Stronger Coherence Research Articles

A modified feedforward-feedback time-frequency domain hybrid algorithm for multichannel active road noise control system

Multi-channel Active Road Noise Control (ARNC) systems require numerous adaptive filters to reduce noise at multiple positions inside the vehicle. However, road noise conditions are more complex, and the correlation between the reference signals and the target noise is often poor. When the driving conditions become slightly complex, the correlation between the reference signal and the target noise is often poor. As a result, traditional road noise control algorithms applied to multi-channel ARNC systems often suffer from high computational cost and poor noise reduction performance in non-steady-state and high-speed driving conditions. To address this issue,a reference signal selection method based on the genetic algorithm (GA) is proposed to obtain a reference signals combination with stronger coherence. On this basis, we introduce the time–frequency domain structure into the forward-feedback hybrid algorithm and a multi-channel time–frequency domain hybrid algorithm with a novel variable step size method (VSS-TF-HANC) is proposed in this paper.The feedforward part adopts a time–frequency domain structure and introduces a novel variable step-size strategy to reduce computational complexity and improve noise reduction performance. The feedback part adopts a control system based on the Internal Model Control (IMC) architecture to attenuate the interior noise components that have a strong response but poor correlation with the reference signals. Simulation results demonstrate that the proposed algorithm achieves excellent control results under complex driving conditions, with significantly better noise reduction performance compared to the control algorithms that solely employ the feedforward structure, while also exhibiting low computational cost.

Cholinergic and behavior-dependent beta and gamma waves are coupled between olfactory bulb and hippocampus.

Olfactory oscillations may enhance cognitive processing through coupling with beta (β, 15-30 Hz) and gamma (γ, 30-160 Hz) activity in the hippocampus (HPC). We hypothesize that coupling between olfactory bulb (OB) and HPC oscillations is increased by cholinergic activation in control rats and is reduced in kainic-acid-treated epileptic rats, a model of temporal lobe epilepsy. OB γ2 (63-100 Hz) power was higher during walking and immobility-awake (IMM) compared to sleep, while γ1 (30-57 Hz) power was higher during grooming than other behavioral states. Muscarinic cholinergic agonist pilocarpine (25 mg/kg ip) with peripheral muscarinic blockade increased OB power and OB-HPC coherence at β and γ1 frequency bands. A similar effect was found after physostigmine (0.5 mg/kg ip) but not scopolamine (10 mg/kg ip). Pilocarpine increased bicoherence and cross-frequency coherence (CFC) between OB slow waves (SW, 1-5 Hz) and hippocampal β, γ1 and γ2 waves, with stronger coherence at CA1 alveus and CA3c than CA1 stratum radiatum. Bicoherence further revealed a nonlinear interaction of β waves in OB with β waves at the CA1-alveus. Beta and γ1 waves in OB or HPC were segregated at one phase of the OB-SW, opposite to the phase of γ2 and γ3 (100-160 Hz) waves, suggesting independent temporal processing of β/γ1 versus γ2/γ3 waves. At CA1 radiatum, kainic-acid-treated epileptic rats compared to control rats showed decreased theta power, theta-β and theta-γ2 CFC during baseline walking, decreased CFC of HPC SW with γ2 and γ3 waves during baseline IMM, and decreased coupling of OB SW with β and γ2 waves at CA1 alveus after pilocarpine. It is concluded that β and γ waves in the OB and HPC are modulated by a slow respiratory rhythm, in a cholinergic and behavior-dependent manner, and OB-HPC functional connectivity at β and γ frequencies may enhance cognitive functions.

Tunnel environment noise suppression by SVD-DSW method

There is strong random noise in seismic records of tunnel seismic advance detection, which makes it difficult to obtain the underground lithology information in front of tunnel face accurately. Aiming at the problem that random noise is difficult to suppress in tunnel environment, a method of SVD-DSW is proposed in our research. Different from the directional seismic wave method, the proposed method is to stack the target signal after leveling. Then, the target signal with stronger coherence is extracted by singular value decomposition and target signal reconstruction, and finally reverse correct the extracted coherent signal to get the target signal. Simulation results and field data analysis show that the SVD-ICA theoretical approach is feasible for improving the SNR of the target signal in three-component seismogram, which is of great significance to increase detection range and resolution of tunnel seismic advance prediction.

Reynolds-number scaling of wall-pressure–velocity correlations in wall-bounded turbulence

Wall-pressure fluctuations are a practically robust input for real-time control systems aimed at modifying wall-bounded turbulence. The scaling behaviour of the wall-pressure–velocity coupling requires investigation to properly design a controller with such input data so that it can actuate upon the desired turbulent structures. A comprehensive database from direct numerical simulations (DNS) of turbulent channel flow is used for this purpose, spanning a Reynolds-number range $Re_\tau \approx 550\unicode{x2013}5200$ . Spectral analysis reveals that the streamwise velocity is most strongly coupled to the linear term of the wall pressure, at a Reynolds-number invariant distance-from-the-wall scaling of $\lambda _x/y \approx 14$ (and $\lambda _x/y \approx 8$ for the wall-normal velocity). When extending the analysis to both homogeneous directions in $x$ and $y$ , the peak coherence is centred at $\lambda _x/\lambda _z \approx 2$ and $\lambda _x/\lambda _z \approx 1$ for $p_w$ and $u$ , and $p_w$ and $v$ , respectively. A stronger coherence is retrieved when the quadratic term of the wall pressure is concerned, but there is only little evidence for a wall-attached-eddy type of scaling. An experimental dataset comprising simultaneous measurements of wall pressure and velocity complements the DNS-based findings at one value of $Re_\tau \approx 2$ k, with ample evidence that the DNS-inferred correlations can be replicated with experimental pressure data subject to significant levels of (acoustic) facility noise. It is furthermore shown that velocity-state estimations can be achieved with good accuracy by including both the linear and quadratic terms of the wall pressure. An accuracy of up to 72 % in the binary state of the streamwise velocity fluctuations in the logarithmic region is achieved; this corresponds to a correlation coefficient of $\approx$ 0.6. This thus demonstrates that wall-pressure sensing for velocity-state estimation – e.g. for use in real-time control of wall-bounded turbulence – has merit in terms of its realization at a range of Reynolds numbers.

How can the European Common Agricultural Policy help halt biodiversity loss? Recommendations by over 300 experts

AbstractThe European Union's Common Agricultural Policy (CAP) has not halted farmland biodiversity loss. The CAP post‐2023 has a new ‘‘Green Architecture,’’ including the new ‘‘Eco‐scheme’’ instrument. How can this new Green Architecture help tackle the biodiversity crisis? Through 13 workshops and an online survey, over 300 experts from 23 European Member States addressed this question.From experts’ contributions, key principles for success include preserving and restoring (semi)natural elements and extensive grasslands; improving spatial planning and landscape‐scale implementation, including through collective actions; implementing result‐based approaches; and improved knowledge exchange. To maximize the effectiveness of Eco‐scheme for biodiversity, experts highlighted the need to prioritize evidence‐based actions, allocate a sufficient budget for biodiversity, and incentivize management improvements through higher payment levels. Additionally, stronger coherence is needed among CAP instruments.For effective CAP implementation, the European Commission and the Member States should expand investments in biodiversity monitoring, knowledge transfer, and capacity‐building within relevant institutions. The remaining risks in the CAP's ability to reverse the loss of farmland biodiversity still require better design, closer monitoring, greater transparency, and better engagement with farmers. Additionally, greater involvement of scientists is needed to guide the CAP toward restoring farmland biodiversity while accounting for synergies and trade‐offs with other objectives.

Ocean-atmosphere circulation controls on integrated meteorological and agricultural drought over Iran

Drought may affect more people than any other climate extremes worldwide, especially in (semi)arid climates such as Iran. In this paper, the empirical Multivariate Standardized Drought Index (MSDI) that incorporates the meteorological and agricultural drought conditions is first computed. The wavelet analysis is then used to identify teleconnections between ocean–atmosphere oscillations from Atlantic (AMO, AO, and NAO) and Pacific (ENSO, PDO, and PNA) oceans and Iran’s drought at a highly dense network of regularly gridded points (2485) during 1979–2016. It is found that among the droughts of 1980, 1985–86, 1990–91, 1998–99, 2000, 2007–08, and 2010–11, both the 2007–08 and 2000 are the broadest and strongest across the country. Overall, those droughts that occurred in the 2000–2016 period (average MSDI = -1.14) were, on the whole, stronger than those happened over the latest 20 years of the 20th century (average MSDI = -0.77), reflecting the strengthening of the influence that ENSO has on the Middle East climate in the most recent decades. According to the wavelet coherence results, unlike the Atlantic-based oscillations that almost have an anti-correlation with droughts, there is a positive correlation between Pacific-based oscillations and Iran’s drought. It is also identified that the severe historical droughts across the country were usually associated with a strong La Niña coupled with cold PDO and positive NAO phases in the latest 30 years. Overall, droughts in Iran tend to be substantially controlled by multiple interacting of climate indices since three-coupled indices have stronger coherence with drought than either two-coupled indices or single ones. A combination of the three indices of ENSO, PDO, and NAO has the strongest coherence with Iran’s drought compared to all the other three- and two-coupled, and all single indices, indicating that integrated impact of climate indices can better capture hydroclimate teleconnections. These multiple interacting impacts from the different large-scale climate circulation patterns mark a significant step towards an improved prediction of severe droughts across Iran and can also be used for other parts of the world.

On the Relationship between COVID-19 and G7 Banking Co-Movements

We address G7 banking contagion during the COVID-19 crisis using wavelet-based techniques. We find an increase (20%) of the lowest frequencies banking contagion during the pandemic period based on stronger coherence between all pairs of financial indices. We also find that COVID-19 world cases and deaths are relevant to understand banking cycles co-movements, mainly from February to June. Our findings are confirmed by a correlation contagion test and still hold after controlling for oil prices.

Cultural and Educational Environment in the Global Era: Heuristic Potential for Reaching Integrity

This paper outlines the main referent features of the culture‒education sphere in the framework of globalizing world order, viewed with the help of philosophical concepts, in particular, the heuristic. The relevance of the topic is determined by the problem of the transforming conditions of human life, which influence the formation of his personality as a result of civilizational changes in the globalizing world. The heterogeneity of the cultural space leads humanity to an awareness of the crisis and the search for non-standard solutions. The article sets the objective of revealing the possibilities whereby the education sector can influence the vector of civilizational developments, and of showing new perspectives of such a research. In following this, the study is based on the methodology of systems analysis, and on the interdisciplinary approach which is innovative in a sense that it highlights the heuristic nature of cognitive activity as a wide-format, conceptual solution of the central problem. The theoretical substantiation of the need to maintain the dynamic stability of the cultural and educational environment of Russia exposes the problem of the integrity of the national cultural and educational space. In this respect, the idea brought about is that heuristic can be applied as an analytical tool, balancing the vision on global and national civilizational processes. This can establish a stronger coherence of political and cultural bodies on the both levels mentioned, with heuristic foundation of sustainable development, public administration and governance. The results make it possible to single out a number of program documents of global importance that consolidate the concept of sustainable development as a priority for managing civilizational processes, contributing to the renewal of goal-setting and the formation of a new vision, a new way to treat the reality. The sustainable path that Russia took determines the tools for modeling the integrity of the cultural and educational space, based on the parameters of the balance of material needs, moral values, and ensures coordination of the goals of culture and education.

Alterations of Functional Connectivity During the Resting State and Their Associations With Visual Memory in College Students Who Binge Drink

This study investigated the characteristics of neural oscillation and functional connectivity (FC) in college students engaging in binge drinking (BD) using resting-state electroencephalography (EEG). Also, the associations of visual memory, evaluated by the Rey-Osterrieth Complex Figure Test (RCFT), and neural oscillation with FC during the resting state were investigated. The BD (n = 35) and non-BD (n = 35) groups were selected based on scores of the Korean version of the Alcohol use disorders (AUDs) Identification Test and the Alcohol Use Questionnaire. EEG was performed for 6 min while the participants rested with eyes closed. The theta, lower-alpha, and upper alpha powers did not differ between the BD and non-BD groups. Concerning FC, the BD group exhibited stronger theta coherence than that of the non-BD group, and in the lower and upper alpha bands, the BD group showed stronger coherence in some areas but weaker coherence in others compared with the non-BD group. However, these significant results were not observed after Bonferroni correction. The BD group showed significantly lower delayed recall scores on the RCFT than did the non-BD group. A positive correlation between the left prefrontal-parietal-occipital midline connection and performance on the delayed recall of the RCFT was observed in the BD group. The present results could suggest that binge drinkers have alterations in brain FC, which may be related to their visual memory deficits.

The shifting position of homeowners in flood resilience: From recipients to key‐stakeholders

AbstractThe academic debate on flood risk governance is paying increased attention to the shifting position of homeowners. Homeowners are increasingly expected to adapt their homes to protect against possible floods. Although an overall agreement seems to exist on the involvement of homeowners in flood risk governance, the academic literature is dispersed in its argumentation on why homeowners should be involved. Therefore, this article provides a coherent overview of the transition from flood protection to flood risk management, and subsequently of the arguments that unfold regarding the shifting position of homeowners within this debate. This overview, based on a systematic review of the academic literature, helps to shed light on the changing role of homeowners in flood risk governance and contributes to categorizing the arguments used in current academic reasoning on homeowner involvement in flood risk governance. We use a conceptual distinction between macro‐level and micro‐level arguments, and between individual and collective efforts to structure our results. This conceptual overview illustrates the potential gap in convincing homeowners of the urgency to take action, because the connection between the macro‐level arguments (i.e., climate change and responsibility) and the micro‐level arguments (i.e., minimizing flood damage on privately owned properties) is generally not made. We, therefore, suggest that a stronger coherence in the argumentation would contribute to increase homeowner awareness of their changing responsibilities, which might bring about a future shift toward a new phase in flood risk governance, in which the responsibilities of homeowners are more explicitly acknowledged and integrated into climate adaptation strategies.This article is categorized under: Engineering Water > Planning Water Human Water > Water Governance

Adaptive Crowd Segmentation Based on Coherent Motion Detection

In order to obtain effective crowd relationships for crowd behavior analysis, an adaptive crowd segmentation method based on coherent motion detection is proposed. This method can improve the accuracy of segmentation results and be adaptively applied to various collective scenes that have different distributions at different scales. Firstly, an orientation clustering algorithm and a spatial joint strategy are proposed to preliminarily profile all agents into several partitions with different motion orientations. Then, the Natural Nearest Neighbor algorithm is introduced to construct the adaptive crowd motion networks combining with the profiling results, which can describe the neighborhood relationships of agents with stronger coherence. Finally, the improved Coherent Neighbor Invariance optimized by fusing motion information of neighbors is proposed to segment crowds with coherent motions from the crowd motion networks. The experiment results on videos depicting real-world crowd scenes indicate that the proposed method is effective and adaptive to various scenes.

Security in Movables Revisited: Belgium’s Rethinking of the Article 9 UCC System

Abstract: This paper compares Belgian law pertaining to the granting of security interests in movables to US law on this subject. The Belgian system is currently still in the implementation stage, leaving it less detailed but benefiting from stronger coherence and a fresh start. The US system, set forth in Article 9 of the Uniform Commercial Code (UCC), is much older and highly detailed and, therefore, better equipped to deal with the intricacies of practice, but at the cost of a loss of clarity and second-best solutions largely caused by path dependence. This study tries to identify the areas where one system might learn from the other. As the UCC system was a major source of inspiration for the Belgian reform, leading to the shared basic foundation of a functional approach to security interests, which are to be made publicly knowable by way of register publicity, the systems are ideally suited for a straight comparison. As the basic premises are identical, the focus can be shifted to their implementation. After setting out the boundaries within which security interests operate in terms of assets and debts covered, this paper follows the lifetime of the security interest, from the way they are set up between the parties, to how they are made enforceable against third parties, down to the way they meet their end in a possible bona fide purchase or foreclosure, comparing the two systems every step of the way. Given that the Belgian government is currently designing how the system will actually work and the difficulty of making changes to such a vast system once it is in place, this kind of analysis is of key importance for the future proper functioning of secured lending in Belgium. The lessons taken from this comparative analysis are therefore translated into actionable proposals and best practices for the implementation and application of the Belgian Pledge law. These range from the judicial adoption of similar guidelines on what constitutes a sufficient description of collateral, over the freedom to negotiate default clauses and the limitations to that freedom, to a broad conception of forced dispositions of collateral. This study anticipates judicial interpretation of the new Pledge law in order to provide Belgian practitioners and judges with the necessary tools ahead of time. From the other point of view, it shows those weaknesses of the UCC system that could be remedied through an overhaul of the system.

‘The Danes don't get this’: the economic crash and Icelandic postcolonial engagements

In the early 2000s, Iceland enjoyed an extensive boom period that ended abruptly with an economic crash in 2008. This paper focuses on how Iceland's past as a Danish dependency was revisited in the economic boom period. The Danes were widely seen as the former colonial rulers who were ‘jealous’ of Icelanders’ success, in turn, giving the Icelandic national identity a stronger coherence. The concept ‘colonialism without colonies’ is applied to the Icelandic situation in terms of its potential and limitations, emphasising that a nuanced look at colonialism has to involve the consideration of contradictory desires and subject positions.

Theoretical Study of σ-π Conjugated Semiconductors Based on cis- and trans-Cyclopropane Derivatives

The high strain cyclopropane as σ block model inserted in organic semiconductors to tune the structures and optical properties was investigated by the density functional theory method. The band gaps and absorption peaks of 1,2-disubstituted cyclopropanes were between the corresponding alkanes and olefins. The cis-isomers had higher steric strain between two substituents and lower symmetry than the trans-isomers in ground-state structures. The electronic transitions (S0→S1) were mainly on the aryl parts, which were stronger coherence with surrounding atoms in cis-isomers, while the trans-isomers were on the cyclopropyl. Furthermore, 1,2-disubstituted cyclopropanes (1A, 1B, 2A, 4B) could respond to the charge stimulation, which are potential materials for organic electronics and mechatronics.

Scale and time dependence of serial correlations in word-length time series of written texts

This work considered the quantitative analysis of large written texts. To this end, the text was converted into a time series by taking the sequence of word lengths. The detrended fluctuation analysis (DFA) was used for characterizing long-range serial correlations of the time series. To this end, the DFA was implemented within a rolling window framework for estimating the variations of correlations, quantified in terms of the scaling exponent, strength along the text. Also, a filtering derivative was used to compute the dependence of the scaling exponent relative to the scale. The analysis was applied to three famous English-written literary narrations; namely, Alice in Wonderland (by Lewis Carrol), Dracula (by Bram Stoker) and Sense and Sensibility (by Jane Austen). The results showed that high correlations appear for scales of about 50–200 words, suggesting that at these scales the text contains the stronger coherence. The scaling exponent was not constant along the text, showing important variations with apparent cyclical behavior. An interesting coincidence between the scaling exponent variations and changes in narrative units (e.g., chapters) was found. This suggests that the scaling exponent obtained from the DFA is able to detect changes in narration structure as expressed by the usage of words of different lengths.

Characteristics of scintillations and bit error rate of partially coherent rectangular array beams in turbulence

According to the paraxial form of the extended Huygens–Fresnel principle, the analytical formulas of the on-axis average irradiance and the on-axis scintillation index for a rectangular array Gaussian Schell-model (RAGSM) beams in atmospheric turbulence have been derived. The on-axis bit error rate has been analyzed quantitatively. Their effects of the turbulence intensity, the initial correlation length, and the array parameters including the beamlet number ( M and N) and the array separation distance ( x 0 and y 0) have been discussed. The results show that the correlated and uncorrelated superposition RAGSM beams exhibit the different on-axis intensity distribution, the similar variation of the on-axis scintillation and the bit error rate. At the nearer propagation distance the on-axis scintillation rises against propagation distance with the increasing beamlet number and the decreasing array separation distance, whereas the situation is reversed at the farther propagation distance. The effects of array parameters on the bit error rate are similar to that on the scintillation. For a given propagation distance the scintillation index increases with the stronger coherence and the larger waist width of the array beam.

Anisotropic strain relaxation of thin Fe film on c(4×4) reconstructed GaAs (001) surface

We report the interplay between the anisotropic strain relaxation and the in-plane uniaxial magnetic anisotropy in a 5 nm Fe film grown on GaAs (0 0 1) by molecular-beam epitaxy. Tetragonal distortion and in-plane anisotropic strain relaxation were accurately measured by synchrotron X-ray diffraction. A stronger coherence at the interface between Fe and GaAs is also observed in the annealed film. A competing model including magnetocrystalline anisotropy, interface anisotropy, and magnetoelastic anisotropy is proposed to characterize the in-plane magnetic anisotropy.

Analysis of Convection and Its Association with African Easterly Waves

Abstract The association between convection and African easterly wave (AEW) activity over tropical Africa and the tropical Atlantic during the boreal summer is examined using satellite brightness temperature (TB) and ECMWF reanalysis datasets. Spectral analysis using 18 yr of TB data shows significant variance in the 2–6-day range across most of the region. Within the regions of deep convection, this time scale accounts for about 25%–35% of the total variance. The 2–6-day convective variance has similar amplitudes over western and eastern Africa, while dynamic measures of AEW activity show stronger amplitudes in the west. This study suggests that weak AEW activity in the east is consistent with initial wave development there and indicates that convection triggered on the western side of the mountains over central and eastern Africa, near Darfur (western Sudan) and Ethiopia, has a role in initiating AEWs westward. The subsequent development and growth of AEWs in West Africa is associated with stronger coherence with convection there. Results show large year-to-year variability in convection at the 2–6-day time scale, which tends to vary consistently with the mean convection and dynamical measures of AEW activity over West Africa and the Atlantic, but not over central and eastern Africa. The Darfur region is particularly important for providing convective precursors that propagate westward and trigger AEWs downstream. During wet years, convection over eastern Africa (western Ethiopian highlands) can be a significant source of AEW initiation. In addition to being important for precursors of AEWs, the Darfur region is also a source of convection that propagates eastward toward Ethiopia.

Cortico-cortical coupling patterns during dual task performance.

We investigated the neural correlates of dual task performance using EEG coherence as a measure of the functional coupling between cortical regions. Nine healthy participants performed a rhythmical movement with the right hand and an isometric contraction with the left hand, either initiated simultaneously or successively. EEG data revealed that dual task performance was associated with stronger coherence in left hemispheric and mesial areas than the sum of the tasks performed separately in the beta (>12-30 Hz), but not alpha (8-12 Hz), band. This effect was more pronounced when the two assignments were initiated simultaneously, as opposed to successively. The data demonstrate that the pattern of cortico-cortical coupling during bimanual actions is not just the sum of that associated with its component parts, but is increased according to coordinative demands and processing load.

Planetary-Scale Baroclinic Instability and the MJO

Eastward propagating planetary waves of zonal wavenumber one in the zonal wind (u) with phase speeds in the range of 1–10 m s−1, and also with frequencies in the 30–60-day range, are studied using 39 boreal winter (austral summer) seasons (each of length 180 days) from the reanalyses of the National Centers for Environmental Prediction. The purpose of the paper is to study the relationship between these low phase speed waves in the extratropics (which are candidates for instabilities) and the low-frequency tropical waves associated with the Madden–Julian oscillation (MJO). Planetary waves dominate the zonal wavenumber spectrum of all (eastward plus westward) transient fluctuations with phase speeds of 1–10 m s−1 at upper levels. Using the theory of Y. Hayashi to separate out standing oscillations, it is found that eastward propagating waves for zonal wavenumber one have variance maxima at 63°N, 32°N, 13°N, 32°S, and 52°S at upper levels. As a percentage of the total variance for phase speeds 1–10 m s−1 and zonal wavenumber one, the eastward propagating waves have strong maxima at 200 hPa in the Tropics (13°N, 13°S) and at lower levels at 13°S (indicative of the MJO). The standing wave variance is maximum in northern midlatitudes. The eastward propagating wave variance for zonal wavenumber two has similar properties. For zonal wavenumber one, eastward propagating waves at 52°N and 300 hPa are highly coherent with mid- and upper-level waves at 32°N, with a nearly perfectly out-of-phase relationship. For a base point at 32°N, 200 hPa, we find a strong coherence maximum for phase speeds of 1–10 m s−1 (coherence squared greater than 0.7) with upper levels in the Tropics (13°N), accompanied by a 180° relative phase shift. Coherence and phase plots with a base point at 13°N and 200 hPa show not only strong coherence with waves at 32°N, but also with waves at 13°S at 700 hPa. While results for the MJO averaging (corresponding to periods of 30–60 days) are generally similar, there is in addition a strong cross-equatorial coherence between fluctuations at 13°N and 13°S at 200 hPa, and stronger coherence with the lower tropical troposphere. The strong coherence between waves in the subtropics (32°N) and the Tropics (13°N) indicates a potential role for dynamical instability in the organization of the MJO. Coherence and phase diagnostics for base points in the Southern Hemisphere have generally the same character, although the subtropical–tropical coherence is less dramatic (but still significant). Coherence and phase results for eastward propagating zonal wavenumber two are generally similar. These results represent, for midlatitudes, an extension of earlier work of C. R. Mechoso and D. L. Hartmann to phase speeds less than 10 m s−1, for which an interpretation in terms of baroclinic instability becomes viable;a much larger dataset is also used here. The strong coherence found between the subtropics and Tropics lend support to the notion that planetary wave baroclinic instability and the MJO are connected with each other, as suggested by J. S. Frederiksen and C. S. Frederiksen. An origin of the MJO in which subtropical jet instability helps to organize tropical convection is suggested.