The production, consumption, and function of stone tools in prehispanic Central Mexico: a comparative study of households spanning the formative to postclassic period

This study evaluates how prehispanic central Mexicans made stone tools—primarily from obsidian—and used them in their homes over a period of 3,000 years. Mesoamerican scholars have often assumed the functional purposes of different lithic tools based on their material or technological attributes. Most limit their studies to single sites and extrapolate broader reconstructions of economic activities. I assess stone tool functions and associated economic activities through technological analyses of more than 43,000 lithic artifacts and, in addition, a feasibility study for high magnification use-wear analysis utilizing 589 of these artifacts from multiple household contexts in the central Mexican villages of Amomoloc (900-650 B.C.), Tetel (750-500 B.C.), and Mesitas (600-500 B.C.); the town of La Laguna (600 B.C.-A.D. 150); the city of Teotihuacan (A.D. 200-550); and the Aztec village of Cihuatecpan (A.D. 1150-1550). I determine that pressure blades—the most common tool form—were multifunctional. They were regularly modified via pressure trimming or notching and recycled through bipolar percussion to suit specific tasks. Blade production error rates decreased consistently, especially after the invention of core platform grinding near the end of the Classic period (A.D. 100-600). Preliminary results of the use-wear feasibility study suggest that certain tools became associated with specific tasks. Scrapers were mainly used to produce goods of maguey, wood, and hide. People came to use hafted atlatl dart points and bifacial knives almost exclusively for hunting and meat butchering tasks, respectively, and smaller bifacial drills mostly for shell craft production. Bipolar tools created through anvil percussion were more common during the Formative period (1500 B.C.-A.D. 100), when they were probably used as expedient kitchen utensils. Obsidian tools in central Mexico were not exclusively staple goods. Ritual bloodletting implements are spatially associated with communal altars and commoner and elite residences, but after the Epiclassic period (A.D. 600-900) bloodletting was restricted primarily to temples. Likewise, although weaponry was common during the Classic through Postclassic periods, and jewelry was relatively common during the Late Postclassic period (A.D. 1325-1521), in prehispanic times their spatial distributions were much more restricted across site contexts compared to obsidian staple goods. I demonstrate that in prehispanic central Mexico stone tools were produced and used primarily in household spaces, contrary to models that have emphasized sponsorship by elites or religious institutions. Residents produced stone tools in their homes primarily to satisfy their own needs during the Formative period. As rising populations contributed to urban densities and the development of marketplace economies, household lithic production increased to satisfy broader consumer demand. Producing households often specialized in blade production or followed a multicrafting strategy, in which the scale of production exceeded their own needs

Prader Willi syndrome: systematic review of the prevalence and nature of presentation of unipolar depression

Purpose – The purpose of this paper is to assess the prevalence and nature of presentation of unipolar depression in individuals with Prader-Willi syndrome (PWS). Design/methodology/approach – The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (2009) checklist for systematic reviews was followed where possible. Findings – Seven studies were included in the qualitative synthesis from a total of 261 records identified. The quality of the studies was then assessed: scores for each study design ranged from between 3 and 6 of a possible score total of 6. The frequency of depression ranged between studies from 4 to 22 per cent. four studies showed over 50 per cent of patients appeared to suffer from psychotic symptoms. Low mood, anhedonia and irritability were described as features of depression, although no fixed pattern of psychopathology arose from across the studies (excluding psychosis). This review has provided evidence to suggest that depression is a frequent occurrence in the PWS population. One study found that the incidence of depression differed between the genetic subtypes, raising questions regarding the relationship between genotype and behavioural phenotypes. A high proportion of individuals with depression suffered from psychotic symptoms. Research limitations/implications – The small number of heterogeneous studies included in this study precluded meta-analysis of the results. This highlights the need for further original research in this field. Practical implications – An increased awareness of the frequency of depressive symptoms within the PWS population will aid in the timely diagnosis and management of the disorder which will reduce psychiatric morbidity. The noted high proportion of psychotic symptoms associated with depression should raise the index of suspicion with clinicians and aid appropriate management decisions. Originality/value – This review has provided preliminary evidence for the nature of presentation of unipolar depression in PWS. It has highlighted the possibility of an increased propensity towards depression with psychotic symptoms. There is some suggestion of a differing presentation and course of unipolar depression between the common genetic subtypes of PWS which warrants further investigation

In vitro binding of single-stranded RNA by human Dicer

AbstractWhile Dicer alone has been shown to form stable complexes with double-stranded RNAs and short interfering RNAs, its interactions with single-stranded RNAs (ssRNAs) have not been characterized. Here, we show that recombinant human Dicer alone can bind 21-nt ssRNAs in vitro, independent of their sequence and structure. We also demonstrate that Dicer binds ssRNAs having a 5′-phosphate with greater affinity versus those with a 5′-hydroxyl. In addition, 3′-biotinylated ssRNAs are bound by Dicer with lower affinity than 3′-hydroxyl ssRNAs. The stability of ssRNA–Dicer complexes was found to depend on divalent cations. Together, our results suggest a role for the PAZ domain of Dicer in binding ssRNAs and may indicate roles for Dicer in cellular function beyond those currently known

The Spacecraft Challenge: A Student Satellite Program Accelerator

Brigham Young University’s first smallsat project, like many university smallsat projects, faced significant personnel challenges. The time required for inexperienced undergraduates to become contributing team members, combined with moderate turnover, caused overruns in the budget and schedule. To find and train future team members for employment, the student team formed a club and instituted a peer-mentored, introductory-level challenge to design, build, and fly a miniature, fully-functional model spacecraft, in one semester. At very low cost, two annual rounds of the challenge provided more than 30 students with full-cycle, design-to-flight engineering experience. Leveraging this introductory experience, many participants have now contributed to more advanced smallsat projects. We describe the low-cost project and implementation of the challenge format along with recommendations for starting similar programs at other schools

Inhibition of productive/competitive endocytic pathways enhances siRNA delivery and cell specific targeting

While the use of short interfering RNAs (siRNAs) for laboratory studies is now common practice, development of siRNAs for therapeutic applications has slowed, due in part to a still limited understanding of the endocytosis and intracellular trafficking of siRNA-containing complexes. As a result, it is difficult to design delivery vehicles for specific cell types, resulting in inefficient delivery, cytotoxicity, or immunogenicity when used in vivo. Our aim is to identify which endocytosis and intracellular trafficking pathways lead to active silencing by siRNA-containing complexes. Our work explores the preferential mechanism of endocytosis (whether by clathrin, caveolin, Arf6, Graf1, flotillin, or macropinocytosis) across multiple cell types (HeLa (cervical), H1299 (lung), HEK293 (kidney), and HepG2 (liver)). Using Lipofectamine 2000 (LF2K), fluorescentlylabeled siRNAs were delivered to cells stably expressing green fluorescent protein (GFP). Chemical inhibitors (Filipin, Dynasore, Cytochalasin D, Chlorpromazine, Amiloride, and Methyl-β- cyclodextrin) were used to identify the specific endocytic pathway internalizing the complexes. By measuring the effect of inhibitors on both intracellular levels of siRNA and GFP silencing, we were able to categorize pathways as being productive/competitive according to their functional role in facilitating gene silencing. In productive pathways, siRNAs are actively delivered to a cell and silence a target protein, whereas in competitive pathways, siRNAs are endocytosed but do not lead to silencing. Please click Additional Files below to see the full abstract

Thermodynamics and kinetics of antisense oligonucleotide hybridization to a structured mRNA target

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2002.Includes bibliographical references (p. 165-178).Antisense oligonucleotides have the potential to selectively inhibit the expression of any gene with a known sequence. Antisense-based therapies are under development for the treatment of infectious diseases as well as complex genetic disorders. Although there have been some remarkable successes, realizing this potential is proving difficult because of problems with oligonucleotide stability, specificity, affinity, and delivery. Each of these limitations has been addressed experimentally through the use of chemically-modified oligonucleotides and oligonucleotide conjugates, with much success in enhancing oligonucleotide efficacy. These early studies have shown that selection of target site, once considered a trivial problem, is critical to the success of antisense strategies. It has become clear that the efficacy of antisense oligonucleotides is a strong function of the structure of the target mRNA. Though single-stranded, RNA molecules are typically folded into complex three-dimensional structures, formed primarily by intramolecular Watson-Crick base-pairing. If an oligonucleotide is complementary to a sequence embedded in the three dimensional structure, the oligonucleotide may not be able to bind to its target site and exert its therapeutic effect. Because the majority of the structure of RNA molecules is due to Watson-Crick base-pairing, relatively accurate predictions of these folding interactions can be made from algorithms that locate the structure with the most favorable free energy of folding.(cont.) Taking advantage of the predictability of RNA structures, this thesis addresses the problem of antisense target site selection, first from a theoretical and subsequently an experimental standpoint. A thermodynamic model to predict the binding affinity of oligonucleotides for their target mRNA is described and validated using multiple in vitro and cell-culture based experimental data sets. Subsequently, direct experimental comparisons with theoretical predictions are made on the well-characterized rabbit-[beta]-globin (RBG) mRNA, using a novel, centrifugal, binding affinity assay. The importance of the hybridization kinetics is also explored, as is the role of association kinetics in defining the rate of cleavage by the enzyme ribonuclease H (RNase H). Finally, the applicability of the model in identifying biologically active oligonucleotides is demonstrated.by S. Patrick Walton.Sc.D

Indigenous University Student Persistence: : Supports, Obstacles, and Recommendations

The tumultuous history of Indigenous education in Canada has negatively affected the persistence of Indigenous peoples at university. The research goals of this study were to identify the key supports and obstacles related to Indigenous university student persistence and to make recommendations as to how to improve levels of persistence. Combining interview, survey, and database information with 527 Indigenous students revealed that the strongest factors related to persistence were (a) social engagement, including good relationships with faculty and students, and support services provided by the Indigenous gathering place for Indigenous students on campus; (b) cognitive, such as academic support at university, learning effectively on their own, and hands-on teaching; (c) physical, including insufficient financial support and availability of affordable housing and child care; and (d) cultural, including connections with Indigenous faculty and culture. Age, home location, and parental education were not found to be related to persistence. Keywords: Indigenous, Aboriginal, persistence, university, graduation, Indigenous student experience, CanadaL’histoire tumultueuse de l’éducation des Autochtones au Canada a eu un impact négatif sur la persistance des populations autochtones à l’université. Cette recherche avait pour but d’identifier les principaux soutiens et obstacles liés à la persévérance des étudiants autochtones à l’université et de formuler des recommandations. Des entretiens, des enquêtes et des bases de données convergentes de 527 étudiants autochtones révèlent que les facteurs les plus importants liés à la persévérance sont : a) sociaux – notamment les bonnes relations avec le corps enseignant et les étudiants ainsi que les services fournis par le lieu de rassemblement des Autochtones sur le campus ; b) cognitifs – comme le soutien scolaire à l’université, l’apprentissage efficace personnel et l’enseignement pratique ; c) physiques – dont l’insuffisance de soutien financier, de logement abordable et de services de garde d’enfants ; et d) culturels – principalement en lien avec le nombre d’enseignants autochtones et la culture. L’âge, le lieu de résidence et le niveau d’éducation des parents ne semblent pas associés à la persistance. Mots-clés : autochtones, premières nations, persistance, université, diplomation, expérience des étudiants autochtones, Canad

Modulation of selenium tissue distribution and selenoproteins expression in Atlantic salmon (Salmo salar L.) fed diets with graded levels of plant ingredients

Increased substitution of marine ingredients by terrestrial plant products in aquafeeds has proved to be suitable for Atlantic salmon farming. However, a reduction in omega-3 long-chain polyunsaturated fatty acids is a consequence of this substitution. In contrast, relatively little attention has been paid to the effects of fish meal and oil substitution on levels of micronutrients such as selenium (Se), considering fish are major sources of this mineral for human consumers. To evaluate the effects of dietary marine ingredient substitution on tissue Se distribution and the expression of Se metabolism and antioxidant enzymes genes, Atlantic salmon were fed three feeds based on commercial formulations with increasing levels of plant proteins (PP) and vegetable oil. Lipid content did not vary at any sampling point in flesh, whereas was higher in fish fed higher PP in liver of 1 kg fish. Fatty acid content reflected dietary input and was related to oxidation levels. Liver had the highest Se levels, followed by head kidney whereas the lowest contents were found in brain and gill. The Se concentration of flesh decreased considerably with high levels of substitution, reducing the added value of fish consumption. Only brain showed significant differences in glutathione peroxidase, tRNA selenocysteine associated protein 1 and superoxide dismutase expression, whereas no significant regulation of Se related genes was found in liver. Although Se levels in the diets satisfied essential requirements of salmon, high PP levels led to a reduction in the supply of this essential micronutrient