cssi/SciSciGPT-SciSciNet huggingface dataset:
Photoemission investigation of amorphous Si and Ge

Abstract Photoelectron energy distribution curves (EDC's) from electron gun evaporated amorphous and annealed polycrystalline Si films are compared to the corresponding curves for Ge over a photon energy range from 6.5 to 11.7 eV. The EDC's of amorphous Si and Ge as well as the derived optical density of states show a sharp valence band edge but otherwise none of the characteristic peaked structure of the crystalline materials. In situ comparisons to EDC's of Au accurately locate the Fermi level and monitor instrumental resolution allowing an upper limit of 3 × 1019 states/cm3-eV to be placed on the density of states in the energy gap of amorphous Si. EDC's typical of the crystal were obtained from Ge, which showed a rather abrupt amorphous to crystalline transition, by annealing to 300°C and from Si, which showed a more gradual transition, by annealing to 625°C. EDC's from amorphous and annealed Ge films reveal only minor dependence on evaporation rates of 2 and 26 A/sec and on substrate temperature over the range — 170 to 150 °C.
Evidence of cholesterol accumulated in high curvature regions : Implication to the curvature elastic energy for lipid mixtures

Recent experiments suggested that cholesterol and other lipid components of high negative spontaneous curvature facilitate membrane fusion. This is taken as evidence supporting the stalk-pore model of membrane fusion in which the lipid bilayers go through intermediate structures of high curvature. How do the high-curvature lipid components lower the free energy of the curved structure? Do the high-curvature lipid components modify the average spontaneous curvature of the relevant monolayer, thereby facilitate its bending, or do the lipid components redistribute in the curved structure so as to lower the free energy? This question is fundamental to the curvature elastic energy for lipid mixtures. Here we investigate the lipid distribution in a monolayer of a binary lipid mixture before and after bending, or more precisely in the lamellar, hexagonal, and distorted hexagonal phases. The lipid mixture is composed of 2:1 ratio of brominated di18:0PC and cholesterol. Using a newly developed procedure for the multiwavelength anomalous diffraction method, we are able to isolate the bromine distribution and reconstruct the electron density distribution of the lipid mixture in the three phases. We found that the lipid distribution is homogenous and uniform in the lamellar and hexagonal phases. But in the distorted hexagonal phase, the lipid monolayer has nonuniform curvature, and cholesterol almost entirely concentrates in the high curvature region. This finding demonstrates that the association energies between lipid molecules vary with the curvature of membrane. Thus, lipid components in a mixture may redistribute under conditions of nonuniform curvature, such as in the stalk structure. In such cases, the spontaneous curvature depends on the local lipid composition and the free energy minimum is determined by lipid distribution as well as curvature.
Dislocation mechanisms for deformation twinning in the L10 structure

Extended superlattice intrinsic stacking fault (SISF) strips resulting from the planar dissociation of two types of glissile superdislocations and a sessile ordinary dislocation are analyzed on the basis of the elastic anisotropy, the effect of applied stress, and the relative dislocation mobility. Dislocation mechanisms for twin nucleation are discussed with a special reference to the apparent CRSS measured on Ti-56Al single crystals. Available experimental results on twin formation in {gamma}-phase TiAl alloys are summarized. The highlights of this paper are: (1) Spontaneous dissociation of a [110]/2 edge dislocation into Frank-Shockley partials is favorable in L1{sub 0} alloys, including TiAl (c/a > 1), because of the repulsive interaction in the direction normal to the (111) plane due to the elastic anisotropy of non-cubic symmetry. (2) A pileup of superdislocations of the (111)[10{bar 1}] type against either a Lomer-Cottrell type barrier, or a forest dislocation of [110]/2 type, is envisaged to initiate the necessary internal stress concentration. (3) The early stages of twin formation by a pole mechanism are geometrically and energetically easier to overcome in L1{sub 0} alloys than in fcc metals and alloys. (4) No conclusive experimental evidence for any specific twin nucleation mechanism in the L1{sub 0} structure exists,more » but the recent TEM results on TiAl are in support of pole mechanisms, a pileup mechanism, and an overlapping mechanism.« less
The genetics of self-incompatibility in Oenothera rhombipetala

Pollen tubes were grown under controlled temperatures in stigmas and styles which had been cut from the flowers at the point of juncture of the style with the ovary. At constant temperatures the tubes compatible with the styles grew rapidly at uniform rates. They showed accelerated growth with increase in temperature within the range 10°–30°C. Growth of incompatible tubes was irregular and slow and was neither measurably accelerated nor depressed within this range of temperatures. Routine tests for compatibility were conducted at 27°C; at this temperature compatible tubes grew through the entire length of the styles (ca. 58 mm) in 9 hours. Much of the incompatible pollen failed to germinate; that which did, grew to a maximum length ofca. 2 mm inca. 4 hours. The incompatible tubes did not even enter the styles but remained confined to the stigmas. ThreeS alleles were involved and conformed in their behavior to the gametophytic system of incompatibility. Colchicine-induced tetraploid derivatives of these plants showed no increase in compatibility.
"Twitter Archeology" of learning analytics and knowledge conferences

The goal of the present study was to uncover new insights about the learning analytics community by analyzing Twitter archives from the past four Learning Analytics and Knowledge (LAK) conferences. Through descriptive analysis, interaction network analysis, hashtag analysis, and topic modeling, we found: extended coverage of the community over the years; increasing interactions among its members regardless of peripheral and in-persistent participation; increasingly dense, connected and balanced social networks; and more and more diverse research topics. Detailed inspection of semantic topics uncovered insights complementary to the analysis of LAK publications in previous research.
Etched cladding tunable fiber Bragg grating filters integrated with Si V-grooves

We describe a novel electrically tunable fiber Bragg grating (FBG) filter with a chemically etched cladding and an evaporated metal coating on one side of the fiber. Wavelength tuning ranges up to 2.5 nm with efficiencies greater than 8.5 nm/watt have been demonstrated along with modulation bandwidths up to 14 Hz. We have also demonstrated tuning efficiencies over 200nm/Watt for 30micrometers diameter etched cladding devices tuned under moderate vacuum conditions. Such tunable FBG filters have potential applications in dense wavelength division multiplexing (DWDM), optical signal processing, or in wavelength tunable fiber lasers. In our paper we investigate the tuning efficiency and modulation bandwidth of etched cladding FBGs integrated with Silicon V-grooves that utilize temperature tuning of the filter. By passing an electrical current through a thin metal coating deposited onto an etched cladding FBG, the temperature of the grating can be controlled to tune the spectral characteristics of the FBG. Additionally, to simplify the fabrication process, we evaporate the metal coating onto the etched FBG from only one side. This radially asymmetric metal coating is simpler to fabricate, since it does not require any mechanical fixture to rotate the fiber during metal deposition. The etched cladding FBG is placed in a Si V-groove that serves the multiple functions of holding the FBG during etching and evaporation, and also provides a simple and compact means for scaling up to arrays of tunable FBGs.
Gender differences: emotional expression and feelings of personal inauthenticity

This survey study examined the emotional expression content of human resources jobs and how the content varies by gender. On the basis of findings, it appeared that women more often conform to feminine display rules, which require the suppression of negative emotions and the simulation of positive emotions. In contrast, men more often adopted masculine display rules, which require the suppression of positive emotions and the simulation of negative ones. For both men and women, emotional dissonance generated by a feminine display-rule pattern was positively correlated with feelings of personal inauthenticity at work. Gender modified the relationship between emotional dissonance and gender only in that women who adopted the masculine display-rule pattern reported feeling the least personally inauthentic of all.
Improving the Erdős–Ginzburg–Ziv theorem for some non-abelian groups

Abstract Let G be a group of order m. Define s ( G ) to be the smallest value of t such that out of any t elements in G, there are m with product 1. The Erdős–Ginzburg–Ziv theorem gives the upper bound s ( G ) ⩽ 2 m − 1 , and a lower bound is given by s ( G ) ⩾ D ( G ) + m − 1 , where D ( G ) is Davenport's constant. A conjecture by Zhuang and Gao [J.J. Zhuang, W.D. Gao, Erdős–Ginzburg–Ziv theorem for dihedral groups of large prime index, European J. Combin. 26 (2005) 1053–1059] asserts that s ( G ) = D ( G ) + m − 1 , and Gao [W.D. Gao, A combinatorial problem on finite abelian groups, J. Number Theory 58 (1996) 100–103] has proven this for all abelian G. In this paper we verify the conjecture for a few classes of non-abelian groups: dihedral and dicyclic groups, and all non-abelian groups of order pq for p and q prime.
The physical aspects of low noise electronics

Abstract Quantum effects are beginning to play a role in the newer forms of low noise amplifiers. The ultimate noise performance of these amplifiers has been variously treated on the bases of spontaneous emission and zero-point energy to give a lower limit of noise temperature Tn = (1/ln 2) (hv/k). It can be shown very generally, though, that the uncertainty principle of quantum mechanics can be used to prove that every linear amplifier adds some noise. Moreover, the minimum noise temperature of any linear amplifier can be shown to be T n = In 2-1/G 1-1/G −1 hv K The proper evaluation of this result requires a quantum theory of communication which does not yet exist.
Increasing agility in unmanned ground vehicles using variable internal mass and inertial properties

Unmanned Ground Vehicles (UGV) that possess agility, or the ability to quickly change directions without a significant loss in speed, would have several advantages in field operations over conventional UGVs. The agile UGVs would have greater maneuverability in cluttered environments and improved obstacle avoidance capabilities. The UGVs would also be able to better recover from unwanted dynamic behaviors. This paper presents a novel method of increasing UGV agility by actively altering the location of the vehicle's center of mass during locomotion. This allows the vehicle to execute extreme dynamic maneuvers by controlling the normal force acting on the wheels. A theoretical basis for this phenomenon is presented and experimental results are shown that validate the approach.
A fusion propulsion system for rapid interplanetary travel

Abstract A propulsion system with capabilities that far exceed conventional and nuclear thermal systems is proposed for human exploration of the solar system and beyond. It makes use of fusion nuclear reactions, and is based on the magnetic mirror configuration which was studied extensively as a potential terrestrial power reactor. Unlike the conventional mirror machine, however, the proposed device will confine a plasma of such density and temperature as to make the ion-ion collision mean free path much shorter than the plasma length. Under these conditions the plasma behaves like a fluid and its escape from the machine is analogous to the flow of a gas into vacuum from a vessel with a hole, hence the name gasdynamic mirror (GDM) (See Fig. 1). Recent studies of this system reveal that the conditions for its performance as a propulsion system are much less stringent than those imposed by an economically viable power reactor. This is reflected by the small energy magnification factor Q (ratio of fusion power to injected power) required by the propulsion system when compared to that of the power reactor. The plasma confinement in this device is provided by a magnetic field that is stronger at the ends than it is at the center thereby providing the necessary reflecting force for containment while allowing a certain fraction of the energetic particles to escape to generate the thrust. The plasma dynamics and the corresponding propulsion characteristics of GDM can be obtained from a set of coupled conservation equations which yield, among other things, the specific impulse and thrust of such an engine. Typical values of the specific impulse is 1.26 × 105 seconds and a thrust of tens of kilonewtons for a system with a dry mass of about 230mT. Such a propulsion system is shown to be about 44 m long and to make a round trip to Mars in less than five months. In this paper we examine the various physics and engineering considerations that lead to the modest vehicle mass noted above.
Language Revitalisation in the Andes: Can the Schools Reverse Language Shift?.

Quechua, often known as the language of the Incas, remains today a vital language with over 10 million speakers in several Andean republics. Nevertheless, census records and sociolinguistic studies document a continuous cross-generational shift from Quechua monolingualism to Spanish monolingualism in the latter half of the twentieth century, at both individual and community levels. An increasing awareness of the potential threat to the language has led to a variety of new initiatives for Quechua revitalisation in the 1990s, initiatives which go beyond earlier experimental bilingual education projects designed primarily to provide mother tongue literacy instruction to indigenous children (in transitional or maintenance programs) to larger or more rooted efforts to extend indigenous language and literacy instruction to new speakers as well. Drawing on documents, interviews, and on-site participant observation, this paper will review and comment on two recent such initiatives: Bolivia s 1994 national educati...
Notes: A note on collections of graphs with non-surjective lambda labelings

The λ-number of a graph G, denoted λ(G), is the smallest integer k such that there exists a function from V(G) into {0, 1, 2,..., k} under which adjacent vertices receive integers which differ by at least 2 and vertices at distance two receive integers which differ by at least 1. We establish the infinitude of the collection of connected graphs G with fixed maximum degree Δ ≥ 4 and fixed λ-number Δ + t, 1 ≤ t ≤ Δ - 1 such that no λ-labeling of G into {0, 1, 2,...., λ(G)} is surjective. Also, from among graphs with no surjective λ-labelings, we construct connected graphs with maximum degree 3, λ-number 5 and arbitrarily large order.
The nature and energies of gap states in a-Si:H

Abstract The results concerning gap states in hydrogenated amorphous silicon ( a -Si:H) presented at the 12th ICALS are discussed in the light of other information about the electronic structure of this material. Arguments for and against the overcoordinated floating bond are presented as well as models explaining the conflicting energy assignments of the defect states.
Microstructural and Stress Corrosion Cracking Characteristics of Austenitic Stainless Steels Containing Silicon

Austenitic stainless steels (SSs) core internal components in nuclear light water reactors (LWRs) are susceptible to irradiation-assisted stress corrosion cracking (IASCC). One of the effects of irradiation is the hardening of the SS and a change in the dislocation distribution in the alloy. Irradiation may also alter the local chemistry of the austenitic alloys; for example, silicon may segregate and chromium may deplete at the grain boundaries. The segregation or depletion phenomena at near-grain boundaries may enhance the susceptibility of these alloys to environmentally assisted cracking (EAC). The objective of the present work was to perform laboratory tests in order to better understand the role of Si in the microstructure, properties, electrochemical behavior, and susceptibility to EAC of austenitic SSs. Type 304 SS can dissolve up to 2 pct Si in the bulk while maintaining a single austenite microstructure. Stainless steels containing 12 pct Cr can dissolve up to 5 pct bulk Si while maintaining an austenite structure. The crack growth rate (CGR) results are not conclusive about the effect of the bulk concentration of Si on the EAC behavior of SSs.
Use of Chelating Diphosphines To Prepare New Phosphido Clusters of Aluminum and Gallium

Novel phosphido cluster complexes of formula (Me2M)4(μ-(1,2-PR)2C6H4)2 (M = Al, R = Me (1); M = Ga, R = t-Bu (2)) result when the chelating diphosphine ligand 1,2-bis(alkylphosphino)benzene is mixed with trialkylaluminum and -gallium reagents. When the potentially chelating ligand 1,2-bis(tert-butylphosphino)ethane is mixed with 2 equiv of AlMe3 under the same conditions, the secondary phosphine bis-adduct complex Me3Al·PH(t-Bu)CH2CH2(t-Bu)HP·AlMe3 (3) is formed.
Temperature of limpets in the rocky intertidal zone:Effects of caging and substratum

Depending on weather, temperatures (Te) of intertidal limpets (Collisella scabra) were decreased as much as 4°C by the types of cages used in ecological studies in the rocky intertidal zone. The cages blocked 60–80% of incident solar radiation. Differences in substratum may have larger effects on Te, however, than those introduced by cages.
Apoptosis-inducing factor (AIF) is targeted in IFN-α2a-induced Bid mediated apoptosis through Bak activation in ovarian cancer cells

Previously we have shown that interferon (IFN)-α induced apoptosis is predominantly mediated by the upregulation of tumor necrosis factor related apoptosis-inducing ligand (TRAIL) via the caspase-8 pathway. It was also shown that recruitment of mitochondria in IFN-α induced apoptosis involves the cleavage of BH3 interacting domain death agonist (Bid) to truncated Bid (tBid). In the present study, we demonstrate that tBid induced by IFN-α2a activates mitochondrial Bak to trigger the loss of mitochondrial membrane integrity, consequently causing release of apoptosis-inducing factor (AIF) in ovarian cancer cells, OVCAR3. AIF translocates from the mitochondria to the nucleus and induces nuclear fragmentation and cell death. Both a small molecule Bid inhibitor (BI-6C9) or Bid-RNA interference (RNAi) preserved mitochondrial membrane potential, prevented nuclear translocation of AIF, and abrogated IFN-α2a-induced cell death. Cell death induced by tBid was inhibited by AIF-RNAi, indicating that caspase-independent AIF signaling is the main pathway through which Bid mediates cell death. This was further supported by experiments showing that BI-6C9 did not prevent the release of cytochrome c from mitochondria to cytosol, while the release of AIF was prevented. In conclusion, IFN-α2a-induced apoptosis is mediated via the mitochondria-associated pathway involving the cleavage of Bid followed by AIF release that involves Bak activation and translocation of AIF from the mitochondria to the nucleus in OVCAR3 cells.
Depth of root symbiont occurrence in soil.

The woody legume Prosopis glandulosa (mesquite) growing in the California Sonoran Desert develops functional root symbiotic associations (N2-fixing nodules, vesicular-arbuscular mycorrhizal fungi) at depths greater than 4 m in moist soil above a seasonally stable water table. Population densities of symbiotic microorganisms are substantially greater at depth than near the surface. Inferences of plant symbiotic dependence based upon examination of surface roots and soil may be incorrect since deep roots can support the symbioses which are critical for plants utilizing deep water.
Video anywhere: a system for searching and managing distributed heterogeneous video assets

Visual information, especially videos, plays an increasing role in our society for both work and entertainment as more sources become available to the user. Set-top boxes are poised to give home users access to videos that come not only from TV channels and personal recordings, but also from the Internet in the form of downloaded and streaming videos of various types. Current approaches such as Electronic Program Guides and video search engines search for video assets of one type or from one source. The capability to conveniently search through many types of video assets from a large number of video sources with easy-to-use user profiles cannot be found anywhere yet. VideoAnywhere has developed such a capability in the form of an extensible architecture as well as a specific implementation using the latest in Internet programming (Java, agents, XML, etc.) and applicable standards. It automatically extracts and manages an extensible set of metadata of major types of videos that can be queried using either attribute-based or keyword-based search. It also provides user profiling that can be combined with the query processing for filtering. A user-friendly interface provides management of all system functions and capabilities. VideoAnywhere can also be used as a video search engine for the Web, and a servlet-based version has also been implemented.
Radiative β decay for studies of CP violation

A triple-product correlation in the radiative $\ensuremath{\beta}$ decay rate of neutrons or of nuclei, characterized by the kinematical variable $\ensuremath{\xi}\ensuremath{\equiv}({\mathbf{l}}_{\ensuremath{\nu}}\ifmmode\times\else\texttimes\fi{}{\mathbf{l}}_{e})\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{k}$, where, e.g., $n(p)\ensuremath{\rightarrow}p({p}^{\ensuremath{'}})+{e}^{\ensuremath{-}}({l}_{e})+{\overline{\ensuremath{\nu}}}_{e}({l}_{\ensuremath{\nu}})+\ensuremath{\gamma}(k)$, can be generated by the pseudo-Chern-Simons term found by Harvey, Hill, and Hill as a consequence of the baryon vector current anomaly and $SU(2{)}_{L}\ifmmode\times\else\texttimes\fi{}U(1{)}_{Y}$ gauge invariance at low energies. The correlation probes the imaginary part of its coupling constant, so that its observation at anticipated levels of sensitivity would reflect the presence of sources of $CP$ violation beyond the standard model. We compute the size of the asymmetry in $n\ensuremath{\rightarrow}p{e}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{e}\ensuremath{\gamma}$ decay in chiral effective theory, compare it with the computed background from standard-model final-state interactions, and consider the new physics scenarios which would be limited by its experimental study.
A Minimalist Approach to MALDI Imaging of Glycerophospholipids and Sphingolipids in Rat Brain Sections

Abstract Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful tool that has allowed researchers to directly probe tissue molecular structure and drug content with minimal manipulations, while maintaining anatomical integrity. In the present work glycerophospholipids and sphingolipids images were acquired from 16-μm thick coronal rat brain sections using MALDI-MS. Images of phosphatidylinositol 38:4 (PI 38:4), sulfatide 24:1 (ST 24:1), and hydroxyl sulfatide 24:1 (ST 24:1 (OH)) were acquired in negative ion mode, while the images of phosphatidylcholine 34:1 (PC 34:1), potassiated phosphatidylcholines 32:0 (PC 32:0 + K+) and 36:1 (PC 36:1 + K+) were acquired in positive ion mode. The images of PI 38:4 and PC 36:1 + K+ show the preferential distribution of these two lipids in gray matter; and the images of two sulfatides and PC 32:0 + K+ show their preferential distribution in white matter. In addition, the gray cortical band and its adjacent anatomical structures were also identified by contrasting their lipid makeup. The resulting images were compared to lipid images acquired by secondary ion mass spectrometry (SIMS). The suitability of TLC sprayers, Collison Nebulizer, and artistic airbrush were also evaluated as means for matrix deposition.
Aldehydes, Ketones and Esters in Valencia Orange Peel Oil

SUMMARY: The aldehydes, ketones and esters in the volatile portion of Valencia orange oil have been isolated and identified. Seventeen aldehydes and ketones and three esters are included, 10 of which have never been identified as constituents of Valencia oil. Cis- and trans-limonene oxide have also been found to occur in the same fraction. This is the first time that these compounds have been identified in cold-pressed orange oil. A series of five homologous α,β-unsaturated aldehydes were isolated and partially characterized.
Auction, but don't block

This paper argues that ISP's recent actions to block certain applications (e.g. BitTorrent) and attempts to differentiate traffic could be a signal of bandwidth scarcity. Bandwidth-intensive applications such as VoD could have driven the traffic demand to the capacity limit of their networks. This paper proposes to let ISPs auction their bandwidth, instead of blocking or degrading applications. A user places a bid in a packet header based on how much he values the communication. When congestion occurs, ISPs allocate bandwidth to those users that value their packets the most, and charge them the Vickrey auction price. We outline a design that addresses the technical challenges to support this auction and analyze its feasibility. Our analysis suggests that the design have reasonable overhead and could be feasible with modern hardware.
Early detection of chemoradioresponse in esophageal carcinoma by 3'-deoxy-3'-3H-fluorothymidine using preclinical tumor models.

Purpose: Early identification of esophageal cancer patients who are responding or resistant to combined chemoradiotherapy may lead to individualized therapeutic approaches and improved clinical outcomes. We assessed the ability of 3′-deoxy-3′- 18 F-fluorothymidine positron emission tomography (FLT-PET) to detect early changes in tumor proliferation after chemoradiotherapy in experimental models of esophageal carcinoma. Experimental Design: The in vitro and ex vivo tumor uptake of [ 3 H]FLT in SEG-1 human esophageal adenocarcinoma cells were studied at various early time points after docetaxel plus irradiation and validated with conventional assessments of cellular proliferation [thymidine (Thd) and Ki-67] and [ 18 F]FLT micro-PET imaging. Imaging-histologic correlation was determined by comparing spatial Ki-67 and [ 18 F]FLT distribution in autoradiographs. Comparison with fluorodeoxyglucose (FDG) was done in all experiments. Results: In vitro [ 3 H]FLT and [ 3 H]Thd uptake rapidly decreased in SEG-1 cells 24 hours after docetaxel with a maximal reduction of over 5-fold ( P = 0.005). The [ 3 H]FLT tumor-to-muscle uptake ratio in xenografts declined by 75% compared with baseline ( P 3 H]FDG uptake was gradual and less pronounced. Tumor uptake of [ 3 H]FLT was more closely correlated with Ki-67 expression ( r = 0.89, P 3 H]FDG ( r = 0.39, P = 0.08). Micro-PET images depicted similar trends in reduction of [ 18 F]FLT and [ 18 F]FDG tumor uptake. Autoradiographs displayed spatial correlations between [ 18 F]FLT uptake and histologic Ki-67 distribution in preliminary studies. Conclusions: FLT-PET is suitable and more specific than FDG-PET for depicting early reductions in tumor proliferation that precede tumor size changes after chemoradiotherapy.
Implications of Passive Mixer Transparency for Impedance Matching and Noise Figure in Passive Mixer-First Receivers

In this paper, a class of passive mixer-first, LNA-less receivers is analyzed in depth. Quadrature passive mixers are shown to present the impedance of their baseband port to the RF port and vice versa. This transparency property, in combination with resistive feedback differential amplifiers, and “complex” feedback between the I and Q paths, can be used to control the impedance at the RF port. This impedance can be tuned using only baseband components (i.e., resistors). The noise limits of such an architecture are analyzed and simulated, and are shown to be comparable to standard RF-LNA-first receivers. Accounting for the higher harmonics of the LO frequency proves critical in accurately analyzing the behavior of these circuits and their ability to provide an impedance match with low noise figure. Additionally, it is shown that expanding quadrature passive mixers to harmonic rejection mixers allows for even better noise performance and wider matching range.
Design Techniques and Applications of Cyberphysical Systems: A Survey

Cyberphysical systems (CPSs) are new class of engineered systems that offer close interaction between cyber and physical components. The field of CPS has been identified as a key area of research, and CPSs are expected to play a major role in the design and development of future systems. In this paper, we survey recent advancements made in the development and applications of CPSs. We classify the existing research work based on their characteristics and identify the future challenges. We also discuss the examples of prototypes of CPSs. The aim of this survey is to enable researchers and system designers to get insights into the working and applications of CPSs and motivate them to propose novel solutions for making wide-scale adoption of CPS a tangible reality.
Selecting Optimum Sampling and Quantization Intervals for Detecting Impulse Waveforms

The combined use of time-domain waveforms, detection probability, and false-alarm probability as criteria for selecting a sample period and quantization interval which minimizes bit rate is illustrated. This is contrasted with the frequencydomain concepts and mean-square error criteria usually employed in telemetry to choose sample period and quantization interval. The method is applied to a sampled-data alarm system defined in the paper. Its essence is to choose a quantization interval which provides, at minimum bit rate, a prescribed number of nonzero samples following the receipt of an impulse input of specified strength, while maintaining preset detection and false alarm probabilities. The effect of noise on optimum choice is considered. The methodology is flow-charted in detail sufficient that the technique may be applied to other problems.
Simultaneous quantification of F2-isoprostanes and prostaglandins in human urine by liquid chromatography tandem-mass spectrometry.

Abstract A specific and sensitive LC–MS/MS method for analysis of F2-isoprostanes (F2-IsoPs) and prostaglandins (PGs) in urine was developed and validated to examine the levels of F2-IsoPs and prostaglandin F2α (PGF2α), in human urine in patients undergoing cardiac surgery. The rapid extraction for F2-IsoPs and PGs from urine was achieved using a polymeric weak anion solid phase extraction cartridge. The base-line separation of 8-iso-PGF2α, 8-iso-15(R)-PGF2α, PGF2α, and 15(R)-PGF2α was carried out on a Hydro-RP column (250 mm × 2.0 mm i.d., Phenomenex, CA) using a linear gradient of methanol:acetonitrile (1:1, v/v) in 0.1% formic acid at a flow rate of 0.2 mL/min. The method was proved to be accurate and precise for simultaneous quantification of each analyte over a linear dynamic range of 0.05–50 ng/mL with correlation coefficients greater than 0.99. The intra-day and inter-day assay precision at the lowest quality control (0.07 ng/mL) level were less than 17%. The mean extraction recoveries of F2-IsoPs and PGs were in a range of 79–100%. In applications of this method to patients undergoing cardiac surgery, post-surgery urinary concentrations of 8-iso-PGF2α increased significantly in patients (n = 14) who did not develop acute kidney (AKI) (pre-surgery 0.344 ± 0.039 vs. post-surgery 0.682 ± 0.094 ng/mg creatinine, p
Principles and applications of a dynamically focused phased array real time ultrasound system.

The physical principles and clinical applications of a high-resolution, dynamically focused phased-array real time ultrasound system are described. Advantages of the real time technique include rapid survey capability, efficient selection of an appropriate tomographic plane, identification of pulsating structures, and dynamic studies. The capabilities of a high resolution phased array with extended dynamic focusing to a range of 15-20 cm are demonstrated in vascular, abdominal, and obstetric imaging. Appropriate clinical examples showing normal and pathological anatomy are presented. Comparisons with conventional B scans are illustrated.
Effect of Server Introduction on Restaurant Tipping1

The effect of a server introducing herself by name on restaurant tipping was investigated. Forty-two, 2-person dining parties were randomly assigned to either a name or a no name introduction condition. The use of a buffet brunch reduced contact between server and diners and held bill size constant. Results indicated that having the server introduce herself by name resulted in a significantly higher tipping rate (23.4%) than when the server did not introduce herself by name (15.0%), p < .001. Tipping rate also was affected by method of payment, with diners who charged the meal having a higher rate (22.6%) than those paying cash (15.9%), p < .001. The findings suggest the importance of initial server-diner interactions. Possible alternative explanations and suggestions for future research are provided.
Mutual interactions between repeated flurothyl convulsions and electrical kindling

Abstract The interactions between repeated flurothyl seizures and electrical kindling induced from the neocortex or the amygdala were investigated. Three consecutive flurothyl-induced convulsions enhanced the rate of development of subsequent electrical kindling from the neocortex. Similarly multiple (more than 15) generalized kindled seizures, induced from either the neocortex or the amygdala, reduced the latency of onset of flurothyl seizures with repeated exposures producing a ‘kindling-like’ effect for flurothyl. These results indicate that eventually seizures will beget seizures independently of the site of origination of the seizures.
Natural boundary conditions for Lagrangians with reverse time scales

Natural boundary conditions are derived for variation problems which involve Lagrangians with reverse time scale. Both systems with lumped and distributed parameters are considered.
Emerging approaches for treating HER2-positive metastatic breast cancer beyond trastuzumab

Because metastatic breast cancer (MBC) is incurable in most cases, the goals of treatment are improvement in quality of life, management of symptoms, and prolonged survival. The human epidermal growth factor receptor 2 (HER2) is overexpressed in up to 30% of breast tumors, and before the development of HER-targeted therapy, HER2 positivity was predictive of poorer clinical outcomes. Trastuzumab and pertuzumab (anti-HER2 monoclonal antibodies), lapatinib (a small molecule inhibitor of HER2 and the epidermal growth factor receptor [EGFR]) are approved for treating HER2-positive MBC in the United States. Although trastuzumab plus chemotherapy is currently regarded as the first-line standard of care for HER2-positive MBC, it is not without shortcomings; these include its association with certain adverse events (e.g. cardiotoxic effect) and development of resistance. A number of investigational agents that target HER2 and other members of that receptor family are in clinical development for patients with HER2-positive MBC whose disease has progressed on trastuzumab. In addition, in an effort to overcome treatment resistance, clinical trials are evaluating combination therapy (investigational HER-targeted agents with trastuzumab or lapatinib). This review discusses recently completed and ongoing phase II and III clinical trials of investigational HER-targeted agents in the setting of trastuzumab-progressive, HER2-positive MBC.
Postnatal conversion of cross phrenic activity from an active to latent state

Spinal cord hemisection rostral to the phrenic nucleus leads to paralysis of the ipsilateral hemidiaphragm and respiratory insufficiency. Recovery of the paralyzed hemidiaphragm may be induced by activating a latent respiratory motor pathway in adult rats. Although the pathway is latent in adults, it may not be latent in neonatal rats as shown by the spontaneous expression of activity over this pathway in an earlier in vitro study. Activity mediated over the latent pathway is known as "crossed phrenic activity". Whether crossed phrenic activity following C2 spinal cord hemisection occurs spontaneously in the neonatal rat in vivo is still unknown. We hypothesized that crossed phrenic activity may be spontaneously expressed in neonates in vivo and may be converted from a spontaneously active state to a latent and nonfunctional state during postnatal development. Thus, a time course study was designed to analyze this activity in rat pups at different ages. The functional status of the ipsilateral and contralateral hemidiaphragms was tested by EMG analysis following hemisection. Crossed phrenic activity was expressed in ventral, lateral, and dorsal parts of the ipsilateral hemidiaphragm in P2 and some P3 and P4 neonatal rats. During postnatal development, the activity was observed only in the ventral area of the ipsilateral hemidiaphragm in P7, P14, P21 and P28 animals. Significant decreases in the extent of ventral crossed phrenic activity were observed from P2 to P28. The pathway generating this activity becomes latent by postnatal day 35. The present results suggest that spontaneous crossed phrenic activity occurs in vivo following C2 hemisection and the activity gradually decreases during the first four postnatal weeks.
OPAG: Opportunistic Data Aggregation in Wireless Sensor Networks

We propose Opportunistic Data Aggregation (OPAG) that incurs no computation error and tolerates moderate message losses in wireless sensor networks (WSNs). OPAG performs in-network data aggregation in two layers: (1) at the data-aggregation layer, aggregation results are computed accurately; and (2) at the data-routing layer,a WSN node may send intermediate/partial results to its aggregation node using multi-path routing in order to tolerate message losses.By space-multiplexing messages (i.e., padding multiple partial results or sensor readings in a single message), OPAG opportunistically exploits a multi-path routing scheme, which is more energy-efficient than retransmission. This is based on a key observation that, when sending a message, the radio may consume much more energy in idle listening during the backoff period and the time to wait for its acknowledgment than transmitting the data bits.We implemented OPAG on TinyOS 2.x and TMote Sky Mote, and evaluated its performance on the Motelab Testbed at Harvard University.When a network is relatively well connected, OPAG can reduce the energy consumption by 33% at the expense of slightly higher relative errors, compared to TAG with reliable transmission.Compared to synopsis diffusion, OPAG can reduce the aggregation errors by 50% while consuming roughly the same amount of energy.
Age Effects on the Adaptive Response of the Female Rat Heart Following Aortic Constriction

Aging is associated with adaptations in the hearts of mammals that diminish the reserve capacity to meet hemodynamic loading challenges. To evaluate potential mechanisms of this phenomenon, the following hypotheses were tested: compared with hearts of adult rats, hearts of aged rats undergoing aortic constriction will exhibit (a) a lower concentration of myofibrillar proteins, (b) a reduced sensitivity to extracellular calcium, and (c) a reduced coronary perfusion. Female Fischer 344 rats aged 9 months (adult) and 27 months (aged) were assigned to control (C) or aortic-constriction (AC) groups and studied at 7 and 28 days post-AC, yielding six groups of rats. Analysis of variance was used to examine the effects of age and AC. The left ventricular (LV) mass/body mass ratio expressed a percentage of age-matched control value averaged AC-7adult, 111%; AC-28adult, 120%; AC-7aged, 106%; AC-28aged, 123% (AC, p < .01). As a percentage of adult rats values, the pressure-generating capacity of the LV averaged Caged, 99%; AC-7aged, 92%; AC-28aged, 92% (age, p < .05). There were no differences attributable to age or AC in either myofibrillar protein concentration or calcium sensitivity. There was, however, a significantly lower concentration of nonmyofibrillar protein (approximately 10%) in the hearts of all three groups of aged rats compared with the adult rats that was unaltered by AC. The percentages of LV myosin heavy chain in the alpha-isoform were Cadult, 77%; AC-7adult, 66%; AC-28adult, 66%; Caged, 45%; AC-7aged, 41%; AC-28aged, 32% (age, p < .01; AC,p < .01). Coronary flow per gram of tissue averaged 9% lower in all three of the aged groups compared with the adult rats and was not significantly affected by AC (age, p < .05). The data suggest that a reduction in nonmyofibrillar protein and a reduced coronary flow, rather than changes in calcium sensitivity or myofibrillar protein, are associated with an impairment in the adaptive response of the aged heart.
Living With Low Vision: A Personal and Professional Perspective

Unlike most readers of this special issue, I have been both a consumer and provider of rehabilitation services. A retinal hemorrhage that occurred when I was in my late twenties signaled the beginning of delayed-onset retinopathy of prematurity--a condition that has been further complicated since that time. In this article, I offer a glimpse of what living with low vision is like by describing activities in my own life and accommodations I have made. My hope is that therapists will learn more about the realities of living with low vision and will seek our additional information that they will incorporate into their practice.
West Nile Virus in the Americas

Since the first detection of West Nile virus in the Western Hemisphere in 1999, the virus has spread rapidly across the North American continent and as far south as Argentina. An unprecedented pattern of large annual epidemics of human neuroinvasive disease continues in North America, resulting in considerable public health impact. The high infection incidence in humans has resulted in non-mosquito transmission modes, such as through transfused blood and transplanted organs. West Nile virus incursion into Latin America and the Caribbean Islands has resulted in surprisingly low human, avian, and equine morbidity and mortality despite evidence that West Nile virus strains circulating in those regions are similar to those in North America.
Muscarinic modulation of erg potassium current

We studied modulation of current in human embryonic kidney tsA-201 cells coexpressing rat erg1 channels with M1 muscarinic receptors. Maximal current was inhibited 30% during muscarinic receptor stimulation, with a small positive shift of the midpoint of activation. Inhibition was attenuated by coexpression of the regulator of G-protein signalling RGS2 or of a dominant-negative protein, Gq, but not by N-ethylmaleimide or C3 toxin. Overexpression of a constitutively active form of Gq (but not of G13 or of Gs) abolished the erg current. Hence it is likely that Gq/11, and not Gi/o or G13, mediates muscarinic inhibition. Muscarinic suppression of erg was attenuated by chelating intracellular Ca2+ to < 1 nm free Ca2+ with 20 mm BAPTA in the pipette, but suppression was normal if internal Ca2+ was strongly clamped to a 129 nm free Ca2+ level with a BAPTA buffer and this was combined with numerous other measures to prevent intracellular Ca2+ transients (pentosan polysulphate, preincubation with thapsigargin, and removal of extracellular Ca2+). Hence a minimum amount of Ca2+ was necessary for the inhibition, but a Ca2+ elevation was not. The ATP analogue AMP-PCP did not prevent inhibition. The protein kinase C (PKC) blockers staurosporine and bisindolylmaleimide I did not prevent inhibition, and the PKC-activating phorbol ester PMA did not mimic it. Neither the tyrosine kinase inhibitor genistein nor the tyrosine phosphatase inhibitor dephostatin prevented inhibition by oxotremorine-M. Hence protein kinases are not needed. Experiments with a high concentration of wortmannin were consistent with recovery being partially dependent on PIP2 resynthesis. Wortmannin did not prevent muscarinic inhibition. Our studies of muscarinic inhibition of erg current suggest a role for phospholipase C, but not the classical downstream messengers, such as PKC or a calcium transient.
Detection of botnets using combined host- and network-level information

Bots are coordinated by a command and control (C&C) infrastructure to launch attacks that seriously threaten the Internet services and users. Most botnet-detection approaches function at the network level and require the analysis of packets' payloads, raising privacy concerns and incurring large computational overheads. Moreover, network traffic analysis alone can seldom provide a complete picture of botnets' behavior. By contrast, in-host detection approaches are useful to identify each bot's host-wide behavior, but are susceptible to the host-resident malware if used alone. To address these limitations, we consider both the coordination within a botnet and the malicious behavior each bot exhibits at the host level, and propose a C&C protocol-independent detection framework that combines host- and network-level information for making detection decisions. The framework is shown to be effective in detecting various types of botnets with low false-alarm rates.
The effect of leptin on adipocyte metabolism in leptin-responsive, partially leptin-resistant, and leptin-resistant animals.

We consistently find that peripheral infusions of physiological doses of leptin inhibit lipogenesis in leptin-responsive animals. This study determined which aspect of leptin response was lost in fully and partially leptin-resistant animals. Male Wistar rats consumed a low-fat (LF, 10%) or high-fat (HF, 60%) diet for 3 months to generate diet induced obesity and leptin-resistance, which was confirmed by a bolus i.p. injection of 2.5 mg/kg leptin inhibiting 24 h food intake of only low-fat (LF, 10%) fed rats. Subsequently, rats were infused with 70 μg leptin/d or PBS for 11 days. Metabolic changes were measured in liver, epididymal (EPI), and retroperitoneal (RP) fat pads. Results showed leptin had no effect on liver or adipocyte metabolism of the HF-fed rats. In contrast, LF-fed rats were partially leptin-resistant as demonstrated by unexpected increases in liver and RP fatty acid synthesis (FAS), and increased RP basal glucose oxidation. Subsequently, to obtain data from leptin-responsive animals we conducted the same study in Wistars fed LF diet for 3 weeks. We found the expected decrease in RP fatty acid esterification, glucose oxidation, and inhibition of de novo FAS in both EPI and RP pads. These results confirmed that physiological doses of leptin reduce body fat in leptin-responsive animals by inhibiting lipogenesis. There is no effect in leptin resistant rats, but surprisingly, leptin promotes fat gain in animals progressing from leptin-responsiveness to leptin-resistance. Further studies are needed to investigate why leptin increases adipose mass in partially leptin-resistant models. Supported by NIH Grant DK053903.
Shore‐based recorder of low‐frequency ocean waves

A pressure head on the sea bottom contains a hydraulic filter which attenuates high-frequency signals caused by ordinary gravity waves, and low-frequency signals caused by tides. Maximum response is for frequencies at about one cycle per 1000 sec. A strain-gage transducer converts the filtered pressure fluctuations into electrical signals, which are transmitted to shore through a cable.