143 research outputs found
Analysis of the effect of mobile terminal speed on WLAN/3G vertical handovers
Proceedings of IEEE Global Telecommunications Conference, GLOBECOM '06, San Francisco, California, 27 november - 1 december, 2006.WLAN hot-spots are becoming widely spread. This, combined with the availability of new multi-mode terminals integrating heterogeneous technologies, opens new business opportunities for mobile operators. Scenarios in which 3G coverage is complemented by WLAN deployments are becoming available. Thus, true all-IP based networks are ready to offer a new variety
of services across heterogeneous access. However, to achieve this, some aspects still need to be analyzed. In particular, the effect of the terminal speed on the detection and selection process of the preferred access network is not yet well understood. In
fact, efficiency of vertical handovers depends on the appropriate configuration of mobile devices. In this paper we present a
simulation study of handover performance between 3G and WLAN access networks showing the impact of mobile usersâ speed. The mobile devices are based on the IEEE 802.21 cross
layer architecture and use WLAN signal level thresholds as handover criteria. A novel algorithm to dynamically adjust terminalsâ configuration is presented.Publicad
IP Flow Mobility in PMIPv6 Based Networks: Solution Design and Experimental Evaluation
The ability of offloading selected IP data traffic from 3G to WLAN access networks is considered a key feature in the upcoming 3GPP specifications, being the main goal to alleviate data congestion in cellular networks while delivering a positive user experience. Lately, the 3GPP has adopted solutions that enable mobility of IP-based wireless devices relocating mobility functions from the terminal to the network. To this end, the IETF has standardized Proxy Mobile IPv6 (PMIPv6), a protocol capable to hide often complex mobility procedures from the mobile devices. This paper, in line with the mentioned offload requirement, further extends PMIPv6 to support dynamic IP flow mobility management across access wireless networks according to operator policies. Considering energy consumption as a critical aspect for hand-held devices and smart-phones, we assess the feasibility of the proposed solution and provide an experimental analysis showing the cost (in terms of energy consumption) of simultaneous packet transmission/reception using multiple network interfaces. The end-to-end system design has been implemented and validated by means of an experimental network setup.European CommunityÂŽs Seventh Framework ProgramPublicad
Clima organizacional y sĂndrome de burnout en personal de una InstituciĂłn Policial, Arequipa, 2020
El estudio tuvo como finalidad determinar la relaciĂłn entre clima organizacional
y sĂndrome de burnout en una instituciĂłn policial de Arequipa. La muestra se
conformĂł por 240 policĂas, para lo cual el tipo de investigaciĂłn fue de tipo
aplicada correlacional y de diseño no experimental de corte transversal. Los
instrumentos empleados fueron; el Cuestionario de Clima Organizacional y el
Inventario de SĂndrome de Burnout. Los resultados evidencian que el clima
organizacional se correlaciona de manera negativa y dĂ©bil con el sĂndrome de
burnout
The millimetre variability of M81* -- Multi-epoch dual frequency mm-observations of the nucleus of M81
There are still many open questions as to the physical mechanisms at work in
Low Luminosity AGN that accrete in the extreme sub-Eddington regime.
Simultaneous multi-wavelength studies have been very successful in constraining
the properties of SgrA*, the extremely sub-Eddington black hole at the centre
of our Milky Way. M81*, the nucleus of the nearby spiral galaxy M81, is an
ideal source to extend the insights obtained on SgrA* toward higher luminosity
AGN. Here we present observations at 3 and 1 mm that were obtained within the
framework of a coordinated,multi-wavelength campaign on M81*. The continuum
emission from M81* was observed during three epochs with the IRAM Plateau de
Bure Interferometer simultaneously at wavelengths of 3 and 1 mm. We present the
first flux measurements of M81* at wavelengths around 1 mm. We find that M81*
is a continuously variable source with the higher variability observed at the
shorter wavelength. Also, the variability at 3 and 1 mm appears to be
correlated. Like SgrA*, M81* appears to display the strongest flux density and
variability in the mm-to-submm regime. There remains still some ambiguity
concerning the exact location of the turnover frequency from optically thick to
optically thin emission. The observed variability time scales point to an upper
size limit of the emitting region of the order 25 Schwarzschild radii. The data
show that M81* is indeed a system with very similar physical properties to
SgrA* and an ideal bridge toward high luminosity AGN. The data obtained clearly
demonstrate the usefulness and, above all, the necessity of simultaneous
multi-wavelength observations of LLAGN.Comment: accepted for publication in A&
The relation between mortality from malignant melanoma and early detection in the Cancer Research Campaign Mole Watcher Study
Between 1987 and 1989 the Cancer Research Campaign funded a health education programme for the early detection of cutaneous malignant melanoma in the general population in 6 health districts of England and 1 health board in Scotland (population of 3 million). The intervention was evaluated by studying its effects on annual and cumulative mortality rates for melanoma. Population-based data on mortality from melanoma were collected in the intervention areas, the health regions covering those areas, and 5 other health regions of England from 1981 to 1996. Deaths from melanoma in cases diagnosed after the start of the intervention were used to study cumulative mortality rates. The annual mortality rates for melanoma, 1981 to 1996, showed no significant difference in their trends between the intervention areas, and other areas of England and Wales. After adjustment for pre-intervention rates, there was also no significant reduction in cumulative mortality from melanoma in the intervention areas compared with the non-intervention areas: rate ratio 1.2 (95% Cl 0.9â1.7) in men, 0.9 (95% Cl 0.7â1.3) in females. The lack of a significant reduction in melanoma mortality associated with the intervention raises questions about this approach to early detection and emphasises the need for new strategies. © 2001 Cancer Research Campaignhttp://www.bjcancer.co
The Supermassive Black Hole at the Galactic Center
The inner few parsecs at the Galactic Center have come under intense scrutiny
in recent years, in part due to the exciting broad-band observations of this
region, but also because of the growing interest from theorists motivated to
study the physics of black hole accretion, magnetized gas dynamics and unusual
star formation. The Galactic Center is now known to contain arguably the most
compelling supermassive black hole candidate, weighing in at a little over 2.6
million suns. Its interaction with the nearby environment, comprised of
clusters of evolved and young stars, a molecular dusty ring, ionized gas
streamers, diffuse hot gas, and a hypernova remnant, is providing a wealth of
accretion phenomenology and high-energy processes for detailed modeling. In
this review, we summarize the latest observational results, and focus on the
physical interpretation of the most intriguing object in this region---the
compact radio source Sgr A*, thought to be the radiative manifestation of the
supermassive black hole.Comment: Annual Review of Astronomy & Astrophysics, Vol. 39 (2001), in press,
48 pages, 20 figures (partially in reduced quality), also available at
http://www.mpifr-bonn.mpg.de/staff/hfalcke/publications.html#gcrevie
A phase I pharmacokinetics trial comparing PF-05280586 (a potential biosimilar) and rituximab in patients with active rheumatoid arthritis
Aims: Pharmacokinetic (PK) similarity was assessed among PFâ05280586 (a proposed biosimilar) vs. rituximab sourced from the European Union (rituximabâEU) and the United States (rituximabâUS). Pharmacodynamics (PD), overall safety and immunogenicity were also evaluated.
Methods: Patients with active rheumatoid arthritis on a background of methotrexate and inadequate response to one or more tumour necrosis factor antagonist therapies were randomized to intravenous PFâ05280586, rituximabâEU or rituximabâUS 1000 mg doses on study days 1 and 15.
Results: A total of 220 patients were randomized to receive study treatment as assigned. Of these, 198 met perâprotocol population criteria for inclusion in the PK data analysis. PFâ05280586, rituximabâEU and rituximabâUS exhibited similar PK profiles following administration of assigned study drug on days 1 and 15. The 90% confidence intervals of testâtoâreference ratios for Cmax, AUCT, AUC0ââ and AUC2âweek were within the bioequivalence margin of 80.00â125.00% for comparisons of PFâ05280586 with rituximabâEU, PFâ05280586 with rituximabâUS, and rituximabâEU with rituximabâUS. All treatments resulted in a rapid and profound reduction in CD19+ B cells and sustained profound B cell suppression up to week 25. The incidence of antidrug antibody (ADA) response (n = 7, 10 and 9 for PFâ05280586, rituximabâEU and rituximabâUS, respectively), time to ADA emergence and ADA titres were similar across treatments. None of the ADAâpositive samples was positive for neutralizing activity. No clinically meaningful differences in adverse events were identified.
Conclusions: The study demonstrated PK similarity among PFâ05280586, rituximabâEU and rituximabâUS. In addition, all treatments showed comparable CD19+ B cell depletion PD responses, as well as safety and immunogenicity profiles
Quantum chemical calculations of tryptophanâheme electron and excitation energy transfer rates in myoglobin
The development of optical multidimensional spectroscopic techniques has opened up new possibilities for the study of biological processes. Recently, ultrafast two- dimensional ultraviolet spectroscopy experiments have determined the rates of tryptophanâheme electron transfer and excitation energy transfer for the two tryptophan residues in myoglobin [Consani et al., Science, 2013, 339, 1586]. Here we show that accurate prediction of these rates can be achieved using Marcus theory in conjunction with time-dependent density functional theory (TDDFT). Key intermediate residues between the donor and acceptor are identified, and in particular the residues Val68 and Ile75 play a critical role in calculations of the electron coupling matrix elements. Our calculations demonstrate how small changes in structure can have a large effect on the rates, and show that the different rates of electron transfer are dictated by the distance between the heme and tryptophan residues, while for excitation energy transfer the orientation of the tryptophan residues relative to the heme is important
Safety and efficacy of ribociclib plus letrozole in patients with HR+, HER2â advanced breast cancer: Results from the Spanish sub-population of the phase 3b CompLEEment-1 trial
Background: Breast cancer is the most common malignancy and the second leading cause of cancer-related mortality in Spanish women. Ribociclib in combination with endocrine therapy (ET) has shown superiority in prolonging survival in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) vs. ET alone.Methods: CompLEEment-1 is a single-arm, open-label phase 3b trial evaluating ribociclib plus letrozole in a broad population of patients with HR+, HER2- ABC. The primary endpoints were safety and tolerability. Here we report data for Spanish patients enrolled in CompLEEment-1.Results: A total of 526 patients were evaluated (median follow-up: 26.97 months). Baseline characteristics showed a diverse population with a median age of 54 years. At study entry, 56.5% of patients had visceral metastases and 8.7% had received prior chemotherapy for advanced disease. Rates of all-grade and Grade >= 3 adverse events (AEs) were 99.0% and 76.2%, respectively; 21.3% of patients experienced a serious AE, and 15.8% of AEs led to treatment discontinuation. AEs of special interest of neutropenia, increased alanine aminotransferase, increased aspartate aminotransferase and QTcF prolongation occurred in 77.8%, 14.8%, 11.4% and 4.0% of patients, respectively. Patients aged >70 years experienced increased rates of all-grade and Grade >= 3 neutropenia and anemia. Efficacy results were consistent with the global study.Conclusions: Results from Spanish patients enrolled in CompLEEment-1 are consistent with global data showing efficacy and a manageable safety profile for ribociclib plus letrozole treatment in patients with HR+, HER2-ABC, including populations of interest (NCT02941926).Trial registration: ClinicalTrials.gov NCT0294192
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