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This fully revised fifth edition provides comprehensive coverage of flexible multibody system dynamics. Including an entirely new chapter on the integration of geometry, durability analysis, and design, it offers clear explanations of spatial kinematics, rigid body dynamics, and flexible body dynamics, and uniquely covers the basic formulations used by the industry for analysis, design, and performance evaluation. Included are methods for formulating dynamic equations, the floating frame of reference formulation used in small deformation analysis, and the absolute nodal coordinate formulation used in large deformation analysis, as well as coverage of industry durability investigations. Illustrated with a wealth of examples and practical applications throughout, it is the ideal text for single-semester graduate courses on multibody dynamics taken in departments of aerospace and mechanical engineering, and for researchers and practicing engineers working on a wide variety of flexible multibody systems.
Can foreign capital empower dictatorship? This groundbreaking book develops a unified theory that links three prominent forms of international capital to the endurance of dictatorships. International capital empowers governments to finance two key instruments of non-democratic politics: repression and patronage. The Perils of International Capital uses theory, case studies, and cross-national statistical evidence to demonstrate causal effects between foreign capital and authoritarian politics. These finding are crucial to scholars and policymakers alike, as they call for a recalibration of the welfare effects associated with greater financial globalization. Ahmed reveals that, while foreign capital may improve economic development, it can tragically hinder democratic governance in the process.
Wake-up stroke (WUS) or ischemic stroke occurring during sleep accounts for 14%–29.6% of all ischemic strokes. Management of WUS is complicated by its narrow therapeutic time window and attributable risk factors, which can affect the safety and efficacy of administering intravenous (IV) tissue plasminogen activator (t-PA). This manuscript will review risk factors of WUS, with a focus on obstructive sleep apnea, potential mechanisms of WUS, and evaluate studies assessing safety and efficacy of IV t-PA treatment in WUS patients guided by neuroimaging to estimate time of symptom onset. The authors used PubMed (1966 to March 2018) to search for the term “Wake-Up Stroke” cross-referenced with “pathophysiology,” ‘‘pathogenesis,” “pathology,” “magnetic resonance imaging,” “obstructive sleep apnea,” or “treatment.” English language Papers were reviewed. Also reviewed were pertinent papers from the reference list of the above-matched manuscripts. Studies that focused only on acute Strokes with known-onset of symptoms were not reviewed. Literature showed several potential risk factors associated with increased risk of WUS. Although the onset of WUS is unknown, a few studies investigated the potential benefit of magnetic resonance imaging (MRI) in estimating the age of onset which encouraged conducting clinical trials assessing the efficacy of MRI-guided thrombolytic therapy in WUS.
Aquaculture is one of the fastest-growing food production sectors in many low-income and food-deficit countries with aquatic ecozones. Yet its specific impact on nutrition and livelihood in local communities, where commercial and/or export-orientated aquaculture activities are developed, is largely unknown.
The present narrative and argumentative review aims to provide an overview of our current understanding of the connections between aquaculture agroecosystems, local and national fish production, fish consumption patterns and nutrition and health outcomes.
The agroecological dynamic in a coastal-estuarine zone, where the aquatic environment ranges from fully saline to freshwater, is complex, with seasonal and annual fluctuations in freshwater supply creating a variable salinity gradient which impacts on aquatic food production and on food production more generally. The local communities living in these dynamic aquatic ecozones are vulnerable to poverty, poor diet and health, while these ecosystems produce highly valuable and nutritious aquatic foods. Policies addressing the specific challenges of risk management of these communities are limited by the sectoral separation of aquatic food production – the fisheries and aquaculture sector, the broader food sector – and public health institutions.
Here we provide an argument for the integration of these factors to improve aquaculture value chains to better address the nutritional challenges in Bangladesh.
This article intends to review William Dembski's recent monograph entitled Being as Communion: A Metaphysics of Information, in which he establishes an entire information-centric metaphysics. This viewpoint is compared with al-Ghazālī’s perspective, a Muslim philosophical theologian from the Medieval period. It is concluded that what Dembski defines as information, which for him is the ontological basis of the natural world, seems remarkably close to al-Ghazālī’s notion of God's will and omnipotence. This article is an explorative comparison of their metaphysical frameworks that are discussed in light of modern scientific developments, highlighting their differences and similarities.
In this paper, a multi-objective design optimization of the 3-UPU translational parallel manipulator is presented. Based on a new algorithm, which combines the genetic algorithms and the Krawczyk operator, the robot position error is minimized and the robot design parameters tolerances are maximized, simultaneously. The results show that the designer can maintain the manipulator accuracy by using a specific size of the base, and can restrict its tolerance even by enlarging the actuators’ tolerance intervals. This algorithm is also used to determine the maximum design parameters tolerances for an allowable robot position error. The proposed algorithm can be extended to optimize other types of robots.
Despite the improvements seen in efficiency of GaAs cells over the years, there remains room for improvement for it to approach the theoretical single junction limit posited by Shockley and Quiesser decades ago. One of the more pursued options is the growth of quantum wells within the structure of GaAs to enhance its photon absorption below its bandgap. Multiple Quantum Wells (MQW) have been an ongoing topic of research and discussion for the scientific community with structures like InGaAs/GaAs and InGaP/GaAs quantum wells producing promising results that could potentially improve overall energy conversion. Here, we used WEIN2K, a commercial density functional theory package, to study the ternary compound Ga1-xTlxAs and determine its electronic properties. Using these results combined with experimental confirmation we extend these properties to simulate its application to form a MQW GaAs/ Ga1-xTlxAs solar cell. Ga1-xTlxAs is a tunable ternary compound, with its bandgap being strongly dependent on the concentration of Tl present. Concentrations of Tl as low as 7% can reduce the bandgap of Ga1-xTlxAs to roughly 1.30 eV from GaAs’s 1.45 eV at room temperature with as little as a 1.7% increase in lattice constant. The change in bandgap, accompanied by the relatively small change in lattice constant makes Ga1-xTlxAs a strong candidate for a MQW cell with little to no strain balancing required within the structure to minimize unwanted defects that impede charge collection within the device. Our GaAs photodiode with TlGaAs MQWs shows an expanded absorption band and improved conversion efficiency over the standard GaAs photovoltaic cell with dilute concentrations of Tl incorporated into the compound.
be an odd prime number and
an elliptic curve defined over a number field
with good reduction at every prime of
. We compute the Euler characteristics of the signed Selmer groups of
over the cyclotomic
-extension. The novelty of our result is that we allow the elliptic curve to have mixed reduction types for primes above
and mixed signs in the definition of the signed Selmer groups.
The present study investigated the risks and benefits of routine Fe–folic acid (IFA) supplementation in pregnant women living in low- and high-groundwater-Fe areas in Bangladesh.
A case-controlled prospective longitudinal study design was used to compare the effect of daily Fe (60 mg) and folic acid (400 μg) supplementation for 3·5 months.
A rural community in Bangladesh.
Pregnant women living in low-groundwater-Fe areas (n 260) and high-groundwater-Fe areas (n 262).
Mean Hb and serum ferritin concentrations at baseline were significantly higher in pregnant women in the high-groundwater-Fe areas. After supplementation, the mean change in Hb concentration in the women in the low-groundwater-Fe areas (0·10 mg/dl) was higher than that in the pregnant women in the high-groundwater-Fe areas (–0·08 mg/dl; P = 0·052). No significant changes in the prevalence of anaemia or Fe deficiency (ID) in either group were observed after IFA supplementation; however, the prevalence of Fe-deficiency anaemia (IDA) decreased significantly in the women in the low-groundwater-Fe areas. The risk of anaemia, ID and IDA after supplementation did not differ significantly between the groups. None of the participants had Fe overload. However, a significant proportion of the women in the high- and low-groundwater-Fe areas remained anaemic and Fe-deficient after supplementation.
IFA supplementation significantly increased the Hb concentration in pregnant women living in the low-groundwater-Fe areas. Routine supplementation with 60 mg Fe and 400 μg folic acid does not pose any significant risk of haemoconcentration or Fe overload. Further research to identify other nutritional and non-nutritional contributors to anaemia is warranted to prevent and treat anaemia.
Waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer] and Palmer amaranth (Amaranthus palmeri S. Watson) are troublesome weeds of row-crop production in the United States. Their dioecious reproductive systems ensure outcrossing, facilitating rapid evolution and distribution of resistances to multiple herbicides. Little is known, however, about the genetic basis of dioecy in Amaranthus species. In this work, we use restriction site–associated DNA sequencing (RAD-Seq) to investigate the genetic basis of sex determination in A. tuberculatus and A. palmeri. For each species, approximately 200 plants of each sex were sampled and used to create RAD-Seq libraries. The resulting libraries were separately bar-coded and then pooled for sequencing with the Illumina platform, yielding millions of 64-bp reads. These reads were analyzed to identify sex-specific and sex-biased sequences. We identified 345 male-specific sequences from the A. palmeri data set and 2,754 male-specific sequences in A. tuberculatus. An unexpected 723 female-specific sequences were identified in a subset of the A. tuberculatus females; subsequent research, however, indicated female specificity of these markers was limited to the population from which they were identified. Primer sets designed to specifically amplify male-specific sequences were tested for accuracy on multiple, geographically distinct populations of A. tuberculatus and A. palmeri, as well as other Amaranthus species. Two primer sets for A. palmeri and four primer sets for A. tuberculatus were each able to distinguish between male and female plants with at least 95% accuracy. In the near term, sex-specific markers will be useful to the A. tuberculatus and A. palmeri research communities (e.g., to predict sex for crossing experiments). In the long-term, this research will provide the foundational tools for detailed investigations into the molecular biology and evolution of dioecy in weedy Amaranthus species.
Irrational prescription of drugs in children is reported to be widespread. There are scarce studies on the pediatric prescribing pattern especially at primary health care (PHC) level.
To determine the physicians’ prescribing patterns for children under five years, to explore completeness of prescriptions’ recorded information, and to analyze the core indicators of drug prescribing at primary health care centers (PHCC) in Qassim.
This cross-sectional study was conducted on 25 randomly selected PHCCs. All prescriptions, for the first week of first six months of the year 1437 Hijrah (October 2015 to April 2016), were reviewed. Among 25 012 prescriptions, 4125 (16.5%) were for children under five years. We randomly selected 1212 prescriptions for the study. World Health Organization (WHO) specified drug use indicators, and index of rational drug prescribing (IRDP) with a maximum value of 5, were calculated. The physicians and pharmacists of sampled PHCCs were also surveyed to explore prescribing issues.
The completeness of recorded date, patient age, and gender was more than 90%. The diagnosis was legibly written in 842 (69.5%), while the patient weight was recorded in 307 (25.3%) prescriptions. The least commonly recorded instruction was the drug strength (26.8%), while the dose and frequency of use were stated for 91.3% and 90.8% of the drugs, respectively. The average number of drugs per prescription was 2.35 ± 0.89; 72.97% drugs were prescribed by generic name; in 65.98% patient encounters, antibiotics were prescribed. The overall IRDP was 3.56. Most of the physicians and pharmacists reported availability of the drug list and Saudi PHC formulary in their PHCCs.
PHC physicians’ drug prescribing was not at the optimal level of rational use, especially regarding prescription of antibiotics. Creating awareness about rational drug use and hazards of overuse of antibiotics is needed.
Using general-purpose photovoltaic device model, we have simulated the operation and functionality of a working Sn perovskite/Cu2O hole transport layer (HTL)/Cu back-contact device versus a standard Pb perovskite/Spiro HTL/Ag back-contact device. The results are extremely promising in that they showcase comparable cell efficiencies, with the Sn perovskite/Cu2O HTL/Cu back-contact device showing a highest 22.9% efficiency [Jsc of 353.4 A/m2, Voc of 0.84 V, fill factor (FF) of 0.77] at 427 nm active layer thickness compared with 24.6% of the standard Pb perovskite/Spiro HTL/Ag back-contact device (Jsc of 356.8 A/m2, Voc of 0.82 V, FF of 0.84) at the same active layer thickness. Jsc, Voc, and FF kinetics reveal that the Sn perovskite/Cu2O HTL/Cu back-contact device can perform better by reducing the recombination centers both within each layer matrix and in the interfacial contacts.
A 5G new radio cellular system is characterized by three main usage scenarios of enhanced mobile broadband (eMBB), ultra-reliable and low latency communications (URLLC), and massive machine type communications, which require improved throughput, latency, and reliability compared with a 4G system. This overview paper discusses key characteristics of 5G channel coding schemes which are mainly designed for the eMBB scenario as well as for partial support of the URLLC scenario focusing on low latency. Two capacity-achieving channel coding schemes of low-density parity-check (LDPC) codes and polar codes have been adopted for 5G where the former is for user data and the latter is for control information. As a coding scheme for data, 5G LDPC codes are designed to support high throughput, a variable code rate and length and hybrid automatic repeat request in addition to good error correcting capability. 5G polar codes, as a coding scheme for control, are designed to perform well with short block length while addressing a latency issue of successive cancellation decoding.