Fast Computation of the Fitness Function for Protein Folding Prediction in a 2D Hydrophobic-Hydrophilic Model

Protein Folding Prediction (PFP) is essentially an energy minimization problem formalised by the definition of a fitness function. Several PFP models have been proposed including the Hydrophobic-Hydrophilic (HP) model, which is widely used as a test-bed for evaluating new algorithms. The calculation of the fitness is the major computational task in determining the native conformation of a protein in the HP model and this paper presents a new efficient search algorithm (ESA) for deriving the fitness value requiring only O(n) complexity in contrast to the full search approach, which takes O(n2). The improved efficiency of ESA is achieved by exploiting some intrinsic properties of the HP model, with a resulting reduction of more than 50% in the overall time complexity when compared with the previously reported Caching Approach, with the added benefit that the additional space complexity is linear instead of quadratic

A quantitative comparison of the cost of employing EOR-coupled CCS supplemented with secondary DSF storage for two large CO2 point sources

AbstractThis paper explores the impact of the temporally dynamic demand for CO2 for CCS-coupled EOR by evaluating the variable demand for new (i.e., non-recycled) anthropogenic CO2 within EOR projects and the extent to which EOR-coupled CCS is compatible with the need for baseload CO2 storage options for large anthropogenic point sources. A profile of CO2 demand over an assumed EOR project lifetime is applied across two different storage scenarios to illustrate the differences in cost associated with different EOR-coupled CCS configurations. The first scenario pairs a single EOR field with a DSF used to store any CO2 that is not used to increase oil recovery in the EOR field; the second scenario is designed to minimize storage in the DSF and maximize lower-cost EOR-based storage by bringing multiple EOR projects online over time as the previous project’s CO2 demand declines, making the source’s CO2 available for a subsequent project. Each scenario is evaluated for two facilities, emitting 3 and 6 MtCO2/y. Annual and lifetime average CO2 transport and storage costs are presented, and the impact of added capture and compression costs on overall project economics is examined.The research reported here suggests that the cost of implementing a CCS-coupled EOR project will be more than is typically assumed; in many cases a positive price on CO2 emitted to the atmosphere will be required to motivate deployment of these CO2-based EOR projects, except in the most idealized cases. The reasons for this conclusion are twofold. First, the costs of capitalizing, operating and monitoring a secondary DSF to provide backup storage for CO2 not demanded by the EOR operation can cut sharply into EOR revenues. Second, except in cases where a single firm figures both the CO2 source emissions and the associated EOR recovery on the same balance sheet, the oil production company is not likely to share a significant portion of revenues from the EOR field with the CO2 source. Thus, while EOR-coupled CCS may offer attractive early opportunities, these opportunities are likely only available to a small fraction of the CO2 source fleet in the U.S

‘C’était moi mais ce n’était pas moi’: portrayal of the disabled body in Catherine Breillat’s Abus de faiblesse (2013)

Writer/director Catherine Breillat’s most recent film, Abus de faiblesse (2013), explores an important moment of bodily transition: the change from able to disabled body. This semi-autobiographic film follows the story of film director Maud (Breillat’s alter ego), who forms a destructive relationship with a conman, Vilko, after she suffers a disabling stroke. This film shows consistency with Breillat’s previous work in its exploration of the constructed nature of the female body onscreen. In the past the filmmaker has portrayed moments of trauma and transition (such as childbirth, loss of virginity or rape) to subvert processes of objectification. The article argues that Abus de faiblesse challenges and subverts representation of the post-menopausal and disabled body onscreen. The film interrogates binary oppositions such as able/disabled and independence/dependency to challenge representations of the disabled body as ‘other’. With reference to scholarly work on disability and the ageing female body, the article suggests that Maud’s sadomasochistic relationship with Vilko is driven by a quest to retain her subjectivity after her stroke. The article demonstrates that the film dissects the feared and the unknown territory of the ageing female body

Cost-benefit analysis for commissioning decisions in GEO600

Gravitational wave interferometers are complex instruments, requiring years of commissioning to achieve the required sensitivities for the detection of gravitational waves, of order 10^-21 in dimensionless detector strain, in the tens of Hz to several kHz frequency band. Investigations carried out by the GEO600 detector characterisation group have shown that detector characterisation techniques are useful when planning for commissioning work. At the time of writing, GEO600 is the only large scale laser interferometer currently in operation running with a high duty factor, 70%, limited chiefly by the time spent commissioning the detector. The number of observable gravitational wave sources scales as the product of the volume of space to which the detector is sensitive and the observation time, so the goal of commissioning is to improve the detector sensitivity with the least possible detector down time. We demonstrate a method for increasing the number of sources observable by such a detector, by assessing the severity of non-astrophysical noise contaminations to efficiently guide commissioning. This method will be particularly useful in the early stages and during the initial science runs of the aLIGO and adVirgo detectors, as they are brought up to design performance.Comment: 17 pages, 17 figures, 2 table

A new species of stygobitic snail in the genus Antrorbis Hershler & Thompson, 1990 (Gastropoda, Cochliopidae) from the Appalachian Valley and Ridge of eastern Tennessee, USA

A new species of cave snail (Littorinimorpha: Cochliopidae) in the genus Antrorbis is described from the dark zone of two caves in the Appalachian Valley and Ridge province in eastern Tennessee, United States. The Tennessee Cavesnail, Antrorbis tennesseensis Perez, Shoobs, Gladstone, & Niemiller, sp. nov. is distinguished from its only known congener, Antrorbis breweri, by the absence of raised tubercles on its finely spirally striate protoconch, and its unique radular formula. Moreover, A. tennesseensis is genetically distinct from A. breweri based on substantial divergence at the mitochondrial CO1 locus. This is the first cavesnail to be described from the Appalachian Valley and Ridge (AVR) physiographic province in the state of Tennessee, which previously represented a substantial gap in the distribution of stygobitic (i.e., aquatic, subterranean-obligate) gastropods

Angular control of optical cavities in a radiation-pressure-dominated regime: the Enhanced LIGO case

We describe the angular sensing and control (ASC) of 4 km detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO). Enhanced LIGO, the culmination of the first generation LIGO detectors, operated between 2009 and 2010 with about 40 kW of laser power in the arm cavities. In this regime, radiation-pressure effects are significant and induce instabilities in the angular opto-mechanical transfer functions. Here we present and motivate the ASC design in this extreme case and present the results of its implementation in Enhanced LIGO. Highlights of the ASC performance are successful control of opto-mechanical torsional modes, relative mirror motions of ≤ 1×10^−7  rad rms, and limited impact on in-band strain sensitivity

GEO 600 and the GEO-HF upgrade program: successes and challenges

The German-British laser-interferometric gravitational wave detector GEO 600 is in its 14th year of operation since its first lock in 2001. After GEO 600 participated in science runs with other first-generation detectors, a program known as GEO-HF began in 2009. The goal was to improve the detector sensitivity at high frequencies, around 1 kHz and above, with technologically advanced yet minimally invasive upgrades. Simultaneously, the detector would record science quality data in between commissioning activities. As of early 2014, all of the planned upgrades have been carried out and sensitivity improvements of up to a factor of four at the high-frequency end of the observation band have been achieved. Besides science data collection, an experimental program is ongoing with the goal to further improve the sensitivity and evaluate future detector technologies. We summarize the results of the GEO-HF program to date and discuss its successes and challenges