Frequency of Change Orders in Highway Construction Using Alternate Count-Data Modeling Methods

A common problem at state transportation agencies is the inability to complete projects within the original scope of work. Change orders, which are contractual documents issued to accommodate the additional work in a contract, are generally due to root causes such as design errors, unexpected site conditions, and weather conditions, and intermediate causes such as bidding characteristics. At the preaward phase of project management, an improved understanding of the factors that are associated with change orders will be of value and also can serve as a basis for taking steps to reduce concomitant contractual aberrations such as time delay and cost overruns. Recognizing that the occurrence of change orders is a count variable, this paper analyzes the frequency of change orders using a variety of count-modeling methods including the negative binomial, Poisson, zero-inflated negative binomial, and zero-inflated Poisson. Using 5 years of contract data from Indiana highway projects, appropriate models are estimated to assess the influence of project type, contract type, project duration, and project cost on the frequency of change orders.     

Fully Enzymatic Resolution of Chiral Amines: Acylation and Deacylation in the Presence of Candida antarctica Lipase B

A fully enzymatic methodology for the resolution of chiral amines has been demonstrated. Candida antarctica lipase B (CaLB)‐catalyzed acylation with N‐methyl‐ and N‐phenylglycine, as well as analogues having the general formula R¹ X CH₂CO₂R² (R¹=Me, Ph; X=O, S) afforded the corresponding enantioenriched amides, which were subsequently enzymatically hydrolyzed. Surprisingly, CaLB also proved to be the catalyst of choice for this latter step. The heteroatom in the acyl donor profoundly influences both the enzymatic acylation and deacylation; the O‐substituted reagents performed best with regard to enantioselectivity as well as reaction rate in synthesis and hydrolysis.     

Weakly supervised learning of a classifier for unusual event detection

In this paper, we present an automatic classification framework combining appearance based features and hidden Markov models (HMM) to detect unusual events in image sequences. One characteristic of the classification task is that anomalies are rare. This reflects the situation in the quality control of industrial processes, where error events are scarce by nature. As an additional restriction, class labels are only available for the complete image sequence, since frame-wise manual scanning of the recorded sequences for anomalies is too expensive and should, therefore, be avoided. The proposed framework reduces the feature space dimension of the image sequences by employing subspace methods and encodes characteristic temporal dynamics using continuous hidden Markov models (CHMMs). The applied learning procedure is as follows. 1) A generative model for the regular sequences is trained (one-class learning). 2) The regular sequence model (RSM) is used to locate potentially unusual segments within error sequences by means of a change detection algorithm (outlier detection). 3) Unusual segments are used to expand the RSM to an error sequence model (ESM). The complexity of the ESM is controlled by means of the Bayesian Information Criterion (BIC). The likelihood ratio of the data given the ESM and the RSM is used for the classification decision. This ratio is close to one for sequences without error events and increases for sequences containing error events. Experimental results are presented for image sequences recorded from industrial laser welding processes. We demonstrate that the learning procedure can significantly reduce the user interaction and that sequences with error events can be found with a small false positive rate. It has also been shown that a modeling of the temporal dynamics is necessary to reach these low error rates.     

Protein kinase Mzeta maintains fear memory in the amygdala but not in the hippocampus.

Recent work on the long-term stability of memory and synaptic plasticity has identified a potentially critical role for protein kinase Mzeta (PKMζ). PKMζ is a constitutively active, atypical isoform of protein kinase C that is believed to maintain long term potentiation at hippocampal synapses in vitro. In behaving animals, local inhibition of PKMζ disrupts spatial memory in the hippocampus and conditioned taste aversion memory in the insular cortex. The role of PKMζ in context fear memory is less clear. This study examined the role of PKMζ in amygdala and hippocampal neurons following a standard fear conditioning protocol. The results indicate that PKMζ inhibition in the amygdala, but not in the hippocampus, can disrupt fear memory. This suggests that PKMζ may only maintain select forms of memory in specific brain structures and does not participate in a universal memory storage mechanism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationships between Mitochondrial Function,AMPK, and TORC1 Signaling in Lymphoblasts with Premutation Alleles of the FMR1 Gene

The X-linked FMR1 gene contains a non-coding trinucleotide repeat in its 5’ region that, in normal, healthy individuals contains 20–44 copies. Large expansions of this region (>200 copies) cause fragile X syndrome (FXS), but expansions of 55–199 copies (referred to as premutation alleles) predispose carriers to a neurodegenerative disease called fragile X-associated tremor/ataxia syndrome (FXTAS). The cytopathological mechanisms underlying FXTAS are poorly understood, but abnormalities in mitochondrial function are believed to play a role. We previously reported that lymphoblastoid cell lines (LCLs, or lymphoblasts) of premutation carriers have elevated mitochondrial respiratory activities. In the carriers, especially those not clinically affected with FXTAS, AMP-activated protein kinase (AMPK) activity was shown to be elevated. In the FXTAS patients, however, it was negatively correlated with brain white matter lesions, suggesting a protective role in the molecular mechanisms. Here, we report an enlarged and extended study of mitochondrial function and associated cellular stress-signaling pathways in lymphoblasts isolated from male and female premutation carriers, regardless of their clinical status, and healthy controls. The results confirmed the elevation of AMPK and mitochondrial respiratory activities and reduction in reactive O₂ species (ROS) levels in premutation cells and revealed for the first time that target of rapamycin complex I (TORC1) activities are reduced. Extensive correlation, multiple regression, and principal components analysis revealed the best fitting statistical explanations of these changes in terms of the other variables measured. These suggested which variables might be the most “proximal” regulators of the others in the extensive network of known causal interactions amongst the measured parameters of mitochondrial function and cellular stress signaling. In the resulting model, the premutation alleles activate AMPK and inhibit both TORC1 and ROS production, the reduced TORC1 activity contributes to activation of AMPK and of nonmitochondrial metabolism, and the higher AMPK activity results in elevated catabolic metabolism, mitochondrial respiration, and ATP steady state levels. In addition, the results suggest a separate CGG repeat number-dependent elevation of TORC1 activity that is insufficient to overcome the inhibition of TORC1 in premutation cells but may presage the previously reported activation of TORC1 in FXS cells.     

The incremental validity of vocational self-efficacy: An examination of interest, self-efficacy, and occupation.

The authors examined the incremental validity, beyond vocational interest, of the General Confidence Themes of the Skills Confidence Inventory (N. E. Betz, F. H. Borgen, & L. W. Harmon, 1996a) as measures of vocational self-efficacy in identifying tenured and satisfied membership in 21 occupational groups for 1,105 employed women and men. The General Occupational Themes of the Strong Interest Inventory (L. W. Harmon, J. C. Hansen, F. H. Borgen, & A. L. Hammer, 1994) were used to measure interest. The results replicated T. J. G. Tracey's (1997) finding that self-efficacy and interest form similar structures. Results also demonstrated the explanatory power of self-efficacy and interest and the incremental validity of self-efficacy. The authors suggest that the Skills Confidence Inventory is (a) a valid measure of tenured and satisfied occupational membership, (b) a distinct measure from interest but similar in structure, and (c) a potentially useful career assessment measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of the 40 mg Swelling Test for Measuring Starch Functionality

This paper presents a small‐scale test for measuring starch quality and demonstrates its ability to predict end‐product quality. This 40 mg swelling test measures the swelling power of gelatinised starch by determining the mass of the final product after a defined gelatinisation process. It is compared with the larger scale swelling power and swelling volume tests and with other starch gel analyses methods (differential scanning calorimetry, hot stage microscopy and Rapid Visco Analyser). Suitability of the 40 mg swelling test as a small‐scale early generation breeding test for measuring starch quality is evaluated. This new method is also evaluated as being suitable to provide an indication of the end‐product quality of Japanese white salted noodles.     

Photoreflectance study of electric field distributions in semiconductors heterostructures grown on semi-insulating substrates

We have studied the photoref lectance (PR) spectra from a MBE grown heterostructure consisting of 200 nm of Ga_0.83Al_0.17As, a 800 nm GaAs buffer layer on a semi-insulating (100) LEC GaAs substrate. By varying both the pump beam wavelength and modulation frequency (up to 100 kHz) we are able to identify the component layers, their quality and the properties of the various interfaces. In this study we find evidence for a low density of interface states between the GaAs buffer layer and GaAlAs layer and a relatively large density of interface states between the substrate and buffer regions. These states, previously observed by Deep Level Transient Spectroscopy of doped structures, are presumably associated with the interface produced by MBE growth on etched and air exposed substrates. However, in our material, since the substrate is semi-insulating and the buffer layer is undoped, it is difficult to resolve these states spatially by C-V techniques. Our results show that the PR technique can be used to characterize low conductivity or semi-insulating structures such as enhancement mode MESFET and HEMT type devices and it may be useful for the in-situ characterization of epigrown surfaces and interfaces