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Despite the rigorous emission control measures in the ferroalloy industry, there are still emissions of dust during the production of various alloys. Dust particles were collected from laboratory scale processes where oxide particulate matter was formed from liquid silicon (metallurgical grade). The dust was produced in a dry air atmosphere to mimic industrial conditions. To investigate possible effects of ultrafine dust on the central nervous system, a human astrocytic cell line was employed to investigate inflammatory effects of particles as astrocytes play a number of active and neuron supporting roles in the brain. Toxicity on the astrocytes by amorphous silica generated in laboratory scale was compared to crystalline macro-sized silica using several doses to determine toxicological dose response curves. The cell viability experiments indicated that low particle doses of amorphous silica induced a small nonsignificant reduction in cell viability compared to crystalline silica which led to increased levels of toxicity. The gene expression of amyloid precursor protein (APP), a biomarker of neurodegenerative disease, was affected by particle exposure. Furthermore, particle exposure, in a dose-and time-dependent manner, affected the ability of the cells to communicate through gap junction channels. In conclusion, in vitro studies using low doses of particles are important to understand mechanisms of toxicity of occupational exposure to silica particles. However, these studies cannot be extrapolated to real exposure scenarios at work place, therefore, controlling and keeping the particle exposure levels low at the work place, would prevent potential negative health effects.

This work investigates the influence of meteoric smoke particles (MSP) on the charge balance in the D-region ionosphere. Both experimental in situ measurements and a one-dimensional ionospheric model reveal a clear impact of MSP on the ionospheric composition of the D-region. The study reviews rocket-borne in situ measurements of electron and positive ion density, which show a distinct deficit of electrons in comparison to positive ions between 80 and 95 km. This deficit can be explained by the ambient negatively charged MSP measured simultaneously with a Faraday cup. The influence of MSP on the D-region charge balance is addressed with a simplified ionospheric model with only six components, i.e. electrons, positive and negative ions and neutral and charged MSP (both signs). The scheme includes reactions of plasma captured by MSP and MSP photo reactions as well as the standard ionospheric processes, e.g. ion-ion recombination. The model shows that the capture of plasma constituents by MSP is an important process leading to scavenging of electrons. Since Faraday cup measurements are biased towards heavy MSP because of aerodynamical filtering, we have applied an estimate of this filter on the modelled MSP densities. By doing that, we find good qualitative agreement between the experimental data and our model results. In addition, the model study reveals an increase of positive ions in the presence of MSP. That is primarily caused by the reduced dissociative recombination with electrons which have been removed from the gas phase by the MSP.

We report Geminid meteor head echo observations with the high-power large-aperture (HPLA) Shigaraki middle and upper atmosphere (MU) radar in Japan (34.85° N, 136.10° E). The MU radar observation campaign was conducted from 13 December 2010, 08:00 UTC to 15 December, 20:00 UTC and resulted in 48 h of radar data. A total of ~ 270 Geminids were observed among ~ 8800 meteor head echoes with precisely determined orbits. The Geminid head echo activity is consistent with an earlier peak than the visual Geminid activity determined by the International Meteor Organization (IMO). The observed flux of Geminids is a factor of ~ 3 lower than the previously reported flux of the 2009 Orionids measured with an identical MU~radar setup. We use the observed flux ratio to discuss the relation between the head echo mass–velocity selection effect, the mass distribution indices of meteor showers and the mass threshold of the MU radar.

We have developed an automated analysis scheme for meteor head echo observations by the 46.5 MHz Middle and Upper atmosphere (MU) radar near Shigaraki, Japan (34.85° N, 136.10° E). The analysis procedure computes meteoroid range, velocity and deceleration as functions of time with unprecedented accuracy and precision. This is crucial for estimations of meteoroid mass and orbital parameters as well as investigations of the meteoroid-atmosphere interaction processes. In this paper we present this analysis procedure in detail. The algorithms use a combination of single-pulse-Doppler, time-of-flight and pulse-to-pulse phase correlation measurements to determine the radial velocity to within a few tens of metres per second with 3.12 ms time resolution. Equivalently, the precision improvement is at least a factor of 20 compared to previous single-pulse measurements. Such a precision reveals that the deceleration increases significantly during the intense part of a meteoroid's ablation process in the atmosphere. From each received pulse, the target range is determined to within a few tens of meters, or the order of a few hundredths of the 900 m long range gates. This is achieved by transmitting a 13-bit Barker code oversampled by a factor of two at reception and using a novel range interpolation technique. The meteoroid velocity vector is determined from the estimated radial velocity by carefully taking the location of the meteor target and the angle from its trajectory to the radar beam into account. The latter is determined from target range and bore axis offset. We have identified and solved the signal processing issue giving rise to the peculiar signature in signal to noise ratio plots reported by Galindo et al. (2011), and show how to use the range interpolation technique to differentiate the effect of signal processing from physical processes.

Two case studies of upper mesospheric and lower thermospheric (UMLT) high-latitude effects of solar X-ray flares are presented. Sodankylä Ion-neutral Chemistry Model (SIC) electron density profiles agree with D-region EISCAT and riometer observations, provided that the profiles of the most variable ionisable component, nitric oxide, are adjusted to compensate for NOx production during preceding geomagnetically active periods. For the M6-class flare of 27 April 2006, following a quiet period, the agreement with cosmic noise absorption observed by the Sodankylä riometers was within reasonable limits without adjustment of the [NO] profile. For the major (X17-class) event of 28 October 2003, following high auroral activity and solar proton events, the NO concentration had to be increased up to on the order of 108 cm−3 at the D-region minimum. Thus [NO] can in principle be measured by combining SIC with observations, if the solar spectral irradiance and particle precipitation are adequately known. As the two case events were short and modelled for high latitudes, the resulting neutral chemical changes are insignificant. However, changes in the model ion chemistry occur, including enhancements of water cluster ions.

A new incoherent scatter (IS) diagnostic technique for the actively heated D-region ionosphere is presented. In this approach, an exponential autocorrelation function (ACF) was fitted to the data by using a Markov Chain Monte Carlo (MCMC) inversion and the Sodankylä Ion Chemistry model (SIC). The method was applied for a set of combined EISCAT heating and VHF radar experiments carried out in November 2006. A newly designed radar experiment, sippi, based on optimised phase codes and direct sampling of the transmitted and the received IS signal, was used to produce ACF estimates of the target plasma. Systematic features associated with the heating were found by comparing the mean ACFs corresponding to heated and unheated periods. However, the data analysis revealed reasonable electron temperature estimates at the altitudes of the expected maximum effect (70–75 km) only in three cases out of six, corresponding to the highest signal-to-noise ratio (SNR) conditions. In two of these cases, the electron temperature was increased by a factor of 5 to 7, which is in a good agreement with the theoretical heating modelling. In the case of the first presented data example, the model overestimates the effect. These are the first successful IS observations of the HF-induced maximum electron temperature enhancements in the D-region ionosphere.

The EISCAT UHF system has the unique capability to determine meteor vector velocities from the head echo Doppler shifts measured at the three sites. Since even meteors spending a very short time in the common volume produce analysable events, the technique lends itself ideally to mapping the orbits of meteors arriving from arbitrary directions over most of the upper hemisphere. A radar mode optimised for this application was developed in 2001/2002. A specially selected low-sidelobe 32-bit pseudo-random binary sequence is used to binary phase shift key (BPSK) the transmitted carrier. The baud-length is 2.4 μs and the receiver bandwidth is 1.6 MHz to accommodate both the resulting modulation bandwidth and the target Doppler shift. Sampling is at 0.6 μs, corresponding to 90-m range resolution. Target range and Doppler velocity are extracted from the raw data in a multi-step matched-filter procedure. For strong (SNR>5) events the Doppler velocity standard deviation is 100–150 m/s. The effective range resolution is about 30 m, allowing very accurate time-of-flight velocity estimates. On average, Doppler and time-of-flight (TOF) velocities agree to within about one part in 103. Two or more targets simultaneously present in the beam can be resolved down to a range separation

In this work we give a review of the meteor head echo observations carried out with the tristatic 930 MHz EISCAT UHF radar system during four 24 h runs between 2002 and 2005 and compare these with earlier observations. A total number of 410 tristatic meteors were observed. We describe a method to determine the position of a compact radar target in the common volume monitored by the three receivers and demonstrate its applicability for meteor studies. The inferred positions of the meteor targets have been utilized to estimate their velocities, decelerations and directions of arrival as well as their radar cross sections with unprecedented accuracy. The velocity distribution of the meteoroids is bimodal with peaks at 35–40 km/s and 55–60 km/s, and ranges from 19–70 km/s. The estimated masses are between 10−9–10−5.5 kg. There are very few detections below 30 km/s. The observations are clearly biased to high-velocity meteoroids, but not so biased against slow meteoroids as has been presumed from previous tristatic measurements. Finally, we discuss how the radial deceleration observed with a monostatic radar depends on the meteoroid velocity and the angle between the trajectory and the beam. The finite beamwidth leads to underestimated meteoroid masses if radial velocity and deceleration of meteoroids approaching the radar are used as estimates of the true quantities in a momentum equation of motion.

In this paper we study the effect of artificial HF heating on cosmic radio noise absorption in the D-region ionosphere. The effect has earlier been studied theoretically in idealised cases and without experimental verification. Here we present a 3-dimensional modelling of the effect, taking into account the directivity patterns of the vertical beam of the EISCAT Heater at Tromsø, Norway, and the intersecting beam of the IRIS imaging riometer at Kilpisjärvi, Finland. The heater-induced enhancement of cosmic radio noise absorption at the IRIS frequency (38.2 MHz) is estimated to be between 0.02 dB and 0.05 dB in the most representative model cases. However, a statistical study of IRIS data from a selected set of heating experiments carried out during the years 1994–2004 shows that the median effect is between 0.002 dB and 0.004 dB, i.e. an order of magnitude less than theoretically predicted. This indicates that the actual HF heating effect at D-region altitudes is substantially overestimated by the present theory.

Slider scales (or, visual analog scales) are becoming increasingly popular in web-based surveys. These psychometric response scales utilize Likert-type items in which respondents select a point along a line labelled with bipolar endpoints to indicate their preference or agreement with a statement. This article is a response to an article that appeared earlier in the Journal of Research Practice where the writers treated Likert-type data as interval-level measurements. The authors of this response article contend that it is erroneous to suppose the data obtained by visual analog scales to be quantitative and continuous (on an interval scale) when, in fact, these are discreet data (on an ordinal scale), which are essentially qualitative. Qualitative data are not quantitative and no means of analysis can make it so.

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Istraživanje je izvedeno na 300 adolescenata s područja Županije varaždinske u dobi od 14 do 18 godina. Prvu eksperimentalnu grupu činilo je 100 adolescenata, koji su kao maloljetni delinkventi zbog kaznenih djela prijavljeni državnom odvjetniku za mladež. Drugu eksperimentalnu grupu činilo je 100 adolescenata na čiju su štetu počinjena kaznena djela. Kontrolnu grupu činilo je 100 adolescenata, koji nikad nisu bili predmet policijskog postupanja. U prikupljanju podataka korištena je metoda usmjerenog intervjua, uz pomoć inicijalnog lista za prikupljanje osnovnih sociodemografskih i socioekonomskih podataka te podaci o asocijalnom ponašanju ispitanika i članova njihovih obitelji. Svi su ispitanici bili ispitivani testom Profila indeks emocija (PIE) koji daje podatke o osam emocija. Istraživanjem je dokazano da procjenjivanjem crta ličnosti između delinkvenata u adolescenciji i adolescenata na čiju su štetu počinjena kaznena djela nema znatnih statističkih razlika. Znatna statistička razlika postoji samo u crti ličnosti samozaštite. Bitne razlike među grupama nisu nađene, niti u podacima o socioekonomskom i obiteljskom statusu, niti u podacima o prisustvu asocijalnih načina ponašanja ispitanika i članova njihovih obitelji.

The upper mesosphere and lower thermosphere, or ionospheric D region, is an atmospheric layer which is difficult to access experimentally. A useful method that also has a large potential for further studies is artificial heating of electrons by means of powerful radio transmitters. Here we estimate the effect of D-region heating for a few typical cases of high electron density – daylight, typical auroral electron precipitation, and a solar proton event – by coupling a model of RF electron heating to the Sodankylä Ion Chemistry (SIC) model. The predicted effects are among others an increase in the ratio of the concentration of negative ions to that of free electrons, and an increase in the absorption of cosmic noise as measured by riometers. For the model runs presented in this paper we have calculated the absorption for the frequency (38.2MHz) of the IRIS imaging riometer in Kilpisjärvi, Finland, as observing the ionosphere above the EISCAT Heater in Tromsø, Norway. The predicted enhancements of the absorption are 0.2–0.8dB, an effect which is clearly detectable. Keywords. Ionosphere (Active experiments; Ion chemistry and composition; Wave propagation)

The ionospheric electron gas can be heated artificially by a powerful radio wave. According to our modeling, the maximum effect of this heating occurs in the D-region where the electron temperature can increase by a factor of ten. Ionospheric plasma parameters such as Ne, Te and Ti are measured by EISCAT incoherent scatter radar on a routine basis. However, in the D-region the incoherent scatter echo is very weak because of the low electron density. Moreover, the incoherent scatter spectrum from the D-region is of Lorentzian shape which gives less information than the spectrum from the E- and F-regions. These make EISCAT measurements in the D-region difficult. A combined EISCAT VHF-radar and heating experiment was carried out in November 1998 with the aim to measure the electron temperature increase due to heating. In the experiment the heater was switched on/off at 5 minute intervals and the integration time of the radar was chosen synchronously with the heating cycle. A systematic difference in the measured autocorrelation functions was found between heated and unheated periods.Key words: Ionosphere (active experiments; plasma temperature and density; wave propagation)

In the study programme of chemical technology at Centria University of Applied Sciences, project studies have been designed since 2011, and evaluation of the progress was done for the first time in spring 2012. Chemistry Project course is based on the methods of Problem Based Learning (PBL) and Project Oriented Problem Based Learning (POPBL). The aim is to train self-directed experts of the field with teamwork and collaboration skills.

The aim of this paper is to investigate household spending by income deciles. Only the most important one among the expenditure categories was considered, food and non-alcoholic beverages. Research and analysis were based on the results of the Questionnaire on Household Expenditure in the Republic of Croatia. Adequate mathematical and statistical models of expenditure for food and non-alcoholic beverages by income deciles were established. The defined models were used in further research to calculate the coefficient of elasticity. The research showed that expenditure for food and non-alcoholic beverages is non-elastic, thus confirming the first Engel’s law. The obtained results can be used in planning household expenditure also in future periods, considering the fact that the model of expenditure by income deciles referring to the period 200 – 2009 was developed. A model for measuring elasticity was constructed as well. It refers to a 10-year period and can be used to forecast future coefficients of elasticity.

Objective: To study neurodevelopmental outcome in a two year cohort of extremely low birthweight (ELBW) infants at 18 months corrected age, to compare the development of the ELBW infant subcohort [...]

Obtaining vascular access in the pediatric population can be challenging, with insertion success rates varying widely based on patient and practitioner associated factors. Difficulty establishing peripheral intravenous access can delay treatment, which can be detrimental in emergent situations. Nurses who are trained in vascular access yield a much higher first attempt success rate, which decreases resource utilization, time to intervention, and complication rate. Fewer insertion attempts can also result in improved outcomes including decreased length of stay and better patient and family perception of pain. The Vascular Access Service at our institution developed an extensive training program, which included three stages: didactic learning, simulation training, and insertion validation. During the first three months of 2020, there were 54 ultrasound-guided peripheral IVs placed in the pediatric intensive care units, 100% of which were placed by the vascular access service. In the first three months of 2021, 63 ultrasound-guided peripheral IVs were placed, 100% of which were placed by pediatric intensive care unit nurses. Of those placed by pediatric intensive care unit nurses, 52 (82.5%) were placed following their ultrasound-guided peripheral IV training. First time insertion success rates were 86.5% with competency in a diverse patient population of widely varying ages. Programs that include repeated simulation experiences may facilitate greater learning and thus increase the confidence of the nurses trained. Improving staff skills for vascular access has promoted independent bedside practice and contributed to a culture of quality and safety for the pediatric patient population. • Difficult IV access is a common problem in the pediatric population. • The Vascular Access Service created a three-stage training program for ICU nurses. • First time insertion success rates were 86.5% in pediatric patients after training. [ABSTRACT FROM AUTHOR]

Background: Mild Cognitive Impairment (MCI) is one of the early predictors of Alzheimer's disease (AD) and dementia. Assessing comorbidities associated with an MCI diagnosis is crucial not only for diagnostic accuracy but also for understanding the role of comorbidities for evident cognitive impairment. In this study we investigated the association between MCI (amnestic and/or non‐amnestic) and primary comorbidities of hypertension (HTN), hyperlipidaemia (HLD), and Diabetes Mellitus (DM). Methods: We recruited 116 community‐dwelling older African American adults with subjective complaints (103 females, 13 males, mean age = 73.93, range = 65‐91) through the Wayne State Institute of Gerontology and Michigan Alzheimer's Disease Research Center. Participants were consensus diagnosed as 57 healthy controls (HC), 32 amnestic MCI (aMCI), and 27 nonamnestic MCI (naMCI) based on NAAC Unified Data Set3 protocol. NIH Toolbox‐Cognition battery (NIHTB‐C) also was administered, but not used for consensus. Results: Across all the participants, UDS3 forms noted 69% with hypertension (HTN), 56% hyperlipidaemia (HLD), and 28% Type II Diabetes. Among the normal group: 65% had HTN, 51% had HLD, and 28% had DM. Among those diagnosed with aMCI: 66% had HTN, 53% had HLD, and 34% had DM. Among naMCI: 81% had HTN, 63% had HLD, and 22% had DM. Comorbidities did not differ significantly across diagnostic groups. Regarding NIHTB‐C, significant ANOVA interactions did show that aMCI and naMCI with DM were lower in Fluid Intelligence than scores for controls with DM (p =.017). Also, as compared to controls with HTN, naMCI with HTN were lower on Fluid Intelligence (p =.024). Conclusion: Our findings did not demonstrate differences in cardiovascular‐ or diabetes‐related comorbidities across MCI groups and controls in this group of community‐dwelling African Americans. However, DM and HTN, but not HLD, did affect the relationship among the diagnostic groups for fluid intelligence, a summary measure of higher cognitive functioning. This suggests that comorbid medical factors can affect cognitive performance, particularly for MCI groups. Further research is needed to fully understand the scope of risk factors influencing cognitive decline in African Americans. Further analyses will assess relationships between cognitive diagnoses, race, health conditions, and demographic risk factors. [ABSTRACT FROM AUTHOR]