Multi-Zone Active Noise Control Strategy for the Scattered Sound Control of an Infinite Rigid Cylinder

Active noise control can be used to reduce the scattered sound of a reflecting object to make it invisible to incident acoustic waves. For the multi-zone active noise control of scattered sound from an infinite rigid cylinder, an active control strategy is proposed that combines the least absolute shrinkage and selection operator (LASSO) algorithm with constraint points and regularized least squares (RLS) algorithm. The proposed control strategy is used to promote control performance through optimizing the secondary loudspeaker placement of an active noise control system. Compared with the RLS algorithm employing the uniformly placed loudspeakers and the traditional LASSO algorithm, the proposed strategy has better reduction performance both in the forward-scattered and backward-scattered sound target areas, and there is less sound amplification in the far field. From 400 Hz–1100 Hz, the proposed strategy provides a 5 dB–16 dB reduction performance advantage in the target area compared to the RLS algorithm employing uniformly placed loudspeakers.

Control Measures for Continuous Deep Sedation Until Death: A Framing Analysis of the Views of Physicians

Physicians have been subject to increasing external control to improve their medical practice, and scholars have theorized extensively about their opposition to such control. However, little empirical attention has been paid to the views and reasoning that lie behind this opposition. An in-depth understanding is necessary for enhancing the effectiveness and efficiency of external controls, and continuous deep sedation until death (CDS) is an interesting case in this regard. This study aims to explore how physicians frame control measures for CDS. We conducted 47 semi-structured interviews with Belgian physicians in 2019. A qualitative framing analysis was performed to analyze their views and reasoning. This study reveals that physicians approach CDS practice and control measures with different emphases. Controlling by mechanisms of professional self-regulation and state governance are put forward as appropriate means to improve CDS practice. Policymakers should take into consideration physicians’ frames to develop sound control measures.

Increased burrow oxygen levels trigger defensive burrow-sealing behavior by plateau zokors

Defensive behaviors are a response to immediate and potential threats in the environment, including abiotic and biotic threats. Subterranean rodents exhibit morphological and physiological adaptions for life underground, and they will seal with mounds and additional plugs when their burrow opened. However, little is known about the factors driving this defensive behavior. In this study, we selected a subterranean rodent, plateau zokor (Myospalax fontanieri), as a species to investigate (both in the laboratory and in the field) the possible factors responsible for burrow-sealing behavior. Our results showed that: (1) In the laboratory, the burrow-sealing frequency of plateau zokor in response to five factors were as follows: oxygen (52.63%) > light (34.58%) > temperature (20.24%) > gas flow (6.48%) > sound/control (0%). Except for light, the burrow-sealing frequency in response to other factors was significantly lower than that in response to oxygen (P < 0.05). (2) Burrow-sealing behavior in response to each treatment did not differ significantly between males and females in the laboratory experiment. (3) In the field, during the animal’s active periods in both the cold and warm season, the burrow-sealing frequency under the oxygen treatment was higher than that under the light and temperature treatments. Plateau zokors were found not to be sensitive to these treatments during their inactive periods during both the cold and warm season. (4) The latency to reseal the burrow showed no obvious differences between each treatment both in the laboratory and in the field. In conclusion, the main factor that influences the burrow-sealing behavior of plateau zokors is the variation in oxygen concentration, and this defensive behavior is related to their activity rhythm.

Removal of total nitrogen from wastewater by a combination of Chlorella sp. and audible sound

In developing countries, nitrogen in the traditional market wastewater is a critical environmental problem. In this study, the microalga Chlorella sp., which was isolated from wastewater, was used to remove the total nitrogen (TN) from conventional market wastewater in combination with audible sound (Vietnamese classical music). In addition, effects of sound exposure on removal efficiency at different initial cell densities were analyzed. Results revealed that music sound control demonstrates potential to improve the removal efficiency. TN removal efficiencies of 96%, 69.5%, and 4.3% were observed for treatments with Chlorella sp./audible sound, Chlorella sp., and without Chlorella sp., respectively. The significance of probability value (p-value) (&lt;0.05) on the paired sample t-test confirmed the critical role of audible sound and Chlorella sp. density on the TN removal in screening experiments. The predicted optimal conditions for TN removal were as follows: a Chlorella sp. density of 4%, an audible sound of 52.5 dB, and a cultivation time of 4.6 days. Results based on statistical analysis revealed that the quadratic models for TN removal are significant at a low p-value (&lt;0.05) and a high predicted coefficient of determination (R2 = 0.9452) value. The obtained statistical results also indicated that most of the variables are significant for the abatement of TN from market wastewater using Chlorella sp.

The Sound of Laïcité

Sound control policies already had a long history in the French-controlled settlements of the Senegalese coast by the time the prefect of Dakar issued a decree in 1953 prohibiting the use of loudspeakers on public roads and in the open-air courtyards of private residences. Such policies aimed at silencing the nighttime recitation of poems known in the Wolof language of Senegambia as xasida (and referred to by French administrators as chants religieux). Derived from the Arabic term for “ode” (qaṣīda), such poems formed a key component of the liturgy of Senegal's expanding Sufi orders. In this same period, the first Senegalese-owned printing presses began disseminating xasida in printed form more widely than ever, and at times against the wishes of the leadership of the Muridiyya, one of Senegal's leading sufi orders. By highlighting the intertwined nature of print, public recitation, and sound control in midcentury Senegal, this article seeks to illuminate the institutional and political contexts that shaped the production and reception of specific genres of Islamic scholarship in the late colonial period.

Optimization of an absorbing surface with 2D Helmholtz resonators for reduced sensitivity to the incidence angle

It has been shown in several recent publications that acoustic materials consisting of a combination of resonators tuned to different frequencies can render high absorption coefficient values over an extended frequency range while maintaining compactness. This makes them attractive solutions for applications in which low frequency sound control is needed, and/or when there are significant space constraints. Nevertheless, the acoustic performance of these surfaces varies with the angle at which a wave impinges on the surface. The changes in the absorption characteristics with the incidence angle occur both on the maximum absorption coefficient, and on the effective frequency bandwidth. Numerical optimization is a tool that can help realize designs with a large degree of geometrical freedom, and using this framework we have demonstrated an array of coupled 2D Helmholtz resonators that is less sensitive to changes in the incidence angle.

Band structure and defect states in acoustic phononic crystals using expansion and micro-perforated chamber mufflers

The expansion and the micro-perforated chamber mufflers are acoustic silencers designed to attenuate the sound propagation at duct systems. These silencers can show interesting phononic crystals behavior when set periodically. The concept of phononic crystals still is an emerging topic in vibration and sound control. The periodic arrangement of acoustic silencers can provide a significant enhancement of the sound absorption due to the "wave filtering" property where the wave cannot propagate at certain frequency ranges, called stopbands or bandgaps. However, these properties may be affected by defects, like the break of the periodicity due to manufacturing errors. For the present work, the influence of some defects on the acoustic efficiency is investigated numerically for expansion and micro-perforated chamber mufflers. A direct and efficient approach is used to obtain the transfer and dynamic stiffness matrices. Simulated examples are used to calculate the forced response, transmission loss, and dispersion diagram, which are verified by other methods.

Evaluation of Fractalkine and Migration Inhibitory in the Patient with Atherosclerosis

Atherosclerosis (AS) a is the major underlying clinical mechanism of CVD. Cardiovascular diseases (CVD) are the leading cause of death globally, many factors such as MIF, CX3CL1, GSH and MDA were isociated with atherosclerosis. Materials and method: Sixty back to back patients with conclusion of atherosclerosis along with 30 sound control subjects were enlisted. Venous blood tests were gathered not long before the coronary atheterization methodology (in examination patients). MIF, CX3CL1, GSH and MDA fixation was resolved utilizing financially accessible colorimetric kits. Results: The most elevated value of MIF, MDA, FKN in patient group while decline of GSH in serum level patients. (0.482, 0.512 (ng\ml), 7.28 (μmole/L), respectively; p<0.05). Conclusion: The new data MIF, CX3CL1, GSH and MDA demonstrate a significant job for these components being developed of atherosclerosis, simultaneously these elements information were reveals insight into their job in tweak the safe reaction and irritation in the aortic divider.

Probiotic Bacteria with High Alpha-Gal Content Protect Zebrafish against Mycobacteriosis

Mycobacteriosis affects wild fish and aquaculture worldwide, and alternatives to antibiotics are needed for an effective and environmentally sound control of infectious diseases. Probiotics have shown beneficial effects on fish growth, nutrient metabolism, immune responses, disease prevention and control, and gut microbiota with higher water quality. However, the identification and characterization of the molecules and mechanisms associated with probiotics is a challenge that requires investigation. To address this challenge, herein we used the zebrafish model for the study of the efficacy and mechanisms of probiotic interventions against tuberculosis. First, bacteria from fish gut microbiota were identified with high content of the surface glycotope Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal) that has been shown to induce protective immune responses. The results showed that probiotics of selected bacteria with high α-Gal content, namely Aeromonas veronii and Pseudomonas entomophila, were biosafe and effective for the control of Mycobacterium marinum. Protective mechanisms regulating immunity and metabolism activated in response to α-Gal and probiotics with high α-Gal content included modification of gut microbiota composition, B-cell maturation, anti-α-Gal antibodies-mediated control of mycobacteria, induced innate immune responses, beneficial effects on nutrient metabolism and reduced oxidative stress. These results support the potential of probiotics with high -Gal content for the control of fish mycobacteriosis and suggested the possibility of exploring the development of combined probiotic treatments alone and in combination with -Gal for the control of infectious diseases.