Studies on the determination of sulfur as barium sulfate

1. The conditions affecting the accuracy of sulfur determination by barium chloride precipitation have been studied, using potassium and sodium sulfates. 2. The effect of sodium, calcium and magnesium salts has been investigated, under conditions approximating those of insecticide analysis. 3. A definite set of conditions is quoted, which if strictly observed, will yield fairly accurate analyses. For more accurate work, a method of checking by analysis of a synthetic solution is advocated. 4. The theory of the contamination of barium sulfate by extraneous substances is discussed, and the experimental data throw further light upon the nature of the adhesion phenomena. 5. An exhaustive bibliography of previous work is appended, together with abstracts of the papers

The Effect of Calcium and Protein Fed Pregnant Swine upon the Size, Vigor, Bone, Coat and Condition of the Offspring

To determine the effect of adding calcium and protein to a corn ration fed the pregnant gilt upon the relative size and vigor of the offspring, a series of experiments has been conducted at this station. The results obtained during the year 1912-13 will be discussed briefly in the following pages

What are we downloading for our children? Best-selling children’s apps in four European countries

The present article provides an overview of the best-selling apps for the age range of 0–8 years under various categories, including ‘Kids’, ‘Books’, ‘Educational games’, ‘Family games’ and ‘Word games’ in the two major application stores (Google Play and iTunes App Store) in four economically diverse European countries: Hungary, Turkey, Greece and the Netherlands. As tablets seem to be a substantial part of children’s leisure activities, and thus apps might play an important role in their development, we conducted a content analysis to highlight two issues: the educational value of the most popular children’s apps and the fine-tuning of apps to the local culture and language of non-English speaking countries. There is a large overlap between the best-selling apps in the four countries; in fact, half of the apps appear among the most popular lists in more than one country. Consequently, most children’s apps do not include any oral language and, if they do, they are not available in the local language. Furthermore, the results show that a substantial part of the apps supported early literacy skills. In the majority of apps teaching literacy, although advertised for the youngest, the focus of instruction was more suited for school-age children

Evidence for Long-Term Impact of Pasos Adelante: Using a Community-Wide Survey to Evaluate Chronic Disease Risk Modification in Prior Program Participants

Effective community-level chronic disease prevention is critical to population health within developed and developing nations. Pasos Adelante is a preventive intervention that aims to reduce chronic disease risk with evidence of effectiveness in US-Mexico residing, Mexican origin, participants. This intervention and related ones also implemented with community health workers have been shown to improve clinical, behavioral and quality of life indicators; though most evidence is from shorter-term evaluations and/or lack comparison groups. The current study examines the impact of this program using secondary data collected in the community 3–6 years after all participants completed the program. A proportional household survey (N = 708) was used that included 48 respondents who indicated they had participated in Pasos. Using propensity score matching to account for differences in program participants versus other community residents (the program targeted those with diabetes and associated risk factors), 148 natural controls were identified for 37 matched Pasos participants. Testing a range of behavioral and clinical indicators of chronic disease risk, logistic regression models accounting for selection bias showed two significant findings; Pasos participants were more physically active and drank less whole milk. These findings add to the evidence of the effectiveness of Pasos Adalente and related interventions in reducing chronic disease risk in Mexican-origin populations, and illustrate the use of innovative techniques for using secondary, community-level data to complement prior evaluation research

Renormalized kinetic theory of classical fluids in and out of equilibrium

We present a theory for the construction of renormalized kinetic equations to describe the dynamics of classical systems of particles in or out of equilibrium. A closed, self-consistent set of evolution equations is derived for the single-particle phase-space distribution function $f$, the correlation function $C=$, the retarded and advanced density response functions $\chi^{R,A}=\delta f/\delta\phi$ to an external potential $\phi$, and the associated memory functions $\Sigma^{R,A,C}$. The basis of the theory is an effective action functional $\Omega$ of external potentials $\phi$ that contains all information about the dynamical properties of the system. In particular, its functional derivatives generate successively the single-particle phase-space density $f$ and all the correlation and density response functions, which are coupled through an infinite hierarchy of evolution equations. Traditional renormalization techniques are then used to perform the closure of the hierarchy through memory functions. The latter satisfy functional equations that can be used to devise systematic approximations. The present formulation can be equally regarded as (i) a generalization to dynamical problems of the density functional theory of fluids in equilibrium and (ii) as the classical mechanical counterpart of the theory of non-equilibrium Green's functions in quantum field theory. It unifies and encompasses previous results for classical Hamiltonian systems with any initial conditions. For equilibrium states, the theory reduces to the equilibrium memory function approach. For non-equilibrium fluids, popular closures (e.g. Landau, Boltzmann, Lenard-Balescu) are simply recovered and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.Comment: 63 pages, 10 figure

Deficiency in origin licensing proteins impairs cilia formation: implications for the aetiology of meier-gorlin syndrome

Mutations in ORC1, ORC4, ORC6, CDT1, and CDC6, which encode proteins required for DNA replication origin licensing, cause Meier-Gorlin syndrome (MGS), a disorder conferring microcephaly, primordial dwarfism, underdeveloped ears, and skeletal abnormalities. Mutations in ATR, which also functions during replication, can cause Seckel syndrome, a clinically related disorder. These findings suggest that impaired DNA replication could underlie the developmental defects characteristic of these disorders. Here, we show that although origin licensing capacity is impaired in all patient cells with mutations in origin licensing component proteins, this does not correlate with the rate of progression through S phase. Thus, the replicative capacity in MGS patient cells does not correlate with clinical manifestation. However, ORC1-deficient cells from MGS patients and siRNA-mediated depletion of origin licensing proteins also have impaired centrosome and centriole copy number. As a novel and unexpected finding, we show that they also display a striking defect in the rate of formation of primary cilia. We demonstrate that this impacts sonic hedgehog signalling in ORC1-deficient primary fibroblasts. Additionally, reduced growth factor-dependent signaling via primary cilia affects the kinetics of cell cycle progression following cell cycle exit and re-entry, highlighting an unexpected mechanism whereby origin licensing components can influence cell cycle progression. Finally, using a cell-based model, we show that defects in cilia function impair chondroinduction. Our findings raise the possibility that a reduced efficiency in forming cilia could contribute to the clinical features of MGS, particularly the bone development abnormalities, and could provide a new dimension for considering developmental impacts of licensing deficiency

Post-transcriptional homeostasis and regulation of MCM2–7 in mammalian cells

The MiniChromosome Maintenance 2-7 (MCM2-7) complex provides essential replicative helicase function. Insufficient MCMs impair the cell cycle and cause genomic instability (GIN), leading to cancer and developmental defects in mice. Remarkably, depletion or mutation of one Mcm can decrease all Mcm levels. Here, we use mice and cells bearing a GIN-causing hypomophic allele of Mcm4 (Chaos3), in conjunction with disruption alleles of other Mcms, to reveal two new mechanisms that regulate MCM protein levels and pre-RC formation. First, the Mcm4Chaos3 allele, which disrupts MCM4:MCM6 interaction, triggers a Dicer1 and Drosha-dependent ∼40% reduction in Mcm2–7 mRNAs. The decreases in Mcm mRNAs coincide with up-regulation of the miR-34 family of microRNAs, which is known to be Trp53-regulated and target Mcms. Second, MCM3 acts as a negative regulator of the MCM2–7 helicase in vivo by complexing with MCM5 in a manner dependent upon a nuclear-export signal-like domain, blocking the recruitment of MCMs onto chromatin. Therefore, the stoichiometry of MCM components and their localization is controlled post-transcriptionally at both the mRNA and protein levels. Alterations to these pathways cause significant defects in cell growth reflected by disease phenotypes in mice

The Digitization of Word-of-mouth: Promise and Challenges of Online Feedback Mechanisms

Online feedback mechanisms harness the bi-directional communication capabilities of the Internet in order to engineer large-scale word-of-mouth networks. Best known so far as a technology for building trust and fostering cooperation in online marketplaces, such as eBay, these mechanisms are poised to have a much wider impact on organizations. Their growing popularity has potentially important implications for a wide range of management activities, such as brand building, customer acquisition and retention, product development, and quality assurance. This paper surveys our progress in understanding the new possibilities and challenges that these mechanisms represent. It discusses some important dimensions in which Internet-based feedback mechanisms differ from traditional word-of-mouth networks and surveys the most important issues related to their design, evaluation, and use. It provides an overview of relevant work in game theory and economics on the topic of reputation. It discusses how this body of work is being extended and combined with insights from computer science, management science, sociology, and psychology in order to take into consideration the special properties of online environments. Finally, it identifies opportunities that this new area presents for OR/MS resea

Migration, Agribusiness and Nutritional Status of Children under Five in Northwest Mexico

The aim of this study was to examine the nutritional status of children of Mexican migrant worker families under five years of age within the context of global food markets. The sample included 404 children less than five years old from farms and agricultural communities in northwest Mexico. Prevalence of stunting and underweight of children appeared very similar to that of indigenous children from the national sample survey (difference 0.9 and 1.6 percentage points, respectively). Compared to the national sample of Mexican children, stunting and underweight seemed higher in migrant children (difference 17.7 and 4.5 percentage points, respectively), but wasting, an indicator of both chronic and acute undernutrition, appeared to indicate a process of nutritional recuperation. Migrant children living in poverty and suffering from chronic undernutrition, poor performance and scarce education opportunities, can be expected to eventually become agricultural workers with low productivity and poor general health. Consumer’s demands on social and environmental standards of fresh food production in developed countries could be an opportunity to impact the lives of migrant agricultural workers, their families and communities