52 research outputs found
Transition from Weak Wave Turbulence to Soliton-Gas
We report an experimental investigation of the effect of finite depth on the
statistical properties of wave turbulence at the surface of water in the
gravity-capillary range. We tune the wave dispersion and the level of
nonlinearity by modifying the depth of water and the forcing respectively. We
use space-time resolved profilometry to reconstruct the deformed surface of
water. When decreasing the water depth, we observe a drastic transition between
weak turbulence at the weakest forcing and a solitonic regime at stronger
forcing. We characterize the transition between both states by studying their
Fourier Spectra. We also study the efficiency of energy transfer in the weak
turbulence regime. We report a loss of efficiency of angular transfer as the
dispersion of the wave is reduced until the system bifurcates into the
solitonic regime.Comment: published in Physical Review Fluid
Confinement effects on gravity-capillary wave turbulence
The statistical properties of a large number of weakly nonlinear waves can be
described in the framework of the Weak Turbulence Theory. The theory is based
on the hypothesis of an asymptotically large system. In experiments, the
systems have a finite size and the predictions of the theory may not apply
because of the presence of discrete modes rather than a continuum of free
waves. Our study focusses on the case of waves at the surface of water at
scales close to the gravity-capillarity crossover (of order 1~cm). Wave
turbulence has peculiar properties in this regime because 1D resonant
interactions can occur as shown by Aubourg \& Mordant. Here we investigate the
influence of the confinement on the properties of wave turbulence by reducing
gradually the size of our wave tank along one of its axis, the size in the
other direction being unchanged. We use space-time resolved profilometry to
reconstruct the deformed surface of water. We observe an original regime of
coexistence of weak wave turbulence along the length of the vessel and discrete
turbulence in the confined direction.Comment: accepted for publication in Physical Review Fluid
Théorie et poétique du hasard : entre l’éphémère et l’éternel dans La valse aux adieux, L’Insoutenable Légèreté de l’être, L’immortalité de Milan Kundera
Intertextuality as a Reflection of Thematic Concerns in Ghada Samman’s Beirut Nightmares
Abstract: This article sheds light on role of intertextuality in reflecting some of the major thematic concerns in Ghada Samman’s Beirut Nightmares. Through a matrix of different texts, she attempts to convey the honorific experience of her narrator during the Lebanese Civil War. Samman exposes the impact of civil war on the daily life and the psychology of her major character. Thus, intertextuality serves as an important thematic tool that contributes in providing a nuanced understanding of the narrator’s tragic experience. Samman weaves myths and literary texts in her narrative in order to comment on the devastating situation resulted from this internal conflict. She highlights the dialogical relationship between her work and previous ones to locate the narrator’s experience within a broader historical and literary context. In this study, Beirut Nightmares is understood through its dependency on prior works to explore themes of confinement, fear, issues of artistic creativity and destruction. Samman’s use of a web of texts enables her to evoke similar feelings within a different socio-cultural context. Accordingly, intertextuality contributes in creating different levels of understanding regarding the narrator’s suffering.
Keywords: Intertextuality, Beirut Nightmares, Ghada Samman, Civil War
The Effect of Automatic Speech Recognition Technologies on Students’ Pronunciation A Case Study of First-year EFL Learners at Biskra University
Epidemiological and Clinical Analysis of Intentional Injuries: A Comprehensive Study in Laghouat Province, Algeria
Introduction:Traumas resulting from intentional assaults, termed as intentional injuries (II), pose a significant challenge to public health. Addressing this challenge requires a meticulous approach from healthcare professionals to provide essential psychological support during evidence collection. This study aims to investigate the correlation between the severity of intentional injuries and variables such as gender, age, and occupation of the affected individuals.Materials and Methods:This research takes the form of a prospective monocentric cross-sectional study conducted over a six-month period, from September 2022 to March 2023. The study was carried out at the forensic medicine department of Ahmed Benadjaila Hospital and at the medical-surgical emergency department of the Laghouat Mixed HospitalResults:The primary objective was to assess the existence of a causal relationship between the severity of intentional injuries and factors such as gender, age, and occupation. The results indicate that 89% of the sampled patients were assaulted by male individuals. The mean age of the patients was 29.89 years, with a range from 4 to 73 years, and a majority of individuals were without a profession (46% of the population). Inferential analysis revealed that gender was a significant risk factor in the severity of intentional injuries, while neither age nor occupation were identified as risk factors in this study.Conclusion:Intentional injuries pose a major public health concern with potentially severe consequences for victims. It is imperative to continue in-depth investigations and studies to develop tailored preventive and safety measures. These findings underscore the importance of devising targeted strategies to mitigate the impact of intentional injuries, highlighting the necessity of a multidisciplinary approach to address this issue comprehensively
Impact of dissipation on the energy spectrum of experimental turbulence of gravity surface waves
We discuss the impact of dissipation on the development of the energy
spectrum in wave turbulence of gravity surface waves with emphasis on the
effect of surface contamination. We performed experiments in the Coriolis
facility which is a 13-m diameter wave tank. We took care of cleaning surface
contamination as well as possible considering that the surface of water exceeds
100~m. We observe that for the cleanest condition the frequency energy
spectrum shows a power law decay extending up to the gravity capillary
crossover (14 Hz) with a spectral exponent that is increasing with the forcing
strength and decaying with surface contamination. Although slightly higher than
reported previously in the literature, the exponent for the cleanest water
remains significantly below the prediction from the Weak Turbulence Theory. By
discussing length and time scales, we show that weak turbulence cannot be
expected at frequencies above 3 Hz. We observe with a stereoscopic
reconstruction technique that the increase with the forcing strength of energy
spectrum beyond 3~Hz is mostly due to the formation and strenghtening of bound
waves.Comment: accepted for publication in Physical Review Fluid
Ionic, not the osmotic component, is responsible for the salinity-induced inhibition of greening in etiolated wheat (Triticum aestivum L. cv. Mv Béres) leaves : a comparative study
Main conclusion Greening was partially (in 300 mM NaCl, , 600 mM or KCl) or fully inhibited (in 600 mM NaCl, or NaCl:KCl) by the ionic and not the osmotic component of salinity. Abstract Although high soil salinity is an increasing global problem, not much is known about how direct exposure to salinity affects etiolated leaves of seedlings germinating in the soil and then reaching the surface. We investigated the effect of various salt treatments on the greening process of leaves in 8- to 11-day-old etiolated wheat (Triticum aestivum L. Mv. Béres) seedlings. Etiolated leaf segments pre-treated on different salt (600 mM NaCl:KCl 1:1, 600 mM NaCl, 600 mM KCl, 600 mM , 600 mM KNO3, 300 mM KCl, 300 mM NaCl or 300 mM ) or isosmotic polyethylene glycol 6000 (PEG) solutions for 1.5 h in the dark and then greened for 16 h on the same solutions were studied. Leaf segments greened on PEG (osmotic stress) or on 300 mM KCl had similar chloroplasts compared to control samples greened on Hoagland solution. Slightly slower development of chloroplast structure and function (photosynthetic activity) was observed in segments greened on 300 mM NaCl or , 600 mM KNO3 or KCl. However, etioplast-to-chloroplast transformation and chlorophyll accumulation were fully inhibited and peculiar prothylakoid swelling occurred in segments greened on 600 mM NaCl, or NaCl:KCl (1:1) solutions. The data indicate that not the high osmolarity of the used salt solution, but its ions, especially , had the strongest negative impact on these processes
STUDY OF PHYSICOCHEMICAL AND MICROBIOLOGICAL QUALITY OF THE SPRING WATERS OF THE REGION OF OUM TEBOUL WILAYA OF EL TARF- ALGERIA
The present work aims to assess the physico-chemical and microbiological parameters of the waters of the three sources (Ain Bergougaya, Ain Sigleb and Siporex) in the region of Oum el Teboul wilaya of El Tarf. Parameters such as temperature, pH, conductivity and salinity were measured in situ with a field multimeter. Hardness (62 mg/L to 266 mg/L), salinity (0.01 to 1 mg/L). From a microbiological point of view, there has been no evidence of the complete absence of germs of contamination such as total coliforms and fecal coliforms. This study compared to the drinking water standards shows that the waters in the area studied are of good quality
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