Design of a Novel Antenna Array Beamformer Using Neural Networks Trained by Modified Adaptive Dispersion Invasive Weed Optimization Based Data

A new antenna array beamformer based on neural networks (NNs) is presented. The NN training is performed by using optimized data sets extracted by a novel Invasive Weed Optimization (IWO) variant called Modified Adaptive Dispersion IWO (MADIWO). The trained NN is utilized as an adaptive beamformer that makes a uniform linear antenna array steer the main lobe towards a desired signal, place respective nulls towards several interference signals and suppress the side lobe level (SLL). Initially, the NN structure is selected by training several NNs of various structures using MADIWO based data and by making a comparison among the NNs in terms of training performance. The selected NN structure is then used to construct an adaptive beamformer, which is compared to MADIWO based and ADIWO based beamformers, regarding the SLL as well as the ability to properly steer the main lobe and the nulls. The comparison is made considering several sets of random cases with different numbers of interference signals and different power levels of additive zero-mean Gaussian noise. The comparative results exhibit the advantages of the proposed beamformer

Using Social Network Analysis to gain insight into social creativity while designing digital mathematics books

Analysing the processes and products of creativity to better understand and support individuals and teams, is a difficult and elusive challenge despite years of research in creativity. In this article, we are particularly interested in social creativity in communities of interest. Building on Guilford's classic model of Divergent Thinking of fluency, flexibility, originality and elaboration, we employ Social Network Analysis to model the creative design process. The creative process in the current study takes place in a technological environment called the ‘MC-squared platform’, in which members of a community of interest collaborate in a social, co-creative process for designing digital, mathematical textbooks. Both the technological environment and the methodology are exemplified through two case examples, one on the design process of a digital book about a bioclimatic amusement park and one on the design process of a digital book about fractions. We conclude that, for these examples, both the technological tool and the data analysis approach provide insight into the social creativity process of the community of interest

Effect of dentin matrix components on the mineralization of human mesenchymal stromal cells

In teeth with an injured pulp, dentin matrix orchestrates hard tissue repair through the release of dentin extracellular matrix components (dEMCs). dEMCs regulate the differentiation of resident mesenchymal stromal cells (MSCs), thereby affecting mineral deposition. In this study, we show that low-concentration solubilized dEMCs in osteogenic cultures of human umbilical cord mesenchymal stromal cells (UC-MSCs) and dental pulp stromal cells (DPSCs) enhanced mineral deposition, while adipose stromal cells (ASCs) were barely affected. Interestingly, UC-MSCs displayed significantly greater hydroxyapatite formation compared with DPSCs. UC-MSCs and DPSCs showed a dose-dependent viability and proliferation, whereas proliferation of ASCs remained unaffected. Qualitative analysis of the dEMC-supplemented osteogenic cultures through scanning electron microscopy demonstrated differences in the architecture of the deposited mineralized structures. Large-sized mineral accretions on a poorly organized collagen network were the prominent feature of UC-MSC cultures, while mineral nodules interspersed throughout a collagen mesh were observed in the respective DPSC cultures. The ability of dEMCs to induce mineralization varies between different human MSC types in terms of total mineral formation and architecture. Mineral formation by UC-MSCs exposed to low-concentration dEMCs proved to be the most efficient and therefore could be considered a promising combination for mineralized tissue engineering. Impact Statement This research has been conducted with the aim to contribute to the development of treatment modalities for the reconstruction of lost/damaged mineralized tissues. Currently, determining the most appropriate stromal cell population and signaling cues stands at the core of developing effective treatments. We provide new insights into the effect of innate inductive cues found in human dentin matrix components, on the osteogenic differentiation of various human stromal cell types. The effects of dentin extracellular matrix components on umbilical cord mesenchymal stromal cells have not been investigated before. The findings of this study could underpin translational research based on the development of techniques for mineralized tissue engineering and will be of great interest for the readership of Tissue Engineering Part A

Learning Programming with Educational Robotics: Towards an Integrated Approach

Despite the fact that it has been a few years since robotics entered the school and offered new learning opportunities, educational robotics usually is offered in the context of extra-curricular activity (e.g. a “club”) which addresses a limited number of students and participation is based on student personal interest. In this paper we explore the potential of ER when it is integrated in the typical school curriculum. In the study we report here, we integrated ER in the computer science curriculum and all students of a 9th grade class engaged with robotics activities. The rationale underlying the study is that robotics can be used as a medium to motivate students in engaging with programming and support them to negotiate real life problems. Analysis of the data collected, indicate that ER when integrated with the computer science curriculum, can create a rich learning environment where programming is contextualized and students are highly motivated to engage and negotiate important STEM concepts

Two-Stage, 90-GHz, Low-Noise Amplifier

A device has been developed for coherent detection of the polarization of the cosmic microwave background (CMB). A two-stage amplifier has been designed that covers 75-110 GHz. The device uses the emerging 35-nm InP HEMT technology recently developed at Northrop Grumman Corporation primarily for use at higher frequencies. The amplifier has more than 18 dB gain and less than 35 K noise figure across the band. These devices have noise less than 30 K at 100 GHz. The development started with design activities at JPL, as well as characterization of multichip modules using existing InP. Following processing, a test campaign was carried out using single-chip modules at 100 GHz. Successful development of the chips will lead to development of multichip modules, with simultaneous Q and U Stokes parameter detection. This MMIC (monolithic microwave integrated circuit) amplifier takes advantage of performance improvements intended for higher frequencies, but in this innovation are applied at 90 GHz. The large amount of available gain ultimately leads to lower possible noise performance at 90 GHz

Investigating the effect of child maltreatment on early adolescent peer-on-peer sexual aggression: testing a multiple mediator model in a non-incarcerated sample of Danish adolescents

Objective: The aim of the present study was to investigate the relationship between child maltreatment and severe early adolescent peer-on-peer sexual aggression, using a multiple mediator model. Methods: The study comprised 330 male Grade 9 students with a mean age of 14.9 years (SD=0.5). Results: Estimates from the mediation model indicated significant indirect effects of child physical abuse on sexual aggression via peer influence and insecure-hostile masculinity. No significant total effect of child sexual abuse and child neglect on sexual aggression was found. Conclusions: Findings of the present study identify risk factors that are potentially changeable and therefore of value in informing the design of prevention programs aiming at early adolescent peer-on-peer sexual aggression in at-risk youth

Secreted products of oral bacteria and biofilms impede mineralization of apical papilla stem cells in TLR-, species-, and culture-dependent fashion

Regenerative endodontics exploits the mineralization potential of stem cells from the apical papilla (SCAPs) in order to promote root maturation of permanent immature teeth. SCAPs may encounter post-disinfection residual bacteria either in planktonic or in biofilm growth mode. Bacterial components bind to Toll-like receptors (TLRs) and trigger pro-inflammatory responses. We hypothesized that biofilm-triggered TLR activation affects the mineralization potential of human SCAPs. SCAPs were challenged with conditioned media derived from standardized dual-species biofilms and planktonic bacterial cultures and their inflammatory status and mineralization capacity were studied. Bacterial products from both growth modes (planktonic vs. biofilm) compromised cell viability, proliferation and mineralization capacity of SCAPs, but in a species- and growth mode-dependent fashion. While TLR4 expression remained unaffected, TLR2 expression was upregulated coinciding with a pro-inflammatory activation of SCAPs. Moreover, TLR and its downstream TGF-β-associated kinase (TAK1) appeared to be blocking mineralization, as inhibition of these factors restored it. In conclusion, bacterial products promoted the pro-inflammatory status and inhibited mineralization of human SCAPs in a TLR-, species-, and culture-dependent fashion. TLR2 emerged as the pivotal mediator of these responses and further research is warranted towards the judicious manipulation of SCAPs in order to modify the untoward events of TLR-priming and signaling

Coital Experience Among Adolescents in Three Social-Educational Groups in Urban Chiang Mai, Thailand

This article compares coital experience of Chiang Mai 17–20-year-olds who were: (1) out-of-school; (2) studying at vocational schools; and (3) studying at general schools or university. Four-fifths, two-thirds and one-third, respectively, of males in these groups had had intercourse, compared to 53, 62 and 15 per cent of females. The gender difference for general school/university students, but not vocational school students, probably reflects HIV/AIDS refocusing male sexual initiation away from commercial sex workers. Vocational school females may have been disproportionately affected. Loss of virginity was associated, for both sexes, with social-educational background and lifestyle, and was less likely in certain minority ethnic groups. Among males, it was also associated with age and parental marital dissolution, and among females, with independent living and parental disharmony. Within social-educational groups, lifestyle variables dominated, but among general school/university students, parental marital dissolution (for males) and disharmony (for females) were also important, and Chinese ethnicity deterred male sexual experimentation

Changes in Inflammatory Response after Endovascular Treatment for Type B Aortic Dissection

This present study aims to investigate the changes in the inflammatory markers after elective endovascular treatment of Type B aortic dissection with aneurysm, as related to different anatomical features of the dissection flap in the paravisceral perfusion. Consecutive patients with type B aortic dissections with elective endovascular stent graft repair were recruited and categorized into different groups. Serial plasma levels of cytokines (Interleukin-1β, -6, -8, -10, TNF-α), chemokines (MCP-1), and serum creatinine were monitored at pre-, peri- and post-operative stages. The length of stent graft employed in each surgery was retrieved and correlated with the change of all studied biochemical parameters. A control group of aortic dissected patients with conventional medication management was recruited for comparing the baseline biochemical parameters. In total, 22 endovascular treated and 16 aortic dissected patients with surveillance were recruited. The endovascular treated patients had comparable baseline levels as the non-surgical patients. There was no immediate or thirty day-mortality, and none of the surgical patients developed post-operative mesenteric ischaemia or clinically significant renal impairment. All surgical patients had detectable pro-inflammatory mediators, but none of the them showed any statistical significant surge in the peri-operative period except IL-1β and IL-6. Similar results were obtained when categorized into different groups. IL-1β and IL-6 showed maximal levels within hours of the endovascular procedure (range, 3.93 to 27.3 higher than baseline; p = 0.001), but returned to baseline 1 day post-operatively. The change of IL-1β and IL-6 at the stent graft deployment was statistically greater in longer stent graft (p>0.05). No significant changes were observed in the serum creatinine levels. In conclusion, elective endovascular repair of type B aortic dissection associated with insignificant changes in inflammatory mediators and creatinine. All levels fell toward basal levels post-operatively suggesting that thoracic endovascular aortic repair is rather less aggressive with insignificant inflammatory modulation