This brief presents a comprehensive study on a particular kind of conveyor called second-generation voltage conveyor (VCII). This building block is based on voltage conveying concept and is the dual ...of second generation current conveyor (CCII). It is shown that VCII is a very useful block in those configurations where CCII is limited, in terms of number of active blocks. The results of this brief are helpful in choosing the best building block between CCII and VCII for each specific application. Finally, for the first time, the CMOS implementation of VCII is also presented. Simulation results with PSPICE using 0.35-μm CMOS technology and supply voltage of ±1.65 V are given to approve the theory.
This paper studies short-selling prior to the release of analyst downgrades in a sample of 670 downgrades of Nasdaq stocks between 2000 and 2001. We find abnormal levels of short-selling in the three ...days before downgrades are publicly announced. Further, we show that this pre-announcement abnormal short-selling is significantly related to the subsequent share price reaction to the downgrade, and especially so for downgrades that prompt the most substantial price declines. Our findings are robust to various controls that might also affect short-selling such as pre-announcement momentum, three-day pre-announcement returns, and announcement-day share price. In addition, the results are independent of scheduled earnings announcements, analyst herding, and non-routine events near downgrades. Further evidence suggests that tipping is more consistent with the data than the prediction explanation which posits that short sellers successfully predict downgrades on the basis of public information about firms’ financial health. Finally, we present evidence that downgraded stocks with high abnormal short-selling perform poorly over the subsequent six months by comparison with those with low abnormal short-selling. Overall, our results support the hypothesis that short sellers are informed traders and exploit profitable opportunities provided by downgrade announcements.
A new low-voltage low-power class-AB second generation voltage conveyor (VCII) is presented. The proposed circuit is based on an improved class-AB flipped voltage follower (FVF) designed by adding a ...simple negative feedback loop to the conventional class-AB circuit. This modification ensures high current drive capability of at least 2 mA for both falling and rising edges of input signal along with very low 2-mΩ output impedance and high accuracy. Benefiting from the new class-AB FVF, the proposed VCII features a very simple implementation, extremely low impedance at Y and Z terminals (2 mQ), high impedance at X terminal (370 kQ) and high accuracy in current and voltage conveying (99% and 98%, respectively). Moreover, it exhibits current drive capability 117.6 times larger than its bias current (17 μA). The circuit occupies 381.5 μm × 197 μm area. The application of the proposed VCII as a voltage integrator is also presented. Simulation results using PSpice and 0.35-μm CMOS technology with ±1.65-V supply voltage are provided to demonstrate the presented theory. A comparison with the literature is also provided.
In this brief, a new circuit topology to realize an electronically tunable grounded capacitor multiplier with extremely low power consumption and low supply voltage requirement is investigated. The ...proposed circuit uses an electronically tunable second generation voltage conveyor (VCII) and a single floating capacitor. Owing to the translinear principle, current gain of VCII is varied through a control current and, as a result, the value of simulated capacitor is also varied. Favorably the obtained gain is temperature insensitive. Both of the required supply voltage and control currents are very low because all transistors are biased in subthreshold region: therefore, electronic tunability is achieved while the power consumption is kept at very low value. In addition, the circuit realization is very simple since only twelve transistors are required. Simulation results, performed at schematic level in 0.18 μm CMOS technology and supply voltage of ±0.3V, are presented. It is shown that a multiplication factor from 1 to 100 is possible while the power consumption varies from 10 nW to 67 nW.
Capacitive multipliers have found wide applications in capacitive interfaces and other analog circuits requiring large value capacitors. Recently a new active building block (ABB) called second ...generation voltage conveyor (VCII) has been proved to be useful in many analog signal processing applications. Due to the interesting features offered by VCII, in this paper a new VCII based implementation of grounded capacitance multiplier is proposed employing two VCIIs, two resistors and one grounded capacitor. The circuit can produce both positive and negative multiplication factors in a range of −50 to +50. Its main features are wide frequency range, high resolution, low series resistance, simple structure, low power consumption and maximum percentage error of 7.8%. The circuit enjoys high frequency range up to 10 MHz, even if it employs a floating capacitor in its structure. The behavior of the proposed circuit is analysed by taking into account also the effects of VCII parasitic elements and non-ideal gains. SPICE simulation results using a 0.35 µm CMOS technology parameters are reported. The proposed circuit has been also experimentally tested by using AD844 as VCII. Measurement results on the standalone capacitance multiplier have shown a mean percentage error of 9% across the entire gain range. Finally, the application of the proposed circuit in realizing a low pass filter is also presented to demonstrate the proposed circuit feasibility.
•A novel anemometric system based on a hot film sensor array is proposed.•Modified Wheatstone bridge sensor interface with auto-balancing capability.•Wind direction and speed measurement capability ...with 0.6m/s sensitivity.•CMOS 0.35μm architecture of the full system is presented.
In this paper we present a novel complete anemometric electronic system based on an array of hot wire sensors, provided by Telecontrolli SME, and a suitable heater feedback that achieves, thanks to a dedicated algorithm, a CMOS integrable portable solution showing a robust design, without moving parts and small dimensions. The sensor interface is implemented by means of a modified Wheatstone bridge architecture with autobalancing capability. Comparisons with a commercial cup anemometer have shown that the proposed architecture, with reduced space occupancy and low power consumption, is suitable to operate in a natural environment in the −20 to +55°C temperature range providing wind speed and direction measurement. Concerning the wind speed, a 0.6m/s sensitivity has been achieved. The integrated CMOS design of the final system is also presented and discussed in the paper.
The vgf gene has been identified as an energy homeostasis regulator. Vgf encodes a 617-aa precursor protein that is processed to yield an incompletely characterized panel of neuropeptides. Until now, ...it was an unproved assumption that VGF-derived peptides could regulate metabolism. Here, a VGF peptide designated TLQP-21 was identified in rat brain extracts by means of immunoprecipitation, microcapillary liquid chromatography-tandem MS, and database searching algorithms. Chronic intracerebroventricular (i.c.v.) injection of TLQP-21 (15 micrograms/day for 14 days) increased resting energy expenditure (EE) and rectal temperature in mice. These effects were paralleled by increased epinephrine and up-regulation of brown adipose tissue β2-AR (β2 adrenergic receptor) and white adipose tissue (WAT) PPAR-delta (peroxisome proliferator-activated receptor delta), β3-AR, and UCP1 (uncoupling protein 1) mRNAs and were independent of locomotor activity and thyroid hormones. Hypothalamic gene expression of orexigenic and anorexigenic neuropeptides was unchanged. Furthermore, in mice that were fed a high-fat diet for 14 days, TLQP-21 prevented the increase in body and WAT weight as well as hormonal changes that are associated with a high-fat regimen. Biochemical and molecular analyses suggest that TLQP-21 exerts its effects by stimulating autonomic activation of adrenal medulla and adipose tissues. In conclusion, we present here the identification in the CNS of a previously uncharacterized VGF-derived peptide and prove that its chronic i.c.v. infusion effected an increase in EE and limited the early phase of diet-induced obesity.
Short-Selling Prior to Earnings Announcements Christophe, Stephen E.; Ferri, Michael G.; Angel, James J.
The Journal of finance (New York),
August 2004, Letnik:
59, Številka:
4
Journal Article
Recenzirano
This paper examines short-sales transactions in the five days prior to earnings announcements of 913 Nasdaq-listed firms. The tests provide evidence of informed trading in pre-announcement ...short-selling because they reveal that abnormal short-selling is significantly linked to post-announcement stock returns. Also, the tests indicate that short-sellers typically are more active in stocks with low book-to-market valuations or low SUEs. The levels of pre-announcement short-selling, however, mostly appear to reflect firm-specific information rather than these fundamental financial characteristics. We believe that these results should encourage financial market regulators to consider providing more extensive and timely disclosures of short-selling to investors.
Bruton's tyrosine kinase (BTK) is essential for B-cell proliferation/differentiation and it is generally believed that its expression and function are limited to bone marrow-derived cells. Here, we ...report the identification and characterization of p65BTK, a novel isoform abundantly expressed in colon carcinoma cell lines and tumour tissue samples. p65BTK protein is expressed, through heterogeneous nuclear ribonucleoprotein K (hnRNPK)-dependent and internal ribosome entry site-driven translation, from a transcript containing an alternative first exon in the 5'-untranslated region, and is post-transcriptionally regulated, via hnRNPK, by the mitogen-activated protein kinase (MAPK) pathway. p65BTK is endowed with strong transforming activity that depends on active signal-regulated protein kinases-1/2 (ERK1/2) and its inhibition abolishes RAS transforming activity. Accordingly, p65BTK overexpression in colon cancer tissues correlates with ERK1/2 activation. Moreover, p65BTK inhibition affects growth and survival of colon cancer cells. Our data reveal that BTK, via p65BTK expression, is a novel and powerful oncogene acting downstream of the RAS/MAPK pathway and suggest that its targeting may be a promising therapeutic approach.
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