Nondecaying Hydrodynamic Interactions along Narrow Channels.

Particle-particle interactions are of paramount importance in every multibody system as they determine the collective behavior and coupling strength. Many well-known interactions such as electrostatic, van der Waals, or screened Coulomb interactions, decay exponentially or with negative powers of the particle spacing r. Similarly, hydrodynamic interactions between particles undergoing Brownian motion decay as 1/r in bulk, and are assumed to decay in small channels. Such interactions are ubiquitous in biological and technological systems. Here we confine two particles undergoing Brownian motion in narrow, microfluidic channels and study their coupling through hydrodynamic interactions. Our experiments show that the hydrodynamic particle-particle interactions are distance independent in these channels. This finding is of fundamental importance for the interpretation of experiments where dense mixtures of particles or molecules diffuse through finite length, water-filled channels or pore networks.U.F.K. was supported by an ERC starting grant (PassMembrane 261101). S.P. acknowledges funding from a Leverhulme Early Career Fellowship. K.M. was supported by a grant from the EPSRC. E.L. was supported by Marie Curie CIG grant from EU.This is the author accepted manuscript. The final version is available from APS via http://dx.doi.org/10.1103/PhysRevLett.115.03830

Pipeline break detection using pressure transient monitoring

Sudden pipe breaks occur in water transmission pipelines and distribution mains. The consequences of these breaks can be very expensive because of the service interruption, the cost of repair, and damage to surrounding property and infrastructure. The costs associated with the pipeline breaks can be reduced by minimizing the break detection and location time. This paper presents a new continuous monitoring approach for detecting and locating breaks in pipelines. A sudden pipe break creates a negative pressure wave that travels in both directions away from the break point and is reflected at the pipeline boundaries. Using the pressure data measured at one location along the pipeline, the timing of the initial and reflected transient waves induced by the break determines the location of the break. The magnitude of the transient wave provides an estimate of the break size. The continuous monitoring technique uses a modified two-sided cumulative sum (CUSUM) algorithm to detect abrupt break-induced changes in the pressure data. The adaptive tuning of CUSUM parameters is implemented to detect breaks of differing sizes and opening times. The continuous monitoring technique is verified by using results from both laboratory and field experiments and shows potential for detecting and locating sudden breaks in real pipelines.Dalius Misiunas, John Vítkovský, Gustaf Olsson, Angus Simpson, M.ASCE, and Martin Lambert

Concentración de urea en leche, producción y condición corporal, de cabras con suplementación en el norte de Córdoba, Argentina

Ponencia presentada en la XXIII Reunión de ALPA. IV Congreso Internacional de Producción Animal Tropical. La Habana, Cuba, 18 al 22 de noviembre de 2013En el N y NO de la provincia de Córdoba, con lluvias primavero-estivales y pariciones a fines de otoño, las cabras paren y amamantan sus crías bajo una restricción alimentaria que disminuye en primavera cuando se inician las lluvias. A partir de octubre mejora la condición corporal (CC) y en noviembre-diciembre la producción de leche (PL). El nivel de urea en leche (UL) relacionado con PL y CC, podría revelar el estatus nutricional de las hembras en estas condiciones de producción y explicar su curva de lactancia. Los objetivos fueron determinar los valores promedio de UL y relacionarlos con CC, PL y nivel de producción de leche (NPL) cuando reciben una suplementación dietaria valorada y constante. Se utilizaron 20 cabras paridas en junio de segunda o más lactancias. Al pastoreo natural se agregó una ración de heno de alfalfa y grano de maíz, (2.50Mcal EM y 132.4 g de PB/cabra/día). La PL se determinó por controles lecheros quincenales entre 80±15 y 200±15 días de lactancia, la UL por Reactivo Wiener lab. Se utilizó un Modelo Lineal Mixto (InfoStat, 2012) para medidas repetidas en el tiempo. Los resultados se analizaron considerando el total de las hembras y diferenciadas por NPL: Alta PL y Baja PL. Hubo diferencias entre muestras en las tres variables estudiadas. La CC incrementó (p<0,05) en octubre, una quincena antes de la UL (p<0.001) y un mes antes de la PL (p<0.001). La concentración promedio de UL durante la etapa de restricción fue de 17.96±0.95 mg % e incrementó y se estabilizó a partir de noviembre en 40.25±0.95 mg % (p<0,05). El análisis por NPL mostró diferencias entre grupos sólo en PL (p<0.001). Se concluye que los valores de urea asociados con la CC permitirían interpretar de manera estratégica la eficiencia de utilización del alimento y condición metabólica de las cabras si se registran con periodicidad.Milk urea concentration, milk production and body condition,in goatsfeed supplemented in the north of Córdoba, Argentina. In the N and NW of Córdoba province with rains in spring-summer period, and lambing in late autumn, goats give birth and nurse their offspring under a food restriction that decreases in spring when the rains start. From October improves body condition (BC), and in November-December milk production (MP). The milk urea level (MUL) related to MP and BC, could reveal the nutritional status of females in these conditions of production and explain their lactation curve. The objective was to determine the average values of MUL and relate them with BC, MP and level of MP (MPL). Twenty calved in June goats were used, of second or more lactations. To natural grazing a ration of alfalfa hay and corn grain was added, (2.50 Mcal ME and PB 132.4 g / goat / day). The MP was determined twice monthly by milk controls between 80 ± 15 and 200 ± 15 days of lactation, the MUL for Uremia-Wiener. A Linear Mixed Model (InfoStat, 2012) for repeated measures over time was used. The results were analyzed considering the total of the females and differentiated MPL: High MP and Low MP. There were differences between samples in the three studied variables. The CC increased (p <0.05) in October, a fortnight before the MUL (p <0.001) and a month before the MP (p <0.001). The average concentration of MUL during the restriction period was 17.96 ± 0.95 mg/dL and increased and stabilized from November to 40.25 ± 0.95 mg/dL (p <0,05). MPL analysis showed group differences in MP only (p <0.001). It is concluded that urea values associated with BC allow the strategically interpretation of feed utilization efficiency and metabolic condition of goats whether these dataare recorded periodically.Fil: Rodríguez, Virginia A. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Alonso, Armonía. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Menajovsky, Jorge R. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Misiunas, Susana Beatríz. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Carcedo, Jorge Alberto. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Clausen, Liliana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina

Perfil nitrogenado-mineral y condición corporal de cabras con producción de leche en secano en el noroeste de Córdoba, Argentina

Ponencia presentada en la XXIII Reunión de ALPA. IV Congreso Internacional de Producción Animal Tropical. La Habana, Cuba, 18 al 22 de noviembre de 2013.Se estudiaron indicadores productivos y fisiológicos de cabras en lactancia, luego de pariciones de otoño, en un sistema de producción pastoril tradicional, con más de 200 animales. Las hembras utilizadas transcurrían la primera mitad de la lactancia con restricción alimentaria. El objetivo fue analizar las variaciones de CC, produccción de leche (PL) y concentraciones plasmáticas de urea, albumina (Alb), calcio y fósforo y evaluar las respuestas de las hembras a esta situación nutricional. Las cabras se categorizaron según ninel de producción (NPL): Alta PL (n= 13) y Baja PL (n=13). La PL se determinó por pesada (g/día) cada 20 días durante el periodo 70±10 y 190±10 días de lactancia. La CC por palpación lumbar y esternal (escala 1-5) y los metabolitos plasmáticos se midieron utilizando reactivos Wiener Lab.. Se ajustó un Modelo Lineal Mixto para datos longitudinales (InfoStat, 2012). Con excepción de albúmina, se observó interacción de todas las variables (PL, urea, P, Ca, CC) con el tiempo de lactancia (p<0.001). Ninguno de estos parámetros tuvo interacción con NPL. La CC disminuyó (p<0.05) durante el mes de setiembre y recuperó el valor inicial en diciembre. La urea plasmática tuvo correlación negativa con CC y con mm de lluvia anual acumulada. Las cabras de Baja PL, no mostraron diferencias en PL durante el periodo estudiado. Las de Alta PL tuvieron niveles de producción superiores a 1000 g/día en los tres primeros controles, un descenso (P<0.05) en noviembre, volviendo a los valores iniciales en el mes de diciembre. Las concentraciones promedio de fósforo (5.93± 0.17 mg/dL) fueron similares a los hallados en la bibliografía y los de calcio (7.65 ± 0.12 mg/dL) ligeramente menores. Se concluye, que el registro de las variaciones de CC junto con la medición de metabolitos sanguíneos, en particular la urea, podría utilizarse como herramienta para detectar desbalances metabólicos, en cabras lactantes con restricción alimentaria.Nitrogenous-mineral profile and body condition of dairy goats in rainfed northwest of Córdoba, Argentina. Physiological and productive indicators in lactating goats, after fall calving, in a traditional pastoral system with over 200 animals, were studied. Females used went by the first half of lactation with food restriction. The aim was to analyze variations BC, milk produccción (MP) and plasma concentrations of urea, albumin (Alb), calcium and phosphorus, and evaluate females response to this nutritional situation. The goats were categorized according to level of milk production (MPL): High PL (n = 13) and Low PL (n = 13). The MPL was determined by weighing (g / day) every 20 days during the period 70 ± 10 and 190 ± 10 days of lactation. The BCwas determinated by lumbar and sternal palpation (scale 1-5) and plasma metabolites were measured using reagents Wiener Lab. Data was adjusted to a Mixed Linear Model for longitudinal data (InfoStat, 2012). With the exception of albumin, an interaction of all the variables (PL, urea, P, Ca, Cc) with time of lactation (p <0.001) was observed. None of these parameters had interaction with MPL. The BC decreased (p <0.05) during September and recovered the initial value in December. Plasma urea level was negatively correlated with BC and accumulated annual rainfall (mm). Low PL goats showed no differences in MP during the study period. High PL goats production levels were above 1000 g / day in the first three controls, a decrease (P <0.05) in November, returning to baseline levels in December. The average concentrations of phosphorus (5.93 ± 0.17 mg / dL) were similar to those found in the literatura, while the calcium one (7.65 ± 0.12 mg / dL) were slightly lower. We conclude that the registry of changes in BC together with the measurement of blood metabolites, particularly urea, could be used as a tool to detect metabolic imbalances in food- restricted lactating goats.Fil: Rodríguez, Virginia A. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Alonso, Armonía. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Clausen, Liliana. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Menajovsky, Jorge R. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Misiunas, Susana Beatríz. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina.Fil: Carcedo, Jorge Alberto. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; Argentina

The baltic states: Years of dependence, 1980–1986

In 1983 we published a book entitled The Baltic States: Years of Dependence 1940-1980.1 The present article represents an update chapter which reviews the years 1980–1986. Compared to the late 1970s and the early 1980s, a period of stagnation, 1987 was a singularly difficult time for writing recent Soviet and Baltic history. CPSU General Secretary Mikhail Gorbachev was trying to overcome the general stagnation in which the Soviet Union found itself, and the outcome of his increasingly dramatic effort remains uncertain. Hence, the historical perspective for our interpretation of recent events is missing. Will economic and technological growth in the USSR be achieved without appreciable political changes, or will liberalization be the price for technological progress? If liberalization is needed, will Gorbachev be able to pay the price, or will he maintain the past mix of authoritarian and totalitarian features even at the cost of continued economic stagnation? If Gorbachev chooses liberalization, will more conservative bureaucratic forces eventually topple him? If the Soviet leadership opts for continued economic stagnation, will the Soviet population continue to be submissive indefinitely? As before, Baltic history in the 1980s continues to depend on the interplay of local aspirations with decisions made in Moscow. © 1989, Taylor &amp; Francis Group, LLC. All rights reserved

The baltic states: Years of dependence, 1980–1986

In 1983 we published a book entitled The Baltic States: Years of Dependence 1940-1980.1 The present article represents an update chapter which reviews the years 1980–1986. Compared to the late 1970s and the early 1980s, a period of stagnation, 1987 was a singularly difficult time for writing recent Soviet and Baltic history. CPSU General Secretary Mikhail Gorbachev was trying to overcome the general stagnation in which the Soviet Union found itself, and the outcome of his increasingly dramatic effort remains uncertain. Hence, the historical perspective for our interpretation of recent events is missing. Will economic and technological growth in the USSR be achieved without appreciable political changes, or will liberalization be the price for technological progress? If liberalization is needed, will Gorbachev be able to pay the price, or will he maintain the past mix of authoritarian and totalitarian features even at the cost of continued economic stagnation? If Gorbachev chooses liberalization, will more conservative bureaucratic forces eventually topple him? If the Soviet leadership opts for continued economic stagnation, will the Soviet population continue to be submissive indefinitely? As before, Baltic history in the 1980s continues to depend on the interplay of local aspirations with decisions made in Moscow. © 1989, Taylor &amp; Francis Group, LLC. All rights reserved