Rudolph Clausius (1822–1888) and His Concept of Mathematical Physics

Rudolph Clausius is well known as a pioneer of the mechanical theory of heat (1857) and as the creator of the concept of entropy (1865). Oftentimes, he is also called the discoverer of the second law of thermodynamics although some argue that this law was already established by Sadi Carnot in 1824 (while still based on the caloric theory). But beyond any doubt, it was Clausius who gave in 1850 the first mathematically correct formulation of the first law (in its differential form that is still valid today, dQ = dU + pdV) and a particularly stringent exposition of both the necessity and independence of the two laws, indeed a logical masterpiece. This paper focuses on his concept of mathematical physics for the development of theoretical physics, contributions that have changed physics well beyond the field of thermodynamics

New bands of deuterated nitrous acid (DONO) in the near-infrared using FT-IBBCEAS

The first measurements of near-infrared bands of deuterated nitrous acid (DONO) are presented. The measurements were made using Fourier-Transform Incoherent Broad-Band Cavity-Enhanced Absorption Spectroscopy (FT-IBBCEAS) in the 5800–7800 cm$^{-1}$ region. Two bands of trans-DONO centred at 6212.029 and 7692.496 cm$^{-1}$ were observed and assigned to the 2ν$_{1}$+ν$_{3}$ combination and 3ν$_{1}$ overtone vibrations, respectively. Their rotational band structure was satisfactorily reproduced using PGOPHER. For cis-DONO the 3ν$_{1}$ band was observed at ~7302.5 cm$^{-1}$. In addition, new bands centred at 6142.5 cm$^{-1}$ and 7607.6 cm$^{-1}$ were quite confidently assigned to the 2ν$_{1}$+ν$_{3}$ and 3ν$_{1}$ vibrations of deuterated nitric acid, DNO$_{3}$, respectively

Contribution to the study on sound production in clownfishes (Perciformes, Pomacentridae): a multidisciplinary approach

Clownfishes (Amphiprion spp.) are brightly colored fishes that are members of the Pomacentridae family. They are well known for their mutualistic relationship with tropical sea anemones. These fishes live in social groups in which there is a size-based dominance hierarchy. In this structure where sex is socially controlled, agonistic interactions are numerous and serve to maintain size differences between individuals adjacent in rank. Several studies have reported that vocalizations are associated with agonistic interactions but precise data are lacking and further investigations are needed. The nature of the sound-producing mechanisms also remained unresolved, only resting on few assumptions. Thereby, the main aim of the present thesis is (1) to determine the fundamental components of the acoustic communication in clownfishes, and (2) to explain the mechanisms of sound production. In order to achieve these objectives, the research has been divided into three different axes. Firstly, the study of the acoustic behaviors shows that no acoustic signal is associated with reproductive activities in clownfishes. Sound recordings during agonistic interactions indicate that these fishes produce two types of sounds. Aggressive sounds are produced during chases and threat displays while submissive (or head shaking) sounds are emitted in reaction to aggressive acts by dominant. Both types of sounds show size-related intraspecific differences in dominant frequency and pulse duration: smaller individuals produce higher frequency and shorter duration pulses than larger individuals, and inversely. Consequently, these sonic features might be useful cues for individual recognition and maintenance of cohesion within the group. Secondly, the study of the sound-producing mechanism highlights that aggressive sounds are initiated by buccal jaw teeth snapping caused by rapid mouth closure attributed to a sonic ligament. It appears that the swimbladder does not function as a resonator that amplifies and changes the quality of sounds. This structure is a highly damped sound source prevented from prolonged resonant vibrations. On the other hand, the rib cage might be the major acoustic radiator and its resonant properties might explain the size-related variations observed in pulse duration and dominant frequency. Thirdly, the comparison of aggressive sounds among fourteen clownfish species indicates that the same relationship between fish size and both dominant frequency and pulse duration is spread over the entire group (i.e. tribe Amphiprionini). These results highlight all species use a highly conservative mechanism of vocalization. Pulse period appears to be the most variable acoustic feature and could be involved in species-specific recognition, as well as pulse duration and dominant frequency in a lesser extent through their relationship with body size. Although sound production appears to be restricted to some agonistic behaviors, these sounds seem to constitute an integral part of the peculiar way of life of clownfishes. The aggressive and submissive sounds would also result from two different mechanisms.  Les poissons clowns (Amphiprion spp.), bien connus pour leur relation de mutualisme avec les anémones de mer, font partie de la famille des Pomacentridae. Ces poissons vivent en groupes hiérarchisés sur la base de la taille. Dans cette structure sociale impliquant le respect de la hiérarchie et de la territorialité, les interactions agonistiques sont nombreuses et ont pour but de maintenir des différences de tailles entre les individus de rang adjacent. Plusieurs études ont indiqué la présence de sons au cours des interactions agonistiques mais celles-ci souffrent d’un manque de caractérisation et des investigations plus poussées s’avèrent nécessaires. Seules quelques hypothèses du mécanisme producteur de sons ont été formulées, mais jamais vérifiées. Ainsi, la présente thèse vise à (1) étudier les composantes fondamentales de la communication acoustique chez les poissons clowns, et (2) comprendre les mécanismes de production de sons. Afin de répondre à ces objectifs, la recherche a été divisée en trois volets principaux. Premièrement, l’étude des comportements acoustiques montre qu’aucun son n’est associé aux différentes activités liées à la reproduction chez les poissons clowns. Les enregistrements au cours des interactions agonistiques indiquent que ces poissons produisent deux types de sons. Les sons d’agression sont émis durant les poursuites et autres comportements de menace alors que les sons de soumission sont produits en réponse à une agression de la part d’un dominant. Ces deux types de sons montrent des variations intraspécifiques liées à la taille : les petits individus produisent des pulsations de courtes durées associées à des fréquences élevées, et inversement. Par conséquent, ces caractéristiques acoustiques pourraient être des signaux utiles dans la reconnaissance de l’individu et le maintien de la cohésion au sein du groupe. Deuxièmement, l’étude du mécanisme de production des sons d’agression montre qu’ils résultent du claquement des dents portées par les mâchoires buccales suite à la fermeture rapide de la bouche produite par l’action d’un ligament sonique. Il apparaît que la vessie natatoire ne fonctionne pas comme un résonateur qui amplifie et change la qualité des sons. Cette structure est une source sonore hautement amortie et dépourvue de vibrations prolongées. En revanche, la cage thoracique pourrait être le principal radiateur acoustique et ses propriétés résonantes pourraient expliquer les variations liées à la taille observées dans la durée et la fréquence des pulsations. Troisièmement, la comparaison des sons d’agression entre 14 espèces de poissons clowns indique que la même relation entre la taille du poisson et la fréquence dominante ainsi qu’entre la taille et la durée des pulsations s’applique à l’ensemble du groupe (i.e. la tribu des Amphiprionini). Ces résultats révèlent que les espèces utilisent toutes un mécanisme très conservé. La période des pulsations semble être la caractéristique acoustique majeure pour l’identification des espèces. La durée des pulsations et la fréquence dominante seraient également impliquées en raison de leurs variations liées à la taille. Bien que la production de sons ne soit associée qu’à quelques comportements agonistiques, les sons semblent être indispensable au mode de vie particulier des poissons clowns. En outre, ces sons d’agression et de soumission résulteraient de deux mécanismes différents

Initial studies on the regulation and function of TMEM63C in human kidney cells

Die chronische Niereninsuffizienz hat in unserer heutigen Bevölkerung eine hohe klinische Relevanz. Sie zeichnet sich durch eine irreversible Funktionseinschränkung der Niere aus und ist häufig mit einer Funktionsstörung des glomerulären Filterapparates assoziiert. Einen wichtigen Bestand teil dieses Filters stellen die Podozyten dar, zwischen deren Fußfortsätzen sich eine Schlitzmemb ran befindet, durch welche die selektive Filterung der Moleküle im Blut ermöglicht wird. Neuere Studien deuten darauf hin, dass das transmembrane Protein (TMEM) 63C möglicherweise eine pathophysiologisch relevante Rolle in der Funktion der glomerulären Filtrationsbarriere und somit in der Entstehung der Albuminurie spielen könnte. TMEM63C ist ein Protein, dessen Regulation und funktionelle Bedeutung bislang noch nahezu unbekannt sind. Daher wurde in unseren Studien die Regulation der TMEM63C-Expression auf transkriptioneller und post-transkriptioneller Ebene in humanen Nierenzellen untersucht und erste Versuche bezüglich möglicher Funktionen von TMEM63C in vitro durchgeführt. In unseren Untersuchungen wurde gezeigt, dass die Expression von TMEM63C post-transkriptionell von der micro-RNA 564 reguliert wird. Zudem konnten wir nachweisen, dass die Expression von TMEM63C durch einflussreiche Mediatoren beeinflusst wird, welche eine tragende Rolle in inflammatorischen und fibrotischen Prozessen einnehmen. So kam es zu einem signifikanten Anstieg von TMEM63C unter der Stimulation humaner Nierenzel len mit dem proinflammatorischen Mediator Angiotensin II sowie dem profibrotischen Zytokin transforming growth factor beta. Darüber hinaus wurde gezeigt, dass die Expression von TMEM63C durch den Transkriptionsfaktor nuclear factor 'kappa-light-chain-enhancer' of acti vated B cells reguliert wird. Des Weiteren führten wir Untersuchungen zu möglichen Funktionen von TMEM63C in humanen Nierenzellen durch. Erste Versuche in human embryonic kidney 293- Zellen lassen vermuten, dass TMEM63C in dem Prozess der epithelial-mesenchymalen Transition über die Veränderung des Verhältnisses von alpha-smooth muscle actin zu E-Cadherin involviert sein könnte. Zudem konnten wir einen Einfluss von TMEM63C auf die Expression essenzieller Proteine der Funktion und des Überlebens von Podozyten wie Nephrin oder Proteinkinase B nach weisen. Abschließend führten wir Untersuchungen zum Einfluss von TMEM63C auf die Zellvia bilität und Apoptose durch. In unseren Versuchen ging eine Reduktion von TMEM63C mit einer erhöhten Apoptoserate und einem verminderten Zellüberleben bei humanen Podozyten einher. Dieser Effekt ließ sich auch unter Angiotensin II-Stimulation reproduzieren. Somit unterstützen unsere Ergebnisse die Befunde vorheriger Studien, welche darauf hindeuten, dass TMEM63C eine wichtige Bedeutung für den Erhalt der glomerulären Filtrationsbarriere und der Nierenfunktion besitzen könnte.Chronic kidney disease has a high clinical relevance for our population today. It is characterized by an irreversible functional impairment of the kidney in which impairment of glomerular filtration is a significant and early clinical sign. Podocytes are an important component of the glome-rular filter. A slit membrane locates between the foot processes of podocytes and enables the selective filtering of molecules in the blood. Podocyte damage results in dysfunction of the glomerular fil tration barrier and albuminuria. Recent studies suggest that the transmembrane Protein (TMEM) 63C may play a relevant role in the function of the glomerular filtration barrier and thus in the development of albuminuria. TMEM63C is a protein whose regulation and functional importance is only poorly characterized so far. Consequently, our studies investigated the regulation of TMEM63C expression on transcriptional and post-transcriptional level in human kidney cells and provided first experiments on the possible functions of TMEM63C in vitro. In our studies we demonstrated that the expression of TMEM63C is regulated post-transcriptionally by micro-RNA 564. Furthermore, we showed that the expression of TMEM63C is influenced by mediators that play a major role in inflammatory and fibrotic processes. Thus, a significant increase of TMEM63C was observed by stimulation of human kidney cells with the proinflammatory media tor angiotensin II or the profibrotic cytokine transforming growth factor beta. Furthermore, TMEM63C expression was shown to be regulated by the transcription factor nuclear factor 'kappa light-chain-enhancer' of activated B cells. In addition, we performed investigations on possible functions of TMEM63C in human kidney cells. First experiments in human embryonic kidney 293 cells suggest that TMEM63C might be involved in the process of epithelial-mesenchymal transi tion via the change of the ratio of alpha-smooth muscle actin to E-cadherin. Furthermore, we showed an influence of TMEM63C on the expression of essential proteins of podocyte function and survival, such as nephrin or protein kinase B in podocytes. Finally, we analyzed the influence of TMEM63C on cell viability and apoptosis. In our experiments a reduction of TMEM63C was associated with an increased rate of apoptosis and decreased cell survival in human podocytes in resting as well as in Ang II-stimulated cells. Taken together, our results support the findings of previous studies suggesting that TMEM63C may play an important role in maintaining glomerular barrier and renal function

Experimental observation of the ν2_{2}+4ν3_{3} bands of HD16^{16}O and HD18^{18}O between 14975 and 15275 cm−1^{-1}

The ν$_{2}$+4ν$_{3}$ combination bands of HD$^{16}$O and HD$^{18}$O were measured using Fourier transform-incoherent broadband cavity-enhanced absorption spectroscopy (FT-IBBCEAS) with a spectral resolution of 0.08 cm$^{-1}$. The ro-vibrational lines of these bands were assigned through comparison with ab-initio molecular lines from the Tomsk variational calculation database (http://spectra.iao.ru/). For HD$^{18}$O and HD$^{16}$O in total 114 and 141 strong lines were assigned in the region between 14975.3 cm$^{-1}$ and 15243.3 cm$^{-1}$ and between 14998.5 cm$^{-1}$ and 15274.7 cm$^{-1}$, respectively. While the very satisfactory agreement of line intensities was used for line assignments, a systematic average discrepancy of ~0.305 cm$^{-1}$ in line positions was identified between the measured lines of HD$^{18}$O and the theoretically predicted lines from the Tomsk database. Similarly for HD$^{16}$O, an approximate wavenumber difference of ~0.361 cm$^{-1}$ was observed. The wavenumber accuracy of the Fourier transform cavity enhanced absorption spectrometer was confirmed on basis of concurrently measured H$_{2}$$^{16}$O spectra in the region between 15254.2 cm$^{-1}$ and 15376.9 cm$^{-1}$ and corroborated the systematic shifts of the ab initio data. A few lines of the ν$_{1}$+4ν$_{2}$+2ν$_{3}$ bands of HD$^{16}$O and HD$^{18}$O were also identified. The data are compared and discussed on basis of existing literature data

Technical Note: Trend estimation from irregularly sampled, correlated data

Estimation of a trend of an atmospheric state variable is often performed by fitting a linear regression line to a set of data of this variable sampled at different times. Often these data are irregularly sampled in space and time and clustered in a sense that 5 error correlations among data points cause a similar error of data points sampled at similar times. Since this can affect the estimated trend, we suggest to take the full error covariance matrix of the data into account. Superimposed periodic variations can be jointly fitted in a straight forward manner, even if the shape of the periodic function is not known. Global data sets, particularly satellite data, can form the basis to estimate 10 the error correlations

Auditory evoked potential audiograms in post-settlement stage individuals of coral reef fishes

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