6,560 research outputs found
Gravitational Interactions and Fine-Structure Constant
Electromagnetic and gravitational central-field problems are studied with
relativistic quantum mechanics on curved space-time backgrounds. Corrections to
the transition current are identified. Analogies of the gravitational and
electromagnetic spectra suggest the definition of a gravitational
fine-structure constant. The electromagnetic and gravitational coupling
constants enter the Einstein-Hilbert-Maxwell Lagrangian. We postulate that the
variational principle holds with regard to a global dilation transformation of
the space-time coordinates. The variation suggests is consistent with a
functional relationship of the form alpha_QED being proportional to
alpha_G^(1/2), where alpha_QED is the electrodynamic fine-structure constant,
and alpha_G its gravitational analogue.Comment: 9 pages; LaTeX; Appeared in the Proceedings to the 17th Bled workshop
"What Comes Beyond the Standard Models", Bled, Slovenia, July 2-28, 2014;
Editors N. S. Mankoc Borstnik, H. B. Nielsen and D. Lukman; ISSN 1580-4992;
book series: Bled Workshops in Physics vol. 15, no. 2, pp. 115-122 (2014
Finding next-to-shortest paths in a graph
We study the problem of finding the next-to-shortest paths in a
graph. A next-to-shortest -path is a shortest -path
amongst -paths with length strictly greater than the length of
the shortest -path. In constrast to the situation in directed
graphs, where the problem has been shown to be NP-hard, providing edges of length zero are allowed,
we prove the somewhat surprising result that there is a polynomial
time algorithm for the undirected version of the problem
Exploring the Neuropeptides, Neuropeptide Receptors and Neurotransmitter Receptors in the Synganglia of Part-Fed Females of \u3ci\u3eOrnithodoros turicata\u3c/i\u3e (Argasidae) and \u3ci\u3eIxodes scapularis\u3c/i\u3e (Ixodidae) with Insights Into Their Roles in Contrasting Biology
The neurobiology of the synganglion (central nervous system) of the Lyme disease tick, Ixodes scapularis and the soft tick Ornithodoros turicata was evaluated using Illumina GAII high throughput sequencing which generated high coverage cDNA libraries (transcriptomes). These ticks exhibit different biological patterns of feeding, blood meal water, and salt elimination, cuticle plasticity versus cuticle synthesis, development and reproduction. RNA sequencing of I. scapularis, and Ornithodoros turicata yielded a total of 117,900,476 raw reads which were assembled to 30,838 contigs and a total of 63,528,102 also assembled to 132,258 contigs, respectively. Comparison of Gene Ontology (GO) mapping success for genes in 32 important GO molecular categories showed little difference between the two species.
Functional assignments of transcripts predicting neuropeptides, neuropeptide receptors and neurotransmitter receptors was done, supported by strong e-values (\u3c -6), and high consensus sequence alignments. For the synganglion of I. scapularis, transcripts predicting 23 neuropeptides and/or their receptors were identified. For the synganglion of O. turicata, 25 neuropeptides and/or their receptors were identified. Both species had transcripts predicting all of the same neuropeptides and/or their neuropeptide receptors in common except for allatotropin peptide, found only in I. scapularis, and allatostatin C, bursicon β, and glycoprotein B, which were found only in O. turicata.
If the repertoire of neuropeptide and neurotransmitter messages expressed in the synganglia of O. turicata and I scapularis is so similar, how can we explain the very different physiological processes that occur in these two very different tick species? Real time PCR assays were used to study the expression of candidate genes in response to blood feeding. My study shows a strong similarity in gene identity (annotation/alignments) of both species but marked differences in the gene expression, extent of up-regulation or down-regulation, and the timing of their expression in response to feeding. This may indeed help explain many of the differences in the biology of the two different species. The diversity of messages predicting important genes identified in this study and differences in their expression in response to feeding offers a valuable resource useful for understanding how the tick synganglion regulates important physiological functions in ticks
Maintaining social marketing\u27s relevance: a dualistic approach
There have been calls amongst academics and practitioners to move social marketing \u27upstream\u27. This paper attempts to clarify what upstream social marketing is, its appropriate relationship with ‘downstream’ social marketing and how both approaches can be combined into a suitable theoretical framework. The paper argues that neither up or downstream social marketing is superior and suggests that a dual, synergistic approach is needed. This argument is supported through reference to current social marketing interventions in the areas of road safety and childhood obesity. The paper concludes by suggesting that Polonsky, Carlson and Fry’s (2003) ‘harm chain’ concept may be a suitable mechanism to locate both approaches into a conceptual framework of practice
Idealized Antenna Patterns for Use in Communication-satellite Interference Studies
Idealized antenna patterns for communication satellite interference studie
Symptom relief with moderate dose chemotherapy (mitomycin-C, vinblastine and cisplatin) in advanced non-small cell lung cancer.
Twenty-four symptomatic patients with advanced non-small cell lung cancer (NSCLC) were treated with cisplatin-based chemotherapy (mitomycin-C 8 mg m-2 q 6 weeks, vinblastine 6 mg m-2 q 3 weeks, cisplatin 50 mg m-2 q 3 weeks). Patients were assessed for symptom relief as well as for objective response. Although only five patients achieved an objective response (21%), 18 patients (75%) reported a complete disappearance or good improvement in at least one of their tumour-related symptoms. The overall symptomatic response rate was 67% with 16 patients feeling better or much better on treatment. The toxicity of treatment (primarily myelosuppression and nausea and vomiting) was mild and hair loss was minimal. The high incidence of symptomatic relief seen in this study, even in the absence of objective response, suggests that moderate dose chemotherapy may have a role in the palliation of NSCLC
TESS: A Relativistic Hydrodynamics Code on a Moving Voronoi Mesh
We have generalized a method for the numerical solution of hyperbolic systems
of equations using a dynamic Voronoi tessellation of the computational domain.
The Voronoi tessellation is used to generate moving computational meshes for
the solution of multi-dimensional systems of conservation laws in finite-volume
form. The mesh generating points are free to move with arbitrary velocity, with
the choice of zero velocity resulting in an Eulerian formulation. Moving the
points at the local fluid velocity makes the formulation effectively
Lagrangian. We have written the TESS code to solve the equations of
compressible hydrodynamics and magnetohydrodynamics for both relativistic and
non-relativistic fluids on a dynamic Voronoi mesh. When run in Lagrangian mode,
TESS is significantly less diffusive than fixed mesh codes and thus preserves
contact discontinuities to high precision while also accurately capturing
strong shock waves. TESS is written for Cartesian, spherical and cylindrical
coordinates and is modular so that auxilliary physics solvers are readily
integrated into the TESS framework and so that the TESS framework can be
readily adapted to solve general systems of equations. We present results from
a series of test problems to demonstrate the performance of TESS and to
highlight some of the advantages of the dynamic tessellation method for solving
challenging problems in astrophysical fluid dynamics.Comment: ApJS, 197, 1
Exploring the Sources of Design Innovations: Insights from the Computer, Communications and Audio Equipment Industries
Whereas business research has focused on the impact of design innovations on market response and financial performance, the sources of design innovations, as opposed to those of technological innovations, have largely escaped investigation. In this research, we examine the organizational, financial, and environmental drivers of design innovations and how they contrast to technological innovations. Our study utilizes a unique dataset encompassing a 10-year window of innovation output drawn from the computer, communications, and audio and video equipment manufacturing industries. Our results suggest that design innovations are driven primarily by investments in research and development and slack organizational resources. Interestingly, we find that design innovations are more prevalent in smaller but fast-growing markets as opposed to technology innovations, which are prevalent in larger markets. Contrary to expectations, we find no association between marketing investments and design innovations. Our research contributes to the extant business literature by considering the sources of design innovations separately from the sources of technology innovations. We also contribute to the literature by distinguishing design and technology patents, developing a deeper understanding of design innovation, and illuminating a lesser understood source of competitive advantage for firms
Imaging of Skeletal Metastases in Myxoid Liposarcoma
Unlike other soft tissue sarcomas, myxoid/round cell liposarcoma (MRCL) has a tendency to spread to extrapulmonary sites but bone metastases are thought to be uncommon. In case reports, negative bone scintigraphy has been noted in patients with myxoid/round cell liposarcoma and bone metastases but the prevalence and optimal method of diagnosis of bone metastases in this common subtype of liposarcoma are unclear. In an attempt to answer these questions, data were obtained from a prospective database of patients with sarcoma, including MRCL, and the diagnostic imaging used was examined. A variety of imaging tools were used including plain X-rays, bone scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI). Eight patients (4.3%) developed skeletal metastases all of which were positive on MRI. Bone scintigraphy was negative in two out of four cases, CT was negative in six out of seven, and X-rays were negative in four. Radiography and CT measure mainly cortical bone involvement, whereas MRI examines bone marrow. When investigating patients with MRCL for bone pain, negative X-rays and bone scans do not rule out bone metastases. In our experience, MRI provides the most sensitive technique for the diagnosis of bone metastases in MRCL
Using an in vitro System for Maintaining Varroa Destructor Mites on Apis Mellifera Pupae as Hosts: Studies of Mite Longevity and Feeding Behavior
Varroa destructor mites (varroa) are ectoparasites of Apis mellifera honey bees, and the damage they inflict on hosts is likely a causative factor of recent poor honey bee colony performance. Research has produced an arsenal of control agents against varroa mites, which have become resistant to many chemical means of their control, and other means have uncertain efficacy. Novel means of control will result from a thorough understanding of varroa physiology and behavior. However, robust knowledge of varroa biology is lacking; mites have very low survivability and reproduction away from their natural environment and host, and few tested protocols of maintaining mites in vitro are available as standardized methods for varroa research. Here, we describe the \u27varroa maintenance system\u27 (VMS), a tool for maintaining in vitro populations of varroa on its natural host, and present best practices for its use in varroa and host research. Additionally, we present results using the VMS from research of varroa and host longevity and varroa feeding behavior. Under these conditions, from two trials, mites lived an average of 12 and 14 days, respectively. For studies of feeding behavior, female mites inflicted wounds located on a wide range of sites on the host\u27s integument, but preferred to feed from the host\u27s abdomen and thorax. Originally in the phoretic-phase, female mites in VMS had limited reproduction, but positive instances give insights into the cues necessary for initiating reproduction. The VMS is a useful tool for laboratory studies requiring long-term survival of mites, or host-parasite interactions
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