Broensted Acids and Bases: They are not Substances but Molecules or Ions!

For chemistry education we are discussing mainly two concepts of acids and bases: theories of Arrhenius and Broensted. For the first theory, dissociation into ions is generally discussed: acidic solutions contain H+(aq) ions, alkaline solutions contain OH-(aq) ions. This theory therefore deals with substances, which are referred toas acids and bases – it would be even better to take the logical names "acidic and alkaline solutions". If both solutions are mixed in equivalent quantities, the H+(aq) ions react with OH-(aq) ions to form H2O molecules, while the other ions remain in solution (in exceptional cases an insoluble salt may precipitate: sulfuric acid solution reacts with barium chloride solution to solid white barium sulfate and water). The Broensted theory defines proton transfer: a molecule or an ion transfers a proton to another molecule or ion, two conjugated acid-base pairs are involved. Thus, Broensted acids and bases are no more substances, but individual types of particles. Due to the autoionization of H2O molecules (not "autoionization of water"), the following equilibrium exists:H2O + H2O ⇌ H3O+(aq) + OH-(aq)Through this protolysis it is more advantageous to argue rather with H3O+(aq) ions than with H+(aq) ions. In this theory there are still ampholyte particles which react as acid or as base particles depending on the reaction partners: H2O molecules, NH3molecules , HSO4-ions – water, ammonia or sodium hydrogen sulfate cannot be regarded asampholytes. The original publication of Broensted [1] from 1927 makes clear that acids and bases should be molecules or ions, but not substances

Students´ Knowledge about Nanotechnology and the Importance to Introduce Nanotechnology into Chemistry Lessons

The primary objective of this study was to find out what students already know about nanotechnology in order to design a context based module with a nanotechnology background. Therefore a questionnaire was distributed to 116 German students in grade 11. Questions referred to the first thought of the students´ mind when they hear the word nanotechnology, to the size of a nanometer, to if something can be seen at the nanometer scale with the unaided eye, to their self-assessment concerning nanotechnology and to the surface-to-volume ratio of nanoparticles. The findings of the students´ answers were informative and allowed us to design a module in the future that can lead students at school level to understanding nanotechnology

Error-Tolerant Big Data Processing

Real-world data contains various kinds of errors. Before analyzing data, one usually needs to process the raw data. However, traditional data processing based on exactly match often misses lots of valid information. To get high-quality analysis results and fit in the big data era, this thesis studies the error-tolerant big data processing. As most of the data in real world can be represented as a sequence or a set, this thesis utilizes the widely-used sequence-based and set-based similar functions to tolerate errors in data processing and studies the approximate entity extraction, similarity join and similarity search problems. The main contributions of this thesis include: 1. This thesis proposes a unified framework to support approximate entity extraction with both sequence-based and set-based similarity functions simultaneously. The experiments show that the unified framework can improve the state-of-the-art methods by 1 to 2 orders of magnitude. 2. This thesis designs two methods respectively for the sequence and the set similarity joins. For the sequence similarity join, this thesis proposes to evenly partition the sequences to segments. It is guaranteed that two sequences are similar only if one sequence has a subsequence identical to a segment of another sequence. For the set similarity join, this thesis proposes to partition all the sets into segments based on the universe. This thesis further extends the two partition-based methods to support the large-scale data processing framework, Map-Reduce and Spark. The partition-based method won the string similarity join competition held by EDBT and beat the second place by 10 times. 3. This thesis proposes a pivotal prefix filter technique to solve the sequence similarity search problem. This thesis shows that the pivotal prefix filter has stronger pruning power and less filtering cost compared to the state-of-the-art filters.Comment: PhD thesis, Tsinghua University, 201

Correlative Microscopy of Morphology and Luminescence of Cu porphyrin aggregates

Transfer of energy and information through molecule aggregates requires as one important building block anisotropic, cable-like structures. Knowledge on the spatial correlation of luminescence and morphology represents a prerequisite in the understanding of internal processes and will be important for architecting suitable landscapes. In this context we study the morphology, fluorescence and phosphorescence of molecule aggregate structures on surfaces in a spatially correlative way. We consider as two morphologies, lengthy strands and isotropic islands. It turns out that phosphorescence is quite strong compared to fluorescence and the spatial variation of the observed intensities is largely in line with the amount of dye. However in proportion, the strands exhibit more fluorescence than the isotropic islands suggesting weaker non-radiative channels. The ratio fluorescence to phosphorescence appears to be correlated with the degree of aggregation or internal order. The heights at which luminescence saturates is explained in the context of attenuation and emission multireflection, inside the dye. This is supported by correlative photoemission electron microscopy which is more sensitive to the surface region. The lengthy structures exhibit a pronounced polarization dependence of the luminescence with a relative dichroism up to about 60%, revealing substantial perpendicular orientation preference of the molecules with respect to the substrate and parallel with respect to the strands

The effectiveness of parent training as a treatment for preschool attention-deficit/hyperactivity disorder : study protocol for a randomized controlled, multicenter trial of the new Forest Parenting Program in everyday clinical practice

Background: Parent training is recommended as the first-line treatment for attention-deficit/hyperactivity disorder (ADHD) in preschool children. The New Forest Parenting Programme (NFPP) is an evidence-based parenting program developed specifically to target preschool ADHD. Objective: The objective of this trial is to investigate whether the NFPP can be effectively delivered for children referred through official community pathways in everyday clinical practice. Methods: A multicenter randomized controlled parallel arm trial design is employed. There are two treatment arms, NFPP and treatment as usual. NFPP consists of eight individually delivered parenting sessions, where the child attends during three of the sessions. Outcomes are examined at three time points (T1, T2, T3): T1 (baseline), T2 (week 12, post intervention), and T3 (6 month follow/up). 140 children between the ages of 3-7, with a clinical diagnosis of ADHD, informed by the Development and Well Being Assessment, and recruited from three child and adolescent psychiatry departments in Denmark will take part. Randomization is on a 1: 1 basis, stratified for age and gender. Results: The primary endpoint is change in ADHD symptoms as measured by the Preschool ADHD-Rating Scale (ADHD-RS) by T2. Secondary outcome measures include: effects on this measure at T3 and T2 and T3 measures of teacher reported Preschool ADHD-RS scores, parent and teacher rated scores on the Strength & Difficulties Questionnaire, direct observation of ADHD behaviors during Child's Solo Play, observation of parent-child interaction, parent sense of competence, and family stress. Results will be reported using the standards set out in the Consolidated Standards of Reporting Trials Statement for Randomized Controlled Trials of nonpharmacological treatments. Conclusions: The trial will provide evidence as to whether NFPP is a more effective treatment for preschool ADHD than the treatment usually offered in everyday clinical practice

The effectiveness of parent training as a treatment for preschool Attention-Deficit/Hyperactivity Disorder: study protocol for a randomized controlled, multicenter trial of the New Forest Parenting Program in everyday clinical practice

Background: Parent training is recommended as the first-line treatment for attention-deficit/hyperactivity disorder (ADHD) in preschool children. The New Forest Parenting Programme (NFPP) is an evidence-based parenting program developed specifically to target preschool ADHD.Objective: The objective of this trial is to investigate whether the NFPP can be effectively delivered for children referred through official community pathways in everyday clinical practice.Methods: A multicenter randomized controlled parallel arm trial design is employed. There are two treatment arms, NFPP and treatment as usual. NFPP consists of eight individually delivered parenting sessions, where the child attends during three of the sessions. Outcomes are examined at three time points (T1, T2, T3): T1 (baseline), T2 (week 12, post intervention), and T3 (6 month follow/up). 140 children between the ages of 3-7, with a clinical diagnosis of ADHD, informed by the Development and Well Being Assessment, and recruited from three child and adolescent psychiatry departments in Denmark will take part. Randomization is on a 1:1 basis, stratified for age and gender.Results: The primary endpoint is change in ADHD symptoms as measured by the Preschool ADHD-Rating Scale (ADHD-RS) by T2. Secondary outcome measures include: effects on this measure at T3 and T2 and T3 measures of teacher reported Preschool ADHD-RS scores, parent and teacher rated scores on the Strength & Difficulties Questionnaire, direct observation of ADHD behaviors during Child’s Solo Play, observation of parent-child interaction, parent sense of competence, and family stress. Results will be reported using the standards set out in the Consolidated Standards of Reporting Trials Statement for Randomized Controlled Trials of nonpharmacological treatments.Conclusions: The trial will provide evidence as to whether NFPP is a more effective treatment for preschool ADHD than the treatment usually offered in everyday clinical practice.Trial Registration: ClinicalTrials.gov NCT01684644; https://clinicaltrials.gov/ct2/show/NCT01684644?term= NCT01684644&rank=

Correlations and Fluctuations in High-Energy Nuclear Collisions

Nucleon correlations in the target and projectile nuclei are shown to reduce significantly the fluctuations in multiple nucleon-nucleon collisions, total multiplicity and transverse energy in relativistic heavy-ion collisions, in particular for heavy projectile and target. The interplay between cross-section fluctuations, from color transparency and opacity, and nuclear correlations is calculated and found to be able to account for large fluctuations in transverse energy spectra. Numerical implementation of correlations and cross-section fluctuations in Monte-Carlo codes is discussed.Comment: 30 pages, in Revtex, plus 4 figures. Figures and preprint can be obtained by mailing address to: [email protected]