704 research outputs found
Herijking EHS Noord-Holland : een toets vanuit het perspectief van ruimtelijke samenhang
De realisatie van de Ecologische Hoofdstructuur in de Provincie Noord-Holland ligt achter op schema. Hierom hebben Gedeputeerde Staten van Noord-Holland besloten te onderzoeken of via een herbegrenzing een groter deel van de EHS nog is te realiseren. De gebieden die in aanmerking komen voor herbegrenzing zijn beoordeeld op de ruimtelijke samenhang van het gebied zelf én de mate waarin het gebied bijdraagt aan de omgeving. Op basis van de analyses mag geconcludeerd worden dat de beoogde herbegrenzing in Noord-Holland goed is voor de ruimtelijke samenhang van de provinciale EHS. Tevens zijn er twee quick-scan analyses uitgevoerd die een positief beeld laten zien van de herbegrenzingen op het niveau van Natuurdoelen en in relatie tot Natura2000-gebieden
Acute and chronic respiratory effects of sodium borate particulate exposures.
This study examined work-related chronic abnormality in pulmonary function and work-related acute irritant symptoms associated with exposure to borate dust in mining and processing operations. Chronic effects were examined by pulmonary function at the beginning and end of a 7-year interval. Time-specific estimates of sodium borate particulate exposures were used to estimate cumulative exposure during the study interval. Change in pulmonary function over the 7 years was found unrelated to the estimate of cumulative exposure during that interval. Exposure-response associations also were examined with respect to short-term peak exposures and incidence of five symptoms of acute respiratory irritation. Hourly measures of health outcome and continuous measures of particulate exposure were made on each subject throughout the day. Whenever a subject reported one of the irritant symptoms, a symptom intensity score was also recorded along with the approximate time of onset. The findings indicated that exposure-response relationships were present for each of the specific symptoms at several symptom intensity levels. The associations were present when exposure was estimated by both day-long and short-term (15-min) time-weighted average exposures. Associations persisted after taking account of smoking, age, and the presence of a common cold. No significant difference in response rate was found between workers exposed to different types of sodium borate dusts
Association Between Acute Kidney Injury Hospital Visits and Environmental Heat Stress at a Nicaraguan Sugarcane Plantation
Background: Mesoamerican sugarcane cutters are at a high risk of chronic kidney disease of non-traditional origin, a disease likely linked to heat-related acute kidney injury (AKI). Studies in general populations have described a positive association between high environmental temperatures and clinically assessed kidney outcomes, but there are no studies in occupational settings. Method: We accessed routine records of clinically diagnosed AKI (AKI-CD) and wet bulb globe temperatures (WBGT) at a large Nicaraguan sugarcane plantation and modeled the relationship between these using negative binomial regression. A rest-shade-hydration intervention was gradually enhanced during the study period, and efforts were made to increase the referral of workers with suspected AKI to healthcare. Results: Each 1°C WBGT was associated with an 18% (95% confidence interval [CI]: [4, 33%]) higher AKI-CD rate on the same day and a 14% (95% CI [−5, 37%]) higher rate over a week. AKI-CD rates and severity, and time between symptoms onset and diagnosis decreased during the study period, that is, with increasing rest-shade-hydration intervention. Symptoms and biochemical signs of systemic inflammation were common among AKI-CD cases. Discussion: Occupational heat stress, resulting from heavy work in environmental heat, was associated with a higher rate of clinically diagnosed AKI in a population at risk of CKDnt. Promoting rest-shade-hydration may have contributed to reducing AKI rates during the study period. Occupational health and safety personnel have key roles to play in enforcing rest, shade, and hydration practices, referring workers with suspected AKI to healthcare as well as collecting and analyzing the data needed to support workplace heat stress interventions
X-ray modelling of galaxy cluster gas and mass profiles
We present a parametric analysis of the intracluster medium and gravitating
mass distribution of a statistical sample of 20 galaxy clusters using the
phenomenological cluster model of Ascasibar and Diego. We describe an effective
scheme for the estimation of errors on model parameters and derived quantities
using bootstrap resampling. We find that the model provides a good description
of the data in all cases and we quantify the mean fractional intrinsic scatter
about the best-fit density and temperature profiles, finding this to have
median values across the sample of 2 and 5 per cent, respectively. In addition,
we demonstrate good agreement between r500 determined directly from the model
and that estimated from a core-excluded global spectrum. We compare cool core
and non-cool core clusters in terms of the logarithmic slopes of their gas
density and temperature profiles and the distribution of model parameters and
conclude that the two categories are clearly separable. In particular, we
confirm the effectiveness of the logarithmic gradient of the gas density
profile measured at 0.04 r500 in differentiating between the two types of
cluster.Comment: 8 pages, 7 figures, accepted for publication in MNRA
Quantum authentication with key recycling
We show that a family of quantum authentication protocols introduced in
[Barnum et al., FOCS 2002] can be used to construct a secure quantum channel
and additionally recycle all of the secret key if the message is successfully
authenticated, and recycle part of the key if tampering is detected. We give a
full security proof that constructs the secure channel given only insecure
noisy channels and a shared secret key. We also prove that the number of
recycled key bits is optimal for this family of protocols, i.e., there exists
an adversarial strategy to obtain all non-recycled bits. Previous works
recycled less key and only gave partial security proofs, since they did not
consider all possible distinguishers (environments) that may be used to
distinguish the real setting from the ideal secure quantum channel and secret
key resource.Comment: 38+17 pages, 13 figures. v2: constructed ideal secure channel and
secret key resource have been slightly redefined; also added a proof in the
appendix for quantum authentication without key recycling that has better
parameters and only requires weak purity testing code
Aanpassing Model for Nature Policy aan typologie Subsidiestelsel Natuur en Landschap : fase 1
Het Model for Nature Policy (MNP) wordt voor het Planbureau voor de Leefomgeving ontwikkeld om het natuurbeleid van regionaal tot landelijk niveau te evalueren. Het model gebruikt de vegetatie als basis voor de voorspellingen: de natuurdoeltypenkaart. Beheerders en overheid zijn echter over-gegaan naar het Subsidiestelsel Natuur en Landschap (SNL) met als vegetatietypen de beheertypen en bijbehorende vegetatiekaart. Om MNP te laten aansluiten bij SNL is in dit onderzoek de eerste stap gezet om het model geschikt te maken voor doorrekeningen op basis van de SNL-vegetatiekaart. De soorten in het model zijn gekoppeld aan de beheertypen en er zijn nieuwe draagkrachten gekoppeld aan een soort-beheertypecombinatie. Alle soorten in het MNP zijn vervolgens getest door de voorspelde verspreiding te vergelijken met de verspreidingswaarnemingen van de particuliere gegevensbeherende organisaties (PGO’s). Elke soort is beoordeeld als goed, matig of slecht. Van de 256 soorten werden er 24 als slecht beoordeeld en deze dienen nader onderzocht te worden. De vergelijking heeft alleen plaatsgevonden op basis van draagkracht. Grondwaterstand en kritische depositiewaarden zijn nog niet meegenomen in de test. Toch gaven de eerste resultaten een redelijk goed beeld. Het detailniveau van de beheertypenkaart dient verbeterd te worden om goede voorspellingen te kunnen doe
Modellering van bosbeheer in SUMO
In het vegetatievoorspellingsmodel SUMO is de beheermodule uitgebreid met twee vormen van bosbeheer: regulier bosbeheer en hakhoutbeheer. Het regulier bosbeheer bestaat uit elke vijf jaar dunnen en kaalkap aan het eind van de omloopperiode. De omloopperiode en het dunningspercentage zijn per boomsoort verschillend. De effecten van het beheer zijn een variërende stikstofbeschikbaarheid (gering na dunnen en groot na kappen) en een betere simulatie van de biomassa: teruggang in biomassa van de bomen na dunnen, en na kappen een enorme toename van de biomassa van de kruiden. Ook het hakhoutbeheer (voor eiken-, wilgen- en elzenhakhout) heeft veel invloed op de biomassa, al is verder onderzoek naar de biomassaverdeling over de functionele typen noodzakelijk. Toevoeging van beide beheersvormen geeft een duidelijke verbetering te zien van de simulatie van de bosontwikkeling
Attacks on quantum key distribution protocols that employ non-ITS authentication
We demonstrate how adversaries with unbounded computing resources can break
Quantum Key Distribution (QKD) protocols which employ a particular message
authentication code suggested previously. This authentication code, featuring
low key consumption, is not Information-Theoretically Secure (ITS) since for
each message the eavesdropper has intercepted she is able to send a different
message from a set of messages that she can calculate by finding collisions of
a cryptographic hash function. However, when this authentication code was
introduced it was shown to prevent straightforward Man-In-The-Middle (MITM)
attacks against QKD protocols.
In this paper, we prove that the set of messages that collide with any given
message under this authentication code contains with high probability a message
that has small Hamming distance to any other given message. Based on this fact
we present extended MITM attacks against different versions of BB84 QKD
protocols using the addressed authentication code; for three protocols we
describe every single action taken by the adversary. For all protocols the
adversary can obtain complete knowledge of the key, and for most protocols her
success probability in doing so approaches unity.
Since the attacks work against all authentication methods which allow to
calculate colliding messages, the underlying building blocks of the presented
attacks expose the potential pitfalls arising as a consequence of non-ITS
authentication in QKD-postprocessing. We propose countermeasures, increasing
the eavesdroppers demand for computational power, and also prove necessary and
sufficient conditions for upgrading the discussed authentication code to the
ITS level.Comment: 34 page
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