Miracle-dz/UniFAR-FTUs huggingface dataset:
Structured Compressive Sensing-Based Spatio-Temporal Joint Channel Estimation for FDD Massive MIMO

Massive MIMO is a promising technique for future 5G communications due to its high spectrum and energy efficiency. To realize its potential performance gain, accurate channel estimation is essential. However, due to massive number of antennas at the base station (BS), the pilot overhead required by conventional channel estimation schemes will be unaffordable, especially for frequency division duplex (FDD) massive MIMO. To overcome this problem, we propose a structured compressive sensing (SCS)-based spatio-temporal joint channel estimation scheme to reduce the required pilot overhead, whereby the spatio-temporal common sparsity of delay-domain MIMO channels is leveraged. Particularly, we first propose the nonorthogonal pilots at the BS under the framework of CS theory to reduce the required pilot overhead. Then, an adaptive structured subspace pursuit (ASSP) algorithm at the user is proposed to jointly estimate channels associated with multiple OFDM symbols from the limited number of pilots, whereby the spatio-temporal common sparsity of MIMO channels is exploited to improve the channel estimation accuracy. Moreover, by exploiting the temporal channel correlation, we propose a space-time adaptive pilot scheme to further reduce the pilot overhead. Additionally, we discuss the proposed channel estimation scheme in multicell scenario. Simulation results demonstrate that the proposed scheme can accurately estimate channels with the reduced pilot overhead, and it is capable of approaching the optimal oracle least squares estimator.
High-Latitude H I in NGC 2613: Buoyant Disk-Halo Outflow

We combine new VLA D configuration H I data of NGC 2613 with previous high-resolution data to show new disk-halo features in this galaxy. The global H I distribution is modeled in detail using a technique that can disentangle the effects of inclination from scale height and can also solve for the average volume density distribution in and perpendicular to the disk. The model shows that the galaxy's inclination is on the low end of the range given by Chaves & Irwin in a previous paper and that the H I disk is thin (ze = 188 pc), showing no evidence for halo. Numerous discrete disk-halo features are observed, however, achieving z heights up to 28 kpc from midplane. One prominent feature in particular, of mass 8 × 107 M☉ and height 22 kpc, is seen on the advancing side of the galaxy at a projected galactocentric radius of 15.5 kpc. If this feature achieves such high latitudes because of events in the disk alone, then input energies of order ~1056 ergs are required. We have instead investigated the feasibility of such a large feature being produced via buoyancy (with drag) within a hot, preexisting X-ray corona. Reasonable plume densities, temperatures, stall height (~11 kpc), outflow velocities, and ages can indeed be achieved in this way. The advantage of this scenario is that the input energy need only be sufficient to produce blowout, a condition that requires a reduction of 3 orders of magnitude in energy. If this is correct, there should be an observable X-ray halo around NGC 2613.
Implicit Learning and Acquisition of Music

Implicit learning is a core process for the acquisition of a complex, rule-based environment from mere interaction, such as motor action, skill acquisition, or language. A body of evidence suggests that implicit knowledge governs music acquisition and perception in nonmusicians and musicians, and that both expert and nonexpert participants acquire complex melodic, harmonic, and other features from mere exposure. While current findings and computational modeling largely support the learning of chunks, some results indicate learning of more complex structures. Despite the body of evidence, more research is required to support the cross-cultural validity of implicit learning and to show that core and more complex music theoretical features are acquired implicitly.
Including Individuals with Memory Impairment in the Research Process: The Importance of Scales and Response Categories Used in Surveys

Several ethical considerations emerge when conducting research with memory-impaired individuals, including the individuals' ability to comprehend and accurately respond to survey questions. However, little empirical research exists on how to format surveys to decrease cognitive demands, thereby allowing researchers to more accurately survey this population. The current study presents data from structured interviews with 125 community-residing, memory-impaired older adults about their illness experience. The interview contained 14 scales varying in subjectivity, directionality, and response choice content. While objectivity did not affect participants' ability to use the full range of responses, participants with greater cognitive impairment tended to use simpler, dichotomous response categories, especially when questions had bidirectional response choices. Results suggest that memory-impaired individuals can participate in survey research, that such surveys should contain unidirectional frequency/amount items when possible, and that not all memory-impaired individuals will have difficulty completing surveys.
The 'segment length curse' in long tree-ring chronology development for palaeoclimatic studies

The problem of constructing millennia-long tree-ring chronologies from overlapping segments of cross-dated ring-width series is reviewed, with an emphasis on preserving very low-frequency signals potentially due to climate. In so doing, a fundamental statistical problem coined the 'segment length curse' is introduced. This 'curse' is related to the fact that the maximum wavelength of recoverable climatic information is ordinarily related to the lengths of the individual tree-ring series used to construct the millennia-long chronology. Simple experiments with sine waves are used to illustrate this fact. This is followed by more realistic experiments using a long bristlecone pine series that is randomly cut into a number of 1000-, 500- and 200-year segments and standardized using three very conservative methods. When compared against the original, uncut series, the resulting 'chronologies' show the effects of segment length even when the most conservative and noncommittal method of tree-ring standardiza tion is applied (i.e., a horizontal line through the mean). Alternative schemes of chronology development are described that seek to exorcise the segment length curse. While they show some promise, none is universal in its applicability and this problem still remains largely unsolved.
Review of aerosol mass scattering efficiencies from ground-based measurements since 1990

[1] We performed a survey of ground-based estimates of aerosol mass scattering efficiencies (αsp, m2 g−1) for various aerosol species and size modes from peer-reviewed literature published since 1990. Accurate estimates of αsp are important in aerosol modules of global circulation and chemical transport models to compute radiative forcing effects of aerosols and in chemical extinction budgets used for visibility regulatory purposes. The variety of techniques used to compute αsp can be categorized into four basic methods. We separate reported αsp on the basis of the methods used to derive them and normalize estimates of αsp to a common dry relative humidity (RH, RH ≈ 0%) and mass composition basis, removing some of the variability inherent in αsp reported under different monitoring conditions. The values of αsp reviewed here represent common aerosol species and correspond to data from a variety of time periods and global locations. For the 60 studies reviewed, the average (and one standard deviation) αsp (at visible wavelengths) for fine mode dry ammonium sulfate and dry ammonium nitrate are 2.5 ± 0.6 m2 g−1 and 2.7 ± 0.5 m2 g−1, respectively. The fine mode particulate organic matter αsp is 3.9 ± 1.5 m2 g−1. The fine mode dust αsp is 3.3 ± 0.6 m2 g−1and the fine mode dry sea salt αsp is 4.5 ± 0.9 m2 g−1. Coarse mode αsp estimates are also reported. The range of αsp may reflect differences in aerosol morphology, age, physicochemical properties and mixing state; however, this survey suggests that the type of method used to derive αsp can contribute considerably to the variability observed.
A High-Resolution Map of the Cosmic Microwave Background around the North Celestial Pole

We present a Wiener-filtered map of the cosmic microwave background (CMB) fluctuations in a cap with 15° diameter, centered at the north celestial pole. The map is based on the 1993-1995 data from the Saskatoon (SK) experiment, with an angular resolution around 1° in the frequency range 27.6-44.1 GHz. The signal-to-noise ratio in the map is of order 2, and some individual hot and cold spots are significant at the 5 σ level. The spatial features are found to be consistent from year to year, which reinforces the conclusion that the SK results are not dominated by residual atmospheric contamination or other noncelestial signals.
Wintertime mixed layer measurements at Maud Rise, Weddell Sea

[1] Sea ice plays a crucial role in the exchange of heat between the ocean and the atmosphere, and areas of intense air-sea-ice interaction are important sites for water mass modification. The Weddell Sea is one of these sites where a relatively thin first-year ice cover is constantly being changed by mixing of heat from below and stress exerted from the rapidly changing and intense winds. This study presents mixed layer turbulence measurements obtained during two wintertime drift stations in August 2005 in the eastern Weddell Sea, close to the Maud Rise seamount. Turbulence in the boundary layer is found to be controlled by the drifting ice. Directly measured heat fluxes compare well with previous studies and are well estimated from the mixed layer temperatures and mixing. Heat fluxes are also found to roughly balance the conductive heat flux in the ice; hence, little freezing/melting was observed. The under-ice topography is estimated to be hydraulically very smooth; comparison with a steady 1-D model shows that these estimates are made too close to the ice-ocean interface to be representative for the entire ice floe. The main source and sink of turbulent kinetic energy are shear production and dissipation. Observations indicate that the dynamics of the under-ice boundary layer are influenced by a horizontal variability in mixed layer density and an increasing amount of open leads in the area.
Effects of Black Carbon on Climate: Advances in Measurement and Modeling

Black carbon (BC) particles are non-spherical agglomerates consisting of hundreds or thousands of graphitic carbon spherules the diameters of which are about 15–50 nm. The spherules are graphitic in their molecular states and are, thus, strongly light-absorbing. BC particles are emitted by the incomplete combustion of carbon-based fossil fuels and biomass. BC mass in the atmosphere resides in agglomerates typically between 100 and 600 nm in diameter. They influence the global radiation budget by strongly absorbing solar radiation in the visible wavelengths and by changing the albedo of snow through deposition. Radiative forcing (RF) of BC is defined as the change in net radiative flux at the top of the atmosphere in W m−2 due to a change of BC between the pre-industrial time and present-day periods. The instantaneous direct radiative forcing of airborne BC particles (BC DRF), which does not include climate feedbacks, is determined by their absorption cross sections and spatial distributions. The distributions of BC are, in turn, controlled by its emission, dynamical transport, and loss during transport. The absorption cross section of BC is controlled by its optical properties (i.e., refractive index) and microphysical properties (size distribution, morphology, and mixing state). Because it is crucial to characterize these parameters, we first developed techniques to measure them accurately. Newlydeveloped BC measurement technologies constitute the firm basis of our studies. The techniques were applied to laboratory experiments and field observations of BC particles in air and rainwater. We also developed regional scale three-dimensional (3D) models to quantitatively interpret the observational results. One of the models calculates BC aging and optical/radiative processes explicitly without parameterizations. The reliable field measurements and model calculations of BC has enabled an improved understanding of the physical and chemical processes that control the microphysical properties of BC. We also quantitatively analyzed the emission rate, transport, and wet removal processes of BC in Asia by comparing the observed, and model-calculated, BC distributions. Through aircraft measurements in the Arctic, we characterized emissions of BC from biomass burning and the strong seasonal variations of the efficiency of transport of BC from different regions in the northern hemisphere to the Arctic. A number of findings, brought about by the observational and modeling efforts, demonstrate the strength of our innovative methodologies for improving the estimate of BC DRF, which has been highly uncertain thus far.
Effectiveness of Multifaceted Hospitalwide Quality Improvement Programs Featuring an Intervention to Remove Unnecessary Urinary Catheters at a Tertiary Care Center in Thailand

Objective. To evaluate the efficacy of a multifaceted hospitalwide quality improvement program that featured an intervention to remind physicians to remove unnecessary urinary catheters. Methods. A hospitalwide preintervention-postintervention study was conducted over 2 years (July 1, 2004, through June 30, 2006). The intervention consisted of nurse-generated daily reminders that were used by an intervention team to remind physicians to remove unnecessary urinary catheters, beginning 3 days after insertion. Clinical, microbiological, pharmaceutical, and cost data were collected. Results. A total of 2,412 patients were enrolled in the study. No differences were found in the demographic and/or clinical characteristics of patients between the preintervention and postintervention periods. After the intervention, reductions were found in the rate of inappropriate urinary catheterization (mean rate, preintervention vs postintervention, 20.4% vs 11% [P = .04]), the rate of catheter-associated urinary tract infection (CA-UTI) (mean rate, 21.5 vs 5.2 infections per 1,000 catheter-days [P <.001]), the duration of urinary catheterization (mean, 11 vs 3 days [P < .001]), and the total length of hospitalization (mean, 16 vs 5 days [P < .001]). A linear relationship was seen between the monthly average duration of catheterization and the rate of CA-UTI (r = 0.89; P < .001). The intervention had the greatest impact on the rate of CA-UTI in the intensive care units (mean rate, preintervention vs postintervention, 23.4 vs 3.5 infections per 1,000 catheter-days [P = .01]). The monthly hospital costs for antibiotics to treat CA-UTI were reduced by 63% (mean, $3,739 vs $1,378 [P < .001]), and the hospitalization cost for each patient during the intervention was reduced by 58% (mean, $366 vs $154 [P < .001]). Conclusions. This study suggests that a multifaceted intervention to remind physicians to remove unnecessary urinary catheters can significantly reduced the duration of urinary catheterization and the CA-UTI rate in a hospital in a developing country.
Customer' s Adoption of Mobile-Commerce A Study on Emerging Economy

Today , mobile communication technologies provide immense additional scope for consumers' banking transactions due to their always-on functionality and the option to access bank's facilities anytime and anywhere. Mobile banking is a subset of electronic banking which underlies not only the determinants of the banking business but also the special conditions of mobile commerce. It is the latest and most innovative service offered by the banks. But not enough study has been done to known regarding how customers perceive and evaluate electronically delivered mobile banking services. The study considers five factors perceived usefulness, perceived ease of use, subjective norm, consumer awareness about mobile banking and perceived risks associated with mobile banking. This study also points out that these factors have a strong and positive effect on customers to accept mobile banking system.
Neural regulation of acetylcholinesterase mRNAs at mammalian neuromuscular synapses

We examined the role of innervation on acetylcholinesterase (AChE) gene expression within mammalian skeletal muscle fibers. First, we showed the selective accumulation of AChE mRNAs within the junctional vs extrajunctional sarcoplasm of adult muscle fibers using a quantitative reverse transcription PCR assay and demonstrated by in situ hybridization experiments that AChE transcripts are concentrated immediately beneath the postsynaptic membrane of the neuromuscular junction. Next, we determined the influence of nerve-evoked activity vs putative trophic factors on the synaptic accumulation of AChE mRNA levels in muscle fibers paralyzed by either surgical denervation or selective blockage of nerve action potentials with chronic superfusion of tetrodotoxin. Our results indicated that muscle paralysis leads to a marked decrease in AChE transcripts from the postsynaptic sarcoplasm, yet the extent of this decrease is less pronounced after tetrodotoxin inactivation than after denervation. These results suggest that although nerve-evoked activity per se appears a key regulator of AChE mRNA levels, the integrity of the synaptic structure or the release of putative trophic factors contribute to maintaining the synaptic accumulation of AChE transcripts at adult neuromuscular synapses. Furthermore, the pronounced downregulation of AChE transcripts in paralyzed muscles stands in sharp contrast to the well-documented increase in nicotinic acetylcholine receptor mRNAs under these conditions, and indicates that expression of the genes encoding these two synaptic proteins are subjected to different regulatory mechanisms in adult muscle fibers in vivo.
A New Approach to Word Sense Disambiguation

This paper presents and evaluates models created according to a schema that provides a description of the joint distribution of the values of sense tags and contextual features that is potentially applicable to a wide range of content words. The models are evaluated through a series of experiments, the results of which suggest that the schema is particularly well suited to nouns but that it is also applicable to words in other syntactic categories.
British late glacial and Holocene climatic history reconstructed from land snail assemblages

gations have enabled refinement of the stratigraphic scheme, as shells of land snails occur in quantity throughout the sequence (Preece, 1998). They provide a detailed mollusk succession from the beginning of the late glacial until the present day. The late-glacial assemblages are dominated by species of open country and marsh, but shadeintolerant species are replaced by a succession of woodland species during the early part of the Holocene. Following forest clearances during the Neolithic and Bronze Age (5000‐3000 yr B.P.), these closed forest communities show a reversion to grassland assemblages, with only minor indications of scrub (Fig. 2). A detailed chronology for this succession is provided by a series of
An in-depth spectroscopic analysis of the Blazhko star RR Lyrae - I. Characterisation of the star: abundance analysis and fundamental parameters

Aims. The knowledge of accurate stellar parameters is a keystone in several fields of stellar astrophysics, such as asteroseismology and stellar evolution. Although the fundamental parameters can be derived both from spectroscopy and multicolour photometry, the results obtained are sometimes a ected by systematic uncertainties. In this paper, we present a self-consistent spectral analysis of the pulsating star RR Lyr, which is the primary target for our study of the Blazhko e ect. Methods. We used high-resolution and high signal-to-noise ratio spectra to carry out a consistent parameter determination and abundance analysis for RR Lyr. The LLmodels code was employed for model atmosphere calculations, while SYNTH3 and WIDTH9 codes were used for line profile calculation and LTE abundance analysis. We provide a detailed description of the methodology adopted to derive the fundamental parameters and the abundances. Stellar pulsation reaches high amplitudes in RR Lyrae stars, and as a consequence the stellar parameters vary significantly over the pulsation cycle. The abundances of the star, however, are not expected to change. From a set of available high-resolution spectra of RR Lyr we selected the phase of maximum radius, at which the spectra are least disturbed by the pulsation. Using the abundances determined at this phase as a starting point, we expect to obtain a higher accuracy in the fundamental parameters determined at other phases. Results. The set of fundamental parameters obtained in this work fits the observed spectrum accurately. Through the abundance analysis, we find clear indications for a depth-dependent microturbulent velocity, that we quantified. Conclusions. We confirm the importance of a consistent analysis of relevant spectroscopic features, application of advanced model atmospheres, and the use of up-to-date atomic line data for the determination of stellar parameters. These results are crucial for further studies, e.g., detailed theoretical modelling of the observed pulsations.
Fire history of oak – pine forests in the Lower Boston Mountains , Arkansas , USA

Perspective on present day issues associated with wildland fire can be gained by studying the long-term interactions among humans, landscape, and fire. Fire frequency and extent over the last 320 years document these interactions north of the Arkansas River on the southern edge of the Lower Boston Mountains. Dendrochronological methods were used to construct three fire chronologies from 309 dated fire scars that were identified on 45 shortleaf pine (Pinus echinata) remnants. Fire frequency increased with human population density from a depopulated period (the late 1600s and early 1700s) to a peak in fire frequency circa 1880. Fire frequency then decreased as human population continued to increase. Fire frequency and human population density were positively correlated during an early period (1680–1880) with low levels of population, but negatively correlated during a later period (1881–1910) with high levels of population. We hypothesized that this difference is due to limits on fire propagation and ignition caused by land use and culture, as well as human population density. Relatively high human population densities (>5 humans/km) were associated with a peak in the maximum number of fires per decade in this highly dissected, ‘bluff and bench’ landscape compared to less dissected regions of the Ozarks. # 2002 Elsevier Science B.V. All rights reserved.
Meridional flow variability over the Nordic Seas in the Arctic oscillation framework

An anomalous recurring atmospheric circulation pattern of high relevance for the climate of the Nordic Seas and Siberia is identified. It is found as the second Empirical Orthogonal Function (EOF) of monthly winter sea level pressure (SLP) anomalies poleward of 30°N where the leading EOF is the Arctic Oscillation (AO). The most prominent centre of action of the circulation pattern is located over the Barents Region. This “Barents Oscillation” (BO) is shown to have a high temporal correlation with the sensible heat loss of the Nordic Seas (r=0.76). The BO also correlates to Eurasian surface air temperature (SAT) anomalies with r=0.72 after the AO related SAT variations are removed by means of a linear regression. Two sets of SLP composites are constructed where one is based on low and high Nordic Seas heat loss months and the other is based on warm and cold Eurasian months. Patterns reminiscent of the BO emerge in the two composites when AO related variability is removed.