Classification with Margin Constraints: A Unification with Applications to Optimization

This paper introduces Classification with Margin Constraints (CMC), a simple generalization of cost-sensitive classification that unifies several learning settings. In particular, we show that a CMC classifier can be used, out of the box, to solve regression, quantile estimation, and several anomaly detection formulations. On the one hand, our reductions to CMC are at the loss level: the optimization problem to solve under the equivalent CMC setting is exactly the same as the optimization problem under the original (e.g. regression) setting. On the other hand, due to the close relationship between CMC and standard binary classification, the ideas proposed for efficient optimization in binary classification naturally extend to CMC. As such, any improvement in CMC optimization immediately transfers to the domains reduced to CMC, without the need for new derivations or programs. To our knowledge, this unified view has been overlooked by the existing practice in the literature, where an optimization technique (such as SMO or PEGASOS) is first developed for binary classification and then extended to other problem domains on a case-by-case basis. We demonstrate the flexibility of CMC by reducing two recent anomaly detection and quantile learning methods to CMC

Bostonia: The Boston University Alumni Magazine. Volume 33

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Polyaromatic Hydrocarbons with an Imperfect Aromatic System as Catalysts of Interstellar H2_{2} Formation

Although H$_{2}$ is the simplest and the most abundant molecule in the Universe, its formation in the interstellar medium, especially in the photodissociation regions is far from being fully understood. According to suggestions, the formation of H$_{2}$ is catalyzed by polyaromatic hydrocarbons (PAHs) on the surface of interstellar grains. In the present study, we have investigated the catalytic effect of small PAHs with an imperfect aromatic system. Quantum chemical computations were performed for the H-atom-abstraction and H-atom-addition reactions of benzene, cyclopentadiene, cycloheptatriene, indene, and 1H-phenalene. Heights of reaction barriers and tunneling reaction rate constants were computed with density functional theory using the MPWB1K functional. For each molecule, the reaction path and the \warn{rate constants} were determined at 50 K using ring-polymer instanton theory, and the temperature dependence of the \warn{rate constants} was investigated for cyclopentadiene and cycloheptatriene. The computational results reveal that defects in the aromatic system compared to benzene can increase the rate of the catalytic H$_{2}$ formation at 50 K

Integration of microRNA changes in vivo identifies novel molecular features of muscle insulin resistance in type 2 diabetes

Skeletal muscle insulin resistance (IR) is considered a critical component of type II diabetes, yet to date IR has evaded characterization at the global gene expression level in humans. MicroRNAs (miRNAs) are considered fine-scale rheostats of protein-coding gene product abundance. The relative importance and mode of action of miRNAs in human complex diseases remains to be fully elucidated. We produce a global map of coding and non-coding RNAs in human muscle IR with the aim of identifying novel disease biomarkers. We profiled >47,000 mRNA sequences and >500 human miRNAs using gene-chips and 118 subjects (n = 71 patients versus n = 47 controls). A tissue-specific gene-ranking system was developed to stratify thousands of miRNA target-genes, removing false positives, yielding a weighted inhibitor score, which integrated the net impact of both up- and down-regulated miRNAs. Both informatic and protein detection validation was used to verify the predictions of in vivo changes. The muscle mRNA transcriptome is invariant with respect to insulin or glucose homeostasis. In contrast, a third of miRNAs detected in muscle were altered in disease (n = 62), many changing prior to the onset of clinical diabetes. The novel ranking metric identified six canonical pathways with proven links to metabolic disease while the control data demonstrated no enrichment. The Benjamini-Hochberg adjusted Gene Ontology profile of the highest ranked targets was metabolic (P < 7.4 × 10-8), post-translational modification (P < 9.7 × 10-5) and developmental (P < 1.3 × 10-6) processes. Protein profiling of six development-related genes validated the predictions. Brain-derived neurotrophic factor protein was detectable only in muscle satellite cells and was increased in diabetes patients compared with controls, consistent with the observation that global miRNA changes were opposite from those found during myogenic differentiation. We provide evidence that IR in humans may be related to coordinated changes in multiple microRNAs, which act to target relevant signaling pathways. It would appear that miRNAs can produce marked changes in target protein abundance in vivo by working in a combinatorial manner. Thus, miRNA detection represents a new molecular biomarker strategy for insulin resistance, where micrograms of patient material is needed to monitor efficacy during drug or life-style interventions

Kinetics and thermochemistry of the reaction of 3-methylpropargyl radical with molecular oxygen

We have measured the kinetics and thermochemistry of the reaction of 3-methylpropargyl radical (but-2-yn-1-yl) with molecular oxygen over temperature (223-681 K) and bath gas density (1.2 - 15.0 x 10(16)cm(-3)) ranges employing photoionization mass-spectrometry. At low temperatures (223-304 K), the reaction proceeds overwhelmingly by a simple addition reaction to the -CH2 end of the radical, and the measured CH3CCCH2 center dot+O-2 reaction rate coefficient shows negative temperature dependence and depends on bath gas density. At intermediate temperatures (340-395 K), the addition reaction equilibrates and the equilibrium constant was determined at different temperatures. At high temperatures (465-681 K), the kinetics is governed by O-2 addition to the third carbon atom of the radical, and rate coefficient measurements were again possible. The high temperature CH3CCCH2 center dot +O(2 )rate coefficient is much smaller than at low T, shows positive temperature dependence, and is independent of bath gas density. In the intermediate and high temperature ranges, we observe a formation signal for ketene (ethenone). The reaction was further investigated by combining the experimental results with quantum chemical calculations and master equation modeling. By making small adjustments (2 - 3 kJ mol(-1)) to the energies of two key transition states, the model reproduces the experimental results within uncertainties. The experimentally constrained master equation model was used to simulate the CH3CCCH2 center dot+ O-2 reaction system at temperatures and pressures relevant to combustion. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.Peer reviewe

Kinetics and thermochemistry of the reaction of 1-methylpropargyl radicals with oxygen molecules : Experiments and computations

We have used laser-photolysis/photoionization mass spectrometry to measure the kinetics of the reaction of 1-methylpropargyl (but-3-yn-2-yl, CH C=CH-CH3) radicals with oxygen molecules as a function of temperature (T = 200 - 685 K) and bath gas density (1.2 - 15 x 10(16) cm(-3)). The low temperature (TPeer reviewe

An idiographic approach to Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF) Part II. Ecological momentary assessment of three individuals with severe IEI-EMF

IEI-EMF refers to a self-reported sensitivity characterized by attribution of non-specific physical symptoms to exposure to weak EMFs. The majority of empirical results do not support the existence of a causal relationship between EMF and IEI-EMF. However, this conclusion was drawn from environmental and experimental studies that are not without methodological limitations. In the current study, as part of a complex biopsychosocial approach, an ecological momentary assessment (EMA) protocol was applied for the investigation of the temporal relationship between actual radio frequency (RF) EMF exposure and IEI-EMF, at the individual level. Continuous measurement of autonomic variables by holter electrocardiogram (ECG) monitors and the ambient RF EMF by personal dosimeters, as well as repeated (8/day) paper-and-pencil assessments of momentary internal states (symptoms, mood, perceived EMF intensity) and situational factors was conducted for 21 days with the participation of three individuals with severe IEI-EMF. Temporal relationships were examined by time series analyses. For two participants, the results did not support the association between the suspected EMF frequency range(s) and symptom reports. Nevertheless, the results revealed a reverse association with respect to another frequency range (GSM900 downlink), which contradicts the IEI-EMF condition. Autonomic activation related findings were inconsistent. For the third participant, the claimed association was partly supported, both for symptom reports and autonomic reactions (UMTS downlink, total RF; RMS values). The findings of this study suggest that IEI-EMF does not have a unitary aetiology. For certain individuals, a biophysical background cannot be excluded, whereas no such underlying factor appears to be at work for others. EMA is a useful method for the investigation of the aetiology of IEI-EMF

Rare occult macular dystrophy with a pathogenic variant in the RP1L1 gene in a patient of Swiss descent

Purpose: We report a first case of bilateral occult macular dystrophy (OMD) with a c.133C>T (p.Arg45Trp) pathogenic variant in the retinitis pigmentosa 1-like 1 (RP1L1) gene in a patient of Caucasian Swiss decent. Observations: A 34-year-old man presented with decreased visual acuity known since childhood. Fundus examination of both eyes revealed no pathology other than mildly increased granularity of the foveal retinal pigment epithelium. The full-field electroretinogram (ffERG) presented with normal findings while the multifocal electroretinogram (mfERG) showed severely reduced amplitudes of the foveal response. Optical coherence tomography (OCT) showed foveal outer retinal atrophy. Fundus autofluorescence (FAF) imaging demonstrated near-normal findings with minimal mottling at the posterior pole. The genetic analysis revealed a heterozygous pathogenic variant (c.133C>T, p.Arg45Trp) in the RP1L1 gene. Conclusion and importance: Our present case suggests that OMD shows a wide range of clinical presentations with a variety of ophthalmological findings, age of disease onset, visual acuity, and genetic diversity

An experimental and computational study of the reaction between pent-3-en-2-yl radicals and oxygen molecules : switching from pure stabilisation to pure decomposition with increasing temperature

We have used laser-photolysis-photoionization mass spectrometry, quantum chemical calculations, and master equation simulations to investigate the kinetics of the reaction between (E/Z)-pent-3-en-2-yl (CH3-CH - CH - CH-CH3), a resonance-stabilised hydrocarbon radical, and molecular oxygen. The time-resolved experiments were performed over a wide temperature range (240-750 K) at relatively low pressures (0.4-7 Torr) under pseudo-first-order conditions (excess [O-2]). Helium bath gas was used in most experiments, but nitrogen was employed in a few measurements to investigate the effect of a heavier collider on the kinetics of the studied reaction. The experimental traces were directly used to optimise parameters in the master equation model using the recently implemented trace fitting feature in the MESMER program. At low temperatures (T < 300 K), the reaction proceeds by barrierless recombination reactions to form peroxyl adducts, and the radical traces are single-exponential. Between 326 K and 376 K, equilibration between the reactants and the peroxyl adducts is observed, and the radical traces are multi-exponential. Interestingly, at temperatures above 500 K, single-exponential decays were again observed, although the reaction is much slower than at low temperatures. The master equation simulations revealed that at both low and high temperatures, the radical decay rate is governed by a single eigenvalue. At low temperatures, this eigenvalue corresponds to recombination reactions, and at high temperatures to the phenomenological formation of bimolecular products. Between low and high temperatures (the exact temperature thresholds depend on [O-2]), there is a region of avoided crossing in which the rate coefficient "jumps" from one eigencurve to the other. Although chemically significant eigenvalues are not well separated from internal energy relaxation eigenvalues at elevated temperatures (600 K at 0.01 bar, 850 K at 100 bar), we observed that many of the Bartis-Widom rate coefficients produced by the master equation model were valid up to 1500 K. Our simulations predict that the most important reaction channel at high temperatures is the formation of (E/Z)-penta-1,3-diene and hydroperoxyl. The experimentally constrained master equation model was used to simulate the title reaction over a wide range of conditions. To facilitate the use of our results in autoignition and combustion models, modified Arrhenius representations are given for the most important reaction channels.Peer reviewe