Design and linearization of an efficient class E power amplifier using a test bench based on development boards

Nowadays, with the increase in small satellites applications for Earth observation, the need for high efficient transmitters capable of delivering the required power, taking into account not only the power consumption limitations of small satellites (solar powered), but also the required linearity to allow high data rates in the downlink, has fostered the research on alternatives to the classical transmitter amplification. This Master Thesis has the objective to mitigate the inherent trade-off between linearity and efficiency in communication transmitters by addressing the design of an efficient Power Amplifier (PA) combined with the implementation of Crest Factor Reduction (CFR) and Digital Predistortion (DPD) techniques. For this purpose, the deployment of a low-budget test bench based on development boards is proposed to carry out the PA evaluation and linearization avoiding the use of expensive laboratory equipment for signal generation and analysis. The experimental campaign was carried out using CFR technique to limit the Peak to Average Power Ratio (PAPR) in addition to the DPD linearization, this method not only allowed us to reduce spectral regrowth and minimize in-band distortion, but also was a crucial approach to maximize power amplifier efficiency fulfilling the linearity requirement imposed by the communications standards. The evaluation of the class-E PA designed (under the supervision of the Communication Engineering research group of the University of Cantabria) was performed using a LTE-like signal of 20 MHz employing Quadrature Amplitude Modulation (QAM) and Orthogonal Frequency-Division Multiplexing (OFDM). The measurements shown that it is possible to achieve an output power of 36,6 dBm with an efficiency about 50% in contrast to the typical class-AB PA efficiency figures ranging from 5-10% when operated with significant back-off levels to avoid saturation. Moreover, the Adjacent Channel Power Ratio (ACPR) is below -45 dB and the Error Vector Magnitude (EVM) is around 1,4% for a 64QAM signal in compliance with the communication standards

Demographics of Suicide Victims in Maine for 2017 and 2018 with Emphasis on Suicide Notes

This study examined Maine suicide deaths from 2017 and 2018 to determine if there were correlations between the demographics of suicide victims and variables of the suicide acts: age, gender, veteran status, method, and presence of a note. Results indicate that 30 percent of suicide victims in Maine a left note. Initial findings from this study revealed interesting correlations between the act of leaving a suicide note and suicide methods that require advanced planning, e.g., carbon monoxide poisoning. A lower percentage of notes were associated with spur-of-the-moment type suicides. Based on these preliminary findings, we suggest modifying targeted interventions to mitigate and reduce suicide rates in Maine including programs to support overlooked vulnerable populations. Due to Maine’s high rate of suicide by firearms, we also suggest that new policies and laws be implemented to limit access to and possession of firearms for individuals identified as at risk of suicide

Identifying Elder Abuse in the Emergency Department: Toward a Multidisciplinary Team-Based Approach

Elder abuse and neglect are defined as action or negligence against a vulnerable older adult that causes harm or risk of harm, either committed by a person in a relationship with an expectation of trust or when an older person is targeted based on age or disability. This mistreatment may include physical abuse, sexual abuse, neglect, psychological abuse, or financial exploitation; many victims experience multiple types of abuse. Elder abuse is both common and costly. It has an estimated prevalence of 5% to 10% and has been linked to major adverse health outcomes, including dementia, depression, and mortality. Although not easily quantified, elder abuse is estimated to cost many billions of dollars annually. In addition to community-dwelling older adults, residents of skilled nursing facilities may also be victims of mistreatment by staff members or other residents

Lactic Acid Bacteria from Argentinean Fermented Foods: Isolation and Characterization for their Potential Use as Starters for Fermentation of Vegetables

Bakterije mliječno-kiselog vrenja poboljšavaju organoleptička, hranjiva i fizikalno-kemijska svojstva tradicionalne hrane. U radu smo odabrali 31 fermentirani prehrambeni proizvod (na bazi mlijeka i povrća), kupljen u lokalnim dućanima u gradu Tucumán, Argentina, kao izvore bakterija mliječno-kiselog vrenja za dobivanje ukiseljenih proizvoda. Ispitana su tehnološka svojstva 64 izolata za koja se pretpostavilo da pripadaju vrsti Lactobacillus, a koji bi se mogli upotrijebiti u proizvodnji fermentirane hrane. Većina je sojeva imala dobro svojstvo zakiseljavanja (>0,04 pH jedinica po satu) i proteolitička svojstva (slobodne aminokiseline>1 mmol/L), proizvodila diacetil i/ili acetoin i bila otporna na prisutnost 4 % NaCl. Prema količini proizvedene kiseline i osmotoleranciji odabrali smo 6 bakterija i identificirali ih sekvenciranjem 16S rDNA (identičnost 97-100 %) kao: Lactobacillus rhamnosus CRL2159 i CRL2164, L. plantarum CRL2161 i CRL2162, te Weissella viridescens CRL2160 i W. paramesenteroides CRL2163. Zatim smo procijenili njihova svojstva bitna za proizvodnju ukiseljenog povrća. Pri pH-vrijednosti od 4,5 i u prisutnosti 7 % NaCl izolati L. plantarum CRL2162 i L. rhamnosus CRL2164 imali su najbolji rast i inhibicijski učinak na bakterije Escherichia coli i Listeria innocua. Nije zamijećen antagonizam između odabranih sojeva koji bi spriječio njihovu uporabu u mješovitim kulturama, dok njihova svojstva upućuju na zaključak da se mogu koristiti kao starter kulture u proizvodnji visokokvalitetnog fermentiranog povrća. Razvoj tih novih starter kultura mogao bi povećati kompetitivnost proizvoda iz Argentine i njihovu zastupljenost na tržištu konzerviranog povrća.Lactic acid bacteria (LAB) improve the organoleptic, nutritional and physicochemical properties of artisanal foods. In this study, we selected 31 fermented dairy and vegetable foods marketed in Tucumán city, Argentina, as sources of LAB for the production of pickles. Sixty-four isolates presumptively identified as Lactobacillus strains were screened for relevant technological properties for production of fermented foods. Most strains showed moderate to good acidification (>0.04 pH units/h) and proteolytic capabilities (free aminoacids >1 mmol/L), produced diacetyl and/or acetoin and were resistant to 4 % NaCl. Based on acid production and osmotolerance, we selected six LAB strains and identified them by 16S rDNA sequencing (97–100 % identity) as: Lactobacillus rhamnosus CRL2159 and CRL2164, L. plantarum CRL2161 and CRL2162, Weissella viridescens CRL2160 and W. paramesenteroides CRL2163. Relevant properties for pickle manufacturing were further assessed. At an initial pH=4.5 and 7 % NaCl, L. plantarum CRL2162 and L. rhamnosus CRL2164 performed the best with high growth and inhibitory activity against Escherichia coli and Listeria innocua. There was no obvious antagonism among the selected strains that would dismiss their use in mixed cultures. Properties of the selected LAB suggest their potential as starter cultures for obtaining standardized, fermented vegetable products of high quality. The development of these new industrial starters would increase the competitiveness of production and open the country’s frontiers in the canned vegetable market

Salicylate Poisoning Potential of Topical Pain Relief Agents: From Age Old Remedies to Engineered Smart Patches

The pain relief capabilities of methyl salicylate are well established and a multitude of over-the-counter products populate pharmacy shelves. Over-application of the topical preparation containing the drug, or its accidental ingestion, invariably result in salicylate poisoning and in severe cases can be fatal. The drug has been a regular feature of the US National Poison Database Survey over the past decade and continues to pose a risk to children and adults alike. The aim of the review has been to cast a spotlight on the drug and assess why its use remains problematic, how technology could offer more efficacious delivery regimes, and minimise the possibility of accidental or intentional misuse