Wireless Information-Theoretic Security Bloch, M.; Barros, J.; Rodrigues, M.R.D. ...
IEEE transactions on information theory,
06/2008, Letnik:
54, Številka:
6
Journal Article
Recenzirano
This paper considers the transmission of confidential data over wireless channels. Based on an information-theoretic formulation of the problem, in which two legitimates partners communicate over a ...quasi-static fading channel and an eavesdropper observes their transmissions through a second independent quasi-static fading channel, the important role of fading is characterized in terms of average secure communication rates and outage probability. Based on the insights from this analysis, a practical secure communication protocol is developed, which uses a four-step procedure to ensure wireless information-theoretic security: (i) common randomness via opportunistic transmission, (ii) message reconciliation, (iii) common key generation via privacy amplification, and (iv) message protection with a secret key. A reconciliation procedure based on multilevel coding and optimized low-density parity-check (LDPC) codes is introduced, which allows to achieve communication rates close to the fundamental security limits in several relevant instances. Finally, a set of metrics for assessing average secure key generation rates is established, and it is shown that the protocol is effective in secure key renewal-even in the presence of imperfect channel state information.
Abstract
Background
Multimorbidity is defined as the presence of multiple chronic conditions in the same individual. Multimorbidity is more prevalent in older adults and can lead to several adverse ...health outcomes.
Methods
We systematically reviewed evidence from observational studies to verify the association between multimorbidity and hospitalization in older adults. Furthermore, we also aimed to identify whether it changes according to gender, advanced age, institutionalization, and wealth of the country of residence. We searched the PubMed, Embase and Scopus databases from December 2020 to April 2021. The analysed outcomes were as follows: hospitalization, length of stay and hospital readmission.
Results
Of the 6,948 studies identified in the databases, 33 were included in this review. From the meta-analysis results, it was found that multimorbidity, regardless of the country’s wealth, was linked to hospitalization in older adults (OR = 2.52, CI 95% = 1.87–3.38). Both definitions of multimorbidity, ≥2 (OR = 2.35, 95% CI = 1.34–4.12) and ≥3 morbidities (OR = 2.52, 95% CI = 1.87–3.38), were associated with hospitalization. Regardless of gender, multimorbidity was associated with hospitalization (OR = 1.98, 95% CI = 1.67–2.34) and with readmission (OR = 1.07, 95% CI = 1.04–1.09). However, it was not possible to verify the association between multimorbidity and length of stay.
Conclusions
Multimorbidity was linked to a higher hospitalization risk, and this risk was not affected by the country’s wealth and patient’s gender. Multimorbidity was also linked to a higher hospital readmission rate in older adults. PROSPERO Registration (Registration number: CRD42021229328).
In this paper, we develop a framework to design sensing matrices for compressive sensing applications that lead to good mean squared error (MSE) performance subject to sensing cost constraints. By ...capitalizing on the MSE of the oracle estimator, whose performance has been shown to act as a benchmark to the performance of standard sparse recovery algorithms, we use the fact that a Parseval tight frame is the closest design - in the Frobenius norm sense - to the solution of a convex relaxation of the optimization problem that relates to the minimization of the MSE of the oracleestimator with respect to the equivalent sensing matrix, subject to sensing energy constraints. Based on this result, we then propose two sensing matrix designs that exhibit two key properties: the designs are closed form rather than iterative; the designs exhibit superior performance in relation to other designs in the literature, which is revealed by our numerical investigation in various scenarios with different sparse recovery algorithms including basis pursuit de-noise (BPDN), the Dantzig selector and orthogonal matching pursuit (OMP).
A number of novel, water-stable redox-active cobalt complexes of the C-functionalized tripodal ligands tris(pyrazolyl)methane XC(pz)(3) (X = HOCH(2), CH(2)OCH(2)Py or CH(2)OSO(2)Me) are reported ...along with their effects on DNA. The compounds were isolated as air-stable solids and fully characterized by IR and FIR spectroscopies, ESI-MS(+/-), cyclic voltammetry, controlled potential electrolysis, elemental analysis and, in a number of cases, also by single-crystal X-ray diffraction. They showed moderate cytotoxicity in vitro towards HCT116 colorectal carcinoma and HepG2 hepatocellular carcinoma human cancer cell lines. This viability loss is correlated with an increase of tumour cell lines apoptosis. Reactivity studies with biomolecules, such as reducing agents, H(2)O(2), plasmid DNA and UV-visible titrations were also performed to provide tentative insights into the mode of action of the complexes. Incubation of Co(II) complexes with pDNA induced double strand breaks, without requiring the presence of any activator. This pDNA cleavage appears to be mediated by O-centred radical species.
We predict a mechanism to controllably manipulate domain walls in kagome antiferromagnets via a single linearly polarized spin-wave source. We show by means of atomistic spin dynamics simulations of ...antiferromagnets with kagome structure that the speed and direction of the domain wall motion can be regulated by only tuning the frequency of the applied spin wave. Starting from microscopics, we establish an effective action and derive the corresponding equations of motion for the spin-wave-driven domain wall. Our analytical calculations reveal that the coupling of two spin-wave modes inside the domain wall explains the frequency-dependent velocity of the spin texture. Such a highly tunable spin-wave-induced domain wall motion provides a key component toward next-generation fast, energy-efficient, and Joule-heating-free antiferromagnetic insulator devices.
Phylogenetic analysis has demonstrated that the etiologic agent of the 2020 pandemic outbreak is a betacoronavirus named SARS-CoV-2. For public health interventions, a diagnostic test with high ...sensitivity and specificity is required. The gold standard protocol for diagnosis by the Word Health Organization (WHO) is RT-PCR. To detect low viral loads and perform large-scale screening, a low-cost diagnostic test is necessary. Here, we developed a cost-effective test capable of detecting SARS-CoV-2. We validated an auxiliary protocol for molecular diagnosis with the SYBR Green RT-PCR methodology to successfully screen negative cases of SARS-CoV-2. Our results revealed a set of primers with high specificity and no homology with other viruses from the Coronovideae family or human respiratory tract pathogenic viruses, presenting with complementarity only for rhinoviruses/enteroviruses and Legionella spp. Optimization of the annealing temperature and polymerization time led to a high specificity in the PCR products. We have developed a more affordable and swift methodology for negative SARS-CoV-2 screening. This methodology can be applied on a large scale to soften panic and economic burden through guidance for isolation strategies.
This study aims to evaluate the effects of adding alpha lipoic acid (ALA) to the in vitro ovarian tissue culture medium, either fresh or after vitrification/warming. For this purpose, 10 ovaries from ...five adult sheep were used. Each pair of ovaries gave rise to 16 fragments and were randomly distributed into two groups: fresh (n = 8) and vitrified (n = 8). Two fresh fragments were fixed immediately and considered the control, while another six were cultured in vitro for 14 days in the absence; presence of a constant (100 μM/0–14 day) or dynamic (50 μM/day 0–7 and 100 μM/day 8–14) concentration of ALA. As for the vitrified fragments, two were fixed and the other six were cultured in vitro under the same conditions described for the fresh group. All the fragments were subjected to morphological evaluation, follicular development and stromal density (classical histology), DNA fragmentation (TUNEL), senescence (Sudan Black), fibrosis (Masson's Trichome), and endoplasmic reticulum stress (immunofluorescence). Measurements of the antioxidant capacity against the free radicals 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and estradiol (E2) levels in the culture medium was performed. The results showed that in the absence of ALA, in vitro culture of vitrified ovarian fragments showed a significant reduction (P < 0.05) in follicular morphology and increased the presence of senescence and tissue fibrosis (P < 0.05). Dynamic ALA maintained E2 levels unchanged (P > 0.05) until the end of vitrified ovarian tissue culture and controlled the levels of ABTS and DPPH radicals in fresh or vitrified cultures. Therefore, it is concluded that ALA should be added to the vitrified ovarian tissue in vitro culture medium to reduce the damage that leads to loss of ovarian function. To ensure steroidogenesis during in vitro culture, ALA should be added dynamically (different concentrations throughout culture).
•Addition of ALA to vitrified ovary in vitro culture medium reduces fibrosis and cellular senescence.•In vitro culture of vitrified ovary to restore endocrine function.•Conservation of ovarian follicles in situ.
Background
Nonpharmacological labor pain management methods (NPLPMM) are noninvasive, low‐cost practices that may play a role in reducing the rates of unnecessary cesarean birth. We aimed to evaluate ...whether the NPLPMM is associated with the mode of birth.
Methods
We conducted a retrospective cohort study with clinical records of all women admitted for birth from January 2013 to December 2017. Records of women who had spontaneous labor or received induction or augmentation of labor during hospitalization were eligible for the study. We estimated the risk ratios for cesarean birth in general linear models using the Poisson regression with adjustments for the following variables: age, ethnicity, schooling, parity, gestational age, previous cesarean birth, spontaneous labor before admission, or induction/augmentation of labor.
Results
Within the total of 3,391 medical records, 40.1% had the use of a nonpharmacological labor pain management method registered. Cesarean rate among the study population was 44.2%. The use of NPLPMM decreased the risk of cesarean birth by 78% (OR = 0.22; 95% CI 0.19‐0.26). History of a previous cesarean birth (RR = 2.63; 95% CI 2.35‐2.64), the lack of use of NPLPMM (RR = 2.46; 95% CI 2.22‐2.72), and primiparity (RR = 2.09; 95% CI 1.86‐2.34) were the strongest risk factors for cesarean birth in the cohort.
Discussion
The use of NPLPMM may be an effective strategy to reduce unnecessary cesarean birth. Further studies to identify the efficacy of each method may help health professionals to offer more appropriate methods at different stages of labor.
Clustering in low density nuclear matter has been investigated using the NIMROD multidetector at Texas A&M University. Thermal coalescence modes were employed to extract densities, ρ, and ...temperatures, T, for evolving systems formed in collisions of 47A MeV (40)Ar+(112)Sn, (124)Sn and (64)Zn+(112)Sn, (124)Sn. The yields of d, t, (3)He, and (4)He have been determined at ρ=0.002 to 0.03 nucleons/fm(3) and T=5 to 11 MeV. The experimentally derived equilibrium constants for α particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.
Display omitted
▶ Antimicrobial and anti-adhesive properties of a biosurfactant Rufisan were determined. ▶ Rufisan was isolated from the yeast Candida lipolytica UCP 0988. ▶ Rufisan is a potential ...antimicrobial and anti-adhesive agent for biomedical applications.
In the last years, researches developed with biosurfactants for application in the medical area have been revealing the promising biological activities of these biomolecules. In this work the antimicrobial and anti-adhesive properties of a biosurfactant Rufisan isolated from the yeast Candida lipolytica UCP 0988, growth in a medium supplemented with ground nut refinery residue was determined against several microorganisms. The biosurfactant was able to reduce the water surface tension from 70 to 25.3mN/m and showed a critical micelle concentration (CMC) of 0.03%. The biosurfactant was isolated after 72h of fermentation and was tested in concentrations varying from 0.75 to 12mg/l. The highest antimicrobial activities were observed against Streptococcus agalactiae, Streptococcus mutans, Streptococcus mutans NS, Streptococcus mutans HG, Streptococcus sanguis 12, Streptococcus oralis J22 at a concentration superior to the biosurfactant critical micelle concentration. Moreover, the biosurfactant showed anti-adhesive activity against most of the microorganisms tested. As far as we know, this is the first compilation of data on antimicrobial and anti-adhesive activities of a biosurfactant obtained from a Candida strain against such a broad group of microorganisms. The results obtained in this work showed that the biosurfactant from C. lipolytica is a potential antimicrobial and/or anti-adhesive agent for several biomedical applications.
PDF
