Dimer and N\'eel order-parameter fluctuations in the spin-fluid phase of the s=1/2 spin chain with first and second neighbor couplings

The dynamical properties at T=0 of the one-dimensional (1D) s=1/2 nearest-neighbor (nn) XXZ model with an additional isotropic next-nearest-neighbor (nnn) coupling are investigated by means of the recursion method in combination with techniques of continued-fraction analysis. The focus is on the dynamic structure factors S_{zz}(q,\omega) and S_{DD}(q,\omega), which describe (for q=\pi) the fluctuations of the N\'eel and dimer order parameters, respectively. We calculate (via weak-coupling continued-fraction analysis) the dependence on the exchange constants of the infrared exponent, the renormalized bandwidth of spinon excitations, and the spectral-weight distribution in S_{zz}(\pi,\omega) and S_{DD}(\pi,\omega), all in the spin-fluid phase, which is realized for planar $nn$ anisotropy and sufficiently weak nnn coupling. For some parameter values we find a discrete branch of excitations above the spinon continuum. They contribute to S_{zz}(q,\omega) but not to S_{DD}(q,\omega).Comment: RevTex file (7 pages), 8 figures (uuencoded ps file) available from author

On the Influence of Tools on Collaboration in Participative Enterprise Modeling – An Experimental Comparison between Whiteboard and Multi-Touch Table

The paper presents an experiment about the influence of the modeling tool on group work in the context of enterprise modeling. A goal modeling task was set where three groups of three persons worked with a whiteboard, and three groups of three persons worked with a multi-touch table. Comparisons of working styles between the two tools indicate that multi-touch tables promote parallel working and that a team member’s position plays a role in taking on certain tasks. Whiteboard users may more easily lose track of what teammates are doing

Theories for influencer identification in complex networks

In social and biological systems, the structural heterogeneity of interaction networks gives rise to the emergence of a small set of influential nodes, or influencers, in a series of dynamical processes. Although much smaller than the entire network, these influencers were observed to be able to shape the collective dynamics of large populations in different contexts. As such, the successful identification of influencers should have profound implications in various real-world spreading dynamics such as viral marketing, epidemic outbreaks and cascading failure. In this chapter, we first summarize the centrality-based approach in finding single influencers in complex networks, and then discuss the more complicated problem of locating multiple influencers from a collective point of view. Progress rooted in collective influence theory, belief-propagation and computer science will be presented. Finally, we present some applications of influencer identification in diverse real-world systems, including online social platforms, scientific publication, brain networks and socioeconomic systems.Comment: 24 pages, 6 figure

Efficacy of acupuncture in the treatment of chronic abdominal pain

Context: Abdominal pain is a widespread complaint and is one of the common reasons leading patients to seek medical care, either in emergency situations or with their primary providers. While acute abdominal pain is a better defined, usually surgical condition, chronic abdominal pain requires longer, typically lifelong, therapy. Chronic abdominal pain may also present with acute flares and complications. Here we review seminal and novel evidence discussing the use of acupuncture in the treatment of abdominal pain, indications, and conditions that may benefit from this approach. Evidence Acquisition: Chronic abdominal pain is a common complaint causing significant morbidity and disability and has a hefty price tag attached. Recent studies show it may be prevalent in as much as 25 of the adult population. It is defined as three episodes of severe abdominal pain over the course of three months. Chronic abdominal pain could be the result of chronicity of acute pain or of chronic pain syndromes, most commonly IBD syndromes and IBS. While a plethora of treatments exists for both conditions, these treatments usually fall short of complete symptom control, and there is a need for complementary measures to curb disability and increase the quality of life in these patients. Acupuncture is a form of integrative medicine that has long been used in Chinese and traditional medicine, based on the rebalancing of the patient�s Qi, or Ying/Yang balance. It has been shown to be effective in treating several other conditions, and novel evidence may expand its use into other fields as well. Clinical trials studying acupuncture in chronic pain conditions have been promising, and recent evidence supports the use of abdominal pain in chronic abdominal pain conditions as well. Though not curative, acupuncture is a complementary approach that helps reduce symptoms and improved quality of life. Conclusions: Chronic abdominal pain is a widespread condition, mostly affected by the IBS and IBD spectrum. Etiologies are still being studied for these conditions, and while novel treatment approaches are absolute game changers for these patients, many continue to experience some level of symptoms and disability. Acupuncture may provide further alleviation of these symptoms in select patients, thus improving quality of life, reducing disability, and saving healthcare dollars. It is a largely safe and inexpensive method that may significantly contribute to the quality of life of selected patients. © 2021, Author(s)

Does It Matter Who Writes Medical News Stories?

David Henry and colleagues review Australian news stories over a five-year period to assess whether quality is associated with who wrote the story: a specialist health journalist or a non-specialist

Developing 1D nanostructure arrays for future nanophotonics

There is intense and growing interest in one-dimensional (1-D) nanostructures from the perspective of their synthesis and unique properties, especially with respect to their excellent optical response and an ability to form heterostructures. This review discusses alternative approaches to preparation and organization of such structures, and their potential properties. In particular, molecular-scale printing is highlighted as a method for creating organized pre-cursor structure for locating nanowires, as well as vapor–liquid–solid (VLS) templated growth using nano-channel alumina (NCA), and deposition of 1-D structures with glancing angle deposition (GLAD). As regards novel optical properties, we discuss as an example, finite size photonic crystal cavity structures formed from such nanostructure arrays possessing highQand small mode volume, and being ideal for developing future nanolasers

A Rapid Synthesis of Oriented Palladium Nanoparticles by UV Irradiation

Palladium nanoparticles of average size around 8 nm have been synthesized rapidly by UV irradiation of mixture of palladium chloride and potassium oxalate solutions. A rod-shaped palladium oxalate complex has been observed as an intermediate. In the absence of potassium oxalate, no Pd nanoparticles have been observed. The synthesized Pd nanoparticles have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction and energy dispersive analysis by X-rays (EDAX) analyses. XRD analysis indicates the preferential orientation of catalytically active {111} planes in Pd nanoparticles. A plausible mechanism has been proposed for the formation of anisotropic Pd nanoparticles