Reflections on iCODE: using web technology and hands-on projects to engage urban youth in computer science and engineering

More than 200 middle school and high school students from underserved urban communities in Boston, Lowell, and Lawrence, Massachusetts, participated in after-school and summer enrichment programs over a three-year period, using hands-on learning materials and web resources to complete hands-on microcontroller-based projects. Program content was based on a suite of robotics and electronics kits developed by the University of Massachusetts Lowell and Machine Science Inc., together with on-line instructions, a web-based programming tool, and a shared electronic portfolio of student projects. Participating students worked with classroom teachers and undergraduate mentors to complete a series of projects, and took part each year in a non-competitive robotics exhibition and a competitive robot sumo tournament. Goodman Research Group assessed learning outcomes and attitudinal changes using a variety of measures, including observations of program sessions, group interviews with participating students, pre- and post-program student surveys, and educator feedback. The program was found to effectively engage participants, give them real engineering and programming skills, improve their attitudes toward science, technology, engineering, and mathematics (STEM) subjects, and increase their interest in STEM career pathways. These results are presented, along with lessons learned from the program implementation, technology development, and evaluation.     

Content analysis and stability evaluation of selected commercial preparations of St. John's wort

Content analysis and stability studies were performed for the commercial products of St. John's wort. Six marketed formulations were analyzed for their hypericin and pseudohypericin content. These products were standardized to contain 0.3% hypericin. Results revealed total hypericin as 7.72-38.57% of the labeled claim with varying concentrations of pseudohypericin. Stability studies were carried out under three different storage conditions: 1) 25 ± 2°C, 60 ± 5%RH for six months, 2) 40 ± 2°C, 75 ± 5%RH for six months, and 3) 50°C for one month. Tablet formulations were also analyzed for their hardness and friability. Stability studies revealed significant decrease in the content of the marker compounds with time.     

Fair Adaptive Cross-Layer Resource Allocation Scheme for IEEE 802.16 Broadband Wireless Networks

In a WiMAX network, the Medium Access Control (MAC) protocol deals with resource allocation to different types of traffic. The key components that ensure Quality of Service (QoS) guarantees in a WiMAX network include Call Admission Control (CAC), Bandwidth and Burst allocation. In this Paper, a Cross-layer framework is designed to efficiently allocate resources to various classes of traffic. CAC and Bandwidth allocation are dealt in the MAC layer, while Burst allocation in the PHYsical layer. The predominant goal of this work is to reduce delay and Information Element (IE) overheads by efficiently utilizing the available frame space. The History based CAC (HCAC) proposed in this paper deals with call acceptance based on the Contention Window (CW) values. The History based Bandwidth Allocation (HBA) scheme deals with allocating bandwidth based on Consumption and Equity measures. The proposed tightly coupled Delay Tolerance based Scheduler (DTS) and Bucket based Burst Allocator (BBA) allocate resources by prioritizing flows with least delay tolerance. It is seen that the proposed schemes offer better performance in contrast to the existing benchmarked schemes in terms of Throughput, Average Delay and Packet Loss Ratio (PLR).

     

Structural,optical, mechanical,electrical, and antimicrobial activities of L-Glutamine Barium Acetate (LGBA) single crystal for biological,optical and photonic applications

Journal of Materials Science: Materials in Electronics - The most generally used slow evaporation technique at ambient temperature is used to develop L-glutamine barium acetate (LGBA) materials for...     

Reduced nitrate concentrations in shallow ground water under a non-fertilised grass buffer strip

In this paper the suitability of a buffer strip to reduce nitrate concentrations in the upper groundwater was tested for a sandy arable soil in The Netherlands during two consecutive leaching seasons. The bufferstrip was a 3.5 m wide unfertilised grass strip adjacent to a ditch on an arable field. In total 24 groundwater wells were installed in 4 transects perpendicular to the ditch to determine Cl, NO₃ and δ¹⁵N concentrations. Piezometers were installed to assess the groundwater flow, which was in the direction of the ditch with small downward leakage across a peat layer at about 3 m depth. Nitrogen was dominantly present as nitrate (NO₃). The NO₃-N concentrations under the bufferstrip were significantly lower than under the adjacent arable field. The lower concentrations were due to dilution, uptake by grass and denitrification. Nitrate was actively removed in the bufferstrip, since the Cl/NO₃ ratios were higher in the bufferstrip than in the remainder of the field. Furthermore, δ¹⁵N data indicated that denitrification occurred in the groundwater and increased with decreasing distance to the ditch. NO₃-N loads to the ditch were estimated at 8.5 kg ha⁻¹yr⁻¹, which is relatively low for this area. We can, however, not determine whether these relatively low NO₃-N loads were causally related to the reduced NO₃-N concentrations in the bufferstrip. Nevertheless, the results of the present study are promising and justify additional research on the efficiency of bufferstrips to reduce NO₃ concentrations in shallow groundwater, and subsequently reduce NO₃ loading of surface water, under Dutch conditions.     

Content-Based Image Recognition and Tagging by Deep Learning Methods

Wireless Personal Communications - Deep learning techniques is growing wider day by day in the process of Content based Image retrieval (CBIR). The recognition of the image is based on its shape,...     

从常规的定量聚合酶链反应（qPCR）实验到快速qPCR实验的转变

如今,不用购买新型的qPCR仪器就可以实现用更短的测试时间来获得高质量的数据。通过一种快速qPCR分析方法,研究者们无需大量投资就可以提高实验通量。这种方法采用了一种高速qPCR高效混合器,从而减少了变性时间并将退火/延伸时间结合起来。该方法在保证数据质量的同时提高了分析通量。     

Recruiting and hiring women in STEM fields.

The number of women earning advanced degrees in science, technology, engineering, and mathematics (STEM) has increased, yet women remain underrepresented at all ranks of the academic hierarchy in these fields. To help explain this pattern, we explored mechanisms in the recruitment and hiring process at the level of the department that hinder or promote the hiring of women into tenure-track positions. Using a unique data set of the entire pool of applicants to tenure-track STEM faculty positions over a 6-year period at a large public research university, we identified strategies that universities and academic departments can use to increase women's representation in tenure-track positions, including placing greater emphasis on increasing the number of women applicants and placing advertisements in venues that specifically target women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Like mother, like daughter: Similarities in narrative style.

Children (2-5-year-olds and 8-13-year-olds) and their parents were independently interviewed about highly salient events: injuries serious enough to necessitate hospital emergency room treatment. Free recall narratives were scored using 14 measures of length, elaborative detail, cohesion, coherence, and provision of context. Mothers' narratives were more cohesive and coherent than fathers', and girls' narratives differed from boys' in parallel ways. Parent and child measures were correlated, and narratives of mother-daughter dyads (for the older daughters) showed striking similarity in all 5 properties, whereas there was no narrative similarity within father-son, mother-son, or father-daughter dyads. This suggests a special status for mother-daughter dyads in terms of how events come to be linguistically represented in narrative. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Room Temperature Ferrimagnetism and Ferroelectricity in Strained,Thin Films of BiFe0.5Mn0.5O3

Highly strained films of BiFe_0.5Mn_0.5O₃ (BFMO) grown at very low rates by pulsed laser deposition were demonstrated to exhibit both ferrimagnetism and ferroelectricity at room temperature and above. Magnetisation measurements demonstrated ferrimagnetism (T_C ～ 600K), with a room temperature saturation moment (M_S) of up to 90 emu/cc (～ 0.58 μ_B/f.u) on high quality (001) SrTiO₃. X‐ray magnetic circular dichroism showed that the ferrimagnetism arose from antiferromagnetically coupled Fe³⁺ and Mn³⁺. While scanning transmission electron microscope studies showed there was no long range ordering of Fe and Mn, the magnetic properties were found to be strongly dependent on the strain state in the films. The magnetism is explained to arise from one of three possible mechanisms with Bi polarization playing a key role. A signature of room temperature ferroelectricity in the films was measured by piezoresponse force microscopy and was confirmed using angular dark field scanning transmission electron microscopy. The demonstration of strain induced, high temperature multiferroism is a promising development for future spintronic and memory applications at room temperature and above.