A novel topology for a HEMT negative current mirror

A new solution for the implementation of a HEMT negative current source is presented. The topology can be also profitably employed as a current mirror and as an active load in high-gain MMICs voltage amplifiers. A small-signal model of the proposed circuit is developed which allows to find accurate expressions for the required transfer functions (i.e., the output impedance of the current source, and the current gain of the circuit when operated as a current mirror). Design examples using Philips PML ED02AH GaAs PHEMT process are provided. Spice simulations show that a 10- kW output impedance for the current source and a 35dB voltage gain for a differential pair loaded with the proposed current mirror are easily achieved

Calibration of pipeline ADC with pruned Volterra kernels

A Volterra model is used to calibrate a pipeline ADC simulated in Cadence Virtuoso using the STMicroelectronics CMOS 45 nm process. The ADC was designed to work at 50 MSps, but it is simulated at up to 125 MSps, proving that calibration using a Volterra model can significantly increase sampling frequency. Equivalent number of bits (ENOB) improves by 1-2.5 bits (6-15 dB) with 37101 model parameters. The complexity of the calibration algorithm is reduced using different lengths for each Volterra kernels and performing iterative pruning. System identification is performed by least squares techniques with a set of sinusoids at different frequencies spanning the whole Nyquist band. A comparison with simplified Volterra models proposed in the literature shows better performance for the pruned Volterra model with comparable complexity, improving linearity by as much as 1.5 bits more than the other techniques

Housing market trend and rail transport investments in the city of Naples

Rail transport investments can influence housing market trends, as demonstrated in the literature. However many empirical researches highlight that different results can derive from different urban context applications and that each case should be threaten separately. It is for this reason that this paper is focused on the single case of the city of Naples, where many rail transport investments have been carried out in the last decades. The aim of this study is to give an interpretation of the housing values changes due to the opening of new metro stations. This study applies GIS tools in order to show the spatial distribution and the intensity of rail impacts in different areas of the urban system from 1994 to 2004. This study shows that the extent of the impacts varies from place to place and the effects intensity requires the presence of several complementary factors such as central location of the new stations and the presence of urban planning policies in the transit corridors. This again testifies how housing market is strictly related to the infrastructures investments planning and urban design

Feeling like a group after a natural disaster: Common ingroup identity and relations with outgroup victims among majority and minority young children

We conducted a field study to test whether the common ingroup identity model (Gaertner & Dovidio, 2000, reducing intergroup bias: The common ingroup identity model. Philadelphia, PA: Psychology Press) could be a useful tool to improve intergroup relations in the aftermath of a natural disaster. Participants were majority (Italian) and minority (immigrant) elementary school children (N = 517) living in the area struck by powerful earthquakes in May 2012. Results revealed that, among majority children, the perceived external threat represented by the earthquake was associated with greater perceptions of belonging to a common ingroup including both ingroup and outgroup. In turn, heightened one-group perceptions were associated with greater willingness to meet and help outgroup victims, both directly and indirectly via more positive outgroup attitudes. Among immigrant children, perceived disaster threat was not associated with any of the dependent variables; one-group perceptions were positively associated with outgroup attitudes, helping and contact intentions towards outgroup victims. Thus, onegroup perceptions after a natural disaster may promote more positive and supporting relations between the majority and the minority group. We discuss the theoretical and practical implications of the findings

Cancer anorexia: hypothalamic activity and its association with inflammation and appetite-regulating peptides in lung cancer

Background Energy homeostasis is mediated by the hypothalamus, whose inflammation-induced functional derangements contribute to the onset of anorexia in cancer. By using functional magnetic resonance imaging (fMRI), we determined the patterns of hypothalamic activation after oral intake in anorexic (A), non-anorexic (NA) cancer patients, and in controls (C). Methods Lung cancer patients were considered. Hypothalamic activation was recorded in A and NA patients and in C by fMRI, before (T0), immediately after (T1) the administration of an oral nutritional supplement, and after 15 min (T2). The grey of the hypothalamus and Blood Oxygen Level Dependent (BOLD) intensity were calculated and normalized for basal conditions. Interleukin (IL)-1, IL-6, tumour necrosis factor (TNF)-α, ghrelin, and leptin plasma levels were measured. A statistical parametric mapping was used. Results Thirteen lung cancer patients (7 M, 6 F; 9A, 4NA) and 2 C (1 M, 1 F) were enrolled. Controls had the lowest BOLD intensity. At all-time points, anorexic patients showed lower hypothalamic activity compared with NA (P < 0.001) (T0: 585.57 ± 55.69 vs. 667.92 ± 33.18, respectively; T1: 536.50 ± 61.70 vs. 624.49 ± 55.51, respectively; T2: 556.44 ± 58.51 vs. 615.43 ± 71.50, respectively). Anorexic patients showed greater BOLD signal reduction during T0–T1 than NA (8.5% vs. 6.80%, P < 0.001). Independently from the presence of anorexia, BOLD signals modification before and after oral challenge correlated with basal values of IL-1 and ghrelin (P < 0.001). Conclusions Hypothalamic activity in A cancer patients is reduced respect to NA and responds differently to oral challenges. This suggests a central control of appetite dysregulation during cancer anorexia, before, and after oral intake