Experimental on-farm trials data of faba bean and wheat intercropping field validation in Lebanon and Morocco.

This data paper describes the content of four datasets collected by the International Center for Agricultural Research in the Dry Areas (ICARDA) as a partner in the project "Designing InnoVative plant teams for Ecosystem Resilience and agricultural Sustainability (DIVERSify)" with the objective of assessing the feasibility of faba bean-wheat mixture in Mediterranean environments under diverse rainfed conditions. Data was collected during the trials conducted in Kfardan-Lebanon during 2017/2018 where 40 faba bean varieties were evaluated as sole and as mixture with 2 wheat cultivars 'Margherita' and 'Miki' and during 2018/2019 where 40 faba bean varieties and one durum wheat cultivar 'Margherita' were evaluated under low rainfall environments. Trials were also conducted in Tal Amara-Lebanon during 2019/2020 where 20 faba bean lines and one durum wheat cultivar 'Margherita' were evaluated under high rainfall environments and in Marchouch-Morocco during 2019/2020 where 7 faba bean lines with 3 cultivars and one durum wheat cultivar 'Margherita' were evaluated under extremely low rainfall environments. A detailed list of the different biological traits collected for wheat and faba bean is found in the specification table in this article. The Kfardan 2018/ 2019, Tal Amara and Marchouch data is related to the conference paper "Performance of faba bean-wheat mixture under diverse Mediterranean environments" [1].

International Winter Wheat nurseries data: Facultative and Winter Wheat Observation Nurseries and International Winter Wheat yield trials for semi-arid and irrigated conditions.

This data paper describes the content of 16 datasets collected under the International Winter Wheat Improvement Program (IWWIP), an alliance between Turkey-CIMMYT-ICARDA (TCI), during the 2015-2016, 2016-2017, 2017-2018 and 2018-2019 seasons. Data was collected from the Facultative and Winter Wheat Observation Nursery (FAWWON) and the International Winter Wheat Yield Trials (IWWYT) conducted under semi-arid and irrigated conditions across different countries. Data on all nurseries was collected during the growing season by IWWIP's team and cooperators in their local environments. It was compiled at the end of the wheat season by IWWIP's team. Multi-locational data can be used to select advanced lines that fit to collaborators' growing environment. The selected germplasm can either be used as a parent in their breeding programs or be released as a variety in their country.

Data on how tree planting and management practices influence tree seedling survival in Kenya and Ethiopia.

Understanding which trees farmers prefer, what determines their survival and enhancing farmer knowledge of tree management is key to increasing tree cover in agricultural landscapes. This article presents data on tree seedling survival under different tree planting and management practices in Kenya and Ethiopia. Data were collected from 1600 households across three Counties in Kenya and 173 households across four Woredas in Ethiopia, using a structured questionnaire which was administered through the Open Data Kit. Data on seedling survival were collected at least six months after tree seedlings were planted. To understand how planting and management practices influence tree planting across the different socioeconomic and biophysical contexts, both household level and individual tree level data were collected. Household level data included socio-economic and biophysical characteristics of the households while tree specific data included when the tree seedling was planted, where it was planted, the management practices employed and whether surviving. The datasets described in this article help understand which options confer the best chance survival for the planted seedlings and in which socio-economic and biophysical contexts they are most successful.

Quantification of not-dipolar components of atrial depolarization by principal component analysis of the P-wave.

BACKGROUND: Principal component analysis (PCA) of the T-wave has been demonstrated to quantify the dipolar and not-dipolar components of the ventricular activation, the latter reflecting repolarization heterogeneity. Accordingly, the PCA of the P-wave could help in analyzing the heterogeneous propagation of sinus impulses in the atria, which seems to predispose to fibrillation. AIM: The aim of this study is to perform the PCA of the P-wave in patients prone to atrial fibrillation (AF). METHODS: PCA is performed on P-waves extracted by averaging technique from ECG recordings acquired using a 32-lead mapping system (2048 Hz, 24 bit, 0-400 Hz bandwidth). We extracted PCA parameters related to the dipolar and not dipolar components of the P-wave using the first 3 eigenvalues and the cumulative percent of variance explained by the first 3 PCs (explained variance EV). RESULTS AND CONCLUSIONS: We found that the EV associated to the low risk patients is higher than that associated to the high risk patients, and that, correspondingly, the first eigenvalue is significantly lower while the second one is significantly higher in the high risk patients respect to the low risk group. Factor loadings showed that on average all leads contribute to the first principal component.

Radiofrequency identification and medical devices: the regulatory framework on electromagnetic compatibility. Part I: medical devices.

Radiofrequency identification (RFID) technology has acheived significant success and has penetrated into various areas of healthcare. Several RFID-based applications are used in various modalities with the ultimate aim of improving patient care. When a wireless technology is used in a healthcare environment, attention must be paid to the potential risks deriving from its use; one of the most important being electromagnetic interference with medical devices. In this paper, the regulatory framework concerning the electromagnetic compatibility between RFID and medical devices is analyzed to understand whether and how the application of the current standards allows for the effective control of the risks of electromagnetic interference.

Radiofrequency identification and medical devices: the regulatory framework on electromagnetic compatibility. Part II: active implantable medical devices.

The number and the types of electromagnetic emitters to which patients with active implantable medical devices (AIMD) are exposed to in their daily activities have proliferated over the last decade. Radiofrequency identification (RFID) is an example of wireless technology applied in many fields. The interaction between RFID emitters and AIMD is an important issue for patients, industry and regulators, because of the risks associated with such interactions. The different AIMDs refer to different standards that address the electromagnetic immunity issue in different ways. Indeed, different test setups, immunity levels and rationales are used to guarantee that AIMDs are immune to electromagnetic nonionizing radiation. In this article, the regulatory framework concerning electromagnetic compatibility between RFID systems and AIMDs is analyzed to understand whether and how the application of the current AIMD standards allows for the effective control of the possible risks associated with RFID technology.

Daily distribution of atrial arrhythmic episodes in sick sinus syndrome patients: implications for atrial arrhythmia monitoring.

AIMS: Disorders such as paroxysmal atrial fibrillation (AF) and atrial tachyarrhythmias (AT) are difficult to investigate because of their intermittent, and sometimes asymptomatic, nature. The aim of this study was to investigate the daily temporal distribution of AT/AF episodes--onset and occurrence--by analysing data from 250 pacemaker-implanted, brady-tachy syndrome patients who have been enrolled in the Burden II Study. METHODS AND RESULTS: Data were analysed accounting for the mode switch list which includes date, time, and duration of each mode switch episode. Chi-squared tests for goodness of fit were used to determine whether AT/AF episode were uniformly distributed. The population analysed in the present study suggests the occurrence of a circadian rhythm of paroxysmal AF episodes, similar to that described for other cardiovascular diseases, with clustering of events in the morning from 08:00 and (to a lesser degree) in the afternoon (03:00 to 18:00). The relative risk of AT/AF onset is 13% higher during daytime, 40% lower at night (P < 0.000001). CONCLUSION: The use of monitoring devices based on daily electrocardiogram (ECG) recording could be optimized with these data, thus increasing the probability to detect AT/AF episodes.

On the resolution of ECG acquisition systems for the reliable analysis of the P-wave.

The analysis of the P-wave on surface ECG is widely used to assess the risk of atrial arrhythmias. In order to provide reliable results, the automatic analysis of the P-wave must be precise and reliable and must take into account technical aspects, one of those being the resolution of the acquisition system. The aim of this note is to investigate the effects of the amplitude resolution of ECG acquisition systems on the P-wave analysis. Starting from ECG recorded by an acquisition system with a less significant bit (LSB) of 31 nV (24 bit on an input range of 524 mVpp), we reproduced an ECG signal as acquired by systems with lower resolution (16, 15, 14, 13 and 12 bit). We found that, when the LSB is of the order of 128 µV (12 bit), a single P-wave is not recognizable on ECG. However, when averaging is applied, a P-wave template can be extracted, apparently suitable for the P-wave analysis. Results obtained in terms of P-wave duration and morphology revealed that the analysis of ECG at lowest resolutions (from 12 to 14 bit, LSB higher than 30 µV) could lead to misleading results. However, the resolution used nowadays in modern electrocardiographs (15 and 16 bit, LSB <10 µV) is sufficient for the reliable analysis of the P-wave.

Role of the lead structure in MRI-induced heating: In vitro measurements on 30 commercial pacemaker/defibrillator leads.

MRI-induced heating on endocardial leads is a serious concern for the safety of patients with implantable pacemakers or cardioverter-defibrillator. The lead heating depends on many factors and its amount is largely variable. In this study, we investigated the role of those structural properties of the lead that are reported on the accompanying documents of the device: (1) fixation modality (active vs. passive); (2) number of electrodes (unipolar vs. bipolar); (3) length; (4) tip surface; and (5) tip and ring resistance. In vitro temperature and specific absorption rate measurements on 30 leads (27 pacemakers, three implantable cardioverter-defibrillator leads) exposed to the radiofrequency field typical of a 1.5 T MRI scanner are presented. The data show that each lead has its own attitude to radiofrequency-induced heating and that the information that is available in the accompanying documents of the pacemaker is not sufficient to explain such attitude. Even if combined with that of the implant geometry, this information is still not sufficient to estimate the amount of heating due to the exposure to the radiofrequency field during MRI examination.

A multiscale graph theoretical approach to gene regulation networks: a case study in atrial fibrillation.

The changes in between gene expression correlation structure induced in heart tissue by atrial fibrillation are studied by means of a graph theoretical approach. As expected by general statistical mechanics principles, the disease increases the general connectivity of the gene regulation network; the multiscale character of the analysis allows us to get both a general appreciation of regulation network connectivity and the sketching of a biological interpretation of the studied disease. The presence of a still largely unknown, scale invariant, global correlation field encompassing the entire genome is demonstrated as well.

RFID in healthcare environment: electromagnetic compatibility regulatory issues.

Several wireless technology applications (RFID, WiFi, GSM, GPRS) have been developed to improve patient care, reaching a significant success and diffusion in healthcare. Given the potential development of such a technology, care must be paid on the potential risks deriving from the use of wireless device in healthcare, among which one of the most important is the electromagnetic interference with medical devices. The analysis of the regulatory issues concerning the electromagnetic compatibility of medical devices is essential to evaluate if and how the application of the current standards allows an effective control of the possible risks associated to the electromagnetic interference on medical devices.

P-wave characteristics after electrical external cardioversion: predictive indexes of relapse.

Atrial fibrillation (AF) is the most common arrhythmia in the western countries and accounts for hundred thousand strokes per year. Electrocardiographic characteristics of AF have been demonstrated to help identify patients at risk of developing AF. Prolonged and highly fragmented P-waves have been observed in patients prone to AF, and time-domain. Morphological characteristics of the P-wave from surface ECG recordings turned out to significantly distinguish patients at risk of AF. The aim of this study is to evaluate the morphological and time-domain characteristics of the P-wave in patients with AF relapse after cardioversion, respect to patients without. 14 patients who underwent successful electrical cardioversion for persistent AF were enrolled. Five minute ECG recordings were performed for each subject, immediately post-successful cardioversion. ECG signals were acquired by using a 16-lead mapping system for high-resolution biopotential measurements (sample frequency 2 kHz, 31 nV resolution, 0-400 Hz bandwidth). From the 16 recordings, a standard 12-lead ECG was derived and analyzed in terms of signal-averaged P-wave. Time-domain and mor-phological characteristics were estimated from the averaged P-waves of each lead. Time-domain features were quantified as: maximum P-wave duration in any of the 12 leads (Pmax), minimum P-wave duration in any of the leads (Pmin), P-wave dispersion (Pdisp=Pmax-Pmin), and Pindex (standard devia-tion of P-wave duration in any of the 12 leads). Morphological characteristics were extracted from a Gaussian function-based model of the P-wave as: average model order (Nav), maximum number of zero-crossing (PCmax), and maximum and average number of maxima and minima (FCImax and FCIav) in any of the leads. The results obtained so far indicate that the morphological and time-domain characteristics distinguish between patients with AF relapse and patients without.

A systems biology strategy on differential gene expression data discloses some biological features of atrial fibrillation.

Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with extensive structural, contractile, and electrophysiological remodeling. In this manuscript we re-analyzed gene expression data from a microarray experiment on AF patients and control tissues, using a new paradigm based on a posteriori unsupervised strategy in which the discrimination of patients comes out from purely syntactical premises. This paradigm, more adherent to biological reality where genes work in highly connected networks, allowed us to get both a very precise patients/control discrimination and the discovery of cell adhesion/tissue modeling and inflammation processes as the main dimensions of AF.

Numerical model for estimating RF-induced heating on a pacemaker implant during MRI: experimental validation.

MRI may cause tissue heating in patients implanted with pacemakers (PMs) or cardioverters/defibrillators. As a consequence, these patients are often preventatively excluded from MRI investigations. The issue has been studied for several years now, in order to identify the mechanisms involved in heat generation, and define safety conditions by which MRI may be extended to patients with active implants. In this sense, numerical studies not only widen the range of experimental measurements, but also model a realistic patient's anatomy on which it is possible to study individually the impact of the many parameters involved. In order to obtain reliable results, however, each and every numerical analysis needs to be validated by experimental evidence. Aim of this paper was to design and validate through experimental measurements, an accurate numerical model, which was able to reproduce the thermal effects induced by a birdcage coil on human tissues containing a metal implant, specifically, a PM. The model was then used to compare the right versus left pectoral implantation of a PM, in terms of power deposited at the lead tip. This numerical model may also be used as reference for validating simpler models in terms of computational effort.

Autonomic function during closed loop stimulation and fixed rate pacing: heart rate variability analysis from 24-hour Holter recordings.

AIM: Aim of this retrospective study was to analyze the effect of closed-loop stimulation (CLS) and DDD pacing mode on autonomic balance, and to evaluate heart rate variability (HRV) during CLS stimulation. METHODS AND MATERIALS: Autonomic balance was estimated by a 24-hour HRV analysis of paced and spontaneous beats in patients implanted with a dual-chamber pacemaker (Inos(2+) CLS-Biotronik GmbH, Berlin, Germany) and randomly assigned to CLS or DDD pacing mode. Patients underwent two 24-hour electrocardiogram Holter recordings at the end of each 3-month pacing mode period. Each Holter recording was automatically scanned to extract sequences of consecutive beats of the same type [atrial paced (Ap)-sequence and atrial spontaneous (As)-sequence], lasting at least 130 beats. RESULTS: Eight hundred and ten sequences were extracted from 15 patients, and the following spectral parameters were evaluated during both CLS and DDD mode: the total power (variance), the absolute and percentage (relative to the total power) powers of the low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, 0.15-0.4 Hz) components, as well as the LF/HF power ratio. DISCUSSION: The two main findings of this study were: in all the patients, CLS seems to mimic short-term physiological HRV, although the variability (total power) was lower than that relative to the spontaneous beats; the HRV of the spontaneous beats had an higher LF/HF when the pacemaker was programmed as DDD respect to CLS, consistent with a shift toward sympathetic predominance.

Effect of high-pass filtering on ECG signal on the analysis of patients prone to atrial fibrillation.

The aim of this study was to assess the effect of filtering techniques on the time-domain analysis of the ECG. Multi-lead ECG recordings obtained from chronic atrial fibrillation (AF) patients after successful external cardioversion have been acquired. Several high-pass filtering techniques and three cut-off frequency values were used: Bessel and Butterworth four-pole and two-pole bidirectional and unidirectional filters, at 0.01, 0.05 and 0.5 Hz low cut-off frequency. As a reference, a beat-by-beat linear piecewise interpolation was used to remove baseline wander, on each P-wave. Results show that ECG filtering affects the estimation of P-wave duration in a manner that depends upon the type of filter used: particularly, the bidirectional filters caused negligible variation of P-wave duration, while unidirectional ones provoked an increase higher than 8%.

A novel, user-friendly step counter for home telemonitoring of physical activity.

Step counting is an important index of motion in telemonitoring. We have developed a wearable system based on a device with a force-sensing resistor. This is affixed at the calf gastrocnemius level to monitor the muscular expansion related to the gait. The gastrocnemius expansion measurement unit (GEMU) was tested on three subjects at Level 2 of the Tinetti test of unbalance, who performed five repetitions of 100 steps at two different speeds (normal and slow). The mean error was less than 0.5%. The GEMU also performed better than an accelerometer unit, which is normally considered to be the best solution for this disability. The system can be integrated into a routine home-care application based on a GSM home-care unit.

In vitro investigation of pacemaker lead heating induced by magnetic resonance imaging: role of implant geometry.

PURPOSE: To evaluate the effect of the geometry of implantable pacemakers (PMs) on lead heating induced by magnetic resonance imaging (MRI). MATERIALS AND METHODS: In vitro experiments were conducted with two different setups, using fluoroptic probes to measure the temperature increase. The first experiment consisted of a rectangular box filled with a gelled saline and a pacemaker with its leads. This box was exposed in an MRI birdcage coil to a sinusoidal 64-MHz field with a calibrated whole-body specific absorption rate (WB-SAR) of 1 W/kg. The highest SAR and temperature increase (3000 W/kg, 12 degrees C) occurred for the implant configuration having the largest area. The second experimental setup consisted of a human-shaped torso filled with gelled saline. In this setup the PM and its lead were exposed to a real MRI scanner, using clinical sequences with WB-SAR up to 2 W/kg. RESULTS: We found that higher heating occurs for configurations with longer exposed lead lengths and that right chest PMs showed the highest temperature and local SAR (11.9 degrees C, 2345 W/kg), whereas the left chest PMs were less heated (6.3 degrees C, 1362 W/kg). Implant geometry, exposed lead length, and lead area must be considered in the wide variation of temperature increases induced by MRI. CONCLUSIONS: The amount of MRI-induced lead tip heating depends strongly on implant geometry, particularly the lead area, exposed lead length, and position of the implant in the phantom. Critical lead tip heating was found for the longer leads. Therefore, to minimize MRI-induced lead tip heating, the PM lead should be as short as possible.

Time-domain and morphological analysis of the P wave. Part II: effects of atrial pacing on P-wave features.

BACKGROUND: The aim of this study was to compare time-domain and morphological descriptors of paced and spontaneous P wave in patients prone to atrial fibrillation (AF). METHODS: Nineteen patients (nine women, aged 72 +/- 10 years) affected by paroxysmal AF and implanted with dual-chamber pacemakers (PM) were studied. Two 5-minute recordings were performed during spontaneous and paced rhythm. Electrocardiogram (ECG) signals were acquired using a 32-lead mapping system. Patients were grouped into two classes: no previous AF and previous AF groups, according to the number of AF episodes in the 6 months before the analysis. RESULTS AND CONCLUSION: During atrial pacing P wave appeared prolonged and morphologically more complex with respect to sinus rhythm. We also found that in patients at lower risk for AF, the atrial pacing changes the atrial activation to a greater extent than in patients at higher risk for AF. Finally, all time-domain and morphological descriptors of the P wave except one succeed in discriminating "no previous AF" and "previous AF" patients in spontaneous rhythm, while no significant differences have been observed during pacing for any parameters.

Time-domain and morphological analysis of the P-wave. Part I: Technical aspects for automatic quantification of P-wave features.

INTRODUCTION: Time-domain and morphological analysis of P-wave from surface electrocardiogram has been extensively used to identify patients prone to atrial arrhythmias, especially atrial fibrillation (AF). However, since no standard procedure exists for P-wave preprocessing, standardization of cut-off values for P-wave duration and morphological features is difficult. This study is a methodological investigation of P-wave preprocessing procedures for automatic time-domain and morphological analysis. METHODS: We compared, on simulated and real data, the P-wave template obtained applying three alignment algorithms with that obtained without alignment, in terms of template error, shift error, P-wave duration, and morphological parameters. We also proposed automatic algorithms for estimation of P-wave duration. RESULTS: We found that alignment is necessary for a reliable extraction of P-wave template by the averaging procedure, in order to perform time-domain and morphological analysis. On simulated and real data, the error on P-wave duration can be as high as 30 ms on a template obtained without alignment; if alignment procedure is performed, the error on P-wave duration is negligible. Analogously, morphological features are correctly estimated only on a P-wave template obtained with P-waves alignment. We also found that the proposed algorithm for the automatic estimation of the P-wave duration gave reliable results.