Search results for " multiple"
showing 10 items of 903 documents
Moving RTS/CTS to the frequency domain: an efficient contention scheme for 802.11ax networks
2019
In this paper, we propose a contention mechanism based on the execution of multiple contention rounds in the frequency domain (ReCHo), which is designed to offer high throughput performance and robustness with respect to imperfect carrier sensing. The main idea is using narrow tones as signalling messages for performing channel access contentions and allowing the Access Point (AP) to echo these signals, in order to extend the sensing capabilities to all the stations associated to the AP. In particular, we refer to the emerging IEEE 802.11ax standard, showing how our scheme can boost performance of random access with respect to the current version of IEEE 802.11ax OFDMA Back-Off (OBO), even …
'Good to Repeat': Making Random Access Near-Optimal with Repeated Contentions
2020
Recent advances on WLAN technology have been focused mostly on boosting network capacity by means of a more efficient and flexible physical layer. A new concept is required at MAC level to exploit fully the new capabilities of the PHY layer. In this article, we propose a contention mechanism based on Repeated Contentions (ReCo) in frequency domain. It provides a simple-to-configure, robust and short-term fair algorithm for the random contention component of the MAC protocol. The throughput efficiency of ReCo is not sensitive to the number of contending stations, so that ReCo does not require adaptive tuning of the access parameters for performance optimization. Efficiency and robustness is …
An Internet-delivered Cognitive-Behavioral Therapy (iCBT) for Prolonged Grief Disorder (PGD) in adults: A multiple-baseline single-case experimental …
2022
The death of a loved one has physical, psychological, and social consequences. Between 9.8 and 21.5 % of people who lose a loved one develop Prolonged Grief Disorder (PGD). Internet- and computer-based interventions (i.e., Internet-delivered Cognitive-Behavioral Therapy, iCBT) are cost-effective and scalable alternatives that make it possible to reach more people with PGD. The main goal of the present investigation was to examine the effect and feasibility (usability and satisfaction) of an iCBT (GROw program) for adults with PGD. A secondary objective was to detect adherence to the app (Emotional Monitor) used to measure daily grief symptoms. The study had a singlecase multiple-baseline AB…
Environmental context determines pollution impacts on ecosystem functioning
2023
Global change assessments have typically ignored synthetic chemical pollution, despite the rapid increase of pharmaceuticals, pesticides and industrial chemicals in the environment. Part of the problem reflects the multifarious origins of these micropollutants, which can derive from urban and agricultural sources. Understanding how micropollutants harm ecosystems is a major scientific challenge due to asymmetries of stress across trophic levels and ecological surprises generated by multiple drivers interacting in human-impacted landscapes. We used field assays above and below municipal wastewater treatment plants (WWTPs) in 60 sampling locations across 20 Swiss streams to test how micropoll…
Cognition in Interaction : Challenges in Assessing Persons with Sensory and Multiple disabilities
2021
This article reports a qualitative study of cognitive assessments of three teenagers with sensory and multiple disabilities, including moderate to profound developmental disability. The aim was to evaluate the possibilities for adapting standardized tests and the implementation of interactional partnership in assessment. Cognitive assessments were made with an individually-adapted psychological assessment tool, the Bayley Scales of Infant and Toddler Development. The assessment situations were video-recorded and analyzed based on sociocultural theories of early interaction, dynamic assessment, and the bodily-tactile modality of cognition. The results showed that the requirements for assessm…
Progenitor death drives retinal dysplasia and neuronal degeneration in a mouse model of Atrip-Seckel syndrome
2020
ABSTRACT Seckel syndrome is a type of microcephalic primordial dwarfism (MPD) that is characterized by growth retardation and neurodevelopmental defects, including reports of retinopathy. Mutations in key mediators of the replication stress response, the mutually dependent partners ATR and ATRIP, are among the known causes of Seckel syndrome. However, it remains unclear how their deficiency disrupts the development and function of the central nervous system (CNS). Here, we investigated the cellular and molecular consequences of ATRIP deficiency in different cell populations of the developing murine neural retina. We discovered that conditional inactivation of Atrip in photoreceptor neurons …
Perlman syndrome: Clinical report and nine-year follow-up
2005
We present the clinical and follow-up data of a female infant with Perlman syndrome from birth to the age of 9 years. Main features of Perlman syndrome include polyhydramnios, fetal overgrowth, neonatal macrosomia, macrocephaly, dysmorphic facial features, visceromegaly, nephroblastomatosis, and a predisposition for Wilm's tumor. In our patient, the nephromegaly with nephroblastomatosis was not present at birth or during the neonatal period; it became evident in the first months of postnatal life. A Wilm's tumor was diagnosed when she was about 1 year old. Long term follow-up documents the natural history of Perlman syndrome and allows us to establish the long-term prognosis of the affected…
High-precision mass measurements for the isobaric multiplet mass equation atA= 52
2017
Masses of $^{52}$Co, $^{52}$Co$^m$, $^{52}$Fe, $^{52}$Fe$^m$, and $^{52}$Mn have been measured with the JYFLTRAP double Penning trap mass spectrometer. Of these, $^{52}$Co and $^{52}$Co$^m$ have been experimentally determined for the first time and found to be more bound than predicted by extrapolations. The isobaric multiplet mass equation for the $T=2$ quintet at $A=52$ has been studied employing the new mass values. No significant breakdown (beyond the $3\sigma$ level) of the quadratic form of the IMME was observed ($\chi^2/n=2.4$). The cubic coefficient was 6.0(32) keV ($\chi^2/n=1.1$). The excitation energies for the isomer and the $T=2$ isobaric analogue state in $^{52}$Co have been d…
Mass of astrophysically relevant 31Cl and the breakdown of the isobaric multiplet mass equation
2015
The mass of $^{31}$Cl has been measured with the JYFLTRAP double Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, -7034.7(34) keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the T=3/2 quartet at A=31 fails ($\chi^2_n$=11.6) and a non-zero cubic term, d=-3.5(11) keV, is obtained when the new mass value is adopted. $^{31}$Cl has been found to be less proton-bound with a proton separation energy of $S_p$=265(4) keV. Energies for the excited states in $^{31}$Cl and the photodisintegration rate on $^{31}$Cl have been determined with s…
Autosomal recessive severe dwarfism in a Sicilian girl: a new form of osteodysplastic primordial dwarfism?
1996
A new type of osteodysplastic primordial dwarfism is delineated in a 5- year-old female child with severe growth retardation of prenatal onset, gross skeletal changes, a non-Seckel facial phenotype, and presumed autosomal recessive inheritance.