22,181 research outputs found
Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point
The propagation of linear Alfvén wave pulses in an inhomogeneous plasma near a 2D coronal null point is investigated. When a uniform plasma density is considered, it is seen that an initially planar Alfvén wavefront remains planar, despite the varying equilibrium Alfvén speed, and that all the wave collects at the separatrices. Thus, in the non-ideal case, these Alfvénic disturbances preferentially dissipate their energy at these locations. For a non-uniform equilibrium density, it is found that the Alfvén wavefront is significantly distorted away from the initially planar geometry, inviting the possibility of dissipation due to phase mixing. Despite this however, we conclude that for the Alfvén wave, current density accumulation and preferential heating still primarily occur at the separatrices, even when an extremely non-uniform density profile is considered
Maternal morbidity after childbirth in a health care facility in south - South Nigeria
Background: Maternal morbidity though a global public health problem had not been a major Subject of emphasis like maternal mortality. And yet for each woman that dies sixteen others Suffer various forms of morbidity.Objective: This study was design to determine the incidence, types and determinants of maternal morbidity after childbirth in a health care facility in south-south Nigeria.Methodology: This study was a retrospective review of delivery records of women who were treated at the maternity unit of the Holy Family Hospital, Ikom, Cross-Rivers State, Nigeria from January 2004 to December 2010.Results: Among the 3,068 deliveries, 124(4.04%) women suffered various morbidities. Most (31.5%) were aged 26 to 30 years. Sixty seven (54.0%) had at least secondary level of education. About 38.0% had no occupation. Unbooked (53.2%) and Para 3 to 4 (54.0%) were in the majority. The leading morbidities were; postpartum heamorrhage (33.9%), retained placenta (25.0%), hypertensive disorders (14.5%) and genital sepsis (13.7%). Educated women were more likely to book for antenatal care (p=0.000) and to deliver in orthodox health facility (p=0.007).Themorbidities were significantly related to the level of skill of the birth attendants (p=0.001) and place of delivery (P=0.045). Majority (85.5%) of the patients were treated as in-patients for a week.Conclusion: The incidence of maternal morbidity was high with postpartum haemorrhage, retained placenta, hypertensive disorders and genital sepsis as the leading morbidities. Sustaining the campaign for women education,utilization of reproductive health services, promoting the employment of skilled birth attendants and hospital delivery is recommended.Keywords: Maternal morbidity, postpartum haemorrhage, puerperal sepsis, hypertension, childbirth
Information Security as Strategic (In)effectivity
Security of information flow is commonly understood as preventing any
information leakage, regardless of how grave or harmless consequences the
leakage can have. In this work, we suggest that information security is not a
goal in itself, but rather a means of preventing potential attackers from
compromising the correct behavior of the system. To formalize this, we first
show how two information flows can be compared by looking at the adversary's
ability to harm the system. Then, we propose that the information flow in a
system is effectively information-secure if it does not allow for more harm
than its idealized variant based on the classical notion of noninterference
Structural phase transition in IrTe: A combined study of optical spectroscopy and band structure calculations
IrPtTe is an interesting system showing competing phenomenon
between structural instability and superconductivity. Due to the large atomic
numbers of Ir and Te, the spin-orbital coupling is expected to be strong in the
system which may lead to nonconventional superconductivity. We grew single
crystal samples of this system and investigated their electronic properties. In
particular, we performed optical spectroscopic measurements, in combination
with density function calculations, on the undoped compound IrTe in an
effort to elucidate the origin of the structural phase transition at 280 K. The
measurement revealed a dramatic reconstruction of band structure and a
significant reduction of conducting carriers below the phase transition. We
elaborate that the transition is not driven by the density wave type
instability but caused by the crystal field effect which further
splits/separates the energy levels of Te (p, p) and Te p bands.Comment: 16 pages, 5 figure
Recommended from our members
Adhesion and cleaning of foods with complex structure: Effect of oil content and fluoropolymer coating characteristics on the detachment of cake from baking surfaces
The effect of surface coating on the detachment of a complex microstructured food material, was investigated using an improved version of the millimanipulation device described by Ali et al. (2015 \textit{Food & Bioproducts Processing}, Vol. 93, 256–268). The test material was baked sponge cake batter, which contains approximately 27 vol% bubbles in a ‘continuous’ phase of emulsified oil in a flour/syrup suspension. Detachment in the dry state was studied for aluminium, 304 stainless steel and seven different fluoropolymer coatings. The surfaces differed in surface energy and roughness. The shear force required to detach baked cake, the work done, and the mass of residue remaining on the surface were measured. Virtually all samples detached by cohesive or mixed failure, where adhesion to the surface was stronger than or comparable with cohesive interactions within the cake. The shear force was almost independent of surface composition, energy and roughness, but strongly related to the oil content of the cake. The mass of residue was found to be linearly dependent on the calculated work of adhesion of oil to the surface in an aqueous environment. The quantitative findings are consistent with confocal microscopy images of uncooked batter contacting polar and non-polar surfaces which show very different oil spreading behaviour at the batter-substrate interface. The ability of oil to replace water from a surface is shown to be a key factor determining adhesion of these materials.A Jardine Postgraduate Scholarship for YL from the Jardine Foundation and a PhD studentship for OMM from Du Pont/Chemours and is gratefully acknowledged
Perforin-mediated cytotoxicity is critical for surveillance of spontaneous lymphoma
Immune surveillance by cytotoxic lymphocytes against cancer has been postulated for decades, but direct evidence for the role of cytotoxic lymphocytes in protecting against spontaneous malignancy has been lacking. As the rejection of many experimental cancers by cytotoxic T lymphocytes and natural killer cells is dependent on the pore-forming protein perforin (pfp), we examined pfp-deficient mice for increased cancer susceptibility. Here we show that pfp-deficient mice have a high incidence of malignancy in distinct lymphoid cell lineages (T, B, NKT), indicating a specific requirement for pfp in protection against lymphomagenesis. The susceptibility to lymphoma was accentuated by simultaneous lack of expression of the p53 gene, mutations in which also commonly predispose to human malignancies, including lymphoma. In contrast, the incidence and age of onset of sarcoma was unaffected in p53-deficient mice. Pfp-deficient mice were at least 1,000-fold more susceptible to these lymphomas when transplanted, compared with immunocompetent mice in which tumor rejection was controlled by CD8(+) T lymphocytes. This study is the first that implicates direct cytotoxicity by lymphocytes in regulating lymphomagenesis
Use of ultrasound elasticity imaging to monitor the response of a primary breast cancer to neoadjuvant chemotherapy in one patient in a pilot study
Polymorphism in TGFB1 is associated with worse non-relapse mortality and overall survival after stem cell transplantation with unrelated donors.
Transforming growth factor beta-1, encoded by the TGFB1 gene, is a cytokine that plays a central role in many physiological and pathogenic processes. We have sequenced TGFB1 regulatory region and assigned allelic genotypes in a large cohort of hematopoietic stem cell transplantation patients and donors. In this study, we analyzed 522 unrelated donor-patient pairs and examined the combined effect of all the common polymorphisms in this genomic region. In univariate analysis, we found that patients carrying a specific allele, 'p001', showed significantly reduced overall survival (5-year overall survival 30.7% for p001/ p001 patients vs. 41.6% others; P=0.032) and increased non-relapse mortality (1-year nonrelapse mortality: 39.0% vs. 25.4%; P=0.039) after transplantation. In multivariate analysis, the presence of a p001/ p001 genotype in patients was confirmed as an independent factor for reduced overall survival [hazard ratio=1.53 (1.04-2.24); P=0.031], and increased non-relapse mortality [hazard ratio=1.73 (1.06-2.83); P=0.030]. In functional experiments we found a trend towards a higher percentage of surface transforming growth factor beta-1-positive regulatory T cells after activation when the cells had a p001 allele (P=0.07). Higher or lower production of transforming growth factor beta-1 in the inflammatory context of hematopoietic stem cell transplantation may influence the development of complications in these patients. Findings indicate that TGFB1 genotype could potentially be of use as a prognostic factor in hematopoietic stem cell transplantation risk assessment algorithms
- …