1,809 research outputs found
Inorganic Chemistry in the Mountain Critical Zone : Are the mountain water towers of contemporary society under threat by trace contaminants ?
Potentially harmful trace elements (PHTEs) do not accumulate homogeneously over mountainous area. Generally, highland areas receive more wet deposition, aerosols, and ions than surrounding lowlands ones, mainly due to orographic enhancement. Within mountainous areas, however, the accumulation of PHTEs is much more complex. Direct cloud deposition of contaminants could act as an important pathway of deposition either from a regional low-altitude, cloud level, orographic clouds, or haze whose frequency of occurrence is much higher than surrounding lowlands areas. The accumulation legacy of PHTEs from local human activities should also be considered when investigating PHTE distribution in mountainous areas. Combined with other phenomena, the PHTE accumulation patterns could be highly variable depending on local topography, dominant winds, and vegetation cover, as well as present and past local practices. Despite their remoteness, mountain ecosystems are highly sensitive to PHTEs loadings
Digital twins : a critical discussion on their potential for supporting policyâmaking and planning in urban logistics
Poor logistics efficiency, due to low load factors caused by high demand fragmentation, will have relevant negative consequences for cities in terms of pollution, congestion and overall city liveability. Policy-makers should equip themselves with appropriate tools to perform reliable, comprehensive and timely analyses of urban logistics scenarios, also considering upcoming (i) technological changes, (ii) business model evolutions and (iii) spatial-temporal changes these innovations will produce. This paper discusses the Digital Twin (DT) concept, illustrating the role it might play and clarifying how to properly conceive it with respect to urban freight transport policy-making and planning. The main message is that without a sound theory and knowledge with respect to the relationships linking contextual reality and choice/behaviour, it is not possible to make sense of what happens in the real world. Therefore, the joint use of behavioural and simulation models should characterise a DT within a Living Lab approach so to stimulate effective, well-informed and participated planning processes, but also to forecast both behaviour and reactions to structural changes and policy measures implementations. Keywords: digital twins, urban freight, living lab, behavioural models, policy, planningpublishedVersio
Gauge Dependence of the Resummed Thermal Gluon Self Energy
The gauge dependence of the hot gluon self energy is examined in the context
of Pisarski's method for resumming hard thermal loops. Braaten and Pisarski
have used the Ward identities satisfied by the hard corrections to the n-point
functions to argue the gauge fixing independence of the leading order resummed
QCD plasma damping rate in covariant and strict Coulomb gauges. We extend their
analysis to include all linear gauges that preserve rotational invariance and
display explicitly the conditions required for gauge fixing independence. It is
shown that in covariant gauges the resummed damping constant is gauge fixing
independent only if an infrared regulator is explicitly maintained throughout
the calculation.Comment: 29 pages, report BI-TP 92/19, LPTHE-Orsay 92/32, WIN-TH-92/02 (June
1992
Finite momentum meson correlation functions in a QCD plasma
The finite momentum meson spectral function (MSF) in the pseudoscalar channel
is evaluated, adopting for the fermionic propagators HTL expressions. The
different contributions to the meson spectral functions are clearly displayed.
Our analysis may be of relevance for lattice studies of MSF based so far on the
Maximum Entropy Method. As a further step the correlation function along the
(imaginary-) temporal direction is evaluated.Comment: 29 pages, 25 figures, submitted to Nucl.Phys.
75%-efficiency blue generation from an intracavity PPKTP frequency doubler
We report on a high-efficiency 461 nm blue light conversion from an external
cavity-enhanced second-harmonic generation of a 922 nm diode laser with a
quasi-phase-matched KTP crystal (PPKTP). By choosing a long crystal (LC=20 mm)
and twice looser focusing (w0=43 m) than the "optimal" one, thermal
lensing effects due to the blue power absorption are minimized while still
maintaining near-optimal conversion efficiency. A stable blue power of 234 mW
with a net conversion efficiency of eta=75% at an input mode-matched power of
310 mW is obtained. The intra-cavity measurements of the conversion efficiency
and temperature tuning bandwidth yield an accurate value d33(461 nm)=15 pm/V
for KTP and provide a stringent validation of some recently published linear
and thermo-optic dispersion data of KTP
MT-7716, a potent NOP receptor agonist, preferentially reduces ethanol seeking and reinforcement in post-dependent rats
Dysregulation of the nociceptin (N/OFQ) system has been implicated in alcohol abuse and alcoholism, and growing evidence suggests that targeting this system may be beneficial for treating alcoholism. To further explore the treatment target potential of the N/OFQ system, the novel non-peptide, small-molecule N/OFQ (NOP) agonist MT-7716, (R)-2-3-[1-(Acenaphthen-1-yl)piperidin-4-yl]-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl-N-methylacetamide hydrochloride hydrate, was examined for its effects on ethanol self-administration and stress-induced reinstatement of alcohol seeking in non-dependent and post-dependent rats. Male Wistar rats were trained to self-administer ethanol and then made ethanol dependent via repeated intragastric ethanol intubation. The effects of MT-7716 (0.3 and 1 mg/kg; PO) on alcohol self-administration were determined 2 weeks following dependence induction, when baseline self-administration was restored. Effects of MT-7716 on stress-induced reinstatement were tested in separate cohorts of rats, 1 and 3 weeks post-withdrawal. MT-7716 reduced alcohol self-administration and stress-induced reinstatement of alcohol seeking in post-dependent rats, but was ineffective in non-dependent animals. Moreover, the prevention of stress-induced reinstatement by MT-7716 was more pronounced at 3 weeks post-dependence. The results further confirm treatment target potential for the NOP receptor and identify non-peptide NOP agonists as promising potential treatment drugs for alcohol abuse and relapse prevention. The findings also support dysregulation of the N/OFQ system as a factor in alcohol seeking and reinforcement
Ethics and biobanks
Biobank research has been the focus of great interest of scholars and regulatory bodies who have addressed different ethical issues. On the basis of a review of the literature it may be concluded that, regarding some major themes in this discussion, a consensus seems to emerge on the international scene after the regular exchange of arguments in scientific journals. Broad or general consent is emerging as the generally preferred solution for biobank studies and straightforward instructions for coding will optimise privacy while facilitating research that may result in new methods for the prevention of disease and for medical treatment. The difficult question regarding the return of information to research subjects is the focus of the current research, but a helpful analysis of some of the issues at stake and concrete recommendations have recently been suggested
Effective action for the order parameter of the deconfinement transition of Yang-Mills theories
The effective action for the Polyakov loop serving as an order parameter for
deconfinement is obtained in one-loop approximation to second order in a
derivative expansion. The calculation is performed in dimensions,
mostly referring to the gauge group SU(2). The resulting effective action is
only capable of describing a deconfinement phase transition for
. Since, particularly in , the system is
strongly governed by infrared effects, it is demonstrated that an additional
infrared scale such as an effective gluon mass can change the physical
properties of the system drastically, leading to a model with a deconfinement
phase transition.Comment: 23 pages, 4 figures, minor improvements, version to appear in PR
Seasonal change in the daily timing of behaviour of the common vole, Microtus arvalis
1. Seasonal effects on daily activity patterns in the common vole were established by periodic trapping in the field and continuous year round recording of running wheel and freeding activity in cages exposed to natural meteorological conditions.
2. Trapping revealed decreased nocturnality in winter as compared to summer. This was paralelled by a winter reduction in both nocturnal wheel running and feeding time in cages.
3. Frequent trap checks revealed a 2 h rhythm in daytime catches in winter, not in summer. Cage feeding activity in daytime was always organized in c. 2 h intervals, but day-to-day variations in phase blurred the rhythm in summer in a summation of individual daily records. Thus both seasonal and short-term temporal patterns are consistent between field trappings and cage feeding records.
4. Variables associated with the seasonal change in daily pattern were: reproductive state (sexually active voles more nocturnal), age (juveniles more nocturnal), temperature (cold days: less nocturnal), food (indicated by feeding experiments), habitat structure (more nocturnal in habitat with underground tunnels).
5. Minor discrepancies between field trappings and cage feeding activity can be explained by assuming increased trappability of voles in winter. Cage wheel running is not predictive of field trapping patterns and is thought to reflect behavioral motivations not associated with feeding but with other activities (e.g., exploratory, escape, interactive behaviour) undetected by current methods, including radiotelemetry and passage-counting.
6. Winter decrease in nocturnality appears to involve a reduction in nocturnal non-feeding and feeding behaviour and is interpreted primarily as an adaptation to reduce energy expenditure in adverse but socially stable winter conditions.
Categorization of compensatory motions in transradial myoelectric prosthesis users
Background: Prosthesis users perform various compensatory motions to accommodate for the loss of the hand and wrist as well as the reduced functionality of a prosthetic hand.
Objectives: Investigate different compensation strategies that are performed by prosthesis users.
Study Design: Comparative analysis
Methods: 20 able-bodied subjects and 4 prosthesis users performed a set of bimanual activities. Movements of the trunk and head were recorded using a motion capture system, and a digital video recorder. Clinical motion angles were calculated to assess the compensatory motions made by the prosthesis users. The video recording also assisted in visually identifying the compensations.
Results: Compensatory motions by the prosthesis users were evident in the tasks performed (slicing and stirring activities) as compared to the benchmark of able-bodied subjects. Compensations took the form of a measured increase in range of motion, an observed adoption of a new posture during task execution, and pre-positioning of items in the workspace prior to initiating a given task.
Conclusion: Compensatory motions were performed by prosthesis users during the selected tasks. These can be categorized into three different types of compensations
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