Self-Gravitating Phase Transitions: Point Particles, Black Holes and Strings

We compute the quantum string entropy S_s(m,j) of the microscopic string states of mass m and spin j in two physically relevant backgrounds: Kerr (rotating) black holes and de Sitter (dS) space-time. We find a new formula for the quantum gravitational entropy S_{sem} (M, J), as a function of the usual Bekenstein-Hawking entropy S_{sem}^(0)(M, J). We compute the quantum string emission by a black hole in de Sitter space-time (bhdS). In all these cases: (i) strings with the highest spin, and (ii) in dS space-time, (iii) quantum rotating black holes, (iv) quantum dS regime, (v) late bhdS evaporation, we find a new gravitational phase transition with a common distinctive universal feature: A square root branch point singularity in any space-time dimensions. This is the same behavior as for the thermal self-gravitating gas of point particles (de Vega-Sanchez transition), thus describing a new universality class.Comment: Invited lecture at `Statistical Mechanics of Non-Extensive Systems', Observatoire de Paris, 24-25 October 2005, to be published in a Special issue of `Les Comptes rendus de l'Academie des sciences', Elsevie

Zebrafish as animal model for aquaculture nutrition research.

The aquaculture industry continues to promote the diversification of ingredients used in aquafeed in order to achieve a more sustainable aquaculture production system. The evaluation of large numbers of diets in aquaculture species is costly and requires time-consuming trials in some species. In contrast, zebrafish (Danio rerio) can solve these drawbacks as an experimental model, and represents an ideal organism to carry out preliminary evaluation of diets. In addition, zebrafish has a sequenced genome allowing the efficient utilization of new technologies, such as RNA-sequencing and genotyping platforms to study the molecular mechanisms that underlie the organism's response to nutrients. Also, biotechnological tools like transgenic lines with fluorescently labeled neutrophils that allow the evaluation of the immune response in vivo, are readily available in this species. Thus, zebrafish provides an attractive platform for testing many ingredients to select those with the highest potential of success in aquaculture. In this perspective article aspects related to diet evaluation in which zebrafish can make important contributions to nutritional genomics and nutritional immunity are discussed

Utilization of Pyrosequencing to Monitor the Microbiome Dynamics of Probiotic Treated Poultry (Gallus gallus domesticus) during Downstream Poultry Processing

Antibiotic growth promoters that have been historically employed to control pathogens and increase the rate of animal development for human consumption are currently banned in many countries. Probiotics have been proposed as an alternative to control pathogenic bacteria. Traditional culture methods typically used to monitor probiotic effects on pathogens possess significant limitations such as a lack in sensitivity to detect fastidious and non-culturable bacteria, and are both time consuming and costly. Here, we tested next generation pyrosequencing technology as a streamline and economical method to monitor the effects of a probiotic on microbial communities in juvenile poultry (Gallus gallus domesticus) after exposure to several microbiological challenges and litter conditions. Seven days and repeated again at 39 days following hatching, chicks were challenged with either Salmonella enterica serovar Enteritidis, Campylobacter jejuni, or no bacteria in the presence of, or without a probiotic (i.e., Bacillus subtilis) added to the feed. Three days following each of two challenges (i.e., days 10 and 42, respectively) the microbiome distributions of the poultry caecum were characterized based on 16S rDNA analysis. Generated PCR products were analyzed by automated identification of the samples after pooling, multiplexing and sequencing. A bioinformatics pipeline was then employed to identify microbial distributions at the phylum and genus level for the treatments. In conclusion, our results demonstrated that pyrosequencing technology is a rapid, efficient and cost-effective method to monitor the effects of probiotics on the microbiome of poultry propagated in an agricultural setting

The power of play : a theoretical study of play, the self, and the public school

The objective of this theoretical study was to examine how the decrease of play in early childhood education is affecting the developmental process of the child. Noted implications for the lack of play in schools included a decrease in creative thinking and imagination in childhood, an increase in ADHD and depression in children, an increase in preschool expulsions, an increase in special education services, and disparities in access to play for children of color and children living in poverty. A theoretical framework was used to examine the intersection between play, the school environment, and the developing child. The analysis utilized Donald W. Winnicott\u27s theory of object relations and Michel Foucault\u27s theory of disciplinary power to address four central questions regarding this phenomenon: 1) How does the lack of play in school affect the child\u27s sense of self? 2) What environmental factors maintain the decrease of play in early childhood education and how do these factors affect the child? 3) Who is most effected by this phenomenon and why? 4) How can we begin to think of education in a different way in order to value academic learning while remaining sensitive to the child\u27s growing sense of self? Implications for clinical social workers were explored. Finally, this thesis suggests that if we are to create spaces in this world for children to become fully alive, then we must find a way to mitigate our demands for who they should be so that we can allow them to become who they ar

Semiclassical (Quantum Field Theory) and Quantum (String) de Sitter Regimes: New Results

We compute the quantum string entropy S_s(m, H) from the microscopic string density of states rho_s (m,H) of mass m in de Sitter space-time. We find for high m, a {\bf new} phase transition at the critical string temperature T_s= (1/2 pi k_B)L c^2/alpha', higher than the flat space (Hagedorn) temperature t_s. (L = c/H, the Hubble constant H acts at the transition as producing a smaller string constant alpha' and thus, a higher tension). T_s is the precise quantum dual of the semiclassical (QFT Hawking-Gibbons) de Sitter temperature T_sem = hbar c /(2\pi k_B L). We find a new formula for the full de Sitter entropy S_sem (H), as a function of the usual Bekenstein-Hawking entropy S_sem^(0)(H). For L << l_{Planck}, ie. for low H << c/l_Planck, S_{sem}^{(0)}(H) is the leading term, but for high H near c/l_Planck, a new phase transition operates and the whole entropy S_sem (H) is drastically different from the Bekenstein-Hawking entropy S_sem^(0)(H). We compute the string quantum emission cross section by a black hole in de Sitter (or asymptotically de Sitter) space-time (bhdS). For T_sem ~ bhdS << T_s, (early evaporation stage), it shows the QFT Hawking emission with temperature T_sem ~ bhdS, (semiclassical regime). For T_sem ~ bhdS near T_{s}, it exhibits a phase transition into a string de Sitter state of size L_s = l_s^2/L}, l_s= \sqrt{\hbar alpha'/c), and string de Sitter temperature T_s. Instead of featuring a single pole singularity in the temperature (Carlitz transition), it features a square root branch point (de Vega-Sanchez transition). New bounds on the black hole radius r_g emerge in the bhdS string regime: it can become r_g = L_s/2, or it can reach a more quantum value, r_g = 0.365 l_s.Comment: New original materia

Semiclassical (QFT) and Quantum (String) anti - de Sitter Regimes: New Results

We compute the quantum string entropy S_s(m, H) from the microscopic string density of states of mass m in Anti de Sitter space-time. For high m, (high Hm -->c/\alpha'), no phase transition occurs at the Anti de Sitter string temperature T_{s} which is higher than the flat space (Hagedorn) temperature t_{s}. (the Hubble constant H acts as producing a smaller string constant and thus, a higher tension). T_s is the precise quantum dual of the semiclassical (QFT) Anti de Sitter temperature scale . We compute the quantum string emission by a black hole in Anti de Sitter space-time (bhAdS). In the early evaporation stage, it shows the QFT Hawking emission with temperature T_{sem~bhAdS}, (semiclassical regime). For T_{sem~bhAdS}--> T_{s}, it exhibits a phase transition into a Anti de Sitter string state. New string bounds on the black hole emerge in the bhAdS string regime. We find a new formula for the full (quantum regime included) Anti de Sitter entropy S_{sem}, as a function of the usual Bekenstein-Hawking entropy S_{sem}^(0). For low H (semiclassical regime), S_{sem}^(0) is the leading term but for high H (quantum regime), no phase transition operates, in contrast to de Sitter space, and the entropy S_{sem} is very different from the Bekenstein-Hawking term S_{sem}^(0).Comment: Comments 26 pages; no figure

Semiclassical (QFT) and Quantum (String) Rotating Black Holes and their Evaporation: New Results

Combination of both quantum field theory (QFT) and string theory in curved backgrounds in a consistent framework, the string analogue model, allows us to provide a full picture of the Kerr-Newman black hole and its evaporation going beyond the current picture. We compute the quantum emission cross section of strings by a Kerr-Newmann black hole (KNbh). It shows the black hole emission at the Hawking temperature T_{sem} in the early evaporation and the new string emission featuring a Hagedorn transition into a string state of temperature T_ s at the last stages. New bounds on the angular momentum J and charge Q emerge in the quantum string regime. The last state of evaporation of a semiclassical KNbh is a string state of temperature T_s, mass M_s, J = 0 = Q, decaying as a quantum string into all kinds of particles.(There is naturally, no loss of information, (no paradox at all)). We compute the microscopic string entropy S_s(m, j) of mass m and spin mode j. (Besides the usual transition at T_s), we find for high j, (extremal string states) a new phase transition at a temperature T_{sj} higher than T_s. We find a new formula for the Kerr black hole entropy S_{sem}, as a function of the usual Bekenstein-Hawking entropy . For high angular momentum, (extremal J = GM^2/c), a gravitational phase transition operates and the whole entropy S_{sem} is drastically different from the Bekenstein-Hawking entropy. This new extremal black hole transition occurs at a temperature T_{sem J} higher than the Hawking temperature T_{sem}.Comment: New articl

Robot Impedance Control and Passivity Analysis with Inner Torque and Velocity Feedback Loops

Impedance control is a well-established technique to control interaction forces in robotics. However, real implementations of impedance control with an inner loop may suffer from several limitations. Although common practice in designing nested control systems is to maximize the bandwidth of the inner loop to improve tracking performance, it may not be the most suitable approach when a certain range of impedance parameters has to be rendered. In particular, it turns out that the viable range of stable stiffness and damping values can be strongly affected by the bandwidth of the inner control loops (e.g. a torque loop) as well as by the filtering and sampling frequency. This paper provides an extensive analysis on how these aspects influence the stability region of impedance parameters as well as the passivity of the system. This will be supported by both simulations and experimental data. Moreover, a methodology for designing joint impedance controllers based on an inner torque loop and a positive velocity feedback loop will be presented. The goal of the velocity feedback is to increase (given the constraints to preserve stability) the bandwidth of the torque loop without the need of a complex controller.Comment: 14 pages in Control Theory and Technology (2016

Integral mathematical model of power quality disturbances

Power quality (PQ) disturbances lead to severe problems in industries and electrical grids. To mitigate PQ problems, the accurate detection and classification of the possible disturbances are essential. A large number of studies exists in this field. The first research step in these studies is to obtain several distorted signals to test the classification systems. In this regard, the most common trend is the generation of signals from mathematical models. In the literature, we can find several models with significant differences among them. However, to the best of our knowledge, there is no integral model that considers all types of distortions. This work presents an integral mathematical model based on the models found in the literature. The model also includes new types of combined disturbances. Twenty-nine disturbances are considered. Additionally, this work includes a software version of this integral model that is publicly available to be used by any interested researcher. In this way, PQ disturbances can be generated in a fast and automatic way. This software aims to facilitate future studies, supporting researchers in the modelling stage