Complexity and Inapproximability Results for Parallel Task Scheduling and Strip Packing

We study the Parallel Task Scheduling problem $Pm|size_j|C_{\max}$ with a constant number of machines. This problem is known to be strongly NP-complete for each $m \geq 5$, while it is solvable in pseudo-polynomial time for each $m \leq 3$. We give a positive answer to the long-standing open question whether this problem is strongly $NP$-complete for $m=4$. As a second result, we improve the lower bound of $\frac{12}{11}$ for approximating pseudo-polynomial Strip Packing to $\frac{5}{4}$. Since the best known approximation algorithm for this problem has a ratio of $\frac{4}{3} + \varepsilon$, this result narrows the gap between approximation ratio and inapproximability result by a significant step. Both results are proven by a reduction from the strongly $NP$-complete problem 3-Partition

New constraints on the free-streaming of warm dark matter from intermediate and small scale Lyman-α forest data

We present new measurements of the free-streaming of warm dark matter (WDM) from Lyman-α flux-power spectra. We use data from the medium resolution, intermediate redshift XQ-100 sample observed with the X-shooter spectrograph (z=3–4.2) and the high-resolution, high-redshift sample used in Viel et al. (2013) obtained with the HIRES/MIKE spectrographs (z=4.2 – 5.4 ). Based on further improved modelling of the dependence of the Lyman- α flux-power spectrum on the free-streaming of dark matter, cosmological parameters, as well as the thermal history of the intergalactic medium (IGM) with hydrodynamical simulations, we obtain the following limits, expressed as the equivalent mass of thermal relic WDM particles. The XQ-100 flux power spectrum alone gives a lower limit of 1.4 keV, the re-analysis of the HIRES/MIKE sample gives 4.1 keV while the combined analysis gives our best and significantly strengthened lower limit of 5.3 keV (all 2 σ C.L.). The further improvement in the joint analysis is partly due to the fact that the two data sets have different degeneracies between astrophysical and cosmological parameters that are broken when the data sets are combined, and more importantly on chosen priors on the thermal evolution. These results all assume that the temperature evolution of the IGM can be modeled as a power law in redshift. Allowing for a nonsmooth evolution of the temperature of the IGM with sudden temperature changes of up to 5000 K reduces the lower limit for the combined analysis to 3.5 keV. A WDM with smaller thermal relic masses would require, however, a sudden temperature jump of 5000 K or more in the narrow redshift interval z = 4.6 – 4.8 , in disagreement with observations of the thermal history based on high-resolution resolution Lyman- α forest data and expectations for photo-heating and cooling in the low density IGM at these redshifts.V. I. is supported by U.S. NSF Grant No. AST-1514734. V. I. also thanks M. McQuinn for useful discussions, and IAS, Princeton, for hospitality during his stay where part of this work was completed. M. V. and T. S. K. are supported by ERC-StG “cosmoIGM”. S. L. has been supported by FONDECYT grant number 1140838 and partially by PFB-06 CATA. V. D., M. V., S. C. acknowledge support from the PRIN INAF 2012 “The X-Shooter sample of 100 quasar spectra at z ∼ 3.5 : Digging into cosmology and galaxy evolution with quasar absorption lines. G. B. is supported by the NSF under award AST-1615814. S. L. E. acknowledges the receipt of an NSERC Discovery Grant. M. H. acknowledges support by ERC ADVANCED GRANT 320596 “The Emergence of Structure during the epoch of Reionization”. L. C. is supported by YDUN DFF 4090-00079. K. D. D. is supported by an NSF AAPF fellowship awarded under NSF grant AST-1302093. J. S. B. acknowledges the support of a Royal Society University Research Fellowship. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 189.A-0424. This work made use of the DiRAC High Performance Computing System (HPCS) and the COSMOS shared memory service at the University of Cambridge. These are operated on behalf of the STFC DiRAC HPC facility. This equipment is funded by BIS National E-infrastructure capital grant ST/J005673/1 and STFC grants ST/H008586/1, ST/K00333X/1

Hypothesis: Control of hepatic utilization of alanine by membrane transport or by cellular metabolism?

The rate of alanine transport into the liver limits its utilization even under the high alanine load resulting from a 90% casein diet, given that the rat has been adapted to that diet. A coordinated acceleration of alanine catabolism allows transport to remain ratelimiting. which in turn allows the adaptive regulation of transport to remain effective at high alanine loads. Accelerated degradation of alanine may change the hepatic amino acid content in a way that derepresses the activity of the alanine carrier system(s).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44189/1/10540_2005_Article_BF01140659.pd

Why is it difficult to implement e-health initiatives? A qualitative study

<b>Background</b> The use of information and communication technologies in healthcare is seen as essential for high quality and cost-effective healthcare. However, implementation of e-health initiatives has often been problematic, with many failing to demonstrate predicted benefits. This study aimed to explore and understand the experiences of implementers - the senior managers and other staff charged with implementing e-health initiatives and their assessment of factors which promote or inhibit the successful implementation, embedding, and integration of e-health initiatives.<p></p> <b>Methods</b> We used a case study methodology, using semi-structured interviews with implementers for data collection. Case studies were selected to provide a range of healthcare contexts (primary, secondary, community care), e-health initiatives, and degrees of normalization. The initiatives studied were Picture Archiving and Communication System (PACS) in secondary care, a Community Nurse Information System (CNIS) in community care, and Choose and Book (C&B) across the primary-secondary care interface. Implementers were selected to provide a range of seniority, including chief executive officers, middle managers, and staff with 'on the ground' experience. Interview data were analyzed using a framework derived from Normalization Process Theory (NPT).<p></p> <b>Results</b> Twenty-three interviews were completed across the three case studies. There were wide differences in experiences of implementation and embedding across these case studies; these differences were well explained by collective action components of NPT. New technology was most likely to 'normalize' where implementers perceived that it had a positive impact on interactions between professionals and patients and between different professional groups, and fit well with the organisational goals and skill sets of existing staff. However, where implementers perceived problems in one or more of these areas, they also perceived a lower level of normalization.<p></p> <b>Conclusions</b> Implementers had rich understandings of barriers and facilitators to successful implementation of e-health initiatives, and their views should continue to be sought in future research. NPT can be used to explain observed variations in implementation processes, and may be useful in drawing planners' attention to potential problems with a view to addressing them during implementation planning

Border Terriers under primary veterinary care in England: demography and disorders

The Border Terrier is a working terrier type that is generally considered to be a relatively healthy and hardy breed. This study aimed to characterise the demography and common disorders of Border Terriers receiving veterinary care in England using de-identified electronic patient record data within the VetCompass™ Programme

Source apportionment of ambient volatile organic compounds in major cities in Australia by positive matrix factorisation.

Source apportionment of the 6-daily, 24 h volatile organic compound (VOC) samples collected during 2003–2004 in Melbourne, Sydney and Brisbane was carried out using the Positive Matrix Factorisation software (PMF2). Fourteen C4-C10 VOCs were chosen for source apportionment. Biogenic emissions were not covered in this study because tracer VOCs such as isoprene were not measured. Five VOC source factors were identified, including the ‘evaporative / fuel distribution’ factor (contribute to 37% of the total mass of the 14 VOCs on average), the ‘vehicle exhaust / petrochemical industry’ factor (24%), the ‘biomass burning’ factor (13%), the ‘architectural surface coatings’ factor (5%) and the ‘other sources’ factor (14%). The relative contributions of the source factors to the ambient VOC concentration at the sampling sites were comparable to the relative emission loads of the local sources in Australian air emission inventories. The high contribution from evaporative emissions indicates that introduction of reduction measures for evaporative emissions could substantially reduce the VOC emissions in Australian cities. The total VOC mass and the contributions from vehicle related sources and biomass burning were higher in winter and autumn, while the contributions from surface coatings were higher in summer. © 2008, Clean Air Society of Australia and New Zealan

Opening a new window to other worlds with spectropolarimetry

A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of SEARCH include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, SEARCH will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 meters along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom