bluuebunny/crossref_metadata_2025 huggingface dataset:
An Examination of Entry and Competitive Performance in Rural Banking Markets
Authors: Feinberg Robert M. , Reynolds Kara M.
Published: December 2010

This article explores the change in the level of competition in rural banking markets after the deregulation that occurred following passage of the Riegle‐Neal Act of 1994. Using an empirical model that utilizes both the number of banks and the value of deposits in a cross‐section of 278 rural markets, we decompose the impact of the entry of new banks into resulting changes in per capita demand and the costs/profits of local banks in 1994 and 2004. The results support the view that local banking markets have become more competitive since the mid‐1990s.
Asymmetric Enforcement of Cooperation in a Social Dilemma
Authors: Nikiforakis Nikos , Normann Hans-Theo , Wallace Brian
Published: December 2010

We use a public‐good experiment to analyze behavior in a decentralized asymmetric punishment institution. The institution is asymmetric in the sense that players differ in the effectiveness of their punishment. At the aggregate level, we observe remarkable similarities between outcomes in asymmetric and symmetric punishment institutions. Controlling for the average punishment effectiveness of the institutions, we find that asymmetric punishment institutions are as effective in fostering cooperation and are as efficient as symmetric institutions. At the individual level, we find that players with higher punishment effectiveness contribute similar amounts to the public account but have higher earnings and punish more than their weak counterparts.
Pass or Run: An Empirical Test of the Matching Pennies Game Using Data from the National Football League
Authors: McGarrity Joseph P. , Linnen Brian
Published: December 2010

This article examines play calling in the National Football League (NFL). It finds that a mixed strategy equilibrium game explains NFL play calling better than standard optimization techniques. When a quarterback is injured and replaced with a less capable backup, standard optimization theory suggests that the offense will run more often, passing less. Our game theoretic model predicts that the offense will not change its play calling because the defense will play against the run more often. Using every first half play from the 11 teams that had a starting quarterback miss action because of injury in the 2006 season, we find that the injury did not alter the likelihood that the offense would pass. We also find that coaches randomly mix passing and running plays, as the mixed strategy games predict.
Measuring Monetary Policy in a Small Open Economy with Managed Exchange Rates: The Case of Taiwan
Authors: Ho Tai-kuang , Yeh Kuo-chun
Published: December 2010

We use sign restrictions to identify monetary policy for a small open economy with heavily managed exchange rates. We apply the proposed sign restrictions to the Taiwanese case, where existing studies tend to find no clear effect of monetary policy shocks on the output and price level. Our principal findings are that a contractionary monetary policy shock causes a permanent and significant decline in real gross domestic product, broad money, and price level. Our identification scheme is able to avoid the puzzling impulse responses from which other identification schemes more or less suffer. The fact that monetary policy has not been correctly identified may have led existing studies to conclude that monetary policy is ineffective.
Are Financial Development and Trade Openness Complements or Substitutes?
Authors: Kim Dong-Hyeon , Lin Shu-Chin , Suen Yu-Bo
Published: December 2010

This article studies the long‐ and short‐run relationships between financial development and trade openness. Using the pooled mean group estimator of Pesaran, Shin, and Smith (1999) for unbalanced panel data for 87 countries over the 1960–2005 period, our empirical results indicate that long‐run complementarity between financial development and trade openness coexists with short‐run substitutionarity between the two policy variables. But when splitting the data into OECD and non‐OECD country groups, this finding can be observed only in non‐OECD countries. For OECD countries, financial development has negligible effects on trade. In addition, we find nonlinearity in the relationship in that long‐run responses of trade decrease with financial development. The article further finds coexistence of negative trade effects of financial fragility and positive trade impacts of financial depth.
The Deadliest of Games: The Institution of Dueling
Authors: Kingston Christopher G. , Wright Robert E.
Published: December 2010

Recent historical research indicates that ritualistic dueling had a rational basis. Basically, under certain social and economic conditions, individuals must fight in order to maintain their personal credit and social standing. We use a repeated two‐player sequential game with random matching to show how the institution of dueling could have functioned as a costly but incentive‐compatible means by which individuals could demonstrate their good faith dealings by defending their “honor.”
Market In efficiency in Person‐to‐Person Betting: Examining ‘Known Loser’ Insider Trading on the Exchanges
Authors: Marginson David
Published: December 2010

Applying the Shin z measure of market efficiency to the relatively new person‐to‐person internet betting exchanges, Smith, Paton, and Vaughan Williams found “significantly lower market biases” compared to bookmaker‐dominated markets. A reduced favorite‐longshot bias is interpreted as evidence that insider trading on the exchanges “is not widespread” and “not as commonplace … as is sometimes portrayed in the media.” Given that the Shin measure assumes “betting with bookies,” whereas the exchanges represent “betting without bookies,” the present study employs the notion of ‘significant mover’ to empirically test for the presence of ‘known loser’ insider trading on the exchanges where traditional notions of bookmaking do not apply. Findings indicate that, far from being less problematized by insider trading compared to racetrack betting, activity aimed at profiting from “known losers” may be potentially commonplace on the exchanges. This includes profiting from horses that are unplaced. This study offers new insight into the efficiency of betting markets.
An Experimental Investigation of Trust and Sequential Trade
Authors: Deck Cary A.
Published: December 2010

The trust game has been widely studied in the laboratory and is often presented as a model of exchange with incomplete contracting. The standard presentation of the game differs in three potentially important ways from the naturally occurring transactions it represents: buyer‐seller framing, payoff privacy, and price setting. Two sets of experiments look at the combined effect of these three features while varying the order of moves, an aspect of the problem that previous research has found significantly affects the likelihood of a successful trade. In both cases high levels of trust and low levels of trustworthiness are observed. Further experimental investigation suggests that the framing effect generates the increased trust but that payoff privacy reduces trustworthiness.
The Effect of a Program‐Based Housing Move on Employment: HOPE VI in Atlanta
Authors: Anil Bulent , Sjoquist David L. , Wallace Sally
Published: December 2010

We combine records of Atlanta Housing Authority (AHA) clients, Georgia Department of Labor (DOL) employment records, and neighborhood characteristics to analyze the causal effect of an exogenous move out of public housing on the employment of public housing residents. The exogenous move was caused by a HOPE VI or HOPE VI‐like project in Atlanta. We find that such an exogenous move has a positive and statistically significant effect on the probability of employment for those residents who moved relative to other public housing tenants. We also compare the change in employment of those whose exogenous move was to another public housing unit to those who took a housing voucher. We also compare the change in the probability of employment associated with an exogenous move and a voluntary move and find that both types of moves are associated with a greater probability of employment as compared to those who did not move.
Decentralized Taxation and the Size of Government: Evidence from Swiss State and Local Governments
Authors: Feld Lars P. , Kirchgässner Gebhard , Schaltegger Christoph A.
Published: December 2010

According to the Leviathan Model, fiscal federalism is a binding constraint on revenue‐maximizing government. The competitive pressure of fiscal federalism reduces public sector size, as compared to unitary states. This study uses panel data of Swiss cantons from 1980 to 1998 to empirically analyze the effect of different instruments on government revenue and its structure. Because of the considerable tax autonomy of sub‐national Swiss governments, it is possible to investigate different mechanisms by which fiscal federalism may influence government size. The results indicate that tax exporting has a revenue‐expanding effect; whereas, tax competition favors a smaller size of government. Fragmentation has no robust effect on the size of government revenue for Swiss cantons. The overall effect of revenue decentralization leads to fewer tax revenues but higher user charges. Thus, revenue decentralization favors a smaller size of government revenue and shifts government revenue from taxes to user charges.
Freedom and International Migration
Authors: Ashby Nathan J.
Published: December 2010

Economic and political freedoms are regressed on a bilateral cross section of international migrant stocks using ordinary least squares and Tobit techniques. A positive relationship between these variables is found. Economic freedom is statistically significant even when controlling for income per capita and political freedom. In addition, the impact of these freedoms on migration flows into OECD countries between 2001 and 2006 using fixed effects estimations is analyzed. The panel data analysis mostly corroborates the cross‐sectional analysis. The notable exception is that political freedom appears to have had a negative impact on migration flows during this period.
Testing Conflicting Political Economy Theories: Full‐Fledged versus Partial‐Scope Regional Trade Agreements
Authors: Liu Xuepeng
Published: December 2010

We apply a duration analysis to test the conflicting predictions of the median voter model and the lobbying model using panel data on regional trade agreement (RTA) formation. Our results show that the pro‐labor prediction of the median voter model is supported by the full‐fledged free trade areas and customs unions (FTAs/CUs), while the pro‐capital prediction of the lobbying model is supported by the partial‐scope preferential trade arrangements among developing countries. This finding holds better for the country pairs with more different capital‐labor ratios as a result of the stronger distributional effects of RTAs. The support for the median voter model (lobbying model) is stronger when the two countries in a pair have left‐oriented (right‐oriented) governments. I also find stronger support for the median voter model for the subset of FTAs/CUs with service coverage and stronger support for the lobbying model for countries that place higher weight on political contribution.
AN ASSESSMENT OF FOOD AND FIBER SYSTEMS KNOWLEDGE IN SELECTED OKLAHOMA HIGH SCHOOLS
Authors: Pense Seburn L. , Seburn L. James G.
Published: December 2010

In 1988, the National Research Council recognized agricultural literacy as a need for every K-12 student. After more than 13 years of agricultural literacy efforts, this criterion group ex-post facto study sought to assess the agricultural literacy of selected program completers (high school seniors) in Oklahoma. An instrument based on the Food and Fiber Systems Literacy (FFSL) Framework was developed to assess the agricultural literacy of students in grades 9-12. Six schools, two in each of three locations (urban, suburban, and rural) were selected for inclusion in the study. Comparisons were made between general education students and agricultural education students, between the three types of schools according to overall mean scores and between the five agricultural themes of the FFSL Framework. Agricultural education students and general education students did not differ in their overall mean agricultural knowledge scores. Students in rural schools, however, obtained lower overall mean agricultural knowledge scores than did students in urban and suburban schools, with rural schools scoring lowest in three of the five thematic areas of agriculture. Given the low agricultural knowledge scores of students overall, it was determined that the program completers who participated in the study were not agriculturally literate.
SOLUTIONS TO RECRUITMENT ISSUES OF HIGH SCHOOL AGRICULTURAL EDUCATION PROGRAMS
Authors: Myers Brian E. , Breja Lisa M. , Dyer James E.
Published: December 2010

Attracting and retaining quality students in agricultural education programs remains one of the most difficult problems faced by the profession. Much of the research that has been conducted addressing this problem has focused on the identification of obstacles to successful recruitment. This study focused on identifying solutions to those problems. Focus groups were organized in four states that had previously experienced enrollment declines, but have since rebounded. Eighteen issues were identified and solutions suggested to address each of those issues. Leading the list of issues were teacher quality and commitment, program quality, focus on production agriculture, perceived career opportunities, salary considerations, image of agriculture and the program, and availability of agriculture programs to students. Solutions focused on the preparation and hiring of quality teachers, adapting the curriculum to more accurately identify agriculture with science and technology, recruiting high quality students, providing meaningful activities and instruction, and promoting the agriculture program.
CHARACTERISTICS OF EFFECTIVE AGRICULTURE TEACHERS
Authors: Roberts T. Grady , Dyer James E.
Published: December 2010

The purpose of this Delphi study was to develop a consensus listing of those characteristics that comprise an effective agriculture teacher. Panel members consisted of agriculture teachers, county-level administrators, state FFA supervisory staff, and university faculty in agricultural education. The panel identified 40 characteristics of an effective agriculture teacher that were categorized into the areas of instruction, FFA, SAE, community relations, marketing, professionalism/professional growth, program planning/management, and personal qualities. Characteristics identified in the “personal qualities” category that are requisite for effective teachers warrant examination and possible remediation by current teacher education programs.
INQUIRY-BASED INSTRUCTION IN SECONDARY AGRICULTURAL EDUCATION: PROBLEM-SOLVING – AN OLD FRIEND REVISITED
Authors: Parr Brian , Edwards M. Craig
Published: December 2010

In the quest for more effective teaching and learning methods, one particular approach has surfaced as a “method of choice” for science educators: inquiry-based learning. A careful examination of this method suggests that it is very similar to the problem-based learning approach used by many agricultural educators. This study sought to synthesize research reported by earlier investigators—science educators and agricultural educators—who examined inquiry-based learning and who researched the problem-solving approach. It was also designed to examine similarities between the two approaches and to describe their level of “pedagogical congruence.” It was concluded that significant agreement exists between what some eminent scholars have said is the recommended pedagogy for improving student achievement and the teaching and learning exercised in many agricultural education classrooms. Future research should attempt to measure the science achievement of agricultural education students and teachers’ use of the problem-solving approach. If significant positive associations are established, then professional development and learning resources supporting use of the problem-solving approach should be developed and delivered. In addition, investigations should be carried out to better understand how agriculture teachers operationalize the problem-solving approach.
Mentoring First Year Agricultural Educators: Examining A State-Mandated Induction Program
Authors: Peiter Robin L. , Terry Jr. , Cartmell II D. Dwayne
Published: December 2010

This study determined perceptions of mentoring within a state-mandated first year teaching program of agriculture teachers and their assigned resident committee members. The objectives were: 1) Describe the personal characteristics of first year teachers and committee members, 2) Describe the mentor relationships that exist, 3) Compare perceptions of mentoring among committee members, and 4) Determine if participants approve its continuance. Results indicated that residency committee members believed they did provide mentoring to the first year teachers in agriculture. First year agriculture teachers perceived the mentor teacher to be the committee member who provided the most assistance during their first year of teaching. To the contrary, mentor teachers believed they did not assist with agricultural education issues or technical agriculture areas. Mentor teachers, administrators, higher education representatives, and first year agriculture teachers favored the continuance of this program; however, improvements could be made to strengthen the mentoring component. Recommendations included involving teacher educators as higher education representatives more and expand the residency committee to include an agriculture teacher as the mentor teacher. Special efforts to develop rapport beyond mandatory meetings and scheduled observations should be made. In addition, informal mentoring must continue to meet the first year agriculture teachers' needs.
Factors Influencing Career Choice Of Urban Agricultural Education Students
Authors: Esters Levon T. , Bowen Blannie E.
Published: December 2010

The purpose of the study was to identify factors influencing the career choice behaviors of students who graduated from an urban agricultural education program. A secondary purpose was to identify factors that discriminated between individuals who choose careers in agriculture and those who do not. Former students in the study indicated their parents and friends as the individuals most influencing their choice of a career. The events and experiences reported by former students who chose a career in agriculture focused around several themes which included career opportunities, high school educational experiences, and work experiences. Of the former students who did not choose a career in agriculture, events and experiences cited included having other career interests, a lack of interest in agriculture, and a lack of career opportunities. A discriminant analysis procedure was used to identify factors that discriminated between individuals who chose careers in agriculture and those who did not. Findings indicated that a discriminant model consisting of selected factors could not discriminate between former students who chose or did not choose a career in agriculture after they completed a secondary agricultural program.
Modeling Higher Order Thinking: The Alignment Between Objectives, Classroom Discourse, And Assessment
Authors: Ball Anna L. , Garton Bryan L.
Published: December 2010

The purpose of this study was to describe the levels of cognition modeled and the alignment among the levels of cognition modeled via course objectives, instructional strategies, and assessments in preservice teacher preparation courses. The accessible sample consisted of seven teacher educators teaching courses for secondary and middle school-level education majors at the University of Missouri-Columbia. Higher levels of cognition (application, analysis, synthesis, and evaluation) were modeled in 88% of the preservice teacher preparation course objectives. Lower levels of cognition, were modeled in 61% of classroom discourse. Application, analysis, synthesis, and evaluation levels of cognition, represented 39% of the classroom discourse. Higher levels of cognition as a whole represented a mean of 90% of all classroom assessments, with the synthesis level of cognition representing a mean of 40% of the classroom assessments for all instructors. Hierarchical cluster analysis methods were employed to examine the alignment among the cognitive levels of instructional objectives, classroom discourse, and assessments, respectively.
A Summary Of Distance Education In University Agricultural Education Departments
Authors: Roberts T. Grady , Dyer James E.
Published: December 2010

Distance education has become commonplace on many university campuses throughout the United States. Anecdotal evidence would suggest that distance education has also become commonplace in a few agricultural education departments. However, little is empirically known about the use of distance education within agricultural education departments. The purpose of this study was to obtain baseline data for distance education activities in agricultural education departments and programs at higher education institutions. A census of the department chairs or programs leaders was used to gather data using a bimodal data collection method. An 82% response rate was achieved. Results indicated that over two-thirds of the agricultural education departments offered distance education courses. Course management software was the technology used most to deliver courses, closely followed by the Internet. The most frequent academic level of distance education courses offered was graduate courses. The average department had just over three faculty members who taught distance education courses. From an administrative perspective, the biggest motivating factor for agricultural education faculty to teach distance education courses was to provide better service to their clientele. Also from an administrative perspective, the overwhelming barrier to distance education in agricultural education departments was time constraints of faculty members.
Contributions Of Agricultural Education, FFA, And 4-H to Student Leadership In Agricultural Colleges
Authors: Park Travis D. , Dyer James E.
Published: December 2010

University administrators have questioned the value of FFA and 4-H to agricultural colleges. Student leadership may be one unforeseen value of these organizations. FFA and 4-H have proclaimed to develop high levels of leadership in youth. To date, little research exists on the leadership outcomes of students who have participated in FFA and 4-H. Research presented in this paper identifies undergraduate student leaders in an agricultural college, delineates their prior leadership training and participation in high school activities, and proposes relationships between involvement in FFA and 4-H and undergraduate student leadership in a land-grant college of agriculture. The population studied in this research was undergraduate positional leaders (n=167) in the College of Agricultural and Life Sciences (CALS) at the University of Florida. Findings indicated that student leaders, one-third of which were former FFA members, were involved in a variety of high school leadership organizations. Student leaders across the college served in an average of 1.45 offices and participated in 2.36 organizations. Former FFA and 4-H members held more offices and participated in more organizations than non-FFA and non-4-H members.
Educational Opportunities For Agricultural Distance Programs
Authors: Swan Michael S. , Jackman Diane H. , Grubbs John
Published: December 2010

The study was guided by the following research objectives: (a) determine the demographics of agricultural Career and Technical Education (CTE) educators, (b) determine the demand for distance delivered educational alternatives among agricultural CTE educators, (c) determine the topic or subject areas most desired by agricultural CTE educators wanting distance delivered educational opportunities, (d) evaluate the influence of cost in the demand for distance delivered educational alternatives, and (e) determine the preferred method of distance delivery for additional education or training opportunities by agricultural CTE educators. The population for this study was agricultural CTE educators who were employed in Washington State public and private secondary schools attending the annual summer conference. The study included 249 of the 318 potential respondents. One-hundred ninety five usable surveys were completed for a response rate of 77.5 percent. Data were summarized by mean scores, frequencies, and percentages. The researchers concluded that agricultural CTE educators desired additional distance delivered education or training for personal and professional growth and that it should be available to them in their home area through the use of distance education. Distance education delivery methods to be utilized for this additional education and training were short courses, seminars, and conferences. The topic areas most desired were agriculture technology, plant and animal sciences, and educational technology. In addition, cost was determined to be an obstacle for agricultural CTE educators who desired additional education or training.
High-ozone layers in the middle and upper troposphere above Central Europe: potential import from the stratosphere along the subtropical jet stream
Authors: Trickl T. , Bärtsch-Ritter N. , Eisele H. , Furger M. , Mücke R. , Sprenger M. , Stohl A.
Published: December 2010

Abstract. Specific very dry high-ozone layers have been repeatedly observed in the middle and upper troposphere with the ozone lidar in Garmisch-Partenkirchen (Germany), starting roughly two days after the onset of high-pressure periods during the warm season. These episodes, previously not understood, were recently analysed based on extended simulations with the FLEXPART particle dispersion model and jet-stream analyses with the LAGRANTO transport model. The model results indicate import from the stratosphere along the subtropical jet stream over the Pacific Ocean and all the way back to the Atlantic Ocean, in some cases mixed with stratospheric air from intrusions over the North-West Pacific Ocean. Occasionally, also air from the boundary layers of East Asia and North America was admixed. The analysis suggests that stratospheric influence is the most important factor for the increase in ozone and is related to a rather shallow transfer of air from the stratosphere into the rapid upper-and mid-tropospheric air streams observed with the lidar. The in part considerable vertical and temporal extent of these layers and peak ozone mixing ratios between 80 and 150 \\unit{ppb} suggest this to be an important mechanism for stratosphere-to-troposphere transport.
Spatial and seasonal variability of heterotrophic and autotrophic soil respiration in a winter wheat stand
Authors: Prolingheuer N. , Scharnagl B. , Graf A. , Vereecken H. , Herbst M.
Published: December 2010

Abstract. Soil respiration (Rs), the sum of respiration by soil organisms (Rh) and roots (Ra), is known to be highly variable in both, space and time. There is less information available about the behaviour of Rh and Ra in time and particularly in space. The objective of this study was to quantify the contribution of each component to the temporal and spatial variability of soil respiration in a winter wheat stand. We measured soil respiration from March to July 2009 by closed-dynamic chambers for 61 sampling points in a 50×50 m plot in a winter wheat stand close to Jülich, Germany. Each sampling point was equipped with a 7 cm soil collar to measure total Rs and a 50 cm soil collar to exclude roots and to measure Rh only. Ra was assumed to equal Rs−Rh. Simultaneously, soil temperature and soil water content were measured in 6 cm depth. Biweekly the temporal development of the leaf area index was measured. On average, the heterotrophic contribution to Rs was 69% and thus higher than the autotrophic contribution. Seasonal changes of soil temperature and especially water content explained well the temporal variability of Rs (r2=0.74) and Ra (r2=0.80). Spatial variability of Ra was on average much higher (CV=88%) than the spatial variability of Rh (CV=30%). However, Rh was mainly randomly distributed in space, whereas Ra showed spatial autocorrelation. Spatial correlation and cross-variograms showed a significant spatial dependence of Rs on Ra. From our results we concluded that spatial variability of soil respiration in a winter wheat stand represented mainly the spatial variability of the autotrophic component.
Investigation of post-earthquake displacements in viaducts using Geodetic and Finite Element Methods
Authors: Güney D. , Acar M. , Özlüdemir M. T. , Çelik R. N.
Published: December 2010

Abstract. This paper presents the results of research into the post-earthquake displacements of the partially constructed road viaducts in Bolu, Turkey after the Izmit/Kocaeli, (Mw = 7.4), and Düzce (Mw = 7.1) earthquakes on 17 August and 12 November 1999, respectively. The investigations on the viaducts were carried out using both Geodetic and Finite Element Methods (FEM). Firstly, all the geodetic network stations selected for the project were checked because of the recent deformation in the area. Then, new control stations were placed between the piers of the viaducts. 28 object points were placed and measured on each pier to determine their displacements. In the second stage, the behaviours of the viaducts were modelled using the FEM, and the Düzce earthquake acceleration record was analysed to observe the response of the viaducts in a time history domain. The modelled displacement response of the viaducts was compared with the geodetic measurements in order to interpret the sensitivity of the design calculation of the engineering model. The pier displacements that were geodetically measured and calculated using FEM peak pier displacements showed an increase in the piers located closer to the surface rupture from the Izmit/Kocaeli and Düzce earthquakes. The agreement between the observed and modelled displacements decreases with the increase in the distance from the fault line. Since, near the fault trace the horizontal displacement field is discontinuous and large inelastic deformation is expected, the behaviour of the part of the structure located near the fault line cannot be easily reproduced by FEM simulations. This is because the applied model loads derived from the source acceleration spectra cannot be included in the localized finite deformation effects. In order to obtain an improved engineering analysis, it is necessary to utilise more parameters in the numerical analysis.
A comparative study on chaoticity of equatorial/low latitude ionosphere over Indian subcontinent during geomagnetically quiet and disturbed periods
Authors: Unnikrishnan K.
Published: December 2010

Abstract. In the present study, the latitudinal aspect of chaotic behaviour of ionosphere during quiet and storm periods are analyzed and compared by using GPS TEC time series measured at equatorial trough, crest and outside crest stations over Indian subcontinent, by employing the chaotic quantifiers like Lyapunov exponent (LE), correlation dimension (CD), entropy and nonlinear prediction error (NPE). It is observed that the values of LE are low for storm periods compared to those of quiet periods for all the stations considered here. The lowest value of LE is observed at the trough station, Agatti (2.38° N, Geomagnetically), and highest at crest station, Mumbai (10.09° N, Geomagnetically) for both quiet and storm periods. The values of correlation dimension computed for TEC time series are in the range 2.23–2.74 for quiet period, which indicate that equatorial ionosphere may be described with three variables during quiet period. But the crest station Mumbai shows a higher value of CD (3.373) during storm time, which asserts that four variables are necessary to describe the system during storm period. The values of non linear prediction error (NPE) are lower for Agatti (2.38° N, Geomagnetically) and Jodhpur (18.3° N, Geomagnetically), during storm period, compared to those of quiet period, mainly because of the predominance of non linear aspects during storm periods The surrogate data test is carried out and on the basis of the significance of difference of the original data and surrogates for various aspects, the surrogate data test rejects the null hypothesis that the time series of TEC during storm and quiet times represent a linear stochastic process. It is also observed that using state space model, detrended TEC can be predicted, which reasonably reproduces the observed data. Based on the values of the above quantifiers, the features of chaotic behaviour of equatorial trough crest and outside the crest regions of ionosphere during geomagnetically quiet and disturbed periods are briefly discussed.
Stand-alone single-frequency GPS ice velocity observations on Nordenskiöldbreen, Svalbard
Authors: den Ouden M. A. G. , Reijmer C. H. , Pohjola V. , van de Wal R. S. W. , Oerlemans J. , Boot W.
Published: December 2010

Abstract. Precise measurements of ice-flow velocities are necessary for a proper understanding of the dynamics of glaciers and their response to climate change. We use stand-alone single-frequency GPS receivers for this purpose. They are designed to operate unattended for 1–3 years, allowing uninterrupted measurements for long periods with hourly temporal resolution. We present the system and illustrate its functioning using data from 9 GPS receivers deployed on Nordenskiöldbreen, Svalbard, for the period 2006–2009. The accuracy of the receivers is 1.62 m based on the standard deviation in the average location of a stationary reference station (NBRef). Both the location of NBRef and the observed flow velocities agree within one standard deviation with DGPS measurements. Periodicity (6, 8, 12, 24 h) in the NBRef data is largely explained by the atmospheric, mainly ionospheric, influence on the GPS signal. A (weighed) running-average on the observed locations significantly reduces the standard deviation and removes high frequency periodicities, but also reduces the temporal resolution. Results show annual average velocities varying between 40 and 55 m yr−1 at stations on the central flow-line. On weekly to monthly time-scales we observe a peak in the flow velocities (from 60 to 90 m yr−1) at the beginning of July related to increased melt-rates. No significant lag is observed between the timing of the maximum speed between different stations. This is likely due to the limited temporal resolution after averaging in combination with the relatively small distance (max. ±13 km) between the stations.
Carcinomas of Distal Fallopian Tube and Their Association with Tubal Intraepithelial Carcinoma: Do They Share a Common “Precursor” Lesion? Loss of Heterozygosity and Immunohistochemical Analysis Using PAX 2, WT-1, and P53 Markers
Authors: Chivukula Mamatha , Niemeier Leo A. , Edwards Robert , Nikiforova Marina , Mantha Geetha , McManus Kim , Carter Gloria
Published: December 2010

As the role of distal fallopian tube as organ of serous carcinogenesis is emerging, additional literature on the role of tubal intraepithelial carcinoma (TIC) as a precursor lesion in a subset of primary peritoneal serous carcinomas (PPSC is emerging as well. TIC although fallopian tube in origin can be genetically related to ovarian/peritoneal carcinomas. The role of PAX2 in primary fallopian tube carcinomas (PFTC)/PPSC is yet to be defined. The aim of our study was to understand if the biologic properties of tumors arising in the distal fallopian tube that remain as PFTC are different when they seed on to the peritoneal surface (PPSC). A panel of 6 polymorphic microsatellite markers corresponding to p53, PAX2, and WT1 tumor suppressor genes were studied. Invasive carcinomas as well as TIC arising in the distal fallopian tube when remain as PFTC appears to exhibit different LOH patterns in comparison to PPSC. PAX 2 LOH patterns might represent a “hidden PAX 2 signature” analogous to p53 signatures. PAX 2 might be an emerging marker for detection of early serous carcinomas particularly in BRCA + women.
The Nucleobase‐Cation‐Symport‐1 Family of Membrane Transport Proteins
Authors: Weyand Simone , Ma Pikyee , Saidijam Massoud , Baldwin Jocelyn , Beckstein Oliver , Jackson Scott , Suzuki Shun'ichi , Patching Simon G , Shimamura Tatsuro , Sansom Mark SP , Iwata So , Cameron Alexander D , Baldwin Stephen A , Henderson Peter JF
Published: December 2010

The evolutionary relationships of membrane transport proteins of the nucleobase‐cation‐symport (NCS‐1) family from bacteria, fungi, and plants are described. The reported substrates of the NCS‐1 family include nucleobases, hydantoins, and vitamins. Secondary active transport of substrate accompanied by a sodium ion, or possibly a proton, is the usual mechanism of energization. A strategy for the amplified expression, purification, and activity assays of bacterial members of the NCS‐1 family is described. Conditions are given for the production of diffracting crystals of one member, the Na+‐coupled transporter for aromatic hydantoins, ‘Mhp1’, fromMicrobacterium liquefaciens. The 3D structures of three forms of the Mhp1 protein are discussed in terms of one open‐outward, one substrate‐occluded, and one open‐inward conformation contributing to a molecular dynamics simulation of the alternating‐access model of membrane transport. The unexpected similarity of the protein fold of Mhp1 to those of transport proteins, hitherto thought to be from different evolutionary families, is discussed.
Peptidyl‐α‐Hydroxyglycine α‐Amidating Lyase (PAL)
Authors: Chufán Eduardo E , Eipper Betty , Mains Richard , Amzel Mario L
Published: December 2010

Many peptide hormones and neuropeptides require an amidated carboxy terminal for full biological activity. This reaction is carried out in two steps: hydroxylation of a C‐terminal glycine and cleavage of the C N bond with the release of glyoxylate. The enzyme peptidyl‐α‐hydroxyglycine α‐amidating lyase (PAL; EC 4.3.2.5) catalyzes the second step of this reaction,N‐dealkylation of the peptidyl‐α‐hydroxyglycine to generate the α‐amidated peptide and glyoxylate. The X‐ray crystal structure of the PAL catalytic core (PALcc), alone and in complex with the nonpeptidic substrate α‐hydroxyhippuric acid, shows that PAL folds as a six‐bladed β‐propeller. The active site is formed by a Zn2+ion coordinated by three histidine residues; the substrate binds to this site with its α‐hydroxyl group coordinated to the Zn2+ion. A tyrosine residue (Tyr654) at the active site acts as the catalytic base for hydroxyl deprotonation, an unusual role for tyrosine residue. In the reaction mechanism, proposed on the basis of the structure and validated by biochemical analysis of site‐directed PALcc mutants, the substrate α‐hydroxyl that coordinates the catalytic Zn2+directly is deprotonated by Tyr654. The generation of the required tyrosinate is aided by an arginine residue that, together with the Zn2+, lowers the pKaof the catalytic tyrosine.
Mo–Se‐Containing Nicotinate Dehydrogenase
Authors: Dobbek Holger , Pierik Antonio J
Published: December 2010

Se Mo‐containing nicotinate dehydrogenase (NDH) of the anaerobic soil bacteriumEubacterium barkericatalyzes the hydroxylation of nicotinate with water and NADP+to 6‐hydroxynicotinate, one proton, and NADPH. This reaction is the first step in the degradation of nicotinate to pyruvate and propionate in a unique fermentation pathway. NDH is constituted by four different subunits and contains a Mo‐bound pyranopterin cofactor linked to cytosine dinucleotide, two different [2Fe2S] centers, and flavin adenine dinucleotide to facilitate the transfer of a hydride ion on NADP+. NDH is a member of the family of molybdenum hydroxylases and shares several distinctive features with other members of this enzyme family, such as xanthine oxidoreductase, aldehyde oxidase, and the Mo‐containing carbon monoxide dehydrogenase. The reactivity of NDH critically depends on the presence of selenium in the active site, where it is bound as a labile nonselenocysteinyl selenium ligand to molybdenum. The role of the selenium ligand is likely to accelerate the formal hydride transfer from the substrate into the Mo Se bond, displaying a novel reactivity of selenium in nature.
d
‐ and
f
‐
B
lock Transition Metal Complexes with Bulky Allyl Ligands
Authors: Chmely Stephen C. , Hanusa Timothy P.
Published: December 2010

The allyl anion (C
3
H
5
−
) is often found in combination with other ligands in organometallic complexes. Its compact size, however, means that compounds in which it is the only or principal type of ligand are frequently coordinatively unsaturated and prone to decomposition. Sterically bulky substituents (e.g.,—SiMe
3
) placed on the allyl group will increase its effective size, often enhancing the thermal, and in some cases oxidative, stability of the associated metal complexes. Compounds of the d‐ and f‐block metals containing bulky allyl ligands display a wide range of monomeric, oligomeric, and polymeric structures. Some of these complexes have no counterparts with unsubstituted allyls, and others are active polymerization catalysts. Research in this area has markedly expanded the range of metals, structural types, and associated reactions that can be incorporated into metal–allyl chemistry.
Medicinal Inorganic Chemistry: Correcting Essential Metal‐Ion Deficiencies
Authors: Thompson Katherine H.
Published: December 2010

Essential metal ions are those for which there is a known requirement for good health in the body. When dietary intake does not, or cannot, maintain adequate tissue stores of an essential trace or ultratrace metal ion, metal‐ion supplementation may be necessary. Simple salts of metal ions are often poorly tolerated, not well absorbed, or too rapidly excreted (or all three of these); therefore, appropriate ligand binding of the particular metal ion can significantly improve the success of supplementation efforts. The most common deficiency disorder, iron‐deficiency anemia, is now treated with a number of iron complexes, e.g., Ferrochel™ and ferrous gluconate, that are superior to simple iron salts such as ferrous sulfate; others, such as ferric maltol, are being proposed as useful substitutes. Marginal deficiencies of trace and ultratrace elements, such as zinc, copper, manganese, and chromium, are purported to have long‐term negative health effects, especially in aging or ill populations. Defining marginal deficiency is difficult, owing to lack of reliable and accurate biomarkers for the determination of trace element status.
Optical Tweezers
Authors: Greulich Karl Otto
Published: December 2010

Infrared lasers focused with high numerical aperture into a microscope are used to exert and measure forces in the piconewton range. Simple light pressure and the more complex ‘gradient forces’ are exploited. Unlike any other micromanipulation tool, optical tweezers can, for example, be used to work in the interior of unopened living cells to support cell fusion, to stimulate specificity in the interaction of immune cells and to simulate heart infarction. Here, a variant of optical tweezers, erythrocyte‐mediated force application is particularly helpful. Other applications are in humanin vitrofertilisation, where hundreds of children owe their existence to optical tweezers, and blood pressure studies. Studies on infection of a single cell by a virus or bacterium and on the organisation, of one of the fundamental processes of life – the generation of motion (by the centrosome) – complement the wide field of applications of optical tweezers in the life sciences.

Key Concepts:

Light is focused with very high aperture into a microscope so that light pressure and gradient forces can be used to hold, manipulate and measure forces of microscopic objects.

Optical tweezers can be added to most standard microscopes with only little effort.

Infrared light is used, which has a large penetration depth in biological tissue. Thus, one can work in the interior of unopened objects.

With red blood cells as handle, forces of optical tweezers can be fully exploited (erythrocyte‐mediated force application, EMFA).

Optical tweezers can be used to establish contact between microsopic objects as well as to move particles and organelles in the interior of closed objects.

The force transduction is gentle and thus also suitable for fragile targets.
tRNABiogenesis
Authors: Jackman Jane E
Published: December 2010

During transferribonucleic acid(tRNA) biogenesis, tRNA molecules undergo extensive processing before they can fulfill their essential role as the adapter molecule in translation, bringing amino acids into the ribosome for protein synthesis. Many components of the tRNA processing machinery have been identified in a variety of organisms, and a comparison of these shows many common features. However, species‐specific features have also been identified, and these present interesting examples of alternative evolutionary pathways and suggest additional interactions between tRNA processing machinery and other cellular processes. An increasing number of mechanisms have been identified that serve to safeguard the tRNA population, either by repair or removal of damaged tRNA species. A picture emerges of a tightly controlled and complex process required for tRNA biogenesis.

Key Concepts:

tRNA molecules are heavily processed before their use in translation.

Many aspects of tRNA splicing are conserved in multiple domains of life, but there are significant species‐specific differences.

tRNA modification enzymes exhibit different mechanisms for recognition of specific tRNA species to be modified.

Multiple quality control pathways exist that serve to repair and protect the cellular tRNA pool.
Ultrashort Laser‐Pulse Medical Imaging
Authors: Ben‐David Moshe , Cohen Reut , Harbater Osnat , Steinberg Idan , Tepper Michal , Gannot Israel
Published: December 2010

Short‐pulse tunable lasers are powerful tools that enable us to measure photon time of flight, lifetime changes, trigger processes, and operation in a nonionizing spectral range. Monochromatic X‐ray radiation can also be achieved with the use of a free‐electron laser (FEL). In this case, the amount of hazardous radiation is significantly lowered; however, the resolution is much higher. Therefore, FELs can serve as important tool for various imaging methods in vitro or in vivo. This article covers a few optical imaging methods such as optical tomography, optical coherence tomography (OCT), fluorescence lifetime imaging, FEL X‐ray tomography for in vivo imaging, and coherent anti‐Stokes Raman spectroscopy (CARS) for accurate chemical structures detection in live cells in vitro. All these imaging and spectral methods became possible only because of these lasers.
Nuclear Magnetic Resonance and Statistical Analysis
Authors: Ye Tao , Zhang Shucha , Gowda G. A. Nagana , Raftery Daniel
Published: December 2010

The impressive high resolution of nuclear magnetic resonance (NMR), its large dynamic range, and especially robust reproducibility lend themselves to advanced statistical methods that can be harnessed to analyze a large variety of complex samples. The primary example of this approach is in the rapidly expanding field of metabolomics that is focused on better understanding systems biology and for the identification of biomarkers of various biological states. In metabolomics, a large number of small‐molecule metabolites from body fluids or tissues are detected quantitatively in a single step, and then analyzed with multivariate statistical methods to yield information that is essential for systems biology, drug discovery, early disease diagnosis, toxicology, food and nutrition sciences, and other studies. NMR‐based metabolomic studies have been very successful due to the high quality and reliability of the methodology. In this article, we summarize the major experimental and statistical methods used in combining NMR and advanced statistical analyses especially in metabolomics along with a description of some important applications.