Under-the-cell routing to improve manufacturability

The progressive miniaturization of technology and the unequal scalability of the BEOL and FEOL layers aggravate the routing congestion problem and have a negative impact on manufacturability. Standard cells are designed in a way that they can be treated as black boxes during physical design. However, this abstraction often prevents an efficient use of its internal free resources. This paper proposes an effective approach for using internal routing resources without sacrificing modularity. By using cell generation tools for regular layouts, libraries are enriched with cell instances that have lateral pins and allow under-the-cell connections between adjacent cells, thus reducing pin count, via count and routing congestion. An approach to generate cells with regular layouts and lateral pins is proposed. Additionally, algorithms to maximize the impact of under-the-cell routing are presented. The proposed techniques are integrated in an industrial design flow. Experimental results show a significant reduction of design rule check violations with negligible impact on timing.Peer ReviewedPostprint (author's final draft

Bifurcation-based parameter tuning in a model of the GnRH pulse and surge generator

We investigate a model of the GnRH pulse and surge generator, with the definite aim of constraining the model GnRH output with respect to a physiologically relevant list of specifications. The alternating pulse and surge pattern of secretion results from the interaction between a GnRH secreting system and a regulating system exhibiting fast-slow dynamics. The mechanisms underlying the behavior of the model are reminded from the study of the Boundary-Layer System according to the "dissection method" principle. Using singular perturbation theory, we describe the sequence of bifurcations undergone by the regulating (FitzHugh-Nagumo) system, encompassing the rarely investigated case of homoclinic connexion. Basing on pure dynamical considerations, we restrict the space of parameter search for the regulating system and describe a foliation of this restricted space, whose leaves define constant duration ratios between the surge and the pulsatility phase in the whole system. We propose an algorithm to fix the parameter values to also meet the other prescribed ratios dealing with amplitude and frequency features of the secretion signal. We finally apply these results to illustrate the dynamics of GnRH secretion in the ovine species and the rhesus monkey

Wild oscillations in a nonlinear neuron model with resets: (II) Mixed-mode oscillations

This work continues the analysis of complex dynamics in a class of bidimensional nonlinear hybrid dynamical systems with resets modeling neuronal voltage dynamics with adaptation and spike emission. We show that these models can generically display a form of mixed-mode oscillations (MMOs), which are trajectories featuring an alternation of small oscillations with spikes or bursts (multiple consecutive spikes). The mechanism by which these are generated relies fundamentally on the hybrid structure of the flow: invariant manifolds of the continuous dynamics govern small oscillations, while discrete resets govern the emission of spikes or bursts, contrasting with classical MMO mechanisms in ordinary differential equations involving more than three dimensions and generally relying on a timescale separation. The decomposition of mechanisms reveals the geometrical origin of MMOs, allowing a relatively simple classification of points on the reset manifold associated to specific numbers of small oscillations. We show that the MMO pattern can be described through the study of orbits of a discrete adaptation map, which is singular as it features discrete discontinuities with unbounded left- and right-derivatives. We study orbits of the map via rotation theory for discontinuous circle maps and elucidate in detail complex behaviors arising in the case where MMOs display at most one small oscillation between each consecutive pair of spikes

Solos em topossequência de veredas das chapadas do Alto Vale do Jequitinhonha, MG: I - caracterização e classificação

In the upper Jequitinhonha valley, state of Minas Gerais, Brazi, there are large plane areas known as chapadas, which are separated by areas dissected by tributaries of the Jequitinhonha and Araçuaí rivers. These dissected areas have a surface drainage system with tree, shrub, and grass vegetation, more commonly known as veredas, i.e., palm swamps. The main purpose of this study was to characterize soil physical, chemical and morphological properties of a representative toposequence in the watershed of the Vereda Lagoa do Leandro, a swamp near Minas Novas, MG, on chapadas, the highlands of the Alto Jequitinhonha region Different soil types are observed in the landscape: at the top - Typic Haplustox (LVA), in the middle slope - Xanthic Haplustox (LA), at the footslope - Xanthic Haplustox, gray color, here called Gray Haplustox (LAC) and, at the bottom of the palm swamp - Typic Albaquult (GXbd). These soils were first morphologically described; samples of disturbed and undisturbed soils were collected from all horizons and subhorizons, to evaluate their essential physical and chemical properties, by means of standard determination of Fe, Al, Mn, Ti and Si oxides after sulfuric extraction. The contents of Fe, Al and Mn, extracted with dithionite-citrate-bicarbonate and oxalate treatments, were also determined. In the well-drained soils of the slope positions, the typical morphological, physical and chemical properties of Oxisols were found. The GXbd sample, from the bottom of the palm swamp, is grayish and has high texture gradient (B/A) and massive structure. The reduction of the proportion of crystalline iron compounds and the low crystallinity along the slope confirmed the loss of iron during pedogenesis, which is reflected in the current soil color. The Si and Al contents were lowest in the LAC soil. There was a decrease of the Fe2O3/TiO2 ratio downhill, indicating progressive drainage restriction along the toposequence. The genesis and all physical and chemical properties of the soils at the footslope and the bottom of the palm swamp of the chapadas of the Alto Jequitinhonha region are strongly influenced by the occurrence of ground water on the surface or near the surface all year long, at present and/or in the past. Total concentrations of iron oxides, Fe d and Fe o in soils of the toposequence studied are related to the past and/or present soil colors and drainage conditions.No Alto Vale do Jequitinhonha - MG ocorrem extensas áreas de relevo aplainado denominadas de chapadas, que estão separadas por áreas dissecadas pelos rios Jequitinhonha e Araçuaí e seus afluentes. Nessas áreas dissecadas é encontrado um sistema de drenagem superficial com vegetação arbóreo-arbustiva e gramíneas, comumente denominado de vereda. O objetivo deste estudo foi caracterizar física, química e morfologicamente os solos de uma topossequência da microbacia da Vereda Lagoa do Leandro, representativa das veredas das chapadas do Alto Jequitinhonha, localizada no município de Minas Novas - MG. Os solos estudados ocupam as seguintes posições na vertente: topo - Latossolo Vermelho Amarelo (LVA); terço médio da vertente - Latossolo Amarelo (LA); sopé - Latossolo Amarelo, de cor cinzenta, aqui denominado Latossolo Acinzentado (LAC); e base da vereda - Gleissolo Háplico (GXbd). Esses solos foram descritos morfologicamente e foram coletadas amostras deformadas e indeformadas em todos os horizontes e sub-horizontes para realização das análises físicas e químicas de rotina, determinação de óxidos de Fe, Al, Mn, Ti e Si após extração por ataque sulfúrico e determinação dos teores de Fe, Al e Mn extraídos por ditionito-citrato-bicarbonato e oxalato. Os solos das posições bem drenadas da vertente apresentaram atributos morfológicos, físicos e químicos típicos da ordem dos Latossolos. Na base da vereda encontra-se o GXbd, que apresenta cores acinzentadas, elevado gradiente textural B/A e estrutura maciça. A diminuição do teor de Fe cristalino e de baixa cristalinidade ao longo da vertente confirmou a perda de Fe durante o processo de pedogênese e refletiu na cor dos solos. Os teores de Si e Al foram mais baixos no LAC. Verificou-se diminuição da relação Fe2O3/TiO2 vertente abaixo, indicando impedimentos à drenagem ao longo da topossequência. A gênese e os atributos dos solos do sopé e da base das veredas das chapadas do Alto Vale do Jequitinhonha - MG são fortemente influenciados pela presença do nível freático na superfície ou próximo à superfície o ano todo, no presente e, ou, no passado. Os teores totais de óxidos de Fe, Fe o e Fe d dos solos da topossequência estudada estão relacionados com as cores dos solos e com condições de drenagem presentes e,ou, pretéritas

Occurrence of microcystins along the Guadiana estuary

Blooms of toxic cyanobacteria develop regularly during summer and early autumn in the Guadiana River (South of Iberian Peninsula). Microcystis aeruginosa, Aphanizomenon flos-aquae, Oscillatoria spp. and Anabaena spp. have been identified in previous studies as the main toxic cyanobacteria present. With the closure of the Alqueva dam and its new policy of water retention, the present project focused on the effect of these new hydrological conditions to toxic cyanobacteria bloom formations in the Guadiana estuary. This article shows data collected from three sampling stations located along the estuary during the spring of 2002. Physical and chemical parameters (temperature, salinity, turbidity and nutrients (dissolved nitrate, silicate and phosphate)) and biological characteristics of the water (chlorophyll a and phytoplankton composition) were evaluated, as well as microcystin (MC) content in particulate material using HPLC-PDA. Microcystis sp. was the dominant toxic cyanobacteria in the collected water samples. Results suggest the existence of a longitudinal gradient in toxin content directly related to the development of temperature, salinity and nutritional ratio gradients along the estuary, and indirectly related to the turbidity of the water. At least five MC variants were observed and quantified as MC-LR equivalents (MC-LR Equiv.). The total MC concentrations in particulate material varied from 0.0 to above 1.0 μg MCLR Equiv.·L-1, with higher values always observed at the freshwater station. Finally, higher dissolved silica concentrations were found in the water column when compared to results from previous years. These differences reflect changes in the Guadiana ecohydrological status which are probably related to the Alqueva dam construction.La formación de blooms de cianobacterias tóxicas se produce regularmente durante los meses de verano y principios del otoño en el Río Guadiana (Sur de la Península Ibérica). Entre las diferentes cianobacterias potencialmente tóxicas estudios previos han identificado a especies como Microcystis aeruginosa, Aphanizomenon flos-aquae, Oscillatoria spp. y Anabaena spp. Con la puesta en funcionamiento de la presa de Alqueva y su nueva política de retención de aguas, se elaboró el presente proyecto enfocado hacia el estudio del efecto de las nuevas condiciones hidrológicas sobre la formación de blooms de cianobacterias tóxicas en el estuario del Guadiana. Este artículo muestra los datos obtenidos en tres estaciones de muestreo localizadas a lo largo del estuario del Guadiana durante la primavera del año 2002. Se analizaron parámetros físico-químicos (temperatura, salinidad, turbidez y nutrientes (nitrato, silicato y fosfato disueltos)) y características biológicas del agua (clorofila a y composición fitoplanctónica), así como el contenido de microcistina (MC) en el material particulado cuantificado por HPLC-PDA, en tres estaciones de muestreo situadas a lo largo del estuario. Microcystis sp. fue la cianobacteria tóxica predominante en las muestras de agua analizadas. Los resultados sugieren la existencia de un gradiente longitudinal en el contenido de toxinas directamente relacionado con el desarrollo de gradientes longitudinales de temperatura, salinidad y cocientes nutricionales a lo largo del estuario, e indirectamente relacionado con la turbidez del agua. Se observaron al menos cinco variantes de MC que se cuantificaron como equivalentes de MC-LR (Equiv. MC-LR). La concentración total de MC en material particulado varió de 0.0 a más de 1.0 μg Equiv. MC-LR·L-1, observándose siempre los valores superiores en la estación de agua dulce. Finalmente, fueron encontradas concentraciones de silicato disuelto en la columna de agua superiores a las de años anteriores. Estas diferencias reflejan cambios en el estado ecohidrológico del Guadiana probablemente relacionados con la construcción de la presa de Alqueva

DynPeak : An algorithm for pulse detection and frequency analysis in hormonal time series

The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedback exerted on the pituitary level. Hence, there is a real need for robust IPI detection algorithms. In this article, we present an algorithm for the monitoring of LH pulse frequency, basing ourselves both on the available endocrinological knowledge on LH pulse (shape and duration with respect to the frequency regime) and synthetic LH data generated by a simple model. We make use of synthetic data to make clear some basic notions underlying our algorithmic choices. We focus on explaining how the process of sampling affects drastically the original pattern of secretion, and especially the amplitude of the detectable pulses. We then describe the algorithm in details and perform it on different sets of both synthetic and experimental LH time series. We further comment on how to diagnose possible outliers from the series of IPIs which is the main output of the algorithm.Comment: Nombre de pages : 35 ; Nombre de figures : 16 ; Nombre de tableaux :

Relações pedológicas e isotópicas de uma turfeira na Serra do Espinhaço Meridional - MG

The evolution of organic matter sources in soil is related to climate and vegetation dynamics in the past recorded in paleoenvironmental Quaternary deposits such as peatlands. For this reason, a Histosol of the mineralotrophic peatland from the Pau-de-Fruta Special Protection Area - SPA, Espinhaço Meridional, State of Minas Gerais, was described and characterized to evidence the soil constituent materials and properties as related to changes in environmental conditions, supported by the isotopic and elementary characterization of soil C and N and 14C ages. Samples were collected in a depression at 1,350 m asl, where Histosols are possibly more developed due to the great thickness (505 cm). Nowadays, the area is colonized by vegetation physiognomies of the Cerrado Biome, mainly rocky and wet fields (Campo Rupestre and Campo Úmido), aside from fragments of Semidecidual Seasonal Forest, called Capões forests. The results this study showed that early the genesis of the analyzed soil profile showed a high initial contribution of mostly herbaceous organic matter before 8,090 ± 30 years BP (14C age). In the lower-mid Holocene, between 8,090 ± 30 years AP (14C age) to ± 4,100 years BP (interpolated age), the vegetation gradually became more woody, with forest expansion, possibly due to increased humidity, suggesting the existence of a more woody Cerrado in the past than at present. Drier climate conditions than the current were concluded ± 2,500 years BP (interpolated age) and that after 430 years BP (14C age) the forest gave way to grassland, predominantly. After the dry season, humidity increased to the current conditions. Due to these climate fluctuations during the Holocene, three decomposition stages of organic matter were observed in the Histosols of this study, with prevalence of the most advanced (sapric), typical of a deposit in a highly advanced stage of pedogenetic evolution.A evolução das fontes de matéria orgânica no solo está relacionada com a dinâmica do clima e da vegetação durante épocas passadas, representadas pelos registros paleoambientais em depósitos quaternários como as turfeiras. Por esta razão, um organossolo da turfeira mineralotrófica da Área de Proteção Especial - APE Pau-de-Fruta, Serra do Espinhaço Meridional, MG foi descrito e caracterizado com a finalidade de evidenciar os materiais constituintes e os atributos do solo relacionados às mudanças das condições do ambiente, apoiados pela caracterização isotópica e elementar do C e N do solo e idades 14C. A amostragem foi realizada em uma depressão localizada a 1.350 m de altitude, onde possivelmente os Organossolos são mais desenvolvidos, devido à elevada espessura de 505 cm. A turfeira atualmente é colonizada por fisionomias vegetais do Bioma Cerrado, principalmente Campo Rupestre e Campo Úmido, além de alguns redutos de ilhas de Floresta Estacional Semidecidual, denominados Capões de Mata. Os resultados deste estudo demonstraram que a gênese inicial do perfil de solo estudado, antes de 8.090 ± 30 anos AP (idade 14C), apresentou elevada contribuição de uma matéria orgânica mais herbácea, e gradualmente no Holoceno Inferior/Médio, entre 8.090 ± 30 anos AP (idade14C) a ± 4.100 anos AP (idade interpolada), a vegetação tornou-se mais lenhosa, com expansão de uma mata, possivelmente devido ao aumento de umidade, sugerindo a existência no passado de um Cerrado mais lenhoso que o atual. Condições de um clima mais seco que o atual foi verificado em ± 2.500 anos AP (idade interpolada) e após 430 anos AP (idade14C), quando a mata regrediu, predominando a vegetação de campo. Após o período mais seco, a umidade aumentou até as condições atuais. Em meio a essas flutuações climáticas durante o Holoceno, o Organossolo em estudo apresentou três estádios de decomposição da matéria orgânica, com predomínio do mais avançado (sáprico), característico de um depósito em estágio de evolução pedogenético altamente avançado.(FAPESP) São Paulo Research Foundatio