Generation and breakdown of aerodynamic lift: Physical mechanism

A contribution is given to an old problem: the explanation of the generation of aerodynamic lift. Physical models are described which provide a better understanding of the phenomena involved

The Effect of Artificial Sweeteners in Chewing Gum, Helpful or Harmful?

Objective/Aims: This review of literature was designed to analyze the effects of artificial sweeteners in chewing gum in the oral cavity. The intent was to recognize which formulations of artificial sweeteners in chewing gum lead to beneficial outcomes in the oral cavity and which formulations lead to harmful effects. Methods: The review of literature analyzed the conclusions of primary and secondary resources accumulated from PubMed. Multiple scholarly studies were filtered based upon meta-analysis, cross-sectional, and cohort studies. The following key terms were used: artificial sweetener, chewing gum, plaque, saliva, microbes, and oral health. A summative report was created based upon the relevant findings. Articles selected were published after 2014. Results: The studies collected were assessed using a measure of saliva and plaque pH, salivary function, caries occurrence, remineralization, and oral flora. Xylitol made the most beneficial impact on the oral cavity. Research indicates artificial sweeteners have shown an immense advantage over conventional sugar in chewing gum, and its resulting effects on hard tissue. Conclusion: The relationship between artificial sweeteners and oral health supports different advantageous outcomes in the oral cavity. In conclusion, although studies using artificial sweeteners can show benefits to the oral cavity, the dose of artificial sweetener required to yield these results are often not found in chewing gum.https://scholarscompass.vcu.edu/denh_student/1012/thumbnail.jp

Effect of Transition to the Dry Period on Fecal Shedding of Coliform Bacteria in Dairy Cows

On well-managed dairy farms, environmental mastitis leading to clinical mastitis (CM) in dairy cows is common, and the most likely cause identified is certain gram-negative bacteria. Clinical mastitis is a very costly disease for farmers, limiting milk production and saleable milk, as well as negatively affecting milk quality. Previous studies have shown that the dry period is a critical time in the development of new intramammary infections that persist into the next lactation. In some beef feedlot studies, large increases in grain have resulted in increased fecal shedding of E. coli bacteria. Cows are fed primarily a high grain diet and a forage-based diet in lactation and the dry period, respectively. Lactating cows are fed high levels of grain to support high milk yields. The high level of grain in late lactation may be associated with higher fecal shedding of bacteria compared to the dry period when lower levels of grain are fed. The objective of this study was to quantify the effect of a rapid change in grain levels in the diet by measuring fecal shedding in dairy cows before and after dry-off. Fecal samples, from cows at two dairy farms either one week before drying off (n = 25) or two weeks into the dry period (n = 30), were taken rectally and immediately plated on MacConkey agar plates, selecting for coliform bacteria. The numbers of coliform bacteria in the feces of cows were measured to quantify the shift in bacterial shedding counts as affected by the transition between lactation and dry-off. Results showed no change in coliform levels between late-lactation and the dry period (P = 0.78). Because high variability of coliform fecal shedding was seen between cows on each farm, detection of changes associated with grain feeding were likely masked; however, additional studies following cows through the transition from lactation to dry-off are needed to confirm.OARDC SEEDS GrantCFAES Honors Research GrantNo embargoAcademic Major: Animal Science

Der Heilige Ibis (Threskiornis aethiopicus) in Beverungen

Ein exotischer Gast versetzte im August 2011 die Beverunger Bevölkerung in Aufruhr. Zwischen den Enten am Weserkai stelzte plötzlich ein Ibis umher. Zunächst stand man beim NABU Holzminden und bei der Landschaftsstation im Kreis Höxter den Meldungen über die Sichtung des Schreitvogels skeptisch gegenüber. Denn Verwechslungen bei gemeldeten Raritäten aus der Vogelwelt sind nicht selten. Doch ein Ortstermin beseitigte schnell jeden Zweifel: Es war ein Heiliger Ibis (Threskiornis aethiopicus), dessen eigentliche Heimat sich über das südlich der Sahara befindliche Afrika erstreckt. Der Koloniebrüter ist als Neozoon in Frankreich, Spanien und Italien verbreitet, ferner gibt es einzelne kleinere Populationen in Nordamerika. Einzug erhielt der zu der Familie der Ibisse und Löffler zählende Vogel in diese Gebiete, wenn auch ungewollt, durch die Hilfe des Menschen. Durch sein elegantes Erscheinungsbild und seine Zutraulichkeit, aber auch bedingt durch den Mythos, den diese Spezies schon zur Zeit der Pharaonen umgab, war der Ibis ein willkommener Gast in zoologischen Gärten, in denen er in freifliegenden Kolonien gehalten wurde. Einigen Exemplaren gelang die Flucht, deren Nachfahren heute, zum Teil mit drastischen Folgen für andere Vogelarten, in freilebenden Populationen sowohl an den Küsten aber auch im urbanen Raum anzutreffen sind. Die Gefahr, die vom Ibis für andere Vogelarten ausgeht, besteht nicht darin, dass er den Lebensraum der einheimischen Arten besetzt, sondern darin, dass auf dem Speiseplan des Nahrungsopportunisten neben Wirbellosen, Amphibien und kleinen Fischen auch die Eier und Jungtiere anderer Seevögel stehen [YÉSOU & CLERGEAU 2005]. Bei dem Beverunger Ibis handelte es sich ebenfalls um einen Gefangenschaftsflüchtling. Ein deutliches Anzeichen dafür war der weiße Ring an seinem rechten Bein, aber auch seine Zutraulichkeit gegenüber dem durch ihn verursachten Zustrom neugieriger Besucher. Diese konnten den Ibis nicht nur aus nächster Nähe fotografieren sondern auch aus der Hand füttern

The bovine TRPV3 as a pathway for the uptake of Na+, Ca2+, and NH4+

Absorption of ammonia from the gastrointestinal tract results in problems that range from hepatic encephalopathy in humans to poor nitrogen efficiency of cattle with consequences for the global climate. Previous studies on epithelia and cells from the native ruminal epithelium suggest functional involvement of the bovine homologue of TRPV3 (bTRPV3) in ruminal NH4+ transport. Since the conductance of TRP channels to NH4+ has never been studied, bTRPV3 was overexpressed in HEK-293 cells and investigated using the patch-clamp technique and intracellular calcium imaging. Control cells contained the empty construct. Divalent cations blocked the conductance for monovalent cations in both cell types, with effects higher in cells expressing bTRPV3. In bTRPV3 cells, but not in controls, menthol, thymol, carvacrol, or 2-APB stimulated whole cell currents mediated by Na+, Cs+, NH4+, and K+, with a rise in intracellular Ca2+ observed in response to menthol. While only 25% of control patches showed single-channel events (with a conductance of 40.8 ± 11.9 pS for NH4+ and 25.0 ± 5.8 pS for Na+), 90% of bTRPV3 patches showed much larger conductances of 127.8 ± 4.2 pS for Na+, 240.1 ± 3.6 pS for NH4+, 34.0 ± 1.7 pS for Ca2+, and ~ 36 pS for NMDG+. Open probability, but not conductance, rose with time after patch excision. In conjunction with previous research, we suggest that bTRPV3 channels may play a role in the transport of Na+, K+, Ca2+ and NH4+ across the rumen with possible repercussions for understanding the function of TRPV3 in other epithelia

Anti-Americanism in Europe: Theoretical Mechanisms and Empirical Evidence

One of the most popular explanations for post-9/11 anti-Americanism argues that resentment against America and Americans is mainly a function of the US government's unpopular actions. The present article challenges this interpretation: first, it argues that neither the vitality of the resentment in times when the United States had no influence in the respective parts of the world nor its recent radical manifestations are accounted for in a political reductionist framework. In fact, specific traditions of anti-Americanism have an influence on the negative attitudes observed today, as a comparison between Britain, France, Germany, and Poland reveals. Second, this article suggests an alternative theoretical approach. Anti-Americanism can be explained by two basic mechanisms: it functions as a strategy to project denied and disliked self-concepts onto an external object, and it offers an interpretation frame for complex social processes that allows to reduce cognitive dissonance. Multivariate analyses based on empirical data collected in the Pew surveys of 2002 and 2007 show the fruitfulness of our theoretical approac

Are the affluent prepared to pay for the planet? Explaining willingness to pay for public and quasi-private environmental goods in Switzerland

A large number of ‘environmental justice' studies show that wealthier people are less affected by environmental burdens and also consume more resources than poorer people. Given this double inequity, we ask, to what extent are affluent people prepared to pay to protect the environment? The analyses are couched within the compensation/affluence hypothesis, which states that wealthier persons are able to spend more for environmental protection than their poorer counterparts. Further, we take into account various competing economic, psychological and sociological determinants of individuals' willingness to pay (WTP) for both public environmental goods (e.g., general environmental protection) and quasi-private environmental goods (e.g., CO2-neutral cars). Such a comprehensive approach contrasts with most other studies in this field that focus on a limited number of determinants and goods. Multivariate analyses are based on a general population survey in Switzerland (N=3,369). Although income has a positive and significant effect on WTP supporting the compensation hypothesis, determinants such as generalized interpersonal trust that is assumed to be positively associated with civic engagement and environmental concern prove to be equally important. Moreover, we demonstrate for the first time that time preferences can considerably influence survey-based WTP for environmental goods; since investments in the environment typically pay off in the distant future, persons with a high subjective discount rate are less likely to commi

Algorithm for Rapid Searching Among Star-Catalog Entries

An algorithm searches a star catalog to identify guide stars within the field of view of a telescope or camera. The algorithm is fast: the number of computations needed to perform the search is approximately proportional to the logarithm of the number of stars in the catalog. The algorithm requires the prior organization of the star catalog into a hierarchy utilizing independent spherical coverings (see figure), such that each successively higher level contains fewer elements. In the lowest and most numerous level of the hierarchy, the elements are individual stars in the star catalog. The next higher level contains a spherical covering (a constellation of n points on a sphere that minimizes the maximum distance of any point on the sphere from the closest one of the n points), the next higher level contains a smaller spherical covering, and so forth, ending at the highest level, which contains one element representing the point of entry into the search structure. With necessary exceptions at the lowest and highest levels, each element at each level is labeled in terms of the element to which it is linked in the next higher level and the first element to which it is linked in the next lower level. Each element is also labeled in terms of (1) its coordinates on the celestial sphere and (2) the largest angular distance to any element in any lower level in the hierarchy. The elements at all levels of the hierarchy are numbered on a single list, such that the elements of each constellation at each level are numbered consecutively. The algorithm is recursive. The input required to start the algorithm comprises the coordinates of a point on the celestial sphere. Attention is then focused on individual elements of the hierarchy, starting from the topmost one, as follows: The angle between the input point and the element under consideration is calculated. If the calculated angle is larger than the sum of (1) the predetermined angle to the most distant element plus (2) the half field of view of the telescope, then no stars will be within the field of view and this recursive part of the algorithm is terminated

To Pay or Not to Pay: Competing Theories to Explain Individuals’ Willingness to Pay for Public Environmental Goods

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Several theories have been proposed in an attempt to explain individuals’ willingness to pay (WTP) for public environmental goods. While most studies only take into account a single theory, this article discusses competing theories. These include, in addition to a basic economic model, the theory of public goods, Ajzen’s theory of planned behavior, and Schwartz’s norm-activation model. Empirical results are based on a contingent valuation study of biodiversity in German forests. Multivariate analyses demonstrate that studies using single theories omit crucial explanatory variables and, hence, might be misleading. Economic models of WTP have proven to be incomplete, that is, they have restricted explanatory power and need to be supplemented by psychological and sociological models. Furthermore, a general finding is that factors influencing WTP are different for “in-principle WTP” on the one hand and “amount of WTP (given in-principle WTP)” on the other. Income, for example, does not affect whether individuals are willing to pay at all, but significantly influences how much they are willing to pay