Universal Generator of Ultra-Wideband Pulses

An Ultra-Wideband (UWB) subnanosecond pulse generator is described in this paper. High amplitude Gaussian pulses are generated by a Step Recovery Diode (SRD) included in a novel pulse forming circuit. The pro-posed circuit solution utilizes the performance of the SRD effectively, without excessive requirements regarding the driver section of the generator. Monocycle pulses are then generated by an additional pulse forming network. A sim-ple transistor driver is also described, which transforms a TTL trigger signal to a driving pulse with the timing and amplitude parameters required by the SRD. Measurement results are presented, which show the proposed generator operating with stable output pulse parameters at arbitrary pulse repetition frequency up to 20 MHz. The generated monocycle pulses are 25 V in amplitude and approximately 500 ps in width

A Double H-Shaped Resonator for an Isotropic ENG Metamaterial

This paper presents a new planar particle showing negative effective permittivity under irradiation by an electromagnetic wave. The response of this particle, aimed to be sensitive to an electric field, is strongly anisotropic. The particle is used to design an isotropic epsilon-negative metamaterial in two forms. Firstly, a unit cell of the metamaterial consists of a cube bearing six proposed particles on its faces, located with specific orientations. The experiments showed that this unit cell is suitable for manufacturing an isotropic epsilon-negative metamaterial obtained by arranging these cells in a 3D cubic periodic system. The second form of an epsilon negative metamaterial with an isotropic response consists of the proposed planar particles themselves, distributed quasi-randomly, composing a 2D system and/or of particles placed in spherical shells and distributed fully randomly in a hosting material composing a 3D system. The isotropy of these systems was verified by measurements in a rectangular waveguide

Isotropic Epsilon-Negative Particles

This paper presents two particles with negative permittivity in some frequency band. The response of a single dipole loaded by an inductance is strongly anisotropic. The response of a spider dipole does not depend on the orientation of the electric field of a wave being incident perpendicular to the particle substrate. These two particles are used in designing an isotropic epsilon-negative metamaterial. A unit cell of the metamaterial consists of a cube bearing the proposed particles on its faces, located with specific orientations. The experiments showed that only the single inductively loaded dipole is suitable for manufacturing of an isotropic epsilon-negative metamaterial. The isotropy of the new particles was checked by measurements

Isotropic Single Negative Metamaterials

This paper presents the application of simple, and therefore cheap, planar resonators for building 3D isotropic metamaterials. These resonators are: a broadside-coupled split ring resonator with a magnetic response providing negative permeability; an electric dipole terminated by a loop inductor together with a double H-shaped resonator with an electric response providing negative permittivity. Two kinds of 3D isotropic single negative metamaterials are reported. The first material consists of unit cells in the form of a cube bearing on its faces six equal planar resonators with tetrahedral symmetry. In the second material, the planar resonators boxed into spherical plastic shells and randomly distributed in a hosting material compose a real 3D volumetric metamaterial with an isotropic response. In both cases the metamaterial shows negative permittivity or permeability, according to the type of resonators that are used. The experiments prove the isotropic behavior of the cells and of the metamaterial specimens

Nitrate Contamination in Two California Groundwater Basins: What Creates Disparities?

Nitrate contamination is a major problem within California groundwater basins. A form of nitrogen, nitrates leach into groundwater aquifers from the surface where they remain for many decades. The most common source for the contaminant is agricultural sources like nitrogen fertilizer. Consequently, the problem is concentrated in regions of the state with a history of large-scale agricultural production. When water is pulled from contaminated basins and used as drinking water, the nitrates can cause serious negative health consequences, most commonly methemoglobinemia, also known as blue baby syndrome. In this thesis, I will examine what factors contribute to a region’s ability to successfully manage nitrate contamination issues. I completed a comparative analysis of two California counties, Santa Clara County and Tulare County. Both have a history of large-scale agriculture, but only one has been able to successfully manage nitrate contamination. Through an examination of their history, local government structures, well data, and demographics, this thesis seeks to identify what factors have created the disparity in nitrate levels between these two counties

Implementing Assessment literacy in ESL/EFL at Undergraduate Level in Bangladeshi Universities: Imperativeness and Challenges

The paper concentrates on investigating the implementation of assessment literacy at the tertiary level of Bangladesh. It also tries to explore the existing challenges which the teachers face in ELT classroom while implementing effective assessment techniques in evaluating academic examination scripts. In this regard, a survey method involving a questionnaire survey was used to obtain a quantitative insight of the study. After studying the responses from 10 respondents of two public universities of Bangladesh, the researcher attained the findings that demonstrated respondents’ experience and suggestions regarding assessment literacy in English language teaching at undergraduate level in the respective university, which include a number of barriers, like lack of training in achieving assessment literacy, insufficient support from the university, and disparity between learning objectives and assessment techniques. To ensure bonafide assessment literacy, the findings also provided some feasible suggestions, like offering students an opportunity to convert test into learning experiences, ensuring appropriate math between assessment and learner ability and regulating self-assessment on regular basis

THE IMPACT OF ANTIDEPRESSANT USES ON COMMUNITY-DWELLING OLDER ADULTS IN THE US

Mental health is a vital component of the overall well-being across the lifespan and is the third leading cause of disability globally. One in seven US adults aged 65 or older reported some anxiety and/or depression symptoms, but one in four older adults use some antidepressants and the prescriptions were steadily increasing. This study investigated the impact of antidepressant uses focusing on discontinuation of antidepressants and the risk of medication resumption, inconsistency of antidepressant prescription, and increased healthcare uses by self-reported anxiety and depression symptoms among community-dwelling older adults in the US. Our study conducted a longitudinal study using Medicare Current Beneficiary Survey (MCBS) data from 2015 to 2019. We included beneficiaries aged 65 years or older with information of anxiety, depression, and part D prescription drug benefits. Anxiety and depression symptoms were self-reported with Generalized Anxiety Disorder questionnaire (GAD-2) and Patient Health Questionnaire (PHQ-8). Survival analysis, logistic regression, and zero-inflated Poisson regression were used for the analysis. We identified 18,567 older adults in our cohort with at least one year follow-up. The median duration of continuous medication was 90 days. However, about 30% of patients had a treatment duration of 30 days or shorter and 30% for 181 days or more. Older adults with less than 30 days of continuous treatment were half as likely to resume the medications compared to those with 91-180 days of treatment. On the other hand, 1,837 (11.2%) of older adults reported any anxiety symptoms, 1,405 (8.6%) reported either depression or loss of interest. Older adults with at-risk anxiety received 41% and at-risk depression received 51% more antidepressant prescriptions. The overall hospitalization rate was 11% and the emergency department (ED) visit rate was 13%. Older adults reporting loss of interest had a 27% higher hospitalization rate and 29% higher risk of ED visits. Who took antidepressants for \u3e90 days had a 17% lower hospitalization rate than those with a duration of ≤ 90 days. Symptoms and treatment of anxiety and depression are varied among older adults. Healthcare providers should give careful consideration for screening and treating older adults for anxiety and depression

Exploring General Science Questions of Secondary School Certificate (SSC) Examination: Assessment Effects on Students Learning

Creative question is generally considered as a tool to measure students’ various levels of learning. The study focused on exploring the present situation of General Science test items/creative questions in Bangladesh. This descriptive study was conducted using a concurrent triangulation research design. To conduct this study both quantitative and qualitative data were collected. 16 test of General Science test items/creative question papers of 2015 or 2016 were selected purposively as sample from all educational boards. 48 students were selected conveniently for interview from those who had been passed the SSC examination of 2015 or 2016. For collecting data from these sources test analysis protocol and interview protocol were used as research tools. Test analysis protocol was consisted of two criteria; wording criteria and practicing criteria. Selected test items were analysed based on these two criteria and Bloom’s cognitive domain. The study revealed that major test items were developed in a way which direct students towards lower level learning. Few test items were focused to students understanding, application and higher order learning. In practice, students were engaged to only memorization and understanding through SSC examination assessment. Few test items were devoted to application level learning of students. Higher order learning was totally ignored in SSC examination questions. Keywords: General Science, Examination, Assessment, SSC, Students Learning, Secondary Education

EFFECT OF NITROGEN, SILICON AND ORGANIC FERTILIZER MANAGEMENT ON GROWTH, YIELD AND LODGING OF TRADITIONAL AROMATIC RICE

A Thesis Submitted to the Department of Agricultural Botany Sher-e-Bangla Agricultural University, Dhaka In partial fulfillment of the requirements for the degree of MASTER OF SCIENCE (MS) IN AGRICULTURAL BOTANY SEMESTER: JANUARY- JUNE, 2021A field experiment was carried out at Experimental Field of Department of Agricultural Botany, Sher-e-Bangla Agricultural University (SAU), Dhaka to study he effect of nitrogen, silicon and organic fertilizer management on growth, yield and odging of traditional aromatic rice. The cultivars were grown during Boro season, 2019-20 (November, 2019 to May, 2020). The experiment consisted of two factors; Factor-A: three aromatic rice varieties viz. V 1 = Badshabhog, V = Chiniatab awnless) and V = Kataribhog (awnless) and Factor B: four levels of fertilizer management viz. T 3 1 = {30(BS) +20 (MT) + 10 (BPI)} kg ha -1 + no silicon and cowdung, T 2 = {30(BS) +20 (MT) + 10 (BPI)} kg ha -1 + silicon (450 SiO ) + no cow-dung, T 3 = {30(BS) +20 (MT) + 10 (BPI)} kg ha -1 + No silicon + cow-dung (6 t ha -1 ) and T 4 = {30(BS) +20 (MT) + 10 (BPI)} kg ha -1 + silicon (450 SiO ) + cow-dung (6 t ha -1 ) (BS= basal dose; MT= mid-tillering and BPI= before panicle nitiation). The experiment was set up in two factors Randomized Complete Block Design (RCBD) with three replications. In case of varietal performance, V Badshabhog) showed highest plant height, number of tillers hill -1 2 2 kg ha 2 -1 kg ha , leaf area index, 4 nternode diameter, culm height and culm dry weight, length and fresh weight of nternodes and chlorophyll content compared to V 2 (Chiniatab) and V (Kataribhog). The highest number of filled grains panicle -1 , grain weight hill -1 , ratio of spikelet number to LA and ratio of yield sink to LA were also achieved by V (Badshabhog) and this variety showed highest grain yield (2.52 t ha -1 ) which is 3.28% and 11% higher than V 2 (Chiniatab) and V 3 3 1 (Kataribhog), respectively. Similarly, variety V Chiniatab) showed highest lodging resistance and aroma quality which was very close to the variety V 1 (Badshabhog) whereas V (Kataribhog) showed least performance. Again, in terms of fertilizer management practices, plant height, tiller number, leaf area, 4 th 3 internode diameter, culm height and dry weight, length and resh weight of internodes and chlorophyll content increased progressively with ncreasing fertilizers application and best result was achieved from T treatment compared to control treatment T 1 . The highest number of filled grains panicle , grain weight hill -1 , ratio of spikelet number to LA and ratio of yield sink to LA were also ound from T 4 treatment. This treatment (T ) also showed highest grain yield (2.76 t ha -1 4 ) with is 40.82% higher than control and 5.34% and 20% higher than T , espectively. The best performance of lodging resistance was performed by T ollowed by T but there was no significant effect of fertilizer management on aroma quality. In case of treatment combinations, V 2 1 T performed best in producing higher yield of rice (2.89 t ha -1 4 ) due to production of higher spikelets panicle , number of illed grains panicle -1 and grain weight hill -1 from V 1 T 4 whereas V showed the owest yield (1.86 t ha -1 ). Similarly, the treatment combination of V and V 2 T 4 showed strong lodging resistance and V 2 T 1 , V 2 T 2 , V 2 T 3 and V 2 T showed strong aroma quality of rice. These results suggested that fertilizer management plays a vital ole for improving stem strength in different rice cultivars. Regarding yield and odging resistance, firstly Badshabhog and next to Chiniatab and Kataribhog with SiO and cow-dung can be recommended. To obtain best aroma, Chiniatab can be ecommended with the same treatment. 2 3 -1 T 4 1 1 T 4 4 2 , V -1 -1 and T 2 T 2 1 th 2 3