bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasticity at Ronchamp: the interrelationship of form and light and its plastic manifestation
Authors: Walker David
Published: July 2013

The aim of this study is to chart the manifestation of the Chapel at Ronchamp as a plastic organism and to identify its complex intrinsic visual qualities. To use Gordon Cullen's words, the work involves ‘charting the structure of the subjective world’. Although it has graphic and figurative aspects, the Chapel at Ronchamp achieves existential meaning primarily through plasticity, in other words the visual medium of form, space, polychromy (colour as a relative phenomenon) and texture, revealed in light. As in the case of all spatially rich unicellular works of architecture, the charting of the chapel has involved about ten three-day field studies over a three-year period, recording diurnal and seasonal variations and human activity; because this is uncharted territory it has first been necessary to ‘learn’ the building. The working method has involved recording observations, accompanied by photographic sketches at fifteen minute intervals; the observations have then been correlated with a heliodon model and indicative plans and sections, including sun-paths; the character of the light admitting apertures being of particular significance. Spatial and colour relationships have then been simulated in the studio.
A time for troublemakers
Authors: Aitchison Ross
Published: July 2013

It is not often that a generation of people are offered the opportunity to decide the future course of a nation. In a little over a year around four million people living across Scotland will be afforded the monumental chance to decide whether the place they call home should be an independent country. As both ‘Yes’ and ‘No’ campaigns debate with claim and counterclaim over a wide range of emotive issues neither side can definitively answer, the grassroots campaigns of the pro-independence side are offering imaginative visions of a different Scotland building upon the cultural gains of devolution.
UV and dietary predictors of serum 25-hydroxyvitamin D concentrations among young shift-working nurses and implications for bone density and skin cancer
Authors: Wallingford Sarah C , Jones Glenville , Kobayashi Lindsay C , Grundy Anne , Miao Qun , Tranmer Joan , Aronson Kristan J
Published: July 2013

Objective

In 2011, the US Institute of Medicine updated the definition of vitamin D inadequacy to serum 25-hydroxyvitamin D (25(OH)D) concentration of 30–<50 nmol/l and of deficiency to serum 25(OH)D < 30 nmol/l. We describe the prevalence of these conditions according to these definitions, seasonal variation in 25(OH)D and predictors of serum 25(OH)D concentrations among working, white women.

Design

Participants recorded lifestyle factors and dietary intake and provided fasting blood samples for measurement of serum 25(OH)D in both summer and winter. Predictors of serum 25(OH)D variation were analysed using linear regression and generalized linear mixed models.

Setting

Kingston General Hospital in Kingston, Ontario, Canada, from April 2008 to July 2009.

Subjects

Female premenopausal nurses (n83) working full-time rotating shifts.

Results

Deficient or inadequate vitamin D status was observed in 9 % of participants following summer/autumn and in 13 % following winter/spring. Predictors of serum 25(OH)D concentration were vitamin D supplement use, tanning bed use and season. Tanning bed use increased serum 25(OH)D by 23·24 nmol/l (95 % CI 8·78, 37·69 nmol/l,P= 0·002) on average.

Conclusions

According to the 2011 Institute of Medicine bone health guidelines, over 10 % of nurses had deficient or inadequate vitamin D status following winter. Higher serum concentrations were associated with use of tanning beds and vitamin D supplements. As health promotion campaigns and legal restrictions are successful in reducing tanning bed use among women, our data suggest that increased prevalence of vitamin D inadequacy and deficiency may be a consequence, and that low vitamin D status will need to be countered with supplementation.
Cranberry in radiotherapy: dispelling the myths. A review of the literature
Authors: Gordon Lynne
Published: July 2013

Background

Therapeutic radiographers routinely offer advice to patients regarding treatment-related side effects. Cranberry has long been used as a natural remedy for several health complaints and has more recently been suggested as having a role in the treatment and prophylaxis of urinary tract infection (UTI) and symptoms.

Purpose

The aim of this review was to investigate whether there is a place for cranberry as part of the management of radiation cystitis caused by radiotherapy treatment of pelvic cancers, in order to aid therapeutic radiographers in tailoring their advice regarding pelvic side effects.

Materials and methods

A structured search was carried out using PubMed, CINAHL, Scopus and Cochrane Library databases. A total of 25 articles were selected for review.

Results

Themes of mechanism of action of cranberry, composition of cranberry products, cranberry and UTI, use of cranberry in radiotherapy and further issues to consider were identified and explored.

Conclusion

A lack of high-quality data was identified in the literature reviewed and no firm evidence was found to support the continued recommendation of cranberry as part of management of radiation induced urinary tract side effects. Well-designed randomised controlled trials are required before further recommendations regarding the use of cranberry in radiotherapy are made.
An alternative beads‐on‐a‐string chromatin architecture in Thermococcus kodakarensis
Authors: Maruyama Hugo , Harwood Janet C , Moore Karen M , Paszkiewicz Konrad , Durley Samuel C , Fukushima Hisanori , Atomi Haruyuki , Takeyasu Kunio , Kent Nicholas A
Published: July 2013

We have applied chromatin sequencing technology to the euryarchaeon Thermococcus kodakarensis, which is known to possess histone‐like proteins. We detect positioned chromatin particles of variable sizes associated with lengths of DNA differing as multiples of 30 bp (ranging from 30 bp to >450 bp) consistent with formation from dynamic polymers of the archaeal histone dimer. T. kodakarensis chromatin particles have distinctive underlying DNA sequence suggesting a genomic particle‐positioning code and are excluded from gene‐regulatory DNA suggesting a functional organization. Beads‐on‐a‐string chromatin is therefore conserved between eukaryotes and archaea but can derive from deployment of histone‐fold proteins in a variety of multimeric forms.
Evaluating cell lines as tumour models by comparison of genomic profiles
Authors: Domcke Silvia , Sinha Rileen , Levine Douglas A. , Sander Chris , Schultz Nikolaus
Published: July 2013

Cancer cell lines are frequently used as in vitro tumour models. Recent molecular profiles of hundreds of cell lines from The Cancer Cell Line Encyclopedia and thousands of tumour samples from the Cancer Genome Atlas now allow a systematic genomic comparison of cell lines and tumours. Here we analyse a panel of 47 ovarian cancer cell lines and identify those that have the highest genetic similarity to ovarian tumours. Our comparison of copy-number changes, mutations and mRNA expression profiles reveals pronounced differences in molecular profiles between commonly used ovarian cancer cell lines and high-grade serous ovarian cancer tumour samples. We identify several rarely used cell lines that more closely resemble cognate tumour profiles than commonly used cell lines, and we propose these lines as the most suitable models of ovarian cancer. Our results indicate that the gap between cell lines and tumours can be bridged by genomically informed choices of cell line models for all tumour types.
Characterization of inflamin, the first member of a new family of snake venom proteins that induces inflammation
Authors: Barnwal Bhaskar , Kini R. Manjunatha
Published: July 2013

Unlike other sea snakes, Aipysurus eydouxii feeds exclusively on fish eggs. This unusual feeding habit prompted us to search for unique transcripts in their venom glands. In the present study we expressed a novel cysteine-rich secretory protein containing 94 amino acid residues that was identified in its cDNA library. As it induced inflammation and writhing in animals, this protein was named inflamin. It induced two waves of prostanoid production. The first wave peaked at 10 min and 6-oxo PGF1α (prostaglandin F1α) (6-keto PGF1α) was the major product. The second wave, specifically of 6-oxo PGF1α and PGE2 (prostanglandin E2), started after 2 h. In RAW 264.7 cells, COX-1 (cyclo-oxygenase-1) activity showed a transient increase at 10 min and is responsible for the first wave, but its expression was unaffected. COX-2 was induced after 3 h and is responsible for the second wave. Using specific inhibitors, we showed that cPLA2 (calcium-dependent phospholipase A2), and not sPLA2 (secretory phospholipase A2), iPLA2 (calcium-independent phospholipase A2) or DAG (diacylglycerol) lipase, plays a key role in arachidonate release. The cPLA2 activity showed a transient increase of 62% at 10 min; this increase was due to its phosphorylation and not due to an increase in its expression. Thus inflamin, the first member of a new family of snake venom proteins, leads to an increase in the cPLA2 and COX-1 activity resulting in inflammation and pain.
De‐noising MEMS inertial sensors for low‐cost vehicular attitude estimation based on singular spectrum analysis and independent component analysis
Authors: Wu Z.W. , Yao M.L. , Ma H.G. , Jia W.M.
Published: July 2013

A novel method to de‐noise microelectromechanical system (MEMS) inertial sensors by cascaded integration of singular spectrum analysis (SSA) and independent component analysis (ICA) is proposed to improve the attitude accuracy for low‐cost attitude estimation. The low‐frequency vibration noise and acceleration disturbance induce large errors to attitude estimation since MEMS accelerometers provide attitude measurement for sensor fusion by measuring the gravity vector. It is proposed to remove the low‐frequency vibration noise by SSA and to mitigate the acceleration disturbance by ICA. SSA can effectively separate the trend and periodic vibration noise and ICA can effectively extract the acceleration disturbance with the help of turning rate measured by the yaw gyro. The proposed technique was tested on real road experiments showing significant improvement of attitude accuracy.
Comparison of transmission and reflection all‐pass phasers for analogue signal processing
Authors: Zhang Q. , Caloz C.
Published: July 2013

A comparison of transmission and reflection all‐pass phasers is conducted in terms of resolution for analogue signal processing. First, a formula for resolution is derived based on the fundamental operation of real‐time Fourier transformation. Next, the condition for equal resolution of the two types of phasers is established as a general relation between their coupling coefficients. It is subsequently shown that reflection phasers impose less constraint on the coupling coefficient than transmission phasers.
Source location based on independent doublet array
Authors: Jiang J.C. , Wei P. , Gan L.
Published: July 2013

A single source location method based on a independent doublet array is proposed. It is considered that the source is located at the far‐field of each doublet and the near‐field of the array. The presented method realises direction of arrival estimation by an ESPRIT‐like technique, and the range of the source by array geometry successively. It provides a simple and search‐free estimation method for single near‐field source location. Simulation results are presented that verify the effectiveness of the method.
External torque‐sensing algorithm for flexible‐joint robot based on Kalman filter
Authors: Park Young Jin , Chung Wan Kyun
Published: July 2013

The external torque estimation problem in a 1‐degree‐of‐freedom flexible‐joint robot system with a joint torque sensor is revisited. The flexible‐joint robot has two dynamics, motor‐side and link‐side dynamics, making the problem more complicated. An external torque‐sensing algorithm for the flexible‐joint robot is proposed, which treats these two dynamics simultaneously for extracting external torques applied to the system. The basic structure of the proposed algorithm is illustrated, and the performance is verified by a custom‐designed experimental apparatus for vertical configuration with a gravitational load.
Multilevel motion estimation based on distortion measure in transform domain
Authors: Park Chun‐Su
Published: July 2013

A transform‐domain successive elimination algorithm for block‐based motion estimation (ME) is proposed. First, a method is introduced for calculating the sum of squared differences in the transform domain. Then, based on this method, a new transform‐domain criterion is proposed to eliminate impossible candidates as early as possible. Experimental results show that the proposed algorithm speeds up the ME process by up to a factor of 10 compared with the conventional full search algorithm.
Intrinsic phase noise properties and frequency stability of millimetre‐wave module at 90 GHz
Authors: Bara‐Maillet R. , Parker S.R. , Le Floch J.‐M. , Tobar M.E.
Published: July 2013

A report is presented on the residual intrinsic phase noise properties of a millimetre‐wave module used to generate W‐band signals from an X‐band analogue signal generator. The 90 GHz outputs of two nominally identical millimetre‐wave modules are heterodyned to measure their instantaneous frequency fluctuations and hence infer the close‐to‐carrier phase noise. The fractional frequency stability at 1 s integration time is 2 × 10−14, which corresponds to a total single‐sideband phase noise of −50 dBc/Hz at 1 Hz Fourier frequency offset from the carrier and a residual single‐sideband phase noise of −52 dBc/Hz at 1 Hz offset.
Reconfigurable frequency selective surface for use in secure electromagnetic buildings
Authors: Ford K.L. , Roberts J. , Zhou S. , Fong G. , Rigelsford J.
Published: July 2013

Practical measurements of a reconfigurable frequency selective surface (FSS) designed to stop the transmission of the GSM network protocol are shown. The method uses the time‐varying transmission phase of the FSS to impair a GSM signal transmitted into a building or room, such that the receiver cannot detect the incoming signal. Measurements of the FSS response are shown for varying reconfigurable states and the FSS has been tested against a GSM signal to observe the level of impairment offered by the FSS. It is shown that the FSS can provide up to 35% bit error rate.
Dual‐band metal skin UHF RFID tag antenna
Authors: Du G.H. , Tang T. , Deng Y.
Published: July 2013

A novel dual‐band metal skin UHF radio‐frequency identification tag antenna for 866/915 MHz applications is proposed, which is suitable for attaching to metallic objects. To achieve long read ranges within dual band on an ultra‐thin substrate, the antenna is designed with two patch arrays printed on a flexible substrate polypropylene for low‐cost production. The prototype antenna is fabricated and tested with the commercial tag chip by dual‐port connection. The experiment results show that it has similar radiation patterns for the dual band and the read ranges are 3.5 and 3.6 m for 866 and 915 MHz, respectively, when it is mounted on a metal plate.
Reduction of carbon proximity effects by including AlGaN back barriers in HEMTs on free‐standing GaN
Authors: Kaun S.W. , Wong M.H. , Lu J. , Mishra U.K. , Speck J.S.
Published: July 2013

High‐electron‐mobility transistor (HEMT) structures were regrown by molecular beam epitaxy on GaN‐on‐SiC templates and free‐standing (FS) GaN substrates with very low threading dislocation density (TDD). To ensure a high buffer breakdown voltage, the thickness of the unintentionally doped (UID) GaN buffer layer, dUID, was reduced to 200 nm for the HEMTs regrown on FS GaN. A reduction in TDD entailed an increase in the three‐terminal breakdown voltage for passivated HEMTs. With a low dUID, the proximity effects of the carbon‐doped GaN buffer were evident. A power‐added efficiency (PAE) of 37% and continuous‐wave power output (Pout) of 4.2 W/mm were measured at 4 GHz with a drain bias of 40 V for a HEMT on FS GaN without a back barrier. By including a 5 nm Al0.3Ga0.7N back barrier, PAE and Pout improved to 50% and 6.7 W/mm, respectively, at a drain bias of 40 V.
Analysis of the electric field distribution on insulating supports of dry‐type transformers under high temperature
Authors: González Erick , Gómez Pablo , Espino‐Cortés Fermín P.
Published: July 2013

One of the critical parts for the insulation design of dry‐type transformers is the correct inclusion of the insulating supports between the high‐voltage winding and the metallic clamps at the top and bottom ends. Breakdown along the surfaces of such supports has been observed once the transformers are in operation and therefore over‐dimension is commonly adopted, adding cost and size to the transformer. In this work, a study of the parameters that affect the breakdown voltage in the insulation supports of a standard dip and bake dry‐type transformer is performed. The electric field distribution on different profiles of these supports is modelled using the finite element method. By means of laboratory tests, the effect of the high operation temperatures of the transformer on the voltage breakdown in the supports is also investigated. In addition, modifications to the design of the currently used insulating support are evaluated, aimed at reducing its length without increasing the possibility of breakdown.
Impact of speed ripple on the back‐emf waveform of permanent magnet synchronous machines
Authors: De Kooning Jeroen D. M. , Van de Vyver Jan , Vandoorn Tine L. , Meersman Bart , Vandevelde Lieven
Published: July 2013

Permanent magnet synchronous machines are frequently used in industry because of their high efficiency and favourable dynamic properties. Mechanical limitations and design considerations cause several harmonics in the flux and back‐emf of these machines. The back‐emf harmonics can be measured on the machine terminals if no stator current is present and the neutral point is accessible. The measured harmonics can then be included in a mathematical model of the machine. This measurement is often done for a constant speed. However, when a speed ripple is present, several new harmonics are introduced in the flux and back‐emf. Although the existence of this phenomenon is intuitively clear, it has not yet been investigated in detail and no method exists to calculate these additional harmonics. Nevertheless, the impact of a speed ripple on the back‐emf can become significant in some applications. Therefore in this study, a mathematical model is presented, which allows one to accurately calculate the additional back‐emf harmonics in the presence of speed ripples. Also, it provides more insight in the interaction between speed ripples and harmonics. The mathematical model is extensively validated by means of simulations and experiments.
Modelling and experimental validation of internal short‐circuit fault in salient‐pole synchronous machines using numerical gap function including stator and rotor core saturation
Authors: Hemmati Siroos , Shokri Kojoori Shokrollah , Saied Seyedamin , Lipo Thomas A.
Published: July 2013

In this study, the winding function method is modified and used to calculate the machine inductances in two different cases, namely, a healthy case and a short‐circuited stator winding case. For the first time, a numerical air‐gap function is used in addition to a model of the air gap of salient‐pole machines which considers the stator slot effects. The modified winding function (MWF) method introduced here is more precise when compared with previous methods. This MWF enables one to compute the air‐gap function more accurately. Also a mathematical model that allows taking stator and rotor core saturation into account in both healthy and faulty conditions is presented in this study. Stator and rotor winding currents in healthy and faulty condition, obtained from experimental results, are compared with simulation results to verify the accuracy of the proposed method.
Design and prototyping of an optimised axial‐flux permanent‐magnet synchronous machine
Authors: Mahmoudi Amin , Kahourzade Solmaz , Rahim Nasrudin Abd , Ping Hew Wooi , Uddin Mohammad Nasir
Published: July 2013

This study presents the design and performance analysis of a prototype axial‐flux permanent‐magnet (AFPM) synchronous machine. First, the design of AFPM machine is optimised by genetic algorithm based sizing equation and finite element analysis. The design objectives of this machine are maximum power density, minimum total harmonic distortion (THD) of the sinusoidal back‐electromotive force (back‐EMF) waveform and low cogging torque. Based on the optimised design of the machine a prototype 1 kW, three‐phase, 50 Hz, four‐pole AFPM synchronous machine is built. Then, the performance of the prototype machine is tested to see the cogging torque, torque–speed characteristic, efficiency and the THD of the induced voltage. It is found that the prototype machine validates the design in terms of high‐power density, lowest possible THD of the back‐EMF, low cogging torque while maintaining high efficiency.
Modelling and simulation of a linear switched reluctance force actuator
Authors: Garcia‐Amorós Jordi , Blanqué Molina Balduí , Andrada Pere
Published: July 2013

This study deals with modelling and simulation of a linear switched reluctance force actuator with an original, simple and low‐cost linear encoder. A fast and accurate way of determining linear switched reluctance motors‐characteristics based on two‐dimensional finite element analyses taking into account end‐effects is presented and validated. The linear switched reluctance force actuator is simulated using ‘Matlab‐Simulink’. The proposed actuator has been built and tested. Experimental measurements have confirmed the simulation results according to the proposed method.
Design of buck‐type current source inverter fed brushless DC motor drive and its application to position sensorless control with square‐wave current
Authors: Chen Hung‐Chi , Huang Hung‐He
Published: July 2013

Owing to the widely used brushless DC motors (BDCMs) in high‐efficiency applications, many position sensorless control methods based on voltage source inverters had been developed in the literature. Recently, current source inverters (CSIs) are receiving more and more attention because of their inherent short‐circuit protection characteristics. But no position sensorless control for buck‐type CSI with square‐wave current had been found in the literature. In this study, the buck‐type CSI‐fed BDCM drive is designed and its application to the square‐current position sensorless control is first proposed. The provided simulation and experimental results verify the effectiveness of the proposed CSI‐based position sensorless control.
Fitting coarse-grained distribution functions through an iterative force-matching method
Authors: Lu Lanyuan , Dama James F. , Voth Gregory A.
Published: July 2013

An iterative coarse-graining method is developed for systematically converting an atomistic force field to a model at lower resolution that is able to accurately reproduce the distribution functions defined in the coarse-grained potential. The method starts from the multiscale coarse-graining (MS-CG) approach, and it iteratively refines the distribution functions using repeated applications of the MS-CG algorithm. It is justified on the basis of the force matching normal equation, which can be considered a discrete form of the Yvon-Born-Green equation in liquid state theory. Numerical results for molecular systems involving pairwise nonbonded and three-body bonded interactions are obtained, and comparison with other approaches in literature is provided.
The effect of ultrafast laser wavelength on ablation properties and implications on sample introduction in inductively coupled plasma mass spectrometry
Authors: LaHaye N. L. , Harilal S. S. , Diwakar P. K. , Hassanein A. , Kulkarni P.
Published: July 2013

We investigated the role of femtosecond (fs) laser wavelength on laser ablation (LA) and its relation to laser generated aerosol counts and particle distribution, inductively coupled plasma-mass spectrometry (ICP-MS) signal intensity, detection limits, and elemental fractionation. Four different NIST standard reference materials (610, 613, 615, and 616) were ablated using 400 nm and 800 nm fs laser pulses to study the effect of wavelength on laser ablation rate, accuracy, precision, and fractionation. Our results show that the detection limits are lower for 400 nm laser excitation than 800 nm laser excitation at lower laser energies but approximately equal at higher energies. Ablation threshold was also found to be lower for 400 nm than 800 nm laser excitation. Particle size distributions are very similar for 400 nm and 800 nm wavelengths; however, they differ significantly in counts at similar laser fluence levels. This study concludes that 400 nm LA is more beneficial for sample introduction in ICP-MS, particularly when lower laser energies are to be used for ablation.
Lyapunov-stability of solution branches of rotating disk flow
Authors: van Eeten K. M. P. , van der Schaaf J. , van Heijst G. J. F. , Schouten J. C.
Published: July 2013

This paper investigates the stability of solutions to the problem of viscous flow between an infinite rotating disk and an infinite stationary disk. A random perturbation, satisfying the Von Kármán similarity transformation, is applied to the steady velocity profiles for four solution branches, after which the disturbance propagation is tracked as a function of time. It was found that three of the four solution branches (including the Batchelor solution) were Lyapunov-stable and the development of the Lyapunov-coefficients as a function of the Reynolds number was determined. Stewartson-type of flow was found to be unstable and developed into a flow field corresponding to the Batchelor-solution. The mechanism with which the non-viscous core in this latter type of flow acquired its angular momentum was identified as being dominated by radial convection towards the axis of rotation.
Nurse practitioner succession planning: forward thinking or just an after-thought?
Authors: Raftery Chris
Published: July 2013

This paper examines the concept of backfill and succession planning for an elite speciality nursing group, nurse practitioners. Nurse practitioners work in many public, private, inpatient and outpatient settings across the country. This discussion is relevant to all practicing nurse practitioners, but especially those with their own specific patient group. A nurse practitioner is an elite nursing specialist with specific speciality skills. While present, nurse practitioners can be most effective at holistically managing their patient group. However, if an endorsed nurse practitioner is no longer present, for a short or long interval, their specific skills and abilities cannot be easily substituted or replaced in the short term. This potential compromise in patient care can be detrimental to the developing reputation of the role of the nurse practitioner. In order to address the shortage of specifically skilled nurse practitioners across the country in all specialties, there is a need to forward plan and consider contingencies for succession in the event of short- or long-term absences from the clinical environment. Succession planning is the key to patient safety and the successful implementation of the role of the nurse practitioner. What is known about the topic? While succession planning itself is not a new concept, nurse practitioner role development for the most part has been about advancing innovative nurse-led models of care, as opposed to planning for future needs. What does the paper add? This paper aims to reignite the role development discussion to highlight the need for better alignment of succession planning with the establishment of nurse practitioner roles. What are the implications for the practitioner? Better alignment of succession planning and role development will ensure continuity of nurse practitioner models of care well beyond our pioneering nurse practitioners’ working life.
Seasonal and diurnal variation in the stomatal conductance and paraheliotropism of tedera (Bituminaria bituminosa var. albomarginata) in the field
Authors: Foster Kevin , Ryan Megan H. , Real Daniel , Ramankutty Padmaja , Lambers Hans
Published: July 2013

The mechanisms of drought resistance in perennial legumes are poorly understood. We explored the diurnal and seasonal variation (May, August, February) in stomatal conductance (gs) and paraheliotropism of three tedera accessions (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata) and lucerne (Medicago sativa L.), both perennial legumes, grown in the field. For the tedera accessions, there was a significant reduction in gs during the day in May (late autumn) and February (summer), but there was little reduction for lucerne. The peak leaf angle in the tedera accessions ranged from <40° to 70°, whereas for lucerne, the leaf angle was nearly parallel to incident light at 85°. Leaf water-use efficiency, relative leaf water content and leaf retention were higher for the tedera accessions than for lucerne in February. These results highlight the superior drought resistance of tedera compared with lucerne. The reduction in gs over the day in tedera shows the capacity of this species to reduce water loss quickly when conditions for CO2 fixation relative to water loss are highly unfavourable. The high retention of leaves in summer by tedera is a valuable trait for a perennial pasture plant in Mediterranean environments. Leaf folding, combined with effective stomatal control in summer, provides tedera with a set of physiological responses that confer high drought resistance.
Sexual risk-taking at home and on holidays: the importance of context for the late application of condoms
Authors: Cousins Gráinne , Layte Richard , Ingham Roger , McGee Hannah
Published: July 2013

Background
Several studies have examined condom use during ‘holiday’ sex but have not considered condom errors in this context. This study aims to identify factors associated with late application of condoms during participants’ most recent vaginal intercourse at home and away from home (holidays or short breaks). Method: Participants aged 19–30 years from a national Irish survey were recontacted (n = 388; 51% men; mean age: 23.9 years). Telephone interviews regarding participants’ most recent sex at home (n = 362) and away from home (n = 178) were conducted. Results: A higher proportion reported condom use away from home (79% v. 62%), with a lower prevalence of late application (14% v. 24%). Pregnancy prevention as the primary motive for condom use increased the odds of late application at home (adjusted odds ratio (AOR): 4.56, 95% confidence interval (CI): 2.10–9.90) and away (AOR: 3.97, 95% CI: 1.36–11.59). A weak desire to use a condom also increased the likelihood of late application at home (AOR: 2.40, 95% CI: 1.03–5.62) and away (AOR: 11.18, 95% CI: 2.84–43.98). Subgroup analysis of those reporting both sexual events suggests that young adults take greater sexual risks with casual partners at home compared to away. Conclusions: The findings suggest that young adults take greater sexual risks at home than when away. Regardless of location, young adults are most likely to report late application when they have a weak desire to use a condom and when they use condoms primarily to prevent pregnancy.
tRNA tK
UUU
, tQ
UUG
, and tE
UUC
wobble position modifications fine-tune protein translation by promoting ribosome A-site binding
Authors: Rezgui Vanessa Anissa Nathalie , Tyagi Kshitiz , Ranjan Namit , Konevega Andrey L. , Mittelstaet Joerg , Rodnina Marina V. , Peter Matthias , Pedrioli Patrick G. A.
Published: July 2013

tRNA modifications are crucial to ensure translation efficiency and fidelity. In eukaryotes, the
URM1
and
ELP
pathways increase cellular resistance to various stress conditions, such as nutrient starvation and oxidative agents, by promoting thiolation and methoxycarbonylmethylation, respectively, of the wobble uridine of cytoplasmic

(tK
UUU
),

(tQ
UUG
), and

(tE
UUC
). Although in vitro experiments have implicated these tRNA modifications in modulating wobbling capacity and translation efficiency, their exact in vivo biological roles remain largely unexplored. Using a combination of quantitative proteomics and codon-specific translation reporters, we find that translation of a specific gene subset enriched for AAA, CAA, and GAA codons is impaired in the absence of
URM1
- and
ELP
-dependent tRNA modifications. Moreover, in vitro experiments using native tRNAs demonstrate that both modifications enhance binding of tK
UUU
to the ribosomal A-site. Taken together, our data suggest that tRNA thiolation and methoxycarbonylmethylation regulate translation of genes with specific codon content.
Rapid evolution of the human gut virome
Authors: Minot Samuel , Bryson Alexandra , Chehoud Christel , Wu Gary D. , Lewis James D. , Bushman Frederic D.
Published: July 2013

Humans are colonized by immense populations of viruses, which metagenomic analysis shows are mostly unique to each individual. To investigate the origin and evolution of the human gut virome, we analyzed the viral community of one adult individual over 2.5 y by extremely deep metagenomic sequencing (56 billion bases of purified viral sequence from 24 longitudinal fecal samples). After assembly, 478 well-determined contigs could be identified, which are inferred to correspond mostly to previously unstudied bacteriophage genomes. Fully 80% of these types persisted throughout the duration of the 2.5-y study, indicating long-term global stability. Mechanisms of base substitution, rates of accumulation, and the amount of variation varied among viral types. Temperate phages showed relatively lower mutation rates, consistent with replication by accurate bacterial DNA polymerases in the integrated prophage state. In contrast, Microviridae, which are lytic bacteriophages with single-stranded circular DNA genomes, showed high substitution rates (>10
−5
per nucleotide each day), so that sequence divergence over the 2.5-y period studied approached values sufficient to distinguish new viral species. Longitudinal changes also were associated with diversity-generating retroelements and virus-encoded Clustered Regularly Interspaced Short Palindromic Repeats arrays. We infer that the extreme interpersonal diversity of human gut viruses derives from two sources, persistence of a small portion of the global virome within the gut of each individual and rapid evolution of some long-term virome members.
Temperature-memory polymer actuators
Authors: Behl Marc , Kratz Karl , Noechel Ulrich , Sauter Tilman , Lendlein Andreas
Published: July 2013

Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to erasing this memory effect. Here temperature-memory polymer actuators (TMPAs) based on cross-linked copolymer networks exhibiting a broad melting temperature range (Δ
T
m
) are presented, which are capable of a long-term temperature-memory enabling more than 250 cyclic thermally controlled actuations with almost constant performance. The characteristic actuation temperatures
T
act
s of TMPAs can be adjusted by a purely physical process, guiding a directed crystallization in a temperature range of up to 40 °C by variation of the parameter
T
sep
in a nearly linear correlation. The temperature
T
sep
divides Δ
T
m
into an upper
T
m
range (T >
T
sep
) forming a reshapeable actuation geometry that determines the skeleton and a lower
T
m
range (T <
T
sep
) that enables the temperature-controlled bidirectional actuation by crystallization-induced elongation and melting-induced contraction. The macroscopic bidirectional shape changes in TMPAs could be correlated with changes in the nanostructure of the crystallizable domains as a result of in situ X-ray investigations. Potential applications of TMPAs include heat engines with adjustable rotation rate and active building facades with self-regulating sun protectors.
Universal sheet resistance and revised phase diagram of the cuprate high-temperature superconductors
Authors: Barišić Neven , Chan Mun K. , Li Yuan , Yu Guichuan , Zhao Xudong , Dressel Martin , Smontara Ana , Greven Martin
Published: July 2013

Upon introducing charge carriers into the copper–oxygen sheets of the enigmatic lamellar cuprates, the ground state evolves from an insulator to a superconductor and eventually to a seemingly conventional metal (a Fermi liquid). Much has remained elusive about the nature of this evolution and about the peculiar metallic state at intermediate hole-carrier concentrations (
p
). The planar resistivity of this unconventional metal exhibits a linear temperature dependence (ρ ∝
T
) that is disrupted upon cooling toward the superconducting state by the opening of a partial gap (the pseudogap) on the Fermi surface. Here, we first demonstrate for the quintessential compound HgBa
2
CuO
4+δ
a dramatic switch from linear to purely quadratic (Fermi liquid-like, ρ ∝
T
2
) resistive behavior in the pseudogap regime. Despite the considerable variation in crystal structures and disorder among different compounds, our result together with prior work gives insight into the
p-T
phase diagram and reveals the fundamental resistance per copper–oxygen sheet in both linear (ρ
☐
=
A
1☐
T
) and quadratic (ρ
☐
=
A
2☐
T
2
) regimes, with
A
1☐
∝
A
2☐
∝ 1/p. Theoretical models can now be benchmarked against this remarkably simple universal behavior. Deviations from this underlying behavior can be expected to lead to new insight into the nonuniversal features exhibited by certain compounds.
Modulation of natural killer cell antitumor activity by the aryl hydrocarbon receptor
Authors: Shin June Ho , Zhang Luhua , Murillo-Sauca Oihana , Kim Junmo , Kohrt Holbrook E. K. , Bui Jack D. , Sunwoo John B.
Published: July 2013

The aryl hydrocarbon receptor (AhR) has become increasingly recognized for its role in the differentiation and activity of immune cell subsets; however, its role in regulating the activity of natural killer (NK) cells has not been described. Here, we show that AhR expression is induced in murine NK cells upon cytokine stimulation. We show that in the absence of AhR, NK cells have reduced cytolytic activity and reduced capacity to control RMA-S tumor formation in vivo, despite having normal development and maturation markers. Although AhR was first identified to bind the xenobiotic compound dioxin, AhR is now known to bind a variety of natural exogenous (e.g., dietary) and endogenous ligands. We show that activation of AhR with an endogenous tryptophan derivative, 6-formylindolo[3,2-
b
]carbazole, potentiates NK cell IFN-γ production and cytolytic activity. Further, administration of 6-formylindolo[3,2-
b
]carbazole in vivo enhances NK cell control of tumors in an NK cell- and AhR-dependent manner. Finally, similar effects on NK cell potency occur with AhR dietary ligands, potentially explaining the numerous associations that have been observed in the past between diet and NK cell function. Our studies introduce AhR as another regulator of NK cell activity in vivo.
Vibronic origin of sulfur mass-independent isotope effect in photoexcitation of SO2and the implications to the early earth’s atmosphere
Authors: Whitehill Andrew R. , Xie Changjian , Hu Xixi , Xie Daiqian , Guo Hua , Ono Shuhei
Published: July 2013

Signatures of mass-independent isotope fractionation (MIF) are found in the oxygen (16O,17O,18O) and sulfur (32S,33S,34S,36S) isotope systems and serve as important tracers of past and present atmospheric processes. These unique isotope signatures signify the breakdown of the traditional theory of isotope fractionation, but the physical chemistry of these isotope effects remains poorly understood. We report the production of large sulfur isotope MIF, with Δ33S up to 78‰ and Δ36S up to 110‰, from the broadband excitation of SO2in the 250–350-nm absorption region. Acetylene is used to selectively trap the triplet-state SO2(3B1), which results from intersystem crossing from the excited singlet (1A2/1B1) states. The observed MIF signature differs considerably from that predicted by isotopologue-specific absorption cross-sections of SO2and is insensitive to the wavelength region of excitation (above or below 300 nm), suggesting that the MIF originates not from the initial excitation of SO2to the singlet states but from an isotope selective spin–orbit interaction between the singlet (1A2/1B1) and triplet (3B1) manifolds. Calculations based on high-level potential energy surfaces of the multiple excited states show a considerable lifetime anomaly for33SO2and36SO2for the low vibrational levels of the1A2state. These results demonstrate that the isotope selectivity of accidental near-resonance interactions between states is of critical importance in understanding the origin of MIF in photochemical systems.
Within-mother analysis of seasonal patterns in health at birth
Authors: Currie Janet , Schwandt Hannes
Published: July 2013

A large literature describes relationships between month of birth, birth weight, and gestation. These relationships are hypothesized to reflect the causal impact of seasonal environmental factors. However, recent work casts doubt on this interpretation by showing that mothers with lower socioeconomic status are more likely to give birth in months that are associated with poorer birth outcomes. Seasonality in the numbers of conceptions in different months can also induce a mechanical correlation between preterm birth and month of birth. This paper analyzes the seasonality of health at birth using a large sample of 647,050 groups of US siblings representing 1,435,213 children. By following the same mother over time, we eliminate differences in fixed maternal characteristics as an explanation for seasonal differences in health at birth. We find a sharp trough in gestation length among babies conceived in May, which corresponds to an increase in prematurity of more than 10%. Birth weight conditional on gestation length, however, is found to be strongly hump-shaped over the year, with 8–9 additional g for summer conceptions. We examine several potential mechanisms for explaining seasonality in birth outcomes that have generally been dismissed in the literature on seasonality in rich countries, notably disease prevalence and nutrition. The May trough in gestation length coincides with a higher influenza prevalence in January and February, when these babies are nearing full term, whereas the hump shape in birth weight is associated with a similar pattern in pregnancy weight gain.
Medium-term electricity load forecasting and climate change in arid cities
Authors: Chandrasekharan Bhagyam , Colby Bonnie
Published: July 2013

Electric utilities need to consider how potential changes in climate patterns will affect their peak loads. This study incorporates weather and socio-economic variables into a medium-term load forecasting model to consider potential climate change effects on the challenging summer peak season for utilities in the arid southwestern US. Our ‘average hourly load by month’ model shows marked improvement over a purely autoregressive approach to load forecasting used by some electric utilities. In light of climate change, electric utilities and society can benefit from minimizing inaccuracies in load predictions. Decision-making based on more climate-sensitive forecasts will reduce the water and carbon footprint of electric utilities and improve their investment strategies for renewable energy technologies.
Apoptosis and dysfunction of blood dendritic cells in patients with falciparum and vivax malaria
Authors: Pinzon-Charry Alberto , Woodberry Tonia , Kienzle Vivian , McPhun Virginia , Minigo Gabriela , Lampah Daniel A. , Kenangalem Enny , Engwerda Christian , López J. Alejandro , Anstey Nicholas M. , Good Michael F.
Published: July 2013

Malaria causes significant morbidity worldwide and a vaccine is urgently required. Plasmodium infection causes considerable immune dysregulation, and elicitation of vaccine immunity remains challenging. Given the central role of dendritic cells (DCs) in initiating immunity, understanding their biology during malaria will improve vaccination outcomes. Circulating DCs are particularly important, as they shape immune responses in vivo and reflect the functional status of other subpopulations. We performed cross-sectional and longitudinal assessments of the frequency, phenotype, and function of circulating DC in 67 Papuan adults during acute uncomplicated P. falciparum, P. vivax, and convalescent P. falciparum infections. We demonstrate that malaria patients display a significant reduction in circulating DC numbers and the concurrent accumulation of immature cells. Such alteration is associated with marked levels of spontaneous apoptosis and impairment in the ability of DC to mature, capture, and present antigens to T cells. Interestingly, sustained levels of plasma IL-10 were observed in patients with acute infection and were implicated in the induction of DC apoptosis. DC apoptosis was reversed upon IL-10 blockade, and DC function recovered when IL-10 levels returned to baseline by convalescence. Our data provide key information on the mechanisms behind DC suppression during malaria and will assist in developing strategies to better harness DC’s immunotherapeutic potential.
CD4+ T helper cells use CD154–CD40 interactions to counteract T reg cell–mediated suppression of CD8+ T cell responses to influenza
Authors: Ballesteros-Tato André , León Beatriz , Lund Frances E. , Randall Troy D.
Published: July 2013

CD4+ T cells promote CD8+ T cell priming by licensing dendritic cells (DCs) via CD40–CD154 interactions. However, the initial requirement for CD40 signaling may be replaced by the direct activation of DCs by pathogen-derived signals. Nevertheless, CD40–CD154 interactions are often required for optimal CD8+ T cell responses to pathogens for unknown reasons. Here we show that CD40 signaling is required to prevent the premature contraction of the influenza-specific CD8+ T cell response. CD40 is required on DCs but not on B cells or T cells, whereas CD154 is required on CD4+ T cells but not CD8+ T cells, NKT cells, or DCs. Paradoxically, even though CD154-expressing CD4+ T cells are required for robust CD8+ T cell responses, primary CD8+ T cell responses are apparently normal in the absence of CD4+ T cells. We resolved this paradox by showing that the interaction of CD40-bearing DCs with CD154-expressing CD4+ T cells precludes regulatory T cell (T reg cell)–mediated suppression and prevents premature contraction of the influenza-specific CD8+ T cell response. Thus, CD4+ T helper cells are not required for robust CD8+ T cell responses to influenza when T reg cells are absent.
Metabolic syndrome
Authors: Lawrence Clare , Lawrence Matthew
Published: July 2013

Metabolic syndrome is the term given to a cluster of cardiovascular disease risk factors that includes hyperinsulinaemia, low glucose tolerance, hypertension, central obesity and dyslipidaemia. Syndrome X, also known as Reaven's syndrome, was first defined as a condition in which insulin resistance underpinned the other cardiovascular risk factors of glucose intolerance, hyperinsulinaemia, dyslipidaemia and hypertension. Obesity was not included in this definition; but as this often precedes the initial development of insulin resistance, this has been added to the definition and syndrome X has evolved into the concept of metabolic syndrome. Metabolic syndrome is important because of the increased risk that sufferers have of developing type 2 diabetes, as well as other cardiovascular conditions, including coronary heart disease and stroke, and is a useful predictor of patients predisposed to these disorders. The GP has a key role in the early identification of those patients with metabolic syndrome and the prompt initiation of treatment to prevent these patients developing complications.