120 research outputs found
New applications and developments in the neutron shielding
Shielding neutrons involve three steps that are slowing neutrons, absorption of neutrons, and impregnation of gamma rays. Neutrons slow down with thermal energy by hydrogen, water, paraffin, plastic. Hydrogenated materials are also very effective for the absorption of neutrons. Gamma rays are produced by neutron (radiation) retention on the neutron shield, inelastic scattering, and degradation of activation products. If a source emits gamma rays at various energies, high-energy gamma rays sometimes specify shielding requirements. Multipurpose Materials for Neutron Shields; Concrete, especially with barium mixed in, can slow and absorb the neutrons, and shield the gamma rays. Plastic with boron is also a good multipurpose shielding material. In this study; new applications and developments in the area of neutron shielding will be discussed in terms of different materials
Differences and Similarities across Four Countries
Cyberbullying is a ubiquitous topic when considering young people and internet
and communication technologies (ICTs). For interventional purposes, it is
essential to take into account the perspective of adolescents. This is the
reason why our main focus is (1) investigating the role of different criteria
in the perceived severity of cyberbullying incidents, and (2) examining the
differences between countries in the perceived severity of cyberbullying. The
sample consisted of 1,964 adolescents (48.2% girls) from middle and high
schools of four different countries, i.e., Estonia, Italy, Germany, and
Turkey. The participants' age ranged from 12 to 20 years old with a mean age
of 14.49 (SD = 1.66) years. To assess perceived severity, participants rated a
set of 128 scenarios, which systematically included one or more of five
criteria (intentionality, repetition, imbalance of power, public vs. private,
and anonymity) and represented four types of cyberbullying behaviors
(WrittenâVerbal, Visual, Exclusion, Impersonation). The role of different
criteria was analyzed using the Exploratory Structural Equation Modeling
(ESEM). Results showed a similar structure across the four countries
(invariant except for the latent factors' means). Further, criteria of
imbalance of power and, to a lesser extent, intentionality, anonymity, and
repetition always in combination, were found to be the most important criteria
to define the severity of cyberbullying. Differences between countries
highlighted specific features of Turkish students, who perceived all scenarios
as more severe than adolescents from other countries and were more sensitive
to imbalance of power. German and Italian students showed an opposite
perception of anonymity combined with intentionality. For Italian
participants, an anonymous attack was less threatening than for participants
of other countries, whereas for German students anonymity caused more
insecurity and fear. In addition, Italian adolescents were more perceptive of
the criterion of intentionality. Finally, Estonian adolescents did not show
strong differences in their factor scores compared to adolescents from the
other countries
Ambulatory blood pressure monitoring and renal functions in children with a solitary kidney
The aim of this study is to investigate the blood pressure (BP) profile, microalbuminuria, renal functions, and relations with remaining normal kidney size in children with unilateral functioning solitary kidney (UFSK). Sixty-six children with UFSK were equally divided into three groups: unilateral renal agenesis (URA), unilateral atrophic kidney (UAK), and unilateral nephrectomy (UNP). Twenty-two age-, weight-, and height-matched healthy children were considered as a control group. The serum creatinine level and first-morning urine microalbumin and creatinine concentrations were determined by the standard methods. Also, the BP profile was determined by ambulatory blood pressure monitoring (ABPM). We found that the serum creatinine level was higher and creatinine clearance was lower in each patient groups compared to those of the control group (pâ<â0.05). Compared with the controls, each group of patients had mean office, 24-h, daytime, and night-time systolic and diastolic BP values similar to those of the controls (pâ>â0.05). An inverse correlation was found between the renal size standard deviation scores (SDS) of normal kidneys and 24-h systolic and diastolic BP load SDS in all of the patients (pâ<â0.05; râ=ââ0.372, râ=ââ0.295, respectively). The observed relationship between renal size SDS and 24-h mean arterial pressure (MAP), systolic and diastolic BP load SDS suggests that children with UFSK should be evaluated by using ABPM for the risk of hypertension
Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-Ï auto-Abs in children
We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2
An optical search for Supernova Remnants in NGC 3184 and NGC 2903
In this work, we present the results of an optical search for Supernova Remnants (SNRs) in the spiral galaxies NGC3184 and NGC2903. The SNR identification technique consisted of constructing continuum-subtracted H-alpha and [SII] lambda lambda 6716,6731 images and then using [SII] / H-alpha ratios obtained from the image. The SNR candidates are normally identified as nebulae that have [SII] / H-alpha ratios > 0.4 compared with HII regions < 0.2. Our list of candidates contains 29 objects in NGC3184 and 10 objects in NGC2903. We compare our SNR candidate list against the existing X-ray and radio observations of the two galaxies. Knowing the positions of the SNRs, we can compare their distributions relative to FIII regions and spiral arms. From these distributions, we can investigate such properties of possible SNR progenitors as their parent stellar populations and supernova types. These observations were performed with the 1.5m Russian-TurkishTelescope (RTT) Spectrograph TFOSC's (TUG Faint Object Spectrograph and Camera) CCD imaging system using narrowband interference filters at Turkish National Observatory (TUG) in March 2006
- âŠ