220 research outputs found
Paramagnon Heat Capacity and Anomalous Thermopower in Anisotropic Magnetic Systems: Understanding Inter-Layer Spin Correlations in a Magnetically Disordered Phase
The interplay between entropy transport and charge carriers-paramagnon
interaction in the Onsager linear system has been a subject of debate due to
the limited theoretical and experimental understanding of paramagnon heat
capacity. In this study, we investigate this interplay in an anisotropic
layered magnetic system using cluster mean-field theory with spin quantum
correlations. By examining spin correlation functions between different spins
with various types of clustering, we derive the spin correlation function as a
function of distance and temperature for the inter-layer clusters both below
and above the magnetic order phase transition. Our analysis reveals that
paramagnons characterized by pronounced spin correlations among inter-layer
nearest-neighbor spins exhibit a non-zero heat capacity, providing valuable
insights into the dynamics of entropy transport. The findings align with
experimental observations, lending strong support to the validity of the
paramagnon drag thermopower concept. This study sheds light on the intricate
dynamics and thermodynamic properties of paramagnons, advancing our
understanding of entropy transport in complex systems.Comment: 8 pages, 7 figure
Peeking Inside the Schufa Blackbox: Explaining the German Housing Scoring System
Explainable Artificial Intelligence is a concept aimed at making complex
algorithms transparent to users through a uniform solution. Researchers have
highlighted the importance of integrating domain specific contexts to develop
explanations tailored to end users. In this study, we focus on the Schufa
housing scoring system in Germany and investigate how users information needs
and expectations for explanations vary based on their roles. Using the
speculative design approach, we asked business information students to imagine
user interfaces that provide housing credit score explanations from the
perspectives of both tenants and landlords. Our preliminary findings suggest
that although there are general needs that apply to all users, there are also
conflicting needs that depend on the practical realities of their roles and how
credit scores affect them. We contribute to Human centered XAI research by
proposing future research directions that examine users explanatory needs
considering their roles and agencies.Comment: 7 pages, 3 figures, ACM CHI 2023 Workshop on Human-Centered
Explainable AI (HCXAI
PAMAM dendrimer roles in gene delivery methods and stem cell research
Nanotechnology has provided new technological opportunities, which could help in challenges confronting stem cell research. Polyamidoamine (PAMAM) dendrimers, a new class of macromolecular polymers with high molecular uniformity, narrow molecular distribution specific size and shape and highly functionalised terminal surface have been extensively explored for biomedical application. PAMAM dendrimers are also nanospherical, hyperbranched and monodispersive molecules exhibiting exclusive properties which make them potential carriers for drug and gene delivery
TOPSIS for solving multi-objective multi-product supplier selection problem under price breaks
Supplier selection is a multi-criteria decision-making problem (MCDM) that is affected by quantitative and qualitative (conflicting) factors. For supplier selection problem, if suppliers offer quantity discounts and buyer wants to buy multiple products as well, this problem becomes more complicated. To solve the problem, an integration of technique for order preference by similarity to ideal solution (TOPSIS) and multi-product multi-objective mixed integer linear programming (MOMILP) is used to consider both tangible and intangible factors in choosing the best suppliers and define the optimum quantities among the selected suppliers. The problem includes the three objective functions: to maximize the total value of purchasing (TVP), and to minimize the total defect rate and total cost, while satisfying demand requirement and capacity constraints. In this paper, to solve the multi-objective model, TOPSIS and later a single objective function are proposed which can consider the relative importance of the three goals
Early chest tube removal after coronary artery bypass graft surgery
Abstract Background: There is no clear data about the optimum time for chest tube removal after coronary artery bypass surgery. Aim: The aim of this study was to assess the impact of the chest tube removal time following coronary artery bypass grafting surgery on the clinical outcome of the patients. Material and Methods: An analysis of data from 307 patients was performed. The patients were randomized into two groups: in group 1 (N=107) chest tubes were removed within the first 24 hours after surgery, whereas in group 2 (N=200), chest tubes were removed in the second 24 hours after surgery. Demographics, lactate and pH at the beginning, during and after the operation, creatinine, left ventricular ejection fraction, inotropic drugs administration, length of ICU stay, and mortality data were collected. Respiratory rate and pain level was assessed. Results: In these surgeries, the mean± standard deviation for the aortic clamping time was 49.18±17.59 minutes and cardiopulmonary bypass time was 78.39±25.12 minutes. The amount of heparin consumed by the second group was higher (P <0.001) which could be considered as an important factor in increasing the drainage time after the surgery (P =0.047). The pain level evaluated 24 hours post-operation was lower in the first group, and the difference in the pain level between the 2 groups evaluated 30 hours post-operation was significant (P=0.016). The mean time of intensive care unit stay was longer in the second group but it was not statistically significant. Conclusion: Early extracting of chest tubes after coronary artery bypass graft surgery when there is no significant drainage can lead to pain reduction and consuming oxygen is an effective measure after surgery toward healing; it doesn't increase the risk of creation of plural effusion and pericardial effusion
Electrical Stimulation Modulates High γ Activity and Human Memory Performance.
Direct electrical stimulation of the brain has emerged as a powerful treatment for multiple neurological diseases, and as a potential technique to enhance human cognition. Despite its application in a range of brain disorders, it remains unclear how stimulation of discrete brain areas affects memory performance and the underlying electrophysiological activities. Here, we investigated the effect of direct electrical stimulation in four brain regions known to support declarative memory: hippocampus (HP), parahippocampal region (PH) neocortex, prefrontal cortex (PF), and lateral temporal cortex (TC). Intracranial EEG recordings with stimulation were collected from 22 patients during performance of verbal memory tasks. We found that high γ (62-118 Hz) activity induced by word presentation was modulated by electrical stimulation. This modulatory effect was greatest for trials with poor memory encoding. The high γ modulation correlated with the behavioral effect of stimulation in a given brain region: it was negative, i.e., the induced high γ activity was decreased, in the regions where stimulation decreased memory performance, and positive in the lateral TC where memory enhancement was observed. Our results suggest that the effect of electrical stimulation on high γ activity induced by word presentation may be a useful biomarker for mapping memory networks and guiding therapeutic brain stimulation
Reactivity of aminophenols in forming nitrogen-containing brown carbon from iron-catalyzed reactions
Nitrogen-containing organic carbon (NOC) in atmospheric particles is an important class of brown carbon (BrC). Redox active NOC like aminophenols received little attention in their ability to form BrC. Here we show that iron can catalyze dark oxidative oligomerization of o- and p-aminophenols under simulated aerosol and cloud conditions (pH 1–7, and ionic strength 0.01–1 M). Homogeneous aqueous phase reactions were conducted using soluble Fe(III), where particle growth/agglomeration were monitored using dynamic light scattering. Mass yield experiments of insoluble soot-like dark brown to black particles were as high as 40%. Hygroscopicity growth factors (κ) of these insoluble products under sub- and super-saturated conditions ranged from 0.4–0.6, higher than that of levoglucosan, a prominent proxy for biomass burning organic aerosol (BBOA). Soluble products analyzed using chromatography and mass spectrometry revealed the formation of ring coupling products of o- and p-aminophenols and their primary oxidation products. Heterogeneous reactions of aminophenol were also conducted using Arizona Test Dust (AZTD) under simulated aging conditions, and showed clear changes to optical properties, morphology, mixing state, and chemical composition. These results highlight the important role of iron redox chemistry in BrC formation under atmospherically relevant conditions
A special discount strategy for supplier selection and order allocation
In this paper, we consider a special discount where: (1) the price breaks depend on the size of the order quantities, (2) independent products' sales volume affect the prices and discounts of the other products and (3) all products must be sold as a bundle. In this circumstance, which the buyer wants to buy multi-product and suppliers also offer the special discount, the problem becomes more complicated. To formulate the problem, multi-objective mixed integer linear programming (MOMILP) is used to define the optimum quantities among the selected suppliers. The problem includes the three objective functions: to minimize the inverse Total Value of Purchasing (TVP), the total cost and total defect rate, while satisfying capacity and demand requirement constraints. In order to solve the model, a single objective function is used that considers relative importance of the goals. A numerical example is given to illustrate how the multi-objective model is applied
Portable, Battery-Operated, Low-Cost, Bright Field and Fluorescence Microscope
This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 µm at 1000× magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted smears were prepared from sputa obtained from 19 patients suspected to have M. tuberculosis infection. Slides were stained with auramine orange and evaluated as being positive or negative for M. tuberculosis with both the new portable fluorescence microscope and a laboratory grade fluorescence microscope. Concordant results were obtained in 98.4% of cases. This highly portable, low cost, fluorescence microscope may be a useful diagnostic tool to expand the availability of M. tuberculosis testing at the point-of-care in low resource settings
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