1,139 research outputs found

    Crystalline Polymers with Exceptionally Low Thermal Conductivity Studied using Molecular Dynamics

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    Semi-crystalline polymers have been shown to have greatly increased thermal conductivity compared to amorphous bulk polymers due to effective heat conduction along the covalent bonds of the backbone. However, the mechanisms governing the intrinsic thermal conductivity of polymers remain largely unexplored as thermal transport has been studied in relatively few polymers. Here, we use molecular dynamics simulations to study heat transport in polynorbornene, a polymer that can be synthesized in semi-crystalline form using solution processing. We find that even perfectly crystalline polynorbornene has an exceptionally low thermal conductivity near the amorphous limit due to extremely strong anharmonic scattering. Our calculations show that this scattering is sufficiently strong to prevent the formation of propagating phonons, with heat being instead carried by non-propagating, delocalized vibrational modes known as diffusons. Our results demonstrate a mechanism for achieving intrinsically low thermal conductivity even in crystalline polymers that may be useful for organic thermoelectrics

    Psychological type and the pulpit : an empirical enquiry concerning preachers and the SIFT method of biblical hermeneutics

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    A sample of 389 experienced preachers completed a measure of psychological type. They then read Mark 1:29-39 and recorded their evaluations of the four reflections on this passage proposed by Francis (1997) and which were derived from the SIFT method of biblical hermeneutics and liturgical preaching. Three main conclusions are drawn from these data. First, compared with the United Kingdom population norms, preachers within this sample were significantly more likely to prefer introversion, intuition, feeling and judging. Second, preachers were four times more likely to prefer a sensing interpretation of the text rather than a thinking interpretation, emphasising the richness of the narrative rather than facing the theological questions posed by it. Third, there was little evidence to suggest that preachers were less likely to appreciate interpretations consonant with their less preferred or inferior function than those consonant with their most preferred or dominant function. In this sense, the richness of the SIFT method should be accessible to preachers of all psychological types

    Synergistic Inhibition of Resistant Enterobacteriaceae Using a Possible Klebsiella Secreted Bacteriocin with Broad-Spectrum Antibiotic

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    Due to the increasing prevalence of multi-drug resistant (MDR) bacteria, it is now important to begin the search for novel means of defending against such resistant infections. Enterobacteriaceae is a clinically relevant family of bacteria that has shown extensive resistance to many antibiotics, especially after biofilm formation. Inhibitory poly-microbial interactions within this family have been observed. It is known that Citrobacter freundii (CF) growth is significantly inhibited by Klebsiella pneumoniae (KP) through a secreted protein. In this study, the potential KP bacteriocin was screened for its inhibitory effects on CF at various phases of biofilm development. The suspected KP bacteriocin was also tested for its ability to decrease the dosage of antibiotics necessary to inhibit CF growth. Using spectrophotometric analysis, it was shown that the combined treatment of streptomycin and the KP protein allowed a decrease in the minimum inhibitory concentration of streptomycin needed from 50 μM to 32 μM. The combined treatment also yielded increased inhibition at the initial attachment phase of CF infection, as well as after biofilm development. The study uses the secreted KP protein to show the use of poly-microbial interactions within clinical applications. Future projects concerning this KP molecule can pursue the use of a C. elegans model to determine its efficacy in vitro

    Psychological type profile of Roman Catholic priests : an empirical enquiry in the United States

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    This study explores the psychological type profile of Roman Catholic priests serving in the United States, drawing on data provided by 55 priests who completed the Francis Psychological Type Scales. The data demonstrated clear preferences for introversion (67 %), sensing (64 %), and judging (91 %), and for a balance between thinking (49 %) and feeling (51 %). A very high proportion of priests reported preferences for ISTJ (27 %), compared with 16 % of men in the U.S. population. Implications of these findings are discussed for ministry in the Roman Catholic Church

    Sensitivity and resolution in 19F and 15N solid-state NMR: applications to pharmaceutical systems

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    This thesis describes a study into the improvement of solid-state NMR methods for the detection and characterisation of pharmaceutical compound. Chapter 1 reviews the literature that are relevant to the techniques discussed within this thesis Chapter 2 outlines the key experimental techniques employed within this work. Chapter 3 investigates the usefulness of indirect detection as a method to detect and possibly quantify the ratio of 15N present for multiple 15N containing systems. The work highlights how for CP performed at fast MAS, there is a much greater sensitivity to the RF inhomogeneity of the probe, and how this be reduced by using ramped CP. The results showed that for routine detection of 15N it is advised to detect via routine CP, due to the more complex setup of indirect detection. Chapter 4 discusses the potential of combining REDOR data and that of powder X-ray diffraction as a method to improve the efficiency of structural determination of powders. The investigation was performed on two pseudo-polymorphs with the aim of measuring differences in the 13C-19F couplings. The aim was that many ‘loose constraints’ could be used to improve efficiency when working with natural abundance 13C. Chapter 5 for 19F, a large number of model compounds were selected to reflect the broad range of possible fluorine environments, ranging from per-fluorinated systems where the line-width is dominated by homonuclear coupling to systems dilute in 19F when the total line-width is found to be determined by the hetero-nuclear decoupling as well as in-homogenous contribution. Combining the data from the model compounds it has led to a better understanding the factors that determine 19F resolution. As such a suitable work scheme in order to achieve the best resolution for 19F containing compounds is presented. Chapter 6 investigates the combination of NMR and calculated data in order to assign chemical shifts to specific crystal sites1. The results show that by combining ab initio calculations with 2D NMR data confident assignment of peaks is possible. (1) Robbins, A. J.; Ng, W. T. K.; Jochym, D.; Keal, T. W.; Clark, S. J.; Tozer, D. J.; Hodgkinson, P. Phys. Chem. Chem. Phys. 2007, 9, 2389

    How homonegative is the typical Anglican congregation? : applying the Robbins-Murray Religious Homonegative Orientation Scale (RHOS)

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    This paper set out to assess and profile attitudes toward homosexuality within one typical Anglican congregation. The majority of attendees (n=65, 42% men and 58% women) completed the Robbins-Murray Religious Homonegative Orientation Scale (an instrument embracing the following views on homosexuality: theological aspects, normativity, moral judgement, legal proscription, and affective response), together with indices concerned with demographic factors, religious factors and personality factors. Overall, the data demonstrated that the majority of churchgoers did not espouse a negative view of homosexuality. More proscriptive attitudes were associated with being male, with being older, with regular attendance, and with being more conservative. Individual differences in personality, however, were not significant predictors of views on homosexuality

    Some tree-level string amplitudes in the NSR formalism

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    We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point functions involving bosons and fermions. We calculate the five-point amplitude for massless gluons and find agreement with an earlier result by Brandt, Machado and Medina. We then compute the five-point amplitudes involving two and four fermions respectively, the general form of which has not been previously obtained in the NSR formalism. The results nicely confirm expectations from the supersymmetric F4F^4 effective action. Finally we use the prescription of Kawai, Lewellen and Tye (KLT) to compute the amplitudes for the closed string sector.Comment: 40+8 pages; v2: references added; v3: additional field theory checks made; published version; v4: minor corrections; results unchange

    Democracy in Crisis: Corruption, Media, and Power in Turkey

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    In November 2013, a Freedom House delegation traveled to Turkey to meet with journalists, NGOs, business leaders, and senior government officials about the deteriorating state of media freedom in the country. The delegation's objective, and the plan for this report, was to investigate reports of government efforts to pressure and intimidate journalists and of overly close relationships between media owners and government, which, along with bad laws and overly aggressive prosecutors, have muzzled objective reporting in Turkey.Since November, events in Turkey have taken a severe turn for the worse. The police raids that revealed a corruption scandal on December 17, and the allegations of massive bidrigging and money laundering by people at the highest levels of the government, have sparked a frantic crackdown by the ruling Justice and Development (AK) Party. More journalists have been fired for speaking out. Hundreds of police officers and prosecutors have been fired or relocated across the country. Amendments to the new Internet regulation law proposed by the government would make it possible for officials to block websites without court orders. The government is also threatening the separation of powers by putting the judiciary, including criminal investigations, under direct control of the Ministry of Justice. The crisis of democracy in Turkey is not a future problem -- it is right here, right now.This report on the media recognizes that what is happening in Turkey is bigger than one institution and part of a long history that continues to shape current events. The media in Turkey have always been close to the state; as recently as 1997, large media organizations were co-opted by the military to subvert a democratically elected government. The AK Party was formed in the wake of those events. But even as it has tamed the military, the AKP has been unable to resist the temptations of authoritarianism embedded in the state the military helped create. Over the past seven years, the government has increasingly employed a variety of strong-arm tactics to suppress the media's proper role as a check on power. Some of the most disturbing efforts include the following:Intimidation: Prime Minister Recep Tayyip Erdo?an frequently attacks journalists by name after they write critical commentary. In several well-known cases, like those of Hasan Cemal and Nuray Mert, journalists have lost their jobs after these public attacks. Sympathetic courts hand out convictions in defamation cases for criticism.Mass firings: At least 59 journalists were fired or forced out in retaliation for their coverage of last summer's Gezi Park protests. The December corruption scandal has produced another string of firings of prominent columnists.Buying off or forcing out media moguls: Holding companies sympathetic to the government receive billions of dollars in government contracts, often through government bodies housed in the prime minister's office. Companies with media outlets critical of the government have been targets of tax investigations, forced to pay large fines, and likely disadvantaged in public tenders.Wiretapping: The National Security Organization has wiretapped journalists covering national security stories, using false names on the warrants in order to avoid judicial scrutiny.Imprisonment: Dozens of journalists remain imprisoned under broadly defined antiterrorism laws. A majority of those in prison are Kurds, and some analysts believe the government is using them as bargaining chips in negotiations with the Kurdish PKKThese tactics are unacceptable in a democracy. They deny Turkish citizens full access to information and constrain a healthy political debate. Journalists and government officials alike acknowledge that reporters and news organizations have practiced self-censorship to avoid angering the government, and especially Prime Minister Erdogan.The intentional weakening of Turkey's democratic institutions, including attempts to bully and censor Turkey's media, should and must be a matter of deep concern for the United States and the European Union. As the AKParty's internal coalition has grown more fragile, Erdogan has used his leverage over the media to push issues of public morality and religion and to squelch public debate of the accountability of his government. The result is an increasingly polarized political arena and society.Freedom House calls on the government of Turkey to recognize that in a democracy, a free press and other independent institutions play a very important role. There are clear and concrete steps the Turkish government must take to end the intimidation and corruption of Turkey's media. Chief among these are the following:Cease threats against journalists.Repeal the criminal defamation law and overly broad antiterrorism and "criminal organization" laws that have been used to jail dozens of journalists.Comply with European and international standards in procurement practices in order to reduce the incentive for media owners to curry favor by distorting the news. Turkish media owners themselves must make a commitment to support changes in procurement practices if they are to win back the trust of Turkey's citizens.Although building a resilient democracy is fundamentally up to Turkish citizens, the international community cannot afford to be bystanders. The European Union and the OSCE have raised strong concerns about government pressure on Turkey's media, and the EU's warnings against governmental overreach have been pointed. Unfortunately, the same cannot be said for the United States. The Obama administration has been far too slow to realize the seriousness of the threat to Turkey's democracy. U.S. criticism of the Turkish government's recent actions has come from the State Department spokesperson and White House press secretary, not from the high-ranking officials who need to be engaged in responding to a crisis of this scale. Where European governments and institutions have been specifically and publicly engaged with the government over the crisis, the Obama administration has avoided the difficult issues. It is time to speak frankly and with seriousness about the growing threat to democracy in Turkey, and to place freedom of expression and democracy at the center of the policy relationship

    Localized states in the conserved Swift-Hohenberg equation with cubic nonlinearity

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    The conserved Swift-Hohenberg equation with cubic nonlinearity provides the simplest microscopic description of the thermodynamic transition from a fluid state to a crystalline state. The resulting phase field crystal model describes a variety of spatially localized structures, in addition to different spatially extended periodic structures. The location of these structures in the temperature versus mean order parameter plane is determined using a combination of numerical continuation in one dimension and direct numerical simulation in two and three dimensions. Localized states are found in the region of thermodynamic coexistence between the homogeneous and structured phases, and may lie outside of the binodal for these states. The results are related to the phenomenon of slanted snaking but take the form of standard homoclinic snaking when the mean order parameter is plotted as a function of the chemical potential, and are expected to carry over to related models with a conserved order parameter.Comment: 40 pages, 13 figure
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