Genres of Spam

Spam is currently the dominant form of communications on the internet, accounting for most e-mail traffic. Spam is a marketing device, it is also an expensive and time-consuming nuisance for industrires as well as a major vehicle for serious internet crimes. While considerable research has focused on the technical aspects of spam, how it works and how it can be blocked, our research aims to better understand why it works. We explore how genre theory can contribute to our understanding of ‘spam’. Our study consists of two parts. The first examined the content, form and specific features and considered the manifest relationship to existing genres of communication. The second part of the study focused on a detailed analysis of 111 Nigerian letters, a particularly noxious form of spam. Genre is generally considered useful because it makes communications more recognizable and understandable to recipients, helping readers process information. Our study suggests that spam is not a single genre but adaptations of many recognizable print genres. With spam, genre operates at several levels and is often used to mask rather than reveal intent. The paper concludes that spam exploits genre by conforming to known forms while at the same time breaching those norms

Dynamics of spin-2 Bose condensate driven by external magnetic fields

Dynamic response of the F=2 spinor Bose-Einstein condensate (BEC) under the influence of external magnetic fields is studied. A general formula is given for the oscillation period to describe population transfer from the initial polar state to other spin states. We show that when the frequency and the reduced amplitude of the longitudinal magnetic field are related in a specific manner, the population of the initial spin-0 state will be dynamically localized during time evolution. The effects of external noise and nonlinear spin exchange interaction on the dynamics of the spinor BEC are studied. We show that while the external noise may eventually destroy the Rabi oscillations and dynamic spin localization, these coherent phenomena are robust against the nonlinear atomic interaction.Comment: 16 pages, 7 figures. accepted by Phys. Rev.

Cirurgia de revascularização do miocárdio: complicações pleuro-pulmonares agudas caracterizadas por tomografia computadorizada de tórax

INTRODUCTION: Pleuropulmonary changes are common following coronary artery bypass grafting surgery performed with a saphenous vein graft, with or without an internal mammary artery. The presence of atelectasis or pleural effusions reflects the thoracic trauma. PURPOSE: To define the postoperative incidence of changes in the lung and in the pleural space and to evaluate the influence of the trauma. METHODS: Thirty patients underwent elective coronary artery bypass grafting surgery (8 saphenous vein grafts and 22 saphenous vein grafts and internal mammary artery grafts with pleurotomy). Chest tubes in the left pleural space were used in all internal mammary artery patients. On the second (day 2) and seventh (day 7) postoperative day, patients underwent a computed tomography, and pleural effusions were rated as follows: grade 0 = no fluid to grade 4 = fluid in more than 75% of the hemithorax. Atelectasis was rated as follows: laminar = 1, segmental = 3, and lobar = 10 points. RESULTS: All patients had pleural effusion or atelectasis. Between day 2 and day 7, the number of patients with effusions or atelectasis on the right side decreased (P < 0.05). The incidence of effusions on day 2 in the saphenous vein graft group (87.5%) was higher (P < 0.05) than in the internal mammary artery group (52.3%). The incidence of atelectasis in the lower right lobe decreased (P < 0.05) from 86.7% (day 2) to 26.7% (day 7). The degree of atelectasis in both sides did not differ on day 2 (P = 0.42) but did on day 7 (P < 0.0001). There was a decrease in the atelectasis from day 2 to day 7 on the right side (P < 0.001), but not on the left (P = 0.21). On day 2 there was a relationship between atelectasis and effusion on the right (P = 0.04), but not on the left (P = 0.113). CONCLUSION: The present series demonstrates that there is a high incidence of both minimal pleural effusion and atelectasis after coronary artery bypass grafting surgery, which drops on the right side from day 2 to day 7 post surgery. Factors that contribute to the persistence of changes on the left side include the thoracic trauma and the presence of chest tubes and pericardial effusion.INTRODUÇÃO: O comprometimento pleuro-pulmonar é freqüente após cirurgia de revascularização do miocárdio independente do uso de veia safena ou de artéria mamária interna. A presença de atelectasias e derrame pleural tem sido atribuída ao trauma torácico. OBJETIVOS: Definir a incidência do comprometimento pleuro-pulmonar observado através de tomografia computadorizada, analisando a influência do trauma no desenvolvimento destas complicações. MÉTODOS: Trinta pacientes foram submetidos a cirurgia eletiva de revascularização do miocárdio (8 safena e 22 também mamária com pleurotomia). Foi drenada a cavidade pleural esquerda de todos os pacientes do grupo mamária. Realizada Tomografia Computadorizada do tórax no 2º e 7º dias pós-op, avaliando-se o derrame pleural (0: sem líquido e 4: derrame em mais de 75% do hemitórax) e atelectasias (laminar: 1, segmentar: 3 e lobar: 10 pontos). RESULTADOS: Todos os pacientes apresentaram derrame pleural ou atelectasia. Entre o 2º e o 7º dia, o número de pacientes com derrame ou com atelectasia, no lado direito, diminuiu (p < 0.05). A prevalência de derrames, no 2º dia, no grupo safena, (87.5%) foi maior (p < 0.05) do que no grupo mamária (52.3%). A prevalência de atelectasias no lobo inferior direito diminuiu (p < 0.05) de 86.7% (2º dia) para 26.7% (7º dia). O grau de atelectasias, em ambos os lados, não diferiu no dia 2 (p = 0,42) mas sim no dia 7 (p < 0.0001). Houve diminuição das atelectasias do dia 2 para o 7, à direita (p < 0.001), mas não à esquerda (p = 0.21). Houve correlação (dia 2) entre as atelectasias e os derrames à direita (p = 0.04), mas não à esquerda (p = 0.113). CONCLUSÃO: Este estudo evidencia alta prevalência de derrame pleural e atelectasias após cirurgia de revascularização do miocárdio, que se reduz à direita no 7º dia de pós-operatório. Os fatores envolvidos na persis-tência das alterações à esquerda incluem o maior trauma torácico, ressaltando-se a drenagem e a presença de derrame pericárdico

Effects of a Protein Preload on Gastric Emptying, Glycemia, and Gut Hormones After a Carbohydrate Meal in Diet-Controlled Type 2 Diabetes

OBJECTIVE: We evaluated whether a whey preload could slow gastric emptying, stimulate incretin hormones, and attenuate postprandial glycemia in type 2 diabetes. RESEARCH DESIGN AND METHODS: Eight type 2 diabetic patients ingested 350 ml beef soup 30 min before a potato meal; 55 g whey was added to either the soup (whey preload) or potato (whey in meal) or no whey was given. RESULTS: Gastric emptying was slowest after the whey preload (P < 0.0005). The incremental area under the blood glucose curve was less after the whey preload and whey in meal than after no whey (P < 0.005). Plasma glucose-dependent insulinotropic polypeptide, insulin, and cholecystokinin concentrations were higher on both whey days than after no whey, whereas glucagon-like peptide 1 was greatest after the whey preload (P < 0.05). CONCLUSIONS: Whey protein consumed before a carbohydrate meal can stimulate insulin and incretin hormone secretion and slow gastric emptying, leading to marked reduction in postprandial glycemia in type 2 diabetes.Jing Ma, Julie E. Stevens, Kimberly Cukier, Anne F. Maddox, Judith M. Wishart, Karen L. Jones, Peter M. Clifton, Michael Horowitz, and Christopher K. Rayne

Photoabsorption and photoion spectroscopy of atomic uranium in the region of 6p and 5d excitations

The photoabsorption process in atomic uranium has been investigated experimentally and theoretically in the 15–150-eV region. Using the dual laser plasma technique, the 6p photoabsorption spectrum has been recorded while for the first time the 5d region has been remeasured photoelectrically using both photoabsorption and photoion spectroscopy. Interpretation of the photoabsorption spectra is supported by Hartree-Fock calculations which take into account spin-flip decay and the interaction of many discrete states with many continua. The 6p spectrum is entirely dominated by spin-orbit split 6p⃗6d transitions. The 5d-subshell photoabsorption is shown to consist predominantly of discrete 5d⃗5f excitations; here the electrostatic and spin-orbit interactions are comparable in strength

Molecular basis of FIR-mediated c-myc transcriptional control

The far upstream element (FUSE) regulatory system promotes a peak in the concentration of c-Myc during cell cycle. First, the FBP transcriptional activator binds to the FUSE DNA element upstream of the c-myc promoter. Then, FBP recruits its specific repressor (FIR), which acts as an on/off transcriptional switch. Here we describe the molecular basis of FIR recruitment, showing that the tandem RNA recognition motifs of FIR provide a platform for independent FUSE DNA and FBP protein binding and explaining the structural basis of the reversibility of the FBP-FIR interaction. We also show that the physical coupling between FBP and FIR is modulated by a flexible linker positioned sequentially to the recruiting element. Our data explain how the FUSE system precisely regulates c-myc transcription and suggest that a small change in FBP-FIR affinity leads to a substantial effect on c-Myc concentration.MRC Grant-in-aid U11757455

Electron energy loss and induced photon emission in photonic crystals

The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field. The features of the energy loss spectra are shown to be related to the photonic band structure of the crystal. Two different regimes are discussed: for small lattice constants $a$ relative to the wavelength of the associated electron excitations $\lambda$, an effective medium theory can be used to describe the material; however, for $a\sim\lambda$ the photonic band structure plays an important role. Special attention is paid to the frequency gap regions in the latter case.Comment: 12 pages, 7 figure

Phase diffusion as a model for coherent suppression of tunneling in the presence of noise

We study the stabilization of coherent suppression of tunneling in a driven double-well system subject to random periodic $\delta-$function ``kicks''. We model dissipation due to this stochastic process as a phase diffusion process for an effective two-level system and derive a corresponding set of Bloch equations with phase damping terms that agree with the periodically kicked system at discrete times. We demonstrate that the ability of noise to localize the system on either side of the double-well potenital arises from overdamping of the phase of oscillation and not from any cooperative effect between the noise and the driving field. The model is investigated with a square wave drive, which has qualitatively similar features to the widely studied cosinusoidal drive, but has the additional advantage of allowing one to derive exact analytic expressions.Comment: 17 pages, 4 figures, submitted to Phys. Rev.

Understanding Uncertainties in Model-Based Predictions of Aedes aegypti Population Dynamics

Dengue is one of the most important insect-vectored human viral diseases. The principal vector is Aedes aegypti, a mosquito that lives in close association with humans. Currently, there is no effective vaccine available and the only means for limiting dengue outbreaks is vector control. To help design vector control strategies, spatial models of Ae. aegypti population dynamics have been developed. However, the usefulness of such models depends on the reliability of their predictions, which can be affected by different sources of uncertainty including uncertainty in the model parameter estimation, uncertainty in the model structure, measurement errors in the data fed into the model, individual variability, and stochasticity in the environment. This study quantifies uncertainties in the mosquito population dynamics predicted by Skeeter Buster, a spatial model of Ae. aegypti, for the city of Iquitos, Peru. The uncertainty quantification should enable us to better understand the reliability of model predictions, improve Skeeter Buster and other similar models by targeting those parameters with high uncertainty contributions for further empirical research, and thereby decrease uncertainty in model predictions

SHIFTING THE PARADIGM IN RADIATION SAFETY

The current radiation safety paradigm using the linear no-threshold (LNT) model is based on the premise that even the smallest amount of radiation may cause mutations increasing the risk of cancer. Autopsy studies have shown that the presence of cancer cells is not a decisive factor in the occurrence of clinical cancer. On the other hand, suppression of immune system more than doubles the cancer risk in organ transplant patients, indicating its key role in keeping occult cancers in check. Low dose radiation (LDR) elevates immune response, and so it may reduce rather than increase the risk of cancer. LNT model pays exclusive attention to DNA damage, which is not a decisive factor, and completely ignores immune system response, which is an important factor, and so is not scientifically justifiable. By not recognizing the importance of the immune system in cancer, and not exploring exercise intervention, the current paradigm may have missed an opportunity to reduce cancer deaths among atomic bomb survivors. Increased antioxidants from LDR may reduce aging-related non-cancer diseases since oxidative damage is implicated in these. A paradigm shift is warranted to reduce further casualties, reduce fear of LDR, and enable investigation of potential beneficial applications of LDR