1,017 research outputs found

    The status of RNAi-based transgenic research in plant nematology

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    With the understanding of nematode-plant interactions at the molecular level, new avenues for engineering resistance have opened up, with RNA interference being one of them. Induction of RNAi by delivering double-stranded RNA (dsRNA) has been very successful in the model non-parasitic nematode, Caenorhabditis elegans, while in plant nematodes, dsRNA delivery has been accomplished by soaking nematodes with dsRNA solution mixed with synthetic neurostimulants. The success of in vitro RNAi of target genes has inspired the use of in planta delivery of dsRNA to feeding nematodes. The most convincing success of host-delivered RNAi has been achieved against root-knot nematodes. Plant-mediated RNAi has been shown to lead to the specific down-regulation of target genes in invading nematodes, which had a profound effect on nematode development. RNAi-based transgenics are advantageous as they do not produce any functional foreign proteins and target organisms in a sequence-specific manner. Although the development of RNAi-based transgenics against plant nematodes is still in the preliminary stage, they offer novel management strategy for the future

    The expression of heterologous Fe (III) phytosiderophore transporter HvYS1 in rice increases Fe uptake, translocation and seed loading and excludes heavy metals by selective Fe transport

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    Many metal transporters in plants are promiscuous, accommodating multiple divalent cations including some which are toxic to humans. Previous attempts to increase the iron (Fe) and zinc (Zn) content of rice endosperm by overexpressing different metal transporters have therefore led unintentionally to the accumulation of copper (Cu), manganese (Mn) and cadmium (Cd). Unlike other metal transporters, barley Yellow Stripe 1 (HvYS1) is specific for Fe. We investigated the mechanistic basis of this preference by constitutively expressing HvYS1 in rice under the control of the maize ubiquitin1 promoter and comparing the mobilization and loading of different metals. Plants expressing HvYS1 showed modest increases in Fe uptake, root-to-shoot translocation, seed accumulation and endosperm loading, but without any change in the uptake and root-to-shoot translocation of Zn, Mn or Cu, confirming the selective transport of Fe. The concentrations of Zn and Mn in the endosperm did not differ significantly between the wild-type and HvYS1 lines, but the transgenic endosperm contained significantly lower concentrations of Cu. Furthermore, the transgenic lines showed a significantly reduced Cd uptake, root-to-shoot translocation and accumulation in the seeds. The underlying mechanism of metal uptake and translocation reflects the down-regulation of promiscuous endogenous metal transporters revealing an internal feedback mechanism that limits seed loading with Fe. This promotes the preferential mobilization and loading of Fe, therefore displacing Cu and Cd in the seed.We acknowledge support from the European Research Council IDEAS Advanced Grant Program (BIOFORCE) to P.C., and the Spanish Ministry of Economy and Competitivity (MINECO; projects AGL2013-42175-R, co-financed with FEDER) and the Arag on Government (Group A03) to J.A. R.B was supported by a PhD fellowship from the University of Lleida, Spain

    An Instruction to Accelerate Software Caches

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    In this paper we propose an instruction to accelerate software caches. While DMAs are very efficient for predictable data sets that can be fetched before they are needed, they introduce a large latency overhead for computations with unpredictable access behavior. Software caches are advantageous when the data set is not predictable but exhibits locality. However, software caches also incur a large overhead. Because the main overhead is in the access function, we propose an instruction that replaces the look-up function of the software cache. This instruction is evaluated using the Multidimensional Software Cache and two multimedia kernels, GLCM and H.264 Motion Compensation. The results show that the proposed instruction accelerates the software cache access time by a factor of 2.6. This improvement translates to a 2.1 speedup for GLCM and 1.28 for MC, when compared with the IBM software cache

    Quaternary climate modulation of Pb isotopes in the deep Indian Ocean linked to the Himalayan chemical weathering

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    We use reductive sediment leaching to extract lead (Pb) from the authigenic fraction of marine sediments and reconstruct the Pb isotope evolution of the deep central Indian Ocean over the past 250 thousand years at ∼3 kyr resolution. Temporal variations define a binary mixing line that is consistent with data from ferromanganese nodules and which records mixing between two well-defined endmembers through time. The unradiogenic endmember appears to represent a widely-distributed Pb source, from mid-ocean ridges or possibly volcanic aerosols, while the radiogenic endmember coincides with the composition of Ganges–Brahmaputra river sediments that are indicative of the Himalayan weathering inputs. Glacial–interglacial Pb isotope variations are striking and can be explained by an enhancement of Himalayan contributions by two to three times during interglacial periods, indicating that climate modulates the supply of dissolved elements to the ocean. While these changes could accurately record variations in the continental chemical weathering flux in response to warmer and wetter conditions during interglacials, the relative proportions of Pb derived from the Ganges and Brahmaputra appear to have been constant through time. This observation may point towards particulate-dissolved interactions in the estuary or pro-delta as a buffer of short timescale variability in the composition (and potentially flux) of the fluvial inputs. In addition, the changes are recorded at 3800 m water depth, and with the lack of deep water formation in the Bay of Bengal, a mechanism to transfer such a signature into the deep ocean could either be reversible scavenging of dissolved Pb inputs and/or boundary exchange on the deep sea fan. Unless the mechanism transferring the Pb isotope signature into the deep ocean was itself highly sensitive to global climate cycles, and with the absence of a precessional signal in our Pb isotope data, we suggest that the Indian climate and its influence on basin-scale chemical weathering were strongly modulated by glacial versus interglacial boundary conditions

    The Functional Approach in Comparative Socio-Legal Research: Reflections Based on a Study of Plural Work Regulation in Australia and Indonesia

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    This article examines the potential use and limits of Zweigert and Kötz’ classical functional approach in comparative law for an empirical socio-legal research project. The project involves a comparison of the formal labour laws and informal norms and institutions which regulate restaurant work in the cities of Melbourne, Australia and Yogyakarta, Indonesia. The article argues that the functional approach is a necessary but incomplete method for overcoming the many issues of comparability between the two research sites; the method requires both extension of its analytical steps and explicit explanation of its limitations

    Iran: A Clash of Two Cultures?

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    Since the 1979 Revolution, the clerical regime in Iran has been limiting the legal profession’s autonomy by preventing members of the Iranian Bar Association (IBA) from freely electing their Board of Directors and by establishing a new body of lawyers—legal advisors of the judiciary—to contest the IBA’s professional monopoly. Clerics have even attempted to bring the legal profession under the control of the Ministry of Justice and merge it with the legal advisors. The IBA’s struggle to remain a civil society organisation independent of the judiciary offers a vantage point from which to explore the role of the legal profession in Iranian society and the legal system of the Islamic Republic. Why does the Iranian judiciary oppose an independent legal profession, and why does the profession refuse to capitulate? What are the implications of this ongoing conflict for the legal order of the Islamic Republic, whose political elite consists mainly of Islamic jurists? What are the socio-cultural consequences of undermining the integrity and autonomy of the legal profession? These questions will guide our inquiry.After discussing the IBA’s development before and after the 1979 Revolution, we describe how practising attorneys view the IBA, advocacy, legal practice, legal services and their troubled relationship with the judiciary. They recount the obstacles they encounter within a politicised judicial order and explain how they preserve professional integrity within a legal system that lacks the public’s confidence. We conclude by arguing that the Islamic Republic’s attempt to subordinate the legal profession to administrative and ideological control by the judiciary reflects the clash of two legal cultures. Iranian judges reconstruct and apply Islamic jurisprudence (fiqh) as part of their efforts to deliver substantive justice within a codified legal system, while IBA attorneys understand and seek to practise law consistent with the ideals of due process, certainty and uniformity in legal decision-making

    Solar PV fed non-isolated DC-DC converter for BLDC motor drive with speed control

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    Brushless DC motors (BLDC) are predominantly used these days due to its meritorious advantages over conventional motors. The paper presents PV fed BLDC speeds control system. A closed-loop interleaved boost converter increases the voltage from PV system to required level. Converter for BLDC operates at fundamental switching frequency which reduces losses due to high switching frequency. Internal current control method is developed and employed for the speed control of PV fed BLDC motor by sensing the actual speed feedback. Internal current controlled PV fed BLDC drive is analyzed with increamental speed with fixed torque and decreamental speed with fixed torque operating conditions. Also the system with speed control is verified for variable torque condition. The system is developed and results are developed using MATLAB/SIMULINK software.

    Mechanisms controlling the selective iron and zinc biofortification of rice

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    L’arròs es un cultiu bàsic, consumit per mes de 3 billons de persones. Es una font pobra en ferro (Fe) i zinc (Zn) per la qual cosa les poblacions pobres que depenen de l’arros per a la seva supervivència, sofreixen d’anèmia por deficiència de ferro (IDA) i zinc (ZnD). La desnutrició es un repte important, especialment en els països en desenvolupament on no hi ha les mesures nutritives comunes als països industrialitzats (una dieta variada, programes de fortificació i suplements dietètics). El bio-enriquiment mitjançant l’enginyeria genètica del contingut de Fe y Zn en arròs es una estratègia prometedora y pot resultar en un augmentant de les seves concentracions. Amb l’objectiu d’aconseguir arròs que acumuli nivells mes elevats de Fe y Zn he obtingut una població d’arròs transgènic mitjançant transformació combinatòria amb quatre gens implicats en l’absorció, transport, acumulació i biodisponibilitat d’aquestos dos minerals. Aquesta població combinatòria m’ha servit per a identificar els mecanismes antagònics i sinèrgics que son essencials per a controlar l’acumulació de Fe i Zn.El arroz es un cultivo básico para más de 3 billones de personas. El arroz es una fuente pobre de hierro (Fe) y zinc (Zn) por lo cual las poblaciones pobres que dependen del arroz para su supervivencia, sufren de anemia por deficiencia de hierro (IDA) y zinc (ZnD). La desnutrición es un reto importante, especialmente en los países en desarrollo donde están ausentes las medidas que son comunes en los países industrializados (dieta variada, programas de fortificación y suplementos dietéticos). El bio-enriquecimiento mediante la ingeniería genética del contenido de Fe y Zn en arroz es una estrategia prometedora para aumentar sus concentraciones. Con el objetivo de producir granos con más alto nivel de Fe y Zn he obtenido una población de arroz transgénico mediante transformación combinatoria con cuatro genes implicados en la absorción, transporte, acumulación y biodisponibilidad de estos dos minerales. Esta población combinatoria me sirvió para identificar los mecanismos antagónicos y sinérgicos que son esenciales para controlar la acumulación de Fe y Zn.Rice is staple crop for more than 3 billion people, since rice is poor source of iron (Fe) and zinc (Zn) world’s poorest people who depend on rice for their survival suffer from iron deficiency anaemia (IDA) and zinc deficiency (ZnD). Malnutrition is a significant challenge, particularly in the developing world where measures that are commonplace in industrialized countries (varied diet, fortification schemes, and dietary supplements) are largely absent. Biofortification of rice with Fe and Zn by genetic engineering is a promising strategy to increase Fe and Zn concentration. I established a combinatorial transgenic rice population by transformation with four genes involved in uptake, transport, accumulation and bioavailability of Fe and Zn, aiming to produce grains containing higher level of these two minerals. This combinatorial population helped to identify key antagonistic and synergistic mechanisms controlling Fe and Zn accumulation
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