Success of electrocardioversion on the elderly

Background

There are two treatment strategies for medication-resistant atrial fibrillation (AF): rhythm control or rate control. It has been suggested that rate control is a valid strategy in well-tolerated AF because it does not result in increased mortality. We aimed to investigate the 1-year outcome of rhythm control in an elderly population of AF patients.

Method

The study was retrospective, using the data collected from electrocardioversions (ECV) of elderly patients and the data of their follow-up visits to the outpatient clinic. We looked for recurrence of AF within the first year after ECV. Furthermore, we investigated possible predictors of recurrence.

Results

From February 2008 till November 2011, 436 consecutive elderly patients admitted for ECV were included. The 1-year recurrence rate of AF was 51.3 %. We found that being female and a large left atrial diameter were independent predictors of recurrence.

Conclusion

The AF recurrence rate in our elderly population is comparable with reported AF recurrence rates in a younger population; we conclude that rhythm control can be regarded as the viable strategy in persistent AF in elderly patients.     

The burden of atrial fibrillation in the Netherlands

Background

Atrial fibrillation (AF) is the most common sustained atrial arrhythmia and it is independently associated with an increased morbidity and mortality. As a result of the high prevalence of AF, the economic and clinical impact of the disease is substantial. This study describes the economic and clinical impact of AF in the Netherlands.

Methods

Epidemiological data on AF in the Netherlands were projected on population estimates of the Netherlands in 2009 and combined with data on the cost of AF and its interventions.

Results

Overall prevalence of AF in the Netherlands is 5.5% in the population over 55 years, corresponding to about 250,000 AF patients. The prevalence increases with age, and the mean age of AF patients is 69.3 years. Incidence of AF in the Netherlands varies with age, from 1188 new cases in the age group of 55 to 59 up to 7074 new cases in the age group 75 to 79. Total new cases amounts to 45,085 patients per year in the Netherlands. Total costs of AF in the Netherlands are € 583 million, of which the majority (70%) were accounted for by hospitalisations and in-hospital procedures. Pharmacotherapeutic management of AF totalled € 17 million in the Netherlands in 2009.

Discussion

AF is a serious disease with a high clinical and economic burden, especially due to hospitalisations as a result of cardiovascular events. The number of patients with AF in the Netherlands is considerable and will increase with the ageing population in the future.     

Association between -T786C NOS3 polymorphism and resistant hypertension: a prospective cohort study

Background

Autonomic dysfunction appears to play a significant role in the development of atrial fibrillation (AF), and impaired heart rate recovery (HRR) during exercise treadmill testing (ETT) is a known marker for autonomic dysfunction. However, whether impaired HRR is associated with incident AF is unknown. We studied the association of impaired HRR with the development of incident AF, after controlling for demographic and clinical confounders.

Methods

We studied 8236 patients referred for ETT between 2001 and 2004, and without a prior history of AF. Patients were categorized by normal or impaired HRR on ETT. The primary outcome was the development of AF. Cox proportional hazards modeling was used to control for demographic and clinical characteristics. Secondary analyses exploring a continuous relationship between impaired HRR and AF, and exploring interactions between cardiac medication use, HRR, and AF were also conducted.

Results

After adjustment, patients with impaired HRR were more likely to develop AF than patients with normal HRR (HR 1.43, 95% confidence interval (CI) 1.06, 1.93). In addition, there was a linear trend between impaired HRR and AF (HR 1.05 for each decreasing BPM in HRR, 95% CI 0.99, 1.11). No interactions between cardiac medications, HRR, and AF were noted.

Conclusion

Patients with impaired HRR on ETT were more likely to develop new-onset AF, as compared to patients with normal HRR. These findings support the hypothesis that autonomic dysfunction mediates the development of AF, and suggest that interventions known to improve HRR, such as exercise training, may delay or prevent AF.     

Haplotype frequencies at the DRD2 locus in populations of the East European Plain

Background

A key to increasing the power of multilocus association tests is to reduce the number of degrees of freedom by suppressing noise from data. One of the difficulties is to decide how much noise to suppress. An often overlooked problem is that commonly used association tests based on genotype data cannot utilize the genetic information contained in spatial ordering of SNPs (see proof in the Appendix), which may prevent them from achieving higher power.

Results

We develop a score test based on wavelet transform with empirical Bayesian thresholding. Extensive simulation studies are carried out under various LD structures as well as using HapMap data from many different chromosomes for both qualitative and quantitative traits. Simulation results show that the proposed test automatically adjusts the level of noise suppression according to LD structures, and it is able to consistently achieve higher or similar powers than many commonly used association tests including the principle component regression method (PCReg).

Conclusion

The wavelet-based score test automatically suppresses the right amount of noise and uses the information contained in spatial ordering of SNPs to achieve higher power.     

Equivalence and noninferiority trials – are they viable alternatives for registration of new drugs? (III)

Objectives

Ximelagatran is a novel oral direct thrombin inhibitor. It has favorable pharmacodynamic properties, with a broad therapeutic range without the need for anticoagulation monitoring. We aimed to discover whether ximelagatran offers a genuine future replacement to warfarin for patients in persistent atrial fibrillation (AF).

Materials and methods

We provide an evidence-based review of the relative merits and disadvantages of warfarin and aspirin. We subsequently present an overview of the evidence for the utility of ximelagatran in the treatment of AF.

Results

Adjusted dose warfarin is recommended over aspirin for patients in AF at high risk of future stroke. Some of this benefit is partially offset by the higher bleeding risks associated with warfarin therapy. The SPORTIF III and V studies have shown that ximelagatran is not inferior to warfarin in the prevention of all strokes in patients with AF (both persistent and paroxysmal). This benefit was partially offset by the finding of a significant elevation of liver transaminases (>3 × normal) in 6% of patients.

Conclusions

Current data would suggest that ximelagatran might represent a future alternative to warfarin. The lack of need for anticoagulant monitoring has been partially offset by a need for regular monitoring of liver function. Further data from randomized clinical trials is clearly needed.     

Can pulsed ultrasound increase tissue damage during ischemia? A study of the effects of ultrasound on infarcted and non-infarcted myocardium in anesthetized pigs

Background

Natural history of paroxysmal atrial fibrillation (AF) is not very well documented. Clinical experience suggests that paroxysmal AF could progress to chronic AF with estimates ranging between 15 and 30% over a period of 1–3 years. We performed an epidemiologic study to elucidate the natural history of paroxysmal AF, this study estimated its incidence in a general practice setting, identified associated factors and analyzed the progression into chronic AF as well as the mortality rate.

Methods

Using the UK General Practice Research Database (GPRD), we identified patients aged 40–89 years with a first-recorded episode of paroxysmal AF during 1996. Risk factors were assessed using 525 incident paroxysmal AF cases confirmed by the general practitioner (GP) and a random sample of controls. We follow-up paroxysmal AF patients and estimated their mortality rate and progression to chronic AF.

Results

The incidence of paroxysmal AF was 1.0 per 1,000 person-years. Major risk factors for paroxysmal AF were age and prior valvular heart disease, ischaemic heart disease, heart failure and hyperthyroidism. During a mean follow-up of 2.7 years, 70 of 418 paroxysmal AF patients with complete information progressed to chronic AF. Risk factors associated with progression were valvular heart disease (OR 2.7, 95% CI 1.2–6.0) and moderate to high alcohol consumption (OR 3.0, 95% CI 1.1–8.0). Paroxysmal AF patients did not carry an increased risk of mortality, compared to an age and sex matched sample of the general population. There was a suggestion of a small increased risk among patients progressing to chronic AF (RR 1.5, 96% CI 0.8–2.9).

Conclusion

Paroxysmal AF is a common arrhythmia in the general practice setting, increasing with age and commonly associated with other heart diseases. It sometimes is the initial presentation and then progress to chronic AF. A history of valvular heart disease and alcohol consumption are associated with this progression.     

Negative predictive value of SPECT for the occurrence of MACE in a medium-sized clinic in the Netherlands

Background

Single-photon emission computed tomography (SPECT) is an important prognostic tool in evaluating coronary artery disease (CAD), with a high negative predictive value (NPV) for the occurrence of major adverse cardiac events (MACE). The prognostic value of SPECT is disputed in women, patients with atrial fibrillation (AF), diabetes, left bundle branch block (LBBB) and renal impairment.

Methods

Seven hundred sixty-two patients without prior history of CAD who had SPECT without perfusion deficits were followed for 2 years for MACE. Predictive variables for the occurrence of MACE were reviewed by Cox proportional hazard regression, considering clinical information, resting-ECG data and SPECT data.

Results

The NPV of SPECT for the occurrence of MACE within 2 years was 95.8 %. Multivariate Cox regression revealed male gender as the only significant predictor for the occurrence of MACE, besides a positive stress ECG at SPECT and a low LVEF. AF, LBBB, renal impairment and diabetes had no significant effect on the prognosis after normal SPECT.

Conclusion

SPECT with normal perfusion images has great NPV in a medium-sized clinic in the Netherlands, even in patients with LBBB, AF, diabetes and renal impairment. MACE-free survival, however, was negatively influenced by male gender; we therefore propose more caution in men.     

Routine versus aggressive upstream rhythm control for prevention of early atrial fibrillation in heart failure: background, aims and design of the RACE 3 study

Background

Rhythm control for atrial fibrillation (AF) is cumbersome because of its progressive nature caused by structural remodelling. Upstream therapy refers to therapeutic interventions aiming to modify the atrial substrate, leading to prevention of AF.

Objective

The Routine versus Aggressive upstream rhythm Control for prevention of Early AF in heart failure (RACE 3) study hypothesises that aggressive upstream rhythm control increases persistence of sinus rhythm compared with conventional rhythm control in patients with early AF and mild-to-moderate early systolic or diastolic heart failure undergoing electrical cardioversion.

Design

RACE 3 is a prospective, randomised, open, multinational, multicenter trial. Upstream rhythm control consists of angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers, mineralocorticoid receptor antagonists, statins, cardiac rehabilitation therapy, and intensive counselling on dietary restrictions, exercise maintenance, and drug adherence. Conventional rhythm control consists of routine rhythm control therapy without cardiac rehabilitation therapy and intensive counselling. In both arms, every effort is made to keep patients in the rhythm control strategy, and ion channel antiarrhythmic drugs or pulmonary vein ablation may be instituted if AF relapses. Total inclusion will be 250 patients. If upstream therapy proves to be effective in improving maintenance of sinus rhythm, it could become a new approach to rhythm control supporting conventional pharmacological and non-pharmacological rhythm control.     

A conformation ensemble approach to protein residue-residue contact

Background

Protein residue-residue contact prediction is important for protein model generation and model evaluation. Here we develop a conformation ensemble approach to improve residue-residue contact prediction. We collect a number of structural models stemming from a variety of methods and implementations. The various models capture slightly different conformations and contain complementary information which can be pooled together to capture recurrent, and therefore more likely, residue-residue contacts.

Results

We applied our conformation ensemble approach to free modeling targets from both CASP8 and CASP9. Given a diverse ensemble of models, the method is able to achieve accuracies of. 48 for the top L/5 medium range contacts and. 36 for the top L/5 long range contacts for CASP8 targets (L being the target domain length). When applied to targets from CASP9, the accuracies of the top L/5 medium and long range contact predictions were. 34 and. 30 respectively.

Conclusions

When operating on a moderately diverse ensemble of models, the conformation ensemble approach is an effective means to identify medium and long range residue-residue contacts. An immediate benefit of the method is that when tied with a scoring scheme, it can be used to successfully rank models.     

Real-time spectrum estimation–based dual-channel speech-enhancement algorithm for cochlear implant

Background

Improvement of the cochlear implant (CI) front-end signal acquisition is needed to increase speech recognition in noisy environments. To suppress the directional noise, we introduce a speech-enhancement algorithm based on microphone array beamforming and spectral estimation. The experimental results indicate that this method is robust to directional mobile noise and strongly enhances the desired speech, thereby improving the performance of CI devices in a noisy environment.

Methods

The spectrum estimation and the array beamforming methods were combined to suppress the ambient noise. The directivity coefficient was estimated in the noise-only intervals, and was updated to fit for the mobile noise.

Results

The proposed algorithm was realized in the CI speech strategy. For actual parameters, we use Maxflat filter to obtain fractional sampling points and cepstrum method to differentiate the desired speech frame and the noise frame. The broadband adjustment coefficients were added to compensate the energy loss in the low frequency band.

Discussions

The approximation of the directivity coefficient is tested and the errors are discussed. We also analyze the algorithm constraint for noise estimation and distortion in CI processing. The performance of the proposed algorithm is analyzed and further be compared with other prevalent methods.

Conclusions

The hardware platform was constructed for the experiments. The speech-enhancement results showed that our algorithm can suppresses the non-stationary noise with high SNR. Excellent performance of the proposed algorithm was obtained in the speech enhancement experiments and mobile testing. And signal distortion results indicate that this algorithm is robust with high SNR improvement and low speech distortion.     

Cognitive characteristics of older Japanese drivers

Background

Some causes of accidents among older drivers are: not paying attention to traffic signals; missing stop lines; and having to deal with and misjudging emergency situations. These causes of accidents reveal problems with attention and cognition. Such incidents are also related to driver perception and stress-coping mechanisms. It is important to examine the relation of stress reactions to attention and cognition as a factor influencing the causes of accidents commonly involving older drivers.

Finding

Subjects were 10 young drivers (23.3 ± 3.33 years) and 25 older drivers divided into two groups (older1 [60 to 65 years] and older2 [> 65 years]). This study revealed the correlation within driver stress inventory and driver coping questionnaires parameters was observed only in older drivers. They also needed a longer response time for Trail Making Test A and B. The factors affected the attention and cognition of older drivers by age but not driving experience itself, and coping parameters such as emotion focus, reappraisal, and avoidance were not included as stress inventory parameters. Being prone to fatigue was less for younger drivers than older drivers. Because they have shorter distances, shorter drive times, and no need for expressways, older drivers also had a significantly lower risk of thrill-seeking behaviour and more patience.

Conclusion

The intervention addressing their attention skills, aggressive feelings, and emotion focus should be considered. The technological improvements in cars will make older drivers feel safer and make driving easier which might lower the attention paid to the road, and regular driving training might be needed to assess and enhance their safety.     

The orosomucoid 1 protein (α1 acid glycoprotein) is overexpressed in odontogenic myxoma

Background

Odontogenic myxoma (OM) is a benign, but locally invasive, neoplasm occurring in the jaws. However, the molecules implicated in its development are unknown. OM as well as Dental Follicle (DF), an odontogenic tissue surrounding the enamel organ, is derived from ectomesenchymal/mesencyhmal elements. To identify some protein that could participate in the development of this neoplasm, total proteins from OM were separated by two-dimensional electrophoresis and the profiles were compared with those obtained from DF, used as a control.

Results

We identified eight proteins with differential expression; two of them were downregulated and six upregulated in OM. A spot consistently overexpressed in odontogenic myxoma, with a molecular weight of 44-kDa and a pI of 3.5 was identified as the orosomucoid 1 protein. Western blot experiments confirmed the overexpression of this protein in odontogenic myxoma and immunohistochemical assays showed that this protein was mainly located in the cytoplasm of stellate and spindle-shaped cells of this neoplasm.

Conclusion

Orosomucoid 1, which belongs to a group of acute-phase proteins, may play a role in the modulation of the immune system and possibly it influences the development of OM.     

Three-dimensional computed tomography overlay for pulmonary vein antrum isolation: Follow-up and clinical outcomes

Background

To facilitate the creation of circumferential lines in pulmonary vein (PV) antrum isolation, three-dimensional (3D) navigation systems are used widely. Alternatively, 3D reconstructions of the left atrium (LA) can be superimposed directly on fluoroscopy to guide ablation catheters and to mark ablation sites.

Methods

In 71 atrial fibrillation patients circumferential PV ablation was performed. 3D reconstructions of the LA were derived from contrast cardiac-computed tomography and circumferential PV isolation was performed. In subsequent ablation procedures, veins were re-isolated, and defragmentation or linear lesions were performed if necessary.

Results

Adequate 3D reconstructions were formed and registered to fluoroscopy in all patients. All veins, except 2 in one single patient, could be isolated, resulting in freedom of AF in 45 patients (63?%). In 19 patients a second procedure was performed, in which 2.7?±?1.1 PV per patient were re-isolated; in 3 patients a third procedure was performed. After follow-up of 15?±?8?months, 51 (91?%) of patients with paroxysmal and 10 (67?%) with persistent AF were free of AF.

Conclusions

The results of 3D overlay for circumferential PV isolation are good, although the reconduction rate and need for subsequent ablations remains high, and the outcomes of this technique appear to be equivalent to other mapping techniques.     

Predicting human splicing branchpoints by combining sequence-derived features and multi-label learning methods

Background

Alternative splicing is the critical process in a single gene coding, which removes introns and joins exons, and splicing branchpoints are indicators for the alternative splicing. Wet experiments have identified a great number of human splicing branchpoints, but many branchpoints are still unknown. In order to guide wet experiments, we develop computational methods to predict human splicing branchpoints.

Results

Considering the fact that an intron may have multiple branchpoints, we transform the branchpoint prediction as the multi-label learning problem, and attempt to predict branchpoint sites from intron sequences. First, we investigate a variety of intron sequence-derived features, such as sparse profile, dinucleotide profile, position weight matrix profile, Markov motif profile and polypyrimidine tract profile. Second, we consider several multi-label learning methods: partial least squares regression, canonical correlation analysis and regularized canonical correlation analysis, and use them as the basic classification engines. Third, we propose two ensemble learning schemes which integrate different features and different classifiers to build ensemble learning systems for the branchpoint prediction. One is the genetic algorithm-based weighted average ensemble method; the other is the logistic regression-based ensemble method.

Conclusions

In the computational experiments, two ensemble learning methods outperform benchmark branchpoint prediction methods, and can produce high-accuracy results on the benchmark dataset.

     

Morphological instability and cancer invasion: a 'splashing water drop' analogy

Tumor progression

In many (perhaps in all) tumor systems, a malignant cancer is preceded by a benign lesion. Most benign lesions do not transform to malignancy and many regress. The final transformative step to malignancy differs from the preceding steps in, among other things, that it often occurs in the absence of the original carcinogenic stimulus.

Mechanism of immunostimulation

Relatively low titers of specific immune reactants are known to stimulate, but cell-to-cell or cell-to-matrix interactions appear to be major inhibitors of tumor-growth. Therefore, it seems reasonable to hypothesize that the mechanism of immunostimulation may be an interference with cell-to-cell or cell-to-matrix communication by a sub-lethal immune-reaction.

Discussion

While the above hypothesis remains unproven, some evidence suggests that immunity may have a major facilitating effect on tumor growth especially at the time of malignant transformation. There is even some evidence suggesting that transformation in vivo may seldom occur in the absence of immunostimulation of the premalignant lesion. Positive selection by the immune reaction may be the reason that tumors are immunogenic.     

Mechanisms linking plant community properties to soil aggregate stability in an experimental grassland plant diversity gradient

Background and aims

Soil aggregate stability depends on plant community properties, such as functional group composition, diversity and biomass production. However, little is known about the relative importance of these drivers and the role of soil organisms in mediating plant community effects.

Methods

We studied soil aggregate stability in an experimental grassland plant diversity gradient and considered several explanatory variables to mechanistically explain effects of plant diversity and plant functional group composition. Three soil aggregate stability measures (slaking, mechanical breakdown and microcracking) were considered in path analyses.

Results

Soil aggregate stability increased significantly from monocultures to plant species mixtures and in the presence of grasses, while it decreased in the presence of legumes, though effects differed somewhat between soil aggregate stability measures. Using path analysis plant community effects could be explained by variations in root biomass, soil microbial biomass, soil organic carbon concentrations (all positive relationships), and earthworm biomass (negative relationship with mechanical breakdown).

Conclusions

The present study identified important drivers of plant community effects on soil aggregate stability. The effects of root biomass, soil microbial biomass, and soil organic carbon concentrations were largely consistent across plant diversity levels suggesting that the mechanisms identified are of general relevance.     

Adherence to cardioprotective medications and mortality among patients with diabetes and ischemic heart disease

Background

Atrial electrical remodeling has been shown to influence the outcome the outcome following cardioversion of atrial fibrillation (AF) in experimental studies. The aim of the present study was to find out whether a non-invasively measured atrial fibrillatory cycle length, alone or in combination with other non-invasive parameters, could predict sinus rhythm maintenance after cardioversion of AF.

Methods

Dominant atrial cycle length (DACL), a previously validated non-invasive index of atrial refractoriness, was measured from lead V1 and a unipolar oesophageal lead prior to cardioversion in 37 patients with persistent AF undergoing their first cardioversion.

Results

32 patients were successfully cardioverted to sinus rhythm. The mean DACL in the 22 patients who suffered recurrence of AF within 6 weeks was 152 ± 15 ms (V1) and 147 ± 14 ms (oesophagus) compared to 155 ± 17 ms (V1) and 151 ± 18 ms (oesophagus) in those maintaining sinus rhythm (NS). Left atrial diameter was 48 ± 4 mm and 44 ± 7 mm respectively (NS). The optimal parameter predicting maintenance of sinus rhythm after 6 weeks appeared to be the ratio of the lowest dominant atrial cycle length (oesophageal lead or V1) to left atrial diameter. This ratio was significantly higher in patients remaining in sinus rhythm (3.4 ± 0.6 vs. 3.1 ± 0.4 ms/mm respectively, p = 0.04).

Conclusion

In this study neither an index of atrial refractory period nor left atrial diameter alone were predictors of AF recurrence within the 6 weeks of follow-up. The ratio of the two (combining electrophysiological and anatomical measurements) only slightly improve the identification of patients at high risk of recurrence of persistent AF. Consequently, other ways to asses electrical remodeling and / or other variables besides electrical remodeling are involved in determining the outcome following cardioversion.     

Wavelets filtering for classification of very noisy electron microscopic single particles images- application on structure determination of VP5-VP19C recombinant

Background

Images of frozen hydrated [vitrified] virus particles were taken close-to-focus in an electron microscope containing structural signals at high spatial frequencies. These images had very low contrast due to the high levels of noise present in the image. The low contrast made particle selection, classification and orientation determination very difficult. The final purpose of the classification is to improve the signal-to-noise ratio of the particle representing the class, which is usually the average. In this paper, the proposed method is based on wavelet filtering and multi-resolution processing for the classification and reconstruction of this very noisy data. A multivariate statistical analysis (MSA) is used for this classification.

Results

The MSA classification method is noise dependant. A set of 2600 projections from a 3D map of a herpes simplex virus -to which noise was added- was classified by MSA. The classification shows the power of wavelet filtering in enhancing the quality of class averages (used in 3D reconstruction) compared to Fourier band pass filtering. A 3D reconstruction of a recombinant virus (VP5-VP19C) is presented as an application of multi-resolution processing for classification and reconstruction.

Conclusion

The wavelet filtering and multi-resolution processing method proposed in this paper offers a new way for processing very noisy images obtained from electron cryo-microscopes. The multi-resolution and filtering improves the speed and accuracy of classification, which is vital for the 3D reconstruction of biological objects. The VP5-VP19C recombinant virus reconstruction presented here is an example, which demonstrates the power of this method. Without this processing, it is not possible to get the correct 3D map of this virus.

     

A supervised visual model for finding regions of interest in basal cell carcinoma images

Background

Expectation maximizing (EM) is one of the common approaches for image segmentation.

Methods

an improvement of the EM algorithm is proposed and its effectiveness for MRI brain image segmentation is investigated. In order to improve EM performance, the proposed algorithms incorporates neighbourhood information into the clustering process. At first, average image is obtained as neighbourhood information and then it is incorporated in clustering process. Also, as an option, user-interaction is used to improve segmentation results. Simulated and real MR volumes are used to compare the efficiency of the proposed improvement with the existing neighbourhood based extension for EM and FCM.

Results

the findings show that the proposed algorithm produces higher similarity index.

Conclusions

experiments demonstrate the effectiveness of the proposed algorithm in compare to other existing algorithms on various noise levels.     

Practical recommendations for supporting agricultural decisions through life cycle assessment based on two alternative views of crop production: the example of organic conversion

Purpose

Earlier studies on agricultural life cycle assessment recommend that practitioners use two functional units—product weight and land area—because agriculture entails commodity production and land use. However, there are still ambiguities in this approach from the perspective of decision support. The purpose of this paper is to provide recommendations to support farming conversion decisions on the basis of a framework constructed on two alternative views of agricultural production. Organic conversion of arable farming is selected as a case study.

Methods

Four types of conversion were constructed on the basis of land-oriented expression, in which inputs into and outputs from land were depicted, and product-oriented expression, in which inputs into and outputs from products were depicted. Then, the frequencies for each type were counted using LCI databases and data from journal papers.

Results

The results can be summarized as follows: (1) trade-off conversion, in which improvements in environmental impacts per area unit are involved in decrease of yield per area unit, is common. (2) Conversion tended to be efficient; that is, environmental impacts per product unit tended to improve. (3) Within trade-off conversion, the conversion tended to be efficient. (4) When conversion was efficient, there were trade-offs.

Conclusions

Since the results for one expression were not always derivable from the results for another expression, the recommendation of this study is to use the two expressions complementarily, knowing that win–win conversion is rare. In addition, there is a general recommendation to use decision criteria rather than trying to make decisions on the basis of multiple functional units because comparisons based on the two functional units are not on the same level.