Anti-nuclear demonstration on Wall street

General note: Title and date provided by Bettye Lane.

Japan´s energy future: Between a return to nuclear energy and a turn to renewables

After the triple disaster of 11 March 2011, Japan is at an energy crossroad. In the short and medium run it depends on fossil fuel imports to ensure its energy security, but the long term will be determined by the decisions taken at present. For Japan energy security is a national security challenge, as stated in its National Security Strategy. The article reviews the Japanese nuclear path, studies the factors shaping the Japanese electricity market and analyzes the current energy situation. Moreover, it also assesses the principles that have marked Japan’s energy policy and the two last Strategic Energy Plans -one prior to Fukushima and the other after it- before tackling the debate on the optimal future energy mix that Japan should adopt to meet its energy security trilemma, marked by its environmental commitment.

Modelado detallado de una central nuclear CANDU con CITVAP.

La línea de cálculo de INVAP consiste principalmente de los códigos CONDOR y CITVAP. Este último es la versión mejorada del código CITATION II que resuelve la ecuación de difusión neutrónica multigrupo por el método de diferencias finitas. CITVAP es ampliamente usado para estudiar reactores de investigación y reactores de potencia tales como PWR, BWR, VVER y últimamente se implemento nuevas funciones para estudiar una central PHWR tipo Atucha. Siguiendo con la línea de reactores PHWR, en este trabajo se estudian las capacidades y deficiencias del código de núcleo CITVAP para modelar una central nuclear tipo CANDU. Se plantean mejoras a realizar para un manejo mas eficiente desde el punto de vista del usuario, tanto de la gestión de combustibles, movimientos de barras de control y zonas líquidas como mejoras en el modelo termohidraulico. La metodología consiste en validar la línea de cálculo de INVAP, contrastando los resultados con el benchmark IAEA-tecdoc-887. El proceso de validación consiste en cálculos de celda en dos y tres dimensiones usando los códigos CONDOR y SERPENT respectivamente, obtención de secciones eficaces macroscópicas en función del quemado y cálculos de núcleo para distintas configuraciones de los dispositivos de control usando un núcleo fresco y una distribución de quemado en equilibrio. Se analizan las dificultades que se presentan al modelar el núcleo con las capacidades actuales del código y se plantean posibles soluciones a implementar. Para un estudio completo de un reactor CANDU, se estudian tres de la características distintivas de este tipo de reactor: la termohidraulica, la gestión de combustibles y los dispositivos de control de reactividad, distribución de potencia y apagado.

Modelado detallado de una central nuclear CANDU con CITVAP.

La línea de cálculo de INVAP consiste principalmente de los códigos CONDOR y CITVAP. Este último es la versión mejorada del código CITATION II que resuelve la ecuación de difusión neutrónica multigrupo por el método de diferencias finitas. CITVAP es ampliamente usado para estudiar reactores de investigación y reactores de potencia tales como PWR, BWR, VVER y últimamente se implemento nuevas funciones para estudiar una central PHWR tipo Atucha. Siguiendo con la línea de reactores PHWR, en este trabajo se estudian las capacidades y deficiencias del código de núcleo CITVAP para modelar una central nuclear tipo CANDU. Se plantean mejoras a realizar para un manejo mas eficiente desde el punto de vista del usuario, tanto de la gestión de combustibles, movimientos de barras de control y zonas líquidas como mejoras en el modelo termohidraulico. La metodología consiste en validar la línea de cálculo de INVAP, contrastando los resultados con el benchmark IAEA-tecdoc-887. El proceso de validación consiste en cálculos de celda en dos y tres dimensiones usando los códigos CONDOR y SERPENT respectivamente, obtención de secciones eficaces macroscópicas en función del quemado y cálculos de núcleo para distintas configuraciones de los dispositivos de control usando un núcleo fresco y una distribución de quemado en equilibrio. Se analizan las dificultades que se presentan al modelar el núcleo con las capacidades actuales del código y se plantean posibles soluciones a implementar. Para un estudio completo de un reactor CANDU, se estudian tres de la características distintivas de este tipo de reactor: la termohidraulica, la gestión de combustibles y los dispositivos de control de reactividad, distribución de potencia y apagado.

Fuel let-down heat exchanger.

"Work performed under contract no. W-7405-Eng.-26."

Conceptual design of the integral measurement system of the radiation dose of the fuel elements for the ALFRED reactor.

Conceptual design of the integral measurement system of the radiation dose of the fuel elements for the ALFRED reactor.

Emergent Antiferromagnetism Out Of The Hidden-order" State In Uru2si2: High Magnetic Field Nuclear Magnetic Resonance To 40 T."

Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the hidden order (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

Observation Of D0 Meson Nuclear Modifications In Au+au Collisions At Sqrt[s(nn)] = 200 Gev.

We report the first measurement of charmed-hadron (D(0)) production via the hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N(bin), from p+p to central Au+Au collisions. The D(0) meson yields in central Au + Au collisions are strongly suppressed compared to those in p+p scaled by N(bin), for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p(T) is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

Espectroscopia de Ressonância Magnética Nuclear de 13C no estudo de rotas biossintéticas de produtos naturais

During the last five decades, as a result of an interaction between natural product chemistry, synthetic organic chemistry, molecular biology and spectroscopy, scientists reached an extraordinary level of comprehension about the natural processes by which living organisms build up complex molecules. In this context, 13C nuclear magnetic resonance spectroscopy, allied with isotopic labeling, played a determinant role. Nowadays, the widespread use of modern NMR techniques allows an even more detailed picture of the biochemical steps by accurate manipulation of the atomic nuclei. This article focuses on the development of such techniques and their impact on biosynthetic studies.

Nuclear and mitochondrial DNA markers in traceability of retail beef samples

Several characteristics are important in a traceability system of animal products, such as age at slaughter, breed composition, besides information of the productive chain. In general, the certification agent records information about the animals and the system which it came from, although cannot guarantee that the slaughtering, meat processing and distribution are error proof. Besides, there is a differential price, at least at the international market, based on sex and breed composition of the animals. Genetic markers allow identification of characteristics controlled in the beef cattle traceability program, as sex and breed composition, in order to correctly identify and appraise the final product for the consumer. The hypothesis of this study was that the majority beef samples retailed in the local market originate from female with a great participation of zebu breeds. Therefore, the objective of this work was to characterize retail beef samples with DNA markers that identify cattle sex and breed composition. Within 10 beef shops localized in Pirassununga, SP, Brazil, 61 samples were collected, all were genotyped as harboring Bos taurus mitochondrial DNA and 18 were positive for the Y chromosome amplification (male). For the marker sat1711b-Msp I the frequency of the allele A was 0.278 and for the marker Lhr-Hha I the frequency of the allele T was 0.417. The results of sat1711b-Msp I and Lhr-Hha I allelic frequencies are suggestive that the proportion of indicus genome compared with the taurine genome in the market meat is smaller than the observed in the Nellore breed. The procedure described in this study identified sex and subspecies characteristics of beef meat samples, with potential application in meat products certification in special as an auxiliary tool in beef cattle traceability programs.

Efeito do número da passagem e do gênero das células doadoras de núcleo no desenvolvimento de bovinos produzidos por transferência nuclear

Objetivou-se com este trabalho avaliar o efeito do número da passagem e do sexo das células doadoras de núcleo no desenvolvimento embrionário e fetal após transferência nuclear. Para isso, oócitos bovinos foram maturados, enucleados e reconstruídos com células somáticas de animal adulto. Após a fusão e ativação química, os zigotos reconstituídos foram cultivados em Charles Rosenkranz 2 (CR2) com monocamada de células da granulosa a 38,8ºC em atmosfera umidificada a 5% de CO2 em ar, durante sete dias, e transferidos para receptoras sincronizadas. As taxas de clivagem e desenvolvimento a blastocisto de embriões reconstruídos com células cultivadas por tempo maior foram inferiores às obtidas com os demais tempos de cultivo. Além disso, os blastocistos produzidos não resultaram no desenvolvimento de uma gestação a termo. Embora a taxa de clivagem em embriões fêmeas tenha sido maior, o número de embriões que atingiram o estádio de blastocisto foi maior nos embriões machos. No período gestacional, fêmeas apresentaram maior taxa de aborto entre 90 e 120 dias de gestação. Esses resultados indicam que células doadoras de núcleos cultivados por longos períodos dificultam a produção de blastocistos e aumentam as chances de perdas durante a gestação. Embriões clonados machos têm maior competência para se desenvolver a blastocisto e resultam em menor taxa de perda gestacional.

Memantine prevents cardiomyocytes nuclear size reduction in the left ventricle of rats exposed to cold stress

OBJECTIVES: Memantine is an N-methyl-d-aspartate (NMDA) glutamate receptor antagonist used to treat Alzheimer's disease. Previous studies have suggested that receptor blockers act as neuroprotective agents; however, no study has specifically investigated the impact that these drugs have on the heart. We sought to evaluate the effects of memantine on nuclear size reduction in cardiac cells exposed to cold stress. METHOD: We used male EPM-Wistar rats (n=40) divided into 4 groups: 1) Matched control (CON); 2) Memantine-treated rats (MEM); 3) Rats undergoing induced hypothermia (IH) and 4) Rats undergoing induced hypothermia that were also treated with memantine (IHM). Animals in the MEM and IHM groups were treated by oral gavage administration of 20 mg/kg/day memantine over an eight-day period. Animals in the IH and IHM groups were submitted to 4 hours of hypothermia in a controlled environment with a temperature of - 8ºC on the last day of the study. RESULTS: The MEM group had the largest cardiomyocyte nuclear size (151 ± 3.5 μm³ vs. CON: 142 ± 2.3 μm³; p<0.05), while the IH group had the smallest mean value of nuclear size. The nuclear size of the IHM group was preserved (125 ± 2.9 μm³) compared to the IH group (108 ± 1.7 μm³; p<0.05). CONCLUSION: Memantine prevented the nuclear size reduction of cardiomyocytes in rats exposed to cold stress.