539 research outputs found
Empirical models for grape vine leaf area estimation on cv. Trincadeira
Mestrado Vinifera Euromaster - Viticulture and Enology - Instituto Superior de Agronomia - UL / Institut National D'Etudes Superieures Agronomiques de MontpellierEstimating a Vineyard’s leaf area is of great importance when evaluating the productive and quality potential of a vineyard and for characterizing the light and thermal microenvironments of grapevine plants. The aim of the present work was to validate the Lopes and Pinto method for determining vineyard leaf area in the vineyards of Lisbon’s wine growing region in Portugal, with the typical local red grape cultivar Trincadeira, and to improve prediction quality by providing cultivar specific models. The presented models are based on independent datasets of two consecutive years 2015 and 2016. Fruiting shoots were collected and analyzed during all phenological stages. Primary leaf area of shoots is estimated by models using a calculated variable obtained from the average of the largest and smallest primary leaf area multiplied by the number of primary leaves, as presented by Lopes and Pinto (2005). Lateral Leaf area additionally uses the area of the biggest lateral leaf as predictor. Models based on Shoot length and shoot diameter and number of lateral leaves were tested as less laborious alternatives. Although very fast and easy to assess, models based on shoot length and diameter were not able to predict variability of lateral leaf area sufficiently and were susceptible to canopy management. The Lopes and Pinto method is able to explain a very high proportion of variability, both in primary and lateral leaf area, independently of the phenological stage, as well as before and after trimming. They are inexpensive, universal, practical, non-destructive methods which do not require specialized staff or expensive equipmentN/
Stochastic Games with Disjunctions of Multiple Objectives (Technical Report)
Stochastic games combine controllable and adversarial non-determinism with
stochastic behavior and are a common tool in control, verification and
synthesis of reactive systems facing uncertainty. Multi-objective stochastic
games are natural in situations where several - possibly conflicting -
performance criteria like time and energy consumption are relevant. Such
conjunctive combinations are the most studied multi-objective setting in the
literature. In this paper, we consider the dual disjunctive problem. More
concretely, we study turn-based stochastic two-player games on graphs where the
winning condition is to guarantee at least one reachability or safety objective
from a given set of alternatives. We present a fine-grained overview of
strategy and computational complexity of such \emph{disjunctive queries} (DQs)
and provide new lower and upper bounds for several variants of the problem,
significantly extending previous works. We also propose a novel value
iteration-style algorithm for approximating the set of Pareto optimal
thresholds for a given DQ.Comment: Technical report including appendix with detailed proofs, 29 page
The Proper Motion of the Central Compact Object RX J0822-4300 in the Supernova Remnant Puppis A
Using the High Resolution Camera (HRC) aboard the Chandra X-ray Observatory,
we have re-examined the proper motion of the central compact object RX
J0822-4300 in the supernova remnant Puppis A. New data from 2010 August,
combined with three archival data sets from as early as 1999 December, provide
a baseline of 3886 days (more than 10 1/2 years) to perform the measurement.
Correlating the four positions of RX J0822-4300 measured in each data set
implies a projected proper motion of mu 71 \pm 12 masy. For a distance of 2 kpc
this proper motion is equivalent to a recoil velocity of 672 \pm 115 km/s. The
position angle is found to be 244 \pm 11 degrees. Both the magnitude and
direction of the proper motion are in agreement with RX J0822-4300 originating
near the optical expansion center of the supernova remnant. For a displacement
of 371 \pm 31 arcsec between its birth place and today's position we deduce an
age of (5.2 \pm 1.0) 10^3 yrs for RX J0822-4300. The age inferred from the
neutron star proper motion and filament motions can be considered as two
independent measurements of the same quantity. They average to 4450 \pm 750 yrs
for the age of the supernova remnant Puppis A.Comment: Accepted for publication in the Astrophysical Journa
Prediction of time to prosthesis implantation as a function of joint anatomy in patients with developmental dysplasia of the hip
BACKGROUND:
Developmental dysplasia of the hip (DDH) can lead to pain and premature secondary osteoarthritis at an early stage. Joint-preserving osteotomy is an established solution to this problem. In contrast, a conservative approach would result in pain persistence, ultimately raising the patients question for a possible date of expected prosthesis implantation. The aim of the study was to identify the relationship between the dysplastic hip anatomy and the time of prosthesis implantation in order to enable prognostic predictions in younger patients with symptomatic DDH.
MATERIALS AND METHODS:
Data from 129 hips who received THA due to secondary DDH osteoarthritis were evaluated. The preoperative hip anatomy was evaluated for AI and LCE angle. Multiple linear regression analyses were then used to correlate the influence of these parameters with the patient's age at the time of surgery. In addition, a graphical relationship was derived by the method of power least squares curve fitting with second-degree polynomials.
RESULTS:
The mean age for THA was 54.3 ± 11 years. The time of surgery correlated significantly with LCE (0.37) and AI (- 0.3) (p < 0.001). The mean age of patients with LCE angle ≤ 10° was 41.9 ± 14.0 years, for LCE 11-20° 52.7 ± 9.5 years, and for LCE 21-30° 57.0 ± 10.3 years. The following formula could then be determined for the calculation of the potential patient age at the time of THA as a function of LCE angle: age pTHA = 40.2 + 0.8 × LCE angle - 0.01 × (LCE angle)2.
CONCLUSION:
A significant correlation between the extent of dysplasia and the time of prosthesis implantation was identified. In particular, the LCE and the AI correlated strongly with the time of implantation. The more dysplastic the angles were, the sooner the THA was necessary. Using the calculations presented in this study, the probable age of prosthesis implantation can be prognosticated and included in a counseling session about treatment options for DD
Certificates for Probabilistic Pushdown Automata via Optimistic Value Iteration
Probabilistic pushdown automata (pPDA) are a standard model for discrete
probabilistic programs with procedures and recursion. In pPDA, many
quantitative properties are characterized as least fixpoints of polynomial
equation systems. In this paper, we study the problem of certifying that these
quantities lie within certain bounds. To this end, we first characterize the
polynomial systems that admit easy-to-check certificates for validating bounds
on their least fixpoint. Second, we present a sound and complete Optimistic
Value Iteration algorithm for computing such certificates. Third, we show how
certificates for polynomial systems can be transferred to certificates for
various quantitative pPDA properties. Experiments demonstrate that our
algorithm computes succinct certificates for several intricate example programs
as well as stochastic context-free grammars with production rules.Comment: Full version of a paper to appear at TACAS 2023, 30 page
Complications of Resection Arthroplasty in Two-Stage Revision for the Treatment of Periprosthetic Hip Joint Infection
Little data is available regarding complications associated with resection arthroplasty in the treatment of hip periprosthetic joint infection (PJI). We assessed complications during and after two-stage revision using resection arthroplasty. In this retrospective study, 93 patients undergoing resection arthroplasty for hip PJI were included. Patients were assigned to a prosthesis-free interval of ≤10 weeks (group 1; 49 patients) or >10 weeks (group 2; 44 patients). The complication rates between groups were compared using the chi-squared test. The revision-free and infection-free survival was estimated using a Kaplan-Meier survival analysis. Seventy-one patients (76%) experienced at least one local complication (overall 146 complications). Common complications were blood loss during reimplantation (n = 25) or during explantation (n = 23), persistent infection (n = 16), leg length discrepancy (n = 13) and reinfection (n = 9). Patients in group 1 experienced less complications after reimplantation (p = 0.012). With increasing severity of acetabular bone defects, higher incidence of complications (p = 0.008), periprosthetic bone fractures (p = 0.05) and blood loss (p = 0.039) was observed. The infection-free survival rate at 24 months was 93.9% in group 1 and 85.9% in group 2. The indication for resection arthroplasty needs to be evaluated carefully, considering the high rate of complications and reduced mobility, particularly if longer prosthesis-free intervals are used
Proactive food waste prevention in grocery retail supply chains – an exploratory study
Purpose
Regarding the retail internal supply chain (SC), both retailers and research are currently focused on reactive food waste reduction options in stores (e.g. discounting or donations). These options reduce waste after a surplus has emerged but do not prevent an emerging surplus in the first place. This paper aims to reveal how retailers can proactively prevent waste along the SC and why the options identified are impactful but, at the same time, often complex to implement.
Design/methodology/approach
The authors follow an exploratory approach for a nascent topic to obtain insights into measures taken in practice. Interviews with experts from retail build the main data source.
Findings
The authors identify and analyze 21 inbound, warehousing, distribution and store-related options applied in grocery retail. Despite the expected high overall impact on waste, prevention measures in inbound logistics and distribution and warehousing have not been intensively applied to date.
Practical implications
The authors provide a structured approach to mitigate waste within retailers' operations and categorize the types of barriers that need to be addressed.
Originality/value
This research provides a better understanding of prevention options in retail operations, which has not yet been empirically explored. Furthermore, this study conceptualizes prevention and reduction options and reveals implementation patterns
Evaluating the fully automatic multi-language translation of the Swiss avalanche bulletin
The Swiss avalanche bulletin is produced twice a day in four languages. Due
to the lack of time available for manual translation, a fully automated
translation system is employed, based on a catalogue of predefined phrases and
predetermined rules of how these phrases can be combined to produce sentences.
The system is able to automatically translate such sentences from German into
the target languages French, Italian and English without subsequent
proofreading or correction. Our catalogue of phrases is limited to a small
sublanguage. The reduction of daily translation costs is expected to offset the
initial development costs within a few years. After being operational for two
winter seasons, we assess here the quality of the produced texts based on an
evaluation where participants rate real danger descriptions from both origins,
the catalogue of phrases versus the manually written and translated texts. With
a mean recognition rate of 55%, users can hardly distinguish between the two
types of texts, and give similar ratings with respect to their language
quality. Overall, the output from the catalogue system can be considered
virtually equivalent to a text written by avalanche forecasters and then
manually translated by professional translators. Furthermore, forecasters
declared that all relevant situations were captured by the system with
sufficient accuracy and within the limited time available
Coexistence in a One-Dimensional Cyclic Dominance Process
Cyclic (rock-paper-scissors-type) population models serve to mimic complex
species interactions. Focusing on a paradigmatic three-species model with
mutations in one dimension, we observe an interplay between equilibrium and
non-equilibrium processes in the stationary state. We exploit these insights to
obtain asymptotically exact descriptions of the emerging reactive steady state
in the regimes of high and low mutation rates. The results are compared to
stochastic lattice simulations. Our methods and findings are potentially
relevant for the spatio-temporal evolution of other non-equilibrium stochastic
processes.Comment: 4 pages, 4 figures and 2 pages of Supplementary Material. To appear
in Physical Review
Beeinflussung evozierter Potentiale nach passiver Fingerbewegung durch Variation der Reizparameter
Evozierte Potentiale stellen ein wichtiges Hilfsmittel für klinische und wissenschaftliche Untersuchungen in der Neurologie dar und erlauben je nach Methode eine unterschiedliche Aussage über entsprechende Funktionen des sensorischen Systems. Potentiale nach passiver Fingerbewegung, also propriozeptiv evozierte Potentiale wurden bislang in keiner Arbeit systematisch auf Ihre exakte Abhängigkeit von Bewegungsparametern untersucht. Dies beabsichtigt die vorliegende Arbeit und versucht mittels einer breiten Variation der Bewegungsparameter deren Auswirkungen auf zerebrale Potentiale zu klären. Mechanisch wurde dabei bei gesunden Probanden der Mittelfinger der rechten Hand repetitiv extendiert, wobei sich durch Variationen von Dauer, Amplitude und Geschwindigkeit acht verschiedene Stimulationsmodi ergaben. Simultan wurden elektroenzephalographisch die resultierenden elektrischen Potentialänderungen von der Kopfhaut abgeleitet und aufgezeichnet. Durch elektronische Mittelungsverfahren konnten die entstandenen evozierten Potentiale ausgewertet werden, indem zunächst einzelne Komponenten identifiziert wurden und anschließend deren Abhängigkeit von Bewegungsparametern untersucht wurde. Die Auswertung wurde sowohl auf Vorgänge nach Beginn als auch nach Ende der passiven Fingerbewegung bezogen.
Nach Beginn der Bewegung (Onset-Potentiale) traten im Bereich des sensorischen Kortex (P3-Fz) regelhaft die Komponenten P1 (durchschnittliche Latenz 44,55 ms, SD = 7,81 ms; durchschnittliche Amplitude 2,0 µV, SD 0,85µV) P2 (67 ms, SD = 10,2 ms; 2,8 µV, SD = 1,2 µV) und N1 (150 ms, SD = 11,4 ms; -1,78 µV, SD = 1,2 µV) auf.
Die Auswertung nach Abhängigkeit von Bewegungsparametern zeigte signifikant höhere Amplituden der initialen zweigipfeligen Positivierung (Komponenten P1 und P2) bei höherer Geschwindigkeit. Bezüglich Dauer und Amplitude der Bewegung konnte keine Abhängigkeit identifiziert werden.
Potentiale nach dem Ende einer passiven Fingerbewegung wurden in bislang keiner Arbeit beschrieben. Diese Offset-Potentiale können objektiv nur nach Bewegungen mit einer Länge von mindestens 150 ms untersucht werden und sind durch eine Negativierung 45 ms nach Ende der Bewegung mit zwei negativen Gipfeln bei 75 (N1)und 150 ms (N2) gekennzeichnet. Damit sind sie ähnlich wie die Potentiale nach Beginn der Bewegung zweigipfelig konfiguriert, jedoch entgegengesetzter Polarität. Es wurde eine Abhängigkeit der Offset-Potentiale von der Amplitude der vorhergehenden Bewegung gefunden.
Insbesondere die Potentiale nach dem Ende passiver Fingerbewegungen stellen ein noch weitgehend unerforschtes Gebiet wissenschaftlicher neurophysiologischer Untersuchungen dar und bedĂĽrfen daher weiterer Forschungsarbeit
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