bluuebunny/crossref_metadata_2025 huggingface dataset:
Fruit and vegetable intake in Austrian adults: intake frequency, serving sizes, reasons for and barriers to consumption, and potential for increasing consumption
Authors: Schätzer Manuel , Rust Petra , Elmadfa Ibrahim
Published: October 2009

Objective

To assess the intake frequency of fruit and vegetables, serving sizes, reasons for and barriers to consumption, and the potential for increasing fruit and vegetable intake.

Design

A nationwide postal questionnaire survey was conducted in 2006 over all four seasons. The participants were stratified according to occupation and sex. The response rate for 5130 questionnaires sent out was 52·7 %.

Setting

Austria.

Subjects

Austrian adults, aged 19–64 years.

Results

Daily fruit consumption was reported by 57·1 % of the participants and daily vegetable consumption by 36·2 %. On average, 2·1 (sd 1·9) servings (250 (sd 225) g) of fruit and 1·7 (sd 1·3) servings (198 (sd 159) g) of vegetables were consumed daily. Women ate fruit and vegetables both more frequently and in greater quantities than men. Both intake frequency and the number of fruit and vegetable servings were largely independent of seasonal fluctuations. The primary reason for the consumption of both fruit and vegetables was taste. The greatest barrier to higher intake was the perception that current individual consumption was already sufficient. Price did not constitute a relevant barrier in Austria. At present, the potential for increasing fruit and vegetable intake can be estimated at two servings.

Conclusions

Austrian adults still consume less fruit and vegetables than recommended. Strategies to increase intake should pay more attention to the taste instead of the various health aspects.
Dietary carbohydrates and change in physical performance of elderly Europeans: Survey in Europe on Nutrition and the Elderly, a Concerted Action (SENECA) 1993 and 1999
Authors: Kynde Iben , Bjørnsbo Kirsten S , Tetens Inge , Heitmann Berit L
Published: October 2009

Objective

To study dietary glycaemic index (GI) and glycaemic load (GL) in association with physical performance in elderly Europeans.

Design

Cross-sectional and prospective study. Physical performance was measured using the Physical Performance Test (PPT) score on a scale from 0 to 27, where high scores indicate a better physical performance. Habitual diets were measured using diet history interviews and dietary GI and GL were estimated from table values.

Setting

Eight towns/centres from the Survey in Europe on Nutrition and the Elderly, a Concerted Action (SENECA) in 1993 and 1999.

Subjects

Seven hundred and sixty-five men and women, 75–80 years old, were examined in 1993; of these, 357 (47 %) were followed up in 1999, at age 80–85 years.

Results

At baseline, both dietary GI and GL were significantly inversely associated with PPT scores (P= 0·03 andP= 0·05, respectively). When adjusted for age, BMI, physical activity, self-perceived health, chronic diseases and town/centre, the strength of the associations was attenuated and became non-significant (GI,P= 0·08; GL,P= 0·92). Dietary GI/GL were not associated with PPT scores 6 years later.

Conclusions

Among elderly Europeans, a high glycaemic diet was associated with a low physical performance at baseline but not 6 years later. Cross-sectional associations may in part be caused by variations in age, BMI, physical activity, self-perceived health, chronic diseases and geographic location.
Malnutrition in free-living elderly in rural south India: prevalence and risk factors
Authors: Vedantam Aditya , Subramanian Vijay , Vijay Rao Nicholas , John KR
Published: October 2009

Objective

To estimate the prevalence of malnutrition among free-living elderly in a rural population of south India.

Design

Cross-sectional study. Nutritional status was assessed using the Mini Nutritional Assessment (MNA) questionnaire, which is an eighteen-item nutritional screening instrument used in the elderly.

Setting

Kaniyambadi block, a rural development block in the state of Tamil Nadu, south India.

Subjects

Community-dwelling elderly (aged 60 years and above).

Results

As evaluated by the MNA, 14 % of the 227 subjects were malnourished and 49 % were at risk of malnourishment. No significant difference was found between men and women. The majority of the elderly were living with their children, had no income and consumed three meals per day. Older age (P < 0·001), decreased food intake (P < 0·001) and consuming fewer meals (P < 0·001) were independently associated with lower MNA scores.

Conclusions

More than 60 % of the subjects had low MNA scores (<23·5) indicating that deficient protein–energy intake is common among rural elderly of south India and requires more attention.
Adipositaschirurgie – Wissenswertes zu Indikation und Nachsorge
Authors: Scheiwiller  , Sykora
Published: October 2009

Adipositas hat sich in den letzten Jahren in der westlichen Welt zu einem zentralen Problem des Gesundheitswesens entwickelt. Vier von fünf morbid Adipösen entwickeln Komorbiditäten, welche das Mortalitätsrisiko bei Frauen verdoppeln, bei Männern sogar um das Dreifache erhöhen. Die Adipositaschirurgie stellt nach Evidenced-Based-Medicine-Kriterien die beste und effektivste Behandlung dar. Sie resultiert in anhaltendem Gewichtsverlust, Beseitigung oder Verbesserung der Komorbiditäten und damit in einer Verlängerung der Lebenserwartung der Betroffenen. Wie bei allen chirurgischen Verfahren stellt eine korrekte Indikationsstellung die Weichen zum Erfolg. Im Artikel werden die in der Schweiz geltenden Regeln erläutert sowie einige spezielle Indikationssituationen diskutiert. Nach der Adipositaschirurgie kommt der Nachsorge grosse Bedeutung zu. Es werden Komplikationen mechanischer und metabolischer Art nach den verschiedenen Eingriffstypen erklärt und Empfehlungen abgegeben.
The History of Italian Volcanoes Revised by Archeomagnetism
Authors: Tanguy Jean‐Claude , LeGoff Maxime , Arrighi Simone , Principe Claudia , LaDelfa Santo , Patanè Guiseppe
Published: October 2009

The volcanoes Etna and Vesuvius are famous for their historical record, which goes back to Greek and Roman times. The name “Etna” first appears in one of Pindar's Pythian odes (475 B.C.E), and the Vesuvius outburst in 79 C.E. was reported in detail by Pliny the Younger. Other written accounts mention Stromboli and Vulcano (located on the Aeolian Islands), so it might seem that the eruptive history of these Italian volcanoes for the past few millennia is well known.

This is not the case, however, because of many limitations in the historical data. There are enormous gaps due to social events such as wars, barbarian invasions, and the Dark Ages. In particular, the historical record has no valuable account at Etna from 252 to 1062 C.E. Furthermore, the preserved documents are too imprecise to identify the lavas and eruptive systems. Most of the ages prior to 1700 C.E. displayed in the present research catalogs were attributed by pioneering geologists in the 1800s on the mere basis of the morphology of flows. These estimates remained unchanged for nearly a century—for example, the Atlas de L'Etna by Sartorius von Waltershausen [1845] was used unaltered for age attribution of “historical lavas” in much more recent geological maps [e.g., Consiglio Nazionale delle Ricerche (CNR), 1979].
Space Agency Workshop Considers Effect of Climate Change on Infrastructure: Climate Change Impacts and Adaptation: NASA Mission and Infrastructure; Kennedy Space Center, Florida, 28–30 July 2009
Authors: Rosenzweig Cynthia , Brown Molly
Published: October 2009

With centers located throughout the country, NASA could experience a range of climate change hazards. Depending on the region, these hazards are likely to include more extreme and frequent high temperatures, more frequent and intense precipitation events, changing water availability, and sea level rise. These changing climate hazards could undermine key NASA missions by damaging operations and critical infrastructure assets. The specific effects of climate change may include shifting availability, reliability, and cost of water and energy; and changes in safety and operations related to more extreme events (e.g., floods, fire).
How Apollo Flew to the Moon
Authors: Watkins Nick
Published: October 2009

Eos readers who were even young children in the summer of 1969 probably will remember the first Moon landing vividly. If, like myself, they went on to develop a lifelong interest in manned spaceflight, they will have read many accounts in the intervening years, as diverse as Norman Mailer's, Andrew Chaikin's, and the first‐person reminiscences of NASA astronaut Michael Collins. The prospect of another book about the Moon landing at first may seem uninspiring, and I confess this was my original reaction to the prospect of reading this book.

Additionally, in the intervening 40 years since Apollo 11, there have been some superb films including For All Mankind (1989) and In the Shadow of the Moon (2006). The Internet has brought new possibilities for space documentation. The best known Web site on the Apollo missions is the Apollo Lunar Surface Journal, which now is hosted by NASA at http://www.hq.nasa.gov/alsj/. The Web site includes commentary from all of the surviving Moon walkers. Scottish space enthusiast W. David Woods created the companion Apollo Flight Journal, found at http://history.nasa.gov/afj/, which focuses on how the missions actually got to the Moon and back. Now Woods has distilled the information into the book How Apollo Flew to the Moon.
The ARGUS multicollector noble gas mass spectrometer: Performance for40Ar/39Ar geochronology
Authors: Mark D. F. , Barfod D. , Stuart F. M. , Imlach J.
Published: October 2009

We describe a new high‐sensitivity multicollector noble gas mass spectrometer (ARGUS) that has been specifically designed for simultaneous collection of all Ar isotopes and hence is ideally suited for40Ar/39Ar geochronology. The instrument uses a detector housing that holds five Faraday collectors. One collector is equipped with a 1011ohm resistor (for40Ar), and the remaining four are fitted with 1012ohm resistors (for36Ar to39Ar). ARGUS has a mass resolution of 225–250 and a measured sensitivity of 7 × 10−14mol/V at 200μA trap current. During the course of a 1 month run cycle 145 air calibrations yielded a weighted average40Ar/36Ar of 300.67 ± 0.07 (2σ, eight data points rejected, and mean square weighted deviation = 1.18). The ages of three mineral standards (Taylor Creek Rhyolite sanidine, Heidelberg biotite, and Alder Creek sanidine) are within error of the accepted ages, and uncertainties for two are improvements on previously published data. ARGUS decreases analytical time while allowing more measurements to be made at higher precision compared to standard peak‐jumping single‐collector mass spectrometers.
Acceleration by aerosol of a radiative‐thermodynamic cloud feedback influencing Arctic surface warming
Authors: Garrett Timothy J. , Maestas Melissa M. , Krueger Steven K. , Schmidt Clinton T.
Published: October 2009

Recent work suggests that short‐lived pollutants with mid‐latitude origins are contributing to observed warming of the Arctic surface. Candidate mechanisms include an “aerosol indirect effect” associated with increases in cloud longwave emissivity: small cloud droplets associated with polluted conditions are efficient absorbers and emitters of longwave radiation. Here, we argue that the associated surface warming can be temporarily amplified: particulate pollution, by increasing cloud emissivity, additionally accelerates a pre‐existing positive feedback loop between cloud top radiative cooling and new droplet condensation.
Estimation of sea ice thickness distributions through the combination of snow depth and satellite laser altimetry data
Authors: Kurtz Nathan T. , Markus Thorsten , Cavalieri Donald J. , Sparling Lynn C. , Krabill William B. , Gasiewski Albin J. , Sonntag John G.
Published: October 2009

Combinations of sea ice freeboard and snow depth measurements from satellite data have the potential to provide a means to derive global sea ice thickness values. However, large differences in spatial coverage and resolution between the measurements lead to uncertainties when combining the data. High‐resolution airborne laser altimeter retrievals of snow‐ice freeboard and passive microwave retrievals of snow depth taken in March 2006 provide insight into the spatial variability of these quantities as well as optimal methods for combining high‐resolution satellite altimeter measurements with low‐resolution snow depth data. The aircraft measurements show a relationship between freeboard and snow depth for thin ice allowing the development of a method for estimating sea ice thickness from satellite laser altimetry data at their full spatial resolution. This method is used to estimate snow and ice thicknesses for the Arctic basin through the combination of freeboard data from ICESat, snow depth data over first‐year ice from AMSR‐E, and snow depth over multiyear ice from climatological data. Due to the nonlinear dependence of heat flux on ice thickness, the impact on heat flux calculations when maintaining the full resolution of the ICESat data for ice thickness estimates is explored for typical winter conditions. Calculations of the basin‐wide mean heat flux and ice growth rate using snow and ice thickness values at the ∼70 m spatial resolution of ICESat are found to be approximately one‐third higher than those calculated from 25‐km mean ice thickness values.
Calculating distributed glacier mass balance for the Swiss Alps from regional climate model output: A methodical description and interpretation of the results
Authors: Machguth H. , Paul F. , Kotlarski S. , Hoelzle M.
Published: October 2009

This study aims at giving a methodical description of the use of gridded output from a regional climate model (RCM) for the calculation of glacier mass balance distribution for the perimeter of the Swiss Alps. The mass balance model runs at daily steps and 100 m spatial resolution, while the regional model (REMO) RCM provides daily grids (∼18 km resolution) of dynamically downscaled reanalysis data. A combination of interpolation techniques and simple subgrid parameterizations is applied to bridge the gap in spatial resolution and to obtain daily input fields of air temperature, global radiation, and precipitation. Interpolation schemes are a key element and thus we test different interpolators. For validation, computed mass balances are compared to stake measurements and time series (1979–2003) of observed mass balance. The meteorological input fields are compared to measurements at weather stations. The applied inverse distance weighting introduces systematic biases due to spatial autocorrelation, whereas thin plate splines preserve the characteristics of the RCM output. While summer melt at point locations on several glaciers is well reproduced by the model, accumulation is mostly underestimated. These systematic shifts are correlated to biases of the meteorological input fields. Time series of mass balance obtained from the model run agree well with observed time series. We conclude that the gap in spatial resolution is not a major drawback, given that interpolators and parameterizations are selected upon detailed considerations. Biases in RCM precipitation are a major source for the observed underestimations in mass balance and have to be corrected prior to operational use of the presented approach.
Characterizing chlorine oxidation of dissolved organic matter and disinfection by‐product formation with fluorescence spectroscopy and parallel factor analysis
Authors: Beggs Katherine M. H. , Summers R. Scott , McKnight Diane M.
Published: October 2009

Relationships between chlorine demand and disinfection by‐product (DBP) formation during chlorination and fluorescence of dissolved organic matter (DOM) were developed. Fluorescence excitation and emission (EEM) spectroscopy was employed, and parameters including fluorescence index, redox index, and overall fluorescence intensity (OFI) were correlated to chlorine demand and DBP formation. The EEMs were also analyzed using a well established global parallel factor analysis (PARAFAC) model which resolves the fluorescence signal into 13 components, including quinone‐like and protein‐like components. Over an 8‐day chlorination period the OFI and sum of the 13 PARAFAC loadings decreased by more than 70%. The remaining identified quinone‐like compounds within the DOM were shifted to a more oxidized state. Quinone fluorescence was strongly correlated to both reduced fluorescence intensity and to chlorine demand which indicates that fluorescence may be used to track the chlorine oxidation of DOM. Quinone fluorescence was also correlated strongly with both classes of regulated DBPs: total trihalomethanes and haloacetic acids. Quinone‐like components were found to be strongly correlated to overall, short‐term, and long‐term specific DBP formation. The results of this study show that fluorescence is a useful tool in tracking both DOM oxidation and DBP formation during chlorination.
Limitations of the modeling of geomagnetically induced currents in the South African power network
Authors: Ngwira Chigomezyo M. , McKinnell Lee‐Anne , Cilliers Pierre J. , Viljanen Ari , Pirjola Risto
Published: October 2009

Geomagnetically induced currents (GICs) are known to affect electric power systems in both the midlatitude and high‐latitude regions. Monitoring of GICs in the southern African electrical power grid first started in 1998 with the installation of the Electric Power Research Institute Sunburst monitoring system. Recent research efforts in South Africa have shown that the modeling of GICs is effectively improved by the use of a multilayered ground conductivity model and a modified set of network coefficients. This paper reports on an investigation into the reliability of a new GIC model versus the distance between the magnetometer stations and the GIC measuring site using recent developments within this field and the South African context. Results show that the modeling of GICs degrades with increasing distance between the geomagnetic observation station and the GIC site and that the newly developed GIC model is only appropriate for the specific geomagnetic station and GIC site pair.
Upscaling transport with mass transfer models: Mean behavior and propagation of uncertainty
Authors: Fernàndez‐Garcia D. , Llerar‐Meza G. , Gómez‐Hernández J. Jaime
Published: October 2009

The choice of an adequate large‐scale conceptual transport model constitutes a major challenge associated with the upscaling of solute transport. Among the different alternatives to the classical advection‐dispersion model, the (multirate) mass transfer model has been proposed as a valuable and convenient alternative to model the large‐scale behavior of solute transport. This paper evaluates the use of mass transfer models as a constitutive equation for upscaling solute transport. To achieve this, we compare Monte Carlo simulations of solute transport at two different support scales. Transport simulations performed at the smallest scale represent a set of reference transport solutions described at a high resolution, which are contrasted against transport simulations obtained using an upscaled model (low resolution). Several formulations of the multirate mass transfer model, which differ in the type of memory function (single rate, double rate, and truncated power law), are used as a constitutive transport equation. The large‐scale scenario represents a simplified model obtained by partially homogenizing the reference solution. Results show that the double‐rate and the truncated power law mass transfer models are capable of properly describing the ensemble average behavior of the main features associated with the integrated breakthrough curves. However, the uncertainty associated with the upscaled mass transfer models was substantially smaller than that attributed to the reference solution. Importantly, the cumulative distribution function of concentrations associated with the upscaled model follows a distribution similar to the reference solution but with smaller statistical dispersion. The reason is that while appropriate memory functions can be used to preserve the residence time distribution of mass particles during upscaling, the lack of memory in space prevents the model from reproducing mass fluxes in all directions. Specifically, the reproduction of mass fluxes taking place at the interface between two homogenized blocks of the upscaled model is not satisfied, thus providing a poor description of the spatial distribution of mass particles in a given realization.
Glycogen Metabolism as a Marker of Astrocyte Differentiation
Authors: Brunet JF , Allaman I , Magistretti PJ , Pellerin L
Published: October 2009

Glycogen is a hallmark of mature astrocytes, but its emergence during astrocytic differentiation is unclear. Differentiation of E14 mouse neurospheres into astrocytes was induced with fetal bovine serum (FBS), Leukemia Inhibitory Factor (LIF), or Ciliary Neurotrophic Factor (CNTF). Cytochemical and enzymatic analyses showed that glycogen is present in FBS- or LIF- but not in CNTF-differentiated astrocytes. Glycogenolysis was induced in FBS- and LIF-differentiated astrocytes but glycogen resynthesis was observed only with FBS. Protein targeting to glycogen mRNA expression appeared with glial fibrillary acidic protein and S100β in FBS and LIF conditions but not with CNTF. These results show that glycogen metabolism constitutes a useful marker of astrocyte differentiation.
The Impact of Erythropoietin on Short-Term Changes in Phosphorylation of Brain Protein Kinases in a Rat Model of Traumatic Brain Injury
Authors: Valable Samuel , Francony Gilles , Bouzat Pierre , Fevre Marie-Cécile , Mahious Nouara , Bouet Valentine , Farion Régine , Barbier Emmanuel , Lahrech Hana , Remy Chantal , Petit Edwige , Segebarth Christoph , Bernaudin Myriam , Payen Jean-François
Published: October 2009

We found that recombinant human erythropoietin (rhEPO) reduced significantly the development of brain edema in a rat model of diffuse traumatic brain injury (TBI) (impact-acceleration model). In this study, we investigated the molecular and intracellular changes potentially involved in these immediate effects. Brain tissue nitric oxide (NO) synthesis, phosphorylation level of two protein kinases (extracellular-regulated kinase (ERK)-1/-2 and Akt), and brain water content were measured 1 (H1) and 2 h (H2) after insult. Posttraumatic administration of rhEPO (5,000 IU/kg body weight, intravenously, 30 mins after injury) reduced TBI-induced upregulation of ERK phosphorylation, although it increased Akt phosphorylation at H1. These early molecular changes were associated with a reduction in brain NO synthesis at H1 and with an attenuation of brain edema at H2. Intraventricular administration of the ERK-1/-2 inhibitor, U0126, or the Akt inhibitor, LY294002, before injury showed that ERK was required for brain edema formation, and that rhEPO-induced reduction of edema could involve the ERK pathway. These results were obtained in the absence of any evidence of blood–brain barrier damage on contrast-enhanced magnetic resonance images. The findings of our study indicate that the anti edematous effect of rhEPO could be mediated through an early inhibition of ERK phosphorylation after diffuse TBI.
Regulatory factors controlling transcription of Saccharomyces cerevisiae IXR1 by oxygen levels: a model of transcriptional adaptation from aerobiosis to hypoxia implicating ROX1 and IXR1 cross-regulation
Authors: Castro-Prego Raquel  , Lamas-Maceiras Mónica , Soengas Pilar , Carneiro Isabel , González-Siso Isabel , Cerdán M. Esperanza
Published: October 2009

Ixr1p from Saccharomyces cerevisiae has been previously studied because it binds to DNA containing intrastrand cross-links formed by the anticancer drug cisplatin. Ixr1p is also a transcriptional regulator of anaerobic/hypoxic genes, such as SRP1/TIR1, which encodes a stress-response cell wall manoprotein, and COX5B, which encodes the Vb subunit of the mitochondrial complex cytochrome c oxidase. However, factors controlling IXR1 expression remained unexplored. In the present study we show that IXR1 mRNA levels are controlled by oxygen availability and increase during hypoxia. In aerobiosis, low levels of IXR1 expression are maintained by Rox1p repression through the general co-repressor complex Tup1–Ssn6. Ixr1p itself is necessary for full IXR1 expression under hypoxic conditions. Deletion analyses have identified the region in the IXR1 promoter responsible for this positive auto-control (nucleotides −557 to −376). EMSA (electrophoretic mobility-shift assay) and ChIP (chromatin immunoprecipitation) assays show that Ixr1p binds to the IXR1 promoter both in vitro and in vivo. Ixr1p is also required for hypoxic repression of ROX1 and binds to its promoter. UPC2 deletion has opposite effects on IXR1 and ROX1 transcription during hypoxia. Ixr1p is also necessary for resistance to oxidative stress generated by H2O2. IXR1 expression is moderately activated by H2O2 and this induction is Yap1p-dependent. A model of IXR1 regulation as a relay for sensing different signals related to change in oxygen availability is proposed. In this model, transcriptional adaptation from aerobiosis to hypoxia depends on ROX1 and IXR1 cross-regulation.
Aaron Klug wins Nobel prize in chemistry
Authors: Schwarzschild Bertram M.
Published: October 2009

The Royal Swedish Academy of Sciences has awarded the 1982 Nobel Prize in Chemistry to Aaron Klug, “for his development of crystallographic electron microscopy and his structural elucidation of biologically important nucleic acid–protein complexes.” Klug's academic degrees are in physics. After taking a master's degree at the University of Capetown in x-ray crystallography, he received his PhD in solid-state physics at Cambridge in 1952. Since 1962 he has been at the (British) Medical Research Council's Laboratory of Molecular Biology in Cambridge.
Alfred Lee Loomis—last great amateur of science
Authors: Alvarez Luis W.
Published: October 2009

The beginning of this century marked a profound change in the manner in which science was pursued. Before that time, most scientists were independently wealthy gentlemen who could afford to devote their lives to the search for scientific truth—Lord Cavendish, Charles Darwin, Count Rumford, and Lord Rayleigh come to mind. But after the turn of the century, university scientists found it possible to earn a living teaching students, while doing research “on the side.” So the true amateur has almost disappeared—Alfred Loomis may well be remembered as the last of the great amateurs of science. He had distinguished careers as a lawyer, as an Army officer and as an investment banker before he turned his full energies to the pursuit of scientific knowledge, first in the field of physics and later as a biologist. By any measure that can be employed, he was one of the most influential physical scientists of this century:
The Nuclear Freeze: The freeze—deep or shallow?
Authors: Lewis Harold W.
Published: October 2009

The trouble with trite and banal sayings is that they are sometimes painfully to the point. In the case of the freeze, the observation that comes to mind is that to every complex problem there exists a solution that is simple, appealing, and wrong. Wrong may be too strong a term for the freeze proposal—it is wrong only in the sense that it is wrong to give laetrile to a cancer patient. In both cases there is little intrinsic harm done, unless the patient really believes the treatment will contribute to the cure of his disease, and thereby substitutes wishful thinking for therapy.
Frequency measurements of optical radiation
Authors: Baird Kenneth M.
Published: October 2009

Among the remarkable facts of modern technology, one of the most striking is that the possibility is at hand of making an exact count of cyclical events that occur at a rate of over 500 million in a microsecond; this will be the likely result of present work on the measurement of the frequency of optical radiation and the use of optical resonances at frequency standards. The actual counting of the exact frequency of optical radiation or locking its oscillations to microwave standards is still very much in the development stage; however, its feasibility has already been demonstrated in experiments such as a recent measurement of the frequency of a visible laser emission, a feat that gained a recognition not often accorded scientists: mention in the Guinness Book of Records for the highest frequency measured! A number of laboratories are actively engaged in setting up systems for precisely relating optical and microwave standards. The Institute for Semiconductor Physics in Novosibirsk, for example, has announced the first “optical clock,” in which microwaves were locked to the 3.39-micron absorption line in methane.
Lynch report on synchrotron radiation
Authors: Lubkin Gloria B.
Published: October 2009

Last summer the Solid State Sciences Committee of the National Academy of Sciences convened a subcommittee on synchrotron radiation facilities. The subcommittee was established to help assess the present status of the facilities and make projections for their future utilization.
The structure of the nucleon
Authors: Brown Gerald E. , Rho Mannque
Published: October 2009

We have known for years that the nucleon must have a finite size. In the 1950s, with the development of quantitative calculational techniques in quantum electrodynamics, there were many attempts to describe the size of the nucleon, but none was successful. The advent of quark physics and the demonstration through high-energy deep inelastic scattering of electrons by nucleons that there are three objects in the central nucleon core, and that these objects behave at high energies as if they are free and massless, gave impetus to a new description of nucleonic structure. Ever since Hendrik A. Lorentz's work on the theory of the electron, we have been trying to give elementary particles finite sizes to make their self energy finite. Whereas Lorentz introduced rods to hold his extended electron together (the method did not work), we now believe that the vacuum exerts a pressure on the “bubbles,” or “bags,” that we have to make to allow quarks to exist, and that this pressure keeps the bubbles from expanding. As the drawings in figure 1 and on the cover of this issue indicate, we can think of the nucleon as three colored quarks in such a bubble, surrounded by a cloud of mesons.
What price security?
Authors: Corson Dale
Published: October 2009

“There is an overlap between technological information and national security which inevitably produces tension. This tension results from the scientist's desire for unconstrained research and publication on the one hand, and the Federal government's need to protect certain information from potential foreign adversaries who might use that information against this nation. Both are powerful forces. Thus, it should not be a surprise that finding a workable and just balance between them is quite difficult.” So said Admiral Bobby R. Inman, then Deputy Director of the Central Intelligence Agency, in a speech at the 7 January 1982 meeting of the American Association for the Advancement of Science.
Random magnetic fields reduce critical dimensionality
Authors: von Foerster Thomas
Published: October 2009

Recent work, both experimental and theoretical, on the magnetic-ordering transition in dilute antiferromagnets has posed a new set of questions about the competition between order and disorder in physical systems. While neither theory nor experiment has yet given any conclusive answers, the discussion itself is providing some interesting examples of cross-fertilization between different areas of physics.
Fractional quantum Hall effect indicates novel quantum liquid
Authors: Schwarzschild Bertram M.
Published: October 2009

A quite unanticipated extension of the quantized Hall effect appears to have provided us a glimpse of an exotic new state of matter—a two-dimensional quantum liquid of electrons, rendered essentially incompressible by the density quantization of its ground states, whose excitations are quasiparticles of fractional electric charge.
25 years of AAPM
Authors: Suntharalingam Nagalingam
Published: October 2009

The American Association of Physicists in Medicine was established in 1958 to promote scientific communication among practicing physicists in medicine. Today the AAPM has a membership of over 2000 and is the largest organized body of medical physicists in any country. Members of the AAPM, through their research and development activities and as important participants of a medical professional team, play a significant role in promoting the delivery of high-quality health care to the public. Medical physicists have made important contributions to medical practice, especially in the diagnosis and treatment of cancer. Early in this century, physicists played a vital role in developing the use of radiation for the eradication of cancerous tissues. Today medical physicists are working on diagnostic imaging and the application of computers to medicine. John Laughlin discusses some of the history of these developments in his article on page 26, and Paul Moran, Jerome Nickles and James Zagzebski describe the current state of medical imaging on page 36. Medical physicists are also involved in areas such as audiology, opthalmology, endocrinology, physiology, cardiology, physical therapy and general medical instrumentation. Because of the impact of advances in high technology, medical physics has grown rapidly, and today it is recognized as an essential discipline in discipline in medicine.
Atmospheric calculations suggest a nuclear winter
Authors: Levi Barbara G.
Published: October 2009

Might the fiery explosions from a massive nuclear war cast a cold and dark shadow over vast regions of the Earth? That gloomy possibility has been predicted by atmospheric chemists and physicists who have recently tried to quantify the environmental effects of the soot, dust and other emissions from a hypothetical nuclear exchange. The litany of known major effects from nuclear weapons—blast, fire, fallout and possibly stratospheric ozone depletion—always seemed horrible enough. Last year, Paul J. Crutzen (Max Planck Institute for Chemistry) and John W. Birks (University of Colorado) suggested that another effect might be severe enough to go on that list: the black curtain of smoke from fires initiated in a large-scale nuclear attack. (See PHYSICS TODAY, October 1982, page 17.) The new work now indicates that the phenomenon might be severe enough to lower temperatures over large regions of Earth below the freezing mark, even in summer, for perhaps months after a massive nuclear exchange. Richard Turco (R&D Associates), who participated in the study, has coined the phrase “nuclear winter” to describe the phenomenon.
Industry—university research programs
Authors: Smith Kenneth A.
Published: October 2009

Cooperative research ventures between industrial sponsors and universities are attracting increasing attention, not only because they offer benefits for both parties, but also because they promise to improve technology transfer for the nation as a whole. Yet there are risks inherent in such arrangements, as much recent press coverage suggests. This press attention reflects a concern that the needs of industrial sponsors for proprietary secrecy and other competitive advantages may undermine academic traditions of open scientific exchange. I shall examine these issues in the light of our experience with joint programs at MIT. I am not presenting MIT as a paradigm for success in this area, but we have had, perhaps, more experience with these arrangements than any other campus (see table, page 27); also, these are the arrangements with which I am most familiar. Our experiences at MIT have led me to conclude that the incentives for both parties must, from the outset, be clarified and assessed, for they are key to the evolution of a strong and healthy partnership. I shall also discuss means we have found useful for resolving areas of innate conflict between the industrial and academic perspectives, and I shall identify the kinds of conditions we have found essential for the long-term success of these arrangements.
Fermilab's superconducting synchrotron strives for 1 TeV
Authors: Lubkin Gloria B.
Published: October 2009

The first high-energy superconducting synchrotron in the world, the Tevatron, at Fermilab, accelerated protons to 512 GeV last July. By the time of the 12th International Conference on High-Energy Accelerators held at Fermilab in August, the Tevatron had reached 700 GeV. Since October it has been used for fixed-target experiments at 400 GeV. This month Fermilab plans to raise the energy to 750 GeV or so and then run experiments at that energy until July. During the summer, the lab plans to repair marginal magnets and director Leon Lederman hopes the Tevatron will by November indeed be worthy of its name, accelerating protons close to 1000 GeV or 1 TeV. Meanwhile, an antiproton source is being constructed; in 1986 the lab expects to have a pp̄ collider ready for experiments with as much as 1 TeV in each beam.
A theorist's philosophy of science
Authors: Robinson Helier J.
Published: October 2009

There is a temperamental difference among thinkers that has produced a spectrum of attitudes among them, in all realms of thought, throughout the history of ideas. This difference is the preference, in the one case, for the concrete over the abstract, and in the other for the abstract over the concrete. In science, this temperamental difference distinguishes experimentalists and theorists; in mathematics it distinguishes applied and pure mathematicians; and in philosophy it distinguishes empiricists and rationalists. Thus experimentalists are concerned with concrete apparatus in the laboratory, or concrete specimens in the field, while the nearest that theorists get to experimenting is the “thought experiment,” which cannot be performed in any laboratory. Similarly, although all mathematics is abstract, applied mathematics is less so than pure mathematics; applied mathematicians are concerned with mathematics that relates to the concrete world around them, while extreme pure mathematicians consider such concrete application unimportant at best and an adulteration of mathematics at worst.
Accomplishments and promise of transplutonium research
Authors: Keller O. Lewin , Hoffman Darlene C. , Penneman Robert A. , Choppin Gregory R.
Published: October 2009

Fifty years ago the periodic table of chemical elements appeared to be complete. Most of the gaps left in the table by Dmitri Mendeleev in 1869 had been filled in, and it appeared that with elements 43, 61, 85, and 87, the periodic table of 92 elements—hydrogen to uranium—would be fully realized.
Orbiting gyro test of general relativity
Authors: Levi Barbara G.
Published: October 2009

Over twenty years have elapsed since Leonard Schiff at Stanford and, independently, George E. Pugh at the Defense Department predicted that a gyroscope in orbit about Earth would precess as a consequence of Einstein's general theory of relativity. Such behavior depends on an aspect of the theory of gravity that remains untested to this day. Although the concept is simple, the experiment is formidable: The precession is about 44 milliarcsec/year, to be measured with an accuracy of 1 milliarc-sec per year. Undaunted, Schiff, together with Stanford colleagues William Fairbank and Robert Cannon, respectively, set up a program to develop the experiment. Since 1962, a Stanford team led by Francis Everitt and later having the support of NASA's Marshall Space Flight Center, has patiently and persistently toppled many technical barriers, bringing the experiment from the realm of the improbable into the world of the possible. In late 1980, a committee of 16 scientists and engineers convened by NASA spent five days reviewing the technical readiness of the experiment, which is called the Gravity Probe B. They gave it a sound endorsement and concluded it was now ready to proceed to its flight phase.
A debate: Retire FORTRAN?: Yes
Authors: McGraw James R.
Published: October 2009

What role can programming languages play in our continuing efforts for high-speed computation, and what role should they play? The overwhelming majority of high-speed computing is now done in FORTRAN on large vector machines such as the Cray 1 and the CDC Cyber 205. While the exact nature of future supercomputers is unclear, by almost all indications they will be multiprocessors. Conservative plans would link on the order of 64 processors, while more aggressive approaches, such as the “data flow” strategy, would link several thousand processors. In either case, the goal is to arrange each program to use as many processors as needed to complete execution in the shortest amount of time. To what extent can languages and their associated compilers assist us in reaching this goal?
A debate: Retire FORTRAN?: No
Authors: Kuck David J. , Wolfe Michael
Published: October 2009

To take full advantage of the ever more complex architectures of the latest supercomputers, users are having to write increasingly intricate programs. Thus, one of the most pressing questions associated with the powerful new concurrent processors is how to make them practical for ordinary users. In our opinion, answering this question means figuring out how to use algorithms, languages and compilers to give users four crucial capabilities and tools, namely

▸ The ability to use old programs, in old languages, as well as new programs, in old or new languages.

▸ New languages that allow one to express, in a well-structured form, algorithms that are amenable to parallel processing.

▸ Software that is able to exploit effectively all available architectural features, for use in developing and compiling programs in old and new languages.

▸ Packages and library routines that provide standard algorithms that are very amenable to parallel processing.
Functional interchangeability of rod and cone transducin α-subunits
Authors: Deng Wen-Tao , Sakurai Keisuke , Liu Jianwen , Dinculescu Astra , Li Jie , Pang Jijing , Min Seok-Hong , Chiodo Vince A. , Boye Sanford L. , Chang Bo , Kefalov Vladimir J. , Hauswirth William W.
Published: October 2009

Rod and cone photoreceptors use similar but distinct sets of phototransduction proteins to achieve different functional properties, suitable for their role as dim and bright light receptors, respectively. For example, rod and cone visual pigments couple to distinct variants of the heterotrimeric G protein transducin. However, the role of the structural differences between rod and cone transducin α subunits (Tα) in determining the functional differences between rods and cones is unknown. To address this question, we studied the translocation and signaling properties of rod Tα expressed in cones and cone Tα expressed in rods in three mouse strains: rod Tα knockout, cone Tα

GNAT2
cpfl3

mutant, and rod and cone Tα double mutant
rd17
mouse. Surprisingly, although the rod/cone Tα are only 79% identical, exogenously expressed rod or cone Tα localized and translocated identically to endogenous Tα in each photoreceptor type. Moreover, exogenously expressed rod or cone Tα rescued electroretinogram responses (ERGs) in mice lacking functional cone or rod Tα, respectively. Ex vivo transretinal ERG and single-cell recordings from
rd17
retinas treated with rod or cone Tα showed comparable rod sensitivity and response kinetics. These results demonstrate that cone Tα forms a functional heterotrimeric G protein complex in rods and that rod and cone Tα couple equally well to the rod phototransduction cascade. Thus, rod and cone transducin α-subunits are functionally interchangeable and their signaling properties do not contribute to the intrinsic light sensitivity differences between rods and cones. Additionally, the technology used here could be adapted for any such homologue swap desired.
CD4+T cells control the differentiation of Gr1+monocytes into fibrocytes
Authors: Niedermeier Marianne , Reich Barbara , Gomez Manuel Rodriguez , Denzel Andrea , Schmidbauer Kathrin , Göbel Nicole , Talke Yvonne , Schweda Frank , Mack Matthias
Published: October 2009

Fibrocytes are collagen-type-I-producing cells that arise at low frequency from hematopoietic cells. We have analyzed in mice which leukocyte subsets are required for generation of fibrocytes and show that murine fibrocytes develop from the subpopulation of CD11b+CD115+Gr1+monocytes under the control of CD4+T cells. In the absence of CD4+T cells, differentiation of fibrocytes was markedly reduced in vitro and in vivo. In the presence of CD4+T cells, the characteristics of T-cell activation critically determined development of fibrocytes. Polyclonal activation of CD4+T cells induced the release of soluble factors that completely prevented the outgrowth of fibrocytes and could be identified as IL-2, TNF, IFN-γ, and IL-4. Application of IL-2 and TNF significantly reduced the appearance of fibrocytes and the severity of fibrosis in the model of unilateral ureteral obstruction. In contrast, activation of CD4+T cells in the presence of calcineurin inhibitors, but not mTOR inhibitors, markedly enhanced the outgrowth of fibrocytes and renal deposition of collagen I. Taken together, we show that differentiation of fibrocytes is critically dependent on CD4+T cells and that the context of T-cell activation determines whether development of fibrocytes is supported or blocked. Our data may have implications for prevention of organ fibrosis in autoimmune diseases and transplantation.
Structural imperatives impose diverse evolutionary constraints on helical membrane proteins
Authors: Oberai Amit , Joh Nathan H. , Pettit Frank K. , Bowie James U.
Published: October 2009

The amino acid sequences of transmembrane regions of helical membrane proteins are highly constrained, diverging at slower rates than their extramembrane regions and than water-soluble proteins. Moreover, helical membrane proteins seem to fall into fewer families than water-soluble proteins. The reason for the differential restrictions on sequence remains unexplained. Here, we show that the evolution of transmembrane regions is slowed by a previously unrecognized structural constraint: Transmembrane regions bury more residues than extramembrane regions and soluble proteins. This fundamental feature of membrane protein structure is an important contributor to the differences in evolutionary rate and to an increased susceptibility of the transmembrane regions to disease-causing single-nucleotide polymorphisms.