bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing students' understanding of the concept of chemical bonding by using activities provided on an interactive website
Authors: Frailich Marcel , Kesner Miri , Hofstein Avi
Published: November 2008

This study investigated the effectiveness of a web‐based learning environment in enhancing 10th grade high‐school students' understanding of the concept of chemical bonding. Two groups participated in this study: an experimental group (N = 161) and a comparison one (N = 93). The teachers in the experimental group were asked to implement four activities taken from a website, all dealing with the concept of chemical bonding. Computer‐based visual models are utilized in all the activities in order to demonstrate bonding and the structure of matter, and are based on student‐centered learning. The study incorporated both quantitative and qualitative research. The quantitative research consisted of achievement questionnaires administered to both the experimental and comparison groups. In contrast, the qualitative research included observations and interviews of students and teachers. Importantly, we found that the experimental group outperformed the comparison group significantly, in the achievement post‐test, which examines students' understanding of the concept of chemical bonding. These results led us to conclude that the web‐based learning activities which integrated visualization tools with active and cooperative learning strategies provided students with opportunities to construct their knowledge regarding the concept of chemical bonding. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 46: 289–310, 2009
Modeling and analysis of a self‐learning worm based on good point set scanning
Authors: Wang Fangwei , Zhang Yunkai , Ma Jianfeng
Published: November 2008

Internet worms can self‐propagate over the Internet, and have caused significant damages to the Internet infrastructure. To speed up the propagating process, the worms need to scan many Internet Protocol (IP) addresses to target vulnerable hosts. However, the distribution of IP addresses is highly non‐uniform, which results in many scans wasted on invulnerable addresses. Inspired by the theory of good point set, this paper proposes a new scanning strategy, referred to as good point set scanning (GPSS), for worms. Experimental results show that GPSS can generate more distinct IP addresses and less unused IP addresses than the permutation scanning. Combined with group distribution, a static optimal GPSS is derived. Since the information cannot be easily collected before a worm is released, a self‐learning worm with GPSS is designed. Such worm can accurately estimate the underlying vulnerable‐host distribution when a sufficient number of IP addresses of infected hosts are collected. We use a modified Analytical Active Worm Propagation (AAWP) to simulate data of Code Red and the performance of different scanning strategies. Experimental results show that once the distribution of vulnerable hosts is accurately estimated, a self‐learning worm can propagate much faster than other worms. Finally, some possible countermeasures are given. Copyright © 2008 John Wiley & Sons, Ltd.
New polymeric candidate reference materials for XRF and LA‐ICP‐MS—development and preliminary characterization
Authors: Mans Christian , Simons Christoph , Hanning Stephanie , Janßen Anton , Alber Dorothea , Radtke Martin , Reinholz Uwe , Bühler Arnd , Kreyenschmidt Martin
Published: November 2008

A set of ten calibration materials based on acrylonitrile‐butadiene‐styrene terpolymer (ABS) containing the elements Br, Pb, Cd, Cr, and Hg was produced in order to control polymer samples in regard to the restriction on the use of certain hazardous substances (RoHS) directive. The materials were produced with respect to the special demands of X‐ray fluorescence analysis (XRF) and inductively coupled plasma mass spectrometry in combination with laser ablation (LA‐ICP‐MS).

The mass fractions of all elements were 0–1500 mg/kg and the materials were produced as granulates and solid discs with a diameter of 40 mm and thicknesses of 1, 2, and 6 mm. It could be shown that the signals measured by XRF strongly depend on the thickness of polymeric samples.

Macroscopic homogeneity was assessed with XRF measuring a total of 180 samples. The microscopic homogeneities were determined for a material with average elemental mass fractions with the aid of synchrotron radiation (SR) µ‐XRF and LA‐ICP‐MS. Sufficient macroscopic and microscopic homogeneities for all elements could be achieved. It was observed that organic additives show a better homogeneity than oxides.

XRF and LA‐ICP‐MS were successfully calibrated with the new materials. Limits of detection were in the range of 0.4–22 mg/kg for XRF and 2.3–26.8 mg/kg for LA‐ICP‐MS. The materials are considered as candidate reference materials (RM) by the Federal Institute of Materials Research and Testing (BAM, Germany). Copyright © 2008 John Wiley & Sons, Ltd.
Europe's changing population in a global context
Authors: Lutz Wolfgang
Published: November 2008

While most analyses of demographic change focus solely on quantitative changes and accompanying predictions for the future, this article combines evidence of population quantity shifts with human capital quality shifts. That is, it examines the demographic debate in light of human capital and education. The author argues that if skilled individuals in a population are the ultimate resource ensuring sustainable development, it is of utmost importance to address declining levels of education. In sum, he advocates large investments in human capital formation as the key to managing the future.
Public versus private old-age pensions in Europe
Authors: Calciano Filippo L. , Tirelli Mario
Published: November 2008

The welfare state and old-age pensions are central pillars in modern societal and economic thought. Doubts about the future sustainability of the national pension system have prompted reforms which must contend with sensitive economic, demographic, social and political issues. This article reviews in depth the role of the state and private actors in pension systems. It suggests wider participation of the private sector in current pension systems coupled with well-considered policy regulation.
Regulation of the stability and transcriptional activity of NFATc4 by ubiquitination
Authors: Fan Yongna , Xie Ping , Zhang Tianpeng , Zhang Hua , Gu Dongfeng , She Mingpeng , Li Huihua
Published: November 2008

MINT‐6798349:

NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti bait coimmunoprecipitation (MI:0006)

MINT‐6798334:

NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti tag coimmunoprecipitation (MI:0007)

MINT‐6798321:

Ubiquitin (uniprotkb:P62988) physically interacts (MI:0218) with NFATc4 (uniprotkb:Q14934) by pull down (MI:0096)
The effect ofapoEgenotype and sex on ApoE plasma concentration is determined by dietary fat in healthy subjects
Authors: Moreno Juan Antonio , Pérez-Jiménez Francisco , Moreno-Luna Rafael , Pérez-Martínez Pablo , Fuentes-Jiménez Francisco , Marín Carmen , Portugal Henri , Lairon Denis , López-Miranda José
Published: November 2008

The interindividual variation in ApoE plasma concentration is considerable, mainly determined byapoEgenotype and sex. However, a large amount of variability remains unexplained by these factors. We have evaluated whether the quantity and quality of dietary fat interacts with theapoEgenotype and sex modifying ApoE plasma levels in young healthy subjects. Eighty-four volunteers (sixty-six apoE3/3, eight apoE4/3 and ten apoE3/2) were subjected to three dietary periods, each lasting 4 weeks. The first was a SFA-enriched diet (38 % fat and 20 % SFA), which was followed by a carbohydrate (CHO)-rich diet (30 % fat, < 10 % SFA and 55 % carbohydrate) or a MUFA-rich diet (38 % fat and 22 % MUFA) following a randomised crossover design.apoE2carriers have the highest ApoE levels, whereasapoE4individuals show the lowest concentration after the SFA, CHO and MUFA diets. Women had significantly higher ApoE concentration than men only after the consumption of the SFA diet. The SFA diet increased the ApoE plasma concentration when compared with the CHO- and MUFA-rich diets in women, but not in men. In women, but not in men, the shift from the SFA- to CHO- or MUFA-rich diets significantly decreased the ApoE concentration in apoE3/2 and apoE3/3 subjects, whereas no differences were observed in women with the apoE4/3 genotype. Sex andapoEgenotype determine ApoE plasma levels; however, this effect is dependent on dietary fat.
Vitamin A equivalency of β-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect
Authors: Van Loo-Bouwman Carolien A. , West Clive E. , van Breemen Richard B. , Zhu Dongwei , Siebelink Els , Versloot Pieter , Hulshof Paul J. M. , van Lieshout Machteld , Russel Frans G. M. , Schaafsma Gertjan , Naber Ton H. J.
Published: November 2008

Data on the vitamin A equivalency of β-carotene in food are inconsistent. We quantified the vitamin A equivalency (μg) of β-carotene in two diets using the dual-isotope dilution technique and the oral–faecal balance technique. A diet-controlled, cross-over intervention study was conducted in twenty-four healthy adults. Each subject followed two diets for 3 weeks each: a diet containing vegetables low in β-carotene with supplemental β-carotene in salad dressing oil (‘oil diet’) and a diet containing vegetables and fruits high in β-carotene (‘mixed diet’). During all 6 weeks, each subject daily consumed a mean of 55 (sd 0·5) μg [13C10]β-carotene and 55 (sd 0·5) μg [13C10]retinyl palmitate in oil capsules. The vitamin A equivalency of β-carotene was calculated as the dose-corrected ratio of [13C5]retinol to [13C10]retinol in serum and from apparent absorption by oral–faecal balance. Isotopic data quantified a vitamin A equivalency of [13C10]β-carotene in oil of 3·4 μg (95 % CI 2·8, 3·9), thus the bio-efficacy of the β-carotene in oil was 28 % in the presence of both diets. However, data from oral–faecal balance estimated vitamin A equivalency as 6:1 μg (95 % CI 4, 7) for β-carotene in the ‘oil diet’. β-Carotene in the ‘oil diet’ had 2·9-fold higher vitamin A equivalency than β-carotene in the ‘mixed diet’. In conclusion, this extrinsic labelling technique cannot measure effects of mixed vegetables and fruits matrices, but can measure precisely the vitamin A equivalency of the β-carotene in oil capsules.
Influence of dietary phytosterols and phytostanols on diastolic blood pressure and the expression of blood pressure regulatory genes in SHRSP and WKY inbred rats
Authors: Chen Qixuan , Gruber Heidi , Swist Eleonora , Pakenham Catherine , Ratnayake Walisundera M. N. , Scoggan Kylie A.
Published: November 2008

The aim of the present study was to determine the impact of increased consumption of phytosterols or phytostanols on blood pressure and renal blood pressure regulatory gene expression in stroke-prone spontaneously hypertensive (SHRSP) and normotensive Wistar–Kyoto (WKY) inbred rats. SHRSP and WKY inbred rats (10/group) were fed a control diet or a diet supplemented with phytosterols or phytostanols (2·0 g/kg diet). After 5 weeks, SHRSP rats demonstrated higher systolic and diastolic blood pressures than WKY inbred rats. SHRSP rats that consumed the phytosterol or phytostanol supplemental diets displayed a 2- or 3-fold respective increase in the diastolic blood pressure than those that consumed the control diet. Angiotensinogen (Agt), angiotensin I-converting enzyme 1 (Ace1), nitric oxide synthase (Nos) 1,Nos3, cyclooxygenase 2 (Cox2) and THUMP domain containing 1 were expressed at higher levels in SHRSP compared with WKY inbred rats.Reninand angiotensin II receptor type 1a were expressed at lower levels in SHRSP than WKY inbred rats. Phytostanol supplementation up-regulated the expression ofAce1andNos3in SHRSP rats. Phytosterol supplementation increased the mRNA levels ofNos1and spondin 1 (Spon1) in SHRSP and WKY inbred rats.Cox2mRNA levels were elevated in both phytosterol- and phytostanol-supplemented SHRSP and WKY inbred rats. Therefore, the increased blood pressure in SHRSP rats may be partly due to altered renal expression of blood pressure regulatory genes. Specifically, up-regulation ofAce1,Nos1,Nos3,Cox2andSpon1were associated with the increased diastolic blood pressure observed in phytosterol- or phytostanol-supplemented SHRSP rats.
Dose-dependent impact of larval Ascaris suum on host body weight in the mouse model
Authors: Lewis R. , Behnke J.M. , Stafford P. , Holland C.V.
Published: November 2008

Ascaris lumbricoides and Ascaris suum are important helminth parasites of humans and pigs, respectively. Although it is now well established that the presence of mature adult worms in the host intestine contributes to significant nutritional morbidity, the impact of larval migratory ascariasis is far less well understood. The development of a mouse model to explore susceptibility and resistance to larval ascariasis in the lungs provided an opportunity to observe the impact of larval migration on host growth during the course of infection. Changes in body weight were monitored in two strains of inbred mice, the susceptible C57BL/6j and the resistant CBA/Ca. Groups of mice received one of four doses: 100, 500, 1000 and 3000 fully embryonated A. suum ova. Infected mice underwent post-mortem on days 6, 7 and 8 post-infection. Control mice received a placebo dose of intubation medium and underwent post-mortem on day 7 post-infection. Mice were weighed pre-infection (day 0) and post-infection on the day of post-mortem. At post-mortem, the lungs of each mouse were removed for enumeration of Ascaris larval burdens by means of the modified Baermann method. Control mice of each strain showed an increase in weight from pre-infection to post-infection day. Within the C57BL/6j strain, mice infected with higher doses of Ascaris eggs experienced a reduction in body weight; for those given 3000 eggs this was on all three post-mortem days, and for those given 1000, on days 7 and 8. For CBA/Ca mice, only mice receiving the 3000 dose demonstrated a reduction in body weight. These findings suggest that larval migratory ascariasis has a significant negative impact upon host growth and that this is related to infective dose and larval burden.
UTILITARIAN AGGREGATION
Authors: Hardin Russell
Published: November 2008

There can be no relevant cardinal assessment of the welfares of individuals that would allow traditional comparisons of average and total welfare of whole societies to be made. Given that cardinally additive welfare measures are unavailable, I work out some of the implications of an ordinal utilitarian analysis of international distributional issues. I first address the general problem of utilitarian comparisons between aggregates, then the nature of ordinal transfers between groups or nations, and then the complications that population growth in impoverished nations entails for such comparisons. I conclude with remarks on the difficulties and the benefits of thinking ordinally in general.
UP AND DOWN WITH AGGREGATION
Authors: Hooker Brad
Published: November 2008

This paper starts by addressing some objections to the very idea of aggregate social good. The paper goes on to review the case for letting aggregate social good be not only morally relevant but also sometimes morally decisive. Then the paper surveys objections to letting aggregate social good determine personal or political decisions. The paper goes on to argue against the idea that aggregate good is sensitive to desert and the idea that aggregate good should be construed as incorporating agent-relativity.
AGGREGATION, ALLOCATING SCARCE RESOURCES, AND THE DISABLED
Authors: Kamm F. M.
Published: November 2008

In this article, I first compare positions I have taken in the past and those taken by Peter Singer on how the allocation of life-saving resources should be affected by (1) the aggregation of expected quality of life, quantity of life, and need, (2) both within the life of a person (intrapersonal aggregation) and across persons (interpersonal aggregation). I then reexamine the specific issue of whether and why differences in expected years of life and quality of life that a scarce resource can provide a disabled and a nondisabled person should affect our allocation decisions. I attend to how the use of the veil of ignorance bears on this issue and also how the conclusions I reach differ in certain ways from my past positions.
BENEFITS, HOLISM, AND THE AGGREGATION OF VALUE
Authors: McNaughton David , Rawling Piers
Published: November 2008

We reject Moorean holism about value—the view that the value of the whole does not equal the sum of the values of its parts. We propose an alternative aggregative holism according to which the value of a state of affairs is the sum of the values of its constituent states. But these constituents must be evaluated in situ.

We also argue that, in addition to value tout court, there are benefits that can go to individuals—where the value of a state of affairs need not equal the sum of the benefits it supplies. To deny this claim is to deny, among other things, the possibility of even raising distributional concerns, or that of stating egoism in a coherent fashion. And denying these possibilities is implausible. But once benefits are in the picture, there is, pace certain forms of consequentialism, pressure to acknowledge that we can have extra reason to pursue them beyond considerations of the effect of such pursuit on the general good.

We conclude by applying these thoughts to, first, the claim that Pareto-optimality is necessary for maximal value (we argue that this thesis is false); and, second, Parfit's ‘repugnant conclusion’ (we use this conclusion to bolster our claim that value need not be the sum of benefits: if value were always the sum of benefits, the repugnant conclusion would follow; the repugnant conclusion is false; therefore value is not always the sum of benefits).
Developments in the Theory and Practice of Cognitive and Behavioural Therapies
Authors: Taylor John L. , Steel Craig
Published: November 2008

In 1993 Behavioural and Cognitive Psychotherapy published a supplement edited by Ann Hackmann with the title “Behavioural and Cognitive Psychotherapies: Past History, Current Applications and Future Registration Issues”. This was the journal's first ever supplement and it provided an overview of the state of behavioural and cognitive psychotherapies at that time. It was intended to provide a context for discussions concerning the future of the field, and as Paul Salkovskis said in his editorial, “[the supplement]. . .will be an important reference source for years to come.”
ON THE NUMBER OF SIGN CHANGES OF HECKE EIGENVALUES OF NEWFORMS
Authors: KOHNEN WINFRIED , LAU YUK-KAM , SHPARLINSKI IGOR E.
Published: November 2008

We show that, for every x exceeding some explicit bound depending only on k and N, there are at least C(k,N)x/log 17x positive and negative coefficients a(n) with n≤x in the Fourier expansion of any non-zero cuspidal Hecke eigenform of even integral weight k≥2 and squarefree level N that is a newform, where C(k,N) depends only on k and N. From this we deduce the existence of a sign change in a short interval.
AN ALMOST EVERYWHERE VERSION OF SMÍTAL’S ORDER–CHAOS DICHOTOMY FOR INTERVAL MAPS
Authors: BARRIO BLAYA ALEJO , JIMÉNEZ LÓPEZ VÍCTOR
Published: November 2008

We prove that iff:I=[0,1]→Iis aC3-map with negative Schwarzian derivative, nonflat critical points and without wild attractors, then exactly one of the following alternatives must occur: (i) R(f) has full Lebesgue measureλ; (ii) bothS(f) andScramb(f) have positive measure. HereR(f),S(f), andScramb(f) respectively stand for the set of approximately periodic points off, the set of sensitive points to the initial conditions off, and the two-dimensional set of points (x,y) such that {x,y} is a scrambled set forf. Also, we show that iffis piecewise monotone and has no wandering intervals, then eitherλ(R(f))=1 orλ(S(f))>0, and provide examples of mapsg,hof this type satisfyingS(g)=S(h)=Isuch that, on the one hand,λ(R(g))=0 andλ2(Scramb(g))=0 , and, on the other hand,λ(R(h))=1 .
Manipulation of dendritic cell functions by human cytomegalovirus
Authors: Sinclair John
Published: November 2008

Dendritic cells are the most potent antigen-presenting cells of the mammalian immune system and are central to the initiation and maintenance of the adaptive immune response. They are crucial for the presentation of antigen to T cells and B cells, as well as the induction of chemokines and proinflammatory cytokines, which orchestrate the balance of the cell-mediated (Th1) and antibody (Th2) response. This ability of dendritic cells to present antigen and release chemokines and cytokines also bridges the innate and adaptive immune responses by driving T cell activation. These cells thus possess key immunological functions that make them the front line of defence for the targeting and clearance of any invading pathogen and, as such, they underpin the host immune response to infection. For efficient infection, invading pathogens often need to overcome these sentinel immune functions. It is therefore not surprising that pathogens have evolved numerous mechanisms to target dendritic cell functions directly or indirectly during infection, and at least one herpesvirus – human cytomegalovirus – has evolved a life cycle that hijacks dendritic cells for its long-term persistence in the infected host.
Quickly erupted volcanic sections of the Steens Basalt, Columbia River Basalt Group: Secular variation, tectonic rotation, and the Steens Mountain reversal
Authors: Jarboe Nicholas A. , Coe Robert S. , Renne Paul R. , Glen Jonathan M. G. , Mankinen Edward A.
Published: November 2008

The Steens Basalt, now considered part of the Columbia River Basalt Group (CRBG), contains the earliest eruptions of this magmatic episode. Lava flows of the Steens Basalt cover about 50,000 km2 of the Oregon Plateau in sections up to 1000 m thick. The large number of continuously exposed, quickly erupted lava flows (some sections contain over 200 flows) allows for small loops in the magnetic field direction paths to be detected. For volcanic rocks, this detail and fidelity are rarely found outside of the Holocene and yield estimates of eruption durations at our four sections of ∼2.5 ka for 260 m at Pueblo Mountains, 0.5 to 1.5 ka for 190 m at Summit Springs, 1–3 ka for 170 m at North Mickey, and ∼3 ka for 160 m at Guano Rim. That only one reversal of the geomagnetic field occurred during the eruption of the Steens Basalt (the Steens reversal at approximately 16.6 Ma) is supported by comparing 40Ar/39Ar ages and magnetic polarities to the geomagnetic polarity timescale. At Summit Springs two 40Ar/39Ar ages from normal polarity flows (16.72 ± ± 0.29 Ma (16.61) and 16.92 ± ± 0.52 Ma (16.82); ± ± equals 2σ error) place their eruptions after the Steens reversal, while at Pueblo Mountains an 40Ar/39Ar age of 16.72 ± ± 0.21 Ma (16.61) from a reverse polarity flow places its eruption before the Steens reversal. Paleomagnetic field directions yielded 50 nontransitional directional‐group poles which, combined with 26 from Steens Mountain, provide a paleomagnetic pole for the Oregon Plateau of 85.7°N, 318.4°E, K = 15.1, A95 = 4.3. Comparison of this new pole with a reference pole derived from CRBG flows from eastern Washington and a synthetic reference pole for North America derived from global data implies relative clockwise rotation of the Oregon Plateau of 7.4 ± 5.0° or 14.5 ± 5.4°, respectively, probably due to northward decreasing extension of the basin and range.
Discovery of a transient radiation belt at Saturn
Authors: Roussos E. , Krupp N. , Armstrong T. P. , Paranicas C. , Mitchell D. G. , Krimigis S. M. , Jones G. H. , Dialynas K. , Sergis N. , Hamilton D. C.
Published: November 2008

Radiation belts have been detected in situ at five planets. Only at Earth however has any variability in their intensity been heretofore observed, in indirect response to solar eruptions and high altitude nuclear explosions. The Cassini spacecraft's MIMI/LEMMS instrument has now detected systematic radiation belt variability elsewhere. We report three sudden increases in energetic ion intensity around Saturn, in the vicinity of the moons Dione and Tethys, each lasting for several weeks, in response to interplanetary events caused by solar eruptions. However, the intensifications, which could create temporary satellite atmospheres at the aforementioned moons, were sharply restricted outside the orbit of Tethys. Unlike Earth, Saturn has almost unchanging inner ion radiation belts: due to Saturn's near‐symmetrical magnetic field, Tethys and Dione inhibit inward radial transport of energetic ions, shielding the planet's main, inner radiation belt from solar wind influences.
Geothermal He and CO2 variations at Changbaishan intra‐plate volcano (NE China) and the nature of the sub‐continental lithospheric mantle
Authors: Hahm D. , Hilton D. R. , Cho M. , Wei H. , Kim K.‐R.
Published: November 2008

We report new He and CO2 data for geothermal fluids from Changbaishan Volcano located on the border of China and North Korea. Helium isotope ratios reach a maximum of 5.4 RA (where RA = 3He/4He in air) whereas carbon isotope values (δ13C) fall between −2 and −7 ‰ (vs. PDB). The ratio of CO2/3He varies between 0.5–7.1 (×109) for gas samples but is considerably higher (∼1012) in waters. The combined He‐CO2 systematics reveal the clear imprint of a dominant subducted slab contribution to the total CO2 inventory. We conclude that these geothermal volatiles originate from the sub‐continental lithospheric mantle (SCLM) in NE China and represent ancient fluids captured by prior metasomatic events.
Reduction of electron temperature in low‐latitude ionosphere at 600 km before and after large earthquakes
Authors: Oyama Koh‐Ichiro , Kakinami Yoshihiro , Liu Jann‐Yenq , Kamogawa Masashi , Kodama Tetsuya
Published: November 2008

We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that Te around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80–120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F2 peak frequency, foF2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E–130°E are used together with electron density(Ne), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI Te/Ne and ionosonde foF2/h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.
Perpendicular electric field in two‐dimensional electron phase‐holes: A parameter study
Authors: Lu Q. M. , Lembege B. , Tao J. B. , Wang S.
Published: November 2008

Previous multi‐dimensional particle simulations have shown that electron phase‐holes can be formed during the nonlinear evolution of bi‐stream instability. In these holes, the parallel cut of the parallel electric field (E∥) has bipolar structures while the parallel cut of the perpendicular electric field (E⊥) has unipolar structures. In this paper, two‐dimensional (2D) electrostatic particle‐in‐cell simulations are performed to investigate the evolution of E⊥ in such electron holes for different plasma conditions, and the generation mechanism of the unipolar structures of E⊥ is also discussed. The electrons trapped in electron holes bounce in the parallel direction, which leads to transverse instability (Muschietti et al., 2000). At the same time, they gyrate in the background magnetic field, which tends to stabilize electron holes. In this way, the trapped electrons are forced to accumulate locally, and the charge density has variations along the perpendicular direction inside the electron holes. The balance between these two effects leads to the following results: in weakly magnetized plasma (Ωe < ωpe, but Ωe is comparable to ωpe. Where Ωe and ωpe are the electron cyclotron frequency and electron plasma frequency, respectively), electron holes have two‐dimensional structures (isolated along both the parallel and perpendicular directions). Within such holes the parallel cut of E⊥ has unipolar structures. In strongly magnetized plasma (Ωe > ωpe), electron holes have one‐dimensional structures along the direction perpendicular to the background magnetic field within which a series of islands (with alternate positive and negative E⊥) develop because of the variations of the charge density along the perpendicular direction. Therefore one recovers that a parallel cut of E⊥ has unipolar structures at the location of the holes. Present results show that the unipolar structure of E⊥ in electron holes is attributed to the balance between the electron transverse instability and the stabilization of the background magnetic field. The unipolar structures of E⊥ in electron holes last for hundreds to thousands of electron plasma periods. They are destroyed and the streaked structures are formed in the whole simulation domain after the electrostatic whistler waves are excited and have sufficiently large amplitude. The influences of the initial perpendicular thermal velocity of electrons (via temperature anisotropy) and the drift speed of electron beam on the structures of E⊥ are also analyzed in details. At last, the relevance between our simulation results and the unipolar structures of the parallel cut of E⊥ observed in the auroral region is discussed.
Partitioning of iron between perovskite/postperovskite and ferropericlase in the lower mantle
Authors: Sinmyo Ryosuke , Hirose Kei , Nishio‐Hamane Daisuke , Seto Yusuke , Fujino Kiyoshi , Sata Nagayoshi , Ohishi Yasuo
Published: November 2008

The Fe2+‐Mg distribution coefficients (KD) between perovskite/postperovskite and ferropericlase were determined in a (Mg0.9Fe0.1)2SiO4 bulk composition. High‐pressure and high‐temperature experiments were carried out between 36 and 128 GPa and 1760–2170 K in a laser‐heated diamond anvil cell (LHDAC). Chemical analyses were made on recovered samples with transmission electron microscope (TEM) and field‐emission‐type scanning electron microscope (FE‐SEM). All the samples exhibited a strong heterogeneity in iron content caused by relatively large temperature gradient during laser‐heating, being depleted at the center of the hot spot and enriched at the margin. The KD values measured from coexisting perovskite/postperovskite and ferropericlase showed apparently very large variation in each sample, which could be the source of considerable discrepancy among previous measurements of KD using the LHDAC techniques. Nevertheless, the data obtained from a specific portion of the sample that retained the original bulk composition may represent the equilibrium partitioning. Present results demonstrate that the iron partitioning between perovskite/postperovskite and ferropericlase changes little at a given temperature throughout the lower mantle pressures. Both electronic transition of iron and postperovskite phase transition have small effects on iron partitioning.
Multidecadal variability of Atlantic hurricane activity: 1851–2007
Authors: Chylek Petr , Lesins Glen
Published: November 2008

An analysis of Atlantic hurricane data (HURDAT), using a hurricane activity index that integrates over hurricane numbers, durations, and strengths during the years 1851–2007, suggests a quasi‐periodic behavior with a period around 60 years superimposed upon a linearly increasing background. The linearly increasing background is significantly reduced or removed when various corrections were applied for hurricane undercounting in the early portion of the record. The periodic‐like behavior is persistent in uncorrected HURDAT data as well as in data corrected for possible missing storms. The record contains two complete cycles: 1860–1920 and 1920–1980. The 2004 and 2005 hurricane seasons were unusual in that two intense hurricane seasons occurred in consecutive years. The probability for this happening in any given year is estimated to be less then 1%. Comparing the last 28 years (1980–2007) with the preceding 28 years (1953–1980), we find a modest increase in the number of minor hurricanes (category 1 and 2); however, we find no increase in the number of major hurricanes (category 3–5). The hurricane activity index is found to be highly correlated with the Atlantic Multidecadal Mode (AMM). If there is an increase in hurricane activity connected to a greenhouse gas induced global warming, it is currently obscured by the 60 year quasi‐periodic cycle.
Analytical studies on transient groundwater flow induced by land reclamation
Authors: Hu Litang , Jiao Jiu Jimmy , Guo Haipeng
Published: November 2008

In many coastal areas, land has been reclaimed by dumping fill materials into the sea. Land reclamation may have a significant effect on groundwater regimes, especially when the reclamation is at large scale. Analytical studies on the impact of land reclamation on steady‐state ground water flow conditions were conducted previously, but transient analytical solutions are not yet available. Transient analytical solutions are derived to illustrate the temporal change of groundwater systems in response to land reclamation using two hypothetical models: a hillside aquifer and an oceanic elongated island. The analytical solutions show that when time is short, the water level in the reclaimed area increases significantly after reclamation while that in the original aquifer remains almost unchanged. When time is great, the change of water level in the reclaimed site becomes small but the increase of water level propagates into the original aquifer. For the specific parameters and aquifer geometry used in the examples, it takes at least over 100 years for the whole system to approach a new equilibrium. The island example demonstrates that land reclamation on one side of the island will eventually modify the groundwater regimes over the entire island, including the water level, water divide, and submarine groundwater discharge. The degree of the modification of the groundwater system and the time required for the system to approach a new equilibrium depend mainly on the hydraulic conductivity and storativity of the fill materials and the reclamation length. It is suggested that for a large reclamation project, the response of the groundwater regime to reclamation should be studied in detail to evaluate the long‐term change of the flow system and the consequent environmental and engineering impacts.
New fungal sources for α-L-Rhamnosidase: an important enzyme used in the synthesis of drugs and drug precursors
Authors: Yadav Vinita , Yadav Kapil Deo Singh
Published: November 2008

Two fungal strains were isolated and tentatively identified as Penicillium VY and Aspergillus VY. All the isolated species show the maximum production on third day in a liquid culture media. The pH optimum was found to be 10.0 for Penicillium VY and 11.0 for Aspergillus VY. The temperature optima were 50ºC in both the cases. The enzyme produced by Penicillium VY was found to be stable in the pH range 3.0-7.0 and 3.0–6.0 in case of Aspergillus VY. The enzyme does not loose activity up to 40º C in case of Penicillium VY and 40ºC in case of Aspergillus VY if exposed for 1 h.
Effect of Fenofibrate on Adiponectin and Inflammatory Biomarkers in Metabolic Syndrome Patients
Authors: Rosenson Robert S.
Published: November 2008

Adiponectin is an adipose‐secreted hormone with anti‐inflammatory properties mediated by inhibition of nuclear factor‐κB (NF‐κB) signaling. This study investigates whether fenofibrate alters adiponectin levels in patients with hypertriglyceridemia and the metabolic syndrome, and examines the association of adiponectin with circulating inflammatory markers and whole blood cytokine production. The effects of fenofibrate (160 mg/day) on adiponectin and other inflammatory markers were investigated in a 12‐week randomized, placebo‐controlled trial in 55 patients with hypertriglyceridemia (plasma triglycerides ≥1.7 mmol/l and <6.8 mmol/l), central obesity and other characteristics of the metabolic syndrome who were not receiving lipid‐altering therapies. In the fenofibrate group, adiponectin levels increased from 4.10 to 4.50 µg/ml (+7.7%); in the placebo group, adiponectin levels increased by 1.8%; (P = 0.0005). In multivariate models including age, gender, and waist circumference, there were inverse correlations between changes in adiponectin and vascular cell adhesion molecule‐1 (VCAM‐1) (r = −0.54, P < 0.0001) and intercellular adhesion molecule‐1 (ICAM‐1) (r = −0.57, P < 0.0001), and C‐reactive protein (CRP) (r = −0.40, P = 0.0041); lipopolysaccharide (LPS)‐stimulated production of tumor necrosis factor‐α (TNF‐α) (r = −0.30, P = 0.035), interleukin (IL)‐1β (r = −0.44, P = 0.0016), monocyte chemotactic protein‐1 (MCP‐1) (r = −0.46, P = 0.001), and macrophage inflammatory protein‐1α (MIP‐1α) (r = −0.45, P = 0.0012). Fenofibrate (160 mg/day) raised adiponectin levels in patients with hypertriglyceridemia and the metabolic syndrome. Changes in adiponectin were significantly and inversely associated with changes in multiple inflammatory markers. These data suggest that adiponectin may contribute to the anti‐inflammatory effects of fenofibrate.
Americans Travelling to Europe: A New Perspective Based on Persistence
Authors: Gil-Alana Luis A.
Published: November 2008

This paper deals with the analysis of American citizens travelling to Europe, examining the degree of persistence of the series and testing whether shocks are of a transitory or of a permanent nature. For this purpose, we use a methodology based on fractional integration, including seasonal autoregressions to describe the short-run (seasonal) dynamics underlying the series. We show that the series is highly persistent with an order of integration slightly below one. Moreover, the existence of a unit root cannot be rejected at standard significance levels. In the final part of the paper, we also examine the existence of a structural break, comparing the degree of persistence before and after the September 11th attacks. The results indicate that there has been a substantial reduction in the degree of persistence after the break in 2001.
Determinants of Demand for Exports of Tourism: An Unobserved Component Model
Authors: Algieri Bernardina , Kanellopoulou Stella
Published: November 2008

The present paper analyses the dynamic behaviours of the main determinants of tourism demand for France, Greece, Spain and Australia. In addition to the traditional variables affecting the demand for exports of tourism, namely price and foreign income, an unobserved component in the form of time varying trend enters the tourism equations to capture underlying competitiveness. The structural modelling approach within an error correction framework allows us to isolate the different sources of tourism fluctuations and to better assess the contribution of each set of variables to export flows. The findings confirm that stochastic trends are present as result of consumer tastes, technical change and other exogenous factors driving tourism flows, and that a failure to account for these trends will lead to biased estimates of long-run price and income elasticities.
N/I buffer layer for substrate microcrystalline thin film silicon solar cell
Authors: Söderström T. , Haug F.-J. , Terrazzoni-Daudrix V. , Niquille X. , Python M. , Ballif C.
Published: November 2008

The influence of the substrate surface morphology on the performance of microcrystalline silicon solar cells in the substrate or n-i-p (nip) configuration is studied in this paper. The experiments are carried out on glass substrates coated with naturally textured films of ZnO deposited by low pressure chemical vapor deposition which serves as backcontact and as template for the light trapping texture. The film surface morphology can be modified with a plasma treatment which smoothens the V-shaped valleys to a more U-shaped form. We investigate, first, the influence of different substrates morphologies on the performance of microcrystalline (μc-Si:H) thin film silicon solar cells deposited by very high frequency plasma enhanced chemical vapor deposition. The V-shaped morphologies are found to have strong light trapping capabilities but to be detrimental for the μc-Si:H material growth and lead to degraded open circuit voltage (Voc) and fill factor (FF) of the solar cells. Hence, in Sec. III B, we introduce a buffer layer with a higher amorphous fraction between the n doped and intrinsic layer. Our study reveals that the buffer layer limits the formation of voids and porous areas in the μc-Si:H material on substrates with strong light trapping capabilities. Indeed, this layer mitigates Voc and FF losses which enhances the performance of the μc-Si:H solar cell. Finally, by applying our findings, we report an efficiency of 9% for a nip μc-Si:H thin film silicon cell with a thickness of only 1.2 μm.
Low field giant magnetoresistance in coupled elliptical rings
Authors: Jain S. , Adeyeye A. O.
Published: November 2008

The giant magnetoresistance response of ellipse shaped Co(10 nm)/Cu(8 nm)/Ni80Fe20(10 nm)/Cu(2 nm) rings magnetostatically coupled to external magnetic elements has been systematically investigated. Magnetoresistance responses at low field show distinct states when the field is cycled through various intermediate magnetization states of Ni80Fe20 and Co layers. Due to strong magnetostatic coupling between the ring and the external magnetic elements, these metastable intermediate states were not observed when the field is cycled through saturation. We have also investigated the temperature dependence of magnetization behavior of these rings. Our experimental results are in good agreement with micromagnetic simulations.
Demonstration of detuning and wavebreaking effects on Raman amplification efficiency in plasma
Authors: Yampolsky N. A. , Fisch N. J. , Malkin V. M. , Valeo E. J. , Lindberg R. , Wurtele J. , Ren J. , Li S. , Morozov A. , Suckewer S.
Published: November 2008

A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short laser pulses might, under ideal conditions, convert as much as 90% of the pump energy to the seed pulse. While the theoretical highest possible efficiency of this scheme has not yet been achieved, larger efficiencies than ever before obtained experimentally (6.4%) are now being reported, and these efficiencies are accompanied by strong pulse compression. Based on these recent extensive experiments, it is now possible to deduce that the experimentally realized efficiency of the amplifier is likely constrained by two factors, namely the pump chirp and the plasma wavebreaking, and that these experimental observations may likely involve favorable compensation between the chirp of the laser and the density variation of the mediating plasma. Several methods for further improvement of the amplifier efficiency in current experiments are suggested.
Origin of unusual rapid oxidation process for ultrathin oxidation (<2 nm) of silicon
Authors: Cui H. , Wang C. X. , Yang G. W. , Jiang D.
Published: November 2008

We propose a kinetic model to reveal the origin of unusual rapid oxidation behavior for the ultrathin (<2 nm) oxidation of silicon demonstrated by [Enta et al., Appl. Phys. Lett. 92, 012110 (2008)] by considering the space-charge drift of O ions and the intrinsic concentration gradient diffusion of residual O ions that dominate the initial rapid oxidation process following the slow oxidation state, respectively. Importantly, the present model well describes the whole experiment data with different temperatures and pressures and diffusion activation energies for two regimes attained by our model, which coincides with the reported experiment data and theory calculation.
Smiling Reduces Masculinity: Principal Component Analysis Applied to Facial Images
Authors: Kawamura Satoru , Komori Masashi , Miyamoto Yusuke
Published: November 2008

We examined the effect of facial expression on the assignment of gender to facial images. A computational analysis of the facial images was applied to examine whether physical aspects of the face itself induced this effect. Thirty-six observers rated the degree of masculinity of the faces of 48 men, and the degree of femininity of the faces of 48 women. Half of the faces had a neutral facial expression, and the other half was smiling. Smiling significantly reduced the perceived masculinity of men's faces, especially for male observers, whereas no effect of smiling on femininity ratings was obtained for women's faces. A principal component analysis was conducted on the matrix of pixel luminance values for each facial image × all the images. The third principle component explained a relatively high proportion of the variance of both facial expressions and gender of face. These results suggest that the effect of smiling on the assignment of gender is caused, at least in part, by the physical relationship between facial expression and face gender.
The Effect of Horizontal versus Vertical Task Presentation on Children's Performance in Coordinate Tasks
Authors: Worsfold Naomi , Davis Alyson , De Bruyn Bart
Published: November 2008

Empirical work on children's ability to understand spatial coordinates has focused on the factors that increase children's proficiency. When interpreting performance, it should be considered that presenting a coordinate task on a horizontal surface might constrain the responses that children make because some target positions are further away from the child than others. Vertical task presentation removes this constraint. Children aged 3 to 9 years were presented with an interpretative coordinate task administered on a touchscreen, presented in an egocentric-vertical position or egocentric-horizontal position. The results show that for 5- to 7-year-old children vertical presentation led to far more correct responses than horizontal presentation. Analysis of the children's errors suggests that this may be due to the fact that vertical presentation suppresses children's bias towards responding in relation to one rather than both coordinates. Taken together these findings contribute to understanding why children's performance in xy coordination tasks is highly contextually sensitive.
Biological Motion Alters Coherent Motion Perception
Authors: Fujimoto Kiyoshi , Yagi Akihiro
Published: November 2008

When a movie presents a person walking, the background appears to move in the direction opposite to the person's gait. This study verified this backscroll illusion by presenting a point-light walker against a background of a random-dot cinematogram (RDC). The RDC consisted of some signal dots moving coherently either leftward or rightward among other noise dots moving randomly. The method of constant stimuli was used to vary the RDC in motion coherence from trial to trial by manipulating the direction and percentage of the signal dots. Six observers judged the perceived direction of coherent motion in a two-alternative forced-choice procedure. Response rates for coherent motion perception in the direction opposite to walking were evaluated as a function of motion coherence. The results showed that the psychometric function shifted toward the direction determined by a bias in the opposite direction to the walker. The mean threshold was about half as high as that in a control condition in which the positions of the point-lights were scrambled to impair the recognition of the walker. The results demonstrate that biological motion noticeably affects the appearance of motion coherence in the background.