62 research outputs found

    A Study of Solders

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    The purpose of this paper is to furnish a qualitative method of comparing the degree of wetting of various solders upon different plate metals when several fluxes are used

    An Experimental Study of the Effects of Modularity on Resource Consumption in Software Development

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    Many authors have encouraged the use of modular programming techniques in software development. In fact, there is almost total agreement within industrial and academic circles that modularity is a desirable feature of any software package. Unfortunately, the desirability of modular design is almost always voiced without support from experimental evidence. This paper consists of an experiment comparing the resource consumption of programmers based on the modularity practices employed during the design and programming phases of software development. The experiment tests the effectiveness of modularity in reducing psychological complexity of software. The results of the research show that in some cases there is indeed a difference in resource consumption between the modularity practices tested. However, the stated benefits of modularity did not carry over to the design and programming phases of software development. The use of modularity seemed, in fact, to increase development costs in some cases

    The Effect of Kipping on the Performance of a Pull-up

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    The high prevalence of obesity and sedentary lifestyle contribute to the growing burden of health care costs, incidence of disease, and mortality, making a lifestyle that includes regular physical activity increasingly important. Low intensity resistance training has been studied as a possible intervention to increase physical activity in inactive individuals. To determine the effects of a weighted vest treatment (WV) on steady state VO2, O2 deficit, VO2max, body mass index (BMI), and resting blood pressure (RBP). Fourteen college age women participated in a 4 week trial and completed both pre and posttest evaluations. These evaluations included a submaximal exercise bout, a maximal graded exercise test, determination of BMI, and measurement of RBP. Seven participants wore a weighted vest, fitted with 10% of their body weight, during normal daily activities for a minimum of 10 hours a day, 5 days each week. The remaining 7 participants served as a control group. ANCOVAs, with pretest measures serving as the covariates, were conducted to determine the effect of WV on posttest responses. Mean (sd) pre-test O2 deficit values were 0.64 (0.18) and 0.68 (0.18) for the control and WV groups, respectively. Mean (sd) post-test O2 deficit values were 0.62 (0.15) and 0.38 (0.17) for the control and WV groups, respectively. Results of the ANCOVA revealed a significant effect of WV on O2 deficit with O2 deficit values being lower following WV (F(1,11) = 7.30, p = 0.02). Further, WV accounted for about 40% of the change observed in posttest O2 deficit values (ηp2 = 0.40). However, no significant effect of WV was seen on steady state VO2, VO2 max, BMI, or RBP. WV resulted in lower O2 deficit values suggesting that it could elicit training effects related to improved aerobic function. Possible explanations for the lack of effects on other variables could be related to the limitations imposed by the relatively small sample size and trial length. Future studies designed with larger sample sizes and longer trial periods might prove more effective in evaluating the effect of WV on eliciting health related benefits

    Mammary stem cells have myoepithelial cell properties.

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    Contractile myoepithelial cells dominate the basal layer of the mammary epithelium and are considered to be differentiated cells. However, we observe that up to 54% of single basal cells can form colonies when seeded into adherent culture in the presence of agents that disrupt actin-myosin interactions, and on average, 65% of the single-cell-derived basal colonies can repopulate a mammary gland when transplanted in vivo. This indicates that a high proportion of basal myoepithelial cells can give rise to a mammary repopulating unit (MRU). We demonstrate that myoepithelial cells, flow-sorted using two independent myoepithelial-specific reporter strategies, have MRU capacity. Using an inducible lineage-tracing approach we follow the progeny of myoepithelial cells that express α-smooth muscle actin and show that they function as long-lived lineage-restricted stem cells in the virgin state and during pregnancy.This work was funded by Cancer Research UK, Breast Cancer Campaign, the University of Cambridge, Hutchison Whampoa Limited, La Ligue Nationale Contre le Cancer (Equipe Labelisée 2013) and a grant from Agence Nationale de la Recherche ANR- 08-BLAN-0078-01 to M.A.G.This is the author accepted manuscript. The final version is available from Nature at http://www.nature.com/ncb/journal/vaop/ncurrent/full/ncb3025.html
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