Miracle-dz/UniFAR-FTUs huggingface dataset:
East Asian dust storm and weather disturbance: possible links to the Arctic Oscillation

In this work, the authors investigated the spring dust storm frequency variations in northern China and its relationship with weather disturbances, cold high, eddy kinetic energy (EKE), as well as the impact of the Arctic Oscillation (AO) on the dust storm frequency variations. It is found that there is a significantly decreasing trend of −26%/10 years in the dust storm frequency variations. In addition, the year‐to‐year variations are also remarkable, which account for 58.3% of the total variance of the dust storm frequency variations. The synoptic variance of 850 hPa height, EKE, and near‐surface cold highs are highly correlated with the dust storm frequency variations. During the last 40 years or so, there have been significant trends in synoptic variance, cold‐high frequency, and kinetic energy over northern China and Mongolia, which are −3.2, −4.0, and −5.0%/10 years, respectively. The trends are fairly consistent with long‐term variations of dust storm frequency. The AO shows good correlation with the interannual variations of the dust storm frequency. This out‐of‐phase relation is supported by the significantly negative correlations between AO index and eddy growth rate between 850/700 hPa in midlatitude East Asia, implying that AO can modulate weather disturbances and dust storm activities through influencing the atmospheric instability. It is found, however, that the spring AO index shows no evident long‐term trend. Land cover changes, global warming, and other climate teleconnections may, at least partly, be responsible for the secular decreasing of dust storm frequency over northern China. Copyright © 2006 Royal Meteorological Society.
Stochastic Analysis of Transport and Decay of a Solute in Heterogeneous Aquifers

A stochastic analysis of transport and first-order decay for a solute plume in a three-dimensionally heterogenous aquifer shows that a spatially variable decay rate produces effects both in the transient and steady state characteristics of the effective decay rate, effective solute velocity, and longitudinal macrodispersivity. The effective decay rate is found to be less than the mean, which implies that decay predictions that employ spatial averages of observations will tend to overestimate the rates of mass transformation due to decay. The effective solute velocity is found to be the only field scale coefficient dependent on the correlation between decay and log hydraulic conductivity. The longitudinal macrodispersivity is found to be reduced relative to that of a conservative/nondecaying solute. The characteristic timescale of the transient development of all field-scale coefficients is reduced by the presence of a heterogeneous decay rate. All of these trends are accentuated with increasing decay rate variability. Increased peak concentrations, earlier arrival times, and decreased plume spreading are practical consequences of the derived results. The stochastic analysis presented here provides a vehicle to link laboratory-scale measurements with these field-scale predictions.
Export of NOy from the North American boundary layer during 1996 and 1997 North Atlantic Regional Experiments

[1] This paper studies the removal timescales of the NOy originating from surface emissions of nitrogen oxides (NOx) and studies what fraction of the emissions reaches the free troposphere. These are important questions because NOx, which limits ozone production in the free troposphere, can be recycled from NOy after the primary NOx has been exhausted. We present an analysis of aircraft measurement data of odd nitrogen (NOy) and carbon monoxide (CO) taken during the North Atlantic Regional Experiment (NARE) in spring 1996 and fall 1997. Because CO has a relatively long chemical lifetime in the atmosphere and because it has similar emission patterns to NOx, CO concentrations can serve as a reference against which NOy removal can be studied. Correlating NOy and CO for different heights, we show that for the NARE 1997 (and NARE 1996) measurement campaigns, 78–91% (33–76%) of the surface NOy emissions were lost within the boundary layer or during transport from it, and only 3% (5%) of the emissions reached altitudes above 3 km. This accounted for ∼35% (∼41%) of the total NOy present above 3 km, the remainder coming from in situ emissions. In order to establish the timescales over which NOy is removed from the atmosphere, we determine the time elapsed between emission and measurement using a Lagrangian tracer transport model. We obtain approximate, effective mean e-folding lifetimes of NOy of 1.7 (1.8) days for the two intensives. On average, only 4% (9%) of the NOy remains in the atmosphere after 4–5 days. After 5–6 days, NOy from anthropogenic surface sources has been further depleted and accounts for <50% of the observed NOy. The rest of the observed NOy must come from in situ emissions, not from anthropogenic surface emissions.
A flume experiment on the formation of wood jams in rivers

A flume experiment is carried out to explore jamming of Large Woody Debris (LWD) in streams with complex morphology, occurring in mountain streams with in channel boulders or vegetation, in braided rivers or in floodplains during flood events. Non rooted, defoliated LWD is modeled using wood dowels and obstacles to motion are represented by vertical wood rods. Congested transport of LWD is simulated by insertion of a number (100) of dowels. The final position of the dowels is mapped and the observed jams are classified according to their size and position. The key member of each jam is identified and its trapping mechanism evaluated, either by leaning against a single obstacle or by bridging two obstacles. To mimic uncongested transport, the experiment is repeated for single pieces of wood, with subsequent removal. Longer dowels and shallower water result in shorter traveled distance. Wood pieces travel farther when congested transport is observed. The traveled distance of the wood pieces can be modeled using a Gamma distribution, for both congested and uncongested transport. Jams instead display Uniform traveled distance. The number of pieces displays an Exponential distribution. The degree of uniformity in space of jams and wood pieces is evaluated using a neighbor K statistic. Wood pieces show considerable clustering, while jams show sparse distribution. Eventually, the relationship between jams magnitude and position is explored, showing negative correlation. Model application is then discussed and some conclusions and future developments are outlined.
An invitation tu quasihomogeneous rigid geometric structures

A BSTRACT . This is a survey article dealing with quasihomogeneous geometric structures, in the sense that they are locally homogeneous on a nontrivial open set, but not on all of the manifold. Our motivation comes from Gromov’s open-dense orbit theorem which asserts that, if the pseudogroup of local automorphisms of a rigid geometric structure acts with a dense orbit, then this orbit is open. Fisher conjectured that the maximal open set of local homogeneity is all of the manifold as soon as the following three conditions are fulﬁlled: the automorphism group of the manifold acts with a dense orbit, the geometric structure is a G -structure (meaning that it is locally homogeneous at the ﬁrst order) and the manifold is compact. In a recent joint work, with Adolfo Guillot, we succeeded to prove Fisher’s conjecture for real analytic torsion free afﬁne connections on surfaces: we construct and classify those connections which are quasihomogenous; their automorphism group never acts with a dense orbit.
SMALL MORAINES IN SOUTHEASTERN ONTARIO

REESUME L'article decrit une serie de petits monticules oblongs, qu'il appelle petites moraines et qu'il a observes dans le voisinage de Kingston, Ont. Ces moraines sont reparties en petits groupes formant laches sur les terres basses, mais elles sont absentes des terrains sis a plus de 130 m. (425 pi.) au-dessus du niveau de la mer. Les materiaux dont sont constituees ces moraines se rangent principalement dans la gamme limon-sable et sont done plus fins que les depots glaciaires disparates qui recouvrent la region. On a observe des coquillages fossiles encastres dans l'une de ces moraines et on y voit l'evidence d'un retour de la masse de glace dans ce territoire apres qu'il en eut ete liberea la fin de la periode du Wisconsin. Ce phenomene n'avait pas encore ete decrit. On trouve d'autres petites moraines semblables a celles de Kingston sur une partie considerable de la peninsule de Niagara et on en a observe et decrit d'autres encore dans le voisinage de Goderich et dans la region du Lac Simcoe. Les auteurs sont d'avis que ces moraines constituent un element assez commun des paysages du sud de l'Ontario. On croit qu'elles existent egalement dans la partie nord de la province en bordure de la baie d'Hudson. Partout ces moraines sont etroitement liees a l'existence d'anciennes masses d'eau maintenant disparues. L'article traite de la genese de ces moraines. Les auteurs pensent qu'elles furent peut-etre formees par la compression de materiaux detrempes dans les crevasses de la surface inferieure de la masse de glace, mais ils soulignent le besoin d'etudes plus elaborees avant qu'il soil possible de presenter des conclusions definitives.
Transition of Experienced and New Graduate Nurses to a Pediatric Transition of Experienced and New Graduate Nurses to a Pediatric Hospital Hospital

This study reports on the 3-, 6, 12-, and 18-month outcomes of 118 newly hired registered nurses (RNs) who completed a 12-month transition-to-practice program at a pediatric hospital. Experienced RNs (n = 42) and new graduate RNs (n = 76) showed improved organization, prioritization, communication, and leadership skills over time. The experienced RNs reported better communication and leadership skills than the new graduate nurses. Results inform transition program development for both new and experienced nurses. The American Association of Colleges of Nursing (2012) predicts that, without a multifaceted approach, a national nursing shortage will occur by 2020. Many nurses leave their first position and sometimes the profession within the first year of employment (Baxter, 2010; Welding, 2011). Retaining nurses is a vital component of any approach to averting a nursing shortage. In an attempt to retain nurses, healthcare institutions often provide a transition-to-practice (TTP) or nurse residency program for new graduate nurses (NGN) entering the profession. The Institute of Medicine (2011) in its Future of Nursing report also recommends a transition program for nurses moving to a new specialty or to advanced practice roles. Completing a NGN transition program is associated with a decrease in nurse
Constitutive mechanical relations of solid-liquid composites in terms of grain-boundary contiguity

Macroscopic constitutive relations of solid-liquid composites are derived as functions of microscopic geometry described by grain-boundary contiguity. The model consists of solid grains, which make a framework through grain-to-grain contact, and an interstitial liquid phase. Contiguity is the essential geometric factor that determines the macroscopic mechanical properties of the granular composites, while the other factors such as liquid volume fraction affect the properties only indirectly through the contiguity. Contiguity is defined by the portion of the grain surface being in contact with the neighboring grains, and takes a value between 0 and 1. Total length of the solid-solid and solid-liquid phase boundaries observed in cross section can be quantitatively related to the contiguity. Contiguity φ can be extended to a tensor φij to cover anisotropic grain contact. The full anisotropic macroscopic elasticities are quantitatively derived as functions of contiguity. Also, as an attempt to apply the present formulation to viscous behaviors of solid-liquid composites, bulk and shear viscosities are derived as functions of contiguity. The results successfully predict the large structural sensitivities of these properties; the bulk and shear moduli (or viscosities) of the skeleton are drastically reduced by decreased contiguity and vanish when contiguity vanishes. For partially molten media under thermodynamic equilibrium, geometrical variation according to melt fraction and dihedral angle is quantitatively related to the variation of contiguity, and the acoustic properties are derived as functions of melt fraction and dihedral angle.
Measurements of landscape-scale fluxes of carbon dioxide in the Peruvian Amazon by vertical profiling through the atmospheric boundary layer

Vertical profiles of carbon dioxide were measured within and above the atmospheric boundary layer at a tropical forest site in the Peruvian Amazon during July 1996 using a tethered balloon sampling platform. Flask samples were collected within and above the mixed layer and analyzed off-site for carbon dioxide by nondispersive infrared spectrophotometry. Ozone and temperature vertical profiles were used to determine the boundary layer heights and growth rates. The mean values for methane, carbon monoxide, hydrogen, carbon-13, and oxygen-18 ratios were determined within and above the mixed layer. Daytime carbon dioxide flux values were calculated using the budget method. Nocturnal fluxes were estimated by integrating the carbon dioxide mixing ratios as a function of height from the ground to the inversion layer and dividing the total accumulated carbon dioxide by the time since sunset. The daytime carbon dioxide flux of −13 ± 2 μmol C m−2 s−1 and the nocturnal flux of +5.0 ± 1.0 μmol C m−2 s−1 are in good agreement with previous studies in the Brazilian Amazon.
Paleobotanical evidence for cool north polar climates in middle Cretaceous (Albian-Cenomanian) time

Mid-Cretaceous (Albian-Cenomanian) floras are abundant and diverse on the North Slope of Alaska. The older floras consist of conifers, cycadophytes, ferns, ginkgophytes, and sphenophytes (horsetails). Angiosperms appeared in latest Albian time and rapidly diversified. The preserved floras consist entirely of deciduous plants, with the exception of a microphyllous conifer, ferns, and sphenophytes. Deciduousness is evidence for strong seasonality, which for these floras might be variations in either light or temperature or both. Cool temperatures are suggested by the prevalence of toothed leaves among the angiosperms and the presence of large-leaved conifers. The paleobotanical evidence points to a mid-Cretaceous climate that was no warmer than cool temperate on the North Slope of Alaska.
Sensitivity of a GCM to changes in the droplet effective radius parameterization

The French Community Climate model (ARPEGE‐climat) has been used in relation to four different warm cloud droplet effective radius parameterizations in order to simulate the January and July climatologies. Two of these parameterizations depend upon the cloud character (maritime or continental). The comparison between the results of the different simulations reveals that the model is very sensitive to the effective radius parameterization change. This change induces differences up to 30Wm−2 in the global values of the radiative fluxes at the top of the atmosphere and at the surface level. Important differences are also induced in the zonally averaged short‐wave cloud radiative forcing, cloudiness and precipitation. At smaller scales, non negligible precipitation and surface temperature changes are also observed. The comparison between the simulation results obtained by using model versions containing the above parameterizations reveals that two of them considerably improve the agreement between model and climatological cloudiness, thus allowing a pertinent choice of the most appropriate cloud droplet effective radius parameterization.
Do global warming targets limit heatwave risk?

Climate change mitigation targets are often described in terms of annually averaged global mean temperature increases. However local interpretation of impacts resulting from these targets are required if the public is to have a sound appreciation of their consequences. Some of the largest impacts are likely to arise from changes in extreme events, for example heatwaves and floods. This article estimates future regional heat extreme changes consistent with specific global warming targets, using a new and presently unique ensemble of physically plausible climate simulations. We find that a subset of ensemble members giving globally averaged temperature increases of 2.0 ± 0.5°C shows a wide range of changes in regional temperature extremes. For example, changes in extreme single‐day hot events range between 2 and 6 °C for large parts of Europe, North America and Asia for this target. Plausible variations in the model representation of forest roughness length, vegetation root depth and boundary layer cloud make the largest individual contributions to the spread of changes found in different parts of the world. However, a wide range of processes contribute to the uncertainties in the regional changes, particularly through their direct or indirect influences on the simulation of soil moisture.
Observed low frequency variability of the Brazil Current front

[1] The Brazil Current is a weak western boundary current, the southwest component of the South Atlantic subtropical gyre, which is the main conduit of upper ocean waters in the region. The objective of this work is to report on observed low frequency variability of the Brazil Current front using satellite-derived sea height anomaly and sea surface temperature observations during the 1993–2008 period. The variability of the front is studied in terms of the separation of the Brazil Current front from the continental shelf break. During the study period, estimates of this parameter vary 6 degrees in latitude, and the mean monthly estimates exhibit a shift to the south of approximately 1.5 degrees. Statistically significant changes are not observed in the geostrophic transport of the Brazil and Malvinas currents, suggesting that the low-frequency changes of the Brazil Current front are governed by different mechanisms than the seasonal variability of these surface currents. Surface drifter trajectories and simulations using synthetic drifters are consistent with the observed shift to the south of the Brazil Current front. Trends of eddy kinetic energy, sea height anomaly, sea surface temperature and wind stress curl are also in agreement with the variability reported here. Wavelet transform analysis revealed interesting changes in the periodicity of the latitude of separation of the Brazil Current front from the continental shelf break, with periods ranging from semiannual to biannual. Longer records, together with comprehensive numerical experiments, will ultimately be needed to determine the origin of these changes.
The Influence of Wildfire on Aqueous-Extractable Soil Solutes in Forested and Wet Meadow Ecosystems Along the Eastern Front of the Sierra-Nevada Range, California

Information is lacking regarding the influence of pre-fire microsite conditions on post-wildfire soil chemical properties. Following a 1994 wildfire along the eastern front of the Sierra Nevada range, California, high performance ion exchange chromatography was used to quantify anions and cations in aqueous soil extracts by plant microsite (Pinus jeffreyi subcanopy, Calocedrus decurrens subcanopy, Carer microptera meadow, Salix scouleriana subcanopy), by depth (ash or litter, mineral soil horizon 0-5 cm), and by treatment (unburned, burned). As compared to the unburned treatment, post-wildfire ash and surface mineral horizons had significantly (P less than or equal to 0.05) higher concentrations of sodium, magnesium, formate, and chloride. Plant microsite interacted significantly with treatment for ammonium; all plant microsites had significantly higher ammonium in burned treatments and burned S. scouleriana and C. microptera microsites had significantly more ammonium than the C. decurrens or P. jeffreyi microsites. For pH and acetate there was a significant treatment × depth interaction in which concentrations were highest in burned ash layers. For sulfate, ortho-phosphate, and calcium, there was a significant plant microsite × treatment × depth interaction. In general, post-wildfire ash and soil mineral layers had significantly more sulfate and calcium than the unburned controls; ash layers contained significantly less ortho-phosphate than unburned litter layers. There was a significant treatment × depth interaction for magnesium, chloride, formate, acetate, potassium, and nitrate. Initial post-wildfire levels of short-chained aliphatic carboxylic acids were very high, especially in ash layers, and did not decline to preburn values by the following summer.
Hydrolytic Degradation of Estane 5703

Relative to the unaged Estane{reg_sign} 5703, heating decreases the modulus and ultimate stress for both the dry and humid samples. The sample aged in dry air, quickly recovered to its original mechanical properties. The reversibility of the mechanical properties is a result of the reorganization of the hard segments into domains. For the Estane 5703 samples aged in humid air, the mechanical properties only partially recovered with time. Molecular weight data confirm that differences in the extent of the recovery for the samples aged under humid environments are likely due to the hydrolytic scission of the polyester soft segments. Since the tensile moduli are similar for the samples aged in both the dry and humid environments, it is believed that the phase behavior of the hard domains dictate the mechanical properties at low extensions. However, at higher elongations, the mechanical properties are dominated by the soft segments. Both the influences of morphological changes and chemical changes induced by heating must be considered in multiphase polymers when accelerated aging is utilized to predict long term polymer properties. After accelerated aging experiments, the morphology must be allowed to recover to equilibrium conditions in order to assess the extent of degradation and aging. Also, the effect of different humidities on the rate of hydrolytic degradation are presented.
Probability in the Engineering and Informational Sciences

Motivated by non-Poisson stochastic variability found in service system arrival data, we extend established service system staffing algorithms using the square-root staffing formula to allow for non-Poisson arrival processes. We develop a general model of the non-Poisson non-stationary arrival process that includes as a special case the non-stationary Cox process (a modification of a Poisson process in which the rate itself is a non-stationary stochastic process), which has been advocated in the literature. We characterize the impact of the non-Poisson stochastic variability upon the staffing through the heavy-traffic limit of the peakedness (ratio of the variance to the mean in an associated stationary infinite-server queueing model), which depends on the arrival process through its central limit theorem behavior. We provide simple formulas to quantify the performance impact of the non-Poisson arrivals upon the staffing decisions, in order to achieve the desired service level. We conduct simulation experiments with non-stationary Markov-modulated Pois-son arrival processes with sinusoidal arrival rate functions to demonstrate that the staffing algorithm is effective in stabilizing the time-varying probability of delay at designated targets.