Investigation of cryogenic mixed-refrigerant cooled current leads in combination with peltier elements

Current leads supply electrical energy from a room-temperature power supply to a superconducting application, representing thus a major thermal load. State-of-the-art cooling solutions use either open (vapor cooled) or multi-stage closed cycle systems. The multi-stage concept can be integrated in one cryogenic mixed refrigerant cycle (CMRC), where a wide-boiling fluid mixture absorbs the heat load continuously along the current lead. In this paper, we study the combination of CMRC cooling with Peltier elements at the warm end of DC current leads. The Peltier cooling may cause a temperature drop on the order of 80 K. This allows an optimization of the CMRC mixture composition towards lower temperatures, avoiding the use of high-boilers that risk to freeze out at low temperatures. Our studies suggest that Peltier and CMRC cooling can reduce the thermal load at the cold end by 30 to 45% compared to conventional conduction-cooled current leads

Merge over move and the Extended Projection Principle: MOM and the EPP Revisited

A class of proposals are examined that aim to avoid problems that arise in various instantiations of the ‘Merge over Move’ (MOM) cost-ofoperation distinction. It is concluded that while the mechanisms introduced there exhibit independently interesting features, they subtract substantially from the interest of the MOM economy of derivation explanations. The removal of an assumption will then be considered that makes the core cases involving there-constructions a problem to begin with: that non-finite T must host a specifier position (checking an EPP/D-feature). Denying the existence of such features removes the problem that the MOM distinction was introduced to solve, allowing the core cases of associate-movement vs. expletive-insertion to arise as a case of true optionality. Consequences for other phenomena are examined and the proposal is found to be consistent with much recent research investigating these phenomena.En este trabajo se examina una serie de propuestas destinadas a evitar problemas relacionados con varios casos de la distinción Ensamble sobre Movimiento (EsM) tomando como base el coste de la operación. Se concluye que mientras que los mecanismos introducidos en estas propuestas muestran rasgos que pueden ser interesantes de manera independiente, estos mismos se apartan sustancialmente del interés de las explicaciones derivacionales del marco EsM, basado en la economía. Será entonces cuando se considerará la eliminación de una asunción que convierta los casos básicos que implican construcciones-there en un problema con el que empezar: que el T no-finito ha de contener una posición de especificador (para cotejar un rasgo PPE/D). Negar la existencia de dichos rasgos elimina el problema para el que la distinción EsM se introdujo, permitiendo que los casos esenciales de movimiento del asociado frente a la inserción directa del expletivo se conviertan en un caso de verdadera opcionalidad. Se examinan consecuencias para otros fenómenos y se concluye que la propuesta es compatible con gran parte de las investigaciones recientes que estudian estos fenómenos.É analisada uma classe de propostas que procuram evitar problemas que emergem em v{rias instanciações da distinção de ‘Merge sobre Move’ (MOM). Conclui-se que, enquanto os mecanismos aí introduzidos exibem independentemente propriedades interessantes, eles subtraem substancialmente ao interesse das explicações da economia de derivação de MOM. A remoção de uma assunção será assim considerada, aquela que faz com que os casos centrais envolvendo construções com there constituam um problema: T não-finito deve abrigar uma posição Spec (satisfazendo uma propriedade do PPE/D). Negar a existência de tais propriedades remove o problema que a distinção MOM procurou resolver, permitindo aos casos centrais de movimento-associado vs inserção de expletivo emergir como um caso de verdadeira opcionalidade. São analisadas consequências para outros fenómenos e a proposta demonstra ser consistente com muita da investigação recente sobre os fenómenos

Glycine N-methyltransferases: A comparison of the crystal structures and kinetic properties of recombinant human, mouse and rat enzymes

Glycine N-methyltransferases (GNMTs) from three mammalian sources were compared with respect to their crystal structures and kinetic parameters. The crystal structure for the rat enzyme was published previously. Human and mouse GNMT were expressed in Escherichia coli in order to determine their crystal structures. Mouse GNMT was crystallized in two crystal forms, a monoclinic form and a tetragonal form. Comparison of the three structures reveals subtle differences, which may relate to the different kinetic properties of the enzymes. The flexible character of several loops surrounding the active site, along with an analysis of the active site boundaries, indicates that the observed conformations of human and mouse GNMTs are more open than that of the rat enzyme. There is an increase in kcat when going from rat to mouse to human, suggesting a correlation with the increased flexibility of some structural elements of the respective enzymes. © 2004 Wiley-Liss, Inc

History, background, concepts and current use of comedication and polypharmacy in psychiatry

Based on a careful literature search a review is presented of the history, background, concepts and current use of comedication and polypharmacy in psychiatry. The pros and cons of comedication and polypharmacy are presented, as well as their apparent increase in recent times. Possible reasons for the increase of comedication/polypharmacy are described. Both the potential advantages as well as the potential risks are discussed. The one sided view that all comedication/polypharmacy is nothing but problematic is questioned. Comedication/polypharmacy seems to be, among others, the current answer to the well-known limited efficacy and effectiveness of current monotherapy treatment strategies

Dynamic thermal simulation on retrofitting scenarios for semi-extensive sheep farms

Sheep and goat have a high adaptability to different climatic conditions. Nevertheless, even in extensive farming, these species benefit from the presence of structures that can mitigate stress from heat, cold and humidity changes. These shelters are used at night or for limited periods during the year. These are characterised by a low engineering and make extensive use of recycled material. Interesting innovation in rural areas could be represented by the re-development of these buildings in order to improve their internal microclimate. This work develops a thermal dynamic simulation model aimed at identifying the best solution to retrofit the envelope of existing livestock buildings. In this paper, three different solutions have been tested: insulation of vertical surfaces, insulation of roof and window type. Eight different materials have been considered for roof and vertical surfaces and four for the different kind of window glazing, analysing the building microclimate responses. As a reference building to compare the different solutions adopted has been chosen an extensive sheep farm located in the Italian Apennines. The results suggest that the best solution is to insulate the roof. The other elements offer negligible results in term of improving the internal microclimate conditions. For coating the roof it can also be considered a good response of all the analysed insulating materials, in order to increase the period of maintaining the temperature of comfort and not exceeding its critical values within the building

PCR-based detection of mobile genetic elements in total community DNA

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History-sensitive versus future-sensitive approaches to security in distributed systems

We consider the use of aspect-oriented techniques as a flexible way to deal with security policies in distributed systems. Recent work suggests to use aspects for analysing the future behaviour of programs and to make access control decisions based on this; this gives the flavour of dealing with information flow rather than mere access control. We show in this paper that it is beneficial to augment this approach with history-based components as is the traditional approach in reference monitor-based approaches to mandatory access control. Our developments are performed in an aspect-oriented coordination language aiming to describe the Bell-LaPadula policy as elegantly as possible. Furthermore, the resulting language has the capability of combining both history- and future-sensitive policies, providing even more flexibility and power.Comment: In Proceedings ICE 2010, arXiv:1010.530

Growth and glycemic control in children with type 1 diabetes and asymptomatic celiac disease treated with a gluten -free diet for 1 year

To compare growth and glycemic control in children with type 1 diabetes and silent celiac disease treated with a gluten-free diet for 1 year with those of similar age and gender with type 1 diabetes but without celiac disease, 16 type 1 diabetes patients with silent celiac disease were enrolled and each celiac disease-positive case was matched for age, sex, and duration of diabetes with two type 1 diabetes controls with negative serologic markers of celiac disease. All 16 children with positive celiac disease serology had histologic features consistent with celiac disease despite the absence of symptoms. The mean growth and metabolic control values were similar between children with type 1 diabetes and celiac disease and those with type 1 diabetes but without celiac disease. This study seems to suggest that the early diagnosis of celiac disease and initiation of a gluten-free diet may prevent further deterioration in the nutritional status of children with type 1 diabetes and celiac disease and may reduce the prospect of celiac disease complications without any impact on type 1 diabetes control