Retrieval of the ultraviolet aerosol optical depth during a spring campaign in the Bavarian Alps

A measurement campaign was organized in March 1999 in the Bavarian Alps as part of the European project, Characteristics of the UV Radiation Field in the Alps (CUVRA), to analyze the effect of altitude, aerosols, and snow cover on ground-level UV spectral irradiance. We present the results of simultaneous measurements of aerosol optical depth (AOD) made at various sites on two cloudless days in March 1999. The two days exhibited different aerosol conditions. Results derived from spectral measurements of UV irradiance are compared with data from filter radiometer measurements made at discrete wavelengths extending from the UV to the near IR. The different methods generated values for the AOD that were in good agreement. This result confirms that one can use either method to retrieve the AOD with an uncertainty of approximately 0.03-0.05. On 18 March, high turbidity was observed at low altitude (400-nm AOD approximately 0.5 at 700 m above sea level), and the AOD decreased regularly with altitude; on 24 March, the turbidity was much less (0.11 at 700 m above sea level). On both days very low AODs (0.05-0.09) were measured at 3000 m above sea level. The spectral dependence of the AOD is often parameterized by the angstrom relationship; the alpha parameter is generally difficult or impossible to retrieve from spectral measurements because of the relatively narrow wavelength range (320-400 nm), and only one of the spectro-radiometers used during the campaign permits this retrieval. In most cases, during this field campaign, alpha was found by filter sunphotometers to be 1.1-1.5.     

Adaptive IPTV services based on a novel IP Multimedia Subsystem

Heterogeneous communication devices are emerging and changing the way of communication. Innovative multimedia applications are now accessible through these embedded systems. The 3GPP IP Multimedia Subsystem (IMS) provides a basic architecture framework for the Next Generation Network (NGN) supporting the convergence platform for service provisioning in heterogeneous networks. ETSI TISPAN standardization effort focuses on delivering IPTV services on such platform. Nevertheless, IPTV on IMS standardization suffers from a lack of efficient user-centric network management mechanisms as the end-user may consume IPTV service from different access networks, on different mobile devices, at anytime. User’s Perceived Quality of Service (PQoS) or Quality of Experience (QoE) of IPTV service may also suffer from wireless access network impairments. This paper introduces new functionalities in IPTV over IMS architecture which optimize satisfaction of the end-user and resource utilization of the operator’s networks. A context-sensitive User Profile (UP) model is used to deliver IPTV streams adapted to the user’s environment. In order to optimize the operator network usage, the impact of spatiotemporal dynamics of the video content on the deduced perceptual quality is considered. A Multimedia Content Management System (MCMS) is proposed to perform dynamic cross-layer adaptation of the IPTV stream based on PQoS measurements at the end-user side.     

Explicit modelling of the double‐gate MOSFET with VHDL‐AMS

This paper presents a new compact model for the undoped, long‐channel double‐gate (DG) MOSFET under symmetrical operation. In particular, we propose a robust algorithm for computing the mobile charge density as an explicit function of the terminal voltages. It allows to greatly reduce the computation time without losing any accuracy. In order to validate the analytical model, we have also developed the 2D simulations of a DG MOSFET structure and performed both static and dynamic electrical simulations of the device. Comparisons with the 2D numerical simulations give evidence for the good behaviour and the accuracy of the model. Finally, we present the VHDL‐AMS code of the DG MOSFET model and related simulation results. Copyright © 2006 John Wiley & Sons, Ltd.     

Pyramido-lunar fusion in black Africans. Apropos of 32 cases

Lunotriquetral coalition is a congenital carpal anomaly rarely discovered in a white population. In the black population, most cases have concerned blacks in America, Australia and South Africa. In the Sub-Saharia area, in Senegal, the authors, after 8 incidental cases, report 32 lunotriquetral coalitions collected in 20 patients. This retrospective study comparatively analysed 361 X-rays of the wrist performed between February 1989 and July 1992 in the Orthopaedic and Traumatologic Center (CTO) in Dakar. The bony coalition was bilateral in 12 patients and unilateral in the other 8 cases. The complete form (type III) was the most frequent (46.8%). In the bilateral forms, 5 patients presented this complete form. Lunotriquetral coalition was associated, in absence of congenital abnormalities, with a synovial cyst of the wrist (2 cases), scaphoid fracture (1 case), non-union of a scaphoid fracture (1 case) and osteoarthritis of the wrist (2 cases). After review of the literature, the authors discuss racial factors, anatomo-radiographic forms and associated injuries.     

Survey on Wireless Networks Coexistence: Resource Sharing in the 5G Era

Mobile Networks and Applications - The next generation of mobile-enabled wireless networks, known as 5G networks, is announced to be deployed by 2020. In the 5G framework, access technologies are...     

Internet addiction: Meta-synthesis of qualitative research for the decade 1996–2006

Internet addiction is “an individual’s inability to control their Internet use, which in turn leads to feelings of distress and functional impairment of daily activities” [Shapira, N., Lessig, M., Goldsmith, T., Szabo, S., Lazoritz, M., Gold, M. et al. (2003). Problematic Internet use: Proposed classification and diagnostic criteria. Depression and Anxiety, 17(4), 207–216]. Previous research in this field has offered inconclusive data on whether Internet addiction can be classified as a disorder. This study provides an in-depth and comprehensive analysis of internet addiction through a meta-synthesis of qualitative studies on excessive Internet use published during the period of 1996–2006. Several constructs pertaining to the domain of Internet addiction have been identified and a theoretical model of Internet addiction has been proposed.     

Lysophosphatic acid modulates prostaglandin secretion in the bovine uterus

Lysophosphatidic acid (LPA) modulates prostaglandin (PG) synthesis via LPA receptor 3 (LPAR3) in the murine endometrium. The lack of functional LPAR3 in mice may lead to embryo mortality. In the present study, we examined the role of LPA in the bovine uterus. We confirmed that LPA is locally produced and released from the bovine endometrium. Moreover, there are enzymes involved in LPA synthesis (phospholipase (PL) D(2) and PLA2G1B) in the bovine endometrium during estrous cycle and early pregnancy. Expression of the receptor for LPA (LPAR1) was positively correlated with the expression of PGE(2) synthase (PGES) and negatively correlated with the expression of PGF(2alpha) synthase (aldose reductase with 20 alpha-hydroxysteroid dehydrogenase activity - PGFS) during early pregnancy. In vivo LPA induced P4 and PGE(2) secretion was inhibited by LPAR1 antagonist (Ki16425). The overall results indicate that LPA is locally produced and released from the bovine endometrium. Moreover, LPAR1 gene expression in the endometrium during the estrous cycle and early pregnancy indicates that LPA may play autocrine and/or paracrine roles in the bovine uterus. LPAR1 gene expression is positively correlated with the expression of the enzyme responsible for luteotropic PGE(2) production (PGES) in endometrium. In cow, LPA stimulates P4 and PGE(2) secretion. Thus, LPA in the bovine reproductive tract may indirectly (via endometrium) or directly support corpus luteum action via the increase of P4 synthesis and the increase of PGE(2)/PGF(2)(alpha) ratio. It suggests that LPA may serve as an important factor in the maintenance of early pregnancy in cow.     

Coupled effects of sulphate and temperature on the strength development of cemented tailings backfills: Portland cement-paste backfill

Cemented paste backfill (CPB), which is a mix of tailings, water and cement, is subjected to the combined actions of temperature and sulphate during its service life. There is a need to acquire solid knowledge on the coupled effects of temperature and sulphate on the strength of CPBs for a safe, durable and cost-effective design of CPB structures. Hence, the main objective of this paper is to use an experimental approach to study the combined effect of temperature and sulphate on the strength development and microstructure (mineralogical composition of the hardened cement paste) of CPBs. About 200 CPB specimens with various initial sulphate contents (0, 5000, 15,000, and 25,000 ppm) and cured at different temperatures (0 °C, 25 °C, 20 °C, 35 °C, and 50 °C) are tested at different curing times (28, 90, and 150 days). The results show that the coupled effect of temperature and sulphate has a significant impact on the strength and mineralogical composition of the CPB. Depending on the curing time, temperature and initial sulphate content, the sulphate can have a positive or negative impact, i.e., leads to an increase or decrease of CPB strength. The obtained results show a strong indication that the absorption of sulphate by calcium–silicate–hydrate (C–S–H) could lead to the formation of lower quality C–S–H, thereby decreasing the strength of the CPB. This study has demonstrated that the coupled effect of sulphate and temperature on CPBs is an important factor for consideration in the designing of cost-effective, safe and durable CPB structures.     

The impact of NERICA adoption on productivity and poverty of the small-scale rice farmers in the Gambia

The study assessed the causal effects of NERICA adoption on rice yields and income, using country-wide data of 600 rice farmers in The Gambia. To control for differences in socio-demographic and environmental characteristics of adopters and non-adopters and enable a causal interpretation of NERICA adoption on the variables of interest, the study used the counterfactual outcome framework to control for such differences. The results, based on observed sample estimates, showed significant differences in rice yields and income between the NERICA adopters and non-adopters. Further, the results of the framework, based on the Local Average Treatment Effect (LATE) estimates, which allowed a causal interpretation, showed that NERICA adoption significantly increased average rice yields and annual income of small-scale rice farmers by 157 kg per hectare and $148, respectively.     

Testing Parameter Change in General Integer‐Valued Time Series

We consider the structural change in a class of discrete valued time series, which the conditional distribution belongs to the one‐parameter exponential family. We propose a change point test based on the maximum likelihood estimator of the model's parameter. Under the null hypothesis (of no change), the test statistic converges to a well‐known distribution, allowing the calculation of the critical value of the test. The test statistic diverges to infinity under the alternative, meaning that the test has asymptotic power one. Some simulation results and real data applications are reported to show the effectiveness of the proposed procedure.