Computed structures of polyimides model compounds

Using a semi-empirical approach, a computer study was made of 8 model compounds of polyimides. The compounds represent subunits from which NASA Langley Research Center has successfully synthesized polymers for aerospace high performance material application, including one of the most promising, LARC-TPI polymer. Three-dimensional graphic display as well as important molecular structure data pertaining to these 8 compounds are obtained

Was the Federal Reserve Fettered? Devaluation Expectations in the 1932 Monetary Expansion

A key question about the Great Depression is whether expansionary monetary policy in the United States would have led to a loss of confidence in the U. S. commitment to the gold standard. This paper uses the $1 billion expansionary open market operation undertaken in the spring of 1932 as a crucial case study of the link between monetary expansion and expectations of devaluation. Data on forward exchange rates are used to measure expectations of devaluation during this episode. We find little evidence that the large monetary expansion led investors to believe that the United States would devalue. The financial press and the records of the Federal Reserve also show little evidence of expectations of devaluation or fear of a speculative attack. We find that a flawed model of the effects of monetary policy and conflict among the twelve Federal Reserve banks, rather than concern about the gold standard, led the Federal Reserve to suspend the expansionary policy in the summer of 1932.

Implantable RF-coiled chip packaging

In this paper, we present an embedded chip integration technology that utilizes silicon housings and flexible parylene radio frequency (RF) coils. As a demonstration of this technology, a flexible parylene RF coil has been integrated with an RF identification (RFID) chip. The coil has an inductance of 16 μH, with two layers of metal completely encapsulated in parylene-C. The functionality of the embedded chip is verified using an RFID reader module. Accelerated-lifetime soak testing has been performed in saline, and the results show that the silicon chip is well protected and the lifetime of our parylene-encapsulated RF coil at 37 °C is more than 20 years

Improved Semantic Representations From Tree-Structured Long Short-Term Memory Networks

Because of their superior ability to preserve sequence information over time, Long Short-Term Memory (LSTM) networks, a type of recurrent neural network with a more complex computational unit, have obtained strong results on a variety of sequence modeling tasks. The only underlying LSTM structure that has been explored so far is a linear chain. However, natural language exhibits syntactic properties that would naturally combine words to phrases. We introduce the Tree-LSTM, a generalization of LSTMs to tree-structured network topologies. Tree-LSTMs outperform all existing systems and strong LSTM baselines on two tasks: predicting the semantic relatedness of two sentences (SemEval 2014, Task 1) and sentiment classification (Stanford Sentiment Treebank).Comment: Accepted for publication at ACL 201

Environmental effects of the Manganui ski field, Mt Taranaki/Egmont

During May 2012, the environmental effects of the Manganui ski field were examined. Permanent quadrats first established in 1974 to monitor vegetation changes were re-measured, vegetation mapping was conducted, modifications to ground form and drainage were identified, soil compaction was examined, and stream water from the ski field catchment was tested for nutrient enrichment. This report focusses primarily on the lower Manganui ski field, as the upper Manganui ski field consists mostly of unmodified herbfield or gravelfield, protected by a sufficient snow base over the winter months. The lower Manganui ski field has a long history of modification spanning from the early 1900s. Vegetation types mapped on the lower field included unmown tussockfield, mown tussock-herbfield, shrubland and exotics. The re-measurement of vegetation in permanent quadrats on the lower field suggests that since the last re-measurement in 1994, several exotic species have increased in cover, including Carex ovalis, Poa annua, and Agrostis capillaris (percentage cover increases of up to 46.6%, 42.0% and 20.7% respectively). Vegetation mapping and historic photographs indicate that the lower ski field sits within the elevational belt of shrubland vegetation, little of which remains due to regular mowing conducted on the field since 1947. Shrubs which have been largely excluded from the field through mowing include Brachyglottis elaeagnifolius, Hebe odora, Ozothamnus vauvilliersii, Dracophyllum filifolium, Pseudopanax colensoi, Raukaua simplex and Hebe stricta var. egmontiana. Areas of the ski field dominated by exotic vegetation were predominantly associated with historic culvert construction and rock dynamiting. Compaction by machinery was confined to the sensitive mossfield area at the base of the lower field

Spinon-Holon binding in t−Jt-J model

Using a phenomenological model, we discuss the consequences of spinon-holon binding in the U(1) slave-boson approach to $t-J$ model. Within a small $x$ ($x=$ hole concentration) expansion, we show that spinon-holon binding produces a pseudo-gap normal state with a segmented Fermi surface and the superconducting state is formed by opening an "additional" d-wave gap on the segmented Fermi surface. The d-wave gap merge with the pseudo-gap smoothly as temperature $T\to0$. The quasi-particles in the superconducting state are coupled to external electromagnetic field with a coupling constant of order $x^{\gamma}$ where $0\leq\gamma\leq1/2$, depending on the strength of the effective spinon-holon binding potential.Comment: 9 pages, 3 figure

Complete gradient-LC-ESI system on a chip for protein analysis

This paper presents the first fully integrated gradient-elution liquid chromatography-electrospray ionization (LC-ESI) system on a chip. This chip integrates a pair of high-pressure gradient pumps, a sample injection pump, a passive mixer, a packed separation column, and an ESI nozzle. We also present the successful on-chip separation of protein digests by reverse phase (RP)-LC coupled with on-line mass spectrometer (MS) analysis

Corrosion Behavior of Parylene-Metal-Parylene Thin Films in Saline

In this paper, we study the corrosion behavior of parylene-metal-parylene thin films using accelerated-lifetime soak tests. The samples under test are thin film resistors with a 200 nm layer of Au sandwiched by parylene-C on both sides, fabricated with parylene-metal skin technology. The samples are tested in hot saline both passively and actively, and different failure modes are observed using optical and electron-beam metrologies. Bubbles and delamination are first seen in the samples after 2 days of soaking under passive conditions, and followed by metal corrosion. While under active conditions, either bubbles or parylene breakdowns are observed depending on the thickness of parylene packaging. These results contribute to a better understanding of the failure mechanisms of parylene packaging in body fluids

Synthesis of 2-Substituted 9-Oxa-Guanines {5-Aminooxazolo 5,4-D Pyrimidin-7(6H)-Ones} and 9-Oxa-2-Thio-Xanthines{5-Mercaptooxazolo 5,4-D Pyrimidin-7(6H)-Ones}

Oxazolo[5,4-d] pyrimidines can be considered as 9-oxa-purine analogs of naturally occurring nucleic acid bases. Interest in this ring system has increased due to recent reports of biologically active derivatives. In particular, 5-aminooxazolo[5,4-d]pyrimidine-7(6H)-ones (9-oxa-guanines) have been shown to inhibit ricin. The preparation of a series of 2-substituted 5-aminooxazolo[5,4-d] pyrimidin-7(6H)-ones and related 5-thio-oxazolo[5,4-d] pyrimidines is described, including analogs suitable for further elaboration employing "click" chemistry utilizing copper-catalyzed Huisgen 1,3-dipolar cycloadditions. Two of the compounds prepared were found to inhibit ricin with IC(50) ca. 1-3 mM.Pharmac

Does the use of summative peer assessment in collaborative group work inhibit good judgement?

The accuracy and consistency of peer marking, particularly when students have the power to reward (or penalise) during formative and summative assessment regimes, is largely unknown. The objective of this study is to evaluate students’ ability and behaviour in marking their peers’ teamwork performance in a collaborative group assessment context both when the mark is counted and not counted towards their final grade. Formative and summative assessment data were obtained from 98 participants in anonymous self and peer assessment of team members’ contributions to a group assessment in business courses. The findings indicate that students are capable of accurately and consistently judging their peers’ performance to a large extent, especially in the formative evaluation of the process component of group work. However, the findings suggest significant peer grading bias when peer marks contribute to final grades. Overall, findings suggest that students are reluctant to honestly assess their peers when they realise that their actions can penalise non-contributing students. This raises questions about the appropriateness of using peer marks for summative assessment purposes. To overcome the problems identified, this paper proposes a number of measures to guide educators in effectively embedding summative peer assessment in a group assessment contex