper continues with the details for the methodology of jump detection through non-linear modelling and its use in the field of contagion identification. In the last sections we present the estimation results for simultaneous jumps between emerging markets CDS and draw conclusions on the difference of behavior in times of extreme movement versus tranquil periods.

  6. NAT2 variants are associated with drug-induced liver injury caused by anti-tuberculosis drugs in Indonesian patients with tuberculosis.

    Science.gov (United States)

    Yuliwulandari, Rika; Susilowati, Retno Wilujeng; Wicaksono, Britanto Dani; Viyati, Kencono; Prayuni, Kinasih; Razari, Intan; Kristin, Erna; Syafrizal; Subagyo; Sri Diana, Eva; Setiawati, Suci; Ariyani, Aziza; Mahasirimongkol, Surakameth; Yanai, Hideki; Mushiroda, Taisei; Tokunaga, Katsushi

    2016-06-01

    Drug-induced liver injury (DILI) is the most common adverse drug reaction in the treatment of tuberculosis (TB). Several studies showed that patients with TB and the slow-acetylator phenotype caused by NAT2 variants are highly susceptible to DILI caused by anti-TB drugs, hereafter designated AT-DILI. However, the role of NAT2 variants in AT-DILI has never been assessed for an Indonesian population. We recruited 50 patients with TB and AT-DILI and 191 patients with TB but without AT-DILI; we then used direct DNA sequencing to assess single-nucleotide polymorphisms in the coding region of NAT2. NAT2*6A was significantly associated with susceptibility to AT-DILI (P=7.7 × 10(-4), odds ratio (OR)=4.75 (1.8-12.55)). Moreover, patients with TB and the NAT2-associated slow-acetylator phenotype showed higher risk of AT-DILI than patients with the rapid- or intermediate-acetylator phenotypes (P=1.7 × 10(-4), OR=3.45 (1.79-6.67)). In conclusion, this study confirms the significance of the association between slow-acetylator NAT2 variants and susceptibility to AT-DILI in an Indonesian population.

  7. Hepatitis C virus co-infection increases the risk of anti-tuberculosis drug-induced hepatotoxicity among patients with pulmonary tuberculosis.

    Directory of Open Access Journals (Sweden)

    Nino Lomtadze

    Full Text Available BACKGROUND: The country of Georgia has a high prevalence of tuberculosis (TB and hepatitis C virus (HCV infection. PURPOSE: To determine whether HCV co-infection increases the risk of incident drug-induced hepatitis among patients on first-line anti-TB drug therapy. METHODS: Prospective cohort study; HCV serology was obtained on all study subjects at the time of TB diagnosis; hepatic enzyme tests (serum alanine aminotransferase [ALT] activity were obtained at baseline and monthly during treatment. RESULTS: Among 326 study patients with culture-confirmed TB, 68 (21% were HCV co-infected, 14 (4.3% had chronic hepatitis B virus (HBV infection (hepatitis B virus surface antigen positive [HBsAg+], and 6 (1.8% were HIV co-infected. Overall, 19% of TB patients developed mild to moderate incident hepatotoxicity. In multi-variable analysis, HCV co-infection (adjusted Hazards Ratio [aHR]=3.2, 95% CI=1.6-6.5 was found to be an independent risk factor for incident anti-TB drug-induced hepatotoxicity. Survival analysis showed that HCV co-infected patients developed hepatitis more quickly compared to HCV seronegative patients with TB. CONCLUSION: A high prevalence of HCV co-infection was found among patients with TB in Georgia. Drug-induced hepatotoxicity was significantly associated with HCV co-infection but severe drug-induced hepatotoxicity (WHO grade III or IV was rare.

  8. Drug-induced liver injury caused by anti-tuberculosis drugs%抗结核药所致药物性肝损害

    Institute of Scientific and Technical Information of China (English)

    李锋; 卢水华

    2014-01-01

    Incidence of antituberculosis drug-induced liver injury (DILI) is different according to reports of various areas, and different anti-TB drugs have different chances to cause liver injury. Pyrazinamide and rifampicin are the most common drugs resulted in DILI in our country. The related risk factors of DILI includes gender, age, lifestyle, genetic factors and complications. The main mechanism of anti-TB DILI includes liver toxicity and allergic liver damage. The patients with DILI require closely observation and have enough rest. The anti-TB regiment should stop if necessary, and protective therapy should be given. Most patients with DILI could recover gradually after proper medication. After liver functional improvement, the anti-TB regiment should be chosen carefully according to the patient's case history. Prophylactic treatment for hepatic injury is currently not conclusive. Therefore, the patients’ liver function should be paid attention to during the overall anti-TB process, and the factors that could cause hepatic damage other than anti-TB drugs should be avoided comprehensively.%不同国家、地区报道的抗结核药物性肝损伤(DILI)发生率不同,不同抗结核药物引起DILI的概率也不相同。在我国吡嗪酰胺与利福平是最常见的导致DILI的药物。DILI的相关危险因素包括:性别和年龄、生活方式、遗传因素、并发症等。抗结核药物发生DILI的主要机制包括中毒性肝损害和变态反应性肝损害。发生DILI后需密切观察,可给予停药,充分的休息,积极保肝治疗,大部分患者可逐渐恢复。应当根据患者的具体情况酌情选择抗结核方案。预防性保肝治疗目前正在研究中。抗结核过程中应当关注导致患者的肝功能指标,避免导致肝损伤的其他因素,更全面地保护肝脏。

  9. Additive Intensity Regression Models in Corporate Default Analysis

    DEFF Research Database (Denmark)

    Lando, David; Medhat, Mamdouh; Nielsen, Mads Stenbo;

    2013-01-01

    We consider additive intensity (Aalen) models as an alternative to the multiplicative intensity (Cox) models for analyzing the default risk of a sample of rated, nonfinancial U.S. firms. The setting allows for estimating and testing the significance of time-varying effects. We use a variety...... of model checking techniques to identify misspecifications. In our final model, we find evidence of time-variation in the effects of distance-to-default and short-to-long term debt. Also we identify interactions between distance-to-default and other covariates, and the quick ratio covariate is significant...

  10. Macro-economy in models for default probability.

    OpenAIRE

    Geurdes, Han / J. F.

    2011-01-01

    We inspect the question how to adapt to macro-economical variables those probability of default (PD) estimates where Merton's model assumptions cannot be used. The need for this is to obtain trustworthy estimates of PD from a given economical situation. The structure of a known market-credit risk model is adapted. The key concept in this adaptation is the assumption of a different probabilistic situation for a firm before and at (first) default. If a corporate firm defaults we use a differ...

  11. A Note on Pricing Options on Defaultable Stocks

    CERN Document Server

    Bayraktar, Erhan

    2007-01-01

    In this note, we develop stock option price approximations for a model which takes both the risk o default and the stochastic volatility into account. We also let the intensity of defaults be influenced by the volatility. We show that it might be possible to infer the risk neutral default intensity from the stock option prices. Our option price approximation has a rich implied volatility surface structure and fits the data implied volatility well. Our calibration exercise shows that an effective hazard rate from bonds issued by a company can be used to explain the implied volatility skew of the implied volatility of the option prices issued by the same company.

  12. Local Risk-Minimization for Defaultable Claims with Recovery Process

    Energy Technology Data Exchange (ETDEWEB)

    Biagini, Francesca, E-mail: biagini@mathematik.uni-muenchen.de [LMU, Department of Mathematics (Germany); Cretarola, Alessandra, E-mail: alessandra.cretarola@dmi.unipg.it [Universita degli Studi di Perugia, Dipartimento di Matematica e Informatica (Italy)

    2012-06-15

    We study the local risk-minimization approach for defaultable claims with random recovery at default time, seen as payment streams on the random interval [0,{tau} Logical-And T], where T denotes the fixed time-horizon. We find the pseudo-locally risk-minimizing strategy in the case when the agent information takes into account the possibility of a default event (local risk-minimization with G-strategies) and we provide an application in the case of a corporate bond. We also discuss the problem of finding a pseudo-locally risk-minimizing strategy if we suppose the agent obtains her information only by observing the non-defaultable assets.

  13. 34 CFR Appendix A to Subpart N of... - Sample Default Prevention Plan

    Science.gov (United States)

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false Sample Default Prevention Plan A Appendix A to Subpart... Default Rates Pt. 668, Subpt. N, App. A Appendix A to Subpart N of Part 668—Sample Default Prevention Plan This appendix is provided as a sample plan for those institutions developing a default prevention...

  14. Long-Term Contracts Under the Threat of Supplier Default

    OpenAIRE

    Robert Swinney; Serguei Netessine

    2009-01-01

    Contracting with suppliers prone to default is an increasingly common problem in some industries, particularly automotive manufacturing. We model this phenomenon as a two-period contracting game with two identical suppliers, a single buyer, deterministic demand, and uncertain production costs. The suppliers are distressed at the start of the game and do not have access to external sources of capital; hence, revenues from the buyer are crucial in determining whether default occurs. The product...

  15. Default and Risk Premia in Microfinance Group Lending

    OpenAIRE

    Simmons, P; N Tantisantiwong (Southampton)

    2014-01-01

    For a risk neutral lender and a group of borrowers facing identical revenue risks we compare individual loans and group lending. We stress the importance of group liquidity in defining the necessary risk premium. There are no welfare differences between the loan forms. However, the default rates and risk premia vary ambiguously between the loan forms. Simulations replicating empirical interest rates and default rates show that the group interest rate is lower for a larger group while the effe...

  16. Information Sharing, Lending and Defaults: Cross-Country Evidence

    OpenAIRE

    Jappelli, Tullio; Pagano, Marco

    1999-01-01

    Theory predicts that information sharing among lenders attenuates adverse selection and moral hazard, and can therefore increase lending and reduce default rates. To test these predictions, we construct a new international data set on private credit bureaus and public credit registers. We find that bank lending is higher and proxies for default rates are lower in countries where lenders share information, regardless of the private or public nature of the information sharing mechanism. We also...

  17. Comparing the effects of defaults in organ donation systems

    OpenAIRE

    van Dalen, H.P.; Henkens, K.

    2014-01-01

    The ability of patients in many parts of the world to benefit from transplantation is limited by growing shortages of transplantable organs. The choice architecture of donation systems is said to play a pivotal role in explaining this gap. In this paper we examine the question how different defaults affect the decision to register as organ donor. Three defaults in organ donation systems are compared: mandated choice, presumed consent and explicit consent. Hypothetical choices from a national ...

  18. Sukuk Defaults: On Distress Resolution in Islamic Finance

    OpenAIRE

    van Wijnbergen, Sweder; Zaheer, Sajjad

    2013-01-01

    Islamic strictures require investors to share risks with the entrepreneurs they finance. Sukuk (Islamic securities) come mostly in two varieties, musharakah (basically a joint venture agreement) and ijarah (more like an operational lease agreement). Yet defaults did happen, even in the case of musharakah (joint venture) sukuk discussed in this study. So is Islamic finance failing to deliver on its promises? To answer that question, we analyse four major defaults on Sukuk that have happened re...

  19. Credit Risk, Market Sentiment and Randomly-Timed Default

    OpenAIRE

    Brody, Dorje C.; Hughston, Lane P.; Andrea Macrina

    2010-01-01

    We propose a model for the credit markets in which the random default times of bonds are assumed to be given as functions of one or more independent "market factors". Market participants are assumed to have partial information about each of the market factors, represented by the values of a set of market factor information processes. The market filtration is taken to be generated jointly by the various information processes and by the default indicator processes of the various bonds. The valu...

  20. Determining threshold default risk criterion for trade credit granting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To solve the problem of setting threshold default risk criterion to select retailer eligible for trade credit granting, a novel method of solving simultaneous equations is proposed. This method is based on the bilevel programming modeling of trade credit decisions as an interaction between supplier and retailer. First, the bilevel programming is set up where the supplier decides on credit terms at the top level considering a retailer's default risk, and the retailer determines the order quantity at the lowe...

  1. An Empirical Analysis of Turkish Credit Default SWAPS

    OpenAIRE

    Hasan BAKLACI; Arslan, İlker

    2006-01-01

    Despite its widespread use globally, majority of the Turkish financial institutions are still unaware of Credit Default Swaps (CDS), stemming mainly from insufficient financial infrastructure and information base for credit derivatives. This study analyzes Turkish CDS from various perspectives. The findings exhibit that 10-year spreads are found to be overpriced, primarily due to the lack of liquidity in current CDS market in Turkey. Besides, the term structure of default probability estimati...

  2. An analysis of loan default determinants: the Spanish case

    OpenAIRE

    Climent Serrano, Salvador; Pavía Miralles, José Manuel

    2014-01-01

    The Spanish financial system is experiencing a very turbulent economic period in which loan defaults has lived an unprecedented increasing period, going from being less than 1% in 2004 to levels of above 13% in 2013. The impact of this, along with other circumstances, has led to the greatest financial restructuring ever made to date in Spain, with important macroeconomic and microeconomic consequences. This paper studies the determinants of delinquency (loan default) in Spanish credit institu...

  3. Drivers of corporate bankruptcy and default : study concerning Portuguese Companies

    OpenAIRE

    Morais, José Carlos de Matos

    2013-01-01

    My purpose with this dissertation is to investigate the relevance of financial and economic variables as predictors of corporate bankruptcy (default) in Portugal. Understanding the underlying issues behind corporate distress and failure is crucial for several areas particularly: granting (or not) a bank loan, managing credit risk and pricing debt. The present financial and economic crisis stimulated a growing interest on matters related to corporate default, ratings and scoring...

  4. Modelling Bonds & Credit Default Swaps using a Structural Model with Contagion

    OpenAIRE

    Helen Haworth; Christoph Reisinger; William Shaw

    2007-01-01

    This paper develops a two-dimensional structural framework for valuing credit default swaps and corporate bonds in the presence of default contagion. Modelling the values of related firms as correlated geometric Brownian motions with exponential default barriers, analytical formulae are obtained for both credit default swap spreads and corporate bond yields. The credit dependence structure is influenced by both a longer-term correlation structure as well as by the possibility of default conta...

  5. On the spillover of exchange rate risk into default risk

    Directory of Open Access Journals (Sweden)

    Božović Miloš

    2009-01-01

    Full Text Available In order to reduce the exchange-rate risk, banks in emerging markets are typically denominating their loans in foreign currencies. However, in the event of a substantial depreciation of the local currency, the payment ability of a foreign-currency borrower may be reduced significantly, exposing the lender to additional default risk. This paper analyses how the exchange-rate risk of foreign currency loans spills over into default risk. We show that in an economy where foreign currency loans are a dominant source of financing economic activity, depreciation of the local currency establishes a negative feedback mechanism that leads to higher default probabilities, reduced credit supply, and reduced growth. This finding has some important implications that may be of special interest for regulators and market participants in emerging economies.

  6. A Technical Note on Australian Default Superannuation Investment Strategies

    Directory of Open Access Journals (Sweden)

    Loretta Iskra

    2012-06-01

    Full Text Available Superannuation has become more complex over time. Individual investors are inclined to seek the ‘path of least resistance’ and invest in default investment funds which are typically concentrated in high risk assets. Understanding how these funds will meet the individual needs of members relative to their changing circumstances can provide peace of mind and confidence in the market. Given the value of superannuation as an investment in terms of the economy, it is paramount than an appropriate mechanism be in place for default fund investors. This paper will clarify the existing position relative to default fund investment options and outline future research which will provide the impetus for change in terms ofgovernment policy, the financial planning profession and for industry superannuation funds.

  7. Essays on bankruptcy, mortgage default, and regional migration

    OpenAIRE

    Oswald, F

    2015-01-01

    This thesis is about the role of housing as a consumption good and a risky asset, and how it interacts with other choices like consumption, default, and migration over the lifecycle. In the first chapter the focus is on a quasi natural experiment in the State of Nevada, which abolished deficiency judgments for purchase mortgage loans made after October 2009. We test the effect of the law change on mortgage supply and demand, as well as on mortgage default. We find strong evidence that lenders...

  8. Government interventions and default risk: Does one size fit all?

    NARCIS (Netherlands)

    Klomp, J.G.

    2013-01-01

    We examine the effectiveness of the financial sector rescue packages provided by the national governments during the 2008 financial crisis. This study questions the implicit assumption that government interventions have an uniform effect on the default risk of individual banks. After testing the res

  9. The Default Mode Network and Altered Consciousness in Epilepsy

    Directory of Open Access Journals (Sweden)

    Nathan B. Danielson

    2011-01-01

    Full Text Available The default mode network has been hypothesized based on the observation that specific regions of the brain are consistently activated during the resting state and deactivated during engagement with task. The primary nodes of this network, which typically include the precuneus/posterior cingulate, the medial frontal and lateral parietal cortices, are thought to be involved in introspective and social cognitive functions. Interestingly, this same network has been shown to be selectively impaired during epileptic seizures associated with loss of consciousness. Using a wide range of neuroimaging and electrophysiological modalities, decreased activity in the default mode network has been confirmed during complex partial, generalized tonic-clonic, and absence seizures. In this review we will discuss these three seizure types and will focus on possible mechanisms by which decreased default mode network activity occurs. Although the specific mechanisms of onset and propagation differ considerably across these seizure types, we propose that the resulting loss of consciousness in all three types of seizures is due to active inhibition of subcortical arousal systems that normally maintain default mode network activity in the awake state. Further, we suggest that these findings support a general “network inhibition hypothesis”, by which active inhibition of arousal systems by seizures in certain cortical regions leads to cortical deactivation in other cortical areas. This may represent a push-pull mechanism similar to that seen operating between cortical networks under normal conditions.

  10. 75 FR 60258 - Federal Acquisition Regulation; Termination for Default Reporting

    Science.gov (United States)

    2010-09-29

    ... Defective cost or pricing data. * * * * * (d) For each advisory audit received based on a postaward review... default and defective cost or pricing data, into the Past Performance Information System (PPIRS) and... included in PPIRS. Response: The Councils disagree. The Councils believe that defective cost or...

  11. 24 CFR 207.256a - Reinstatement of defaulted mortgage.

    Science.gov (United States)

    2010-04-01

    ... the Commissioner, in the manner prescribed in 24 CFR part 200, subpart B. ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Reinstatement of defaulted mortgage... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND...

  12. Sovereign default and the stability of inflation targeting regimes

    NARCIS (Netherlands)

    A. Schabert; S.J.G. van Wijnbergen

    2014-01-01

    We analyze the impact of interactions between monetary and fiscal policy on macroeconomic stability. We find that in the presence of sovereign default, macroeconomic stability requires monetary policy to be passive if the feedback from debt surprises back to the primary surplus is too weak. An activ

  13. Sovereign default and the stability of inflation targeting regimes

    NARCIS (Netherlands)

    A. Schabert; S.J.G. van Wijnbergen

    2011-01-01

    We analyse the impact of interactions between monetary and fiscal policy on macroeconomic stability. We find that in the presence of sovereign default beliefs a monetary policy, which aims to stabilize inflation through an active interest rate policy, will destabilize the economy if the feedback fro

  14. 48 CFR 1349.402-3 - Procedure for default

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Procedure for default 1349.402-3 Section 1349.402-3 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACT... Executive, and the action has been reviewed for legal sufficiency....

  15. A Comparative Study of Default Reasoning and Epistemic Processes

    Institute of Scientific and Technical Information of China (English)

    李未

    1993-01-01

    A comparative study between the theories of default reasoning and open logic is given.Some concepts of open logic,such as new premises,rejections by facts,reconstructions ,epistemic processes,and its limit are introduced to describe th evolution of hypotheses.An improved version of the limit theorem is given and proved.A model-theoretic interpretation of the closed normal defaults is given using the above concepts and the corresponding completeness is proved.Any extension of a closed normal default theory is proved to be the linit of a δ-partial increasing epistemic process of that theory,and vice versa.It is proved that there exist two distinct extensions of a closed normal default theory iff there is an δ-non-monotonic epistemic process of that theory.The completeness of Reiter's proof is also given and proved,in terms of the epistemic processes.Finally,the work is compared with Gaerdenfors's theory of knowledge in flux.

  16. Nonmonotonic Skeptical Consequence Relation in Constrained Default Logic

    Directory of Open Access Journals (Sweden)

    Mihaiela Lupea

    2010-12-01

    Full Text Available This paper presents a study of the nonmonotonic consequence relation which models the skeptical reasoning formalised by constrained default logic. The nonmonotonic skeptical consequence relation is defined using the sequent calculus axiomatic system. We study the formal properties desirable for a good nonmonotonic relation: supraclassicality, cut, cautious monotony, cumulativity, absorption, distribution. 

  17. Default Rate on Student Loans Falls for 2005 Fiscal Year

    Science.gov (United States)

    Basken, Paul

    2007-01-01

    The rate at which borrowers default on their federally guaranteed student loans has declined to 4.6 percent, in part because of a record number of consolidations, the Education Department announced last week. "Borrowers took advantage of the opportunity to lock in record-low interest rates by consolidating their federal student loans," the…

  18. 12 CFR 552.2-3 - Federal stock association created in connection with an association in default or in danger of...

    Science.gov (United States)

    2010-01-01

    ... with an association in default or in danger of default. 552.2-3 Section 552.2-3 Banks and Banking... default or in danger of default. Sections 552.2-1 and 552.2-2 of this part do not apply to a Federal stock... connection with an association in default or in danger of default. Incorporation and organization of...

  19. 12 CFR 543.7-1 - Federal savings association created in connection with an association in default or in danger of...

    Science.gov (United States)

    2010-01-01

    ... connection with an association in default or in danger of default. 543.7-1 Section 543.7-1 Banks and Banking... connection with an association in default or in danger of default. The preceding sections of this part do not... by the Office in connection with an association in default or in danger of default. Incorporation...

  20. Comparative evaluation of the Nitrate Reductase Assay and the Resazurin Microtitre Assay for drug susceptibility testing of Mycobacterium tuberculosis against first line anti-tuberculosis drugs Avaliação comparative dos métodos Nitrato Redutase e Microdiluição com Resazurina para testar a sensibilidade do Mycobacterium tuberculosis frente aos anti-tuberculosos de primeira linha

    Directory of Open Access Journals (Sweden)

    Karine O. Sanchotene

    2008-03-01

    Full Text Available Tuberculosis remains as a serious infection disease of worldwide distribution, with high morbidity and mortality, mainly in low socio-economic condition countries. The state of emergency of tuberculosis caused by the resistant and multidrug-resistant (MDR strains, became the main threat to the tuberculosis treatment and control programs. A fast detection method for the resistant strains will allow the implementation of an adequate treatment and contribute for controlling the dissemination of these resistant strains. This study evaluated the performance of the nitrate reductase assay in solid (NRA-LJ and liquid (NRA-7H9 media, to determine the susceptibility to first line anti-tuberculosis drugs: isoniazid (INH, rifampicin (RMP, ethambutol (EMB and streptomycin (SMR. Both methods NRA-LJ and NRA-7H9 were evaluated among 18 strains with a known susceptibility profile. The resazurin microtiter assay (REMA was performed as a reference method. One hundred percent of accordance was observed between NRA-7H9 and REMA for the four tested drugs. When the NRA-LJ method was compared to REMA, the sensitivity and the specificity to INH, RMP, EMB and SMR were 100%, 100 %, 85.7%, 76.9% and 80%, 100%, 75% and 80%, respectively. From the 57 clinical isolates of M. tuberculosis evaluated by NRA-7H9 and REMA, 56 (98.2% were sensitive to all antibiotics tested (INH, RMP, EMB and SMR by the NRA-7H9 method, while three of these strains were resistant to INH by REMA. One strain showed resistance to INH and RMP for both methods, and MIC of 1.0 µg/ml to INH for both methods, while MIC of 1.0 and 2.0 µg/ml to RMP for REMA and NRA-7H9, respectively. The three assays showed a high level of agreement for rapid detection of rifampicin and isoniazid resistance. Regarding rapidness, the detection of color change in the NRA method is within instants as compared to the overnight incubation required for the REMA test. NRA might represent an inexpensive and alternative assay for

  1. Modeling corporate defaults: Poisson autoregressions with exogenous covariates (PARX)

    DEFF Research Database (Denmark)

    Agosto, Arianna; Cavaliere, Guiseppe; Kristensen, Dennis;

    We develop a class of Poisson autoregressive models with additional covariates (PARX) that can be used to model and forecast time series of counts. We establish the time series properties of the models, including conditions for stationarity and existence of moments. These results are in turn used...... in the analysis of the asympotic properties of the maximum-likelihood estimators of the models. The PARX class of models is used to analyse the time series properties of monthly corporate defaults in the US in the period 1982-2011 using financial and economic variables as exogeneous covariates...... years economic and financial factors at the macro level are capable to explain a large portion of the correlation of US firms defaults over time....

  2. Exploring default mode and information flow on the web.

    Directory of Open Access Journals (Sweden)

    Mizuki Oka

    Full Text Available Social networking services (e.g., Twitter, Facebook are now major sources of World Wide Web (called "Web" dynamics, together with Web search services (e.g., Google. These two types of Web services mutually influence each other but generate different dynamics. In this paper, we distinguish two modes of Web dynamics: the reactive mode and the default mode. It is assumed that Twitter messages (called "tweets" and Google search queries react to significant social movements and events, but they also demonstrate signs of becoming self-activated, thereby forming a baseline Web activity. We define the former as the reactive mode and the latter as the default mode of the Web. In this paper, we investigate these reactive and default modes of the Web's dynamics using transfer entropy (TE. The amount of information transferred between a time series of 1,000 frequent keywords in Twitter and the same keywords in Google queries is investigated across an 11-month time period. Study of the information flow on Google and Twitter revealed that information is generally transferred from Twitter to Google, indicating that Twitter time series have some preceding information about Google time series. We also studied the information flow among different Twitter keywords time series by taking keywords as nodes and flow directions as edges of a network. An analysis of this network revealed that frequent keywords tend to become an information source and infrequent keywords tend to become sink for other keywords. Based on these findings, we hypothesize that frequent keywords form the Web's default mode, which becomes an information source for infrequent keywords that generally form the Web's reactive mode. We also found that the Web consists of different time resolutions with respect to TE among Twitter keywords, which will be another focal point of this paper.

  3. Sovereign Default, Private Sector Creditors and the IFIs

    OpenAIRE

    Boz, Emine

    2009-01-01

    This paper builds a model of a sovereign borrower that has access to credit from private sector creditors and an IFI. Private sector creditors and the IFI offer different debt contracts that are modelled based on the institutional frameworks of these two types of debt. We analyze the decisions of a sovereign on how to allocate its borrowing needs between these two types of creditors, and when to default on its debt to the private sector creditor. The numerical analysis shows that, consistent ...

  4. Essays on corporate default process: UK and France

    OpenAIRE

    Nigam, Nirjhar

    2011-01-01

    The thesis has been conducted upon a unique and primary database manually collected through courts and various reliable sources (governmental and non-governmental offices). This is the major strength of this thesis. With such a database, we built individual statistics on the corporate bankruptcies process in for two major European countries (France and United Kingdom). The collected data deals with the causes of financial default, the recovery rates of creditors, the process of decision makin...

  5. Defaultable Game Options in a Hazard Process Model

    Directory of Open Access Journals (Sweden)

    Tomasz R. Bielecki

    2009-01-01

    Full Text Available The valuation and hedging of defaultable game options is studied in a hazard process model of credit risk. A convenient pricing formula with respect to a reference filteration is derived. A connection of arbitrage prices with a suitable notion of hedging is obtained. The main result shows that the arbitrage prices are the minimal superhedging prices with sigma martingale cost under a risk neutral measure.

  6. The Role of Default Network Deactivation in Cognition and Disease

    OpenAIRE

    Anticevic, Alan; Cole, Michael W.; Murray, John D.; Corlett, Philip R.; Wang, Xiao-Jing; Krystal, John H.

    2012-01-01

    A considerable body of evidence has accumulated over recent years on the functions of the default-mode network (DMN) – a set of brain regions whose activity is high when the mind is not engaged in specific behavioral tasks and low during focused attention on the external environment. In this review, we focus on DMN suppression and its functional role in health and disease, summarizing evidence that spans several disciplines, including cognitive neuroscience, pharmacological neuroimaging, clin...

  7. Credit default swaps, bond spreads and the bond market

    OpenAIRE

    Zhu, Meicheng

    2014-01-01

    With the rapid development of the credit default swap (CDS) market, the issue of how the introduction of CDSs affects the corporate bond market has been of particular interest to researchers and policy makers. This has been investigated in the literature from two perspectives. One is to examine the relationship between the CDS and the bond markets in price discovery, and the other is concerned with researching the CDS trading effects on bond spreads. Referring to the former approach, most rel...

  8. Credit market shocks: evidence from corporate spreads and defaults

    OpenAIRE

    Roland Meeks

    2009-01-01

    Several recent papers have found that exogenous shocks to spreads paid in corporate credit markets are a substantial source of macroeconomic fluctuations. An alternative explanation of the data is that spreads respond endogenously to expectations of future default. We use a simple model of bond spreads to derive sign restrictions on the impulse-response functions of a VAR that identify credit shocks in the bond market, and compare them to results from a benchmark recursive VAR. We find that c...

  9. Techniques used on the credit derivatives market: credit default swaps.

    OpenAIRE

    Olléon-Assouan, E.

    2004-01-01

    As a response to the need for credit risk protection, the credit derivatives market has seen substantial growth over the past few years. While the deteriorating credit status of a large number of issuers in 2002 contributed to the expansion of this market, this growth can also be ascribed to the broadening of the uses to which these credit derivatives are put, above and beyond their original function of providing protection. This article describes how credit default swaps (CDSs) work and how ...

  10. Understanding Corporate Bond Spreads Using Credit Default Swaps

    OpenAIRE

    Alejandro Garcia; Jun Yang

    2009-01-01

    Corporate bond spreads worldwide have widened markedly since the beginning of the credit crisis in 2007. This article examines default and liquidity risk--the main components of the corporate bond spread--for Canadian firms that issue bonds in the U.S. market, focusing in particular on their evolution during the credit crisis. They find that, during this period, the liquidity component increased more for speculative-grade bonds than it did for investment-grade bonds, consistent with a "flight...

  11. Asset Pricing When Risk Sharing is Limited by Default

    OpenAIRE

    Fernando Alvarez; Urban J. Jermann

    2010-01-01

    We study the asset pricing implications of a multi-agent endowment economy where agents can default on contracts that would leave them otherwise worse off. We specialize and extend the environment studied by Kocherlakota (1995) and Kehoe and Levine (1993) to make it comparable to standard studies of asset pricing. We make contributions along two fronts. First, we extend the characterization of efficient allocations. Second, we present an equilibrium concept with complete markets and with endo...

  12. Comparing Australian and US Corporate Default Risk using Quantile Regression

    OpenAIRE

    Allen, David E.; Akhmad R. Kramadibrata; Powell, R. J.; Abhay Kumar Singh

    2011-01-01

    The severe bank stresses of the Global Financial Crisis (GFC) have underlined the importance of understanding and measuring extreme credit risk. The Australian economy is widely considered to have fared much better than the US and most other major world economies. This paper applies quantile regression and Monte Carlo simulation to the Merton structural credit model to investigate the impact of extreme asset value fluctuations on default probabilities of Australian companies in comparison to ...

  13. Decreased connectivity of the default mode network in pathological gambling: a resting state functional MRI study.

    Science.gov (United States)

    Jung, Myung Hun; Kim, Jae-Hun; Shin, Young-Chul; Jung, Wi Hoon; Jang, Joon Hwan; Choi, Jung-Seok; Kang, Do-Hyung; Yi, Jung-Seo; Choi, Chi-Hoon; Kwon, Jun Soo

    2014-11-01

    The default mode network (DMN) represents neuronal activity that is intrinsically generated during a resting state. The present study used resting-state fMRI to investigate whether functional connectivity is altered in pathological gambling (PG). Fifteen drug-naive male patients with PG and 15 age-matched male control subjects participated in the present study. The pathological gambling modification of the Yale-Brown Obsessive Compulsive Scale (PG-YBOCS), the Beck Depression Inventory, and the Beck Anxiety Inventory were used to determine symptom severity in all participants. Participants were instructed to keep their eyes closed and not to focus on any particular thoughts during the 4.68-min resting-state functional scan. The patients with PG displayed decreased default mode connectivity in the left superior frontal gyrus, right middle temporal gyrus, and precuneus compared with healthy controls. The severity of PG symptoms in patients with PG was negatively associated with connectivity between the posterior cingulate cortex seed region and the precuneus (r=-0.599, p=0.018). Decreased functional connectivity within DMN suggests that PG may share similar neurobiological abnormalities with other addictive disorders. Moreover, the severity of PG symptoms was correlated with decreased connectivity in the precuneus, which may be important in the response to treatment in patients with PG.

  14. Abnormal Default System Functioning in Depression: Implications for Emotion Regulation.

    Science.gov (United States)

    Messina, Irene; Bianco, Francesca; Cusinato, Maria; Calvo, Vincenzo; Sambin, Marco

    2016-01-01

    Depression is widely seen as the result of difficulties in regulating emotions. Based on neuroimaging studies on voluntary emotion regulation, neurobiological models have focused on the concept of cognitive control, considering emotion regulation as a shift toward involving controlled processes associated with activation of the prefrontal and parietal executive areas, instead of responding automatically to emotional stimuli. According to such models, the weaker executive area activation observed in depressed patients is attributable to a lack of cognitive control over negative emotions. Going beyond the concept of cognitive control, psychodynamic models describe the development of individuals' capacity to regulate their emotional states in mother-infant interactions during childhood, through the construction of the representation of the self, others, and relationships. In this mini-review, we link these psychodynamic models with recent findings regarding the abnormal functioning of the default system in depression. Consistently with psychodynamic models, psychological functions associated with the default system include self-related processing, semantic processes, and implicit forms of emotion regulation. The abnormal activation of the default system observed in depression may explain the dysfunctional aspects of emotion regulation typical of the condition, such as an exaggerated negative self-focus and rumination on self-esteem issues. We also discuss the clinical implications of these findings with reference to the therapeutic relationship as a key tool for revisiting impaired or distorted representations of the self and relational objects. PMID:27375536

  15. Default network deactivations are correlated with psychopathic personality traits.

    Directory of Open Access Journals (Sweden)

    Tong Sheng

    Full Text Available BACKGROUND: The posteromedial cortex (PMC and medial prefrontal cortex (mPFC are part of a network of brain regions that has been found to exhibit decreased activity during goal-oriented tasks. This network is thought to support a baseline of brain activity, and is commonly referred to as the "default network". Although recent reports suggest that the PMC and mPFC are associated with affective, social, and self-referential processes, the relationship between these default network components and personality traits, especially those pertaining to social context, is poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In the current investigation, we assessed the relationship between PMC and mPFC deactivations and psychopathic personality traits using fMRI and a self-report measure. We found that PMC deactivations predicted traits related to egocentricity and mPFC deactivations predicted traits related to decision-making. CONCLUSIONS/SIGNIFICANCE: These results suggest that the PMC and mPFC are associated with processes involving self-relevancy and affective decision-making, consistent with previous reports. More generally, these findings suggest a link between default network activity and personality traits.

  16. Market Microstructure Effects on Firm Default Risk Evaluation

    Directory of Open Access Journals (Sweden)

    Flavia Barsotti

    2016-07-01

    Full Text Available Default probability is a fundamental variable determining the credit worthiness of a firm and equity volatility estimation plays a key role in its evaluation. Assuming a structural credit risk modeling approach, we study the impact of choosing different non parametric equity volatility estimators on default probability evaluation, when market microstructure noise is considered. A general stochastic volatility framework with jumps for the underlying asset dynamics is defined inside a Merton-like structural model. To estimate the volatility risk component of a firm we use high-frequency equity data: market microstructure noise is introduced as a direct effect of observing noisy high-frequency equity prices. A Monte Carlo simulation analysis is conducted to (i test the performance of alternative non-parametric equity volatility estimators in their capability of filtering out the microstructure noise and backing out the true unobservable asset volatility; (ii study the effects of different non-parametric estimation techniques on default probability evaluation. The impact of the non-parametric volatility estimators on risk evaluation is not negligible: a sensitivity analysis defined for alternative values of the leverage parameter and average jumps size reveals that the characteristics of the dataset are crucial to determine which is the proper estimator to consider from a credit risk perspective.

  17. Abnormal Default System Functioning in Depression: Implications for Emotion Regulation

    Science.gov (United States)

    Messina, Irene; Bianco, Francesca; Cusinato, Maria; Calvo, Vincenzo; Sambin, Marco

    2016-01-01

    Depression is widely seen as the result of difficulties in regulating emotions. Based on neuroimaging studies on voluntary emotion regulation, neurobiological models have focused on the concept of cognitive control, considering emotion regulation as a shift toward involving controlled processes associated with activation of the prefrontal and parietal executive areas, instead of responding automatically to emotional stimuli. According to such models, the weaker executive area activation observed in depressed patients is attributable to a lack of cognitive control over negative emotions. Going beyond the concept of cognitive control, psychodynamic models describe the development of individuals’ capacity to regulate their emotional states in mother-infant interactions during childhood, through the construction of the representation of the self, others, and relationships. In this mini-review, we link these psychodynamic models with recent findings regarding the abnormal functioning of the default system in depression. Consistently with psychodynamic models, psychological functions associated with the default system include self-related processing, semantic processes, and implicit forms of emotion regulation. The abnormal activation of the default system observed in depression may explain the dysfunctional aspects of emotion regulation typical of the condition, such as an exaggerated negative self-focus and rumination on self-esteem issues. We also discuss the clinical implications of these findings with reference to the therapeutic relationship as a key tool for revisiting impaired or distorted representations of the self and relational objects. PMID:27375536

  18. Corporate Yield Spreads: Default Risk or Liquidity? New Evidence from the Credit-Default Swap Market, previously titled: "The Credit-Default Swap Market: Is Credit Protection Priced Correctly?"

    OpenAIRE

    Francis A. Longstaff; Mithal, Sanjay; Neis, Eric

    2004-01-01

    We use the information in credit-default swaps to obtain direct measures of the size of the default and nondefault components in corporate spreads. We find that the majority of the corporate spread is due to default risk. This result holds for all rating categories and is robust to the definition of the riskless curve. We also find that the nondefault component is time varying and strongly related to measures of bond-specific illiquidity as well as to macroeconomic measures of bond-market liq...

  19. Default risk sharing between banks and markets : the contribution of collateralized debt obligations

    OpenAIRE

    Franke, Günter; Krahnen, Jan Pieter

    2005-01-01

    This paper contributes to the economics of financial institutions risk management by exploring how loan securitization a.ects their default risk, their systematic risk, and their stock prices. In a typical CDO transaction a bank retains through a first loss piece a very high proportion of the expected default losses, and transfers only the extreme losses to other market participants. The size of the first loss piece is largely driven by the average default probability of the securitized asset...

  20. Definition and characterization of an extended social-affective default network

    OpenAIRE

    Amft, Maren; Bzdok, Danilo; Laird, Angela R.; Fox, Peter T.; Schilbach, Leonhard; Eickhoff, Simon B.

    2014-01-01

    Recent evidence suggests considerable overlap between the default mode network (DMN) and regions involved in social, affective and introspective processes. We considered these overlapping regions as the social-affective part of the default mode network. In this study we established a robust mapping of the underlying brain network formed by these regions and those strongly connected to them (the extended social-affective default network: eSAD). We first seeded meta-analytic connectivity modeli...

  1. MULTI-FACTOR APPROACH FOR PRICING BASKET CREDIT LINKED NOTES UNDER ISSUER DEFAULT RISK

    OpenAIRE

    Po-Cheng Wu

    2011-01-01

    This article proposes a multi-factor approach to incorporate issuer default risk into basket credit linked note (BCLN) pricing based on the Gaussian copula. The numerical analysis demonstrates that the issuer default risk increases the fair coupon rate. Contradicting the common belief that a positive default correlation between reference entities and an issuer increases the possibility of double losses and disfavors the BCLN holder, thereby driving up the BCLN coupon rate, analytical results ...

  2. 金融双语信用违约互换%Credit Default Swaps

    Institute of Scientific and Technical Information of China (English)

    刘超

    2007-01-01

    @@ Credit default swaps can be thought of as an insurance against the default of some underlying instrument1, or as a put option on the underlying instrument. In a typical credit default swap, as shown in figure, the party selling the credit risk (or the "protection buyer") makes periodic payments to the "protection seller" of a negotiated number of basis points , times the notional amount of the underlying bond or loan.

  3. Default probabilities and expected recovery: an analysis of emerging market sovereign bonds

    OpenAIRE

    Liz Dixon-Smith; Roman Goossens; Simon Hayes

    2005-01-01

    We develop a simple bond pricing model to map the prices of individual EME sovereign bonds into term structures of implied (risk-neutral) default probabilities and expected recovery rates. Simple indices of bond spreads are found to be closely correlated with long-term risk neutral default probabilities, so may provide a straightforward way of monitoring shifts in investors' perceptions. But short-term risk neutral default probabilities behave quite differently, implying that there are period...

  4. Default settings of computerized physician order entry system order sets drive ordering habits

    Directory of Open Access Journals (Sweden)

    Jordan Olson

    2015-01-01

    Full Text Available Background: Computerized physician order entry (CPOE systems are quickly becoming ubiquitous, and groups of orders ("order sets" to allow for easy order input are a common feature. This provides a streamlined mechanism to view, modify, and place groups of related orders. This often serves as an electronic equivalent of a specialty requisition. A characteristic, of these order sets is that specific orders can be predetermined to be "preselected" or "defaulted-on" whenever the order set is used while others are "optional" or "defaulted-off" (though there is typically the option is to "deselect" defaulted-on tests in a given situation. While it seems intuitive that the defaults in an order set are often accepted, additional study is required to understand the impact of these "default" settings in an order set on ordering habits. This study set out to quantify the effect of changing the default settings of an order set. Methods: For quality improvement purposes, order sets dealing with transfusions were recently reviewed and modified to improve monitoring of outcome. Initially, the order for posttransfusion hematocrits and platelet count had the default setting changed from "optional" to "preselected." The default settings for platelet count was later changed back to "optional," allowing for a natural experiment to study the effect of the default selections of an order set on clinician ordering habits. Results: Posttransfusion hematocrit values were ordered for 8.3% of red cell transfusions when the default order set selection was "off" and for 57.4% of transfusions when the default selection was "preselected" (P < 0.0001. Posttransfusion platelet counts were ordered for 7.0% of platelet transfusions when the initial default order set selection was "optional," increased to 59.4% when the default was changed to "preselected" (P < 0.0001, and then decreased to 7.5% when the default selection was returned to "optional." The posttransfusion platelet

  5. Valuing Credit Default Swap under a double exp onential jump diff usion model

    Institute of Scientific and Technical Information of China (English)

    YANG Rui-cheng; PANG Mao-xiu; JIN Zhuang

    2014-01-01

    This paper discusses the valuation of the Credit Default Swap based on a jump market, in which the asset price of a firm follows a double exponential jump diff usion process, the value of the debt is driven by a geometric Brownian motion, and the default barrier follows a continuous stochastic process. Using the Gaver-Stehfest algorithm and the non-arbitrage asset pricing theory, we give the default probability of the first passage time, and more, derive the price of the Credit Default Swap.

  6. Cognitive and emotional modulation of brain default operation.

    Science.gov (United States)

    Pallesen, Karen Johanne; Brattico, Elvira; Bailey, Christopher J; Korvenoja, Antti; Gjedde, Albert

    2009-06-01

    Goal-directed behavior lowers activity in brain areas that include the medial frontal cortex, the medial and lateral parietal cortex, and limbic and paralimbic brain regions, commonly referred to as the "default network." These activity decreases are believed to reflect the interruption of processes that are ongoing when the mind is in a restful state. Previously, the nature of these processes was probed by varying cognitive task parameters, but the presence of emotional processes, while often assumed, was little investigated. With fMRI, we studied the effect of systematic variations of both cognitive load and emotional stimulus connotation on task-related decreases in the default network by employing an auditory working memory (WM) task with musical sounds. The performance of the WM task, compared to passive listening, lowered the activity in medial and lateral, prefrontal, parietal, temporal, and limbic regions. In a subset of these regions, the magnitude of decrease depended on the memory load; the greater the cognitive load, the larger the magnitude of the observed decrease. Furthermore, in the right amygdala and the left precuneus, areas previously associated with processing of unpleasant dissonant musical sounds, there was an interaction between the experimental condition and the stimulus type. The current results are consistent with the previously reported effect of task difficulty on task-related brain activation decreases. The results also indicate that task-related decreases may be further modulated by the emotional stimulus connotation. PMID:18752396

  7. Default spacing is the optimal spacing for word reading.

    Science.gov (United States)

    van den Boer, Madelon; Hakvoort, Britt E

    2015-01-01

    Increased interletter spacing is thought to reduce crowding effects and to enhance fluent reading. Several studies have shown beneficial effects of increased interletter spacing on reading speed and accuracy, especially in poor readers. Therefore, increased interletter spacing appears to be a relatively easy way to enhance reading performance. However, in adult readers reading speed was shown to be impeded with increased interletter spacing. Thus, findings on interletter spacing are still inconclusive. In the current study we examined the effect of a range of interletter spacings (-0.5, default, 0.5, 1, 1.5, 2) on naming fluency of monosyllabic and bisyllabic words in beginning (Grade 2) and more advanced (Grade 4) readers. Additionally we tested the effects of spacing in a subsample of poor readers. In contrast to previous findings, neither beginning nor advanced readers benefited from an increase in interletter spacing. However, they did show reduced reading fluency when letter spacing was smaller than the default spacing, which may be indicative of a crowding effect. Poor readers showed a similar pattern. We conclude that an increase in interletter spacing has no effect on word naming fluency.

  8. Abnormal functional connectivity of default mode sub-networks in autism spectrum disorder patients.

    Science.gov (United States)

    Assaf, Michal; Jagannathan, Kanchana; Calhoun, Vince D; Miller, Laura; Stevens, Michael C; Sahl, Robert; O'Boyle, Jacqueline G; Schultz, Robert T; Pearlson, Godfrey D

    2010-10-15

    Autism spectrum disorders (ASDs) are characterized by deficits in social and communication processes. Recent data suggest that altered functional connectivity (FC), i.e. synchronous brain activity, might contribute to these deficits. Of specific interest is the FC integrity of the default mode network (DMN), a network active during passive resting states and cognitive processes related to social deficits seen in ASD, e.g. Theory of Mind. We investigated the role of altered FC of default mode sub-networks (DM-SNs) in 16 patients with high-functioning ASD compared to 16 matched healthy controls of short resting fMRI scans using independent component analysis (ICA). ICA is a multivariate data-driven approach that identifies temporally coherent networks, providing a natural measure of FC. Results show that compared to controls, patients showed decreased FC between the precuneus and medial prefrontal cortex/anterior cingulate cortex, DMN core areas, and other DM-SNs areas. FC magnitude in these regions inversely correlated with the severity of patients' social and communication deficits as measured by the Autism Diagnostic Observational Schedule and the Social Responsiveness Scale. Importantly, supplemental analyses suggest that these results were independent of treatment status. These results support the hypothesis that DM-SNs under-connectivity contributes to the core deficits seen in ASD. Moreover, these data provide further support for the use of data-driven analysis with resting-state data for illuminating neural systems that differ between groups. This approach seems especially well suited for populations where compliance with and performance of active tasks might be a challenge, as it requires minimal cooperation. PMID:20621638

  9. The single risk factor approach to capital charges in case of correlated loss given default rates

    OpenAIRE

    Dirk Tasche

    2004-01-01

    A new methodology for incorporating LGD correlation effects into the Basel II risk weight functions is introduced. This methodology is based on modelling of LGD and default event with a single loss variable. The resulting formulas for capital charges are numerically compared to the current proposals by the Basel Committee on Banking Supervision. Keywords: Regulatory capital charge, loss given default (LGD).

  10. 42 CFR 1001.1501 - Default of health education loan or scholarship obligations.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Default of health education loan or scholarship... Permissive Exclusions § 1001.1501 Default of health education loan or scholarship obligations. (a... obligations or loans in connection with health professions education made or secured in whole or in part...

  11. 5 CFR 185.110 - Default upon failure to file an answer.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Default upon failure to file an answer. 185.110 Section 185.110 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PROGRAM FRAUD CIVIL REMEDIES § 185.110 Default upon failure to file an answer. (a) If...

  12. 24 CFR 257.122 - Forgiveness or waiver of prepayment penalties and default fees.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Forgiveness or waiver of prepayment penalties and default fees. 257.122 Section 257.122 Housing and Urban Development Regulations Relating to... Procedures § 257.122 Forgiveness or waiver of prepayment penalties and default fees. The holder or...

  13. 75 FR 72660 - Extension of Temporary Exemptions for Eligible Credit Default Swaps To Facilitate Operation of...

    Science.gov (United States)

    2010-11-26

    ...We are extending the expiration dates in our temporary rules that provide exemptions under the Securities Act of 1933, the Securities Exchange Act of 1934, and the Trust Indenture Act of 1939 for certain credit default swaps in order to continue facilitating the operation of one or more central counterparties for those credit default swaps until the implementation of the clearing provisions of......

  14. Assessing Credit with Equity : A CEV Model with Jump to Default

    NARCIS (Netherlands)

    Campi, L.; Polbennikov, S.Y.; Sbuelz, A.

    2005-01-01

    Unlike in structural and reduced-form models, we use equity as a liquid and observable primitive to analytically value corporate bonds and credit default swaps.Restrictive assumptions on the .rm.s capital structure are avoided.Default is parsimoniously represented by equity value hitting the zero ba

  15. Strength of Default Mode Resting-State Connectivity Relates to White Matter Integrity in Children

    Science.gov (United States)

    Gordon, Evan M.; Lee, Philip S.; Maisog, Jose M.; Foss-Feig, Jennifer; Billington, Michael E.; VanMeter, John; Vaidya, Chandan J.

    2011-01-01

    A default mode network of brain regions is known to demonstrate coordinated activity during the resting state. While the default mode network is well characterized in adults, few investigations have focused upon its development. We scanned 9-13-year-old children with diffusion tensor imaging and resting-state functional magnetic resonance imaging.…

  16. 40 CFR 13.19 - Analysis of costs; automation; prevention of overpayments, delinquencies or defaults.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Analysis of costs; automation; prevention of overpayments, delinquencies or defaults. 13.19 Section 13.19 Protection of Environment...; automation; prevention of overpayments, delinquencies or defaults. (a) The Administrator may...

  17. 14 CFR 1261.413 - Analysis of costs; automation; prevention of overpayments, delinquencies, or defaults.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Analysis of costs; automation; prevention of overpayments, delinquencies, or defaults. 1261.413 Section 1261.413 Aeronautics and Space NATIONAL...) § 1261.413 Analysis of costs; automation; prevention of overpayments, delinquencies, or defaults....

  18. Altered effective connectivity within default mode network in major depression disorder

    Science.gov (United States)

    Li, Liang; Li, Baojuan; Bai, Yuanhan; Wang, Huaning; Zhang, Linchuan; Cui, Longbiao; Lu, Hongbing

    2016-03-01

    Understanding the neural basis of Major Depressive Disorder (MDD) is important for the diagnosis and treatment of this mental disorder. The default mode network (DMN) is considered to be highly involved in the MDD. To find directed interaction between DMN regions associated with the development of MDD, the effective connectivity within the DMN of the MDD patients and matched healthy controls was estimated by using a recently developed spectral dynamic causal modeling. Sixteen patients with MDD and sixteen matched healthy control subjects were included in this study. While the control group underwent the resting state fMRI scan just once, all patients underwent resting state fMRI scans before and after two months' treatment. The spectral dynamic causal modeling was used to estimate directed connections between four DMN nodes. Statistical analysis on connection strengths indicated that efferent connections from the medial frontal cortex (MFC) to posterior cingulate cortex (PCC) and to right parietal cortex (RPC) were significant higher in pretreatment MDD patients than those of the control group. After two-month treatment, the efferent connections from the MFC decreased significantly, while those from the left parietal cortex (LPC) to MFC, PCC and RPC showed a significant increase. These findings suggest that the MFC may play an important role for inhibitory conditioning of the DMN, which was disrupted in MDD patients. It also indicates that disrupted suppressive function of the MFC could be effectively restored after two-month treatment.

  19. Determinants of Banking Credit Default in Indonesia: A Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Muhammad Imaduddin

    2008-08-01

    Full Text Available This study aims to analyze the determinants of Islamic banking credit default compared with conventional banking in Indonesia. This study utilized timeseries analysis, by which ordinary least square method is adopted. 40 monthly data observations from January 2003 until April 2006 are used. The study is divided into two models, namely Islamic banking model and conventional banking model. The values of non-performing financing (NPF in Islamic banking and non-performing loan (NPL in conventional banking are treated as the dependent variables. The results showed that two-month lagged of non-performing financing (NPF, total asset (ASSET, the amount of thirdparty-funds (TPF, one-month lagged of total financing (DFIN, and growthof gross-domestic product (GDPG variables have significant impact to the ratio of non-performing financing (NPF in Islamic banking. Meanwhile, the three-month lagged of non-performing loan (DDDNPL, total asset (CASSET, three-month as well as two-month period lagged of total loan (DDDCRED and DDCRED, inter-bank money market (PUAB, and growth of gross-domestic (GDPG are significant to influence the ratio of non-performing loan (NPL in conventional banking. The result also implied that the general election in 2004 had a significant influence to the ratio of non-performing financing (NPF in Islamic banking.Even tough from the outset, it seems Islamic banking has a better performance than conventional banking by having a relatively low NPF, this study, however, has found the opposite. Albeit, Islamic banking showing a good long-runas well as short-run dynamics among all variables in the beginning, after modifying the model into autoregressive in the main analysis, results showed that conventional banking has a better performance than Islamic banking with higher correlation of determination. In this regard, we cannot assume thatIslamic banking is performing poorly in managing credit default problems. This is because the result

  20. 1034例利福平耐药结核杆菌对其它一线抗结核药物耐药性分布特征%Distribution characteristics of resistance to other first line anti-tuberculosis drugs among 1034 rifampin-resistant mycobacterium tuberculosis strains

    Institute of Scientific and Technical Information of China (English)

    谢贝; 苏雯婕; 刘志辉; 张言斌

    2011-01-01

    目的 了解广州市近17年来,结核分枝杆菌临床分离株利福平耐药情况及对其它一线抗结核药物的敏感性分布特征.方法 回顾性分析广州市胸科医院1992年2月-2008年7月期间门诊结核病人一线抗结核药物敏感性试验结果.结果 10 167例结核分支杆菌分离株中,耐R菌株1034例,耐H菌株2214例,耐S菌株1073例,耐E菌株622例,总体耐药率为25.80%;在1034例R耐药株中,H、R共同耐药者927例,占R耐药株总数的89.65%,却只占2214例H耐药株的41.87%;而R、S共同耐药者502例,R、E共同耐药者237例,分别占耐R株总数的48.55%及22.92%,明显少于R、H共同耐药者.结论 耐RFP菌株绝大部分同时对INH耐药,但反之不然,现有的耐药机制难以解释此种现象,结核杆菌是否存在其它耐药机制有待进一步研究.%Objective To explore rifampicin-resistant status of mycobacterium tuberculosis isolates in Guangzhou during the recent seventeen years, and their distribution characteristics of susceptibility to other first line anti-tuberculosis drugs. Methods The results of first line anti-tuberculosis drug susceptibility testing performed during the period of February 1992 to July 2008 in clinic patients were retrospectively analyzed. Results Of 10 167 mycobacterium tuberculosis isolates, 1034 were rifampin-resistant, 2214 isoniazid-resistant, 1073 streptomycinresistant, and 622 ethambutol-resistant; with a total drug resistance rate of 25.80%. Of 1034 rifampin-resistant isolates, 927 also developed isoniazid resistance, being 89.65% for the total number of rifampin-resistant isolates but only 41.87% for 2214 isoniazid-resistant isolates. Meanwhile, the number of rifampin- and streptomycin -resistant(502 strains)and rifampin- and ethambutol-resistant(237 strains)isolates was significantly smaller than that of rifampin- and isoniazid-resistant isolats. Conclusions Most of rifampin-resistant isolates also develop resistance to isoniazid, but not vice

  1. Regression And Time Series Analysis Of Loan Default At Minescho Cooperative Credit Union Tarkwa

    Directory of Open Access Journals (Sweden)

    Otoo

    2015-08-01

    Full Text Available Abstract Lending in the form of loans is a principal business activity for banks credit unions and other financial institutions. This forms a substantial amount of the banks assets. However when these loans are defaulted it tends to have serious effects on the financial institutions. This study sought to determine the trend and forecast loan default at Minescho CreditUnion Tarkwa. A secondary data from the Credit Union was analyzed using Regression Analysis and the Box-Jenkins method of Time Series. From the Regression Analysis there was a moderately strong relationship between the amount of loan default and time. Also the amount of loan default had an increasing trend. The two years forecast of the amount of loan default oscillated initially and remained constant from 2016 onwards.

  2. Optimal investment under multiple defaults risk: a BSDE-decomposition approach

    CERN Document Server

    Jiao, Ying; Pham, Huyên

    2011-01-01

    We study an optimal investment problem under contagion risk in a financial model subject to multiple jumps and defaults. The global market information is formulated as progressive enlargement of a default-free Brownian filtration, and the dependence of default times is modelled by a conditional density hypothesis. In this It\\^o-jump process model, we give a decomposition of the corresponding stochastic control problem into stochastic control problems in the default-free filtration, which are determined in a backward induction. The dynamic programming method leads to a backward recursive system of quadratic Backward Stochastic Differential Equations (BSDEs) in Brownian filtration, and our main result is to prove under fairly general conditions the existence and uniqueness of a solution to this system, which characterizes explicitly the value function and optimal strategies to the optimal investment problem. We illustrate our solutions approach with some numerical tests emphasizing the impact of default intensi...

  3. Top management turnover and firm default risk:Evidence from the Chinese securities market

    Institute of Scientific and Technical Information of China (English)

    Wei; Ting

    2011-01-01

    China has moved rapidly from a socialist planned economy to a market economy.As a result,many enterprises in China are seeking talented top management to increase their performance and decrease their default risk.Studies abound regarding top management turnover and its relationship with firm performance,however,few studies have connected top management turnover with firm default risk.In China,a market with extensive financial fraud,firm default risk is an important factor and thus we explore this relationship in the Chinese securities market.Our results indicate that firms with higher default risk are more likely to change their top management in the next financial reporting period.In addition,following changes in top management,such firms default less than other companies.

  4. The Role of Default Network Deactivation in Cognition and Disease

    Science.gov (United States)

    Anticevic, Alan; Cole, Michael W.; Murray, John D.; Corlett, Philip R.; Wang, Xiao-Jing; Krystal, John H.

    2012-01-01

    A considerable body of evidence has accumulated over recent years on the functions of the default-mode network (DMN) – a set of brain regions whose activity is high when the mind is not engaged in specific behavioral tasks and low during focused attention on the external environment. In this review, we focus on DMN suppression and its functional role in health and disease, summarizing evidence that spans several disciplines, including cognitive neuroscience, pharmacological neuroimaging, clinical neuroscience, and theoretical neuroscience. Collectively, this research highlights the functional relevance of DMN suppression for goal-directed cognition, possibly by reducing goal-irrelevant functions supported by the DMN (e.g., mind- wandering), and illustrates the functional significance of DMN suppression deficits in severe mental illness. PMID:23142417

  5. Empirical analysis of structural change in Credit Default Swap volatility

    International Nuclear Information System (INIS)

    The purpose of this paper is to study the structural change in Credit Default Swap volatility. We use statistical properties and a network approach to better understand the behavior of CDS volatility. We hypothesize that structural change occurs in CDS index during a financial crisis and it requires subperiod analysis, rather than full period analysis, to investigate properly. Our results show that the probability of large volatility is related to the structure of volatility but it is more significantly related to the size of volatility. Both the memory property and the size of volatility are confirmed to have dependence on the structure of volatility. The linked degree of CDS volatilities is highly related to the probability of large volatility and its predictability, regardless of structural change in volatility. Another interesting result is that the CDS volatility of a country is more related to the behavior of other volatilities, not the geographical location

  6. Is religious fundamentalism our default spirituality?: Implications for teacher education

    Directory of Open Access Journals (Sweden)

    Ferdinand J. Potgieter

    2014-02-01

    Full Text Available Using experiential interpretivism as underpinning methodology, this article investigates whether religious fundamentalism is the default spirituality of human beings. Our research is based on a hermeneutic reconstructive interpretation of religion, fundamentalism, radicalism, extremism, spirituality, life- and worldview, and the role of education in bringing about peaceful coexistence amongst people. We concluded that the natural religious-fundamentalist inclination of the human being tends to be (and needs to be counterbalanced by the education – that is, socialisation – that he or she receives from the moment of birth, the important first six or seven years of life, and throughout his or her life. Based on this conclusion, the article ends with the articulation of ten implications for teacher education.

  7. Cognitive and emotional modulation of brain default operation

    DEFF Research Database (Denmark)

    Pallesen, Karen Johanne; Brattico, Elvira; Bailey, Christopher J;

    2009-01-01

    of processes that are ongoing when the mind is in a restful state. Previously, the nature of these processes was probed by varying cognitive task parameters, but the presence of emotional processes, while often assumed, was little investigated. With fMRI, we studied the effect of systematic variations of both...... cognitive load and emotional stimulus connotation on task-related decreases in the default network by employing an auditory working memory (WM) task with musical sounds. The performance of the WM task, compared to passive listening, lowered the activity in medial and lateral, prefrontal, parietal, temporal......, and limbic regions. In a subset of these regions, the magnitude of decrease depended on the memory load; the greater the cognitive load, the larger the magnitude of the observed decrease. Furthermore, in the right amygdala and the left precuneus, areas previously associated with processing of unpleasant...

  8. The default mode network as a biomarker for monitoring the therapeutic effects of meditation.

    Science.gov (United States)

    Simon, Rozalyn; Engström, Maria

    2015-01-01

    The default mode network (DMN) is a group of anatomically separate regions in the brain found to have synchronized patterns of activation in functional magnetic resonance imaging (fMRI). Mentation associated with the DMN includes processes such as mind wandering, autobiographical memory, self-reflective thought, envisioning the future, and considering the perspective of others. Abnormalities in the DMN have been linked to symptom severity in a variety of mental disorders indicating that the DMN could be used as a biomarker for diagnosis. These correlations have also led to the use of DMN modulation as a biomarker for assessing pharmacological treatments. Concurrent research investigating the neural correlates of meditation, have associated DMN modulation with practice. Furthermore, meditative practice is increasingly understood to have a beneficial role in the treatment of mental disorders. Therefore we propose the use of DMN measures as a biomarker for monitoring the therapeutic effects of meditation practices in mental disorders. Recent findings support this perspective, and indicate the utility of DMN monitoring in understanding and developing meditative treatments for these debilitating conditions.

  9. The default mode network as a biomarker for monitoring the therapeutic effects of meditation

    Directory of Open Access Journals (Sweden)

    Rozalyn eSimon

    2015-06-01

    Full Text Available The default mode network (DMN is a group of anatomically separate regions in the brain found to have synchronized patterns of activation in functional magnetic resonance imaging (fMRI. Mentation associated with the DMN includes processes such as mind wandering, autobiographical memory, self-reflective thought, envisioning the future, and considering the perspective of others. Abnormalities in the DMN have been linked to symptom severity in a variety of mental disorders indicating that the DMN could be used as a biomarker for diagnosis. These correlations have also led to the use of DMN modulation as a biomarker for assessing pharmacological treatments. Concurrent research investigating the neurocorrelates of meditation have associated DMN modulation with practice. Furthermore, meditative practice is increasingly understood to have a beneficial role in the treatment of mental disorders. Therefore we propose the use of DMN measures as a biomarker for monitoring the therapeutic effects of meditation practices in mental disorders. Recent findings support this perspective, and indicate the utility of DMN monitoring in understanding and developing meditative treatments for these debilitating conditions.

  10. EMPIRICAL STUDY OF THE PROBABILITY OF DEFAULT IN CASE OF ROMANIAN COMPANIES LISTED ON STOCK EXCHANGE

    Directory of Open Access Journals (Sweden)

    Marton Noemi, Racz Timea Erzsebet

    2011-07-01

    Full Text Available The importance of estimation of a firm's probability of default increased significantly during the economic and financial crisis for financial institutions, which can be explained by the fact that the share of nonperforming loans increased in this period. The probability of default can be estimated with structural models, which have on base the methodology developed by Merton (1974, methodology used by Moody's Corporation (known as KMV Merton model. The aim of this study is to estimate the probability of default of companies listed on Bucharest Stock Exchange using this methodology. This approach was widely used in the literature by many researchers (i.e., Kealhofer and Kurbat (2000, Crosbie and Bohn (2002, Duffie and Wang (2004, Bharath and Shumway (2004, 2008. In Romania this methodology was empirically tested by Codirlaşu (2007, who estimated using Merton's methodology the probability of default of companies listed on the Bucharest Stock Exchange, respectively by Bobircă et al. (2008, where the probabilities of default were estimated in case of 42 companies listed on the Bucharest Stock Exchange for 2000-2008 time period. In this paper we used Merton's model, which assumes that a company defaults if the value of its assets is less than the promised dept repayment at time T. The process of estimating the probability of default starts from the following firm specific variables: the market value of the firm's assets, the share prices, the value of the liabilities and the risk-free rate. The analyzed period is 2003-2010, containing the economic and financial crisis period, too. Analyzing the financial statements of the companies listed on the Bucharest Stock Exchange, we determined the input parameters of the model and calculated the quarterly probabilities of default of each analyzed company. According to our results the probabilities of default have a reduced value in the majority of the cases.

  11. O Caso default no português do Brasil: revisitando o Caso dos inacusativos

    Directory of Open Access Journals (Sweden)

    Evani Viotti

    2012-11-01

    Full Text Available The goal of this paper is to investigate the contexts in BrazilianPortuguese in which DPs are marked with nominative default Case,and to analyse the possibility of attributing default Case to the DPsin post-verbal position of sentences built with inaccusative verbs.The claim is that, if the verb shows agreement features, such DPswill check the nominative Case in the syntax; if the verb isuninflected for person and number, such DPs will receive a defaultCase marking in the morphological component.

  12. Global guidelines for treatment of tuberculosis among persons living with HIV: unresolved issues.

    Science.gov (United States)

    Kumar, A; Kumar, A M V; Gupta, D; Kanchar, A; Mohammed, S; Srinath, S; Tripathy, S; Rajasekaran, S; Chan, P-L; Swaminathan, S; Dewan, P K

    2012-05-01

    The Revised National Tuberculosis Control Programme (RNTCP) in India uses a fully intermittent thrice-weekly rifampicin-containing regimen for all tuberculosis (TB) patients, including those who are human immunodeficiency virus (HIV) infected, whereas the World Health Organization (WHO) recommends daily anti-tuberculosis treatment at least during the intensive phase. The WHO recommendation was based on the results of a meta-analysis demonstrating increased risk of recurrence and failure among HIV-infected TB patients receiving intermittent TB treatment compared to a daily regimen. Review of the primary evidence indicates limited, low-quality information on intermittency, mostly from observational studies in the pre-antiretroviral treatment (ART) era. Molecular epidemiology in India indicates that most of the recurrences and many of the failures result from exogenous re-infection, suggesting poor infection control and high transmission rather than poor regimen efficacy. Subsequently published studies have shown acceptable treatment outcomes among HIV-infected TB patients receiving intermittent anti-tuberculosis regimens with concomitant ART. Treatment outcomes among HIV-infected TB patients treated under programmatic conditions show low failure rates but high case fatality; death has been associated with lack of ART. The highest priority is therefore to reduce mortality by linking all HIV-infected TB patients to ART. While urgently seeking to reduce death rates among HIV-infected TB patients, given the poor evidence for change and operational advantages of an intermittent regimen, the RNTCP intends to collect the necessary evidence to inform national policy decisions through randomised clinical trials. PMID:22507931

  13. Benchmark Simulation Model No 2: finalisation of plant layout and default control strategy.

    Science.gov (United States)

    Nopens, I; Benedetti, L; Jeppsson, U; Pons, M-N; Alex, J; Copp, J B; Gernaey, K V; Rosen, C; Steyer, J-P; Vanrolleghem, P A

    2010-01-01

    The COST/IWA Benchmark Simulation Model No 1 (BSM1) has been available for almost a decade. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the research work related to the benchmark simulation models has resulted in more than 300 publications worldwide demonstrates the interest in and need of such tools within the research community. Recent efforts within the IWA Task Group on "Benchmarking of control strategies for WWTPs" have focused on an extension of the benchmark simulation model. This extension aims at facilitating control strategy development and performance evaluation at a plant-wide level and, consequently, includes both pretreatment of wastewater as well as the processes describing sludge treatment. The motivation for the extension is the increasing interest and need to operate and control wastewater treatment systems not only at an individual process level but also on a plant-wide basis. To facilitate the changes, the evaluation period has been extended to one year. A prolonged evaluation period allows for long-term control strategies to be assessed and enables the use of control handles that cannot be evaluated in a realistic fashion in the one week BSM1 evaluation period. In this paper, the finalised plant layout is summarised and, as was done for BSM1, a default control strategy is proposed. A demonstration of how BSM2 can be used to evaluate control strategies is also given. PMID:21045320

  14. Comparison of the safety and efficacy of a fixed-dose combination regimen and separate formulations for pulmonary tuberculosis treatment

    Directory of Open Access Journals (Sweden)

    Jiun-Ting Wu

    2015-06-01

    Full Text Available OBJECTIVES: Fixed-dose combination formulations, which simplify the administration of drugs and prevent the development of drug resistance, have been recommended as a standard anti-tuberculosis treatment regimen. However, the composition and dosage recommendations for fixed-dose combination formulations differ from those for separate formulations. Thus, questions about the effectiveness and side effects of combination formulations remain. The aim of this study was to compare the safety and efficacy of these two types of anti-tuberculosis regimens for pulmonary tuberculosis treatment. METHOD: A prospective, randomized controlled study was conducted using the directly observed treatment short-course strategy. Patients were randomly allocated to one of two short-course regimens. One year after completing the treatment, these patients’ outcomes were analyzed. ClinicalTrials.gov: NCT00979290. RESULTS: A total of 161 patients were enrolled, 142 of whom were evaluable for safety assessment. The two regimens had a similar incidence of adverse effects. In the per-protocol population, serum bilirubin concentrations at the peak level, at week 4, and at week 8 were significantly higher for the fixed-dose combination formulation than for the separate formulations. All patients had negative sputum cultures at the end of the treatment, and no relapse occurred after one year of follow-up. CONCLUSIONS: In this randomized study, transient higher serum bilirubin levels were noted for the fixed-dose combination regimen compared with the separate formulations during treatment. However, no significant difference in safety or efficacy was found between the groups when the directly observed treatment short-course strategy was used.

  15. Default network connectivity decodes brain states with simulated microgravity.

    Science.gov (United States)

    Zeng, Ling-Li; Liao, Yang; Zhou, Zongtan; Shen, Hui; Liu, Yadong; Liu, Xufeng; Hu, Dewen

    2016-04-01

    With great progress of space navigation technology, it becomes possible to travel beyond Earth's gravity. So far, it remains unclear whether the human brain can function normally within an environment of microgravity and confinement. Particularly, it is a challenge to figure out some neuroimaging-based markers for rapid screening diagnosis of disrupted brain function in microgravity environment. In this study, a 7-day -6° head down tilt bed rest experiment was used to simulate the microgravity, and twenty healthy male participants underwent resting-state functional magnetic resonance imaging scans at baseline and after the simulated microgravity experiment. We used a multivariate pattern analysis approach to distinguish the brain states with simulated microgravity from normal gravity based on the functional connectivity within the default network, resulting in an accuracy of no less than 85 % via cross-validation. Moreover, most discriminative functional connections were mainly located between the limbic system and cortical areas and were enhanced after simulated microgravity, implying a self-adaption or compensatory enhancement to fulfill the need of complex demand in spatial navigation and motor control functions in microgravity environment. Overall, the findings suggest that the brain states in microgravity are likely different from those in normal gravity and that brain connectome could act as a biomarker to indicate the brain state in microgravity. PMID:27066149

  16. Gamification of learning deactivates the Default Mode Network

    Directory of Open Access Journals (Sweden)

    Paul Alexander Howard-Jones

    2016-01-01

    Full Text Available We hypothesised that embedding educational learning in a game would improve learning outcomes, with increased engagement and recruitment of cognitive resources evidenced by increased activation of working memory network (WMN and deactivation of Default Mode Network (DMN regions. In an fMRI study, we compared activity during periods of learning in three conditions that were increasingly game-like: Study-only (when periods of learning were followed by an exemplar question together with its correct answer, Self-quizzing (when periods of learning were followed by a multiple choice question in return for a fixed number of points and Game-based (when, following each period of learning, participants competed with a peer to answer the question for escalating, uncertain rewards. DMN hubs deactivated as conditions became more game-like, alongside greater self-reported engagement and, in the Game-based condition, higher learning scores. These changes did not occur with any detectable increase in WMN activity. Additionally, ventral striatal activation was associated with responding to questions and receiving positive question feedback. Results support the significance of DMN deactivation for educational learning, and are aligned with recent evidence suggesting DMN and WMN activity may not always be anti-correlated.

  17. Gamification of Learning Deactivates the Default Mode Network.

    Science.gov (United States)

    Howard-Jones, Paul A; Jay, Tim; Mason, Alice; Jones, Harvey

    2015-01-01

    We hypothesized that embedding educational learning in a game would improve learning outcomes, with increased engagement and recruitment of cognitive resources evidenced by increased activation of working memory network (WMN) and deactivation of default mode network (DMN) regions. In an fMRI study, we compared activity during periods of learning in three conditions that were increasingly game-like: Study-only (when periods of learning were followed by an exemplar question together with its correct answer), Self-quizzing (when periods of learning were followed by a multiple choice question in return for a fixed number of points) and Game-based (when, following each period of learning, participants competed with a peer to answer the question for escalating, uncertain rewards). DMN hubs deactivated as conditions became more game-like, alongside greater self-reported engagement and, in the Game-based condition, higher learning scores. These changes did not occur with any detectable increase in WMN activity. Additionally, ventral striatal activation was associated with responding to questions and receiving positive question feedback. Results support the significance of DMN deactivation for educational learning, and are aligned with recent evidence suggesting DMN and WMN activity may not always be anti-correlated. PMID:26779054

  18. Damage to the default mode network disrupts autobiographical memory retrieval.

    Science.gov (United States)

    Philippi, Carissa L; Tranel, Daniel; Duff, Melissa; Rudrauf, David

    2015-03-01

    Functional neuroimaging studies have implicated the default mode network (DMN) in autobiographical memory (AM). Convergent evidence from a lesion approach would help clarify the role of the DMN in AM. In this study, we used a voxelwise lesion-deficit approach to test the hypothesis that regions of the DMN are necessary for AM. We also explored whether the neural correlates of semantic AM (SAM) and episodic AM (EAM) were overlapping or distinct. Using the Iowa Autobiographical Memory Questionnaire, we tested AM retrieval in 92 patients with focal, stable brain lesions. In support of our hypothesis, damage to regions within the DMN (medial prefrontal cortex, mPFC; posterior cingulate cortex, PCC; inferior parietal lobule, IPL; medial temporal lobe, MTL) was associated with AM impairments. Within areas of effective lesion coverage, the neural correlates of SAM and EAM were largely distinct, with limited areas of overlap in right IPL. Whereas SAM deficits were associated with left mPFC and MTL damage, EAM deficits were associated with right mPFC and MTL damage. These results provide novel neuropsychological evidence for the necessary role of parts of the DMN in AM. More broadly, the findings shed new light on how the DMN participates in self-referential processing.

  19. Platelet serotonin transporter function predicts default-mode network activity.

    Directory of Open Access Journals (Sweden)

    Christian Scharinger

    Full Text Available The serotonin transporter (5-HTT is abundantly expressed in humans by the serotonin transporter gene SLC6A4 and removes serotonin (5-HT from extracellular space. A blood-brain relationship between platelet and synaptosomal 5-HT reuptake has been suggested, but it is unknown today, if platelet 5-HT uptake can predict neural activation of human brain networks that are known to be under serotonergic influence.A functional magnetic resonance study was performed in 48 healthy subjects and maximal 5-HT uptake velocity (Vmax was assessed in blood platelets. We used a mixed-effects multilevel analysis technique (MEMA to test for linear relationships between whole-brain, blood-oxygen-level dependent (BOLD activity and platelet Vmax.The present study demonstrates that increases in platelet Vmax significantly predict default-mode network (DMN suppression in healthy subjects independent of genetic variation within SLC6A4. Furthermore, functional connectivity analyses indicate that platelet Vmax is related to global DMN activation and not intrinsic DMN connectivity.This study provides evidence that platelet Vmax predicts global DMN activation changes in healthy subjects. Given previous reports on platelet-synaptosomal Vmax coupling, results further suggest an important role of neuronal 5-HT reuptake in DMN regulation.

  20. Altered default mode network functional connectivity in schizotypal personality disorder.

    Science.gov (United States)

    Zhang, Qing; Shen, Jing; Wu, Jianlin; Yu, Xiao; Lou, Wutao; Fan, Hongyu; Shi, Lin; Wang, Defeng

    2014-12-01

    The default mode network (DMN) has been identified to play a critical role in many mental disorders, but such abnormalities have not yet been determined in patients with schizotypal personality disorder (SPD). The purpose of this study was to analyze the alteration of the DMN functional connectivity in subjects with (SPD) and compared it to healthy control subjects. Eighteen DSM-IV diagnosed SPD subjects (all male, average age: 19.7±0.9) from a pool of 3000 first year college students, and eighteen age and gender matched healthy control subjects were recruited (all male, average age: 20.3±0.9). Independent component analysis (ICA) was used to analyze the DMN functional connectivity alteration. Compared to the healthy control group, SPD subjects had significantly decreased functional connectivity in the frontal areas, including the superior and medial frontal gyrus, and greater functional connectivity in the bilateral superior temporal gyrus and sub-lobar regions, including the bilateral putamen and caudate. Compared to subjects with SPD, the healthy control group showed decreased functional connectivity in the bilateral posterior cingulate gyrus, but showed greater functional connectivity in the right transverse temporal gyrus and left middle temporal gyrus. The healthy control group also showed greater activation in the cerebellum compared to the SPD group. These findings suggest that DMN functional connectivity, particularly that involving cognitive or emotional regulation, is altered in SPD subjects, and thus may be helpful in studying schizophrenia.

  1. Prediction of default probability in banking industry using CAMELS index: A case study of Iranian banks

    Directory of Open Access Journals (Sweden)

    Mohammad Khodaei Valahzaghard

    2013-04-01

    Full Text Available This study examines the relationship between CAMELS index and default probability among 20 Iranian banks. The proposed study gathers the necessary information from their financial statements over the period 2005-2011. The study uses logistic regression along with Pearson correlation analysis to consider the relationship between default probability and six independent variables including capital adequacy, asset quality, management quality, earning quality, liquidity quality and sensitivity of market risk. The results indicate that there were no meaningful relationship between default probability and three independent variables including capital adequacy, asset quality and sensitivity of market risk. However, the results of our statistical tests support such relationship between default probability and three other variables including management quality, earning quality and liquidity quality.

  2. 75 FR 26904 - Mandatory Reporting of Greenhouse Gases: Notice of Data Availability; Default Emission Factors...

    Science.gov (United States)

    2010-05-13

    ... Emission Factors for Semiconductor Manufacturing Refined Process Categories AGENCY: Environmental... Protection Agency (EPA) is making available to the public draft default emission factors for semiconductor... of Greenhouse Gases: Additional Sources of Fluorinated GHGs (75 FR 18652) which included...

  3. Abnormal functional connectivity of default mode sub-networks in autism spectrum disorder patients

    OpenAIRE

    Assaf, Michal; Jagannathan, Kanchana; Calhoun, Vince D.; Miller, Laura; Stevens, Michael C.; Sahl, Robert; O'Boyle, Jacqueline G.; Schultz, Robert T.; Godfrey D. Pearlson

    2010-01-01

    Autism spectrum disorders (ASDs) are characterized by deficits in social and communication processes. Recent data suggest that altered functional connectivity (FC), i.e. synchronous brain activity, might contribute to these deficits. Of specific interest is the FC integrity of the default mode network (DMN), a network active during passive resting states and cognitive processes related to social deficits seen in ASD, e.g. Theory of Mind. We investigated the role of altered FC of default mode ...

  4. 34 CFR 33.10 - Default upon failure to file an answer.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Default upon failure to file an answer. 33.10 Section 33.10 Education Office of the Secretary, Department of Education PROGRAM FRAUD CIVIL REMEDIES ACT § 33.10 Default upon failure to file an answer. (a) If the defendant does not file an answer within the time prescribed in § 33.9(a), the...

  5. Predicting default of a small business using different definitions of financial distress

    OpenAIRE

    S-M Lin; Ansell, J; G Andreeva

    2012-01-01

    The paper introduces a number of risk-rating models for UK small businesses applying an accounting-based approach, which uses financial ratios to predict corporate bankruptcy. An enhancement to these models is considered through features typical to retail credit risk modelling. A common problem of default prediction consists in the relatively small number of bankruptcies or real defaults available for model-building. In order to expand the ‘default’ group beyond bankrupt companies, the paper ...

  6. Overpricing in Emerging Market Credit-Default-Swap Contracts; Some Evidence from Recent Distress Cases

    OpenAIRE

    Jochen R. Andritzky; Manmohan Singh

    2005-01-01

    Since recent debt restructurings that constitute credit events have been more frequent than outright defaults, sovereign bond prices may not collapse during distress. In this case, the likely high recovery values after restructuring suggest that the cost of credit-default-swap (CDS) contracts to the buyer (as measured by CDS spreads) may be higher than warranted. We estimate the extent of such overpricing by using the cheapest-to-deliver (CTD) bond as a proxy for the recovery-value assumption.

  7. Do corporate bond and credit default swap markets value environmental, social or corporate governance events?

    OpenAIRE

    Berg, Florian; Le Pen, Yannick

    2013-01-01

    We measure the impact of negative environmental, social and governance news on corporate bond prices and credit default swap premiums for the Eurozone market. Each firm is affected at least by one piece of news related to its environmental, social and governance practices. Each news is then flagged with an indicator of importance. Ab- normal bond returns are computed by subtracting return from a matching portfolio to the return of the observed bond return. Abnormal credit default swap return ...

  8. Default and Renegotiation of Latin American Foreign Bonds in the Interwar Period

    OpenAIRE

    Erika Jorgensen; Jeffrey Sachs

    1988-01-01

    This paper examines the patterns of defaults, renegotiations, and final settlements on foreign borrowing of several Latin American governments in the interwar period. One goal of the paper is to provide a detailed historical account of the borrowing and renegotiation experience of five Latin borrowers (Argentina, Bolivia, Chile, Colombia, and Peru). Another goal is to provide a quantitative assessment of the amount of debt relief that was implicit in the negotiated settlements of the defaults...

  9. Validation of the Merton Distance to the Default Model under Ambiguity

    Directory of Open Access Journals (Sweden)

    Wei-ling Chen

    2014-03-01

    Full Text Available Bharath and Shumway (2008 provide evidence that shows that it is the functional form of Merton’s (1974 distance to default (DD model that makes it useful and important for predicting defaults. In this paper, we investigate whether the default predictability of the Merton DD model would be affected by taking investors’ ambiguity aversion into consideration. The Cox proportional hazard model is used to compare the forecasting power of Bharath and Shumway’s naive model, which retains the functional form of the Merton DD model and computes the default probability in a naive way, with our new model, which treats investors’ ambiguity aversion as additional information. We provide evidence to show that our new model performs better than Bharath and Shumway’s naive model. In addition, our empirical results show that the statistical significance of Bharath and Shumway’s naive default probability is retained in the credit default swap (CDS spread regressions, though the sign of the coefficient is changed. However, both the sign and the statistical significance of our model are retained in the CDS spread regressions.

  10. Impaired default network functional connectivity in autosomal dominant Alzheimer disease

    Science.gov (United States)

    Chhatwal, Jasmeer P.; Schultz, Aaron P.; Johnson, Keith; Benzinger, Tammie L.S.; Jack, Clifford; Ances, Beau M.; Sullivan, Caroline A.; Salloway, Stephen P.; Ringman, John M.; Koeppe, Robert A.; Marcus, Daniel S.; Thompson, Paul; Saykin, Andrew J.; Correia, Stephen; Schofield, Peter R.; Rowe, Christopher C.; Fox, Nick C.; Brickman, Adam M.; Mayeux, Richard; McDade, Eric; Bateman, Randall; Fagan, Anne M.; Goate, Allison M.; Xiong, Chengjie; Buckles, Virginia D.; Morris, John C.

    2013-01-01

    Objective: To investigate default mode network (DMN) functional connectivity MRI (fcMRI) in a large cross-sectional cohort of subjects from families harboring pathogenic presenilin-1 (PSEN1), presenilin-2 (PSEN2), and amyloid precursor protein (APP) mutations participating in the Dominantly Inherited Alzheimer Network. Methods: Eighty-three mutation carriers and 37 asymptomatic noncarriers from the same families underwent fMRI during resting state at 8 centers in the United States, United Kingdom, and Australia. Using group-independent component analysis, fcMRI was compared using mutation status and Clinical Dementia Rating to stratify groups, and related to each participant's estimated years from expected symptom onset (eYO). Results: We observed significantly decreased DMN fcMRI in mutation carriers with increasing Clinical Dementia Rating, most evident in the precuneus/posterior cingulate and parietal cortices (p < 0.001). Comparison of asymptomatic mutation carriers with noncarriers demonstrated decreased fcMRI in the precuneus/posterior cingulate (p = 0.014) and right parietal cortex (p = 0.0016). We observed a significant interaction between mutation carrier status and eYO, with decreases in DMN fcMRI observed as mutation carriers approached and surpassed their eYO. Conclusion: Functional disruption of the DMN occurs early in the course of autosomal dominant Alzheimer disease, beginning before clinically evident symptoms, and worsening with increased impairment. These findings suggest that DMN fcMRI may prove useful as a biomarker across a wide spectrum of disease, and support the feasibility of DMN fcMRI as a secondary endpoint in upcoming multicenter clinical trials in Alzheimer disease. PMID:23884042

  11. 治疗剂量下4种抗结核药物与Caco-2细胞上P-gp相互作用研究%Initial Study on Interaction between Therapeutic Doses of Four Anti-Tuberculosis Drugs and P-Glycoprotein in Caco-2 Cells

    Institute of Scientific and Technical Information of China (English)

    方平飞; 高维; 李焕德; 刘艺平

    2011-01-01

    目的 研究治疗剂量下4种抗结核药物(异烟肼、左氧氟沙星、乙胺丁醇、吡嗪酰胺)对Caco-2细胞上P-糖蛋白功能、表达及MDR1 mRNA表达的影响,从而解释联合抗痨治疗中不同组合的合理性.方法 采用流式细胞仪测定细胞内罗丹明-123的浓度,考察药物对P-糖蛋白功能的影响,流式细胞术分析药物对Caco-2细胞上P-糖蛋白表达的影响,实时荧光定量PCR技术分析药物对Caco-2细胞MDRI基因mRNA水平表达的影响.结果 含药培养20 d后,异烟肼和乙胺丁醇减少了罗丹明-123在Caco-2细胞内的蓄积(P<0.05),为诱导作用;异烟肼、乙胺丁醇均上调了Caco-2细胞上P-糖蛋白的表达(P<0.05),其P-糖蛋白表达量分别为阴性对照组的3.5和3.8倍;同时上调了Caco-2细胞上MDR1 mRNA的表达(P<0.05),其MDRImRNA的表达量分别为阴性对照组的11.5和11倍.左氧氟沙星增加了罗丹明-123在Caco-2细胞内的蓄积(P<0.05),为抑制作用;下调了Caco-2细胞上P-糖蛋白和MDR1 mRNA的表达(P<0.05),其P-糖蛋白和MDR1 mRNA表达量分别为阴性对照组的50%和32%.而吡嗪酰胺与P-糖蛋白无明显相互作用.结论 治疗剂量的异烟肼和乙胺丁醇为P-糖蛋白的诱导剂,左氧氟沙星为P-糖蛋白的抑制剂,而吡嗪酰胺对P-糖蛋白功能和表达无明显影响.%OBJECTIVE To study the effects of four anti-tuberculosis drugs on the function and expression of P-glycoprotein and the MDR1 mRNA expression, for explaining the rationality of different combination in anti-tuberculosis chemotherapy. METHODS The effect of the drugs on P-glycoprotein function was analyzed using Rh-123 assay. The flow cytometry was used to determine the intracellular Rh-123 concentration and the expression of P-glycoprotein in Caco-2 cells. Real-time fluorescent quantitative polymerase chain reaction was used to measure the expression of MDR1 gene mRNA in Caco-2 cells. RESULTS After the intervention for 20 d, the

  12. 违约相关性下包含信用债券的最优投资组合%Optimal portfolio with defaultable bonds under default correlation

    Institute of Scientific and Technical Information of China (English)

    卞世博; 刘海龙

    2013-01-01

    This paper researched a representative investor how to optimally allocate her wealth among the following securities: defaultable bonds portfolio, stock (stock index) and a bank account, when there is default correlation. Modeled the default correlation through a reduced-form model and solved the dynamics of assets price. Using stochastic control method, obtained a closed-form solution to this optimal problem. Bringing default correlation into investment portfolio and revealing its influence to optimal portfolio are key distinguishing features.%研究了当信用债券之间的违约存在相关性时,投资者配置于信用债券组合、股票(股指)和银行存款的最优投资组合问题.利用简约化模型来刻画信用债券之间的违约相关性,并推导出各资产价格的动态方程,通过随机控制方法给出了此优化问题的解析解,将违约相关性引入至投资组合并揭示了其对最优投资组合的影响是本文与以往文献的显著不同和主要创新.

  13. Evaluation of Hepatoprotective Effect of Silymarin Among Under Treatment Tuberculosis Patients: A Randomized Clinical Trial.

    Science.gov (United States)

    Marjani, Majid; Baghaei, Parvaneh; Kazempour Dizaji, Mehdi; Gorji Bayani, Pegah; Fahimi, Fanak; Tabarsi, Payam; Velayati, Ali Akbar

    2016-01-01

    Hepatic toxicity is the most serious adverse effect of anti-tuberculosis drugs. This study was performed to evaluate the efficacy of silymarin as a hepatoprotective herbal agent. In a randomized double blind clinical trial, 70 new cases of pulmonary tuberculosis were divided into two groups. The intervention group was assigned to receive silymarin and the control group received placebo. Tuberculosis was treated by classic regimen consisting isoniazid, rifampin, pyrazinamide and ethambutol. No statistically significant difference was found between the two groups concerning the frequency of drug induced liver injury or mild elevation of liver enzymes. Silymarin was safe without any major side effect. Our results showed no significant hepatoprotective effect of silymarin among patients on tuberculosis treatment. PMID:27610165

  14. Anti-tuberculosis Cycloartane Triterpenoids from Radermachera boniana

    Science.gov (United States)

    Truong, Ngan B.; Pham, Cuong V.; Doan, Huong T. M.; Nguyen, Hung V.; Nguyen, Cuong M.; Nguyen, Hiep T.; Zhang, Hong-jie; Fong, Harry H. S.; Franzblau, Scott G.; Soejarto, Djaja D.; Chau, Minh V.

    2013-01-01

    Three new triterpenoids, bonianic acids A (1), and B (2) and 3-O-acetyluncaric acid (3) were isolated from the leaves and twigs of Radermachera boniana (Bignoniaceae), together with six known compounds ursolic acid (4), oleanolic acid (5), 3-epi-oleanolic acid (6), 3α-O-acetyl-α-boswellic acid (7), ergosterol peroxide (8), and β-sitostenone (9). Ergosterol peroxide (8), bonianic acids A (1) and B (2) exhibited significant activity against Mycobacterium tuberculosis H37Rv strain. PMID:21469696

  15. Measurement, Monitoring, and Forecasting of Consumer Credit Default Risk - An Indicator Approach Based on Individual Payment Histories

    OpenAIRE

    Schwarz, Alexandra

    2011-01-01

    The statistical techniques which cover the process of modeling and evaluating consumer credit risk have become widely accepted instruments in risk management. In contrast, we find only few and vague statements on how to define the default event, i. e. on the concrete circumstances that lead to the decision of identifying a certain credit as defaulted. Based on a unique data set of individual payment histories this paper proposes a definition of default which is based on the time due amounts a...

  16. Assessing Credit Default using Logistic Regression and Multiple Discriminant Analysis: Empirical Evidence from Bosnia and Herzegovina

    Directory of Open Access Journals (Sweden)

    Deni Memić

    2015-01-01

    Full Text Available This article has an aim to assess credit default prediction on the banking market in Bosnia and Herzegovina nationwide as well as on its constitutional entities (Federation of Bosnia and Herzegovina and Republika Srpska. Ability to classify companies info different predefined groups or finding an appropriate tool which would replace human assessment in classifying companies into good and bad buckets has been one of the main interests on risk management researchers for a long time. We investigated the possibility and accuracy of default prediction using traditional statistical methods logistic regression (logit and multiple discriminant analysis (MDA and compared their predictive abilities. The results show that the created models have high predictive ability. For logit models, some variables are more influential on the default prediction than the others. Return on assets (ROA is statistically significant in all four periods prior to default, having very high regression coefficients, or high impact on the model's ability to predict default. Similar results are obtained for MDA models. It is also found that predictive ability differs between logistic regression and multiple discriminant analysis.

  17. Framework of pricing a revolver loan in the case of dependent defaults

    Institute of Scientific and Technical Information of China (English)

    ZHAN Yuan-rui; YAO Xiang-hua; ZHANG Xue-yu

    2006-01-01

    In this paper we analyze the main characteristics of correlative clients and the revolver loan and reduced form models for the correlative clients A and B in real-life. This is done by decomposing the default intensity into specific default intensity and homogenous default intensity. We also use a mathematical formula of the default joint distribution function and the marginal distribution function in the physical measure to deduce the martingale measure. The modeling idea on pricing the revolver loan with client A is presented by applying reduced form model. Through calculating the cost and income fund flows under the martingale measure, the framework of a "break-even" pricing model is established. The conclusion is that the interest rate of a revolver loan for client A on the "break-even" point is not related to the maximum authorized amount and the drawdown amount at that time under some assumptions, but only rests with credit rating and homogenous default intensity of client A and B as well as loan term of client A.

  18. Towards an Understanding of the Effects of IFRS Adoption on Credit Default Swap Contracts

    Directory of Open Access Journals (Sweden)

    Trent W. Batchelor

    2016-01-01

    Full Text Available This essay evaluates the impact of the International Financial Reporting Standards on the pricing of the credit default swap (CDS market. The purpose extended to application of the evaluation synthesized into a best-fit strategy for participants of the CDS market as designated the buyers, and sellers. The impact of IFRS 9 on the pricing of the CDS market, using an event study method, integrates into an accounting strategy allowing the seller of protection to reduce asset value instead of creating revenue on an uncertain financial asset. The results of the study first that regulation has an effect on notional prices of credit default swaps and second that cumulative abnormal return exists in the financial sector as compared to the CDS market. A best-fit strategy for buyers and sellers of protection using derivatives known as credit default swaps in an attempt to exercise the inefficiencies created by the pricing of the CDS derivative instruments.

  19. Default Rate and Price of Capital in a Costly External Finance Model

    Directory of Open Access Journals (Sweden)

    Juan Pablo Medina

    2006-03-01

    Full Text Available Financial frictions have been used to enrich mechanisms transmission in macroeconomics. However, the predictions of real business cycle models of costly external finance imply a procyclical default rate, external premium and relative price of capital which seems at odds with the data. In this article, we include technology shocks that affect the average productivity and idiosyncratic risk of capital producers in a standard costly external finance model. These elements enhance the model to deliver a countercyclical default rate, external finance and relative price of capital premium which are more consistent with the data and contrary to the results obtained with a sector-neutral productivity shock. Intuitively, if the entrepreneurs’ investment projects become more productive in average, the relative price of capital and the default rate fall while investment and output increase. Using data on the relative price of capital, we perform a calibration of this type of shocks which highlights its business-cycle relevance.

  20. Governance-Default Risk Relationship and the Demand for Intermediated and Non-Intermediated Debt

    Directory of Open Access Journals (Sweden)

    Husam Aldamen

    2012-09-01

    Full Text Available This paper explores the impact of corporate governance on the demand for intermediated debt (asset finance, bank debt, non-bank private debt and non-intermediated debt (public debt in the Australian debt market. Relative to other countries the Australian debt market is characterised by higher proportions of intermediated or private debt with a lower inherent level of information asymmetry in that private lenders have greater access to financial information (Gray, Koh & Tong 2009. Our firm level, cross-sectional evidence suggests that higher corporate governance impacts demand for debt via the mitigation of default risk. However, this relationship is not uniform across all debt types. Intermediated debt such as bank and asset finance debt are more responsive to changes in governance-default risk relationship than non-bank and non-intermediated debt. The implication is that a firm’s demand for different debt types will reflect its governance-default risk profile.

  1. Effect of standard tuberculosis treatment on naive, memory and regulatory T-cell homeostasis in tuberculosis-diabetes co-morbidity.

    Science.gov (United States)

    Kumar, Nathella P; Moideen, Kadar; Viswanathan, Vijay; Kornfeld, Hardy; Babu, Subash

    2016-09-01

    Perturbations in CD4(+) and CD8(+) T-cell phenotype and function are hallmarks of tuberculosis-diabetes co-morbidity. However, their contribution to the pathogenesis of this co-morbidity and the effect of anti-tuberculosis treatment on the phenotype of the T-cell subsets is poorly understood. In this study, we examined the frequency of different T-cell subsets in individuals with pulmonary tuberculosis (PTB) with diabetes mellitus (DM) or without coincident diabetes mellitus (NDM) before, during and after completion of anti-tuberculosis chemotherapy. PTB-DM is characterized by heightened frequencies of central memory CD4(+) and CD8(+) T cells and diminished frequencies of naive, effector memory and/or effector CD4(+) and CD8(+) T cells at baseline and after 2 months of treatment but not following treatment completion in comparison with PTB-NDM. Central memory CD4(+) and CD8(+) T-cell frequencies exhibited a positive correlation with fasting blood glucose and glycated haemoglobin A1c levels, whereas the frequencies of naive and effector memory or effector CD4(+) and CD8(+) T cells exhibited a negative correlation. However, the frequencies of CD4(+) and CD8(+) T-cell subsets in individuals with PTB exhibited no significant relationship with bacterial burdens. Finally, although minor alterations in the T-cell subset compartment were observed at 2 months of treatment, significantly decreased frequencies of central memory and significantly enhanced frequencies of naive CD4(+) and CD8(+) T cells were observed at the completion of treatment. Our data reveal a profound effect of coexistent diabetes on the altered frequencies of central memory, effector memory and naive T cells and its normalization following therapy. PMID:27289086

  2. Contribution of computed tomography guided percutaneous drainage of tuberculous cold abscesses adjunctive to pharmaceutical anti-tubercular treatment

    International Nuclear Information System (INIS)

    Purpose: To determine the efficiency and safety of the percutaneous aspiration and drainage of rare touberculous cold abscesses under CT guidance. Materials and methods: We retrospectively studied 63 cases of 44 patients, treated in our hospital during the last two years. They suffered from tuberculous infection complicated with tuberculous cold abscesses variously located. All these patients underwent percutaneous aspiration and drainage under CT imaging, following the trocar puncture technique. The catheter remained in place for about a week. A follow up CT scan was performed in all cases before the catheter removal. Some of the patients were under anti tuberculosis medication. Results: All the patients had a successful recovery from the abscesses. There were no major or minor complications observed. No recurrence occurred until today. Conclusion: CT guided percutaneous aspiration and drainage of tuberculous cold abscesses is a safe, minimal invasive and effective method of treatment. Drainage and specific antituberculosis therapy leads to a satisfactory conclusion.

  3. HIERtalker: A default hierarchy of high order neural networks that learns to read English aloud

    Energy Technology Data Exchange (ETDEWEB)

    An, Z.G.; Mniszewski, S.M.; Lee, Y.C.; Papcun, G.; Doolen, G.D.

    1988-01-01

    A new learning algorithm based on a default hierarchy of high order neural networks has been developed that is able to generalize as well as handle exceptions. It learns the ''building blocks'' or clusters of symbols in a stream that appear repeatedly and convey certain messages. The default hierarchy prevents a combinatoric explosion of rules. A simulator of such a hierarchy, HIERtalker, has been applied to the conversion of English words to phonemes. Achieved accuracy is 99% for trained words and ranges from 76% to 96% for sets of new words. 8 refs., 4 figs., 1 tab.

  4. A Multi-industry Default Prediction Model using Logistic Regression and Decision Tree

    Directory of Open Access Journals (Sweden)

    Suresh Ramakrishnan

    2015-04-01

    Full Text Available The accurate prediction of corporate bankruptcy for the firms in different industries is of a great concern to investors and creditors, as the reduction of creditors’ risk and a considerable amount of saving for an industry economy can be possible. Financial statements vary between industries. Therefore, economic intuition suggests that industry effects should be an important component in bankruptcy prediction. This study attempts to detail the characteristics of each industry using sector indicators. The results show significant relationship between probability of default and sector indicators. The results of this study may improve the default prediction models performance and reduce the costs of risk management.

  5. An Empirical Analysis of the Default Rate of Informal Lending—Evidence from Yiwu, China

    Science.gov (United States)

    Lu, Wei; Yu, Xiaobo; Du, Juan; Ji, Feng

    This study empirically analyzes the underlying factors contributing to the default rate of informal lending. This paper adopts snowball sampling interview to collect data and uses the logistic regression model to explore the specific factors. The results of these analyses validate the explanation of how the informal lending differs from the commercial loan. Factors that contribute to the default rate have particular attributes, while sharing some similarities with commercial bank or FICO credit scoring Index. Finally, our concluding remarks draw some inferences from empirical analysis and speculate as to what this may imply for the role of formal and informal financial sectors.

  6. A Non-Gaussian Panel Time Series Model for Estimating and Decomposing Default Risk

    OpenAIRE

    Koopman, S.J.; Lucas, A.; Daniels, R

    2005-01-01

    This discussion paper led to an article in the Journal of Business and Economic Statistics (2008). Vol. 26, issue 4, pages 510-525. We model 1981–2002 annual US default frequencies for a panel of firms in different rating and age classes. The data is decomposed into a systematic and firm-specific risk component, where the systematic component reflects the general economic conditions and default climate. We have to cope with (i) the shared exposure of each age cohort and rating class to the sa...

  7. A General Scheme for Formalizing Defaults Using the Predicate ab(I,S)

    Institute of Scientific and Technical Information of China (English)

    SHEN Yidong

    1999-01-01

    In common sense reasoning two typical types of defaultsare encountered. One is of the form "All birds can fly except b1,b2,..., and bm (m1)", and the other "All birds can fly,but there exist exceptions". The first type of defaults is readilyformalized but the other, as some researchers have noticed, is difficultto deal with. This paper establishes a general scheme for formalizing defaults of the two types, the key to which is the introduction of atwo-argument predicate ab (I, S) to represent exceptional objects.

  8. SU-E-J-36: Comparison of CBCT Image Quality for Manufacturer Default Imaging Modes

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, G [University of Wisconsin, Madison, WI (United States)

    2015-06-15

    Purpose CBCT is being increasingly used in patient setup for radiotherapy. Often the manufacturer default scan modes are used for performing these CBCT scans with the assumption that they are the best options. To quantitatively assess the image quality of these scan modes, all of the scan modes were tested as well as options with the reconstruction algorithm. Methods A CatPhan 504 phantom was scanned on a TrueBeam Linear Accelerator using the manufacturer scan modes (FSRT Head, Head, Image Gently, Pelvis, Pelvis Obese, Spotlight, & Thorax). The Head mode scan was then reconstructed multiple times with all filter options (Smooth, Standard, Sharp, & Ultra Sharp) and all Ring Suppression options (Disabled, Weak, Medium, & Strong). An open source ImageJ tool was created for analyzing the CatPhan 504 images. Results The MTF curve was primarily dictated by the voxel size and the filter used in the reconstruction algorithm. The filters also impact the image noise. The CNR was worst for the Image Gently mode, followed by FSRT Head and Head. The sharper the filter, the worse the CNR. HU varied significantly between scan modes. Pelvis Obese had lower than expected HU values than most while the Image Gently mode had higher than expected HU values. If a therapist tried to use preset window and level settings, they would not show the desired tissue for some scan modes. Conclusion Knowing the image quality of the set scan modes, will enable users to better optimize their setup CBCT. Evaluation of the scan mode image quality could improve setup efficiency and lead to better treatment outcomes.

  9. 供应链违约风险传染度量模型%Supply Chain Default Risk Contagion Model

    Institute of Scientific and Technical Information of China (English)

    张圣忠; 庞春媛; 李倩

    2014-01-01

    In order to analyze how the causal contagion and default contagion influences the supply chain default risk,this paper set up a supply chain default risk contagion model by adding the factor of default correlation into intensity model.The members’default probability change in the two-level and three-level supply chain shows one member’s default will cause a forward leap on other related members’default intensity by contagion.Incidence coefficients of default probability can be a reference to control the partners’risk for members in the supply chain.%为了分析因果传染和违约传染对供应链违约风险的影响,在强度模型的基础上引入违约相关因素,构建供应链违约风险传染度量模型。通过比较两级和三级供应链情形下成员企业的违约概率变化可以发现,一个成员企业违约会通过传染的方式引起关联企业违约强度的正向跳跃。违约概率的关联系数可以为供应链成员企业控制合作伙伴风险提供依据。

  10. 存在违约风险时的最优资产组合%Optimal Portfolio with Default Risk

    Institute of Scientific and Technical Information of China (English)

    卞世博; 刘海龙

    2012-01-01

    本文研究了当存在违约风险时,一个代表性投资者投资于一个可违约债券、股票以及银行存款的最优资产配置问题.利用简约化模型来刻画可违约债券的违约风险,并给出其价格的动态过程.通过随机控制方法给出了此优化问题的解析解.结果表明跳跃(违约)风险的存在,使可违约债券的最优投资策略不再是连续函数.当可违约债券违约时,投资者对可违约债券的持有量为零;当债券未发生违约时,投资者对可违约债券的最优持有量主要受信用利差、违约强度以及投资期限的影响.%In the "classical" optimal portfolio literature, only market risk or cognitive risk associated with market is considered. In spite of their several major contributions to the theory of optimal asset selection only a handful of papers consider the case where one or more of the securities in the portfolio are subject to default risk. These authors use a diversification argument implying that jump risk do not show up in well-diversified portfolios of defaultable bonds and the impact of jump risk on portfolio management cannot be studied. In this paper we research a representative investor on how she optimally allocated her wealth among the following securities: a defaultable bond, a stock and a bank account. Because we assume that the investor invests a defaultable bond, there is jump risk in defaultable bond. Bring the jump risk into the investment portfolio is key innovation of this paper. We adopt the reduced-form approach to model the defaultable bond, and give the dynamics of defaultable bond. If the investor's utility is CRRA and stochastic control methods are adopted, we can obtain closed form solutions for the optimal strategies. The optimal strategy for the stock is constant irrespective of pre-default or post-default. The reason is that the stock has no correlation with the defaultable bond, which means there is no need to hedge for the default

  11. Aberrant functional connectivity of default-mode network in type 2 diabetes patients

    International Nuclear Information System (INIS)

    Type 2 diabetes mellitus is associated with increased risk for dementia. Patients with impaired cognition often show default-mode network disruption. We aimed to investigate the integrity of a default-mode network in diabetic patients by using independent component analysis, and to explore the relationship between network abnormalities, neurocognitive performance and diabetic variables. Forty-two patients with type 2 diabetes and 42 well-matched healthy controls were included and underwent resting-state functional MRI in a 3 Tesla unit. Independent component analysis was adopted to extract the default-mode network, including its anterior and posterior components. Z-maps of both sub-networks were compared between the two groups and correlated with each clinical variable. Patients showed increased connectivity around the medial prefrontal cortex in the anterior sub-network, but decreased connectivity around the posterior cingulate cortex in the posterior sub-network. The decreased connectivity in the posterior part was significantly correlated with the score on Complex Figure Test-delay recall test (r = 0.359, p = 0.020), the time spent on Trail-Making Test-part B (r = -0.346, p = 0.025) and the insulin resistance level (r = -0.404, p = 0.024). Dissociation pattern in the default-mode network was found in diabetic patients, which might provide powerful new insights into the neural mechanisms that underlie the diabetes-related cognitive decline. (orig.)

  12. 7 CFR 1493.500 - Notice of default and claims for loss.

    Science.gov (United States)

    2010-01-01

    ... importer obligation; (ii) Depending upon the method of shipment, the negotiable ocean carrier or intermodal..., FOB, CFR or CIF values; or (B) If there was an intervening purchaser, both the exporter's invoice to... obligation, the exporter or the exporter's assignee must submit a notice of default to CCC as soon...

  13. Default risk, bankruptcy procedures and the market value of life insurance liabilities

    NARCIS (Netherlands)

    A. Chen; M. Suchanecki

    2007-01-01

    The topic of insolvency risk in connection with life insurance companies has recently attracted a great deal of attention. In this paper, the question is investigated of how the values of the equity and of the liability of a life insurance company are affected by the default risk and the choice of t

  14. Altered default mode network activity in patient with anxiety disorders: An fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xiaohu [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China) and Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: xhzhao999@263.net; Wang Peijun [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: tongjipjwang@vip.sina.com; Li Chunbo [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: licb@mail.tongji.edu.cn; Hu Zhenghui [Department of Electrical and Engineering, Hong Kong University of Science and Technology, Hong Kong (China)], E-mail: eezhhu@ust.hk; Xi Qian [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: 96125007@sina.com.cn; Wu Wenyuan [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: wuwy@mail.tongji.edu.cn; Tang Xiaowei [Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: tangxw@zju.edu.cn

    2007-09-15

    Anxiety disorder, a common mental disorder in our clinical practice, is characterized by unprovoked anxiety. Medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC), which closely involved in emotional processing, are critical regions in the default mode network. We used functional magnetic resonance imaging (fMRI) to investigate whether default mode network activity is altered in patients with anxiety disorder. Ten anxiety patients and 10 healthy controls underwent fMRI while listening to emotionally neutral words alternating with rest (Experiment 1) and threat-related words alternating with emotionally neutral words (Experiment 2). In Experiment 1, regions of deactivation were observed in patients and controls. In Experiment 2, regions of deactivation were observed only in patients. The observed deactivation patterns in the two experiments, which included MPFC, PCC, and inferior parietal cortex, were similar and consistent with the default model network. Less deactivation in MPFC and greater deactivation in PCC were observed for patients group comparing to controls in Experiment 1. Our observations suggest that the default model network is altered in anxiety patients and dysfunction in MPFC and PCC may play an important role in anxiety psychopathology.

  15. Default mode network in the effects of Δ9-Tetrahydrocannabinol (THC on human executive function.

    Directory of Open Access Journals (Sweden)

    Matthijs G Bossong

    Full Text Available Evidence is increasing for involvement of the endocannabinoid system in cognitive functions including attention and executive function, as well as in psychiatric disorders characterized by cognitive deficits, such as schizophrenia. Executive function appears to be associated with both modulation of active networks and inhibition of activity in the default mode network. In the present study, we examined the role of the endocannabinoid system in executive function, focusing on both the associated brain network and the default mode network. A pharmacological functional magnetic resonance imaging (fMRI study was conducted with a placebo-controlled, cross-over design, investigating effects of the endocannabinoid agonist Δ9-tetrahydrocannabinol (THC on executive function in 20 healthy volunteers, using a continuous performance task with identical pairs. Task performance was impaired after THC administration, reflected in both an increase in false alarms and a reduction in detected targets. This was associated with reduced deactivation in a set of brain regions linked to the default mode network, including posterior cingulate cortex and angular gyrus. Less deactivation was significantly correlated with lower performance after THC. Regions that were activated by the continuous performance task, notably bilateral prefrontal and parietal cortex, did not show effects of THC. These findings suggest an important role for the endocannabinoid system in both default mode modulation and executive function. This may be relevant for psychiatric disorders associated with executive function deficits, such as schizophrenia and ADHD.

  16. Aberrant functional connectivity of default-mode network in type 2 diabetes patients

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Ying; Jiao, Yun; Chen, Hua-Jun; Ding, Jie; Luo, Bing; Peng, Cheng-Yu; Ju, Sheng-Hong; Teng, Gao-Jun [Medical School of Southeast University, Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Nanjing, Jiangsu (China)

    2015-11-15

    Type 2 diabetes mellitus is associated with increased risk for dementia. Patients with impaired cognition often show default-mode network disruption. We aimed to investigate the integrity of a default-mode network in diabetic patients by using independent component analysis, and to explore the relationship between network abnormalities, neurocognitive performance and diabetic variables. Forty-two patients with type 2 diabetes and 42 well-matched healthy controls were included and underwent resting-state functional MRI in a 3 Tesla unit. Independent component analysis was adopted to extract the default-mode network, including its anterior and posterior components. Z-maps of both sub-networks were compared between the two groups and correlated with each clinical variable. Patients showed increased connectivity around the medial prefrontal cortex in the anterior sub-network, but decreased connectivity around the posterior cingulate cortex in the posterior sub-network. The decreased connectivity in the posterior part was significantly correlated with the score on Complex Figure Test-delay recall test (r = 0.359, p = 0.020), the time spent on Trail-Making Test-part B (r = -0.346, p = 0.025) and the insulin resistance level (r = -0.404, p = 0.024). Dissociation pattern in the default-mode network was found in diabetic patients, which might provide powerful new insights into the neural mechanisms that underlie the diabetes-related cognitive decline. (orig.)

  17. The Influence of Homebuyer Education on Default and Foreclosure Risk: A Natural Experiment

    Science.gov (United States)

    Brown, Scott R.

    2016-01-01

    The recent housing crisis has generated debate over the benefits and risks of policies and programs promoting homeownership for low and moderate income households. One important facet of this conversation is whether prepurchase homebuyer education (HBE) is effective in reducing default or foreclosure risk. Studies to date have primarily focused on…

  18. Logic, Beliefs, and Instruction: A Test of the Default Interventionist Account of Belief Bias

    Science.gov (United States)

    Handley, Simon J.; Newstead, Stephen E.; Trippas, Dries

    2011-01-01

    According to dual-process accounts of thinking, belief-based responses on reasoning tasks are generated as default but can be intervened upon in favor of logical responding, given sufficient time, effort, or cognitive resource. In this article, we present the results of 5 experiments in which participants were instructed to evaluate the…

  19. 34 CFR 668.186 - Notice of your official cohort default rate.

    Science.gov (United States)

    2010-07-01

    ... POSTSECONDARY EDUCATION, DEPARTMENT OF EDUCATION STUDENT ASSISTANCE GENERAL PROVISIONS Two Year Cohort Default... packages as posted on the Department's Web site, to report any problem with receipt of the electronic... report a problem with the receipt of the electronic transmission of your eCDR notification package...

  20. Default Path and Dedicated Path: A New Approach to Realize IP Directly Over WDM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Combining IP and WDM is an attractive direction for research. Instead the point to point linking method, this paper proposes a new approach to realize IP directly over WDM, called DPDP (default path and dedicated path), presents a conceivable architecture in detail and explains its working procedure. A lot of problems related with this design are also discussed.

  1. A Special Report on the Alaska Commission on Postsecondary Education--Collection of Defaulted Student Loans.

    Science.gov (United States)

    Welker, Randy S.

    In accordance with a Legislative Budget and Audit Committee special request and the provisions of Title 24 of the Alaska Statutes, a review was conducted of the Alaska Commission on Postsecondary Education's experience with various collection contractors used to collect defaulted student loans. The primary purpose was to assess the success that…

  2. Resting-state connectivity in the default mode network and insula during experimental low back pain

    Institute of Scientific and Technical Information of China (English)

    Shanshan Zhang; Wen Wu; Guozhi Huang; Ziping Liu; Shigui Guo; Jianming Yang; Kangling Wang

    2014-01-01

    Functional magnetic resonance imaging studies have shown that the insular cortex has a signif-icant role in pain identiifcation and information integration, while the default mode network is associated with cognitive and memory-related aspects of pain perception. However, changes in the functional connectivity between the default mode network and insula during pain remain unclear. This study used 3.0 T functional magnetic resonance imaging scans in 12 healthy sub-jects aged 24.8 ± 3.3 years to compare the differences in the functional activity and connectivity of the insula and default mode network between the baseline and pain condition induced by intramuscular injection of hypertonic saline. Compared with the baseline, the insula was more functionally connected with the medial prefrontal and lateral temporal cortices, whereas there was lower connectivity with the posterior cingulate cortex, precuneus and inferior parietal lobule in the pain condition. In addition, compared with baseline, the anterior cingulate cortex exhibited greater connectivity with the posterior insula, but lower connectivity with the anterior insula, during the pain condition. These data indicate that experimental low back pain led to dysfunction in the connectivity between the insula and default mode network resulting from an impairment of the regions of the brain related to cognition and emotion, suggesting the impor-tance of the interaction between these regions in pain processing.

  3. Liquidity crisis detection: An application of log-periodic power law structures to default prediction

    Science.gov (United States)

    Wosnitza, Jan Henrik; Denz, Cornelia

    2013-09-01

    We employ the log-periodic power law (LPPL) to analyze the late-2000 financial crisis from the perspective of critical phenomena. The main purpose of this study is to examine whether LPPL structures in the development of credit default swap (CDS) spreads can be used for default classification. Based on the different triggers of Bear Stearns’ near bankruptcy during the late-2000 financial crisis and Ford’s insolvency in 2009, this study provides a quantitative description of the mechanism behind bank runs. We apply the Johansen-Ledoit-Sornette (JLS) positive feedback model to explain the rise of financial institutions’ CDS spreads during the global financial crisis 2007-2009. This investigation is based on CDS spreads of 40 major banks over the period from June 2007 to April 2009 which includes a significant CDS spread increase. The qualitative data analysis indicates that the CDS spread variations have followed LPPL patterns during the global financial crisis. Furthermore, the univariate classification performances of seven LPPL parameters as default indicators are measured by Mann-Whitney U tests. The present study supports the hypothesis that discrete scale-invariance governs the dynamics of financial markets and suggests the application of new and fast updateable default indicators to capture the buildup of long-range correlations between creditors.

  4. Pricing model of credit default swap with stochastic foreign exchange rate

    Directory of Open Access Journals (Sweden)

    WANG Yang

    2013-04-01

    Full Text Available A pricing model is established by using the structure approach and the backward Kolmogrov equation under the assumption of stochastic foreign exchange rate.The explicit solution of credit default swap is obtained for the dollar market.And a correlative financial analysis is given.

  5. Flu and Finances: Influenza Outbreaks and Loan Defaults in US Cities, 2004–2012

    Science.gov (United States)

    Collins, J. Michael; Schmeiser, Maximilian D.

    2015-01-01

    Objectives. We examined the association between influenza outbreaks in 83 metropolitan areas and credit card and mortgage defaults, as measured in quarterly zip code–level credit data over the period of 2004 to 2012. Methods. We used ordinary least squares, fixed effects, and 2-stage least squares instrumental variables regression strategies to examine the relationship between influenza-related Google searches and 30-, 60-, and 90-day credit card and mortgage delinquency rates. Results. We found that a proxy for influenza outbreaks is associated with a small but statistically significant increase in credit card and mortgage default rates, net of other factors. These effects are largest for 90-day defaults, suggesting that influenza outbreaks have a disproportionate impact on vulnerable borrowers who are already behind on their payments. Conclusions. Overall, it appears there is a relationship between exogenous health shocks (such as influenza) and credit default. The results suggest that consumer finances could benefit from policies that aim to reduce the financial shocks of illness, particularly for vulnerable borrowers. PMID:26180971

  6. Close-Form Pricing of Benchmark Equity Default Swaps Under the CEV Assumption

    NARCIS (Netherlands)

    Campi, L.; Sbuelz, A.

    2005-01-01

    Equity Default Swaps are new equity derivatives designed as a product for credit investors.Equipped with a novel pricing result, we provide closedform values that give an analytic contribution to the viability of cross-asset trading related to credit risk.

  7. 24 CFR 201.50 - Lender efforts to cure the default.

    Science.gov (United States)

    2010-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES TITLE I PROPERTY IMPROVEMENT AND MANUFACTURED HOME LOANS Default Under the Loan Obligation § 201... co-signer, and shall place in the loan file a copy of any modification agreement or repayment...

  8. Credit Default and Business Cycles: An Empirical Investigation of Brazilian Retail Loans

    Directory of Open Access Journals (Sweden)

    Arnildo da Silva Correa

    2014-09-01

    Full Text Available We use microdata from the Credit Information System (SCR of the Central Bank of Brazil to study the relationship between credit default and business cycles. In particular, we study the first part of the argument underlying the discussion about procyclicality related to the Basel II Accord: that recessions might increase credit defaults and have adverse impacts on the losses in portfolios of lender institutions. We explore both time series and cross-sectional variation in the data. Our data on the individual level are composed of retail loan transactions in two modalities-Consumer Credit and Vehicle Financing-from 2003 to 2008. Our results support the idea of a negative relationship between business cycles and credit default, but less strong than suggested in previous studies that use corporate data. We also find low and dispersed default correlations, and smaller losses in Value at Risk (VaR experiments than those found in the literature. These results may be possibly explained by the fact that, in the retail sector, loans are given to a large number of individuals, which may help to diversify risks.

  9. THE RELATIONSHIP BETWEEN MACROECONOMIC VARIABLES AND ROMANIAN CORPORATE DEFAULT RATES BETWEEN 2002-2008

    Directory of Open Access Journals (Sweden)

    Suveg Orsolya

    2011-07-01

    Full Text Available During its 20 year history of market economy, Romania experienced the most severe downturn in 2009, which resulted in many cost, mainly because of the output loss. These conditions forced several firms to declare bankruptcy and to stop their activity. The aim of this research is to assess the relationship between the corporate default rates and the macroeconomic processes in the case of Romania for the period comprised between 2002Q1-2008Q4. For this, based on the relevant literature, we ranked the potential explanatory variables of the default rates into seven groups: cyclical indicators, household indicators, corporate indicators, external sector indicators, price stability indicators and interest rates, loans to private sector and finally the capital market indicators. Some studies base their results only on accounting data, others only on market data. Our study focuses on both, since this seems to be an adequate approach in capturing most of the processes. Similar to the banks loan portfolio structure, we conducted analysis for five sectors: industry, construction, agriculture, services and the overall economy. For each sector the average default probability at time t is modeled as a logistic function of many general and sector-specific macroeconomic variables. The use of logistic regression was motivated by its ability to account for fractional data between 0 and 1. We found that at least one variable from each group has a significant explanatory power regarding the evolution of the default rates in all five sectors analyzed. In some cases the sign of the variables was the opposite of what the economic theory would have suggested, but it has to be taken into account that Romania posted the picture of an overheated economy during the analyzed period. Another important conclusion was that many variables were significant through their lagged value, which indicates an even better supervision of the evolution of the specific variables. From all

  10. Default mode network segregation and social deficits in autism spectrum disorder: Evidence from non-medicated children.

    Science.gov (United States)

    Yerys, Benjamin E; Gordon, Evan M; Abrams, Danielle N; Satterthwaite, Theodore D; Weinblatt, Rachel; Jankowski, Kathryn F; Strang, John; Kenworthy, Lauren; Gaillard, William D; Vaidya, Chandan J

    2015-01-01

    Functional pathology of the default mode network is posited to be central to social-cognitive impairment in autism spectrum disorders (ASD). Altered functional connectivity of the default mode network's midline core may be a potential endophenotype for social deficits in ASD. Generalizability from prior studies is limited by inclusion of medicated participants and by methods favoring restricted examination of network function. This study measured resting-state functional connectivity in 22 8-13 year-old non-medicated children with ASD and 22 typically developing controls using seed-based and network segregation functional connectivity methods. Relative to controls the ASD group showed both under- and over-functional connectivity within default mode and non-default mode regions, respectively. ASD symptoms correlated negatively with the connection strength of the default mode midline core-medial prefrontal cortex-posterior cingulate cortex. Network segregation analysis with the participation coefficient showed a higher area under the curve for the ASD group. Our findings demonstrate that the default mode network in ASD shows a pattern of poor segregation with both functional connectivity metrics. This study confirms the potential for the functional connection of the midline core as an endophenotype for social deficits. Poor segregation of the default mode network is consistent with an excitation/inhibition imbalance model of ASD.

  11. Default mode network segregation and social deficits in autism spectrum disorder: Evidence from non-medicated children

    Directory of Open Access Journals (Sweden)

    Benjamin E. Yerys

    2015-01-01

    Full Text Available Functional pathology of the default mode network is posited to be central to social-cognitive impairment in autism spectrum disorders (ASD. Altered functional connectivity of the default mode network's midline core may be a potential endophenotype for social deficits in ASD. Generalizability from prior studies is limited by inclusion of medicated participants and by methods favoring restricted examination of network function. This study measured resting-state functional connectivity in 22 8–13 year-old non-medicated children with ASD and 22 typically developing controls using seed-based and network segregation functional connectivity methods. Relative to controls the ASD group showed both under- and over-functional connectivity within default mode and non-default mode regions, respectively. ASD symptoms correlated negatively with the connection strength of the default mode midline core—medial prefrontal cortex–posterior cingulate cortex. Network segregation analysis with the participation coefficient showed a higher area under the curve for the ASD group. Our findings demonstrate that the default mode network in ASD shows a pattern of poor segregation with both functional connectivity metrics. This study confirms the potential for the functional connection of the midline core as an endophenotype for social deficits. Poor segregation of the default mode network is consistent with an excitation/inhibition imbalance model of ASD.

  12. Ag85A DNA疫苗加强免疫显著提高卡介苗初免小鼠的抗结核T细胞免疫应答%Ag85A DNA vaccination boosting enhances BCG primed-mice anti-tuberculosis T cell responses

    Institute of Scientific and Technical Information of China (English)

    康涵; 范小勇; 袁琴; 吴福明; 沈芳

    2013-01-01

    Objective To construct DNA vaccine expressing Mycobacterium tuberculosis(Mtb) immunodominant antigen Ag85A and analyze its anti-tuberculosis T cell responses in BCG primed-mice after DNA vaccination boosting.Methods The coding gene of Ag85A mature fragment was amplified by PCR with H37Rv genomic DNA as template,and then cloned into the eukaryotic expression vector pVAX1 to construct Ag85A DNA vaccine.After purification,Ag85A DNA vaccine was injected intramuscularly twice in BCG primed-mice with BCG vaccination and DNA vaccination alone as control.Eight weeks post-vaccination,spleen lymphocytes were separated and were then used to analyze Mtb antigen specific effector T cell response and polyfuntional IFN-γ/TNF-α/IL-2 secreting CD4+ T cell frequencies and intensities,and CD8+T cell responses by IFN-γ ELISPOT assay and intracellular staining,respectively.Results Compared to BCG vaccinated-and DNA vaccinated-mice,Ag85A DNA boosting not only enhanced significantly BCG primed-mice IFN-γ+TNF-α+IL-2+,IFN-γ+ IL-2+,TNF-α+IL-2+ and IL-2+ CD4+ T cell frequencies and IL-2 secretion,but also improved significantly IFN-γ-secreting and IL-2-secreting CD8+ T cell frequencies.Condusion Ag85A DNA vaccine was constructed successfully and was demonstrated to enhance significantly BCG primed-mice Mtb antigen specific CD4+ and CD8+ T cell responses when boosting,which is beneficial to improve BCG immunogenicity and its waning immune protection against Mtb.%目的 构建表达结核分枝杆菌(Mycobacterium tuberculosis,Mtb)免疫优势抗原Ag85A的DNA疫苗,分析其加强免疫后提高卡介苗(BCG)初免小鼠的抗结核T细胞免疫应答.方法 以Mtb毒株H37Rv基因组DNA为模板,PCR扩增Ag85A抗原编码的结构基因并克隆至真核表达载体pVAX1中构建其DNA疫苗;接着,将纯化后的该DNA疫苗加强免疫BCG初免小鼠2针,以BCG和DNA单独免疫小鼠为对照,免疫8周后无菌分离脾淋巴细胞,分别应用IFN-γ ELISPOT和多

  13. Changes in the default mode network in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users

    Institute of Scientific and Technical Information of China (English)

    Wenfu Hu; Xiangming Fu; Ruobing Qian; Xiangpin Wei; Xuebing Ji; Chaoshi Niu

    2012-01-01

    The default mode network is associated with senior cognitive functions in humans. In this study, we performed independent component analysis of blood oxygenation signals from 14 heroin users and 13 matched normal controls in the resting state through functional MRI scans. Results showed that the default mode network was significantly activated in the prefrontal lobe, posterior cingulated cortex and hippocampus of heroin users, and an enhanced activation signal was observed in the right inferior parietal lobule (P < 0.05, corrected for false discovery rate). Experimental findings indicate that the default mode network is altered in heroin users.

  14. Portfolio optimization in a defaults model under full/partial information

    CERN Document Server

    Lim, Thomas

    2010-01-01

    In this paper, we consider a financial market with assets exposed to some risks inducing jumps in the asset prices, and which can still be traded after default times. We use a default-intensity modeling approach, and address in this incomplete market context the problem of maximization of expected utility from terminal wealth for logarithmic, power and exponential utility functions. We study this problem as a stochastic control problem both under full and partial information. Our contribution consists in showing that the optimal strategy can be obtained by a direct approach for the logarithmic utility function, and the value function for the power utility function can be determined as the minimal solution of a backward stochastic differential equation. For the partial information case, we show how the problem can be divided into two problems: a filtering problem and an optimization problem. We also study the indifference pricing approach to evaluate the price of a contingent claim in an incomplete market and ...

  15. Musical Creativity "Revealed" in Brain Structure: Interplay between Motor, Default Mode, and Limbic Networks.

    Science.gov (United States)

    Bashwiner, David M; Wertz, Christopher J; Flores, Ranee A; Jung, Rex E

    2016-01-01

    Creative behaviors are among the most complex that humans engage in, involving not only highly intricate, domain-specific knowledge and skill, but also domain-general processing styles and the affective drive to create. This study presents structural imaging data indicating that musically creative people (as indicated by self-report) have greater cortical surface area or volume in a) regions associated with domain-specific higher-cognitive motor activity and sound processing (dorsal premotor cortex, supplementary and pre-supplementary motor areas, and planum temporale), b) domain-general creative-ideation regions associated with the default mode network (dorsomedial prefrontal cortex, middle temporal gyrus, and temporal pole), and c) emotion-related regions (orbitofrontal cortex, temporal pole, and amygdala). These findings suggest that domain-specific musical expertise, default-mode cognitive processing style, and intensity of emotional experience might all coordinate to motivate and facilitate the drive to create music. PMID:26888383

  16. Musical Creativity “Revealed” in Brain Structure: Interplay between Motor, Default Mode, and Limbic Networks

    Science.gov (United States)

    Bashwiner, David M.; Wertz, Christopher J.; Flores, Ranee A.; Jung, Rex E.

    2016-01-01

    Creative behaviors are among the most complex that humans engage in, involving not only highly intricate, domain-specific knowledge and skill, but also domain-general processing styles and the affective drive to create. This study presents structural imaging data indicating that musically creative people (as indicated by self-report) have greater cortical surface area or volume in a) regions associated with domain-specific higher-cognitive motor activity and sound processing (dorsal premotor cortex, supplementary and pre-supplementary motor areas, and planum temporale), b) domain-general creative-ideation regions associated with the default mode network (dorsomedial prefrontal cortex, middle temporal gyrus, and temporal pole), and c) emotion-related regions (orbitofrontal cortex, temporal pole, and amygdala). These findings suggest that domain-specific musical expertise, default-mode cognitive processing style, and intensity of emotional experience might all coordinate to motivate and facilitate the drive to create music. PMID:26888383

  17. Measuring the default risk of sovereign debt from the perspective of network

    Science.gov (United States)

    Chuang, Hongwei; Ho, Hwai-Chung

    2013-05-01

    Recently, there has been a growing interest in network research, especially in the fields of biology, computer science, and sociology. It is natural to address complex financial issues such as the European sovereign debt crisis from the perspective of network. In this article, we construct a network model according to the debt-credit relations instead of using the conventional methodology to measure the default risk. Based on the model, a risk index is examined using the quarterly report of consolidated foreign claims from the Bank for International Settlements (BIS) and debt/GDP ratios among these reporting countries. The empirical results show that this index can help the regulators and practitioners not only to determine the status of interconnectivity but also to point out the degree of the sovereign debt default risk. Our approach sheds new light on the investigation of quantifying the systemic risk.

  18. A mechanism for ultra-slow oscillations in the cortical default network.

    Science.gov (United States)

    Steyn-Ross, Moira L; Steyn-Ross, D A; Sleigh, J W; Wilson, M T

    2011-02-01

    When the brain is in its noncognitive "idling" state, functional MRI measurements reveal the activation of default cortical networks whose activity is suppressed during cognitive processing. This default or background mode is characterized by ultra-slow BOLD oscillations (∼0.05 Hz), signaling extremely slow cycling in cortical metabolic demand across distinct cortical regions. Here we describe a model of the cortex which predicts that slow cycling of cortical activity can arise naturally as a result of nonlinear interactions between temporal (Hopf) and spatial (Turing) instabilities. The Hopf instability is triggered by delays in the inhibitory postsynaptic response, while the Turing instability is precipitated by increases in the strength of the gap-junction coupling between interneurons. We comment on possible implications for slow dendritic computation and information processing. PMID:20821063

  19. Stochastic control under progressive enlargement of filtrations and applications to multiple defaults risk management

    CERN Document Server

    Pham, Huyen

    2010-01-01

    We formulate and investigate a general stochastic control problem under a progressive enlargement of filtration. The global information is enlarged from a reference filtration and the knowledge of multiple random times together with associated marks when they occur. By working under a density hypothesis on the conditional joint distribution of the random times and marks, we prove a decomposition of the original stochastic control problem under the global filtration into classical stochastic control problems under the reference filtration, which are determined in a finite backward induction. Our method revisits and extends in particular stochastic control of diffusion processes with finite number of jumps. This study is motivated by optimization problems arising in default risk management, and we provide applications of our decomposition result for the indifference pricing of defaultable claims, and the optimal investment under bilateral counterparty risk. The solutions are expressed in terms of BSDEs involvin...

  20. Inferring Acceptance and Rejection in Dialogue by Default Rules of Inference

    CERN Document Server

    Walker, M A

    1996-01-01

    This paper discusses the processes by which conversants in a dialogue can infer whether their assertions and proposals have been accepted or rejected by their conversational partners. It expands on previous work by showing that logical consistency is a necessary indicator of acceptance, but that it is not sufficient, and that logical inconsistency is sufficient as an indicator of rejection, but it is not necessary. I show how conversants can use information structure and prosody as well as logical reasoning in distinguishing between acceptances and logically consistent rejections, and relate this work to previous work on implicature and default reasoning by introducing three new classes of rejection: {\\sc implicature rejections}, {\\sc epistemic rejections} and {\\sc deliberation rejections}. I show how these rejections are inferred as a result of default inferences, which, by other analyses, would have been blocked by the context. In order to account for these facts, I propose a model of the common ground that...

  1. Surgery in the treatment of malignant pleural mesothelioma: recruitment into trials should be the default position

    OpenAIRE

    Datta, Avijit; Smith, Rhiannon; Fiorentino, Francesca; Treasure, Tom

    2013-01-01

    Background Europe is at the peak of an epidemic of malignant pleural mesothelioma and the burden of disease is likely to continue rising in the large areas of the world where asbestos remains unregulated. Patients with mesothelioma present with thoracic symptoms and radiological changes so respiratory physicians take a leading role in diagnosis and management. Belief that the modest survival times reported after radical surgery, whether alone or as part of multimodal therapy, are longer than ...

  2. Abnormal Brain Default-Mode Network Functional Connectivity in Drug Addicts

    OpenAIRE

    Ma, Ning; Liu, Ying; Fu, Xian-ming; Li, Nan; Wang, Chang-Xin; Zhang, Hao; Qian, Ruo-Bing; Xu, Hu-Sheng; Hu, Xiaoping; Zhang, Da-Ren

    2011-01-01

    Background The default mode network (DMN) is a set of brain regions that exhibit synchronized low frequency oscillations at resting-state, and is believed to be relevant to attention and self-monitoring. As the anterior cingulate cortex and hippocampus are impaired in drug addiction and meanwhile are parts of the DMN, the present study examined addiction-related alteration of functional connectivity of the DMN. Methodology Resting-state functional magnetic resonance imaging data of chronic he...

  3. Nudging Sustainable Food Choices. The Role of Defaults, Frames, Habits and Nature Relatedness

    OpenAIRE

    Hohle, Sigrid Møyner

    2014-01-01

    Reduced consumption of meat could help mitigate climate change and health problems. Nudging is one approach to individual behavior change. By nudging, the choice context is designed to facilitate certain decisions. In the present field experiment, three different nudges were tested, aiming at increasing vegetarian food selection among 353 customers in a café. The menu was changed so that the vegetarian food options were either presented as the dish of the day (DEFAULT) or given a more attra...

  4. Self-Processing and the Default Mode Network: Interactions with the Mirror Neuron System

    OpenAIRE

    Istvan Molnar-Szakacs; Lucina Q. Uddin

    2013-01-01

    Recent evidence for the fractionation of the default mode network (DMN) into functionally distinguishable subdivisions with unique patterns of connectivity calls for a reconceptualization of the relationship between this network and self-referential processing. Advances in resting-state functional connectivity analyses are beginning to reveal increasingly complex patterns of organization within the key nodes of the DMN - medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) – a...

  5. The recent elections may have only postponed Greece’s default and Eurozone exit

    OpenAIRE

    Halikiopoulou, Daphne; Vasilopoulou, Sofia

    2012-01-01

    Last Sunday’s elections in Greece saw the pro-bailout New Democracy party gain the largest share of the vote, reassuring many commentators who had been fearing a default by Greece or even its ejection from the Eurozone. Daphne Halikiopoulou and Sofia Vasilopoulou argue, however, that anti-bailout parties in Greece received widespread support – there is still a deep division in Greek politics. This cannot be solved until the underlying problems of corruption, nepotism and client...

  6. Age effect on the default mode network, inner thoughts, and cognitive abilities.

    OpenAIRE

    Mevel, Katell; Landeau, Brigitte; Fouquet, Marine; La Joie, Renaud; Villain, Nicolas; Mézenge, Florence; Perrotin, Audrey; Eustache, Francis; Desgranges, Beatrice; Chételat, Gaël

    2013-01-01

    International audience Age-related effects on the default mode network (DMN) connectivity as measured at rest using functional magnetic resonance imaging (fMRI) are now well described. Little is known however about the relationships between these changes and age-related effects on cognition or on the unconstrained thoughts which occur during the resting-state scan, called inner experience. Brain resting-state activity, inner experience, and cognitive ability measurements were obtained in 7...

  7. Potential impact of licensee default on cleanup of TMI-2. Technical report

    International Nuclear Information System (INIS)

    Financial repercussions of the accident at Three Mile Island Unit 2 on the ability of the Licensee, Metropolitan Edison Co., to complete cleanup of the facility are examined. Potential impacts of licensee default on cleanup and alternatives to minimize the potential of bankruptcy are discussed. Specific recommendations are made regarding steps the Nuclear Regulatory Commission might take in keeping with its regulatory functions and its mission to protect the public health and safety

  8. Default options in advance directives: study protocol for a randomised clinical trial

    OpenAIRE

    Gabler, Nicole B.; Cooney, Elizabeth; Small, Dylan S.; Troxel, Andrea B.; Arnold, Robert M.; White, Douglas B.; Angus, Derek C.; Loewenstein, George; Volpp, Kevin G; Bryce, Cindy L.; Halpern, Scott D.

    2016-01-01

    Introduction Although most seriously ill Americans wish to avoid burdensome and aggressive care at the end of life, such care is often provided unless patients or family members specifically request otherwise. Advance directives (ADs) were created to provide opportunities to set limits on aggressive care near life's end. This study tests the hypothesis that redesigning ADs such that comfort-oriented care is provided as the default, rather than requiring patients to actively choose it, will pr...

  9. The default mode network and social understanding of others: what do brain connectivity studies tell us

    OpenAIRE

    Li, Wanqing; Mai, Xiaoqin; Liu, Chao

    2014-01-01

    The Default Mode Network (DMN) has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common resu...

  10. The Default Mode Network and Social Understanding of Others: What do Brain Connectivity Studies Tell Us

    OpenAIRE

    Wanqing eLi; Xiaoqin eMai; Chao eLiu

    2014-01-01

    The Default Mode Network (DMN) has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common res...

  11. Differential Deactivation during Mentalizing and Classification of Autism Based on Default Mode Network Connectivity

    OpenAIRE

    Murdaugh, Donna L.; Shinkareva, Svetlana V.; Deshpande, Hrishikesh R.; Jing Wang; Pennick, Mark R; Kana, Rajesh K.

    2012-01-01

    The default mode network (DMN) is a collection of brain areas found to be consistently deactivated during task performance. Previous neuroimaging studies of resting state have revealed reduced task-related deactivation of this network in autism. We investigated the DMN in 13 high-functioning adults with autism spectrum disorders (ASD) and 14 typically developing control participants during three fMRI studies (two language tasks and a Theory-of-Mind (ToM) task). Each study had separate blocks ...

  12. Alterations of Resting State Functional Connectivity in the Default Network in Adolescents with Autism Spectrum Disorders

    OpenAIRE

    Weng, Shih-Jen; Wiggins, Jillian Lee; Peltier, Scott J.; Carrasco, Melisa; Risi, Susan; Lord, Catherine; Monk, Christopher S.

    2009-01-01

    Autism spectrum disorders (ASD) are associated with disturbances of neural connectivity. Functional connectivity between neural structures is typically examined within the context of a cognitive task, but also exists in the absence of a task (i.e., “rest”). Connectivity during rest is particularly active in a set of structures called the default network, which includes the posterior cingulate cortex (PCC), retrosplenial cortex, lateral parietal cortex/angular gyrus, medial prefrontal cortex, ...

  13. A default prior distribution for contingency tables with dependent factor levels

    OpenAIRE

    Overstall, Antony M.; King, Ruth

    2014-01-01

    A default prior distribution is proposed for the Bayesian analysis of contingency tables. The prior is specified to allow for dependence between levels of the factors. Different dependence structures are considered, including conditional autoregressive and distance correlation structures. To demonstrate the prior distribution, a dataset is considered which involves estimating the number of injecting drug users in the eleven National Health Service board regions of Scotland using an incomplete...

  14. Beyond the transaction: depository institutions and reduced mortgage default for low-income homebuyers

    OpenAIRE

    O. Emre Ergungor; Stephanie Moulton

    2011-01-01

    We evaluate the effects of the lending institution and soft information on mortgage loan performance for low-income homebuyers. We find that even after controlling for bank selection, those who receive a loan from a local bank are significantly less likely to become delinquent or default than other bank or nonbank borrowers, suggesting an information effect. These effects are most pronounced for higher-risk borrowers, who likely benefit more from informational advantages of local banks. These...

  15. State dissolution, sovereign debt and default:Lessons from the UK and Ireland, 1920-1938

    OpenAIRE

    Foley-Fisher, Nathan; McLaughlin, Eoin

    2014-01-01

    We study Ireland´s inheritance of debt following its secession from the United Kingdom at the beginning of the twentieth century. Exploiting structural differences in bonds guaranteed by the UK and Irish governments, we can identify perceived uncertainty about fiscal responsibility in the aftermath of the sovereign breakup. We document that Ireland´s default on intergovernmental payments was an important event. Although payments from the Irish government ceased, the UK government instructed i...

  16. A Default Model of The Non-listed Companies Under Asymmetric Information

    Institute of Scientific and Technical Information of China (English)

    Wang Fake

    2013-01-01

    For the financing difficulties of the non-listed companies, A continuous credit risk model is created which is based on the asymmetric information theory.In the model,the value of the non-listed companies is estimated by the free cash flow,and the loan discussed contains the collateral asset.Based on the model,The default probability,the LGD and the largest company debts are discussed.

  17. Dopamine Transporters in Striatum Correlate with Deactivation in the Default Mode Network during Visuospatial Attention

    OpenAIRE

    Dardo Tomasi; Volkow, Nora D.; Ruiliang Wang; Frank Telang; Gene-Jack Wang; Linda Chang; Thomas Ernst; Fowler, Joanna S.

    2009-01-01

    BACKGROUND: Dopamine and dopamine transporters (DAT, which regulate extracellular dopamine in the brain) are implicated in the modulation of attention but their specific roles are not well understood. Here we hypothesized that dopamine modulates attention by facilitation of brain deactivation in the default mode network (DMN). Thus, higher striatal DAT levels, which would result in an enhanced clearance of dopamine and hence weaker dopamine signals, would be associated to lower deactivation i...

  18. The Comovement of credit default swap, bond and stock markets : an empirical analysis

    OpenAIRE

    Norden, Lars; WEBER, Martin

    2004-01-01

    This paper analyzes the empirical relationship between credit default swap, bond and stock markets during the period 2000-2002. Focusing on the intertemporal comovement, we examine weekly and daily lead-lag relationships in a vector autoregressive model and the adjustment between markets caused by cointegration. First, we find that stock returns lead CDS and bond spread changes. Second, CDS spread changes Granger cause bond spread changes for a higher number of firms than vice versa. Third, t...

  19. An empirical comparison of credit spreads between the bond market and the credit default swap market

    OpenAIRE

    Haibin Zhu

    2004-01-01

    This paper compares the pricing of credit risk in the bond market and the fast-growing credit default swap (CDS) market. The empirical findings confirm the theoretical prediction that bond spreads and CDS spreads move together in the long run. Nevertheless, in the short run this relationship does not always hold. The deviation is largely due to different responses of the two markets to changes in credit conditions. By looking into the dynamic linkages between the two spreads, I find that the ...

  20. Top-down regulation of default mode activity in spatial visual attention

    OpenAIRE

    Wen, Xiaotong; Liu, Yijun; Yao, Li; Ding, Mingzhou

    2013-01-01

    Dorsal anterior cingulate and bilateral anterior insula form a task control network (TCN) whose primary function includes initiating and maintaining task-level cognitive set and exerting top-down regulation of sensorimotor processing. The default mode network (DMN), comprising an anatomically distinct set of cortical areas, mediates introspection and self-referential processes. Resting-state data show that TCN and DMN interact. The functional ramifications of their interaction remain elusive....

  1. Game Analysis of Microfinance Default Risk%小额信贷违约风险的博弈分析

    Institute of Scientific and Technical Information of China (English)

    段霞

    2014-01-01

    Default risk between microfinance institutions and farmers severely restricted the effective operation and sustainable development of microfinance. In this paper, by establishing the static game model and dynamic game model to analyze microfinance risk of default, getting measures of reducing the risk of small credit default, and giving suggestions for preventing microfinance risk of default.%小额信贷机构与农户之间的违约风险严重制约了小额信贷的有效运作与可持续发展。通过建立静态博弈模型及动态博弈模型对小额信贷违约风险进行分析,得到降低小额信贷违约风险的措施,并为防范小额信贷违约风险提出建议。

  2. From default probabilities to credit spreads: credit risk models explain market prices (Keynote Address)

    Science.gov (United States)

    Denzler, Stefan M.; Dacorogna, Michel M.; Muller, Ulrich A.; McNeil, Alexander J.

    2005-05-01

    Credit risk models like Moody's KMV are now well established in the market and give bond managers reliable default probabilities for individual firms. Until now it has been hard to relate those probabilities to the actual credit spreads observed on the market for corporate bonds. Inspired by the existence of scaling laws in financial markets by Dacorogna et al. 2001 and DiMatteo et al. 2005 deviating from the Gaussian behavior, we develop a model that quantitatively links those default probabilities to credit spreads (market prices). The main input quantities to this study are merely industry yield data of different times to maturity and expected default frequencies (EDFs) of Moody's KMV. The empirical results of this paper clearly indicate that the model can be used to calculate approximate credit spreads (market prices) from EDFs, independent of the time to maturity and the industry sector under consideration. Moreover, the model is effective in an out-of-sample setting, it produces consistent results on the European bond market where data are scarce and can be adequately used to approximate credit spreads on the corporate level.

  3. Creativity and the default network: A functional connectivity analysis of the creative brain at rest☆

    Science.gov (United States)

    Beaty, Roger E.; Benedek, Mathias; Wilkins, Robin W.; Jauk, Emanuel; Fink, Andreas; Silvia, Paul J.; Hodges, Donald A.; Koschutnig, Karl; Neubauer, Aljoscha C.

    2014-01-01

    The present research used resting-state functional magnetic resonance imaging (fMRI) to examine whether the ability to generate creative ideas corresponds to differences in the intrinsic organization of functional networks in the brain. We examined the functional connectivity between regions commonly implicated in neuroimaging studies of divergent thinking, including the inferior prefrontal cortex and the core hubs of the default network. Participants were prescreened on a battery of divergent thinking tests and assigned to high- and low-creative groups based on task performance. Seed-based functional connectivity analysis revealed greater connectivity between the left inferior frontal gyrus (IFG) and the entire default mode network in the high-creative group. The right IFG also showed greater functional connectivity with bilateral inferior parietal cortex and the left dorsolateral prefrontal cortex in the high-creative group. The results suggest that the ability to generate creative ideas is characterized by increased functional connectivity between the inferior prefrontal cortex and the default network, pointing to a greater cooperation between brain regions associated with cognitive control and low-level imaginative processes. PMID:25245940

  4. Regularities and discrepancies of credit default swaps: a data science approach through Benford's law

    Science.gov (United States)

    Ausloos, Marcel; Castellano, Rosella; Cerqueti, Roy

    2016-09-01

    In this paper, we search whether the Benford's law is applicable to monitor daily changes in sovereign Credit Default Swaps (CDS) quotes, which are acknowledged to be complex systems of economic content. This test is of paramount importance since the CDS of a country proxy its health and probability to default, being associated to an insurance against the event of its default. We fit the Benford's law to the daily changes in sovereign CDS spreads for 13 European countries, - both inside and outside the European Union and European Monetary Union. Two different tenors for the sovereign CDS contracts are considered: 5 yrs and 10 yrs, - the former being the reference and most liquid one. The time period under investigation is 2008-2015 which includes the period of distress caused by the European sovereign debt crisis. Moreover, (i) an analysis over relevant sub-periods is carried out, (ii) several insights are provided also by implementing the tracking of the Benford's law over moving windows. The main test for checking the conformance to Benford's law is - as usual - the $\\chi^{2}$ test, whose values are presented and discussed for all cases. The analysis is further completed by elaborations based on Chebyshev's distance and Kullback and Leibler's divergence. The results highlight differences by countries and tenors. In particular, these results suggest that liquidity seems to be associated to higher levels of distortion. Greece - representing a peculiar case - shows a very different path with respect to the other European countries.

  5. Reading fiction and reading minds: the role of simulation in the default network.

    Science.gov (United States)

    Tamir, Diana I; Bricker, Andrew B; Dodell-Feder, David; Mitchell, Jason P

    2016-02-01

    Research in psychology has suggested that reading fiction can improve individuals' social-cognitive abilities. Findings from neuroscience show that reading and social cognition both recruit the default network, a network which is known to support our capacity to simulate hypothetical scenes, spaces and mental states. The current research tests the hypothesis that fiction reading enhances social cognition because it serves to exercise the default subnetwork involved in theory of mind. While undergoing functional neuroimaging, participants read literary passages that differed along two dimensions: (i) vivid vs abstract and (ii) social vs non-social. Analyses revealed distinct subnetworks of the default network respond to the two dimensions of interest: the medial temporal lobe subnetwork responded preferentially to vivid passages, with or without social content; the dorsomedial prefrontal cortex (dmPFC) subnetwork responded preferentially to passages with social and abstract content. Analyses also demonstrated that participants who read fiction most often also showed the strongest social cognition performance. Finally, mediation analysis showed that activity in the dmPFC subnetwork in response to the social content mediated this relation, suggesting that the simulation of social content in fiction plays a role in fiction's ability to enhance readers' social cognition.

  6. Analysis on Risk Prevention Mechanism for Farmers’ Default in Small Amount Credit

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Through analysis, it is believed that major reasons for default risks in operation of small amount credit include low management level and vacancy of normative system, vacancy of risk sharing mechanism, rating distortion due to imperfect credit investigation system, and uncertainty of borrower’s credit. On the basis of these, static and dynamic models are established to analyze the prevention mechanism for default risk in small amount credit. It is concluded that we must establish a restriction mechanism during operation of small amount credit as long as three values increase, namely, N (potential loss of bad credit record due to farmers’ default), Q (probability of successful recovery by small amount credit institution), and S (cost of small amount credit institution punishing farmers after successful recovery). Finally, following countermeasures and suggestions are put forward: perfect laws and regulations and credit reward and punishment mechanism for risk management of small amount credit; bring into play proper function of loan officer in small amount credit practice; widely promote rural "Group Credit Union" system.

  7. Reading fiction and reading minds: the role of simulation in the default network.

    Science.gov (United States)

    Tamir, Diana I; Bricker, Andrew B; Dodell-Feder, David; Mitchell, Jason P

    2016-02-01

    Research in psychology has suggested that reading fiction can improve individuals' social-cognitive abilities. Findings from neuroscience show that reading and social cognition both recruit the default network, a network which is known to support our capacity to simulate hypothetical scenes, spaces and mental states. The current research tests the hypothesis that fiction reading enhances social cognition because it serves to exercise the default subnetwork involved in theory of mind. While undergoing functional neuroimaging, participants read literary passages that differed along two dimensions: (i) vivid vs abstract and (ii) social vs non-social. Analyses revealed distinct subnetworks of the default network respond to the two dimensions of interest: the medial temporal lobe subnetwork responded preferentially to vivid passages, with or without social content; the dorsomedial prefrontal cortex (dmPFC) subnetwork responded preferentially to passages with social and abstract content. Analyses also demonstrated that participants who read fiction most often also showed the strongest social cognition performance. Finally, mediation analysis showed that activity in the dmPFC subnetwork in response to the social content mediated this relation, suggesting that the simulation of social content in fiction plays a role in fiction's ability to enhance readers' social cognition. PMID:26342221

  8. Default mode network segregation and social deficits in autism spectrum disorder: Evidence from non-medicated children

    OpenAIRE

    Yerys, Benjamin E.; Gordon, Evan M.; Danielle N. Abrams; Satterthwaite, Theodore D.; Rachel Weinblatt; Jankowski, Kathryn F.; John Strang; Lauren Kenworthy; Gaillard, William D.; Vaidya, Chandan J.

    2015-01-01

    Functional pathology of the default mode network is posited to be central to social-cognitive impairment in autism spectrum disorders (ASD). Altered functional connectivity of the default mode network's midline core may be a potential endophenotype for social deficits in ASD. Generalizability from prior studies is limited by inclusion of medicated participants and by methods favoring restricted examination of network function. This study measured resting-state functional connectivity in 22 8–...

  9. Predictors of defaulting from completion of child immunization in south Ethiopia, May 2008 – A case control study

    OpenAIRE

    Woldie Mirkuzie; Deribew Amare; Tadesse Henoke

    2009-01-01

    Abstract Background Epidemiological investigations of recent outbreaks of vaccine preventable diseases have indicated that incomplete immunization was the major reason for the outbreaks. In Ethiopia, full immunization rate is low and reasons for defaulting from immunization are not studied well. The objective of the study was to identify the predictors of defaulting from completion of child immunization among children between ages 9–23 months in Wonago district, South Ethiopia. Methods Unmatc...

  10. Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide.

    Science.gov (United States)

    Speth, Jana; Speth, Clemens; Kaelen, Mendel; Schloerscheidt, Astrid M; Feilding, Amanda; Nutt, David J; Carhart-Harris, Robin L

    2016-04-01

    This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 μg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured interviews performed shortly after the functional magnetic resonance imaging (fMRI) scans (approximately 2.5 h post-administration). Within each report, specific linguistic references to mental spaces for the past, present and future were identified. Results revealed significantly fewer mental spaces for the past under LSD and this effect correlated with the general intensity of the drug's subjective effects. No differences in the number of mental spaces for the present or future were observed. Consistent with the previously proposed role of the default-mode network (DMN) in autobiographical memory recollection and ruminative thought, decreased resting-state functional connectivity (RSFC) within the DMN correlated with decreased mental time travel to the past. These results are discussed in relation to potential therapeutic applications of LSD and related psychedelics, e.g. in the treatment of depression, for which excessive reflection on one's past, likely mediated by DMN functioning, is symptomatic.

  11. Decreased mental time travel to the past correlates with default-mode network disintegration under lysergic acid diethylamide.

    Science.gov (United States)

    Speth, Jana; Speth, Clemens; Kaelen, Mendel; Schloerscheidt, Astrid M; Feilding, Amanda; Nutt, David J; Carhart-Harris, Robin L

    2016-04-01

    This paper reports on the effects of LSD on mental time travel during spontaneous mentation. Twenty healthy volunteers participated in a placebo-controlled crossover study, incorporating intravenous administration of LSD (75 μg) and placebo (saline) prior to functional magnetic resonance imaging (fMRI). Six independent, blind judges analysed mentation reports acquired during structured interviews performed shortly after the functional magnetic resonance imaging (fMRI) scans (approximately 2.5 h post-administration). Within each report, specific linguistic references to mental spaces for the past, present and future were identified. Results revealed significantly fewer mental spaces for the past under LSD and this effect correlated with the general intensity of the drug's subjective effects. No differences in the number of mental spaces for the present or future were observed. Consistent with the previously proposed role of the default-mode network (DMN) in autobiographical memory recollection and ruminative thought, decreased resting-state functional connectivity (RSFC) within the DMN correlated with decreased mental time travel to the past. These results are discussed in relation to potential therapeutic applications of LSD and related psychedelics, e.g. in the treatment of depression, for which excessive reflection on one's past, likely mediated by DMN functioning, is symptomatic. PMID:26979587

  12. Dissociation of regional activity in default mode network in medication-naive, first-episode somatization disorder.

    Directory of Open Access Journals (Sweden)

    Qinji Su

    Full Text Available BACKGROUND: Patients with somatization disorder (SD have altered neural activity in the brain regions of the default mode network (DMN. However, the regional alteration of the DMN in SD remains unknown. The present study was designed to investigate the regional alterations of the DMN in patients with SD at rest. METHODS: Twenty-five first-episode, medication-naive patients with SD and 28 age-, sex-, education- matched healthy controls underwent a resting-state functional magnetic resonance imaging (fMRI scan. The fractional amplitude of low-frequency fluctuations (fALFF was applied to analyze the data. RESULTS: Patients with SD showed a dissociation pattern of resting-state fALFF in the DMN, with increased fALFF in the bilateral superior medial prefrontal cortex (MPFC, BA8, 9 and decreased fALFF in the left precuneus (PCu, BA7. Furthermore, significantly positive correlation was observed between the z values of the voxels within the bilateral superior MPFC and somatization subscale scores of the Symptom Check List (SCL-90 in patients with SD. CONCLUSIONS: Our findings indicate that there is a dissociation pattern of the anterior and posterior DMN in first-episode, treatment-naive patients with SD. The results provide new insight for the importance of the DMN in the pathophysiology of SD.

  13. The Statistical Relevance and Effect of Assuming Pessimistic Default Overall Thermal Transmittance Coefficients on Dwelling Energy Performance Certification Quality in Ireland

    OpenAIRE

    Ahern, Ciara; Norton, Brian; ENRIGHT, Bernard

    2016-01-01

    In the EU, Energy Performance Certificates (EPCs) are issued for dwellings whenever they are constructed, sold or leased. Where requiring data would be prohibitively costly, nationally applicable default-values for the thermal transmittance coefficients of the building envelope are employed. Use of such worst case default U-values ensure that a poor dwelling does not attain a better energy rating than is merited. In the absence of empirical data in Ireland thermal-default U-values, as in many...

  14. 湖北省随州市艾滋病/肺结核病双重感染患者抗结核治疗与抗病毒治疗效果分析%Therapeutic effect of concurrent anti-tuberculosis and anti-retroviral treatment among TB-HIV co-infected patients

    Institute of Scientific and Technical Information of China (English)

    殷继国; 何卫华; 练祖银; 许亮; 张玉; 余晓凤; 卢全义; 陈丹丹; 黄万春

    2015-01-01

    目的 探讨抗结核药物联合高效抗逆转录病毒药物治疗艾滋病合并肺结核病的近期疗效及不住院治疗管理的可行性.方法 对湖北省随州市确诊的艾滋病合并肺结核病患者(AIDS/TB),在给予高效抗逆转录病毒药物治疗的同时,按照《中国结核病防治规划实施工作指南》指定的抗结核药物治疗方案初治痰涂片阳性(涂阳)和初治痰涂片阴性(涂阴)肺结核治疗方案(2HRZE/4HR),复治涂阳肺结核治疗方案(2 HRZES/6 HRE)给予抗结核药治疗,在治疗期的第2月末、5月末、6月(或8月)末各进行1次痰结核分枝杆菌涂片检查、摄全胸片及临床症状的改善随访调查,治疗前、疗程结束各检查1次CD4+T细胞计数,采用不住院治疗,家庭成员督导为主,村医督导为辅,定期监测随访的治疗管理模式进行管理.结果 疗程结束时临床症状改善达96.97% (32/33),胸部病灶显吸及吸收达到100.00% (33/33),空洞消失达到100.00% (4/4),治愈率86.96% (20/23),总治疗成功率88.89% (32/36),CD4+T细胞计数治疗前、后分别为(174.5±139.7)个/μl、(277.9±142.2)个/μl,差异有统计学意义(P<0.01).结论 抗结核药物联合高效抗逆转录病毒药物治疗艾滋病合并肺结核病,近期疗效明显,能有效地提高AIDS/TB患者生存质量并延长寿命;在条件许可的情况下,尽可能同时进行抗结核与抗病毒治疗,以期达到最佳治疗效果及尽可能地降低病死率;采用不住院治疗,家庭成员督导为主,村医督导为辅,定期监测随访的治疗管理模式,在我国广大农村地区开展抗结核药物联合高效抗逆转录病毒药物治疗艾滋病合并结核病患者是切实可行的.

  15. Estimativas de loss given default em portfólios de crédito simulados

    Directory of Open Access Journals (Sweden)

    Herbert Kimura

    2013-11-01

    Full Text Available O acordo de Basileia II permite que os bancos utilizem modelos internos que sirvam de base para o cálculo dos requisitos mínimos de capital em virtude do nível de exposição ao risco de crédito. Dentre os principais componentes estimados, estão a probabilidade de inadimplência (PD – probability of default, a perda dada a inadimplência (LGD – loss given default e a exposição à inadimplência (EAD – exposure at default. Este estudo tem como objetivo investigar mecanismos de estimação de LGD utilizando modelos de regressão e transformações logit e Beta. Considerando que o mercado brasileiro ainda se encontra em um estágio incipiente na análise de LGD e a disponibilidade de dados de taxas de recuperação é restrita, serão simulados portfólios de crédito por meio de técnicas de Monte Carlo. A dependência entre LGD e as variáveis explicativas da fração de perdas em caso de inadimplência é modelada por meio de cópulas gaussianas e de matrizes doubly stochastic. Os resultados sugerem que a análise de regressão multivariada, usando diversas funções de transformação, possibilita identificar adequadamente as variáveis que explicam a LGD. Mais particularmente, os resultados indicam que o modelo de Hamerle, Knapp e Wildenauer (2009 para estimação de LGD apresenta desempenho superior ao do desempenho do modelo discutido por Gupton e Stein (2005. 

  16. Loss given default determinants in a commercial bank lending: an emerging market case study

    Directory of Open Access Journals (Sweden)

    Jure Poljšak

    2010-06-01

    Full Text Available The purpose of this paper is to analyse the loss given default (LGD determinants in case of a typical loan portfolio consisting of SME loans in a commercial bank operating in one of the quickly developing banking markets, i.e. in Slovenia. Accurate LGD estimates of defaulted bank claims are important for provisioning reserves for credit losses, calculating adequate risk capital and determining fair pricing risky bank loans. While most of the empirical literature in the field concentrates on corporate bond markets to estimate losses in the event of default, we use a unique individual bank data set on SME loan losses. Due to the proprietary nature of data only few studies of this kind have been published so far and to our knowledge none of them covers the Eastern European banking markets. In the first stage of the analysis we estimate the LGD variable by applying the discounted cash flow approach, while in the second stage we analyse its determinants by using the ordinal regression analysis. Our findings suggest that reliable LGD estimates can be produced by discounting expected loan related future cash flows and that explanatory factors, such as type of collateral, type of industrial sector, last available loan rating, size of the debt and loan maturity satisfactorily explicate variability of the LGD variable in the specific banking market. All the results are not only relevant to the impairment policy determination and capital adequacy calculation in the specific bank, but also to the evaluation of SME loans characteristics in developing markets.

  17. The fundamental theorem of asset pricing under default and collateral in finite discrete time

    Science.gov (United States)

    Alvarez-Samaniego, Borys; Orrillo, Jaime

    2006-08-01

    We consider a financial market where time and uncertainty are modeled by a finite event-tree. The event-tree has a length of N, a unique initial node at the initial date, and a continuum of branches at each node of the tree. Prices and returns of J assets are modeled, respectively, by a R2JxR2J-valued stochastic process . In this framework we prove a version of the Fundamental Theorem of Asset Pricing which applies to defaultable securities backed by exogenous collateral suffering a contingent linear depreciation.

  18. Discourse norms as default rules: structuring corporate speech to multiple stakeholders.

    Science.gov (United States)

    Yosifon, David G

    2011-01-01

    This Article analyzes corporate speech problems through the framework of corporate law. The focus here is on the "discourse norms" that regulate corporate speech to various corporate stakeholders, including shareholders, workers, and consumers. I argue that these "discourse norms" should be understood as default terms in the "nexus-of-contracts" that comprises the corporation. Having reviewed the failure of corporate law as it bears on the interests of non-shareholding stakeholders such as workers and consumers, I urge the adoption of prescriptive discourse norms as an approach to reforming corporate governance in a socially useful manner. PMID:21847901

  19. Discourse norms as default rules: structuring corporate speech to multiple stakeholders.

    Science.gov (United States)

    Yosifon, David G

    2011-01-01

    This Article analyzes corporate speech problems through the framework of corporate law. The focus here is on the "discourse norms" that regulate corporate speech to various corporate stakeholders, including shareholders, workers, and consumers. I argue that these "discourse norms" should be understood as default terms in the "nexus-of-contracts" that comprises the corporation. Having reviewed the failure of corporate law as it bears on the interests of non-shareholding stakeholders such as workers and consumers, I urge the adoption of prescriptive discourse norms as an approach to reforming corporate governance in a socially useful manner.

  20. Essays on capital structure, debt maturity, trade credit, and default probability

    OpenAIRE

    Hol, Suzan

    2004-01-01

    To finance investments, a firm needs to decide which sources are to be used to attract funds; that is how the financial structure of the firm should be. The main subjects of this thesis are how the firm’s financial structure is determined and how the chosen financial structure affects the firm’s probability of default. The thesis consists of five essays studying the financial structure of firms and one popular scientific paper on financial behavior.In the first paper, a theoretical model is d...

  1. Benchmark Simulation Model No 2 – finalisation of plant layout and default control strategy

    DEFF Research Database (Denmark)

    Nopens, I.; Benedetti, L.; Jeppsson, U.;

    2010-01-01

    The COST/IWA Benchmark Simulation Model No 1 (BSM1) has been available for almost a decade. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the research work related to the benchmark simulation models has resulted in...... be evaluated in a realistic fashion in the one week BSM1 evaluation period. In this paper, the finalised plant layout is summarised and, as was done for BSM1, a default control strategy is proposed. A demonstration of how BSM2 can be used to evaluate control strategies is also given....

  2. Clinical characteristic, diagnosis and effectiveness of treatment of tuberculosis in HIV-infected patients in the Saratov region

    Directory of Open Access Journals (Sweden)

    T. I. Morozova

    2016-01-01

    Full Text Available Aim: evaluate the clinical manifestations, efficacy of microbiologicaldiagnosis and results of treatment of patients with tuberculosis (TB in combination with HIV (TB/HIV, residing in the territory of the Saratov region.Materials and methods: analyzed the medical records (hospital records, medical history, personal record cards TB/HIV, 130 patients coinfected with TB/HIV who were on treatment in TB facilities of Saratov region in 2014.Results: it was found that the combination of TB and HIV infection was more common in men (71,5% aged 30–39 years, mostly (75,4% residents of large cities. TB in 64,6% of cases develop on the background of existing HIV infection with disease duration from 1 to 18 years. The dominant forms of TB were infiltrative – 50,8% and disseminated – 25,4% with high levels of multidrug resistance (MDR – 25% and polyresistance – 17,3%. Efficiency a course of treatment of ТВ which was completed in 2014 year amounted to 41,5% and was higher in the group of patients in which treatment with anti-tuberculosis therapy is used antiretroviral therapy (ARVT – 49,3% versus 30,9% without ARVT, p = 0,0416. It was found increase of CD4 cell counts after treatment in patients TB/HIV, which, together with anti-tuberculosis therapy received ARVT 301 ± 45 cells/microliter vs. 202,3 ± 32 cells/microliter in patients without ARVT, p=0,0416.Conclusion: determined that TB in patients with HIV infection characterized by severe course of the process with low efficiency of treatment and high MDR, which requires the strengthening of measures to control the spread of TB in these patients. 

  3. OVERVIEW OF THE RELEVANT INDICATORS OF DEFAULTED AND NON-DEFAULTED COMPANIES AND POSSIBILITIES OF IMPROVEMENT FOR THE RATING SYSTEMS USED BY THE ROMANIAN COMMERCIAL BANKS

    Directory of Open Access Journals (Sweden)

    Kovacs Ildiko

    2011-12-01

    Full Text Available Since the beginning of the financial and economic crises many news came to light which discussed the increasing number of non-performing loans, and the fact that as a result of the company break-downs, the bank portfolios have also gone worse and worse. In this paper our goal is to find out which internal factors influence the solvency of a company, therefore, to point out the weaknesses of the current Romanian rating systems, which as we will see, do not take into only relevant criteria when according a loan to a company. In order to conduct this study, we choose 18 indicators from several categories to predict bankruptcy. Some of the indicators mentioned above are really common in the international and the Romanian literature (e.g. ROA, ROE, ROS, assets turnover ratio, some of them are less. On a sample of 3000 Romanian companies we use the T-test statistical method to find out if an indicator is significant or not. The sample consists of companies (defaulted and non-defaulted as well which have presented their financial statements (balance, profit and loss account between 1999 and 2008. For each company a set of 18 financial indicators was calculated, but the results obtained show that only 8 of them is significant in predicting bankruptcy: ROA, assets turnover ratio, equity/total assets, general leverage, current assets to total assets, cash to total assets, total assets and sales. In the next step, by analyzing the obligatory forms used in credit lending, we conclude which indicators are used by different Romanian commercial banks. We found that only four out of seven banks calculate all of the significant indicators identified in the first part of the paper. Finally, we made a proposal about which quantitative indicators should the banks use to minimize the credit losses and to avoid the overdue payments. In addition, we consider that the banks should pay attention to the qualitative factors as well to effectively filter out non

  4. Is there Needed an Industry Approach on Corporate Default Risk? Case Study on Companies Listed on Romanian Stock Exchange

    Directory of Open Access Journals (Sweden)

    Cristina Maria Triandafil

    2009-02-01

    Full Text Available This paper focuses on applying Black and Scholes structural approach on credit risk in the case of the companies listed on Romanian Stock Exchange. We conduct a case-study on 35 companies belonging to five industries (energetic, materials, chemistry, pharmaceuticals, equipments during a period of 10 years in order to highlight out default point/threshold and its essential factors evolution across industries. Research approach is concentrated also on the specific characteristics of the Romanian capital market (especially in terms of illiquidity and lack of transparency additional costs, macroeconomic environment and corporate finance decision process. We compute default point from the perspective of the arbitrage between assets and leverage; in accordance with the most recent theories on specific features corporate default within emerging countries (Galytskyy, 2006, a key element will be represented by the assets volatility which will be correlated with the country risk premium in order to highlight out a potential macroeconomic impact on corporate failure.

  5. A unified 3D default space consciousness model combining neurological and physiological processes that underlie conscious experience

    Directory of Open Access Journals (Sweden)

    Ravinder eJerath

    2015-08-01

    Full Text Available The Global Workspace Theory and Information Integration Theory are two of the most currently accepted consciousness models; however, these models do not address many aspects of conscious experience. We compare these models to our previously proposed consciousness model in which the thalamus fills-in processed sensory information from corticothalamic feedback loops within a proposed 3D default space, resulting in the recreation of the internal and external worlds within the mind. This 3D default space is composed of all cells of the body, which communicate via gap junctions and electrical potentials to create this unified space. We use 3D illustrations to explain how both visual and non-visual sensory information is filled-in within this dynamic space, creating a unified seamless conscious experience. This neural sensory memory space is likely generated by baseline neural oscillatory activity from the default mode network, other salient networks, brainstem, and reticular activating system.

  6. Hawkes-diffusion process and the conditional probability of defaults in the Eurozone

    Science.gov (United States)

    Kim, Jungmu; Park, Yuen Jung; Ryu, Doojin

    2016-05-01

    This study examines market information embedded in the European sovereign CDS (credit default swap) market by analyzing the sovereign CDSs of 13 Eurozone countries from January 1, 2008, to February 29, 2012, which includes the recent Eurozone debt crisis period. We design the conditional probability of defaults for the CDS prices based on the Hawkes-diffusion process and obtain the theoretical prices of CDS indexes. To estimate the model parameters, we calibrate the model prices to empirical prices obtained from individual sovereign CDS term structure data. The estimated parameters clearly explain both cross-sectional and time-series data. Our empirical results show that the probability of a huge loss event sharply increased during the Eurozone debt crisis, indicating a contagion effect. Even countries with strong and stable economies, such as Germany and France, suffered from the contagion effect. We also find that the probability of small events is sensitive to the state of the economy, spiking several times due to the global financial crisis and the Greek government debt crisis.

  7. Resting-state functional connectivity of the default mode network associated with happiness.

    Science.gov (United States)

    Luo, Yangmei; Kong, Feng; Qi, Senqing; You, Xuqun; Huang, Xiting

    2016-03-01

    Happiness refers to people's cognitive and affective evaluation of their life. Why are some people happier than others? One reason might be that unhappy people are prone to ruminate more than happy people. The default mode network (DMN) is normally active during rest and is implicated in rumination. We hypothesized that unhappiness may be associated with increased default-mode functional connectivity during rest, including the medial prefrontal cortex (MPFC), posterior cingulate cortex (PCC) and inferior parietal lobule (IPL). The hyperconnectivity of these areas may be associated with higher levels of rumination. One hundred forty-eight healthy participants underwent a resting-state fMRI scan. A group-independent component analysis identified the DMNs. Results indicated increased functional connectivity in the DMN was associated with lower levels of happiness. Specifically, relative to happy people, unhappy people exhibited greater functional connectivity in the anterior medial cortex (bilateral MPFC), posterior medial cortex regions (bilateral PCC) and posterior parietal cortex (left IPL). Moreover, the increased functional connectivity of the MPFC, PCC and IPL, correlated positively with the inclination to ruminate. These results highlight the important role of the DMN in the neural correlates of happiness, and suggest that rumination may play an important role in people's perceived happiness.

  8. Unilateral deafness in children affects development of multi-modal modulation and default mode networks

    Directory of Open Access Journals (Sweden)

    Vincent eSchmithorst

    2014-03-01

    Full Text Available Monaural auditory input due to congenital or acquired unilateral hearing loss (UHL may have neurobiological effects on the developing brain. Using fMRI, we investigated the effect of UHL on the development of functional brain networks used for cross-modal processing. Children ages 7-12 with moderate or greater unilateral hearing loss of sensorineural origin (UHL-SN; N = 21 and normal-hearing controls (N = 23 performed an fMRI-compatible adaptation of the Token Test involving listening to a sentence such as touched the small green circle and the large blue square and simultaneously viewing an arrow touching colored shapes on a video. Children with right or severe-to-profound UHL-SN displayed smaller activation in a region encompassing the right inferior temporal, middle temporal, and middle occipital gyrus (BA 19/37/39, evidencing differences due to monaural hearing in cross-modal modulation of the visual processing pathway. Children with UHL-SN displayed increased activation in the left posterior superior temporal gyrus, likely the result either of more effortful low-level processing of auditory stimuli or differences in cross-modal modulation of the auditory processing pathway. Additionally, children with UHL-SN displayed reduced deactivation of anterior and posterior regions of the default mode network. Results suggest that monaural hearing affects the development of brain networks related to cross-modal sensory processing and the regulation of the default network during processing of spoken language.

  9. Unilateral deafness in children affects development of multi-modal modulation and default mode networks.

    Science.gov (United States)

    Schmithorst, Vincent J; Plante, Elena; Holland, Scott

    2014-01-01

    Monaural auditory input due to congenital or acquired unilateral hearing loss (UHL) may have neurobiological effects on the developing brain. Using functional magnetic resonance imaging (fMRI), we investigated the effect of UHL on the development of functional brain networks used for cross-modal processing. Children ages 7-12 with moderate or greater unilateral hearing loss of sensorineural origin (UHL-SN; N = 21) and normal-hearing controls (N = 23) performed an fMRI-compatible adaptation of the Token Test involving listening to a sentence such as "touched the small green circle and the large blue square" and simultaneously viewing an arrow touching colored shapes on a video. Children with right or severe-to-profound UHL-SN displayed smaller activation in a region encompassing the right inferior temporal, middle temporal, and middle occipital gyrus (BA 19/37/39), evidencing differences due to monaural hearing in cross-modal modulation of the visual processing pathway. Children with UHL-SN displayed increased activation in the left posterior superior temporal gyrus, likely the result either of more effortful low-level processing of auditory stimuli or differences in cross-modal modulation of the auditory processing pathway. Additionally, children with UHL-SN displayed reduced deactivation of anterior and posterior regions of the default mode network. Results suggest that monaural hearing affects the development of brain networks related to cross-modal sensory processing and the regulation of the default network during processing of spoken language. PMID:24723873

  10. Prestimulus default mode activity influences depth of processing and recognition in an emotional memory task.

    Science.gov (United States)

    Soravia, Leila M; Witmer, Joëlle S; Schwab, Simon; Nakataki, Masahito; Dierks, Thomas; Wiest, Roland; Henke, Katharina; Federspiel, Andrea; Jann, Kay

    2016-03-01

    Low self-referential thoughts are associated with better concentration, which leads to deeper encoding and increases learning and subsequent retrieval. There is evidence that being engaged in externally rather than internally focused tasks is related to low neural activity in the default mode network (DMN) promoting open mind and the deep elaboration of new information. Thus, reduced DMN activity should lead to enhanced concentration, comprehensive stimulus evaluation including emotional categorization, deeper stimulus processing, and better long-term retention over one whole week. In this fMRI study, we investigated brain activation preceding and during incidental encoding of emotional pictures and on subsequent recognition performance. During fMRI, 24 subjects were exposed to 80 pictures of different emotional valence and subsequently asked to complete an online recognition task one week later. Results indicate that neural activity within the medial temporal lobes during encoding predicts subsequent memory performance. Moreover, a low activity of the default mode network preceding incidental encoding leads to slightly better recognition performance independent of the emotional perception of a picture. The findings indicate that the suppression of internally-oriented thoughts leads to a more comprehensive and thorough evaluation of a stimulus and its emotional valence. Reduced activation of the DMN prior to stimulus onset is associated with deeper encoding and enhanced consolidation and retrieval performance even one week later. Even small prestimulus lapses of attention influence consolidation and subsequent recognition performance. PMID:26663662

  11. Fiscally Unsustainable Social Welfare, Untenable Housing Solutions and the Mortgage Default Ratio in South Africa

    Directory of Open Access Journals (Sweden)

    Vuyisani Vuyisani Moss

    2013-10-01

    Full Text Available This article reflects on social welfare system and governance of housingmarkets from an end-user perspective. The article critically analyses the wayin which social welfare has correlated to unsustainable development and createdself entitlement behaviours and attitudes in the South African low incomehousing market.  The phenomenon wasdemonstrable by empirical research whose findings confirmed an existence of anassociation between a fully subsidized social housing model (as underpinned bySouth Africa’s social welfare and propensity to default on mortgages.  The study found that the risk of default byhomeowners in the low income housing market in South Africa is influenced bygovernment’s housing grant model. In other words, the research established thatthe principle of servicing a mortgaged starter property (that is almost similarto a government free house by both structure and design is not universallyaccepted by homeowners of these mortgaged houses.  The unintended consequences are that thesystem has created indefinite expectations that potentially could; (i erodethe country’s balance sheet; (ii add to non-payment behaviour; (iii pressurizethe economic and credit systems; (iv propagate entitlement attitudes andmindsets; (v create social instability and (v widened the country’s balanceof payment deficits.

  12. Definition and characterization of an extended social-affective default network.

    Science.gov (United States)

    Amft, Maren; Bzdok, Danilo; Laird, Angela R; Fox, Peter T; Schilbach, Leonhard; Eickhoff, Simon B

    2015-03-01

    Recent evidence suggests considerable overlap between the default mode network (DMN) and regions involved in social, affective and introspective processes. We considered these overlapping regions as the social-affective part of the DMN. In this study, we established a robust mapping of the underlying brain network formed by these regions and those strongly connected to them (the extended social-affective default network). We first seeded meta-analytic connectivity modeling and resting-state analyses in the meta-analytically defined DMN regions that showed statistical overlap with regions associated with social and affective processing. Consensus connectivity of each seed was subsequently delineated by a conjunction across both connectivity analyses. We then functionally characterized the ensuing regions and performed several cluster analyses. Among the identified regions, the amygdala/hippocampus formed a cluster associated with emotional processes and memory functions. The ventral striatum, anterior cingulum, subgenual cingulum and ventromedial prefrontal cortex formed a heterogeneous subgroup associated with motivation, reward and cognitive modulation of affect. Posterior cingulum/precuneus and dorsomedial prefrontal cortex were associated with mentalizing, self-reference and autobiographic information. The cluster formed by the temporo-parietal junction and anterior middle temporal sulcus/gyrus was associated with language and social cognition. Taken together, the current work highlights a robustly interconnected network that may be central to introspective, socio-affective, that is, self- and other-related mental processes. PMID:24399179

  13. TREATMENT OUTCOMES IN PATIENTS TREATED UNDER RNTCP IN KARAD TUBERCULOSIS UNIT

    Directory of Open Access Journals (Sweden)

    Vandana

    2014-12-01

    Full Text Available BACKGROUND: The Revised National Tuberculosis Control Programme (RNTCP, India. OBJECTIVE: To study the treatment outcomes in patients treated under RNTCP &causes of defaulted, death, failure among them. MATERIAL & METHODS: This study was conducted in Karad Tuberculosis Unit (TU, Satara District, Maharashtra. Under Karad Tuberculosis Unit there were nine PHCs, Sub District Hospital and Krishna Hospital, six Designated Microscopy Centre’s (DMC, three Integrated Counseling and Testing Centre’s (ICTC – KH, SDH and Undale. All patients registered during January2008 to June 2009 i.e.806 were the study subjects. Before commencement of study permission of District Tuberculosis Officer (DTO was taken. STUDY TYPE: Longitudinal (Prospective Study. STUDY PLAN: Patients were interviewed using pre-tested semi structured questionnaires at their residence at the start of treatment, after completion of intensive phase and cohort was further followed up for approximately six months. RESULTS & OBSERVATIONS: Out of 233 new sputum smear positive (NSP patients, 214 had their sputum smear negative at the end of Intensive phase (IP; hence sputum conversion rate was 91.84% in present study. We found that233newsputum smear positive cases out of which 187 were cured. Thus the cure rate was 80.2%.Out of which 506 smear negative and extra pulmonary patients 462 completed treatment hence treatment completion rate was 91.30%. Out of 233 new smear sputum positive cases, 23 died thus death rate was 9.8%, 5 patients were treatment failure thus the failure rate was 2.1 %. 12 patients defaulted the treatment thus defaulted rate was5.15%.Due to tuberculosis 22 (2.7% patients died, 27 (3.3% due to HIV, 17 (2.1% defaulted due to migration, 5 (0.6% defaulted due to addiction of alcohol, 3 (0.4% defaulted due to not relief from symptoms, 1 (0.1% defaulted due to adverse reaction.16 (2% failed in due to initial heavy bacillary load. CONCLUSION: It is observed that our regimens

  14. Default Mode and Executive Networks Areas: Association with the Serial Order in Divergent Thinking

    Science.gov (United States)

    Heinonen, Jarmo; Numminen, Jussi; Hlushchuk, Yevhen; Antell, Henrik; Taatila, Vesa; Suomala, Jyrki

    2016-01-01

    Scientific findings have suggested a two-fold structure of the cognitive process. By using the heuristic thinking mode, people automatically process information that tends to be invariant across days, whereas by using the explicit thinking mode people explicitly process information that tends to be variant compared to typical previously learned information patterns. Previous studies on creativity found an association between creativity and the brain regions in the prefrontal cortex, the anterior cingulate cortex, the default mode network and the executive network. However, which neural networks contribute to the explicit mode of thinking during idea generation remains an open question. We employed an fMRI paradigm to examine which brain regions were activated when participants (n = 16) mentally generated alternative uses for everyday objects. Most previous creativity studies required participants to verbalize responses during idea generation, whereas in this study participants produced mental alternatives without verbalizing. This study found activation in the left anterior insula when contrasting idea generation and object identification. This finding suggests that the insula (part of the brain’s salience network) plays a role in facilitating both the central executive and default mode networks to activate idea generation. We also investigated closely the effect of the serial order of idea being generated on brain responses: The amplitude of fMRI responses correlated positively with the serial order of idea being generated in the anterior cingulate cortex, which is part of the central executive network. Positive correlation with the serial order was also observed in the regions typically assigned to the default mode network: the precuneus/cuneus, inferior parietal lobule and posterior cingulate cortex. These networks support the explicit mode of thinking and help the individual to convert conventional mental models to new ones. The serial order correlated

  15. Default Mode and Executive Networks Areas: Association with the Serial Order in Divergent Thinking.

    Science.gov (United States)

    Heinonen, Jarmo; Numminen, Jussi; Hlushchuk, Yevhen; Antell, Henrik; Taatila, Vesa; Suomala, Jyrki

    2016-01-01

    Scientific findings have suggested a two-fold structure of the cognitive process. By using the heuristic thinking mode, people automatically process information that tends to be invariant across days, whereas by using the explicit thinking mode people explicitly process information that tends to be variant compared to typical previously learned information patterns. Previous studies on creativity found an association between creativity and the brain regions in the prefrontal cortex, the anterior cingulate cortex, the default mode network and the executive network. However, which neural networks contribute to the explicit mode of thinking during idea generation remains an open question. We employed an fMRI paradigm to examine which brain regions were activated when participants (n = 16) mentally generated alternative uses for everyday objects. Most previous creativity studies required participants to verbalize responses during idea generation, whereas in this study participants produced mental alternatives without verbalizing. This study found activation in the left anterior insula when contrasting idea generation and object identification. This finding suggests that the insula (part of the brain's salience network) plays a role in facilitating both the central executive and default mode networks to activate idea generation. We also investigated closely the effect of the serial order of idea being generated on brain responses: The amplitude of fMRI responses correlated positively with the serial order of idea being generated in the anterior cingulate cortex, which is part of the central executive network. Positive correlation with the serial order was also observed in the regions typically assigned to the default mode network: the precuneus/cuneus, inferior parietal lobule and posterior cingulate cortex. These networks support the explicit mode of thinking and help the individual to convert conventional mental models to new ones. The serial order correlated

  16. A compilation of radionuclide transfer factors for the plant, meat, milk, and aquatic food pathways and the suggested default values for the RESRAD code

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.Y.; Biwer, B.M.; Yu, C.

    1993-08-01

    The ongoing development and revision of the RESRAD computer code at Argonne National Laboratory requires update of radionuclide transfer factors for the plant, meat, milk, and aquatic food pathways. Default values for these transfer factors used in published radiological assessment reports are compiled and compared with values used in RESRAD. The differences among the reported default values used in different radiological assessment codes and reports are also discussed. In data comparisons, values used in more recent reports are given more weight because more recent experimental work tends to be conducted under better-defined laboratory or field conditions. A new default value is suggested for RESRAD if one of the following conditions is met: (1) values used in recent reports are an order of magnitude higher or lower than the default value currently used in RESRAD, or (2) the same default value is used in several recent radiological assessment reports.

  17. Impaired language function in generalized epilepsy: inadequate suppression of the default mode network.

    Science.gov (United States)

    Gauffin, Helena; van Ettinger-Veenstra, Helene; Landtblom, Anne-Marie; Ulrici, Daniel; McAllister, Anita; Karlsson, Thomas; Engström, Maria

    2013-07-01

    We aimed to study the effect of a potential default mode network (DMN) dysfunction on language performance in epilepsy. Language dysfunction in focal epilepsy has previously been connected to brain damage in language-associated cortical areas. In this work, we studied generalized epilepsy (GE) without focal brain damage to see if the language function was impaired. We used functional magnetic resonance imaging (fMRI) to investigate if the DMN was involved. Eleven persons with GE and 28 healthy controls were examined with fMRI during a sentence-reading task. We demonstrated impaired language function, reduced suppression of DMN, and, specifically, an inadequate suppression of activation in the left anterior temporal lobe and the posterior cingulate cortex, as well as an aberrant activation in the right hippocampal formation. Our results highlight the presence of language decline in people with epilepsy of not only focal but also generalized origin. PMID:23648277

  18. A new integrative model of cerebral activation, deactivation and default mode function in Alzheimer's disease

    International Nuclear Information System (INIS)

    Functional imaging methods such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) allow in vivo assessment of cerebral metabolism at rest and cerebral responses to cognitive stimuli. Activation studies with different cognitive tasks have deepened the understanding of underlying pathology leading to Alzheimer disease (AD) and how the brain reacts to and potentially compensates the imposed damage inflicted by this disease. The aim of this manuscript study was to summarize current findings of activation studies in healthy people at risk for AD, in people with mild cognitive impairment (MCI) as a possible progenitor of AD and finally in patients with manifest AD, adding recent results about impaired deactivation abilities and default mode function in AD. A new comprehensive model will be introduced integrating these heterogeneous findings and explaining their impact on cognitive performance. (orig.)

  19. Does Central Bank Quality Determine Sovereign Ratings and Credit Default Swap Spreads: Evidence from the World?

    Directory of Open Access Journals (Sweden)

    Ramlall Indranarain

    2016-09-01

    Full Text Available This study innovates from prior research which focuses on the determinants of sovereign ratings and credit default swap spreads for a large sample of countries by incorporating the quality of central banks, let alone refined proxies. Findings show that the explanatory power of both sovereign ratings and CDS spreads model improve by a hefty 11 percent in case of sovereign ratings and 6 to 9 percent in the case of CDS spreads when central bank quality is incorporated. Such a finding bolters the notion that institutional quality does play a preponderant role when it comes to assessing country risk, making it a systematic component of institutional quality. The effect of labour participation implies that countries buffeted by stronger effects of an ageing population have greater propensity of increases in CDS spreads. Evidence is also found as to the driving dynamics of CDS spreads and sovereign ratings to be distinct. Our results hold robust post tackling for endogeneity problem.

  20. Optimal pricing of default customers in electrical distribution systems: Effect behavior performance of demand response models

    International Nuclear Information System (INIS)

    The response of a non-linear mathematical model is analyzed for the calculation of the optimal prices for electricity assuming default customers under different scenarios and using five different mathematical functions for the consumer response: linear, hyperbolic, potential, logarithmic and exponential. The mathematical functions are defined to simulate the hourly changes in the consumer response according to the load level, the price of electricity, and also depending on the elasticity at every hour. The behavior of the optimization model is evaluated separately under two different objective functions: the profit of the electric utility and the social welfare. The optimal prices as well as the served load are calculated for two different operation schemes: in an hourly basis and also assuming a single constant price for the 24 h of the day. Results obtained by the optimization model are presented and compared for the five different consumer load functions. (author)

  1. Default Mode Network Activity Predicts Early Memory Decline in Healthy Young Adults Aged 18-31.

    Science.gov (United States)

    Nelson, Steven M; Savalia, Neil K; Fishell, Andrew K; Gilmore, Adrian W; Zou, Fan; Balota, David A; McDermott, Kathleen B

    2016-08-01

    Functional magnetic resonance imaging (fMRI) research conducted in healthy young adults is typically done with the assumption that this sample is largely homogeneous. However, studies from cognitive psychology suggest that long-term memory and attentional control begin to diminish in the third decade of life. Here, 100 participants between the ages of 18 and 31 learned Lithuanian translations of English words in an individual differences study using fMRI. Long-term memory ability was operationalized for each participant by deriving a memory score from 3 convergent measures. Age of participant predicted memory score in this cohort. In addition, degree of deactivation during initial encoding in a set of regions occurring largely in the default mode network (DMN) predicted both age and memory score. The current study demonstrates that early memory decline may partially be accounted for by failure to modulate activity in the DMN.

  2. Default Mode Network Activity Predicts Early Memory Decline in Healthy Young Adults Aged 18-31.

    Science.gov (United States)

    Nelson, Steven M; Savalia, Neil K; Fishell, Andrew K; Gilmore, Adrian W; Zou, Fan; Balota, David A; McDermott, Kathleen B

    2016-08-01

    Functional magnetic resonance imaging (fMRI) research conducted in healthy young adults is typically done with the assumption that this sample is largely homogeneous. However, studies from cognitive psychology suggest that long-term memory and attentional control begin to diminish in the third decade of life. Here, 100 participants between the ages of 18 and 31 learned Lithuanian translations of English words in an individual differences study using fMRI. Long-term memory ability was operationalized for each participant by deriving a memory score from 3 convergent measures. Age of participant predicted memory score in this cohort. In addition, degree of deactivation during initial encoding in a set of regions occurring largely in the default mode network (DMN) predicted both age and memory score. The current study demonstrates that early memory decline may partially be accounted for by failure to modulate activity in the DMN. PMID:26209847

  3. Default and rational persuasion of the judge Revelia e persuasão racional do juiz

    Directory of Open Access Journals (Sweden)

    Lourival José de Oliveira

    2005-12-01

    Full Text Available It checks the borders of the presumption of facts contained in the initial petition when lacks seasonable contestation with the observance of legal formalities. Seen as an objective fact, the default will occur when the defendant stays inert at the processual moment offered to him to adduce his reasons to resist the request of the prosecutor, what doesn’t necessary implies in its procedure. However, the default not always unleashes its effects, that are classified as material or processual, consisting in the presumption of the veracity of the facts pleaded by the prosecutor in his initial petition and the lack of need of notification the default for the processual acts that follows. The presumption in default is relative, it means that, its effects circumscribing verisimilar facts and consistent with the other evidences that lie in the lawsuit, what goes to the need of the material direction and not only the formal side by the judge as a way to find the fair composition of the litigation, there so attending the social finalities of the process effectively inserted in the Democratic State of Law. Coming to the conclusion that shall exteriorized in the explaining of the decision the coherence of fatidic bases and juridical ones, containing all the prominent points of the suit, therefore attending the principle of the rational persuasion, resulting in a full jurisdictional tutelage, under the penalty of nullity of the law suit due to the lack of motivation of the sentence.Verifica os limites da presunção dos fatos contidos na petição inicial quando da ausência de contestação tempestiva e com a observância das formalidades legais. Vista como um fato objetivo, a revelia ocorrerá quando o réu queda-se inerte no momento processual em que lhe é facultado aduzir suas razões de resistência à demanda do autor, o que não implica necessariamente na sua procedência. Contudo, a revelia nem sempre desencadeia os seus efeitos, que s

  4. PTEN: a default gate-keeping tumor suppressor with a versatile tail

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The tumor suppressor PTEN controls a variety of biological processes including cell proliferation, growth, migration, and death. As a master cellular regulator, PTEN itself is also subjected to deliberated regulation to ensure its proper function. Defects in PTEN regulation have a profound impact on carcinogenesis. In this review, we briefly discuss recent advances concerning PTEN regulation and how such knowledge facilitates our understanding and further exploration of PTEN biology. The carboxyl-tail of PTEN, which appears to be associated with multiple types of posttranslational regulation, will be under detailed scrutiny. Further, a comparative analysis of PTEN and p53 suggests while p53 needs to be activated to suppress tumorigenesis (a dormant gatekeeper), PTEN is probably a constitutive surveillant against cancer development, thus a default gatekeeper.

  5. Coactivation of the Default Mode Network regions and Working Memory Network regions during task preparation.

    Science.gov (United States)

    Koshino, Hideya; Minamoto, Takehiro; Yaoi, Ken; Osaka, Mariko; Osaka, Naoyuki

    2014-01-01

    The Default Mode Network (DMN) regions exhibit deactivation during a wide variety of resource demanding tasks. However, recent brain imaging studies reported that they also show activation during various cognitive activities. In addition, studies have found a negative correlation between the DMN and the working memory network (WMN). Here, we investigated activity in the DMN and WMN regions during preparation and execution phases of a verbal working memory task. Results showed that the core DMN regions, including the medial prefrontal cortex and posterior cingulate cortex, and WMN regions were activated during preparation. During execution, however, the WMN regions were activated but the DMN regions were deactivated. The results suggest that activation of these network regions is affected by allocation of attentional resources to the task relevant regions due to task demands. This study extends our previous results by showing that the core DMN regions exhibit activation during task preparation and deactivation during task execution. PMID:25092432

  6. Acupuncture Modulates the Functional Connectivity of the Default Mode Network in Stroke Patients

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    2014-01-01

    Full Text Available Abundant evidence from previous fMRI studies on acupuncture has revealed significant modulatory effects at widespread brain regions. However, few reports on the modulation to the default mode network (DMN of stroke patients have been investigated in the field of acupuncture. To study the modulatory effects of acupuncture on the DMN of stroke patients, eight right hemispheric infarction and stable ischemic stroke patients and ten healthy subjects were recruited to undergo resting state fMRI scanning before and after acupuncture stimulation. Functional connectivity analysis was applied with the bilateral posterior cingulate cortices chosen as the seed regions. The main finding demonstrated that the interregional interactions between the ACC and PCC especially enhanced after acupuncture at GB34 in stroke patients, compared with healthy controls. The results indicated that the possible mechanisms of the modulatory effects of acupuncture on the DMN of stroke patients could be interpreted in terms of cognitive ability and motor function recovery.

  7. Childhood poverty and stress reactivity are associated with aberrant functional connectivity in default mode network.

    Science.gov (United States)

    Sripada, Rebecca K; Swain, James E; Evans, Gary W; Welsh, Robert C; Liberzon, Israel

    2014-08-01

    Convergent research suggests that childhood poverty is associated with perturbation in the stress response system. This might extend to aberrations in the connectivity of large-scale brain networks, which subserve key cognitive and emotional functions. Resting-state brain activity was measured in adults with a documented history of childhood poverty (n=26) and matched controls from middle-income families (n=26). Participants also underwent a standard laboratory social stress test and provided saliva samples for cortisol assay. Childhood poverty was associated with reduced default mode network (DMN) connectivity. This, in turn, was associated with higher cortisol levels in anticipation of social stress. These results suggest a possible brain basis for exaggerated stress sensitivity in low-income individuals. Alterations in DMN may be associated with less efficient cognitive processing or greater risk for development of stress-related psychopathology among individuals who experienced the adversity of chronic childhood poverty.

  8. 34 CFR 668.184 - Determining cohort default rates for institutions that have undergone a change in status.

    Science.gov (United States)

    2010-07-01

    ... applicable to the other institution under §§ 668.185 and 668.189. (b) Acquisition or merger of institutions... participated independently in the Title IV, HEA programs immediately before the acquisition or merger— (1) For the cohort default rates published before the date of the acquisition or merger, your cohort...

  9. 34 CFR 668.203 - Determining cohort default rates for institutions that have undergone a change in status.

    Science.gov (United States)

    2010-07-01

    ... applicable to the other institution under §§ 668.204 and 668.208. (b) Acquisition or merger of institutions... participated independently in the Title IV, HEA programs immediately before the acquisition or merger— (1) For the cohort default rates published before the date of the acquisition or merger, your cohort...

  10. 24 CFR 203.666 - Processing defaulted mortgages on property in Allegany Reservation of Seneca Nation of Indians.

    Science.gov (United States)

    2010-04-01

    ... property in Allegany Reservation of Seneca Nation of Indians. 203.666 Section 203.666 Housing and Urban... INSURANCE Servicing Responsibilities Assignment and Forbearance-Property in Allegany Reservation of Seneca Indians § 203.666 Processing defaulted mortgages on property in Allegany Reservation of Seneca Nation...

  11. 25 CFR 103.36 - What options and remedies does the lender have if the borrower defaults on the loan?

    Science.gov (United States)

    2010-04-01

    ... include, for example: (1) Hazard, liability, or key man life insurance premiums; (2) Security measures to... INTERIOR FINANCIAL ACTIVITIES LOAN GUARANTY, INSURANCE, AND INTEREST SUBSIDY Default and Payment by BIA...), will invalidate BIA's loan guaranty certificate or insurance coverage for that particular loan,...

  12. Strategic backdrop analysis for fossil fuel planning. Task 1. Default Case. Report 468-117-07/02

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    This report presents data describing a default case analysis performed using the strategic backdrop analytical framework developed to facilitate fossil fuel planning within the DOE. Target years are 1985, 2000, and 2025. Residential, commercial, and industrial energy demands and impacts of energy technology implementation and market penetration are forecast using a set of energy technology assumptions. (DMC)

  13. Future planning: default network activity couples with frontoparietal control network and reward-processing regions during process and outcome simulations.

    Science.gov (United States)

    Gerlach, Kathy D; Spreng, R Nathan; Madore, Kevin P; Schacter, Daniel L

    2014-12-01

    We spend much of our daily lives imagining how we can reach future goals and what will happen when we attain them. Despite the prevalence of such goal-directed simulations, neuroimaging studies on planning have mainly focused on executive processes in the frontal lobe. This experiment examined the neural basis of process simulations, during which participants imagined themselves going through steps toward attaining a goal, and outcome simulations, during which participants imagined events they associated with achieving a goal. In the scanner, participants engaged in these simulation tasks and an odd/even control task. We hypothesized that process simulations would recruit default and frontoparietal control network regions, and that outcome simulations, which allow us to anticipate the affective consequences of achieving goals, would recruit default and reward-processing regions. Our analysis of brain activity that covaried with process and outcome simulations confirmed these hypotheses. A functional connectivity analysis with posterior cingulate, dorsolateral prefrontal cortex and anterior inferior parietal lobule seeds showed that their activity was correlated during process simulations and associated with a distributed network of default and frontoparietal control network regions. During outcome simulations, medial prefrontal cortex and amygdala seeds covaried together and formed a functional network with default and reward-processing regions.

  14. Studying Cultural Default of Subtitle Translation Based on Relevance Theory:A Case Study of White Collar

    Institute of Scientific and Technical Information of China (English)

    褚杨杨; 李梦

    2015-01-01

    Relevance theory as a new kind of language cognition model theory features of strong practicability and maneuverability. Cultural differences between China and western country wil inevitably contribute to cultural default. Therefore, the introducing of the relevance theory in subtitles translation, can effectively improve the translation accuracy and vitality of the expression.

  15. 40 CFR Table 3 to Subpart Pppp of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends 3 Table 3 to Subpart PPPP of Part 63 Protection of Environment ENVIRONMENTAL... of Plastic Parts and Products Pt. 63, Subpt. PPPP, Table 3 Table 3 to Subpart PPPP of Part...

  16. 40 CFR Table 4 to Subpart Pppp of... - Default Organic HAP Mass Fraction for Petroleum Solvent Groups a

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Default Organic HAP Mass Fraction for Petroleum Solvent Groups a 4 Table 4 to Subpart PPPP of Part 63 Protection of Environment ENVIRONMENTAL... of Plastic Parts and Products Pt. 63, Subpt. PPPP, Table 4 Table 4 to Subpart PPPP of Part...

  17. Strategic backdrop analysis for fossil fuel planning. Task 1. Default Case. Report 468-117-07/01

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    This report presents data describing a default case analysis performed using the strategic backdrop analytical framework developed to facilitate fossil fuel planning within the DOE. Target years are 1985 and 2025. Residential, commercial, and industrial energy demands are forecast as well as the impacts of energy technology implementation and market penetration using a set of energy technology assumptions. (DMC)

  18. Short-term antidepressant administration reduces default mode and task-positive network connectivity in healthy individuals during rest

    NARCIS (Netherlands)

    van Wingen, Guido A; Tendolkar, Indira; Urner, Maren; van Marle, Hein J; Denys, D.; Verkes, Robbert-Jan; Fernández, Guillén

    2014-01-01

    Resting-state studies in depressed patients have revealed increased connectivity within the default mode network (DMN) and task-positive network (TPN). This has been associated with heightened rumination, which is the tendency to repetitively think about symptoms of distress. Here, we performed a ph

  19. Short-term antidepressant administration reduces default mode and task-positive network connectivity in healthy individuals during rest

    NARCIS (Netherlands)

    Wingen, G.A. van; Tendolkar, I.; Urner, M.; Marle, H.J.F. van; Denys, D.; Verkes, R.J.; Fernandez, G.S.E.

    2013-01-01

    Resting-state studies in depressed patients have revealed increased connectivity within the default mode network (DMN) and task-positive network (TPN). This has been associated with heightened rumination, which is the tendency to repetitively think about symptoms of distress. Here, we performed a ph

  20. Of Religion and Redemption : Evidence from Default on Islamic Loans (Replaced by CentER DP 2012-014)

    NARCIS (Netherlands)

    Baele, L.; Farooq, M.; Ongena, S.

    2010-01-01

    We study default rates on conventional and Islamic loans using a comprehensive monthly dataset from Pakistan that follows more than 150,000 loans over the period 2006:04 to 2008:12. We find robust evidence that the hazard rate on Islamic loans is less than half the hazard rate on conventional loans.

  1. Of Religion and Redemption : Evidence from Default on Islamic Loans (Replaced by EBC DP 2012-008)

    NARCIS (Netherlands)

    Baele, L.; Farooq, M.; Ongena, S.

    2010-01-01

    We study default rates on conventional and Islamic loans using a comprehensive monthly dataset from Pakistan that follows more than 150,000 loans over the period 2006:04 to 2008:12. We find robust evidence that the hazard rate on Islamic loans is less than half the hazard rate on conventional loans.

  2. Deriving Default Dermal Exposure Values for Use in a Risk Assessment Toolkit for Small and Medium-sized Enterprises

    NARCIS (Netherlands)

    Warren, N.; Goede, H.A.; Tijssen, S.C.H.A.; Oppl, R.; Schipper, H.J.; Hemmen, J.J. van

    2003-01-01

    This paper describes the derivation of default task-based dermal exposure values for use in a risk assessment toolkit for small and medium-sized enterprises (SMEs). A set of separately determined dermal exposure modifiers have been applied to published studies of dermal exposure to obtain 'normalize

  3. Neural induction from ES cells portrays default commitment but instructive maturation.

    Directory of Open Access Journals (Sweden)

    Nibedita Lenka

    Full Text Available The neural induction has remained a debatable issue pertaining to whether it is a mere default process or it involves precise instructive cues. We have chosen the embryonic stem (ES cell model to address this issue. In a devised monoculture strategy, the cell-cell interaction availed through optimum cell plating density could define the niche for the attainment of efficient in vitro neurogenesis from the ES cells. The medium plating density was found ideal in generating optimum number of progenitors and also yielded about 80% mature neurons in a serum free culture set up barring any exogenous inducers. We could also demarcate and quantify the neural stem cells/progenitors among the heterogeneous cell population of differentiating ES cells using nestin intron II driven EGFP expression as a tool. The one week post-plating was determined to be the critical time window for optimum neural progenitor generation from ES cells that helped us further in purifying these cells and in demonstrating their proliferation and multipotent differentiation potential. Seeding cells at varying densities, we could decipher an interesting paradoxical scenario that interlinked both commitment and maturation with the initial plating density having a vital influence on neuronal maturation but not specification and the secretory factors were apparently playing a key role during this process. Thus it was comprehended that, the neural specification was a default process independent of exogenous factors and cellular interaction. Conversely, a defined number of cells at the specification stage itself seemed critical to provide an auto-/paracrine means of signaling threshold for the maturation process to materialize.

  4. Search-related suppression of hippocampus and default network activity during associative memory retrieval

    Directory of Open Access Journals (Sweden)

    Emilie T Reas

    2011-10-01

    Full Text Available Episodic memory retrieval involves the coordinated interaction of several cognitive processing stages such as mental search, access to a memory store, associative re-encoding and post-retrieval monitoring. The neural response during memory retrieval is an integration of signals from multiple regions that may subserve supportive cognitive control, attention, sensory association, encoding or working memory functions. It is particularly challenging to dissociate contributions of these distinct components to brain responses in regions such as the hippocampus, which lies at the interface between overlapping memory encoding and retrieval, and default networks. In the present study, event-related functional magnetic resonance imaging and measures of memory performance were used to differentiate brain responses to memory search from sub-components of episodic memory retrieval associated with successful recall. During the attempted retrieval of both poorly and strongly remembered word pair associates, the hemodynamic response was negatively deflected below baseline in anterior hippocampus and regions of the default network. Activations in anterior hippocampus were functionally distinct from those in posterior hippocampus and negatively correlated with response times. Thus, relative to the pre-stimulus period, the hippocampus shows reduced activity during intensive engagement in episodic memory search. Such deactivation was most salient during trials that engaged only pre-retrieval search processes in the absence of successful recollection or post-retrieval processing. Implications for interpretation of hippocampal fMRI responses during retrieval are discussed. A model is presented to interpret such activations as representing modulation of encoding-related activity, rather than retrieval-related activity. Engagement in intensive mental search may reduce neural and attentional resources that are otherwise tonically devoted to encoding an individual

  5. The roles of reward, default, and executive control networks in set-shifting impairments in schizophrenia.

    Directory of Open Access Journals (Sweden)

    James A Waltz

    Full Text Available Patients with schizophrenia (SZ show deficits on tasks of rapid reinforcement learning, like probabilistic reversal learning (PRL, but the neural bases for those impairments are not known. Recent evidence of relatively intact sensitivity to negative outcomes in the ventral striatum (VS in many SZ patients suggests that PRL deficits may be largely attributable to processes downstream from feedback processing, involving both the activation of executive control task regions and deactivation of default mode network (DMN components. We analyzed data from 29 chronic SZ patients and 21 matched normal controls (NCs performing a PRL task in an MRI scanner. Subjects were presented with eight pairs of fractal stimuli, for 50 trials each. For each pair, subjects learned to choose the more frequently-rewarded (better stimulus. Each time a criterion was reached, the better stimulus became the worse one, and the worse became the better. Responses to feedback events were assessed through whole-brain and regions-of-interest (ROI analyses in DMN. We also assessed correlations between BOLD signal contrasts and clinical measures in SZs. Relative to NCs, SZ patients showed comparable deactivation of VS in response to negative feedback, but reduced deactivation of DMN components including medial prefrontal cortex (mPFC. The magnitudes of patients' punishment-evoked deactivations in VS and ventromedial PFC correlated significantly with clinical ratings for avolition/anhedonia. These findings suggest that schizophrenia is associated with a reduced ability to deactivate components of default mode networks, following the presentation of informative feedback and that motivational deficits in SZ relate closely to feedback-evoked activity in reward circuit components. These results also confirm a role for ventrolateral and dorsomedial PFC in the execution of response-set shifts.

  6. Abnormal Default-Mode Network Activation in Cirrhotic Patients: A Functional Magnetic Resonance Imaging Study

    International Nuclear Information System (INIS)

    Background: Recently, increasing numbers of studies have demonstrated that, in humans, a default-mode functional network exists in the resting state. Abnormal default-mode network in various diseases has been reported; however, no report concerning hepatic cirrhosis has been published to date. Purpose: To prospectively explore whether the resting-state network in patients with hepatic cirrhosis is abnormal or not, using functional magnetic resonance imaging (fMRI). Material and Methods: 14 patients with hepatic cirrhosis (12 male, two female; 45±9 years) and 14 age- and gender-matched healthy volunteers (12 male, two female; 42±10 years) participated in a blocked-design fMRI study. A modified Stroop task with Chinese characters was used as the target stimulus. Statistical Parametric Mapping 99 software was employed to process the functional data. Individual maps and group data were generated for patients with hepatic cirrhosis and for healthy controls, respectively. Intergroup analysis between patients and healthy controls was also generated using the two-sample t-test model. Cluster analyses were done based on the group data, and an identical P value 0.01 with continuously connected voxels of no less than 10 was defined as significant deactivation. After fMRI scanning was complete, behavioral Stroop interference tests were performed on all subjects; reaction time and error number were recorded. Results: Functionally, deactivation of the posterior cingulate cortex (PCC) and precuneus was absent when subjects performed the incongruous word-reading task; deactivation of the PCC, precuneus, and ventral medial prefrontal cortex was increased when they performed the incongruous color-naming task. Conclusion: The functional as well as behavioral data suggest that cirrhotic patients may have an abnormal deactivation mode. The absence of deactivation in the PCC and precuneus may be a sensitive rather than specific marker in patients with hepatic cirrhosis

  7. The roles of reward, default, and executive control networks in set-shifting impairments in schizophrenia.

    Science.gov (United States)

    Waltz, James A; Kasanova, Zuzana; Ross, Thomas J; Salmeron, Betty J; McMahon, Robert P; Gold, James M; Stein, Elliot A

    2013-01-01

    Patients with schizophrenia (SZ) show deficits on tasks of rapid reinforcement learning, like probabilistic reversal learning (PRL), but the neural bases for those impairments are not known. Recent evidence of relatively intact sensitivity to negative outcomes in the ventral striatum (VS) in many SZ patients suggests that PRL deficits may be largely attributable to processes downstream from feedback processing, involving both the activation of executive control task regions and deactivation of default mode network (DMN) components. We analyzed data from 29 chronic SZ patients and 21 matched normal controls (NCs) performing a PRL task in an MRI scanner. Subjects were presented with eight pairs of fractal stimuli, for 50 trials each. For each pair, subjects learned to choose the more frequently-rewarded (better) stimulus. Each time a criterion was reached, the better stimulus became the worse one, and the worse became the better. Responses to feedback events were assessed through whole-brain and regions-of-interest (ROI) analyses in DMN. We also assessed correlations between BOLD signal contrasts and clinical measures in SZs. Relative to NCs, SZ patients showed comparable deactivation of VS in response to negative feedback, but reduced deactivation of DMN components including medial prefrontal cortex (mPFC). The magnitudes of patients' punishment-evoked deactivations in VS and ventromedial PFC correlated significantly with clinical ratings for avolition/anhedonia. These findings suggest that schizophrenia is associated with a reduced ability to deactivate components of default mode networks, following the presentation of informative feedback and that motivational deficits in SZ relate closely to feedback-evoked activity in reward circuit components. These results also confirm a role for ventrolateral and dorsomedial PFC in the execution of response-set shifts. PMID:23468948

  8. Short-course treatment for multidrug-resistant tuberculosis: the STREAM trials.

    Science.gov (United States)

    Moodley, Riya; Godec, Thomas R

    2016-03-01

    Multidrug-resistant (MDR) tuberculosis (TB) is a threat to global TB control, as suboptimal and poorly tolerated treatment options have resulted in largely unfavourable outcomes for these patients. The last of six cohort studies conducted in Bangladesh which assessed a new shorter regimen using currently available TB drugs showed promising results and offered the possibility of a more acceptable and more effective regimen than the one recommended by the World Health Organization (WHO). The aims of stage 1 of the STREAM (Evaluation of a Standardised Treatment Regimen of Anti-tuberculosis Drugs for Patients with Multidrug-resistant Tuberculosis) trial are to evaluate the efficacy and safety of this regimen, compared to the current WHO-recommended standard of care. Stage 2 evaluates two new bedaquiline-containing regimens: one an all-oral regimen and the second a further shortened and simplified version of the stage 1 study regimen, comparing the efficacy and safety of each to that of the stage 1 study regimen and also to the WHO-recommended standard of care. Success of the stage 1 study regimen would in all probability provide a new standard of care for MDR-TB patients, while positive results from the bedaquiline-containing regimens in stage 2 may allow for even greater progress in the management of this difficult population. PMID:26929418

  9. Short-course treatment for multidrug-resistant tuberculosis: the STREAM trials

    Directory of Open Access Journals (Sweden)

    Riya Moodley

    2016-03-01

    Full Text Available Multidrug-resistant (MDR tuberculosis (TB is a threat to global TB control, as suboptimal and poorly tolerated treatment options have resulted in largely unfavourable outcomes for these patients. The last of six cohort studies conducted in Bangladesh which assessed a new shorter regimen using currently available TB drugs showed promising results and offered the possibility of a more acceptable and more effective regimen than the one recommended by the World Health Organization (WHO. The aims of stage 1 of the STREAM (Evaluation of a Standardised Treatment Regimen of Anti-tuberculosis Drugs for Patients with Multidrug-resistant Tuberculosis trial are to evaluate the efficacy and safety of this regimen, compared to the current WHO-recommended standard of care. Stage 2 evaluates two new bedaquiline-containing regimens: one an all-oral regimen and the second a further shortened and simplified version of the stage 1 study regimen, comparing the efficacy and safety of each to that of the stage 1 study regimen and also to the WHO-recommended standard of care. Success of the stage 1 study regimen would in all probability provide a new standard of care for MDR-TB patients, while positive results from the bedaquiline-containing regimens in stage 2 may allow for even greater progress in the management of this difficult population.

  10. The procurement landscape of pediatric tuberculosis treatment: a Global Drug Facility perspective.

    Science.gov (United States)

    Scott, C; Gardiner, E; de Lucia, A

    2015-12-01

    Simple, quality-assured, child-friendly formulations of existing first-line anti-tuberculosis (TB) drugs in the correct dosages are now becoming available. Efforts are currently underway by the TB Alliance, the World Health Organization (WHO), and its partners to make appropriate medicines available to treat children diagnosed with TB. The functioning of the current market and the distribution pathways in pediatric TB drugs now require characterization and understanding in order to develop appropriate strategies for delivery of these and other future pediatric TB medicines. The Stop TB Partnership's Global Drug Facility (GDF) plays a major role in supplying pediatric TB medications worldwide. GDF is considered to be the largest procurer of pediatric TB treatment and the largest supplier to national TB programs of quality pediatric drugs. Between 2007 and 2013, the GDF delivered more than 580, 000 treatments to children in over 50 countries, 14 of which are among the 22 high TB burden countries. We analyzed this data set in the context of WHO estimates of pediatric TB as well as other available information to assess the functioning of the current market, lessons learnt from the GDF experience in the market, and opportunities for future products. PMID:26564536

  11. Systemic BCG-Osis as a Rare Side Effect of Intravesical BCG Treatment for Superficial Bladder Cancer

    Directory of Open Access Journals (Sweden)

    S. Lukacs

    2013-01-01

    Full Text Available Intravesical Bacilli Calmette-Guérin (BCG immunotherapy is a commonly used treatment for superficial bladder cancer. Although the treatment is well tolerated in 95% of cases, life-threatening side effects including BCG sepsis can occur. This report describes the case of an 82-year-old man with a background of lung disease. He developed septic shock and type two respiratory failure after receiving the sixth installation of intravesical BCG (TICE strain immunotherapy for recurrent bladder Transitional Cell Carcinoma in situ. Despite the early initiation of broad spectrum antibiotics (tazocin and gentamicin, he remained pyrexial. There was a rapid deterioration, and on the second day of his admission, he developed type two respiratory failure secondary to Acute Respiratory Distress Syndrome (ARDS prompting transfer to Intensive Care for Bilevel Positive Airway Pressure (BiPAP Ventilation. The blood cultures taken before the induction of antibiotics results were negative. Increasing clinical suspicion of systemic BCG-osis prompted the initiation of antituberculosis therapy (ethambutol, isoniazid rifampicin and steroids. Following six days of BiPAP and anti-tuberculosis therapy in ITU, his condition started to improve. Following a prolonged hospital stay he was discharged on long term ethambutol therapy. BCG-osis is a well-known though rare side effect of intravesical BCG therapy. We would like to highlight the importance of having a low threshold for starting anti-TB treatment.

  12. Systemic BCG-Osis as a Rare Side Effect of Intravesical BCG Treatment for Superficial Bladder Cancer.

    Science.gov (United States)

    Lukacs, S; Tschobotko, B; Szabo, N A; Symes, Andrew

    2013-01-01

    Intravesical Bacilli Calmette-Guérin (BCG) immunotherapy is a commonly used treatment for superficial bladder cancer. Although the treatment is well tolerated in 95% of cases, life-threatening side effects including BCG sepsis can occur. This report describes the case of an 82-year-old man with a background of lung disease. He developed septic shock and type two respiratory failure after receiving the sixth installation of intravesical BCG (TICE strain) immunotherapy for recurrent bladder Transitional Cell Carcinoma in situ. Despite the early initiation of broad spectrum antibiotics (tazocin and gentamicin), he remained pyrexial. There was a rapid deterioration, and on the second day of his admission, he developed type two respiratory failure secondary to Acute Respiratory Distress Syndrome (ARDS) prompting transfer to Intensive Care for Bilevel Positive Airway Pressure (BiPAP) Ventilation. The blood cultures taken before the induction of antibiotics results were negative. Increasing clinical suspicion of systemic BCG-osis prompted the initiation of antituberculosis therapy (ethambutol, isoniazid rifampicin) and steroids. Following six days of BiPAP and anti-tuberculosis therapy in ITU, his condition started to improve. Following a prolonged hospital stay he was discharged on long term ethambutol therapy. BCG-osis is a well-known though rare side effect of intravesical BCG therapy. We would like to highlight the importance of having a low threshold for starting anti-TB treatment. PMID:23844314

  13. Functional connectivity of paired default mode network subregions in primary insomnia

    Directory of Open Access Journals (Sweden)

    Nie X

    2015-12-01

    Full Text Available Xiao Nie,1,* Yi Shao,2,* Si-yu Liu,3 Hai-jun Li,1 Ai-lan Wan,4 Si Nie,1 De-chang Peng,1 Xi-jian Dai1,5 1Department of Radiology, The First Affiliated Hospital of Nanchang University, Nangchang, Jiangxi, People’s Republic of China; 2Department of Ophthalmology,The First Affiliated Hospital of Nanchang University, Nangchang, Jiangxi, People’s Republic of China; 3Medical College of Nanchang University, Nangchang, Jiangxi, People’s Republic of China; 4Department of Psychosomatic Medicine, The First Affiliated Hospital of Nanchang University, Nangchang, Jiangxi, People’s Republic of China; 5Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People’s Republic of China *These authors contributed equally to this work Objective: The aim of this study is to explore the resting-state functional connectivity (FC differences between the paired default mode network (DMN subregions in patients with primary insomnia (PIs.Methods: Forty-two PIs and forty-two age- and sex-matched good sleepers (GSs were recruited. All subjects underwent the resting-state functional magnetic resonance imaging scans. The seed-based region-to-region FC method was used to evaluate the abnormal connectivity within the DMN subregions between the PIs and the GSs. Pearson correlation analysis was used to investigate the relationships between the abnormal FC strength within the paired DMN subregions and the clinical features in PIs.Results: Compared with the GSs, the PIs showed higher Pittsburgh Sleep Quality Index score, Hamilton Anxiety Rating Scale score, Hamilton Depression Rating Scale score, Self-Rating Depression Scale score, Self Rating Anxiety Scale score, Self-Rating Scale of Sleep score, and Profile of Mood States score (P<0.001. Compared with the GSs, the PIs showed significant decreased region-to-region FC between the medial prefrontal cortex and the right medial temporal lobe (t=-2.275, P

  14. Mortality and failure among tuberculosis patients who did not complete treatment in Vietnam: a cohort study

    Directory of Open Access Journals (Sweden)

    Van Le N

    2007-07-01

    Full Text Available Abstract Background Tuberculosis treatment failure and death rates are low in the Western Pacific Region, including Vietnam. However, failure or death may also occur among patients who did not complete treatment, i.e. reported as default or transfer-out. We aimed to assess the proportion failures and deaths among new smear-positive pulmonary tuberculosis patients with reported default or transfer-out. Treatment outcomes rates were 1.4% default, 3.0% transfer-out, 0.4% failure and 2.6% death in northern Vietnam in 2003. Methods Tuberculosis patients in 32 randomly selected district tuberculosis units in northern Vietnam were followed up 1 to 3 years after treatment initiation for survival, recent treatment history and bacteriologically confirmed tuberculosis. Results Included were 85 transferred patients and 42 who defaulted. No information was available of 41 (32%, 28 (22% had died. Fifty-eight were available for follow-up (46%; all had sputum smear results. Tuberculosis was recorded in 11 (13%, including 6 (7% with positive sputum smears, 3 (3% with negative smears but positive culture and 2 (2% who had started re-treatment for bacteriologically confirmed tuberculosis. Fifteen (17%, 95%CI 10–27% had died within 8 months after treatment initiation. Of 86 patients with known study outcomes, 39 (45%, 95%CI 35–56% had died or had bacteriologically confirmed tuberculosis. This was recorded for 29/53 (55%, 95%CI 40–68% transferred patients and 10/33 (30%, 95%CI 16–49% patients who defaulted. Conclusion The total failure and death rates are 0.6% and 0.8% higher than based on routine reporting in northern Vietnam. Although this was a large proportion of treatment failures and deaths, failure and death rates were low. Defaulting and transfer carry a high risk of failure and in particular death.

  15. Determination of the default curve for the unfolding procedure in the measurement of threshold neutron excitation functions

    Energy Technology Data Exchange (ETDEWEB)

    Jovancevic, Nikola; Daraban, Laura; Oberstedt, Stephan, E-mail: stephan.oberstedt@ec.europa.eu

    2014-03-01

    In this study we have improved the technique for measuring the neutron activation cross-section using wide energy neutron beams (NAXSUN). We propose a method for the determination of the default function for the unfolding procedure, which is an important and critical part for extracting reaction cross-sections from this type of measurements. The new method was tested on the measurement of the excitation function from the threshold energy up to 5.6 MeV for the {sup 113}In(n,n'){sup 113m}In and {sup 115}In(n,n'){sup 115m}In reactions. - Highlights: • Determination of default curve for unfolding procedure solely based on actual measurement. • No input from data libraries or model calculations necessary.

  16. The default response to uncertainty and the importance of perceived safety in anxiety and stress: An evolution-theoretical perspective.

    Science.gov (United States)

    Brosschot, Jos F; Verkuil, Bart; Thayer, Julian F

    2016-06-01

    From a combined neurobiological and evolution-theoretical perspective, the stress response is a subcortically subserved response to uncertainty that is not 'generated' but 'default': the stress response is 'always there' but as long as safety is perceived, the stress response is under tonic prefrontal inhibition, reflected by high vagally mediated heart rate variability. Uncertainty of safety leads to disinhibiting the default stress response, even in the absence of threat. Due to the stress response's survival value, this 'erring on the side of caution' is passed to us via our genes. Thus, intolerance of uncertainty is not acquired during the life cycle, but is a given property of all living organisms, only to be alleviated in situations of which the safety is learned. When the latter is deficient, generalized unsafety ensues, which underlies chronic anxiety and stress and their somatic health risks, as well as other highly prevalent conditions carrying such risks, including loneliness, obesity, aerobic unfitness and old age. PMID:27259803

  17. Altered functional connectivity of the default mode network in Williams syndrome: a multimodal approach.

    Science.gov (United States)

    Sampaio, Adriana; Moreira, Pedro Silva; Osório, Ana; Magalhães, Ricardo; Vasconcelos, Cristiana; Férnandez, Montse; Carracedo, Angel; Alegria, Joana; Gonçalves, Óscar F; Soares, José Miguel

    2016-07-01

    Resting state brain networks are implicated in a variety of relevant brain functions. Importantly, abnormal patterns of functional connectivity (FC) have been reported in several neurodevelopmental disorders. In particular, the Default Mode Network (DMN) has been found to be associated with social cognition. We hypothesize that the DMN may be altered in Williams syndrome (WS), a neurodevelopmental genetic disorder characterized by an unique cognitive and behavioral phenotype. In this study, we assessed the architecture of the DMN using fMRI in WS patients and typically developing matched controls (sex and age) in terms of FC and volumetry of the DMN. Moreover, we complemented the analysis with a functional connectome approach. After excluding participants due to movement artifacts (n = 3), seven participants with WS and their respective matched controls were included in the analyses. A decreased FC between the DMN regions was observed in the WS group when compared with the typically developing group. Specifically, we found a decreased FC in a posterior hub of the DMN including the precuneus, calcarine and the posterior cingulate of the left hemisphere. The functional connectome approach showed a focalized and global increased FC connectome in the WS group. The reduced FC of the posterior hub of the DMN in the WS group is consistent with immaturity of the brain FC patterns and may be associated with the singularity of their visual spatial phenotype. PMID:27412230

  18. Hemispheric asymmetries of functional connectivity and grey matter volume in the default mode network.

    Science.gov (United States)

    Saenger, Victor M; Barrios, Fernando A; Martínez-Gudiño, María L; Alcauter, Sarael

    2012-06-01

    Resting state networks such as the default mode network have been widely reported. Although a plethora of information on its functional relevance has been generated, little is known about lateralization or hemisphere asymmetry within the DMN. We used high-resolution resting state fMRI and T1 3D data to investigate such asymmetries in two groups of healthy subjects, one right-handed and one left-handed. Independent component analysis and the dual regression approach were carried out to identify functional asymmetries, while voxel-based morphometry was used to identify structural asymmetries in grey matter volume within the DMN. Greater leftward functional connectivity was observed in the posterior cingulate gyrus (PCG) for both groups. Leftward functional asymmetry was observed in the thalamus and rightward functional asymmetries were observed in the middle frontal and middle/superior temporal gyrus in the right-handed group. Rightward asymmetries in grey matter volume were observed in the posterior portion of the PCG for both groups. The right-handed group exhibited leftward structural asymmetries in the anterior portion of the PCG and in the middle frontal and posterior portion of the middle temporal gyrus, while rightward asymmetries were observed in the posterior portion of the PCG and anterior portions of temporal regions. These results suggest that functional connectivity and grey matter volume are not equally distributed between hemispheres within the DMN, and that functional asymmetries are not always reflected or determined by structural asymmetries.

  19. Impaired functional default mode network in patients with mild neurological Wilson's disease.

    Science.gov (United States)

    Han, Yongsheng; Cheng, Hewei; Toledo, Jon B; Wang, Xun; Li, Bo; Han, Yongzhu; Wang, Kai; Fan, Yong

    2016-09-01

    Wilson's disease (WD) is an autosomal recessive metabolic disorder characterized by cognitive, psychiatric and motor signs and symptoms that are associated with structural and pathological brain abnormalities, in addition to liver changes. However, functional brain connectivity pattern of WD patients remains largely unknown. In the present study, we investigated functional brain connectivity pattern of WD patients using resting state functional magnetic resonance imaging. Particularly, we studied default mode network (DMN) using posterior cingulate cortex (PCC) based seed functional connectivity analysis and graph theoretic functional brain network analysis tools, and investigated the relationship between the DMN's functional connectivity pattern of WD patients and their attention functions examined using the attention network test (ANT). Our results demonstrated that WD patients had altered DMN's functional connectivity and lower local and global network efficiency compared with normal controls (NCs). In addition, the functional connectivity between left inferior temporal cortex and right lateral parietal cortex was correlated with altering function, one of the attention functions, across WD and NC subjects. These findings indicated that the DMN's functional connectivity was altered in WD patients, which might be correlated with their attention dysfunction.

  20. Personality and complex brain networks: The role of openness to experience in default network efficiency.

    Science.gov (United States)

    Beaty, Roger E; Kaufman, Scott Barry; Benedek, Mathias; Jung, Rex E; Kenett, Yoed N; Jauk, Emanuel; Neubauer, Aljoscha C; Silvia, Paul J

    2016-02-01

    The brain's default network (DN) has been a topic of considerable empirical interest. In fMRI research, DN activity is associated with spontaneous and self-generated cognition, such as mind-wandering, episodic memory retrieval, future thinking, mental simulation, theory of mind reasoning, and creative cognition. Despite large literatures on developmental and disease-related influences on the DN, surprisingly little is known about the factors that impact normal variation in DN functioning. Using structural equation modeling and graph theoretical analysis of resting-state fMRI data, we provide evidence that Openness to Experience-a normally distributed personality trait reflecting a tendency to engage in imaginative, creative, and abstract cognitive processes-underlies efficiency of information processing within the DN. Across two studies, Openness predicted the global efficiency of a functional network comprised of DN nodes and corresponding edges. In Study 2, Openness remained a robust predictor-even after controlling for intelligence, age, gender, and other personality variables-explaining 18% of the variance in DN functioning. These findings point to a biological basis of Openness to Experience, and suggest that normally distributed personality traits affect the intrinsic architecture of large-scale brain systems. Hum Brain Mapp 37:773-779, 2016. © 2015 Wiley Periodicals, Inc.

  1. Data for default network reduced functional connectivity in meditators, negatively correlated with meditation expertise

    Directory of Open Access Journals (Sweden)

    Aviva Berkovich-Ohana

    2016-09-01

    Full Text Available FMRI data described here was recorded during resting-state in Mindfulness Meditators (MM and control participants (see “Task-induced activity and resting-state fluctuations undergo similar alterations in visual and DMN areas of long-term meditators” Berkovich-Ohana et al. (2016 [1] for details. MM participants were also scanned during meditation. Analyses focused on functional connectivity within and between the default mode network (DMN and visual network (Vis. Here we show data demonstrating that: 1 Functional connectivity within the DMN and the Visual networks were higher in the control group than in the meditators; 2 Data show an increase for the functional connectivity between the DMN and the Visual networks in the meditators compared to controls; 3 Data demonstrate that functional connectivity both within and between networks reduces during meditation, compared to the resting-state; and 4 A significant negative correlation was found between DMN functional connectivity and meditation expertise. The reader is referred to Berkovich-Ohana et al. (2016 [1] for further interpretation and discussion.

  2. Copula方法与相依违约研究%Copula Approach and Dependent Default Research

    Institute of Scientific and Technical Information of China (English)

    李健伦; 方兆本; 鲁炜; 李红星

    2005-01-01

    目前信用风险研究的重点已经从单笔债务的违约概率研究转移到多笔债务的相依违约(Dependent Defaults)研究.Copula方法是研究相依违约的重要方法.这种方法是最近几年才被应用到信用领域研究中的一种新方法.本文结合代表性文献对Copula方法在相依违约研究中的应用进行了探讨.探讨的内容包括Copula方法被应用于相依违约研究的原因、该方法对于相依违约建模理论的改进以及在实证应用中使用Copula方法应该注意的问题.

  3. Self-processing and the default mode network: Interactions with the mirror neuron system

    Directory of Open Access Journals (Sweden)

    Istvan eMolnar-Szakacs

    2013-09-01

    Full Text Available Recent evidence for the fractionation of the default mode network (DMN into functionally distinguishable subdivisions with unique patterns of connectivity calls for a reconceptualization of the relationship between this network and self-referential processing. Advances in resting-state functional connectivity analyses are beginning to reveal increasingly complex patterns of organization within the key nodes of the DMN - medial prefrontal cortex (MPFC and posterior cingulate cortex (PCC – as well as between these nodes and other brain systems. Here we review recent examinations of the relationships between the DMN and various aspects of self-relevant and social-cognitive processing in light of emerging evidence for heterogeneity within this network. Drawing from a rapidly evolving social cognitive neuroscience literature, we propose that embodied simulation and mentalizing are processes which allow us to gain insight into another's physical and mental state by providing privileged access to our own physical and mental states. Embodiment implies that the same neural systems are engaged for self- and other-understanding through a simulation mechanism, while mentalizing refers to the use of high-level conceptual information to make inferences about the mental states of self and others. These mechanisms work together to provide a coherent representation of the self and by extension, of others. Nodes of the DMN selectively interact with brain systems for embodiment and mentalizing, including the mirror neuron system, to produce appropriate mappings in the service of social cognitive demands.

  4. Precuneus is a functional core of the default-mode network.

    Science.gov (United States)

    Utevsky, Amanda V; Smith, David V; Huettel, Scott A

    2014-01-15

    Efforts to understand the functional architecture of the brain have consistently identified multiple overlapping large-scale neural networks that are observable across multiple states. Despite the ubiquity of these networks, it remains unclear how regions within these large-scale neural networks interact to orchestrate behavior. Here, we collected functional magnetic resonance imaging data from 188 human subjects who engaged in three cognitive tasks and a resting-state scan. Using multiple tasks and a large sample allowed us to use split-sample validations to test for replication of results. We parceled the task-rest pairs into functional networks using a probabilistic spatial independent components analysis. We examined changes in connectivity between task and rest states using dual-regression analysis, which quantifies voxelwise connectivity estimates for each network of interest while controlling for the influence of signals arising from other networks and artifacts. Our analyses revealed systematic state-dependent functional connectivity in one brain region: the precuneus. Specifically, task performance led to increased connectivity (compared with rest) between the precuneus and the right frontoparietal network, whereas rest increased connectivity between the precuneus and the default-mode network (DMN). The absolute magnitude of this effect was greater for DMN, suggesting a heightened specialization for resting-state cognition. All results replicated within the two independent samples. Our results indicate that the precuneus plays a core role not only in DMN, but also more broadly through its engagement under a variety of processing states. PMID:24431451

  5. Accessible cultural mind-set modulates default mode activity: evidence for the culturally situated brain.

    Science.gov (United States)

    Wang, Chenbo; Oyserman, Daphna; Liu, Qiang; Li, Hong; Han, Shihui

    2013-01-01

    Self-construal priming modulates human behavior and associated neural activity. However, the neural activity associated with the self-construal priming procedure itself remains unknown. It is also unclear whether and how self-construal priming affects neural activity prior to engaging in a particular task. To address this gap, we scanned Chinese adults, using functional magnetic resonance imaging, during self-construal priming and a following resting state. We found that, relative to a calculation task, both interdependent and independent self-construal priming activated the ventral medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC). The contrast of interdependent vs. independent self-construal priming also revealed increased activity in the dorsal MPFC and left middle frontal cortex. The regional homogeneity analysis of the resting-state activity revealed increased local synchronization of spontaneous activity in the dorsal MPFC but decreased local synchronization of spontaneous activity in the PCC when contrasting interdependent vs. independent self-construal priming. The functional connectivity analysis of the resting-state activity, however, did not show significant difference in synchronization of activities in remote brain regions between different priming conditions. Our findings suggest that accessible collectivistic/individualistic mind-set induced by self-construal priming is associated with modulations of both task-related and resting-state activity in the default mode network.

  6. What we talk about when we talk about the default mode network

    Directory of Open Access Journals (Sweden)

    Felicity eCallard

    2014-08-01

    Full Text Available The default mode network (DMN has been widely defined as a set of brain regions that are engaged when people are in a ‘resting state’ (left to themselves in a scanner, with no explicit task instruction. The network emerged as a scientific object in the early twenty-first century, and in just over a decade has become the focus of intense empirical and conceptual neuroscientific inquiry. In this Perspective, we contribute to the work of critical neuroscience by providing brief reflections on the birth, working life, and future of the DMN. We consider: how the DMN emerged through the convergence of distinct lines of scientific investigation; controversies surrounding the definition, function and localization of the DMN; and the lines of interdisciplinary investigation that the DMN has helped to enable. We conclude by arguing that one of the most pressing issues in the field in 2014 is to understand how the mechanisms of thought are related to the function of brain dynamics. While the DMN has been central in allowing the field to reach this point, it is not inevitable that the DMN itself will remain at the heart of future investigations of this complex problem.

  7. Spontaneous default mode network phase-locking moderates performance perceptions under stereotype threat.

    Science.gov (United States)

    Forbes, Chad E; Leitner, Jordan B; Duran-Jordan, Kelly; Magerman, Adam B; Schmader, Toni; Allen, John J B

    2015-07-01

    This study assessed whether individual differences in self-oriented neural processing were associated with performance perceptions of minority students under stereotype threat. Resting electroencephalographic activity recorded in white and minority participants was used to predict later estimates of task errors and self-doubt on a presumed measure of intelligence. We assessed spontaneous phase-locking between dipole sources in left lateral parietal cortex (LPC), precuneus/posterior cingulate cortex (P/PCC), and medial prefrontal cortex (MPFC); three regions of the default mode network (DMN) that are integral for self-oriented processing. Results revealed that minorities with greater LPC-P/PCC phase-locking in the theta band reported more accurate error estimations. All individuals experienced less self-doubt to the extent they exhibited greater LPC-MPFC phase-locking in the alpha band but this effect was driven by minorities. Minorities also reported more self-doubt to the extent they overestimated errors. Findings reveal novel neural moderators of stereotype threat effects on subjective experience. Spontaneous synchronization between DMN regions may play a role in anticipatory coping mechanisms that buffer individuals from stereotype threat.

  8. Task-induced deactivation from rest extends beyond the default mode brain network.

    Directory of Open Access Journals (Sweden)

    Ben J Harrison

    Full Text Available Activity decreases, or deactivations, of midline and parietal cortical brain regions are routinely observed in human functional neuroimaging studies that compare periods of task-based cognitive performance with passive states, such as rest. It is now widely held that such task-induced deactivations index a highly organized 'default-mode network' (DMN: a large-scale brain system whose discovery has had broad implications in the study of human brain function and behavior. In this work, we show that common task-induced deactivations from rest also occur outside of the DMN as a function of increased task demand. Fifty healthy adult subjects performed two distinct functional magnetic resonance imaging tasks that were designed to reliably map deactivations from a resting baseline. As primary findings, increases in task demand consistently modulated the regional anatomy of DMN deactivation. At high levels of task demand, robust deactivation was observed in non-DMN regions, most notably, the posterior insular cortex. Deactivation of this region was directly implicated in a performance-based analysis of experienced task difficulty. Together, these findings suggest that task-induced deactivations from rest are not limited to the DMN and extend to brain regions typically associated with integrative sensory and interoceptive processes.

  9. Functional Connectivity with the Default Mode Network Is Altered in Fibromyalgia Patients.

    Science.gov (United States)

    Fallon, Nicholas; Chiu, Yee; Nurmikko, Turo; Stancak, Andrej

    2016-01-01

    Fibromyalgia syndrome (FMS) patients show altered connectivity with the network maintaining ongoing resting brain activity, known as the default mode network (DMN). The connectivity patterns of DMN with the rest of the brain in FMS patients are poorly understood. This study employed seed-based functional connectivity analysis to investigate resting-state functional connectivity with DMN structures in FMS. Sixteen female FMS patients and 15 age-matched, healthy control subjects underwent T2-weighted resting-state MRI scanning and functional connectivity analyses using DMN network seed regions. FMS patients demonstrated alterations to connectivity between DMN structures and anterior midcingulate cortex, right parahippocampal gyrus, left superior parietal lobule and left inferior temporal gyrus. Correlation analysis showed that reduced functional connectivity between the DMN and the right parahippocampal gyrus was associated with longer duration of symptoms in FMS patients, whereas augmented connectivity between the anterior midcingulate and posterior cingulate cortices was associated with tenderness and depression scores. Our findings demonstrate alterations to functional connectivity between DMN regions and a variety of regions which are important for pain, cognitive and emotional processing in FMS patients, and which may contribute to the development or maintenance of chronic symptoms in FMS. PMID:27442504

  10. Metabolic mapping reveals sex-dependent involvement of default mode and salience network in alexithymia.

    Science.gov (United States)

    Colic, L; Demenescu, L R; Li, M; Kaufmann, J; Krause, A L; Metzger, C; Walter, M

    2016-02-01

    Alexithymia, a personality construct marked by difficulties in processing one's emotions, has been linked to the altered activity in the anterior cingulate cortex (ACC). Although longitudinal studies reported sex differences in alexithymia, what mediates them is not known. To investigate sex-specific associations of alexithymia and neuronal markers, we mapped metabolites in four brain regions involved differentially in emotion processing using a point-resolved spectroscopy MRS sequence in 3 Tesla. Both sexes showed negative correlations between alexithymia and N-acetylaspartate (NAA) in pregenual ACC (pgACC). Women showed a robust negative correlation of the joint measure of glutamate and glutamine (Glx) to NAA in posterior cingulate cortex (PCC), whereas men showed a weak positive association of Glx to NAA in dorsal ACC (dACC). Our results suggest that lowered neuronal integrity in pgACC, a region of the default mode network (DMN), might primarily account for the general difficulties in emotional processing in alexithymia. Association of alexithymia in women extends to another region in the DMN-PCC, while in men a region in the salience network (SN) was involved. These observations could be representative of sex specific regulation strategies that include diminished internal evaluation of feelings in women and cognitive emotion suppression in men. PMID:26341904

  11. Data for default network reduced functional connectivity in meditators, negatively correlated with meditation expertise.

    Science.gov (United States)

    Berkovich-Ohana, Aviva; Harel, Michal; Hahamy, Avital; Arieli, Amos; Malach, Rafael

    2016-09-01

    FMRI data described here was recorded during resting-state in Mindfulness Meditators (MM) and control participants (see "Task-induced activity and resting-state fluctuations undergo similar alterations in visual and DMN areas of long-term meditators" Berkovich-Ohana et al. (2016) [1] for details). MM participants were also scanned during meditation. Analyses focused on functional connectivity within and between the default mode network (DMN) and visual network (Vis). Here we show data demonstrating that: 1) Functional connectivity within the DMN and the Visual networks were higher in the control group than in the meditators; 2) Data show an increase for the functional connectivity between the DMN and the Visual networks in the meditators compared to controls; 3) Data demonstrate that functional connectivity both within and between networks reduces during meditation, compared to the resting-state; and 4) A significant negative correlation was found between DMN functional connectivity and meditation expertise. The reader is referred to Berkovich-Ohana et al. (2016) [1] for further interpretation and discussion. PMID:27508242

  12. Abnormal brain default-mode network functional connectivity in drug addicts.

    Directory of Open Access Journals (Sweden)

    Ning Ma

    Full Text Available BACKGROUND: The default mode network (DMN is a set of brain regions that exhibit synchronized low frequency oscillations at resting-state, and is believed to be relevant to attention and self-monitoring. As the anterior cingulate cortex and hippocampus are impaired in drug addiction and meanwhile are parts of the DMN, the present study examined addiction-related alteration of functional connectivity of the DMN. METHODOLOGY: Resting-state functional magnetic resonance imaging data of chronic heroin users (14 males, age: 30.1±5.3 years, range from 22 to 39 years and non-addicted controls (13 males, age: 29.8±7.2 years, range from 20 to 39 years were investigated with independent component analysis to address their functional connectivity of the DMN. PRINCIPAL FINDINGS: Compared with controls, heroin users showed increased functional connectivity in right hippocampus and decreased functional connectivity in right dorsal anterior cingulate cortex and left caudate in the DMN. CONCLUSIONS: These findings suggest drug addicts' abnormal functional organization of the DMN, and are discussed as addiction-related abnormally increased memory processing but diminished cognitive control related to attention and self-monitoring, which may underlie the hypersensitivity toward drug related cues but weakened strength of cognitive control in the state of addiction.

  13. The Default Mode Network Differentiates Biological From Non-Biological Motion.

    Science.gov (United States)

    Dayan, Eran; Sella, Irit; Mukovskiy, Albert; Douek, Yehonatan; Giese, Martin A; Malach, Rafael; Flash, Tamar

    2016-01-01

    The default mode network (DMN) has been implicated in an array of social-cognitive functions, including self-referential processing, theory of mind, and mentalizing. Yet, the properties of the external stimuli that elicit DMN activity in relation to these domains remain unknown. Previous studies suggested that motion kinematics is utilized by the brain for social-cognitive processing. Here, we used functional MRI to examine whether the DMN is sensitive to parametric manipulations of observed motion kinematics. Preferential responses within core DMN structures differentiating non-biological from biological kinematics were observed for the motion of a realistically looking, human-like avatar, but not for an abstract object devoid of human form. Differences in connectivity patterns during the observation of biological versus non-biological kinematics were additionally observed. Finally, the results additionally suggest that the DMN is coupled more strongly with key nodes in the action observation network, namely the STS and the SMA, when the observed motion depicts human rather than abstract form. These findings are the first to implicate the DMN in the perception of biological motion. They may reflect the type of information used by the DMN in social-cognitive processing. PMID:25217472

  14. The Brain on Art: Intense Aesthetic Experience Activates the Default Mode Network

    Directory of Open Access Journals (Sweden)

    Edward A Vessel

    2012-04-01

    Full Text Available Aesthetic responses to visual art comprise multiple types of experiences, from sensation and perception to emotion and self-reflection. Moreover, aesthetic experience is highly individual, with observers varying significantly in their responses to the same artwork. Combining fMRI and behavioral analysis of individual differences in aesthetic response, we identify two distinct patterns of neural activity exhibited by different subnetworks. Activity increased linearly with observers’ ratings (4-level scale in sensory (occipito-temporal regions. Activity in the striatum also varied linearly with ratings, with below-baseline activations for low-rated artworks. In contrast, a network of frontal regions showed a step-like increase only for the most moving artworks (4 ratings and non-differential activity for all others. This included several regions belonging to the default mode network previously associated with self-referential mentation. Our results suggest that aesthetic experience involves the integration of sensory and emotional reactions in a manner linked with their personal relevance.

  15. Cortical morphometry in frontoparietal and default mode networks in math-gifted adolescents.

    Science.gov (United States)

    Navas-Sánchez, Francisco J; Carmona, Susana; Alemán-Gómez, Yasser; Sánchez-González, Javier; Guzmán-de-Villoria, Juan; Franco, Carolina; Robles, Olalla; Arango, Celso; Desco, Manuel

    2016-05-01

    Math-gifted subjects are characterized by above-age performance in intelligence tests, exceptional creativity, and high task commitment. Neuroimaging studies reveal enhanced functional brain organization and white matter microstructure in the frontoparietal executive network of math-gifted individuals. However, the cortical morphometry of these subjects remains largely unknown. The main goal of this study was to compare the cortical morphometry of math-gifted adolescents with that of an age- and IQ-matched control group. We used surface-based methods to perform a vertex-wise analysis of cortical thickness and surface area. Our results show that math-gifted adolescents present a thinner cortex and a larger surface area in key regions of the frontoparietal and default mode networks, which are involved in executive processing and creative thinking, respectively. The combination of reduced cortical thickness and larger surface area suggests above-age neural maturation of these networks in math-gifted individuals. Hum Brain Mapp 37:1893-1902, 2016. © 2016 Wiley Periodicals, Inc.

  16. Escitalopram Decreases Cross-Regional Functional Connectivity within the Default-Mode Network.

    Directory of Open Access Journals (Sweden)

    Vincent van de Ven

    Full Text Available The default-mode network (DMN, which comprises medial frontal, temporal and parietal regions, is part of the brain's intrinsic organization. The serotonergic (5-HT neurotransmitter system projects to DMN regions from midbrain efferents, and manipulation of this system could thus reveal insights into the neurobiological mechanisms of DMN functioning. Here, we investigate intrinsic functional connectivity of the DMN as a function of activity of the serotonergic system, through the administration of the selective serotonin reuptake inhibitor (SSRI escitalopram. We quantified DMN functional connectivity using an approach based on dual-regression. Specifically, we decomposed group data of a subset of the functional time series using spatial independent component analysis, and projected the group spatial modes to the same and an independent resting state time series of individual participants. We found no effects of escitalopram on global functional connectivity of the DMN at the map-level; that is, escitalopram did not alter the global functional architecture of the DMN. However, we found that escitalopram decreased DMN regional pairwise connectivity, which included anterior and posterior cingulate cortex, hippocampal complex and lateral parietal regions. Further, regional DMN connectivity covaried with alertness ratings across participants. Our findings show that escitalopram altered intrinsic regional DMN connectivity, which suggests that the serotonergic system plays an important role in DMN connectivity and its contribution to cognition. Pharmacological challenge designs may be a useful addition to resting-state functional MRI to investigate intrinsic brain functional organization.

  17. Structural connectivity of the default mode network and cognition in Alzheimer׳s disease.

    Science.gov (United States)

    Weiler, Marina; de Campos, Brunno Machado; Nogueira, Mateus Henrique; Pereira Damasceno, Benito; Cendes, Fernando; Balthazar, Marcio L F

    2014-07-30

    Disconnectivity between the Default Mode Network (DMN) nodes can cause clinical symptoms and cognitive deficits in Alzheimer׳s disease (AD). We aimed to examine the structural connectivity between DMN nodes, to verify the extent in which white matter disconnection affects cognitive performance. MRI data of 76 subjects (25 mild AD, 21 amnestic Mild Cognitive Impairment subjects and 30 controls) were acquired on a 3.0T scanner. ExploreDTI software (fractional Anisotropy threshold=0.25 and the angular threshold=60°) calculated axial, radial, and mean diffusivities, fractional anisotropy and streamline count. AD patients showed lower fractional anisotropy (P=0.01) and streamline count (P=0.029), and higher radial diffusivity (P=0.014) than controls in the cingulum. After correction for white matter atrophy, only fractional anisotropy and radial diffusivity remained significantly lower in AD compared to controls (P=0.003 and P=0.05). In the parahippocampal bundle, AD patients had lower mean and radial diffusivities (P=0.048 and P=0.013) compared to controls, from which only radial diffusivity survived for white matter adjustment (P=0.05). Regression models revealed that cognitive performance is also accounted for by white matter microstructural values. Structural connectivity within the DMN is important to the execution of high-complexity tasks, probably due to its relevant role in the integration of the network.

  18. Default mode, executive function, and language functional connectivity networks are compromised in mild Alzheimer's disease.

    Science.gov (United States)

    Weiler, Marina; Fukuda, Aya; Massabki, Lilian H P; Lopes, Tatila M; Franco, Alexandre R; Damasceno, Benito P; Cendes, Fernando; Balthazar, Marcio L F

    2014-03-01

    Alzheimer's disease (AD) is characterized by mental and cognitive problems, particularly with memory, language, visuospatial skills (VS), and executive functions (EF). Advances in the neuroimaging of AD have highlighted dysfunctions in functional connectivity networks (FCNs), especially in the memory related default mode network (DMN). However, little is known about the integrity and clinical significance of FNCs that process other cognitive functions than memory. We evaluated 22 patients with mild AD and 26 healthy controls through a resting state functional MRI scan. We aimed to identify different FCNs: the DMN, language, EF, and VS. Seed-based functional connectivity was calculated by placing a seed in the DMN (posterior cingulate cortex), language (Broca's and Wernicke's areas), EF (right and left dorsolateral prefrontal cortex), and VS networks (right and left associative visual cortex). We also performed regression analyses between individual connectivity maps for the different FCNs and the scores on cognitive tests. We found areas with significant decreases in functional connectivity in patients with mild AD in the DMN and Wernicke's area compared with controls. Increased connectivity in patients was observed in the EF network. Regarding multiple linear regression analyses, a significant correlation was only observed between the connectivity of the DMN and episodic memory (delayed recall) scores. In conclusion, functional connectivity alterations in mild AD are not restricted to the DMN. Other FCNs related to language and EF may be altered. However, we only found significant correlations between cognition and functional connectivity in the DMN and episodic memory performance.

  19. Methylphenidate remediates error-preceding activation of the default mode brain regions in cocaine addicted individuals

    Science.gov (United States)

    Matuskey, David; Luo, Xi; Zhang, Sheng; Morgan, Peter T.; Abdelghany, Osama; Malison, Robert T.; Li, Chiang-shan R.

    2013-01-01

    Many previous studies suggest the potential of psychostimulants in improving cognitive functioning. Our earlier pharmacological brain imaging study showed that intravenous methylphenidate (MPH) improves inhibitory control by altering cortico-striato-thalamic activations in cocaine dependent (CD) individuals. Here we provide additional evidence for the effects of MPH in restoring cerebral activations during cognitive performance. Ten CD individuals performed a stop signal task (SST) during functional magnetic resonance imaging (fMRI) in two sessions, in which either MPH (0.5 mg/Kg BW) or saline was administered intravenously. In the SST, a frequent go signal instructs participants to make a speeded response and a less frequent stop signal instructs them to withhold the response. Our previous work described increased activation of the precuneus/posterior cingulate cortex and ventromedial prefrontal cortex – regions of the default mode network (DMN) – before participants committed a stop error in healthy control but not CD individuals (Bednarski et al., 2011). The current results showed that, compared to saline, MPH restored error-preceding activations of DMN regions in CD individuals. The extent of the changes in precuneus activity was correlated with MPH-elicited increase in systolic blood pressure. These findings suggest that the influence of MPH on cerebral activations may extend beyond cognitive control and provide additional evidence warranting future studies to investigate the neural mechanisms and physiological markers of the efficacy of agonist therapy in cocaine dependence. PMID:23973363

  20. Static and dynamic posterior cingulate cortex nodal topology of default mode network predicts attention task performance.

    Science.gov (United States)

    Lin, Pan; Yang, Yong; Jovicich, Jorge; De Pisapia, Nicola; Wang, Xiang; Zuo, Chun S; Levitt, James Jonathan

    2016-03-01

    Characterization of the default mode network (DMN) as a complex network of functionally interacting dynamic systems has received great interest for the study of DMN neural mechanisms. In particular, understanding the relationship of intrinsic resting-state DMN brain network with cognitive behaviors is an important issue in healthy cognition and mental disorders. However, it is still unclear how DMN functional connectivity links to cognitive behaviors during resting-state. In this study, we hypothesize that static and dynamic DMN nodal topology is associated with upcoming cognitive task performance. We used graph theory analysis in order to understand better the relationship between the DMN functional connectivity and cognitive behavior during resting-state and task performance. Nodal degree of the DMN was calculated as a metric of network topology. We found that the static and dynamic posterior cingulate cortex (PCC) nodal degree within the DMN was associated with task performance (Reaction Time). Our results show that the core node PCC nodal degree within the DMN was significantly correlated with reaction time, which suggests that the PCC plays a key role in supporting cognitive function. PMID:25904156

  1. Functional Connectivity with the Default Mode Network Is Altered in Fibromyalgia Patients

    Science.gov (United States)

    Chiu, Yee; Nurmikko, Turo; Stancak, Andrej

    2016-01-01

    Fibromyalgia syndrome (FMS) patients show altered connectivity with the network maintaining ongoing resting brain activity, known as the default mode network (DMN). The connectivity patterns of DMN with the rest of the brain in FMS patients are poorly understood. This study employed seed-based functional connectivity analysis to investigate resting-state functional connectivity with DMN structures in FMS. Sixteen female FMS patients and 15 age-matched, healthy control subjects underwent T2-weighted resting-state MRI scanning and functional connectivity analyses using DMN network seed regions. FMS patients demonstrated alterations to connectivity between DMN structures and anterior midcingulate cortex, right parahippocampal gyrus, left superior parietal lobule and left inferior temporal gyrus. Correlation analysis showed that reduced functional connectivity between the DMN and the right parahippocampal gyrus was associated with longer duration of symptoms in FMS patients, whereas augmented connectivity between the anterior midcingulate and posterior cingulate cortices was associated with tenderness and depression scores. Our findings demonstrate alterations to functional connectivity between DMN regions and a variety of regions which are important for pain, cognitive and emotional processing in FMS patients, and which may contribute to the development or maintenance of chronic symptoms in FMS. PMID:27442504

  2. Brains striving for coherence: Long-term cumulative plot formation in the default mode network.

    Science.gov (United States)

    Tylén, K; Christensen, P; Roepstorff, A; Lund, T; Østergaard, S; Donald, M

    2015-11-01

    Many everyday activities, such as engaging in conversation or listening to a story, require us to sustain attention over a prolonged period of time while integrating and synthesizing complex episodic content into a coherent mental model. Humans are remarkably capable of navigating and keeping track of all the parallel social activities of everyday life even when confronted with interruptions or changes in the environment. However, the underlying cognitive and neurocognitive mechanisms of such long-term integration and profiling of information remain a challenge to neuroscience. While brain activity is generally traceable within the short time frame of working memory (milliseconds to seconds), these integrative processes last for minutes, hours or even days. Here we report two experiments on story comprehension. Experiment I establishes a cognitive dissociation between our comprehension of plot and incidental facts in narratives: when episodic material allows for long-term integration in a coherent plot, we recall fewer factual details. However, when plot formation is challenged, we pay more attention to incidental facts. Experiment II investigates the neural underpinnings of plot formation. Results suggest a central role for the brain's default mode network related to comprehension of coherent narratives while incoherent episodes rather activate the frontoparietal control network. Moreover, an analysis of cortical activity as a function of the cumulative integration of narrative material into a coherent story reveals to linear modulations of right hemisphere posterior temporal and parietal regions. Together these findings point to key neural mechanisms involved in the fundamental human capacity for cumulative plot formation.

  3. Transcatheter aortic valve implantation: the transfemoral access route is the default access.

    Science.gov (United States)

    Stortecky, Stefan; O'Sullivan, Crochan J; Buellesfeld, Lutz; Windecker, Stephan; Wenaweser, Peter

    2013-09-10

    Transcatheter aortic valve implantation (TAVI) is a widely accepted alternative to surgical aortic valve replacement (SAVR) among non-operable patients or selected high-risk patients with degenerative, severe aortic stenosis. TAVI is considered less invasive when compared with SAVR; however, there remain significant differences between different TAVI access routes. The transfemoral approach is considered the least invasive access route, and can be performed as a fully percutaneous procedure in a spontaneously breathing patient under local anaesthesia and mild sedation only. Moreover, transfemoral TAVI patients are typically transferred to coronary care rather than to an intensive care unit after the procedure, and benefit from early ambulation and a reduction in overall length of hospital stay. Considering these patient-specific and health-economic advantages, several TAVI centres follow the least invasive strategy for their patients and have implemented the transfemoral access route as the default access in their institutions. This article provides an overview on the prerequisites for a successful transfemoral TAVI procedure, describes the procedural advantages compared to alternative access routes, and highlights differences in clinical outcomes. PMID:24025952

  4. Development of the Default Mode and Central Executive Networks across early adolescence: A longitudinal study

    Directory of Open Access Journals (Sweden)

    Lauren E. Sherman

    2014-10-01

    Full Text Available The mature brain is organized into distinct neural networks defined by regions demonstrating correlated activity during task performance as well as rest. While research has begun to examine differences in these networks between children and adults, little is known about developmental changes during early adolescence. Using functional magnetic resonance imaging (fMRI, we examined the Default Mode Network (DMN and the Central Executive Network (CEN at ages 10 and 13 in a longitudinal sample of 45 participants. In the DMN, participants showed increasing integration (i.e., stronger within-network correlations between the posterior cingulate cortex (PCC and the medial prefrontal cortex. During this time frame participants also showed increased segregation (i.e., weaker between-network correlations between the PCC and the CEN. Similarly, from age 10 to 13, participants showed increased connectivity between the dorsolateral prefrontal cortex and other CEN nodes, as well as increasing DMN segregation. IQ was significantly positively related to CEN integration at age 10, and between-network segregation at both ages. These findings highlight early adolescence as a period of significant maturation for the brain's functional architecture and demonstrate the utility of longitudinal designs to investigate neural network development.

  5. The structural connectivity pattern of the default mode network and its association with memory and anxiety

    Directory of Open Access Journals (Sweden)

    Yan eTao

    2015-11-01

    Full Text Available The default mode network (DMN is one of the most widely studied resting state functional networks. The structural basis for the DMN is of particular interest and has been studied by several researchers using diffusion tensor imaging (DTI. Most of these previous studies focused on a few regions or white matter tracts of the DMN so that the global structural connectivity pattern and network properties of the DMN remain unclear. Moreover, evidences indicate that the DMN is involved in both memory and emotion, but how the DMN regulates memory and anxiety from the perspective of the whole DMN structural network remains unknown. We used multimodal neuroimaging methods to investigate the structural connectivity pattern of the DMN and the association of its network properties with memory and anxiety in 205 young healthy subjects. Using a probabilistic fiber tractography technique based on DTI data and graph theory methods, we constructed the global structural connectivity pattern of the DMN and found that memory quotient (MQ score was significantly positively correlated with the global and local efficiency of the DMN whereas anxiety was found to be negatively correlated with the efficiency. The strong structural connectivity between multiple brain regions within DMN may reflect that the DMN has certain structural basis. Meanwhile, we found the network efficiency of the DMN were related to memory and anxiety measures, which indicated that the DMN may play a role in the memory and anxiety.

  6. The psychedelic state induced by ayahuasca modulates the activity and connectivity of the default mode network.

    Directory of Open Access Journals (Sweden)

    Fernanda Palhano-Fontes

    Full Text Available The experiences induced by psychedelics share a wide variety of subjective features, related to the complex changes in perception and cognition induced by this class of drugs. A remarkable increase in introspection is at the core of these altered states of consciousness. Self-oriented mental activity has been consistently linked to the Default Mode Network (DMN, a set of brain regions more active during rest than during the execution of a goal-directed task. Here we used fMRI technique to inspect the DMN during the psychedelic state induced by Ayahuasca in ten experienced subjects. Ayahuasca is a potion traditionally used by Amazonian Amerindians composed by a mixture of compounds that increase monoaminergic transmission. In particular, we examined whether Ayahuasca changes the activity and connectivity of the DMN and the connection between the DMN and the task-positive network (TPN. Ayahuasca caused a significant decrease in activity through most parts of the DMN, including its most consistent hubs: the Posterior Cingulate Cortex (PCC/Precuneus and the medial Prefrontal Cortex (mPFC. Functional connectivity within the PCC/Precuneus decreased after Ayahuasca intake. No significant change was observed in the DMN-TPN orthogonality. Altogether, our results support the notion that the altered state of consciousness induced by Ayahuasca, like those induced by psilocybin (another serotonergic psychedelic, meditation and sleep, is linked to the modulation of the activity and the connectivity of the DMN.

  7. Mathematics anxiety reduces default mode network deactivation in response to numerical tasks

    Directory of Open Access Journals (Sweden)

    Belinda ePletzer

    2015-04-01

    Full Text Available Mathematics anxiety is negatively related to mathematics performance, thereby threatening the professional success. Preoccupation with the emotional content of the stimuli may consume working memory resources, which may be reflected in decreased deactivation of areas associated with the default mode network (DMN activated during self-referential and emotional processing. The common problem is that math anxiety is usually associated with poor math performance, so that any group differences are difficult to interpret.Here we compared the BOLD-response of 18 participants with high (HMAs and 18 participants with low mathematics anxiety (LMAs matched for their mathematical performance to two numerical tasks (number comparison, number bisection. During both tasks, we found stronger deactivation within the DMN in LMAs compared to HMAs, while BOLD-response in task-related activation areas did not differ between HMAs and LMAs. The difference in DMN deactivation between the HMA and LMA group was more pronounced in stimuli with additional requirement on inhibitory functions, but did not differ between number magnitude processing and arithmetic fact retrieval.

  8. Mathematics anxiety reduces default mode network deactivation in response to numerical tasks.

    Science.gov (United States)

    Pletzer, Belinda; Kronbichler, Martin; Nuerk, Hans-Christoph; Kerschbaum, Hubert H

    2015-01-01

    Mathematics anxiety is negatively related to mathematics performance, thereby threatening the professional success. Preoccupation with the emotional content of the stimuli may consume working memory resources, which may be reflected in decreased deactivation of areas associated with the default mode network (DMN) activated during self-referential and emotional processing. The common problem is that math anxiety is usually associated with poor math performance, so that any group differences are difficult to interpret. Here we compared the BOLD-response of 18 participants with high (HMAs) and 18 participants with low mathematics anxiety (LMAs) matched for their mathematical performance to two numerical tasks (number comparison, number bisection). During both tasks, we found stronger deactivation within the DMN in LMAs compared to HMAs, while BOLD-response in task-related activation areas did not differ between HMAs and LMAs. The difference in DMN deactivation between the HMA and LMA group was more pronounced in stimuli with additional requirement on inhibitory functions, but did not differ between number magnitude processing and arithmetic fact retrieval.

  9. Changes in default mode network as automaticity develops in a categorization task.

    Science.gov (United States)

    Shamloo, Farzin; Helie, Sebastien

    2016-10-15

    The default mode network (DMN) is a set of brain regions in which blood oxygen level dependent signal is suppressed during attentional focus on the external environment. Because automatic task processing requires less attention, development of automaticity in a rule-based categorization task may result in less deactivation and altered functional connectivity of the DMN when compared to the initial learning stage. We tested this hypothesis by re-analyzing functional magnetic resonance imaging data of participants trained in rule-based categorization for over 10,000 trials (Helie et al., 2010) [12,13]. The results show that some DMN regions are deactivated in initial training but not after automaticity has developed. There is also a significant decrease in DMN deactivation after extensive practice. Seed-based functional connectivity analyses with the precuneus, medial prefrontal cortex (two important DMN regions) and Brodmann area 6 (an important region in automatic categorization) were also performed. The results show increased functional connectivity with both DMN and non-DMN regions after the development of automaticity, and a decrease in functional connectivity between the medial prefrontal cortex and ventromedial orbitofrontal cortex. Together, these results further support the hypothesis of a strategy shift in automatic categorization and bridge the cognitive and neuroscientific conceptions of automaticity in showing that the reduced need for cognitive resources in automatic processing is accompanied by a disinhibition of the DMN and stronger functional connectivity between DMN and task-related brain regions. PMID:27457134

  10. Intrinsic architecture underlying the relations among the default, dorsal attention, and frontoparietal control networks of the human brain.

    Science.gov (United States)

    Spreng, R Nathan; Sepulcre, Jorge; Turner, Gary R; Stevens, W Dale; Schacter, Daniel L

    2013-01-01

    Human cognition is increasingly characterized as an emergent property of interactions among distributed, functionally specialized brain networks. We recently demonstrated that the antagonistic "default" and "dorsal attention" networks--subserving internally and externally directed cognition, respectively--are modulated by a third "frontoparietal control" network that flexibly couples with either network depending on task domain. However, little is known about the intrinsic functional architecture underlying this relationship. We used graph theory to analyze network properties of intrinsic functional connectivity within and between these three large-scale networks. Task-based activation from three independent studies were used to identify reliable brain regions ("nodes") of each network. We then examined pairwise connections ("edges") between nodes, as defined by resting-state functional connectivity MRI. Importantly, we used a novel bootstrap resampling procedure to determine the reliability of graph edges. Furthermore, we examined both full and partial correlations. As predicted, there was a higher degree of integration within each network than between networks. Critically, whereas the default and dorsal attention networks shared little positive connectivity with one another, the frontoparietal control network showed a high degree of between-network interconnectivity with each of these networks. Furthermore, we identified nodes within the frontoparietal control network of three different types--default-aligned, dorsal attention-aligned, and dual-aligned--that we propose play dissociable roles in mediating internetwork communication. The results provide evidence consistent with the idea that the frontoparietal control network plays a pivotal gate-keeping role in goal-directed cognition, mediating the dynamic balance between default and dorsal attention networks.

  11. Resting-State Glutamate and GABA Concentrations Predict Task-Induced Deactivation in the Default Mode Network

    OpenAIRE

    Hu, Yuzheng; Chen, Xi; Gu, Hong; Yang, Yihong

    2013-01-01

    Deactivation of the human brain's default mode network (DMN) is regarded as suppression of endogenous activity to support exogenous task-related processes. This phenomenon has important functional relevance and insufficient DMN deactivation has been implicated in several neuropsychiatric disorders. However, the neurochemical mechanism of the DMN′s deactivation remains largely unknown. In the present study, we test the hypothesis that the major excitatory and inhibitory neurotransmitters, glut...

  12. The chicken or the egg? A note on the dynamic interrelation between government bond spreads and credit default swaps

    OpenAIRE

    Delis, Manthos D; Mylonidis, Nikolaos

    2010-01-01

    This note provides the first empirical assessment of the dynamic interrelation between government bond spreads and their associated credit default swaps (CDS). We use data for the Southern European countries (Greece, Italy, Portugal and Spain) that found themselves with a problematic public sector in the dawn of the recent financial distress. We find that CDS prices Granger-cause government bond spreads after the eruption of the 2007 subprime crisis. Feedback causality is detected during peri...

  13. Credit derivatives: instruments of hedging and factors of instability. The example of ?Credit Default Swaps? on French reference entities

    OpenAIRE

    Rey, Nathalie

    2009-01-01

    Through a long-period analysis of the inter-temporal relations between the French markets for credit default swaps (CDS), shares and bonds between 2001 and 2008, this article shows how a financial innovation like CDS could heighten financial instability. After describing the operating principles of credit derivatives in general and CDS in particular, we construct two difference VAR models on the series: the share return rates, the variation in bond spreads and the variation in CDS spreads for...

  14. Optimal trade credit and order quantity when trade credit impacts on both demand rate and default risk

    OpenAIRE

    K-R Lou; W-C Wang

    2013-01-01

    In practice, to attract new buyers and to avoid lasting price competition, a seller frequently offers its buyers a permissible delay in payment (ie, trade credit). However, the policy of granting a permissible delay in payment adds an additional dimension of default risk to the seller. In contrast to previous researchers for finding optimal solutions to buyers, we first propose an economic order quantity model from the seller's prospective to determine its optimal trade credit and order quant...

  15. Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness

    Directory of Open Access Journals (Sweden)

    Nicholas D. Lant

    2016-01-01

    Full Text Available The specific neural bases of disorders of consciousness (DOC are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale—Revised (CRS-R scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network – and most importantly the precuneus – and the anterior forebrain mesocircuit in the neural basis of the DOC.

  16. Whatever the customer wants, the customer gets? Exploring the gap between consumer preferences and default electricity products in Germany

    International Nuclear Information System (INIS)

    In liberalized electricity markets, residential customers can choose their preferred provider and select among a variety of different electricity products, including green power options. Successful product design and marketing strategies for green electricity may provide electricity providers with a competitive advantage, while at the same time contributing to energy policy objectives. This requires, however, a thorough understanding of customer preferences. We investigate the relative importance of different product attributes in creating customer value, and find that price and electricity mix are the two most important attributes. The German electricity customers we surveyed in 2009 expressed an implicit willingness to pay a premium of about 16% for electricity from renewable sources. We conclude that consumers are willing to pay a significant price premium for an upgrade from the current default electricity mix in Germany to a more environmentally friendly default electricity mix, and discuss implications for marketing strategy and energy policy. Our findings are based on a dataset of 4968 experimental choices made by 414 German residential consumers, collected in a stated preference survey. - Highlights: ► Study is based on 4968 experimental choices made by 414 German retail consumers. ► Apart from price, the electricity mix is the most important product attribute. ► Majority of consumers prefer nuclear-free electricity. ► Respondents are willing to pay a premium for green electricity. ► German default electricity mix does not correspond to current customer preferences.

  17. Effects of Ganglioside on Working Memory and the Default Mode Network in Individuals with Subjective Cognitive Impairment: A Randomized Controlled Trial.

    Science.gov (United States)

    Jeon, Yujin; Kim, Binna; Kim, Jieun E; Kim, Bori R; Ban, Soonhyun; Jeong, Jee Hyang; Kwon, Oran; Rhie, Sandy Jeong; Ahn, Chang-Won; Kim, Jong-Hoon; Jung, Sung Ug; Park, Soo-Hyun; Lyoo, In Kyoon; Yoon, Sujung

    2016-01-01

    This randomized, double-blind, placebo-controlled trial examined whether the administration of ganglioside, an active ingredient of deer bone extract, can improve working memory performance by increasing gray matter volume and functional connectivity in the default mode network (DMN) in individuals with subjective cognitive impairment. Seventy-five individuals with subjective cognitive impairment were chosen to receive either ganglioside (330[Formula: see text][Formula: see text]g/day or 660[Formula: see text][Formula: see text]g/day) or a placebo for 8 weeks. Changes in working memory performance with treatment of either ganglioside or placebo were assessed as cognitive outcome measures. Using voxel-based morphometry and functional connectivity analyses, changes in gray matter volume and functional connectivity in the DMN were also assessed as brain outcome measures. Improvement in working memory performance was greater in the ganglioside group than in the placebo group. The ganglioside group, relative to the placebo group, showed greater increases in gray matter volume and functional connectivity in the DMN. A significant relationship between increased functional connectivity of the precuneus and improved working memory performance was observed in the ganglioside group. The current findings suggest that ganglioside has cognitive-enhancing effects in individuals with subjective cognitive impairment. Ganglioside-induced increases in gray matter volume and functional connectivity in the DMN may partly be responsible for the potential nootropic effects of ganglioside. The clinical trial was registered with ClinicalTrials.gov (identifier: NCT02379481). PMID:27109158

  18. Cocaine addiction related reproducible brain regions of abnormal default-mode network functional connectivity: a group ICA study with different model orders.

    Science.gov (United States)

    Ding, Xiaoyu; Lee, Seong-Whan

    2013-08-26

    Model order selection in group independent component analysis (ICA) has a significant effect on the obtained components. This study investigated the reproducible brain regions of abnormal default-mode network (DMN) functional connectivity related with cocaine addiction through different model order settings in group ICA. Resting-state fMRI data from 24 cocaine addicts and 24 healthy controls were temporally concatenated and processed by group ICA using model orders of 10, 20, 30, 40, and 50, respectively. For each model order, the group ICA approach was repeated 100 times using the ICASSO toolbox and after clustering the obtained components, centrotype-based anterior and posterior DMN components were selected for further analysis. Individual DMN components were obtained through back-reconstruction and converted to z-score maps. A whole brain mixed effects factorial ANOVA was performed to explore the differences in resting-state DMN functional connectivity between cocaine addicts and healthy controls. The hippocampus, which showed decreased functional connectivity in cocaine addicts for all the tested model orders, might be considered as a reproducible abnormal region in DMN associated with cocaine addiction. This finding suggests that using group ICA to examine the functional connectivity of the hippocampus in the resting-state DMN may provide an additional insight potentially relevant for cocaine-related diagnoses and treatments. PMID:23707901

  19. The self-pleasantness judgment modulates the encoding performance and the Default Mode Network activity

    Directory of Open Access Journals (Sweden)

    Perrone-Bertolotti eMarcela

    2016-03-01

    Full Text Available In this functional magnetic resonance imaging (fMRI study, we evaluated the effect of self-relevance on cerebral activity and behavioral performance during an incidental encoding task. Recent findings suggest that pleasantness judgments reliably induce self-oriented (internal thoughts and increase default mode network (DMN activity. We hypothesized that this increase in DMN activity would relate to increased memory recognition for pleasantly-judged stimuli (which depend on internally-oriented attention but decreased recognition for unpleasantly-judged items (which depend on externally-oriented attention. To test this hypothesis, brain activity was recorded from 21 healthy participants while they performed a pleasantness judgment requiring them to rate visual stimuli as pleasant or unpleasant. One hour later, participants performed a surprise memory recognition test outside of the scanner. Thus, we were able to evaluate the effects of pleasant and unpleasant judgments on cerebral activity and incidental encoding. The behavioral results showed that memory recognition was better for items rated as pleasant than items rated as unpleasant. The whole brain analysis indicated that successful encoding activates the inferior frontal and lateral temporal cortices, whereas unsuccessful encoding recruits two key medial posterior DMN regions, the posterior cingulate cortex and precuneus. A region of interest analysis including classic DMN areas, revealed significantly greater involvement of the medial Prefrontal Cortex in pleasant compared to unpleasant judgments, suggesting this region’s involvement in self-referential (i.e., internal processing. This area may be responsible for the greater recognition performance seen for pleasant stimuli. Furthermore, a significant interaction between the encoding performance (successful vs. unsuccessful and pleasantness was observed for the posterior cingulate cortex, precuneus and inferior frontal gyrus. Overall, our

  20. Sleep disturbance in mild cognitive impairment is associated with alterations in the brain's default mode network.

    Science.gov (United States)

    McKinnon, Andrew C; Lagopoulos, Jim; Terpening, Zoe; Grunstein, Ron; Hickie, Ian B; Batchelor, Jennifer; Lewis, Simon J G; Duffy, Shantel; Shine, James M; Naismith, Sharon L

    2016-06-01

    This study aimed to identify default mode network (DMN) functional connectivity deficits in patients with mild cognitive impairment (MCI) and sleep disturbance, relative to those with MCI and no sleep disturbance. A control group was included to aid in identifying DMN changes specific to MCI. A cross-sectional, single-center study was performed at the Brain and Mind Research Centre in Sydney, Australia. Participants (95 adults over the age of 65: 38 controls and 57 meeting criteria for MCI) underwent resting-state functional MRI along with comprehensive neuropsychological, medical, and psychiatric assessment. Self-report data were collected including sleep quality assessment via the Pittsburgh Sleep Quality Index. A total score of greater than 5 on the Pittsburgh Sleep Quality Index was used to signify the presence of significant sleep disturbance, as per commonly used methodology. Using this criterion, 53% (n = 30) of our MCI group were classified as sleep-disturbed. Whereas the total group of MCI subjects and controls demonstrated no significant differences, sleep-disturbed MCIs demonstrated increased connectivity between temporal and parietal regions, and decreased connectivity between the prefrontal cortex and the temporoparietal junction relative to sleep-disturbed controls. Relative to those MCIs without sleep disturbance, sleep-disturbed MCI participants demonstrated significantly diminished DMN connectivity between temporal and parietal regions, a finding that was particularly pronounced in amnestic MCI. Sleep disturbance in MCI is associated with distinct alterations in DMN functional connectivity in brain regions underpinning salient memory and sleep systems. Future studies may build on these results via experimental manipulation and objective measurement of sleep. (PsycINFO Database Record PMID:26963234

  1. The default mode network and social understanding of others: what do brain connectivity studies tell us.

    Science.gov (United States)

    Li, Wanqing; Mai, Xiaoqin; Liu, Chao

    2014-01-01

    The Default Mode Network (DMN) has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common results show that the medial prefrontal cortex (MPFC) plays a key role in the social understanding of others, and the subregions of the MPFC contribute differently to this function according to their roles in different subsystems of the DMN. At the bottom, the ventral MPFC in the medial temporal lobe (MTL) subsystem and its connections with emotion regions are mainly associated with emotion engagement during social interactions. Above, the anterior MPFC (aMPFC) in the cortical midline structures (CMS) and its connections with posterior and anterior cingulate cortex contribute mostly to making self-other distinctions. At the top, the dorsal MPFC (dMPFC) in the dMPFC subsystem and its connection with the temporo-parietal junction (TPJ) are primarily related to the understanding of other's mental states. As behaviors become more complex, the related regions in frontal cortex are located higher. This reflects the transfer of information processing from automatic to cognitive processes with the increase of the complexity of social interaction. Besides the MPFC and TPJ, the connectivities of posterior cingulate cortex (PCC) also show some changes during tasks from the four social fields. These results indicate that the DMN is indispensable in the social understanding of others. PMID:24605094

  2. Temporal Dynamics of the Default Mode Network Characterize Meditation-Induced Alterations in Consciousness.

    Science.gov (United States)

    Panda, Rajanikant; Bharath, Rose D; Upadhyay, Neeraj; Mangalore, Sandhya; Chennu, Srivas; Rao, Shobini L

    2016-01-01

    Current research suggests that human consciousness is associated with complex, synchronous interactions between multiple cortical networks. In particular, the default mode network (DMN) of the resting brain is thought to be altered by changes in consciousness, including the meditative state. However, it remains unclear how meditation alters the fast and ever-changing dynamics of brain activity within this network. Here we addressed this question using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to compare the spatial extents and temporal dynamics of the DMN during rest and meditation. Using fMRI, we identified key reductions in the posterior cingulate hub of the DMN, along with increases in right frontal and left temporal areas, in experienced meditators during rest and during meditation, in comparison to healthy controls (HCs). We employed the simultaneously recorded EEG data to identify the topographical microstate corresponding to activation of the DMN. Analysis of the temporal dynamics of this microstate revealed that the average duration and frequency of occurrence of DMN microstate was higher in meditators compared to HCs. Both these temporal parameters increased during meditation, reflecting the state effect of meditation. In particular, we found that the alteration in the duration of the DMN microstate when meditators entered the meditative state correlated negatively with their years of meditation experience. This reflected a trait effect of meditation, highlighting its role in producing durable changes in temporal dynamics of the DMN. Taken together, these findings shed new light on short and long-term consequences of meditation practice on this key brain network. PMID:27499738

  3. Art reaches within: aesthetic experience, the self and the default mode network

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    Edward A Vessel

    2013-12-01

    Full Text Available In a task of rating images of artworks in an fMRI scanner, regions in the medial prefrontal cortex that are known to be part of the default mode network (DMN were positively activated on the highest-rated trials. This is surprising given the DMN's original characterization as the set of brain regions that show greater fMRI activity during rest periods than during performance of tasks requiring focus on external stimuli. But further research showed that DMN regions could be positively activated also in structured tasks, if those tasks involved self-referential thought or self-relevant information. How may our findings be understood in this context? Although our task had no explicit self-referential aspect and the stimuli had no a priori self-relevance to the observers, the experimental design we employed emphasized the personal aspects of aesthetic experience. Observers were told that we were interested in their individual tastes, and asked to base their ratings on how much each artwork "moved" them. Moreover, we used little-known artworks that covered a wide range of styles, which led to high individual variability: each artwork was rated highly by some observers and poorly by others. This means that rating-specific neural responses cannot be attributed to the features of any particular artworks, but rather to the aesthetic experience itself. The DMN activity therefore suggests that certain artworks, albeit unfamiliar, may be so well-matched to an individual’s unique makeup that they obtain access to the neural substrates concerned with the self – access which other external stimuli normally do not get. This mediates a sense of being moved, or touched from within. This account is consistent with the modern notion that individuals’ taste in art is linked with their sense of identity, and suggests that DMN activity may serve to signal self-relevance in a broader sense than has been thought so far.

  4. The Default Mode Network and Social Understanding of Others: What do Brain Connectivity Studies Tell Us

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    Wanqing eLi

    2014-02-01

    Full Text Available The Default Mode Network (DMN has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common results show that the medial prefrontal cortex (MPFC plays a key role in the social understanding of others, and the subregions of the MPFC contribute differently to this function according to their roles in different subsystems of the DMN. At the bottom, the ventral MPFC in the medial temporal lobe subsystem and its connections with emotion regions are mainly associated with emotion engagement during social interactions. Above, the anterior MPFC (aMPFC in the cortical midline structures and its connections with posterior and anterior cingulate cortex contribute mostly to making self-other distinctions. At the top, the dorsal MPFC (dMPFC in the dMPFC subsystem and its connection with the temporo-parietal junction (TPJ are primarily related to the understanding of other’s mental states. As behaviors become more complex, the related regions in frontal cortex are located higher. This reflects the transfer of information processing from automatic to cognitive processes with the increase of the complexity of social interaction. Besides the MPFC and TPJ, the connectivities of posterior cingulate cortex also show some changes during tasks from the four social fields. These results indicate that the DMN is indispensable in the social understanding of others.

  5. Differential deactivation during mentalizing and classification of autism based on default mode network connectivity.

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    Donna L Murdaugh

    Full Text Available The default mode network (DMN is a collection of brain areas found to be consistently deactivated during task performance. Previous neuroimaging studies of resting state have revealed reduced task-related deactivation of this network in autism. We investigated the DMN in 13 high-functioning adults with autism spectrum disorders (ASD and 14 typically developing control participants during three fMRI studies (two language tasks and a Theory-of-Mind (ToM task. Each study had separate blocks of fixation/resting baseline. The data from the task blocks and fixation blocks were collated to examine deactivation and functional connectivity. Deficits in the deactivation of the DMN in individuals with ASD were specific only to the ToM task, with no group differences in deactivation during the language tasks or a combined language and self-other discrimination task. During rest blocks following the ToM task, the ASD group showed less deactivation than the control group in a number of DMN regions, including medial prefrontal cortex (MPFC, anterior cingulate cortex, and posterior cingulate gyrus/precuneus. In addition, we found weaker functional connectivity of the MPFC in individuals with ASD compared to controls. Furthermore, we were able to reliably classify participants into ASD or typically developing control groups based on both the whole-brain and seed-based connectivity patterns with accuracy up to 96.3%. These findings indicate that deactivation and connectivity of the DMN were altered in individuals with ASD. In addition, these findings suggest that the deficits in DMN connectivity could be a neural signature that can be used for classifying an individual as belonging to the ASD group.

  6. The influence of rest period instructions on the default mode network

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    Christopher eBenjamin

    2010-12-01

    Full Text Available The default mode network (DMN refers to regional brain activity that is greater during rest periods than during attention-demanding tasks and many studies have reported DMN alterations in patient populations. It has also been shown that the DMN is suppressed by scanner background noise (SBN, which is the noise produced by functional magnetic resonance imaging (fMRI. However, it is unclear whether different approaches to rest in the noisy MR environment can alter the DMN and constitute a confound in studies investigating the DMN in particular patient populations (e.g., individuals with schizophrenia, Alzheimer’s disease. We examined twenty-seven healthy adult volunteers who completed an fMRI experiment with 3 different instructions for rest: (1 relax and be still, (2 attend to SBN, or (3 ignore SBN. Region of interest (ROI analyses were performed to determine the influence of rest period instructions on core regions of the DMN and DMN regions previously reported to be altered in patients with or at risk for Alzheimer’s disease or schizophrenia. The dorsal medial prefrontal cortex (dmPFC exhibited greater activity when specific resting instructions were given (i.e. attend to or ignore SBN compared to when non-specific resting instructions were given. Condition-related differences in connectivity were also observed between regions of the dmPFC and inferior parietal/posterior superior temporal cortex. We conclude that rest period instructions and SBN levels should be carefully considered for fMRI studies on the DMN, especially studies on clinical populations and groups that may have different approaches to rest, such as first-time research participants and children.

  7. Temporal Dynamics of the Default Mode Network Characterize Meditation-Induced Alterations in Consciousness

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    Panda, Rajanikant; Bharath, Rose D.; Upadhyay, Neeraj; Mangalore, Sandhya; Chennu, Srivas; Rao, Shobini L.

    2016-01-01

    Current research suggests that human consciousness is associated with complex, synchronous interactions between multiple cortical networks. In particular, the default mode network (DMN) of the resting brain is thought to be altered by changes in consciousness, including the meditative state. However, it remains unclear how meditation alters the fast and ever-changing dynamics of brain activity within this network. Here we addressed this question using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) to compare the spatial extents and temporal dynamics of the DMN during rest and meditation. Using fMRI, we identified key reductions in the posterior cingulate hub of the DMN, along with increases in right frontal and left temporal areas, in experienced meditators during rest and during meditation, in comparison to healthy controls (HCs). We employed the simultaneously recorded EEG data to identify the topographical microstate corresponding to activation of the DMN. Analysis of the temporal dynamics of this microstate revealed that the average duration and frequency of occurrence of DMN microstate was higher in meditators compared to HCs. Both these temporal parameters increased during meditation, reflecting the state effect of meditation. In particular, we found that the alteration in the duration of the DMN microstate when meditators entered the meditative state correlated negatively with their years of meditation experience. This reflected a trait effect of meditation, highlighting its role in producing durable changes in temporal dynamics of the DMN. Taken together, these findings shed new light on short and long-term consequences of meditation practice on this key brain network. PMID:27499738

  8. The default mode network and EEG α oscillations: an independent component analysis.

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    Knyazev, Gennady G; Slobodskoj-Plusnin, Jaroslav Y; Bocharov, Andrey V; Pylkova, Liudmila V

    2011-07-21

    The default mode network (DMN) has been principally investigated using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) and has received mixed support in electroencephalographic (EEG) studies. In particular, the existing evidence is too inconsistent to allow formulation of specific hypotheses linking DMN activity to traditional EEG frequency bands. In this study, we aimed to test whether blind decomposition methods are able to identify in EEG data spatial patterns resembling the DMN as it is described in PET and fMRI studies. Further we aimed to test a degree of task-relatedness of DMN patterns identified in the traditional EEG frequency bands. To answer these questions we collected data both in a resting state and during performance of two experimental tasks: an explicit judgment of facial affect and a social game task. Individual differences in amount of self-referential thoughts during the resting state were measured by a short self-report scale. Only alpha band spatial patterns simultaneously showed a considerable overlap with the DMN and high correlations with presumptive DMN function-related outcomes both in the resting state and during the social game task. Spontaneous self-referential thoughts were associated with enhanced alpha activity in the posterior DMN hub, whereas processing of DMN function-related external stimuli disrupted this activity and simultaneously caused partial alpha phase-locking to external events. This evidence implies that synchronization of internal mental processes, as opposed to the processing of external stimuli, might be the primary function of alpha oscillations which is bound to be related to activity of the DMN. PMID:21683942

  9. Disrupted functional connectivity of cerebellar default network areas in attention-deficit/hyperactivity disorder.

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    Kucyi, Aaron; Hove, Michael J; Biederman, Joseph; Van Dijk, Koene R A; Valera, Eve M

    2015-09-01

    Attention-deficit/hyperactivity disorder (ADHD) is increasingly understood as a disorder of spontaneous brain-network interactions. The default mode network (DMN), implicated in ADHD-linked behaviors including mind-wandering and attentional fluctuations, has been shown to exhibit abnormal spontaneous functional connectivity (FC) within-network and with other networks (salience, dorsal attention and frontoparietal) in ADHD. Although the cerebellum has been implicated in the pathophysiology of ADHD, it remains unknown whether cerebellar areas of the DMN (CerDMN) exhibit altered FC with cortical networks in ADHD. Here, 23 adults with ADHD and 23 age-, IQ-, and sex-matched controls underwent resting state fMRI. The mean time series of CerDMN areas was extracted, and FC with the whole brain was calculated. Whole-brain between-group differences in FC were assessed. Additionally, relationships between inattention and individual differences in FC were assessed for between-group interactions. In ADHD, CerDMN areas showed positive FC (in contrast to average FC in the negative direction in controls) with widespread regions of salience, dorsal attention and sensorimotor networks. ADHD individuals also exhibited higher FC (more positive correlation) of CerDMN areas with frontoparietal and visual network regions. Within the control group, but not in ADHD, participants with higher inattention had higher FC between CerDMN and regions in the visual and dorsal attention networks. This work provides novel evidence of impaired CerDMN coupling with cortical networks in ADHD and highlights a role of cerebro-cerebellar interactions in cognitive function. These data provide support for the potential targeting of CerDMN areas for therapeutic interventions in ADHD. PMID:26109476

  10. Default mode network connectivity as a function of familial and environmental risk for psychotic disorder.

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    Sanne C T Peeters

    Full Text Available Research suggests that altered interregional connectivity in specific networks, such as the default mode network (DMN, is associated with cognitive and psychotic symptoms in schizophrenia. In addition, frontal and limbic connectivity alterations have been associated with trauma, drug use and urban upbringing, though these environmental exposures have never been examined in relation to DMN functional connectivity in psychotic disorder.Resting-state functional MRI scans were obtained from 73 patients with psychotic disorder, 83 non-psychotic siblings of patients with psychotic disorder and 72 healthy controls. Posterior cingulate cortex (PCC seed-based correlation analysis was used to estimate functional connectivity within the DMN. DMN functional connectivity was examined in relation to group (familial risk, group × environmental exposure (to cannabis, developmental trauma and urbanicity and symptomatology.There was a significant association between group and PCC connectivity with the inferior parietal lobule (IPL, the precuneus (PCu and the medial prefrontal cortex (MPFC. Compared to controls, patients and siblings had increased PCC connectivity with the IPL, PCu and MPFC. In the IPL and PCu, the functional connectivity of siblings was intermediate to that of controls and patients. No significant associations were found between DMN connectivity and (subclinical psychotic/cognitive symptoms. In addition, there were no significant interactions between group and environmental exposures in the model of PCC functional connectivity.Increased functional connectivity in individuals with (increased risk for psychotic disorder may reflect trait-related network alterations. The within-network "connectivity at rest" intermediate phenotype was not associated with (subclinical psychotic or cognitive symptoms. The association between familial risk and DMN connectivity was not conditional on environmental exposure.

  11. APOE Effects on Default Mode Network in Chinese Cognitive Normal Elderly: Relationship with Clinical Cognitive Performance.

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    Haiqing Song

    Full Text Available Functional connectivity in default mode network (DMN may be changed in Alzheimer's disease (AD patients and related risk populations, such as amnestic mild cognitive impairment (aMCI patients and APOE ε4 carriers. Exploring DMN changes and related behavioral performance of APOE ε4 population might provide valuable evidence for better understanding the development of AD.Subjects were enrolled from a population-based cohort established in a multi-center study in China. Forty-nine cognitive normal individuals were enrolled after standardized cognitive evaluations, MRI examination and APOE genotyping. Regions of interest (ROI-based functional connectivity analyses were performed, and voxel-based analyses were used to validate these findings. The correlation between DMN functional connectivity and behavioral performance was further evaluated between APOE ε4ε3 and ε3ε3 carriers.Comparing to ε3ε3 carriers, functional connectivity between left parahippocampal gyrus and right superior frontal cortex (LPHC-R.Sup.F, left parahippocampal gyrus and medial prefrontal cortex (ventral (LPHC-vMPFC were significantly increased in ε4ε3 carriers, while connectivity between cerebellar tonsils and retrosplenial was decreased. LPHC-R.Sup.F connectivity was positively correlated with the changes of delay recall from baseline to follow-up (r = 0.768, p = 0.009, while LPHC-vMPFC connectivity had a positive correlation with MMSE at baseline (r = 0.356, p = 0.018, and a negative correlation with long-delayed recognition at follow-up (r = -0.677, p = 0.031. Significantly increased functional connectivity in vMPFC was confirmed in voxel-based analyses by taking LPHC as seed region.APOE ε4 carriers present both increased and decreased functional connectivity in DMN, which is correlated with clinical cognitive performances. DMN changes might be an early sign for cognitive decline.

  12. Deficits in episodic memory retrieval reveal impaired default mode network connectivity in amnestic mild cognitive impairment

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    Cameron J. Dunn

    2014-01-01

    Full Text Available Amnestic mild cognitive impairment (aMCI is believed to represent a transitional stage between normal healthy ageing and the development of dementia. In particular, aMCI patients have been shown to have higher annual transition rates to Alzheimer's Disease (AD than individuals without cognitive impairment. Despite intensifying interest investigating the neuroanatomical basis of this transition, there remain a number of questions regarding the pathophysiological process underlying aMCI itself. A number of recent studies in aMCI have shown specific impairments in connectivity within the default mode network (DMN, which is a group of regions strongly related to episodic memory capacities. However to date, no study has investigated the integrity of the DMN between patients with aMCI and those with a non-amnestic pattern of MCI (naMCI, who have cognitive impairment, but intact memory storage systems. In this study, we contrasted the DMN connectivity in 24 aMCI and 33 naMCI patients using seed-based resting state fMRI. The two groups showed no statistical difference in their DMN intra-connectivity. However when connectivity was analysed according to performance on measures of episodic memory retrieval, the two groups were separable, with aMCI patients demonstrating impaired functional connectivity between the hippocampal formation and the posterior cingulate cortex. We provide evidence that this lack of connectivity is driven by impaired communication from the posterior cingulate hub and does not simply represent hippocampal atrophy, suggesting that posterior cingulate degeneration is the driving force behind impaired DMN connectivity in aMCI.

  13. The default mode network and EEG regional spectral power: a simultaneous fMRI-EEG study.

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    Irene Neuner

    Full Text Available Electroencephalography (EEG frequencies have been linked to specific functions as an "electrophysiological signature" of a function. A combination of oscillatory rhythms has also been described for specific functions, with or without predominance of one specific frequency-band. In a simultaneous fMRI-EEG study at 3 T we studied the relationship between the default mode network (DMN and the power of EEG frequency bands. As a methodological approach, we applied Multivariate Exploratory Linear Optimized Decomposition into Independent Components (MELODIC and dual regression analysis for fMRI resting state data. EEG power for the alpha, beta, delta and theta-bands were extracted from the structures forming the DMN in a region-of-interest approach by applying Low Resolution Electromagnetic Tomography (LORETA. A strong link between the spontaneous BOLD response of the left parahippocampal gyrus and the delta-band extracted from the anterior cingulate cortex was found. A positive correlation between the beta-1 frequency power extracted from the posterior cingulate cortex (PCC and the spontaneous BOLD response of the right supplementary motor cortex was also established. The beta-2 frequency power extracted from the PCC and the precuneus showed a positive correlation with the BOLD response of the right frontal cortex. Our results support the notion of beta-band activity governing the "status quo" in cognitive and motor setup. The highly significant correlation found between the delta power within the DMN and the parahippocampal gyrus is in line with the association of delta frequencies with memory processes. We assumed "ongoing activity" during "resting state" in bringing events from the past to the mind, in which the parahippocampal gyrus is a relevant structure. Our data demonstrate that spontaneous BOLD fluctuations within the DMN are associated with different EEG-bands and strengthen the conclusion that this network is characterized by a specific

  14. Aberrant default-mode functional and structural connectivity in heroin-dependent individuals.

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    Xiaofen Ma

    Full Text Available Little is known about connectivity within the default mode network (DMN in heroin-dependent individuals (HDIs. In the current study, diffusion-tensor imaging (DTI and resting-state functional MRI (rs-fMRI were combined to investigate both structural and functional connectivity within the DMN in HDIs.Fourteen HDIs and 14 controls participated in the study. Structural (path length, tracts count, (fractional anisotropy FA and (mean diffusivity MD derived from DTI tractographyand functional (temporal correlation coefficient derived from rs-fMRI DMN connectivity changes were examined in HDIs. Pearson correlation analysis was performed to compare the structural/functional indices and duration of heroin use/Iowa gambling task(IGT performance in HDIs.HDIs had lower FA and higher MD in the tract connecting the posterior cingulate cortex/precuneus (PCC/PCUN to right parahippocampal gyrus (PHG, compared to the controls. HDIs also had decreased FA and track count in the tract connecting the PCC/PCUN and medial prefrontal cortex (MPFC, as well as decreased functional connectivity between the PCC/PCUN and bilateral PHG and MPFC, compared to controls. FA values for the tract connecting PCC/PCUN to the right PHG and connecting PCC/PCUN to the MPFC were negatively correlated to the duration of heroin use. The temporal correlation coefficients between the PCC/PCUN and the MPFC, and the FA values for the tract connecting the PCC/PCUN to the MPFC were positively correlated to IGT performance in HDIs.Structural and functional connectivity within the DMN are both disturbed in HDIs. This disturbance progresses as duration of heroin use increases and is related to deficits in decision making in HDIs.

  15. Connectivity of default-mode network is associated with cerebral edema in hepatic encephalopathy.

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    Wei-Che Lin

    Full Text Available Cerebral edema, a well-known feature of acute liver disease, can occur in cirrhotic patients regardless of hepatic encephalopathy (HE and adversely affect prognosis. This study characterized and correlated functional HE abnormalities in the brain to cerebral edema using resting-state functional magnetic resonance imaging (rs-fMRI and diffusion tensor imaging (DTI. Forty-one cirrhotic patients (16 without HE, 14 minimal HE, 11 overt HE and 32 healthy controls were assessed. The HE grade in cirrhotic patients was evaluated by the West Haven criteria and neuro-psychological examinations. Functional connectivity correlation coefficient (fc-CC of the default mode network (DMN was determined by rs-fMRI, while the corresponding mean diffusivity (MD was obtained from DTI. Correlations among inter-cortical fc-CC, DTI indices, Cognitive Ability Screening Instrument scores, and laboratory tests were also analyzed. Results showed that gradual reductions of HE-related consciousness levels, from "without HE" or "minimal HE" to "overt HE", correlated with decreased anterior-posterior fc-CC in DMN [F(4.415, p = 0.000]. The MD values from regions with anterior-posterior fc-CC differences in DMN revealed significant differences between the overt HE group and other groups. Increased MD in this network was inversely associated with decreased fc-CC in DMN and linearly correlated with poor cognitive performance. In conclusion, cerebral edema can be linked to altered cerebral temporal architecture that modifies both within- and between-network connectivity in HE. Reduced fc-CC in DMN is associated with behavior and consciousness deterioration. Through appropriate targets, rs-fMRI technology may provide relevant supplemental information for monitoring HE and serve as a new biomarker for clinical diagnosis.

  16. Dopamine transporters in striatum correlate with deactivation in the default mode network during visuospatial attention.

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    Dardo Tomasi

    Full Text Available BACKGROUND: Dopamine and dopamine transporters (DAT, which regulate extracellular dopamine in the brain are implicated in the modulation of attention but their specific roles are not well understood. Here we hypothesized that dopamine modulates attention by facilitation of brain deactivation in the default mode network (DMN. Thus, higher striatal DAT levels, which would result in an enhanced clearance of dopamine and hence weaker dopamine signals, would be associated to lower deactivation in the DMN during an attention task. METHODOLOGY/PRINCIPAL FINDINGS: For this purpose we assessed the relationship between DAT in striatum (measured with positron emission tomography and [(11C]cocaine used as DAT radiotracer and brain activation and deactivation during a parametric visual attention task (measured with blood oxygenation level dependent functional magnetic resonance imaging in healthy controls. We show that DAT availability in caudate and putamen had a negative correlation with deactivation in ventral parietal regions of the DMN (precuneus, BA 7 and a positive correlation with deactivation in a small region in the ventral anterior cingulate gyrus (BA 24/32. With increasing attentional load, DAT in caudate showed a negative correlation with load-related deactivation increases in precuneus. CONCLUSIONS/SIGNIFICANCE: These findings provide evidence that dopamine transporters modulate neural activity in the DMN and anterior cingulate gyrus during visuospatial attention. Our findings suggest that dopamine modulates attention in part by regulating neuronal activity in posterior parietal cortex including precuneus (region involved in alertness and cingulate gyrus (region deactivated in proportion to emotional interference. These findings suggest that the beneficial effects of stimulant medications (increase dopamine by blocking DAT in inattention reflect in part their ability to facilitate the deactivation of the DMN.

  17. Dopamine Transporters in Striatum Correlated with Deactivation in the Default Mode Network during Visuospatial Attention

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    Tomasi, D.; Fowler, J.; Tomasi, D.; Volkow, N.D.; Wang, R.L.; Telang, F.; Wang, Chang, L.; Ernst, T.; /Fowler, J.S.

    2009-06-01

    Dopamine and dopamine transporters (DAT, which regulate extracellular dopamine in the brain) are implicated in the modulation of attention but their specific roles are not well understood. Here we hypothesized that dopamine modulates attention by facilitation of brain deactivation in the default mode network (DMN). Thus, higher striatal DAT levels, which would result in an enhanced clearance of dopamine and hence weaker dopamine signals, would be associated to lower deactivation in the DMN during an attention task. For this purpose we assessed the relationship between DAT in striatum (measured with positron emission tomography and [{sup 11}C]cocaine used as DAT radiotracer) and brain activation and deactivation during a parametric visual attention task (measured with blood oxygenation level dependent functional magnetic resonance imaging) in healthy controls. We show that DAT availability in caudate and putamen had a negative correlation with deactivation in ventral parietal regions of the DMN (precuneus, BA 7) and a positive correlation with deactivation in a small region in the ventral anterior cingulate gyrus (BA 24/32). With increasing attentional load, DAT in caudate showed a negative correlation with load-related deactivation increases in precuneus. These findings provide evidence that dopamine transporters modulate neural activity in the DMN and anterior cingulate gyrus during visuospatial attention. Our findings suggest that dopamine modulates attention in part by regulating neuronal activity in posterior parietal cortex including precuneus (region involved in alertness) and cingulate gyrus (region deactivated in proportion to emotional interference). These findings suggest that the beneficial effects of stimulant medications (increase dopamine by blocking DAT) in inattention reflect in part their ability to facilitate the deactivation of the DMN.

  18. Hippocampal Sharp-Wave Ripples Influence Selective Activation of the Default Mode Network

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    Kaplan, Raphael; Adhikari, Mohit H.; Hindriks, Rikkert; Mantini, Dante; Murayama, Yusuke; Logothetis, Nikos K.; Deco, Gustavo

    2016-01-01

    Summary The default mode network (DMN) is a commonly observed resting-state network (RSN) that includes medial temporal, parietal, and prefrontal regions involved in episodic memory [1, 2, 3]. The behavioral relevance of endogenous DMN activity remains elusive, despite an emerging literature correlating resting fMRI fluctuations with memory performance [4, 5]—particularly in DMN regions [6, 7, 8]. Mechanistic support for the DMN’s role in memory consolidation might come from investigation of large deflections (sharp-waves) in the hippocampal local field potential that co-occur with high-frequency (>80 Hz) oscillations called ripples—both during sleep [9, 10] and awake deliberative periods [11, 12, 13]. Ripples are ideally suited for memory consolidation [14, 15], since the reactivation of hippocampal place cell ensembles occurs during ripples [16, 17, 18, 19]. Moreover, the number of ripples after learning predicts subsequent memory performance in rodents [20, 21, 22] and humans [23], whereas electrical stimulation of the hippocampus after learning interferes with memory consolidation [24, 25, 26]. A recent study in macaques showed diffuse fMRI neocortical activation and subcortical deactivation specifically after ripples [27]. Yet it is unclear whether ripples and other hippocampal neural events influence endogenous fluctuations in specific RSNs—like the DMN—unitarily. Here, we examine fMRI datasets from anesthetized monkeys with simultaneous hippocampal electrophysiology recordings, where we observe a dramatic increase in the DMN fMRI signal following ripples, but not following other hippocampal electrophysiological events. Crucially, we find increases in ongoing DMN activity after ripples, but not in other RSNs. Our results relate endogenous DMN fluctuations to hippocampal ripples, thereby linking network-level resting fMRI fluctuations with behaviorally relevant circuit-level neural dynamics. PMID:26898464

  19. Longitudinal changes of amygdala and default mode activation in adolescents prenatally exposed to cocaine.

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    Li, Zhihao; Coles, Claire D; Lynch, Mary Ellen; Luo, Yuejia; Hu, Xiaoping

    2016-01-01

    Prenatal cocaine exposure (PCE) is associated with long-term and negative effect on arousal regulation. Recent neuroimaging studies have examined brain mechanisms related to arousal dysregulation with cross-sectional experimental designs; but longitudinal changes in the brain, reflecting group differences in neurodevelopment, have never been directly examined. To directly assess the interaction of PCE and neurodevelopment, the present study used a longitudinal design to analyze functional magnetic resonance imaging (fMRI) data collected from 33 adolescents (21 with PCE and 12 non-exposed controls) while they performed the same working memory task with emotional distracters at two points in time. The mean age of participants was 14.3 years at time_1 and 16.7 years at time_2. With confounding factors statistically controlled, the fMRI data revealed significant exposure-by-time interaction in the activations of the amygdala and default mode network (DMN). For the control adolescents, brain activations associated with emotional arousal (amygdala) and cognitive effort (DMN) were both reduced at time_2 as compared to that at time_1. However, these activation reductions were not observed in the PCE group, indicating persistently high levels of emotional arousal and cognitive effort. In addition, correlations between longitudinal changes in the brain and in behavior have shown that adolescents with persistently high emotional arousal were more likely in need of high cognitive effort; and their cognitive performance was more likely to be affected by distractive challenges. The present results complement and extend previous findings from cross-sectional studies with further evidence supporting the view of PCE associated long-term teratogenic effects on arousal regulation.

  20. Investigating Default Mode and Sensorimotor Network Connectivity in Amyotrophic Lateral Sclerosis.

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    Chenji, Sneha; Jha, Shankar; Lee, Dawon; Brown, Matthew; Seres, Peter; Mah, Dennell; Kalra, Sanjay

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative condition characterized by degeneration of upper motor neurons (UMN) arising from the motor cortex in the brain and lower motor neurons (LMN) in the brainstem and spinal cord. Cerebral changes create differences in brain activity captured by functional magnetic resonance imaging (fMRI), including the spontaneous and simultaneous activity occurring between regions known as the resting state networks (RSNs). Progressive neurodegeneration as observed in ALS may lead to a disruption of RSNs which could provide insights into the disease process. Previous studies have reported conflicting findings of increased, decreased, or unaltered RSN functional connectivity in ALS and do not report the contribution of UMN changes to RSN connectivity. We aimed to bridge this gap by exploring two networks, the default mode network (DMN) and the sensorimotor network (SMN), in 21 ALS patients and 40 age-matched healthy volunteers. An UMN score dichotomized patients into UMN+ and UMN- groups. Subjects underwent resting state fMRI scan on a high field MRI operating at 4.7 tesla. The DMN and SMN changes between subject groups were compared. Correlations between connectivity and clinical measures such as the ALS Functional Rating Scale-Revised (ALSFRS-R), disease progression rate, symptom duration, UMN score and finger tapping were assessed. Significant group differences in resting state networks between patients and controls were absent, as was the dependence on degree of UMN burden. However, DMN connectivity was increased in patients with greater disability and faster progression rate, and SMN connectivity was reduced in those with greater motor impairment. These patterns of association are in line with literature supporting loss of inhibitory interneurons. PMID:27322194