Effects of 42 hr of total sleep deprivation on component processes of verbal working memory.

The current investigation examined changes in working memory (WM) component processes following total sleep deprivation (TSD) in a sample of healthy young persons. Forty subjects were administered a verbal form of a continuous recognition test (CRT) before and after 42 hr of TSD. Parameters of a computational model of the CRT reflecting attention, WM span, and rate of episodic memory encoding were estimated for each individual. Subjects made more errors on the test following sleep deprivation. Analysis of model parameters revealed statistically independent declines in both the attention and WM span parameters, with a larger effect observed for the decline in WM span. Examination of individual profiles suggested that the effects of TSD on verbal WM component processes vary from person to person. Declines in global verbal WM functioning appear to be primarily driven by reduced WM span and attention; however, these effects may be individual-specific. Further applications of the computational model for examining WM component processes with sleep deprivation and other clinical populations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

野蔷薇中山奈酚含量测定方法的研究

建立了一种简单、快速测定野蔷薇果中黄酮类化合物山奈酚含量的反相液相色谱方法。利用乙腈、水(磷酸调pH为3.0)以1mL/min流速梯度洗脱,在360nm检测波长下,山奈酚在2.5min内即可达到基线分离。经与标准品对照,野蔷薇果中含有山奈酚,含量为4.3μg/g干质量。经测定:山奈酚回收率较好,为94.5%;相对标准偏差小于5%,方法重复性较好,可用于野蔷薇果中黄酮类化合物山奈酚的快速分析检测。以及测量山奈酚含量的分光光度法和高效液相色谱法进了比较研究,结果表明,两种方法测定的山奈酚浓度值差异不大,结果稳定可靠。分光光度法操作简单方便,测定结果略微偏高,HPLC法重复性、稳定性均较好。     

Tunable Dopants with Intrinsic Counterion Separation Reveal the Effects of Electron Affinity on Dopant Intercalation and Free Carrier Production in Sequentially Doped Conjugated Polymer Films

Carrier mobility in doped conjugated polymers is limited by Coulomb interactions with dopant counterions. This complicates studying the effect of the dopant's oxidation potential on carrier generation because different dopants have different Coulomb interactions with polarons on the polymer backbone. Here, dodecaborane (DDB)‐based dopants are used, which electrostatically shield counterions from carriers and have tunable redox potentials at constant size and shape. DDB dopants produce mobile carriers due to spatial separation of the counterion, and those with greater energetic offsets produce more carriers. Neutron reflectometry indicates that dopant infiltration into conjugated polymer films is redox‐potential‐driven. Remarkably, X‐ray scattering shows that despite their large 2‐nm size, DDBs intercalate into the crystalline polymer lamellae like small molecules, indicating that this is the preferred location for dopants of any size. These findings elucidate why doping conjugated polymers usually produces integer, rather than partial charge transfer: dopant counterions effectively intercalate into the lamellae, far from the polarons on the polymer backbone. Finally, it is shown that the IR spectrum provides a simple way to determine polaron mobility. Overall, higher oxidation potentials lead to higher doping efficiencies, with values reaching 100% for driving forces sufficient to dope poorly crystalline regions of the film.     

Dynamic Nondestructive Control of Electronic Component by Liquid Crystal

The work presented in this paper describes an electrothermal bench based upon a liquid crystal sensor. Firstly, general characteristics of the bench are presented. A detailed attention is devoted to the problem of calibration and to the algorithm that permit the determination of the temperature. The validation of this bench has been realized by comparison with infrared microscope measurements. An example of the application is given for a hybrid electronic component. To finish we show that this nondestructive control has permitted us the detection of a design defect in the component.     

SentiML ++: an extension of the SentiML sentiment annotation scheme

The amount of opinionated data on the web has exponentially increased especially after the emergence of online social networks. To deal with these huge deluge of data, we need to have robust mechanisms that can help identify all aspects of opinion segment and support the automatic processing of opinion data. Recently, there have been a few developments made in this direction, and different sentiment annotation schemes have been proposed such as the SentiML, OpinionMiningML, and EmotionML. In this work, we propose SentiML++, an extension of SentiML with a focus on annotating opinions, and further answering aspects of the general question “who has what opinion about whom in which context?”. A detailed comparison with SentiML and other existing annotation schemes is also presented. The data collection annotated with SentiML has been annotated with SentiML++ and is available for download for further research purposes. Experiments with data collections annotated with SentiML and SentiML++ proves that SentiML++ is a significant and valuable addition to SentiML.     

Power-aware scoreboard alternatives for multimedia processors

Intel’s XScale which has powered many multimedia applications uses scoreboard to control instruction execution. Scoreboard stalls the pipeline whenever a source operand or functional unit is needed but not available. While waiting for the availability of the resources, the processor accesses the scoreboard every cycle. Such accesses consume energy without contributing to performance. We address this inefficiency by investigating stall behaviour and introduce an adaptive technique to avoid regular access to the scoreboard during stall periods. Our study shows that by using our technique and for the representative subset of MiBench benchmark suite studied here, it is possible to reduce scoreboard energy consumption by up to 33% while maintaining performance cost within 0.25%.     

An investigation of the titanium effect on the structural and magnetic properties of BaNi2 based W-type hexaferrites

The polycrystalline samples of the composition Ba(Ni_1?xTi_x)₂Fe₁₆O₂₇ were prepared by the conventional ceramic method with (x = 0.0–1.0). Effects of titanium (Ti) doping on structural and magnetic properties of BaNi₂ based W-type hexaferrites were analyzed. The samples were initially sintered in air at 1000 °C for 4 h and finally at 1300 °C for 9 h. The X-ray diffraction patterns confirm the presence of single W-hexagonal phase. The lattice parameters ‘a’ and ‘c’ were found to show irregular behavior by increasing Ti content. The variations of magnetic properties were observed by analyzing hysteresis loop of prepared samples. The results show that maximum magnetization (M) and remanence (M_r) decrease up to x ≤ 0.6 due to replacement of Ti ions for spin down (4f₂) and spin up (12k, 2a and 2b) sublattices, but a substantial increase of M and M_r for (x = 0.8 and1.0) could be attributed to the replacement of Ti ions for spin down sublattices (4f₂). The coercivity (H_c) was found to decrease with increasing Ti content. An increase of grain size with Ti content was also observed. Since, H_c is inversely proportional to the packing fraction of magnetic materials or the grain size.     

An efficient algorithm to calculate intrinsic thermoelectric parameters based on Landauer approach

The Landauer approach provides a conceptually simple way to calculate the intrinsic thermoelectric (TE) parameters of materials from the ballistic to the diffusive transport regime. The approach relies on the calculation of the number of propagating modes and the mean free path for each mode. The modes are calculated from the energy dispersion (E(k)) of the materials, which require heavy computation and are often restricted to energy relations on sparse momentum (k) grids. Here an efficient method to calculate the distribution of modes (DOM) from a given E(k) relationship is presented. The two main features of this algorithm are: (i) its ability to work on sparse dispersion data, and (ii) creation of an energy grid for the DOM that is almost independent of the dispersion data therefore allowing for efficient and fast calculation of TE parameters. The effect of K-grid sparsity on the compute time for DOM and on the sensitivity of the calculated TE results are provided. The algorithm calculates the TE parameters within 5% accuracy when the K-grid sparsity is increased up to 60% for all the dimensions (3D, 2D and 1D). The time taken for the DOM calculation is strongly influenced by the transverse K density (K perpendicular to transport direction) but is almost independent of the transport K density (along the transport direction). The DOM and TE results from the algorithm are bench-marked with, (i) analytical calculations for parabolic bands, and (ii) realistic electronic and phonon results for Bi₂Te₃.     

Chlorine exchange resins

The authors have prepared high polymers which contain a labile chlorine atom. The active group in these polymers is the >NH or —NH₂ group, which takes up chlorine from a chlorine-rich environment, and in the chlorinated form gives up chlorine to an environment deficient in chlorine, for example which exhibits a chlorine demand. The resins, which may be natural or synthetic, act as an agent for chlorine transfer to or from a medium. The results of a preliminary investigation of the utility of various polyamides and amino resins are given. Mass transfer rate studies of chlorine uptake by a urea-melamine-formaldehyde resin and of chlorine liberation from a chlorinated resin of the same type, the effect of pH on these rates, and the practical maximum chlorine capacities are presented. The stability of chlorinated resins is described.     

Synthesis and Crystal Structures of a Lanthanum(III) 1D Polymer and a Mixed-Ligand Cerium(III) Binuclear Complex Derived from Pyridine-2,6-dicaboxylic Acid

Lanthanum(III) and cerium(III) complexes of pyridine-2,6-dicaboxylic acid (H₂Pydc) have been prepared and their crystal structures were determined by X-ray crystallography. The single crystal analysis reveals that the lanthanum(III) complex, 1 is polymeric consisting of {[La(Pydc)₂(H₂O)₂]·4H₂O} _n units linked through carboxylate oxygen atoms and exhibiting nine coordination number. Intermolecular O–H···O hydrogen bonds produce R ₁ ¹ (6), R ₄ ⁴ (16) and R ₄ ⁴ (20) rings, which lead to three-dimensional polymeric chains. The crystal structure of the cerium(III) complex, 2 [{Ce(Pydc)₃}{Ce(Pydc)(HO–CH₂CH₂–OH)(H₂O)₃}·6H₂O)] shows that the complex is a mixed-ligand binuclear system in which one cerium coordinated to three Pydc molecules, while the other cerium is bound to one Pydc, one oxygen atom of the other Pydc, one ethylene glycol and three water molecules. Each of the two Ce(III) ions is nine coordinated. Intermolecular O–H···O hydrogen bonds produce R ₂ ² (8) and R ₂ ² (20) rings, which lead to three-dimensional polymeric chains. The complexes were further investigated using elemental analysis, FTIR spectroscopy and thermogravimetric analysis.