bluuebunny/crossref_metadata_2025 huggingface dataset:
Digesta passage rates in the Florida manatee (Trichechus manatus latirostris)
Authors: Larkin Iskande L.V. , Fowler Vivienne F. , Reep Roger L.
Published: August 2007

The Florida manatee, Trichechus manatus latirostris (Sirenia: Trichechidae), is an herbivorous marine mammal found within coastal areas throughout the state of Florida, which feeds on both fresh and salt water sea grasses. Manatees, like other Sirenians, are a tropical species with little tolerance for water temperatures below 20°C, rely on a relatively poor nutritional food source, and have a low metabolic rate. Although manatees are hindgut fermenting herbivores, they are very efficient at extracting nutrients from the plants on which they feed. Slow passage rates of digesta have been suggested to be a factor in this increased efficiency. Two studies monitored the digesta passage times and mixing of particulate digesta within the manatee digestive tract using MicroGrits colored corncob grit as a fecal marker. Fecal samples were collected subsequently from four manatees in Study 1 and 3 manatees in Study 2, grit pieces removed, counted, and measured. The digesta passage times ranged from 6 and 10 days in Study 1, and 4.3 and 8.3 days in Study 2, supporting data presented in previous studies. When two different colored markers were administered on sequential days, minimal to no mixing was seen in recovered feces, suggesting that the digesta from a given day traveled through the tract as a bolus. Less than 1% of the marker fed was recovered and we hypothesize that perpendicular folds of the large intestine may be the major contributing factor, with pieces being retained and eventually digested. Zoo Biol 26:503–515, 2007. © 2007 Wiley‐Liss, Inc.
Review of contraception in ungulate species
Authors: Patton M.L. , Jöchle W. , Penfold L.M.
Published: August 2007

Most ungulate species are herd animals. In captivity, and increasingly so in the wild, space constraints limit natural behaviors associated with group dynamics, possibly resulting in inbreeding and/or overpopulation. This situation has necessitated research regarding contraception of various species of hoofstock. Differing management situations mandate different contraception protocols to achieve optimal results. Fertility control in hoofstock has been achieved through a number of different contraceptive methods predominantly surgical sterilization, mechanical contraception, synthetic steroid hormones, and immunocontraception. In this study successes and limitations of these techniques are reviewed. Zoo Biol 26:311–326, 2007. © 2007 Wiley‐Liss, Inc.
Treatment of hypertension in children and adolescents
Authors: Lande Marc B. , Flynn Joseph T.
Published: August 2007

The treatment of hypertension in children and adolescents has been markedly changed in recent years by several factors, including the publication of new consensus recommendations, the obesity epidemic, and the increased availability of information on efficacy and safety of antihypertensive medications in the young. In this review we present an updated approach to the outpatient management of hypertension in the child or adolescent, utilizing representative cases to illustrate important principles as well as possible controversies.
Biomechanical Evaluation of Volar Locking Plates for Distal Radius Fractures
Authors: Levin Scott M. , Nelson Cory O. , Botts Jonathan D. , Teplitz Glenn A. , Kwon Yong , Serra-Hsu Fred
Published: August 2007

Purpose Fixed-angle devices have been a major advancement in orthopedic fracture care and have become an attractive option for fixation of distal radius fractures. Several volar locking plates exist, but there is insufficient literature comparing the strengths of these plates. This study compares the biomechanical strength of two popular volar locking plate systems (Synthes LCP and Hand Innovations DVR-A) along with a nonlocking volar T-plate (Synthes).

Methods Twenty-three formalin-fixed cadaveric forearms were divided into three groups with similar ages and bone densities. An unstable extra-articular fracture was created using a standardized osteotomy. Each group was fixed with one of the three plates. Each specimen was loaded in axial compression for 2000 cycles at a force of 400 N. Each specimen that completed cyclic testing was loaded to failure. Stiffness, yield point, and ultimate strength were recorded for each construct.

Results Each fixed-angle construct completed all 2000 cycles. The nonlocking plates failed at an average of 560 cycles. The mean stiffness of the DVR-A, LCP, and the volar T-plates were 277.00, 343.17, and 175.67 N/mm, respectively. There was a statistically significant difference between both fixed-angle plates and the nonlocking plate ( p<0.05). The difference between each fixed-angle construct did not reach significance. Yield point and ultimate strength could only be determined for the two fixed-angle devices. There was no statistically significant difference between the constructs for both yield point (DVR-A=855.56 N, LCP=894.15 N) and ultimate strength (DVR-A=1,021.97 N, LCP=1,114.87 N).

Conclusions Given our data, fixed-angle constructs withstand cyclical loading representing normal physiologic forces encountered during post-operative rehabilitation. There was no significant biomechanical difference between the two fixed-angle constructs. Our results support that volar fixed-angle locking plates are an effective treatment for unstable extra-articular distal radius fractures, allowing early postoperative rehabilitation to safely be initiated.
Aging effects on joint proprioception: the role of physical activity in proprioception preservation
Authors: Ribeiro Fernando , Oliveira José
Published: August 2007

Throughout the human life span the functions of several physiological systems dramatically change, including proprioception. Impaired proprioception leads to less accurate detection of body position changes increasing the risk of fall, and to abnormal joint biomechanics during functional activities so, over a period of time, degenerative joint disease may result. Altered neuromuscular control of the lower limb and consequently poor balance resulting from changes in the proprioceptive function could be related to the high incidence of harmful falls that occur in old age subjects. There is evidence of proprioception deterioration with aging. Regular physical activity seems to be a beneficial strategy to preserve proprioception and prevent falls among older subjects. Some studies have demonstrated that the regular physical activity can attenuate age-related decline in proprioception. This paper reviews the evidence of age effects on joint proprioception. We will discuss the possible mechanisms behind these effects and the role of regular physical activity in the attenuation of age-related decline in proprioception.
Fatty Acid Supplied as Triglyceride Regulates SRE‐Mediated Gene Expression as Efficiently as Free Fatty Acids
Authors: Densupsoontorn Narumon , Worgall Tilla S. , Seo Toru , Hamai Hiroko , Deckelbaum Richard J.
Published: August 2007

Sterol regulatory element binding proteins (SREBPs) are key transcription proteins that bind to sterol regulatory elements (SRE) of genes essential for cellular cholesterol and fatty acid homeostasis. Polyunsaturated fatty acids (PUFA) strongly inhibit SREBP processing at post‐transcriptional levels. We questioned if delivering PUFA as part of a triglyceride (TG) molecule would have similar effects and efficiency as free non‐esterified PUFA. CHO cells stably transfected with an SRE‐promoter linked to the luciferase reporter gene were incubated for 8–24 h with linoleic acid (LA) complexed to BSA (molar ratios 0.5–4:1), VLDL‐sized trilinolein emulsions (TL, 25–200 μg/ml), and chylomicron‐sized soy oil emulsions in the presence and absence of apoE. Effects of LA and TL on decreasing SRE‐luciferase activity were similar and dose and time dependent. Both TL and LA significantly and rapidly (≤2–12 h) reduced SRE‐mediated gene expression by up to 75%. At equal fatty acid concentrations, SRE inhibition by TL was as effective as LA. ApoE addition increased inhibition by TL. Inhibition of gene expression was highly correlated to cell TG accumulation. We conclude that TG like fatty acids are rapid and efficient modulators of SRE‐mediated gene expression.
A Study on Subunit Groups of Soybean Protein Extracts under SDS‐PAGE
Authors: Liu Shunhu , Zhou Ruibao , Tian Shaojun , Gai Junyi
Published: August 2007

Protein extracts of 640 soybean cultivars and landraces, mainly from China and a few from the US, were analyzed for their components and subunits based on distribution patterns of bands with varying molecular weights (MW) under SDS‐PAGE (sodium dodecyl sulfate‐polyacrylamide gel electrophoresis). The number and molecular weight of the bands in SDS‐PAGE varied among materials and showed a tendency of continuous distribution. Accordingly, the SDS‐PAGE patterns of the soybean protein extracts were divided into two regions: the region of bands with MW < 44 KDa and that with MW ≥ 44 KDa. The first region containing mainly 11S proteins was divided into four parts, called subunit groups, i.e. 11S‐1 (14.4–22 KDa), 11S‐2 (22–26 KDa), 11S‐3 (26–34 KDa) and 11S‐4 (34–44 KDa). The second region containing mainly 7S protein was divided into six subunit groups, i.e. 7S‐1 (44–49 KDa), 7S‐2 (49–55 KDa), 7S‐3 (55–67 KDa), 7S‐4 (67–73 KDa), 7S‐5 (73–82 KDa) and 7S‐6 (82–91 KDa). The sum of relative contents of 11S‐1–11S‐4 was obtained as the relative content of 11S protein, those of 7S‐1–7S‐6 as that of 7S protein, and therefore, the 11S/7S ratio obtained. The proposed criteria were demonstrated to be simple, stable and feasible. Among the 640 tested materials, 39 lacked 11S‐1 but none lacked the other 11S subunit groups, while deficiencies existed in all the six subunit groups of 7S, indicating a great potential for the genetic variation of protein components and subunits for breeding for the improvement of protein qualities.
Race, Culture, and Skill: Interracial Wage Differences among African Americans, Latinos, and Whites
Authors: Mason Patrick L.
Published: August 2007

This article examines the interrelationships among race, culture, skill, and the distribution of wages. I utilize a three-equation system to explore this process: skill is a multidimensional productive attribute measured by years of education and work effort; educational attainment is a function of class background and individual effort; and individual wage rates are a function of skill and class background. By further assuming that effort is differentially distributed across individuals and social groups, I am able to estimate reduced form equations for educational and earnings attainment, where both equations are functions of the class backgrounds and race of individuals.

The collective results of this article challenge the conventional wisdom among economists that African American and Latino job skills are of a lower quality than white job skills. To the extent that effort is an important element of worker skill, our results suggest that neither African American nor Latino labor is of lower quality than white labor. The results regarding differences between African Americans and whites in educational attainment, i.e., African Americans are able to translate a given level of resources into higher levels of educational attainment, reaffirm previous findings in the literature. The results on Latino versus white educational attainment are novel. Additionally, unlike previous research, this article connects racial differences in the skill acquisition process to the economics of discrimination.
The Wilder Vote and the New South Phenomenon: A Multivariate Analysis
Authors: Clemons Michael L. , Jones Charles E.
Published: August 2007

This study employed ordinary least-squares (OLS) regression to explore possible linkages between the election of L. Douglas Wilder to the governorship of the Commonwealth of Virginia and the New South phenomenon. Five selected aggregate level indicators reflective of the New South political terrain served as independent variables. The dependent variable of the analysis was the electoral support garnered by Wilder. Four of the independent variables were statistically significant (race, urbanization, income, and industrialization). However, the education variable did not achieve statistical significance. The model yielded an adjusted R2 = .41. The results of our exploratory analysis suggest that the impact of the New South on the Wilder victory was limited, though crucial to his narrow victory. Thus, social and demographic change as suggested by the New South thesis, while important, do not necessarily portend African American statewide electoral success. Further systematic study of this historic contest at the individual level could shed light on political behavior among African American and white voters in the New South.
Black Male Unemployment
Authors: Schwartzman David
Published: August 2007

Public policies intended to raise the wages of unskilled workers, equalize educational opportunity, stabilize employment, and increase imports were sources of the growth of unskilled and, therefore, of black unemployment since 1950. The wartime wage-equalization policy and postwar minimum-wage policies raised the cost of unskilled labor relative to that of capital and of skilled labor. The Fed's inflationary full-employment policy between 1950 and 1970 reduced real interest rates relative to unskilled wages. Subsidies for higher education increased the supply of skilled labor, reducing its cost relative to that of unskilled labor. Trade liberalization increased imports of manufactured goods from developing countries, which displaced U.S. unskilled labor.
Decadal-scale autumn temperature reconstruction back to AD 1580 inferred from the varved sediments of Lake Silvaplana (Southeastern Swiss Alps)
Authors: Blass Alex , Bigler Christian , Grosjean Martin , Sturm Michael
Published: August 2007

A quantitative high-resolution autumn (September–November) temperature reconstruction for the southeastern Swiss Alps back to AD 1580 is presented here. We used the annually resolved biogenic silica (diatoms) flux derived from the accurately dated and annually sampled sediments of Lake Silvaplana (46°27′N, 9°48′E, 1800 m a.s.l.). The biogenic silica flux smoothed by means of a 9-yr running mean was calibrated (r=0.70, p<0.01) against local instrumental temperature data (AD 1864–1949). The resulting reconstruction (± 2 standard errors=±0.7 °C) indicates that autumns during the late Little Ice Age were generally cooler than they were during the 20th century. During the cold anomaly around AD 1600 and during the Maunder Minimum, however, the reconstructed autumn temperatures did not experience strong negative departures from the 20th-century mean. The warmest autumns prior to 1900 occurred around AD 1770 and 1820 (0.75 °C above the 20th-century mean). Our data agree closely with two other autumn temperature reconstructions for the Alps and for Europe that are based on documentary evidence and are completely unrelated to our data, revealing a very consistent picture over the centuries.
LINEAR FRACTIONAL RELATIONS IN BANACH SPACES: INTERIOR POINTS IN THE DOMAIN AND ANALOGUES OF THE LIOUVILLE THEOREM
Authors: OSTROVSKII M. I.
Published: August 2007

In this paper we study linear fractional relations defined in the following way. Let${\cal B}$i,${\cal B}$'i,i= 1,2, be Banach spaces. We denote the space of bounded linear operators by${\cal L}$. LetTε${\cal L}$(${\cal B}$1⊕${\cal B}$2,${\cal B}$'1⊕${\cal B}$'2). To each such operator there corresponds a 2 × 2 operator matrix of the form(*)whereTijε${\cal L}$(${\cal B}$j,${\cal B}$'i. For each suchTwe define a set-valued mapGTfrom${\cal L}$(${\cal B}$1,${\cal B}$2) into the set of closed affine subspaces of${\cal L}$(${\cal B}$'1,${\cal B}$'2) by

The mapGTis called alinear fractional relation.

The paper is devoted to the following two problems.

•

Characterization of operator matrices of the form (*) for which the setGT(K) is non-empty for eachKin some open ball of the space${\cal L}$(${\cal B}$1,${\cal B}$2).

•

Characterizations of quadruples (${\cal B}$1,${\cal B}$2,${\cal B}$'1,${\cal B}$'2) of Banach spaces such that linear fractional relations defined for such spaces satisfy the natural analogue of the Liouville theorem “a bounded entire function is constant”.
STABILITY OF MAPPINGS ON MULTI-NORMED SPACES
Authors: DALES H. G. , MOSLEHIAN MOHAMMAD SAL
Published: August 2007

In this paper, we define multi-normed spaces, and investigate some properties of multi-bounded mappings on multi-normed spaces. Moreover, we prove a generalized Hyers–Ulam–Rassias stability theorem associated to the Cauchy additive equation for mappings from linear spaces into multi-normed spaces.
Non-GPS Navigation for Security Personnel and First Responders
Authors: Ojeda Lauro , Borenstein Johann
Published: August 2007

This paper introduces a “Personal Dead-reckoning” (PDR) navigation system for walking persons. The system is useful for monitoring the position of emergency responders inside buildings, where GPS is unavailable. The PDR system uses a six-axes Inertial Measurement Unit attached to the user's boot. The system's strength lies in the use of a technique known as Zero Velocity Update (ZUPT) that virtually eliminates the ill-effects of drift in the accelerometers. It works very well with different gaits, as well as on stairs, slopes, and generally on 3-dimensional terrain. The paper explains the PDR and presents extensive experimental results, which illustrate the utility and practicality of the system. Parts of this paper were presented at the 2006 International Joint Topical Meeting: “Sharing Solutions for Emergencies and Hazardous Environments,” February 12–15, 2006, Salt Lake City, Utah, USA.
Externalizing tacit overview knowledge: A model-based approach to supporting design teams
Authors: Flanagan Tomás , Eckert Claudia , Clarkson P. John
Published: August 2007

Successful realization of large-scale product development programs is challenging because of complex product and process dependencies and complicated team interactions. Proficient teamwork is underpinned by knowledge of the manner in which tasks performed by different design participants fit together to create an effective whole. Based on an extensive industrial case study with a diesel engine company, this paper first argues that the overview and experience of senior designers play an important part in supporting teamwork by coordinating activities and facilitating proactive communication across large project teams. As experts move on and novices or contractors are hired, problems are likely to occur as tacit overview knowledge is lost. If informal, overview-driven processes break down, the risk of costly oversights will increase, and greater management overhead will be required to realize successful product designs. Existing process models provide a means to express the connectivity between tasks and components thus to compensate partially for the loss of tacit overview. This paper proposes the use of design confidence, a metric that reflects the designer's belief in the maturity of a particular design parameter at a given point in the process, to address the limitations of existing models. The applicability of confidence-based design models in providing overview, as well as their shortcomings, will be demonstrated through the example of a diesel engine design process. Confidence can be used to make overview knowledge explicit and convey additional information about the design artifact, thereby informing communication and negotiation between teams.
Making sense of engineering design review activities
Authors: Huet Gregory , Culley Stephen J. , McMahon Christopher A. , Fortin ClÉment
Published: August 2007

Engineering design reviews, which take place at predetermined phases of the product development process, are fundamental elements for the evaluation and control of engineering activities. These meetings are also acknowledged as unique opportunities for all the parties involved to share information about the product and related engineering processes. For product development teams, the knowledge generated during a design review is not as secondary as it may seem; key design decisions, design experiences, and associated rationale are frequently made explicit. Useful work has been carried out on the design review process itself, but little work has been undertaken about the detailed content of the meeting activity; it is argued that understanding the transactions that take place during a meeting is critical to building an effective knowledge-oriented recording strategy. To this effect, an extensive research program based on case studies in the aerospace engineering domain has been carried out. The work reported in this paper focuses on a set of tools and methods developed to characterize and analyze in depth the transactions observed during a number of case studies. The first methodology developed, the transcript coding scheme, uses an intelligent segmentation of meeting discourse transcriptions. The second approach, which bypasses the time consuming transcribing operation, is based on a meeting capture template developed to enable a meeting observer to record the transactions as the meeting takes place. A third method, the information mapping technique, has also been developed to interpret the case study data in terms of decisions, actions, rationale, and lessons learned, effectively generating qualitative measures of the information lost in the formal records of design reviews. Overall, the results generated by the set of tools presented in this paper have fostered a practical strategy for the knowledge intensive capture of the contents of design reviews. The concluding remarks also discuss possible enhancements to the meeting analysis tools presented in this paper and future work aimed at the development of a computer supported capture software for design reviews.
Collaborative design exploration in an interactive workspace
Authors: Fruchter Renate , Saxena Kushagra , Breidenthal Matt , Demian Peter
Published: August 2007

Architecture, engineering, and construction team members, while collaborating on building projects, rely on past experiences and content through the use of project design archives (whether in paper or digital format). Underutilization of potential knowledge in the decision-making process of data, information, and knowledge reuse is limited by access to these archives, because of sheer size, decontextualized content, and inconvenient access and presentation. This paper presents an integrated solution called CoMem–iRoom that leverages two technologies Corporate Memory (CoMem) and interactive Room (iRoom) developed at Stanford. CoMem–iRoom addresses critical limitations (content, context, visualization, and interactivity) constraining the process of collaborative exploration toward knowledge reuse and decision making.
An ontology of situated design teams
Authors: Gero John S. , Kannengiesser Udo
Published: August 2007

This paper presents an ontological framework for situated design teams in which the team is both the subject and the object of designing. Team designing is modeled using the set of processes provided by the situated function–behavior–structure framework. This is a formal basis for understanding the drivers for change in the product to be designed and in the design team. We specifically focus on changes in a team's structure that emerge from interactions among individual team members and subteams.
Part III. Analysis of data gaps pertaining to enterotoxigenicEscherichia coliinfections in low and medium human development index countries, 1984–2005
Authors: GUPTA S. K. , KECK J. , RAM P. K. , CRUMP J. A. , MILLER M. A. , MINTZ E. D.
Published: August 2007

EnterotoxigenicEscherichia coli(ETEC) is a common cause of profuse watery diarrhoea in the developing world, often leading to severe dehydration or death. We found only 15 population-based studies in low and medium human development index (HDI) countries from 1984 to 2005 that evaluate disease incidence. Reported incidence ranged from 39 to 4460 infections/1000 persons per year. The peak incidence of ETEC appeared to occur between ages 6 and 18 months. A median of 14% (range 2–36%) of diarrhoeal specimens were positive for ETEC in 19 facility- and population-based studies conducted in all age groups and 13% (range 3–39%) in 51 studies conducted in children only. Heat-labile toxin (LT)-ETEC is thought to be less likely to cause disease than heat-stable toxin (ST)-ETEC or LT/ST-ETEC. Because population-based studies involve enhanced clinical management of patients and facility-based studies include only the most severe illnesses, reliable data on complications and mortality from ETEC infections was unavailable. To reduce gaps in the current understanding of ETEC incidence, complications and mortality, large population-based studies combined with facility-based studies covering a majority of the corresponding population are needed, especially in low-HDI countries. Moreover, a standard molecular definition of ETEC infection is needed to be able to compare results across study sites.
Stories, Lives, and Basic Survival: A Refinement and Defense of the Narrative View
Authors: Schechtman Marya
Published: August 2007

Everyone loves a good story. But does everyone live a good story? It has frequently been asserted by philosophers, psychologists and others interested in understanding the distinctive nature of human existence that our lives do, or should, take a narrative form. Over the last few decades there has been a steady and growing focus on this narrative approach within philosophical discussions of personal identity, resulting in a wide range of narrative identity theories. While the narrative approach has shown great promise as a tool for addressing longstanding and intractable problems of personal identity, it has also given rise to much suspicion. Opponents of this approach charge it with overstating or distorting the structure of actual lives.
Self and Other: The Limits of Narrative Understanding
Authors: Zahavi Dan
Published: August 2007

If the self—as a popular view has it—is a narrative construction, if it arises out of discursive practices, it is reasonable to assume that the best possible avenue to self-understanding will be provided by those very narratives. If I want to know what it means to be a self, I should look closely at the stories that I and others tell about myself, since these stories constitute who I am. In the following I wish to question this train of thought. I will argue that we need to operate with a more primitive and fundamental notion of self; a notion of self that cannot be captured in terms of narrative structures. In a parallel move, I will argue that there is a crucial dimension of what it means to be other that is equally missed by the narrative approach. I will consequently defend the view that there are limits to the kind of understanding of self and others that narratives can provide.
Are the Dutch acquainted with and willing to try healthful food products? The role of food neophobia
Authors: Schickenberg B , van Assema P , Brug J , de Vries NK
Published: August 2007

Objectives

To assess participants’ acquaintance with and willingness to try healthful food alternatives, and to test the psychometric properties of an adapted Dutch version of the Food Neophobia Scale (FNS) in order to study the role of food neophobia in this context.

Design

A cross-sectional study incorporating two web-based questionnaires, including a retest of the FNS one week later. Measures included acquaintance with and willingness to try 15 healthful food alternatives, level of food neophobia, level of education, gender and age. Multiple linear regression analyses were used to study associations between demographics and level of food neophobia as well as associations between level of food neophobia and acquaintance with and willingness to try the healthful alternatives.

Setting

The study was conducted in The Netherlands using a representative Internet panel.

Participants

A total of 326 participants aged 18–50 years participated.

Results

Internal consistency and test–retest reliability of the FNS version used were sufficient. On average participants were acquainted with 7.9 of the products and modestly willing to try the products. Lowly educated participants had significantly higher FNS scores than highly educated participants (β = −0.23, P < 0.01). FNS score was significantly associated with acquaintance with (β = −0.21, P < 0.001) and willingness to try the healthful alternatives (β = −0.26, P < 0.001).

Conclusion

Further research into the role of food neophobia is warranted when wanting to stimulate the integration of healthful alternative products in the daily diet, especially among persons with low education.
Exotic amino acids across the K/T boundary – cometary origin and relevance for species extinction
Authors: Wallis Max K.
Published: August 2007

High levels of an exotic amino acid (Aib) and enhanced levels of iridium are evident in sediments pre-dating the Chicxulub impact by several tens of millennia. The source is thought to be debris from the break-up of a giant comet or trans-Neptunian body, a large fragment of which was the 10 km sized impactor that caused the famous iridium spike identified with the K/T boundary. In this paper it is argued that the Aib is not extra-terrestrial but the indicator of exotic pathogenic microfungi that flourished through this era. Its abundance implies a significant role for the fungi in the ecology, in species extinction and in driving evolution as the Tertiary period got underway. Microfungi containing the complex of genes that underlie the synthesis of Aib peptides flourished early on in the K/T transition and attacked species – including dinosaurs – that lacked counter immune mechanisms. Species (including mammals) that possessed or developed effective defence mechanisms won through in the early Tertiary-period flowering of new species. The genetic coding for Aib peptide synthesis might have evolved by natural selection. However, the coincidence in the boundary record between Aib peptides and the rise of iridium is indicative of the Aib blueprint arriving from space, in some carrier-organism or in microfungi themselves.
Calibration of the Pre-Main Sequence Binary System RS Cha: Impact of the Initial Chemical Mixture
Authors: Alecian E. , Lebreton Y. , Goupil M.-J. , Dupret M.-A. , Catala C.
Published: August 2007

Accurate observational data are available for the eclipsing double-lined spectroscopic binary system RS Cha, composed of two stars in the pre-main sequence stage of evolution: masses, radii, luminosities and effective temperatures of each component and metallicity of the system. This allows to build pre-main sequence stellar models representing the components of RS Cha and to constrain them in terms of physical ingredients, initial chemical composition and age.

We present stellar models we have calculated using the CESAM stellar evolution code for different sets of physical inputs (opacities, nuclear reaction rates, etc.) and different initial parameters (global metallicity, helium abundance, individual abundances of heavy elements). We discuss their ability to reproduce the observational constraints simultaneously for the two components. We focus on the impact on the models of the chemical mixture adopted and we propose a calibration for the RS Cha system providing an estimate of its age and initial helium abundance.
An Investigation of the Small Eccentricity in the Spectroscopic Binary System ζ TrA
Authors: Komonjinda S. , Hearnshaw J.B. , Ramm D.J.
Published: August 2007

The orbital eccentricity of the SB1 system ζ TrA (S.T. F9V, P ∼ 13 d) was found by Skuljan et al. (2004) to be e = 0.01398 ± 0.00019. Lucy (2005) devised a statistical test of the significance of this result, based on the amplitude and phase of the third harmonic in the Fourier analysis of the radial velocity data, and concluded that the non-zero eccentricity measured does not arise from a slightly eccentric Keplerian orbit, but from proximity effects in the binary. He therefore believes a circular orbit should be assigned to this system. In this paper we investigate one possible proximity effect, namely the tidal distortion of the primary star, such that the measured Doppler shift does not accurately indicate the centre of mass radial velocity of the star as a whole. The code of Wilson & Devinney (2003) was used to model the tidal distortion of the measured radial velocities, assuming a range of possible secondary masses, corresponding to M-dwarf companions. The result is that even for the lowest possible mass secondary of 0.09M⊙ with sin i = 1 (this gives the greatest tidal distortion, as it is closest to the primary) there is no significant effect on the radial velocities (the differences are of order 1 m s−1 as a result of the tidal effects). Similar negligible tidal effects arise using a white dwarf companion. We note that the difference between a circular orbit and the observations amounts to as much as 140 m s−1 at some phases, which is essentially the amplitude of the second harmonic in the data. Our conclusion is that this strong and highly significant second harmonic is most probably the result of a small orbital eccentricity as reported by Skuljan et al (2004). We note that the observed third harmonic according to Lucy (2005) has an amplitude of only 5.2 ± 2.0 m s−1, which is just over twice the error bar of its measurement, and that the predicted third harmonic for an eccentric orbit is only 1.6 m s−1.
Doppler Imaging of Stars with Roche–Geometry
Authors: Kővári Zs. , Bartus J. , Oláh K. , Strassmeier K.G. , Rice J.B. , Weber M. , Forgács-Dajka E.
Published: August 2007

Tests are carried out on retrieving Doppler maps from distorted stars in close binaries to estimate how Doppler imaging may be aliased by ellipticity. Maps obtained for the distorted shape are compared with the results of the simple spherical approximation, using real data of the RS CVn-type close binary star ζ Andromedae.
How to Measure Gravitational Aberration?
Authors: Křížek Michal , Šolcová Alena
Published: August 2007

In 1905, Henri Poincaré predicted the existence of gravitational waves and assumed their speed equal to the speed of light. If additionally the gravitational aberration would have the same magnitude as the aberration of light, we would observe several paradoxical phenomena. For instance, the orbit of two bodies would be unstable, since two attractive forces arise that are not in line and hence form a couple. This will be modelled by a nonautonomous system of ordinary differential equations with delay. In fact, any positive value of the gravitational aberration increases the angular momentum of such a system and this may contribute to the expansion of the universe. We found a remarkable coincidence between the Hubble constant and the increasing distance of the Moon from the Earth.

In 2000, Carlip showed that in general relativity gravitational aberration is almost cancelled out by velocity–dependent interactions. We show how the actual value of the gravitational aberration can be obtained by measurement of a single angle at a suitable time t* corresponding to the perihelion of an elliptic orbit. We also derive an a priori error estimate that expresses how accurately t* has to be determined to obtain the gravitational aberration to a prescribed tolerance.
U.S. Naval Observatory Double Star CD 2006.5
Authors: Mason Brian D. , Hartkopf William I.
Published: August 2007

The U.S. Naval Observatory has produced its second CDROM of double star catalogs. This successor to the 2001.0 CDROM includes the latest versions (June 30 2006) of four major double star catalogs maintained at the USNO:

•

Washington Double Star Catalog(WDS),

•

Second Photometric Magnitude Difference Catalog,

•

Fourth Catalog of Interferometric Measurements of Binary Stars, and

•

Sixth Catalog of Orbits of Visual Binary Stars.

Each of these catalogs had seen significant changes during the past six years; for example, the WDS has grown by over 150,000 measures and the number of systems in theInterferometric Cataloghas nearly doubled. Other improvements include precise coordinates for the vast majority of systems, as well as new observing lists for tens of thousands of “neglected” doubles.

Also included on this CDROM is aCatalog of Linear Elementsfor several hundred optical pairs. These elements should prove useful for improving the components' proper motions, as well as providing scale calibration out to several tens of arcseconds.

As was done with its predecessor, the new CDROM is automatically distributed free of charge to members of the double star community and to astronomy libraries. Others may receive a complementary copy upon request.
Multiplicity Study of Exoplanet Host Stars: the HD 3651 AB System
Authors: Mugrauer M. , Seifahrt A. , Neuhäuser R. , Mazeh T. , Schmidt T.
Published: August 2007

We report on new results of our multiplicity study and present our follow-up observations of the recently detected faint companion HD 3651 B, the first directly–imaged T dwarf companion of an exoplanet host star.
Eclipsing Binaries in Open Clusters
Authors: Southworth John
Published: August 2007

Detached eclipsing binaries are very useful objects for calibrating theoretical stellar models and checking their predictions. Detached eclipsing binaries in open clusters are particularly important because of the additional constraints on their age and chemical composition from their membership of the cluster. I compile a list containing absolute parameters of well-studied eclipsing binaries in open clusters, and present new observational data on the B-type systems V1481 Cyg and V2263 Cyg which are members of the young open cluster NGC 7128.
Application of the Field System-FS9 and a PC to the antenna control unit interface in radio astronomy in Peru
Authors: Vidal Erick , Ishitsuka José , Koyama Yasuhiro
Published: August 2007

We are in the process to transform a 32m antenna in Peru, used for telecommunications, into a Radio Telescope to perform Radio Astronomy in Peru. The 32m antenna of Peru constructed by NEC was used for telecommunications with communications satellites at 6 GHz for transmission, and 4 GHz for reception.

In collaboration of National Institute of Information and Communications Technology (NICT) Japan, and National Observatory of Japan we developed an Antenna Control System for the 32m antenna in Peru. It is based on the Field System FS9, software released by NASA for VLBI station, and an interface to link PC within FS9 software (PC-FS9) and Antenna Control Unit (ACU) of the 32 meters antenna.

The PC-FS9 controls the antenna, commands are translated by interface into control signals compatibles with the ACU using: an I/O digital card with two 20bits ports to read azimuth and elevation angles, one 16bits port for reading status of ACU, one 24bits port to send pulses to start or stop operations of antenna, two channels are analogue outputs to drive the azimuth and elevation motors of the antenna, a LCD display to show the status of interface and error messages, and one serial port for communications with PC-FS9.

The first experiment of the control system was made with 11m parabolic antenna of Kashima Space Research Center-NICT, where we tested the right working of the routines implemented for de FS9 software, and simulations was made with looped data between output and input of the interface, both test were done successfully.

With this scientific instrument we will be able to contribute with researching of astrophysics. We expect to into a near future to work at 6.7GHz to study Methanol masers, and higher frequencies with some improvements of the surface of the dish.
Building capacity for astronomy research and education in Africa
Authors: Martinez Peter
Published: August 2007

About 1.5% of the world's professional astronomers are based Africa, yet in terms of research output, African astronomers produce less than 1% of the world's astronomical research. The advent of new large-scale facilities such as SALT and HESS provides African astronomers with tools to pursue their research on the continent. Such facilities also provide unprecedented training opportunities for the next generation of African astronomers. This paper discusses recent efforts to develop astronomy education and research capacity on the continent. Various capacity-building initiatives are discussed, as well as the lessons learnt from those initiatives.
Suffa Radio Observatory in Uzbekistan: progress and radio-seeing research plans
Authors: Hojaev Alisher , Shanin G.I. , Artyomenko Yu.N.
Published: August 2007

The Suffa International Radio Observatory to be completed in coming years and the new radio astro-climate (seeing) research proposals for radio weather forecasting are described.
Modeling the electromagnetic ion cyclotron wave‐induced formation of detached subauroral proton arcs
Authors: Jordanova V. K. , Spasojevic M. , Thomsen M. F.
Published: August 2007

Detached dayside proton arcs have been recently observed at Earth with the IMAGE FUV instrument as subauroral arcs separated from the main oval and extending over several hours of local time in the afternoon sector. We investigate the mechanisms causing the proton precipitation during two subauroral arc events that occurred on 23 January 2001 and 18 June 2001. We employ our kinetic physics‐based model coupled with a dynamic plasmasphere model and calculate the growth rate of electromagnetic ion cyclotron (EMIC) waves self‐consistently with the evolving ring current H+, O+, and He+ ion distributions. Modeled plasmaspheric densities agree well with in situ observations from geosynchronous LANL satellites and duskside plasmapause observations from IMAGE EUV but overestimate the drainage plume extent toward noon on 18 June. Global images of precipitating H+ ions are obtained and compared with IMAGE observations of proton arcs. We find that EMIC waves are preferentially excited, and proton precipitation maximizes, within regions of spatial overlap of energetic ring current protons and dayside plasmaspheric plumes and along steep density gradients at the plasmapause. The model matches very well the temporal and spatial evolution of FUV observations on 23 January. The predicted location of the proton precipitation on 18 June extends a few hours westward of the observations, and an offset of 2 hours in the convection electric field is needed to reproduce well the evolution of the proton arc. This study indicates that cyclotron resonant wave‐particle interactions are a viable mechanism for the generation of subauroral proton arcs.
Lithospheric variations across the Superior Province, Ontario, Canada: Evidence from tomography and shear wave splitting
Authors: Frederiksen A. W. , Miong S.‐K. , Darbyshire F. A. , Eaton D. W. , Rondenay S. , Sol S.
Published: August 2007

The Superior Province of the Canadian Shield is the largest contiguous region of the Archean crust. A combination of data from multiple experiments is used to obtain shear wave splitting parameters and a three‐dimensional tomographic velocity model beneath a large portion of the Superior, corresponding approximately to the province of Ontario. Shear wave splits are obtained at 24 sites across the Superior, displaying strong (averaging 1.34 s) ENE‐WSW splitting at stations west of 86°W and weaker (0.67 s) E‐W splitting in the east. The fast direction is subparallel to both absolute plate motion and tectonic belt boundaries. The recovered tomographic velocity model shows a major boundary oriented NNW‐SSE, separating high velocities in the western Superior (WS) from low velocities in the east and coinciding with the divide between weak and strong shear wave splits. Other features include a 200‐km‐thick low‐velocity anomaly corresponding to the Nipigon Embayment, a 1.0‐Ga failed‐rift branch; and a linear low‐velocity anomaly in the east, attributed to the Great Meteor hot spot track. The Nipigon anomaly, in the western portion of the model, is probably in situ, while the Great Meteor track is displaced from crustal features associated with the hot spot. We interpret this displacement as evidence that the eastern lithosphere has been deformed by basal drag, while the western lithosphere has remained stable, and propose that the east‐west lithospheric boundary we have detected represents a change in mechanical properties, between stronger, higher velocity western material with consistent anisotropic fabric, and weaker eastern material with more variable fabric.
Comparison of northern and central Greenland ice core records of methanesulfonate covering the last glacial period
Authors: Jonsell Ulf , Hansson Margareta E. , Siggaard‐Andersen Marie‐Louise , Steffensen Jørgen‐Peder
Published: August 2007

Methanesulfonate (MS−) is measured in ice cores with the objective to obtain a proxy record of marine phytoplankton production of dimethylsulfide (DMS). We present a continuous MS− record covering the last glacial period from the North Greenland Ice Core Project (NGRIP) ice core and compare this record with the corresponding records previously presented from Greenland and, in particular, with the GISP2 ice core located 320 km south of NGRIP. Despite that the records have similar mean concentrations, their responses to climatic changes during the last glacial period are slightly different. NGRIP MS− concentrations were higher during the cold marine isotopic stages (MIS) 2 and 4 and lower during the warm MIS 5. This long‐term trend in MS−, which is similar to the inverse of the corresponding trend in δ18O, is not detected in the GISP2 MS− record. A systematic response in MS− concentrations to changes between Greenland stadials and interstadials is only detected in the GISP2 record. The different responses of the MS− signals to climate change during the last glacial period are possibly related to the partitioning of air masses reaching the two sites. In contrast to observations from Antarctic records, dust concentrations do not affect the MS− concentrations in the ice, whereas the deposition of sulfate probably is enhanced by high dust concentrations in the atmosphere. The MS− signal has a higher potential of being a proxy record of DMS production changes in Greenlandic compared to Antarctic ice cores.