310 research outputs found
Performance and diarrhoea in piglets following weaning at seven weeks of age: Challenge with E. coli O 149 and effect of dietary factors
Four dietary factors (ad libitum versus feed restriction, control versus protein restriction at ad libitum feeding, control versus inclusion of lupine as a protein source at ad libitum feeding, and control versus extra vitamin E at ad libitum feeding) were tested in four separate experiments for the effect on diarrhoea. To introduce a diarrhoea-like condition, half of the piglets were challenged with an inoculation of an E. coli O 149 dose of 1 x 108 colony forming units on day two and three after weaning (day of weaning = day one). All piglets were susceptible since the dams were tested mono-zygotic susceptible to the attachment site of E. coli O 149 in the intestines. Each of the four experiments included 32 piglets from 4 sows. The design was 2 x 2 factorial with dietary factor and E. coli O 149 challenge as the two factors, each at two levels. The piglets were housed individually during the experiment which lasted for 10 days from weaning at 7 weeks of age. The daily recordings included feed intake, weight and faeces score (from 1 = firm and solid to 6 = yellow and watery). Faeces from days 2 to 5 were tested for E. coli strains. In addition, blood was sampled and serum was analysed for E. coli antibodies, IgG and IgM. Generally the E. coli challenge had no effect on growth and feed intake whereas faeces score and number of faeces haemolytic bacteria increased and faeces dry matter decreased. Feed restriction decreased the weight gain while faeces characteristics were unaffected. An analysis including all four experiments revealed that a feed intake of less than 200 g day one after weaning seems to be associated with a relatively high incidence of a post-weaning diarrhoea-like condition. Protein restriction decreased faeces score and increased faeces dry matter while weight gain tended to decrease. Inclusion of lupine affected neither weight gain nor faeces characteristics. Extra vitamin E did not affect weight gain while faeces dry matter decreased, and faeces score and number of faecal haemolytic bacteria increased. The dietary treatments had no effect on the immunological responses. In conclusion, the studied dietary factors could not alleviate a diarrhoea-like condition and at the same time maintain the growth rate. Furthermore, the results indicate that performance can be improved if piglets achieve a daily feed intake of at least 200 g from day one after weaning
AES-Based Authenticated Encryption Modes in Parallel High-Performance Software
Authenticated encryption (AE) has recently gained renewed interest due to the ongoing CAESAR competition. This paper deals with the performance of block cipher modes of operation for AE in parallel software. We consider the example of the AES on Intel\u27s new Haswell microarchitecture that has improved instructions for AES and finite field multiplication.
As opposed to most previous high-performance software implementations of operation modes -- that have considered the encryption of single messages -- we propose to process multiple messages in parallel. We demonstrate that this message scheduling is of significant advantage for most modes. As a baseline for longer messages, the performance of AES-CBC encryption on a single core increases by factor 6.8 when adopting this approach.
For the first time, we report optimized AES-NI implementations of the novel AE modes OTR, CLOC, COBRA, SILC, McOE-G, POET and Julius -- both with single and multiple messages. For almost all AE modes considered, we obtain a consistent speed-up when processing multiple messages in parallel. Notably, among the nonce-based modes, CCM, CLOC and SILC get by factor 3.7 faster, achieving a performance comparable to GCM (the latter, however, possessing classes of weak keys), with OCB3 still performing at only 0.77 cpb. Among the nonce-misuse resistant modes, McOE-G receives a speed-up by more than factor 4 with a performance of about 1.62 cpb, with COPA consistently performing best at 1.45 cpb
The Online Patient Satisfaction Index for Patients With Low Back Pain:Development, Reliability, and Validation Study
BACKGROUND: Low back pain is highly prevalent, and most often, a specific causative factor cannot be identified. Therefore, for most patients, their low back pain is labeled as nonspecific. Patient education and information are recommended for all these patients. The internet is an accessible source of medical information on low back pain. Approximately 50% of patients with low back pain search the internet for health and medical advice. Patient satisfaction with education and information is important in relation to patients’ levels of inclination to use web-based information and their trust in the information they find. Although patients who are satisfied with the information they retrieve use the internet as a supplementary source of information, dissatisfied patients tend to avoid using the internet. Consumers’ loyalty to a product is often applied to evaluate their satisfaction. Consumers have been shown to be good ambassadors for a service when they are willing to recommend the service to a friend or colleague. When consumers are willing to recommend a service to a friend or colleague, they are also likely to be future users of the service. To the best of our knowledge, no multi-item instrument exists to specifically evaluate satisfaction with information delivered on the web for people with low back pain. OBJECTIVE: This study aims to report on the development, reliability testing, and construct validity testing of the Online Patient Satisfaction Index to measure patients’ satisfaction with web-based information for low back pain. METHODS: This is a cross-sectional validation study of the Online Patient Satisfaction Index. The index was developed with experts and assessed for face validity. It was subsequently administered to 150 adults with nonspecific low back pain. Of these, 46% (70/150) were randomly assigned to participate in a reliability test using an intraclass correlation coefficient of agreement. Construct validity was evaluated by hypothesis testing based on a web app (MyBack) and Wikipedia on low back pain. RESULTS: The index includes 8 items. The median score (range 0-24) based on the MyBack website was 20 (IQR 18-22), and the median score for Wikipedia was 12 (IQR 8-15). The entire score range was used. Overall, 53 participants completed a retest, of which 39 (74%) were stable in their satisfaction with the home page and were included in the analysis for reliability. Intraclass correlation coefficient of agreement was estimated to be 0.82 (95% CI 0.68-0.90). Two hypothesized correlations for construct validity were confirmed through an analysis using complete data. CONCLUSIONS: The index had good face validity, excellent reliability, and good construct validity and can be used to measure satisfaction with the provision of web-based information regarding nonspecific low back pain among people willing to access the internet to obtain health information. TRIAL REGISTRATION: ClinicalTrials.gov NCT03449004; https://clinicaltrials.gov/ct2/show/NCT0344900
Haraka v2 – Efficient Short-Input Hashing for Post-Quantum Applications
Recently, many efficient cryptographic hash function design strategies have been explored, not least because of the SHA-3 competition. These designs are, almost exclusively, geared towards high performance on long inputs. However, various applications exist where the performance on short (fixed length) inputs matters more. Such hash functions are the bottleneck in hash-based signature schemes like SPHINCS or XMSS, which is currently under standardization. Secure functions specifically designed for such applications are scarce. We attend to this gap by proposing two short-input hash functions (or rather simply compression functions). By utilizing AES instructions on modern CPUs, our proposals are the fastest on such platforms, reaching throughputs below one cycle per hashed byte even for short inputs, while still having a very low latency of less than 60 cycles. Under the hood, this results comes with several innovations. First, we study whether the number of rounds for our hash functions can be reduced, if only second-preimage resistance (and not collision resistance) is required. The conclusion is: only a little. Second, since their inception, AES-like designs allow for supportive security arguments by means of counting and bounding the number of active S-boxes. However, this ignores powerful attack vectors using truncated differentials, including the powerful rebound attacks. We develop a general tool-based method to include arguments against attack vectors using truncated differentials
Bimodality and alternative equilibria do not help explain long-term patterns in shallow lake chlorophyll-a
Since its inception, the theory of alternative equilibria in shallow lakes has
evolved and been applied to an ever wider range of ecological and socioecological
systems. The theory posits the existence of two alternative stable
states or equilibria, which in shallow lakes are characterised by either clear
water with abundant plants or turbid water where phytoplankton dominate.
Here, we used data simulations and real-world data sets from Denmark and
north-eastern USA (902 lakes in total) to examine the relationship between
shallow lake phytoplankton biomass (chlorophyll-a) and nutrient concentrations
across a range of timescales. The data simulations demonstrated that
three diagnostic tests could reliably identify the presence or absence of
alternative equilibria. The real-world data accorded with data simulations
where alternative equilibria were absent. Crucially, it was only as the temporal
scale of observation increased (>3 years) that a predictable linear relationship
between nutrient concentration and chlorophyll-a was evident. Thus, when a
longer term perspective is taken, the notion of alternative equilibria is not
required to explain the response of chlorophyll-a to nutrient enrichment
which questions the utility of the theory for explaining shallow lake response
to, and recovery from, eutrophication.C.D.S. and T.A.D. would like to thank June and Derek Sayer for extraordinary
support over many years. The authors of this work have been
supported by a number of projects over the elephantine gestation period
of this manuscript. These include support from the Poul Due Jensen
Fonden, Danmarks Frie Forskningsfond Natur og Univers project
GREENLAKES (No. 9040-00195B) and the UFM-funded project LTER_DK
for Long Term Ecosystem Research in Denmark. In addition, support was
provided by The European Union’s Horizon 2020 research and innovation
programmes under grant agreement No 869296—The PONDERFUL
Project”, TREICLAKE under grant agreement No 951963, and the
AQUACOSM project and by the European Commission EU H2020-
INFRAIA-project (No. 731065) and AQUACOSMplus (No. 871081). E.J. was
also supported by the TĂśBITAK outstanding researcher programme2232
(project 118C250) and AnaEE, Denmark. The work of D.G. was funded by
the Fourth Period of Programme-oriented Funding, Helmholtz Association
of German ResearchCentres, Research Field Earth and Environment.C.D.S. and T.A.D. would like to thank June and Derek Sayer for extraordinary
support over many years. The authors of this work have been
supported by a number of projects over the elephantine gestation period
of this manuscript. These include support from the Poul Due Jensen
Fonden, Danmarks Frie Forskningsfond Natur og Univers project
GREENLAKES (No. 9040-00195B) and the UFM-funded project LTER_DK
for Long Term Ecosystem Research in Denmark. In addition, support was
provided by The European Union’s Horizon 2020 research and innovation
programmes under grant agreement No 869296—The PONDERFUL
Project”, TREICLAKE under grant agreement No 951963, and the
AQUACOSM project and by the European Commission EU H2020-
INFRAIA-project (No. 731065) and AQUACOSMplus (No. 871081). E.J. was
also supported by the TĂśBITAK outstanding researcher programme2232
(project 118C250) and AnaEE, Denmark. The work of D.G. was funded by
the Fourth Period of Programme-oriented Funding, Helmholtz Association
of German ResearchCentres, Research Field Earth and Environment
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