bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in olfactory function in pregnancy and postpartum
Authors: Ochsenbein‐Kölble N. , von Mering R. , Zimmermann R. , Hummel T.
Published: March 2007

Objective: To track changes in olfactory performance during pregnancy and the postpartum. Methods: In a prospective study the olfactory function of 38 pregnant women was assessed at about 12, 21, and 36 weeks of pregnancy and 7 weeks after delivery. A control group of 46 nonpregnant women were also asked to rate the intensity and hedonic tone of 10 “natural” odors. Results: There was no difference in olfactory performance between the women in the first trimester of pregnancy and the controls, but at approximately 36 weeks of pregnancy the pregnant women experienced a decreased odor threshold compared with the nonpregnant controls, and this decrease was still present after delivery. There was no significant difference between the groups in capacity for odor discrimination or odor identification. “Objective” decreases were observed even though pregnant women rated their olfactory sensitivity significantly higher than the controls. Although the 2 groups did not differ with regard to intensity ratings of the 10 “natural” odors, there were differences with regard to the hedonic ratings. Conclusion: Pregnancy is accompanied by changes in olfactory performance. Changes in hedonic odor ratings indicate a potential embryo‐protective mechanism. The discrepancy between “objective” and “subjective” olfactory function may relate to changes in the cognitive processing of chemosensory information during pregnancy.
SCAPHOID BONE BRUISING – PROBABLY NOT THE PRECURSOR OF ASYMPTOMATIC NON-UNION OF THE SCAPHOID
Authors: LA HEI N. , MCFADYEN I. , BROCK M. , FIELD J.
Published: March 2007

The MRI finding of bone marrow oedema, without fracture, following trauma to the scaphoid has been called a ‘bone bruise’. A similar injury is found in the knee, considered benign and managed conservatively. In the scaphoid, there is the concern that this lesion may lead to scaphoid non-union. This study addresses that concern. The clinical and radiological findings of 41 patients with a scaphoid bone bruise on MRI are described, an MRI classification system proposed and clinical outcomes investigated. Patients were immobilised for 6 weeks. At 3 months, 8 remained symptomatic and had repeat MRI. Four of these showed complete resolution of the bruise, the others improvement. At 6 months, 2 of the 8 complained of minor, intermittent discomfort but progressed to resolution of symptoms. This study suggests that the scaphoid bone bruise is a benign injury with predictable recovery and is unlikely to result in long-term morbidity in the form of non-union.
THE ‘METACARPAL CASCADE LINES’; USE IN THE DIAGNOSIS OF DISLOCATIONS OF THE CARPOMETACARPAL JOINTS
Authors: HODGSON P. D. , SHEWRING D. J.
Published: March 2007

Dislocations of the carpometacarpal joints of the ring and little fingers are common and are frequently missed at presentation. We describe a radiographic observation which assists in the confirmation of the diagnosis.
THE EFFECT OF THE SEVERITY OF THE DUPUYTREN’S CONTRACTURE ON THE FUNCTION OF THE HAND BEFORE AND AFTER SURGERY
Authors: ZYLUK A. , JAGIELSKI W.
Published: March 2007

This study investigated the effect on the power and function of the hand of loss of finger(s) extension, number of fingers involved and the patient’s age in Dupuytren’s disease and the influence of improvement of finger extension and the patient’s age on these variables after surgery. Median values at presentation included total loss of extension 80° total grip strength 41 kg and DASH score 54. Twelve months postoperatively, the median value of total loss of extension decreased to 10°and the DASH score to 32 (both significant improvements). Grip strength decreased slightly to 40 kg. The severity of the contracture had no significant effect on function but had a significant negative effect on power. The number of fingers involved affected neither function nor power. The age of the patient did not influence function of the hand. However, older patients experienced less functional benefit from surgery. The improvement of finger extension following surgery had significant beneficial effect on function, but no effect on power.
Quantifying climatic change through the last glacial–interglacial transition based on lake isotope palaeohydrology from central Turkey
Authors: Jones Matthew D. , Roberts C. Neil , Leng Melanie J.
Published: March 2007

Questions remain as to the nature of climatic change through the last glacial–interglacial transition in the eastern Mediterranean region, particularly the relative contribution of evaporation and precipitation to regional water balance. Here changes in oxygen isotope values through this time period from Eski Acıgöl, a crater lake in central Turkey, are investigated using hydrological and isotope mass balance models. These allow changes in evaporation and precipitation to be quantified and their relative importance evaluated. We show that it is the volumetric flux rate of water passing through the lake system and not the precipitation-to-evaporation ratio per se which controlled the stable isotope record in Eski Acıgöl. Early Holocene precipitation is shown to be much greater than that during both the latter part of the last glaciation and the present day. We test these calculated values against other records in the same region, firstly with other lake records in Anatolia, the Konya basin and Lake Van, and secondly with isotope-inferred palaeo-precipitation data from Soreq cave in Israel. This reveals a contrast between pre- and post-LGM precipitation values in Turkey (wetter and drier, respectively) and also suggests that during the last glacial–interglacial transition there was a more marked precipitation gradient than at present between northern/interior and southern/coastal parts of the eastern Mediterranean region.
Editorial
Authors: Stone Roger , Sivakumar M. V. K. , Burt Peter
Published: March 2007

No Absract.
Dissemination and communication of agrometeorological information—global perspectives
Authors: Sivakumar M. V. K.
Published: March 2007

Agrometeorological information and services from the National Meteorological and Hydrological Services (NMHSs) are increasingly being demanded by the farming community to cope more efficiently with climate variability and the increasing incidence of extreme meteorological events such as droughts, floods, frosts and wind erosion. While considerable advances have been made in the collection, archiving and analysis of weather and climate data, their transformation into information that can be readily used by the farm sector has lagged behind, especially in developing countries where such information needs are the greatest. One of the important reasons is the lack of adequate interaction with the user community in assessing the appropriate dissemination and communication procedures that can enhance the value of the agrometeorological information and services. A brief review of the present status of dissemination and communication of agrometeorological information by the NMHSs and associated agencies in different regions around the world is presented. A description of the user communities for agrometeorological information and their varying needs is also presented. Opportunities and challenges in the dissemination and communication of agrometeorological information by the NMHSs are described with suitable examples which emphasize that continued improvements are necessary to make agrometeorological information more accessible and useful to the user community. Copyright © 2006 Royal Meteorological Society
World agrometerological information service (WAMIS)
Authors: Stefanski Robert , Sivakumar M. V. K.
Published: March 2007

During an Inter‐Regional Workshop on Improving Agrometeorological Bulletins in Barbados in October 2001, participants recommended that a dedicated web server be developed for distributing agrometeorological products from WMO members. Subsequently, an Expert Group Meeting on Internet Applications for Agrometeorological Products was held in Washington, DC, during May 2002, to discuss the practical steps needed to develop this web server. Discussions from this meeting led to the development of the World AgroMeteorological Information Service (WAMIS). WAMIS is a dedicated web server on which countries and organisations can place their agrometeorological bulletins and advisories. Provision of such a central location for agrometeorological information enables users to quickly and easily evaluate various bulletins and gain insight into improving their own bulletins. Also, these bulletins represent the expert knowledge of the individual countries and provide the possibility to assess extreme events and disasters in a historical perspective, especially when an archive of bulletins is present. Placement of agrometeorological bulletins on WAMIS also increases the visibility of the National Meteorological/Hydrological Services (NMHS). In March 2005, a tools and resources section was added to WAMIS to provide users with additional papers, links to software tools, Internet links, and other resources to help improving their agrometeorological bulletins and advisories and services. Copyright © 2006 Royal Meteorological Society
Weather and climate monitoring for food risk management
Authors: Maracchi Giampiero , Capecchi Valerio , Marta Anna Dalla , Orlandini Simone
Published: March 2007

Food insecurity represents one of the main indicators of the poverty level of a country and can breed a strong dependence on foreign aid with a strong slowdown of the national economy. African arid and semi‐arid areas are characterised by food precariousness and their agricultural activity is strongly dependent on the extreme climatic conditions that affect the available water supply. This situation has led to the need to develop new tools for the prediction and the management of crisis. The characterisation of climate and the identification of anomalies, the monitoring of weather conditions and their influence on crops, short and medium range weather forecasts and long‐term climate predictions are among the most powerful tools to predict, in as short a time as possible, crises due to the absence or delay of rainfall season. Meteorological information can also be used as an input to agrometeorological models applied for crisis prevention or for its management during the growing season when the crops are already present. In this paper, a review of these tools is made and some operational products presented. Copyright © 2006 Royal Meteorological Society
Commission 8: Astrometry
Authors: Platais Imants , Kumkova Irina I. , Costa E. , Ducourant C. , Evans D. W. , Jin W.-J. , Lattanzi M. G. , Lu C.-L. , Scholz R.-D. , Sôma M.
Published: March 2007

This triennial report from Commission 8 covers astrometry-related matters for objects ranging from Solar system bodies out to Milky Way stars and QSOs at cosmological distances. This enormous range of distances is needed to establish, maintain, and improve the metric of the visible Universe--a very challenging effort since everything is moving. The progress of astrometry in the last three years (2002-2005) is reflected here. To locate the references, the reader is advised to check the NASA ADS Astronomy Abstract Service and the expanded report posted at URL http://www.pha.jhu.edu/iau_comm8/comm8.html
Division I Working Group on Future Development of Ground-Based Astrometry
Authors: Stavinschi Magda
Published: March 2007

The working group “The Future Development of Ground-Based Astrometry” of the IAU Division 1, founded in 2000, continued its activity for the last triennium. Part of its results—meetings or programs—are presented here. The FDGBA web site is http://www.astro.ro/wg
Division I Working Group on “Definition of Coordinated Universal Time”
Authors: Dennis Dennis , McCarthy D. , Arias F. , Dick W. , Gambis D. , Hosokawa M. , Klepczynski W. , Leschiutta S. , Laverty J. , Malkin Z. , Matsakis D. , Nelson R. , Vondrak J. , Wallace P. , Capitaine N. , Fukushima T.
Published: March 2007

The definition of UTC was implemented in 1972, principally to accommodate celestial navigation and follows recommendation 460 of the International Radio Consultative Committee (CCIR) in 1970. Since 1972 the use of electronic means to navigate has overtaken celestial navigation. This fact along with increasing public dissatisfaction with the possible disruption to modern electronic communications and navigation systems caused by the insertion of a leap second has called into question the current definition of UTC. An extensive review of the background and issues relating to the leap second can be found in Nelson, et al (2001).
Division I Working Group on “Precession and the Ecliptic”
Authors: Hilton James L. , Capitaine N. , Chapront J. , Ferrandiz J.M. , Fienga A. , Fukushima T. , Getino J. , Mathews P. , Simon J.-L. , Soffel M. , Vondrak J. , Wallace P. , Williams J.
Published: March 2007

The WG has conferred via email on the topics of providing a precession theory dynamically consistent with the IAU 2000A nutation theory and updating the expressions defining the ecliptic. The consensus of the WG is to recommend:

(a) The terms lunisolar precession and planetary precession be replaced by precession of the equator and precession of the ecliptic, respectively.

(b) The IAU adopt the P03 precession theory, of Capitaine et al (2003a, A& A 412, 567–586) for the precession of the equator (Eqs. 37) and the precession of the ecliptic (Eqs. 38); the same paper provides the polynomial developments for the P03 primary angles and a number of derived quantities for use in both the equinox based and celestial intermediate origin based paradigms.

(c) The choice of precession parameters be left to the user.

(d) The recommended polynomial coefficients for a number of precession angles are given in Table 1 of the WG report, including the P03 expressions set out in Tables 3–;5 of Capitaine et al (2005, A& A 432, 355–;367), and those of the alternative Fukushima (2003, AJ 126, 494–;534) parameterization; the corresponding matrix representations are given in equations 1, 6, 11, and 22 of the WG report.

(e) The ecliptic pole should be explicitly defined by the mean orbital angular momentum vector of the Earth-Moon barycenter in an inertial reference frame, and this definition should be explicitly stated to avoid confusion with older definitions. The formal WG report will be submitted, shortly to Celest. Mech. for publication and their recommendations will be submitted at the next General Assembly for adoption by the IAU.
Commission 12: Solar Radiation & Structure
Authors: Bogdan Thomas. J. , Pillet Valentin Martínez , Asplund M. , Christensen-Dalsgaard J. , Cauzzi G. , Cram L. E. , Dravins D. , Gan W. , Henzl P. , Kosovichev A. , Mariska J. T. , Rovira M. G. , Venkatakrishnan P.
Published: March 2007

Commission 12 covers research on the internal structure and dynamics of the Sun, the “quiet” solar atmosphere, solar radiation and its variability, and the nature of relatively stable magnetic structures like sunspots, faculae and the magnetic network. There is considerable productive overlap with the other Commissions of Division II as investigations move progressively toward the fertile intellectual boundaries between traditional research disciplines. In large part, the solar magnetic field provides the linkage that connects these diverse themes. The same magnetic field that produces the more subtle variations of solar structure and radiative output over the 11 yr activity cycle is also implicated in rapid and often violent phenomena such as flares, coronal mass ejections, prominence eruptions, and episodes of sporadic magnetic reconnection.

The last three years have again brought significant progress in nearly all the research endeavors touched upon by the interests of Commission 12. The underlying causes for this success remain the same: sustained advances in computing capabilities coupled with diverse observations with increasing levels of spatial, temporal and spectral resolution. It is all but impossible to deal with these many advances here in anything except a cursory and selective fashion. Thankfully, theLiving Reviews in Solar Physicsacute; has published several extensive reviews over the last two years that deal explicitly with issues relevant to the purview of Commission 12. The reader who is eager for a deeper and more complete understanding of some of these advances is directed tohttp://www.livingreviews.orgfor access to these articles.
Commission 49: Interplanetary Plasma and Heliosphere
Authors: Webb David F. , Bougeret Jean-Louis , Cane Hilary V. , Cramer Neil F. , Kahler Stephen W. , Kojima Masayoshi , Sanahuja Blai , Vandas Marek , Verheest Frank , von Steiger Rudolf
Published: March 2007

Commission 49 covers research on the solar wind, shocks and particle acceleration, both transient and steady-state, e.g., corotating, structures within the heliosphere, and the termination shock and boundary of the heliosphere. During the last three years there was considerable progress made in studies of solar energetic particles, compositional and other signatures in the heliosphere, solar wind pickup ions, the termination shock, which was finally crossed by a spacecraft, and the boundary between the heliosphere and interstellar medium, and in solar wind modeling and space weather. These topics have been summarized here in five articles, each with extensive references that will guide the reader who wants further details. Observations from the following spacecraft have extensively used during this period: Ulysses, Cassini, Voyager 1 and 2, MESSENGER, ACE, Genesis, SOHO, Wind, and RHESSI.
Commission 51: Bioastronomy – Search for Extraterrestrial Life
Authors: Meech Karen , Boss Alan , Cosmovici Cristiano , Ehrenfreund Pascale , Latham David , Morrison David , Udry Stephane
Published: March 2007

Historically, there have been two main groups dealing with the investigation of extraterrestrial life and habitable worlds. The first is IAU Commission 51, composed of astronomers, physicists and engineers who focus on the search for extrasolar planets, formation and evolution of planetary systems, and the astronomical search for intelligent signals. The second group, the International Society for the Study of the Origin of Life (ISSOL), is composed largely of biologists and chemists focusing research on the biogenesis and evolution of life on Earth and in the solar system. There are now a variety of international organizations dedicated to this field, and this triennium has seen the beginnings of coordination and interaction between the groups through the Federation of Astrobiology Organizations, FAO.
Committee for Small Body Nomenclature
Authors: Kilmartin Pam M. , Tichá Jana , A'Hearn M. F. , Aksnes K. , Fernández J. , Kilmartin P. M. , Kozai Y. , Lazzaro D. , Marsden B. G. , Schmadel L. D. , Shor V. A. , Tichá J. , West R. M. , Williams G. V. , Williams I. P. , Yeomans D. K. , Zhu J. , Green D. W. E.
Published: March 2007

As for comets 619 comets received names from July 2002 to June 2005. Of this naming 76 percent are SOHO comets and 11 percent include the name of the LINEAR project. A revision of the guidelines for naming comets has been completed in March 2003. The assistance of the director of CBAT, Daniel W. E. Green, in redrafting these guidelines was much appreciated by the committee.
Working Group on Planetary Systems Nomenclature (WGPSN)
Authors: Aksnes Kaare Aksnes , Blue J. , Blunck J. , Burba G.A. , Consolmagno G. , Marov M. Ya. , Marsden B.G. , Owen T.C. , Robinson M. , Shevchenko V.V. , Schulz R. , Smith B.A. , Williams I. P.
Published: March 2007

Since the IAU General Assembly in Sydney in July 2003, the WGPSN has conducted its business through numerous e-mail exchanges between the members. A nomenclature workshop was held at Hardingasete, western Norway on September 1–3, 2005. That meeting was attended by eight members from the WG and two from the Task Groups (TG) for the small bodies and for the outer solar system. Input to the meeting had also been received by e-mail from other members.
Working Group on Cartographic Coordinates and Rotational Elements
Authors: Seidelman Kennet P. , A'HEARN M.F. , CRUIKSHANK D.P. , HILTON J.L. , KELLER H.U. , OBERST R J. , SIMON J.L. , STOOKE P. , THOLEN D.J. , THOMAS P.C.
Published: March 2007

The 2003 report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements has appeared in Celestial Mechanics and Dynamical Astronomy(2005)volume 91, part 3–4, pages 203–215. The Working Group continues to maintain and update the information for cartographic coordinates and rotational elements for the Sun, Moon, planets, satellites, asteroids, and comets. A report is published treannually. A web site is maintained at http://extranet.astrogeology.wr.usgs.gov/Projects/WGCCRE with the up-to-date information. It is anticipated that the next report will include updates for Saturn (rotation rate) and all of the Saturnian moons, additions for the newly visited comets and asteroids, and a clarification of the Moon's coordinate systems (the mean Earth/polar axis system needs to be defined more precisely).
Working Group on Abundances in Red Giants
Authors: Lattanzio John C. , Denissenkov Pavel , Gallino Roberto , Hron Josef , Jørgensen Uffe Graae , Kahane Claudine , Kwok Sun , Smith Verne , Tout Christopher , Wing Robert F. , Zinner Ernst
Published: March 2007

Determining and understanding the abundances seen in red-giant stars has taken a central role in our understanding of many branches of modern astrophysics. Activity in the area continues apace, both in terms of the fundamental physics of the stellar nucleosynthesis as well as its implications for wider fields. A major role of the Working Group has been to facilitate meetings where the fundamental role of these stars can be further understood and exploited by other researchers.
Division V: Variable Stars
Authors: Christensen-Dalsgaard Jørgen , Aerts Conny , Giménez Alvaro , Guinan Edward F. , Balona Luis A. , Sahade Jorge
Published: March 2007

Division V, “Variable Stars”, consists of Commission 27, also called “Variable Stars” and Commission 42, “Close Binaries”. Thus the former deals with stars whose variations are intrinsic, whereas in the latter the variations are caused by the interactions between the components in the binary. It is evident that the definition of the Division is predominantly observational, and there may be cases where the assignment of an object to one of the two commissions might be in doubt (a recent somewhat related example was the first detection of an extra-solar planet, in 54 Pegasi, where intrinsic variability of the star in the form of high-order g modes was also initially suspected).
Division VI: Interstellar Matter
Authors: Dyson John , Millar Tom , Chu You-Hua , Ferland Gary , Franco Pepe , Hua Trung , Lizano Susana , Natta Antonella , Reipurth Bo , Sofue Yoshiaki , Stasinska Grazyna , Vilchez Jos
Published: March 2007

Commission 34 covers diffuse matter in space on scales ranging from the circumstellar to the galactic and intergalactic. As such it has enormous scope and because of this, it alone forms Division VI. Key aspects include star formation, matter around evolved stars, astrochemistry, nebulae, galactic and intergalactic clouds and the multitude of effects of the interaction of stars with their surroundings. Associated with these areas are a huge range of physical and chemical processes including hydrodynamics and magnetohydrodynamics, radiative processes, molecular physics and chemistry, plasma processes and others too numerous to name. These are complemented by an equally huge range of observational studies using practically all space and ground-based instrumentation at nearly all observable wavelengths. A glance at any data-base of publications over the past few years attests to the vigorous state of these studies. The current membership of the Division is around 800. It also has three separate working groups.
Division VII: Galactic System
Authors: Whitelock Patricia , Sarajedini Ata , Gerhard Ortwin , Giersz Mirek , Meylan Georges , Nordström Birgitta , Spergel David , Spurzem Rainer
Published: March 2007

The interests of Division VII encompass the Milky Way Galaxy and it comprises two commissions: 33–Structure and Dynamics of the Galactic System and 37–Star Clusters and Association.
Commission 47: Cosmology
Authors: Lilly Simon , Webster Rachel L. , Campusano L. , Charlot S. , DaCosta L. , Koo D. , Lahav O. , LeFevre O. , Padmanabhan T. , Peacock J. , Suto Y. , Scott D.
Published: March 2007

2002–2005 has seen rapid progress in cosmology with the publication of the 1st year WMAP results and analyses of large scale red-shift surveys, ushering in an era of “precision cosmology”. There has been steady progress, too, in the discovery and study of quasars and galaxies in the early Universe.
Division IX: Optical and Infrared Techniques
Authors: Sterken Christiaan , Hearnshaw John B. , Cullum Martin , Dennefeldt Michel , Kudritzki Rolf Peter , Landolt Arlo U. , Lawson Peter R. , Martinez Peter , Nordstrom Birgitta , Ding-qiang Su , Tokovinin Andrei , Udry Stephane
Published: March 2007

This document introduces the reports by the Commissions and Working Groups of Division IX.
Commission 25: Stellar Photometry and Polarimetry
Authors: Landolt A. U. , Martinez P. , Bastien P. , Fabrika S. , Gilliland R. , Grundahl F. , Jordi C. , Munari U.
Published: March 2007

Even a brief glance at astronomical journals indicates the breadth and depth of observational projects making use of photometric and polarimetric techniques. Examples of ongoing photometric and polarimetric research as related by Commission Members follows. I thank the Commission Members, acknowledged below, for their input.
Commission 44: Space & High Energy Astrophysics
Authors: Okuda Haruyuki , Hasinger Gunther , Arnaud M. D. , Bludman S. , Braga J. , Brosch N. , Gurvits L. , Hasan H. , Helou G. , Howarth I. , Inoue H. , Luigi P. , Srinivasan G.
Published: March 2007

Division XI was born by merging Commission 44 “Space and High Energy Astrophysics” and Commission 48 “High Energy Astrophysics” by the decision at the IAU General Assembly in The Hague (1994). As the naming of space astronomy is technique oriented, i.e. astronomy from space, it covers quite a wide range of astronomy, almost all branches of astronomy are included by the progress of space observations. Historically, it started from high energy astronomy, UV, X, and gamma rays astronomy, somewhat including cosmic ray physics. However, in these days, space observations have expanded to low energy astronomy, such as optical, infrared, submillimeter and even radio waves(Space VLBI).
COMMISSION 5: Documentation and Astronomical Data
Authors: Genova Françoise , Norris Raymond P. , Bessel M.S. , Dluzhnevskaia O. , Jenkner H. , Malkov O. , Murtagh F. , Nakajima K. , Ochsenbein F. , Pence W. , Schmitz M. , Wielen R. , Zhao Y.H.
Published: March 2007

The triennial report of Commission V Documentation and Astronomical Data/Documentation et Données Astronomiques covers 2002–2005 activities, and in particular the activities of the five Working Groups: Working Group Astronomical Data; Working Group Designations; Working Group Libraries; Working Group FITS; Working Group Virtual Observatories; and of Task Force for the Preservation and Digitization of Photographic Plates.
Commission 6: Astronomical Telegrams†
Authors: Aksnes Kaare , Gilmore Alan C. , Green D.W.E. , Marsden B.G. , Nakano S. , Roemer E. , Samus N.N. , Tichá J. , Green D.W.E. , Williams G.V.
Published: March 2007

As is evident from Director Dan Green's detailed report below, the Central Bureau for Astronomical Telegrams (CBAT) continues to function in a very reliable and efficient way. The electronic telegrams (CBETs) introduced in 2002 have proved to be a great success; they allow for very rapid dissemination of more extensive information than there is room for on printed Circulars, and they are frequently cited in the astronomical literature. The workload on the Director seems to be forever increasing. It is therefore gratifying that an Assistant Director, Gareth Williams, has been appointed. Since he also serves as Associate Director of the Minor Planet Center (MPC) and performs many of the computations on which the CBETs and the Circulars are based, the ties and mutual benefits between the CBAT and the MPC have been made even stronger.
Commission 50: Protection of Existing and Potential Observatory Sites
Authors: Smith Malcolm G. , Storey Michelle , Cohen Jim , Blanco Carlo , Crawford Dave , Isobe Syuzo , Metaxa Margarita , Sullivan Woody
Published: March 2007

Significant and specific progress has been made in protecting major astronomical sites during the last three years. A brief summary is given, along with references to some of the efforts by members of Commission 50 to control light pollution and radio-frequency interference.
Program Group on International Schools for Young Astronomers
Authors: Gerbaldi Michèle , Guinan Ed
Published: March 2007

In the last triennium two International Schools for Young Astronomers took place in 2004 and 2005, respectively in Morocco and Mexico.
Commission 46: Program Group for the World-Wide Development of Astronomy
Authors: Hearnshaw John , Wentzel Don , Batten Alan , Malasan Hakim , White Jay , Hemenway Mary Kay , Kozai Yoshihide , Alsabti Athem , Martinez Peter , Gray Richard , Narlikar Jayant , Fierro Julieta , Levato Hugo
Published: March 2007

The Program Group for the World-wide Development of Astronomy (PGWWDA) is one of nine Comm. 46 program groups engaged with various aspects of astronomical education or development of astronomy education and research in the developing world. In the case of PGWWDA, its goals are to promote astronomy education and research in the developing world through a variety of activities, including visiting astronomers in developing countries and interacting with them by way of giving encouragement and support.
Valley splitting in strained silicon quantum wells modeled with 2° miscuts, step disorder, and alloy disorder
Authors: Kharche Neerav , Prada Marta , Boykin Timothy B. , Klimeck Gerhard
Published: March 2007

Valley splitting (VS) in strained SiGe∕Si∕SiGe quantum wells grown on (001) and 2° miscut substrates is computed in a magnetic field. Calculations of flat structures significantly overestimate, while calculations of perfectly ordered structures underestimate experimentally observed VS. Step disorder and confinement alloy disorder raise the VS to the experimentally observed levels. Atomistic alloy disorder is identified as the critical physics, which cannot be modeled with analytical effective mass theory. NEMO-3D is used to simulate up to 106 atoms, where strain is computed in the valence-force field and electronic structure in the sp3d5s* model.
Properties of epitaxial GaN on refractory metal substrates
Authors: Freitas Jaime A. , Rowland Larry B. , Kim Jihyun , Fatemi Mohammad
Published: March 2007

The authors demonstrate here that GaN films with good surface morphology and structural, optical, and electronic properties can be grown on metallic titanium carbide substrates. X-ray rocking curve and Raman scattering measurements confirmed the high crystalline quality of the wurtzite structure film. Variable temperature photoluminescence measurements of sharp and intense emission lines provided insights into the nature of the recombination processes, the carrier background type, and the carrier concentration. The high quality of the interface and substrate Ohmic contacts was verified. The ability to grow high-quality films on metallic substrates provides the means for advanced vertical and high-power and/or high-temperature device fabrication.
Resonant crystal band gap metamaterials in the microwave regime and their exotic amplification of evanescent waves
Authors: Liu Ruopeng , Cui Tie Jun , Zhao Bo , Lin Xian Qi , Ma Hui Feng , Huang Da , Smith David R.
Published: March 2007

The authors realize resonant crystal band gap metamaterials (CBMs) using circuit structures in the microwave regime, which behave quite differently from the conventional photonic band gap structures. They show that a periodic array of series inductor and shunt capacitor is equivalent to a CBM similar to a magnetic plasma at higher frequency band, and a periodic array of series capacitor and shunt inductor behaves like a CBM similar to an electric plasma at lower frequency band. The equivalent medium parameters have been derived in both cases, which show the existence of conjugate loss in imaginary parts. When two such structures are cascaded together, the authors demonstrate that evanescent waves are amplified and transmitted in a very narrow frequency band under the antimatching condition. Such a feature can be used to design extremely narrow band filters. Theoretical predictions, circuit simulations, and experimental results are presented to validate their conclusions.
Near-field second harmonic generation by using uncoated silicon tips
Authors: Breit M. , Malkmus S. , Feldmann J. , Danzebrink H. U.
Published: March 2007

The authors present a concept of a scanning near-field optical microscope for second harmonic imaging. The microscope is based on uncoated silicon atomic force microscope tips, which provide high intensity transmission in the midinfrared spectral range. An approximately three times larger contrast was found for the second harmonic compared to the linear signal. By using a lithographically designed sample of an array of gold nanoparticles the capability of imaging structures much smaller than the fundamental and second harmonic wavelength is demonstrated.
Evidence of cascaded emission in a dual-wavelength quantum cascade laser
Authors: Franz Kale J. , Wasserman Daniel , Hoffman Anthony J. , Jangraw David C. , Shiu Kuen-Ting , Forrest Stephen R. , Gmachl Claire
Published: March 2007

This letter reports on a quantum cascade laser that exhibits simultaneous dual-wavelength emission from two consecutive optical transitions in each active region. These “cascaded” transitions—a second-excited state to first-excited state and a first-excited state to ground state—yield light at ∼9.5 and ∼8.2μm, respectively, in good agreement with simulations. The two lasing wavelengths have similar thresholds at the leading edge of a current pulse.
Using the excitation-dependent radiative efficiency to assess asymmetry in the defect-related density of states
Authors: Topaz A. , West B. A. , Gfroerer T. H. , Wanlass M. W.
Published: March 2007

Measurements of steady-state radiative efficiency versus photoexcitation rate probe the carrier-density-dependent competition between nonradiative and radiative mechanisms in semiconductors. Nonradiative recombination through defect levels is proportional to the product of defect level occupation and carrier density in the opposing band. Band-to-band radiative recombination scales with the product of band densities. The excitation rate required for defect level saturation establishes the effective density of participating defects. More subtle features in the changeover from defect-related to radiative-dominated recombination, and its temperature dependence, provide additional insight into the distribution of defect levels. In this letter, the authors consider the effect of asymmetry about the midgap.
Ultrathin low temperature SiGe buffer for the growth of high quality Ge epilayer on Si(100) by ultrahigh vacuum chemical vapor deposition
Authors: Loh T. H. , Nguyen H. S. , Tung C. H. , Trigg A. D. , Lo G. Q. , Balasubramanian N. , Kwong D. L. , Tripathy S.
Published: March 2007

The authors report a method to grow high quality strain-relaxed Ge on a combination of low-temperature Ge seed layer on low temperature ultrathin Si0.8Ge0.2 buffer with thickness of 27.3nm by ultrahigh vacuum/chemical-vapor-deposition method without the need to use chemical mechanical polish or high temperature annealing. On 8in. Si wafer, the etch-pit density was 6×106cm−2. The root-mean-square surface roughnesses of Ge epitaxy by atomic force microscopy were 1.4 and 1.2nm for bulk Si and silicon-on-insulator substrates, respectively. Micro-Raman spectroscopy shows extremely uniform distribution of residual strain in the overgrown Ge epitaxy on 8in. wafers.
High Q, one-dimensional terahertz photonic waveguides
Authors: Bingham A. L. , Grischkowsky D.
Published: March 2007

A one-dimensional (1D) photonic metal parallel plate waveguide is presented in the spectral range of 0.5–3THz that has high throughput and stop bands with up to the experimental limit of 40dB of dynamic range. By incorporating a defect into the periodic bottom plate of the waveguide, a transmission resonance is generated in the first stop band with a Q value of 120 and a dynamic range of over 17dB. The 1D geometry allows the utilization of the mode matching technique to analytically calculate the transmission of the photonic waveguide.
On the mechanism of wing size determination in fly development
Authors: Hufnagel Lars , Teleman Aurelio A. , Rouault Hervé , Cohen Stephen M. , Shraiman Boris I.
Published: March 2007

A fundamental and unresolved problem in animal development is the question of how a growing tissue knows when it has achieved its correct final size. A widely held view suggests that this process is controlled by morphogen gradients, which adapt to tissue size and become flatter as tissue grows, leading eventually to growth arrest. Here, we present evidence that the decapentaplegic (Dpp) morphogen distribution in the developing
Drosophila
wing imaginal disk does not adapt to disk size. We measure the distribution of a functional Dpp-GFP transgene and the Dpp signal transduced by phospho-Mad and show that the characteristic length scale of the Dpp profile remains approximately constant during growth. This finding suggests an alternative scenario of size determination, where disk size is determined relative to the fixed morphogen distribution by a certain threshold level of morphogen required for growth. We propose that when disk boundary reaches the threshold the arrest of cell proliferation throughout the disk is induced by mechanical stress in the tissue. Mechanical stress is expected to arise from the nonuniformity of morphogen distribution that drives growth. This stress, through a negative feedback on growth, can compensate for the nonuniformity of morphogen, achieving uniform growth with the rate that vanishes when disk boundary reaches the threshold. The mechanism is demonstrated through computer simulations of a tissue growth model that identifies the key assumptions and testable predictions. This analysis provides an alternative hypothesis for the size determination process. Novel experimental approaches will be needed to test this model.
Increased genetic variation and evolutionary potential drive the success of an invasive grass
Authors: Lavergne Sébastien , Molofsky Jane
Published: March 2007

Despite the increasing biological and economic impacts of invasive species, little is known about the evolutionary mechanisms that favor geographic range expansion and evolution of invasiveness in introduced species. Here, we focus on the invasive wetland grass
Phalaris arundinacea
L. and document the evolutionary consequences that resulted from multiple and uncontrolled introductions into North America of genetic material native to different European regions. Continental-scale genetic variation occurring in reed canarygrass' European range has been reshuffled and recombined within North American introduced populations, giving rise to a number of novel genotypes. This process alleviated genetic bottlenecks throughout reed canarygrass' introduced range, including in peripheral populations, where depletion of genetic diversity is expected and is observed in the native range. Moreover, reed canarygrass had higher genetic diversity and heritable phenotypic variation in its invasive range relative to its native range. The resulting high evolutionary potential of invasive populations allowed for rapid selection of genotypes with higher vegetative colonization ability and phenotypic plasticity. Our results show that repeated introductions of a single species may inadvertently create harmful invaders with high adaptive potential. Such invasive species may be able to evolve in response to changing climate, allowing them to have increasing impact on native communities and ecosystems in the future. More generally, multiple immigration events may thus trigger future adaptation and geographic spread of a species population by preventing genetic bottlenecks and generating genetic novelties through recombination.
Sox17
is essential for the specification of cardiac mesoderm in embryonic stem cells
Authors: Liu Yu , Asakura Masanori , Inoue Hironori , Nakamura Teruya , Sano Motoaki , Niu Zhiyv , Chen Michelle , Schwartz Robert J. , Schneider Michael D.
Published: March 2007

Early steps for cardiac specification are problematic for the study of mammalian embryos, which has favored using pluripotent cells that recapitulate cardiac myogenesis. Furthermore, circuits governing cardiac specification have relevance to the application of ES cells and other cells for heart repair. In mouse teratocarcinoma cells, canonical Wnts that inhibit heart formation in avian or amphibian embryos and explants activate cardiogenesis, paradoxically. Here, we show that the Wnt/β-catenin pathway also is essential for cardiac myogenesis to occur in ES cells, acting at a gastrulation-like stage, mediating mesoderm formation and patterning (two prerequisites for cardiac myogenesis itself). Among genes associated temporally with this step was
Sox17
, encoding an endodermal HMG-box transcription factor. Using lentiviral vectors for RNA interference in differentiating ES cells, an essential role for
Sox17
was proven in cardiac muscle cell formation.
Sox17
short-hairpin RNA suppresses cardiac myogenesis selectively, acting subsequent to mesoderm formation yet before induction of
Mesp1
and
Mesp2
, a pair of related basic helix–loop–helix transcription factors that together are indispensable for creating heart mesoderm.
Sox17
short-hairpin RNA blocks cardiac myogenesis non-cell autonomously and impairs the induction of Hex, a homeodomain transcription factor that is known to be required for the production of endoderm-derived heart-inducing factors.
HIV-1 Vpr function is mediated by interaction with the damage-specific DNA-binding protein DDB1
Authors: Schröfelbauer Bärbel , Hakata Yoshiyuki , Landau Nathaniel R.
Published: March 2007

The Vpr accessory protein of HIV-1 induces a response similar to that of DNA damage. In cells expressing Vpr, the DNA damage sensing kinase, ATR, is activated, resulting in G
2
arrest and apoptosis. In addition, Vpr causes rapid degradation of the uracil-DNA glycosylases UNG2 and SMUG1. Although several cellular proteins have been reported to bind to Vpr, the mechanism by which Vpr mediates its biological effects is unknown. Using tandem affinity purification and mass spectrometry, we identified a predominant cellular protein that binds to Vpr as the damage-specific DNA-binding protein 1 (DDB1). In addition to its role in the repair of damaged DNA, DDB1 is a component of an E3 ubiquitin ligase that degrades numerous cellular substrates. Interestingly, DDB1 is targeted by specific regulatory proteins of other viruses, including simian virus 5 and hepatitis B. We show that the interaction with DDB1 mediates Vpr-induced apoptosis and UNG2/SMUG1 degradation and impairs the repair of UV-damaged DNA, which could account for G
2
arrest and apoptosis. The interaction with DDB1 may explain several of the diverse biological functions of Vpr and suggests potential roles for Vpr in HIV-1 replication.
Spatial navigation deficit in amnestic mild cognitive impairment
Authors: Hort Jakub , Laczó Jan , Vyhnálek Martin , Bojar Martin , Bureš Jan , Vlček Kamil
Published: March 2007

Patients with Alzheimer's disease (AD) frequently have difficulties with spatial orientation in their day-to-day life. Although AD is typically preceded by amnestic mild cognitive impairment (MCI), spatial navigation has not yet been studied in MCI. Sixty-five patients were divided into five groups: probable AD (
n
= 21); MCI, further classified as amnestic MCI single domain (
n
= 11); amnestic MCI multiple domain (
n
= 18), or nonamnestic MCI (
n
= 7), and subjective memory complaints (
n
= 8). These patients, together with a group of healthy control subjects (
n
= 26), were tested by using a four-subtests task that required them to locate an invisible goal inside a circular arena. Each subtest began with an overhead view of the arena showed on a computer monitor. This was followed by a real navigation inside of the actual space, an enclosed arena 2.9 m in diameter. Depending on the subtest, the subjects could use the starting position and/or cues on the wall for navigation. The subtests thus were focused on allocentric and egocentric navigation. The AD group and amnestic MCI multiple-domain group were impaired in all subtests. The amnestic MCI single-domain group was impaired significantly in subtests focused on allocentric orientation and at the beginning of the real space egocentric subtest, suggesting impaired memory for allocentric and real space configurations. Our results suggest that spatial navigation impairment occurs early in the development of AD and can be used for monitoring of the disease progression or for evaluation of presymptomiatic AD.
Scanning tunneling microscopy of the formation, transformation, and property of oligothiophene self-organizations on graphite and gold surfaces
Authors: Yang Zhi-Yong , Zhang Hui-Min , Yan Cun-Ji , Li Shan-Shan , Yan Hui-Juan , Song Wei-Guo , Wan Li-Jun
Published: March 2007

Two alkyl-substituted dual oligothiophenes, quarterthiophene (4T)-trimethylene (tm)-octithiophene (8T) and 4T-tm-4T, were used to fabricate molecular structures on highly oriented pyrolytic graphite and Au(111) surfaces. The resulted structures were investigated by scanning tunneling microscopy. The 4T-tm-8T and 4T-tm-4T molecules self-organize into long-range ordered structures with linear and/or quasi-hexagonal patterns on highly oriented pyrolytic graphite at ambient temperature. Thermal annealing induced a phase transformation from quasi-hexagonal to linear in 4T-tm-8T adlayer. The molecules adsorbed on Au(111) surface in randomly folded and linear conformation. Based on scanning tunneling microscopy results, the structural models for different self-organizations were proposed. Scanning tunneling spectroscopy measurement showed the electronic property of individual molecules in the patterns. These results are significant in understanding the chemistry of molecular structure, including its formation, transformation, and electronic properties. They also help to fabricate oligothiophene assemblies with desired structures for future molecular devices.