Effect of parallel magnetic field on the Zero Differential Resistance State

The non-linear zero-differential resistance state (ZDRS) that occurs for highly mobile two-dimensional electron systems in response to a dc bias in the presence of a strong magnetic field applied perpendicular to the electron plane is suppressed and disappears gradually as the magnetic field is tilted away from the perpendicular at fixed filling factor $\nu$. Good agreement is found with a model that considers the effect of the Zeeman splitting of Landau levels enhanced by the in-plane component of the magnetic field.Comment: 4 pages, 4 figure

Comparison of System Call Representations for Intrusion Detection

Over the years, artificial neural networks have been applied successfully in many areas including IT security. Yet, neural networks can only process continuous input data. This is particularly challenging for security-related non-continuous data like system calls. This work focuses on four different options to preprocess sequences of system calls so that they can be processed by neural networks. These input options are based on one-hot encoding and learning word2vec or GloVe representations of system calls. As an additional option, we analyze if the mapping of system calls to their respective kernel modules is an adequate generalization step for (a) replacing system calls or (b) enhancing system call data with additional information regarding their context. However, when performing such preprocessing steps it is important to ensure that no relevant information is lost during the process. The overall objective of system call based intrusion detection is to categorize sequences of system calls as benign or malicious behavior. Therefore, this scenario is used to evaluate the different input options as a classification task. The results show, that each of the four different methods is a valid option when preprocessing input data, but the use of kernel modules only is not recommended because too much information is being lost during the mapping process.Comment: 12 pages, 1 figure, submitted to CISIS 201

A simple and robust method for connecting small-molecule drugs using gene-expression signatures

Interaction of a drug or chemical with a biological system can result in a gene-expression profile or signature characteristic of the event. Using a suitably robust algorithm these signatures can potentially be used to connect molecules with similar pharmacological or toxicological properties. The Connectivity Map was a novel concept and innovative tool first introduced by Lamb et al to connect small molecules, genes, and diseases using genomic signatures [Lamb et al (2006), Science 313, 1929-1935]. However, the Connectivity Map had some limitations, particularly there was no effective safeguard against false connections if the observed connections were considered on an individual-by-individual basis. Further when several connections to the same small-molecule compound were viewed as a set, the implicit null hypothesis tested was not the most relevant one for the discovery of real connections. Here we propose a simple and robust method for constructing the reference gene-expression profiles and a new connection scoring scheme, which importantly allows the valuation of statistical significance of all the connections observed. We tested the new method with the two example gene-signatures (HDAC inhibitors and Estrogens) used by Lamb et al and also a new gene signature of immunosuppressive drugs. Our testing with this new method shows that it achieves a higher level of specificity and sensitivity than the original method. For example, our method successfully identified raloxifene and tamoxifen as having significant anti-estrogen effects, while Lamb et al's Connectivity Map failed to identify these. With these properties our new method has potential use in drug development for the recognition of pharmacological and toxicological properties in new drug candidates.Comment: 8 pages, 2 figures, and 2 tables; supplementary data supplied as a ZIP fil

Risk factors associated with lambing traits

peer-reviewedThis article was first published in Animal (2016), 10:1, pp 89–95, © The Animal Consortium 2015The objective of this study was to establish the risk factors associated with both lambing difficulty and lamb mortality in the Irish sheep multibreed population. A total of 135 470 lambing events from 42 675 ewes in 839 Irish crossbred and purebred flocks were available. Risk factors associated with producer-scored ewe lambing difficulty score (scale of one (no difficulty) to four (severe difficulty)) were determined using linear mixed models. Risk factors associated with the logit of the probability of lamb mortality at birth (i.e. binary trait) were determined using generalised estimating equations. For each dependent variable, a series of simple regression models were developed as well as a multiple regression model. In the simple regression models, greater lambing difficulty was associated with quadruplet bearing, younger ewes, of terminal breed origin, lambing in February; for example, first parity ewes experienced greater (P7.0 kg) birth weights, quadruplet born lambs and lambs that experienced a more difficult lambing (predicted probability of death for lambs that required severe and veterinary assistance of 0.15 and 0.32, respectively); lambs from dual-purpose breeds and born to younger ewes were also at greater risk of mortality. In the multiple regression model, the association between ewe parity, age at first lambing, year of lambing and lamb mortality no longer persisted. The trend in solutions of the levels of each fixed effect that remained associated with lamb mortality in the multiple regression model, did not differ from the trends observed in the simple regression models although the differential in relative risk between the different lambing difficulty scores was greater in the multiple regression model. Results from this study show that many common flock- and animal-level factors are associated with both lambing difficulty and lamb mortality and management of different risk category groups (e.g. scanned litter sizes, ewe age groups) can be used to appropriately manage the flock at lambing to reduce their incidence

Day surgery in a teaching hospital: identifying barriers to productivity.

Introduction: Ambulatory surgery is a standard of care for many surgical procedures due to cost-effectiveness and benefits to patients including the reduced risk of contracting hospital infection by reducing the hospital stay. However, late cancellations can be costly. We examined the utilisation of the surgical day ward in our institution over a four-year period. Methods: A retrospective study of surgical day ward records from September 2007 to September 2011 in one institution. Parameters investigated included the number of planned admissions. Reasons for cancellations were also collected. Results: A total of 17,461 procedures were intended as a day ward admission during the study interval. There were 3,539 procedures that were cancelled (20.3%). The prevalent proportion of cancellations (n = 1,367) (38.6%) were due to patients not showing up for their procedures (7.8% of planned admissions); 1,188 (33.6%) patients were cancelled by the admissions office due to bed shortages, accounting for 6.8 % of planned admissions and 650 (18.4%) of cases were due to last minute cancellations by patients, accounting for 3.7% of all planned admission. The remaining 334 (9.4%) of cases were cancelled on medical grounds including patients who were considered unfit for the intended procedure, or anti-coagulations not appropriately ceased prior to surgery, accounting for 1.9% of all planned admissions. Conclusion: The cancellation rate in this study was high, mainly due to failure of patients to attend or signal their intentions, inadequate bed capacity and bed closure strategies. The ring fencing and protection of day beds and a more active patient management interaction would have had the greatest impact on increased efficiency

Response of carbon fluxes to water relations in a savanna ecosystem in South Africa

International audienceThe principal mechanisms that connect carbon fluxes with water relations in savanna ecosystems were studied by using eddy covariance in a savanna ecosystem at Kruger National Park, South Africa. Since the annual drought and rewetting cycle is a major factor influencing the function of savanna ecosystems, this work focused on the close inter-connection between water relations and carbon fluxes. Data from a nine-month measuring campaign lasting from the early wet season to the late dry season were used. Total ecosystem respiration showed highest values at the onset of the growing season, a slightly lower plateau during the main part of the growing season and a continuous decrease during the transition towards the dry season. The regulation of canopy conductance was changed in two ways: changes due to phenology during the course of the growing season and short-term acclimation to soil water conditions. The most constant parameter was water use efficiency that was influenced by VPD during the day but the VPD response curve of water usage did change only slightly during the course of the growing season and decreased by about 30% during the transition from wet to dry season. The regulation of canopy conductance and photosynthetic capacity were closely related. This observation meets recent leaf-level findings that stomatal closure triggers down-regulation of Rubisco during drought. Our results may show the effects of these processes on the ecosystem scale

Propagation of Avalanches in Mn12_{12}-acetate: Magnetic Deflagration

Local time-resolved measurements of fast reversal of the magnetization of single crystals of Mn12-acetate indicate that the magnetization avalanche spreads as a narrow interface that propagates through the crystal at a constant velocity that is roughly two orders of magnitude smaller than the speed of sound. We argue that this phenomenon is closely analogous to the propagation of a flame front (deflagration) through a flammable chemical substance.Comment: 5 pages, 5 figure

Evaluating the Impact of a New Interactive Digital Solution for Collecting Care Quality In-formation for Residential Homes

Collecting and analysing timely and accurate information about the quality of care that is delivered to older people in residential homes is a challenge. Most current approaches to collecting this in-formation are manual, and add time, cost and human error to them. Interactive digital technologies have the potential to reduce the time consumed, cost and errors in these processes, which in turn can support resolution of an important social challenge. However, designing these interactions can be problematic. In this paper we report the use of a new interactive digital solution that was de-signed to improve the completeness and timeliness of care quality data that was collected from 233 residential nursing and care homes for older people in and around London. Use of the digital solution led to a significant increase in the numbers of residential homes that submitted the cor-rect care quality information by each quarterly deadline. However, qualitative evidence from the residential homes revealed low-level usability problems experienced by care staff that might be in-dicative of continuing usability issues in the care sector. The paper ends with lessons drawn to improve uptake of digital technologies in residential care