Dark solitons, modulation instability and breathers in a chain of weakly non-linear oscillators with cyclic symmetry

In the aerospace industry the trend for light-weight structures and the resulting complex dynamic behaviours currently challenge vibration engineers. In many cases, these light-weight structures deviate from linear behaviour, and complex nonlinear phenomena can be expected. We consider a cyclically symmetric system of coupled weakly nonlinear undamped oscillators that could be considered a minimal model for different cyclic and symmetric aerospace structures experiencing large deformations. The focus is on localised vibrations that arise from wave envelope modulation of travelling waves. For the defocussing parameter range of the approximative nonlinear evolution equation, we show the possible existence of dark solitons and discuss their characteristics. For the focussing parameter range, we characterise modulation instability and illustrate corresponding nonlinear breather dynamics. Furthermore, we show that for stronger nonlinearity or randomness in initial conditions, transient breather-type dynamics and decay into bright solitons appear. The findings suggest that significant vibration localisation may arise due to mechanisms of nonlinear modulation dynamics

Single observable concurrence measurement without simultaneous copies

We present a protocol that allows us to obtain the concurrence of any two qubit pure state by performing a minimal and optimal tomography of one of the subsystems through measuring a single observable of an ancillary four dimensional qudit. An implementation for a system of trapped ions is also proposed, which can be achieved with present day experimental techniques.Comment: 4 pages, 1 figur

Relationships and events: towards a general theory of reification and truthmaking.

We propose a novel ontological analysis of relations and relationships based on a re-visitation of a classic problem in the practice of knowledge repre- sentation and conceptual modeling, namely relationship reification. Our idea is that a relation holds in virtue of a relationship's existence. Relationships are therefore truthmakers of relations. In this paper we present a general theory or reification and truthmaking, and discuss the interplay between events and rela- tionships, suggesting that relationships are the focus of events, which emerge from the context (the scene) they occur in

Características reprodutivas de ovelhas Santa Inês cruzadas com reprodutores Dorper e Somalis brasileira.

Os cruzamentos na ovinocultura tornaram-se um importante instrumento para aumentar a velocidade de crescimento dos animais e incrementar os parâmetros reprodutivo, sendo justificadas as pesquisas que gere tecnologias. Objetivou-se, com o presente trabalho, comparar a prolificidade e a fertilidade, de ovelhas Santa Inês (SI) cruzados com as raças Dorper (DP) e Somalis Brasileira (SB). A pesquisa foi conduzida no Campo Experimental Pedro Arle, da Embrapa Tabuleiros Costeiros/SE. Foram utilizadas 95 ovelhas da raça SI com idade variando de dois a sete anos e peso médio de 45,3 kg, criadas em regime semi-intensivo. As fêmeas foram inseminadas por laparoscopia (IL) com sêmen congelado de dois reprodutores das raças DP, SB e SI, formando assim três grupos genéticos: GG1 : SI x SI, GG2 : DP x SI e GG3 : SB x SI. Observou-se que não houve associação entre taxa de fertilidade ao parto e o tipo de acasalamento, obtendo-se taxa média de 43,16 %. A prolificidade média foi de 1,19, não apresentando diferença significativa (P>0,05) entre grupos genéticos. Com base nos resultados, conclui-se que as ovelhas SI apresentaram razoável taxa de fertilidade ao parto, quando submetidas à Inseminação Artificial Laparoscópica em nível de campo, com indução do estro apenas pelo efeito macho; o efeito da heterose sobre a prolificidade pode ser desprezível. Reproductive characteristics of sheep Santa Inês crossed with reproducers Dorper and Somalis Brasileira. Abstract - Interbreedings from the sheep raising become an important means to increase the rapidity of animals growth and even increase reproductive parameters, the searches have been justified for the technological. Advanced development the actual performance considered to confer the prolification and the fertility sheep Santa Snês breed (SI) interbred with the Dorper (DP) and Somalis Brazilian breeds (SB). The search was conduced at experimental rural rustic camp denominated Pedro Arle, to belong to Embrapa Tabuleiros Costeiros/SE. It were utilized ninety five sheeps of the SI breed with age between from two to seven ages and 45,3 medium weight, they were breeding in a half-active regime. The females were inseminated by laparoscopia ( IL) with frozen semen that belongs reproducers of the DP, SB and SI breeds, producing in this manner three genetical groups: GG1: SI x SI, GG2: DP x SI and GG3: SB x SI. So it was understood that there wasn´t any association between the fertility parturition rate in comparison to mating type, obtaining consequently a medium rate of 43,16 %. The prolification average was 1,19, it didn´t present any significative diference ( p>0,05) among to geneticals groups. Basing at these results, it has been concluded that the SI sheeps showed reasonable fertlility rate for the artificial insemination laparoscopic in search level, with induction oestrum only by effect male animal; contrasting the heterose effect and prolification can be worthless

Electronic neuron within a ganglion of a leech (Hirudo medicinalis)

Fil:Aliaga, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Busca, N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Salles, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Collective dipole effects in ionic transport under electric fields

In the context of ionic transport in solids, the variation of a migration barrier height under electric fields is traditionally assumed to be equal to the classical electric work of a point charge that carries the transport charge. However, how reliable is this phenomenological model and how does it fare with respect to Modern Theory of Polarization? In this work, we show that such a classical picture does not hold in general as collective dipole effects may be critical. Such effects are unraveled by an appropriate polarization decomposition and by an expression that we derive, which defines the equivalent polarization-work charge. The equivalent polarization-work charge is not equal neither to the transported charge, nor to the Born effective charge of the migrating atom alone, but it is defined by the total polarization change at the transition state. Our findings are illustrated by oxygen charged defects in MgO and in SiO2

Specific plasmid patterns and high rates of bacterial co-occurrence within the coral holobiont

Despite the importance of coral microbiomes for holobiont persistence, the interactions among these arenot well understood. In particular, knowledge of the co-occurrence and taxonomic importance of specific members of the microbial core, as well as patterns of specific mobile genetic elements (MGEs), is lacking. We used seawater and mucus samples collected from Mussismilia hispida colonies on two reefs located in Bahia, Brazil, to disentangle their associated bacterial communities, intertaxa correlations, and plasmid patterns. Proxies for two broad-host-range (BHR) plasmid groups, IncP-1 and PromA, were screened. Both groups were significantly (up to 252 and 100%, respectively) more abundant in coral mucus than in seawater. Notably, the PromA plasmid group was detected only in coral mucus samples. The core bacteriome of M.hispidamucus was composed primarily of members of the Proteobacteria, followed by those of Firmicutes. Significant host specificity and co-occurrences among different groups of the dominant phyla (e.g., Bacillaceae and Pseudoalteromonadaceae and the genera Pseudomonas, Bacillus, and Vibrio) were detected. These relationships were observed for both the most abundant phyla and the bacteriome core, in which most of the operational taxonomic units showed intertaxa correlations. The observed evidence of host-specific bacteriome and co-occurrence (and potential symbioses or niche space co-dominance) among the most dominant members indicates a taxonomic selection of members of the stable bacterial community. In parallel, host-specific plasmid patterns could also be, independently, related to the assembly of members of the coral microbiome

Estratégias de evocação lexical com critério semântico em adultos após acidente vascular cerebral no hemisfério direito / Semantic verbal fluency strategies in patients after a right-hemisphere stroke

Semantic verbal fluency tasks (SVF) evaluate the ability to generate words from a given criterion in a specified time; these tasks allow for the investigation of language, memory and executive functions. This study aimed to investigate the performance of right hemisphere (RH) post stroke adults in an SVF task. Eleven adults with RH lesion and eleven healthy adults, matched by sex, education and age, were investigated. The participants completed an SVF task (clothes names); the total number of words, clustering and switching variables, and the conformation of semantic networks were measured through computational analysis. We found significant statistical differences in the total number of words (Z score). Topographic analysis of graphs showed a tendency toward smaller semantic networks in the RH lesion group compared with controls. Case series analyzes showed four individuals with deficits in the total number of words and in switching. These participants had predominantly frontal lobe and subcortical lesions, which indicates the interference of lesion-specific locations in the use of SVF strategies. The qualitative analyses presented are groundbreaking for the Brazilian context. We also note the importance of using comparisons between groups and case series analyzes in cognitive neuropsychology investigations

Biodegradação do bagaço de cana-de-açúcar por microrganismos ruminais de caprinos e ovinos.

Resumo: No presente estudo objetivou-se avaliar a degradação do bagaço de cana-de-açúcar (BCA) integral (BIN) ou hidrolisado (BH) pela microbiota ruminal de caprinos e ovinos de raças naturalizadas do Nordeste brasileiro e o potencial desses animais como fontes de microrganismos e/ou enzimas celulolíticas para degradação da fibra do BCA. Para hidrólise do BCA foi utilizada uma solução de NaOH a 50%, 30% na matéria seca (MS). Foram determinadas as concentrações de MS, proteína bruta (PB), cinzas (CZ), fibra detergente neutro (FDN), fibra detergente ácido (FDA), celulose (Cel), hemicelulose (Hcel) e lignina (Lig). A degradação in situ da FDN foi determinada pela incubação ruminal em sacos de náilon do BH nos tempos: 0, 6, 24 e 96 horas. A técnica de duas etapas preconizada por Tilley e Terry foi utilizada para determinar a digestibilidade in vitro da MS (DIVMS). Foi coletado conteúdo ruminal dos animais quatro horas após a infusão de 100g de BIN via fístula ruminal para a separação de microrganismos associados às fases líquida e sólida, utilizando tampão fosfato de sódio 50 mM, pH 6,9. A fração sólida foi submetida ao cultivo in vitro com o substrato BIN, por 96 horas, para determinação da taxa de degradação da MS, FDN e atividade celulolítica. O pH foi determinado nos tempos de cultivo de 24, 48 e 96 horas. O pré-tratamento com NaOH aumentou a DIVMS (P0,05). A inclusão de NaOH aumentou a degradação in situ da FDN, apresentando os ovinos menor tempo de colonização (TC). Houve solubilização da Hcel, da Cel e da Lign no BCA pré-tratado com NaOH. A atividade celulolítica se concentrou na fração sólida independente da espécie doadora do inóculo, sendo observado crescimento microbiano no cultivo in vitro do BIN à partir dessa fração. O pH aumentou com o tempo de cultivo in vitro. Microrganismos ruminais de Caprinos e ovinos naturalizados do Nordeste brasileiro colonizaram e degradaram o BIN e BH. O NaOH pode ser utilizado no pré-tratamento alcalino do BCA. [Biodegradation of sugarcane bagasse by ruminal microorganisms from sheep and goats]. Abstract: The purpose of this study was to evaluate the biodegradation of sugar cane bagasse (SCB), whole (WB) or hydrolyzed (HB) by ruminal microorganisms from Brazilian naturalized goat and sheep breeds, and the animals? potential as a source of microorganisms and/or cellulolytic enzymes for the biodegradation of SCB fiber. SCB hydrolysis was performed using 50% sodium hydroxide solution on 30% of dry matter (DM). The concentrations of DM, crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (Cel), hemicellulose (Hcel) and lignin (Lig) were determined in the WB and HB. For the in situ biodegradation of NDF, the HB was placed in nylon bags and incubated in rumen for 0, 6, 24 and 96 hours. The two-step technique recommended by Tilley and Terry was used to determine the in vitro digestibility of DM (IVDDM). Four hours after infusion of WB (100 g) through the ruminal fistula, the rumen content was collected from the animals and the microorganisms associated with the liquid and solid phases were separated, the former by filtration and the latter by extraction with 50 mM sodium phosphate buffer, pH 6.9. The solid fraction was subjected to in vitro culture with WB substrate for 96 hours to determine the biodegradation rate of DM, NDF and cellulolytic activity. The pH was measured after culture times of 24, 48 and 96 hours. Pretreatment with NaOH increased the IVDDM (P 0.05). The addition of NaOH increased the in situ biodegradation rate of NDF, with sheep showing a lower lag time (LT). There was a solubilization of Hcel, Cel and Lig in SCB pretreated with NaOH. Cellulolytic activity was higher in the solid phase, irrespective of the inoculum source, and microbial growth was observed in in vitro cultures using microorganisms from the solid phase and WB as substrate. The pH of the in vitro culture increased over time. Ruminal microorganisms from Brazilian naturalized goat and sheep breeds successfully colonized and biodegraded both WB and HB. Sodium hydroxide proved useful as an alkaline pretreatment for SCB