3,319 research outputs found
Characterization of packaging ability to protect beer from light degradation and introduction of a new Packaging Riboflavin Index
Bottled beer is exposed to light during transport or storage, which can unfavourably affect its sensory properties. One of the functions of the packaging is to provide maximum protection against possible light degradation. Riboflavin (vitamin B2), which acts as a photosensitizer, is a key substance for the occurrence of light degradation in beer. Riboflavin absorbs light in the visible region of the spectrum and transfers its energy to other compounds. A cascade of subsequent chemical reactions leads to sensory damage to the beer. Based on the transmission spectrum of packaging (glass and plastic), the Packaging Riboflavin Index (PRFI)was introduced. PRFI was designed as a tool which quantitatively assesses the ability of packaging to protect beer from light damage. The basic types of commercially used glass and plastic packaging were compared using this index. The validity of the index was verified in an experiment with defined light damage of beer in different packaging
Using travel times for optimization numbers of medical rescue service points—case study from Slovakia
Health care and protection is one of the fundamental human rights, which apply to all people of the world. Life and health threats can occur at any place and time, both at times of peace and security and at times of emergencies of any kind. In many cases, provision of urgent medical care creates a time strain. Emergency medical care in the Slovak Republic is provided by a medical rescue service, including mobile emergency care and ambulances, with or without a doctor. The present article deals with the purpose and role of medical rescue service with an emphasis on mobile emergency care provision by ambulances. The following part defines selected factors affecting medical rescue service station locations and numbers of ambulances. Emphasis is laid on an analysis of theoretical assumptions for optimization of the number of medical rescue service stations and ambulances used by them for the purpose of securing care of life and health of the population and addressing emergencies within selected territorial units in the Self‐Governing Region of Žilina. The proposed optimization of the number of medical rescue service stations in municipalities is addressed theoretically as a location issue. The resulting theoretical variant of the proposed new distribution of medical rescue service ambulance stations is a mathematical consideration of assurance of emergency medical care provision within 15 min from each event reporting. The mathematical algorithm used for the proposal of medical rescue service ambulance station distribution is appli-cable in different regions and countries with a defined time to provision of first aid and emergency medical care. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.[VI04000080]; [RVO/FLKR/2020/03]; [IGA/FLKR/2019/001]; [KEGA 012TUKE-4/2019]; [APVV SK-SRB-18-0053]Kultúrna a Edukacná Grantová Agentúra MŠVVaŠ SR, KEGA: 4/201
Non-Pareto Optimality of MPTCP: Performance Issues and a Possible Solution
MPTCP has been proposed as a mechanism to support transparently multiple connections to the application layer and is under discussion at the IETF. It can use effectively the available bandwidth and it improves throughput and fairness, compared to independent TCP flows in many scenarios. However we show, by measurements over our testbed and analytically, that MPTCP still suffers from two problems: (P1) upgrading some TCP users to MPTCP can reduce the throughput of others without any benefit to the upgraded users, which is a symptom of non-Pareto optimality; (P2) MPTCP users could be excessively aggressive towards TCPusers. We attribute these problems to the “Linked Increases”Algorithm(LIA) of MPTCP, and more specifically, to an excessive amount of traffic transmitted over congested paths. The design of LIA forces a tradeoff between optimal resource pooling and responsiveness. Hence, to provide good responsiveness MPTCP’s current implementation must depart from Pareto-optimality. We revisit the problem and show that it is possible to simultaneously provide these two properties. We implement the resulting algorithm, called Opportunistic “Linked Increases” Algorithm (OLIA), in the Linux kernel and study its performance over our testbed by simulations and by theoretical analysis. We prove that OLIA is Pareto-optimal, hence avoids the problems (P1) and (P2). Our mea- surements and simulations indicate that MPTCP with OLIA is as responsive and non-flappy as MPTCP with LIA, while solving problems (P1) and (P2)
Root-zone soil moisture variability across African savannas : From pulsed rainfall to land‐cover switches
The main source of soil moisture variability in savanna ecosystems is pulsed rainfall. Rainfall pulsing impacts water-stress durations, soil moisture switching between wet-to-dry and dry-to-wet states, and soil moisture spectra as well as derived measures from it such as soil moisture memory. Rainfall pulsing is also responsible for rapid changes in grassland leaf area and concomitant changes in evapotranspirational (ET) losses, which then impact soil moisture variability. With the use of a hierarchy of models and soil moisture measurements, temporal variability in root-zone soil moisture and water-stress periods are analysed at four African sites ranging from grass to miombo savannas. The normalized difference vegetation index (NDVI) and potential ET (PET)-adjusted ET model predict memory timescale and dry persistence in agreement with measurements. The model comparisons demonstrate that dry persistence and mean annual dry periods must account for seasonal and interannual changes in maximum ET represented by NDVI and to a lesser extent PET. Interestingly, the precipitation intensity and soil moisture memory were linearly related across three savannas with ET/infiltration similar to 1.0. This relation and the variability of length and timing of dry periods are also discussed.Peer reviewe
The effect of rainfall amount and timing on annual transpiration in a grazed savanna grassland
The role of precipitation (P) variability with respect to evapotranspiration (ET) and its two components, transpiration (T) and evaporation (E), from savannas continues to draw significant research interest given its relevance to a number of ecohydrological applications. Our study reports on 6 years of measured ET and estimated T and E from a grazed savanna grassland at Welgegund, South Africa. Annual P varied significantly with respect to amount (508 to 672 mm yr(-1)), with dry years characterized by infrequent early-season rainfall. T was determined using annual water-use efficiency and gross primary production estimates derived from eddy-covariance measurements of latent heat flux and net ecosystem CO2 exchange rates. The computed annual T for the 4 wet years with frequent early wet-season rainfall was nearly constant, 326 +/- 19 mm yr(-1) (T/ET=0.51), but was lower and more variable between the 2 dry years (255 and 154 mm yr(-1), respectively). Annual T and T/ET were linearly related to the early wet-season storm frequency. The constancy of annual T during wet years is explained by the moderate water stress of C4 grasses as well as trees' ability to use water from deeper layers. During extreme drought, grasses respond to water availability with a dieback-regrowth pattern, reducing leaf area and transpiration and, thus, increasing the proportion of transpiration contributed by trees. The works suggest that the early-season P distribution explains the interannual variability in T, which should be considered when managing grazing and fodder production in these grasslands.Peer reviewe
A time resolved study of injection backgrounds during the first commissioning phase of SuperKEKB
We report on measurements of beam backgrounds during the first commissioning
phase of the SuperKEKB collider in 2016, performed with the plastic
scintillator and silicon photomultiplier-based CLAWS detector system. The
sub-nanosecond time resolution and single particle detection capability of the
sensors allow bunch-by-bunch measurements, enable CLAWS to perform a novel time
resolved analysis of beam backgrounds, and make the system uniquely suited for
the study of injection backgrounds. We present measurements of various aspects
of regular beam background and injection backgrounds which include time
structure and decay behavior of injection backgrounds, hit-energy spectra and
overall background rates. These measurements show that the elevated background
rates following an injection generally last for several milliseconds, with the
majority of the background particles typically observed within the first 500
us. The injection backgrounds exhibit pronounced patterns in time, connected to
betatron and synchrotron oscillations in the accelerator rings. The frequencies
of these patterns are determined from detector data.Comment: 19 pages, 12 figures, published in EPJ
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