28 research outputs found
Anderson localization as a parametric instability of the linear kicked oscillator
We rigorously analyse the correspondence between the one-dimensional standard
Anderson model and a related classical system, the `kicked oscillator' with
noisy frequency. We show that the Anderson localization corresponds to a
parametric instability of the oscillator, with the localization length
determined by an increment of the exponential growth of the energy. Analytical
expression for a weak disorder is obtained, which is valid both inside the
energy band and at the band edge.Comment: 7 pages, Revtex, no figures, submitted to Phys. Rev.
1D quantum models with correlated disorder vs. classical oscillators with coloured noise
We perform an analytical study of the correspondence between a classical
oscillator with frequency perturbed by a coloured noise and the one-dimensional
Anderson-type model with correlated diagonal disorder. It is rigorously shown
that localisation of electronic states in the quantum model corresponds to
exponential divergence of nearby trajectories of the classical random
oscillator. We discuss the relation between the localisation length for the
quantum model and the rate of energy growth for the stochastic oscillator.
Finally, we examine the problem of electron transmission through a finite
disordered barrier by considering the evolution of the classical oscillator.Comment: 23 pages, LaTeX fil
Viruses as sole causative agents of severe acute respiratory tract infections in children
Background: Respiratory syncytial virus (RSV) and influenza A viruses are known to cause severe acute respiratory tract infections (SARIs) in children. For other viruses like human rhinoviruses (HRVs) this is less well established. Viral or bacterial co-infections are often considered essential for severe manifestations of these virus infections. Objective: The study aims at identifying viruses that may cause SARI in children in the absence of viral and bacterial co-infections, at identifying disease characteristics associated with these single virus infections, and at identifying a possible correlation between viral loads and disease severities. Study Design: Between April 2007 and March 2012, we identified children (<18 year) with or without a medical history, admitted to our paediatric intensive care unit (PICU) with SARI or to the medium care (MC) with an acute respiratory tract infection (ARTI) (controls). Data were extracted from the clinical and laboratory databases of our tertiary care paediatric hospital. Patient specimens were tested for fifteen respiratory viruses with real-time reverse transcriptase PCR assays and we selected patients with a single virus infection only. Typical bacterial co-infections were considered unlikely to have contributed to the PICU or MC admission based on C-reactive protein-levels or bacteriological test results if performed. Results: We identified 44 patients admitted to PICU with SARI and 40 patients admitted to MC with ARTI. Twelve viruses were associated with SARI, ten of which were also associated with ARTI in the absence of typical bacterial and viral co-infections, with RSV and HRV being the most frequent causes. Viral loads were not different between PICU-SARI patients and MCARTI patients. Conclusion: B
PENGGUNAAN METODE INKUIRI DALAM PENINGKATAN HASIL BELAJAR MATEMATIKA DI KELAS V SEKOLAH DASAR
Dwi Ari Istianto1, Triyono2, Kartika Chrysti Suryandari3 PGSD FKIP Universitas Negeri Sebelas Maret, Jl. Kepodang 67A Panjer Kebumen Email [email protected] Mahasiswa PGSD FKIP UNSDosen PGSD FKIP UNS Abstract: Using Inquiry Methods in Increasing Result of Mathematic Study in five grade of Elementary School. The purpose of this research were (1) to describe steps of inquiry method in increasing result of mathematic study in five grade of Elementary School, (2) identify constraints and solutions using inquiry methods in increasing result of mathematic study in five grade of state elementary school. This study is classroom action research (CAR) conducted in three cycles, each cycle includes the planning, implementation, observation and reflection. The data were analysis using Miles and Huberman interactive model consist of three components are: data reduction, data display, and conclusion drawing/verification. The results showed that (1) the steps of inquiry method can be run apropriate to the scenario, (2) using inquiry method can increasing result of mathematic study in five grade of Elementary School. Increasing result of mathematic study from pre-test were 40%, in the first cycle were 60%, in the second cycle were 73% and the third cycle increase until 80%. Key words: result of study, mathematic, inquiry method Abstrak: Penggunaan Metode Inkuiri dalam Peningkatan Hasil Belajar Matematika di Kelas V Sekolah Dasar. Penelitian ini bertujuan untuk mendeskripsikan (1) mendiskripsikan langkah-langkah metode inkuiri dalam peningkatan hasil belajar Matematika kelas V sekolah dasar, (2) mengidentifikasi kendala dan solusi dalam penggunaan langkah-langkah metode Inkuiri kelas V sekolah dasar. Penelitian ini adalah penelitian tindakan kelas yang dilaksanakan dalam tiga siklus, masing-masing siklus mencakup tahap perencanaan, pelaksanaan, observasi dan refleksi. Teknik analisis data menggunakan teknik interaktif model Miles dan Huberman yang terdiri dari tiga komponen analisis yaitu reduksi data, sajian data dan penarikan kesimpulan dan verifikasi. Hasilnya menunjukkan bahwa: (1) penggunaan langkah-langkah metode Inkuiri dapat berjalan sesuai skenario, (2) penggunaan metode inkuiri dapat meningkatkan hasil belajar matematika siswa kelas V sekolah dasar. Peningkatan hasil belajar matematika dari pratindakan mencapai 40%, di siklus I 60%, di siklus II 73% dan siklus III meningkat menjadi 80%. Kata Kunci: metode Inkuiri, hasil belajar matematik
Prevalence and Characteristics of Asthma-COPD Overlap in Routine Primary Care Practices
Rationale: Adults may exhibit characteristics of both asthma and chronic obstructive pulmonary disease (COPD), a situation recently described as asthma-COPD overlap (ACO). There is a paucity of information about ACO in primary care. Objectives: To estimate the prevalence and describe characteristics of individuals withACOin primary care practices among patients currently diagnosed with asthma, COPD, or both; and to compare the prevalence and characteristics of ACO among the three source populations. Methods: The Respiratory Effectiveness Group conducted a crosssectional study of individuals ≥40 years old and with ≥2 outpatient primary care visits over a 2-year period in theUKOptimum Patient Care Research Database. Patients were classified into one of three source populations based on diagnostic codes: 1) COPD only, 2) both asthma and COPD, or 3) asthma only.ACOwas defined as the presence of all of the following 1) age ≥40 years, 2) current or former smoking, 3) postbronchodilator airflow limitation (forced expiratory volume in 1 second/ forced vital capacity <0.7), and 4) ≥12% and ≥200 ml reversibility in post-bronchodilator forced expiratory volume in 1 second. Results: Among 2,165 individuals (1,015 COPD only, 395 with both asthma and COPD, and 755 asthma only), the overall prevalence of ACO was 20% (95% confidence interval, 18-23%). Patients with ACO had a mean age of 70 years (standard deviation, 11 yr), 60% were men, 73% were former smokers (the rest were current smokers), and 66% were overweight or obese. Comorbid conditions were common in patients with ACO, including diabetes (53%), cardiovascular disease (36%), hypertension (30%), eczema (23%), and rhinitis (21%). The prevalence of ACO was higher in patients with a diagnosis of both asthma and COPD (32%) compared with a diagnosis of COPD only (20%; P<0.001) or asthma only (14%; P<0.001). Demographic and clinical characteristics of ACO varied across these three source populations. Conclusions: One in five individuals with a diagnosis of COPD, asthma, or both asthma and COPD in primary care settings have ACO based on the Respiratory Effectiveness Group ACO Working group criteria. The prevalence and characteristics of patients with ACO varies across the three source populations
Treatment-specific risk of subsequent malignant neoplasms in five-year survivors of diffuse large B-cell lymphoma
Background: The introduction of rituximab significantly improved the prognosis of diffuse large B-cell lymphoma (DLBCL), emphasizing the importance of evaluating the long-term consequences of exposure to radiotherapy, alkylating agents and anthracycline-containing (immuno)chemotherapy among DLBCL survivors. Methods: Long-term risk of subsequent malignant neoplasms (SMNs) was examined in a multicenter cohort comprising 2373 5-year DLBCL survivors treated at ages 15-61 years in 1989-2012. Observed SMN numbers were compared with expected cancer incidence to estimate standardized incidence ratios (SIRs) and absolute excess risks (AERs/10 000 person-years). Treatment-specific risks were assessed using multivariable Cox regression. Results: After a median follow-up of 13.8 years, 321 survivors developed one or more SMNs (SIR 1.5, 95% CI 1.3-1.8, AER 51.8). SIRs remained increased for at least 20 years after first-line treatment (SIR ≥20-year follow-up 1.5, 95% CI 1.0-2.2, AER 81.8) and were highest among patients ≤40 years at first DLBCL treatment (SIR 2.7, 95% CI 2.0-3.5). Lung (SIR 2.0, 95% CI 1.5-2.7, AER 13.4) and gastrointestinal cancers (SIR 1.5, 95% CI 1.2-2.0, AER 11.8) accounted for the largest excess risks. Treatment with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin versus ≤2250 mg/m2/≤150 mg/m2, respectively, was associated with increased solid SMN risk (hazard ratio 1.5, 95% CI 1.0-2.2). Survivors who received rituximab had a lower risk of subdiaphragmatic solid SMNs (hazard ratio 0.5, 95% CI 0.3-1.0) compared with survivors who did not receive rituximab. Conclusion: Five-year DLBCL survivors have an increased risk of SMNs. Risks were higher for survivors ≤40 years at first treatment and survivors treated with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin, and may be lower for survivors treated in the rituximab era, emphasizing the need for studies with longer follow-up for rituximab-treated patients.</p
Treatment-specific risk of subsequent malignant neoplasms in five-year survivors of diffuse large B-cell lymphoma
Background: The introduction of rituximab significantly improved the prognosis of diffuse large B-cell lymphoma (DLBCL), emphasizing the importance of evaluating the long-term consequences of exposure to radiotherapy, alkylating agents and anthracycline-containing (immuno)chemotherapy among DLBCL survivors. Methods: Long-term risk of subsequent malignant neoplasms (SMNs) was examined in a multicenter cohort comprising 2373 5-year DLBCL survivors treated at ages 15-61 years in 1989-2012. Observed SMN numbers were compared with expected cancer incidence to estimate standardized incidence ratios (SIRs) and absolute excess risks (AERs/10 000 person-years). Treatment-specific risks were assessed using multivariable Cox regression. Results: After a median follow-up of 13.8 years, 321 survivors developed one or more SMNs (SIR 1.5, 95% CI 1.3-1.8, AER 51.8). SIRs remained increased for at least 20 years after first-line treatment (SIR ≥20-year follow-up 1.5, 95% CI 1.0-2.2, AER 81.8) and were highest among patients ≤40 years at first DLBCL treatment (SIR 2.7, 95% CI 2.0-3.5). Lung (SIR 2.0, 95% CI 1.5-2.7, AER 13.4) and gastrointestinal cancers (SIR 1.5, 95% CI 1.2-2.0, AER 11.8) accounted for the largest excess risks. Treatment with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin versus ≤2250 mg/m2/≤150 mg/m2, respectively, was associated with increased solid SMN risk (hazard ratio 1.5, 95% CI 1.0-2.2). Survivors who received rituximab had a lower risk of subdiaphragmatic solid SMNs (hazard ratio 0.5, 95% CI 0.3-1.0) compared with survivors who did not receive rituximab. Conclusion: Five-year DLBCL survivors have an increased risk of SMNs. Risks were higher for survivors ≤40 years at first treatment and survivors treated with >4500 mg/m2 cyclophosphamide/>300 mg/m2 doxorubicin, and may be lower for survivors treated in the rituximab era, emphasizing the need for studies with longer follow-up for rituximab-treated patients.</p
Clinical characteristics of women captured by extending the definition of severe postpartum haemorrhage with 'refractoriness to treatment': a cohort study
Background: The absence of a uniform and clinically relevant definition of severe postpartum haemorrhage
hampers comparative studies and optimization of clinical management. The concept of persistent postpartum
haemorrhage, based on refractoriness to initial first-line treatment, was proposed as an alternative to common
definitions that are either based on estimations of blood loss or transfused units of packed red blood cells
(RBC). We compared characteristics and outcomes of women with severe postpartum haemorrhage captured
by these three types of definitions.
Methods: In this large retrospective cohort study in 61 hospitals in the Netherlands we included 1391 consecutive
women with postpartum haemorrhage who received either ≥4 units of RBC or a multicomponent transfusion. Clinical
characteristics and outcomes of women with severe postpartum haemorrhage defined as persistent postpartum
haemorrhage were compared to definitions based on estimated blood loss or transfused units of RBC within 24 h
following birth. Adverse maternal outcome was a composite of maternal mortality, hysterectomy, arterial embolisation
and intensive care unit admission.
Results: One thousand two hundred sixty out of 1391 women (90.6%) with postpartum haemorrhage fulfilled the
definition of persistent postpartum haemorrhage. The majority, 820/1260 (65.1%), fulfilled this definition within 1 h
following birth, compared to 819/1391 (58.7%) applying the definition of ≥1 L blood loss and 37/845 (4.4%) applying
the definition of ≥4 units of RBC. The definition persistent postpartum haemorrhage captured 430/471 adverse maternal
outcomes (91.3%), compared to 471/471 (100%) for ≥1 L blood loss and 383/471 (81.3%) for ≥4 units of RBC. Persistent
postpartum haemorrhage did not capture all adverse outcomes because of missing data on timing of initial, first-line
treatment.
Conclusion: The definition persistent postpartum haemo
Principles and practice of lipidomics
The technical advances in mass spectrometry, particularly the development of (ultra)-high-resolution/mass accuracy measurement capabilities in combination with refinement of soft ionization techniques, have increased the application and success of lipidomics to answer biological questions in relation to lipid metabolism. Together with other omics technologies, lipidomics has become an important tool to practice systems biology as lipids comprise a very significant part of the metabolome and play pleiotropic roles in cellular functions. As an increasing number of disorders are linked to lipid metabolism, lipidomics is used to search for biomarkers, understand disease mechanism and follow the efficacy of therapeutic options. This review provides a first introduction to the major methodological strategies currently used for mass spectrometry-based lipidomics and associated data pre-processing and analysis
Lipidomic analysis of fibroblasts from Zellweger spectrum disorder patients identifies disease-specific phospholipid ratios
Peroxisomes are subcellular organelles involved in various metabolic processes, including fatty acid and phospholipid homeostasis. The Zellweger spectrum disorders (ZSDs) represent a group of diseases caused by a defect in the biogenesis of peroxisomes. Accordingly, cells from ZSD patients are expected to have an altered composition of fatty acids and phospholipids. Using an LC/MS-based lipidomics approach, we show that the phospholipid composition is characteristically altered in cultured primary skin fibroblasts from ZSD patients when compared with healthy controls. We observed a marked overall increase of phospholipid species containing very long-chain fatty acids, and a decrease of phospholipid species with shorter fatty acid species in ZSD patient fibroblasts. In addition, we detected a distinct phosphatidylcholine profile in ZSD patients with a severe and mild phenotype when compared with control cells. Based on our data, we present a set of specific phospholipid ratios for fibroblasts that clearly discriminate between mild and severe ZSD patients, and those from healthy controls. Our findings will aid in the diagnosis and prognosis of ZSD patients, including an increasing number of mild patients in whom hardly any abnormalities are observed in biochemical parameters commonly used for diagnosis