Epizootiološko istraživanje slinavke i šapa u Sudanu: stanje nakon dva desetljeća

In order to update information on the situation regarding foot and mouth disease (FMD) in the Sudan, a serosurvey and disease survey were conducted. Recently collected data on FMD in the Sudan showed that FMD is a major constraint to animal production in the country. It presents no threat nor does it cause mild disease in sheep and goats. The disease, with obvious clinical signs, has been detected in cattle only, and is caused by serotype O and SAT 2. Seasonal occurrence of the disease in the cold, dry season has been observed and animal movement seems to play a major role in virus dissemination. A total of 1,069 sera were collected from cattle, sheep, goats, and camel, from seven states in the Sudan, for the detection of antibodies to FMDV. Application of liquid phase blocking (LPB) ELISA revealed that antibodies to four serotypes were present in ruminants; namely O, A, SAT 1 and SAT 2. No antibodies to FMDV were detected in camel sera. The results differed from early reports regarding the prevalence of serotype specifi c antibodies in different species; for instance, in cattle, the antibodies to type A (78.13%) surpassed that of type O (69.39%) and the antibodies to type SAT 2 (44%) surpassed that of type SAT 1 (20.2%). This work elucidates the current epidemiology of FMD in some parts of the Sudan.Radi pružanja informacija o sadašnjem stanju slinavke i šapa u Sudanu provedena su serološka istraživanja te je prikazana njezina pojavnost. Svježe prikupljeni podatci o pojavi slinavke i šapa u Sudanu pokazali su da ona predstavlja veliku prepreku životinjskoj proizvodnji u toj zemlji. U ovaca i koza javlja se kao blaga bolest i ne predstavlja veliku prijetnju, dok se u goveda javlja s očitim kliničkim znakovima, a uzrokovana je serotipovima O i SAT 2. Bolest se javlja sezonski u hladnoj i suhoj sezoni, a promet životinjama ima glavnu ulogu u širenju virusa. Ukupno je bilo prikupljeno 1069 uzoraka seruma goveda, ovaca, koza i deva podrijetlom iz sedam država u Sudanu radi pretrage na prisutnost protutijela za virus slinavke i šapa. Blokirajućim imunonenzimnim testom dokazana su protutijela za četiri serotipa virusa: O, A, SAT 1 i SAT 2. Protutijela za virus slinavke i šapa nisu bila dokazana u uzorcima seruma deva. Rezultati se razlikuju od ranijih izvješća s obzirom na prevalenciju specifi čnih protutijela u različitih vrsta. Npr., specifi čna protutijela za serotip A dokazana su u 78,13% goveda, za serotip O u 69,39%, serotip SAT 2 u 44% te serotip SAT 1 u 20,2% goveda. U radu je prikazano sadašnje epizootiološko stanje slinavke i šapa u nekim dijelovima Sudana

A ’Millipede’ scanner model - Energy consumption and performance

This short report (1) describes an energy model for the seek and read/write operations in a mass-balanced Y-scanner for parallel-probe storage by IBM [1] and (2) updates the settings of the MEMS model in DiskSim with recent published figures from this XY-scanner. To speedup system simulations, a straight forward second-order model is used without control loop. Read/write operation is modeled by quasi-static calculations. To approximate seek behavior, ’bang-bang’ control is assumed; the result is close to the actual behavior with control loop [2]. Unfortunately, no energy measurements were available to validate the model. Using the proposed energy model, we are able to study the energy consumption of a MEMS-based storage device for different application areas and file systems

Uplink Performance of Time-Reversal MRC in Massive MIMO Systems Subject to Phase Noise

Multi-user multiple-input multiple-output (MU-MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information (CSI). In particular, we consider two distinct operation modes, namely when the phase noise processes at the $M$ BS antennas are identical (synchronous operation) and when they are independent (non-synchronous operation). We analyze a linear and low-complexity time-reversal maximum-ratio combining (TR-MRC) reception strategy. For both operation modes we derive a lower bound on the sum-capacity and we compare their performance. Based on the derived achievable sum-rates, we show that with the proposed receive processing an $O(\sqrt{M})$ array gain is achievable. Due to the phase noise drift the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users.Comment: 13 pages, 6 figures, 2 tables, IEEE Transactions on Wireless Communications (accepted

Functional materials synthesis by surface-supported chemistry

96 p.La química orgánica es un campo de investigación extremadamente maduro cuyos continuos avances han ido permitiendo la generación de materiales cada vez más refinados, caracterizados por fascinantes propiedades físicas y químicas. La aplicación de tales compuestos orgánicos nanoestructurados ha ido generando importantes impulsos al campo de la nanociencia. En los últimos 15 años se está desarrollando una nueva alternativa a la química convencional: la síntesis en superficies (¿on-surface synthesis¿, OSS) bajo condiciones de ultra alto vacío. Este nuevo planteamiento ha abierto nuevas puertas para la formación de nanoestructuras de carbono que no están al alcance de los métodos convencionales. Su aplicación para la síntesis de materiales orgánicos de baja dimensionalidad y con precisión atómica está mostrando un crecimiento en auge y tiene un enorme potencial para aplicaciones que incluyen nuevas tecnologías cuánticas.En esta tesis, este novedoso enfoque se aplica al crecimiento de diferentes tipos de materiales, seguido de una caracterización integral de las propiedades estructurales, químicas y electrónicas de los productos intermedios y finales. Para tal fin se ha utilizado principalmente la microscopía túnel de barrido a baja temperatura (4,3 K) en varios modos de medición, complementados con cálculos teóricos (DFT y métodos de partículas de sonda). En concreto se han estudiado los siguientes sistemas:(i) Química metal-orgánica, en la que se muestra la manera de controlar la estructura de enlace de tiolatos de oro y su estereoespecíficidad variando los parámetros de reacción en la superficie (recubrimiento y temperatura del sustrato).(ii) Química basada en pirenos. Usando moléculas de pireno funcionalizadas con alquinos, se investiga el efecto de los complejos metal-orgánicos descritos anteriormente en las reacciones de acoplamiento de alquinos. Los complejos metal-orgánicos no solo modifican el resultado de la reacción, sino que también reducen el umbral de la temperatura de activación, siendo por tanto un excelente ejemplo de síntesis en superficie de segundo orden (es decir, OSS del catalizador para dirigir nuevas reacciones de OSS). De otro lado, también se han utilizado pirenos funcionalizados con dos tipos de grupos funcionales distintos, como son los alquinos y átomos de Br. La presencia de ambos grupos funcionales permite nuevo abanico de reacciones que incluyen el tanto el acoplamiento de alquinos o el acoplamiento cruzado. El análisis de los productos resultantes y su abundancia tras tratamientos de calentamiento muestran una dominancia del acoplamiento de Glaser (acoplamiento de alquinos con pérdida de hidrógeno) como reacción inicial. Sin embargo, al utilizar un precursor no halogenado se observa una prevalencia de un acoplamiento sin pérdida de hidrógeno y una total ausencia de acoplamiento Glaser, evidenciando el papel crítico del Br en la reactividad de alquinos. Es importante destacar también que una comparación sistemática de las propiedades electrónicas de las diferentes estructuras de los productos ha permitido trazar importantes relaciones entre la estructura y las propiedades de los diversos tipos de acoplamientos entre pirenos.(iii) Química basada en aceno. Se ha estudiado la síntesis de acenos de gran tamaño, en concreto de heptaceno sobre Ag(001), a partir de precursores moleculares de tetrahidroheptaceno con y sin funcionalización adicional por átomos de Br. Se ha encontrado una variedad de productos intermedios que a menudo resultan de eventos de migración de hidrógeno. Sin embargo, el heptaceno es el producto final de los dos precursores y muestra un orbital LUMO completamente cargado. Centrándonos en los intermedios, se observa cómo dos átomos de carbono con hibridación sp3 en el segundo anillo de dihidroheptaceno son suficientes para causar el auto-desacoplamiento electrónico de la molécula y el sustrato. Se han investigado asimismo las señales magnéticas, evidenciadas en resonancias Kondo, asociadas a determinados escenarios de carga. Finalmente, utilizando precursores basados en acenos se ha explorado el impacto del sustrato en las reacciones de acoplamiento. En concreto se han utilizado superficies de Au(111) y Au(110), así como precursores de antraceno funcionalizados con halógenos y metilos. Sobre Au(111), una superficie atómicamente plana, se encuentran cinco tipos de productos covalentes, siendo el starphene con simetría de eje ternario el producto dominante. Por contra, sobre la superficie reconstruida de Au(110) 2×1, su simetría uniaxial promueve la formación de polímeros lineales no benzenoides.Esta tesis contribuye al campo de la ciencia de superficies, mostrando la posibilidad de sintetizar una variedad de nanomateriales novedosos basados en carbono mediante la síntesis en superficie, así como mediante la caracterización detallada sus propiedades. La comprensión de las propiedades físico-químicas de estos materiales avanzados es un paso de gran relevancia hacia sus futuras aplicaciones.The mature research field of conventional solution-based chemistry has allowed for a continuous generation of increasingly refined materials with amazing physical and chemical properties. This has contributed to great advances in the field of organic nanomaterials. The development of the recently revealed surface-supported synthesis under ultrahigh vacuum conditions has opened new doors for the formation of defect-free low-dimensional carbon nanostructures that are not achievable by conventional means. This new field, typically termed on-surface synthesis (OSS), is lately showing a booming growth that resonates with almost all the requirements for promising quantum size materials with tunable physicochemical properties.In this thesis, this novel approach is applied for the growth of a variety of materials, followed by a comprehensive characterization of the structural, chemical and electronic properties of the intermediates and end-products. This is achieved mainly by scanning tunneling microscopy operating at low temperature (4.3 K) in various measurement modes, assisted by theoretical calculations (DFT and probe particle methods). In particular, the following systems have been studied:(i) Metal-organic chemistry, in which the stereospecific coupling motif of gold thiolates is found to be controllable by varying the on-surface reaction parameters (i.e. coverage and substrate temperature).(ii) Pyrene-based chemistry. With alkyne-functionalized pyrene molecules, the impact of the presence of metal-organic complexes on alkyne coupling reactions is investigated. The complexes do not only modify the reaction outcome, but also reduce its activation temperature threshold, becoming an excellent example of second-order on-surface synthesis (i.e. OSS of catalyst to steer following OSS reactions). Secondly, pyrenes are used that are functionalized with alkynes and also Br atoms, allowing for alkyne homo- and cross-coupling reactions. The resulting products and their relative abundance are explored thoroughly after different annealing steps, revealing a dominant Glaser-coupling product upon heating. The absence of the latter when using non-halogenated precursor evidenced the role of Br in this coupling reaction. Importantly, a systematic comparison of the electronic properties of the different product structures has allowed drawing important structure-property relations with regard to the various inter-pyrene coupling motifs.(iii) Acene-based chemistry. The synthesis of higher acenes is studied, in particular heptacene on Ag(001), starting from tetrahydroheptacene molecular precursors with and without additional functionalization by Br atoms. A variety of stable reaction intermediates is found, often resulting from hydrogen migration events. However, heptacene is the end-product from the two precursors and displays a fully charged LUMO orbital. Focusing on the intermediates, two sp3-hybridized carbon atoms present at the second ring of dihydroheptacene are shown as sufficient self-decoupling factors. Magnetic Kondo fingerprints associated to specific charging scenarios are investigated. Finally, the impact of the surface structure on coupling reactions with acene-based precursors is then explored. More specifically, Au(111) and Au(110) surfaces, as well as anthracene precursors functionalized with halogen and methyls are used with this aim. On Au(111), the atomically flat surface, five covalent coupling motifs are found, with the 3-fold symmetric starphene showing the highest occurrence upon annealing. In contrast, on Au(110), being a 2×1 reconstructed surface, the uniaxial symmetry of the surface promotes the formation of mainly linear non-benzenoid polymers along the grooves of this substrate.This thesis contributes to the surface science field by showing the possibility to synthesize a variety of novel carbon-based nanomaterials using on-surface synthesis methods. The second main contribution is the detailed characterization of the produced materials using surface-sensitive techniques assisted by theoretical calculations. A deep understanding of the physicochemical properties of these materials is a crucial step forward towards their ultimately progressing applications.CFM; CSI

Functional materials synthesis by surface-supported chemistry

96 p.La química orgánica es un campo de investigación extremadamente maduro cuyos continuos avances han ido permitiendo la generación de materiales cada vez más refinados, caracterizados por fascinantes propiedades físicas y químicas. La aplicación de tales compuestos orgánicos nanoestructurados ha ido generando importantes impulsos al campo de la nanociencia. En los últimos 15 años se está desarrollando una nueva alternativa a la química convencional: la síntesis en superficies (¿on-surface synthesis¿, OSS) bajo condiciones de ultra alto vacío. Este nuevo planteamiento ha abierto nuevas puertas para la formación de nanoestructuras de carbono que no están al alcance de los métodos convencionales. Su aplicación para la síntesis de materiales orgánicos de baja dimensionalidad y con precisión atómica está mostrando un crecimiento en auge y tiene un enorme potencial para aplicaciones que incluyen nuevas tecnologías cuánticas.En esta tesis, este novedoso enfoque se aplica al crecimiento de diferentes tipos de materiales, seguido de una caracterización integral de las propiedades estructurales, químicas y electrónicas de los productos intermedios y finales. Para tal fin se ha utilizado principalmente la microscopía túnel de barrido a baja temperatura (4,3 K) en varios modos de medición, complementados con cálculos teóricos (DFT y métodos de partículas de sonda). En concreto se han estudiado los siguientes sistemas:(i) Química metal-orgánica, en la que se muestra la manera de controlar la estructura de enlace de tiolatos de oro y su estereoespecíficidad variando los parámetros de reacción en la superficie (recubrimiento y temperatura del sustrato).(ii) Química basada en pirenos. Usando moléculas de pireno funcionalizadas con alquinos, se investiga el efecto de los complejos metal-orgánicos descritos anteriormente en las reacciones de acoplamiento de alquinos. Los complejos metal-orgánicos no solo modifican el resultado de la reacción, sino que también reducen el umbral de la temperatura de activación, siendo por tanto un excelente ejemplo de síntesis en superficie de segundo orden (es decir, OSS del catalizador para dirigir nuevas reacciones de OSS). De otro lado, también se han utilizado pirenos funcionalizados con dos tipos de grupos funcionales distintos, como son los alquinos y átomos de Br. La presencia de ambos grupos funcionales permite nuevo abanico de reacciones que incluyen el tanto el acoplamiento de alquinos o el acoplamiento cruzado. El análisis de los productos resultantes y su abundancia tras tratamientos de calentamiento muestran una dominancia del acoplamiento de Glaser (acoplamiento de alquinos con pérdida de hidrógeno) como reacción inicial. Sin embargo, al utilizar un precursor no halogenado se observa una prevalencia de un acoplamiento sin pérdida de hidrógeno y una total ausencia de acoplamiento Glaser, evidenciando el papel crítico del Br en la reactividad de alquinos. Es importante destacar también que una comparación sistemática de las propiedades electrónicas de las diferentes estructuras de los productos ha permitido trazar importantes relaciones entre la estructura y las propiedades de los diversos tipos de acoplamientos entre pirenos.(iii) Química basada en aceno. Se ha estudiado la síntesis de acenos de gran tamaño, en concreto de heptaceno sobre Ag(001), a partir de precursores moleculares de tetrahidroheptaceno con y sin funcionalización adicional por átomos de Br. Se ha encontrado una variedad de productos intermedios que a menudo resultan de eventos de migración de hidrógeno. Sin embargo, el heptaceno es el producto final de los dos precursores y muestra un orbital LUMO completamente cargado. Centrándonos en los intermedios, se observa cómo dos átomos de carbono con hibridación sp3 en el segundo anillo de dihidroheptaceno son suficientes para causar el auto-desacoplamiento electrónico de la molécula y el sustrato. Se han investigado asimismo las señales magnéticas, evidenciadas en resonancias Kondo, asociadas a determinados escenarios de carga. Finalmente, utilizando precursores basados en acenos se ha explorado el impacto del sustrato en las reacciones de acoplamiento. En concreto se han utilizado superficies de Au(111) y Au(110), así como precursores de antraceno funcionalizados con halógenos y metilos. Sobre Au(111), una superficie atómicamente plana, se encuentran cinco tipos de productos covalentes, siendo el starphene con simetría de eje ternario el producto dominante. Por contra, sobre la superficie reconstruida de Au(110) 2×1, su simetría uniaxial promueve la formación de polímeros lineales no benzenoides.Esta tesis contribuye al campo de la ciencia de superficies, mostrando la posibilidad de sintetizar una variedad de nanomateriales novedosos basados en carbono mediante la síntesis en superficie, así como mediante la caracterización detallada sus propiedades. La comprensión de las propiedades físico-químicas de estos materiales avanzados es un paso de gran relevancia hacia sus futuras aplicaciones.The mature research field of conventional solution-based chemistry has allowed for a continuous generation of increasingly refined materials with amazing physical and chemical properties. This has contributed to great advances in the field of organic nanomaterials. The development of the recently revealed surface-supported synthesis under ultrahigh vacuum conditions has opened new doors for the formation of defect-free low-dimensional carbon nanostructures that are not achievable by conventional means. This new field, typically termed on-surface synthesis (OSS), is lately showing a booming growth that resonates with almost all the requirements for promising quantum size materials with tunable physicochemical properties.In this thesis, this novel approach is applied for the growth of a variety of materials, followed by a comprehensive characterization of the structural, chemical and electronic properties of the intermediates and end-products. This is achieved mainly by scanning tunneling microscopy operating at low temperature (4.3 K) in various measurement modes, assisted by theoretical calculations (DFT and probe particle methods). In particular, the following systems have been studied:(i) Metal-organic chemistry, in which the stereospecific coupling motif of gold thiolates is found to be controllable by varying the on-surface reaction parameters (i.e. coverage and substrate temperature).(ii) Pyrene-based chemistry. With alkyne-functionalized pyrene molecules, the impact of the presence of metal-organic complexes on alkyne coupling reactions is investigated. The complexes do not only modify the reaction outcome, but also reduce its activation temperature threshold, becoming an excellent example of second-order on-surface synthesis (i.e. OSS of catalyst to steer following OSS reactions). Secondly, pyrenes are used that are functionalized with alkynes and also Br atoms, allowing for alkyne homo- and cross-coupling reactions. The resulting products and their relative abundance are explored thoroughly after different annealing steps, revealing a dominant Glaser-coupling product upon heating. The absence of the latter when using non-halogenated precursor evidenced the role of Br in this coupling reaction. Importantly, a systematic comparison of the electronic properties of the different product structures has allowed drawing important structure-property relations with regard to the various inter-pyrene coupling motifs.(iii) Acene-based chemistry. The synthesis of higher acenes is studied, in particular heptacene on Ag(001), starting from tetrahydroheptacene molecular precursors with and without additional functionalization by Br atoms. A variety of stable reaction intermediates is found, often resulting from hydrogen migration events. However, heptacene is the end-product from the two precursors and displays a fully charged LUMO orbital. Focusing on the intermediates, two sp3-hybridized carbon atoms present at the second ring of dihydroheptacene are shown as sufficient self-decoupling factors. Magnetic Kondo fingerprints associated to specific charging scenarios are investigated. Finally, the impact of the surface structure on coupling reactions with acene-based precursors is then explored. More specifically, Au(111) and Au(110) surfaces, as well as anthracene precursors functionalized with halogen and methyls are used with this aim. On Au(111), the atomically flat surface, five covalent coupling motifs are found, with the 3-fold symmetric starphene showing the highest occurrence upon annealing. In contrast, on Au(110), being a 2×1 reconstructed surface, the uniaxial symmetry of the surface promotes the formation of mainly linear non-benzenoid polymers along the grooves of this substrate.This thesis contributes to the surface science field by showing the possibility to synthesize a variety of novel carbon-based nanomaterials using on-surface synthesis methods. The second main contribution is the detailed characterization of the produced materials using surface-sensitive techniques assisted by theoretical calculations. A deep understanding of the physicochemical properties of these materials is a crucial step forward towards their ultimately progressing applications.CFM; CSI

Fragmenting markets and quality change in New Zealand foods: empirical analysis with a Rotterdam model

Very little is known about changes in the demand characteristics of food in New Zealand. As far as we can determine, there has never been a complete disaggregated food demand model estimated for New Zealand. The object of this paper is to update these estimates using more recent data to see whether there are grounds for believing that the structural changes that occurred primarily during the last two decades are having effects on the magnitude of food demand elasticities in New Zealand. To this end, a Rotterdam food demand system is estimated using time series data. The results indicate that over the last 20 years, household consumption has increased for fruit and vegetables, poultry, food eaten away from home, and sweet products, drinks and other foods. Fish, poultry, meat, farm products, cereals and meals away from home are all more price elastic than earlier estimates.consumer behaviour, food demand, agricultural and food policy, Rotterdam model, food quality, New Zealand, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis,

Freight Rates and Productivity Gains in British Tramp Shipping 1869-1950

The standard source for pre-WWII global freight rate trends is the Isserlis British tramp shipping index. We think it is flawed, and that its sources offer vastly more information than the Isserlis aggregate contains. The new data confirm the precipitous decline in nominal freight rates before the World War I, but it also extends the series to the 1940s. Furthermore, our new series is linked to the post-World War II era (documented by David Hummels), so that we can be more precise about what has happened over the very long run. We also create route-specific deflators by using the prices of commodities transported. Previous scholars have deflated their nominal freight rate indices by a price index that includes tradables not carried on all routes and non-tradables not carried on any route. Our deflated indices offer a more effective measure of the contribution of declining freight rates to commodity-price convergence across trading regions. Using the pricedual method and new indices for factor prices, we then calculate total factor productivity growth pre-war and interwar for five global routes. Finally, we identify the sources of the total factor productivity growth.

Layered Steered Space–Time-Spreading-Aided Generalized MC DS-CDMA

Abstract—We present a novel trifunctional multiple-input– multiple-output (MIMO) scheme that intrinsically amalgamates space–time spreading (STS) to achieve a diversity gain and a Vertical Bell Labs layered space–time (V-BLAST) scheme to attain a multiplexing gain in the context of generalized multicarrier direct-sequence code-division multiple access (MC DS-CDMA), as well as beamforming. Furthermore, the proposed system employs both time- and frequency-domain spreading to increase the number of users, which is also combined with a user-grouping technique to reduce the effects of multiuser interference