bluuebunny/crossref_metadata_2025 huggingface dataset:
Life on the edge – to which degree does phreatic water sustain vegetation in the periphery of the Taklamakan Desert?
Authors: Bruelheide Helge , Vonlanthen Beatrix , Jandt Ute , Thomas Frank M. , Foetzki Andrea , Gries Dirk , Wang Gang , Zhang Ximing , Runge Michael
Published: September 2009

Questions: Do the vegetation‐specific patterns in the forelands of river oases of the Taklamakan Desert provide clues to the degree to which a vegetation type depends on unsaturated soil moisture, brought about by extensive floodings, or phreatic water?

Location: Foreland of the Qira oasis on the southern rim of the Taklamakan Desert, Xinjiang Uygur Autonomous Region, China.

Methods: A vegetation map was prepared using a SPOT satellite image and ground truthing. Measurements of soil water contents were obtained from a flooding experiment and transformed into water potentials. Sum excedance values were calculated as the percentage of days on which different thresholds of soil water potentials were transgressed. Groundwater depth was mapped by drilling 30 groundwater holes and extrapolating the distances to the whole study area.

Results: The vegetation was characterized by only six dominant or codominant species: Alhagi sparsifolia, Karelinia caspia, Populus euphratica, Tamarix ramosissima, Calligonum caput‐medusae and Phragmites australis. The vegetation patterns encountered lacked any linear features typical of phreatophytes, thus not allowing direct conclusions on the type of the sustaining water sources. Soil water potentials never transgressed a threshold of pF 5 (−10 MPa) in horizons above the capillary fringe during periods without inundation, thus representing water not accessible for plants. Depth to the groundwater ranged between 2.3 and 17.5 m among plots and varied between 1.7 and 8.0 m within a plot owing to dune relief. The seven main vegetation types showed distinct niches of groundwater depths, corresponding to the observed concentric arrangement of vegetation types around the oasis.

Conclusions: Inundation by flooding and unsaturated soil moisture are irrelevant for the foreland vegetation water supply. Although distances to the groundwater table can reach about 20 m, which is exceptionally large for phreatophytes, groundwater is the only water source for all vegetation types in the oasis foreland. In consequence, successful maintenance of oasis foreland vegetation will crucially depend on providing non‐declining ground water tables.
The post‐partum mid‐upper arm circumference of adolescents is reduced by pregnancy in rural Nepal
Authors: Katz Joanne , Khatry Subarna K. , LeClerq Steven C. , West Keith P. , Christian Parul
Published: September 2009

The purpose of this study was to examine whether changes in the mid‐upper arm circumference (MUAC) in pregnancy and early post‐partum varied by maternal age. The MUAC of 3359 nulliparous pregnant women ≤25 years of age in rural Nepal was measured in early pregnancy and at 3 months post‐delivery of a live‐born infant. Regression was used to model the change in MUAC and prevalence of MUAC < 20 cm by maternal age, adjusted for confounders. A total of 5.2% of the pregnant women were under 16 years of age. The prevalence of MUAC measurements <20 cm was 11.3% in early pregnancy and did not differ by maternal age. The prevalence of low MUAC was 17.7% at post‐partum, but those <16 years of age had a significantly higher prevalence of low post‐partum MUAC [odds ratio: 2.47, 95% confidence interval (CI) 1.49, 4.10] compared with women 20–25 years of age, adjusted for maternal literacy, caste, meat consumption in early pregnancy and timing of measurements. All women reduced their MUAC from early pregnancy through post‐partum. The adjusted loss of the MUAC among those under 16 years of age was 0.97 cm (95% CI: −1.33, −0.60), compared with 0.40 cm (95% CI: −0.70, −0.10) among women 20–25 years of age. In an energy‐restricted environment, girls under 16 years contributed to a half centimetre more loss of MUAC than older women of the same parity. Such a loss of fat, muscle or both may put younger women and their breastfed offspring at greater risk of other adverse health and nutritional outcomes.
The role of parents' romantic relationship warmth and hostility in child feeding practices and children's eating behaviours
Authors: Haycraft Emma , Blissett Jackie
Published: September 2009

This research examined the associations between parents' reports of the quality of their romantic relationships with their partner/spouse, their feeding interactions with their children, and their children's eating behaviours. One hundred and fifty‐six married/cohabiting mothers of young children completed self‐report measures of their romantic relationship quality, child feeding practices and children's eating behaviours. Reports of a less warm, more hostile romantic relationship were associated with children's less adaptive eating behaviours. More hostile relationship quality was also related to greater restriction of their children's food intake. The quality of parents' romantic relationships is associated with parental feeding practices and children's eating behaviours. Further work should examine the emotional tone of mealtimes in order to discover whether this may be the mechanism of the relationship.
Subcritical Crack Growth Behavior of A Perovskite‐Type Oxygen Transport Ceramic Membrane
Authors: Nagabhushana Nagendra , Nithyanantham Thangamani , Bandopadhyay Sukumar , Zhang Jing
Published: September 2009

We herein report subcritical crack growth (SCG) studies of La0.2Sr0.8Fe0.8Cr0.2O3−δ (LSFCO) perovskite membranes as oxygen transport membranes (OTM). Two sample batches of perovskite were tested to investigate the effect of temperature, specific chemical environments, and loading rate on flexure strengths, using four‐point bend tests. The first batch was examined at room temperature in air. The second batch was soaked in an N2/air atmosphere at 1000°C. Stress rates varied approximately from 0.2 to 90 MPa/s. The strength–probability–time diagram is constructed for design proposes. Flexural strength data indicate that the examined OTM material showed little susceptibility to SCG at room temperature in air. However, the sample is susceptible to SCG in an N2/air environment at 1000°C. Also, the experiments demonstrate flexural‐strength rate dependency, with strength increasing with the stress rate. The observed phenomena are explained by the decomposition and microstructural transitions in the perovskite.
Towards Cost‐effective Strategies for Treatment of Chronic Kidney Disease‐Mineral and Bone Disorder in Japan
Authors: Komaba Hirotaka , Moriwaki Kensuke , Kamae Isao , Fukagawa Masafumi
Published: September 2009

There is a growing interest worldwide in making a more effective and efficient use of limited health care resources. Dialysis treatment in Japan and other countries is being confronted with increasing expenditure due to an aging population, coverage of new medical technologies, and an increase in the dialysis population. Chronic kidney disease–mineral and bone disorder (CKD‐MBD) is an important issue related to the increased expenditure among dialysis patients because it is one of the main causes of morbidity and mortality, and results in a high economic burden. In recent years, several economic analyses on the treatment of CKD‐MBD have been reported from Western countries. Given the longer dialysis vintage of Japanese patients, it is very important to conduct economic evaluation from a long‐term viewpoint using clinical data on Japanese patients. This article reviews the recent literature on economic evaluation of CKD‐MBD treatments and discusses the road ahead for cost‐effectiveness analysis in Japanese dialysis patients with CKD‐MBD.
Can Cinacalcet Replace Parathyroid Intervention in Severe Secondary Hyperparathyroidism?
Authors: Kakuta Takatoshi , Tanaka Reika , Kanai Genta , Sawaya Asako , Hirukawa Takashi , Sato Atsuhiro , Saito Akira
Published: September 2009

A 6‐month observational study was conducted in 61 patients (33 men and 28 women, mean age 54.8 ± 12.4 years) treated with cinacalcet in whom parathyroid intervention was indicated. Thirty‐seven patients had baseline intact parathyroid hormone (iPTH) levels of >500 pg/mL, but only five still had levels this high after 6‐month cinacalcet therapy. No patients had phosphorus (P), calcium (Ca), or iPTH levels within the target range at baseline, but six patients (9.8%) reached all three target ranges after treatment. The stratum with many patients who had 2–4 enlarged parathyroid glands shifted toward the low PTH groups (iPTH < 300 pg/mL) with treatment. There was less of a tendency for patients with more enlarged glands, that is, 10 mm or larger at baseline, to have a higher PTH level after cinacalcet treatment. There was no significant difference in the total volume of parathyroid glands after treatment, since some glands enlarged while others shrank. These findings indicate cinacalcet to be a potentially useful treatment. Our results suggest that 80% of cases indicated for parathyroid intervention could avoid such interventional therapies with cinacalcet administration. However, the variability in the gland‐shrinking effect of cinacalcet on parathyroid glands merits further study.
Toward an Understanding of the Online Consumer's Risky Behavior and Protection Practices
Authors: MILNE GEORGE R. , LABRECQUE LAUREN I. , CROMER CORY
Published: September 2009

This research draws upon protection motivation theory and social cognitive theory to investigate the extent to which the level of perceived threat and likelihood of threat along with online self‐efficacy affect online behaviors. This article contributes to the literature by investigating a wide range of risky and protective behaviors and examining the role of online self‐efficacy with a national online survey of 449 nonstudent respondents. Results show that both self‐efficacy and demographic factors such as age have a differential impact on the type of behaviors taken online.
Providing Parents with Online Privacy Information: Approaches in the US and the UK
Authors: STANALAND ANDREA J. S. , LWIN MAY O. , LEONG SUSANNA
Published: September 2009

Policy makers are faced with the task of ensuring that parents are offered information on children's Web sites to help them reduce their children's online privacy risks. This exploratory research compares the approaches of two countries with different regulatory philosophies regarding children's privacy: the United States, with a limited and sectoral approach to general privacy but a formalized approach to children's online privacy, and the United Kingdom, with a comprehensive overarching approach to privacy, but no formal stipulations for children's privacy. We examined privacy statements on 100 children's Web sites from each country in order to compare the products of each regulatory environment.
Privacy in the Information Economy
Authors: LANGENDERFER JEFF , MIYAZAKI ANTHONY D.
Published: September 2009

Although early notions of privacy focused on freedom from intrusion, modern privacy concerns are primarily directed toward control of personal information. Understanding of privacy‐related decisions and consequences, or “privacy literacy,” is an important antecedent to effective information control. A perspective of historical and modern privacy concepts provides directions for future research.
Newly recorded tribe Eurylabini of subfamily Ichneumoninae (Hymenoptera: Ichneumonidae) in Korea
Authors: JEONG Jong‐Chul , CHA Jin‐Yeol
Published: September 2009

The tribe Eurylabini is included in the Korean fauna for the first time. We report an unrecorded genus and species of the tribe Eurylabini in Korean fauna: Eurylabus quadratusUchida. A description and photographs are provided.
Does Property Right Transformation Improve Township and Village Enterprises Performance?
Authors: Du Zhixiong , Izumida Yoichi
Published: September 2009

To date, few observations have been made about the performance improvement that resulted from the property right transformation of the collective‐owned township and village enterprises (TVE) in the middle of 1990s. Using data collected from a questionnaire survey on the privatized TVE and their employees, the present paper provides some empirical evidence about this topic, and the analysis suggests that property right transformation has had a positive impact on sample enterprises' performance, including business improvement, employment expansion, incremental investment and contributions to government revenues. The present study concludes that, from a transient viewpoint, the property right transformation has not distorted local governments' intentions to establish TVE in earlier years.

(Edited by Xinyu Fan)
Prospect for China–Korea Economic Relations
Authors: Lin Justin Yifu
Published: September 2009

This paper briefly reviews the economic performance of China's economic reform starting in 1978, and which it presents personal views on the experiences of Korea's economic development and lessons for China's economic reform. The paper reviews the China‐Korea economic relationship, and explores both the opportunities of China's economic development for Korea and the prospects for Bilateral Economic cooperation. It is estimated that the Chinese economy will maintain dynamic growth for the coming decade. The 2008 Olympic Games and the 2010 World Expo in China will provide further impetuses for Chinese economic development. China's huge market and its rapid economic growth can help the further recovery and development of the Korean economy. At the same time, the further development of the Chinese economy can benefit from financial, technical and managerial support from Korea. The complementarities between the industrial structures of China and Korea will surely push their future economic cooperation into a broader and deeper stage. Bilateral trade will enhance the competitiveness of both nations in the global market and help them achieve mutual prosperity and development.

(Edited by Xinyu Fan)
China's New International Financial Strategy amid the Global Financial Crisis
Authors: Zhang Ming
Published: September 2009

The Chinese Government has stepped up its drive to reconstruct its international financial strategy after the sub‐prime crisis developed into a global financial crisis in 2008. The main aim of the strategy is to reduce the country's dependence on the US dollar in foreign trade, cross‐border capital flows and foreign exchange reserve management. The strategy can be divided into three tiers: renminbi internationalization, regional monetary cooperation and reconstruction of the international monetary regime. So far, the Chinese Government has fared well in the application of all three tiers. We hold that the Chinese Government should continue in the same direction in a coordinated manner despite various challenges it faces.
China's Exchange Rate Movements and Corporate Currency Invoicing Strategies
Authors: Yi Jingtao
Published: September 2009

Since China introduced a new managed floating exchange rate regime in 2005, the persistent appreciation of the renminbi against the US dollar has led Chinese firms to reassess their choice of invoice currency among the dollar and other international alternatives to price their exports. The present paper performs a systematic invoice currency analysis by surveying the published literature, summarizing criteria for decision‐making, and evaluating the choices available to Chinese exporters implementing currency invoicing strategies to maximize expected profits. This study finds that the euro could play an increasing role as the invoice currency of Chinese firms, although the US dollar will still play a dominant role. Chinese exporters might shift gradually from the dollar to the euro in the face of the falling dollar, balancing between the two by necessity.
Bank Reforms, Competition and Efficiency in China's Banking System: Are Small City Bank Entrants More Efficient?
Authors: Lin Hui‐Lin , Tsao Chia‐Chi , Yang Chih‐Hai
Published: September 2009

This paper analyzes technical efficiency in China's banking system by large banks and small city banks as well as the pre‐WTO and post‐WTO accession periods. Using an unbalanced panel dataset for 63 banks over 1997–2006 and employing the stochastic frontier function approach, the empirical results reveal that the new entrants, small city banks, experienced a slightly higher efficiency score than incumbent large banks, on average. Compared with the pre‐WTO accession period, the efficiency score is found to have improved significantly after entry into the WTO as a result of the competition effect. This competition effect is particularly relevant for small city banks. Finally, determinants of X‐inefficiency are examined.
Comparing Operational Efficiency of Mobile Operators in Brazil, Russia, India and China
Authors: Liao Chun‐Hsiung , González Diana B.
Published: September 2009

Using partial factor productivity and data envelopment analysis approaches, this study measures and compares the operational efficiency of the 10 dominant mobile operators in Brazil, Russia, India and China (BRIC) between 2002 and 2006. The results of data envelopment analysis indicate that the two leading Brazilian mobile operators, Vivo and TIM, are fully efficient throughout the entire period of study; however, Indian mobile operators are the least efficient among BRIC operators. Interestingly, the findings of this study verify that full operational efficiency can be achieved by operators with large revenues, such as China Unicom, and by others with medium and small revenues, such as Vivo, TIM and Oi. Partial factor productivity demonstrates that 3 of the 4 Brazilian mobile operators, Vivo, TIM and Oi, have remarkable productivity ratios, and that the state‐owned operator, China Unicom, has the highest revenue per capital expenditure among BRIC operators. In contrast, Indian mobile operators' productivity ratios are generally low compared to other BRIC mobile carriers.
Mirror Neurons, the Motor System and Language: From the Motor Theory to Embodied Cognition and Beyond
Authors: Venezia Jonathan H. , Hickok Gregory
Published: September 2009

The motor theory of speech perception states that phonetic segments in the acoustic speech stream activate stored motor commands in the brain that give rise to perception of discrete speech sounds. The motor theory fell out of favor when growing evidence from lesion and behavioral studies led aspects of the theory to appear untenable. However, with the recent discovery of mirror neurons and their potential role in action understanding, interest in the motor theory of speech perception is renewed. We review the function and properties of mirror neurons in monkeys, and briefly describe the current literature that focuses on the role of a putative human mirror system in cognition and language processing. Further, we describe proposed evidence for the involvement of the motor system in perceptive speech processing, and point out ambiguities in the literature that arise from the tight coupling of sensory and motor processes in speech comprehension. An alternative theory proposing that sensory representations in superior temporal cortex are mapped onto frontal production networks is offered. We cite evidence that confirms the failure of the motor theory to accurately describe perceptive processes in speech, and promote the conclusion that speech representations are fundamentally sensory in nature.
Hyperthermostable acetyl xylan esterase
Authors: Drzewiecki Katharina , Angelov Angel , Ballschmiter Meike , Tiefenbach Klaus‐Jürgen , Sterner Reinhard , Liebl Wolfgang
Published: September 2009

An esterase which is encoded within a Thermotoga maritima chromosomal gene cluster for xylan degradation and utilization was characterized after heterologous expression of the corresponding gene in Escherichia coli and purification of the enzyme. The enzyme, designated AxeA, shares amino acid sequence similarity and its broad substrate specificity with the acetyl xylan esterase from Bacillus pumilus, the cephalosporin C deacetylase from Bacillus subtilis, and other (putative) esterases, allowing its classification as a member of carbohydrate esterase family 7. The recombinant enzyme displayed activity with p‐nitrophenyl‐acetate as well as with various acetylated sugar substrates such as glucose penta‐acetate, acetylated oat spelts xylan and DMSO (dimethyl sulfoxide)‐extracted beechwood xylan, and with cephalosporin C. Thermotoga maritima AxeA represents the most thermostable acetyl xylan esterase known to date. In a 10 min assay at its optimum pH of 6.5 the enzyme's activity peaked at 90°C. The inactivation half‐life of AxeA at a protein concentration of 0.3 µg µl−1 in the absence of substrate was about 13 h at 98°C and about 67 h at 90°C. Differential scanning calorimetry analysis of the thermal stability of AxeA corroborated its extreme heat resistance. A multi‐phasic unfolding behaviour was found, with two apparent exothermic peaks at approximately 100–104°C and 107.5°C. In accordance with the crystal structure, gel filtration analysis at ambient temperature revealed that the enzyme has as a homohexameric oligomerization state, but a dimeric form was also found.
Correlation of matrix metalloproteinase levels with the grade of proliferative vitreoretinopathy in the subretinal fluid and vitreous during rhegmatogenous retinal detachment
Authors: Symeonidis Chrysanthos , Papakonstantinou Eleni , Souliou Efimia , Karakiulakis George , Dimitrakos Stavros A. , Diza Eudoxia
Published: September 2009

Purpose:  We investigated the activity of matrix metalloproteinase (MMP)‐2 and ‐9 and their latent pro‐forms (proMMP‐2, ‐9), and protein levels of MMP‐1, ‐3, ‐8 and tissue inhibitor of MMPs (TIMP)‐1 in the subretinal fluid (SRF) and vitreous of patients with rhegmatogenous retinal detachment (RRD). Potential correlations with proliferative vitreoretinopathy (PVR) grade were determined.

Methods:  Thirty‐seven SRF and 32 vitreous samples from RRD patients and nine vitreous samples from human organ donors (controls), were collected and assayed for MMP‐1, ‐3, ‐8/TIMP‐1 levels using enzyme‐linked immunosorbent assay (ELISA), and for proMMP‐2, ‐9, MMP‐2, ‐9 activity employing gelatine zymography.

Results:  ProMMP‐2, ‐9, MMP‐1, ‐3, ‐9, TIMP‐1 were significantly higher in the SRF and vitreous of RRD patients compared to the vitreous of organ donors. MMP‐8 levels were higher in RRD patients’ SRF. Regarding PVR grade, MMPs and TIMP‐1 were differentially present in SRF and vitreous. PVR grade correlated significantly with the levels of MMP‐2 in SRF, while proMMP‐2, MMP‐1, ‐2, ‐3, ‐8, ‐9 and TIMP‐1 levels correlated with PVR grade in the vitreous.

Conclusion:  MMP/TIMP‐1 levels are elevated in SRF and vitreous during RRD. Significant correlations between PVR grade and MMP‐2 in SRF and proMMP‐2, MMP‐1, ‐2, ‐3, ‐8, ‐9 and TIMP‐1 levels in vitreous were revealed. Investigation of MMP activity in vitreous may provide more valid conclusions compared to SRF pertaining to the role of the MMPs during RRD. The observations of the present study suggest a possible role for MMPs and TIMP‐1 in PVR pathophysiology.
Synthesis of a Rear Wheel Suspension Mechanism With Pure Rectilinear Motion
Authors: Zhao Jing-Shan , Chu Fulei , Feng Zhi-Jing , Zhao Sheng
Published: September 2009

This paper focuses on the synthesis of an independent suspension that can guide the wheel to track a straight line when moving up (jounce) and down (rebound). With displacement subgroups, it first synthesizes a rigid body guidance mechanism and verifies the result through screw theory. To simplify and optimize the loads of each kinematic chain of the knuckle, it investigates the static equations and ultimately synthesizes a symmetric redundant-constraint suspension structure, which could not only eliminate the shambling shocks induced by the jumping of wheels but also decrease the abrasion of tires. Theoretically, only one pair of noncoplanar kinematic chains is necessary to realize straight line guidance. However, a second pair of noncoplanar kinematic chains is particularly utilized to improve the load status of the links. Because of the redundant constraints induced by the suspension structures, the whole weight can be significantly reduced compared with the initial one. ADAMS simulations with a set of real parameters indicate that the rear suspension mechanism proposed in this paper can guide the wheel to follow a rectilinear locus during jounce and rebound. Therefore, this kind of independent suspension can improve the ride and handling properties of advanced vehicles.
An Analytical Approach to Tooth Friction Losses in Spur and Helical Gears—Influence of Profile Modifications
Authors: Velex P. , Ville F.
Published: September 2009

An original displacement-based formulation of tooth friction power losses in spur and helical gears is established, which can account for the influence of tooth profile modifications. Several analytical formulas are derived enabling friction losses to be easily estimated for a wide range of gears at the design stage. Numerous comparisons with both the classic formulas in the literature and the results of numerical simulations are presented, which confirm the accuracy of the proposed approach.
On using moments around the instantaneous center of rotation
Authors: Theron W. F. D.
Published: September 2009

A previously unpublished example is presented to illustrate the advantages of using the instantaneous center as a point around which moments can be calculated.
Introductory helium atomic spectrum analysis
Authors: Abramzon Nina , Siegel P. B.
Published: September 2009

We present a spreadsheet that introduces undergraduate students to the analysis of helium atomic spectrum data.
The Proca equations derived from first principles
Authors: Gondran Michel
Published: September 2009

We show how the Proca equations can be deduced from first principles in a way that is similar to the derivations of the Dirac relativistic electron equation and Maxwell equations.
Inexpensive microscopy for introductory laboratory courses
Authors: Peidle Joseph , Stokes Chris , Hart Robert , Franklin Melissa , Newburgh Ronald , Pahk Joon , Rueckner Wolfgang , Samuel Aravi
Published: September 2009

We present an inexpensive apparatus for bright field and fluorescence microscopy with video capture, suitable for introductory laboratory courses. Experiments on Brownian motion and the Boltzmann distribution of suspended particles in a gravitational field are described. The Boltzmann constant is measured in three ways, and the results fall within 15% of the accepted value.
Plastic CD containers as cylindrical acoustical resonators
Authors: Moloney Michael J.
Published: September 2009

An empty cylindrical CD container is a ready-made acoustical resonant cavity. It requires only two additional holes: one in the base for a small speaker and one for a small microphone in the side. Because the top can rotate with respect to the base, the angular behavior of each resonant mode can be observed in addition to its frequency. The frequency is easily changed, and signals are readily displayed on an oscilloscope. The measured frequencies and angular dependence are in good agreement with theory.
Alternative derivation of the relativistic contribution to perihelic precession
Authors: Lemmon Tyler J. , Mondragon Antonio R.
Published: September 2009

An alternative derivation of the first-order relativistic contribution to perihelic precession is presented. Orbital motion in the Schwarzschild geometry is considered in the Keplerian limit, and the orbit equation is derived for approximate elliptical motion. The method of solution makes use of coordinate transformations and the correspondence principle rather than the standard perturbative approach. The form of the resulting orbit equation is similar to that derived from Newtonian mechanics and includes first-order corrections to Kepler’s orbits due to general relativity. The associated relativistic contribution to perihelic precession agrees with established first-order results. The reduced radius for the circular orbit is in agreement to first-order with that calculated from the Schwarzschild effective potential. The method of solution is understandable by undergraduate students.
Student ideas regarding entropy and the second law of thermodynamics in an introductory physics course
Authors: Christensen Warren M. , Meltzer David E. , Ogilvie C. A.
Published: September 2009

We report on students’ thinking regarding entropy in an introductory calculus-based physics course. We analyzed students’ responses to a variety of questions on entropy changes of an arbitrarily defined system and its surroundings. In four offerings of the same course we found that before instruction, no more than 6% of all students could give completely correct responses to relevant questions posed in both general and concrete contexts. Nearly two-thirds of the students showed clear evidence of conservation-type reasoning regarding entropy. These outcomes were little changed even after instruction. Targeted instruction that guided students to recognize that entropy is not a conserved quantity appears to yield improved performance on qualitative questions related to this concept.
Tabletop demonstration of multiple source interference using ultrasonic transducers
Authors: Tucholski E. J.
Published: September 2009

Superposition of multiple sources, constructive and destructive interference, and array beam forming are common topics demonstrated in undergraduate acoustic classes. The student learning experience is enhanced by building a system with speakers and measuring the resulting amplitude at various angles with a microphone. This experiment is often performed in an anechoic chamber to achieve quantitative agreement between theory and experiment. We have developed a simple tabletop apparatus using inexpensive ultrasonic transducers that yields comparable results without the need to use an anechoic chamber.
Construction and calibration of an impact hammer
Authors: Waltham Chris , Kotlicki Andrzej
Published: September 2009

Impact hammers are used for rapid testing of the frequency-dependent response of structures to excitation. This work demonstrates how an impact hammer can be made from a piezoelectric crystal of the type widely used in barbeque lighters. The hammer was tested by measuring the inertance of a known mobile mass and by measuring the calculable driving-point admittance of rectangular wooden bars. The impact hammer was shown to be robust, easy to build, and to have a low-noise linear output for a wide range of applied forces.
Measurement of electrical conductivity in nonferromagnetic tubes and rods at low frequencies
Authors: Íñiguez J. , Raposo V. , Zazo M.
Published: September 2009

We present a simple and precise method to measure the azimuthal electrical conductivity in nonferromagnetic tubes and rods at low frequencies. The results are readily obtained by analyzing the eddy currents in the sample when it is subjected to an axial harmonic magnetic field. The information about the eddy currents can be obtained from a measurement of the phase of the induced voltage in a short probe coil located inside the tube or around the rod when the sample is axially excited by a long primary coil. At low frequencies, the eddy currents are distributed over the full depth of the sample and any irregularities can be detected when the probe coil is moved along the sample axis.
Secondary school physics availability in an urban setting: Issues related to academic achievement and course offerings
Authors: Kelly Angela M. , Sheppard Keith
Published: September 2009

High school physics is a gateway course for post-secondary study in science, and an essential component in the formation of students’ scientific literacy. The opportunity to study physics is not universally available for children in U.S. schools, particularly in urban areas. Restricted science opportunities result in inequitable participation and a barrier to future participation in STEM-related fields. Although the national trend in physics enrollment has recently shown an increase, the percentage of participation is much lower for students in urban schools. We examined the availability of physics in New York City, and whether access was related to academic achievement measures, such as prior science performance, and graduation and college attendance percentages. High schools that offered physics were compared to those that did not, and patterns in types of available physics courses were examined. The findings substantiate the compelling need to explore the barriers to increased physics access and participation for urban youth.
Control of Spin Precession in a Spin-Injected Field Effect Transistor
Authors: Koo Hyun Cheol , Kwon Jae Hyun , Eom Jonghwa , Chang Joonyeon , Han Suk Hee , Johnson Mark
Published: September 2009

Transistors Switch onto Spin

Using the spin of an electron in addition to, or instead of, the charge properties is believed to have many benefits in terms of speed, power-cost, and integration density over conventional electronic circuits. At the heart of the field of spintronics has been a proposed spin-analog of the electronic transistor, the spin field effect transistor.

Koo
et al.

(p.
1515
) demonstrate the injection and detection of spin between two ferromagnetic contacts and show how the magnitude of the spin-current between the source and drain contacts can be controlled by a voltage applied to a gate. The results present an experimental realization of the concepts described for the spin-transistor.
Macroevolution of Complex Retroviruses
Authors: Katzourakis Aris , Gifford Robert J. , Tristem Michael , Gilbert M. Thomas P. , Pybus Oliver G.
Published: September 2009

A sloth foamy virus sequence indicates that mammals have been infected since the Cretaceous.
An Anomalous Basaltic Meteorite from the Innermost Main Belt
Authors: Bland Philip A. , Spurný Pavel , Towner Martin C. , Bevan Alex W. R. , Singleton Andrew T. , Bottke William F. , Greenwood Richard C. , Chesley Steven R. , Shrbený Lukas , Borovička Jiri , Ceplecha Zdenek , McClafferty Terence P. , Vaughan David , Benedix Gretchen K. , Deacon Geoff , Howard Kieren T. , Franchi Ian A. , Hough Robert M.
Published: September 2009

The Meteorite Who Fell to Earth

Orbital data is available for only a handful of meteorites. Some are found long after they fell to Earth. Others are recovered after they have been observed falling through the atmosphere, but their trajectories are rarely recorded.

Bland
et al.

(p.
1525
) used a photographic camera network located in the Australian desert to track a fireball in the sky, find the meteorite, and establish its orbit. The meteorite is a basaltic achondrite; most such rocks have been traced to the major asteroid Vesta. In this case, the meteorite's isotopic composition and orbital properties suggest a distinct parent asteroid—a different source of basaltic material residing in the innermost main belt.
Biodiversity Conservation and the Millennium Development Goals
Authors: Sachs Jeffrey D. , Baillie Jonathan E. M. , Sutherland William J. , Armsworth Paul R. , Ash Neville , Beddington John , Blackburn Tim M. , Collen Ben , Gardiner Barry , Gaston Kevin J. , Godfray H. Charles J. , Green Rhys E. , Harvey Paul H. , House Brett , Knapp Sandra , Kümpel Noëlle F. , Macdonald David W. , Mace Georgina M. , Mallet James , Matthews Adam , May Robert M. , Petchey Owen , Purvis Andy , Roe Dilys , Safi Kamran , Turner Kerry , Walpole Matt , Watson Robert , Jones Kate E.
Published: September 2009

Any near-term gains in reducing extreme poverty will be maintained only if environmental sustainability is also achieved.
Tracking Progress Toward the 2010 Biodiversity Target and Beyond
Authors: Walpole Matt , Almond Rosamunde E. A. , Besançon Charles , Butchart Stuart H. M. , Campbell-Lendrum Diarmid , Carr Geneviève M. , Collen Ben , Collette Linda , Davidson Nick C. , Dulloo Ehsan , Fazel Asghar M. , Galloway James N. , Gill Michael , Goverse Tessa , Hockings Marc , Leaman Danna J. , Morgan David H. W. , Revenga Carmen , Rickwood Carrie J. , Schutyser Frederik , Simons Sarah , Stattersfield Alison J. , Tyrrell Tristan D. , Vié Jean-Christophe , Zimsky Mark
Published: September 2009

Biodiversity indicators used by policy-makers are underdeveloped and underinvested.
An E3 Ligase Possessing an Iron-Responsive Hemerythrin Domain Is a Regulator of Iron Homeostasis
Authors: Salahudeen Ameen A. , Thompson Joel W. , Ruiz Julio C. , Ma He-Wen , Kinch Lisa N. , Li Qiming , Grishin Nick V. , Bruick Richard K.
Published: September 2009

Iron Sensor

Intracellular iron is an essential cofactor for many proteins, but can also damage macromolecules, so its levels are carefully controlled. Cellular iron homeostasis is mediated by iron regulatory proteins that regulate the expression of genes involved in iron uptake and storage. However, it is not clear how cells sense iron bioavailability (see the Perspective by

Rouault

). Using different approaches,

Salahudeen
et al.

(p.
722
, published online 17 September) and

Vashisht
et al.

(p.
718
, published online 17 September) have identified the F-box protein FBXL5 as a human iron sensor. FBXL5 is part of an E3 ubiquitin ligase complex that regulates the degradation of iron regulatory proteins and thereby cellular iron levels. It contains a hemerythrin domain that binds iron and acts as an iron-dependent regulatory switch, causing the degradation of FBXL5 under low iron conditions. This alternative pathway for the regulation of iron homeostasis has implications for both normal cellular physiology and disease.
Itinerant Ferromagnetism in a Fermi Gas of Ultracold Atoms
Authors: Jo Gyu-Boong , Lee Ye-Ryoung , Choi Jae-Hoon , Christensen Caleb A. , Kim Tony H. , Thywissen Joseph H. , Pritchard David E. , Ketterle Wolfgang
Published: September 2009

Cold Atom Magnetism

Magnetic ordering arises from the strong interactions between atoms, with its origins deeply rooted in quantum mechanics. How the ordering comes about, however, has long been a topic of debate because most condensed-matter systems are limited by a somewhat fixed parameter space. Cold atom systems, by comparison, provide the ability to tune the magnitude and sign of the atom-atom interaction, as well as the density.

Jo
et al.

(p.
1521
; see the Perspective by

Zwerger

) exploit this flexibility to use an ensemble of ultracold fermionic atoms as a “quantum simulator” to explore the possibility of magnetic ordering. As the repulsive interaction between atoms is increased, an instability occurs in the free two-component Fermi gas (or jellium), which results in a phase transition and the ferromagnetic ordering of the atoms.
Three-Color Entanglement
Authors: Coelho A. S. , Barbosa F. A. S. , Cassemiro K. N. , Villar A. S. , Martinelli M. , Nussenzveig P.
Published: September 2009

Entangling Rainbows

Quantum mechanical entanglement is at the heart of quantum information processing. In the future, practical systems will contain a network of quantum components, possibly operating at different frequencies.

Coelho
et al.

(p.
823
, published online 17 September) present a technique that can entangle light beams of three different frequencies. The ability to swap entanglement between different light fields should prove useful in advanced quantum information protocols on systems comprising different operating frequencies.
Seeing the Big Picture on Microbe Distribution
Authors: Patterson David J.
Published: September 2009

The distribution patterns of marine microbes are shaped by dispersal on a global scale.
Itinerant Ferromagnetism with Ultracold Atoms
Authors: Zwerger Wilhelm
Published: September 2009

Cold lithium atoms undergoing strong repulsions can be driven into a state that is an analog of ferromagnetic ordering.
Expanding Functionality Within the Looking-Glass Universe
Authors: Blanke Steven R.
Published: September 2009

Although once thought to be largely irrelevant in the biological world, new and unexpected functions for
d
-amino acids continue to emerge.
Biodiversity Policy Challenges
Authors: Mooney Harold , Mace Georgina
Published: September 2009

Global responses to the deterioration of biodiversity have been slow to emerge, but next month the United Nations (UN) Environment Programme hosts a meeting
*
in Nairobi, Kenya, to discuss the next steps in establishing a new science/policy interface for biodiversity and ecosystem services.The response in this arena still lags far behind negotiations related to climate change, but the meeting is a chance to boost international action, based on strong scientific evidence. An important motivation for creating this interface is meeting the goals of international multilateral agreements, including the Convention on Biological Diversity (CBD), the UN Convention to Combat Desertification, and the Ramsar Convention on Wetlands. Unlike the UN Framework Convention on Climate Change, which has the Intergovernmental Panel on Climate Change, these environmental conventions lack a pre-convention science assessment and have no provision for subsequent government-endorsed, independent science. The meeting in Nairobi will debate, among other issues, how best to make up for this crucial omission.
China First to Vaccinate Against Novel H1N1 Virus
Authors: Stone Richard
Published: September 2009

Earlier this week, China was first off the blocks to launch a mass vaccination campaign against the novel H1N1 virus.
Paper Retracted Following Genome Data Breach
Authors: Holden Constance
Published: September 2009

The
Proceedings of the National Academy of Sciences
has retracted a paper based on embargoed data deposited in dbGaP, the National Institutes of Health's database of genotypes and phenotypes.
Revisions to AP Courses Expected to Have Domino Effect
Authors: Mervis Jeffrey
Published: September 2009

In July, the College Board unveiled the first piece of a major revision of the science syllabi for the Advanced Placement (AP) program, a suite of high school courses intended to mirror introductory college courses that students can receive college credit for passing.
Scrambling to Read the Meaning Of the Sky's Most Ancient Flare
Authors: Bhattacharjee Yudhijit
Published: September 2009

This spring, a seemingly routine gamma ray burst triggered a worldwide race to catch a glimpse of the early universe.
The Z Protein of the New World Arenavirus Tacaribe Virus Has Bona Fide Budding Activity That Does Not Depend on Known Late Domain Motifs
Authors: Urata Shuzo , Yasuda Jiro , de la Torre Juan Carlos
Published: September 2009

The arenavirus small RING finger Z protein has been shown to be the main driving force of budding for several arenaviruses. This Z budding activity was found to be mediated by the late (L)-domain motifs P(T/S)AP and PPXY, located at the C terminus of Z. Here, we show that the Z protein of Tacaribe virus (TACV), a New World arenavirus, buds efficiently from cells despite lacking the canonical L-domain motifs P(T/S)AP and PPXY. Likewise, potential L-domain motifs ASAP and YLCL present in TACV Z did not exhibit any significant contribution to TACV Z budding activity. Budding of TACV Z was Tsg101 independent but required the activity of Vps4A/B. These results indicate that TACV Z utilizes a budding mechanism distinct from that reported for other arenaviruses.
The CDK Inhibitor p21Cip1/WAF1Is Induced by FcγR Activation and Restricts the Replication of Human Immunodeficiency Virus Type 1 and Related Primate Lentiviruses in Human Macrophages
Authors: Bergamaschi Anna , David Annie , Le Rouzic Erwann , Nisole Sébastien , Barré-Sinoussi Françoise , Pancino Gianfranco
Published: September 2009

Macrophages are major targets of human immunodeficiency virus type 1 (HIV-1). We have previously shown that aggregation of activating immunoglobulin G Fc receptors (FcγR) by immune complexes inhibits reverse transcript accumulation and integration of HIV-1 and related lentiviruses in monocyte-derived macrophages. Here, we show that FcγR-mediated restriction of HIV-1 is not due to enhanced degradation of incoming viral proteins or cDNA and is associated to the induction of the cyclin-dependent kinase inhibitor p21Cip1/WAF1(p21). Small interfering RNA-mediated p21 knockdown rescued viral replication in FcγR-activated macrophages and enhanced HIV-1 infection in unstimulated macrophages by increasing reverse transcript and integrated DNA levels. p21 induction by other stimuli, such as phorbol myristate acetate and the histone deacetylase inhibitor MS-275, was also associated with preintegrative blocks of HIV-1 replication in macrophages. Binding of p21 to reverse transcription/preintegration complex-associated HIV-1 proteins was not detected in yeast two-hybrid, pulldown, or coimmunoprecipitation assays, suggesting that p21 may affect viral replication independently of a specific interaction with an HIV-1 component. Consistently, p21 silencing rescued viral replication from the FcγR-mediated restriction also in simian immunodeficiency virus SIVmac- and HIV-2-infected macrophages. Our results point to a role of p21 as an inhibitory factor of lentiviral infection in macrophages and to its implication in FcγR-mediated restriction.
Interaction of the Vaccinia Virus RNA Polymerase-Associated 94-Kilodalton Protein with the Early Transcription Factor
Authors: Yang Zhilong , Moss Bernard
Published: September 2009

A multisubunit RNA polymerase (RPO) encoded by vaccinia virus (VACV), in conjunction with specific factors, transcribes early, intermediate, and late viral genes. However, an additional virus-encoded polypeptide referred to as the RPO-associated protein of 94 kDa (RAP94) is tightly bound to the RPO for the transcription of early genes. Unlike the eight RPO core subunits, RAP94 is synthesized exclusively at late times after infection. Furthermore, RAP94 is necessary for the packaging of RPO and other components needed for early transcription in assembling virus particles. The direct association of RAP94 with NPH I, a DNA-dependent ATPase required for transcription termination, and the multifunctional poly(A) polymerase small subunit/2′-
O
-methyltransferase/elongation factor was previously demonstrated. That RAP94 provides a structural and functional link between the core RPO and the VACV early transcription factor (VETF) has been suspected but not previously demonstrated. Using VACV recombinants that constitutively or inducibly express VETF subunits and RAP94 with affinity tags, we showed that (i) VETF associates only with RPO containing RAP94 in vivo and in vitro, (ii) the association of RAP94 with VETF requires both subunits of the latter, (iii) neither viral DNA nor other virus-encoded late proteins are required for the interaction of RAP94 with VETF and core RPO subunits, (iv) different domains of RAP94 bind VETF and core subunits of RPO, and (v) NPH I and VETF bind independently and possibly simultaneously to the N-terminal region of RAP94. Thus, RAP94 provides the bridge between the RPO and proteins needed for transcription initiation, elongation, and termination.