Showing papers by "Tallinn University of Technology published in 2005"

Characterization of Phenolic Profiles of Northern European Berries by Capillary Electrophoresis and Determination of their Antioxidant Activity

Abstract: Berries are known to contain phenolic substances (i.e., flavonoids and phenolic acids), which comprise two large and heterogeneous groups of biologically active nonnutrients. This investigation evaluated the content and profile of the phenolic compounds present in six different berries found in Northern Europe. The latter included bilberry (Vaccinium myrtillus), cowberry (Vaccinium vitis-idaea), cranberry (Vaccinium oxycoccus), strawberry (Fragaria ananassa), black currant (Ribes nigrum), and red currant (Ribes rubrum). The study was focused on two areas. The first involved the extraction and analysis of berries for total phenolic content and determination of their antioxidant activity. The total phenolic level of berries was correlated with their antioxidant activity. Second, the berry extracts were analyzed by capillary electrophoresis to determine the content and profile of selected bioactive compounds. The analytes of interest included trans-resveratrol, cinnamic acid, ferulic acid, p-coumaric acid, q...

An international comparative study of work-family stress and occupational strain

Abstract: Contents: J.N. Cleveland, E.A. Fleishman, Series Foreword. V.E. Schein, Foreword. S. Poelmans, Editorial Introduction. Part I:Individual-International Perspective. S. Poelmans, M. O'Driscoll, B. Beham, An Overview of International Research on the Work-Family Interface. E.E. Kossek, D. Meece, M.E. Barratt, B.E. Prince, U.S. Latino Migrant Farm Workers: Managing Acculturative Stress and Conserving Work-Family Resources. P.E. Spector, T.D. Allen, S. Poelmans, C.L. Cooper, P. Bernin, P. Hart, L. Lu, K. Miller, L.R. de Moraes, G.M. Ostrognay, H. Pitariu, V. Salamatov, J. Salgado, J.I. Sanchez, O.L. Siu, M. Teichmann, T. Theorell, P. Vlerick, M. Widerszal-Bazyl, S. Yu, An International Comparative Study of Work-Family Stress and Occupational Strain. Part II:Organizational-International Perspective. U. Kinnunen, S. Mauno, S. Geurts, J. Dikkers, Work-Family Culture in Organizations: Theoretical and Empirical Approaches. P. Caligiuri, M. Lazarova, Work-Life Balance and the Effective Management of Global Assignees. J.S.E. Dikkers, L. den Dulk, S.A.E. Geurts, B. Peper, Work-Nonwork Culture, Utilization of Work-Nonwork Arrangements, and Employee-Related Outcomes in Two Dutch Organizations. W.R. Poster, Organizational Change, Globalization, and Work-Family Programs: Case Studies From India and the United States. L. den Dulk, Workplace Work-Family Arrangements: A Study and Explanatory Framework of Differences Between Organizational Provisions in Different Welfare States. Part III:Cross-Cultural Perspective. M. Westman, Cross-Cultural Differences in Crossover Research. S. Aryee, The Work-Family Interface in Urban Sub-Saharan Africa: A Theoretical Analysis. N. Yang, Individualism--Collectivism and Work-Family Interfaces: A Sino-U.S. Comparison. M.A. Shaffer, J.R.W. Joplin, A.M. Francesco, T. Lau, Easing the Pain: A Cross-Cultural Study of Support Resources and Their Influence on Work-Family Conflict. Part IV:Case Studies. N. Chinchilla, S. Poelmans, Case Study 1: Emigration to Mexico: Promotion and the Dual-Career Couple. B. Beham, S. Poelmans, Instructor's Manual for Case Study 1. S. Poelmans, W. de Waal-Andrews, Case Study 2: Launching Flexible Work Arrangements within Procter & Gamble EMEA. B. Beham, S. Poelmans, Instructor's Manual for Case Study 2. Part V:Conclusions and Recommendations for Future Research. R.S. Bhagat, B.C. Krishnan, Methodological Issues in Work-Family Research in an Era of Globalization. M.J. Gelfand, A.P. Knight, Cross-Cultural Perspectives on Work-Family Conflict. J.M. Bowes, Emphasizing the Family in Work-Family Research: A Review of Current Research and Recommendations for Future Directions. S. Poelmans, Organizational Research on Work and Family: Recommendations for Future Research. R. Rapoport, S. Lewis, L. Bailyn, R. Gambles, Epilogue: Globalization and the Integration of Work With Personal Life.

The Arabidopsis ROCK-N-ROLLERS gene encodes a homolog of the yeast ATP-dependent DNA helicase MER3 and is required for normal meiotic crossover formation.

Abstract: Recent studies in Saccharomyces cerevisiae have unveiled that meiotic recombination crossovers are formed by two genetically distinct pathways: a major interference-sensitive pathway and a minor interference-insensitive pathway. Several proteins, including the MSH4/MSH5 heterodimer and the MER3 DNA helicase, are indispensable for the interference-sensitive pathway. MSH4 homologs have been identified in mice and Arabidopsis and shown to be required for normal levels of crossovers, suggesting that the function of MSH4 may be conserved among major eukaryotic kingdoms. However, it is not known whether an MER3-like function is also required for meiosis in animals and plants. We have identified an Arabidopsis gene that encodes a putative MER3 homolog and is preferentially expressed in meiocytes. T-DNA insertional mutants of this gene exhibit defects in fertility and meiosis. Detailed cytological studies indicate that the mutants are defective in homolog synapsis and crossover formation, resulting in a reduction of bivalents and in the formation of univalents at late prophase I. We have named this gene ROCK-N-ROLLERS (RCK) to reflect the mutant phenotype of chromosomes undergoing the meiotic 'dance' either in pairs or individually. Our results demonstrate that an MER3-like function is required for meiotic crossover in plants and provide further support for the idea that Arabidopsis, like the budding yeast, possesses both interference-sensitive and insensitive pathways for crossover formation.

The AtRAD51C Gene Is Required for Normal Meiotic Chromosome Synapsis and Double-Stranded Break Repair in Arabidopsis

Abstract: Meiotic prophase I is a complex process involving homologous chromosome (homolog) pairing, synapsis, and recombination. The budding yeast (Saccharomyces cerevisiae) RAD51 gene is known to be important for recombination and DNA repair in the mitotic cell cycle. In addition, RAD51 is required for meiosis and its Arabidopsis (Arabidopsis thaliana) ortholog is important for normal meiotic homolog pairing, synapsis, and repair of double-stranded breaks. In vertebrate cell cultures, the RAD51 paralog RAD51C is also important for mitotic homologous recombination and maintenance of genome integrity. However, the function of RAD51C in meiosis is not well understood. Here we describe the identification and analysis of a mutation in the Arabidopsis RAD51C ortholog, AtRAD51C. Although the atrad51c-1 mutant has normal vegetative and flower development and has no detectable abnormality in mitosis, it is completely male and female sterile. During early meiosis, homologous chromosomes in atrad51c-1 fail to undergo synapsis and become severely fragmented. In addition, analysis of the atrad51c-1 atspo11-1 double mutant showed that fragmentation was nearly completely suppressed by the atspo11-1 mutation, indicating that the fragmentation largely represents a defect in processing double-stranded breaks generated by AtSPO11-1. Fluorescence in situ hybridization experiments suggest that homolog juxtaposition might also be abnormal in atrad51c-1 meiocytes. These results demonstrate that AtRAD51C is essential for normal meiosis and is probably required for homologous synapsis.

Reforms and Economic Growth in Transition Economies: Complementarity, Sequencing and Speed

Abstract: This paper considers the effects of sequencing and reform speed on output performance in transition countries. These largely unsettled issues are addressed using principal component techniques to construct reform clusters and by explicit tests of speed effects. The results indicate that broad-based reforms are good for output growth, but so is a policy of liberalisation and small-scale privatisation without structural reforms. Conversely, large-scale privatisation without adjoining reforms, market opening without supporting reforms and bank liberalisation without enterprise restructuring affect growth negatively. Swift reform policies allow transition countries to benefit from higher growth for longer time. The speed of reforms appears otherwise to have little effect on growth in the short and medium term.

Fast ferry traffic as a qualitatively new forcing factor of environmental processes in non-tidal sea areas : A case study in Tallinn Bay, Baltic Sea

Abstract: The impact of wake wash from high-speed ferries on the coastal environment in non-tidal seas is analysed in terms of wave energy and power, and properties of the largest waves. Shown is that hydrodynamic loads caused by heavy high-speed traffic may play a decisive role not only in low-energy coasts but also in certain areas with high wind wave activity. For example, ship-generated waves form, at least, about 5–8% from the total wave energy and about 18–35% from the wave power in the coastal areas of Tallinn Bay exposed to dominating winds. The periods of wake waves from high-speed ships frequently are much larger than dominating periods of wind waves. The leading waves typically have a height of about 1 m and a period of 10–15 s. Such waves extremely seldom occur in natural conditions in many regions of semi-enclosed seas. They cause unusually high hydrodynamic loads in the deeper part of the nearshore. The fast ferry traffic thus is a qualitatively new forcing component of vital impact on the local ecosystem. It is demonstrated that wakes from high-speed ferries may trigger considerable changes of the existing balance of coastal processes. Owing to their low decay rates combined with their exceptional compactness after crossing many kilometres of the sea surface, such wakes may cause considerable remote impact of the ship traffic. This feature has to be addressed in the analysis of the impact of harbours and associated ship traffic in the neighbourhood of vulnerable areas.

Drifting Together or Falling Apart? The Empirics of Regional Economic Growth in Post-Unification Germany

Abstract: The objective of this paper is to address the question of convergence across German districts in the first decade after German unification by drawing out and emphasising some stylised facts of regional per capita income dynamics. We achieve this by employing non-parametric techniques which focus on the evolution of the entire cross-sectional income distribution. In particular, we follow a distributional approach to convergence based on kernel density estimation and implement a number of tests to establish the statistical significance of our findings. This paper finds that the relative income distribution appears to be stratifying into a trimodal/bimodal distribution.

Scrub nurse robot system-intraoperative motion analysis of a scrub nurse and timed-automata-based model for surgery

Abstract: The goal of the project described in this paper is to develop a human-adaptive Scrub Nurse Robot (SNR) that can adapt to surgeons with various levels of skill and experience in order to compensate for the present severe shortage of scrub nurses. To determine the specifications of the SNR, we analyzed real intraoperative behavior of a scrub nurse, and then modeled the entire surgical procedure with key participants by a multilevel modeling approach using the extended timed-automata-based formalism of Uppaal. Specifically, first, we videotaped the intraoperative motions of a scrub nurse and a surgeon in a thoracoscopic surgery performed on an infant pig, and analyzed their motions during the skin incision. Second, the motions of the nurse's right wrist, elbow, and shoulder were modeled with the timed automata. Third, the entire surgical procedure as well as actions and statuses of key participants was also modeled. Finally, it is shown that the proposed multilevel modeling approach also facilitates the model checking that is considered efficient in the SNR motion analysis and its adaptive motion planning.

Integrated palaeoecological and historical data in the service of fine-resolution land use and ecological change assessment during the last 1000 years in Rõuge, southern Estonia

Abstract: Aims Our aim is to reconstruct decadal scale development of historical landscapes during the last 1000 years by means of fossil pollen analysis of annually laminated lake sediments, and detailed historical maps and documents. Location Lake Rouge Tougjarv (Estonia), a small lake with annually laminated lake sediments situated in a dense prehistoric setting. Methods The chronology of the palaeodata is based on the annual laminations supported by AMS 14C and 210Pb dating and 137Cs, 241Am, and spheroidal carbonaceous particle marker horizons. The time-scale and resolution allows fine sampling (the pollen samples generally comprise 3.5 years) and vegetation change reconstruction. Relevant source area of pollen (RSAP) of the lake was estimated, and the statistical zonation, rate of change, palynological richness, and DCA and PCA ordinations were generated on the basis of the pollen data. The historical calibration data set (maps, numerical information on population, domestic stock, farmland division, etc.) is based on archival material preserved in the Estonian Historical Archives. Results The topmost part (0–180 cm) of the sediment column of Lake Rouge Tougjarv, covering the last 1000 years, is visibly laminated carbonaceous gyttja. The varve chronology extends from ad 2000 to ad 1339, with a cumulative ± 9-year error estimate. Beyond this the chronology is extrapolated using the 14C date and varve age–depth estimations. The simulation of the RSAP of Lake Tougjarv shows that the major portion of the pollen loading originating from local vegetation is derived from plants growing within 2000 m of the sampling site. The pollen record divides into five statistically significant subgroups, which fall on the PCA plot into three clusters reflecting the general openness–closedness of the landscape. During the period between ad 1000 and 1200 (RT 1) the Rouge area was generally wooded with birch, spruce and pine forests. The advancement of extensive farming gradually opened up the landscape between ad 1200 and 1650 (RT 2 and RT 3). The maximum openness of the landscape was reached between ad 1650 and 1875 (RT 4), with the most open period in the late eighteenth century. Historical maps from 1684 and 1870–99 and available quantitative data on population, domestic stock, farmland division, etc. show the same trend. The pollen data covering the last 125 years, and maps from 1935 and 1995, show the reduction of arable land in RSAP of the lake under investigation and the reduction of open land to an extent comparable with the end of the seventeenth century. Main conclusions The formation and development of the cultural landscape at Rouge over the last 1000 years is characterized by rapid changes in floristic richness and rates of vegetation change attributed to certain historic processes in the RSAP. Five phases of landscape and social development are clearly distinguished during the last 1000 years. The decadal scale vegetation response to human-induced forcing agrees with historical maps and documents and could be used for past landscapes prior to the period with solid historical data.

The Arabidopsis thaliana PARTING DANCERS Gene Encoding a Novel Protein Is Required for Normal Meiotic Homologous Recombination

Abstract: Recent studies of meiotic recombination in the budding yeast and the model plant Arabidopsis thaliana indicate that meiotic crossovers (COs) occur through two genetic pathways: the interference-sensitive pathway and the interference-insensitive pathway. However, few genes have been identified in either pathway. Here, we describe the identification of the PARTING DANCERS (PTD) gene, as a gene with an elevated expression level in meiocytes. Analysis of two independently generated transferred DNA insertional lines in PTD showed that the mutants had reduced fertility. Further cytological analysis of male meiosis in the ptd mutants revealed defects in meiosis, including reduced formation of chiasmata, the cytological appearance of COs. The residual chiasmata in the mutants were distributed randomly, indicating that the ptd mutants are defective for CO formation in the interference-sensitive pathway. In addition, transmission electron microscopic analysis of the mutants detected no obvious abnormality of synaptonemal complexes and apparently normal late recombination nodules at the pachytene stage, suggesting that the mutant's defects in bivalent formation were postsynaptic. Comparison to other genes with limited sequence similarity raises the possibility that PTD may present a previously unknown function conserved in divergent eukaryotic organisms.

Work Motivation and Job Satisfaction of Estonian Higher Officials

Abstract: Professional and efficient public administration means competent, motivated, and neutral public officers, working in system and dedicated to service of public interests. Various schools of public administration have so far differed in their approach to civil servants’ work motivation (e.g. Weber's and NMP approach). The goal of this study is to ascertain the work motivation and job satisfaction levels of Estonian higher officials, the factors influencing them (social-demographic as well as personal), and the ways of channeling them. The higher the work satisfaction, the less officials are motivated by material factors and good relations with their superiors. Stronger motivation comes from recognition and a sense of responsibility. All the average indicators of our Job Diagnostic Survey exceed the corresponding average results obtained in the USA, Finland, and Estonia. One notices a predominance of analyzer-type people among higher officials. The other predominant types are controller/analyzer and...

Two ice-core δ18O records from Svalbard illustrating climate and sea-ice variability over the last 400 years:

Abstract: Ice cores from the relatively low-lying ice caps in Svalbard have not been widely exploited in climatic studies owing to uncertainties about the effect of meltwater percolation. However, results from two new Svalbard ice cores, at Lomonosovfonna and Austfonna, have shown that with careful site selection, high-resolution sampling and multiple chemical analyses it is possible to recover ice cores from which part of the annual signals are preserved, despite the considerable meltwater percolation. The new Svalbard ice cores are positioned in different parts of Svalbard and cover the past 800 years. In this paper we focus on the last 400 years. The 6180 signals from the cores are qualitatively similar over most of the twentieth century, suggesting that they record the same atmospheric signal. Prior to AD 1920, the Austfonna ice core exhibits more negative 6180 values than Lomonosovfonna, although there are intermittent decadal-scale periods throughout the record with similar values. We suggest that the differences reflect the effect of the inversion layer during the winter. The pattern in the 6180 records is similar to the Longyearbyen airtemperature record, but on an annual level the correlation is low. The Austfonna record correlates well with the temperature record from the more distant and southwesterly located Jan Mayen. A comparison of the ice-core and sea-ice records from this period suggests that sea-ice extent and Austfonna 6180 are related over the past 400 years. This may reflect the position of the storm tracks and their direct influence on the relatively low-altitude Austfonna. Lomonosovfonna may be less sensitive to such changes and primarily record free atmospheric changes instead of variations in sea-ice extent, the latter is probably a result of its higher elevation.

The essence of dataflow programming

Abstract: We propose a novel, comonadic approach to dataflow (stream-based) computation. This is based on the observation that both general and causal stream functions can be characterized as coKleisli arrows of comonads and on the intuition that comonads in general must be a good means to structure context-dependent computation. In particular, we develop a generic comonadic interpreter of languages for context-dependent computation and instantiate it for stream-based computation. We also discuss distributive laws of a comonad over a monad as a means to structure combinations of effectful and context-dependent computation. We apply the latter to analyse clocked dataflow (partial stream based) computation.

CLIMATE OSCILLATIONS AS RECORDED IN SVALBARD ICE CORE ω18O RECORDS BETWEEN AD 1200 AND 1997

Abstract: We apply two different time series analytical tools to omega18O records from two Svalbard ice cores. One ice core is from Lomonosovfonna at 1250 ma.s.l. and the other from Austfonna at 750 m a.s.l. These cores are estimated to cover at least the past 800 years and have been dated using a combination of known reference horizons and glacial modelling. Wavelet analysis reveals low frequency oscillations on the 60-120-year scale on the lower elevation site Austfonna while the higher altitude site on Lomonosovfonna does not reveal such variability throughout the record. The second method, Significant Zero Crossing of Derivates (SiZer) does not resolve the low-frequency periodicity seen in the wavelet analysis. The low-frequency variability resolved by the wavelet analysis is similar to what has been found in various climate records including instrumental temperatures and tree-rings, and has been proposed as the most important oscillation for the observed trends in Arctic air temperatures.

Iteration and coiteration schemes for higher-order and nested datatypes

Abstract: This article studies the implementation of inductive and coinductive constructors of higher kinds (higher-order nested datatypes) in typed term rewriting, with emphasis on the choice of the iteration and coiteration constructions to support as primitive. We propose and compare several well-behaved extensions of System Fω with some form of iteration and coiteration uniform in all kinds. In what we call Mendler-style systems, the iterator and coiterator have a computational behavior similar to the general recursor, but their types guarantee termination. In conventional-style systems, monotonicity witnesses are used for a notion of monotonicity defined uniformly for all kinds. Our most expressive systems GMItω and GItω of generalized Mendler, resp. conventional (co)iteration encompass Martin, Gibbons and Bailey's efficient folds for rank-2 inductive types. Strong normalization of all systems considered is proved by providing an embedding of the basic Mendler-style system MItω into System Fω

New stability conditions via reflection coefficients of polynomials

Abstract: The geometry of stable discrete polynomials using their coefficients and reflection coefficients is investigated. Starting from so-called barycentric simplex some necessary stability conditions in terms of unions of polytopes are obtained by splitting the unit hypercube of reflection coefficients. Sufficient stability conditions in terms of linear covers of reflection vectors of a family of stable polynomials improve the Cohn stability criterion.

Photoelastic tomography for residual stress measurement in glass

Abstract: The paper describes an algorithm of photoelastic tomography and its application for residual stress measurement in glass articles of complicated shape. The algorithm is based on a linearized solution of the equations of integrated photoelasticity. The problem of tensor field to- mography is decomposed into several problems of scalar field tomogra- phy for normal stress components of the stress tensor. The method is implemented with an automated polariscope supplied with a rotary stage. Software for the control of tomographic measurements and for the calculation of the stress fields has been elaborated. Several examples illustrate application of the method. © 2005 Society of Photo-Optical Instrumenta-

Thermoanalytical study of acetylacetonate-modified titanium(IV) isopropoxide as a precursor for TiO2 films

Abstract: Thermal decomposition of dried TiO2 gel, obtained by hydrolysing acetylacetonate-modified titanium(IV) isopropoxide, was monitored by simultaneous TG/DTA/EGA-FTIR measurements in dynamic air up to 900°C. XRD and FTIR were employed to identify the solid reaction products. Thermal degradation of the TiO2 gel consists of five distinct mass loss steps, the total mass loss being 43.8p. EGA by FTIR revealed the release of H2O below 120°C; followed by acetone, isopropyl acetate and 1-propanol around 200-300°C, and finally CO and CO2 up to 550°C. Highly exothermic reaction at 410-550°C is caused by the combustion of carbon residues. Crystalline TiO2-anatase is formed around 500°C and TiO2-rutile close to 800°C.

Catalytic ozonation of m-dinitrobenzene

Abstract: The efficiency of catalytic ozonation with homogeneous (containing dissolved ions of Fe2+, Mn2+, Cu2+, Ni2+, Co2+, V5+, Cr3+, Mo6+) and heterogeneous (MnO2, Ni2O3, Fe2O3, CuO, Al2O3, CoO, V2O5, Cr2O3, MoO3, TiO2) catalysts and non-accompanied ozonation was compared for degradation of m-dinitrobenzene (m-DNB). Several transition metals in homogeneous and heterogeneous form improved significantly the ozone performance for degradation of m-DNB. This improvement was found to be due to supplementary formation of reactive species (hydroxyl radicals) and better ozone utilization. The effects observed were found to be strongly dependent on the treatment conditions.

Influence of sedimentological composition on OSL dating of glaciofluvial deposits: examples from Estonia

Abstract: We assess the suitability of luminescence (TL and OSL) dating techniques for establishing a precise Late Pleistocene chronology for the northern Baltic area, and show on the basis of the fine sand/coarse silt fraction of subaqueous deposits, how sedimentological composition influences the dates obtained. Turbidity, loading by fine suspended material, water depth, velocity of outwash streams and transport length, and also perhaps rapid night-time sedimentation and incorporation of older, unbleached particles are factors that variably influence the extent of bleaching of the luminescence signal, and thus, cause variability of dates obtained. Alongside reliable dates for "late-glacial" deposits between 11 000-15 000 OSL years BP, many entirely unreliable dates from 8 000 ą 300 to 114 000 ą 8 000 OSL years BP have been obtained. This means that the age determination of glaciofluvial deposits is extremely difficult in practice. This applies particularly to intermorainic sediments, the exact genesis of which is unknown. The paper is addressed to the investigators wishing to use luminescence dating techniques to establishing the Pleistocene chronostratigraphy of glaciofluvial deposits.

ZnS thin films deposited by spray pyrolysis technique

Abstract: ZnS thin films were prepared by spray pyrolysis technique using aqueous solutions of zinc chloride and thiourea at molar ratio of 1:1, 1:2 and 2:1. The films were characterized by XRD, FTIR, SEM and EDX. The phase composition, structure and morphology of sprayed films are controlled by both, the substrate temperature and the precursors molar ratio in the solution. The films deposited below 380 oC are amorphous and contain thermal decomposition residues of Zn(tu)2Cl2. Chlorine content becomes negligible at 500 oC, carbon and nitrogen in the form of zinc cyanamide are present in a trace amount up to 540 oC. Highly (002) orientated ZnS films with wurtzite structure and closely stoichiometric composition could be grown at temperatures close to 500 oC using Zn:S molar ratio of 1:2 in spray solution. The film consists of well-shaped hexagonal prisms with size of 100 nm. The spray of equimolar solution (Zn:S = 1:1) results in ZnS films with smaller grain size (∼25 nm) and slightly Zn-rich composition at 500 oC. Higher temperature (530 oC) is needed to grow the films with wurtzite structure. The use of Zn-rich (Zn/S > 1) solution results in the films consisting of ZnO and ZnS phases above 400 oC. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Proof obligations preserving compilation

Abstract: The objective of this work is to study the interaction between program verification and program compilation, and to show that the proof that a source program meets its specification can be reused to show that the corresponding compiled program meets the same specification. More concretely, we introduce a core imperative language, and a bytecode language for a stack-based abstract machine, and a non-optimizing compiler. Then we consider for both languages verification condition generators that operate on programs annotated with loop invariants and procedure specifications. In such a setting, we show that compilation preserves proof obligations, in the sense that the proof obligations generated for the source annotated program are the same that those generated for the compiled annotated program (using the same loop invariants and procedure specifications). Furthermore, we discuss the relevance of our results to Proof Carrying Code.